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Murashov AK, Pak ES, Mar J, O'Brien K, Fisher-Wellman K, Bhat KM. Paternal Western diet causes transgenerational increase in food consumption in Drosophila with parallel alterations in the offspring brain proteome and microRNAs. FASEB J 2023; 37:e22966. [PMID: 37227156 DOI: 10.1096/fj.202300239rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/26/2023]
Abstract
Several lines of evidence indicate that ancestral diet might play an important role in determining offspring's metabolic traits. However, it is not yet clear whether ancestral diet can affect offspring's food choices and feeding behavior. In the current study, taking advantage of Drosophila model system, we demonstrate that paternal Western diet (WD) increases offspring food consumption up to the fourth generation. Paternal WD also induced alterations in F1 offspring brain proteome. Using enrichment analyses of pathways for upregulated and downregulated proteins, we found that upregulated proteins had significant enrichments in terms related to translation and translation factors, whereas downregulated proteins displayed enrichments in small molecule metabolic processes, TCA cycles, and electron transport chain (ETC). Using MIENTURNET miRNA prediction tool, dme-miR-10-3p was identified as the top conserved miRNA predicted to target proteins regulated by ancestral diet. RNAi-based knockdown of miR-10 in the brain significantly increased food consumption, implicating miR-10 as a potential factor in programming feeding behavior. Together, these findings suggest that ancestral nutrition may influence offspring feeding behavior through alterations in miRNAs.
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Affiliation(s)
- Alexander K Murashov
- Department of Physiology & East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA
| | - Elena S Pak
- Department of Physiology & East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA
| | - Jordan Mar
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Kevin O'Brien
- Department of Biostatistics, College of Allied Health Sciences, East Carolina University, Greenville, North Carolina, USA
| | - Kelsey Fisher-Wellman
- Department of Physiology & East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA
| | - Krishna M Bhat
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
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Bhat A, Ghatage T, Bhan S, Lahane GP, Dhar A, Kumar R, Pandita RK, Bhat KM, Ramos KS, Pandita TK. Role of Transposable Elements in Genome Stability: Implications for Health and Disease. Int J Mol Sci 2022; 23:ijms23147802. [PMID: 35887150 PMCID: PMC9319628 DOI: 10.3390/ijms23147802] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 12/11/2022] Open
Abstract
Most living organisms have in their genome a sizable proportion of DNA sequences capable of mobilization; these sequences are commonly referred to as transposons, transposable elements (TEs), or jumping genes. Although long thought to have no biological significance, advances in DNA sequencing and analytical technologies have enabled precise characterization of TEs and confirmed their ubiquitous presence across all forms of life. These findings have ignited intense debates over their biological significance. The available evidence now supports the notion that TEs exert major influence over many biological aspects of organismal life. Transposable elements contribute significantly to the evolution of the genome by giving rise to genetic variations in both active and passive modes. Due to their intrinsic nature of mobility within the genome, TEs primarily cause gene disruption and large-scale genomic alterations including inversions, deletions, and duplications. Besides genomic instability, growing evidence also points to many physiologically important functions of TEs, such as gene regulation through cis-acting control elements and modulation of the transcriptome through epigenetic control. In this review, we discuss the latest evidence demonstrating the impact of TEs on genome stability and the underling mechanisms, including those developed to mitigate the deleterious impact of TEs on genomic stability and human health. We have also highlighted the potential therapeutic application of TEs.
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Affiliation(s)
- Audesh Bhat
- Centre for Molecular Biology, Central University of Jammu, Jammu 181143, India;
- Correspondence: (A.B.); (T.K.P.)
| | - Trupti Ghatage
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Sonali Bhan
- Centre for Molecular Biology, Central University of Jammu, Jammu 181143, India;
| | - Ganesh P. Lahane
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Arti Dhar
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Rakesh Kumar
- Department of Biotechnology, Shri Mata Vaishnav Devi University, Katra 182320, India;
| | - Raj K. Pandita
- Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
| | - Krishna M. Bhat
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA;
| | - Kenneth S. Ramos
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX 77030, USA;
| | - Tej K. Pandita
- Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX 77030, USA;
- Correspondence: (A.B.); (T.K.P.)
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Chakraborty S, Singh M, Pandita RK, Singh V, Lo CS, Leonard F, Horikoshi N, Moros EG, Guha D, Hunt CR, Chau E, Ahmed KM, Sethi P, Charaka V, Godin B, Makhijani K, Scherthan H, Deck J, Hausmann M, Mushtaq A, Altaf M, Ramos KS, Bhat KM, Taneja N, Das C, Pandita TK. Heat-induced SIRT1-mediated H4K16ac deacetylation impairs resection and SMARCAD1 recruitment to double strand breaks. iScience 2022; 25:104142. [PMID: 35434547 PMCID: PMC9010620 DOI: 10.1016/j.isci.2022.104142] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/16/2022] [Accepted: 03/21/2022] [Indexed: 12/17/2022] Open
Abstract
Hyperthermia inhibits DNA double-strand break (DSB) repair that utilizes homologous recombination (HR) pathway by a poorly defined mechanism(s); however, the mechanisms for this inhibition remain unclear. Here we report that hyperthermia decreases H4K16 acetylation (H4K16ac), an epigenetic modification essential for genome stability and transcription. Heat-induced reduction in H4K16ac was detected in humans, Drosophila, and yeast, indicating that this is a highly conserved response. The examination of histone deacetylase recruitment to chromatin after heat-shock identified SIRT1 as the major deacetylase subsequently enriched at gene-rich regions. Heat-induced SIRT1 recruitment was antagonized by chromatin remodeler SMARCAD1 depletion and, like hyperthermia, the depletion of the SMARCAD1 or combination of the two impaired DNA end resection and increased replication stress. Altered repair protein recruitment was associated with heat-shock-induced γ-H2AX chromatin changes and DSB repair processing. These results support a novel mechanism whereby hyperthermia impacts chromatin organization owing to H4K16ac deacetylation, negatively affecting the HR-dependent DSB repair. H4K16ac deacetylation during hyperthermia is conserved in human, Drosophila, and yeast Dynamic regulation of the chromatin functions during hyperthermia is SIRT1-dependent SIRT1 function is negatively impacted by SMARCAD1 Hyperthermia increases replication stress and impacts DNA resection, impairing DSB repair
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Affiliation(s)
- Sharmistha Chakraborty
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Mayank Singh
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Raj K. Pandita
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Departments of Radiation Oncology, Washington University, St Louis, MO, USA
| | - Vipin Singh
- Biophysics & Structural Genomics Division Saha Institute of Nuclear Physics, Bidhan Nagar, Kolkata, West Bengal 700064, India
- Homi Bhaba National Institute, Mumbai, India
| | - Calvin S.C. Lo
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 Rotterdam, CA, the Netherlands
| | - Fransisca Leonard
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Nobuo Horikoshi
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
- Departments of Radiation Oncology, Washington University, St Louis, MO, USA
| | - Eduardo G. Moros
- Departments of Radiation Oncology, Washington University, St Louis, MO, USA
- Departments of Radiation Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Deblina Guha
- Biophysics & Structural Genomics Division Saha Institute of Nuclear Physics, Bidhan Nagar, Kolkata, West Bengal 700064, India
| | - Clayton R. Hunt
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
- Departments of Radiation Oncology, Washington University, St Louis, MO, USA
| | - Eric Chau
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Kazi M. Ahmed
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Prayas Sethi
- Department of Medical Oncology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Vijaya Charaka
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Biana Godin
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Kalpana Makhijani
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Harry Scherthan
- Bundeswehr Institute of Radiobiology Affiliated to the University of Ulm, Neuherbergstr. 11, 80937 Munich, Germany
| | - Jeanette Deck
- Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Michael Hausmann
- Kirchhoff-Institute for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany
| | - Arjamand Mushtaq
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - Mohammad Altaf
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - Kenneth S. Ramos
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX, USA
| | - Krishna M. Bhat
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Nitika Taneja
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 Rotterdam, CA, the Netherlands
| | - Chandrima Das
- Biophysics & Structural Genomics Division Saha Institute of Nuclear Physics, Bidhan Nagar, Kolkata, West Bengal 700064, India
- Homi Bhaba National Institute, Mumbai, India
- Corresponding author
| | - Tej K. Pandita
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, University of Texas Southwestern Medical Centre, Dallas, TX, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Departments of Radiation Oncology, Washington University, St Louis, MO, USA
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX, USA
- Corresponding author
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Murashov AK, Pak ES, Lin C, Boykov IN, Buddo KA, Mar J, Bhat KM, Neufer PD. Preference and detrimental effects of high fat, sugar, and salt diet in wild-caught Drosophila simulans are reversed by flight exercise. FASEB Bioadv 2021; 3:49-64. [PMID: 33490883 PMCID: PMC7805546 DOI: 10.1096/fba.2020-00079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
High saturated fat, sugar, and salt contents are a staple of a Western diet (WD), contributing to obesity, metabolic syndrome, and a plethora of other health risks. However, the combinatorial effects of these ingredients have not been fully evaluated. Here, using the wild-caught Drosophila simulans, we show that a diet enriched with saturated fat, sugar, and salt is more detrimental than each ingredient separately, resulting in a significantly decreased lifespan, locomotor activity, sleep, reproductive function, and mitochondrial function. These detrimental effects were more pronounced in female than in male flies. Adding regular flight exercise to flies on the WD markedly negated the adverse effects of a WD. At the molecular level, the WD significantly increased levels of triglycerides and caused mitochondrial dysfunction, while exercise counterbalanced these effects. Interestingly, fruit flies developed a preference for the WD after pre-exposure, which was averted by flight exercise. The results demonstrate that regular aerobic exercise can mitigate adverse dietary effects on fly mitochondrial function, physiology, and feeding behavior. Our data establish Drosophila simulans as a novel model of diet-exercise interaction that bears a strong similarity to the pathophysiology of obesity and eating disorders in humans.
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Affiliation(s)
- Alexander K. Murashov
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Elena S. Pak
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Chien‐Te Lin
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Ilya N. Boykov
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Katherine A. Buddo
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
| | - Jordan Mar
- Department of Molecular MedicineUniversity of South FloridaTampaFLUSA
| | - Krishna M. Bhat
- Department of Molecular MedicineUniversity of South FloridaTampaFLUSA
| | - Peter Darrell Neufer
- Department of Physiology & East Carolina Diabetes and Obesity InstituteEast Carolina UniversityGreenvilleNCUSA
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5
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Abstract
Clinicians are often intrigued by the varied manifestations of the gingival tissue. Gingival overgrowth is a common clinical finding and most of them represent a reactive hyperplasia as a direct result of plaque-related inflammatory gingival disease. These types of growth generally respond to good plaque control, removal of the causative irritants, and conservative tissue management. This case series highlights three different cases of localized gingival overgrowth and its management with emphasis on the importance of patient awareness and motivation.
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Affiliation(s)
- Shruti Raizada
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Karnataka, India
| | - Jothi M Varghese
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Karnataka, India
| | - K M Bhat
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Karnataka, India
| | - Kanishk Gupta
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Karnataka, India
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Carta MG, Sancassiani F, Pippia V, Bhat KM, Sardu C, Meloni L. Alexithymia is associated with delayed treatment seeking in acute myocardial infarction. Psychother Psychosom 2013; 82:190-2. [PMID: 23548987 DOI: 10.1159/000341181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 06/16/2012] [Indexed: 11/19/2022]
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Ray B, D'Souza AS, Kumar V, Pugazhandhi B, D'Souza MR, Nayak D, Sushma RK, Shetty P, Singh H, Krishna L, Bhat KM, Rao AC, Chakraborti S, Kumar N, Saxena A. Ovarian development in Wistar rat treated prenatally with single dose diisobutyl phthalate. ACTA ACUST UNITED AC 2013; 113:577-82. [PMID: 23094893 DOI: 10.4149/bll_2012_129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Phthalates are a class of industrial compounds with an array of toxicological properties used in day to day life. Diisobutyl phthalate on (DIBP) is used as an additive to keep the plastics soft or flexible (plasticizer) in nitrocellulose plastic, nail polish, explosives, lacquer manufacturing etc. Although DIBP exposure in humans is generally low, people in adhesive industries and pharmaceutical industries are exposed to higher levels. The aim of this study was to determine the effect of single dose of DIBP on developing ovary of Wistar rat. One hundred and eight adult pregnant Wistar rats were divided into control and experimental groups. Rats in experimental group were given DIBP on day 10, 12 and 14 of gestation at 0.375, 0.75 and 1.25 ml/kg body weight dose intraperitoneally in a single dose. Sections of ovaries collected on day 21 of gestation were stained with hematoxylin and eosin and examined and Masson's trichrome histologically. Sections belonging to the control group showed the presence of oocytes in clusters separated by thin fibrous septa. Degeneration oocytes, empty follicles surrounded by follicular cells without gonocytes in the center were observed in ovarian stroma. Blood vessels in the ovarian stroma were prominent and congested. Around a bunch of follicles total architectural disarray was observed although on special staining fibrosis was not evident. As pregnant women are constantly exposed, effect of DIBP on ovary of a developing fetus would denote the long term consequence in future generations (Fig. 5, Ref. 39).
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Affiliation(s)
- B Ray
- Department of Anatomy, Katsturba Medical College, Manipal, Karnataka, India
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Deshpande N, Bhat KM, Bhat GS, Deshpande A. Randomized, controlled clinical study to evaluate efficacy of novel indigenously designed controlled release flurbiprofen gel system for management of periodontal diseases. Contemp Clin Dent 2013; 4:32-6. [PMID: 23853449 PMCID: PMC3703691 DOI: 10.4103/0976-237x.111591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Background: This randomized, controlled clinical study was planned to evaluate the use of anti-inflammatory drug flurbiprofen in the form of locally delivered controlled release gel in the treatment of periodontal disease. Materials and Methods: The flurbiprofen gel was indigenously prepared in the concentration of 0.3%. The 30 patients with localized periodontal pockets measuring ≥5 mm were randomly divided into three groups. The groups received flurbiprofen gel, flurbiprofen gel after prophylaxis, and placebo gel after oral prophylaxis, respectively. The clinical parameters for plaque and gingival inflammation were evaluated at baseline, 7th day, and 14th day. Results: The results of the study suggested the statistically significant (P < 0.05) improvement in the gingival status of the patients with the use of flurbiprofen gel as an adjunct to scaling and root planing as compared to oral prophylaxis or gel alone. Conclusion: The data demonstrated that the additional use of local drug delivery of flurbiprofen through gel media enhances the positive effects of scaling and root planing and helps in faster resolution of the inflammation.
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Abstract
Stress is an equated response to constant adverse stimuli. At one point or another everybody suffers from stress. Stress is compatible with good health, being necessary to cope with the challenges of everyday life. Problems start when the stress response is inappropriate to the intensity of the challenge. Psychological stress can down regulate the cellular immune response. Communication between the central nervous system and the immune system occurs via a complex network of bidirectional signals linking the nervous, endocrine, and immune systems. Stress disrupts the homeostasis of this network, which in turn, alters immune function. Direct association between periodontal disease and stress remains to be proven, which is partly due to lack of an adequate animal models and difficulty to quantifying the amount and duration of stress and also there are many factors influencing the incidence and severity of periodontal disease. Nevertheless, more recent studies indicate that psychosocial stress represents a risk indicator for periodontal disease and should be addressed before and during treatment. This paper discusses how stress may modulate host response to bacteria and influence the course and progression of periodontal disease.
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Affiliation(s)
- Sachin Goyal
- Department of Periodontics, Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India
| | - Garima Gupta
- Department of Orthodontics and Dentofacial Orthopaedics, Bhojia Dental College and Hospital, Baddi, Himachal Pradesh, India
| | - Betsy Thomas
- Department of Periodontics, Manipal College of Dental Sciences, Manipal, Karnataka, India
| | - K M Bhat
- Department of Periodontics, Manipal College of Dental Sciences, Manipal, Karnataka, India
| | - G S Bhat
- Department of Periodontics, PDS Division, College of Dentistry, University of Dammam, Saudi Arabia
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Carta MG, Bhat KM, Preti A. GABAergic neuroactive steroids: a new frontier in bipolar disorders? Behav Brain Funct 2012; 8:61. [PMID: 23253178 PMCID: PMC3573983 DOI: 10.1186/1744-9081-8-61] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 11/30/2012] [Indexed: 01/27/2023] Open
Abstract
Neurosteroids are synthesized in the brain and modulate brain excitability. There is increasing evidence of their sedative, anesthetic and antiseizure properties, as well as their influence on mood. Currently neurosteroids are classified as pregnane neurosteroids (allopregnanolone and allotetrahydrodeoxycorticosterone), androstane neurosteroids (androstanediol and etiocholanone) or sulfated neurosteroids (pregnenolone sulfate and dehydroepiandrosterone sulfate). Both preclinical and clinical findings indicate that progesterone derivative neurosteroids such as allopregnanolone and allotetrahydrodeoxycorticosterone play a role in mood disorders. Clozapine and olanzapine, which were shown to be effective in stabilizing bipolar disorder, elevate pregnenolone levels in rat hippocampus, cerebral cortex, and serum. In lithium-treated mice, the blood levels of allopregnanolone and pregnenolone were elevated compared to control levels. Women diagnosed with bipolar disorder typically show symptomatic exacerbation in relation to the menstrual cycle, and show vulnerability to the onset or recurrence of mood disorders immediately after giving birth, when the levels of neurosteroid derivatives of progesterone drop. Whereas in women who had recovered from bipolar disorder, the plasma concentration of allopregnanolone was elevated compared to either healthy controls or women with major depressive disorder during the premenstrual period. During depressive episodes, blood level of allopregnanolone is low. Treatment with fluoxetine tends to stabilize the levels of neurosteroids in depression. These findings converge to suggest that these steroids have significant mood-stabilizing effect. This hypothesis is consistent with the observation that a number of anticonvulsants are effective therapies for bipolar disorder, a finding also consistent with the antiseizure properties of neurosteroids. Further exploration of action of neuroactive steroids is likely to open new frontiers in the investigation of the etiology and treatment of mood disorders, particularly bipolar disorders.
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Affiliation(s)
- Mauro Giovanni Carta
- Department of Public Health, Clinical and Molecular Medicine, University of Cagliari and Center for Consultation-Liaison Psychiatry and Psychosomatics University Hospital of Cagliari, Cagliari, Italy.
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Abstract
Animal experimentation is carried out in consultation with the veterinary wing but it is essential that be familiar with experimental protocols of animal model to be able to design an approriate study. This is more so in place where the veterinary facilities are not easily available.Span Rabbits are commonly used as subjects for screening implant material. They have gained favour for their numerous advantages even though they should be ideally used prior to testing in a larger animal model. Though experimentation on rabbits seems to be easy there are many pitfalls. Our endeavor in this article is to integrate all the data about maintaining rabbits as a model and to critically analyze it on the basis of our experimentation.
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Affiliation(s)
- Manjeet Mapara
- Department of Periodontics, MGM Dental College and Hospital, Navi Mumbai, India
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12
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Mura G, Petretto DR, Bhat KM, Carta MG. Schizophrenia: from epidemiology to rehabilitation. Clin Pract Epidemiol Ment Health 2012; 8:52-66. [PMID: 22962559 PMCID: PMC3434422 DOI: 10.2174/1745017901208010052] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 12/26/2011] [Accepted: 01/01/2012] [Indexed: 12/27/2022]
Abstract
Purpose/Objective: We discuss recent evidences about schizophrenia (frequency, onset, course, risk factors and genetics) and their influences to some epidemiological myths about schizophrenia diffuse between psychiatric and psychopathology clinicians. The scope is to evaluate if the new acquisitions may change the rehabilitation approaches to schizophrenia modifying the balance about the neurodevelopmental hypothesis of schizophrenia accepting that the cognitive deficits are produced by errors during the normal development of the brain (neurodevelopmental hypothesis) that remains stable in the course of illness and the neurodegenerative hypothesis according of which they derived from a degenerative process that goes on inexorably. Research Method/Design: A review of the literature about epidemiology of schizophrenia has been performed and the contributions of some of these evidence to neurodevelopmental hypothesis and to rehabilitation has been described. Results: It cannot be definitively concluded for or against the neurodevelopmental or degenerative hypothesis, but efforts in understanding basis of schizophrenia must go on. Until now, rehabilitation programs are based on the vulnerability-stress model: supposing an early deficit that go on stable during the life under favorable circumstances. So, rehabilitation approaches (as neuro-cognitive approaches, social skill training, cognitive-emotional training) are focused on the individual and micro-group coping skills, aiming to help people with schizophrenia to cope with environmental stress factors. Conclusions/Implications: Coping of cognitive deficits in schizophrenia may represents the starting-point for further research on schizophrenia, cohort studies and randomized trials are necessary to defined the range of effectiveness and the outcome of the treatments.
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Affiliation(s)
- Gioia Mura
- Consultation Liaison Psychiatric Unit at the University Hospital of Cagliari, University of Cagliari and AOU Cagliari - Italy
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Ponnaiyan D, Bhat KM, Bhat GS. Comparison of immuno-phenotypes of stem cells from human dental pulp and periodontal ligament. Int J Immunopathol Pharmacol 2012; 25:127-34. [PMID: 22507325 DOI: 10.1177/039463201202500115] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
It has been established that human dental pulp and periodontal ligament contain a population of mesenchymal stem cells (MSCs). However, the phenotypic analysis in terms of putative stem cell markers expressed by these stem cell populations is incomplete. It is relevant to understand whether stem cells derived from closely related tissues are programmed differently. The aim of the present study is to analyze whether these stem cells depict distinct characteristics by gaining insight into differences in their immunophenotype. Dental pulp and periodontal ligament tissue samples were obtained from extracted impacted wisdom teeth. Cell cultures were analyzed for surface and intracellular markers by indirect immunoflourescence. Detailed immunophenotype analysis was carried out by flow cytometry using relevant markers. The present study data shows dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) expressed embryonic stem (ES) cell markers Oct-4, Nanog and mesodermal marker Vimentin by indirect immunoflourescence. PDLSCs, however, had a weak expression of Nanog. Immunophenotyping revealed strong expression of MSC markers (CD73, CD90) in DPSCs and PDLSCs. Differences were observed in expression of stemness-related markers. DPSCs displayed increased percentages of SSEA4, CD13 and CD166 and decreased CD9 expression compared to PDLSCs. Both stem cells express common MSC markers, different levels of expression suggests there might be more than one stem cell population existing within these tissues which differ in their embryonic status, and DPSCs are a more primitive stem cell population in comparison to PDLSCs.
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Affiliation(s)
- D Ponnaiyan
- Department of Periodontics, S.R.M Dental College and Hospital, Chennai, Tamil Nadu, India.
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Carta MG, Sorbello O, Moro MF, Bhat KM, Demelia E, Serra A, Mura G, Sancassiani F, Piga M, Demelia L. Bipolar disorders and Wilson's disease. BMC Psychiatry 2012; 12:52. [PMID: 22646910 PMCID: PMC3419066 DOI: 10.1186/1471-244x-12-52] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 05/08/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The aim of this study was to determine the risk for Bipolar Disorder (BD) in Wilson's disease (WD) and to measure the impaired Quality of Life (QL) in BD with WD using standardized psychiatric diagnostic tools and a case control design. METHODS This was a case control study. The cases were 23 consecutive patients with WD treated at the University Hospital in Cagliari, Italy, and the controls were 92 sex- and age-matched subjects with no diagnosis of WD who were randomly selected from a database used previously for an epidemiological study. Psychiatric diagnoses according to DSM-IV criteria were determined by physicians using structured interview tools (ANTAS-SCID). QL was measured by means of SF-12. RESULTS Compared to controls, WD patients had lower scores on the SF-12 and higher lifetime prevalence of DSM-IV major depressive disorders (OR = 5.7, 95% CI 2.4-17.3) and bipolar disorders (OR = 12.9, 95% CI 3.6-46.3). BD was associated with lower SF-12 in WD patients. CONCLUSIONS This study was the first to show an association between BD and WD using standardized diagnostic tools and a case control design. Reports in the literature about increased schizophrenia-like psychosis in WD and a lack of association with bipolar disorders may thus have been based on a more inclusive diagnosis of schizophrenia in the past. Our findings may explain the frequent reports of loss of emotional control, hyperactivity, loss of sexual inhibition, and irritability in WD patients. This study was limited by a small sample size.
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Affiliation(s)
| | | | | | - Krishna M Bhat
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
| | | | | | - Gioia Mura
- University of Cagliari, Italy, Cagliari, Italy
| | | | - Mario Piga
- University of Cagliari, Italy, Cagliari, Italy
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Mura G, Bhat KM, Pisano A, Licci G, Carta MG. Psychiatric symptoms and quality of life in systemic sclerosis. Clin Pract Epidemiol Ment Health 2012; 8:30-5. [PMID: 22550545 PMCID: PMC3339425 DOI: 10.2174/1745017901208010030] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Systemic sclerosis (SSc) is a rare conjunctive tissue disorder characterized by fibrosis of the skin and internal organs, and vascular obliteration phenomena. Patients with SSc often experience elevated symptoms of psychological distress, determined by the disfiguration, the pain, the fatigue sensation, and the difficult in daily life occupations. The characteristics of the disease may influence the perceived quality of life (QoL) in people with SSc. METHODS This is a narrative review aiming to define the amount of impairment of Quality of Life in patients with Systemic Sclerosis and the component of this impairment due to depressive or other psychiatric symptoms. The search of the significant articles was carried out in PubMed for the key words "Psychiatric symptoms and Systemic Sclerosis"; "Quality of life and Systemic Sclerosis"; "Depressive Disorders and Systemic Sclerosis". RESULTS Psychiatric symptoms are frequents in patients with SSc, but pain, fatigue, disability, body changes don't appear to explain the high prevalence of psychiatric comorbidity in SSc. Many studies founded a significant impairment in SSc patients' QoL, and despite the undeniable correlation between physical symptoms and SSc patients' QoL, mental health was found significantly impaired. DISCUSSION The high rate of depression seems to strictly correlate with poor quality of life, and this finding needs more research to establish the cause of such a correlation. Patients' point of view regarding their health-related QoL could help physicians to enlarge the knowledge about physical and mental correlates of the disease, and to fit therapies as patient required. Particular attention must be given to provide the patient with correct information, in order to mitigate the anxious state on disease course, and to enhance coping skills of the patients.
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Affiliation(s)
- G Mura
- Consultation Liaison Psychiatric Unit at the University Hospital of Cagliari, University of Cagliari and AOU. Cagliari - Italy
| | - Krishna M Bhat
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - A Pisano
- Consultation Liaison Psychiatric Unit at the University Hospital of Cagliari, University of Cagliari and AOU. Cagliari - Italy
| | - G Licci
- Consultation Liaison Psychiatric Unit at the University Hospital of Cagliari, University of Cagliari and AOU. Cagliari - Italy
| | - MG Carta
- Consultation Liaison Psychiatric Unit at the University Hospital of Cagliari, University of Cagliari and AOU. Cagliari - Italy
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16
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Carta MG, Tondo L, Balestrieri M, Caraci F, dell'Osso L, Di Sciascio G, Faravelli C, Hardoy MC, Lecca ME, Moro MF, Bhat KM, Casacchia M, Drago F. Sub-threshold depression and antidepressants use in a community sample: searching anxiety and finding bipolar disorder. BMC Psychiatry 2011; 11:164. [PMID: 21985128 PMCID: PMC3206417 DOI: 10.1186/1471-244x-11-164] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Accepted: 10/10/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND To determine the use of antidepressants (ADs) in people with sub-threshold depression (SD); the lifetime prevalence of mania and hypomania in SD and the link between ADs use, bipolarity and anxiety disorders in SD. STUDY DESIGN community survey. STUDY POPULATION samples randomly drawn, after stratification from the adult population of municipal records. SAMPLE SIZE 4999 people from seven areas within six Italian regions. Tools: Questionnaire on psychotropic drug consumption, prescription; Structured Clinical Interview NP for DSM-IV modified (ANTAS); Hamilton Depression Rating Scale (HAM-D); Mood Disorder Questionnaire (MDQ); Short Form Health Survey (SF-12). SD definition: HAM-D > 10 without lifetime diagnosis of Depressive Episode (DE). RESULTS SD point prevalence is 5.0%. The lifetime prevalence of mania and hypomania episodes in SD is 7.3%. Benzodiazepines (BDZ) consumption in SD is 24.1%, followed by ADs (19.7%). In SD, positive for MDQ and comorbidity with Panic Disorder (PD) or Generalized Anxiety Disorders (GAD) are associated with ADs use, whereas the association between a positive MDQ and ADs use, without a diagnosis of PD or GAD, is not significant. Only in people with DE the well-being (SF-12) is higher among those using first-line antidepressants compared to those not using any medication. In people with SD no significant differences were found in terms of SF-12 score according to drug use. CONCLUSIONS This study suggests caution in prescribing ADs to people with SD. In people with concomitant anxiety disorders and SD, it should be mandatory to perform a well-designed assessment and evaluate the presence of previous manic or hypomanic symptoms prior to prescribing ADs.
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Affiliation(s)
- Mauro G Carta
- Department of Public Health, University of Cagliari, Cagliari, Italy.
| | - Leonardo Tondo
- Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
| | - Matteo Balestrieri
- Inter-University Center for Behavioural Neurosciences, DPMSC, University of Udine, Udine, Italy
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Italy
| | - Liliana dell'Osso
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Pisa, Italy
| | - Guido Di Sciascio
- Department of Neurological and Psychiatric Sciences, University of Bari, Bari, Italy
| | - Carlo Faravelli
- Department of Neurology and Psychiatry, Florence University, Firenze, Italy
| | - Maria Carolina Hardoy
- Department of Public Health, University of Cagliari, Cagliari, Italy,Department of Psychiatry, Reald University, Vlore, Albania
| | - Maria E Lecca
- Department of Public Health, University of Cagliari, Cagliari, Italy
| | | | - Krishna M Bhat
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Massimo Casacchia
- Department of Science of Health, University of L'Aquila, L'Aquila, Italy
| | - Filippo Drago
- Department of Drug Sciences, University of Catania, Italy
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17
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Hardoy MC, Cadeddu M, Serra A, Moro MF, Mura G, Mellino G, Bhat KM, Altoé G, Usai P, Piga M, Carta MG. A pattern of cerebral perfusion anomalies between major depressive disorder and Hashimoto thyroiditis. BMC Psychiatry 2011; 11:148. [PMID: 21910915 PMCID: PMC3184264 DOI: 10.1186/1471-244x-11-148] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 09/13/2011] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND This study aims to evaluate relationship between three different clinical conditions: Major Depressive Disorders (MDD), Hashimoto Thyroiditis (HT) and reduction in regional Cerebral Blood Flow (rCBF) in order to explore the possibility that patients with HT and MDD have specific pattern(s) of cerebral perfusion. DESIGN Analysis of data derived from two separate data banks. SAMPLE 54 subjects, 32 with HT (29 women, mean age 38.8 ± 13.9); 22 without HT (19 women, mean age 36.5 ± 12.25). ASSESSMENT Psychiatric diagnosis was carried out by Simplified Composite International Diagnostic Interview (CIDIS) using DSM-IV categories; cerebral perfusion was measured by (99 m)Tc-ECD SPECT. Statistical analysis was done through logistic regression. RESULTS MDD appears to be associated with left frontal hypoperfusion, left temporal hypoperfusion, diffuse hypoperfusion and parietal perfusion asymmetry. A statistically significant association between parietal perfusion asymmetry and MDD was found only in the HT group. CONCLUSION In HT, MDD is characterized by a parietal flow asymmetry. However, the specificity of rCBF in MDD with HT should be confirmed in a control sample with consideration for other health conditions. Moreover, this should be investigated with a longitudinally designed study in order to determine a possible pathogenic cause. Future studies with a much larger sample size should clarify whether a particular perfusion pattern is associated with a specific course or symptom cluster of MDD.
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Affiliation(s)
| | | | - Alessandra Serra
- Department of Internal Medicine, University of Cagliari, Cagliari, Italy
| | | | - Gioia Mura
- Department of Public Health, University of Cagliari, Cagliari, Italy
| | - Gisa Mellino
- Department of Public Health, University of Cagliari, Cagliari, Italy
| | - Krishna M Bhat
- Department of Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Gianmarco Altoé
- Department of Psychology, University of Cagliari, Cagliari, Italy
| | - Paolo Usai
- Department of Internal Medicine, University of Cagliari, Cagliari, Italy
| | - Mario Piga
- Department of Internal Medicine, University of Cagliari, Cagliari, Italy
| | - Mauro G Carta
- Department of Public Health, University of Cagliari, Cagliari, Italy
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18
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Janodia MD, Jagadeesh PC, Bhat KM, Udupa N, Pol S. Business method patents: A primer. J Young Pharm 2009. [DOI: 10.4103/0975-1483.59332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Abstract
AIM To describe the diagnosis and management of tooth 22 with a necrotic pulp and severe periodontal destruction associated with a deep palatogingival groove extending to the root apex. SUMMARY Palatogingival grooves are uncommon in maxillary lateral incisors, but when present may contribute to the pathogenesis of periodontal and endodontic lesions. In the present case, the prognosis was considered poor, as the patient presented with a deep probing defect, advanced bone loss and grade III mobility of tooth 22. Root canal treatment was performed, followed by periodontal surgery, during which the groove was conditioned and sealed with conventional glass-ionomer cement and the osseous defect filled with indigenously prepared hydroxyapatite. The 18 month post-operative follow up showed substantial resolution of the osseous defect with gain in attachment and decreased tooth mobility. KEY LEARNING POINTS Teeth with deep palatogingival grooves may be significantly compromised with severe periodontal and periapical bone loss. Following thorough evaluation, the careful application of endodontic and periodontal surgical procedures may restore satisfactory function.
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Affiliation(s)
- N V Ballal
- Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Manipal, Karnataka, India.
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20
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Pratibha PK, Bhat KM, Bhat GS. Oral malodor: a review of the literature. J Dent Hyg 2006; 80:8. [PMID: 16953989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Oral malodor or halitosis is any unpleasant odor emerging from the mouth that is detected by others. Many patients experience extreme discomfort and embarrassment and therefore seek help for this problem. Oral causes, such as poor oral hygiene, periodontal disease, tongue coating, food impaction, unclean dentures, faulty restorations, and dry mouth, are far more common than nonoral causes of malodor. Management may include simple measures such as scaling and root planing, instructions in oral hygiene, tongue cleaning, and mouth rinsing. This paper reviews the current knowledge, etiology, diagnosis, and possible treatment strategies for oral malodor. Emphasis is placed on the recognition of the dental hygienist as a specialist in aspects of patient care and instruction, which relate to the prevention and control of oral malodor.
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Affiliation(s)
- P K Pratibha
- Department of Periodontics, Manipal College of Dental Sciences, Manipal Academy of Higher Education, Manipal, India.
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21
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Abstract
A simple and rapid HPLC assay method for the estimation of meloxicam in plasma was developed. The method totally eliminated the solvent extraction procedure. The plasma proteins were precipitated using perchloric acid (70%) and acetonitrile mixture (1:1 v/v) and the supernatant was directly injected to the HPLC system. The separation was achieved on a Lichrospher C18 5 micron (125x4.0 mm) analytical column with a mobile phase of sodium acetate buffer (pH 3.3, 170 mmol):acetonitrile (62:38 v/v) mixture. Detection was by UV detector at 355 nm. The retention time observed for meloxicam and piroxicam (internal standard) were at 6.0 and 4.0 min, respectively. The response was linear over a range of 50-1500 ng x ml(-1) in human plasma. The method was simple, specific, precise and accurate. The method was also used for the bioequivalence study of meloxicam formulation in healthy, human, Indian, male volunteers.
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Affiliation(s)
- Bhavesh Dasandi
- Synchron Research Services Pvt. Ltd., Sarkhej Gandhinagar Highway, Bodakdev, 380 054, Ahmedabad, India
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22
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Abstract
The bipotential Ganglion Mother Cells, or GMCs, in the Drosophila CNS asymmetrically divide to generate two distinct post-mitotic neurons. Here, we show that the midline repellent Slit (Sli), via its receptor Roundabout (Robo), promotes the terminal asymmetric division of GMCs. In GMC-1 of the RP2/sib lineage, Slit promotes asymmetric division by down regulating two POU proteins, Nubbin and Mitimere. The down regulation of these proteins allows the asymmetric localization of Inscuteable, leading to the asymmetric division of GMC-1. Consistent with this, over-expression of these POU genes in a late GMC-1 causes mis-localization of Insc and symmetric division of GMC-1 to generate two RP2s. Similarly, increasing the dosage of the two POU genes in sli mutant background enhances the penetrance of the RP2 lineage defects whereas reducing the dosage of the two genes reduces the penetrance of the phenotype. These results tie a cell-non-autonomous signaling pathway to the asymmetric division of precursor cells during neurogenesis.
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Affiliation(s)
- B Mehta
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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23
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Bhat KM, van Beers EH, Bhat P. Sloppy paired acts as the downstream target of wingless in the Drosophila CNS and interaction between sloppy paired and gooseberry inhibits sloppy paired during neurogenesis. Development 2000; 127:655-65. [PMID: 10631185 DOI: 10.1242/dev.127.3.655] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Wingless (Wg) and other Wnt proteins play a crucial role in a number of developmental decisions in a variety of organisms. In the ventral nerve cord of the Drosophila embryo, Wg is non-autonomously required for the formation and specification of a neuronal precursor cell, NB4-2. NB4-2 gives rise to a well-studied neuronal lineage, the RP2/sib lineage. While the various components of the Wg-signaling pathway are also required for generating NB4-2, the target gene(s) of this pathway in the signal-receiving cell is not known. In this paper, we show that sloppy paired 1 and sloppy paired 2 function as the downstream targets of the Wg signaling to generate the NB4-2 cell. Thus, while the loss-of-function mutations in wg and slp have the same NB4-2 formation and specification defects, these defects in wg mutants can be rescued by expressing slp genes from a heterologous promoter. That slp genes function downstream of the Wg signaling is also indicated by the result that expression of slp genes is lost from the neuroectoderm in wg mutants and that ectopic expression of wg induces ectopic expression of slp. Finally, previous results show that Gooseberry (Gsb) prevents Wg from specifying NB4-2 identity to the wg-expressing NB5-3. In this paper, we also show that gsb interacts with slp and prevents Slp from specifying NB4-2 identity. Overexpression of slp overcomes this antagonistic interaction and respecifies NB5-3 as NB4-2. This respecification, however, can be suppressed by a simultaneous overexpression of gsb at high levels. This mechanism appears to be responsible for specifying NB5-3 identity to a row 5 neuroblast and preventing Wg from specifying NB4-2 identity to that cell.
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Affiliation(s)
- K M Bhat
- Department of Cell Biology, Emory University School of Medicine, Emory University, Atlanta, GA 30322, USA.
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24
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Abstract
Cell intrinsic and cell extrinsic factors mediate asymmetric cell divisions during neurogenesis in the Drosophila embryo. In the NB4-2->GMC-1->RP2/sib lineage, one of the well-studied neuronal lineages in the ventral nerve cord, the Notch (N) signaling interacts with the asymmetrically localized Numb (Nb) to specify sibling neuronal fates to daughter cells of GMC-1. In this current study, we have investigated asymmetric cell fate specifications by N and Nb in the context of cell cycle. We have used loss-of-function mutations in N and nb, cell division mutants cyclinA (cycA), regulator of cyclin A1 (rca1) and string/cdc25 phosphatase (stg), and the microtubule destabilizing agent, nocodazole, to investigate this issue. We report that the loss of cycA, rca1 or stg leads to a block in the division of GMC-1, however, this GMC-1 exclusively adopts an RP2 identity. While the loss of N leads to the specification of RP2 fates to both progeny of GMC-1 and loss of nb results in the specification of sib fates to these daughter cells, the GMC-1 in the double mutant between nb and cycA assumes a sib fate. These epistasis results indicate that both N and nb function downstream of cell division genes and that progression through cell cycle is required for the asymmetric localization of Nb. In the absence of entry to metaphase, the Nb protein prevents the N signaling from specifying sib fate to the RP2/sib precursor. These results are also consistent with our finding that the sib cell is specified as RP2 in N; nb double mutants. Finally, our results show that nocodazole-arrested GMC-1 in wild-type embryos randomly assumes either an RP2 fate or a sib fate. This suggests that microtubules are involved in mediating the antagonistic interaction between Nb and N during RP2 and sib fate specification.
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Affiliation(s)
- P Wai
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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25
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Abstract
The relatively simple central nervous system (CNS) of the Drosophila embryo provides a useful model system for investigating the mechanisms that generate and pattern complex nervous systems. Central to the generation of different types of neurons by precursor neuroblasts is the initial specification of neuroblast identity and the Drosophila segment polarity genes, genes that specify regions within a segment or repeating unit of the Drosophila embryo, have emerged recently as significant players in this process. During neurogenesis the segment polarity genes are expressed in the neuroectodermal cells from which neuroblasts delaminate and they continue to be expressed in neuroblasts and their progeny. Loss-of-function mutations in these genes lead to a failure in the formation of neuroblasts and/or specification of neuroblast identity. Results from several recent studies suggest that regulatory interactions between segment polarity genes during neurogenesis lead to an increase in the number of neuroblasts and specification of different identities to neuroblasts within a population of cells.
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Affiliation(s)
- K M Bhat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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26
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Koshy C, Varma BR, Bhat KM. Evaluation of efficacy of Sofscale. A clinical and SEM study. Indian J Dent Res 1999; 10:63-7. [PMID: 10865393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Efficacy of Sofscale in the case of removal of calculus from the root surface as claimed by manufacturers was evaluated in the present study. 32 patients suffering from chronic periodontitis, having calculus deposits in the lower incisors were selected for the study. A double blind study was conducted to evaluate the ease with which calculus could be removed. In the second part of study, a SEM study of the root surface subjected to root planing alone and root planing after application of Sofscale was done to see whether any remnants of calculus was left behind. In the double blind study conducted on 32 patients, it was found in 21 patients, calculus could be removed with greater ease and less time in experimental area compared to the control. 17 patients were able to correctly identify the product side as easier to Sofscale. Patients did not complain of increased sensitivity of teeth or discomfort following application of Sofscale. Under SEM the root surface after root planing showed the presence of smear layer whereas after Sofscale application root surface appeared devoid of smear layer. No other significant difference were noticed between the root surfaces.
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Affiliation(s)
- C Koshy
- Department of Periodontics, College of Dental Surgery, Manipal, India
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27
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Abstract
In a variety of tissues in eukaryotes, multipotential stem cells are responsible for maintaining a germinal population and generating a differentiated progeny. The Drosophila germline is one such tissue where a continuous supply of eggs or sperm relies on the normal functioning of stem cells. Recent studies have implicated a possible role for the posterior determinant gene nanos (nos) in stem cells. Here, I report that nanos is required in the Drosophila female germline as well as in the male germline. In the female, nos is required for the functioning of stem cells. In nos mutants, while the stem cells are specified, these cells divide only a few times at the most and then degenerate. The loss of germline stem cells in nos mutant mothers appears to be due to a progressive degeneration of the plasma membrane. Furthermore, following germ cell loss, the germaria in the nos mutant mothers appear to carry on massive mitochondrial biogenesis activity. Thus, the syncytia of such germaria are filled with mitochondria. In the male germline, the male fertility assay indicates that nos appears to be also required for the maintenance of stem cells. In these mutant males, spermatogenesis is progressively affected and these males eventually become sterile. These results indicate novel requirements for nos in the Drosophila germline.
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Affiliation(s)
- K M Bhat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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28
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Thomas BS, Varma BR, Bhat KM. Efficacy of minocycline as a root conditioner in comparison to citric acid and tetracycline. An in vitro evaluation. Indian J Dent Res 1999; 10:69-75. [PMID: 10865394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
This study compared the root surface characteristics produced by Minocycline HCl, Citric acid and Tetracycline HCl. when used as a root conditioner. This study included 5 groups of 10 extracted teeth each with advanced periodontal disease. Diseased root surfaces of group B,C,D and E were planed with Gracy curets and solutions of Citric acid, Tetracycline HCl, Monocycline Hcl and Tween 80 of PH 2.5, were applied to the surface in respective groups with cotton pellets for 5 mts. Group A was not subjected to root planning or application of any root conditioner and was used as a control. The teeth in all five groups were then washed, sectioned processed and examined under scanning electron microscope. These results revealed that the surfaces of acid treated sites differed from each other and with specimens treated sites differed from each other and with specimens treated with root panning alone. The efficacy of Minocycline and tetracycline in the removal of smear layer and exposure of dentinal tubules were comparable and Minocycline HCl though not as effective as Citric acid can probably be recommended in view of its antibactrial activity, anti collagense and substantivity properties.
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Affiliation(s)
- B S Thomas
- Department of Periodontics, College of Dental Surgery, Manipal, India
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29
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Abstract
The Drosophila Frizzled (Fz) and Frizzled2 (DFz2) proteins function as receptors for Wingless (Wg) in tissue culture cells. While previous results indicate that loss of function for fz has tissue polarity defects, loss-of-function effects of Dfz2 are not known. Here, we have examined the requirements of fz and Dfz2 during neurogenesis. Our results indicate that both Fz and DFz2 function in Wg signaling, and loss of either of the two affects the same subset of neuroblasts as those affected by loss of wg. While these defects are partially penetrant in embryos lacking either fz or Dfz2, the penetrance is significantly enhanced in embryos lacking both. Since the penetrance of the CNS phenotypes is not complete in double mutants, additional components that allow some degree of Wg signaling must exist in vivo.
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Affiliation(s)
- K M Bhat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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30
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Ranadive KS, Bhat KM. Local antimicrobial delivery in periodontal therapy. Indian J Dent Res 1998; 9:124-30. [PMID: 10530199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Treatment strategies towards periodontal diseases have evolved to eliminate specific pathogens or suppress destructive host response. The inherent activity of the antibiotic against the target microorganism and various Pharmacokinetic parameters such as potency, permeability, intrinsic efficacy, and substantivity of the drug dictate the success of the therapeutic outcome. However selection of an appropriate delivery system is an important factor. Rapid advances in molecular biology have helped to overcome the disadvantages of systemic and topical applications, by direct placement of antimicrobial agent (s) into subgingival sites, thus minimizing antimicrobial impact on non-oral body sites. As periodontitis is a 'localized' disease condition it is amenable to localized drug treatments. By means of controlled local delivery from within the periodontal pocket, a single administration of a few milligram of an antibacterial agent can maintain therapeutic concentrations within the crevicular fluid for a longer period of time than any other mode of delivery. This paper shall review the different local delivery systems along with the commonly employed drugs through these delivery systems.
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Affiliation(s)
- K S Ranadive
- Department of Periodontology, College of Dental Surgery, Manipal, India
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31
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Rajesh KS, Mohanty M, Varma BR, Bhat KM. Efficacy of Chitra granule and powder (hydroxyapatite) in alveolar bone regeneration in rabbits. A histological evaluation. Indian J Dent Res 1998; 9:59-65. [PMID: 10530192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
The reconstruction or restoration of osseous defects caused by inflammatory periodontal disease is a continuing challenge in periodontal therapy. Great strides are being made to this effect using alloplasts such as hydroxyapatite. The present study was designed in Newzealand dwarf rabbits to observe the biologic response of periodontal tissues to synthetically prepared hydroxyapatite in both powder and granule forms by Srichitra Tirunal Institute for Medical Sciences & Technology, Trivandrum and to compare it with that of a commercially available, pure resorbable hydroxyapatite, OsteoGen (HA Resorb). The test materials were implanted in the artificially created bonydefects in the mandible via an intraoral approach. The wounds were allowed to heal upto 26 weeks postimplantation. The clinical evaluation at 12 weeks and 26 weeks postimplantation revealed neither any evidence of inflammation, infection or abscess formation nor any exposure or exfoliation of test materials. The histological examination of the implant sites at 12 and 26 weeks postimplantation revealed varying extent of formation of new osseous tissue and periodontal fibers. A comparison between test materials and control suggested that Chitra granules exhibit a relatively greater potential for newbone and periodontal fibre formation.
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Affiliation(s)
- K S Rajesh
- Department of Periodontics, Yenepoya Dental College, Mangalore, India
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32
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Bhat KM. Cell-cell signaling during neurogenesis: some answers and many questions. Int J Dev Biol 1998; 42:127-39. [PMID: 9551858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Development of a multicellular organism requires that cells communicate with each other in order to regulate their growth, organize into tissues and coordinate their function. This cell-cell communication is mediated by signals cells receive (or send) between each other and from the environment. The signaling can be a short range remote signaling (through secreted signaling molecules), contact signaling (via plasma membrane bound molecules, gap junctions) or a long range signaling (through hormones). In this article, I have reviewed the recent advances on the role of cell-cell signaling in the development of the embryonic nervous system of the fruitfly Drosophila melanogaster and discussed some of the open questions raised by these studies. It discusses the contributions of the neurogenic genes Notch and Delta and the signaling pathways controlled by wingless, patched and hedgehog in neuroblast formation, neuroblast identity specification and neuroblast lineage elaboration.
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Affiliation(s)
- K M Bhat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Rajesh KS, Varma BR, Bhat KM. Metastasis to maxillary gingiva from carcinoma of breast. A case report. Indian J Dent Res 1998; 9:23-7. [PMID: 10530189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
A rare case of metastatic infiltrating duct carcinoma involving gingiva in relation to maxillary left canine-premolar of a 40 year old female is presented. The unilateral gingival enlargement in canine-premolar region was quite unusual. Pertinent history and histological examination revealed that the tumor was a metastatic carcinoma, the primary lesion of which was in the breast. The differential diagnosis of gingival enlargements is discussed in this paper. The resemblance of this mass to an inflammatory hyperplastic condition reflects the need for a detailed case history and examination.
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Affiliation(s)
- K S Rajesh
- Department of Periodontics, Yenopoya Dental College, Mangalore, India
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34
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Abstract
In the adult Drosophila ovary the continuous production of eggs depends upon a small group of stem cells located at the anterior tip of the germarium. These stem cells divide asymmetrically to self renew and to generate a cystoblast, which in females is committed to the oocyte differentiation pathway. While much is known about the development of poststem cell cystoblasts, little is known about when stem cells are formed or how their identity is initially established. To investigate these questions we have used the P-M hybrid dysgenesis syndrome as a tool for ablating the "pre-stem cell" progenitors of the stem cells. Our experiments indicate that the pre-stem cells in females assume stem cell identity during the early pupal stage. Our results also suggest a model in which at least two pre-stem cells must be present within an ovariole for the specification of stem cell fate. When only a single pre-stem cell is sequestered by an ovariole, this cell does not assume stem cell identity, but instead follows the cystoblast-cystocyte differentiation pathway.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, New Jersey, USA.
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35
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Bhat KM, Schedl P. Requirement for engrailed and invected genes reveals novel regulatory interactions between engrailed/invected, patched, gooseberry and wingless during Drosophila neurogenesis. Development 1997; 124:1675-88. [PMID: 9165116 DOI: 10.1242/dev.124.9.1675] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During neurogenesis, the transmembrane protein Patched (Ptc) promotes a wingless (wg)-mediated specification of a neuronal precursor cell, NB4-2, by repressing gooseberry (gsb). In this study, novel interactions of these genes with engrailed (en) and invected (inv) during neurogenesis have been uncovered. While in row 4 cells Ptc represses gsb and wg, in row 5 cells en/inv relieve Ptc repression of gsb by a non-autonomous mechanism that does not involve hedgehog (hh). This differential regulation of gsb leads to the specification of NB5-3 and NB4-2 identities to two distinct neuroblasts. The uncoupling of the ptc-gsb regulatory circuit also enables gsb to promote Wg expression in row 5 cells. Our results suggest that the en/inv-->ptc-->gsb-->wg pathway uncovered here and the hh-->wg are distinct pathways that function to maintain wild-type level of Wg. Our results also indicate that Hh is not the only ligand for Ptc and similarly Ptc is not the only receptor for Hh.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, New Jersey 08544, USA.
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36
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Bhat KM. The patched signaling pathway mediates repression of gooseberry allowing neuroblast specification by wingless during Drosophila neurogenesis. Development 1996; 122:2921-32. [PMID: 8787765 DOI: 10.1242/dev.122.9.2921] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Drosophila signaling molecule Wingless (Wg) plays crucial roles in cell-cell communications during development. In the developing nervous system, a previous study has shown that Wg acts non-autonomously to specify the fate of a specific neuronal precursor, NB4-2 (Q. Chu-LaGraff and C. Q. Doe (1993) Science 261, 1594–1597). The lack of autocrine specification of NB4-2 in Wg-expressing cells suggests that the response to Wg is spatially restricted, presumably through the activity of the Wg-receptor. I show that two other proteins, a transcription factor Gooseberry (Gsb) and a transmembrane protein Patched (Ptc), participate in the Wg-mediated specification of NB4-2 by controlling the response to the Wg signal. In gsb mutants, Wg-positive NB5-3 is transformed to NB4-2 in a Wg-dependent manner, suggesting that Gsb normally represses the capacity to respond to the Wg signal. In ptc mutants, Gsb is ectopically expressed in normally Wg-responsive cells, thus preventing the Wg response and consequently the correct specification of NB4-2 does not take place. This conclusion is supported by the observation that NB4-2 can be specified in gsb;ptc double mutants in a Wg-dependent manner. Moreover, ectopic expression of Gsb from the hsp7O-gsb transgene also blocks the response to the Wg signal. I propose that the responsiveness to the Wg signal is controlled by sequential negative regulation, ptc-->gsb-->Wg receptor. The timing of the response to Gsb suggests that the specification of neuroblast identities takes place within the neuroectoderm, prior to neuroblast delamination.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, New Jersey 08544, USA
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Abstract
Multirooted teeth in which chronic periodontitis has progressed to involve the furcation present special problems in treatment. The apical placement of furcation, narrow furcation entrance, concavities on the root surface, and the undesirable root configuration make instrumentation and plaque control difficult. Furcation involvement, when present in maxillary first premolars in particular, presents a poor prognosis as the furcation opens mesiodistally. This study on 100 extracted maxillary first premolars is an attempt to determine the frequency of bifurcation, the proximity of bifurcation to cemento-enamel junction, the depth of concavities on the root trunk and the furcal aspect of root, the diameter of furcation entrance, and the extent of root divergence.
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Affiliation(s)
- I Joseph
- Department of Periodontics, College of Dental Surgery, Manipal, India
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38
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Bhat KM, Farkas G, Karch F, Gyurkovics H, Gausz J, Schedl P. The GAGA factor is required in the early Drosophila embryo not only for transcriptional regulation but also for nuclear division. Development 1996; 122:1113-24. [PMID: 8620838 DOI: 10.1242/dev.122.4.1113] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The GAGA protein of Drosophila was first identified as a stimulatory factor in in vitro transcription assays using the engrailed and Ultrabithorax promoters. Subsequent studies have suggested that the GAGA factor promotes transcription by blocking the repressive effects of histones; moreover, it has been shown to function in chromatin remodeling, acting together with other factors in the formation of nuclease hypersensitive sites in vitro. The GAGA factor is encoded by the Trithorax-like locus and in the studies reported here we have used the maternal effect allele Trl13C to examine the functions of the protein during embryogenesis. We find that GAGA is required for the proper expression of a variety of developmental loci that contain GAGA binding sites in their upstream regulatory regions. The observed disruptions in gene expression are consistent with those expected for a factor involved in chromatin remodeling. In addition to facilitating gene expression, the GAGA factor appears to have a more global role in chromosome structure and function. This is suggested by the spectrum of nuclear cleavage cycle defects observed in Trl13C embryos. These defects include asynchrony in the cleavage cycles, failure in chromosome condensation, abnormal chromosome segregation and chromosome fragmentation. These defects are likely to be related to the association of the GAGA protein with heterochromatic satellite sequences which is observed throughout the cell cycle.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, NJ 08544, USA
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39
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Raju PV, Varma BR, Bhat KM. Periodontal implications of Class II restorations. Clinical and SEM evaluation. Indian J Dent Res 1996; 7:21-7. [PMID: 9495121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
30 subjects with class II silver amalgam restorations were studied to evaluate the influence of these restorations on periodontal health of the adjacent region. The incidence of overhangings were noted. The periodontal changes were recorded with the help of indices. The surface of the restoration and the interface between the restoration and the cavity margin were observed on extracted teeth under SEM. The gingival and periodontal status at the site of the restoration were affected by the restoration and the restoration showed a rough surface as compared to the enamel on SEM examination.
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Affiliation(s)
- P V Raju
- Department of Periodontics, College of Dental Surgery, Manipal, India
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40
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Sheffield PJ, Bhat KM, Owen AJ, Perry B, Sumner IG, Warwicker J. Increased activity of porcine pancreatic phospholipase A2 by designed long-range electrostatic stabilisation of the transition state. Biochem Biophys Res Commun 1995; 216:778-84. [PMID: 7488193 DOI: 10.1006/bbrc.1995.2689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Stabilisation of the catalytic transition state by long-range charge interactions has been tested with mutagenesis for porcine pancreatic phospholipase A2. Electrostatics calculations were used to determine locations which would interact preferentially with one part of the dipolar charge separation that is believed to develop in the transition state. Experiment shows increased enzyme activity relative to wild-type recombinant enzyme for mutants N97D and N101D, consistent with the design.
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41
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Bhat KM, Poole SJ, Schedl P. The miti-mere and pdm1 genes collaborate during specification of the RP2/sib lineage in Drosophila neurogenesis. Mol Cell Biol 1995; 15:4052-63. [PMID: 7623801 PMCID: PMC230644 DOI: 10.1128/mcb.15.8.4052] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have investigated (i) the role of pdm1, a Drosophila POU gene, during the elaboration of the GMC-1-->RP2/sib lineage and (ii) the functional relationship between pdm1 and the closely linked second POU gene, miti-mere, in this lineage. We show that deletion of pdm1 causes a partially penetrant GMC-1 defect, while deletion of both miti and pdm1 results in a fully penetrant defect. This GMC-1 defect in miti- and pdm1- embryos can be rescued by the pdm1 or miti transgene. Rescue is observed only when these genes are expressed at the time of GMC-1 formation. Overexpression of pdm1 or miti well after GMC-1 is formed results in the duplication of RP2 and/or sib cells. Our results indicate that both genes are required for the normal development of this lineage and that the two collaborate during the specification of GMC-1 identity.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, New Jersey 08544, USA
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42
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Bhat KM, Schedl P. The Drosophila miti-mere gene, a member of the POU family, is required for the specification of the RP2/sibling lineage during neurogenesis. Development 1994; 120:1483-501. [PMID: 8050358 DOI: 10.1242/dev.120.6.1483] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Drosophila POU gene miti-mere (previously known as pdm2) has a complex spatial and temporal pattern of expression during early development; initially it is expressed in gap-gene-like pattern, then in 14 stripes and finally in a subset of the cells in the developing CNS and PNS. To study the function of this gene during development, we generated a ‘synthetic anti-morphic mutation’ by expressing a truncated version of the miti protein from a constitutive hsp83 and an inducible hsp70 promoter. We show that these delta miti transgenes behave like classical antimorphic mutations. Using these dominant negative transgenes, together with deletions and a duplication for the gene, we show that miti is required during segmentation and neurogenesis. We have also used temperature-shift experiments with the hsp70 delta miti transgene to demonstrate that miti function in segmentation is distinct and separable from its function during neurogenesis. In segmentation, miti appears to be required in the specification of the segments A2 and A6. In the CNS, miti is required for the elaboration of the NB4-2-->GMC-1-->RP2/sib lineage. miti is initially required in this lineage to establish the identity of the parental ganglion mother cell, GMC-1. miti must then be down-regulated to allow the asymmetric division of GMC-1 into the RP2 and its sibling cell.
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Affiliation(s)
- K M Bhat
- Department of Molecular Biology, Princeton University, New Jersey 08544
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43
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Warwicker J, Mueller-Harvey I, Sumner I, Bhat KM. The activity of porcine pancreatic phospholipase A2 in 20% alcohol/aqueous solvent, by experiment and electrostatics calculations. J Mol Biol 1994; 236:904-17. [PMID: 8114101 DOI: 10.1006/jmbi.1994.1197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The activity of porcine pancreatic phospholipase A2 (pla2), measured at pH 8, is reduced when methanol or ethanol is added to the aqueous solution. Finite difference electrostatics calculations were used to study the effect of modelling mixed solvents on the pKas of histidine 48 and the amino-terminal group, both of which influence the pH-dependence of catalysis. Calculations and experiment indicate that these pKa values cannot account for the activity reduction. Charge separation in the transition state is destabilized in 20% alcohol solvent relative to 100% aqueous solvent. The calculated values, which are combinations of stabilizing and destabilizing contributions, are in qualitative agreement with experiment. Saturating dielectric theory is used to model solvent water ordering in a high electric field, and water dielectric structure is assumed to dominate at the 20% alcohol level. The observed agreement demonstrates the utility of transition state stabilization theory and continuum solvent modelling. It is further suggested that electrostatic effects on kcat contribute to the pH-dependence of activity around pH 7, and to previously reported activity changes for charge mutants.
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Affiliation(s)
- J Warwicker
- Protein Engineering Department, AFRC Institute of Food Research Reading Laboratory, U.K
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44
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Goodenough PW, Bhat KM, Collins ME, Perry BN, Pickersgill RW, Sumner IG, Warwicker J, de Haas GH, Verheij HM. Changes in activity of porcine phospholipase A2 brought about by charge engineering of a major structural element to alter stability. Protein Eng 1991; 4:929-34. [PMID: 1817255 DOI: 10.1093/protein/4.8.929] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have modified the stability of porcine phospholipase A2 by charge engineering. The mutations are situated at the N-terminal of a major helix and are N89D and N89D/E92Q. This engineering has significantly altered the activity of the enzyme to aggregated and monomeric substrates. A N89D/E92K mutant is more stable but considerably less active than wild type. An N89D mutant is more stable and of similar activity to wild type. The substantial change in activity may be due to direct interaction of residue 92 with aggregated substrate or may be via second calcium binding. Second calcium binding may be more probable as activity against monomers is also affected. Additional calcium binding may therefore be an important way of manipulating the activity of phospholipase A2.
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Affiliation(s)
- P W Goodenough
- Protein Engineering Department, AFRC Institute of Food Research, Shinfield, Reading, UK
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45
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Bhat KM, Sumner IG, Perry BN, Collins ME, Pickersgill RW, Goodenough PW. A novel method for the purification of porcine phospholipase A2 expressed in E. coli. Biochem Biophys Res Commun 1991; 176:371-7. [PMID: 1850264 DOI: 10.1016/0006-291x(91)90934-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Porcine phospholipaseA2 expressed in E. coli as a fusion protein was isolated, renatured and specifically cleaved by trypsin as described in (1). Active phospholipaseA2, was purified to homogeneity on a column of PBE-94 over a pH region 7.4-4.5. Using this method, several phospholipase A2 mutant enzymes have now been purified in a single step and all behaved identically during chromatofocusing. The method will therefore be extremely useful not only for those interested in understanding the structure-function relationships of phospholipaseA2 but also for preparing the enzyme in large quantities for industrial and pharmaceutical purposes.
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Affiliation(s)
- K M Bhat
- AFRC Institute of Food Research, Reading Laboratory, Berks, U.K
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46
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Pickersgill RW, Sumner IG, Collins ME, Warwicker J, Perry B, Bhat KM, Goodenough PW. Modification of the stability of phospholipase A2 by charge engineering. FEBS Lett 1991; 281:219-22. [PMID: 2015898 DOI: 10.1016/0014-5793(91)80397-l] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Electrostatic interactions play an important role in stabilizing the folded conformation of globular proteins. Here we predict the change in stability of charge engineered mutants, construct these mutants and compare the predicted change in stability with that observed. The change in stability was correctly predicted for two of the three mutants and the factors responsible for the discrepancy between observation and prediction for the third mutant are discussed.
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Affiliation(s)
- R W Pickersgill
- Protein Engineering Department, AFRC Institute of Food Research, Reading Laboratory, Shinfield, UK
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47
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Bhat KM, Hay AJ, Wood TM, Claeyssens M. Comparison of the mode of action and site specificity of endo-(1,4)-beta-D-glucanases of Penicillium pinophilum using normal, 1-3H-labelled, reduced and chromogenic cello-oligosaccharides. Biochem Soc Trans 1990; 18:638-9. [PMID: 2276486 DOI: 10.1042/bst0180638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- K M Bhat
- Rowett Research Institute, Bucksburn, Aberdeen, U.K
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48
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Bhat KM, Hay AJ, Claeyssens M, Wood TM. Study of the mode of action and site-specificity of the endo-(1----4)-beta-D-glucanases of the fungus Penicillium pinophilum with normal, 1-3H-labelled, reduced and chromogenic cello-oligosaccharides. Biochem J 1990; 266:371-8. [PMID: 2317193 PMCID: PMC1131141 DOI: 10.1042/bj2660371] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The modes of action of the five major endo-(1----4)-beta-D-glucanases (I, II, III, IV and V) purified from Penicillium pinophilum cellulase were compared by h.p.l.c. analysis, with normal, 1-3H-labelled and reduced cello-oligosaccharides and 4-methylumbelliferyl glycosides as substrates. Significant differences were observed in the preferred site of cleavage even when substrates with the same number of glycosidic bonds were compared. Thus, although endoglucanase I was unable to attack normal cello-oligosaccharides shorter than degree of polymerization 6, it hydrolysed reduced cellopentaose to yield cellotriose and cellobi-itol, and it produced cellotriose and 4-methylumbelliferyl glucoside from 4-methylumbelliferyl cellotetraoside. Endoglucanase IV hydrolysed [1-3H]cellotriose but did not attack either cellotri-itol or 4-methylumbelliferyl cellobioside. These and other anomalous results indicated clearly that modification of the reducing glycosyl residue on the cello-oligosaccharides induces in an apparent change in the mode of action of the endoglucanases. It is suggested that, although cello-oligosaccharide derivatives are useful for differentiating and classifying endoglucanases, conclusions on the mechanism of cellulase action resulting from these measurements should be treated cautiously. Unequivocal information on the mode of endoglucanase action on cello-oligosaccharides was obtained with radiolabelled cello-oligosaccharides of degree of polymerization 3 to 5. Indications that transglycosylation was a property of the endoglucanases were particularly evident with the 4-methylumbelliferyl cello-oligosaccharides. Turnover numbers for hydrolysis of the umbelliferyl cello-oligosaccharides were calculated, and these, along with the other analytical data collected on the products of hydrolysis of the normal, reduced and radiolabelled cello-oligosaccharides, suggested that the various endoglucanases had different roles to play in the overall hydrolysis of cellulose to sugars small enough to be transported through the cell membrane.
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Affiliation(s)
- K M Bhat
- Rowett Research Institute, Bucksburn, Aberdeen, U.K
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49
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Chauvaux S, Beguin P, Aubert JP, Bhat KM, Gow LA, Wood TM, Bairoch A. Calcium-binding affinity and calcium-enhanced activity of Clostridium thermocellum endoglucanase D. Biochem J 1990; 265:261-5. [PMID: 2302168 PMCID: PMC1136638 DOI: 10.1042/bj2650261] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Clostridium thermocellum endoglucanase D (EC 3.2.1.4: EGD), which is encoded by the celD gene, was found to bind Ca2+ with an association constant of 2.03 x 10(6) M-1. Ca2+ stimulated the activity of EGD towards swollen Avicel by 2-fold. In the presence of Ca2+, the Kd of the enzyme towards p-nitrophenyl-beta-D-cellobioside and carboxymethylcellulose was decreased by 4-fold. Furthermore, Ca2+ increased the half-life of the enzyme at 75 degrees C from 13 to 47 min. Since the 3' sequence of celD encodes a duplicated region sharing similarities with the Ca2+-binding site of several Ca2+-binding proteins, a deleted clone was constructed and used to purify a truncated form of the enzyme which no longer contained the duplicated region. The truncated enzyme was very similar to EGD expressed from the intact gene with respect to activity, Ca2(+)-binding kinetics and Ca2+ effects on substrate binding and thermostability. Thus the latter parameters do not appear to be mediated through the duplicated conserved region.
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Affiliation(s)
- S Chauvaux
- Unité de Physiologie Cellulaire and URA 1300 CNRS, Départment des Biotechnologies, Institut Pasteur, Paris, France
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50
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Wood TM, McCrae SI, Bhat KM. The mechanism of fungal cellulase action. Synergism between enzyme components of Penicillium pinophilum cellulase in solubilizing hydrogen bond-ordered cellulose. Biochem J 1989; 260:37-43. [PMID: 2549957 PMCID: PMC1138622 DOI: 10.1042/bj2600037] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Studies on reconstituted mixtures of extensively purified cellobiohydrolases I and II and the five major endoglucanases of the fungus Penicillium pinophilum have provided some new information on the mechanism by which crystalline cellulose in the form of the cotton fibre is rendered soluble. It was observed that there was little or no synergistic activity either between purified cellobiohydrolases I and II, or, contrary to previous findings, between the individual cellobiohydrolases and the endoglucanases. Cotton fibre was degraded to a significant degree only when three enzymes were present in the reconstituted enzyme mixture: these were cellobiohydrolases I and II and some specific endoglucanases. The optimum ratio of the cellobiohydrolases was 1:1. Only a trace of endoglucanase activity was required to make the mixture of cellobiohydrolases I and II effective. The addition of cellobiohydrolases I and II individually to endoglucanases from other cellulolytic fungi resulted in little synergistic activity; however, a mixture of endoglucanases and both cellobiohydrolases was effective. It is suggested that current concepts of the mechanism of cellulase action may be the result of incompletely resolved complexes between cellobiohydrolase and endoglucanase activities. It was found that such complexes in filtrates of P. pinophilium or Trichoderma reesei were easily resolved using affinity chromatography on a column of p-aminobenzyl-1-thio-beta-D-cellobioside.
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Affiliation(s)
- T M Wood
- Rowett Research Institute, Bucksburn, Aberdeen, Scotland, U.K
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