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Priya PS, Pratiksha Nandhini P, Vaishnavi S, Pavithra V, Almutairi MH, Almutairi BO, Arokiyaraj S, Pachaiappan R, Arockiaraj J. Rhodamine B, an organic environmental pollutant induces reproductive toxicity in parental and teratogenicity in F1 generation in vivo. Comp Biochem Physiol C Toxicol Pharmacol 2024; 280:109898. [PMID: 38508353 DOI: 10.1016/j.cbpc.2024.109898] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/28/2024] [Accepted: 03/17/2024] [Indexed: 03/22/2024]
Abstract
This study investigated the reproductive toxicity of rhodamine B in zebrafish and its transgenerational effects on the F1 generation. In silico toxicity predictions revealed high toxicity of rhodamine B, mainly targeting pathways associated with the reproductive and endocrine systems. In vivo experiments on zebrafish demonstrated that rhodamine B exposure at a concentration of 1.5 mg/L led to significant impairments in fecundity parameters, particularly affecting females. Histopathological analysis revealed distinct changes in reproductive organs, further confirming the reproductive toxicity of rhodamine B, with females being more susceptible than males. Gene expression studies indicated significant suppression of genes crucial for ovulation in rhodamine B-treated female fish, highlighting hormonal imbalance as a potential mechanism of reproductive toxicity. Furthermore, bioaccumulation studies showed the presence of rhodamine B in both adult fish gonads and F1 generation samples, suggesting transgenerational transfer of the dye. Embryotoxicity studies on F1 generation larvae demonstrated reduced survival rates, lower hatching rates, and increased malformations in groups exposed to rhodamine B. Moreover, rhodamine B induced oxidative stress in F1 generation larvae, as evidenced by elevated levels of reactive oxygen species and altered antioxidant enzyme activity. Neurotoxicity assessments revealed reduced acetylcholinesterase activity, indicating potential neurological impairments in F1 generation larvae. Additionally, locomotory defects and skeletal abnormalities were observed in F1 generation larvae exposed to rhodamine B. This study provides comprehensive evidence of the reproductive toxicity of rhodamine B in adult zebrafish and its transgenerational effects on the F1 generation.
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Affiliation(s)
- P Snega Priya
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur 603203, Chengalpattu District, Tamil Nadu, India
| | - P Pratiksha Nandhini
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur 603203, Chengalpattu District, Tamil Nadu, India
| | - S Vaishnavi
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur 603203, Chengalpattu District, Tamil Nadu, India
| | - V Pavithra
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur 603203, Chengalpattu District, Tamil Nadu, India
| | - Mikhlid H Almutairi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Bader O Almutairi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Selvaraj Arokiyaraj
- Department of Food Science & Biotechnology, Sejong University, Seoul 05006, Republic of Korea
| | - Raman Pachaiappan
- Department of Biotechnology, School of Bioengineering, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur 603203, Chengalpattu District, Tamil Nadu, India
| | - Jesu Arockiaraj
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur 603203, Chengalpattu District, Tamil Nadu, India.
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Priya PS, Pavithra V, Vaishnavi S, Almutairi BO, Arokiyaraj S, Dhanaraj M, Seetharaman S, Arockiaraj J. Application of Bacillus Coagulans as Paraprobiotic Against Acute Hepatopancreatic Necrosis Disease in Shrimp. Probiotics Antimicrob Proteins 2024:10.1007/s12602-024-10230-6. [PMID: 38329695 DOI: 10.1007/s12602-024-10230-6] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
Paraprobiotics, known as non-viable or ghost probiotics, have attracted attention for their benefits over live microbial cells. This study was designed to investigate the paraprobiotic effects of heat-killed Bacillus coagulans on the white leg shrimp Litopenaeus vannamei. The paraprobiotic formulation was prepared in three different concentrations including B. coagulans 1 (107 cells g-1 diet), B. coagulans 2 (108 cells g-1 diet), and B. coagulans 3 (109 cells g-1 diet) through heat inactivation method. Preliminary toxicity assessments revealed that post-larvae shrimps (mean weight ± SE: 0.025 ± 0.007 g) treated with B. coagulans 1, 2 and 3 paraprobiotic formulations exhibited no mortality, confirming the non-toxic nature of the formulated diet. In a 90-day feeding trial involving juvenile shrimps (mean weight ± SE: 0.64 ± 0.05 g), growth parameters and feed conversion ratios improved in all experimental groups. Subsequently, these shrimps were challenged with Vibrio parahaemolyticus, revealing that paraprobiotic-fed shrimps exhibited significant survival rate improvements. Oxidative stress-related enzyme activities, such as superoxide dismutase and catalase, increased in paraprobiotic-fed shrimps post-Vibrio challenge, while the challenged control group showed decreased activity (p < 0.001). Nitric oxide levels are also increased in paraprobiotic-treated shrimp, with B. coagulans 3 showing a significant rise in nitric oxide activity (p < 0.001). This study further demonstrated the positive impact of paraprobiotic treatment on digestive enzymes, immune-related parameters (e.g., total hemocyte count, prophenoloxidase, and respiratory burst activity), and overall disease resistance. These findings suggest that B. coagulans paraprobiotics have the potential to enhance antioxidant, antibacterial, and immune-related responses in L. vannamei, making them a valuable addition to shrimp aquaculture.
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Affiliation(s)
- P Snega Priya
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, Chengalpattu District, Tamil Nadu, 603203, India
| | - V Pavithra
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, Chengalpattu District, Tamil Nadu, 603203, India
| | - S Vaishnavi
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, Chengalpattu District, Tamil Nadu, 603203, India
| | - Bader O Almutairi
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia
| | - Selvaraj Arokiyaraj
- Department of Food Science & Biotechnology, Sejong University, Seoul, 05006, Korea
| | - M Dhanaraj
- Foundation for Aquaculture Innovations and Technology Transfer (FAITT), Kumaran Kudil, Thoraipakkam, Chennai, Tamil Nadu, 600097, India
| | - S Seetharaman
- Foundation for Aquaculture Innovations and Technology Transfer (FAITT), Kumaran Kudil, Thoraipakkam, Chennai, Tamil Nadu, 600097, India
| | - Jesu Arockiaraj
- Toxicology and Pharmacology Laboratory, Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, Chengalpattu District, Tamil Nadu, 603203, India.
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Priya PS, Pavithra V, Vaishnavi S, Pachaiappan R, Kumar TTA, Rady A, Darwish NM, Arokiyaraj S, Karthick Raja Namasivayam S, Arockiaraj J. Understanding the mechanisms and implications of acacetin in mitigating diabetic osteoporosis: Insights from a zebrafish model. Process Biochem 2023; 134:63-74. [DOI: 10.1016/j.procbio.2023.09.019] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2023]
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Chandran A, Priya PS, Meenatchi R, Vaishnavi S, Pavithra V, Ajith Kumar TT, Arockiaraj J. Insights into molecular aspects of pathogenesis and disease management in acute hepatopancreatic necrosis disease (AHPND): An updated review. Fish Shellfish Immunol 2023; 142:109138. [PMID: 37802265 DOI: 10.1016/j.fsi.2023.109138] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/29/2023] [Accepted: 10/02/2023] [Indexed: 10/08/2023]
Abstract
Shrimp aquaculture is a rapidly growing sector that makes a significant economic contribution. However, the aquaculture industry is confronted with significant challenges, and infectious diseases, notably Acute Hepatopancreatic Necrosis Disease (AHPND), have emerged as severe threat. AHPND is caused by pathogens carrying the pVA-1 plasmid, which expresses the PirAB toxin, and it has wreaked havoc in shrimp aquaculture, imposing substantial economic burdens. To address this issue, it is crucial to delve into shrimp's immune responses. Therefore, this comprehensive review offers an in-depth examination of AHPND outbreaks, encompassing various facets such as environmental factors, host susceptibility, and the mechanisms employed by the pathogens. Traditional approaches to combat AHPND, primarily relying on chemicals and antibiotics, have raised concerns related to antibiotic resistance and have demonstrated limited success in disease control. Hence this review spotlights recent advancements in molecular diagnostics, therapeutic agents, and research related to shrimp immunity. Understanding these developments is crucial in the ongoing battle against AHPND. In conclusion, this review underscores the pressing need to comprehend the underlying mechanisms of AHPND pathogenesis and emphasizes the importance of developing comprehensive and effective solutions to combat this devastating disease, which continues to threaten the sustainability of shrimp farming.
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Affiliation(s)
- Abhirami Chandran
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India
| | - P Snega Priya
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India
| | - Ramu Meenatchi
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India
| | - S Vaishnavi
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India
| | - V Pavithra
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India
| | | | - Jesu Arockiaraj
- Department of Biotechnology, Faculty of Science and Humanities, SRM Institute of Science and Technology, Kattankulatur, 603203, Chengalpattu District, Tamil Nadu, India.
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Priya PS, Vaishnavi S, Pavithra V, Pachaiappan R, Barathkumar S, O.Almutairi B, Arokiyaraj S, Arockiaraj J. Graphene oxide decorated daidzein as an oral drug to ameliorate the oxidative stress and glucocorticoid-induced osteoporosis in vivo zebrafish model. J Drug Deliv Sci Technol 2023. [DOI: 10.1016/j.jddst.2023.104278] [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: 02/18/2023]
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Majumdar R, Hariharan K, Vaishnavi S, Sugumar S. Review on Stenotrophomonas maltophilia: an emerging multidrug-resistant opportunistic pathogen. Recent Pat Biotechnol 2022; 16:329-354. [PMID: 35549857 DOI: 10.2174/1872208316666220512121205] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/10/2021] [Accepted: 12/23/2021] [Indexed: 11/22/2022]
Abstract
Stenotrophomonas maltophilia is an opportunistic pathogen that results in nosocomial infections in immunocompromised individuals. These bacteria colonize on the surface of medical devices and therapeutic equipment like urinary catheters, endoscopes, and ventilators, causing respiratory and urinary tract infections. The low outer membrane permeability of multidrug-resistance efflux systems and the two chromosomally encoded β-lactamases present in S.maltophilia are challenging for arsenal control. The cell-associated and extracellular virulence factors in S.maltophilia are involved in colonization and biofilm formation on the host surfaces. The spread of antibiotic-resistant genes in the pathogenic S.maltophilia attributes to bacterial resistance against a wide range of antibiotics, including penicillin, quinolones, and carbapenems. So far, tetracycline derivatives, fluoroquinolones, and trimethoprim-sulfamethoxazole (TMP-SMX) are considered promising antibiotics against S.maltophilia. Due to the adaptive nature of the intrinsically resistant mechanism towards the number of antibiotics and its ability to acquire new resistance via mutation and horizontal gene transfer, it is quite tricky for medicinal contribution against S.maltophilia. The current review summarizes the literary data of pathogenicity, quorum sensing, biofilm formation, virulence factors, and antibiotic resistance of S.maltophilia.
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Affiliation(s)
- Rikhia Majumdar
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - K Hariharan
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - S Vaishnavi
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
| | - Shobana Sugumar
- Department of Genetic Engineering, School of Bioengineering, SRM Institute of Science and Technology, Kattankulathur-603203, Tamilnadu, India
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Thomas J, Soundarya S, Vaishnavi S. Spironolactone in Dermatology: A Mini Review. JPRI 2021. [DOI: 10.9734/jpri/2021/v33i60b34861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spironolactone is a drug, similar in structure to aldosterone and acts as an aldosterone receptor antagonist with an anti-androgenic effect.
This drug has proven to be useful in several dermatological entities, however its use has not been well explored. Its use in diseases such as acne has opened the door to the possibility of new therapies depending on the clinical manifestations of the patients, as well as its possible to use it as a first line treatment. Other diseases associated with the use of spironolactone where its effects have been shown to be useful are hidradenitis suppurativa, hirsutism and female pattern androgenetic alopecia. In this review we discuss the use of spironolactone in different skin diseases that are common in our environment, dosage according to different studies, treatment recommendations and adverse effects; all of the above mentioned in order to use this drug in a daily clinical practice.
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Saravanan A, Kumar PS, Govarthanan M, George CS, Vaishnavi S, Moulishwaran B, Kumar SP, Jeevanantham S, Yaashikaa PR. Adsorption characteristics of magnetic nanoparticles coated mixed fungal biomass for toxic Cr(VI) ions in aquatic environment. Chemosphere 2021; 267:129226. [PMID: 33338712 DOI: 10.1016/j.chemosphere.2020.129226] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/21/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
In this research, the adsorptive removal of Cr(VI) ions from the aquatic environment have been studied using newly synthesized magnetic nanoparticles coated mixed fungal biomass (MNP-FB). Two fungal biomass such as Aspergillus fumigatus and Aspergillus niger were isolated, screened, and utilized as a precursor for making an adsorbent. Molecular characterization of isolated fungal species was recognized using 18S rRNA sequencing. The characterization studies of the MNP-FB were evaluated using Fourier Transform Infrared Spectrophotometer (FTIR) and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analyses. Optimization studies were studied to check the effect of different operating variables such as pH (2.0-9.0), equilibrium time (10-90 min), MNP-FB dosage (0.1-1.0 g/L), temperature (30-60 °C) and concentration of Cr(VI) ions (50-500 mg/L). Additionally, Freundlich isotherm model fits well for the adsorption of Cr(VI) ion using MNP-FB. The adsorption kinetics was interpreted well by Pseudo-first order model. The thermodynamic study concluded that Cr(VI) ions removal by MNP-FB was exothermic and appreciative at low temperatures. The monolayer adsorption efficiency of MNP-FB for Cr(VI) ions was measured as 249.9 mg/g. The current results reveal that MNP-FB has considered being a proficient and economically suitable material for the Cr(VI) ions removal from the water environment.
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Affiliation(s)
- A Saravanan
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - P Senthil Kumar
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India.
| | - M Govarthanan
- Department of Environmental Engineering, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Cynthia Susan George
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India
| | - S Vaishnavi
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - B Moulishwaran
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - S Praveen Kumar
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - S Jeevanantham
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - P R Yaashikaa
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India
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Partheeban I, Chaly P, Priyadarshni I, Junaid M, Nijesh JE, Vaishnavi S. Evaluation of gingival blood as a minimally invasive screening tool for diabetes mellitus among 40–59-year-old adults in dental clinics: A cross-sectional study. Indian J Dent Res 2017; 28:144-150. [DOI: 10.4103/ijdr.ijdr_304_16] [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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Mitha MM, Nijesh JE, Chaly PE, Priyadharshini I, Junaid M, Vaishnavi S. Caries risk assessment among 12-13 year old school-going children of government and private schools of Tirupur district, Tamil Nadu. J Indian Soc Pedod Prev Dent 2016; 34:244-8. [PMID: 27461808 DOI: 10.4103/0970-4388.186745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Dental caries is as ancient as humankind and has the longest association with the dental profession, an association that is punctuated with agony and ecstasy. The agonizing fact is that despite several efforts toward total eradication, this disease is still prevalent. Nevertheless, an ecstatic success of the profession is the global decline in the incidence compared to the yesteryears' epidemics. Hence, predicting dental caries earlier is a boon. One such model to predict is cariogram developed by Bratthall in 1996. AIM The aim of this study was to assess the caries risk among 12-13 year old school-going children of government and private schools of Tirupur district in Tamil Nadu using cariogram computer model. METHODS A cross-sectional survey was carried out among 136 study subjects of 12-13 year of age, who fulfilled the inclusion and exclusion criteria. Data were collected using a predesigned questionnaire and scored according to a standardized protocol. The Chi-square test was used to find differences between caries-related factors and cariogram group. The correlation was acquired using Spearman's correlation. RESULTS Government school study subjects had 56% of chance of avoiding caries whereas the private school study subjects had 66% of chance of avoiding caries in future and the differences were statistically significant (P = 0.001). A negative correlation was observed between the chance to avoid dental caries and cariogram sectors. CONCLUSION The majority of the study subjects from government school belonged to medium-risk category and private school subjects belonged to low-risk category which inferred that private school students have high chance to avoid dental caries compared to government study subjects.
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Affiliation(s)
- Madhu M Mitha
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
| | - J E Nijesh
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
| | - Preetha Elizabeth Chaly
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
| | - Indra Priyadharshini
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
| | - Mohammed Junaid
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
| | - S Vaishnavi
- Department of Public Health Dentistry, Meenakshi Ammal Dental College, Chennai, Tamil Nadu, India
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Larson-Prior LJ, Vaishnavi S, Tamez E, Nolan TS, Ghilardi MF, Raichle ME. Shared networks involved in implicit and explicit motor learning tasks. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)70826-2] [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: 11/29/2022] Open
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Raina SN, Sharma S, Sasakuma T, Kishii M, Vaishnavi S. Novel Repeated DNA Sequences in Safflower (Carthamus tinctorius L.) (Asteraceae): Cloning, Sequencing, and Physical Mapping by Fluorescence in situ Hybridization. J Hered 2005; 96:424-9. [PMID: 15731214 DOI: 10.1093/jhered/esi041] [Citation(s) in RCA: 24] [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: 11/13/2022] Open
Abstract
Two novel repetitive DNA sequences, pCtKpnI-1 and pCtKpnI-2, were isolated from Carthamus tinctorius (2n = 2x = 24) and cloned. Both represent tandemly repeated sequences. The pCtKpnI-1 and pCtKpnI-2 clones constitute repeat units of 343-345 bp and 367 bp, respectively, with 63% sequence heterogeneity between the two. Fluorescence in situ hybridization (FISH) was employed on metaphase chromosomes of C. tinctorius using, simultaneously, pCtKpnI-1 and pCtKpnI-2 repeated sequences. The pCtKpnI-1 sequence was found to be exclusively localized at subtelomeric regions on most of the chromosomes. On the other hand, sequence of the pCtKpnI-2 clone was distributed on two nucleolar and one nonnucleolar chromosome pairs. The satellite, and the intervening chromosome segment between the primary and secondary constrictions, in the two nucleolar chromosome pairs were wholly constituted by pCtKpnI-2 repeated sequence. The pCtKpnI-2 repeated sequence, showing partial homology to intergenic spacer (IGS) of 18S-25S ribosomal RNA genes of an Asteraceae taxon (Centaurea stoebe), and the 18S-25S rRNA gene clusters were located at independent, but juxtaposed sites in the nucleolar chromosomes. Variability in the number, size, and location of the two repeated sequences provided identification of most of the chromosomes in the otherwise not too distinctive homologues within the complement. This article reports the start of a molecular cytogenetics program targeting the genome of safflower, a major world oil crop about whose genetics very little is known.
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Affiliation(s)
- S N Raina
- Kihara Institute for Biological Research and Graduate School of Integrated Sciences, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama 244-0813, Japan.
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Abstract
Behavioral and neurophysiological studies suggest that the brain constructs different representations of space. Among these representations are personal and peripersonal space. Personal space refers to the space occupied by our bodies. Peripersonal space refers to the space surrounding our bodies, which can be reached by our limbs. How these two representations are bound to give a unified sense of space in which humans act is not clear. We tested 10 patients with tactile extinction to investigate this issue. Tactile extinction is an attentional disorder in which patients are unaware of being touched on their contralesional limb if they are also touched simultaneously on their ipsilesional limb. We hypothesized that mechanisms that bind personal and peripersonal representations would improve these patients' awareness of being touched on their contralesional limbs. Visual--tactile integration and intentional movements were considered candidate mechanisms. Patients were more likely to be aware of contralesional touch when looking towards their contralesional limb than when looking towards their ipsilesional limb, and when actively moving on tactile probes than when receiving tactile stimuli passively. The improved awareness of being touched on the contralesional limb under these conditions suggests that cross-sensory and sensorimotor integration help bind personal and peripersonal space.
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Affiliation(s)
- S Vaishnavi
- University of Pennsylvania, Philadelphia, 19104, USA
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Abstract
Extinction is thought to be due to a pathologically limited attentional capacity in which multiple stimuli cannot be processed simultaneously to conscious awareness. Patients with tactile extinction are aware of being touched on a contralesional limb, but seem unaware of similar contralesional touch if touched simultaneously on their ipsilesional limb. The ipsilesional stimulus interferes and competes with the processing of the contralesional stimulus. Most theorists assume that the ipsilesional stimulus affects the sensory processing of the contralesional stimulus, although the precise functional level at which this interference occurs is not clear. We report a series of experiments using signal detection analyses to investigate tactile extinction in one patient (DC). These analyses revealed that ipsilesional stimuli, in addition to interfering with processing of contralateral sensations, also interfere with verbal reports of those sensations. This influence on responses suggests that interference in tactile extinction can occur at a post-perceptual level, further 'downstream' than previously thought.
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Affiliation(s)
- S Vaishnavi
- Department of Neurology and Center for Cognitive Neuroscience, the University of Pennsylvania, Philadelphia 19104-4283, USA
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Abstract
We investigated tactile awareness in three patients with tactile extinction of stimuli located on contralesional somatotopic space. Contralesional tactile awareness was enhanced when they gazed to the left and when they moved their limbs. We suggest that personal somatotopic and peripersonal space are integrated by polymodal and sensorimotor links, which allow us to be aware of and act effectively on stimuli in space.
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Affiliation(s)
- S Vaishnavi
- Department of Neurology, University of Alabama at Birmingham, USA
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Simon TJ, Vaishnavi S. Subitizing and counting depend on different attentional mechanisms: evidence from visual enumeration in afterimages. Percept Psychophys 1996; 58:915-26. [PMID: 8768186 DOI: 10.3758/bf03205493] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Two experiments showed that, when selective eye movements were disabled by the presentation of stimuli in the form of afterimages, increased inspection time and facilitative stimulus configurations failed to increase the subitizing limit of 4 objects. Afterimages of two to eight dots induced by a photographic flashgun were shown to 3 adult subjects. For more than 4 objects, enumeration errors occurred at a rate of 20%-30%. Enumeration was effectively perfect for 2-4 linearly configured dots, with occasional errors surprisingly occurring in that range when dots appeared in groups of up to 3 items. No errors occurred in nonafterimage control conditions. Enumeration errors were attributed to failures of individuating dots to be counted due to the deactivation of selective eye movements in afterimages. A third experiment supported this interpretation by disabling eye movements with briefly presented stimuli and producing results much like those of the afterimage conditions.
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Affiliation(s)
- T J Simon
- School of Psychology, Georgia Institute of Technology, Atlanta 30332-0170, USA.
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