Fungal Community Composition and Function Associated with Loose Smokeless Tobacco Products

Smokeless tobacco products (STPs) contain several microbial communities which are responsible for the formation of carcinogens, like tobacco-specific nitrosamine (TSNAs). A majority of STPs are sold in loose/unpackaged form which can be loaded with a diverse microbial population. Here, the fungal population and mycotoxins level of three popular Indian loose STPs, Dohra, Mainpuri Kapoori (MK), and loose leaf-chewing tobacco (LCT) was examined using metagenomic sequencing of ITS1 DNA segment of the fungal genome and LC-MS/MS, respectively. We observed that Ascomycota was the most abundant phylum and Sterigmatomyces and Pichia were the predominant fungal genera in loose STPs. MK displayed the highest α-diversity being enriched with pathogenic fungi Apiotrichum, Aspergillus, Candida, Fusarium, Trichosporon, and Wallemia. Further, FUNGuild analysis revealed an abundance of saprotrophs in MK, while pathogen-saprotroph-symbiotroph were abundant in Dohra and LCT. The level of a fungal toxin (ochratoxins A) was high in the MK product. This study caution that loose STPs harbor various harmful fungi that can infect their users and deliver fungal toxins or disrupt the oral microbiome of SLT users which can contribute to several oral pathologies.

"Is Omicron mild"? Testing this narrative with the mutational landscape of its three lineages and response to existing vaccines and therapeutic antibodies

SARS-CoV-2 Omicron with its lineages BA.1, BA.2, and BA.3 has triggered a fresh wave of Covid-19 infections. Though, Omicron has, so far, produced mild symptoms, its genome contains 60 mutations including 37 in the spike protein and 15 in the receptor-binding domain. Thirteen sites conserved in previous SARS-CoV-2 variants carry mutations in Omicron. Many mutations have shown evolution under positive selection. Omicron's giant mutational leap has raised concerns as there are signs of higher virus infectivity rate, pathogenesis, reinfection, and immune evasion. Preliminary studies have reported waning of immunity after two-dose primary vaccine regime, need for the boosters, folds reduction in vaccine effectiveness and neutralizing antibodies even after boosting and significant neutralization resistance with the therapeutic monoclonal, polyclonal, and convalescent antibodies against Omicron. The narrative that "Omicron is mild," therefore, needs time to be tested with a deeper, scientific dwelling into the facts.

Impact of smokeless tobacco-associated bacteriome in oral carcinogenesis

Smokeless tobacco products possess a complex community of microorganisms. The microbial community ferment compounds present in the smokeless tobacco products and convert them into carcinogens like tobacco-associated nitrosamines. However, the potential of smokeless tobacco products associated bacteriome to manipulate systemic inflammation and other signaling pathways involved in the etiology of oral cancer will be a risk factor for oral cancer. Further, damage to oral epithelial cells causes a leaky oral layer that leads to increased infiltration of bacterial components like lipopolysaccharide, flagellin, and toxins, etc. The consumption of smokeless tobacco products can cause damage to the oral layer and dysbiosis of oral microbiota. Hence, the enrichment of harmful microbes due to dysbiosis in the oral cavity can produce high levels of bacterial metabolites and provoke inflammation as well as carcinogenesis. Understanding the complex and dynamic interrelation between the smokeless tobacco-linked bacteriome and host oral microbiome may help to unravel the mechanism of oral carcinogenesis stimulated by smokeless tobacco products. This review provides an insight into smokeless tobacco product-associated bacteriome and their potential in the progression of oral cancer. In the future, this will guide in the evolution of prevention and treatment strategies against smokeless tobacco products-induced oral cancer. Besides, it will assist the government organizations for better management and cessation policy building for the worldwide problem of smokeless tobacco addiction.

UPLC-DAD Assisted Phytochemical Quantitation Reveals a Sex, Ploidy and Ecogeography Specificity in the Expression Levels of Selected Secondary Metabolites in Medicinal Tinospora cordifolia: Implications for Elites' Identification Program

BACKGROUND

Medicinal phytochemistry involving UPLC-DAD in an exhaustive analysis involving quantification of eight commercially important phytochemicals viz. syringin, cordifolioside A, magnoflorine, tinocordiside, palmatine, 20β-hydroxyecdysone, L-tetrahydropalmatine and berberine has been done in 143 accessions from eight states and the union territories of Delhi and Jammu & Kashmir of India representing three different ploidy levels viz. diploid (2x), triploid (3x) and synthetic tetraploid (4x). The study was done to assess the effect of sex, ploidy level and ecogeography on the expression level of secondary metabolites in stems of dioecious, medicinally important shrub Tinospora cordifolia.

METHODS

Two different UPLC-DAD methods were used for the quantification of eight selected phytochemicals from the alcoholic stem extracts of T. cordifolia accessions. The Waters Acquity UPLC system hyphenated to the QTOF micromass system, equipped with PDA and ESI-Q-TOF detectors was utilized for the quantitative analysis, Mass Lynx v 4.0 software was used for data analysis.

RESULTS

Significant quantitative changes were observed in the analysed secondary metabolites among different accessions of T. cordifolia. The triploid (3x) cytotypes revealed higher amounts of seven out of eight analysed secondary metabolites than diploids and only 20β-hydroxyecdysone was observed to be present in significantly higher amount in diploid cytotypes. Further, at the tetraploid level, novel induced colchiploid (synthetic 4x) genotypes revealed increase in the yield of all of the analysed eight phytochemicals than their respective diploid counterparts. The quantity of active principles in tetraploid cytotypes were also higher than the average triploid levels at multiple locations in five out of eight tested phytochemicals, indicating the influence of ploidy on expression levels of secondary metabolites in T. cordifolia. Additionally, at each of the three ploidy levels (2x, 3x and synthetic 4x), a significant sex specificity could be observed in the expression levels of active principles, with female sex outperforming the male in the content of some phytochemicals, while others getting overexpressed in the male sex. The manifestation of diverse ecogeographies on secondary metabolism was observed in the form of identification of high yielding accessions from the states of Madhya Pradesh, Delhi and Himachal Pradesh and the Union territory of Jammu & Kashmir. Two triploid female accessions that contained approximately two- to eight fold higher amounts of five out of the eight analysed phytochemicals have been identified as superior elites from the wild from the states of Delhi and Madhya Pradesh.

CONCLUSION

The paper shows the first observations of ploidy specificity along with subtle sex and ecogeography influence on the expression levels of secondary metabolome in T. cordifolia.

Induction and evaluation of colchitetraploids of two species of Tinospora Miers, 1851

Autotetraploidy, both natural and/or induced, has potential for genetic improvement of various crop species including that of medicinal importance. Tinospora cordifolia (Willdenow, 1806) Miers, 1851 ex Hooker et Thomson, 1855 and T. sinensis (Loureiro, 1790) Merrill, 1934 are two diploid species, which are dioecious, deciduous and climbing shrubs with high medicinal importance. Among the three methods used for induction of polyploidy by colchicine treatment, it was cotton swab method which successfully induced the polyploidy in both species. The morphological and cytogenetical features of the synthetic tetraploids were compared with their diploid counterparts. The tetraploids were morphologically distinct from diploid plants. They exhibited larger organs, such as stem, leaves, inflorescence, fruits, flowers and seeds. The tetraploids were characterized by the presence of low quadrivalent frequency and high bivalent average. Unequal distribution of chromosomes at anaphase I was found in 60% cells. The present study provides important information on the superiority of autotetraploids as compared to diploid counterparts in both species.

Bovine glycomacropeptide promotes the growth of Bifidobacterium longum ssp. infantis and modulates its gene expression

Bovine milk glycomacropeptide (GMP) is derived from κ-casein, with exclusively o-linked glycosylation. Glycomacropeptide promoted the growth of Bifidobacterium longum ssp. infantis in a concentration-dependent manner, and this activity was lost following periodate treatment of the GMP (GMP-P), which disables biological recognition of the conjugated oligosaccharides. Transcriptional analysis of B. longum ssp. infantis following exposure to GMP revealed a substantial response to GMP relative to bacteria treated with GMP-P, with a greater number of differentially expressed transcripts and larger fold changes versus the control. Therefore, stimulation of B. longum ssp. infantis growth by GMP is intrinsically linked to the peptide's O-linked glycosylation. The pool of differentially expressed transcripts included 2 glycoside hydrolase (family 25) genes, which were substantially upregulated following exposure to GMP, but not GMP-P. These GH25 genes were present in duplicated genomic islands that also contained genes encoding fibronectin type III binding domain proteins and numerous phage-related proteins, all of which were also upregulated. Homologs of this genomic arrangement were present in other Bifidobacterium species, which suggest it may be a conserved domain for the utilization of glycosylated peptides. This study provides insights into the molecular basis for the prebiotic effect of bovine milk GMP on B. longum ssp. infantis.

Menopausal Health Status of Nepalese Women

INTRODUCTION

Menopause is an unavoidable and sometimes problematic condition in which women may suffer from a number of health problems. Knowledge of the major symptoms associated with menopause helps reduce the burden and stress associated with the condition. In this context, a study was conducted to establish baseline data regarding menopausal health problems among Nepalese women.

METHODS

A descriptive cross-sectional study was conducted among 2000 women aged over 40 years to identify their knowledge, attitude and practice related to menopausal health problems. Data was collected by interviewing the women and doing physical examination. Analysis was done using descriptive statistics and SPSS software was used for data analysis.

RESULTS

A cohort of 2073 women (ages 40-60 years) participated in the research, among them 2000 yielded complete response. The study revealed that 820 (41%) women had reached menopause. The average age of menopause was 48.7 years. Majority of the women 1183 (59.2%) in the study did not know about menopausal health problems. Abnormal bleeding 353 (17.65%), sweating 315 (15.75%), hot flushes 299 (14.95%), joint/muscle pain 285 (14.25%) were the most common menopausal symptoms known by the women. Joint pain 736 (36.8%), hot flushes 584 (29.2%), irregular bleeding 582 (29.1%) were the most common experienced symptoms of menopause and only 586 (29.3%) consulted the health workers to alleviate menopausal symptoms. Moreover, most of the women 926 (46.3%) accepted menopause as a part of life.

CONCLUSIONS

The research has tried to establish the baseline of menopausal health problems in the Nepalese women. The average age of menopause was 48.7 years. Majority did not know about menopausal health problems. Further researches with nationally representative sample are recommended to further explore the menopausal health problems of Nepalese women.

Uterus Didelphys with Pregnancy

We report a case of 21 Yrs old female patient referred to the radiology department at Shree Birndra Hospital, to investigate primary infertility. She underwent hysterosalpingogram, both transabdominal & transvaginal ultrasound and MRI of the pelvis. The final diagnosis was Uterus Didelphys, which is a type of lateral fusion disorder of mullerian ducts. According to the American Fertility Society Classification of Mullerian Anomalies, Uterus Didelphys is a class III anomaly. DOI: http://dx.doi.org/10.3126/mjsbh.v10i1.6449 Medical Journal of Shree Birendra Hospital Jan-June 2011 10(1) 40-43

Sweet-talk: role of host glycosylation in bacterial pathogenesis of the gastrointestinal tract

Glycosylation is a key modification of proteins and lipids and is involved in most intermolecular and intercellular interactions. The gastrointestinal mucus gel is continuous and can be divided into two layers: a secreted loosely associated layer and a layer firmly attached to the mucosa. In addition, the membrane-bound glycosylated proteins and lipids create a glycocalyx, which remains adherent on each cell and is dynamic and responsive to the physiological state and environment of the cell. The secreted glycans form a mucus gel layer that serves as a physicochemical sensor and barrier network and is primarily composed of mucins and associated peptides. These glycans protect gut epithelial cells from chemical, biological and physical insults and are continuously renewed. Pathogens colonise and invade the host epithelial cells using protein-protein and glycan-lectin interactions. During the process of colonisation and infection, the glycosylation state of both host and pathogen change in response to the presence of the other. This complex modulation of glycan expression critically determines pathogenesis and the host response in terms of structural changes and immune response. In addition, by influencing host immunity and gut glycosylation, the microbiota can further effect protection against pathogens. In this review, the roles of host glycosylation in interactions with two prevalent bacterial pathogens, Campylobater jejuni and Helicobacter pylori, are discussed to illustrate important concepts in pathogenesis.

Performance in the Duke-Elder ophthalmology undergraduate prize examination and future careers in ophthalmology

AIMS

Cognitive factors (eg, academic achievement) have had a significant role in selecting postgraduate surgical trainees in the past. This project sought to determine the role of a national undergraduate ophthalmology prize examination (Duke-Elder examination) in the selection of postgraduate ophthalmology trainees. This would also serve as a quality assurance exercise for the assessment, in which the ultimate aim is to encourage trainees into ophthalmology.

METHODS

A retrospective analysis of the top 20 ranked candidates in the Duke-Elder examination from 1989 to 2005 (except 1995) was carried out to determine which of them subsequently entered the ophthalmic training and General Medical Council Specialist Registers.

RESULTS

Out of the top 20 candidates in the exam, 29.5% went into specialist training in ophthalmology. Some appeared in the top 20 more than once, with 56% of them going into ophthalmic training, but they had a similar median time to enter training as those who appeared in the top 20 once. There was no significant evidence to suggest that the overall median ranking scores between the UK medical schools differed (P=0.23; Kruskal-Wallis test). However, there was a marked difference in frequency of top 20 candidates from each medical school, which could not be explained by the size of the medical school alone.

CONCLUSION

It is difficult to conclude from these findings the importance that the Duke-Elder examination has in the selection of trainees into ophthalmology. The role of cognitive factors in selection into postgraduate medical/surgical training is discussed, along with the potential academic criteria, which may influence interview scores.

Biocombinatorial selection of carbohydrate binding agents of therapeutic significance

Components of the cell-surface and extracellular matrix (including cell walls of some microorganisms) present ideal but often challenging targets for disease detection and targeting. In the past few years, selection of peptide and oligonucleotide biomimics against secreted and extracellular targets has resulted in the isolation of small high affinity binding agents against target molecules. However, little attention has been paid to the interaction of these biomimics with glycans (specifically, cell surface glycans) despite their ubiquitous and abundant presence on every cell (glycocalyx). Although glycans are now accepted as critically important class of molecules as biomarkers, imaging, therapeutic and drug targets, little advance has been made in exploiting these molecules for clinical applications. The diversity and complexity of glycan structures along with time-consuming analytical and synthetic methods are among the most significant challenges faced by glycoscientists. Innovative technologies are urgently needed to overcome these challenges and to develop glycan-based clinical applications. This review article will provide an overview of existing biocombinatorial methods that focus on the selection and use of glycan-binding random oligonucleotide ligands (aptamers) as conceptually novel therapeutics for a variety of biomedical applications including anti-microbial and anti-cancer agents. Given the range and importance of protein-carbohydrate interactions in biological processes, rapid discovery of agents that mediate these interactions may provide fruitful venues towards novel therapeutics.

Space flight alters bacterial gene expression and virulence and reveals a role for global regulator Hfq

A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the space flight environment has never been accomplished because of significant technological and logistical hurdles. Moreover, the effects of space flight on microbial pathogenicity and associated infectious disease risks have not been studied. The bacterial pathogen Salmonella typhimurium was grown aboard Space Shuttle mission STS-115 and compared with identical ground control cultures. Global microarray and proteomic analyses revealed that 167 transcripts and 73 proteins changed expression with the conserved RNA-binding protein Hfq identified as a likely global regulator involved in the response to this environment. Hfq involvement was confirmed with a ground-based microgravity culture model. Space flight samples exhibited enhanced virulence in a murine infection model and extracellular matrix accumulation consistent with a biofilm. Strategies to target Hfq and related regulators could potentially decrease infectious disease risks during space flight missions and provide novel therapeutic options on Earth.

Synthesis, purification and structural and functional characterization of recombinant form of a common genetic variant of human luteinizing hormone

A common genetic variant (V) of luteinizing hormone (LH), with two mutations (Trp(8)Arg and Ile(15)Thr) and an extra glycosylation consensus site (Asn(13)-Ala-Thr), is associated with abnormalities of reproductive function. To address the molecular basis of the functional differences between V- and wild-type (WT)-LH, recombinant (rec) forms of WT- and V-LH were synthesized in human embryonic kidney (HEK 293) cells. The rec hormones synthesized were rigorously purified employing affinity, immunoaffinity and ion exchange chromatographies (final purity approximately 12 000 IU/mg, 180-fold purification, 28% recovery). Functional properties of the hormone preparations were compared in vitro and in vivo. The molecular size of both rec LHs was 31 kDa, as determined by SDS-PAGE. Although the mutations in V-LHbeta did not significantly affect the affinity of LH receptor (LHR) binding (Kd approximately 0.4 nmol/L), V-LH had higher in vitro biopotency than WT-LH, in terms of mLTC-1 mouse Leydig tumor cell cAMP and progesterone (P) production, and steroidogenic acute regulatory protein (StAR) expression. In addition, in HEK 293 cells expressing the human LHR, V-LH demonstrated 1.8-fold higher response of inositol trisphosphate (IP(3)) production than WT-LH. Furthermore, HEK 293 cells expressing the ElK1 trans-reporting plasmids displayed 2.7-fold greater luciferase response to V-LH than WT-LH, documenting stimulation of the mitogen-activated protein kinase (MAPK) pathway. The in vivo half-life of V-LH was clearly faster (5-9 min) than that of WT-LH (12-22 min) and human chorionic gonadotropin (hCG; 50-70 min), when injected into rat circulation. It is worth noting that analysis by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) demonstrated clear differences in structures of carbohydrate side chains attached to the two forms of rec LHs, including incomplete processing of high mannose glycans (Man(5,8,9)) in V-LH, suggesting different pathways in its intracellular trafficking. Collectively, the present findings provide the molecular basis for the qualitative and quantitative differences in LH action that are observed in carriers of the V-LHbeta allele.

Successful establishment of long-term bone marrow cultures in 103 patients with myelodysplastic syndromes

We used bone marrow biopsies instead of mononuclear cells to maintain long-term cultures from 103 patients belonging to all five sub-categories of myelodysplastic syndromes (MDS), as well as 12 normal controls. By week 4, 30-50% confluency was reached and could be maintained for up to 12 weeks with 100% confluency. The four prominent cells were fibroblasts, macrophages, endothelial cells and adipocytes. Immunohistochemical and electron microscopic studies provided lineage confirmation. Normal hematopoiesis was well supported by MDS stroma. Neither the FAB nor cytogenetics was co-related with the potency of growth. MDS stroma appears to be both morphologically and functionally normal.

Production of a sialylated N-linked glycoprotein in insect cells

Under High Aspect Ratio Vessel (HARV) bioreactor culture conditions designed to simulate the microgravity of orbital space flight, insect tissue culture cells infected with a baculovirus expression vector produced a human glycoprotein with tri- and tetra-antennary complex N-linked oligosaccharides containing terminal sialic acid residues. The oligosaccharide structures were similar to those produced in human placental cells. Insect cells cultured in T-flasks only performed incomplete oligosaccharide processing. The mechanism of HARV-mediated changes in the eukaryotic N-linked glycosylation pathway was investigated and could be mimicked under T-flask growth conditions with the addition of N-acetylmannosamine to the culture medium. The significance of these investigations is discussed with respect to the production of recombinant therapeutic glycoproteins, insect physiology, and orbital space flight.

Characterization of glycosylated variants of beta-lactoglobulin expressed in Pichia pastoris

Glycosylated variants of beta-lactoglobulin (BLG) were produced in the methylotrophic yeast Pichia pastoris to mimic the glycosylation pattern of glycodelin, a homologue of BLG found in humans. Glycodelin has three sites for glycosylation, corresponding to amino acids 63-65 (S1), 85-87 (S2) and 28-30 (S3) of BLG. These three sites were engineered into BLG to produce the variants S2, S12 and S123, which carried one, two and three glycosylation sites, respectively. The oligosaccharides on these BLG variants ranged from (mannose)(9)(N-acetylglucosamine)(2) (Man(9)GN(2)) to Man(15)GN(2) and were of the alpha-linked high mannose type. The variant S123 exhibited highest levels of glycosylation, with the range of glycans being Man(9-14)GN(2). Digestion of S123 with alpha-1,2 linkage specific mannosidase resulted in a single product corresponding to Man(6)GN(2). These results indicated a glycosylation pattern consisting of a Man(5)GN(2) structure extended by 4-9 mannose residues attached mainly by alpha-1,2 linkages. The results also indicated extension of the Man(5)GN(2) structure by a single alpha-1,6-linked mannose. The N-linked glycosylation pathway in P.pastoris is significantly different from that in Saccharomyces cerevisiae, with the addition of shorter outer chains to the core and no alpha-1,3 outer extensions.

Influence of baculovirus-host cell interactions on complex N-linked glycosylation of a recombinant human protein

The conditions required for mammalian-type complex N-linked glycosylation of human proteins produced in insect cells with the baculovirus expression vector system were investigated. Marked alterations to N-linked glycosylation of human placental secreted alkaline phosphatase (SEAP) were observed with different baculovirus species, insect cell lines, and cell culture media. When a recombinant Autographa californica nucleopolyhedrovirus (AcMNPV) was used to produce SEAP in Trichoplusia ni (Tn-4h) cells cultured in serum-free medium, structural analyses indicated <1% hybrid and no complex oligosaccharides attached to SEAP, a typical result with the baculovirus expression vector system. However, when fetal bovine serum was added to the culture medium, 48 +/- 4% of the oligosaccharides were hybrid or complex (but asialylated) glycans. When a recombinant T. ni nucleopolyhedrovirus (TnSNPV) was similarly used to express SEAP in Tn-4h cells cultured in serum-containing medium, only 24 +/- 3% of the glycans contained terminal N-acetylglucosamine and/or galactose residues. In contrast, SEAP produced in Sf9 cells grown in serum-containing medium with AcMNPV contained <1% hybrid oligosaccharides and no complex oligosaccharides. The results illustrate that baculovirus type, host cell type, and the growth medium all have a strong influence on the glycosylation pathway in insect cells, resulting in significant alterations in structures and relative abundance of N-linked glycoforms. Although the addition of sialic acid residues to the SEAP glycans was not detected, possible approaches to obtain sialylated glycans are discussed.

Genital Prolapse With Traumatic Vesicovaginal Fistula

Genital Prolapse With Traumatic Vesicovaginal Fistula

Cloning, expression, and substrate specificity of MeCPA, a zinc carboxypeptidase that is secreted into infected tissues by the fungal entomopathogen Metarhizium anisopliae

To date zinc carboxypeptidases have only been found in animals and actinomycete bacteria. A cDNA clone (MeCPA) for a novel fungal (Metarhizium anisopliae) carboxypeptidase (MeCPA) was obtained by using reverse transcription differential display polymerase chain reaction to identify pathogenicity genes. MeCPA resembles pancreatic carboxypeptidases in being synthesized as a precursor species (418 amino acids) containing a large amino-terminal fragment (99 amino acids). The mature (secreted) form of MeCPA shows closest amino acid identity to human carboxypeptidases A1 (35%) and A2 (37%). MeCPA was expressed in an insect cell line yielding an enzyme with dual A1 + A2 specificity for branched aliphatic and aromatic COOH-terminal amino acids. However, in contrast to the very broad spectrum A + B-type bacterial enzymes, MeCPA lacks B-type activity against charged amino acids. This is predictable as key catalytic residues determining the specificity of MeCPA are conserved with those of mammalian A-type carboxypeptidases. Thus, in evolutionary terms the fungal enzyme is an intermediate between the divergence of A and B forms and the differentiation of the A form into A1 and A2 isoforms. Ultrastructural immunocytochemistry of infected host (Manduca sexta) cuticle demonstrated that MeCPA participates with the concurrently produced endoproteases in procuring nutrients; an equivalent function to digestive pancreatic enzymes.

Ambient pH is a major determinant in the expression of cuticle-degrading enzymes and hydrophobin by Metarhizium anisopliae

Secretion of proteolytic and chitinolytic enzymes is a hallmark of infection processes of Metralhizium anisopliae in response to host (insect) cuticular signals. The regulation of these enzymes (subtilisin-like proteases [Pr1a and Pr1b], trypsin-like proteases [Pr2], metalloproteases, aspartyl proteases, aminopeptidase, and chitinases) and a hydrophobin was investigated by Northern analysis and/or enzyme assay. The production of each enzyme showed a differential expression pattern in response to ambient pH; enzymes were synthesized only at pHs at which they function effectively, irrespective of whether the medium contained an inductive cuticle substrate. Three aspartyl proteases (pH optimum, 3), and chitinase (pH optimum, 5) showed maximal accumulation at acidic pHs. The highest level of aminopeptidase (pH optimum, 7) was detected at pH 7. The highest levels of five metalloproteases (pH optima, ca. 7) were detected over the pH range 6 to 8. Two trypsins and several subtilisin-like Pr1 isoforms with pH optima of ca. 8 were produced only under alkaline conditions. Northern analysis of RNA species corresponding to seven cDNA sequences encoding proteases and chitinase confirmed that the ambient pH played a major role in gene expression of secreted proteins. Hydrophobin was expressed almost equally at pHs 5 and 8 but was not expressed at pH 3. During fungal penetration, the pH of infected cuticle rises from about 6.3 to 7.7. Consistent with pH regulation of enzyme production, serine and metalloproteases were produced in situ during infection, but no production of aspartyl proteases was found. We propose that the alkalinity of infected cuticle represents a physiological signal that triggers the production of virulence factors.

Isolation of a cDNA encoding a novel subtilisin-like protease (Pr1B) from the entomopathogenic fungus, Metarhizium anisopliae using differential display-RT-PCR

Reverse transcription differential display PCR (RT-DD-PCR) was used to identify genes that are specifically expressed by Metarhizium anisopliae when it contacts the host insect cuticle. Using a homology-based subtilisin-like protease primer we identified a hitherto unsuspected differentially expressed subtilisin-like protease (Pr1B) encoding gene. The deduced amino acid sequence shows 54% similarity to the well characterized Pr1A subtilisin of M. anisopliae and karyotype analysis revealed that Pr1A and Pr1B are located on separate chromosomes. Like Pr1A, Pr1B is synthesized as a large precursor (1158 nucleotides; deduced molecular mass = 40031 Da) containing a signal peptide, a propeptide and the mature protease (283 aa; deduced molecular mass = 28714 Da). However, Pr1B possesses several substitutions in the highly conserved sequences comprising the active sites of subtilisins. In particular, the substitution of Thr220 by serine is unique to Pr1B. Substitution of Asn155 by glycine is also very unusual, and we discuss the likely effects these changes will have on the catalytic efficiency of Pr1B.

Construction of an improved mycoinsecticide overexpressing a toxic protease

Mycoinsecticides are being used for the control of many insect pests as an environmentally acceptable alternative to chemical insecticides. A key aim of much recent work has been to increase the speed of kill and so improve commercial efficacy of these biocontrol agents. This might he achieved by adding insecticidal genes to the fungus, an approach considered to have enormous potential for the improvement of biological pesticides. We report here the development of a genetically improved entomopathogenic fungus. Additional copies of the gene encoding a regulated cuticle-degrading protease (Pr1) from Metarhizium anisopliae were inserted into the genome of M. anisopliae such that Pr1 was constitutively overproduced in the hemolymph of Manduca sexta, activating the prophenoloxidase system. The combined toxic effects of Pr1 and the reaction products of phenoloxidase caused larvae challenged with the engineered fungus to exhibit a 25% reduction in time of death and reduced food consumption by 40% compared to infections by the wild-type fungus. In addition, infected insects were rapidly melanized, and the resulting cadavers were poor substrates for fungal sporulation. Thus, environmental persistence of the genetically engineered fungus is reduced, thereby providing biological containment.

Biochemical characterization and ultrastructural localization of two extracellular trypsins produced by Metarhizium anisopliae in infected insect cuticles

Proteinase 2 (Pr2) is a fungal (Metarhizium anisopliae) serine proteinase which has a tryptic specificity for basic residues and which may be involved in entomopathogenicity. Analytical and preparative isoelectric focusing methods were used to separate two trypsin components, produced during growth on cockroach cuticle, with isoelectric points of 4.4 (molecular mass, 30 kDa) and 4.9 (27 kDa). The catalytic properties of the proteases were analyzed by their kinetic constants and by a combination of two-dimensional gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzyme overlay membranes. Both Pr2 isoforms preferentially cleave at the carboxyl sides of positively charged amino acids, preferring arginine; the pI 4.4 Pr2 isoform also possessed significant activity against lysine. Compared with the pathogen's subtilisin-like enzyme (Pr1), the pI 4.4 Pr2 isoform shows low activity against insoluble proteins in a host (Manduca sexta) cuticle. However, it degrades most cuticle proteins when they are solubilized, with high-molecular-weight basic proteins being preferentially hydrolyzed. Polyclonal antibodies raised against each Pr2 isoform were isotype specific. This allowed us to use ultrastructural immunocytochemistry to independently visualize each isoform during penetration of the host (M. sexta) cuticle. Both isoforms were secreted by infection structures (appressoria) on the cuticle surface and by the penetrant hyphae within the cuticle. The extracellular sheath, which is commonly observed around fungal cells, often contained Pr2 molecules. Intracellular labelling was sparse.

Characterization and Ultrastructural Localization of Chitinases from Metarhizium anisopliae, M. flavoviride, and Beauveria bassiana during Fungal Invasion of Host (Manduca sexta) Cuticle

Extracellular chitinases have been suggested to be virulence factors in fungal entomopathogenicity. We employed isoelectric focusing and a set of three fluorescent substrates to investigate the numbers and types of chitinolytic enzymes produced by the entomopathogenic fungi Metarhizium anisopliae, Metarhizium flavoviride, and Beauveria bassiana. Each species produced a variety of N-acetyl-(beta)-d-glucosaminidases and endochitinases during growth in media containing insect cuticle. M. flavoviride also produced 1,4-(beta)-chitobiosidases. The endochitinases could be divided according to whether they had basic or acidic isoelectric points. In contrast to those of the other two species, the predominant endochitinases of M. anisopliae were acidic, with isoelectric points of about 4.8. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved the acidic chitinases of M. anisopliae into two major bands (43.5 and 45 kDa) with identical N-terminal sequences (AGGYVNAVYFY TNGLYLSNYQPA) similar to an endochitinase from the mycoparasite Trichoderma harzianum. Use of polyclonal antibodies to the 45-kDa isoform and ultrastructural immunocytochemistry enabled us to visualize chitinase production during penetration of the host (Manduca sexta) cuticle. Chitinase was produced at very low levels by infection structures on the cuticle surface and during the initial penetration of the cuticle, but much greater levels of chitinase accumulated in zones of proteolytic degradation, which suggests that the release of the chitinase is dependent on the accessibility of its substrate.

Recombinant thyrotropin containing a beta-subunit chimera with the human chorionic gonadotropin-beta carboxy-terminus is biologically active, with a prolonged plasma half-life: role of carbohydrate in bioactivity and metabolic clearance

Recombinant TSH is now successfully being used in clinical studies of thyroid cancer. Because of its therapeutic potential, we have constructed a longer acting analog of TSH by fusing the carboxy-terminal extension peptide (CTEP) of hCG beta onto TSH beta. When coexpressed either with alpha-subunit complementary DNA or alpha minigene in African green monkey (COS-7) and human embryonic kidney (293) cells, the chimera was fully bioactive in vitro and exhibited enhanced in vivo potency associated with a prolonged plasma half-life. The addition of 25 amino acids with 4 O-linked oligosaccharide chains did not affect the assembly and secretion of chimeric TSH. Wild-type (WT) and chimeric TSH secreted by COS-7 and 293 cells displayed wide differences in their plasma half-lives, presumably due to the presence of terminal sialic acid and SO4 on their oligosaccharide chains, respectively. Chimeric and WT TSH secreted by both cell lines demonstrated similar bioactivity in cAMP production, with some differences in [3H]thymidine incorporation. Chimeric TSH appears to be more effective in COS-7 cells than in 293 cells, as judged by growth assay. COS-7-produced chimeric TSH showed the maximum increase in half-life, indicating the importance of sialic acid in prolonging half-life and in vivo potency. Sulfation of both subunits, predominantly beta and to a lesser extent alpha, appears to be responsible at least in part for the increased metabolic clearance of WT and chimeric TSH secreted by 293 cells. Apart from its therapeutic potential, chimeric TSH produced in various cell lines can be used as a tool to delineate the roles of sulfate and sialic acid in the in vivo clearance and, thereby, the in vivo bioactivity.

Cloning of a cuticle-degrading protease from the entomopathogenic fungus, Beauveria bassiana

A Beauveria bassiana extracellular subtilisin-like serine endoprotease is a potential virulence factor by virtue of its activity against insect cuticles. A cDNA clone of the protease was isolated from mycelia of B. bassiana grown on cuticle/chitin cultures. The amino acid sequence of this gene was compared to that of Metarhizium anisopliae Pr1, the only pathogenicity determinant so far described from an entomopathogenic fungus, and proteinase K, isolated from Tritirachium album, a saprophytic fungus. The cDNA sequence revealed that B. bassiana Pr1 is synthesized as a large precursor (M(r) 37,460) containing a signal peptide, a propeptide and the mature protein predicted to have an M(r) of 26,832.

Studies on the lactose character in Salmonella S:41:z10

A number of plasmids carrying the Lac+ character have been reported. Lac+ character of salmonella S:41:z10:- studied for transfer of Lac+ character to standard Escherichia coli K12 Lac-F- Nalr and Escherichia coli K12 F- Lac- Rifr, failed to transfer in in vitro experiments. Similarly, identification and characterisation of plasmid DNA by agarose gel electrophoresis technique did not show specific plasmid DNA as compared to standard molecular weight plasmids. Plasmid DNA appeared to have been embedded with chromosomal DNA molecule.

ELISA--its evaluation in diagnosis of tuberculosis meningitis

Diagnostic utility of an enzyme linked immunosorbent assay (ELISA) in hospitalised patients with clinical symptoms suggestive of tuberculous meningitis (94 cases) was studied. CSF Anti-tubercular IgG antibody levels were estimated by ELISA in 44 cases of proven tuberculous meningitis, 24 proven pyogenic meningitis and in 48 non-tuberculous cases. The cut off dilution was established at a CSF dilution of 1 : 1 (undiluted) with positive and negative controls. The ELISA test had a sensitivity of 97.72% and a specificity of 95.35% using MSE antigen. When compared with conventional smear examination and culture isolation from specimens, the ELISA test proved statistically superior in the detection rate or diagnosis of clinically suspected tuberculous meningitis cases (P less than 0.05).

Interaction of EDTA with tributyltin induced cellular toxicity

Tributyltin inhibited the growth of cells in concentration dependent manner. The inhibitory effect of tributyltin on E. coli was enhanced in the presence of metal ion chelator, EDTA. This was due to EDTA induced increase of permeability of bacterial cell envelope to tributyltin. In case of EDTA treated cells the rate of uptake of tributyltin was more pronounced as compared to control.

Demonstration of luteinizing hormone/human chorionic gonadotrophin receptor-binding inhibitor in aqueous extracts of frozen human corpus luteum

Aqueous extracts of frozen human corpora lutea were tested for the presence of an inhibitor of luteinizing hormone-receptor site binding (LHRBI) and for the subsequent effect on the stimulatory response of luteinizing hormone (LH) on progesterone synthesis by sheep ovarian cells. In the presence of human corpus luteum extract of normal menstrual cycle (30,000-g supernatant), the binding of 125I human chorionic gonadotrophin (hCG) to granulosa and luteal cells of sheep ovaries was markedly reduced, but the ability of rat testicular LH receptors to bind labelled hCG was less affected. However, extracts of corpora lutea of the first trimester of pregnancy appeared to be less inhibitory on the binding of LH/hCG to ovarian cells and had no effect on the binding of rat testicular cells compared to those of normal menstrual cycle. Addition of both extracts separately inhibited the LH-stimulated in vitro progesterone synthesis by granulosa cell cultures and by incubated sheep corpus luteum slices. These findings provide evidence for the presence of LHRBI in human corpus luteum.

Effect of contraceptive steroids on human lactation

Biochemical studies to detect changes occurring in the composition of mother's milk from the initiation of proper lactation to weaning were done in a group of 36 postpartum women, volunteers who were either using the conventional contraceptives or taking a low-dose combination pill, a low-dose progestational compound, or a 3 or 6 monthly injection as a mode of contraception. Apart from a significant increase in the protein content of milk and a slight increase in the quantity, the 3 monthly injection group behaved exactly like the control. On the other hand, the 6 monthly injection group showed a significant increase in quantity but with a significant decrease in protein, fats, and calcium. The low-dosage progestogens group showed a significant decrease in the quantity of fats and the calcium content of milk, but, surprisingly, the addition of 10 micrograms of estrogens to the low-dosage progestogen indicated a pattern almost similar to the control.

The effect of centchroman on serum luteinizing hormone in normal males

Elevation of serum luteinizing hormone levels was observed in five normal male volunteers while they were taking Centchroman. This effect resembles that of clomiphene and suggests a new biologic potential of Centchroman.