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Background Laccases and laccase-like multicopper oxidases (LMCOs) oxidize a vast array of phenolic compounds and amines, releasing water as a byproduct. Their low substrate specificity is responsible for their tremendous biotechnological interest, since they have been used for numerous applications. However, the laccases characterized so far correspond to only a small fraction of the laccase genes identified in fungal genomes. Therefore, the knowledge regarding the biochemistry and physiological role of minor laccase-like isoforms is still limited. Results In the present work, we describe the isolation, purification and characterization of two novel LMCOs, PcLac1 and PcLac2, from Pleurotus citrinopileatus. Both LMCOs were purified with ion-exchange chromatographic methods. PcLac2 was found to oxidize a broader substrate range than PcLac1, but both LMCOs showed similar formal potentials, lower than those reported previously for laccases from white-rot fungi. Proteomic analysis of both proteins revealed their similarity with other well-characterized laccases from Pleurotus strains. Both LMCOs were applied to the oxidation of ferulic and sinapic acid, yielding oligomers with possible antioxidant activity. Conclusions Overall, the findings of the present work can offer new insights regarding the biochemistry and variability of low-redox potential laccases of fungal origin. Low-redox potential biocatalysts could offer higher substrate selectivity than their high-redox counterparts, and thus, they could be of applied value in the field of biocatalysis.

Studies were taken up to monitor the seasonal occurrence of whitefly population in cotton as well as its insecticidal management under field conditions of Institutional Research Farm, Institute of Agriculture, Visva-Bharati, Sriniketan, during the kharif season of 2018-19. Population reduction of whitefly was done with eight insecticides having different molecular composition and one untreated check. The experiment was drawn in a Randomised Block Design with three replications. The occurrence of whitefly was noticed during the fourth week of July (0.2 whitefly per plant) which continued till late December. Highest whitefly population was found during fourth week of September (12.24 Whitefly per plant). Correlation studies of whitefly population and abiotic factors suggested that whitefly population was significantly correlated with maximum temperature at 1% level of significance. Among the different insecticides tested for population reduction of whitefly in Bt cotton it was noticed that combination product of Imidacloprid 6% + Lambda Cyhalothrin 4%SL @ 500 ml/ha and 450 ml/ha proved most effective and gave 94.15% and 93.81% pest population reduction after second spray imposition respectively.

Colchicine is a well-known and potent microtubule targeting agent, but the therapeutic value of colchicine against cancer is limited by its toxicity against normal cells. But, there is no report of its cytotoxic potential against lung cancer cell, at clinically permissible or lower concentrations, minimally toxic to non-cancerous cells. Hence, in the present study, we investigated the possible mechanism by which the efficacy of colchicine against lung cancer cells at less toxic dose could be enhanced. Colchicine at clinically admissible concentration of 2.5 nM had no cytotoxic effect and caused no G2/M arrest in A549 cells. However, at this concentration, colchicine strongly hindered the reformation of cold depolymerised interphase and spindle microtubule. Colchicine induced senescence and reactive oxygen species mediated autophagy in A549 cells at this concentration. Autophagy inhibitor 3-methyladenine (3-MA) sensitised the cytotoxicity of colchicine in A549 cells by switching senescence to apoptotic death, and this combination had reduced cytotoxicity to normal lung fibroblast cells (WI38). Together, these findings indicated the possible use of colchicine at clinically relevant dose along with autophagy inhibitor in cancer therapy.

Microtubule-Targeting agents (MTA) are indispensable for cancer therapeutics. We here report thymoquinone (TQ) as a new MTA that already has been appreciated for its anticancer effects. TQ induced G2/M cell cycle arrest in human non-small lung epithelial cells (A549) and majority of arrested cells were in mitosis. TQ depolymerized the microtubule (MT) network and disrupted mitotic spindle organization of A549 cells. MT depolymerization by TQ was followed by apoptosis and subsequent loss in cell viability (IC50 value of ∼10 μM). Interestingly, TQ didn't affect the MT network of normal HUVEC cells at and below the IC50 concentration for A549 cells. TQ also inhibited tubulin polymerization in cell-free system with an IC50 of 27 μM and bound to tubulin heterodimers at a single site with a dissociation constant of 1.19 μM at 25 °C. Binding of TQ to tubulin quenched the tryptophan fluorescence of protein in a time-dependent manner. The TQ-tubulin binding kinetics was biphasic in nature and equilibrated in 30 min. TQ competed with colchicine for tubulin binding with a Ki of 1.9 μM as determined by modified Dixon plot analysis, this suggests TQ may bind tubulin at or near the colchicine binding site and in silico modeling study supported that. Our results establish a novel antimitotic mechanism of TQ by its direct binding to tubulin-MT network in A549 cells.

A live oral cholera vaccine developed from a non-toxigenic Vibrio cholerae O1 El Tor strain VA1.3 was tested in a double-blind randomized placebo controlled study for safety and immunogenicity in 304 men aged between 16 and 50 years from Kolkata, India. A dose of 5 x 10(9)CFU (n=186) or a placebo (n=116) containing the diluent buffer was administered. The vaccine did not elicit adverse events except in two vaccine recipients with mild diarrhoea and vomiting. None excreted the vaccine strain. Vibriocidal antibody response developed in 105/186 (57%) and 5/116 (4%) in vaccine and placebo recipients, respectively. In a subgroup, anti-CT antibody rose (or =2-folds) in 23/30 (77%) and 6/19 (32%) in vaccine and placebo recipients, respectively. These studies demonstrate that VA1.3 at a dose of 5 x 10(9) is safe and immunogenic in adults from a cholera endemic region.

The incidence of Vibrio cholerae non-O1, non-O139 strains from hospitalized patients with acute diarrhea constituted 27.4% ( n = 54) of the total 197 V. cholerae strains isolated from patients in Kolkata, India, in 2003. Of 197 strains, 135 were identified as O1 serotype Ogawa and 2 were identified as O139. In the same time period, six O1 background rough strains that possessed all known virulence factors were identified. Serotype analysis of the non-O1, non-O139 strains placed 42 strains into 19 serogroups, while 12 remained O nontypeable (ONT); the existing serotyping scheme involved antisera to 206 serogroups. Detection of a good number of ONT strains suggested that additional serogroups have arisen that need to be added to the current serotyping scheme. The non-O1, non-O139 strains were nontoxigenic except for an O36 strain (SC124), which regulated expression of cholera toxin as O1 classical strains did. Additionally, strain SC124 carried alleles of tcpA and toxT that were different from those of the O1 counterpart, and these were also found in five clonally related strains belonging to different serogroups. Strains carrying tcpA exhibited higher colonization in an animal model compared to those lacking tcpA . PCR-based analyses revealed remarkable variations in the distribution of other virulence factors, including hlyA , rtxA , Vibrio seventh pandemic island I (VSP-I), VSP-II, and type III secretion system (TTSS). Most strains contained hlyA (87%) and rtxA (81.5%) and secreted cytotoxic factors when grown in vitro. Approximately one-third of the strains (31.5%) contained the TTSS gene cluster, and most of these strains were more motile and hemolytic against rabbit erythrocytes. Partial nucleotide sequence analysis of the TTSS-containing strains revealed silent nucleotide mutations within vcsN2 (type III secretion cytoplasmic ATPase), indicating functional conservation of the TTSS apparatus.

SUMMARY This study reports the analgesic, anti-inflammatory and membrane-stabilizing property of alcoholicextract of Ophiorrhiza nicobarica (ON), a wild herb, used as an anti-infective ethnomedicine ofNicobarese and Shompen tribes of Great Nicobar Island, India. We for the first time investigated theanalgesic and antiinflammatory potential of this herb in acute, subacute and chronic model ofinflammation in Swiss albino mice and Wistar albino rats, along with sheep RBC-induced sensitivityand membrane stabilization. The acetic acid induced writhing, tail flick and tail immersion tests areused as a model for evaluating analgesic activity; while the carrageenin-induced paw oedema wasused as the model for acute inflammation, dextran-induced oedema as sub-acute and cotton-pellate-induced granuloma as chronic inflammatory model. The probable mode by which ON mediate itseffect on inflammatory conditions was studied on sheep RBC-induced sensitivity and membranestabilization. The in vitro results revealed that the ON extract possesses significant (P < 0.05) dosedependent analgesic and antiinflammatory activity at 200 and 300 mg/kg and its fractions at 50 mg/kg, p.o. respectively, compared to the control groups. However, the extract failed to exhibitmembrane-stabilizing property as it unable to reduce the level of haemolysis of RBC exposed tohypotonic solution. The acute toxicity studies of ON extract in rats and mice revealed that the extractwas nontoxic even up to 3.0 g/kg body weight of the animals, with a high safety profile. We haveisolated ursolic acid, β-sitosterol and harmaline respectively, from the bioactive part of the extract. Theresults indicated that the O. nicobarica is indeed beneficial in primary health care, and suggest that itsanti-inflammatory activity may not be related to membrane-stabilization.Key words: Ophiorrhiza nicobarica; Analgesic activity; Anti-inflammatory activity; Membrane-stabilizing property

SUMMARYIn this study, we have analysed the epidemiological significance of the concurrent infections caused by Vibrio cholerae and intestinal parasites among different age groups of hospitalized diarrhoeal patients in Kolkata. A total of 3556 stool samples collected during 1996–2004 were screened for vibrios and parasites. The seasonality of V. cholerae and parasitic infections were studied in detail. The detection rates for Ascaris lumbricoides and Giardia lamblia infection were more than for the hookworm, Trichuris trichiura and Entamoeba histolytica. V. cholerae O1 was identified as the predominant serogroup among diarrhoeal patients. The highest rates for V. cholerae infection were in the 2–5 years age group and combined infection of V. cholerae and parasites was recorded among children aged between 2 and 10 years.

Variations of carbon and oxygen isotopic ratios in response to cyclical sea level fluctuations have been documented from a Paleoproterozoic peritidal stromatolite succession. The upper division of the Kajrahat Limestone, Vindhyan Supergroup of central India consists of several shallowing upward stromatolite cycles identified by regular and systematic changes in stromatolite size. Normally, larger stromatolites are followed upward in the succession by smaller stromatolites and microbial laminites that occupy the top of the cycle. Desiccation cracks are found in all the facies indicating subaerial exposure. We investigated the stable isotope compositional variations across nine complete stromatolite cycles showing frequent subaerial emergence. Carbon and oxygen isotopic values of the limestones, in general, are comparable to contemporary marine values available from earlier studies but show regular depletion in response to shallowing of the water level. The δ13C and δ18O values of the limestones vary within an individual stromatolite cycle; depleted values characterize the topmost part of the cycles. The isotope pattern is explained by micritic carbonate deposition in different sub environments of the shallow marine domain having different salinity and variable duration of exposure. These variations also probably caused the observed scatter in δ13C and δ18O values of supratidal microbial laminites., © Elsevier

Picobirnaviruses (PBVs) with bisegmented small RNA genome profile (1.75 and 1.55 kbp for segment 1 and 2, respectively) were detected from 1999 to 2003 in faecal specimens of acute watery diarrhoea cases, largely children ( n = 20) and an adult in Kolkata, India. Varying degrees of dehydration necessitated their visit to hospital for further treatment and management of acute watery diarrhoea. PBV was associated with rotavirus ( n = 3) or astrovirus ( n = 3) and with both in one case. No co-infection with norovirus, sapovirus or adenovirus was detected in the picobirnavirus positive cases. No co-infection with parasites ( Cryptosporidium spp., Giardia spp., Entamoeba spp., helminths) or bacteria ( Vibrio spp., Shigella spp., Escherichia coli ) was detected among the picobirnavirus positive cases. There was a single instance of co-infection with Salmonella spp. ( n = 1). PBVs not associated with serious diarrhoea illness and showing large genome profile (2.3–2.6 and 1.5–1.9 kbp for segment 1 and 2, respectively) have earlier been reported in adult individuals and recently among children from a slum community in Kolkata, India. The short genome profile PBVs associated with acute watery diarrhoea may be another emerging diarrhoeagenic virus in Kolkata, India. Molecular characterization using reported primers PicoB25–PicoB43 for Genogroup I and PicoB23–PicoB24 for Genogroup II in RT-PCR showed the presence of Genogroup I PBVs ( n = 6) and Genogroup II PBVs ( n = 5), while some could not be amplified ( n = 3) with these primers. Sequence analysis of Genogroup I amplicons indicated remarkable sequence heterogeneity. After more than a decade, four PBV positives of Genogroup II were detected during this study. Phylogenetic analysis showed varying degree of genetic diversity amongst PBV strains from Kolkata and other countries.

A hospital-based case-control study was carried out to clarify the characteristics of mucoid presentation of acute enterocolitis in children. One hundred sixty-eight cases of acute mucoid enterocolitis (study population) were compared with 200 cases of watery diarrhoea and 118 cases of blood dysentery (control groups) on the basis of clinical characteristics and findings on stool examination. Study and control groups were comparable with respect to age, body weight and nutritional status. There was no significant difference in clinical characteristics (duration of diarrhoea, stool frequency, presence of vomiting, fever and dehydration) between patients suffering from mucoid enterocolitis and blood dysentery. However, watery diarrhoea patients had significantly high frequencies of vomiting (p = 0.00001) and dehydration (p = 0.00001). High numbers of microscopic red blood cells (mean±SD: 40.8 ± 16.8) and white blood cells (40.6 ± 18.0) were present in faecal samples of the patients with mucoid enterocolitis, which is indicative of infection caused by enteroinvasive enteropathogens. Shigella was a commonly identified enteropathogen in patients with mucoid enterocolitis (40.5%) and in patients with dysentery (46.6%), with no statistically significant difference (p= 0.30). Isolation of Salmonella was statistically similar in study and control groups. However, Entamoeba histolytica was detected in significantly high frequency in patients with mucoid enterocolitis as compared to the patients with dysentery (p = 0.0004) and watery diarrhoea (p = 0.00004). Our results indicate that mucoid enterocolitis patients are infected with enteroinvasive enteropathogens, and that stool examination is useful in establishing the aetiological diagnosis. □Acute enterocolitis, diarrhoea, dysentery, Entamoeba histolytica, faecal red and white blood cells, mucoid presentation, Shigella, Salmonella

The protective efficacy of an orally administered heat-killed virulent strain of Shigella flexneri 2a (5 weekly oral doses) was evaluated in 25 rabbits (14 immunized and 11 non-immunized controls) against challenge with the same strain of Shigella using the rabbit model of shigellosis. All 11 non-immunized rabbits developed bloody diarrhoea following challenge and 6 (54%) died. None of the 14 immunized rabbits developed diarrhoea (all had pellet stools) but 3 (21%) died from causes not associated with diarrhoea. Protection from diarrhoea and dysentery following oral immunization with a killed Shigella species was 100% and highly significant. Death following challenge was 2.5-fold higher in the non-immunized group (p= 0.115) but was not significant. These promising results suggest that further studies should be undertaken to develop a killed oral vaccine against shigellosis.

The study is aimed to determine the seasonal distribution and clinical characteristics of astroviruses associated with acute watery diarrhoea among children in Kolkata and characterize them at the molecular level. Method of study Faecal specimens of acute watery diarrhoea cases (n = 857) and non-diarrhoeic samples (n = 211) from the hospitals and a nearby field community were screened with IDEIA Astrovirus detection kit; astrovirus co-infections with rotavirus and/or picobirnavirus were detected by RNA-PAGE and silver staining. Further RT-PCR was carried out using specific primers, viz. Mon340 (+) and Mon348 (−) targeting a highly conserved domain of ORF1a (289 bp) of human astroviruses. Results Astrovirus infection was detected in 50 cases (50/857); astroviruses were detected mostly in children aged 6–12 months (50%); all non-diarrhoeic samples (n = 211) were negative for astrovirus. In 52% of astrovirus positive cases, the virus was detected as the sole agent; mixed infections were also detected with other diarrhoeic pathogens such as rotavirus (32%), picobirnavirus (2%), rotavirus and picobirnavirus (2%), picobirnavirus and Enterotoxigenic E. coli (ETEC) (2%), rotavirus and ETEC (2%), rotavirus and Enteroaggregative E. coli (EAEC) (2%), Enteropathogenic E. coli (EPEC) (2%), Shigella flexneri type 3a (2%) and Ascaris (2%). RT-PCR and sequencing of amplicons of astroviruses from Kolkata, with specific primers targeted to the conserved domain of ORF1a (289 bp) of the astrovirus genome, showed maximum homology to the astrovirus strain (“5–158”) from Seoul (98%). Results and Conclusions Clinical characteristics of the diarrhoeic children in Kolkata indicated that astrovirus infections were detected throughout the year and were associated with varying degree of dehydration and acute watery diarrhoea. In-depth molecular epidemiological surveillance of astroviruses in Kolkata is essential for better understanding of their overall genetic nature.

Background Rotavirus genotypes, G1–G4 and G9 are associated with childhood diarrhoea throughout the world. In our previous study, we detected G1, G2, G4 and three G12 strains from Kolkata, India. Objectives To study the prevalence of G- and P-genotypes of rotaviruses associated with dehydrating diarrhoea in children admitted to two leading hospitals in eastern India. Study design An active surveillance was conducted for elucidation of rotavirus infection in two leading hospitals in Kolkata, West Bengal and Berhampur (GM), Orissa, India, separated by 603 km from January 2003 to April 2005. The rotaviruses were detected by RNA electrophoresis in polyacrylamide gels. G- and P-typing of the positive samples were accomplished by amplifying VP7 and VP4 genes by RT-PCR and genotyped by seminested multiplex PCR methods. Sequencing, sequence analysis and phylogenetic analysis of VP7 genes of G12 strains were carried out to understand the variations between the strains isolated from different parts of the world. Results The genotypic distribution varied remarkably from our earlier study period (1998–2001) with G1 (53.8%) being the most predominant strain followed by G2 (22.5%), G12 (17.1%), G9 (2.1%) and not a single G3 or G4 isolate was detected separately. 35.2% samples exhibited mixed P-types followed by P[4] (31.7%), P[8] (21.8%) and P[6] (9.8%). The phylogenetic analysis of G12 strains revealed that the G12 strains detected from different parts of the world clustered into three different lineages. Though VP7 sequences of G12 strains isolated from Kolkata and Berhampur are conserved, their P-types were different. Conclusion During this study period we reported emergence of G12 strains as an important pathogen among children in eastern India, thus necessitating its inclusion in future polyvalent vaccine to control rotavirus diarrhoea.

Background Human group B rotavirus was first identified as causative agent of a large outbreak of severe gastroenteritis affecting more than 1 million people, predominantly adults in China in 1982–1983. In spite of serological evidences for the presence of group B rotavirus in many countries of the world, the virus has been detected only from China, India and Bangladesh, where most of the cases were from adults. Objectives To ascertain the role of group B rotavirus as an aetiological agent of diarrhoea among children in Kolkata, India. Study design An active surveillance was conducted for rotavirus infection in children in a leading referral paediatric hospital and a few samples were also collected from adults of another hospital in Kolkata, India over a period of 3 years (2002–2004). After primary screening of rotaviruses by RNA electrophoresis in polyacrylamide gel, 200 of 412 samples negative by PAGE were screened by reverse transcription polymerase chain reaction for group B rotaviruses. The group B rotavirus positives samples were also confirmed by dot-blot hybridization. Result During the study period, we detected 37 (18.5%) sporadic cases of human group B rotavirus infection in children below 3 years of age of which 15 (7.5%) showed mixed infection with group A rotaviruses by RT-PCR. In dot-blot hybridization studies the RNA of all rotavirus positive samples hybridized with the nonisotopic psoralen-biotin labeled total RNA probe generated from a human group B rotavirus CAL-1 strain confirming the samples as group B rotaviruses. Conclusion The shift in age preference of group B rotavirus infection from adult to children and mixed infection of group B and group A rotaviruses reveals the importance of group B rotavirus as an etiological agent of childhood diarrhoea. Therefore, future vaccination strategy should include both group A and B rotaviruses to control rotavirus diarrhoea.

A porcine Group A rotavirus strain (RU172) was detected and molecularly characterized during a surveillance study conducted for rotavirus infection in a pig farm located in a suburban area of Kolkata City, India. The G12 genotype specificity of RU172 was revealed by PCR-based genotyping assays following addition of a G12 type-specific primer (designed in our laboratory to pick up G12 isolates from field samples) and was confirmed by sequence analysis of the VP7-encoding gene. The RU172 strain exhibited maximum VP7 identities of 93.6% to 94.5% with human G12 strains at the deduced amino acid level. In spite of its G12 genotype nature, RU172 appeared to be distinct from human G12 rotaviruses and, on phylogenetic analysis, formed a separate lineage with human G12 strains. Among the other gene segments analyzed, RU172 belonged to NSP4 genotype B, had a NSP5 and VP6 of porcine origin, and shared maximum VP4 identities with porcine P[7] rotaviruses (94.3%-95.4% at the deduced amino acid level). Therefore, to the best of our knowledge, this is the first report of detection of an animal rotavirus strain with G12 genotype specificity. Detection of strains like RU172 provides vital insights into the genomic diversity of Group A rotaviruses of man and animals.

Red Fire Ants Are Present In Almost All Countries And In All Places. Because Of Their Resistance To Natural And Chemical Control, Fire Ants Can Overwhelm Their Environment And Destroy Land And Animals. Fire Ants Can Also Cause A Variety Of Health Problems In Humans, Ranging From Simple Stings To Severe Life Threatening Anaphylaxis. Most Of The Deaths Following Red Fire Ant Strings Are Reported From South-Eastern United States And Australia. We Report A Three-Year-Old Child, Known Allergic To Ant-Venom, Who Died From Severe Anaphylactic Reactions Following Multiple Red Fire Ant Strings (Solenopsis Geminata). This Type Of Presentation Following Red Fire Ant Strings Is Probably First Time Reported From India. Beside Clinical Diagnosis, Significance Of Laboratory Investigations Including Postmortem Examinations In Fatal Anaphylaxis Is Also Discussed Here.

HIV-1 subtype C is the major subtype in India as evidenced from the analysis of specific regions within envelope and gag gene. The matrix protein (p17) of HIV-1 which is involved in several functions like the viral RNA transport, nuclear localization, assembly of pre-integration complex into host nucleus has been used to study the strain diversity among female sexworkers in Calcutta. The gene encoding for the HIV-1 matrix protein, p17 was amplified by nested polymerase chain reaction (PCR) from blood samples of HIV-1 seropositive female sex workers (FSW) in Calcutta, India. Genes of twenty-two samples were sequenced and the phylogenetic analysis with different global strains showed that the majority (seventeen) was clustered with Indian type C. A few samples were found to be close to other C subtypes isolated from South Africa, China and Myanmar. The comparison of Calcutta samples with the samples from other regions of India along with other non-asian subtype C sequences clearly revealed a different cluster of Indian sequences. The two samples, cal 242 and cal 709 was found to be the most divergent type and showed close relatedness with African C subtypes.

An investigation was conducted to determine the distribution, virulence gene profile and phenotypes of Shiga toxin-producing Escherichia coli (STEC) strains within a dairy farm in Kolkata, India by characterizing the STEC strains isolated from healthy dairy cow and calf stool samples, raw milk and farm floor swabs from July 2001 to March 2002. Primary screening by multiplex-PCR detected stx1 and stx2, the common virulence genes of STEC, in 18.9% of cow faeces, 32.4% of calf stool samples, 21.6% of farm floor swabs and 4.5% of raw milk samples and viable STEC were recovered from 4.5, 9.9, 8.1 and 1.8% of the corresponding PCR-positive samples. Strains harbouring stx1 (63.3%) and hlyA (53.3%) were frequently detected compared to eae (13.3%). Most of the strains harboured similar sets of reported virulence genes common among isolates from diarrhoea patients. Most of the strains also exhibited multidrug resistance, sorbitol fermentation and produced enterohaemolysin. The randomly amplified polymorphic DNA-PCR (RAPD-PCR) profile of the STEC strains isolated from the farm milieu revealed diverse banding patterns and clonal analysis demonstrated that the strains from different sources were not identical but showed some genetic relatedness. The study demonstrates the potential of dairy farm for housing virulent STEC.

Background :In recent years, hepatitis C virus (HCV) infection is gaining importance in Asian countries. Recent studies conducted in different parts of the world revealed that there is a genotypic correlation of disease severity and treatment outcome. Objectives : A detailed study was carried out to delineate the genotypic distribution of HCV among acute and chronic liver disease patients in Kolkata, a city in eastern India. Study design : Acute and chronic liver disease was diagnosed among patients attending hepatitis clinics in the city. Anti-HCV ELISA was performed on the blood samples of the cases and positive samples were tested for presence of HCV–RNA and genotyping of the samples were carried out by reverse transcription and polymerase chain reaction (RT-PCR) and sequencing. Results : Seroprevalence of HCV infection among acute (11.0%) and chronic (25.3%) hepatitis patients were high and among them 97 (75.8%) and 323 (86.1%) were HCV–RNA positive for acute and chronic hepatitis patients, respectively. Genotyping by PCR showed that the predominant genotype was 3b (42.3%) followed by 3a (28.9%) among acute hepatitis group whereas among chronic hepatitis group, the most prevalent genotypes were 3a (34.7%) and 3b (47.7%). Sequence analysis of the untypeable isolates revealed the presence of a rare subtype 6b. Conclusions : The study revealed very high prevalence of HCV among acute and chronic hepatitis patients with predominance of genotype 3. Subtype 6b was commonly found in Thailand but not in India. The detection of this rare strain of Thai origin reveals the spread of HCV infection from Thailand to other parts of Asia. This observation necessitates further intensive surveillance of HCV infection in India to unravel the distribution of genotypes in the country and to correlate disease severity and treatment outcome to the genotype prevalence. © 2004 Elsevier B.V. All rights reserved.

A comprehensive study was performed to examine incidence, species distribution, drugs sensitivity, virulence genes and molecular fingerprints of Aeromonas species isolated from patients with acute diarrhoea over a period of 2 years in Kolkata, India. Following the Aerokey II scheme, more than 95 % of strains were identified to species level. Seven different species were encountered in this study, with Aeromonas caviae being dominant, followed by Aeromonas hydrophila and Aeromonas veronii biovar sobria. Thirty different serotypes were encountered, with O16, O83 and O85 being dominant, but no serotype was associated specifically with a single species. The majority of Aeromonas strains exhibited multidrug resistance. The alt and act genes, which encode heat-labile cytotonic and cytotoxic enterotoxins, were respectively found in 71.9 and 20.1 % of strains examined. Only 2.4 % of strains carried the heat-stable cytotonic enterotoxin (ast) gene. The hlyA gene was found in 28 % of Aeromonas strains. With few exceptions, genomic diversity of Aeromonas strains belonging to the same serotype was observed by random amplification of polymorphic DNA PCR and ribotyping. Different species of Aeromonas and different clones of Aeromonas species seem to be associated with hospitalized cases of diarrhoea in Kolkata, India.

Since the first report of HIV/AIDS in India in 1986, continuous serosurveillance has been undertaken in all Indian states. Recently, five cases of HIV-2 infection have been detected in Calcutta, situated in the eastern part of India. The full-length envelope gene (2.5 kb) of one of the strains was amplified, cloned, and sequenced. Phylogenetic analysis of the Calcutta HIV-2 envelope revealed a close relatedness to the HIV-2 Rod sequence isolated in offshore Senegal. This strain, however, showed a genetic diversity of 13.5% to other Indian HIV-2 isolates.

A single locality of the Late Cretaceous (Maastrichtian) Lameta Formation at Pisdura in Central India has yielded a large number of coprolites attributed to titanosaurian dinosaurs. Internally the coprolites are dark grey and contain abundant plant tissues and other organic materials. The plant tissues are mostly of gymnospermous origin. In addition, remains of bacterial colonies, fungal spores and algae are seen in the macerated fraction under scanning electron microscope. The dark grey appearance is probably attributable to fine-grained organic matter within voids in tracheids or xylem. The average 13C/12C ratio of the organic matter in the coprolites is -24‰ (relative to PDB) suggesting that plants of C3type were the main diet of their producers. A comparison of δ15N value (about 4‰ w.r.t. air) of the coprolites with that of faecal matter of modern herbivores and carnivores suggests that gut fermentation may not have been an active mechanism in the digestion process of titanosaurs.

Virulence-associated genes and neutral DNA markers of Helicobacter pylori strains from the Santhal and Oroan ethnic minorities of West Bengal, India, were studied. These people have traditionally been quite separate from other Indians and differ culturally, genetically, and linguistically from mainstream Bengalis, whose H. pylori strains have been characterized previously. H. pylori was found in each of 49 study participants, although none had peptic ulcer disease, and was cultured from 31 of them. All strains carried the cag pathogenicity island and potentially toxigenic s1 alleles of vacuolating cytotoxin gene ( vacA ) and were resistant to at least 8 μg of metronidazole per ml. DNA sequence motifs in vacA mid-region m1 alleles, cagA , and an informative insertion or deletion motif next to cagA from these strains were similar to those of strains from ethnic Bengalis. Three mobile elements, IS 605 , IS 607 , and IS Hp608 , were present in 29, 19, and 10%, respectively, of Santhal and Oroan strains, which is similar to their prevalence in Bengali H. pylori. Thus, there is no evidence that the gene pools of H. pylori of these ethnic minorities differ from those of Bengalis from the same region. This relatedness of strains from persons of different ethnicities bears on our understanding of H. pylori transmission between communities and genome evolution.

Long electropherotype with Subgroup I specificity is a common feature of animal rotaviruses. In an epidemic of infantile gastroenteritis in Manipur, India, long but SG I strains predominated in the outbreak in the year 1987-88. One such strain isolated from that region, following the outbreak had G9P [19] specificity. As this is a rare combination, the gene sequences encoding VP4, VP6, VP7, NSP1, NSP2, NSP3, NSP4 and NSP5 of this strain were analyzed. All these genes except VP7 were closely related to porcine rotaviruses (95-99% identity at amino acid level) and clustered with the porcine strains in phylogenetic analysis. In addition, it had subgroup I nature and belonged to NSP4 genotype B which is characteristic of animal rotaviruses. This is the first report of a rotavirus with VP6 and NSP4, two crucial proteins thought to be involved in host range restriction and pathogenicity, were of porcine origin and caused diarrhoea in a human host. Among the genes of this strain sequenced so far, only VP7 had highest identity to human strains at amino acid level. This study suggests reassortment may be occurring between human and other animal strains and some of the reassortant viruses may be virulent to humans.

Red rice is the reservoir of large amount of phytochemicals such as carotenoids, phenolics, alkaloids, nitrogen and organosulfur containing compounds, possesses antioxidant properties, richer source of protein, zinc and have nutritive and medicinal value. Present study examines the utility of red rice accessions for their resistance against Brown planthopper (BPH), a damaging insect pest of rice. A total of 215 red rice accessions along with susceptible check TN1, resistance checks PTB-33 and Salkathi were evaluated under greenhouse condition of the National Rice Research Institute (NRRI), Cuttack. Accessions were screened using standard seed box technique for mass screening followed by replicated screening for the confirmation of resistant reaction. Only four accessions, namely, matameher, manipuri black sonahanan and hormonona were found to be highly resistant (score-1) while eleven showed resistant reaction (Score-3) and 13 were moderately resitant (Score-5) to BPH. Mechanism of resistance was studied in the resistant accessions through the method of antixenosis or nymphal preference to plants. Matameher and manipuri black showed least nymphal preference as compared to the susceptible check TN1. Resistant genotypes identified and confirmed in the present study can be grown as resistant varieties in BPH endemic areas and also can be utilised in resistance breeding programme to develop BPH-resistant varieties with other desired traits.

Enriched13C/12C ratios with δ13C ∼3%0 (w.r.t PDB) of two Late Riphean (∼ 700-610 Ma) intracratonic carbonate successions viz., Bhander Limestone of Vindhyan Basin and Raipur Limestone of Chattisgarh Basin suggest higher organic productivity during this period. This view is supported by sedimentological evidence of higher biohermal growth and consequent increase in depositional relief in the low gradient ramp settings inferred for these basins. Oxygen isotope analysis of these carbonates show distinct segregation between enriched deeper water carbonate mudstone and depleted shallow water stromatolite facies that received fresh water influx. This shows that facies-specific analyses can be useful in understanding the depositional setting of these sediments.

A combined reverse transcriptase-polymerase chain reaction (RT/PCR) was used to produce cDNA of the VP7 gene of rotavirus present in the stool samples. A total of 150 rotavirus positive stool samples were used in this study. Multiplex PCR, using the type specific primers, revealed the presence of G1 (49/150, 32.7%), G2 (27/150, 18%) and G4 (30/150, 20%) genotypes among the samples collected during 1999-2000 from children suffering from acute watery diarrhea. Eighteen samples (12%) were of mixed genotype and the remaining 16 samples (10.6%) could not be typed. Comparative analysis of the full length genes of the representative strains with corresponding genotypes incorporated in the human-rhesus rotavirus tetravalent vaccine (RRV-TV) formulation demonstrates variations of the circulating G1, G2 and G4 strains with the corresponding G genotypes present in the vaccine strain.

We compared putative molecular markers of virulence ( vacA , cagA , and iceA ) of Helicobacter pylori strains isolated from 52 adult duodenal ulcer patients from West Bengal, India, with those of H . pylori strains isolated from 48 adult healthy volunteers from the same region. On the basis of genotyping by PCR, we conclude that the H. pylori strains isolated from the two study groups were indistinguishable and that there are geographic variations in the association of certain putative H. pylori virulence genes with clinical status.

Artemisinin (ART) is a well-known anti-malarial drug, and recently it is shown prospective to selectively kill cancer cells. But low potency makes it inappropriate for use as an anticancer drug. In this study, we modulated the ART-induced autophagy to increase Potency of ART as an anticancer agent. ART reduced the cell viability and colony forming ability of non-small lung carcinoma (A549) cells and it was non-toxic against normal lung (WI38) cells. ART induced autophagy at the early stage of treatment. Pre-treatment with chloroquine (CQ) and followed by ART treatment had synergistic combination index (CI) for cell death. Inhibition of autophagy by CQ pre-treatment led to accumulation of acidic vacuoles (AVOs) which acquainted with unprocessed damage mitochondria that subsequently promoted ROS generation, and resulted releases of Cyt C in cytosol that caused caspase-3 dependent apoptosis cell death in ART-treated A549 cells. Scavenging of ROS by antioxidant N-acetyl-cysteine (NAC) inhibited caspase-3 activity and rescued the cells from apoptosis. Similar effects were observed in other cancer cells SCC25 and MDA-MB-231. The appropriate manipulation of autophagy by using CQ provides a powerful strategy to increase the Potency of selective anticancer property of ART.

In Ahmedabad, a major city in the state of Gujarat, India, an outbreak of acute secretory diarrhea caused by Vibrio cholerae O1 Ogawa El Tor, V. cholerae O139, and multiple serotypes of enterotoxigenic Escherichia coli (ETEC) occurred in January 2000. All of the representative V. cholerae O1 and O139 isolates examined harbored the ctxA gene (encoding the A subunit of cholera toxin) and the El Tor variant of the tcpA gene (encoding toxin-coregulated pilus). ETEC isolates of different serotypes were positive for the elt gene, encoding heat-labile enterotoxin. To further understand the molecular characteristics of the pathogens, representative isolates were examined by ribotyping and pulsed-field gel electrophoresis (PFGE). Ribotyping showed that the isolates of V. cholerae O1 Ogawa exhibited a pattern identical to that of the prevailing clone of O1 in areas where cholera is endemic in India, and all of the O139 isolates were identical to the BII clone of V. cholerae O139. PFGE of the representative O1 Ogawa isolates exhibited an identical pattern, comparable to the H pattern of the new clone of O1 reported in Calcutta, India. PFGE analysis of the V. cholerae O139 isolates showed identical patterns, but these differed from the PFGE patterns of O139 isolates reported during 1992 to 1997 in Calcutta. ETEC isolates showed genetic heterogeneity among isolates belonging to the same serotype, although the identical PFGE pattern was also observed among ETEC isolates of different serotypes. Antibiograms of the isolates were unusual, because all of the O139 isolates were resistant to nalidixic acid. Likewise, all of the E. coli isolates showed resistance to ciprofloxacin, norfloxacin, and nalidixic acid. This is a unique outbreak, and we believe that it is the first in which V. cholerae and ETEC were concomitantly involved.

The gene coding for outer capsid protein, VP7 of rotaviruses detected among the children suffering from watery diarrhea in the eastern part of India was studied. The full length gene, coding for VP7 was synthesized from a local strain, WD33, by combined reverse transcriptase–polymerase chain reaction. A total of 42 fecal RNA out of 93 rotavirus-positive samples hybridized with this DNA, indicating the prevalence of this strain in the community. Comparison of the nucleotide and deduced amino acid sequence with the VP7 gene of other serotypes revealed that the local strain,WD33, resembled closely with G1 serotype, the homology being 94 and 97%, respectively. Multiplex PCR using the specific oligonucleotide primers also amplified the G1 specific DNA fragment. The overall change of 16 amino acids was noticed when compared with G1 specific prototype Wa strain of which nine amino acids are within the neutralization domain. However, the phylogenetic tree constructed by comparing the G1 strains from different countries demonstrated that this strain WD33 clustered as a distinct sub-lineage of lineage IV and not with Wa strain, that clustered with lineage III.

In order to assess the extent of genomic diversity among Vibrio cholerae O139 strains, restriction fragment length polymorphisms in two genetic loci, rrn and ctx, were studied. Analysis of 144 strains isolated from different regions of Bangladesh and India between 1992 and 1998 revealed the presence of at least six distinct ribotypes (B-I through B-VI) of which three were new ribotypes, and one of these was represented by a nontoxigenic O139 strain. Strains of ribotypes B-I through B-V shared 11 different CTX genotypes (A through K). Antimicrobial resistance patterns of the strains varied independently of their ribotypes and CTX genotypes. Results of this study suggest that V. cholerae O139 is undergoing rapid genetic changes leading to the origination of new variants, and temporal changes in antimicrobial resistance patterns may be contributing to the selection of different variants.

δ18 O and δ13C of G.sacculifer have been measured in five cores from the northern Indian Ocean. In addition, high resolution analysis (1 to 2 cm) was performed on one core (SK-20-185) for both δ18O and gd13C in five species of planktonic foraminifera. CaCO3 variation was measured in two cores. The results, presented here, show that • the summer monsoon was weaker during 18 ka and was stronger during 9 ka, relative to modern conditions; • δ13C variations are consistent with independent evidence that shows that during the last glacial maximum (LGM; 18 ka) the upwelling was reduced while during 9 ka it was vigorous; • calculation of CaCO3 flux shows that the LGM was characterized by low biogenic productivity in the Arabian Sea while during the Holocene productivity increased by ∼65%, as a direct consequence of the changes in upwelling. Similar changes (of lesser magnitude) are also seen in the equatorial Indian Ocean. The amount of terrigenous input into the Arabian Sea doubled during LGM possibly due to the higher erosion rate along the west coast. • δ18O values indicate that the Arabian Sea was saltier by 1 to 2%o during LGM. The northern part was dominated by evaporation while in the equatorial part there was an increased precipitation.

The scenario of cholera that existed previously changed in 1992 and 1993 with the emergence of toxigenic Vibrio cholerae O139 in India. The genesis of the new serogroup formed the impetus to search for O139 phages in and around the country. A total of five newly isolated phages lytic to V. cholerae O139 strains were used for the development of this phage typing scheme. These phages differed from each other and also differed from the existing O1 phages in their lytic patterns, morphologies, restriction endonuclease digestion profiles, and immunological criteria. With this scheme, 500 V. cholerae O139 strains were evaluated for their phage types, and almost all strains were found to be typeable. The strains clustered into 10 different phage types, of which type 1 (38.2%) was the dominant type, followed by type 2 (22.4%) and type 3 (18%). Additionally, a comparative study of phage types in 1993 and 1994 versus those from 1996 to 1998 for O139 strains showed a higher percentage of phage type 1 (40.5%), followed by type 3 (18.8%) during the period between 1993 and 1994, whereas phage type 2 (32.1%) was the next major type during the period from 1996 to 1998. This scheme comprising five newly isolated phages would be another useful tool in the study of the epidemiology of cholera caused by V. cholerae O139.

Since 1996 infections caused by Vibrio parahaemolyticus have increased globally. Outbreak and/or sporadic cases of diarrhea caused by V. parahaemolyticus have been reported from India Indonesia Japan Taiwan the USA Laos Korea Chile Bangladesh Russia Thailand Spain France and Vietnam. This increase in incidence appears to be related to the emergence of a new clone belonging to the O3:K6 serovar which has pandemic potential. Due to its spread in many countries with identical phenotypic and genotypic features the recently emerged V. parahaemolyticus has now been termed a pandemic strain which can be identified by group-specific GSPCR based on the sequence variation in the toxRS gene. In addition the pandemic strains have a novel open reading frame orf8 which corresponds to a filamentous phage f237. On September 14 2003 an outbreak of diarrhea occurred near Dumdum in Kolkata India. About 200 people had diarrhea after consumption of rice with meat served at the blood donation camp. Twenty-one patients were admitted to the Infectious Diseases Hospital (IDH) Kolkata from this outbreak-affected area. Stool specimens were collected from all the patients and screened for common enteric pathogens within two hours of collection using standard methods. In addition 3--5 Escherichia coli colonies grown in MacConkey agar from each stool specimen were screened for diarrheagenic E. coli (DEC) by PCR.4 In this assay all the tested E. coli isolates were negative for common DEC such as enterotoxigenic E. coli enteropathogenic E. coli and enteroaggregative E. coli. (excerpt)

We report the prevalence of the O139 serogroup in Calcutta, India, after its reemergence in August 1996 and the spread of the reemerged clone to other parts of the country by using previously established molecular markers. Phenotypically, the reemerged Vibrio cholerae O139 displayed a difference compared to those that appeared in late 1992 and 1993 in that the current O139 strains are sensitive to co-trimoxazole. Ribotyping with the enzyme Bgl I produced two rRNA restriction patterns in the O139 strains isolated after August 1996, and these patterns were identical to those exhibited by strains of O139 isolated in 1992. Three clones of V. cholerae O139 are currently prevailing in the country, with strains exhibiting three bands after Hin dIII digestion and hybridization with a ctxA probe being dominant. The reemergence of V. cholerae O139 in Calcutta after a 32-month quiescent period reestablishes the O139 serogroup as an entity which is likely to play a crucial role in the temporal antigenic variations among the serogroups of V. cholerae causing cholera.

There was an inexplicable upsurge in the incidence of non-O1, non-O139 Vibrio cholerae among hospitalized patients admitted to the Infectious Diseases Hospital, Calcutta, India, between February and March 1996. Of the 18 strains of V. cholerae isolated during this period, 15 belonged to the non-O1, non-O139 serogroups (4 belonged to O144, 3 belonged to O11, 1 each belonged to O6, O8, O12, O19, O39, and O58, and 2 strains could not be typed), 2 belonged to the O139 serogroup, and 1 belonged to the O1 serogroup. Cell-free culture supernatants of 13 representative non-O1, non-O139 V. cholerae strains evoked a distinct cytotoxic effect on CHO and HeLa cells, and the strains examined produced the nonmembrane-damaging cytotoxin. By several PCR assays, it was determined that none of the non-O1, non-O139 strains were positive for the ctxA , zot , ace , and tcpA genes and for the genes representing the heat-labile toxin, heat-stable toxin, and verotoxin of Escherichia coli and the various variants of these genes. Studies on the clonality of non-O1, non-O139 V. cholerae strains by restriction fragment length polymorphism (RFLP) analysis of rRNA genes and of other genes ( hlyA , hlyU , hlx , toxR , and attRS1 ) and by pulsed-field gel electrophoresis (PFGE) collectively indicate that the upsurge which occurred in February and March 1996 was caused by strains belonging to different clones. Overall, there was an excellent correlation between the results of ribotyping, RFLP analysis of various genes, and PFGE, with strains belonging to a particular serogroup showing nearly identical restriction patterns and PFGE profiles. It is clear from this study that some serogroups of V. cholerae can cause diarrhea by a mechanism quite different from that of toxigenic V. cholerae O1 and O139, and we have proposed the nomenclature of enteropathogenic V. cholerae to include these serogroups.

After a lapse of 33 months, Vibrio cholerae O139, the new serogroup associated with cholera, has re-emerged in Calcutta, India and has become the dominant serogroup causing cholera from September 1996. In neighbouring Bangladesh, V. cholerae O1 biotype El Tor continues to be the dominant cause of cholera with the O139 serogroup accounting for only a small proportion of cases. Comparison of the phenotypic traits of representative O139 strains from Calcutta and Dhaka isolated between December 1996 and April 1997 showed similar phenotypic traits with the exception that Dhaka O139 strains were susceptible to streptomycin whilst Calcutta O139 strains were resistant. The Dhaka and Calcutta O139 strains displayed identical ribotypes but showed remarkable differences in the structure and organization of the CTX genetic element. In the Dhaka O139 strains, two copies of the CTX element were arranged in tandem and this resembled the pattern displayed by the 1992 epidemic strains of O139. The Calcutta O139 strains, in contrast, carried three copies of the CTX genetic element arranged in tandem with the loss of a conserved BglII restriction site in the RS1 element and the appearance of a new HindIII site in the same region. While there may be other factors, it appears that the reorganization of the CTX genetic element in the Calcutta O139 strains may have contributed to the resurgence of this serogroup in Calcutta.

In this study, pulsed-field gel electrophoresis (PFGE) was applied to determine if the Vibrio cholerae O1 strains which reappeared after being temporarily displaced in Calcutta by the O139 serogroup were different from those isolated before the advent of the O139 serogroup. NotI digestion generated a total of 11 different patterns among the 24 strains of V. cholerae randomly selected to represent different time frames. Among the V. cholerae O1 strains isolated after July 1993, 4 PFGE banding patterns designated as H through K were observed with pattern H dominating. Pattern H was distinctly different from all other patterns encountered in this study including patterns A, B and C of V. cholerae O1 El Tor, which dominated before November 1992, and pattern F, which was the dominant V. cholerae O139 pattern. Further, pattern H was also different from the NotI banding patterns of the representative strains of the 4 toxigenic clonal groups of V. cholerae O1 El Tor currently prevailing in different parts of the world. NotI fragments of the new clone of V. cholerae O1 did not hybridize with an O139 specific DNA probe, indicating that there was no O139 genetic material in the new clone of V. cholerae O1. Hybridization data with an O1-specific DNA probe again differentiated between the clones of V. cholerae O1 existing before the genesis of the O139 serogroup and the O1 strains currently prevalent.

Thiadiazoles are one of the most widely utilized agents in medicinal chemistry, having a wide range of pharmacologic activity. Microtubules (MTs) have always remained a sought-after target in rapidly proliferating cancer cells. We screened for the growth inhibitory effect of synthetic 5-(3-indolyl)-2-substituted-1,3,4-thiadiazoles on cancer cells and identified NMK-TD-100, as the most potent agent. Cell viability experiments using human cervical carcinoma cell line (HeLa cells) indicated that the IC50 value was 1.42±0.11 µM for NMK-TD-100 for 48 h treatment. In further study, we examined the mode of interaction of NMK-TD-100 with tubulin and unraveled the cellular mechanism responsible for its anti-tumor activity. NMK-TD-100 induced arrest in mitotic phase of cell cycle, caused decline in mitochondrial membrane potential and induced apoptosis in HeLa cells. Immunofluorescence studies using an anti-α-tubulin antibody showed a significant depolymerization of the interphase microtubule network and spindle microtubule in HeLa cells in a concentration-dependent manner. However, the cytotoxicity of NMK-TD-100 towards human peripheral blood mononuclear cells (PBMC) was lower compared to that in cancer cells. Polymerization of tissue purified tubulin into microtubules was inhibited by NMK-TD-100 with an IC50 value of 17.5±0.35 µM. The binding of NMK-TD-100 with tubulin was studied using NMK-TD-100 fluorescence enhancement and intrinsic tryptophan fluorescence of tubulin. The stoichiometry of NMK-TD-100 binding to tubulin is 1:1 (molar ratio) with a dissociation constant of ~1 µM. Fluorescence spectroscopic and molecular modeling data showed that NMK-TD-100 binds to tubulin at a site which is very near to the colchicine binding site. The binding of NMK-TD-100 to tubulin was estimated to be ~10 times faster than that of colchicine. The results indicated that NMK-TD-100 exerted anti-proliferative activity by disrupting microtubule functions through tubulin binding and provided insights into its potential of being a chemotherapeutic agent.

SUMMARYThe distribution and virulence ofVibrio choleraeserogroups other than O1 and O139 in India before, during and after the advent of O139 serogroup was investigated. A total of 68 strains belonging to 31 different ‘O’ serogroups were identified during the study period. With the exception of O53, there was no spatial or temporal clustering of any particular non-O1 non-O139 serogroup at any given place. Two of the 68 strains examined produced cholera toxin (CT) which could only be partially absorbed with anti-CT immunoglobulin G. Tissue culture assay revealed that some of the non-O1 non-O139 strains produced factors which evoked either a cell rounding or cell elongation response depending upon the medium used. This study indicates that serogroups other than O1 and O139 should also be continuously monitored.

Three rare human G12 strains were detected from diarrheic clinical samples of children (

N-Acetyl-D-glucosamine specific cell-associated hemagglutinin (HA)/lectin, previously purified from a strain of Vibrio cholerae O1, had been established as an adhesin molecule of V. cholerae O1 cells. This communication records the isolation and purification of the glycoprotein receptor of the N-acetyl-D-glucosamine specific HA of the V. cholerae O1 strain from chicken erythrocyte membranes. The most salient feature of this study is that the pretreatment of partially purified glycoprotein with purified HA could completely inhibit the hemagglutinating activity of the V. cholerae O1 strain with chicken erythrocytes.

Summary A collection of 28 strains of Vibrio cholerae non-O1 isolated during a 3-year period (1989–1991) from hospitalised patients with acute diarrhoea in Calcutta, India, were examined with regard to virulence-associated factors. Of the 28 isolates (each representing a case), 18 were isolated as the sole infecting agent; the remaining 10 were recovered as co-cultures from cases infected with V. cholerae O1. Of the strains isolated in this study, 82% could be serotyped, with serovars O5 (32·1%), O11 and O34 (14·3% each) predominant. Serovars O7, O14, O34, O39 and O97 were associated exclusively with sole infections. Two strains of V. cholerae non-O1 produced anti-cholera toxin IgG-absorbable cholera toxin (CT). Both CT-producing V. cholerae non-O1 strains hybridised with the DNA probe specific for the zonula occludens toxin (ZOT) but none of the remaining 26 strains hybridised with the ZOT probe. The majority of the strains were cytotoxic for CHO, HeLa and Vero cells, with end-point titres of 4–512. Fewer strains produced a cytotonic effect, with end-point titres of 2–16. Of the 28 strains of V. cholerae non-O1 examined, 75%, 75%, 25% and 14·3% produced haemolysin that was active against erythrocytes of rabbit, sheep (Eltor haemolysin), chicken and man, respectively. Strains that produced a haemolysin active against both rabbit and sheep erythrocytes were dominant (35·7%). Ten (35·7%) of the 28 strains examined showed cell-associated haemagglutinating activity on human blood. Of the 10 strains, nine were isolated as sole pathogen and only one strain was associated with mixed infection. Three distinct patterns of inhibition by sugars were detected; inhibition of haemagglutination by mannose 1% but not by fucose and galactose 1% was the dominant haemagglutination inhibition pattern. Six different virulence phenotypes were encountered among strains of V. cholerae non-O1 in this study. The prominent phenotype, which was associated commonly with isolates from patients solely infected by V. cholerae non-O1, was exhibited by strains that produced the Eltor haemolysin, a cytotoxin and a cell-associated haemagglutinin. The production of cell-associated haemagglutinin appeared to be the only distinctive phenotype that could distinguish between isolates from patients solely infected with V. cholerae non-O1 and those associated with mixed infections. From this study, it is apparent that the virulence of V. cholerae non-O1 is multifactorial and mediated by several traits functioning in an integrated fashion. The clinical significance of V. cholerae non-O1 must be assessed in its totality; the presence of a single factor should not be construed as the cause of enteropathogenicity.

A survey was conducted to study the genetic differentiation among 16 tribal groups of Orissa, Madhya Pradesh, and Maharashtra belonging to different ethnic and linguistic affiliations. Sixteen hundred and fifteen blood samples from both sexes were tested for 5 red cell enzyme systems: ACP, ESD, PGD, GLO, LDH, and Hb pattern. Three hundred and nineteen male individuals were tested for G-6-PD enzyme deficiency. The distribution of the enzyme markers and Hb show a range of variation which are more or less within the Indian range. Cases of homozygous HbSS were detected in all the tribes except 3 tribes in Orissa. Two cases of LDH Cal-1 homozygote were found in two Dravidian language speaking Orissa tribes. The chi 2-values for testing the homogeneity of gene frequencies indicate a non-significant heterogeneity for all alleles in the individual system. Within population diversity seems to be larger than between population diversity. The degree of over all genetic differentiation as measured by GST value is 0.0154 +/- 0.0071.