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Highly similar genetic and phenotypic traits of at least eight bacterial species forming the ‘Bacillus cereus group’ create their precise identification and differentiation quite difficult. The present study explores the applicability of a previously suggested multiplex-PCR method for the accurate identification of the candidate Bacillus species. Out of the 257 Bacillus isolates collected from soil, 44 were identified as B. thuringiensis and 39 as B. cereus by chromogenic cultural method using Bacillus agar, although few of them shared similar colony characteristics. Identification by the multiplex PCR in a thermo cycler using 5 different sets of primer-pairs, however produced distinct amplification corresponding to the bacterial species. Four of those pairs, named BMSH, BCJH, BTJH and BASH were designed based on gyrB gene that produced amplicons of four different sizes: 604, 475, 299 and 253 bp and were specific for B. mycoides, B. cereus, B. thuringiensis, and B. anthracis respectively. The remaining one of the sets was used as an internal control which was a universal primerpair, BCGSH, designed targeting a housekeeping gene, groEL that could produce an amplicon of 400 bp in polymerase chain reactions for all members of the B. cereus group, When probing the chromosomes extracted from 257 Bacillus isolates by multiplex PCR; 48, 39 and 5 were identified as B. thuringiensis, B. cereus, and B. anthracis respectively, however the rest of the isolates did not any amplification. Interestingly, the phylogenetic tree, constructed based on partial sequences of 16S rRNA genes of selected isolates including the reference strain of B. thuringiensis (HD-73, sotto) could not differentiate the species, instead posited those in a single cluster. The multiplex PCR, therefore, proved to be a sensitive and reliable method for the identification of the bacterial candidates of Bacillus cereus group than that of cultural and rRNA gene sequence analyses. Bangladesh J Microbiol, Volume 39, Number 1, June 2022, pp 21-29

This global survey of vAh brought together scientists that study fish disease to evaluate the evolution, geographical distribution, phylogeny, and hosts of vAh and other Aeromonas sp. isolates. In addition to vAh isolates from China and the United States, four new vAh isolates were isolated from the lower Mekong River basin in Cambodia and Vietnam, indicating the significant threat of vAh to modern aquaculture and the need for improved biosecurity to prevent vAh spread.

Despite the widely used author contribution criteria, unethical authorship practices such as guest, ghost, and honorary authorship remains largely unsolved. We have identified six major reasons by analyzing 78 published papers addressing unethical authorship practice. Those are lack of: (i) awareness about and (ii) compliance with authorship criteria, (iii) universal definition and scope for determining authorship, (iv) common mechanisms for positioning an author in the list, (v) quantitative measures of intellectual contribution; and (vi) pressure to publish. As a possible measure to control unethical practice, we have evaluated the possibility to adopt an author categorization scheme ��� proposed according to the common understanding of how first-, co-, principal-, or corresponding- author is perceived. Based on an online opinion survey, the proposed scheme was supported by ~80% of the respondents (n=370). The impact of the proposed categorization was then evaluated using a novel mathematical tool to measure ���Author Performance Index (API)��� that can be higher for those who might have authored more papers as primary and/or principal authors than those as coauthors. Hence, if adopted, the proposed author categorization scheme together with the API would provide a better way to evaluate the credit of an individual as a primary and principal author.

Genome sequence study of an industrially-important strain, Bacillus subtilis M9, a mutant version of wild strain Bacillus subtilis MZK05 was conducted to uncover genetic factors responsible for enhanced serine proteases expression in addition to its other industrial enzymes, metabolites and bacteriocins producing efficacy. The wild type and the mutant genome contained a size of 4,145,727 and 4,045,950 bp, with 4,352 and 4,383 genes; and 477 and 478 subsystems respectively. Genomic comparison with 31 B. subtilis sourced from different countries showed both wild and mutant shared same type of genome structure with 20 others. Moreover, 6,000 kb pangenome showed that they share 3082, 1449, and 25757 core, unique and accessory genes respectively. A sum of 32,559 mutations were found with three major genomic structural changes in the upstream and downstream of an extracellular alkaline serine protease, AprX and a periplasmic serine protease, HtrC in M9 genome when compared to the wild type. Furthermore, 11 different serine protease genes and 4 different signal peptidases were found with several mutational changes in M9. In addition, mutations found in core genome of BsM9 in phage-like element, major capsid protein, and phage portal protein are the likely reasons of high-level serine protease activity.

Considering the fact that publications serve as an important criterion to evaluate the scientific accomplishments of an individual within respective fields in academia, there has been an increasing trend to publish scientific articles whereby multiple authors are defined as primary, co-, or corresponding authors according to the roles performed. This article analyzes the authorship pattern in 4,561 papers (including 60 single-authored papers) from 1990 till 2020 of 94 academics who hold a position as professors and are affiliated with the Faculty of Medicine at three different research universities in Malaysia. Only 708 papers (15.5% of 4,561 papers) were authored by less than three authors. In 3,080 papers (67.5% of 4,561 papers), those academics appeared as coauthors. Using different years as cutoff periods, it was observed that the appearance as coauthor in the papers had steeply risen around the years: 2006, 2007, 2008 and onwards. The increased number of authors in the multi-author papers and the appearance of the selected academics as coauthors reflect the extent of boosting of collaborative research in that period which corresponds to the adoption of the "publish or perish policy" by the Ministry of Higher Education in Malaysia.

A 58-year-old man was tested positive for COVID-19 with mild clinical symptoms. Although symptoms resolved within 2 days, the patient was tested positive again on day 29 post-illness after a negative test. It took more than 40 days to become a negative carrier of SARS-CoV-2. Such asymptomatic cases raise questions on the recommended isolation period. If not contained, these asymptomatic carriers could create challenges for disease control by allowing infection back to the community. A lengthened isolation of patients with COVID-19 for 6 weeks postillness could be a safeguard for the community. Bangladesh Journal of Medical Science Vol.20(1) 2021 p.187-189

Serological analysis is an integral part of laboratory practice nowadays. The present study was aimed to develop and validate a modified Enzyme linked Immunosorbent Assay (ELISA) for determination of IgG antibody against Hepatitis E Virus (HEV) using dried blood spots (DBS) and corresponding plasma samples. A total of 65 samples (45 HEV patients, 20 healthy controls) were analyzed. DBS and plasma samples demonstrated equivalent optical densities for detecting anti-HEV IgG. A highly significant correlation was observed between plasma and DBS sample absorbances (R(2) = 0.98; p

The application of plant growth-promoting rhizobacteria (PGPR) as vital components for plant growth promotion against biotic and abiotic stresses could be a promising strategy to improve crop production in areas vulnerable to increasing salinity. Here, we isolated Seventy-five endophytic bacteria from roots of healthy Oryza sativa grown in a saline environment of the southern coastal region of Bangladesh. The endophytes in a culture of ~108 CFU/ml showed arrays of plant growth-promoting (PGP) activities: phytohormone (Indole acetic acid) production (1.20–60.13 μg/ ml), nutrient (phosphate) solubilization (0.02–1.81 μg/ml) and nitrogen fixation (70.24–198.70 μg/ml). Four genomically diverse groups were identified namely, Enterobacter, Achromobacter, Bacillus, and Stenotrophomonas using amplified ribosomal DNA restriction analysis followed by their respective 16S rDNA sequence analyses with that of the data available in NCBI GenBank. These four specific isolates showed tolerance to NaCl ranging from 1.37 to 2.57 mol/L in the nutrient agar medium. Under a 200 mmol/L salt stress in vitro, the bacteria in a culture of 108 CFU/ml exhibited competitive exopolysaccharide (EPS) production: Stenotrophomonas (65 μg/ml) and Bacillus (28 μg/ml), when compared to the positive control, Pseudomonas spp. (23.65 μg/ml), a phenomenon ably supported by their strong biofilm-producing abilities both in a microtiter plate assay, and in soil condition; and demonstrated by images of the scanning electron microscope (SEM). Overall, the isolated endophytic microorganisms revealed potential PGP activities that could be supported by their biofilm-forming ability under salinity stress, thereby building up a sustainable solution for ensuring food security in coastal agriculture under changing climate conditions.

Iron (Fe) bioavailability to plants is reduced in saline soils; therefore, plants growing in arid soils face two major challenges for poor crop productivity: high salinity and Fe deficiency. Siderophore-producing plant growth-promoting rhizobacteria (PGPR) could be a promising alternative to chemical fertilizers that could tackle salt stress and Fe limitation in saline soils concurrently. Here, four salt-tolerant PGPR, isolated from the root area of salt-prone rice fields of Bangladesh were studied to evaluate their siderophore-producing ability. Bacillus aryabhattai MS3 exhibited the highest production, estimated at 60% and 43% under non-saline and saline (200 mM NaCl) conditions respectively. The expression of the entD gene, which is involved in the biosynthesis of siderophore was evidenced irrespective of saline states. Therefore, consideration of such salt-tolerant, siderophore-producing PGPR for producing biofertilizer could be an eco-friendly innovation for climate-smart agriculture in salinized soils with limited iron availability.

As far as comorbidity is concerned, cardiovascular diseases (CVD) appear to be accounted for the highest prevalence, severity, and fatality among COVID 19 patients. A wide array of causal links connecting CVD and COVID-19 baffle the overall prognosis as well as the efficacy of the given therapeutic interventions. At the centre of this puzzle lies ACE2 that works as a receptor for the SARS-CoV-2, and functional expression of which is also needed to minimize vasoconstriction otherwise would lead to high blood pressure. Furthermore, SARS-CoV-2 infection seems to reduce the functional expression of ACE2. Given these circumstances, it might be advisable to consider a treatment plan for COVID-19 patients with CVD in an approach that would neither aggravate the vasodeleterious arm of the renin-angiotensinogen-aldosterone system (RAAS) nor compromise the vasoprotective arm of RAAS but is effective to minimize or if possible, inhibit the viral replication. Given the immune modulatory role of Zn in both CVD and COVID-19 pathogenesis, zinc supplement to the selective treatment plan for CVD and COVID-19 comorbid conditions, to be decided by the clinicians depending on the cardiovascular conditions of the patients, might greatly improve the therapeutic outcome. Notably, ACE2 is a zinc metalloenzyme and zinc is also known to inhibit viral replication.

Gut microbiome serves as a critical interface between the host’s cells and the externalenvironment and plays important roles in a variety of health and disease states. Dysbiosis (disruption of healthy microbiome) and eubiosis (restoration of healthy microbiome) is a dynamic bidirectional transitional process which is influenced by a variety of intrinsic and extrinsic agents including heavy metal (HM) ions. Microbiome–HM ion interaction impacts the structure and function of the microbiome leading a variety of consequences such as alteration of the dynamics of pan-genomic metabolism (microbiome-host co-metabolism) and also metabolism and exacerbation or mitigation of toxic activity of HMs by gut microbiome. In this review, we attempted to summarize the current knowledge on the various aspects of heavy metal-gut microbiome interactions and the resultant outcomes of five major HMs, namely arsenic (As), mercury (Hg), chromium (Cr), cadmium (Cd), and lead (Pb), which have emerged as an important area of research.

As far as the comorbidity is concerned, cardiovascular diseases (CVD) appear to be accounted for the highest prevalence, severity, and fatality among COVID 19 patients. A wide array of causal links connecting CVD and COVID-19 baffle the overall prognosis as well as the efficacy of the given therapeutic interventions. At the centre of this puzzle lies ACE2 that works as a receptor for the SARS-CoV-2 and functional expression of which is also needed to minimize vasoconstriction otherwise would lead to high blood pressure. Furthermore, SARS-CoV-2 infection seems to reduce the functional expression of ACE2. Given these circumstances, it might be advisable to consider a treatment plan for COVID-19 patients with CVD in an approach that would neither aggravate the vasodeleterious arm of RAAS nor compromise the vasoprotective arm of RAAS but is effective to minimize or if possible, inhibit the viral replication. A zinc supplement to the selective treatment plan, to be decided by the clinicians depending on the cardiovascular conditions of the patients, is hereafter proposed that might greatly enhance the therapeutic outcome. Notably, ACE2 is a zinc metalloenzyme and zinc is also known to inhibit viral replication.

Objectives To determine IgG immune responses and hepatitis E virus (HEV) viral load, and to explore the associations with pregnancy. Methods A total of 121 HEV-infected women (57 pregnant, 64 non-pregnant) were analysed. Quantitative reverse transcription PCR (RT-qPCR) was done for 78 HEV IgM-positive patients to determine viral load, and Sanger sequencing was performed for 62 HEV-RNA-positive patients to confirm genotyping. ELISA was conducted to determine HEV antibody and avidity indices. Results The HEV genotype was identified as variant 1. Significant negative correlations were observed between log HEV copy number and log hepatitis E virus IgG antibody index in the late acute phase of jaundice for both pregnant women (r = −0.7971, p = 0.0002) and non-pregnant women (r = −0.9117, p = 0.0002). Pregnant women had significantly higher serum log viral copy numbers and lower IgG antibody indices than non-pregnant women in the late acute phase of HEV-induced jaundice (p = 0.0196 and p = 0.0303, respectively). Moreover, pregnant women with acute HEV hepatitis had higher cross-reactive IgG antibodies compared to the non-pregnant women (p = 0.0017). Five patients with HEV hepatitis died, of whom four were pregnant. Conclusions Pregnancy might be associated with higher viral loads and a lower IgG response in the HEV-induced late acute phase of jaundice.

Although Hepatitis E viral illness is usually self-limiting, higher rates of morbidity and mortality are frequently observed during pregnancy in South Asian countries including Bangladesh. Of the four common variants, hepatitis E virus genotype 1 is mainly prevalent in South Asian countries. Pregnant women usually suffer from a state of immunosuppression. It is yet to be known whether virus specific immunoglobulin G (IgG) immune responses have any association with the vulnerability of pregnant women to acute hepatitis with E virus. The study aimed to compare the viral load and IgG responses of hepatitis E-infected pregnant women with that of non-pregnant women with same infection. Real Time –quantitative reverse transcription Polymerase Chain Reaction and Sanger sequencing were performed to determine the viral load and genotype, respectively, whereas Enzyme Linked Immunosorbent Assay method was used to determine hepatitis E virus specific serum IgG antibody index along with IgG avidity index. Although significant negative correlations were observed between log viral copy number and log IgG antibody index in the late acute phases of jaundice for both pregnant (r= −0.7971, p=0.0002) and non-pregnant women (r= −0.9117, p=0.0002), serum log viral copy number of pregnant women was significantly higher than that of the non-pregnant counterpart (p=0.0196) in the late acute stage of jaundice. In addition, log hepatitis E virus IgG antibody index of pregnant women was significantly lower than the non-pregnant women in the late phase of jaundice induced by hepatitis E virus (p=0.0303). Moreover, pregnant women with acute hepatitis E had higher cross-reactive IgG than in the non-pregnant women (p=0.0017). All the patients got infected with hepatitis E virus were in Genotype 1 variety. The study demonstrates that virus-specific poor IgG responses might be responsible for vulnerability of pregnant women to acute hepatitis with hepatitis E virus.Author SummaryAcute hepatitis caused by hepatitis E virus (HEV) Genotype 1 is a public health problem in Asian countries and especially it poses a potential health threat to pregnant women causing 19% to 25% mortality, particularly in South Asian countries including Bangladesh. The study aimed to explore whether HEV IgG immune responses were compromised during pregnancy, which might contribute to higher viral load and disease severity. Accordingly, pregnant and non-pregnant women with acute hepatitis (clinically presented with nausea, loss of appetite and /or jaundice) were enrolled from different tertiary care hospitals in Dhaka city. All these patients were screened and hepatitis E were differentiated from other hepatitis (caused by A, B, C) using Enzyme Linked Immunosorbent Assay (ELISA) methods. HEV IgG antibody/avidity indices and viral loads were measured using ELISA and real time quantitative polymerase chain reaction (RT-qPCR), respectively. The study showed that pregnant women with acute hepatitis E had lower IgG indices with higher viral load than their non-pregnant counterpart. Overall, the study revealed that virus-specific poor IgG responses might render pregnant women vulnerable to acute hepatitis E of varying degree of severity which might be associated with higher viral load.

The salinity level in the coastal ecosystem and agricultural lands is being increased gradually due to the climate change effect, and Bangladesh is no exception to suffer salinity intrusion threatening its food security. In order to bring the salinity-affected lands under agriculture, the application of salt-tolerant, plant growth-promoting rhizobacteria (PGPR) as biofertilizer could be a method of choice. The current research reports the isolation of a salt-tolerant PGPR, identifi ed as Bacillus aryabhattai MS3 from a coastal rice fi eld of Bangladesh. Under laboratory condition, the strain showed profound plant growth-promoting activities: nitrogen fi xation, production of indole acetic acid (IAA), phosphorus solubilization and siderophore production under 200 mM salinity. While in soil, rice growth under non-saline condition was comparable in between biofertilizer-added and control pots, the scenario was statistically signifi cant when challenged with salts, 46% and 8% survival were recorded respectively. The PGPR supported the plants under salinity by increasing the availability of nutrients, accelerating IAA and chlorophyll production, enhancing proline accumulation, and decreasing malondialdehyde formation. The semi-quantitative reverse transcription-PCR demonstrated that the bacterium selectively up-regulated the plant expression of NHX1 gene under salinity, thereby conferring tolerance to salt stress. Overall, the application of salt-tolerant biofertilizer could be a non-transgenic innovation to support plant growth for coastal lands under changing climate conditions.

Objective To establish a suitable method of diagnosis of visceral leishmaniasis (VL) using peripheral blood, spleen or bone marrow aspirates. Methods Peripheral blood, bone marrow and spleen aspirate samples were collected from clinically suspected VL patients ( n = 26). A new PCR primer pair (MK1F/R) was designed targeting kinetoplast mini circle DNA sequences of Leishmania donovani , and Leishmania infantum , and was used to diagnose VL along with some other established primers for VL in polymerase chain reactions. Test was validated by comparing with several other diagnostic methods. Results The designed primer set showed 100% specificity and 98% sensitivity in detecting VL using blood samples, when compared with more invasive samples: bone marrow or spleen aspirates. Conclusions The newly designed primer MK1F/R could be a better alternative for PCR based diagnosis of VL using less invasive sample, peripheral blood instead of bone marrow or spleen aspirates.

Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a "delicate" balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)-a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.

Once believed to be a commensal bacteria,Enterococcus faeciumhas recently emerged as an important nosocomial pathogen worldwide. A recent outbreak ofE. faeciumunrevealed natural andin vitroresistance against a myriad of antibiotics namely ampicillin, gentamicin and vancomycin due to over-exposure of the pathogen to these antibiotics. This fact combined with the ongoing threat demands the identification of new therapeutic targets to combatE. faecium infections.In this present study, comparative proteome analysis, subtractive genomic approach, metabolic pathway analysis and additional drug prioritizing parameters were used to propose a potential novel drug targets forE. faecium strainDO. Comparative genomic analysis of Kyoto Encyclopedia of Genes and Genomes annotated metabolic pathways identified a total of 207 putative target proteins inE. faecium DOthat showed no similarity to human proteins. Among them 105 proteins were identified as essential novel proteins that could serve as potential drug targets through further bioinformatic approaches; such as-prediction of subcellular localization, calculation of molecular weight, and web-based investigation of 3D structural characterization. Eventually 19 non-homologous essential proteins ofE. faecium DOwere prioritized and proved to have the eligibility to become novel broad-spectrum antibiotic targets. Among these targets aldehyde-alcohol dehydrogenase was found to be involved in maximum pathways, and therefore, was chosen as novel drug target. Interestingly, aldehyde-alcohol dehydrogenase enzyme contains two domains namely acetaldehyde dehydrogenase and alcohol dehydrogenase, on which a 3D structure homology modeling andin silicomolecular docking were performed. Finally, eight molecules were confirmed as the most suitable ligands for aldehyde-alcohol dehydrogenase and hence proposed as the potential inhibitors of this target.In conclusion, being human non-homologous, aldehyde-alcohol dehydrogenase protein can be targeted for potential therapeutic drug development in future. However, laboratory based experimental research should be performed to validate our findingsin vivo.

Growth and productivity of rice are negatively affected by soil salinity. However, some salt-tolerant rhizosphere-inhabiting bacteria can improve salt resistance of plants, thereby augmenting plant growth and production. Here, we isolated a total of 53 plant-growth-promoting rhizobacteria (PGPR) from saline and non-saline areas in Bangladesh where electrical conductivity was measured as >7.45 and

Parasporal crystalline inclusion proteins of some Bacillus spp. are of paramount importance due to their insecticidal, nematocidal, and cancer cell killing capabilities. Here, we present a brief report of the complete genome sequence of Bacillus sp. BD59S, a bacterium that produced HeLa cell-killing parasporal crystalline inclusion proteins. From genome sequencing and assembly, we found that the bacterium has one circular chromosome and two large plasmids, pBTBD59S1 and pBTBD59S2. The size of the chromosome is 5283,933 bp with a 35.4% GC content, consisting of 5938 genes and 5550 protein-coding sequences (CDSs), 25 complete rRNAs (5S, 16S, 23S), 98 tRNAs, 5 ncRNAs, 260 pseudo-genes, and 356 subsystems. Complete plasmid sequence of pBTBD59S1 comprises a total size of 162,149 bp with 33.4% GC content, 192 CDSs, and 13 subsystems. The other plasmid pBTBD59S2, is 199,209 bp long with 32.9% GC content, 179 CDSs, and 11 subsystems. Analyses by NCBI microbial genome BLAST, phylogenetic genome tree, and BLAST ring image generator (BRIG) revealed that BD59S belongs to Bacillus cereus group, and is more close to B. thuringiensis. Further, the strain possesses 57.04 kDa and 54.42 kDa Cry protein-coding genes, which show significant similarities with cancer cell-killing parasporin proteins of B. thuringiensis strains. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-019-1849-7) contains supplementary material, which is available to authorized users.

Following an incidence of freshwater prawn Macrobrachium rosenbergii postlarvae (PL) mortality in hatcheries in summer 2012, samples from dead PL, rearing water and prawn feed from two south-west coastal districts of Bangladesh were collected to isolate, identify and characterize the agents causing PL mortality. Antibiogram profile of sixteen randomly selected bacteria, isolated from dead PL, that grew on TCBS, to 20 different antibiotics belonging to 12 major groups revealed that the drug resistance pattern varied from moderate (56% to the drugs: ciprofloxacin, cefotaxime, nitrofurantoin, kanamycin) to complete (to penicillin, ceftazidime and oxacillin) level. To identify the isolates, amplified rDNA restriction analysis (ARDRA) classified them in to four groups, and RAPD (randomly amplified polymorphic DNA) typing yielded nine different types of isolates within these four ARDRA groups. The 16S rDNA gene sequences identified that the groups were genotypically diverse belonging to the bacterial species: Enterobacter cloacae, Klebsiella pneumoniae, Exiguobacterium profundum and Enterococcus casseliflavus, respectively, that all demonstrated their killing potential to PLs in a simulated environment. The study therefore identified four different bacterial pathogens, one of which, Exiguobacterium profundum is reported for the first here in Bangladesh, that demand special consideration for disease management strategy.

The molecular basis of antagonistic activity of a number of probiotic bacteria was analyzed using plasmid curing method. Earlier, six bacteria having potential probiotic activity under laboratory conditions were screened from 96 isolates which were obtained from shrimp rearing environment from south-west coastal region of Bangladesh. Among the isolated probionts, five were subjected to plasmid curing method and three were found to harbor plasmids, as was revealed in an agarose gel electrophoresis. Curing of these plasmids demonstrated that the bacteria lost its antagonistic activity, indicating the activity could be plasmid-borne. The antagonistic activities of the rest two isolates however, were not plasmid-oriented as no plasmid was recovered from them. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15688 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 115-120, 2013

The use of chemotherapeutic agents has been questioned for disease management in shrimp aquaculture due to the emergence of drug-resistant bacteria and enduring residual effects in the environments. Instead, microbial interventions in sustainable aquaculture have been proposed, and among them, the use of probiotics as an alternative to antibiotics has gained considerable attention. Earlier, we short-listed nineteen isolates out of ninety six bacteria, isolated from shrimp ghers of coastal areas of Bangladesh that exhibited antagonistic potential against pathogenic vibrios, and non-hemolytic property, presumably indicating their harmless behavior in mammalian system at least in vitro . This prompted us to study their cytotoxic effect in vivo using brine shrimp Artemia franciscana. Six isolates were found having higher lethal values compared with others. Four of them, identified as Pseudomonas and Bacillus spp. exhibited the lowest inhibition against Artemia and were considered safe. Further, in a co-culture experiment it was evident that the isolated probiotic bacteria were shown to outcompete the growth of pathogenic Vibrio harveyi due to their antagonistic properties. The probionts can now therefore be tested in culture environment of Bangladesh in order to understand the effectiveness of microbial control of bacterial diseases in shrimp aquaculture. Keywords : Probiotic bacteria; Food safety; Shrimp aquaculture; Vibrios. © 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi:10.3329/jsr.v3i3.7750 J. Sci. Res. 3 (3), 659-668 (2011)

Extracts in organic solvents (namely methanol, ethanol, ethyl acetate and chloroform) of two medicinal plants - Achyranthes aspera and Cassia alata were evaluated for their antibacterial activities against Escherichia coli , Bacillus subtilis , Vibrio cholerae , Salmonella typhi and Staphylococcus aureus . These were carried out by taking the organic extracts of both the leaf and stem parts of the plants at a concentration of 5 mg/ml and their activities were recorded by estimating zones of inhibition as produced by disc-diffusion method on Mueller-Hinton agar media. While neither the leaf nor stem parts of A. aspera in any organic extractions showed antibacterial activity, the methanolic extracts of both the leaf and stem parts of C. alata exhibited antibacterial activity, but only to B. subtilis and S. typhi , and the corresponding MIC values of the leaf extracts were estimated as 1.25 and 1.5 mg/ml respectively. However, the ethanolic extracts of both the stem and leaf parts were found equally effective only to S. aureus (MIC= 1.25 mg/ml). The corresponding MBC values are reported. Keywords : Achyranthes aspera ; Cassia alata; Antibacterial. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i2.2298

Translation initiation in eukaryotes is a complicated process involving some of the largest cellular structures, the ribosomes, together with approx. 11 initiation factors, and a poorly characterized set of other proteins. The concerted action of all these components ultimately results in the formation of an 80 S ribosomal complex on the AUG codon of an mRNA, which is competent to start polypeptide production. In this brief overview, we describe the strategies developed by our laboratory to apply surface plasmon resonance (SPR)-based technology to the problem of elucidating kinetic aspects of substeps within the translation-initiation reaction. We then review how other groups have used similar SPR-based techniques to study related interactions.

Translation initiation is a key point of regulation in eukaryotic gene expression. 4E-binding proteins (4E-BPs) inhibit initiation by blocking the association of eIF4E with eIF4G, two integral components of the mRNA cap-binding complex. Phosphorylation of 4E-BP1 reduces its ability to bind to eIF4E and thereby to compete with eIF4G. A novel combination of biophysical and biochemical tools was used to measure the impact of phosphorylation and acidic side chain substitution at each potentially modulatory site in 4E-BP1. For each individual site, we have analyzed the effects of modification on eIF4E binding using affinity chromatography and surface plasmon resonance analysis, and on the regulatory function of the 4E-BP1 protein using a yeast in vivo model system and a mammalian in vitro translation assay. We find that modifications at the two sites immediately flanking the eIF4E-binding domain, Thr(46) and Ser(65), consistently have the most significant effects, and that phosphorylation of Ser(65) causes the greatest reduction in binding affinity. These results establish a quantitative framework that should contribute to understanding of the molecular interactions underlying 4E-BP1-mediated translational regulation.

Eukaryotic translation initiation involves recognition of the 5' end of cellular mRNA by the cap-binding complex known as eukaryotic initiation factor 4F (eIF4F). Initiation is a key point of regulation in gene expression in response to mechanisms mediated by signal transduction pathways. We have investigated the molecular interactions underlying inhibition of human eIF4E function by regulatable repressors called 4E-binding proteins (4E-BPs). Two essential components of eIF4F are the cap-binding protein eIF4E, and eIF4G, a multi-functional protein that binds both eIF4E and other essential eIFs. We show that the 4E-BPs 1 and 2 block the interaction between eIF4G and eIF4E by competing for binding to a dorsal site on eIF4E. Remarkably, binding of the 4E-BPs at this dorsal site enhances cap-binding via the ventral cap-binding slot, thus trapping eIF4E in inactive complexes with high affinity for capped mRNA. The binding contacts and affinities for the interactions between 4E-BP1/2 and eIF4E are distinct (estimated K(d) values of 10(-8) and 3x10(-9) for 4E-BP1 and 2, respectively), and the differences in these properties are determined by three amino acids within an otherwise conserved motif. These data provide a quantitative framework for a new molecular model of translational regulation.

Seventeen cases of invasive aspergillosis occurring since 1987 in apparently immunologically normal hosts have been reviewed: 9 of invasive sinus aspergillosis, 2 of isolated brain abscesses, 3 of pneumonia (1 in a patient who developed mediastinitis), 2 of lymph node aspergillosis, and 1 of osteomyelitis of the foot. Two of the 9 patients with sinus aspergillosis died; the rest were stable up to March 1993. They responded initially to combined surgical and medical therapy. Both patients with brain abscesses survived following surgery, but one had neurological sequelae. Both patients with pneumonia were well following therapy with amphotericin B; one also received itraconazole. The patient with mediastinitis died, but this disease was diagnosed late. The patients with lymph node involvement were lost to follow-up, as was the patient with osteomyelitis. Invasive aspergillosis may be common in Pakistan. Greater awareness would allow earlier diagnosis and therapy, thereby improving the outcome.

A total of 1106 stool samples collected from diarrhoea patients admitted to Dhaka hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh, during January–December 2008 were analysed for the presence of rotavirus-specific RNA by PAGE. The group B-specific RNA migration pattern was detected in 26 patients (2.4 %) and group A-specific pattern in 259 patients (23.4 %). Clinical data from group A and group B rotavirus-infected patients indicated that episodes did not differ much in the prevalence of diarrhoea, number of stools, outcome or differences in gender. However, abdominal pain was more common in group B rotavirus infections (36 vs 15 %, P=0.02) and the virus was responsible for more severe dehydration compared with group A-infected patients (12 vs 3 %, P=0.04). Sequence analyses of VP4, VP7 and NSP2 indicated that an Indian–Bangladeshi lineage of the virus, which is different from both the prototype (Chinese) lineage and from the animal group B rotaviruses, has been circulating in Bangladesh. Continuous monitoring of group B rotaviruses both in hospitals and in the community will be helpful to determine the true burden of group B rotaviruses.

The eukaryotic mRNA 3′ poly(A) tail and the 5′ cap cooperate to synergistically enhance translation. This interaction is mediated by the cap-binding protein eIF4E, the poly(A) binding protein (PABP), and eIF4G, a scaffolding protein that bridges between eIF4E and PABP to bring about the circularization of the mRNA. The translational repressor, Paip2 (PABP-interacting protein 2), inhibits translation by promoting the dissociation of PABP from poly(A). Here we report on the existence of an alternative mechanism by which Paip2 inhibits translation by competing with eIF4G for binding to PABP. We demonstrate that Paip2 can abrogate the translational activity of PABP, which is tethered to the 3′ end of the mRNA. Thus, Paip2 can inhibit translation by a previously unrecognized mechanism, which is independent of its ability to disrupt PABP–poly(A) interaction.

Shrimp export is the second largest exportable commodity in Bangladesh. However, frequent outbreaks of microbial diseases over the last few years challenged its prospect to flourish. The use of antimicrobial chemicals have led to the emergence of more virulent pathogens, with the eventual transfer of antimicrobial resistance to human pathogens. The use of beneficial bacteria (probiotics) to displace pathogens by competitive processes and to inhibit their proliferation is a better remedy than administering antibiotics. A good number of bacteria from rearing environment for shrimp aquaculture with potential probiotic activity in vitro have been isolated. Two approaches, the well diffusion method and co-culture experiments confirmed their probiotic nature. Their non-hemolytic property also ensured their safe mode for application in shrimp aquaculture. Once the effect is successfully translated in the culture ponds, this will be an eco-friendly, harmless approach to combat the disaster caused by bacterial infections without compromising the shrimp quality, thereby ensuring food safety in shrimp industries of Bangladesh. Key words: Probiotic bacteria, food safety, shrimp aquaculture, vibrios DOI: 10.3329/jbas.v33i1.2958 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 139-144, 2009

Bird flu, synonym of avian influenza (AI) caused by influenza A virus, become concern across the world for the possible incidence of the next human influenza pandemic. The latent danger of AI pandemic remains very real, though, the precise timing of occurrence and severity is uncertain. Each avian influenza type A (AIA) contains one of the 16 subtypes of haemagglutinin (HA) and 9 neuraminidases (NA) implicating theoretically 144 subtypes of AIA are possible in circulation, but only H1N1, H2N2 and H3N2 subtypes are documented for past pandemics in humans. In recent years H5N1, H7N3, H7N2, H7N7 and H9N2 are isolated from human samples, though H1N1 and H3N2 are still in circulation. Avian influenza viruses preferentially recognize receptor containing sialosugar chains terminating in sialic acid ?-2,3-galactose in bird, whereas, human preferentially contain ?-2,6-galactose subtype-receptor. To initiate a pandemic outbreak in human, the AIA viruses need alteration of receptor recognition specificity; and perfect match between HA and NA along with optimal cellular tropism. Cyclic nature of bird-flu emergence, and moreover, sporadic human incident reported around Asia and Europe in recent years anticipating a pandemic appearance of bird-flu in time to come. As we are on the edge of this alarming situation, AI prevention and containment can be considered under categories of surveillance, intervention, antiviral drugs, vaccination together with environment management issues.Keywords: Pandemic; Avian influenza; Genetic reassortment; Host specificity; Environment management DOI: http://dx.doi.org/10.3329/bjm.v25i1.4847Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 1-8

Keywords: Nipah virus; infection; outbreaks; prevention; awarenessDOI: http://dx.doi.org/10.3329/bjpath.v26i1.9147 BJPATH 2011; 26(1): 23-25

The immunoglobulin subclass responses to homologous lipopolysaccharide (LPS) and to cholera toxin (CT) in adult patients infected with Vibrio cholerae O1 and V. cholerae O139 were studied. LPS-specific antibody-secreting cells (ASC) of both the immunoglobulin A1 (IgA1) and IgA2 subclasses were seen, with the IgA1 ASC response predominating in both V. cholerae O1- and O139-infected patients. For antibodies in plasma, by day 11 after onset of disease, all V. cholerae O1- infected patients responded to homologous LPS with the IgA1 subclass ( P = 0.001), whereas fewer (68%) responded with the IgA2 subclass ( P = 0.007). About 89% of V. cholerae O139-infected patients responded with the IgA1 subclass ( P = 0.003), and only 21% responded with the IgA2 subclass (not significant [NS]). Both groups of cholera patients showed significant increases in LPS-specific IgG1, IgG2, and IgG3 antibodies in plasma. In feces, the response to homologous LPS occurred in both groups of patients with the IgA1 and IgA2 subclasses, with 55 to 67% of patients showing a positive response. V. cholerae O1- and O139-infected patients showed CT-specific ASC responses of the different IgG and IgA subclasses in the circulation, and the pattern followed the order IgG1 > IgA1 > IgG2 > IgA2, with low levels of IgG3 and IgG4 ASC. Plasma anti-CT antibody responses in all subclasses were seen by day 11 after onset of disease. Although there were no increases in CT-specific ASC of the IgG3 (NS) and IgG4 (NS) subtypes, there were significant increases of these two subclasses in plasma ( P ≤ 0.001). The response to CT in the fecal extracts was contributed to by both IgA1 and IgA2 isotypes, with 67 to 75% of the patients responding. Thus, the mucosa-derived ASC and fecal antibodies to LPS and CT were of both the IgA1 and IgA2 subclasses; in plasma, the contribution from IgA2 was lower. Very little difference in the B-cell responses to LPS and CT in the different subclasses was seen in the two groups of cholera patients. Vaccines against O1 and O139 cholera ideally should stimulate antibody subclasses that are likely to offer protection.