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1.
Md. Rezwan Molla Md. Motiar Rohman Mahmuda Binte Monsur Mirza Hasanuzzaman Lutful Hassan 《Phyton》2021,90(5):1425-1443
This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli (Capsicum annuum L.)
under drought genotypes through evaluating morphological, physiological, biochemical and stomatal parameters.
Twenty genotypes were evaluated for their genetic potential to drought stress tolerant at seedling stage. Thirty
days old seedlings were exposed to drought stress induced by stop watering for the following 10 days and rewatering for the following one week as recovery. Based on their survival performance, two tolerant genotypes
viz. BD-10906 and BD-109012 and two susceptible genotypes viz. BD-10902 and RT-20 were selected for studying
the oxidative stress tolerance mechanism. Drought reduced root and shoot length, dry weight, ratio, petiole weight
and leaf area in both tolerant and susceptible genotypes, and a higher reduction was observed in susceptible genotypes. Lower reduction of leaf area and photosynthetic pigments were also found in tolerant genotypes. Moreover,
tolerant genotypes showed higher recovery than susceptible genotypes after the removal of stress. A higher reduction
of relative water content (RWC) may cause an imbalance between absorbed and transpirated water in susceptible
genotypes. Higher accumulation of proline in tolerant genotypes might be helpful to for better osmotic maintenance
than that in susceptible genotypes. Tolerant genotypes showed higher antioxidant activity as they showed DPPH
radical scavenging percentage than the susceptible genotypes. Moreover, closer stomata in tolerant genotypes than
susceptible ones helped to avoid dehydration in tolerant genotypes. Thus, the above morphological, physiological,
biochemical and stomatal parameters helped to show better tolerance in chilli under drought stress. 相似文献
2.
Swapan Kumar Sarker Sanjay Saha Sonet Md. Mohasinul Haque Mahmuda Sharmin 《Ecological Research》2013,28(4):553-565
Tarap Hill Reserve, the largest upland reserve of Bangladesh, is situated along the Indo-Burma Biodiversity Hotspot. It encompasses the last remaining patches of natural vegetation in the Northeastern Tarap Mountain System and harbors 87 % of the nationally declared red-listed vascular plant species. Despite requiring high conservation priority, this is one of the least studied reserves in the tropics. In this study, we collected vegetation and soil (eight variables) data from 68 sample plots. We identified the tree communities by cluster analysis and verified them using the multi-response permutation procedure and detrended correspondence analysis. Species richness, diversity, and compositional similarity between the communities were also estimated. In total, 116 tree species representing 69 genera were recorded within the four identified tree community types. Finally, canonical correspondence analysis with associated Monte Carlo permutation tests (499 permutations) was performed to explore the patterns of variation in tree species distribution explained by the soil variables. Soil phosphorus, organic matter content, and pH were most closely correlated with tree compositional variation. Thus, conservation strategies that take into account variations in these influential soil factors may aid in the conservation of trees in the reserve. 相似文献
3.
Irin Parvin Abu Sadat Mohammad Sayeem Bin Shahid Subhasish Das Lubaba Shahrin Mst. Mahmuda Ackhter Tahmina Alam Soroar Hossain Khan Mohammod Jobayer Chisti John D. Clemens Tahmeed Ahmed David A. Sack Abu Syed Golam Faruque 《PLoS neglected tropical diseases》2021,15(9)
BackgroundAfter a multi-country Asian outbreak of cholera due to Vibrio cholerae serogroup O139 which started in 1992, it is rarely detected from any country in Asia and has not been detected from patients in Africa.Methodology/Principal findingsWe extracted surveillance data from the Dhaka and Matlab Hospitals of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) to review trends in isolation of Vibrio cholerae O139 in Bangladesh. Data from the Dhaka Hospital is a 2% sample of > 100,000 diarrhoeal patients treated annually. Data from the Matlab Hospital includes all diarrhoeal patients who hail from the villages included in the Matlab Health and Demographic Surveillance System. Vibrio cholerae O139 was first isolated in Dhaka in 1993 and had been isolated every year since then except for a gap between 2005 and 2008. An average of thirteen isolates was detected annually from the Dhaka Hospital during the last ten years, yielding an estimated 650 cases annually at this hospital. During the last ten years, cases due to serogroup O139 represented 0.47% of all cholera cases; the others being due to serogroup O1. No cases with serogroup O139 were identified at Matlab since 2006. Clinical signs and symptoms of cholera due to serogroup O139 were similar to cases due to serogroup O1 though more of the O139 cases were not dehydrated. Most isolates of O139 remained sensitive to tetracycline, ciprofloxacin, and azithromycin, but they became resistant to erythromycin starting in 2009.Conclusions/SignificanceCholera due to Vibrio cholerae serogroup O139 continues to cause typical cholera in Dhaka, Bangladesh. 相似文献
4.
Rubella Virus (RUBV) is a common cause of childhood rash and fever in non-immunized populations, and its public health importance
relates to teratogenic effects of primary rubella infection in women with early pregnancy. Infection of the fetus may lead
to congenital rubella syndrome (CRS). This work aimed to assess the degree of risk associated in acquiring rubella virus infection
by the women during pregnancy and developing CRS among their children in Bangladesh. The study population (n = 275) included pregnant mothers (15–38 years) from various socioeconomic backgrounds attending a women health care based
hospital. All subjects were personally interviewed, clinically examined and a standardized questionnaire was filled up for
each of them. From each participant 3 ml blood was taken and serum was separated. Commercially available ELISA kit was used
for the qualitative and quantitative determination of IgM and IgG class antibodies against RUBV in collected serum samples.
209 women were found to contain detectable level of antiRUBV IgG antibodies, but did not possess IgM antibodies against rubella.
Only 9% participants were vaccinated previously against rubella virus among the whole antenatal population studied. Ninety-two
percent of these vaccinated pregnant women contained serum anti-rubella IgG antibody which was significantly (P = 0.05) higher than that of the nonvaccinated study population (75%). Pregnant women from lower middle and poor socioeconomic
class had significantly (P = 0.05) more intra uterine growth retardation (IUGR) of fetus than the upper middle class. 20% of the women of child bearing
age examined in this work were not yet exposed to RUBV and at risk of acquiring this virus during pregnancy and subsequently
transmitting the virus to the fetus. Our work demonstrates rubella attack rate among antenatal population in Bangladesh as
14.5 in 1000 during pregnancy. A proper and reliable vaccination policy against rubella virus is not yet adopted at the national
level in many developing countries including Bangladesh. This work identifies the requirement of detailed study for the identification
of intrauterine rubella infection and its related influence on perinatal morbidity and mortality. Thorough epidemiological
studies are also considered necessary prior to the development and acceptance of national immunization program against rubella
virus in Bangladesh. 相似文献
5.
Islam MS Mahmuda S Morshed MG Bakht HB Khan MN Sack RB Sack DA 《Canadian journal of microbiology》2004,50(2):127-131
Recently, a new strain of cholera, Vibrio cholerae O139, has emerged as an epidemic strain, but there is little information about its environmental reservoir. The present investigation was aimed to determine the role of cyanobacteria in the persistence of V. cholerae O139 in microcosms. An environmental isolate of V. cholerae O139 and three cyanobacteria (Anabaena sp., Nostoc sp., and Hapalosiphon sp.) were used in this study. Survival of culturable V. cholerae O139 in microcosms was monitored using taurocholate-tellurite gelatin agar medium. Viable but nonculturable V. cholerae O139 were detected using a fluorescent antibody technique. Vibrio cholerae O139 could be isolated for up to 12 days in a culturable form in association with cyanobacteria but could not be isolated in the culturable form after 2 days from control water without cyanobacteria. The viable but nonculturable V. cholerae O139 could be detected in association with cyanobacteria for up to 15 months. These results, therefore, suggest that cyanobacteria can act as a long-term reservoir of V. cholerae O139 in an aquatic environment. 相似文献
6.
Escherichia coli O157:H7 is considered among the most important recently emerged food-borne bacteria causing severe hemorrhagic diarrhea. Antibiotic treatment is not recommended as a prospective curative agent against this pathogen. Therefore, potency assessment of the local lytic phage isolates infecting E. coli O157:H7 as an alternate remedy to antibiotics was the principal concern of this study. Phage isolates against E. coli O157:H7 were checked by polymerase chain reaction for the presence of the virulence genes stx1 and stx2, and the safe phages were further screened in vitro for their capacity as biocontrol agents. Two bacteriophage strains, namely PAH6 and P2BH2, that had expressed potential antibacterial activity (P?< 0.05) in vitro were selected for in vivo testing in ligated rabbit ileal loop models. Both phage isolates were capable of decreasing fluid accumulation in rabbit ileal loops along with reducing bacterial growth (r = 0.992). Combined application of the phages was found most satisfactory, reducing seven?log cycles of bacterial growth. Consistent results in both in vivo and in vitro experiments demonstrate the applicability of bacteriophages as a rapid response tool against E.?coli O157:H7. To our knowledge, this is the first successful application of the rabbit ileal loop test for therapeutic evaluation of bacteriophages. 相似文献
7.
Taslima T. Lina Bijay K. Khajanchi Ishrat J. Azmi Mohammad Aminul Islam Belal Mahmood Mahmuda Akter Atanu Banik Rumana Alim Armando Navarro Gabriel Perez Alejandro Cravioto Kaisar A. Talukder 《PloS one》2014,9(10)
Background
Resistance to cephalosporins in Enterobacteriaceae is mainly due to the production of extended-spectrum beta-lactamase (ESBL). Little is known about ESBL-producing bacteria in Bangladesh. Therefore, the study presents results of phenotypic and molecular characterization of ESBL-producing Escherichia coli from hospitals in Bangladesh.Methods
A total of 339 E. coli isolated from patients with urinary tract and wound infections attending three different medical hospitals in urban and rural areas of Bangladesh between 2003–2007 were screened for ESBL-production by the double disk diffusion test. Isolates with ESBL-phenotype were further characterized by antibiotic susceptibility testing, PCR and sequencing of different β-lactamase and virulence genes, serotyping, and XbaI-macrorestriction followed by pulsed-field gel electrophoresis (PFGE).Results
We identified 40 E. coli with ESBL phenotype. These isolates were resistant to ceftriaxone, ceftazidime, cefotaxime, aztreonam, cefepime, and nalidixic acid but remained susceptible to imipenem. All but one isolate were additionally resistant to ciprofloxacin, and 3 isolates were resistant to cefoxitin. ESBL genes of blaCTX-M-1-group were detected in all isolates; blaTEM-type and blaOXA-1-type genes were detected in 33 (82.5%) and 19 (47.5%) isolates, respectively. Virulence genes that are present in diarrhoeagenic E. coli were not found. Class-1 integron was present in 20 (50%) isolates. All the ESBL-producing E. coli isolates harbored plasmids ranging between 1.1 and 120 MDa. PFGE-typing revealed 26 different pulsotypes, but identical pulsotype showed 6 isolates of serotype O25:H4.Conclusion
The prevalence of multidrug-resistant ESBL-producing E. coli isolates appears to be high and the majority of the isolates were positive for bla CTX-M. Although there was genetic heterogeneity among isolates, presence of a cluster of isolates belonging to serotype O25:H4 indicates dissemination of the pandemic uropathogenic E. coli clone in Bangladesh. 相似文献8.
Farzana Islam Rume Alessia Affuso Luigina Serrecchia Valeria Rondinone Viviana Manzulli Emanuele Campese Pietro Di Taranto Paritosh Kumar Biswas Chowdhury Rafiqul Ahsan Mahmuda Yasmin Antonio Fasanella Martin Hugh-Jones 《PloS one》2016,11(4)
In Bangladesh, anthrax, caused by the bacterium Bacillus anthracis, is considered an endemic disease affecting ruminants with sporadic zoonotic occurrences in humans. Due to the lack of knowledge about risks from an incorrect removal of infected carcasses, the disease is not properly monitored, and because of the socio-economic conditions, the situation is under-reported and under-diagnosed. For sensitive species, anthrax represents a fatal outcome with sudden death and sometimes bleeding from natural orifices. The most common source of infection for ruminants is ingestion of spores during grazing in contaminated pastures or through grass and water contaminated with anthrax spores. Domestic cattle, sheep and goats can also become infected through contaminated bone meal (used as feed) originating from anthrax-infected carcasses. The present investigation was conducted to isolate B. anthracis organisms from 169 samples (73 soil, 1 tissue, 4 bone and 91 bone meal samples) collected from 12 different districts of Bangladesh. The sampling was carried out from 2012 to 2015. Twelve samples resulted positive for B. anthracis. Biomolecular analyses were conducted starting from the Canonical Single Nucleotide Polymorphism (CanSNP) to analyze the phylogenetic origin of strains. The analysis of genotype, obtained through the Multiple Locus Variable Number Tandem Repeat Analysis (MLVA) with the analysis of 15 Variable Number Tandem Repeats (VNTR), demonstrated four different genotypes: two of them were previously identified in the district of Sirajganj. The sub-genotyping, conducted with Single Nucleotide Repeats analysis, revealed the presence of eight subgenotypes. The data of the present study concluded that there was no observed correlation between imported cattle feed and anthrax occurrence in Bangladesh and that the remarkable genetic variations of B. anthracis were found in the soil of numerous outbreaks in this country. 相似文献
9.
The distribution of coliphages infecting different Escherichia coli virotypes (EHEC, EIEC, EPEC, ETEC) and an avirulent strain (K-12) in sewage system of a hospital and a sewage treatment plant
(STP) was investigated by culture-based agar overlay methods. Coliphages were found in all the samples except stool dumping
site in the sewage system of the hospital and lagoon of the STP. Bacteriophage count (pfu/ml) infecting E. coli strains showed the following ascending pattern (EHEC < EIEC < EPEC < ETEC < E coli K-12) in all the collected samples except one. Phages capable of infecting avirulent E. coli K-12 strains were present in the highest number among all the examined locations. Phages specific for E. coli K-12 presented high diversity in plaque size on the bacterial lawn. Virulent E. coli specific coliphages rarely produced plaques with diameter of 1–2 mm or over. Conventional agar overlay method was found to
be not satisfactory for phage community analysis from primary stool dumping site of the hospital, probably due to the presence
of high concentration of antimicrobial substances. The gradual decrease seen in the five groups of coliphage quantity with
the ongoing treatment process and then the absolute absence of coliphages in the outlet of the examined treatment plant is
indicative of the usefulness of the treatment processes practiced there. 相似文献
10.
Mustafizur Rahman Mohammad Jubair Meer T. Alam Thomas A. Weppelmann Taj Azarian Marco Salemi Ilya A. Sakharuk Mohammed H. Rashid Judith A. Johnson Mahmuda Yasmin J. Glenn Morris Jr Afsar Ali 《PloS one》2014,9(11)
In October, 2010, epidemic cholera was reported for the first time in Haiti in over 100 years. Establishment of cholera endemicity in Haiti will be dependent in large part on the continued presence of toxigenic V. cholerae O1 in aquatic reservoirs. The rugose phenotype of V. cholerae, characterized by exopolysaccharide production that confers resistance to environmental stress, is a potential contributor to environmental persistence. Using a microbiologic medium promoting high-frequency conversion of smooth to rugose (S–R) phenotype, 80 (46.5%) of 172 V. cholerae strains isolated from clinical and environmental sources in Haiti were able to convert to a rugose phenotype. Toxigenic V. cholerae O1 strains isolated at the beginning of the epidemic (2010) were significantly less likely to shift to a rugose phenotype than clinical strains isolated in 2012/2013, or environmental strains. Frequency of rugose conversion was influenced by incubation temperature and time. Appearance of the biofilm produced by a Haitian clinical rugose strain (altered biotype El Tor HC16R) differed from that of a typical El Tor rugose strain (N16961R) by confocal microscopy. On whole-genome SNP analysis, there was no phylogenetic clustering of strains showing an ability to shift to a rugose phenotype. Our data confirm the ability of Haitian clinical (and environmental) strains to shift to a protective rugose phenotype, and suggest that factors such as temperature influence the frequency of transition to this phenotype. 相似文献