| 1. |
- Uddin, Md Bashir, et al.
(författare)
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Molecular Detection of Colistin Resistance mcr-1 Gene in Multidrug-Resistant Escherichia coli Isolated from Chicken
- 2022
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Ingår i: Antibiotics. - : MDPI AG. - 2079-6382. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Zoonotic and antimicrobial-resistant Escherichia coli (hereafter, E. coli) is a global public health threat which can lead to detrimental effects on human health. Here, we aim to investigate the antimicrobial resistance and the presence of mcr-1 gene in E. coli isolated from chicken feces. Ninety-four E. coli isolates were obtained from samples collected from different locations in Bangladesh, and the isolates were identified using conventional microbiological tests. Phenotypic disk diffusion tests using 20 antimicrobial agents were performed according to CLSI-EUCAST guidelines, and minimum inhibitory concentrations (MICs) were determined for a subset of samples. E. coli isolates showed high resistance to colistin (88.30%), ciprofloxacin (77.66%), trimethoprim/sulfamethoxazole (76.60%), tigecycline (75.53%), and enrofloxacin (71.28%). Additionally, the pathotype eaeA gene was confirmed in ten randomly selected E. coli isolates using primer-specific polymerase chain reaction (PCR). The presence of mcr-1 gene was confirmed using PCR and sequencing analysis in six out of ten E. coli isolates. Furthermore, sequencing and phylogenetic analyses revealed a similarity between the catalytic domain of Neisseria meningitidis lipooligosaccharide phosphoethanolamine transferase A (LptA) and MCR proteins, indicating that the six tested isolates were colistin resistant. Finally, the findings of the present study showed that E. coli isolated from chicken harbored mcr-1 gene, and multidrug and colistin resistance. These findings accentuate the need to implement strict measures to limit the imprudent use of antibiotics, particularly colistin, in agriculture and poultry farms.
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| 2. |
- Hasan, Mahmudul, et al.
(författare)
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Solution Structure of the dATP-Inactivated Class I Ribonucleotide Reductase From Leeuwenhoekiella blandensis by SAXS and Cryo-Electron Microscopy
- 2021
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The essential enzyme ribonucleotide reductase (RNR) is highly regulated both at the level of overall activity and substrate specificity. Studies of class I, aerobic RNRs have shown that overall activity is downregulated by the binding of dATP to a small domain known as the ATP-cone often found at the N-terminus of RNR subunits, causing oligomerization that prevents formation of a necessary alpha(2)beta(2) complex between the catalytic (alpha(2)) and radical generating (beta(2)) subunits. In some relatively rare organisms with RNRs of the subclass NrdAi, the ATP-cone is found at the N-terminus of the beta subunit rather than more commonly the alpha subunit. Binding of dATP to the ATP-cone in beta results in formation of an unusual beta(4) tetramer. However, the structural basis for how the formation of the active complex is hindered by such oligomerization has not been studied. Here we analyse the low-resolution three-dimensional structures of the separate subunits of an RNR from subclass NrdAi, as well as the alpha(4)beta(4) octamer that forms in the presence of dATP. The results reveal a type of oligomer not previously seen for any class of RNR and suggest a mechanism for how binding of dATP to the ATP-cone switches off catalysis by sterically preventing formation of the asymmetrical alpha(2)beta(2) complex.
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| 3. |
- Hasan, Mahmudul, et al.
(författare)
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The structure of human dermatan sulfate epimerase 1 emphasizes the importance of C5-epimerization of glucuronic acid in higher organisms
- 2021
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 12:5, s. 1869-1885
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Tidskriftsartikel (refereegranskat)abstract
- Dermatan sulfate epimerase 1 (DS-epi1, EC 5.1.3.19) catalyzes the conversion of d-glucuronic acid to l-iduronic acid on the polymer level, a key step in the biosynthesis of the glycosaminoglycan dermatan sulfate. Here, we present the first crystal structure of the catalytic domains of DS-epi1, solved at 2.4 Å resolution, as well as a model of the full-length luminal protein obtained by a combination of macromolecular crystallography and targeted cross-linking mass spectrometry. Based on docking studies and molecular dynamics simulations of the protein structure and a chondroitin substrate, we suggest a novel mechanism of DS-epi1, involving a His/double-Tyr motif. Our work uncovers detailed information about the domain architecture, active site, metal-coordinating center and pattern of N-glycosylation of the protein. Additionally, the structure of DS-epi1 reveals a high structural similarity to proteins from several families of bacterial polysaccharide lyases. DS-epi1 is of great importance in a range of diseases, and the structure provides a necessary starting point for design of active site inhibitors.
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| 4. |
- Joardder, Mohammad U. H., et al.
(författare)
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Significance of Glass Transition Temperature of Food Material in Selecting Drying Condition: An In-Depth Analysis
- 2023
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Ingår i: Food reviews international (Print). - : TAYLOR & FRANCIS INC. - 8755-9129 .- 1525-6103.
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Forskningsöversikt (refereegranskat)abstract
- Drying is a complicated phenomenon involving a combination of transport, deformation, and chemical kinetics. It is an energy intensive lengthy process and results in deterioration of food quality. The glass transition temperature (GTT) significantly affects the internal mass transfer mechanism and hence significantly affects the drying kinetics. Moreover, the rheological and transport characteristics of food materials are remarkably impacted by GTT, which has an influence on the energy consumption and quality of food products during drying. Similarly, molecular weight and drying conditions also affect the GTT. This comprehensive review uncovers the fundamental understanding of GTT and demonstrates its crucial relationship with physio-structural and transport properties of food items. It has been demonstrated that a clear understanding of the glass transition temperature may help in determining appropriate drying conditions while ensuring great food quality.
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| 5. |
- Paul, S. I., et al.
(författare)
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Bioprospecting potential of marine microbial natural bioactive compounds
- 2021
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Ingår i: Journal of Applied Biotechnology Reports. - 2322-1186. ; 8:2, s. 96-108
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Tidskriftsartikel (refereegranskat)abstract
- The ocean is considered to be an immense reservoir of biological and microbial diversity on the planet. In marine biospheres, microbial communities are ecologically significant as intermediaries of energy. By decomposing the dead as well as decaying organic matter with the assistance of microbial communities, it plays an indispensable role in nutrient regeneration cycles of marine ecosystems. Marine environments associated with microorganisms such as bacteria, fungi and bacterial virus have renowned potential to produce novel bioactive natural products and chemically diverse secondary metabolites like antibiotics, antifungal, antiviral, antitumor, anticancer and also different hydrolyzing enzymes, namely, protease, lipase, amylase, chitinase, etc. Hence, the bioprospecting for these compounds is of greater importance. Numerous effective and efficient application of marine microbial metabolites contribute to the fields of pharmaceuticals, biotechnological, agricultural, cosmetics industries, and so on. This review attempts to summarize the present status of bioprospecting marine microorganisms and their role in natural product discovery. © 2021 The Author(s).
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| 6. |
- Paul, S. I., et al.
(författare)
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Fish Biodiversity, Threat Status and Conservation Significance of the Jamuna River, Bangladesh
- 2021
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Ingår i: Ribarstvo, Croatian Journal of Fisheries. - : Walter de Gruyter GmbH. - 1330-061X .- 1848-0586. ; 79:4, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- The present survey aimed to explore the fish fauna diversity, abundance and conservation status in the Jamuna River, a tributary of the River Brahmaputra, Bangladesh. During the study period from November 2018 to October 2019, a total of 55 species of fish were recorded, belonging to 6 orders, 20 families and 41 genera from the five selected stations near the river. Orders Cypriniformes and Siluriformes were recorded as the dominant group in the fish fauna community that comprises 34.55% and 30.91% of total species, respectively. Various types of Small Indigenous Species (SIS) and a total of 26 International Union for Conservation of Nature (IUCN) red-listed species were recorded. Population indices, viz. Shannon-Weaver index (H), Simpson's dominance index (D), Simpson's index of diversity (1-D), Margalef's index (d) and Evenness (E), were applied to demonstrate the species diversity, richness and evenness of fish, and their overall values were 1.28-1.48, 0.26-0.33, 0.67-0.74, 1.22-1.46 and 0.77-0.86, respectively. To sustain the prospect of fisheries biodiversity in the Jamuna River of Bangladesh, different fish management and conservation plan of action specifically establishing and maintaining fish sanctuaries, banning indiscriminate fishing and the use of destructive fishing gears for the protection of the breeding and nursery grounds of fish should be taken into consideration with utmost priority. © 2021 Sulav Indra Paul et al., published by Sciendo.
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| 7. |
- Uddin, Md Bashir, et al.
(författare)
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Multidrug Antimicrobial Resistance and Molecular Detection of mcr-1 Gene in Salmonella Species Isolated from Chicken
- 2021
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Ingår i: Animals. - : MDPI. - 2076-2615. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Colistin (polymyxin E) is widely used in animal and human medicine and is increasingly used as one of the last-resort antibiotics against Gram-negative bacilli. Due to the increased use of colistin in treating infections caused by multidrug-resistant Gram-negative bacteria, resistance to this antibiotic ought to be monitored. The study was undertaken to elucidate the molecular mechanisms, genetic relationships and phenotype correlations of colistin-resistant isolates. Here, we report the detection of the mcr-1 gene in chicken-associated Salmonella isolates in Bangladesh and its in-silico functional analysis. Out of 100 samples, 82 Salmonella spp. were isolated from chicken specimens (liver, intestine). Phenotypic disc diffusion and minimum inhibitory concentration (MIC) assay using different antimicrobial agents were performed. Salmonella isolates were characterized using PCR methods targeting genus-specific invA and mcr-1 genes with validation for the functional analysis. The majority of the tested Salmonella isolates were found resistant to colistin (92.68%), ciprofloxacin (73.17%), tigecycline (62.20%) and trimethoprim/sulfamethoxazole (60.98%). When screened using PCR, five out of ten Salmonella isolates were found to carry the mcr-1 gene. One isolate was confirmed for Salmonella enterica subsp. enterica serovar Enteritidis, and other four isolates were confirmed for Salmonella enterica subsp. enterica serovar Typhimurium. Sequencing and phylogenetic analysis revealed a divergent evolutionary relationship between the catalytic domain of Neisseria meningitidis lipooligosaccharide phosphoethanolamine transferase A (LptA) and MCR proteins, rendering them resistant to colistin. Three-dimensional homology structural analysis of MCR-1 proteins and molecular docking interactions suggested that MCR-1 and LptA share a similar substrate binding cavity, which could be validated for the functional analysis. The comprehensive molecular and in-silico analyses of the colistin resistance mcr-1 gene of Salmonella spp. of chicken origin in the present study highlight the importance of continued monitoring and surveillance for antimicrobial resistance among pathogens in food chain animals.
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