Mungroo, Mohammad RidwaneKhan, Naveed AhmedAnwar, AyazSiddiqui, Ruqaiyyah...
11页
查看更多>>摘要：Pathogenic free-living amoebae are known to cause fatal central nervous system infections with extremely high mortality rates. High selectivity of the blood-brain barrier hampers delivery of drugs and untargeted delivery of drugs can cause severe side effects. Nanovehicles can be used for targeted drug delivery across the blood-brain barrier. Inorganic nanoparticles have been explored as carriers for various biomedical applications and can be modified with various ligands for efficient targeting and cell selectivity while lipid-based nanoparticles have been extensively used in the development of both precision and colloidal nanovehicles. Nanomicelles and polymeric nanoparticles can also serve as nanocarriers and may be modified so that responsiveness of the nanoparticles and release of the loads are linked to specific stimuli. These nanoparticles are discussed here in the context of the treatment of central nervous system infections due to pathogenic amoebae. It is anticipated that these novel strategies can be utilized in tandem with novel drug leads currently in the pipeline and yield in the development of much needed treatments against these devastating parasites.
查看更多>>摘要：Introduction Serratia marcescens has attracted increasing attention worldwide as a neglected opportunistic pathogen of public health concern, especially due to its antimicrobial resistance features, which usually cause nosocomial infections in immunocompromised or critically ill patients. Methods In our study, four carbapenem-resistant Serratia marcescens (CRSM) clinical isolates were characterized in our hospital from February 2018 to May 2018. The conjugation experiment confirmed the transferability of the carbapenem resistance gene. The types of carbapenem resistance genes were detected by PCR. The homology of the strains was analysed by pulsed field gel electrophoresis (PFGE). The characteristics of the plasmid and environment of carbapenem resistance genes were analysed after whole genome sequencing was performed. Then, we compared the amino acid sequence of the replication initiation protein and constructed a dendrogram by the neighbour-joining method. Results All four isolates showed carbapenem resistance conferred by a blaKPC-2-harbouring plasmid. They had exactly the same bands confirmed by PFGE and were defined as the homologous strains. The blaKPC-2 genes in all of the isolates were located in a 42,742 bp plasmid, which was located in the core region of antibiotic resistance and was composed of Tn3 family transposons, recombinant enzyme genes, ISKpn6 and ISKpn27. The core region of antibiotic resistance formed a 'Tn3-ISKpn6-blaKPC-ISKpn27-Tn3' structure, which was an independent region as a movable element belonging to transposon Tn6296 and its derivatives. The plasmid had a similar skeleton to incX6 plasmids and a similar amino acid sequence to the replication initiation protein. The plasmid was defined as an untypeable blaKPC-2-harbouring plasmid named the 'IncX6-like' plasmid. Conclusion The four CRSM isolates were mainly clonally disseminated with a blaKPC-2-harbouring plasmid in our hospital. The pKPC-2-HENAN1602 plasmid (CP047392) in our study was first reported in Serratia marcescens, which belongs to an untypeable group named the 'IncX6-like' plasmid. The carbapenem-resistant gene structure surrounding blaKPC-2 as a sole accessory module can be acquired by horizontal gene transfer and might lead to serious nosocomial infection.
查看更多>>摘要：Biofilm-associated Candida infections threaten public health and show high mortality. The drugs used in treatment are very limited due to reasons such as toxicity, low efficacy, and drug resistance, and new alternatives are needed. The use of natural products of plant origin in the biofilm management draws attention. CA (cinnamaldehyde, cinnamic aldehyde, or 3-phenyl-2-propenal) is an essential oil component that can also inhibit mold growth and mycotoxin production. However, there are some limitations in its use due to its poor solubility and volatility in water. Recently, the combination of natural components and nanoparticle-based drug delivery systems shows positive results. In this study, the effects of PLGA (poly(DL-lactide-co-glycolide)) nanoparticles arrested with CA (CA-PLGA NPs) on C. albicans planktonic and biofilm forms (prebiofilm and postbiofilm) were investigated. According to the results, the amount of active ingredient loaded in CA-PLGA NPs is much lower than the free CA and a strong antifungal effect was obtained even at this rate. Also, the postbiofilm application is more effective than prebiofilm application. PLGA NPs can also be a useful carrier for other essential oils, and their potential in various antifungal, antibiofilm, and biomedical applications should be investigated.
查看更多>>摘要：The emerging situation of Salmonella enterica subsp. enterica serovar Infantis (S. Infantis) in Turkey was investigated in terms of virulence genes and mobile genetic elements such as Salmonella genomic island 1 (SGI1) and class 1 (C1) integron to see whether increased multidrug resistance (MDR) and ability to cause human cases is a consequence of their possession. Screening of SGI1 (and its variants) and C1 integrons was done with conventional PCR, while screening of gene cassettes and virulence genes was conducted with real-time PCR for 70 S. Infantis isolates from poultry products. SGI1 or its variants were not detected in any of the isolates. Sixty-eight of 70 isolates were detected to carry one C1 integron of size 1.0 kb. These integrons were detected to carry ant(3 '')-Ia gene cassette explaining the streptomycin/spectinomycin resistance. Sequence analysis of gene cassettes belongs to four representing isolates which showed that, although their difference in isolation date and place, genetically, they are 99.9% similar. Virulence gene screening was introduced as genotypic virulence profiles. The most dominant profile for S. Infantis isolates, among twelve genes, was gatC-tcfA, which are known to be related to colonization at specific hosts. This study revealed the high percentage of C1 integron possession in S. Infantis isolates from poultry products in Turkey. It also showed the potential of S. Infantis strains to be resistant to more antimicrobial drugs. Moreover, a dominant profile of virulence genes that are uncommon for non-typhoidal Salmonella (NTS) serovars was detected, which might explain the enhanced growth at specified hosts.
查看更多>>摘要：Accumulating evidence has pointed out that the gut-brain axis plays important roles in the etiology of autism spectrum disorder (ASD). Gut dysbiosis was reported in both ASD human patients and animal models. Dip2a was identified as a human ASD candidate gene. Deletion of Dip2a led to dendritic spine dysfunction and autistic-like behaviors in mice. To further investigate if Dip2a deletion leads to gut dysbiosis, we used 16S rDNA sequencing to study the gut microbiota in Dip2a KO mice. In both co-housed and separated breeding conditions, deletion of Dip2a could affect the gut microbiome composition. The probiotic bacteria, Lactobacillus and Bifidobacterium, became less abundant, while some potentially harmful bacteria, Alistipes, Lachnospiraceae_NK4A136_group, Clostridium, Desulfovibrio, and Enterorhabdus, became more abundant. We further found that probiotic treatment could help to reconstitute the gut microbiome composition in Dip2a KO mice. Altogether, these data showed DIP2A is required for the proper composition of gut microbiota, and the probiotics have potential roles in rectifying the gut microbiota in Dip2a KO mice.
查看更多>>摘要：Vincristine, one of the major vinca alkaloid of Catharanthus roseus (L.) G. Don. (Apocynaceae), was enhanced under in vitro callus culture of C. roseus using fungal extract of an endophyte Alternaria sesami isolated from the surface-sterilized root cuttings of C. roseus. Vindoline, a precursor molecule for vincristine production, was detected for the first time in the fungal endophyte A. sesami which was used as a biotic elicitor in this study to enhance vincristine content in the C. roseus callus. It was identified using high-performance liquid chromatography and mass spectroscopy techniques by matching retention time and mass data with reference molecule. Supplementing the heat sterilized A. sesami endophytic fungal culture extract into the callus culture medium of C. roseus resulted in the enhancement of vincristine content in C. roseus callus by 21.717% after 105-day culture.
查看更多>>摘要：The marine bacterial exopolysaccharides (EPS) have transfigured the biotech sector with their myriad applications and prospects. This work was carried out to characterize and analyze the functional and biochemical properties of an EPS (EPS-DR3A) produced by a marine bacterium, Pseudoalteromonas sp. YU16-DR3A. The bacterium was cultured in Zobell marine broth for the production of EPS. The extracted EPS designated as EPS-DR3A was composed of 69% carbohydrates and 7.6% proteins with a molecular weight of 20 kDa. FT-IR spectra showed the presence of different functional groups. The monosaccharide analysis performed using GC-MS showed the presence of fucose, erythrotetrose, ribose, and glucose as monomers. EPS-DR3A showed excellent emulsifying activity against the tested hydrocarbons and food oils with stable emulsions. Rheological analysis of EPS-DR3A revealed the pseudoplastic behavior. The EPS-DR3A displayed good thermal stability with a degradation temperature of 249 degrees C and a melting point at 322 degrees C. Further, it had the ability to scavenge DPPH and nitric oxide free radicals with good total antioxidant activity. The in vitro biocompatibility study of EPS-DR3A showed high degree of biocompatibility with human dermal fibroblast cells at the tested concentrations. Taken together, the findings such as thermostability, emulsifying activity, pseudoplasticity, antioxidant activity, and biocompatibility of EPS-DR3A make this biomolecule an important candidate for a wide range of biomedical applications.
查看更多>>摘要：Uropathogenic E. coli (UPEC) strains exhibit different levels of biofilm formation that help adhesion of the bacteria to uroepithelial cells. We investigated the genetic diversity and virulence-associated genes (VAGs) of biofilm-producing UPEC. A collection of 107 biofilm-producing (BFP) UPEC strains isolated from patients with UTI in Iran were divided into three groups of strong, moderate, and weak BFPs after a quantitative microtiter plate assay, and the involvement of curli and cellulose in adhesion of the strains to T24 cell line was confirmed by the construction of csgD and yedQ mutants of two representative UPEC strains. BFP strains were tested for their genetic diversity, phylogenetic groups, and the presence of 15 VAGs. A significant decrease in adhesion of csgD and yedQ mutant strains confirmed the role of biofilm production in adhesion to uroepithelial cells. A high diversity was found among all three groups of strong (Di= 0.998), moderate (Di= 0.998), and weak (Di= 0.988) BFPs with majority of the strains belonging to phylogroups B2 (44.9%) and A (24.3%). Strong BFP strains carried significantly higher level papEF, hlyA, and iutA than other BFP groups. In contrast, the presence of fimH, focG, sfaS, set-1, and cvaC was more pronounced among weak BFP strains. There exists a high genetic diversity among the BFP strains with different VGA profiles. However, the high prevalence of phylogroup A among BFP strains suggests the fitness of commensal E. coli strains to cause UTI in this country.
查看更多>>摘要：Magnetotactic bacteria (MTB) response to the magnetic field can be classified into north-seeking (NS) and south-seeking (SS), which usually depends on their inhabiting site in the North and South Hemisphere, respectively. However, uncommon inverted polarity was observed on both hemispheres. Here, we studied magnetotactic multicellular prokaryotes (MMPs) from a coastal lagoon in Brazil collected in April and August 2014. MMPs from the first sampling period presented both magnetotactic behaviors, while MMPs collected in August/2014 were only SS. Phylogenetic analysis based on the 16S rRNA coding gene showed that these organisms belong to the Deltaproteobacteria class. The 16S rRNA gene sequences varied among MMPs regardless of the sampling period, and similarity values were not related to the type of magnetotactic response presented by the microorganisms. Therefore, differences in the magnetotactic behavior might result from the physiological state of MMPs, the availability of resources, or the instability of the chemical gradient in the environment. This is the first report of NS magnetotactic behavior on MMPs from the South Hemisphere.
查看更多>>摘要：Blakeslea trispora has great potential uses in industrial production because of the excellent capability of producing a large quantity of carotenoids. However, the mechanisms of light-induced carotenoid biosynthesis even the structural and regulatory genes in pathways remain unclear. In this paper, we reported the first transcriptome study in B. trispora in which we have carried out global survey of expression changes of genes participated in blue light response. We verified that the yield of beta-carotene increased 3-fold when transferred from darkness to blue light for 24 h and the enhancement of transcription levels of carRA and carB presented a positive correlation with the increase in carotenoid production. RNA-seq analysis revealed that 1124 genes were upregulated and 740 genes were downregulated respectively after blue light exposure. Annotation through GO, KEGG, Swissprot, and COG databases showed 11119 unigenes compared well with known gene sequences, 5514 unigenes were classified into Gene Ontology, and 4675 unigenes were involved in distinct pathways. Among the blue light-responsive genes, 4 genes (carG1, carG3, carRA and carB) identified to function in carotenoid metabolic pathways were dominantly upregulated. We also discovered that 142 TF genes belonging to 45 different superfamilies showed significant differential expression (p <= 0.05), 62 of which were obviously repressed by blue light. The detailed profile of transcription data will not only allow us to conduct further functional genomics study in B. trispora, but also enhance our understanding of potential metabolic pathway and regulatory network involved in light-regulated carotenoid synthesis.
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Springer Nature