Islam, M. S. — Page 4 | Search bioRxiv

bioRxiv2019

First report of reference guided genome assembly of Black Bengal goat (Capra hircus)

ObjectivesBlack Bengal goat (Capra hircus), a member of the Bovidae family with the unique traits of high prolificacy, skin quality and low demand for food is the most socioeconomically significant goat breed in Bangladesh. Furthermore, the aptitude of adaptation and disease resistance capacity of it is highly notable which makes its whole genome information an area of research interest.\n\nData descriptionThe genomic DNA of local (Chittagong, Bangladesh) healthy Black Bengal goat (Capra hircus) was extracted and then sequenced. The de novo assembly and structural annotations are being presented here. Sequencing was done using Illumina sequencing platform and the draft genome assembled is about 3.04 Gb. 26458 Genes were annotated using Maker gene annotations tool which predicted BUSCO Gene models. Universal Single Copy Orthologs refer 82.5% completeness of the assembled genome.

genomics↗

bioRxiv2018

Deciphering the molecular pathways of apoptosis using leaf extract of Basella alba against Ehrlichs Ascites Carcinoma (EAC) cell line in Swiss albino mice model

A series of programmed cell death that plays a vital role in the exclusion of abnormal cells without any ruin into the surrounding neighboring cells is called Apoptosis. Generally, it occurs in multi-cellular organisms through an orderly and autonomously processes that is controlled by proper function of various genes. In the current studies, cell apoptosis in EAC cells treated with different fractions (BLP-01, BLP-02 and BLP-03) of leaf extract of B. alba was detected by conducting several bio-assays such as cell growth inhibition, fluorescence and optical microscopy, DNA fragmentation and PCR amplification etc. The results of these experiments indicate that the plant extracts are able to inhibit cell growth significantly where mor- phological features of apoptosis were appeared under both fluorescence and optical microscope. The PCR amplification results showed that the leaf extracts of B. alba were able to cause EAC cell apoptosis in both the extrinsic and intrinsic pathway. An excellent figure of fragmented DNA was found in DNA fragmentation assay when the gel was observed under UV light which confirms the cell apoptosis. The current findings suggest that the samples of this experiment occupy fascinating competence to conduct cell apoptosis and become an ideal resource for cancer research as well as drugs development for cancer treatment.

molecular biology↗

bioRxiv2018

Novel cholera toxin variant and ToxT regulon in environmental Vibrio mimicus strains: potential resources for the evolution of Vibrio cholerae hybrid strains

Atypical El Tor strains of Vibrio cholerae O1 harboring variant ctxB genes of cholera toxin (CT) are gradually becoming a major cause of recent cholera epidemics. Vibrio mimicus occasionally contains virulence factors associated with cholera, e.g., CT, encoded by ctxAB on CTX[FE] genome; and TCP, the CTX[FE]-specific receptor. This study carried out extensive molecular characterization of CTX[FE] and ToxT regulon in ctx+ve strains of V. mimicus isolated from the Bengal coast. Southern hybridization, PCR, and DNA sequencing of virulence related-genes revealed the presence of an El Tor type CTX prophage (CTXET) carrying a novel ctxAB, tandem copies of environmental type pre-CTX prophage (pre-CTXEnv), and RS1 elements, which were organized in an array of RS1-CTXET-RS1-pre-CTXEnv-pre-CTXEnv. Additionally, a novel variant of tcpA and toxT respectively, showing clonal lineage to a phylogenetic clade of V. cholerae non-O1/O139, was identified. The V. mimicus strains lacked the RTX and TLC elements, and Vibrio seventh pandemic islands of the El Tor strains, but contained five heptamer (TTTTGAT) repeats in ctxAB promoter region like some classical strains of V. cholerae O1. PFGE analysis showed all the ctx+ve V. mimicus strains were clonally related. However, their in vitro CT production and in vivo toxigenecity were variable, which could be explained by differential transcription of virulence genes along with ToxR regulon. Taken together, our findings strongly suggest that environmental V. mimicus strains act as potential reservoir of atypical virulence factors, including variant CT and ToxT regulon, and may contribute to the evolution of V. cholerae hybrid strains.\n\nIMPORTANCENatural diversification of CTX[FE] and ctxAB genes certainly influences disease severity and shifting patterns in major etiological agents of cholera, e.g., the overwhelming emergence of hybrid El Tor variants, replacing the prototype El Tor strains of V. cholerae. This study showing the occurrence of CTXET comprising a novel variant of ctxAB in V. mimicus points out a previously unnoticed evolutionary event, independent to that of the El Tor strains of V. cholerae. Identification and cluster analysis of the newly-discovered alleles of tcpA and toxT indicates their horizontal transfer from an uncommon clone of V. cholerae. The genomic content of ToxT regulon, and tandemly arranged multiple pre-CTX[FE]Env and a CTX[FE]ET in V. mimicus probably act as salient raw materials inducing natural recombination among the hallmark virulence genes of hybrid V. cholerae strains. This study will facilitate deeper understanding of the evolution of new variant CT and ToxT regulon, influencing cholera epidemiology.

microbiology↗