Biology subjects

Hassan, M. K.

Publications and source records attributed to Hassan, M. K..

4 recordsLinked to original sources

bioRxiv2021

Screening of plant growth-promoting rhizobacterial strains for the degradation and utilization of exogenous pectin as a sole carbon source

Universal primers for gyrB were used to screen 79 strains of Bacillus species. The genomic DNA from each strain was extracted, and the PCR product of gyrB was amplified and purified for gene sequencing. Gene sequences were edited, and aligned, and Bacillus amyloliquefaciens subsp. plantarum (Bap) strains identified based on the gyrB phylogenetic tree. Two primers (exuT and uxuB) were designed to detect pectin-associated transporter gene exuT and D-mannonate oxidoreductase gene uxuB. The Bap strains were then screened for the presence of the exuT and uxuB genes. These two pectin-utilizing genes were confirmed in 57 and 54 Bap strains by PCR amplification. Second, an in vitro tests were conducted to screen 59 Bap strains using pectin as a sole carbon source to confirm the pectate lyase and utilizing activity. Pectate Agar (PA) and Tris-Spizizen Salts (TSS) medium were used for the in vitro pectate lyase and degradation assays.

microbiology↗

bioRxiv2021

In vitro pectate lyase activity and carbon uptake assays and whole genome sequencing of Bap strains for a pectin defective pathway

The pectin lyase activity of 59 Bacillus amyloliquefaciens subsp. plantarum (Bap) strains was tested in vitro on Pectate Agar (PA) and Tris-Spizizen Salts (TSS) medium. Bap strains were cultured on TSA medium and washed three times with sterile water before the inoculation on PA media. Higher and lower pectate lyase activity were observed in six (AP193, AP203, AP299, AP80, AP102, and AP52) and four (AP 194, AP214, AP215, and AP305) Bap strains compared to other Bap strains. A total of 12 Bap strains (AP67, AP71, AP77, AP78, AP85, AP102, AP108, AP135, AP143, AP189, AP192, and AP193) grew vigorously on TSS medium. A total of six Bap strains (AP194, AP204, AP214, AP216, AP219, and HD73) had lower growth compared to other Bap strains. Pectin (1%) were used for in vitro PA and TSS medium. Pectate lyase and utilization activity were not found in Bacillus thuringiensis subsp. kurstaki strain HD73 compared to Bap strains. A draft genome sequence for strains AP194 and AP214 that were negative for pectin utilization were generated using an Illumina MiSeq. RAST analysis revealed that the pectin-associated gene altronate hydrolase (uxaA) absent in AP 214 strain. Multiple amino acid alignments of exuT and uxuB gene sequence showed dissimilarities among AP194, AP214, and reference Bap strains.

plant biology↗

bioRxiv2020

Phylogenomics of scorpions reveal a co-diversification of scorpion mammalian predators and mammal-specific sodium channel toxins

Scorpions constitute a charismatic lineage of arthropods and comprise more than 2,500 described species. Found throughout various tropical and temperate habitats, these predatory arachnids have a long evolutionary history, with a fossil record that began in the Silurian. While all scorpions are venomous, the asymmetrically diverse family Buthidae harbors nearly half the diversity of extant scorpions, and all but one of the 58 species that are medically significant to humans. Many aspects of scorpion evolutionary history are unclear, such as the relationships of the most toxic genera and their constituent venom peptides. Furthermore, the diversification age of toxins that act specifically on mammalian ion channels have never been inferred. To redress these gaps, we assembled a large-scale phylogenomic dataset of 100 scorpion venom transcriptomes and/or genomes, emphasizing the sampling of highly toxic buthid genera. To infer divergence times of venom gene families, we applied a phylogenomic node dating approach for the species tree in tandem with phylostratigraphic bracketing to estimate minimum ages of mammal-specific toxins. Our analyses establish a robustly supported phylogeny of scorpions, particularly with regard to relationships between medically significant taxa. Analysis of venom gene families shows that mammal-specific sodium channel toxins have independently evolved in five lineages within Buthidae. The temporal windows of mammal-specific toxin origins are contiguous with the basal diversification of major scorpion mammal predators such as carnivores, shrews, bats and rodents. These results suggest an evolutionary arms race model comprised of co-diversification of mammalian predators and NaTx homologs in buthid venom.

evolutionary biology↗

bioRxiv2019

IQGAP2 acts as a tumor suppressor in breast cancer and its reduced expression promotes cancer growth and metastasis by MEK/ERK signalling pathways

IQGAP2 is a member of IQGAPs scaffolding protein family. It has been reported as a tumor suppressor in various cancers, as well as, an oncogene in some cancers, suggesting organ specific role. Need to identify therapeutic targets which function in ER/PR independent way, prompted us to explore role of IQGAP2 in molecular mechanism in breast cancer, which was completely unknown. In vitro studies in estrogen receptor positive breast cancer cell line (MCF7) showed that low IQGAP2 expression results in increased cell proliferation, migration and invasion of cells whereas an opposite effect was observed with ectopic expression of IQGAP2. Triple negative breast cancer cell line (MDA-MB-468), with IQGAP2 depletion showed similar effect, supporting its role in ER/PR independent manner. Furthermore, we found that reduced IQGAP2 expression induces the expression of EMT markers; twist and N-cadherin and decreases the expression of MET marker, E-cadherin via the MEK/ERK pathway but not via AKT pathway. Validation of findings in patients showed a reduced IQGAP2 expression in breast cancer tissues compared to normal tissue. Patients with low levels of IQGAP2 showed correlation with higher tumor stage. Our results suggest that IQGAP2 acts as a tumor suppressor and its down regulation results in cell growth, cell invasion and EMT through the MEK/ERK signalling pathways and it hence may be a potential therapeutic target in breast cancer.

cancer biology↗