Biology subjects

Tayyab, M.

Publications and source records attributed to Tayyab, M..

3 recordsLinked to original sources

bioRxiv2025

Genetically induced mouse model for colon-specific epithelial cell tumorigenesis driven by loss of K8 and Apc

Loss of keratin 8 (K8) has been shown to increase susceptibility towards colonocyte hyperproliferation and tumorigenesis. However, most colorectal cancer (CRC) mouse models require carcinogen, develop small intestinal tumors or have long latency period. The aim was to establish a genetic, colon-specific and more human like CRC model driven by loss of K8 and Apc. Colon epithelium specific targeting using the CDX2P-CreERT2 mice was used to generate K8flox/flox; CDX2P-CreERT2 and K8flox/flox; CDX2P-CreERT2; Apcflox/+ mice. Body weight and stool consistency were monitored, and colon was analyzed for tumor burden and histopathology. Keratin expression, inflammation, and proliferation were assessed using immunoblotting and immunofluorescence analysis. This data was compared to K8 expression analysis in patients with CRC using UALCAN database. K8 downregulation in adult K8flox/flox; CDX2P-CreERT2 mice triggers mild diarrhea and leads to loss of K8 and reduced partner keratin levels in a mosaic pattern in the colonic epithelium, while ileal K8 protein levels are unchanged. K8-negative colon areas display increased crypt loss and more MPO+ cells predominantly in the proximal colon. Increased colonocyte proliferation is observed as increased percentage of Ki67+ cells and lower IL-22BP protein levels throughout the colon. These mice with additional monoallelic Apc inactivation show increased colon tumor formation. In colon adenocarcinoma patients, K8 expression is decreased independent of disease type and stage, age or gender. New genetic and colon-specific mouse model with loss of K8 and Apc adequately resembles human CRC. This study also highlights a role of colonocyte K8 in maintaining colon epithelial integrity and protecting against colon tumorigenesis.

cancer biology↗

bioRxiv2024

3D modeling of thermostable xylanase from Thermotoga naphthophila a member of GH10 family: characterization studies of recombinant xylanase

The current study was planned keeping in view the significance, industrial impact and import of xylanase to Pakistan. In this study, a thermostable recombinant xylanase from Thermotoga naphthophila was produced and characterized. The PCR product (1.1 kb) was purified, ligated in the pTZ57R/T and was used for transformation of DH5 cells. The presence of the gene in the recombinant pTZ57R/T was confirmed by restriction analysis. The gene was sub-cloned in pET21a and expression was examined using BL21 CodonPlus (DE3) cells. The recombinant xylanase was expressed as an intracellular soluble protein. SDS-PAGE demonstrated the purified recombinant xylanase as 37 kDa protein. Xylanase showed its optimal activity at 90{degrees}C and pH 7. The enzyme was found thermostable and retained 67% activity after an incubation of 1.5h at 90{degrees}C in the presence of Mn2+. The xylanase activity was enhanced in the presence of Triton X-I00 while the presence of SDS, Tween 20 and Tween 80 showed a declined impact on the activity. Kinetics studies showed the Vmax and Km values of 2313 mol/mg/min and 3.3 mg/ml respectively. The 3D structure analysis demonstrated the presence of a conserved active site comprised of two glutamate and substrate accommodate sites comprised of + 1, +2 and -1, -2 xylose binding sites in the structure of xylanase. The ability of this thermostable xylanase to work at a wide range of temperatures and pH makes it a suitable candidate for industrial applications.

biochemistry↗

bioRxiv2021

Proteomic insight into soybean response to flooding stress reveals changes in basic energy metabolism and cell wall modifications

Soybean is a legume crop enriched with proteins and oil. It is frequently exposed to anthropogenic and natural flooding that limits its growth and yield. Current study applied gel-free proteomic techniques to unravel soybean response mechanism to flooding stress. Two-days-old soybeans were flooded for 4 days continuously and root samples were collected at days 2 to 6 for proteomic and enzymatic analyses. Age-matched untreated soybeans were collected as control. After protein extraction, purification and tryptic digestion, the peptides were analyzed on nano-liquid chromatography-mass spectrometry. A total of 539 and 472 proteins with matched peptides 2 or more were identified in control and flooded seedlings, respectively. Among these 364 proteins were commonly identified in both control and flooded soybeans. Fourty-two proteins abundances were changed 4-fold after 2-days of flooding stress as compared to starting point. The cluster analysis showed that highly increased proteins included cupin family proteins, enolase, pectin methylesterase inhibitor, glyoxalase II, alcohol dehydrogenase and aldolase. The enzyme assay of enolase and pectin methylesterase inhibitor confirmed protein abundance changes. These findings suggest that soybean adopts the less energy consuming strategies and brings biochemical and structural changes in the cell wall to effectively respond to flooding stress and for the survival.

biochemistry↗