Biology subjects

Ejaz, S.

Publications and source records attributed to Ejaz, S..

4 recordsLinked to original sources

bioRxiv2025

Phenotypic and Molecular characterization of thermophlic bacterial isolates from the rizosphere of Panicum antidotale in Cholistan desert, Pakistan

The major aim of this study was to isolate, characterize, and determine the distribution of culturable bacteria in the rhizosphere of Panicum antidotale (PAMA) from the Cholistan desert, Pakistan. A total of 109 thermophilic bacterial isolates were obtained from PAMA and subjected to morphological, biochemical, and molecular characterization at The Islamia University of Bahawalpur. Standard protocols were used for physical and biochemical analysis, while molecular identification involved 16S rRNA profiling, restriction fragment length polymorphism (RFLP), and DNA sequence analysis. PCR amplicons of selected isolates with distinct RFLP patterns were sequenced, and the DNA sequences were analyzed using BLAST to determine species identity. Results revealed the presence of Bacillus subtilis, Brevibacillus borstelensis, and Paenibacillus dendritiformis in the majority of analyzed rhizosphere samples. Bacillus licheniformis and Bacillus subtilis were the most dominant species in PAMA, accounting for 45% and 30% of the isolates, respectively. In addition, lower frequencies of other species, such as Paenibacillus dendritiformis (10-15%), were also observed. These findings demonstrate that Panicum antidotale supports a unique rhizospheric bacterial community dominated by thermophilic Bacillus species. This study represents the first comprehensive investigation of PAMA microbiota in the Cholistan desert. The results provide novel insights into bacterial diversity in extreme environments and highlight the potential role of these communities in plant growth promotion and stress adaptation. Further studies are warranted to explore the ecological significance and possible biotechnological applications of PAMA-associated thermophilic bacteria for sustainable agriculture and environmental management. ImportanceThis study presents the first molecular-level investigation of thermophilic bacterial communities inhabiting the rhizosphere of Panicum antidotale in the Cholistan Desert, Pakistan. Through combined phenotypic, biochemical, and molecular analyses, diverse thermophilic Bacillus, Brevibacillus, and Paenibacillus species were identified as dominant members of this extreme arid ecosystem. These bacteria possess plant growth-promoting and stress-alleviating traits, underscoring their ecological significance in supporting desert plant resilience. Importantly, this first molecular characterization of P. antidotale-associated microbiota reveals that these isolates may also serve as promising sources of valuable enzymes and bioactive metabolites. The findings broaden our understanding of microbial diversity in arid rhizospheres and highlight the potential applications of these thermophilic bacteria in sustainable agriculture, biotechnology, and environmental management.

microbiology↗

bioRxiv2025

Homeostatic Activation of 26S Proteasomes by Protein Kinase A Protects against Cardiac and Neurobehavior Malfunction in Alzheimer's Disease Mice

Alzheimers Disease (AD) patients often show brain and cardiac malfunction. AD represents a leading cause of morbidity and mortality worldwide, but the demand for effective treatment for AD is far from being met. This is primarily because AD pathogenesis, including brain-heart interaction, is poorly understood. Proteasome functional insufficiency is implicated in AD; as such, proteasome enhancement promises a potentially new strategy to treat AD. The proteasome can be activated by protein kinase A (PKA) via selectively phosphorylating Ser14-RPN6/PSMD11 (p-S14-RPN6); however, whether p-S14-RPN6 is altered and what role p-S14-RPN6 plays in AD remain unclear. Hence, this study was conducted to address these critical gaps. We found that genetic blockade of the homeostatic p-S14-Rpn6 via germline knock-in of Rpn6S14A (referred to as S14A) significantly reduced proteasome activities in the cerebral cortex but did not discernibly impair learning and memory function in 4-month-old mice or cause cardiac dysfunction before 12 months of age. Increases in Ser14-phosphorylated Rpn6 in the cerebral cortex and markedly elevated A{beta} proteins in the myocardium were observed in young 5XFAD mice, a commonly used AD model. When introduced into the 5XFAD mice, S14A significantly aggravated the learning and memory deficits as revealed by the radial arm water maze tests and accelerated cardiac malfunction as measured by serial echocardiography in the same cohort of 5XFAD mice. Thus, the present study establishes for the first time that homeostatic activation of 26S proteasomes by basal p-S14-RPN6 or PKA activity protects against both the brain and heart malfunction in the 5XFAD mice.

physiology↗

bioRxiv2025

Ser14-phosphorylated Rpn6 Limits Proteostasis Impairment and Pathology in Both Brain and Heart of Tauopathy Mice

Alzheimers disease (AD) patients often display neurobehavioral and cardiac impairments, but the underlying factors remain unclear. Ser14 phosphorylation in RPN6 (p-S14-RPN6) mediates the activation of 26S proteasomes by protein kinase A (PKA). Proteasome priming is implicated in protection by cAMP-PKA against AD, but this remains to be established. Hence, this study was conducted to interrogate homeostatic p-S14-RPN6 in AD. The recently validated Rpn6S14A knock-in (S14A) mice were crossbred with the PS19 tauopathy mice (RRID: IMSR_JAX:008169). The resultant wild type (WT), PS19, and PS19::S14A littermates were compared. Expedited declines in cognitive and motor functions as indicated respectively by significant decreases in object recognition and discrimination indexes and rotarod time were observed in PS19::S14A mice vs. PS19 mice, which is associated with more pronounced synaptic losses, microglial activation, and gliosis in the hippocampus. Compared with WT and PS19 mice, PS19::S14A mice showed exacerbated cardiac malfunction, cardiac hypertrophic responses and fibrosis, and greater increases of total and hyperphosphorylated tau proteins and ubiquitin conjugates in both hippocampi and hearts. These findings demonstrate that genetic blockade of p-S14-RPN6 exacerbates tauopathy in both the brain and heart, which for the first time establishes that homeostatic p-S14-RPN6 promotes proteostasis and protects against pathogenesis in AD.

cell biology↗

bioRxiv2018

Biochemical, molecular and antibiotic resistance profile of multi-potential toluene metabolizing bacteria isolated from tannery effluents

The focus of present study was to isolate and characterize bacteria which can be effectively used for toluene, a highly recalcitrant pollutant, bioremediation. For isolation of bacteria from the tannery effluents selective enrichment and serial dilution methods were employed. The isolated bacteria were subjected to growth curve analysis, estimation of toluene removal efficiencies, biochemical tests, antibiotic sensitivity assays and molecular characterization based upon 16S rRNA gene. The rRNA genes sequences were analyzed through BLAST to determine similarity index of isolates with bacterial database sequences. To trace the evolutionary history, phylogenetic trees were constructed using MEGA version 7. Total twenty toluene metabolizing bacteria (IUBT1-2, 4-12, 16, 19, 21, 23-26, 28 and 30) were isolated and characterized. Their rRNA gene sequences have been submitted to Genbank. Fifteen of the twenty isolates showed homology to Brevibacillus agri strain NBRC 15538, four found similar to Bacillus paralicheniformis strain KJ-16 and one homologous to Burkholderia lata strain 383. All bacterial isolates were resistant to chloramphenicol but sensitive to teicoplanin and linezolid. However, few (i. e.; IUBT9 and 26) were sensitive to oxacillin. Biochemical characterization indicated all bacteria positive for alkaline phosphatases (100%). While many were found positive for p-nitrophenyl N-acetyl {beta}, D-glucosaminidase (35%), hydroxyproline {beta}-naphthylaminopeptidase (15%), esculinase (65%), mannitol (75%), sorbitol (95%) and inulin (90%) fermentation. Biochemical profile suggests the use of isolated bacteria for future exploitation in several fields like bioremediation of toluene, ethanol production, biomass hydrolysis, biosensors, biofertilizers, as a marker for milk pasteurization in dairy industries and evaluation of soil quality.\n\nImportanceToluene is a highly toxic environmental pollutant. We have isolated bacteria which can be effectively used for the removal of toluene from environmental resources. Moreover, these bacteria are capable to produce many valuable enzymes which can be used in many industrial processes for the production of a wide range of products. Further study may help to exploit these bacterial for the benefit of humanity.

microbiology↗