Biology subjects

Ashraf, M. A.

Publications and source records attributed to Ashraf, M. A..

9 recordsLinked to original sources

bioRxiv2025

Myosin II independent contraction of actin filaments in membrane nanotubes

The ability to generate active stresses within filamentous actin matrices is a fundamental and evolutionarily conserved process driving locomotion and morphogenetic changes in cells. The generation of pushing forces by actin polymerization is reasonably well understood, and is known to drive lamellipodia based motility and filopodial extension. Actin filaments decorated with myosin motors can also generate contractile stresses as in the cell cortex or in cytokinetic rings. In this article we use membrane nanotubes pulled out of axonal shaft to investigate actin dynamics and force generation. We report cyclic growth and retraction dynamics of actin within the tube and correlated contraction events giving rise to sustained load and fail cycles. The contraction mechanism operate independent of myosin II motor proteins. Furthermore, we analyzed the dynamics of actin within the tube, including under various biochemical or genetic perturbations. By combining these results with physical modeling, we argue that stresses generated in the actin filaments by the binding of actin depolymerizing factor (ADF/cofilin) proteins can explain the cyclic load-fail behavior.

biophysics↗

bioRxiv2025

Lead, a toxic metal, alters auxin-mediated root growth and gravitropic responses in maize and Arabidopsis

Toxic metal contamination in the environment is pervasive and of significant concern due to its high abundance in agricultural lands across the globe. Future engineering of plants tolerant to toxic metals requires a detailed understanding of plant responses to these toxins, which are currently poorly understood. We discovered that, among four toxic metals, lead (Pb) targets conserved cellular and developmental processes in evolutionary diverse plant systems - the model plant Arabidopsis thaliana and crop plant Zea mays. This study shows that Pb increases the phytohormone auxin, which in turn inhibits cell cycle progression to inhibit root growth and alters root gravitropic responses. Both root growth and gravitropic responses are critical for soil exploration, which is required for plants to live and thrive in harsh environments.

plant biology↗

bioRxiv2023

Substrate specificity and functional conservation of SWEET10 transporter in pineapple

O_LISWEET transporters are a unique class of sugar transporters that play vital roles in various developmental and physiological processes in plants. C_LIO_LIWhile the functions of SWEETs have been well established in model plants such as Arabidopsis, their functions in economically important fruit crops like pineapple have not been well studied. C_LIO_LIThis study investigated the substrate specificity of pineapple SWEETs by comparing the protein sequences of known glucose and sucrose transporters in Arabidopsis to those in pineapple. C_LIO_LIGenome-wide approach and 3D structure comparison showed that the Arabidopsis SWEET8 homolog in pineapple, AcSWEET10, shares similar sequences and protein properties responsible for glucose transport. To determine the functional conservation of AcSWEET10, its ability to complement glucose transport mutants in yeast, its expression in stamens, and its impact on the microspore phenotype and seed set in transgenic Arabidopsis were analyzed. C_LIO_LIAcSWEET10 was found to be functionally equivalent to AtSWEET8 and plays a critical role in regulating microspore formation through the regulation of CalS5. C_LIO_LIManipulating SWEET transporter activity could have important implications for improving fruit crop yield and quality. C_LI

plant biology↗

bioRxiv2022

An outer nuclear membrane protein promotes a polarized nuclear position and the future division plane during asymmetric cell division

Asymmetric cell division generates new cell types and is a feature of development in multicellular organisms. Prior to asymmetric cell division, cell polarity is established. Zea mays stomatal development serves as an excellent plant model system for asymmetric cell division, especially the asymmetric division of the subsidiary mother cell (SMC). In SMCs, the nucleus migrates to a polar location after the accumulation of polarly localized proteins, but before the appearance of the preprophase band. We examined a mutant of the outer nuclear membrane protein, which is part of the LINC (linker of nucleoskeleton and cytoskeleton) complex that localizes to the nuclear envelope in interphase cells. Previously, mlks2 (maize linc kash sine-like2) was observed to have abnormal stomata. We confirmed and identified the precise defects that lead to abnormal asymmetric divisions. Proteins that are polarly localized in SMCs prior to division polarize normally in mlks2. However, polar localization of the nucleus is sometimes impaired, even in cells that have otherwise normal polarity. This leads to a misplaced preprophase band and atypical division planes. MLKS2 is localized to mitotic structures, however the structure of the preprophase band, spindle and phragmoplast appeared normal in mlks2. Timelapse imaging revealed that mlks2 has defects in pre-mitotic nuclear migration towards the polarized site, and unstable position at the division site after formation of the preprophase band. We show that nuclear envelope proteins promote pre-mitotic nuclear migration and stable nuclear position, and that the position of the nucleus influences division plane establishment in asymmetrically dividing cells. One-sentence summaryNuclear movement and positioning prior to asymmetric cell division is required for deciding the future division site.

plant biology↗

bioRxiv2020

An assessment of efficacy of Iodine complex (Renessans) against SARS-CoV-2 in non-human primates (Rhesus macaque)

Renessans is an iodine complex which has proven in vitro antiviral activity including Anti-SARS-CoV-2 activity. The present study was designed to determine its efficacy against SARS-CoV-2 in monkeys (Rhesus macaque). A total of 14 monkeys were divided into four groups: A) Prophylactic group (n=03), (B) Treatment group (n=03), (C) infection control group (n=04) and (D) negative control group (n=04) and were housed in BSL-3 Animal facility while group D was housed at another animal house. Group A was administered with Renessans @ 2.85 mg/7 kg from 5 days prior to the infection to 08 days post infections (DPI). Group B was administered with Renessans from 03-08 DPI @ 2.85 mg/7 kg. Group C was administered with WIF only. The infection @ 2 x 106 TCID of SARS-CoV-2 was given to all group monkeys through intranasal and oral route under anesthesia. Nasal swab samples (at different times) and fecal matter on daily basis were collected for the detection of SARS-CoV-2 through real-time quantitative PCR. Three monkeys (one from each of group A, B and C) were euthanized at 07 DPI to determine the gross pathological lesions and SARS-CoV-2 detection from internal tissues. Nasal swabs from all the monkeys from group A, B and C were positive for SARS-CoV-2 at 02 and 07 DPI (Day 05 of treatment). At 14 DPI, all (100%) nasal swabs from group A were negative for SARS-CoV-2 while 50% and 100% were positive from group B and C, respectively. At 21 DPI, monkeys from group B were negative and all in group C were still positive for SARS-CoV-2. Similarly, fecal matter of monkeys in group A and B was returned negative in significantly lesser time as compared to monkeys from infection control group. Based on these research findings it is concluded that the Renessans has in-vivo SARS-CoV-2 activity and may result in early clearance of SARS-CoV-2. Therefore, a clinical trial of the drug in COVID-19 patients may reveal its anti-COVID-19 potential.

microbiology↗

bioRxiv2020

An Algorithmic framework for genome-wide identification of Sugarcane (Saccharum officinarum)-encoded microRNA Targets against SCBV

Sugarcane Bacilliform Virus (SCBV) is considered an economically the most damaging pathogen for sugarcane production worldwide. Three ORFs are characterized in a single molecule of circular, ds-DNA genome of the SCBV, encoding for hypothetical protein (ORF1), DNA binding protein (ORF2) and Polyprotein (ORF3). The study was aimed to predict and comprehensively evaluate sugarcane miRNAs for the silencing of SCBV genome using in-silico algorithms. Computational methods were used for prediction of candidate miRNAs from sugarcane (S. officinarum L.) to silence the expression of SCBV genes through translational inhibition by mRNA cleavage. Mature sugarcane miRNAs were retrieved and were assessed to hybridization with the SCBV genome. A total of fourteen potential candidate miRNAs from sugarcane were computed by all the algorithms used for the silencing of SCBV. A consensus of three algorithms predicts hybridization sites of sof-miR159e at common locus 5534. The miRNA-mRNA interaction was estimated by computing free-energy of miRNA-mRNA duplex using RNAcofold algorithm. Regulatory network of predicted candidate miRNAs of sugarcane with SCBV ORFs, generated using Circos, identify novel targets. Consequently, detecting and discarding inefficient amiRNAs prior to cloning would help suppressed mutants faster. The efficacy of predicted candidate miRNAs was evaluated to test the survival rate of the in vitro amiRNA-mediated effective badnaviral silencing and resistance in sugarcane cultivars.

bioinformatics↗

bioRxiv2020

Honeyweed (Leonurus sibiricus) and Buckwheat (Fagopyrum esculentum) supplemented diet improve growth performance, lipid profile and hematological values of broiler chicks

The study was conducted to investigate the combined effects of honeyweed (HW) and buckwheat (BW) supplemented diets on the growth, feed intake, serum lipid profile and blood parameters in broiler chicks. One hundred fifty (150) day old chicks (Cobb-500) were divided into five groups viz. T1 (Commercial control, CC), T2 (FF+10% BW), T3 (FF+10% BW +5% (w/v) HW powder), T4 (FF+10% BW +10% (w/v) HW powder), T5 (FF+10% BW +15% (w/v) HW powder) in complete randomized design with five (5) replications, each of which contain six (6) birds. The CC feed and the FF with HW and BW supplemented diet fed on broiler for 30 days. At the end of the study, the body weight gain, FCR and mortality rate were calculated. It was found that T3 (FF+10% BW +5% (w/v) HW powder) diet significantly (p <0.05) showed the good FCR, mortality rate and body weight gain. Interestingly, T3 decreased the serum cholesterol, triglycerides (TG), low density lipoprotein (LDL), increased high density lipoprotein (HDL) and improves blood parameters significantly (p < 0.05). Our results suggested that this newly formulated feed T3 (FF+10% BW +5% (w/v) HW powder) could be considered as an alternative natural feed additive to hazardous synthetic antibiotics.Competing Interest StatementThe authors have declared no competing interest.View Full Text

animal behavior and cognition↗

bioRxiv2019

CDK4 as a phytochemical based anticancer drug target

Success story of plant-based medicine had been overlooked during the advent of modern pharmaceutical industry. Despite the negligence of the multimillion-dollar drug industry, people entirely rely on medicinal plants in some part of the world. In this study, we have emphasized on going back to those traditional medicinal practices to figure out their underlying mechanism to move forward on phytochemical based drug development. We screened Medicinal Plant Database Bangladesh 1.0 (MPDB1.0) and on-going extension, MPDB2.0, of that database to find traditionally used medicinal plants and their active compounds. Here, Mangiferin, extracted from Mangifera indica, have been demonstrated to interact with cell cycle regulator Cyclin-dependent Kinase 4 (CDK4). CDK4 is differentially expressed during Glioblastoma multiforme (GBM), Brain Lower Grade Glioma (LGG), and Sarcoma (SARC). Expression of CDK4 is interlinked to the patients survival rate and its consistent expression throughout different stages have provided the advantage to use it as diagnostic tool and drug target. Altogether, this study demonstrated that simple mango tree extracted active compounds, mangiferin, can work as potential anticancer drug and leveraging the recent advancement of sequencing and gene expression data can accelerate the phytochemical based drug discovery process.

cancer biology↗

bioRxiv2019

ATP Binding Cassette Proteins ABCG37 and ABCG33 are required for potassium-independent cesium uptake in Arabidopsis roots

Radiocesium, accumulated in the soil by nuclear accidents is a major environmental concern. The transport process of cesium (Cs+) is tightly linked to the indispensable plant nutrient potassium (K+) as they both belong to the group I alkali metal with similar chemical properties. Most of the transporters that had been characterized to date as Cs+ transporters are directly or indirectly linked to K+. Using a combinatorial approach of physiology, genetics, cell biology and root uptake assay, here we identified two ATP-Binding Cassette (ABC) proteins, ABCG37 and ABCG33 as facilitators of Cs+ influx. The gain-of-function mutant of ABCG37 (abcg37-1) showed hypersensitive response to Cs+-induced root growth inhibition, while the double knock out mutant of ABCG33 and ABCG37 (abcg33-1abcg37-2) showed resistance. Single loss-of-function mutant of ABCG33 and ABCG37 did not show any alteration in Cs+ response. Short term uptake experiment with radioactive Cs+ revealed reduced Cs+ uptake in abcg33-1abgc37-2 compared with wild type in presence or absence of K+. Potassium response and content were unaffected in the double mutant background confirming that Cs+ uptake by ABCG33 and ABCG37 is independent of K+. Collectively, this work identified two ABC proteins as new Cs+ influx carriers, which act redundantly and independent of K+ uptake pathway.

plant biology↗