Mohammad Minnatul Karim

A biodegradable polymer film made from waste biomass offers multifunctional properties, driving economic growth and promoting environmental research. In this study, okra fiber‐based biomass was utilized to synthesize 2,3‐dialdehyde cellulose (DAC) through controlled periodate oxidation. Reaction parameters, including the cellulose‐to‐KIO4 ratio (2:1, 1:1, 1:2, 1:3), reaction time (3.0–5.0 h), and temperature (50.0–70.0 °C), were systematically varied. The resulting samples were characterized using FTIR, XRD, SEM, TGA, and titrimetric methods to quantify aldehyde groups. Aldehyde functionalities were confirmed by carbonyl bands observed at 1740–1720 and 800–1030 cm⁻¹ in the FTIR spectra. SEM imaging revealed distinct morphological changes, and the amorphous content increased with higher aldehyde levels. DAC exhibited lower thermal stability compared to fibrillated cellulose. To enhance antibacterial properties, Ag‐sericin (Ag‐SS) nanoparticles were incorporated into DAC. DAC and Ag‐SS/DAC films were fabricated using the solvent casting method. The Ag‐SS/DAC film demonstrated significantly improved tensile strength and modulus. Antimicrobial tests confirmed the composite films effective activity against both Gram‐positive ( Staphylococcus aureus ) and Gram‐negative ( Escherichia coli ) bacteria. The developed film exhibits notable strength and robust antibacterial properties, suggesting its potential use in packaging applications.

Lignin, due to its structural diversity and biodegradability has emerged as a promising alternative to hazardous synthetic materials in multidisciplinary research area. The aim of this paper is to evaluate the lignin potential in value-added applications to be exact zinc oxide nanoparticle synthesis. First, lignin was extracted from coconut husk via sonochemical route in alkaline medium. Afterward, lignin-zinc oxide hybrid nanoparticles (L-ZnO NPs) were synthesized by the reaction of zinc acetate dihydrate salt and lignin, where lignin acts as bioreducing and capping agent. The synthesized lignin and L-ZnO NPs were characterized by UV-Vis spectroscopy, FTIR Spectroscopy, XRD and FESEM analysis. All the identification tests supported the existence of lignin and L-ZnO NPs. The XRD and SEM images disclosed the formation of hexagonal wurtzite shape L-ZnO NPs having mean diameter ≈ 77.76 nm. The antibacterial efficacies of the L-ZnO NPs were assessed against both gram-negative E. coli and gram-positive S. aureus bacteria, employing standard controls and the well diffusion method. The L-ZnO NPs exhibited marvelous bactericidal action against the test microorganisms displaying sufficient zone of inhibition. The photocatalytic performance of the L-ZnO NPs was observed by methylene blue (MB) dye degradation test under UV light irradiation. The UV-Vis absorbance and conductivity tests suggested that the L-ZnO NPs has noticeable photocatalytic efficiency on MB dye degradation. Therefore, the synthesized L-ZnO NPs possess excellent versatile properties and it can be used in medicinal applications and environmental management.

Despite the association of prevalent health conditions with coronavirus disease 2019 (COVID-19) severity, the disease-modifying biomolecules and their pathogenetic mechanisms remain unclear. This study aimed to understand the influences of COVID-19 on different comorbidities and vice versa through network-based gene expression analyses. Using the shared dysregulated genes, we identified key genetic determinants and signaling pathways that may involve in their shared pathogenesis. The COVID-19 showed significant upregulation of 93 genes and downregulation of 15 genes. Interestingly, it shares 28, 17, 6 and 7 genes with diabetes mellitus (DM), lung cancer (LC), myocardial infarction and hypertension, respectively. Importantly, COVID-19 shared three upregulated genes (i.e. MX2, IRF7 and ADAM8) with DM and LC. Conversely, downregulation of two genes (i.e. PPARGC1A and METTL7A) was found in COVID-19 and LC. Besides, most of the shared pathways were related to inflammatory responses. Furthermore, we identified six potential biomarkers and several important regulatory factors, e.g. transcription factors and microRNAs, while notable drug candidates included captopril, rilonacept and canakinumab. Moreover, prognostic analysis suggests concomitant COVID-19 may result in poor outcome of LC patients. This study provides the molecular basis and routes of the COVID-19 progression due to comorbidities. We believe these findings might be useful to further understand the intricate association of these diseases as well as for the therapeutic development.

Quorum sensing (QS) enables virulence factors in bacteria for biofilm formation and pathogenic invasion. Therefore, quorum quenching (QQ), disruption of QS circuit, becomes an alternative antimicrobial therapy. In this study, leaf extract of Gynura procumbens (GP) was used to inhibit biofilm and virulent factors in Pseudomonas aeruginosa. The extract inhibited the biofilm production (p ≤ 0.05) in P. aeruginosa strains MZ2F and MZ4A. The minimum biofilm eradication concentration (MBEC) was recorded at 250 and 500 μg/ml while total activity was found at 288 and 144 ml/g, respectively. Moreover, a significant reduction of virulence factors (p ≤ 0.05) at sub-MBEC without affecting the growth implies the QQ action of the extract. The bioactive fractions were rich in polyphenols and tentatively identified as quercetin and myricetin (R_f=0.53-0.60). Furthermore, we employed computational methods to validate our findings and their interactions with QS receptors (LasR and RhlR). Interestingly, docking studies have also shown that quercetin and myricetin are the promising anti-QS agents out of 31 GP compounds. Notably, their binding affinity ranged between −9.77 and −10.52 kcal/mol for both QS receptors, with controls ranging from −5.40 to −8.97 kcal/mol. Besides, ΔG of quercetin and myricetin with LasR was −71.56 and −74.88 kcal/mol, respectively. Moreover, compounds were suitable drug candidates with stable binding interactions. Therefore, the anti-QS activity of GP leaves and the identified polyphenols can be used in developing QQ-based therapeutics. Communicated by Ramaswamy H. Sarma

In this study, we investigated the effect of long-term pesticides and chemical fertilizers application on the microbial communities specifically anammox and denitrification bacteria in rice field soils. The abundances of microbial communities (16S rDNA), anammox (hszB), and denitrification (narG, nirK, nirS, and nosZ) genes were quantified by q-PCR. 10 pesticides (5 insecticides, 3 fungicides and 2 herbicides) and chemical fertilizers urea, potassium, phosphate, DAP (di-ammonium phosphate), gypsum, and boric acid were used by local farmers. Nitrate, SOC (ammonia, soil organic carbon), N and C content significantly (p < 0.05) decreased in the rice field soils as compared to the upland soils. Abundance of 16S rDNA, hszB, narG, nirK, nirS, and nosZ genes significantly (p < 0.05) decreased in the rice field soils and positively correlated with chemical properties of soils. Our results provide useful information and further maintenance should be instilled to the potential of chemical and biological factors decreased in rice field soils.

With the emergence of multidrug-resistant ‘superbug’, conventional treatments become obsolete. Quorum quenching (QQ), enzyme-dependent alteration of quorum sensing (QS), is now considered as a promising antimicrobial therapy because of its potentiality to impede virulence gene expression without resulting in growth inhibition and antibiotic resistance. In our study, we intended to compare between two major QQ enzyme groups (i.e., AHL lactonases and AHL acylases) in terms of their structural and functional aspects. The amino acid composition-based principal component analysis (PCA) suggested that probably there is no structural and functional overlapping between the two groups of enzymes as well as within the lactonase enzymes but the acylases may functionally be affected by one another. In subcellular localization analysis, we also found that most lactonases are cytoplasmic while acylases are periplasmic. Investigation on the secondary structural features showed random coil dominates over α-helix and β-sheet in all evaluated enzymes. For structural comparison, the tertiary structures of the selected proteins were modelled and submitted to the PMDB database (Accession ID: PM0081007 to PM0081018). Interestingly, sequence alignment revealed the presence of several conserved domains important for functions in both protein groups. In addition, three amino acid residues, namely aspartic acid, histidine, and isoleucine, were common in the active sites of all protein models while most frequent ligands were found to be 3C7, FEO, and PAC. Importantly, binding interactions of predicted ligands were similar to that of native QS signal molecules. Furthermore, hydrogen bonds analysis suggested six proteins are more stable than others. We believe that the knowledge of this comparative study could be useful for further research in the development of QS-based universal antibacterial strategies.

Pseudomonas aeruginosa is an emerging opportunistic pathogen responsible for cystic fibrosis and nosocomial infections. In addition, empirical treatments are become inefficient due to their multiple-antibiotic resistance and extensive colonizing ability. Quorum sensing (QS) plays a vital role in the regulation of virulence factors in P. aeruginosa. Therefore, attenuation of virulence by QS inhibition could be an alternative and effective approach to control the infections. In this study, we sought to discover new QS inhibitors (QSIs) against LasR receptor in P. aeruginosa using chemoinformatics. Initially, a structure-based high-throughput virtual screening was performed using the LasR active site that identified 61404 relevant molecules. The e-pharmacophore (ADAHH) screening of these molecules rendered 72 QSI candidates. In standard-precision docking, only 7 compounds were found as potential QSIs based on their higher binding affinity to LasR receptor (-7.53 to -10.32 kcal/mol compared to -7.43 kcal/mol of native ligand). The ADMET properties of these compounds were suitable to be QSIs. Later, extra-precision docking and binding energy calculation suggested ZINC19765885 and ZINC72387263 as the most promising QSIs. The dynamic simulation of the docked complexes showed stable binding affinity and molecular interactions. The current study suggested that these two compounds could be used in P. aeruginosa QS inhibition to combat bacterial infections.