The Neuroprotective Propensity of Organic Extracts of Acacia stenophylla Bark and Their Effectiveness Against Scopolamine-/Diazepam-Induced Amnesia in Mice.

Background: Alzheimer's disease (AD) is a neurodegenerative disorder that is more prevalent in the elderly. There is extensive literature on using Acacia species against central nervous system disorders, although Acacia stenophylla has not been investigated for any neuroprotective potential. The purpose of the study was to elucidate the ameliorative effect of ethyl acetate (ASEE) and butanol (ASB) extracts from the bark of A. stenophylla on memory deficits and cognitive dysfunction in scopolamine- or diazepam-induced amnesia in mice. Methods: The phytochemical constituents of the extracts of A. stenophylla were determined by GC-MS and the in vitro anticholinesterase plus antioxidant activities were also evaluated. Anti-amnesic effects were determined employing the open field test, elevated plus maze (EPM), Morris water maze (MWM), and Y-maze paradigms. Results: The in vitro cholinesterase assays disclosed a concentration-dependent inhibition of both AChE and BuChE with IC50 values of 28.48 and 44.86 µg/mL for the ASEE extract and 32.04 and 50.26 µg/mL for the ASB extract against AChE and BuChE respectively. DPPH and H2O2 antioxidant assays revealed respective IC50 values for the ASEE extract of 28.04 and 59.84 µg/mL, plus 32.77 and 64.65 µg/mL for ASB extract. The findings revealed that both extracts possessed substantial antioxidant properties. Furthermore, these fractions restored scopolamine- and diazepam-induced memory deficits in a dose-dependent manner, as observed by a significant decrease in the transfer latency in EPM, reduction in escape latency, added time spent in the target quadrant in the MWM, and elevated spontaneous alternation behavior (SAB) in the Y-maze test. Conclusion: The ameliorative effect of A. stenophylla on scopolamine- and diazepam-induced amnesia can be attributed to antioxidant and anticholinesterase activity. Consequently, the use of A. stenophylla might be exploited in the alleviation of oxidative stress and the management of AD.

Biosynthesis Pathways, Transport Mechanisms and Biotechnological Applications of Fungal Siderophores.

Iron (Fe) is the fourth most abundant element on earth and represents an essential nutrient for life. As a fundamental mineral element for cell growth and development, iron is available for uptake as ferric ions, which are usually oxidized into complex oxyhydroxide polymers, insoluble under aerobic conditions. In these conditions, the bioavailability of iron is dramatically reduced. As a result, microorganisms face problems of iron acquisition, especially under low concentrations of this element. However, some microbes have evolved mechanisms for obtaining ferric irons from the extracellular medium or environment by forming small molecules often regarded as siderophores. Siderophores are high affinity iron-binding molecules produced by a repertoire of proteins found in the cytoplasm of cyanobacteria, bacteria, fungi, and plants. Common groups of siderophores include hydroxamates, catecholates, carboxylates, and hydroximates. The hydroxamate siderophores are commonly synthesized by fungi. L-ornithine is a biosynthetic precursor of siderophores, which is synthesized from multimodular large enzyme complexes through non-ribosomal peptide synthetases (NRPSs), while siderophore-Fe chelators cell wall mannoproteins (FIT1, FIT2, and FIT3) help the retention of siderophores. S. cerevisiae, for example, can express these proteins in two genetically separate systems (reductive and nonreductive) in the plasma membrane. These proteins can convert Fe (III) into Fe (II) by a ferrous-specific metalloreductase enzyme complex and flavin reductases (FREs). However, regulation of the siderophore through Fur Box protein on the DNA promoter region and its activation or repression depend primarily on the Fe availability in the external medium. Siderophores are essential due to their wide range of applications in biotechnology, medicine, bioremediation of heavy metal polluted environments, biocontrol of plant pathogens, and plant growth enhancement.

Molecular and Biochemical Characterization, Antimicrobial Activity, Stress Tolerance, and Plant Growth-Promoting Effect of Endophytic Bacteria Isolated from Wheat Varieties.

Endophytic bacteria have been utilized as an alternative source to chemical fertilizers and pesticides to enhance plant productivity and defense mechanisms against biotic and abiotic stress. Five endophytic bacterial strains were isolated from the seeds of three different Pakistani wheat varieties (Ghaneemat-e-IBGE, Atta-Habib, and Siren). The isolated strains AH-1, S-5, S-7, GI-1, and GI-6 showed phylogenetic similarity with Bacillus altitudinis, B. aryabhattai, B. wiedmannii, Pseudomonas aeruginosa, and Burkholderia gladioli, respectively. All strains showed catalase activity (except AH-1) and Indole-3-acetic acid production, with the highest concentration (16.77 µg·mL-1) found for GI-6, followed by S-5 (11.5 µg·mL-1), nitrogen assimilation (except S-7), phosphorus solubilization (except S-7 and AH-1), and ability to produce siderophores, with maximum productions for GI-6 (31 ± 3.5 psu) and GI-1 (30 ± 2.9 psu). All five analyzed strains possessed antimicrobial activity, which was particularly strong in GI-6 and S-5 against Klebsiella pneumonia, Escherichia coli, and Bacillus subtilis. Increasing salinity stress with NaCl negatively affected the bacterial growth of all isolates. However, strains GI-6 and S-5 showed salt tolerance after three days of incubation. A drought tolerance test resulted in a negative impact of poly ethylene glycol on bacterial growth, which was, however, less pronounced in GI-6 strain. The GI-6 strain revealed growth-promoting effects on inoculated wheat plants.

Dissemination of NDM-1 in pseudomonas aeruginosa and klebsiella pneumoniae isolated from pus samples in tertiary care hospitals of Quetta, Pakistan.

OBJECTIVE: To highlight the prevalence and epidemiology of New Delhi metallo-ß-lactamase-1. producers in pus samples. METHODS: The cross-sectional study was conducted from April to August 2018 at the Biotechnology Laboratory, Balochistan University of Information Technology Engineering and Management Sciences, Quetta, Hi-tech Laboratory, Centre for Advance Studies in Vaccinology and Biotechnology, University of Balochistan, Quetta and Microbiology Laboratory, Bolan Medical Complex Hospital, Quetta, Pakistan. Biochemical and molecular approaches were used for the identification of the isolates and Modified Hodge Test for the phenotypic detection of class-A carbapenemase activity. Minimum Inhibitory Concentration was performed using E-test and broth microdilution method. Molecular basis of carbapenemase activity was ascertained by the recognition of blaNDM-1 gene in the isolates. RESULTS: Of the 300 pus samples taken from surgical/burn units, 6(2%) blaNDM-1 harbouring isolates were found; 3(50%) each being Klebsiella pneumoniae and Pseudomonas aeruginosa. Klebsiella. pneumoniae isolates were extensively drug-resistant. The Pseudomonas aeruginosa isolates displayed resistance against 21 antibiotics of tetracyclines, quinolones, b-lactams, aminoglycosides, monobactams, sulphonamides, macrolides, cephalosporins, phosphonic acid and polypeptide groups, suggesting pan-drug resistance. CONCLUSIONS: The resistance pattern of the bacterial isolates poses a significant clinical threat in the region.

Prevalence of extensive drug resistance in bacterial isolates harboring blaNDM-1 in Quetta Pakistan.

OBJECTIVE: Extensive drug resistant Gram-negative bacilli, harboring New Delhi metallo-ß-lactamase-1 (bla NDM-1) having the ability to hydrolyze ß-lactams, have become a vital global clinical threat. The present study was, therefore, designed to investigate the prevalence and epidemiology of NDM-1 producers in Quetta, Pakistan. METHODS: This study was carried out in Microbiology Laboratory, Bolan Medical Complex Hospital Quetta, Biotechnology laboratory, BUITEMS Quetta and Hi-tech laboratory, CASVAB, University of Balochistan, Quetta, from March to June 2018, during the hot season. Biochemical and molecular approaches were applied for the identification of bacterial isolates. Minimum Inhibitory Concentrations (MICs) were determined using E-test method. Carbapenemase activity was ascertained by Modified Hodge Test (MHT) and the presence of blaNDM-1 gene was recognized by Polymerase Chain Reaction (PCR). RESULTS: We isolated five bla NDM-1 harboring isolates of three different species namely Morganella morganii (n=2) Enterobacter cloacae (n=2) and Citrobacter freundii (n=1), from 300 pus samples. These isolates were found extensive drug resistant (XDR). Strikingly, two isolates of M. morganii were displaying resistance against 23 antibiotics of sulphonamides, aminoglycosides, polypeptide, monobactams, tetracyclines, quinolones, macrolides, cephalosporins, phosphonic acid and ß-lactams groups, suggesting Pan Drug Resistance (PDR). CONCLUSION: This is the first report on emergence of PDR strain of M. morganii producing NDM-1 in the province of Balochistan, Pakistan. The presence of bla NDM-1 in different bacterial species and their extensive rather pan drug resistance pattern poses a momentous clinical threat.