Molecular Characterization of Monochloroacetate-Degrading Arthrobacter sp. Strain D2 Isolated from Universiti Teknologi Malaysia Agricultural Area

Arthrobacter sp. strains D2 and D3 and Labrys sp. strain D1 capable of degrading 20 mM monochloroacetic acid (MCA) were isolated from soil contaminated with herbicides and pesticides. All three isolates were able to grow on MCA as the sole source of carbon and energy with concomitant chloride ion release in the growth medium (19 mM). Strains D2 and D3 (cells doubling time 7 ± 0.3 h) grew four times faster than D1 (26 ± 0.1 h). Strain D2 was then further investigated and could also grow in 10 mM of monobromoacetic acid (MBA), 2,2-dichloropropionic acid (2,2DCP), d,l-2-chloropropionic acid (D,L2CP), l-2-chloropropionic acid (L-2CP), d-2-chloropropionic acid (D-2CP), and glycolate as the sole sources of carbon and energy. Dehalogenase gene amplification using group I primers revealed a 410-bp polymerase chain reaction (PCR) product, but there was none using group II primers. The partial amino acid sequence analysis of group I DehD2 dehalogenase showed at least 32% identity to the corresponding regions of DehE, DhlIV, DehI, and D,L-DEX, with key amino acid residues Ser188, Ala187, and Asp189. These amino acid residues were involved in substrate binding and catalysis and were conserved in the partial amino acid sequence.     

Computationally Design of Inhibitory Peptides Against Wnt Signaling Pathway: In Silico Insight on Complex of DKK1 and LRP6

Wnt signaling pathway plays a major role in the regulation of cell proliferation, migration, tissue homeostasis, tumor progression and cancer. This pathway can be antagonized by different proteins such as DKK proteins, which disrupt the initiatory complex (Frizzled–LRP6 complex). Therefore, interruption of its formation could be a promising strategy for the design of Low-density lipoprotein receptor-Related Protein 6 (LRP6) inhibitors. A computational study was conducted in order to assist in the design of inhibitory peptides against LRP6 as co-receptor of frizzled. Twelve fragments as peptide derivatives of natural ligand of LRP6 receptor (DKK1) were designed using the information from the analysis of the DKK1_C/LRP6 complex, hot spot residues and the secondary structure. These fragments were based on cys2 domain of DKK1. The designed peptides were energy minimized by molecular dynamics simulations in the presence and absence of LRP6 receptor and their binding affinities were investigated via molecular docking using ClusPro, HADDOCK and PRODIGY webservers. Finally, the stability and free energy of binding in peptides were calculated by FoldX software. The results showed that four designed peptides had the highest affinity (the interaction energy: ?10.2867, ?10.1388, ?7.94339 and ?7.57536 kcal/mol) to interact with the receptor which showed the most interacting residues and the lowest free energy of binding. Also, the RMSD, RMSF and RoG of the protein–peptide complex exhibited less structural fluctuations which can be linked to the stability of peptides associated to the receptor. These peptides may be considered as candidates for inhibiting Wnt signaling pathway through LRP6 receptor.     

Molecular testing of <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> contaminating tissue allografts recovered from deceased donors

Microbiological screening of tissue allografts is crucial to prevent the transmission of bacterial and fungal infections to transplant recipients. Klebsiella was the most prevalent and resistant contaminating microorganism observed in our setting in the Iranian Tissue Bank. This study was conducted to determine the presence of extended-spectrum β-lactamase (ESBL) genes, antimicrobial resistance patterns of Klebsiella pneumoniae isolates, and their clonal relationships in allograft materials. K. pneumoniae contaminating bone and other tissue allografts recovered from deceased donors were identified and ESBL isolates were detected using a phenotypic confirmatory method. Antimicrobial susceptibility testing was carried out using the disk diffusion method. Distribution of ESBL genes and molecular typing were performed using polymerase chain reaction (PCR) and Repetitive-element (rep-PCR) methods. Of 3828 donated tissues, 51 (1.3%) were found contaminated by K. pneumoniae isolates. Compared to tissue allografts from brain-dead, heart-beating tissue donors, allografts from donors with circulatory cessation were associated with a higher risk of K. pneumoniae contamination [odds ratio (OR), 1.2 (CI 95% 0.9–2.3) (P value < 0.001)]. Half of the isolates produced ESBL, and the rate of susceptibility to cephalosporins was 51%. Among isolates, 22 (43.1%) harbored CTX-M, 31 (60.8%) SHV, and 9 (17.6%) harbored TEM types. The rep-dendrogram indicated that clones having identical or related strains with a similar antibiotype were isolated in the same period. This study provides evidence that a single clone of K. pneumoniae contaminated tissue allografts recovered from many different donors. A single clone found on tissues from several donors suggests contamination of tissues from a single source such as the tissue recovery process and environment. Genomic DNA testing and clonality of contaminating bacteria using molecular methods can focus the epidemiologic investigation on the tissue allograft recovery process including a search for contamination of the tissue recovery room environment, recovery staff, recovery equipment, reagents, solutions and supplies.     

Mesostigmatic mites associated with birds and mammals in Iran. A review

There are diverse relationships between mites and birds or mammals. These mites may play an important role in epizootics and in the perpetuation of some significant diseases. The purpose of this study is to revise the current knowledge of mesostigmatic mites occurring on birds, including their nests and mammals and their substrates, in Iran and to compare the results with other regions of the Palearctic ecozone. This study presents a revised list of 38 species of mesostigmatic mite occuring on birds (17 species) and mammals (24 species) or in their nests/substrates in Iran. Dermanyssus gallinae, Ornithonyssus sylviarum and Parasitus hyalinus were found on both birds and mammals. The species composition of mites reported in Iran was compared with other regions of the Palearctic ecozone. Parasites, specifically those from genera Dermanyssus, Ornithonyssus and Liponyssoides, may be hazardous to human health. Species from these genera were predominant among the reported mites.     

Interaction Between Opioidergic and Dopaminergic Systems on Food Intake in Neonatal Layer Type Chicken

Central regulatory mechanisms for food intake regulation vary among animals. Evidence from animal studies suggests central opioids and dopamine have prominent role on appetite regulation but their interaction(s) have not been studied in layer-type chicken. Thus, in this study six experiments designed to investigate intracerebroventricular (ICV) administration of SCH23390 (D₁ like receptors antagonist), Sulpride (D₂ like receptors antagonist), DAMGO (μ-opioid receptors agonist), DPDPE (δ-opioid receptors agonist), U-50488H (κ-opioid receptors agonist) on feeding behavior in 3 h food deprived neonatal layer-type chickens. In experiment 1, chicks ICV injected with control solution, SCH23390 (2.5 nmol), DAMGO (125 pmol) and their combination (SCH23390 + DAMGO). In experiment 2: control solution, SCH23390 (2.5 nmol), DPDPE (δ-opioid receptors agonist, 40 pmol) and SCH23390 + DPDPE were applied to the birds. In experiment 3, injections were control solution, SCH23390 (2.5 nmol), U-50488H (30 nmol) and SCH23390 + U-50488H. In experiments 4–6 were similar to experiments 1–3 except Sulpride (2.5 nmol) applied instead of SCH23390. Then, cumulative food intake was recorded until 120 min after injection. According to the results, ICV injection of DAMGO (125 pmol) significantly decreased food intake but co-injection of DAMGO + SCH23390 diminished DAMGO-induced hypophagia (P < 0.05). Also, SCH23390 was not able to decrease the DPDPE- and U-50488H-induced hyperphagia (P > 0.05). Furthermore, Sulpride had no role on DAMGO, DPDPE and U-50488H-induced food intake (P > 0.05). These results suggest there is an interaction between opioidergic and dopaminergic systems via μ and D₁ receptors in appetite regulation in chicken.     

Myelin Water Fraction Is Transiently Reduced after a Single Mild Traumatic Brain Injury – A Prospective Cohort Study in Collegiate Hockey Players

Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite ‘compromised white matter integrity’ often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI.     

2-NBDG, a Fluorescent Analogue of Glucose, as a Marker for Detecting Cell Electropermeabilization In Vitro

This study investigated whether molecules spontaneously transported inside cells, like glucose derivatives, can also be used as electropermeabilization markers. Uptake of a fluorescent deoxyglucose derivative (2-NBDG) by normal and electropermeabilized cells in culture was analyzed. 2-NBDG was added to DC-3F cell suspensions and cells, exposed or not to eight square-wave electric pulses of 100-μs duration and of appropriate field amplitude at a repetition frequency of 1 Hz or 5 kHz, were incubated at 37 °C. 2-NBDG uptake was temperature-, concentration- and time-dependent in cells submitted or not to the electric pulses. In spite of significant uptake of 2-NBDG mediated by GLUT transporters into nonpermeabilized cells, the electric pulses significantly increased about ten to hundred times the 2-NBDG uptake into the cells. The increase in the field amplitude from 900 to 1,500 V/cm resulted in a progressive increase of 2-NDBG. Our results show that under the conditions of in vivo exposure duration to FDG and the physiological concentration of d-glucose, electric pulses increased 2-NBDG uptake into electropermeabilized cells. Under our experimental conditions, the percentage of permeabilized cells within the population of cells exposed to electric pulses remained at the same level regardless of the pulse frequency used, 1 Hz or 5 kHz. The findings showed that glucose derivatives can also be used to detect electropermeabilized cells exposed to electric pulses.     

Interplay between SARS-CoV-2-derived miRNAs,immune system,vitamin D pathway and respiratory system

The new coronavirus pandemic started in China in 2019. The intensity of the disease can range from mild to severe, leading to death in many cases. Despite extensive research in this area, the exact molecular nature of virus is not fully recognized; however, according to pieces of evidence, one of the mechanisms of virus pathogenesis is through the function of viral miRNAs. So, we hypothesized that SARS-CoV-2 pathogenesis may be due to targeting important genes in the host with its miRNAs, which involved in the respiratory system, immune pathways and vitamin D pathways, thus possibly contributing to disease progression and virus survival. Potential miRNA precursors and mature miRNA were predicted and confirmed based on the virus genome. The next step was to predict and identify their target genes and perform functional enrichment analysis to recognize the biological processes connected with these genes in the three pathways mentioned above through several comprehensive databases. Finally, cis-acting regulatory elements in 5′ regulatory regions were analysed, and the analysis of available RNAseq data determined the expression level of genes. We revealed that thirty-nine mature miRNAs could theoretically derive from the SARS-CoV-2 genome. Functional enrichment analysis elucidated three highlighted pathways involved in SARS-CoV-2 pathogenesis: vitamin D, immune system and respiratory system. Our finding highlighted genes' involvement in three crucial molecular pathways and may help develop new therapeutic targets related to SARS-CoV-2.