Possible Molecular Mediators Involved and Mechanistic Insight into Fibromyalgia and Associated Co-morbidities

Neurochemical Research - Fibromyalgia is a chronic complex syndrome of non-articulate origin characterized by musculoskeletal pain, painful tender points, sleep problems and co-morbidities...     

Breakpoint mapping of a novel de novo translocation t(X;20)(q11.1;p13) by positional cloning and long read sequencing

Disease associated chromosomal rearrangements often have break points located within disease causing genes or in their vicinity. The purpose of this study is to characterize a balanced reciprocal translocation in a girl with intellectual disability and seizures by positional cloning and whole genome sequencing. The translocation was identification by G- banding and confirmed by WCP FISH. Fine mapping using BAC clones and whole genome sequencing using Oxford nanopore long read sequencing technology for a 1.46 X coverage of the genome was done. The positional cloning showed split signals with BAC RP11-943 J20. Long read sequencing analysis of chimeric reads carrying parts of chromosomes X and 20 helped to identify the breakpoints to be in intron 2 of ARHGEF9 gene on Xp11.1 and on 20p13 between RASSF2 and SLC23A2 genes. This is the first report of translocation which successfully delineated to single base resolution using Nanopore sequencing. The genotype-phenotype correlation is discussed.     

Mapping quantitative trait loci associated with southern leaf blight resistance in maize (Zea mays L.)

Southern leaf blight (SLB) caused by the fungus Cochliobolus heterostrophus (Drechs.) Drechs. is a major foliar disease of maize worldwide. Our objectives were to identify quantitative trait loci (QTL) for resistance to SLB and flowering traits in recombinant inbred line (RIL) population derived from the cross of inbred lines LM5 (resistant) and CM140 (susceptible). A set of 207 RILs were phenotyped for resistance to SLB at three time intervals for two consecutive years. Four putative QTL for SLB resistance were detected on chromosomes 3, 8 and 9 that accounted for 54% of the total phenotypic variation. Days to silking and anthesis–silking interval (ASI) QTL were located on chromosomes 6, 7 and 9. A comparison of the obtained results with the published SLB resistance QTL studies suggested that the detected bins 9.03/02 and 8.03/8.02 are the hot spots for SLB resistance whereas novel QTL were identified in bins 3.08 and 8.01/8.04. The linked markers are being utilized for marker‐assisted mobilization of QTL conferring resistance to SLB in elite maize backgrounds. Fine mapping of identified QTL will facilitate identification of candidate genes underlying SLB resistance.     

How do plants defend themselves against pathogens-Biochemical mechanisms and genetic interventions

In agro-ecosystem, plant pathogens hamper food quality, crop yield, and global food security. Manipulation of naturally occurring defense mechanisms in host plants is an effective and sustainable approach for plant disease management. Various natural compounds, ranging from cell wall components to metabolic enzymes have been reported to protect plants from infection by pathogens and hence provide specific resistance to hosts against pathogens, termed as induced resistance. It involves various biochemical components, that play an important role in molecular and cellular signaling events occurring either before (elicitation) or after pathogen infection. The induction of reactive oxygen species, activation of defensive machinery of plants comprising of enzymatic and non-enzymatic antioxidative components, secondary metabolites, pathogenesis-related protein expression (e.g. chitinases and glucanases), phytoalexin production, modification in cell wall composition, melatonin production, carotenoids accumulation, and altered activity of polyamines are major induced changes in host plants during pathogen infection. Hence, the altered concentration of biochemical components in host plants restricts disease development. Such biochemical or metabolic markers can be harnessed for the development of “pathogen-proof” plants. Effective utilization of the key metabolites-based metabolic markers can pave the path for candidate gene identification. This present review discusses the valuable information for understanding the biochemical response mechanism of plants to cope with pathogens and genomics-metabolomics-based sustainable development of pathogen proof cultivars along with knowledge gaps and future perspectives to enhance sustainable agricultural production.     

Role of arterial blood gas (ABG) as a valuable assessment tool of disease severity in SARS-CoV-2 patients

BackgroundCOVID-19 is caused by a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The foremost predominant complication of SARS-CoV-2 is arterial hypoxemia thereby disturbing lung compliance, requiring mechanical ventilation. The aim of the current research study is to analyze role of ABG as a valuable assessment tool of disease severity in SARS-CoV-2 patients.Methods170 arterial blood samples were collected from patients admitted in Intensive Care Unit (ICU) of Sri Guru Ram Das Charitable Hospital, Amritsar. They were analyzed for arterial blood gas using ABG analyzer. Parameters of ABG such as pH, pCO2, HCO3, O2 saturation, ionized calcium (iCa) and calculated ionized calcium (at pH 7.4) was calculated for all the samples.ResultsContinuous variables were described as medians with interquartile ranges (IQRs) and categorical variables as percentages and frequencies. Spearman correlation test was done for calculation of correlation between pH and other ABG parameters. Analysis of arterial blood gas revealed significant negative correlation (p<0.05) between pH and pCO2 and significant positive correlation (p<0.05) between pH and HCO3 and between pH and delta ionized calcium. Low levels (98.2%) of ionized calcium were observed while monitoring the ABG findings though weak negative correlation (p<0.05) was observed between pH and iCa.ConclusionsOur study suggests that ABG analysis acts as a momentous indicator for critically ill patients admitted in Intensive Care Unit (ICU). Estimation of iCa in this critical care setting acts as a distinctive biochemical feature of SARS-CoV-2 disease, as an initial assessment tool, for hypocalcemia.     

Enhanced binding of a rationally designed peptide ligand of concanavalin a arises from improved geometrical complementarity

The structural basis of affinity enhancement was addressed by analyzing the interactions between concanavalin A and the carbohydrate-mimicking peptide ligands. Based on the crystal structures of concanavalin A in complex with these peptides [Jain, D., Kaur, K. J., Sundaravadivel, B., and Salunke, D. M. (2000) J. Biol. Chem. 275, 16098-16102; Jain, D., Kaur, K. J., and Salunke, D. M. (2001) Biophys. J. 80, 2912-2921], a high-affinity analogue was designed. This analogue (acetyl-MYWYPY-amide) binds to the lectin with 32-fold enhanced affinity compared to the corresponding precursor peptides. The crystal structure of concanavalin A bound to the designed peptide has been determined. A peptide molecule binds to each of the crystallographically independent monomers of the tetrameric lectin. The four bound peptide molecules exhibit two major conformations both of which are extended. Unlike in the case of other concanavalin A binding peptides, the structural variations within different conformers of this analogue are marginal. It is apparent that the deletion of the structurally variable region of the larger peptides has led to an improved complementarity and increased buried surface area in the case of the designed peptide. The crystal structure also showed the formation of two backbone hydrogen bonds between the ligand and the ligate which were not present in the complexes of the precursor peptides. The observed structural features adequately explain the enhanced binding of the designed analogue.     

Biochemical mechanism of combined effect of ethambutol and sparfloxacin against Mycobacterium smegmatis

M. smegmatis cells grown in the presence of combination of ethambutol (EMB) and sparfloxacin (SPX) had decreased level of total cellular lipids as compared to control as well as cells grown in the presence of sub-inhibitory concentration (MIC50) of individual drugs. Amongst various phospholipids analyzed, maximum decrease was observed in the content of phosphatidylinositolmannosides (PIMs) of the cells grown in combination of EMB and SPX. In contrast, the subcellular distribution of phospholipids revealed a significant increase in PIMs content of both cell wall and cell membrane of the cells grown in the presence of combination of drugs as compared to control as well as individual drugs. Mycolic acids of M. smegmatis cells were found to be main targets as combination of drugs resulted in significant decrease in total cellular as well as cell wall mycolic acids as compared to control and individual drugs. Changed lipid composition of M. smegmatis cells grown in the presence of MIC50 of EMB, SPX and combination resulted in significant surface changes as was evident from decreased limiting fluorescence (Fmax) intensity of 1-anilinonaphthalene-8-sulfonate (ANS). Thus, the results of this study suggested that ethambutol and sparfloxacin in combination exerted their antimycobacterial effect principally due to their action on phosphatidylinositolmannosides (PIMs) and mycolic acids, which form the permeability barrier of mycobacteria.     

Immunological defect in leprosy patients: altered T-lymphocyte signals

The early events of activation were studied in paucibacillary (TT/BT) and multibacillary (BL/LL) leprosy patients by stimulation of their lymphocytes with mitogenic agents (calcium ionophore A23187/PMA) and Micobacterium leprae antigen (PGL-1). Maximum proliferation in response to PMA/A23187 and PGL-1 was observed in the BT/TT patients and the control group, respectively. Inositol triphosphate (IP3) and calcium were constitutively elevated in BT/TT and LL/BL patients. PMA/A23187 caused an increase in both IP3 and [Ca2+]i in BT/TT patients and controls. PGL-1 marginally increased IP3 levels in BT/TT patients. In the LL/BL patients, although PMA/A23187 increased IP3 levels, but no change was seen in [Ca2+]i, PGL-1 had no effect. Protein kinase C levels were seen to be associated with particulate fractions in BT/TT patients and were found to increase further in response to PMA/A23187. PGL-1 did not increase translocation of protein kinase C in controls or LL/BL patients. A preactivated and sensitised state of T-lymphocytes was observed in BT/TT patients, responsive to antigen and mitogens, whereas the cells of LL/BL patients were unresponsive to PGL-1. The altered signal transduction events characterised in the MB patients thus correlate well with the anergic state of their cells.     

ATM and the catalytic subunit of DNA-dependent protein kinase activate NF-kappaB through a common MEK/extracellular signal-regulated kinase/p90(rsk) signaling pathway in response to distinct forms of DNA damage

We have identified a novel pathway of ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK) signaling that results in nuclear factor kappaB (NF-kappaB) activation and chemoresistance in response to DNA damage. We show that the anthracycline doxorubicin (DOX) and its congener N-benzyladriamycin (AD 288) selectively activate ATM and DNA-PK, respectively. Both ATM and DNA-PK promote sequential activation of the mitogen-activated protein kinase (MAPK)/p90(rsk) signaling cascade in a p53-independent fashion. In turn, p90(rsk) interacts with the IkappaB kinase 2 (IKK-2) catalytic subunit of IKK, thereby inducing NF-kappaB activity and cell survival. Collectively, our findings suggest that distinct members of the phosphatidylinositol kinase family activate a common prosurvival MAPK/IKK/NF-kappaB pathway that opposes the apoptotic response following DNA damage.