Mitochondrial dysfunction in perinatal asphyxia: role in pathogenesis and potential therapeutic interventions

Molecular and Cellular Biochemistry - Perinatal asphyxia (PA)-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and long-term sequelae such as spastic...     

Daboxin P,a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity

In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A₂ activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca⁺² binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A₂ enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.     

Rhamnose Biosynthesis Pathway Supplies Precursors for Primary and Secondary Metabolism in Saccharopolyspora spinosa

Rhamnose is an essential component of the insect control agent spinosad. However, the genes coding for the four enzymes involved in rhamnose biosynthesis in Saccharopolyspora spinosa are located in three different regions of the genome, all unlinked to the cluster of other genes that are required for spinosyn biosynthesis. Disruption of any of the rhamnose genes resulted in mutants with highly fragmented mycelia that could survive only in media supplemented with an osmotic stabilizer. It appears that this single set of genes provides rhamnose for cell wall synthesis as well as for secondary metabolite production. Duplicating the first two genes of the pathway caused a significant improvement in the yield of spinosyn fermentation products.     

In silico synteny based comparative genomics approach for identification and characterization of novel therapeutic targets in Chlamydophila pneumoniae

Chlamydophila pneumoniae is one of the most important and well studied gram negative bacterial strain with respect to community acquired pneumonia and other respiratory diseases like Chronic obstructive pulmonary disease (COPD), Chronic asthma, Alzheimer''s disease, Atherosclerosis and Multisclerosis which have a great potential to infect humans and many other mammals. According to WHO prediction, COPD is to become the third leading cause of death by 2030. Unfortunately, the molecular mechanisms leading to chronic infections are poorly understood and the difficulty in culturing C pneumoniae in experimental conditions and lack of entirely satisfactory serological methods for diagnosis is also a hurdle for drug discovery and development. We have performed an insilico synteny based comparative genomics analysis of C pneumoniae and other eight Chlamydial organisms to know the potential of C pneumoniae which cause COPD but other Chlamydial organisms lack in potential to cause COPD though some are involved in human pathogenesis. We have identified total 354 protein sequences as non-orthologous to other Chlamydial organisms, except hypothetical proteins 70 were found functional out of which 60 are non homologous to Homo sapiens proteome and among them 18 protein sequences are found to be essential for survival of the C pneumoniae based on BLASTP search against DEG database of essential genes. CELLO analysis results showed that about 80% proteins are found to be cytoplasmic, Among which 5 were found as bacterial exotoxins and 2 as bacterial endotoxins, remaining 11 proteins were found to be involved in DNA binding, RNA binding, catalytic activity, ATP binding, oxidoreductase activity, hydrolase activity and proteolysis activity. It is expected that our data will facilitate selection of C pneumoniae proteins for successful entry into drug design pipelines.     

Chromosomal polymorphism in Drosophila nasuta. III. Inverted gene arrangements in South Indian populations.

Inversion polymorphism, including a total of 33 inverted gene orders, was studied in South Indian populations of D. nasuta nasuta. Of these, the X chromosome has one, chromosome 2 has 10, and chromosome 3 has 22 inversions. D. nasuta nasuta has simple, tandem, included, overlapping, and complex types of paracentrics in its polymorphic system. The phylogenetic considerations of these gene orders are discussed.     

Rapid Accumulation of Endogenous Tau Oligomers in a Rat Model of Traumatic Brain Injury: POSSIBLE LINK BETWEEN TRAUMATIC BRAIN INJURY AND SPORADIC TAUOPATHIES*

Traumatic brain injury (TBI) is a serious problem that affects millions of people in the United States alone. Multiple concussions or even a single moderate to severe TBI can also predispose individuals to develop a pathologically distinct form of tauopathy-related dementia at an early age. No effective treatments are currently available for TBI or TBI-related dementia; moreover, only recently has insight been gained regarding the mechanisms behind their connection. Here, we used antibodies to detect oligomeric and phosphorylated Tau proteins in a non-transgenic rodent model of parasagittal fluid percussion injury. Oligomeric and phosphorylated Tau proteins were detected 4 and 24 h and 2 weeks post-TBI in injured, but not sham control rats. These findings suggest that diagnostic tools and therapeutics that target only toxic forms of Tau may provide earlier detection and safe, more effective treatments for tauopathies associated with repetitive neurotrauma.