Human mitochondrial function during cardiac growth and development

Little information is presently available concerning mitochondrial respiratory and oxidative phosphorylation function in the normal human heart during growth and development. We investigated the levels of specific mitochondrial enzyme activities and content during cardiac growth and development from the early neonatal period (10-20 days) to adulthood (67 years). Biochemical analysis of enzyme specific activities and content and mitochondrial DNA (mtDNA) copy number was performed with left ventricular tissues derived from 30 control individuals. The levels of cytochrome c oxidase (COX) and complex V specific activity, mtDNA copy number and COX subunit II content remained unchanged in contrast to increased citrate synthase (CS) activity and content. The developmental increase in CS activity paralleled increasing CS polypeptide content, but was neither related to overall increases in mitochondrial number nor coordinately regulated with mitochondrial respiratory enzyme activities. Our findings of unchanged levels of cardiac mitochondrial respiratory enzyme activity during the progression from early childhood to older adult contrasts with the age-specific regulation found with CS, a Krebs cycle mitochondrial enzyme.     

Regulation of PTEN translation by PI3K signaling maintains pathway homeostasis

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Microalgae as multi-functional options in modern agriculture: current trends,prospects and challenges

Algae are a group of ubiquitous photosynthetic organisms comprising eukaryotic green algae and Gram-negative prokaryotic cyanobacteria, which have immense potential as a bioresource for various industries related to biofuels, pharmaceuticals, nutraceuticals and feed. This fascinating group of organisms also has applications in modern agriculture through facilitating increased nutrient availability, maintaining the organic carbon and fertility of soil, and enhancing plant growth and crop yields, as a result of stimulation of soil microbial activity. Several cyanobacteria provide nitrogen fertilization through biological nitrogen fixation and through enzymatic activities related to interconversions and mobilization of different forms of nitrogen. Both green algae and cyanobacteria are involved in the production of metabolites such as growth hormones, polysaccharides, antimicrobial compounds, etc., which play an important role in the colonization of plants and proliferation of microbial and eukaryotic communities in soil. Currently, the development of consortia of cyanobacteria with bacteria or fungi or microalgae or their biofilms has widened their scope of utilization. Development of integrated wastewater treatment and biomass production systems is an emerging technology, which exploits the nutrient sequestering potential of microalgae and its valorisation. This review focuses on prospects and challenges of application of microalgae in various areas of agriculture, including crop production, protection and natural resource management. An overview of the recent advances, novel technologies developed, their commercialization status and future directions are also included.     

Thermostabilization of protective antigen—the binding component of anthrax lethal toxin

Protective antigen (PA) is the binding component of anthrax lethal toxin produced by Bacillus anthracis, and constitutes a major ingredient of the vaccine against anthrax. PA and lethal factor when added together are cytolytic to mouse macrophages and J774G8 macrophage cell line. This in vitro lethal toxicity assay is very useful in understanding the molecular mechanism of action of lethal toxin. Effective utilization of PA is, however, hampered due to its thermolability. On prolonged storage at 37 ° C, PA was found to lose its activity almost completely. The effect of solvent additives like trehalose, sorbitol, xylitol, sodium citrate and magnesium sulphate on the thermal stabilization of PA was examined. The results indicated an increase in the stability of PA when the incubation at 37 ° C was carried out in the presence of solvent additives used in the 1–3 M range. Magnesium sulphate helped retain the activity up to 82.7% against the control in which no additive was used, as judged by cytolytic assay using J774G8 macrophage cell line. Trehalose or sodium citrate also showed an appreciable protection of PA activity, while sorbitol or xylitol were not very effective. Competitive binding assay using radiolabeled PA showed that PA had lost capacity of binding to macrophage cells on prolonged incubation at 37 ° C. Circular dichroism results at 4, 18 and 37 ° C indicated an increase in secondary structure at 37 ° C relative to that at 4 or 18 ° C, supporting the activity data.     

Studies on some trace and minor elements in blood

Blood is one of the widely used specimens for biological trace element research because of its biological significance and ease of sampling. We have conducted a study of the blood of the Kalpakkam township population for trace and minor elements. For this purpose, analytical methods have been developed and standardized in our laboratory for the elemental analysis of blood plasma and red cells. Inductively coupled plasma-mass spectrometry (ICP-MS), a relatively new technique, has been applied for the analysis of trace elements. Details regarding spectral interference and matrix interference encountered in the analysis of blood and the methods of correcting them have been discussed. Flame atomic absorption spectrometry (AAS)/atomic emission spectrometry (AES) has been applied for the determination of minor elements. Precision and accuracy of these methods have also been discussed.     

Some quantitative changes observed in Philosamia ricini pupal haemolymph during metamorphosis

1. The quantitative variations of the concentrations of uric acid, citrate, nucleic acids and total and acid-soluble phosphorus in the pupal haemolymph of Philosamia ricini during metamorphosis have been studied. 2. The mean value for total nitrogen in the haemolymph and total loss in weight of the insects during metamorphosis have also been recorded.     

Role of infection in the pathogenesis of rheumatic diseases

Advanced immunological technology has revealed immunological abnormalities not only in some chronic and autoimmune connective tissue disorders but also in conditions like infective arthritis where infection apparently seems to play the only role. On the other hand role of infection in the pathogenesis of some connective tissue disorders has recently gained much importance from the observation of clinical, pathological and immunological similarities between these diseases and certain infectious diseases occurring in animal models. Meanwhile, knowledge gained into human leucocyte-A system and its association with certain diseases opens another angle in etiopathogenesis of certain rheumatic diseases. It has been postulated that adaptive mechanism of a microbe or the binding between the human leucocyte-A molecule and carbohydrate moiety of a microbe may set up an autoimmune reaction and in the presence of some triggering factors in the environment may lead on to disease manifestations. An attempt has been made to discuss the role of infection in the outcome of rheumatic diseases such as septic arthritis, polyarteritis nodosa, rheumatic fever, enteropathic arthritis, ankylosing spondylitis, rheumatoid arthritis and systemic lupus erythematoses in genetically susceptible individuals producing immunological abnormalities.     

Effects of benzo[a]pyrene-deoxyguanosine lesions on DNA methylation catalyzed by EcoRII DNA methyltransferase and on DNA cleavage effected by EcoRII restriction endonuclease

DNA methylation is an important cellular mechanism for controlling gene expression. Whereas the mutagenic properties of many DNA adducts, e.g., those arising from polycyclic aromatic hydrocarbons, have been widely studied, little is known about their influence on DNA methylation. We have constructed site-specifically modified 18-mer oligodeoxynucleotide duplexes containing a pair of stereoisomeric adducts derived from a benzo[a]pyrene-derived diol epoxide [(+)- and (-)-r7,t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene, or B[a]PDE] bound to the exocyclic amino group of guanine. The adducts, either (+)- or (-)-trans-anti-B[a]P-N(2)-dG (G*), positioned either at the 5'-side or the 3'-side deoxyguanosine residue in the recognition sequence of EcoRII restriction-modification enzymes (5'-...CCA/TGG...) were incorporated into 18-mer oligodeoxynucleotide duplexes. The effects of these lesions on complex formation and the catalytic activity of the EcoRII DNA methyltransferase (M.EcoRII) and EcoRII restriction endonuclease (R.EcoRII) were investigated. The M.EcoRII catalyzes the transfer of a methyl group to the C5 position of the 3'-side cytosine of each strand of the recognition sequence, whereas R.EcoRII catalyzes cleavage of both strands. The binding of R.EcoRII to the oligodeoxynucleotide duplexes and the catalytic cleavage were completely abolished when G was positioned at the 3'-side dG position (5'-...CCTGG*...). When G* was at the 5'-side dG position, binding was moderately diminished, but cleavage was completely blocked. In the case of M.EcoRII, binding is diminished by factors of 5-30 but the catalytic activity was either abolished or reduced 4-80-fold when the adducts were located at either position. Somewhat smaller effects were observed with hemimethylated oligodeoxynucleotide duplexes. These findings suggest that epigenetic effects, in addition to genotoxic effects, need to be considered in chemical carcinogenesis initiated by B[a]PDE, since the inhibition of methylation may allow the expression of genes that promote tumor development.