ABC (ATP-binding cassette) transporters are a large superfamily of integral membrane proteins involved in the cellular export or import of a wide variety of different substances, including ions, lipids, cyclic nucleotides, peptides, and proteins. ABC transporters are systemically classified into eight subfamilies by sequence similarity, i.e., ABCA (ABC1), ABCB (MDR/TAP), ABCC (MRP/CFTR), ABCD (ALD), ABCE (RNAseLI/OABP), ABCF (GCN20), ABCG (White) and ANSA subclass. In general, the transmembrane part of ABC transporters contains a polar channel formed by two homologous domains, each usually consisting of five (uptake transporters) or six (efflux transporters) transmembrane alpha-helices (Ref.1 & 2). Typically, ABC proteins are relatively specific for a[..]
HBV(Hepatitis B virus) is a member of the family Hepadnaviridae. It is a hepatotropic non-cytopathic DNA virus and is a major cause of acute and chronic hepatitis in humans. As HBV itself is currently viewed as a non-cytopathic virus, the liver pathology associated with hepatitis B is mainly thought to be due to immune responses directed against HBV antigens. The outcome of HBV infection is the result of complex interactions between replicating HBV and the immune system.Both innate and adaptive arms of the immune system are generally involved in responding to the viral infection, with innate responses being important for control of viral replication and dissemination very early after infection, as well as for timely orchestration of virus-specific adaptive responses.[..]
Steroid hormones are lipophilic, low-molecular weight compounds derived from Cholesterol that play important physiological roles. The steroid hormones are synthesized mainly by Endocrine Glands such as the the Adrenal Cortex and the Gonads (Ovary and Testes), and are then released into the blood circulation. There are five major classes of steroid hormones. They are the (i) Glucocorticoids (Anti-Stress Hormones), Cortisol is the major representative in most mammals; Mineralocorticoids (Na+ Uptake Regulators), Aldosterone being most prominent; Androgens (Male Sex Hormones), such as Testosterone; Estrogens (Female Sex Hormones), including Estrodiol and Estrone; and, Progestogens (Progestational hormones), such as Progesterone. The Adrenal Cortex is responsible for[..]
AMLs (Acute Myeloid Leukemias) are characterized with chromosomal translocations resulting in the formation of fusion proteins. Understanding PML (Acute Promyelocytic Leukemia Inducer) function has become an area of intense research because of its involvement in the pathogenesis of APL (Acute Promyelocytic Leukemia), a distinct subtype of Myeloid Leukemia. In the vast majority of APL case studies, the PML gene (on Chromosome-15) fuses to the RAR-Alpha gene (Retinoic Acid Receptor-Alpha) (on Chromosome-17) as a consequence of reciprocal and balanced chromosomal translocations. In the t(15;17) chromosomal translocation, which is specific for APL, PML is found in a reciprocal translocation with the RAR-Alpha resulting in the formation of PML-RAR-Alpha and RAR-Alpha-PML[..]
Vitamin A and its analogs, collectively termed retinoids, have a profound effect on cell growth, differentiation, apoptosis, and morphogenesis. Retinol, the lipid-soluble vitamin A, is an absolute requirement for normal growth, vision and differentiation of epithelial tissues in mammals. Retinol must be obtained directly through dietary intake, but may also be derived in its provitamin A forms obtained through dietary carotenoids (Ref.1 and 2). Retinoids bind to six distinct nuclear receptors in mammals and regulate the expression of target genes. The Retinoic Acid Receptors (RARs) and Retinoid X Receptors are among the most intensely studied nuclear hormone receptors. RARs are ligand-controlled transcription factors that function as heterodimers with RXRs to regulate[..]
Retinoic Acid, a lipophilic molecule and a metabolite of Vitamin-A (all-trans-Retinol), affects gene transcription and modulates a wide variety of biological processes like Cell Proliferation, Differentiation, including Apoptosis. Retinoic Acid mediated gene transcription depends on the rate of transport of Retinoic Acid to target cells and the timing of exposure of Retinoic Acid to RARs (Retinoic Acid Receptors) in the target tissues. The all-trans-Retinoic Acid, the Carboxylic Acid form of Vitamin-A is of biological significance since it has high circulating levels than other isomers of Retinoic Acid. The targets of all-trans-Retinoic Acid and RARs include a multitude of Structural genes, Oncogenes, Transcription Factors and Cytokines. Although biologically active[..]
The ESRs (Estrogen Receptors) are ligand-dependent transcription factors and are important Nuclear Hormone Receptors that act as regulators of cell growth, differentiation and malignant transformation. Transcriptional activation by ESRs is accomplished through specific and general cofactor complexes that assemble with the receptor at target promoters to regulate transcription. The chief ligand for ESR is the ovarian steroid hormone Estrogen, which has a primary role in the establishment and maintenance of reproductive function (Ref.1). Naturally occurring forms of Estrogen are Estradiol, Estriol, and Estrone. Estradiol is the most commonly occurring form of Estrogen in non-pregnant women. Binding of Estrogen to the ESR promotes a conformational change in the receptor[..]
C. perfringens (Clostridium perfringens) is a common Gram-positive endosporeforming, non-motile, rod-shaped, anaerobic bacillus and is known to produce a variety of toxins and enzymes that are responsible for severe myonecrotic lesions. Spores survive cooking and then germinate and multiply during storage at ambient temperature, slow cooling, or inadequate re-warming. Though its natural habitats are soil and the intestinal tracts of humans and animals, it has been isolated from virtually every environment examined for its presence. C. perfringens is a human pathogen, capable of causing illness either through wound infection or food-borne intoxication (Ref.1). Alpha-toxin is regarded as the most medically important toxin produced by C. perfringens; it is the toxin[..]
Members of genus Clostridium are Gram-positive, spore-forming rods that are anaerobic. These bacteria includes both motile and non-motile bacillus with ubiquitous distribution in nature and are especially fond of soil. Clostridium shows optimimum growth when plated on blood agar at human body temperatures. When the environment becomes stressed, however, the bacteria produce spores that tolerate the extreme conditions that the active bacteria cannot. In their active form, these bacteria secrete powerful exotoxins that are responsible for such diseases as Tetanus, Botulism, and Gas gangrene (Ref.1). The solventogenic Clostridia like C. acetobutylicum (Clostridium acetobutylicum) continue to be the subject of numerous studies, including recent efforts to apply[..]
E. coli (Escherichia coli) is Gram-negative with external flagella. The strain E. coli CFT073 are uropathogenic and this group is responsible for Acute Cystitis and Pyelonephritis. E. coli is a remarkably diverse species because some strains living as harmless commensals in animal intestines, whereas other distinct genotypes including the enteropathogenic, enterohemorrhagic, enteroinvasive, enterotoxigenic, and enteroaggregative E. coli causes significant morbidity and mortality as human intestinal pathogens (Ref.1). Extra-intestinal E. coli are another varied group of life-threatening pathogens of this manifestly versatile species. This latter group of pathogens includes distinct clonal groups responsible for neonatal meningitis/sepsis and urinary tract infections.[..]
The bacterium E. coli (Escherichia coli) is one of the best and most thoroughly studied free-living organisms. It is also a remarkably diverse species because some E. coli strains live as harmless commensals in animal intestines, whereas other distinct genotypes including the enteropathogenic, enterohemorrhagic, enteroinvasive, enterotoxigenic, and enteroaggregative E. coli causes significant morbidity and mortality as human intestinal pathogens (Ref.1). Extra-intestinal E. coli are another varied group of life-threatening pathogens of this manifestly versatile species. This latter group of pathogens includes distinct clonal groups responsible for neonatal meningitis/sepsis and urinary tract infections. E. coli is Gram-negative, flagellated and members of the strain E.[..]
The bacterium E. coli O157 (Escherichia coli O157) is a worldwide threat to public health and are implicated in many outbreaks of Haemorrhagic Colitis, some of which included fatalities caused by Haemolytic Uraemic Syndrome. The severity of disease, the lack of effective treatment and the potential for large-scale outbreaks from contaminated food supplies have propelled intensive research on the pathogenesis and detection of E. coli O157 strains and these include candidate virulence factors, alternative metabolic capacities, several prophages and other new functions-all of which could be targets for surveillance (Ref.1). The enterohemorrhagic E. coli O157 EDL933 is Gram-negative having external flagella. The involvement of D- and L-Amino acid metabolism like L-Serine,[..]
