A critical life-supporting role for cystathionine γ-lyase in the absence of dietary cysteine supply

This study examined the important relationship between cystathionine γ-lyase (CSE) functionality and cysteine supply for normal growth and life span. Mice with a targeted deletion of the CSE gene (CSE-KO) were fed a cysteine-limited diet and their growth and survival patterns as well as levels of cysteine, homocysteine, glutathione, and hydrogen sulfide (H2S) were measured. CSE-KO mice fed a cysteine-limited diet exhibited growth retardation; decreased levels of cysteine, glutathione, and H2S; and increased plasma homocysteine level. However, histological examinations of liver did not reveal any abnormality and plasma levels of aspartate aminotransferase, alanine aminotransferase, and albumin were normal in these animals. No CSE-KO mice survived after 12 weeks of feeding with the cysteine-limited diet. Supplementation of H2S to the CSE-KO mice failed to reverse the aforementioned abnormalities. On the other hand, supplementation of cysteine in the drinking water of the CSE-KO mice significantly increased plasma cysteine and glutathione levels. This eventually led to an increase in body weight and rescued the animals from death. In conclusion, CSE is critical for cysteine biosynthesis through the transsulfuration pathway and the combination of CSE deficiency and lack of dietary cysteine supply would threaten life sustainability.     

Giant cell arteritis: immune and vascular aging as disease risk factors

Susceptibility for giant cell arteritis increases with chronological age, in parallel with age-related restructuring of the immune system and age-induced remodeling of the vascular wall. Immunosenescence results in shrinkage of the naïve T-cell pool, contraction of T-cell diversity, and impairment of innate immunity. Aging of immunocompetent cells forces the host to take alternative routes for protective immunity and confers risk for pathogenic immunity that causes chronic inflammatory tissue damage. Dwindling immunocompetence is particularly relevant as the aging host is forced to cope with an ever growing infectious load. Immunosenescence coincides with vascular aging during which the arterial wall undergoes dramatic structural changes and medium and large arteries lose their pliability and elasticity. On the molecular level, elastic fibers deteriorate and matrix proteins accumulate biochemical modifications. Thus, the aging process impacts the two major biologic systems that liaise to promote giant cell arteritis; the immune system and the vessel wall niche.     

Evaluation of Ionotropic Cross-Linked Chitosan/Gelatin B Microspheres of Tramadol Hydrochloride

Microspheres of tramadol hydrochloride (TM) for oral delivery were prepared by complex coacervation method without the use of chemical cross-linking agents such as glutaraldehyde to avoid the toxic reactions and other undesirable effects of the chemical cross-linking agents. Alternatively, ionotropic gelation was employed by using sodium-tripolyphosphate as cross-linking agent. Chitosan and gelatin B were used as polymer and copolymer, respectively. All the prepared microspheres were subjected to various physicochemical studies, such as drug–polymer compatibility by thin layer chromatography (TLC) and Fourier transform infrared (FTIR) spectroscopy, surface morphology by scanning electron microscopy, frequency distribution, drug entrapment efficiency, in vitro drug release characteristics and release kinetics. The physical state of drug in the microspheres was determined by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). TLC and FTIR studies indicated no drug–polymer incompatibility. All the microspheres showed initial burst release followed by a fickian diffusion mechanism. DSC and XRD analysis indicated that the TM trapped in the microspheres existed in an amorphous or disordered-crystalline status in the polymer matrix. From the preliminary trials, it was observed that it may be possible to formulate TM microspheres by using biodegradable natural polymers such as chitosan and gelatin B to overcome the drawbacks of TM and to increase the patient compliance.     

Activation of anti-tumor immune response and reduction of regulatory T cells with Mycobacterium indicus pranii (MIP) therapy in tumor bearing mice

Background

Role of immune system in protecting the host from cancer is well established. Growing cancer however subverts immune response towards Th2 type and escape from antitumor mechanism of the host. Activation of both innate and Th1 type response is crucial for host antitumor activity. In our previous study it was found, that Mycobacterium indicus pranii (MIP) also known as M. w induces Th1 type response and activates macrophages in animal model of tuberculosis. Hence, we studied the immunotherapeutic potential of MIP in mouse tumor model and the underlying mechanisms for its antitumor activity.

Methodology and Principal Findings

Tumors were implanted by injecting B16F10 melanoma cells subcutaneously into C57BL/6 mice. Using the optimized dose and treatment regimes, anti-tumor efficacy of heat killed MIP was evaluated. In MIP treated group, tumor appeared in only 50–60% of mice, tumor growth was delayed and tumor volume was less as compared to control. MIP mediated immune activation was analysed in the tumor microenvironment, tumor draining lymph node and spleen. Induction of Th1 response and higher infiltration of immune cells in the tumor microenvironment was observed in MIP treated mice. A large fraction of these immune cells were in activated state as confirmed by phenotypic and functional analysis. Interestingly, percentage of Treg cells in the tumor milieu of treated mice was less. We also evaluated efficacy of MIP along with chemotherapy and found a better response as compared to chemotherapy alone.

Conclusion

MIP therapy is effective in protecting mice from tumor. It activates the immune cells, increases their infiltration in tumor, and abrogates tumor mediated immune suppression.     

Conservation of inter-residue interactions and prediction of folding rates of domain repeats

Domains are the main structural and functional units of larger proteins. They tend to be contiguous in primary structure and can fold and function independently. It has been observed that 10–20% of all encoded proteins contain duplicated domains and the average pairwise sequence identity between them is usually low. In the present study, we have analyzed the structural similarity between domain repeats of proteins with known structures available in the Protein Data Bank using structure-based inter-residue interaction measures such as the number of long-range contacts, surrounding hydrophobicity, and pairwise interaction energy. We used RADAR program for detecting the repeats in a protein sequence which were further validated using Pfam domain assignments. The sequence identity between the repeats in domains ranges from 20 to 40% and their secondary structural elements are well conserved. The number of long-range contacts, surrounding hydrophobicity calculations and pairwise interaction energy of the domain repeats clearly reveal the conservation of 3-D structure environment in the repeats of domains. The proportions of mainchain–mainchain hydrogen bonds and hydrophobic interactions are also highly conserved between the repeats. The present study has suggested that the computation of these structure-based parameters will give better clues about the tertiary environment of the repeats in domains. The folding rates of individual domains in the repeats predicted using the long-range order parameter indicate that the predicted folding rates correlate well with most of the experimentally observed folding rates for the analyzed independently folded domains.     

Molecular recognition of human eosinophil-derived neurotoxin (RNase 2) by placental ribonuclease inhibitor

Placental ribonuclease inhibitor (RI) binds diverse mammalian RNases with dissociation constants that are in the femtomolar range. Previous studies on the complexes of RI with RNase A and angiogenin revealed that RI utilises largely distinctive interactions to achieve high affinity for these two ligands. Here we report a 2.0 angstroms resolution crystal structure of RI in complex with a third ligand, eosinophil-derived neurotoxin (EDN), and a mutational analysis based on this structure. The RI-EDN interface is more extensive than those of the other two complexes and contains a considerably larger set of interactions. Few of the contacts present in the RI-angiogenin complex are replicated; the correspondence to the RI-RNase A complex is somewhat greater, but still modest. The energetic contributions of various interface regions differ strikingly from those in the earlier complexes. These findings provide insight into the structural basis for the unusual combination of high avidity and relaxed stringency that RI displays.     

Polypyrimidine tract binding protein blocks the 5' splice site-dependent assembly of U2AF and the prespliceosomal E complex

Polypyrimidine tract binding protein (PTB) represses some alternatively spliced exons by direct occlusion of splice sites. In repressing the splicing of the c-src N1 exon, we find that PTB acts by a different mechanism. PTB does not interfere with U1 snRNP binding to the N1 5' splice site. Instead, PTB prevents formation of the prespliceosomal early (E) complex across the intervening intron by preventing the assembly of the splicing factor U2AF on the 3' splice site of exon 4. When the unregulated 5' splice site of the upstream exon 3 is present, U2AF binding is restored and splicing between exons 3 and 4 proceeds in spite of the N1 exon bound PTB. Thus, rather than directly blocking the N1 splice sites, PTB prevents the 5' splice site-dependent assembly of U2AF into the E complex. This mechanism likely occurs in many other alternative exons.     

Arsenic removal from the aqueous system using plant biomass: a bioremedial approach

Metal species released into the environment by technological activities tend to persist indefinitely, circulating and eventually accumulating throughout the food chain, thus becoming a serious threat to the environment. Environment pollution by toxic metals occurs globally through military, industrial, and agricultural processes and waste disposal. Bioremediation processes are the target of recent research and are considered low-cost, ecofriendly methods to alleviate the current problems of water decontamination, particularly for remote and rural areas. The present piece of work reports the unexploited sorption properties of the powdered seed of the plant Moringa oleifera (SMOS) for the removal of Arsenic [As(III) and As(V)] from aqueous solutions. Sorption studies, using standard practices, result in the standardization of optimum conditions such as biomass dosages (2.0 g), metal concentrations (25 ppm), contact time (60 min) and volume of the test solutions (200 ml) at pH 7.5, for As(III) and pH 2.5 for As(V). Maximum sorption for As(III) and As(V) species is 60.21 and 85.6%, respectively. Protein/Amino acid-Arsenic interactions are found to play an important role in the biosorption process using plant biomass SMOS.