Cryopreservation and genetic stability assessment of regenerants of the critically endangered medicinal plant Dioscorea deltoidea Wall. ex Griseb. for cryobanking of germplasm

In Vitro Cellular & Developmental Biology - Plant - Dioscorea deltoidea Wall. ex Griseb. is a critically endangered, commercially important crop of high medicinal value. Several accessions of...     

Oxidative stress and its biomarkers in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease whose etiology remains largely unknown. The uncontrolled oxidative stress in SLE contributes to functional oxidative modifications of cellular protein, lipid and DNA and consequences of oxidative modification play a crucial role in immunomodulation and trigger autoimmunity. Measurements of oxidative modified protein, lipid and DNA in biological samples from SLE patients may assist in the elucidation of the pathophysiological mechanisms of the oxidative stress-related damage, the prediction of disease prognosis and the selection of adequate treatment in the early stage of disease. Application of these biomarkers in disease may indicate the early effectiveness of the therapy. This review is intended to provide an overview of various reactive oxygen species (ROS) formed during the state of disease and their biomarkers linking with disease. The first part of the review presents biochemistry and pathophysiology of ROS and antioxidant system in disease. The second part of the review discusses the recent development of oxidative stress biomarkers that relates pathogenesis in SLE patients and animal model. Finally, this review also describes the reported clinical trials of antioxidant in the disease that have evaluated the efficacy of antioxidant in the management of disease with ongoing conventional therapy.     

Role of PPE18 Protein in Intracellular Survival and Pathogenicity of Mycobacterium tuberculosis in Mice

Background

Ever since its discovery the mycobacterial proline-proline-glutamic acid (PPE) family of proteins has generated a huge amount of interest. Understanding the role of these proteins in the pathogenesis of Mycobacterium tuberculosis (Mtb) is important. We have demonstrated earlier that the PPE18 protein of Mtb induces IL-10 production in macrophages with subsequent downregulation of pro-inflammatory cytokines like IL-12 and TNF-α and favors a T-helper (Th) 2-type of immune response.

Methodology/Principal Findings

Using a ppe18 genetic knock-out Mtb strain, we have now carried out infection studies in mice to understand the role of PPE18 in Mtb virulence. The studies reveal that lack of PPE18 leads to attenuation of Mtb in vivo. Mice infected with the ppe18 deleted strain have reduced infection burden in lung, liver and spleen and have better survival rates compared to mice infected with the wild-type Mtb strain.

Conclusions/Significance

Taken together our data suggest that PPE18 could be a crucial virulence factor for intracellular survival of Mtb.     

The PE/PPE multigene family codes for virulence factors and is a possible source of mycobacterial antigenic variation: perhaps more?

The PE/PPE multigene family codes for approximately 10% of the Mycobacterium tuberculosis proteome and is encoded by 176 open reading frames. These proteins possess, and have been named after, the conserved proline-glutamate (PE) or proline-proline-glutamate (PPE) motifs at their N-terminus. Their genes have a conserved structure and repeat motifs that could be a potential source of antigenic variation in M. tuberculosis. PE/PPE genes are scattered throughout the genome and PE/PPE pairs are usually encoded in bicistronic operons although this is not universally so. This gene family has evolved by specific gene duplication events. PE/PPE proteins are either secreted or localized to the cell surface. Several are thought to be virulence factors, which participate in evasion of the host immune response. This review summarizes the current knowledge about the gene family in order to better understand its biological function.     

Antibacterial hydrogels of amino acid-based cationic amphiphiles

Development of biomaterials, which are inherently antibacterial having broad-spectrum activity against both Gram-positive and Gram-negative bacteria with considerable biocompatibility, is of tremendous importance in biomedicinal chemistry. Microbial infections are still of great concern, often originated from indwelling medical devices typically in hospitalized patients. To this end, hydrogelating soft materials particularly from low-molecular-weight (LMW) gelators have generated significant interest in preparing and modifying biomedicinal implants. Herein, we have developed L-tryptophan based cationic amphiphilic hydrogelators with varying degree of hydrophobicity that exhibited remarkable bactericidal activity against wide range of Gram-positive (MIC = 0.1-75 microg/mL) and Gram-negative bacteria (MIC = 0.5-5 microg/mL). Antimicrobial efficacy of the amphiphiles was greatly influenced by their alkyl chain length. This bactericidal effect of cationic hydrogelators is quite comparable or in some cases markedly better than that of clinically available antibiotics. Most excitingly, they selectively attack the bacterial pathogens while remain biocompatible to the mammalian cells. Thus, we have developed LMW biocompatible, inherently antibacterial hydrogels having potential applications in biomedicines.     

Structural variations in species B adenovirus fibers impact CD46 association

A majority of species B adenoviruses (Ads) use CD46 as their primary receptor; however, the precise mechanisms involved in the binding of different Ad types to CD46 have not been resolved. Although previous studies indicate close similarities between two members of species B2 Ads in their usage of CD46, our current investigations revealed a surprisingly low CD46 binding affinity of the species B1 Ad16 fiber knob (equilibrium dissociation constant of 437 nM). We determined the crystal structure of the Ad16 fiber knob and constructed a model of this protein in complex with CD46. A comparison of this model to that of the CD46-Ad11 complex revealed structural differences in the FG and IJ loops that are part of the CD46 binding site. An analysis of a panel of recombinant fiber knobs with mutations targeting these regions in Ad16 and Ad11 uncovered a major contribution of the FG loop on CD46 binding. Two extra residues in the FG loop of the Ad16 fiber significantly reduce receptor interaction. Although avidity effects permit the use of CD46 on host cells by Ad16, virus binding occurs with lower efficiency than with B2 Ad types. The longer FG loop of the Ad16 fiber knob also is shared by other species B1 Ad fibers and, thus, may contribute to the low CD46 binding efficiencies observed for these Ad types. Our findings provide a better understanding of how different Ad types associate with CD46 and could aid in the selection of specific Ad fibers for more efficient Ad gene delivery vectors.     

Functional analysis of the essential GTP-binding-protein-coding gene cgtA of Vibrio cholerae

The cgtA gene, coding for the conserved G protein CgtA, is essential in bacteria. In contrast to a previous report, here we show by using genetic analysis that cgtA is essential in Vibrio cholerae even in a Delta relA background. Depletion of CgtA affected the growth of V. cholerae and rendered the cells highly sensitive to the replication inhibitor hydroxyurea. Overexpression of V. cholerae CgtA caused distinct elongation of Escherichia coli cells. Deletion analysis indicated that the C-terminal end of CgtA plays a critical role in its proper function.     

Management of <Emphasis Type="Italic">Sclerotium rolfsii</Emphasis> with integration of non-conventional chemicals,vermicompost and <Emphasis Type="Italic">Pseudomonas syringae</Emphasis>

Two non-conventional chemicals, ZnSO₄ (10⁻⁴ mM) and oxalic acid (4 mM) were tested (alone as well as in combination with seeds bacterized with Pseudomonas syringae strain PUR46 and vermicompost substitution in the potting soil), for their ability to suppress collar rot of chickpea (Cicer arietinum) caused by Sclerotium rolfsii under greenhouse conditions. ZnSO₄ and oxalic acid were applied as pre-inoculation foliar spray on chickpea and subsequently challenged with S. rolfsii. Both the chemicals provided significant protection to chickpea compared to control (100% plant mortality) when used alone as well as in combination with PUR46 and vermicompost. However, ZnSO₄ was more effective than oxalic acid against S. rolfsii. Amongst the treatments tried, plant mortality was least when ZnSO₄ was used in combination with seed bacterization with PUR46 and 25% vermicompost substitution. The findings indicate the utility of integration of the above factors in managing collar rot efficiently.     

Arabidopsis thaliana and Thlaspi caerulescens respond comparably to low zinc supply

The main objective of this research was to study the response of Arabidopsis thaliana L. and Thlaspi caerulescens J. & C. Presl to different Zn supplies. The A. thaliana plants were exposed to Zn-deficiency (0 and 0.05 μM Zn) and compared to the plants grown on media containing standard Zn (2 μM). T. caerulescens plants were also exposed to Zn-deficiency (0.05 μM Zn), but as this is a Zn hyperaccumulator species, also to high Zn (1,000 μM Zn). Plants were compared to plants grown on standard Zn media (100 μM Zn). Both A. thaliana and T. caerulescens were found to be heavily affected by Zn deficiency, showing similar retarded growth and reduced reproduction phenotypes, and even less reduction in biomass production in T. caerulescens than in A. thaliana. T. caerulescens plants were similarly affected when grown on high Zn concentrations, with comparable effects on reproductive tissues as seen on low Zn supply.