Generation and Characterization of a Bivalent HIV-1 Subtype C gp120 Protein Boost for Proof-of-Concept HIV Vaccine Efficacy Trials in Southern Africa.

The viral envelope glycoprotein (Env) is the major target for antibody (Ab)-mediated vaccine development against the Human Immunodeficiency Virus type 1 (HIV-1). Although several recombinant Env antigens have been evaluated in clinical trials, only the surface glycoprotein, gp120, (from HIV-1 subtype B, MN, and subtype CRF_01AE, A244) used in the ALVAC prime-AIDSVAX gp120 boost RV144 Phase III HIV vaccine trial was shown to contribute to protective efficacy, although modest and short-lived. Hence, for clinical trials in southern Africa, a bivalent protein boost of HIV-1 subtype C gp120 antigens composed of two complementary gp120s, from the TV1.

Trimeric HIV Env provides epitope occlusion mediated by hypervariable loops.

Hypervariable loops of HIV-1 Env protein gp120 are speculated to play roles in the conformational transition of Env to the receptor binding-induced metastable state. Structural analysis of full-length Env-based immunogens, containing the entire V2 loop, displayed tighter association between gp120 subunits, resulting in a smaller trimeric diameter than constructs lacking V2. A prominent basal quaternary location of V2 and V3' that challenges previous reports would facilitate gp41-independent gp120-gp120 interactions and suggests a quaternary mechanism of epitope occlusion facilitated by hypervariable loops.

Modulation of Bacillus thuringiensis phosphatidylinositol-specific phospholipase C activity by mutations in the putative dimerization interface.

Cleavage of phosphatidylinositol (PI) to inositol 1,2-(cyclic)-phosphate (cIP) and cIP hydrolysis to inositol 1-phosphate by Bacillus thuringiensis phosphatidylinositol-specific phospholipase C are activated by the enzyme binding to phosphatidylcholine (PC) surfaces. Part of this reflects improved binding of the protein to interfaces. However, crystallographic analysis of an interfacially impaired phosphatidylinositol-specific phospholipase (W47A/W242A) suggested protein dimerization might occur on the membrane.

Moloney murine leukemia virus decay mediated by retroviral reverse transcriptase degradation of genomic RNA.

Retroviral vectors are powerful tools for the introduction of transgenes into mammalian cells and for long-term gene expression. However, their application is often limited by a rapid loss of bioactivity: retroviruses spontaneously loose activity at 37 degrees C, with a half-life of 4 to 9 h depending on the retrovirus type. We sought to determine which components of the retrovirus are responsible for this loss in bioactivity and to obtain a quantitative characterization of their stability.

Site-directed mutagenesis of the hinge peptide from the hemagglutinin protein: enhancement of the pH-responsive conformational change.

Environmentally responsive proteins and peptides are increasingly finding utility in various engineered systems due to their ability to respond to the presentation of external stimuli. A classic example of this behavior is the influenza hemagglutinin (HA) fusion protein. At neutral pH, HA exists in a non-fusogenic state, but upon exposure to low pH, the conformation of the structure changes to expose a fusogenic peptide.

Antifungal activity of lactobacilli isolated from salami.

Sixty-five strains of lactobacilli isolated from salami were tested for their antifungal activity in early and late phases of growth. Ten strains showed inhibitory activity in the early phase of growth towards moulds such as Aspergillus and Penicillium. The active compounds identified were phenyl-lactate and hydroxy-phenyl-lactate.

Dimer structure of an interfacially impaired phosphatidylinositol-specific phospholipase C.

The crystal structure of the W47A/W242A mutant of phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus thuringiensis has been solved to 1.8A resolution. The W47A/W242A mutant is an interfacially challenged enzyme, and it has been proposed that one or both tryptophan side chains serve as membrane interfacial anchors (Feng, J.

Characterization of flocculent Saccharomyces interspecific hybrids for the production of sparkling wines.

Interspecific hybrids obtained from flocculent Saccharomyces cerevisiae and non-flocculent Saccharomyces uvarum (S. bayanus var. uvarum) are flocculent to a higher degree and have the capacity to ferment well at both low and high temperatures, from 6 to 36 degrees C.

Saccharomyces sensu stricto: systematics, genetic diversity and evolution.

Saccharomyces sensu stricto is a species complex that includes most of the yeast strains relevant in the fermentation industry as well as in basic science. The taxonomy of these yeasts has always been controversial, particularly at species level. Over the years, the grouping of Saccharomyces sensu stricto yeasts has undergone changes in accordance with the system employed in classifying yeast cultures.

Mutagenesis of putative catalytic and regulatory residues of Streptomyces chromofuscus phospholipase D differentially modifies phosphatase and phosphodiesterase activities.

Phospholipase D from Streptomyces chromofuscus (sc-PLD) is a member of the diverse family of metallo-phosphodiesterase/phosphatase enzymes that also includes purple acid phosphatases, protein phosphatases, and nucleotide phosphodiesterases. Whereas iron is an essential cofactor for scPLD activity, Mn2+ is also found in the enzyme. A third metal ion, Ca2+, has been shown to enhance scPLD catalytic activity although it is not an essential cofactor.

An iron-dependent bacterial phospholipase D reminiscent of purple acid phosphatases.

Recombinant phospholipase D (PLD) from Streptomyces chromofuscus (scPLD) has been characterized using colorimetric assays, spectroscopic investigations, and site-directed mutagenesis. scPLD, which shows phosphodiesterase activity toward a wide variety of phospholipids and phosphatase activity toward p-nitrophenyl phosphate, exhibits a visible absorption band with lambda(max) at 570 nm. Metal ion analysis performed by inductively coupled plasma mass spectroscopy shows the presence of approximately 1 equivalent of iron, 0.