Proliferative T-cell response to HIV envelope glycoprotein in immunized and infected primates and human beings

Human immunodeficiency virus (HIV)-specific helper T-cell response was studied in human subjects and nonhuman primates either infected with HIV or immunized with different HIV protein preparations. A strong group-specific T-cell response involving T-cell proliferation and lymphokine secretion was observed in immunized chimpanzees and rhesus monkeys as well as HIV-infected chimpanzees and gibbons. HIV-infected people demonstrated a low or no HIV-specific T-cell response. In contrast, five of 14 HIV antibody-negative sexual partners of HIV-infected men recognized one or more T-cell epitopes in the envelope glycoprotein of HIV.     

Electron Microscopic Observations on Virus-Like Particles Associated with SH Antigen

The structural aspects of SH antigen-containing particles were investigated. These studies confirmed the existence of a large spherical particle (ca. 43 nm) and smaller (ca. 20 nm) rod- and sphere-shaped particles. The large particle consists of an outer and inner membrane and a core of "nucleic acid" as seen by positive staining techniques. The outer membrane of the large particle appears to be similar to that of the 20-nm diameter spheres and rods known to possess the SH antigen.     

Elaboration of leukocyte migration inhibitory factor by human lymphocyte subpopulations stimulated with mitogens.

This paper describes experiments to determine whether human lymphocyte sub-populations stimulated with a variety of mitogens, leucoagglutinin (LA), concanavalin A (con A), pokeweed mitogen (PWM), protein A (prot A), and anti-β₂-microglobulin (anti-β₂m), synthesize lymphokines. T and B lymphocytes as well as unseparated mononuclear cells were stimulated with the mitogens, and the presence of leukocyte inhibitory factor (LIF) in the culture supernatants was tested by an agarose migration method. Culture supernatants stimulated with LA or prot A were also fractionated on Sephadex G-100 columns, and LIF-containing fractions were tested for heat stability and the effect of monosaccharides. The results indicated that LA and con A caused LIF synthesis only in T-cell populations, while PWM stimulated both T and B lymphocytes and prot A and anti-β₂mm were B-cell stimulants. Furthermore, LIF from LA-and prot-A-stimulated cultures behaved similarly upon physicochemical characterization.     

Iodine deficiency activates antioxidant genes and causes DNA damage in the thyroid gland of rats and mice

Because thyroid nodules are frequent in areas with iodine deficiency the aim of this study was to characterise molecular events during iodine deficiency that could explain mutagenesis and nodule formation. We therefore studied gene expression of catalytic enzymes prominent for H(2)O(2) detoxification and antioxidative defence, quantified DNA oxidation and damage as well as spontaneous mutation rates (SMR) in mice and rats fed an iodine controlled diet. Antioxidative enzymes such as superoxide dismutase 3, glutathione peroxidase 4 and the peroxiredoxins 3 and 5 showed increased mRNA expression, which indicates increased radical burden that could be the cause of additional oxidized base adducts found in thyroidal genomic DNA in our experiments of iodine deficiency. Furthermore, the uracil content of thyroid DNA was significantly higher in the iodine-deficient compared to the control group. While SMR is very high in the normal thyroid gland it is not changed in experimental iodine deficiency. Our data suggest that iodine restriction causes oxidative stress and DNA modifications. A higher uracil content of the thyroid DNA could be a precondition for C-->T transitions often detected as somatic mutations in nodular thyroid tissue. However, the absence of increased SMR would argue for more efficient DNA repair in response to iodine restriction.     

Massarilactones E-G, new metabolites from the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima

Three new massarilactones E-G (1-3) and the massarilactone acetonide (4) were isolated from the ethyl acetate extract of the endophytic fungus Coniothyrium sp., associated with the plant Artimisia maritima. Their structures were determined by analysis of the 1D and 2D NMR and mass spectroscopic data. The structure of massarilactones E (1) was confirmed by X-ray diffraction analysis, and its absolute configuration determined by the solid-state CD/TDDFT method.     

Structure of the O-polysaccharide of the lipopolysaccharide of Pseudomonas syringae pv. garcae ICMP 8047.

The composition and structure of the O-polysaccharide of the lipopolysaccharide of Pseudomonas syringae pathovar garcae ICMP 8047 were studied using methylation analyses, Smith degradation, and 1H- and 13C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), total correlation spectroscopy (TOCSY), nuclear Overhauser effect spectroscopy (NOESY), and H-detected 1H,13C heteronuclear multiple-quantum coherence (HMQC) experiments. The polysaccharide was found to contain L-rhamnose and 3-acetamido-3, 6-dideoxy-D-galactose (D-Fuc3NAc) in the ratio 4:1 and to consist of two types of pentasaccharide repeating units. The major (1) and minor (2) repeating units differ from each other only in the position of substitution of one of the rhamnose residues in the main chain. Similar structural heterogeneity has been reported formerly in O-polysaccharides of some other P. syringae strains having a similar monosaccharide composition. A Fuc3NAc residue is attached to the main rhamnan chain as a side chain by a (alpha1-->4) glycosidic linkage; this has not hitherto been described in P. syringae: [figure].