Sequestration of lichen compounds by three species of terrestrial snails.

Three species of lichen-grazing snails,Balea perversa, Chondria clienta, andHelicigona lapicida, all from the Swedish island of Öland, were found to sequester lichen compounds when feeding on the crustous lichen speciesAspicila calcarea, Caloplaca flavovirescens, Lecanora muralis, Physcia adscendens, Tephromela atra, andXanthoria parietina. The lichen compounds detected in the soft bodies of the snail species analyzed included the anthraquinone parietin, the depside atranorin, as well as a presumable degradation product of the latter. Other lichen compounds such as (+)-usnic acid or α-collatolic acid were not found in the soft bodies but were only detected in the feces, suggesting selective uptake of lichen compounds by the snails.

Complete DNA sequence of yeast chromosome II.

In the framework of the EU genome-sequencing programmes, the complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome II (807 188 bp) has been determined. At present, this is the largest eukaryotic chromosome entirely sequenced. A total of 410 open reading frames (ORFs) were identified, covering 72% of the sequence.

Herbivory on calcicolous lichens: different food preferences and growth rates in two co-existing land snails.

A total of 32 calcicolous lichen species, one alga and one bryophyte were recorded on a limestone wall in the grassland Great Alvar on the Baltic island of Öland, Sweden. Fourteen (41%) of these 34 species and free-living cyanobacteria showed herbivore damage, most probably due to grazing by the land snails Chondrina clienta and Balea perversa which inhabited the limestone wall. Three laboratory experiments were conducted to examine the food preferences of individuals of C.

HIV-1 Nef leads to inhibition or activation of T cells depending on its intracellular localization.

Nef of primate lentiviruses is required for viremia and progression to AIDS in monkeys. Negative, positive, and no effects of Nef have also been reported on viral replication in cells. To reconcile these observations, we expressed a hybrid CD8-Nef protein in Jurkat cells.

Human immunodeficiency virus type 1 Nef associates with a cellular serine kinase in T lymphocytes.

With T-cell lines constitutively expressing Nef from the SF2 strain of human immunodeficiency virus type 1 (HIV-1SF2) in the form of a hybrid CD8-Nef fusion protein or T-cell lines chronically infected with HIV-1SF2, a cellular serine kinase was found that specifically associates with Nef. Proteins of 62 kDa and 72 kDa, which coimmunoprecipitated with Nef, were phosphorylated in in vitro kinase assays. This Nef-associated serine kinase activity was not blocked by inhibitors of protein kinase C or protein kinase A and was lost when Nef was truncated at amino acid 94 or 99.

Effects of CD45 on NF-kappa B. Implications for replication of HIV-1.

Increased levels of replication of the HIV type 1 are observed after the activation of infected T cells through the TCR. However, anti-CD45 antibodies inhibit these effects in cells from infected individuals. In this study, we examined interrelationships between CD45 and HIV-1 further.

Second exon of Tat of HIV-2 is required for optimal trans-activation of HIV-1 and HIV-2 LTRs.

To determine conditions for optimal trans-activation by Tat of HIV-2, genomic DNAs and cDNAs encoding Tat of HIV-2 were tested on their homologous (HIV-2) and heterologous (HIV-1) long terminal repeats (LTRs). It has been previously reported that Tat of HIV-2 could efficiently trans-activate only its own LTR but not that of HIV-1. The inefficient trans-activation of HIV-1 is due, in part, to an acidic residue in the basic, RNA-binding domain of Tat of HIV-2.

Sequence and function analysis of a 4.3 kb fragment of Saccharomyces cerevisiae chromosome II including three open reading frames.

The nucleotide sequence of a fragment of 4337 base pairs of Saccharomyces cerevisiae chromosome II has been determined. The sequence contains three open reading frames, one of them being incomplete. Deletion analysis showed that YBR12.

Sequence of a 4.8 kb fragment of Saccharomyces cerevisiae chromosome II including three essential open reading frames.

The nucleotide sequence of a fragment of 4867 base pairs of Saccharomyces cerevisiae chromosome II has been determined. The sequence contains three complete open reading frames. In addition to the already known gene RPB5, coding for a subunit shared by all three DNA directed RNA polymerases, two new open reading frames could be identified.

CD45 mAb induces cell adhesion in peripheral blood mononuclear cells via lymphocyte function-associated antigen-1 (LFA-1) and intercellular cell adhesion molecule 1 (ICAM-1).

A novel cell aggregation-inducing characteristic of the leukocyte common antigen, CD45, is described and its underlying molecular mechanisms investigated. Formation of strong cell clusters was consistently observed in human PBMCs after crosslinking CD45 molecules with antibodies, directed to epitopes common for all CD45 isoforms (e.g.

[Primary Hodgkin disease of the lung].

We describe a patient with a rare primary pulmonary manifestation of Hodgkin's disease who presented with multiple bilateral nodular lesions on the chest x-ray without significant hilar involvement.

Synthesis of extracellular matrix components by human ciliary muscle cells in culture.

The production and spatial organization of connective tissue components in ciliary muscle cell cultures was studied with immunohistochemical and ultrastructural methods. Antibodies against collagen types IV and VI, fibronectin and laminin were used. Laminin stains as pericellular network surrounding individual muscle cells.

Recombinant antigens in viral diagnosis.

DNA-fragments coding for a variety of different viral antigens have been cloned and expressed in E. coli. Selected purified recombinant antigens were used for detection of specific antibodies by the means of ELISA technique.

Viral culture and p24 antigenemia of human immunodeficiency virus (HIV)-infected individuals correlated with antibody profiles determined with recombinant polypeptides of all HIV-1 open-reading frames.

The association between viral activity and antibody profiles was investigated in 202 individuals infected by the human immunodeficiency virus (HIV) grouped according to their Walter Reed clinical stage. Each study group was subdivided into subjects positive or negative for markers of active viral replication: presence of serum p24 antigen and viral culture. In Western blots using recombinant antigens, sera of HIV-positive individuals with positive viral markers had a significantly lower antibody reactivity to several viral proteins than did individuals without viral markers.

Antibodies against p24 of HIV-1 in patients with systemic lupus erythematosus?

The involvement of retroviruses in the etiopathogenesis of autoimmunity is discussed. Recently antibodies against p24 of HIV-1 were described in patients from Texas with SLE. Therefore we investigated the presence of these antibodies in our SLE collective (German caucasians and blacks from Michigan) employing ELISA and Western blot.

Recombinant antigens in viral diagnosis.

DNA fragments coding for a variety of different viral antigens have been cloned and expressed in Escherichia coli. Selected purified recombinant antigens were used for detection of specific antibodies by means of the ELISA technique. This approach has been used for the development of four different ELISAs for the detection of HIV- and EBV-specific antibodies.

Alpha-lipoic acid is an effective inhibitor of human immuno-deficiency virus (HIV-1) replication.

Alpha-lipoic acid, a naturally occurring disulfide-compound that acts as a cellular coenzyme, inhibits replication of HIV-1 in cultured lymphoid T-cells. Alpha-lipoic acid was added 16 hours after infection of the T-cell lines Jurkat, SupT1 and Molt-4 with HTLV IIIB and HIV-1 Wal (a wild type HIV-1 isolate). We observed a dose dependent inhibition of HIV-1-replication in CPE (Cytopathic effect) formation, reverse transcriptase activity and plaque formation on CD4-transformed HeLa-cells.

Cell cultures of human ciliary muscle: growth, ultrastructural and immunocytochemical characteristics.

Primary ciliary muscle cell cultures derived from human donors (16-91 years) were established and characterized by comparing them with ciliary muscle in tissue sections using immunocytochemical and ultrastructural methods. Monoclonal antibodies against desmin, vimentin, alpha-actinin, smooth muscle (sm) specific alpha-actin and von Willebrand factor were used. In tissue sections of the ciliary body, ciliary muscle cells, vascular muscle cells, pericytes, endothelial cells and fibroblasts stain for vimentin.

Expression of human immunodeficiency virus (HIV) in naturally infected peripheral blood mononuclear cells: comparison of a standard co-culture technique with a newly developed microculture method.

Peripheral blood mononuclear cells (PBMCs) from 29 patients infected with human immunodeficiency virus (HIV) were cultured by two different methods. One was the standard co-culture technique, the other a newly developed microculture method. In this assay 10(6) PBMCs were cultivated in 250 microliters medium, no activating agents or allogeneic cells were present.

[Historia morbi atrocis--2 new cases of spontaneous rupture of the esophagus (Boerhaave syndrome)].

We report the case of two patients hospitalized within a few weeks of each other and both presenting with spontaneous rupture of the esophagus whose evolution proved fatal. We take the opportunity of drawing attention to this rare and challenging disease, which is often diagnosed too late.

Antibody- and complement-mediated lysis of HIV-infected cells and inhibition of viral replication.

HIV-1-positive antisera were tested for their ability to lyse HIV-1-infected cells in the presence of active complement. Cytolytic effects caused by sera derived from infected humans were slower than those observed with sera from immunised chimpanzees. Lytic but also negative sera were found among HIV-1-infected asymptomatic men as well as among clinical AIDS cases.