Mucosal epithelial cells and Langerhans cells are targets for infection by the immunosuppressive type D retrovirus simian AIDS retrovirus serotype 1

Simian acquired immune deficiency syndrome (SAIDS) caused by the type D retrovirus SRV-1 results in opportunistic infections and a spectrum of oral lesions similar to those seen in humans with AIDS. To better understand the pathogenesis of these oral lesions we have retrospectively examined the oral mucosa from ten rhesus monkeys that died with SAIDS and prospectively examined the oral mucosa of ten additional animals inoculated with SRV-1 to determine at what time, and in what cells SRV-1 infection of the oral mucosa occurs. Using single and double label immunohistologic techniques, and electron microscopy we detected SRV-1 in clusters of oral epithelial cells and rare Langerhans cells as early as 1 month postinoculation.     

Isoforms of apolipoprotein A-II in human plasma and thoracic duct lymph. Identification of proapolipoprotein A-II and sialic acid-containing isoforms

Proapolipoprotein (apo-) A-II and several isoforms of apo-A-II including sialylated isoforms were identified in human plasma and thoracic duct lymph. Proapo-A-II secreted by HepG2 cells was identified by a combination of immunoblots and [14C]arginine incorporation. Proapo-A-II which contains 2 arginine residues could be readily differentiated from mature apo-A-II which contains no arginine. The pI of proapo-A-II is 6.79, whereas the pI of the major apo-A-II isoform in plasma and lymph is 4.90. Minor apo-A-II isoforms have pI values of 5.17, 4.68, 4.42, and 4.20, respectively. Sialoisoforms of apo-A-II were identified, which had a higher apparent molecular weight on sodium dodecyl sulfate-gel electrophoresis than the major isoform and disappeared following neuraminidase treatment. The relative quantity of proapo-A-II was relatively constant in lymph very low density lipoproteins, lymph high density lipoproteins, and plasma high density lipoproteins, whereas the sialoforms and the other minor isoforms of apo-A-II were greater in lymph very low density lipoproteins and the lowest in plasma high density lipoproteins.     

The human apolipoprotein A-II gene is located on chromosome 1

Apolipoprotein (apo) A-II is a major constituent of high density lipoproteins (HDL). The gene for apoA-II has been localized to the p21----qter region of chromosome 1 in man by Southern blot hybridization analysis of DNA from human-mouse cell hybrids using a cloned human apoA-II cDNA probe. The regional assignment was established using two hybrids carrying a reciprocal translocation involving chromosomes 1 and 2. Comparison with previously established gene loci on chromosomes 1 suggests that apoA-II may reside in a conserved linkage group with renin and peptidase C. On the other hand, apoA-II is not linked to the apoA-I gene, which has been localized previously to chromosome 11.     

Relationship of the env genes and the endonuclease domain of the pol genes of simian foamy virus type 1 and human foamy virus.

We have molecularly cloned and sequenced a portion of the simian foamy virus type 1 (SFV-1); open reading frames representing the endonuclease domain of the polymerase (pol) and the envelope (env) genes were identified by comparison with the human foamy virus (HFV). Unlike the HFV genomic organization, the SFV-1 pol gene overlaps the env gene; thus, the open reading frames reported for HFV between pol and env is not present in SFV-1. Comparisons of predicted amino acid sequences of HFV and SFV-1 reveal that the endonuclease domains of the pol genes are about 84% related. The region predicted to encode the SFV-1 extracellular env domain is 569 codons; SFV-1 and HFV have 64% amino acid similarity in this env domain. The predicted hydrophobic transmembrane env proteins of both HFV and SFV-1 show about 73% similarity. A total of 16 potential glycosylation sites are found in SFV-1 env, and 15 are found in HFV; 11 are shared. SFV-1 has 25 cysteine residues, and HFV has 23 residues; all 23 cysteine residues of HFV are conserved in SFV-1. This sequence analysis reveals that the human and simian foamy viruses are highly related.     

Genital mucosal transmission of simian immunodeficiency virus: animal model for heterosexual transmission of human immunodeficiency virus.

An animal model for the heterosexual transmission of human immunodeficiency virus (HIV) was developed by the application of simian immunodeficiency virus (SIV) onto the genital mucosas of both mature and immature, male and female rhesus macaques. Virus preparations were infused into the vaginal vaults or the urethras (males) of the animals through a soft plastic pediatric nasogastric feeding tube. The macaques that were infected by this route (six males and nine females) developed SIV-specific antibodies, and SIV was isolated from peripheral mononuclear cells of all seropositive animals. One male and one female infected by this route developed severe acquired immunodeficiency syndrome-like disease with retroviral giant-cell pneumonia. As few as two inoculations of cell-free SIV containing 50 50% tissue culture infective doses induced persistent viremia. Cell-free virus preparations were capable of producing infection by the genital route. Much higher doses of virus were required to transmit SIV by this route than are required for transmission by intravenous inoculation. Thus, it appears that the mucous membranes of the genital tract act as a barrier to SIV infection. Spermatozoa and seminal plasma were not required for the genital transmission of SIV. Rarely, SIV was recovered from mononuclear cells in semen and vaginal secretions. The SIV-rhesus macaque model is suitable for assessing the role of cofactors in heterosexual transmission of HIV and will be useful for testing the effectiveness of spermicides, pharmacologic agents, and vaccines in preventing the heterosexual transmission of HIV.     

Evidence for the Existence of Differential O-Glycosylated α5-Subunits of the γ-Aminobutyric AcidA Receptor in the Rat Brain

Abstract: Polyclonal antibodies were raised to synthetic peptides having amino acid sequences corresponding with the N- or C-terminal part of the γ-aminobutyric acid_A (GABA_A) receptor α₅-subunit. These anti-peptide α₅(2–10) or anti-peptide α₅(427–433) antibodies reacted specifically with GABA_A receptors purified from the brains of 5–10-day-old rats in an enzyme-linked immunosorbent assay and were able to dose-dependently immunoprecipitate up to 6.3 or 13.1% of the GABA_A receptors present in the incubation, respectively. In immunoblots, each of these antibodies reacted with the same two protein bands with apparent molecular mass of 53 or 57 kDa. After exhaustive treatment of purified GABA_A receptors with N -Glycanase, each of these antibodies identified two proteins with apparent molecular masses of 46 and 48 kDa. Additional treatment of GABA_A receptors with neuraminidase and O -Glycanase resulted in an apparently single protein with molecular mass of 47 kDa, which again was identified by both the anti-peptide α₅(2–10) and the anti-peptide α₅(427–433) antibody. These results indicate the existence of at least two different α₅-sub-units of the GABA_A receptor that differ in their carbohydrate content. In contrast to other α- or β-subunits of GABA_A receptors so far investigated, at least one of these two α₅-subunits contains O-linked carbohydrates.     

The unexpected long period of elevated CH4 emissions from an inundated fen meadow ended only with the occurrence of cattail (Typha latifolia)

Drainage and agricultural use transform natural peatlands from a net carbon (C) sink to a net C source. Rewetting of peatlands, despite of high methane (CH₄) emissions, holds the potential to mitigate climate change by greatly reducing CO₂ emissions. However, the time span for this transition is unknown because most studies are limited to a few years. Especially, nonpermanent open water areas often created after rewetting, are highly productive. Here, we present 14 consecutive years of CH₄ flux measurements following rewetting of a formerly long-term drained peatland in the Peene valley. Measurements were made at two rewetted sites (non-inundated vs. inundated) using manual chambers. During the study period, significant differences in measured CH₄ emissions occurred. In general, these differences overlapped with stages of ecosystem transition from a cultivated grassland to a polytrophic lake dominated by emergent helophytes, but could also be additionally explained by other variables. This transition started with a rapid vegetation shift from dying cultivated grasses to open water floating and submerged hydrophytes and significantly increased CH₄ emissions. Since 2008, helophytes have gradually spread from the shoreline into the open water area, especially in drier years. This process was periodically delayed by exceptional inundation and eventually resulted in the inundated site being covered by emergent helophytes. While the period between 2009 and 2015 showed exceptionally high CH₄ emissions, these decreased significantly after cattail and other emergent helophytes became dominant at the inundated site. Therefore, CH₄ emissions declined only after 10 years of transition following rewetting, potentially reaching a new steady state. Overall, this study highlights the importance of an integrative approach to understand the shallow lakes CH₄ biogeochemistry, encompassing the entire area with its mosaic of different vegetation forms. This should be ideally done through a study design including proper measurement site allocation as well as long-term measurements.     

Sex differences in heritability of BMI: a comparative study of results from twin studies in eight countries.

Body mass index (BMI), a simple anthropometric measure, is the most frequently used measure of adiposity and has been instrumental in documenting the worldwide increase in the prevalence of obesity witnessed during the last decades. Although this increase in overweight and obesity is thought to be mainly due to environmental changes, i.e., sedentary lifestyles and high caloric diets, consistent evidence from twin studies demonstrates high heritability and the importance of genetic differences for normal variation in BMI. We analysed self-reported data on BMI from approximately 37,000 complete twin pairs (including opposite sex pairs) aged 20-29 and 30-39 from eight different twin registries participating in the GenomEUtwin project. Quantitative genetic analyses were conducted and sex differences were explored. Variation in BMI was greater for women than for men, and in both sexes was primarily explained by additive genetic variance in all countries. Sex differences in the variance components were consistently significant. Results from analyses of opposite sex pairs also showed evidence of sex-specific genetic effects suggesting there may be some differences between men and women in the genetic factors that influence variation in BMI. These results encourage the continued search for genes of importance to the body composition and the development of obesity. Furthermore, they suggest that strategies to identify predisposing genes may benefit from taking into account potential sex specific effects.     

Early cytokine and chemokine gene expression in lymph nodes of macaques infected with simian immunodeficiency virus is predictive of disease outcome and vaccine efficacy.

Competitive PCR was used to evaluate the expression of cytokine, granzyme B, and chemokine genes in lymph nodes of macaques recently infected with the simian immunodeficiency virus (SIV) pathogenic molecular clone SIVmac239 (n = 16), the nonpathogenic vaccine strain SIVmac239 delta nef (n = 8), and the nonpathogenic molecular clone SIVmac1A11 (n = 8). For both SIVmac239 and its nef-deleted derivative, strong expression was observed as early as 7 days postinfection for interleukin 1beta (IL-1beta), IL-6, tumor necrosis factor alpha, gamma interferon, and IL-13. The levels of gene induction were equally intense for both viruses despite a lower viral load for SIVmac239 deltanef compared with that for SIVmac239. However, the nature of the cytokine network activation varied with the viral inocula. Primary infection with SIVmac239 was characterized by a higher level of IL-4, IL-10, MIP-1alpha, MIP-1beta, MCP-1, and RANTES gene expression and a lower level of IL-12 and granzyme B gene expression compared with infection with SIVmac239 delta nef. Thus, infection with nef-deleted SIV was associated with a preferential Th1 versus Th2 pattern of cytokine production. Infection with SIVmac1A11 was characterized by a delayed immune response for all markers tested. The unique patterns of cytokine and chemokine gene expression in lymph nodes correlated nicely with the pathogenic potential of the SIV strains used as well as with differences in their ability to serve as protective vaccines.     

Progress in fold recognition

The prediction experiment reveals that fold recognition has become a powerful tool in structural biology. We applied our fold recognition technique to 13 target sequences. In two cases, replication terminating protein and prosequence of subtilisin, the predicted structures are very similar to the experimentally determined folds. For the first time, in a public blind test, the unknown structures of proteins have been predicted ahead of experiment to an accuracy approaching molecular detail. In two other cases the approximate folds have been predicted correctly. According to the assessors there were 12 recognizable folds among the target proteins. In our postprediction analysis we find that in 7 cases our fold recognition technique is successful. In several of the remaining cases the predicted folds have interesting features in common with the experimental results. We present our procedure, discuss the results, and comment on several fundamental and technical problems encountered in fold recognition. © 1995 Wiley-Liss, Inc.