The ARF-like GTPases Arl1p and Arl3p act in a pathway that interacts with vesicle-tethering factors at the Golgi apparatus

The ARLs are a diverse family of GTPases that are related to ADP-ribosylation factors (ARFs), but whose function is poorly understood. There are at least ten ARLs in humans, two of which have homologs in the yeast Saccharomyces cerevisiae (ARL1/Arl1p and ARFRP1/Arl3p). The function of ARFRP1 is unknown, but mammalian ARL1 has recently been found to interact with a number of effectors including the GRIP domain that is present in a family of Golgi-localized long coiled-coil proteins. We find that in yeast, the intracellular targeting of Imh1p, the only yeast GRIP domain protein, is dependent on both Arl1p and Arl3p, but not on the ARF proteins. A recombinant form of the Imh1p GRIP domain binds to Arl1p in a GTP-dependent manner, but not to Arl3p. Yeast also contain a relative of SCOCO, a protein proposed to bind human ARL1, but this yeast protein, Slo1p, appears to bind Arl3p rather than Arl1p in vitro. However, Imh1p is not the sole effector of Arl1p since affinity chromatography of cytosol with immobilized Arl1p:GTP revealed an interaction with the GARP/VFT complex that is thought to act in the tethering of vesicles to the Golgi apparatus. Finally, we find that Arl3p is required in vivo for the targeting of Arl1p, explaining its requirement for the normal distribution of Imh1p.     

Adhesion molecule expression and infiltrating maternal leucocyte phenotypes during blastocyst implantation in the pig

During the implantation period (days 14 to 30 post coitum) in Large White pigs substantial numbers of endometrial sub-epithelial leucocytes were observed from about day 18 p.c. These were predominantly MHC Class II⁺, CD45⁺ and reactive for an accessory cell determinant carried by polymorphs and macrophages. Maternal lymphocytes of the CD2⁺, CD4^?, CD8^?, and a γδTcR⁺ subtype identified by the mAb 86D, were also present. Few CD4⁺, CD8⁺, or double-positive lymphocytes were seen. CD2^?CD4^?CD8^? γδTcR⁺ "Null" cells were seen in stroma adjacent to endometrial glands, as were CD2⁺ lymphocytes. There was no apparent upregulation of CD18, VLA-4 or CD25. E-selectin could not be detected on endothelium within uterine tissues or on trophectoderm, nor was a ligand for L-selectin detectable. The luminal aspect of the uterine epithelium was strongly reactive with anti-CD15 mAb, which was specifically blocked by lacto-N-fucopentaose III, indicating the presence of the Lewis^X determinant.     

An enzyme-p.m.r.-spectroscopic determination of the enantiomers of galactose

The action of d-galactose oxidase on d-galactose in the presence of oxygen afforded meso-galacto-hexodialdose quantitatively, which allowed p.m.r.-spectroscopic determination of the d enantiomer in a dl mixture. In the spectrum of the products obtained from the enzymic treatment of a mixture of d- and l-galactose, the magnitude of the aldehydrol signals derived solely from the oxidised d enantiomer, relative to those of the anomeric signals, provided the fractional content of the d enantiomer. This simple, accurate, and convenient procedure was applied to the hydrolysate of a seaweed galactan, which was also analyzed, for comparative purposes, by the fermentation technique employing d-galactose-adapted Saccharomyces cerevisiae.     

Indigenous Sediment Microbial Activity in Response to Nutrient Enrichment and Plant Growth Following a Controlled Oil Spill on a Freshwater Wetland

The population density and activity of a microbial community associated with the sediment and rhizosphere of an intertidal freshwater wetland dominated by Scirpus pungens was monitored before and following the application of weathered Mesa light crude oil and fertilizers. The influence of nutrient enrichment (fertilizers) and plant growth on oil degradation rates was determined from the resulting data. The study plots (four blocks of replicates) were subjected to five treatments: oil only (natural attenuation); oil plus ammonium nitrate and phosphate, with regular cropping of the plants; oil plus ammonium nitrate and phosphate; oil plus sodium nitrate and phosphate; no oil, ammonium nitrate and phosphate. The plots were regularly monitored in the field for gas production (carbon dioxide and nitrous oxide), and samples were collected for laboratory analysis of denitrification activity, aliphatic and aromatic hydrocarbon degradation activity, and total heteroptrophic bacteria. The viable bacterial population density increased during the first 4 weeks in oiled and unoiled experimental plots that were fertilized. In contrast, population densities in untreated areas remained relatively unchanged throughout the monitoring period. The microbial population demonstrated a rapid and sustained increase in naphthalene mineralization activity in plots that were both fertilized and oiled. Hexadecane mineralization activity increased in response to fertilizer application, with ammonium nitrate causing a larger increase than sodium nitrate. A very significant difference observed in the mineralization of hexadecane was that the surface sediments were much more active than the subsurface sediments. This difference became even more pronounced in the second year of monitoring, even though the treatment regime had been discontinued. This compartmentalization of mineralization activity was not observed for naphthalene. Following fertilizer application, field and laboratory evaluation of nitrogen metabolism in the sediments indicated significant denitrification activity that was not adversely affected by oiling. The results demonstrated that the application of fertilizers stimulated the activities of indigenous hydrocarbon-degrading and denitrifying bacteria, and the presence of oil either enhanced or had no detrimental effect on these activities. As a remediation strategy, the application of fertilizers to a wetland shoreline following an oil spill would promote the growth of indigenous plants and their associated microbial flora, resulting in increased metabolic activity and the potential for increased oil degradation activity.     

Xenobiotic metabolism in the human lung

The metabolism of xenobiotics by human lung has been investigated in tissue obtained from 10 patients undergoing pneumonectomy and compared with human liver activities in 6 different subjects. Lung microsomal fractions contain no detectable cytochrome P-450 while cytochrome b₅ values were 25% of those for human liver. NADH and NADPH-cytochrome c reductase activity are in the range of those reported for other species. Human lung microsomes possess < 3% of the metabolic activity of liver for the oxidation of benzpyrene, phenacetin and 7-ethoxycoumarin.     

Mechanisms of subzero growth in the cryophile Planococcus halocryophilus determined through proteomic analysis

The eurypsychrophilic bacterium Planococcus halocryophilus is capable of growth down to ?15°C, making it ideal for studying adaptations to subzero growth. To increase our understanding of the mechanisms and pathways important for subzero growth, we performed proteomics on P. halocryophilus grown at 23°C, 23°C with 12% w/v NaCl and ?10°C with 12% w/v NaCl. Many proteins with increased abundances at ?10°C versus 23°C also increased at 23C‐salt versus 23°C, indicating a closely tied relationship between salt and cold stress adaptation. Processes which displayed the largest changes in protein abundance were peptidoglycan and fatty acid (FA) synthesis, translation processes, methylglyoxal metabolism, DNA repair and recombination, and protein and nucleotide turnover. We identified intriguing targets for further research at ?10°C, including PlsX and KASII (FA metabolism), DD‐transpeptidase and MurB (peptidoglycan synthesis), glyoxalase family proteins (reactive electrophile response) and ribosome modifying enzymes (translation turnover). PemK/MazF may have a crucial role in translational reprogramming under cold conditions. At ?10°C P. halocryophilus induces stress responses, uses resources efficiently, and carefully controls its growth and metabolism to maximize subzero survival. The present study identifies several mechanisms involved in subzero growth and enhances our understanding of cold adaptation.