Banding patterns of the chromosomes ofCercopithecus neglectus: Comparison withMiopithecus talapoin andErythrocebus patas

The G, Q, and C bands and the location of the nucleolar organizing regions (NORs) of the chromosomes of two male Cercopithecus neglectusare described. The diploid number of the species is 2n =62. Comparison with the karyotypes of Miopithecus talapoin (2n =54), and Erythrocebus patas (2n =54)showed the presence of total banding homeology for only 10 chromosome pairs.     

Effect of papulacandin B on β-glucan synthesis in Schizosaccharomyces pombe

Abstract The antifungal antibiotic papulacandin β inhibited B(1,3)glucan-synthase activity, in vitro, from Schizosaccharomyces pombe . Levels of β(1,3)glucan-synthase from antibiotic-treated cultures were lower than the control cultures whereas mannan-synthase and β(1,3)glucanase activities were almost unaffected. The presence of an osmotic stabilizer reduced the inhibition of growth caused by the antibiotic. Addition of papulacandin β to a culture of S. pombe specifically inhibited incorporation of glucose into the β-glucan cell wall fraction. The fatty acids as well as the hydroxyl groups on the phenol residue of the papulacandin β molecule were essential for the inhibitory activity.     

Mutants of Saccharomyces cerevisiae cell division cycle defective in cytokinesis. Biosynthesis of the cell wall and morphology

The four temperature-sensitive mutants of Saccharomyces cerevisiae in the cell division cycle defective in cytokinesis (cdc, 3, 10, 11 and 12), have been analyzed with respect to the biosynthesis of the cell wall polymers. After 3 hours of incubation at the non-permissive temperature (37°C) these strains stop growing. The synthesis of glucan, mannan and chitin (wall polymers) level off in a similar time, but glucan, mannan and chitin synthases remained active for at least 4 hours.If the mutants are analyzed by transmission and scanning electron microscopy different pictures emerge. Two of the mutants cdc 10 and cdc 12, after 3 hours of incubation at 37°C present apparently normal cytoplasms and cell wall surfaces with multiple elongated buds. The other two mutants, cdc 3 and cdc 11, present a completely disarranged cytoplasmic content and damage at the level of the plasma membrane is evident.These and other observations, suggest that between the execution points of cdc 3 (0.27) and cdc 10 (0.58), essential processes in the assembly of cell membrane occur.This work was supported in part by a grant from la Comisión de Investigación Científica y Técnica of the Spanish Ministerio de Educación y Ciencia (Project no. 4593-1980).     

The granin (chromogranin/secretogranin) family

The chromogranins/secretogranins, referred to in abbreviated form as granins, are a family of acidic secretory proteins that are found in the secretory granules of a wide variety of endocrine cells and neurons, being stored together with many different peptide hormones and neuropeptides. The recent elucidation of their primary structure has provided insights into possible functions of these proteins. Moreover, the granins have been successfully used as markers for normal and neoplastic endocrine and neuronal cells, as well as model proteins to understand the sorting mechanism involved in the formation of secretory granules.     

Approach to the analysis of diuretics and masking agents by high-performance liquid chromatography—mass spectrometry in doping control

The application of thermospray and plasmaspray high-performance liquid chromatography—mass spectrometry to the analysis of diuretics and probenecid has been investigated. The latter method gave better ionization efficiency than the former, and its response was optimized by altering the solvent composition: best results were obtained with water—methanol—acetonitrile—trifluoroacetic acid. Using different proportions of these solvents, three isocratic systems were developed to separate the compounds under study. The principal characteristic of plasmaspray positive-ion mass spectra was a protonated molecular ion and very little fragmentation was evident. In the negative ionization mode, the plasmaspray method gave mass spectra showing more fragmentation, which resulted in additional structural information. The ability of trifluoroacetic acid to form negative cluster ions precluded its use as a mobile phase component. The minimum detectable amounts determined by the analysis in the positive-ion mode was compound-dependent, but generally ca. 10–150 ng. In many cases the compounds could be detected in urine extracts.     

Redescription of Branchinecta granulosa Daday, 1902 from Argentina (Crustacea: Branchiopoda)

The species Branchinecta granulosa Daday 1902, is redescribed on the basis of adult material from near Facundo (Chubut Province, Argentina). Its relationship to its regional congeners is outlined.     

Brefeldin A inhibits the formation of constitutive secretory vesicles and immature secretory granules from the trans-Golgi network.

The effects of brefeldin A (BFA) on membrane traffic between the trans-Golgi network (TGN) and the plasma membrane were investigated in intact PC12 cells and in a cell-free system derived from PC12 cells. In intact cells, BFA caused a virtually complete block of constitutive secretion, as indicated by the lack of release from, and accumulation in, the cells of a [35S]sulfate-labeled heparan sulfate proteoglycan (hsPG). Pulse-chase experiments with [35S]sulfate followed by subcellular fractionation showed that this block was due to the inhibition of formation of constitutive secretory vesicles (CSVs) from the TGN. BFA did not block the depolarization-induced release of [35S]sulfate-labeled chromogranin B (CgB) and secretogranin II (SgII) from secretory granules formed prior to the addition of the drug, showing that BFA does not block secretory granule fusion with the plasma membrane. The presence of BFA did, however, prevent the appearance of [35S]sulfate-labeled CgB and SgII in secretory granules, indicating that the drug inhibits the formation of secretory granules from the TGN. Evidence for a direct block of vesicle formation by BFA was obtained using a cell-free system derived from [35S]sulfate-labeled PC12 cells. In this system, low concentrations of BFA (5 micrograms/ml) inhibited the formation of the hsPG-containing CSVs and that of the SgII-containing secretory granules from the TGN to the same extent (50-60%) as, and in a non-additive manner with, the nonhydrolyzable GTP analogue GTP gamma S. Consistent with the inhibitory effects of BFA on vesicle formation from the TGN, BFA treatment of intact PC12 cells led to the hypersialylation of CgB, which presumably was due to the increased residence time of the protein in the TGN. In conclusion, our data are consistent with, and allow the generalization of, the concept that the BFA-induced block of anterograde membrane traffic results from the inhibition of vesicle formation from a donor compartment.     

Asymmetric reduction of ketones with resting cells of Sulfolobus solfataricus

The method of resting cells has been of interest in the development of biocatalysts applied to organic reactions.This article deals with the use of resting cells of a thermophilic archaebacterium Sulfolobus solfataricus, in the asymmetric reduction of acyclic, cyclic, and aromatic ketones. The system allows the continuous regeneration of endogenous coenzyme with the coupled substrate approach. The results indicate that the direction of hydride attack was equatorial on the re face of the carbonyl group of substrates producing (S)-alcohols with a good optical yield. A convenient system for the reuse of resting cells has been set out to synthesize (S)-alcohols on a preparative scale.