Application of the imidate procedure to α-d-galactosyltion

Using the imidate procedure, 2,3,4,6-tetra-O-benzyl-1-O-(N-methylacetimidoyl)-β-d-galactopyranose was condensed with various monosaccharides to provide, in good yield and with high stereoselectivity, α-linked disaccharides.     

Whole body content and turnover of Cs and K

Biological Trace Element Research - In persons who had accumulated radiocesium from the fallout of the Chernobyl nuclear reactor accident, the amount of radiocesium and radiopotassium was measured...     

Thyroid dose assessment for the Chernigov region (Ukraine): Estimation based on131I thyroid measurements and extrapolation of the results to districts without monitoring

Based on the results of¹³¹I thyroid activity measurements in three districts of the Chernigov region (Ukraine), individual doses were calculated and an approach of the age dependence of the average thyroid exposure was derived. Using the relationships between the thyroid doses and the¹³⁷Cs deposition as well as the location relative to the Chernobyl Nuclear Power Plant (NPP), age-dependent average thyroid doses were extrapolated also for those settlements of this region where no monitoring measurements have been carried out. The highest doses were found in the west of the region with the lowest distance to the Chernobyl NPP. In this part, the highest mean of the thyroid dose in a settlement was 3.3 Gy for infants and 0.5 Gy for adults. The collective thyroid dose was 31000 and 27 000 person-Gy for children and adults, respectively. Based on this assessment, 140 and 21 excess thyroid cancer cases are predicted for children and adults, respectively. In the years 1989 to 1991, in the whole contaminated territory of the Ukraine 0.4–1.2 cases per 100000 children were observed. Although the absolute numbers are very small, this indicates the possibility of an increase in thyroid cancer morbidity among children. The same trend also seems to be indicated in the Chernigov region. A careful epidemiological study in the future is necessary to enable a final evaluation of radioinduced cancers in this region.     

Cell cycle mutation in Paramecium tetraurelia discriminates between sexual and vegetative functions

The temperature-sensitive mutation cc1 blocks a number of cell cycle processes in Paramecium including macronuclear DNA synthesis, oral morphogenesis, and the later stages of micronuclear mitosis. Oral morphogenesis and micronuclear mitosis also occur in the sexual pathway. This study shows that cc1 cells can proceed through conjugation or autogamy under restrictive conditions; neither stomatogenesis nor micronuclear mitosis is blocked. Fertilization and macronuclear determination occur normally, but DNA synthesis in macronuclear anlagen is blocked. Therefore, this mutation discriminates between oral replacement during meiosis and vegetative prefission stomatogenesis, and between mitotic spindle elongation during the pregamic and postzygotic divisions and spindle elongation during the vegetative cell cycle. These results point to a fundamental regulatory difference between morphogenesis in the vegetative and sexual pathways. © 1994 Wiley-Liss, Inc.     

Diel Production and Microheterotrophic Utilization of Dissolved Free Amino Acids in Waters Off Southern California

Diel patterns of dissolved free amino acid (DFAA) concentration and microheterotrophic utilization were examined in the spring and fall of 1981 in euphotic waters from the base of the mixed layer off the southern California coast. The average depths of the isotherms sampled were 19.2 m for spring and 9.0 m for fall. Total DFAA levels were generally higher in the spring than in the fall, 18 to 66 nM and 14 to 20 nM, respectively. Two daily concentration maxima and minima were observed for total DFAAs as well as for most individual DFAAs. Maxima were usually measured in the mid-dark period and in the early afternoon; minima were typically observed in early morning and late afternoon. Bacterial cell numbers reached maximal values near midnight in both seasons. These increases coincided with one of the total DFAA maxima. The second total DFAA maximum occurred in early to midafternoon, during the time of maximum photosynthetic carbon production and rapid dissolved amino acid utilization. Microbial metabolism (incorporation plus respiration) of selected ³H-amino acids was 2.7 to 4.1 times greater during the daylight hours. DFAA turnover times, based on these metabolic measurements, ranged between 11 and 36 h for the amino acids tested, and rates were 1.7 to 3.7 times faster in the daylight hours than at night. DFAA distributions were related to primary production and chlorophyll a concentrations. Amino acids were estimated to represent 9 to 45% of the total phytoplankton exudate. Microheterotrophic utilization or production of total protein amino acids was estimated as 3.6 μg of C liter⁻¹ day⁻¹ in spring and 1.9 μg of C liter⁻¹ day⁻¹ in the fall. Assimilation efficiency for dissolved amino acids averaged 65% for marine microheterotrophs.     

Synthesis of M and N active glycopeptides. Part of the N-terminal region of human glycophorin A

The synthesis of two series of glycopeptides, part of the N-terminal region of human glycophorin A, was accomplished starting from derivatives ofO--d-galactopyranosyl-(1–3)-O-(2-acetamido-2-deoxy--d-galactopyranosyl)-l-serine and-l-threonine.     

Achillea filipendulina Lam.: Chemical Constituents and Antimicrobial Activities of Essential Oil of Stem,Leaf, and Flower

In this study, we extracted the essential oils of the stem, leaf, and flower of Achillea filipendulina, analyzed them, and studied their antibacterial properties. Of 16, 53, and 35 compounds identified in the stem, leaf, and flowers, respectively, only five are present in all three segments of the plant. The essential oil of the stem was mainly composed of neryl acetate, spathulenol, carvacrol, santolina alcohol, and trans‐caryophyllene oxide. However, the main identified components of leaf were 1,8‐cineole, camphor, ascaridole, trans‐isoascaridole, and piperitone oxide and the main components of the flower oil were ascaridole, trans‐isoascaridole, 1,8‐cineole, p‐cymene, and camphor. The extracted oil from different segments demonstrated varying antibacterial properties against both Gram‐positive and Gram‐negative bacteria, demonstrated by disk, minimum inhibitory concentration, and minimum bactericidal concentration methods. These suggest that the application of all segments of aerial parts of A. filipendulina may have a better therapeutic effect in fighting pathogenic systems.     

SANS (USH1G) regulates pre-mRNA splicing by mediating the intra-nuclear transfer of tri-snRNP complexes

Splicing is catalyzed by the spliceosome, a compositionally dynamic complex assembled stepwise on pre-mRNA. We reveal links between splicing machinery components and the intrinsically disordered ciliopathy protein SANS. Pathogenic mutations in SANS/USH1G lead to Usher syndrome—the most common cause of deaf-blindness. Previously, SANS was shown to function only in the cytosol and primary cilia. Here, we have uncovered molecular links between SANS and pre-mRNA splicing catalyzed by the spliceosome in the nucleus. We show that SANS is found in Cajal bodies and nuclear speckles, where it interacts with components of spliceosomal sub-complexes such as SF3B1 and the large splicing cofactor SON but also with PRPFs and snRNAs related to the tri-snRNP complex. SANS is required for the transfer of tri-snRNPs between Cajal bodies and nuclear speckles for spliceosome assembly and may also participate in snRNP recycling back to Cajal bodies. SANS depletion alters the kinetics of spliceosome assembly, leading to accumulation of complex A. SANS deficiency and USH1G pathogenic mutations affects splicing of genes related to cell proliferation and human Usher syndrome. Thus, we provide the first evidence that splicing dysregulation may participate in the pathophysiology of Usher syndrome.     

Functional Dissection of the Drosophila melanogaster Condensin Subunit Cap-G Reveals Its Exclusive Association with Condensin I

The heteropentameric condensin complexes have been shown to participate in mitotic chromosome condensation and to be required for unperturbed chromatid segregation in nuclear divisions. Vertebrates have two condensin complexes, condensin I and condensin II, which contain the same structural maintenance of chromosomes (SMC) subunits SMC2 and SMC4, but differ in their composition of non–SMC subunits. While a clear biochemical and functional distinction between condensin I and condensin II has been established in vertebrates, the situation in Drosophila melanogaster is less defined. Since Drosophila lacks a clear homolog for the condensin II–specific subunit Cap-G2, the condensin I subunit Cap-G has been hypothesized to be part of both complexes. In vivo microscopy revealed that a functional Cap-G-EGFP variant shows a distinct nuclear enrichment during interphase, which is reminiscent of condensin II localization in vertebrates and contrasts with the cytoplasmic enrichment observed for the other EGFP-fused condensin I subunits. However, we show that this nuclear localization is dispensable for Cap-G chromatin association, for its assembly into the condensin I complex and, importantly, for development into a viable and fertile adult animal. Immunoprecipitation analyses and complex formation studies provide evidence that Cap-G does not associate with condensin II–specific subunits, while it can be readily detected in complexes with condensin I–specific proteins in vitro and in vivo. Mass-spectrometric analyses of proteins associated with the condensin II–specific subunit Cap-H2 not only fail to identify Cap-G but also the other known condensin II–specific homolog Cap-D3. As condensin II–specific subunits are also not found associated with SMC2, our results question the existence of a soluble condensin II complex in Drosophila.