ERbeta protein expression in female cynomolgus monkey and CF-1 mouse brain: Western analysis

In humans and rodents, multiple ERbeta variants with sizes ranging from 477-549 amino acids (aa) have been described. The identification of these variants in target tissues has important implications for estrogen signaling and cellular responsiveness. Western blot analysis using two anti-ERbeta antibodies specific for mammalian ERbeta sequences (PA1-310B and PA1-311) was employed to examine ERbeta protein expression in neural tissues from ovariectomized (OVX) cynomolgus macaques and CF-1 mice as well as to assess potential regulatory effects of acute and extended estradiol (E(2)) treatment. In hypothalamic extracts from both species, a single ERbeta immunoreactive (ERbeta-ir) band was detected at approximately 54 kDa, corresponding to the expected molecular weight for ERbeta477 and/or 485. In cynomolgus females, oral E(2) administration for 16 weeks had no apparent effect on hypothalamic ERbeta protein expression. In mouse, a single injection of E(2) did not change hypothalamic ERbeta protein levels 1.5, 4, 8, 16, or 24 h after injection. Extending the hormonal treatment to 4 or 21 days in OVX female mice also had no effect on the level of hypothalamic ERbeta protein. Additional regional analyses in female mouse brain with PA1-310B antibody showed that a second, 59 kDa ERbeta-ir band was present in cortex, striatum, hippocampus, and amygdala that could represent one or both of the larger ERbeta variants (530 and 549aa). The expression level of the second ERbeta isoform exhibited regional variation, with the strongest immunoreactivity detected in cortex and amygdala. Elucidating the functions of these ERbeta isoforms in the CNS will facilitate our understanding of the tissue- and promoter-specific actions of estrogen.     

Temperature controls on aquatic bacterial production and community dynamics in arctic lakes and streams

The impact of temperature on bacterial activity and community composition was investigated in arctic lakes and streams in northern Alaska. Aquatic bacterial communities incubated at different temperatures had different rates of production, as measured by ¹⁴C‐leucine uptake, indicating that populations within the communities had different temperature optima. Samples from Toolik Lake inlet and outlet were collected at water temperatures of 14.2°C and 15.9°C, respectively, and subsamples incubated at temperatures ranging from 6°C to 20°C. After 5 days, productivity rates varied from 0.5 to ～13.7 µg C l^?1 day^?1 and two distinct activity optima appeared at 12°C and 20°C. At these optima, activity was 2‐ to 11‐fold higher than at other incubation temperatures. The presence of two temperature optima indicates psychrophilic and psychrotolerant bacteria dominate under different conditions. Community fingerprinting via denaturant gradient gel electrophoresis (DGGE) of 16S rRNA genes showed strong shifts in the composition of communities driven more by temperature than by differences in dissolved organic matter source; e.g. four and seven unique operational taxonomic units (OTUs) were found only at 2°C and 25°C, respectively, and not found at other incubation temperatures after 5 days. The impact of temperature on bacteria is complex, influencing both bacterial productivity and community composition. Path analysis of measurements of 24 streams and lakes sampled across a catchment 12 times in 4 years indicates variable timing and strength of correlation between temperature and bacterial production, possibly due to bacterial community differences between sites. As indicated by both field and laboratory experiments, shifts in dominant community members can occur on ecologically relevant time scales (days), and have important implications for understanding the relationship of bacterial diversity and function.     

Injury to the Throwing Arm—A Study of Traumatic Changes in the Elbow Joints of Boy Baseball Players

X-ray studies were made of both elbows of 162 boys in the 9 to 14 year age group, divided into three categories: Pitchers, non-pitchers, and a control group who had never played organized baseball.Changes involving the medial epicondylar epiphysis and opposing articular surfaces of the capitulum and head of radius in the throwing arm appeared to be in direct proportion to the amount and type of throwing. The most striking changes were in the arms of pitchers. Some degree of accelerated growth, separation and fragmentation of the medial epicondylar epiphyses was noted in the throwing arm of all 80 pitchers in the study. Five cases of traumatic osteochondritis of the capitulum and head of radius, and one case of juvenile osteochondritis of the head of the radius were also found among the pitchers.Better medical supervision and stress on prevention are needed, especially in the Southern California area where climatic conditions favor prolonged seasons and throwing practice the year around.     

A sliding docking interaction is essential for sequential and processive phosphorylation of an SR protein by SRPK1

The 2.9 A crystal structure of the core SRPK1:ASF/SF2 complex reveals that the N-terminal half of the basic RS domain of ASF/SF2, which is destined to be phosphorylated, is bound to an acidic docking groove of SRPK1 distal to the active site. Phosphorylation of ASF/SF2 at a single site in the C-terminal end of the RS domain generates a primed phosphoserine that binds to a basic site in the kinase. Biochemical experiments support a directional sliding of the RS peptide through the docking groove to the active site during phosphorylation, which ends with the unfolding of a beta strand of the RRM domain and binding of the unfolded region to the docking groove. We further suggest that the priming of the first serine facilitates directional substrate translocation and efficient phosphorylation.     

Spread and persistence of a rugulosin-producing endophyte in Picea glauca seedlings

We have studied Picea glauca (white spruce) endophyte colonization and its affect on the growth of Choristoneura fumiferana (spruce budworm). Here we examine the spread and persistence of a rugulosin-producing endophyte and rugulosin in needles from trees maintained in the nursery, as well as in trees planted in a test field site. Additionally, we report toxicity of rugulosin against three P. glauca needle herbivores: C. fumiferana, Lambdina fiscellaria (hemlock looper) and Zeiraphera canadensis (spruce budmoth). Reduction in body weight for both the C. fumiferana and L. fiscellaria were observed at 25 and 50 μm, respectively, and head capsules were reduced at 100 and 150 μm. Z. canadensis larvae did not perform as well in tests due to an Aspergillus fumigatus infection, but were shown to be lighter when tested with 100 and 150 μm compared with controls. The endophyte and its toxin were shown to spread throughout the nursery-grown seedlings. After 3.5 and 4.5 y post-inoculation (one and two years in the test site), the inoculated endophyte and its toxin had remained present with an average rugulosin concentration of 1 μg g⁻¹.     

3-Methylindole inhibits lipid peroxidation

The mechanism of pneumotoxicity of 3-methylindole has been postulated to occur via protein alkylation or lipid peroxidation. This report describes the effects of the addition of 3-methylindole to goat lung microsomes to evaluate the possibility that this xenobiotic may increase NADPH-supported lipid peroxidation. Concentrations of malondialdehyde were measured as an index of lipid peroxidation. Instead of a stimulation of lipid peroxidation by 3-methylindole, a complete inhibition of lipid peroxidation was produced by concentrations of 3-methylindole as low as 10 microM. The addition of 3-methylindole to actively peroxidizing microsomes (NADPH-supported) caused an immediate cessation of malondialdehyde production. These results demonstrate that 3-methylindole pneumotoxicity does not proceed by a mechanism of lipid peroxidation, but in fact, this molecule may act as an effective antioxidant to prevent lipid peroxidation in pulmonary tissue.     

The effects of non-homology in RAPD bands on similarity and multivariate statistical ordination in Brassica and Helianthus

 In order to estimate the impact of mis-coding non-homologous, co-migrating DNA bands as homologous, two sets of data were utilized. Analyses were conducted using three Helianthus species in which each co-migrating band had previously been confirmed. Comparisons of the similarities between these three Helianthus species using the original 177 RAPD bands and the corrected, homology verified, 197 RAPD band data set revealed that the triangular relationship among these three species was almost identical in both data sets. The non-homology errors in the Helianthanus data sets were found to be random. These random errors merely reduced the absolute similarities, but not the relative similarities nor the relationships among the taxa, in principal-coordinate-analysis ordination. Analyses of RAPDs for the classical Brassica U triangle were made by inserting random non-homologies for 5, 10, 15 and 20% of the original 220 RAPD bands. These analyses revealed a progressive decrease in similarities and less loading on the first two axes in principal coordinate analysis (PCO). However, the basic U triangle of relationships among these six Brassica species was maintained. It appears that if errors in homology of co-migrating DNA bands are random, this will have little effect on the relative similarities and on PCO ordination. This helps explain the successful use of RAPDs at the specific level. Received: 6 December 1997 / Accepted: 11 December 1997     

Fine structure of the tip of the labellar taste hair of the blow flies,Phormia regina (Mg.) and Calliphora vicina R.-D. (Diptera,Calliphoridae)

Summary The labellar taste hairs of the blow flies, Phormia regina and Calliphora vicina, have an opening mechanism at the tip which consists of two stump cuticular prongs and a funnel-like cuticular pouch. Opening and folding of these structures are regulated by the pressure within the dendrite-free lumen of the hair. The extrusion of viscous substance at the tip of the taste hair is possible through spongy cuticle and one pore in each prong; it seems likewise to depend on the pressure within the dendrite-free lumen and results in regional collapsing of this lumen. Described and discussed are: The cuticle and pores of the structures at the hair tip, pore filaments which extend from the dendrites, and the number and arrangement of the dendrites.This work was supported by a grant from the 7USDA, Entomology Research Division, Beltsville, Md., and the grant GB-13500 from the National Science Foundation.We thank Dr. J. F. Worley, USDA, Plant Science Research Division, Beltsville, Md., for his collaboration in fluorescence microscopy.