Tg (9 HSA-MYC), a homozygous lethal insertion in the mouse

Transgenic mice generated with different DNA sequences were surveyed for possible homozygous mutant phenotypes. We found an embryonic lethal mutation in the transgenic mouse strain (MT-MYC12.4) containing the human c-myc gene. Embryos homozygous for the transgene die shortly after implantation. The strain MT-MYC12.4 carries approximately 50 tandem copies of the recombinant plasmid sequence. The 3 flanking sequence has been cloned and analyzed. It contains a unique sequence that has been conserved during evolution and maps to Chromosome (Chr) 9. This mutant has been designated Tg 9 (HSA-MYC).     

A protein-free diet changes synaptosomal membrane fluidity and tyrosine and glutamate transport

Synaptosomes were isolated from cerebrums of rats fed standard (20% protein) or protein-free diets for 30 days. Arrhenius plots of their (Na⁺/K⁺)ATPase activities revealed a transition temperature of 25.5°C for control rats and 23.4°C for rats on protein-free diet, indicating that the latter increases synaptosomal membrane fluidity. The only change observed in the composition of the synaptosomal membranes was a 26% decrease of sialic acid. In synaptosomes from rats on protein-free diet the uptake of tyrosine was slightly reduced while that of glutamate was not affected. However, the exit of glutamate was reduced.     

A predominantly nuclear protein affecting cytoplasmic localization of beta-actin mRNA in fibroblasts and neurons.

The localization of beta-actin mRNA to the leading lamellae of chicken fibroblasts and neurite growth cones of developing neurons requires a 54-nt localization signal (the zipcode) within the 3' untranslated region. In this study we have identified and isolated five proteins binding to the zipcode. One of these we previously identified as zipcode binding protein (ZBP)1, a 4-KH domain protein. A second is now investigated in detail: a 92-kD protein, ZBP2, that is especially abundant in extracts from embryonic brain. We show that ZBP2 is a homologue of the human hnRNP protein, KSRP, that appears to mediate pre-mRNA splicing. However, ZBP2 has a 47-amino acid (aa) sequence not present in KSRP. Various portions of ZBP2 fused to GFP indicate that the protein most likely shuttles between the nucleus and the cytoplasm, and that the 47-aa insert promotes the nuclear localization. Expression of a truncated ZBP2 inhibits the localization of beta-actin mRNA in both fibroblast and neurons. These data suggest that ZBP2, although predominantly a nuclear protein, has a role in the cytoplasmic localization of beta-actin mRNA.     

Ligninolytic properties of different white-rot fungi

Summary Seven white-rot fungi were examined for the production of ligninase, manganese peroxidase and laccase. All these enzymes were found inTrametes gibbosa andTrametes hirsuta. Only manganese peroxidase and laccase were produced byPycnoporus cinnabarinus,Coriolopsis polyzona,Stereum hirsutum,Dichomitus squalens andGanoderma valesiacum. All fungi decolorized Poly B-411 and Indulin AT plates with low-N medium. The differences in enzyme pattern indicate that different species of fungi may employ different modes of lignin metabolism.     

Site-specific protein dynamics in communication pathway from sensor to signaling domain of oxygen sensor protein, HemAT-Bs: Time-resolved Ultraviolet Resonance Raman Study

HemAT-Bs is a heme-based signal transducer protein responsible for aerotaxis. Time-resolved ultraviolet resonance Raman (UVRR) studies of wild-type and Y70F mutant of the full-length HemAT-Bs and the truncated sensor domain were performed to determine the site-specific protein dynamics following carbon monoxide (CO) photodissociation. The UVRR spectra indicated two phases of intensity changes for Trp, Tyr, and Phe bands of both full-length and sensor domain proteins. The W16 and W3 Raman bands of Trp, the F8a band of Phe, and the Y8a band of Tyr increased in intensity at hundreds of nanoseconds after CO photodissociation, and this was followed by recovery in ～50 μs. These changes were assigned to Trp-132 (G-helix), Tyr-70 (B-helix), and Phe-69 (B-helix) and/or Phe-137 (G-helix), suggesting that the change in the heme structure drives the displacement of B- and G-helices. The UVRR difference spectra of the sensor domain displayed a positive peak for amide I in hundreds of nanoseconds after photolysis, which was followed by recovery in ～50 μs. This difference band was absent in the spectra of the full-length protein, suggesting that the isolated sensor domain undergoes conformational changes of the protein backbone upon CO photolysis and that the changes are restrained by the signaling domain. The time-resolved difference spectrum at 200 μs exhibited a pattern similar to that of the static (reduced - CO) difference spectrum, although the peak intensities were much weaker. Thus, the rearrangements of the protein moiety toward the equilibrium ligand-free structure occur in a time range of hundreds of microseconds.     

猕猴单次及多次注射重组人白介素—11后的药代动力学及外周血小板计数变化

研究猕猴单次或多次静脉注射(iv)和皮下注射(sc)rhIL-11后药代动力学及周边血小板计数变化。ELISA法检测血清rhIL-11浓度,血细胞计数仪计数血小板。iv和sc注射50～400μg     

A functional gene array for detection of bacterial virulence elements

Emerging known and unknown pathogens create profound threats to public health. Platforms for rapid detection and characterization of microbial agents are critically needed to prevent and respond to disease outbreaks. Available detection technologies cannot provide broad functional information about known or novel organisms. As a step toward developing such a system, we have produced and tested a series of high-density functional gene arrays to detect elements of virulence and antibiotic resistance mechanisms. Our first generation array targets genes from Escherichia coli strains K12 and CFT073, Enterococcus faecalis and Staphylococcus aureus. We determined optimal probe design parameters for gene family detection and discrimination. When tested with organisms at varying phylogenetic distances from the four target strains, the array detected orthologs for the majority of targeted gene families present in bacteria belonging to the same taxonomic family. In combination with whole-genome amplification, the array detects femtogram concentrations of purified DNA, either spiked in to an aerosol sample background, or in combinations from one or more of the four target organisms. This is the first report of a high density NimbleGen microarray system targeting microbial antibiotic resistance and virulence mechanisms. By targeting virulence gene families as well as genes unique to specific biothreat agents, these arrays will provide important data about the pathogenic potential and drug resistance profiles of unknown organisms in environmental samples.     

Serum cholesterol and triglycerides in postpartum beef cows and their relationship to the resumption of ovulation

The variations in lipid metabolism according to the physiological stage and their relationship to the resumption of postpartum ovarian cyclicity were assessed in Limousine beef cows fed a grass diet over 3 yr. Weekly blood samples were collected from 59 cows beginning 10 wk before to 20 wk after calving to evaluate serum cholesterol and triglyceride concentrations and electrophoretic lipoprotein fractions. After parturition, progesterone concentrations were also measured at weekly intervals to determine time of resumption of ovulation. Cows were categorized by resumption of postpartum ovarian cyclicity into 3 groups: early (4 to 6 wk post partum, n = 36); mid (7 to 10 wk post partum, n = 46) and late (after 11 wk post partum, n = 38). Higher serum triglyceride values (P<0.05) were observed during the last 10 wk of pregnancy (0.36+/-0.15 g/L) than during the first 20 wk of suckling (0.29+/-0.09 g/L). Cholesterol values decreased significantly (P<0.05) at the end of pregnancy, were minimal (1.01+/-0.03 g/L) at parturition, and increased again up to 9 wk post calving. Increased cholesterolemia and low serum triglyceride values after calving could be linked to the increased bovine alpha-lipoprotein fraction and decreased beta fraction. Serum triglyceride concentrations were not related to the resumption of postpartum ovarian cyclicity. Higher serum cholesterol values were observed from 2 wk before to 4 wk after calving in cows with early rather than mid and late resumption of ovarian cyclicity. Therefore, modifications in lipid metabolism during the puerperium seem to be related to resumption of cyclicity during the early postpartum period.     

Projecting future grassland productivity to assess the sustainability of potential biofuel feedstock areas in the Greater Platte River Basin

This study projects future (e.g., 2050 and 2099) grassland productivities in the Greater Platte River Basin (GPRB) using ecosystem performance (EP, a surrogate for measuring ecosystem productivity) models and future climate projections. The EP models developed from a previous study were based on the satellite vegetation index, site geophysical and biophysical features, and weather and climate drivers. The future climate data used in this study were derived from the National Center for Atmospheric Research Community Climate System Model 3.0 ‘SRES A1B’ (a ‘middle’ emissions path). The main objective of this study is to assess the future sustainability of the potential biofuel feedstock areas identified in a previous study. Results show that the potential biofuel feedstock areas (the more mesic eastern part of the GPRB) will remain productive (i.e., aboveground grassland biomass productivity >2750 kg ha^?1 year^?1) with a slight increasing trend in the future. The spatially averaged EPs for these areas are 3519, 3432, 3557, 3605, 3752, and 3583 kg ha^?1 year^?1 for current site potential (2000–2008 average), 2020, 2030, 2040, 2050, and 2099, respectively. Therefore, the identified potential biofuel feedstock areas will likely continue to be sustainable for future biofuel development. On the other hand, grasslands identified as having no biofuel potential in the drier western part of the GPRB would be expected to stay unproductive in the future (spatially averaged EPs are 1822, 1691, 1896, 2306, 1994, and 2169 kg ha^?1 year^?1 for site potential, 2020, 2030, 2040, 2050, and 2099). These areas should continue to be unsuitable for biofuel feedstock development in the future. These future grassland productivity estimation maps can help land managers to understand and adapt to the expected changes in future EP in the GPRB and to assess the future sustainability and feasibility of potential biofuel feedstock areas.     

Population suppression of Bemisia tabaci (Hemiptera: Aleyrodidae) using yellow sticky traps and Eretmocerus nr. rajasthanicus (Hymenoptera: Aphelinidae) on tomato plants in greenhouses

We conducted three experiments for management of Bemisia tabaci (Gennadius) biotype ‘B’ on tomatoes under greenhouse conditions: (i) vertically placing yellow sticky cards either parallel or perpendicular to tomato rows at a rate of 1 per 3‐m row; (ii) releasing Eretmocerus sp. nr. rajasthanicus once at 30 adults/m² in the high whitefly density greenhouses (> 10 adults/plant), or twice at 15 adults/m² at a 5‐day interval in the low whitefly density greenhouses (< 10 adults/plant); and (iii) using combinations of yellow sticky cards that were placed vertically parallel to tomato rows and parasitoids released once at 30/m² in high whitefly density greenhouses or twice at 15/m² at a 5‐day interval in low whitefly density greenhouses. Our data show that yellow sticky cards trapped B. tabaci adults and significantly reduced whitefly populations on tomato. The yellow sticky cards that were placed parallel to tomato rows caught significantly more whitefly adults than those placed perpendicular to tomato rows on every sampling date. In the treatment where parasitoids were released once at 30/m² in high whitefly density greenhouses, the number of live whitefly nymphs were reduced from 4.6/leaf to 2.9/leaf in 40 days as compared with those on untreated plants on which live whitefly nymphs increased from 4.4/leaf to 8.9/leaf. In the treatment where parasitoids were released twice at 15/m² in low whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.1/leaf to 1.7/leaf in 20 days as compared with those on untreated plants on which numbers of live nymphs of B. tabaci increased from 2.2/leaf to 4.5/leaf. In the treatment of yellow sticky cards and parasitoid release once at 30/m² in high whitefly density greenhouses, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 7.2/leaf to 1.9/leaf, and in the treatment of yellow sticky cards and parasitoid release twice at 15/m² at a 5‐day interval at low whitefly density, the numbers of live nymphs of B. tabaci on tomato leaves were reduced from 2.5/leaf to 0.8/leaf; whereas the numbers of live nymphs of B. tabaci on untreated plants increased from 4.4/leaf to 8.9/leaf. An integrated program for management of B. tabaci on greenhouse vegetables by using yellow sticky cards, parasitoids and biorational insecticides is discussed.