悬钩子属种质的评价

在进行了７省悬钩子资源调查的基础上,在南京建立了悬钩子属田间基因库。３年来对田间基因库内保存并开花结果的３０个种进行了开花结果性状的记栽和评价。内容包括果实特征,糖、酸、维生素类、氨基酸、矿质元素含量分析,染色体计数等。分析了种间和种内多样性物存在及在良种选育中利用的可能性。     

广州抽水蓄能电站蓄水库蓄水初期浮游生物调查

对我国首座核电站配套工程的抽水蓄能电站水库蓄水初期的浮游生物进行了调查。蓄水水库由上下两水库组成。两水库的浮游生物种类组成显著不同。上水库浮游植物共记录到３０种（属）,浮游动物１２种（属）;下水库浮游植物１９种（属）;浮游动物２５种（属）。上下两水库浮游生物数量均较贫乏,表明浮游生物群落尚处于初期发育阶段,但在局部浅水处已出现小规模的蓝藻水花,认为是水库蓄水初期必然的结果     

Microbial flocculant from Arcuadendron sp. TS-49

Summary A flocculant was purified from the culture broth of Archuadendron sp. TS-49 by a series of precipitations with acetone, 60% ammonium sulfate-butanol, salting-out by dialysis, and cetylpyridinium chloride. The flocculating activity was observed most highly at pH 3.0 and markedly enhanced by the addition of salts, especially in the case of FeCl₃ or FeSO₄. This bioflocculant efficiently flocculated all tested solids, including various microorganisms and organic/ inorganic materials. Qualitative analyses of the bioflocculant showed that it might contain hexosamine, uronic acid, neutral sugar, and protein.     

Lipase-catalyzed synthesis of lysophosphatidic acid in a solvent free system

Summary The direct, lipase-catalyzed esterifications of glycerol-3-phosphate in an organic solvent system and in a solvent free system were carried out. In a solvent free system only, LPA synthesis could be achieved within the acceptable reaction time. Open reaction system was preferable to closed reaction system for LPA synthesis. Yield of LPA isolated by silica gel column chromatography was 32.3%.     

The effect of xanthate floatation reagents on bacterial leaching of chalcopyrite by Thiobacillus ferrooxidans

Summary Xanthate floatation compounds, added to cultures of Thiobacillus ferrooxidans leaching chalcopyrite, inhibited growth in the concentration range 1–10 mM and caused a drop in formation of soluble copper and iron. Maximum (80–90%) growth inhibition was at 10 mM for isobutyl-, amyl- and ethyl xanthate while isopropyl xanthate was innocuous but caused a four-fold increase in lag phase. Copper production was depressed by 30% for isopropyl-, 53% for isobutyl-, ethyl- and 77% for amyl xanthate at 10 mM additions.     

KINETICS OF CELL DEATH IN THE CYANOBACTERIUM ANABAENA FLOS-AQUAE AND THE PRODUCTION OF DISSOLVED ORGANIC CARBON1

Kinetics of cell death and the production of dissolved organic carbon (DOC) were investigated in Anabaena flos-aquae (Lyngb.) Bréb grown on three different N sources (N₂nitrate, and ammonium) in a phosphorus (P)-limited chemostat. The fraction of live cells in the total population increased as growth rate increased with decreasing P limitation. Cell death was less in nitrate and ammonium media than in N₂. The specific death rate (γ), when calculated as the slope ofv^?1_x vs. D^?1, where v_xand D are live cell fraction (or cell viability) and dilution rate, respectively, was 0. 0082 day^?1 in N₂and 0.0042 day^?1 in nitrate. The slope of the plot in ammonium culture was not significant; however, the value of the live cell fraction was within the range for the NO^?₃culture. The fraction of live vegetative cells in N₂ culture was constant at all growth rates and the increase in the overall live cell fraction with growth rate was due entirely to an increase in live heterocysts. Live heterocysts comprised 3.5% of the total cells at a growth rate of 0.25 day^?1 and increased to 6.3% at 0.75 day^?1 with the ratio of live heterocysts to live vegetative cells linearly increasing with growth rate. The fraction of live vegetative cells was invariant in nitrate cultures us in N₂cultures. The live heterocysts fraction also increased with growth rate in nitrate cultures, along with the live heterocysts : live vegetative cells ratio, but the level was lower than in N₂cultures. DOC released from dead cells increased inversely with growth rate in N₂from 36.4% of the total DOC at a growth rate of 0.75 day^?1 to 54.15% at 0.25 day^?1. The contribution of cell death to the total DOC production in nitrate and ammonium media was significantly less than that under N₂DOC from dead cells consisted mainly of high-molecular-weight compounds, whereas DOC excreted from live cells was largely of low molecular weight.     

Ragweed sensitization alters pulmonary vascular responses to bronchoprovocation in beagle dogs

Theodorou, Andreas, Natalie Weger, Kathleen Kunke, KyooRhee, David Bice, Bruce Muggenberg, and Richard Lemen. Ragweed sensitization alters pulmonary vascular responses to bronchoprovocation in beagle dogs. J. Appl. Physiol.83(3): 912-917, 1997.In ragweed (RW)-sensitized beagle dogs, wetested the hypothesis that reactivity of the pulmonary vasculature wasenhanced with aerosolized histamine (Hist) and RW. Seven dogs wereneonatally sensitized with repeated intraperitoneal RW injections, and12 dogs were controls (Con). The dogs were anesthetizedwith intravenous chloralose, mechanically ventilated, and instrumentedwith femoral arterial and pulmonary artery catheters. Specific lungcompliance(CL_sp),specific lung conductance (G_sp),systemic vascular resistance index, and pulmonary vascular resistanceindex (PVRI) were measured before and after bronchoprovocation withHist and RW. After Hist inhalation (5 breaths of 30 mg/ml), both Conand RW dogs had significant (P < 0.05) decreases inCL_sp(51 ± 4 and 53 ± 5%, respectively) andG_sp (65 ± 5 and69 ± 3%, respectively), but only RW-sensitized dogs had asignificant increase in PVRI (38 ± 10%). After RW inhalation (60 breaths of 0.8 mg/ml), only RW-sensitized dogs had significant increases (62 ± 20%) in PVRI and decreases inG_sp (77 ± 4%) and CL_sp(65 ± 7%). We conclude that, compared with Con,RW-sensitized beagle dogs have increased pulmonary vasoconstrictiveresponses with Hist or RW inhalation.

     

Ginkgolide B production in cultured cells derived from Ginkgo biloba L. leaves

Callus cultures and cell suspension cultures derived from Ginkgo biloba L. leaves produced ginkgolidc B. In cell suspension cultures, the production reached a maximum by the 13th day of subculture and followed by a sharp decrease. The medium of Murashige and Skoog induced the highest ginkgolide B content in cultures while the medium of Schenk and Hildebrandt promoted cell growth. For the maximal production of ginkgolide B, cells were cultured in Murashige and Skoog medium modified to contain 1.0 mg/l of -naphthaleneacetic acid, 0.1 mg/1 of kinetin, 30 g/1 sucrose and 1.25 mM potassium phosphate with a molar ratio of ammonium to nitrate ions of 1 3.Abbreviations B5 Gamborg et al (1968) medium - GKB Ginkgolide B - MS Murashige and Skoog (1962) medium - NAA -naphthaleneacetic aicd - SH Schenk and Hildebrandt (1972) medium