Volatile components of developing tomato fruit grown under field and greenhouse conditions

Volatile components of field- and glass greenhouse-grown tomatoes(Lycopersicon esculentum MILL., variety, V. R. Moscow) of differentmaturities were studied by gas-liquid and thin-layer chromatography.The following components were separated and identified: isobutylalcohol, isopentyl alcohol, hexyl alcohol, 2-methyl-3-hexanol,isovaleraldehyde, caproaldehyde, benzaldehyde, furfural, isopentylacetate, isopentyl butyrate, isopentyl isovalerate, butyl hexanoate,hexyl hexanoate, methyl salicylate and -pinene. Chromatogramswere consistent for both field- and greenhouse-grown tomatoesat all stages of maturity. Except for isovaleraldehyde and hexylalcohol, the biosynthesis of volatile components increased alongwith the growth of fruit. Isovaleraldehyde and hexyl alcohol,presumed to give the "green leafy" aroma of tomatoes, were foundto be in their highest concentrations at the breaker and thelarge-green stages, respectively. ¹This research was supported by a research grant—UI 00449—fromthe National Center for Urban and Industrial Health, U. S. PublicHealth Service.     

Glucose uptake in human and animal muscle cells in culture

Human muscle cells were grown in culture from satellite cells present in muscle biopsies and fusion-competent clones were identified. Hexose uptake was studied in fused myotubes of human muscle cells in culture and compared with hexose uptake in myotubes of the rat L6 and mouse C2C12 muscle cell lines. Uptake of 2-deoxyglucose was saturable and showed an apparent Km of about 1.5 mM in myotubes of all three cell types. The Vmax of uptake was about 6000 pmol/(min.mg protein) in human cells, 4000 pmol/(min.mg protein) in mouse C2C12 muscle cells, and 500 pmol/(min.mg protein) in L6 cells. Hexose uptake was inhibited approximately 90% by cytochalasin B in human, rat, and mouse muscle cell cultures. Insulin stimulated 2-deoxyglucose uptake in all three cultures. The hormone also stimulated transport of 3-O-methylglucose. The sensitivity to insulin was higher in human and C2C12 mouse myotubes (half-maximal stimulation observed at 3.5 X 10(-9) M) than in rat L6 myotubes (half-maximal stimulation observed at 2.5 X 10(-8) M). However, insulin (10(-6) M) stimulated hexose uptake to a larger extent (2.37-fold) in L6 than in either human (1.58-fold) or mouse (1.39-fold) myotubes. It is concluded that human muscle cells grown in culture display carrier-mediated glucose uptake, with qualitatively similar characteristics to those of other muscle cells, and that insulin stimulates hexose uptake in human cells. These cultures will be instrumental in the study of human insulin resistance and in investigations on the mechanism of action of antidiabetic drugs.     

越南荨麻科楼梯草属和赤车属植物新记录

报道了7个楼梯草属和赤车属植物(荨麻科)新纪录,它们分别为锐齿楼梯草(E. cyrtandrifolium),变黄楼梯草(E. xanthophyllum),对叶楼梯草(E. sinense),宽叶楼梯草(E. platyphyllum),托叶楼梯草(E. nasutum),短叶赤车(P. brevifolia)和华南赤车(P. grijsii)。列出了各个物种的标本引证和地理分布情况。     

Regulation of cytosolic Ca2+ in clonal human muscle cell cultures

Human muscle cells were grown in culture and clonally selected for fusion potential. The concentration of cytoplasmic ionized calcium, [Ca2+]i, was measured in monolayers of fused myotubes using the Ca2+ indicator indo-1. The contributions of independent routes of Ca2+ influx and efflux to/from the cytoplasm on [Ca2+]i were investigated. The resting [Ca2+]i was 170-190 nM in different cell clones. Acetylcholine increased [Ca2+]i by about 2-fold in the presence of absence of extracellular Ca2+. Cell depolarization by K+ elevated [Ca2+]i about 3-fold, and this increase was largely dependent on extracellular Ca2+. Replacing Na+ by N-methylglucammonium+ raised [Ca2+]i greater than 5-fold, and 50% of this increase was dependent on extracellular Ca2+. All these increases in [Ca2+]i were transient, returning to basal [Ca2+]i within 2 min. It is concluded that cells in culture [Ca2+]i can be elevated transiently by acetylcholine through Ca2+ release from intracellular stores, and by K through Ca2+ influx. The return to basal [Ca2+]i is due to Na+/Ca2+ exchange and Ca2+-ATPase activity.     

越南铁线莲属一新种

本文描述的产于越南的毛茛科Ranunculaceae铁线莲属Clematis一新种C. hagiangensis N. T. Do是欧亚大陆第一个具单性花的种, 在花构造方面与单性铁线莲组单性铁线莲亚组sect. Aspidanthera Spach subsect. Dioicae (Prantl) W. T. Wang的种类近缘, 但叶均为单叶, 萼片呈卵形或宽卵形而不同。在单性铁线莲亚组的种, 叶通常为复叶, 只在C. dimorphophylla W. T. Wang和C. variifolia W. T. Wang同时为单叶和复叶, 此外萼片呈长圆形、倒披针形或狭卵形。     

Helminths from the fish Dormitator maculatus (Osteichthyes: Eleotridae) from Alvarado, Veracruz, Mexico

Dormirator maculatus (n=184) was collected in the Alvarado Lagoon, Mexico during a year period (Oct. 1993-1994). In the helminthologic review, the presence of Clinostomum complanatum (82.3%), Neoechinorhynchus golvani (76.1%), Spiroxys sp. (21.3 %), and Camallanus sp. (6.2%) was registered. Reduction of the hematocrit caused by such infection is significant (t, a= 0.05).     

A novel lepidopteran sex pheromone produced by females of a Lithosiinae species, Lyclene dharma dharma, in the family of Arctiidae

Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produced three pheromone components (I-III), which strongly stimulated male antennae. Using GC-MS analysis and chemical derivatizations, the following structures were estimated: 6-methyl-2-octadecanone (I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-2-octadecanone (III). While the stereochemistry of the chiral centers could not be determined because it was difficult to collect a sufficient amount of the natural pheromone, the plain structures of I and II were confirmed by synthesis of the racemic mixtures starting from diols. These methyl-branched ketones have not been identified as a natural product, indicating that they constitute a new chemical group of lepidopteran female sex pheromones.     

Parasites of the Central American tapir Tapirus bairdii (Perissodactyla: Tapiridae) in Chiapas, Mexico

We analyzed 19 samples of Baird's tapir feces from La Sepultura Biosphere Reserve, collected between March and July 1999. We also took samples directly from a male tapir captured at the Montes Azules Biosphere Reserve. Both reserves are in Chiapas, Mexico. We used five techniques: flotation, MacMaster, micrometric, Ritchie's sedimentation and Ferreira's quantitative. In addition, we collected ectoparasites from animals captured in both reserves and from a captive couple from Tuxtla Gutierrez, Chiapas. These nematodes and protozoans were found: Agriostomun sp., Lacandoria sp., Neomurshidia sp., Trichostrongylus sp., Strongylus sp., Brachylumus sp, and an unidentified species of ancilostomaide. We also found Eimeria sp. and Balantidium coli, as well as the mites Dermacentor halli, Dermacentor latus, Amblyomma cajannense, Amblyomma coelebs, Amblyomma ovale, Anocentor nitens and Ixodes bicornis.     

Phylogenetic Analysis of Heterothallic Neurospora Species

We examined the phylogenetic relationships among five heterothallic species of Neurospora using restriction fragment polymorphisms derived from cosmid probes and sequence data from the upstream regions of two genes, al-1 and frq. Distance, maximum likelihood, and parsimony trees derived from the data support the hypothesis that strains assigned to N. sitophila, N. discreta, and N. tetrasperma form respective monophyletic groups. Strains assigned to N. intermedia and N. crassa, however, did not form two respective monophyletic groups, consistent with a previous suggestion based on analysis of mitochondrial DNAs that N. crassa and N. intermedia may be incompletely resolved sister taxa. Trees derived from restriction fragments and the al-1 sequence position N. tetrasperma as the sister species of N. sitophila. None of the trees produced by our data supported a previous analysis of sequences in the region of the mating type idiomorph that grouped N. crassa and N. sitophila as sister taxa, as well as N. intermedia and N. tetrasperma as sister taxa. Moreover, sequences from al-1, frq, and the mating-type region produced different trees when analyzed separately. The lack of consensus obtained with different sequences could result from the sorting of ancestral polymorphism during speciation or gene flow across species boundaries, or both.