中国皿蛛科——新纪录属及天山前延首蛛的重描述（蜘蛛目：皿蛛科）

本文记述我国皿蛛科一新纪录属:前延首蛛届Archaraeoncus Tanasevitch 1987,并对天山前延首蛛A.tianshanicus(Hu et Wu,1989)n.comb.重新作了描述,本种的雌蛛系首次发现。本文还对Araeoncus tianschanica Hu et Wu 1989原学名命名的原始拚缀作了改正。文中测量数据均以mm为单位。     

The preparation of bile acid amides and oxazolines, II, the synthesis of the amides and oxazolines of ursodeoxycholic acid, deoxycholic acid, hyodeoxycholic acid and cholic acid

Bile acid amides and oxazolines were synthesized by a sequence of steps involving the reaction of the free bile acid with formic acid to yield the formyloxy derivative, preparation of the formyloxy acid chloride, condensation of the acid chloride with 2-amino-2-methyl-1-propanol to give the amide and, finally, cyclization of the amide with thionyl chloride to give the oxazoline. The oxazolines were characterized by physical constants, thin layer and gas-liquid chromatography and identified by elemental analysis and gas-liquid chromatography-mass spectrometry. Some of the bile acid oxazoline derivatives alter the activity of bacterial 7-dehydroxylases $\text{in vitro}$, and inhibit the growth of certain anaerobic bacteria in pure culture.     

Honeybee‐assisted wind pollination in bamboo Phyllostachys nidularia (Bambusoideae: Poaceae)?

Floral syndromes and pollination of three species of Phyllostachys bamboos were studied in Central China in 1999 and 2000. All were protogynous. Stigmas were receptive and had pollen deposited on them 2 days before anther dehiscence. The period of anthesis in the three bamboos was 3 days. Individual pollen grains of the three species were similar in size (30–40 μm in diameter) and had features typical of wind-pollinated plants. The ratios of pollen to ovules (p/o ratio) in P . nidularia , P . heteroclada and P . nuda were 6500, 12 700 and 33 000, respectively. Mean pollen loads on each flower (one ovule) of these three species were 7.3, 8.8 and 9.4 grains, respectively. Pollen transfer in P . heteroclada and P . nuda depended on wind, and no flower visitors were seen in the field. However, in P . nidularia , Apis cerana Fab. was a frequent pollen collector observed from 1200 to 1330 h. The visits undertaken by thousands of honeybees resulted in a large number of pollen grains being released from the anthers in a short time (10–15 min) in one day, which accelerated and synchronized the release of pollen from the anthers that seemed to enhance the chance of pollination. Given that honeybees played an indirect role in pollen transfer this could partly explain the low p/o ratio in P . nidularia . Reviewing the literature, we found insect visits to flowers of bamboos were not infrequent phenomena. We suggest pollination efficiency should be considered as one selective factor in attempts to understand mast flowering in bamboo. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 1–7.     

Species distribution and <Emphasis Type="Italic">in vitro</Emphasis> antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

Background  

In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis.     

Endothelial cell Ca2+ increases are independent of membrane potential in pressurized rat mesenteric arteries

In rat mesenteric arteries, the ability of ACh to evoke hyperpolarization of smooth muscle cells and consummate dilatation relies on an increase in endothelial cell cytosolic free [Ca2+] and activation of Ca2+-activated K+ channels (KCa). The time course of average and spatially organized rises in endothelial cell [Ca2+]i and concomitant effects on membrane potential were investigated in individual cells of pressurized arteries and isolated sheets of native cells stimulated with ACh. In both cases, ACh stimulated a sustained and oscillating rise in endothelial cell [Ca2+]i. Overall, the oscillations remained asynchronous between cells, yet occasionally localized intercellular coordination became evident. In pressurized arteries, repetitive waves of Ca2+ moved longitudinally across endothelial cells, and depended on Ca2+-store refilling. The rise in endothelial cell Ca2+ was associated with sustained hyperpolarization of endothelial cells in both preparations. This hyperpolarization was also evident when recording from smooth muscle cells in pressurized arteries, and from resting membrane potential, selective inhibition of small-conductance K Ca (SK Ca) with apamin (50 nM) was sufficient to inhibit this response. In the presence of phenylephrine-tone, both apamin and the selective inhibitor of intermediate conductance K Ca (IK Ca) TRAM-34 (1 microM) were required to inhibit the non-nitric oxide-mediated dilatation to ACh. When hyperpolarization of endothelial cells was fully prevented either with inhibitors of K Ca or in KCl (35 mM)-depolarized cells, both the time course and frequency of oscillations in endothelial cell [Ca2+]i to ACh were unaffected. Together, these data show that although a rise in endothelial cell [Ca2+]i stimulates hyperpolarization, depletion of intracellular stores with ACh stimulates Ca2+-influx which is not significantly influenced by the increase in cellular electrochemical gradient for Ca2+ caused by that hyperpolarization.     

Structure and diversity of the Mesozoic wood genus Xenoxylon in Far East Asia: implications for terrestrial palaeoclimates

Although the faunal elements of Far East Asian Mesozoic terrestrial biota have attracted much attention in recent years, their palaeoecology remains poorly known. In particular, features of the palaeoclimate are highly controversial. To address this point we used the Mesozoic fossil wood Xenoxylon , a genus recognized as an indicator of wet temperate biotopes and which is common in the area during the Carnian–Maastrichtian interval. We re-appraised bibliographic data and gathered new data for Xenoxylon in the Mesozoic of Far East Asia. This demonstrated that previous taxonomic approaches to the genus have been so far idiosyncratic. We examined the anatomical diversity of morphogenus Xenoxylon in Far East Asia and compared it to that of samples from Europe. This indicates that in an area centred on north-eastern China, Xenoxylon reached a level of anatomical diversity unmatched elsewhere in the world. We hypothesize that this diversity witnesses the persistence of palaeoecological conditions particularly suitable for Xenoxylon and that a wet temperate climate prevailed over most of the area throughout the Carnian–Maastrichtian interval. It is in this setting that the famous Jehol Biota probably evolved.