Transport of Tryptophan into Brain from the Circulating, Albumin-Bound Pool in Rats and in Rabbits

Tryptophan is the only amino acid in the circulation that is bound by albumin, and previous studies have suggested that the brain tryptophan supply is a function of either the free or the albumin-bound pool of tryptophan in blood. Since the albumin molecule per se does not cross the brain capillary wall, i.e., the blood-brain barrier (BBB), the transport of tryptophan from the circulating albumin-bound pool may involve enhanced dissociation of tryptophan from the albumin binding sites within the cerebral microcirculation. This hypothesis was confirmed in the present studies wherein the dissociation constant (KaD) of albumin binding of tryptophan in the rat or rabbit brain microcirculation was measured in vivo. Brain extraction data for [14C]tryptophan determined with the carotid artery injection technique were fit to the Kety-Renkin-Crone equation modified for protein-bound solute. The KaD of albumin binding in the rat or rabbit brain microcirculation under pentobarbital anesthesia was 1.7 +/- 0.1 and 3.9 +/- 1.0 mM, respectively, as compared to the KD value measured in vitro with equilibrium dialysis, 0.13 +/- 0.03 mM. In contrast, the KaD value of albumin binding of tryptophan in vivo in the rabbit brain microcirculation was reduced by ether anesthesia to a value of 2.1 +/- 0.4 mM. This reduction in the KaD under ether anesthesia was associated with a 2.5-fold increase in cerebral blood flow. In addition, dialyzed rabbit serum caused a statistically significant inhibition in [14C]tryptophan influx during ether, but not pentobarbital, anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)     

长江中游鱼类寄生棘头虫区系的研究

经过3年10次调查,剖检湖北省宜都、黄冈两处江段所产72种鱼类,共计766尾。收集棘头虫10种,其中包括2新种和1新组合,即蛇鮈新棘吻虫(新种)Neoechinorhynchus saurogobi sp.nov.,长江丽棘虫(新种)Brentisentis yangtzensis sp.nov.(Illiosontidae),鲤丽棘虫(新组合)B.cyprini comb.nov.。对长江中游鱼类寄生棘头虫区系的特点进行了分析和探讨。     

Catecholamine-Sensitive Adenylate Cyclase in the White Perch (Roccus americanus) Retina: Evidence for β-Adrenergic and Dopamine Receptors Linked to Adenylate Cyclase

We have examined the catecholamine-sensitive adenylate cyclase in the retina of the white perch (Roccus americanus). Both dopamine and the beta-adrenergic agonist isoproterenol stimulate cyclic AMP accumulation in this retina, but serotonin, an indoleamine, and phenylephrine, an alpha-adrenergic agonist, had no effect. The stimulation of adenylate cyclase by isoproterenol is more potent and effective than that of dopamine. The effects of dopamine and isoproterenol are mediated via independent dopamine and beta-adrenergic receptors. Haloperidol, a dopamine antagonist, blocks the stimulatory effect of dopamine but not of isoproterenol. Conversely, propranolol, a beta-adrenergic antagonist, blocks the stimulatory effect of isoproterenol but not of dopamine. The effects of dopamine and isoproterenol are not additive. In fractions of purified horizontal cells we found evidence for dopamine receptors linked to adenylate cyclase but did not find evidence for the presence of cyclase coupled beta-adrenergic receptors. The cellular location of the beta-adrenergic receptors is unknown. Our findings demonstrate the existence of both beta-adrenergic and dopamine receptors coupled to adenylate cyclase in the white perch retina. However, we did not find either epinephrine or norepinephrine, endogenous ligands of the beta-receptor, to be present in retinal extracts subjected to HPLC.     

Shape analysis of two sympatric coral species: Implications for taxonomy and evolution

Fourier shape analysis of Pleurodictyum americanum and P. dividua , favositid tabulate corals, from the Middle Devonian Hamilton Group of New York State, indicates that colony growth form is variable within species between environments, but that the range of variability in growth form is static through time. Pleurpdictyum dividua displays a columnar morphotype; however, P. dividua and P. americanum cannot be discriminated from one another based on colony shape alone. A major prediction of the punctuated equilibrium model of evolution is morphological stasis throughout the duration of a species. Harmonic means of assemblages of P. americanum show no persistent temporal trends. The range of harmonic means present among the oldest assemblages (Centerfield Limestone) are comparable to those among the youngest assemblages (Windom Shale) and to those in the intervening intervals. Character stasis in colony growth form lasted throughout a 2.5-3.5 my interval. In tabulate corals, where reproductive modes such as fragmentation have not been demonstrated, growth form may be useful in interpreting ancient environments. In addition, the tempo of evolution of growth form can be analyzed when sufficient morphological data are available from a wide distribution of environments. Thus, Fourier shape analysis of growth form provides a powerful tool for paleontologists to interpret the ecology and evolution of colonial marine animals.     

斜胸叶蝉属一新种（同翅目：叶蝉总科：耳叶蝉科）

本文记述耳叶蝉科斜胸叶蝉属一新种:黄缘斜胸叶蝉Epiclinata flavomarinata sp.nov.。标本采自我国西藏。文中描述了新种的外部形态及雄性外生殖器构造特征,并与近似种进行比较,附有主要特征图。模式标本保存于中国科学院动物研究所。     

条鳅亚科鱼类一新属新种

本文描述了云南省条鳅亚科鱼类一新属和一新种。根据形态特征并结合区系间的相互关系,探讨了属的分类地位。     

四川青城山优食蚜蝇属二新种记述（双翅目：食蚜蝇科）

本文记述四川青城山优食蚜蝇属Eupeodes 2新种:青优食蚜蝇Eupeodes (Eupeodes) qingchengshanensis和小优食蚜蝇Eupeodes(Eupeodes)parvus,均属于Eupeodes s.str.,亚属。模式标本保存于上海农学院昆虫标本室。     

内蒙古草蛉研究Ⅱ.五新种及二新记录种(脉翅目:草蛉科)

内蒙古地处我国北部边疆,全境以高原为主,西部为戈壁沙漠,东部为宽阔草原,绝大多数地区属于温带大陆性气候;动物地理区划属于古北区中亚细亚区的内蒙河西干草原区。该区现已知草蛉3属16种(包括本文所记述的5新种和2新记录种),其分布特点是以狭义的草蛉属Chrysopa为主,而且以广布于华北地区的叶色草蛉Chrysopaphyllochroma Wesmeal为代表种,新种的模式标本分别保存在中国科学院动物研究所及北京农业大学昆虫标本室。     

New genera of Copepoda (Poecilostomatoida) from the scleractinian coral Psammocora in New Caledonia

Three new monotypic genera of copepods (Poecilostomatoida) are associated with the hermatypic shallow-water coral Psammocora (Stephanaria) logianensis near Noumea, New Caledonia: in the Anchimolgidae, Lipochaetes extrusus (antenna 4-segmented, endopods absent in legs 3 and 4) and Dumbeana undulatipes (antenna 3-segmcntcd, endopod of leg 3 with formula 0 1; 0–2; 1,11,2; leg 4 endopod with 0 1:1); and in the Rhynchomolgidae; Emunoa proknta (leg 4 endopod with 0 1;II, antenna 4-segmented, mandible witli outer pointed process and inner row of spines). Copepoda (primarily Poecilostomatoida and Siphonostomatoida, but also relatively few Cyclopoida and Harpacticoida) are very frequent associates or parasites of Scleractinia. At present 245 species from 48 scleractinian coral genera are known. Species of these copepod associates, their host genera, and localities, described since (and those not included in) previous publications of the author are listed.     

Taxonomic identification of Streptomyces exfoliatus K10 and characterization of its poly(3-hydroxybutyrate) depolymerase gene

Abstract Using fungi grown on synthetic agar medium, we evaluated and compared the concentration of various H₂O₂-producing enzymes. Our results showed that oxidase production in solid medium was better than that found in liquid medium and as high as that detected in wood samples. High yields of oxidases made it possible to compare different oxidases in the same culture extracts and under different conditions. Our results also indicated that H₂O₂ production is ubiquitous in the white rot fungi tested and that enzyme levels are influenced by the substrate composition.