Mutant p21ras in vinyl chloride exposed workers

The production of mutations in cellular oncogenes such as ras is involved in the development of many human cancers. These mutations result in the expression of mutant forms of the encoded p21 protein which can potentially serve as a biomarker for this carcinogenic process. Workers exposed to vinyl chloride (VC) who are at risk for the development of the sentinel neoplasm angiosarcoma of the liver (ASL) represent a model population for the study of such a mutant p21ras biomarker, since VC is known to cause a specific ras mutation in ASL. In order to determine the relationship between VC exposure and this biomarker, serum samples from a cohort of 225 French VC workers and 111 age-sex-race-smoking-drinking matched unexposed controls were examined for the presence of mutant p21ras by immunoblotting with a mouse monoclonal antibody specific for the mutant protein. Stratifying the exposed workers by degree of VC exposure in estimated ppm-years by quartiles yielded a statistically significant trend for increasing odds ratio for sero-positivity of the p21ras biomarker with increasing exposure. These results suggest that this serum biomarker is related to VC exposure and may be an early indicator of carcinogenic risk in exposed individuals.     

武陵山东部蚤类区系及不同样地群落物种多样性比较

于2000～2004年对武陵山东部7个不同样地、3个不同海拔梯度和6个不同生境类型的蚤类,进行了5年调查与研究.结果:1)在获得的7科17属30种4 320只蚤类中,有4种为古北界种类,占13.33%,22种为东洋界种类,占73.34%,4种为广布种,占13.33%;该结果与云南无量山及临沧地区的蚤类有着相同或相似的区系渊源,而与一江之隔的大巴山东部地区区系则明显不同,该地区以古北界成分为优势;2)武陵山东部地区蚤类的垂直分布规律主要表现在,1 100 m以下主要为东洋界成分,1 200 m以上有少量古北界种类分布,并随海拔升高,古北界成分略有增加;3)在7个不同样地中,物种丰富度和个体数量随海拔升高而增加,在优势种上,多数样地以偏远古蚤为优势,但在优势数量上缺乏明显规律性,并不是随海拔升高而增加;4)在6个不同生境类型中,优势种与优势数量都具明显的规律性,其中以偏远古蚤为主分为两组,山脊侧缘林、小溪山边林和坡地林为一组,人工林和农田山侧灌木林为另一组,前者平均优势数量达80.03%,后者优势数量在31.56%～48.92%之间;5)相似性系数(q值):在整个山体多数样地中,由北向南相似性系数(q值)随海拔降低和空间距离增大而逐渐降低,仅绿丛坡与牛庄、绿丛坡与独岭有例外,表明整个山体植被的片断化、或斑块化,一方面加剧或减低了样地与样地之间蚤类群落的相似程度,另一方面还要受海拔及空间距离的双重影响与制约,即海拔高度和空间距离愈大,蚤类群落的相似性及多样性越低,山体的片断、斑块或破碎化就越明显,这显然与人为过多或过频干扰有关.     

中国苦苣苔科一新记录属——四轮苣苔属

该文报道了中国苦苣苔科(Gesneriaceae)一新记录属——四轮苣苔属(Tetraphyllum Griff. ex C. B. Clarke)。该新记录属,即四轮苣苔属仅有3种,其中密花四轮苣苔[T. confertiflorum(Drake)B. L. Burtt]在我国首次记录。该研究提供了该属的形态描述和分种区别特征,并提供了该种的详细形态描述及彩色照片。凭证标本馆藏于广西植物研究所标本馆(IBK)和上海辰山植物标本馆(CSH)。     

Leptomonas lactosovorans n. sp., a Lactose-Utilizing Trypanosomatid: Description and Nutritional Requirements1

Leptomonas lactosovorans n. sp. is described from the gut of the reduviid hemipteran Zelurus martinsi. It can be grown in a defined medium. The requirements for amino acids, vitamins, purine, and heme were similar to those established for Crithida fasciculata. Growth is stimulated by aeration. Generation time is longer than for any other insect trypanosomatid described; its utilization of lactose as a carbon source is a unique feature among trypanosomatids.     

Response of workers of Atta sexdens rubropilosa (Hymenoptera: Formicidae) to mandibular gland compounds of virgin males and females

Abstract.  The secretion from the mandibular glands of males of the leaf-cutting ant Atta sexdens rubropilosa is responsible for the reaction of workers outside the nest at the time of sexual swarming. Workers respond with excitability and aggression when presented with the natural mixture of 4-methyl-3-heptanol and 4-methyl-3-heptanone, which is contained in the secretion of the male mandibular glands. Workers respond quickly to fractional amounts of one male equivalent. 4-Methyl-3-heptanone, from the virgin female mandibular glands causes much less response in workers, whereas an equimolar mixture of male and female pheromones gives a still less clear response. The male pheromone plays the most important part in the communication of workers outside the nest at this time.     

Polyethism and nestmate recognition in the alarm reaction of Atta leaf-cutting ants

Abstract.  Ethological studies are conducted under laboratory conditions using workers of Atta sexdens sexdens and Atta opaciceps collected from field colonies to investigate the mechanisms involved in the alarm response and intra-specific recognition in leaf-cutting ants. Hexane extracts from the heads of gardeners and generalist workers elicit higher levels of alarm response in foragers from the same colony than do mandibular gland extracts from foragers and soldiers, indicating that gardeners, generalists and foragers are primarily responsible for the production of alarm pheromone. Foragers subjected to extracts from non-nestmates exhibit significantly greater alarm responses than are induced by similar extracts derived from nestmate workers, suggesting that the alarm pheromone may have a role in nestmate recognition.     

金喜楼梯草(荨麻科),越南楼梯草属植物一新种

对产自越南的荨麻科楼梯草属植物一新种金喜楼梯草（Elatostema kimhyense Y.G.Wei & V.T.Do）作了描述和绘图。该种生长于海拔350~400和1 100~1 200 m的石灰岩山地林下。该新种与越南楼梯草（E.vietnamense Q.Lin & L.D.Duan）接近,区别在于其拥有肉质茎,羽状脉,叶背面、苞片和小苞片被微硬毛。     

Effects of aqueous leaf extract of Bryophyllum pinnatum on guinea pig tracheal ring contractility

Aqueous leaf extract of Bryophyllum pinnatum Lam (Crassulaceae) is used as a cough remedy and for the prophylaxis of asthma. Since drugs used for the prophylaxis of asthma may be acting on airway smooth muscles, we investigated the effects of aqueous leaf extract of the plant on the contractile responses of isolated tracheal rings. Guinea pigs were grouped into non-sensitized, ovalbumin (OA)-sensitized, OA-sensitized but 200 mg/kg/day x 21 extract-treated, and OA-sensitized but 400 mg/kg/day x 21 extract-treated. The extract was administered orally. Tracheal rings obtained from the four groups were mounted in organ baths and used to test spasmolytic and antispasmodic effects of the extract on histamine or carbachol-induced contractions. Concentrations of 0.125-1.0 mg/ml of the extract did not relax histamine or carbachol-induced precontractions. The presence of 0.25-1.0 mg/ml of the extract in organ baths significantly reduced the maximal contractile responses (Emax) to cumulative concentrations of histamine or carbachol irrespective of the experimental group. pD2 values were significantly reduced for histamine and carbachol in rings obtained from 400 mg/kg/day x 21 extract-treated group. It is concluded that aqueous leaf extract of B. pinnatum possesses antispasmodic effects on the guinea pig tracheal rings. The results lend credence to the use of the extract for the prophylaxis of asthma in ethnomedicine.Keywords: Bryophyllum pinnatum; Tracheal rings; Anti-asthmatic; Antispasmodic; Herbal medicine.