Sesquiterpenes from Porella species

The Porella liverworts contain abundant sesquiterpenes. ent-Biocyclogermacrene, three ent-aromadendrenes, a unique hydrocarbon, α-pinguisene and two drimane type sesquiterpenes were obtained together with the intensly pungent component, tadeonal, from P. vernicosa and P. gracillima. P. macroloba contained the same sesquiterpenes except for the absence of ent-bicyclogermacrene and the ent-aromadendrenes. The fragrant odor of P. perrottetiana was composed of α-pinene and camphor.     

The Identification and Isolation of Steroidal Saponin from Dioscorea gracillima Miq.

Two trisaecharides of diosgenin (A, B) had been isolated from the rhizome of Dioseorea gracillima Maq. (collected from Jiangsi, Lu Shan). By means of acetylafion, acid hydrolysis, IR, MS and 13C-NMR etc. saponin A and saponin B were identifieated as dioscin and gracillin, respectively. Its yieldingratio is 3:1 (A:B).     

长江口夏季浮游植物群落与环境因子的典范对应分析

于2004年8月28日至9月6日在长江口水域进行了水文、化学和生物的综合嵌套式外业调查,应用CANOCO4.0软件对获得的浮游植物物种数据和环境因子数据进行了典范对应分析(CCA),并作出了物种、样点分布与环境因子关系的二维排序图。结果表明,长江水入海所带来的泥沙及其形成的营养盐梯度差异是影响这一区域物种分布格局最重要的因素。根据环境因子与排序轴的相关系数,影响这一海区浮游植物分布的主要环境因子依次为透明度、硝酸盐和硅酸盐。主要浮游植物优势种中肋骨条藻(Skeletonema costatum)和细长翼鼻状藻(Proboscia alata f. gracillima)的分布和硝酸盐以及盐度、浊度密切相关,中肋骨条藻适合在低盐度高浊度高硝酸盐浓度的河口水域生存,而细长翼鼻状藻则分布于高盐度高透明度低硝酸盐浓度的开阔海。排序揭示了浮游植物物种对于生态环境的需求以及它们在不同资源维上的生态分化现象。     

Some New Taxa of Charophyta in China

The authors examined specimens collected from Beijing, Hebei Province and North-east China. Two new species, one variety and five new records of the Characeae from China are reported in this paper. They are Nitella nenjiangensis sp. nov., Chara vertillibracteata sp. nov., C. globularis Thuiller var. beijingensis var. nov., Nitella axillaris Braun, N. crispa Imah., N. gracillima Allan, N. pseudoflabellata var. imperialis T. F. A., Chara arru-densis Mendes.     

纤细薯蓣甾体皂甙的分离鉴定

从江西庐山采集的纤细薯蓣根茎中分到两个三糖皂甙(A,B),通过乙酰化、酸水解、红外、质谱和碳谱等鉴定,皂甙 A 是薯蓣皂甙(dioscin),皂甙 B 是纤细皂甙(gracillin),二者得率之比约为3:1。     

Nutrient absorption,storage and remobilization in octopus vulgaris

Average absorption and conversion to ¹⁴CO₂for free leucine included in a meal were 96% and 30% after 24 h. The values for glucose were 98% and 48% and for palmitate 46% and 12.5%. Muscle was the major repository of leucine (38% of the total ingested) and glucose (44%), but the digestive gland contained most of the palmitate (20%).

During normal feeding ¹⁴CO₂ production from octopuses given leucine dropped to low stable levels after only 2 days, those given glucose required 4 to 5, but palmitate apparently did not enter a stable reserve. Fasting increased the release of ¹⁴CO₂ from octopuses given palmitate and leucine, but glucose animals showed little change. A 5‐fold increase in ¹⁴CO₂ production during forced exercise after fasting by octopuses given glucose may indicate increased carbohydrate catabolism. Reduced ¹⁴CO₂production in exercise after other substrates is consistent with this, suggesting muscle carbohydrate reserves may be exclusively for locomotion.

A comparison of nutrient uptake, catabolism and growth suggests that lipids are the limiting nutrient for octopuses on a crab diet.