Latex proteins from the plant Calotropis procera are partially digested upon in vitro enzymatic action and are not immunologically detected in fecal material

Soluble proteins from the latex of Calotropis procera (LP) were investigated in vitro and in vivo for digestibility as the latex has previously been shown to produce considerable toxic effects on animals. The latex is also an important biologically active compound that displays antiinflammatory and antidiarrhea properties. The proteins were digested by the action of trypsin, pepsin or chemotrypsin as revealed by gel filtration and SDS-PAGE analysis. Furthermore, the full LP digestion was easily achieved by protease treatment. Rabbit polyclonal antibodies raised against LP failed to detect cross-reactive molecules in fecal material of experimental rats following 35 consecutive days of LP consumption in water. Similar patterns of electrophoresis were observed for the negligible amounts of protein observed in the fecal extracts of control and test animals. No death or toxic effects were observed among animals. Taken together these results suggest that harmful and toxic effects on animals of the latex from C. procera are present in its rubber and low molecular weight fractions rather than its protein content.     

Floral induction in Eucalyptus nitens

Eucalyptus nitens (Deane & Maiden) Maiden takes at least five years to initiate flower buds from seed and is an infrequent and light flowerer. Because this behavior constitutes a major impediment to breeding programs, we examined the mechanisms controlling floral induction in E. nitens, with the long-term aim of reducing generation time and increasing seed yield. Application of paclobutrazol reduced the concentration of endogenous gibberellic acid (GA) in apical tissue and enhanced the reproductive activity of grafted trees maintained outside over winter in Canberra, Australia. Grafts maintained in a warm greenhouse over winter did not produce flower buds, despite the paclobutrazol-induced reduction in GA concentration of the apical tissue. Exposing untreated grafts, which had been maintained over winter in a warm greenhouse, to low temperature the following spring reduced growth but did not induce flower bud production. Addition of GA(3) to paclobutrazol-treated grafts reduced the effect of paclobutrazol on reproductive activity.     

Nutritional value of a highly digestible sorghum cultivar for meat-type chickens

The nutritional value of a newly discovered sorghum mutant cultivar (P851171), with high in vitro protein digestibility, was compared to those of corn and two normal sorghums (P721N and 611Y) in two chick feeding trials. Although 8-20 day protein efficiency ratios and net protein ratios of all three sorghums were inferior to those of corn, P851171 and 611Y had markedly greater mean true amino acid digestibilities (TAAD) than either corn or P721N. In a subsequent 42-day experiment, all three sorghums supported weight gains equal to those of the corn-fed chicks. Feeding suboptimal levels of dietary protein resulted in reduced weight gains and no observed benefits of P851171 or 611Y. Furthermore, chicks fed P851171 exhibited poorer feed/gain values as compared to those fed the other cereals. It is possible that the starch content/carbohydrate profile of P851171 was inferior to that of the other sorghums, which offset its superior TAAD and resulted in poorer broiler performance.     

Characterization of antioxidants present in bitter tea (Ligustrum pedunculare)

The present study examined the antioxidants present in bitter tea (Ligustrum pedunculare). It was found that the crude glycoside fraction strongly protected human low-density lipoprotein (LDL) from oxidation. Further column chromatography led to purification of eight phenylethanoid or monoterpene glycosides: lipedoside A-I, lipedoside A-II, lipedoside B-I, lipedoside B-III, lipedoside B-V, lipedoside B-VI, osmanthuside B, and anatolioside. It was found that lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI were protective, whereas the other four compounds did not protect human LDL from Cu(2+)-medicated oxidation. Lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI also had a scavenging effect on 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), comparable to that of alpha-tocopherol. The inhibitory effect of these four phenylethanoid or monoterpene glycosides on oxidation of human LDL and alpha-tocopherol was dose-dependent at concentrations of 5-40 microM. The present results demonstrate that bitter tea as a beverage contains effective antioxidants that may have benefits similar to those of green tea in terms of antioxidant activity.     

New mosquito larvicidal tetranortriterpenoids from Turraea wakefieldii and Turraea floribunda

The crude methanol extracts of the root barks of Turraea wakefieldii and Turraea floribunda were found to show mosquito larvicidal activity against third-instar larvae of Anopheles gambiae sensu stricto. Four new limonoids comprising a vilasininoid 1 and three havanensinoids 2-4 were isolated from the chloroform fractions of the methanol extracts of T. wakefieldii and T. floribunda, respectively. The structures of the compounds were elucidated by NMR spectroscopy. Compounds 1, 2, and 4 had LD50 values of 7.1, 4.0, and 3.6 ppm, respectively, and were more potent than azadirachtin, which had an LD50 value of 57.1 ppm when tested against larvae of A. gambiae.     

水环境中噬菌蛭弧菌的分离鉴定

噬菌蛭弧菌为一类杆形、弧形或螺旋形的革兰阴性菌,可以寄生并裂解其他细菌。本试验以禽源大肠杆菌、沙门菌以及环境水体中分离的1株大肠杆菌为宿主菌,采用双层琼脂培养法成功地从环境水体中分离到3株噬菌蛭弧菌,分别命名为BDD、BDE、BDH。电镜观察证明菌体大小约0.33μm×0.78μm,单个弧形,一端有一根长鞭毛。基因序列分析表明,分离株与已发表的噬菌蛭弧菌属其他菌株16S rRNA基因序列的同源范围分别为96.0%~99.9%。通过对不同细菌的裂解试验证明,3个分离株对大肠杆菌、沙门菌、摩根摩根氏菌、变形杆菌和阴沟肠杆菌等均具有裂解作用,但对铜绿假单胞菌、鸭疫里默氏菌和金黄色葡萄球菌不敏感。