Chemical characterization of milk oligosaccharides of the island flying fox (Pteropus hypomelanus) (Chiroptera: Pteropodidae)

Although a considerable amount of information has accumulated about oligosaccharides in the milk and colostrum of representatives of various mammalian orders, nothing is so far known concerning these sugars in the milk of any bat species (order Chiroptera). In this study, we determined that the following oligosaccharides occur in milk of the island flying fox, Pteropus hypomelanus (Chiroptera: Pteropidae): Gal(α1–3)Gal(β1–4)Glc (isoglobotriose), Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (lacto‐N‐neotetraose), Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto‐N‐neohexaose) and Neu5Gc(α2–3)Gal(β1–4)Glc (3′‐NGc‐SL). However, lactose was found to be the dominant saccharide in this milk, as in most eutherian mammals. The biologic importance of oligosaccharides in Chiropteran milks warrants further study.     

气相色谱-质谱法测定小鼠血浆的尼古丁和可替宁

建立了一种同时测定小鼠血浆中尼古丁和可替宁含量的气相色谱-质谱方法.以二苯胺为内标,采用HPDB-225毛细管色谱柱(30 m×0.25 mm i.d.,膜厚0.25μm)和选择离子监测.该方法尼古丁和可替宁的线性范围均为40～1 000 ng/mL,线性相关系数分别为0.998 9和0.999 7,检出限均为2 ng/mL.平均回收率尼古丁为83.2%～94.6%,可替宁为79.3%～101.6%.该方法简便、特异、灵敏、重现性好.     

Enhancement of resistance to bacterial infection in rainbow trout, Oncorhynchus mykiss (Walbaum), by oral administration of bovine lactoferrin

Abstract Bovine lactoferrin was evaluated for its ability to enhance resistance of rainbow trout, Oncorhynchus mykiss (Walbaum), to infection with Vibrio anguillarum. Oral administration of lactoferrin (100 mg kg⁻¹) to fish daily for 3 days prior to an intraperitoneal challenge with V. anguillarum resulted in increased survival rates, and enhanced resistance against Streptococcus sp., although to a lesser extent. In lactoferrin-treated fish, an increase in phagocytic and chemiluminescent (CL) activities of pronephros cells against V. anguillarum was observed. The phagocytic and CL activities of cells against Streptococcus sp. were also significantly increased. However, no in vitro bactericidal activities of lactoferrin against V. anguillarum or Streptococcus sp. were observed. This suggests that the lactoferrin enhanced the resistance of the rainbow trout against bacterial infection through the activation of phagocytes.     

El Niño effects in the Palmyra Atoll region: oceanographic changes and bigeye tuna (Thunnus obesus) catch rate variability

A generalized additive model (GAM) was constructed to separate and quantify the effects of fishery‐based (operational) and oceanographic parameters on the bigeye tuna (Thunnus obesus) catch rates at Palmyra Atoll in the central Tropical Pacific. Bigeye catch, the number of hooks per set, and set location from 4884 longline sets spanning January 1994 to December 2003 were used with a temporally corresponding El Niño‐Southern Oscillation (ENSO) indicator built from sea surface height (SSH) data. Observations of environmental data combined with the results from the GAM indicated that there is an increase in bigeye catch rates corresponding to an increase in eastward advection during the winter months of El Niño events. A seasonal pattern with higher bigeye catch rates from December to April and a spatial pattern with higher rates to the northeast and northwest of the atoll were observed during this study period. It is hypothesized that the combination of the eastward advection of the warm pool coupled with vertical changes in temperature during the winter months of El Niño events increases the availability of bigeye tuna in this region. This increase in availability may be due to a change in exploitable population size, location, or both.     

基于3S的黄土高原北部土地沙化分析——以陕西省神木县为例

采用实地调查和遥感数据分析相结合的方式,分析黄土高原北部神木县的土地沙化变化趋势及社会背景因素,为草地沙化的有效遏制提供依据。结果表明,神木县的土地沙化呈“整体缩小局部扩展”趋势。1986-2004年,沙化土地面积减少了10%（750 km2）。土地沙化在地区间有很大差异,县西北部乡镇里沙化土地减少明显,而南部的黄土峁地区沙化土地有所增加。与社会统计资料对比分析后发现,耕地面积比例大、人均土地面积少的乡镇地区,土地沙化趋势明显。以上结果意味着农田利用对黄土峁地区土地沙化有很大影响,传统耕作方式的改变有助于遏制土地沙化。     

Bean husks as a supplemental fiber for ruminants: Potential use for activation of fibrolytic rumen bacteria to improve main forage digestion

This study evaluated the suitability of easily digested fiber sources as a supplemental fiber to improve overall fiber digestion in ruminants. First, the degradation of five fibrous feedstuffs and the stimulatory effects on rumen bacteria were examined in situ. Chickpea and lablab bean husks were selected for their potential use due to their large degradable fraction (> 94%), which had a stimulatory effect on fibrolytic rumen bacteria such as Fibrobacter succinogenes. Second, a possible improvement in the digestibility of rice straw diet by husk supplementation was monitored in vivo. Four dietary treatments comprising RS (rice straw and concentrate), CHM (RS supplemented with Myanmar chickpea husk), CHE (RS with Egyptian chickpea husk) and LH (RS with lablab bean husk) were allocated to four wethers. The digestibility of acid detergent fiber was 3.1–5.5% greater in CHM and LH than RS. Total volatile fatty acid concentration was higher in LH than other treatments. Acetate proportion was higher in LH than RS. Ruminal abundance of F. succinogenes was 1.3–1.5 times greater in CHM and LH than RS. These results suggest that bean husk supplementation, especially lablab bean husk, might improve the nutritive value of rice straw diet by stimulating fibrolytic bacteria.     

Differential safening activity of dymron and fenclorim on pretilachlor injury in rice seedlings in soil

The safening activity of dymron [1-(α,α-dimethylbenzyl)-3-( p -tolyl)urea] and fenclorim [4,6-dichloro-2-phenylpyrimidine] on the phytotoxic activity of pretilachlor [2-chloro-2',6'-diethyl- N- (2-propoxyethyl)acetanilide] on rice seedlings was examined in both water and soil culture. The safening activity of fenclorim in water culture was greater than that of dymron, whereas the activity of fenclorim in soil was lower than that of dymron. The fenclorim concentration in soil water was lower than that of dymron at all times when determined after the application at the same concentrations. The phytotoxic activity of pretilachlor and the safening activities of dymron and fenclorim were well correlated with the concentration of each in soil water but not with the amount in total soil. The adsorption of fenclorim on soil solids was greater than those of dymron and pretilachlor. It was suggested that both the phytotoxic activity of pretilachlor and the safening activities of dymron and fenclorim were dependent on their concentrations in soil water, which were primarily dominated by the adsorption on soil.     

Partial characterization of structure and function of a xylanase gene from the rumen hemicellulolytic bacterium Eubacterium ruminantium

A gene encoding for xylanase activity in the rumen hemicellulolytic bacterium Eubacterium ruminantium was cloned into pBR322 in Escherichia coli (E. coli ). The primary clone had a 5.7 kb insert produced by Eco RI partial digestion. Subcloning followed by sequencing allowed for the discovery that this enzyme has a glycosyl‐hydrolase family 10 catalytic domain with a family 9 carbohydrate binding module at C‐terminus and a region partially homologous to a family 22 carbohydrate binding module at N‐terminus. Cloned xylanase is specifically active against xylan and oligoxyloside to produce xylobiose and xylotriose, showing optimal pH and temperature at 7.0 and 50°C, respectively. Molecular size of the xylanase (91 kDa) was confirmed by zymogram analysis of the E. coli clone, which agreed with the predicted size from the DNA sequence. Functions of the two modules at C‐ and N‐termini were evaluated by using xylanase variants with and without the respective module and the C‐terminal module was found to be functional in binding to acid‐swollen cellulose and insoluble oat‐spelt xylan, whereas the N‐terminal module was inactive for binding them.