The bio‐surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation

Methyl‐mannosylerythritol lipid (MEL), a new sugar esterified lipid synthesized by Pseudozyma aphidis, was assessed for its functionality in modulating rumen fermentation and microbiota toward more propionate and less methane production. A pure culture study using rumen representatives showed that MEL selectively inhibited the growth of most Gram‐positive bacteria including Streptococcus bovis, ruminococci, and Fibrobacter succinogenes, but not Gram‐negative bacteria such as Megasphaera elsdenii, Succinivibrio dextrinosolvens, and Selenomonas ruminantium. A batch culture study revealed that MEL significantly decreased methane production in a dose‐dependent manner with accumulation of hydrogen, while propionate production was enhanced. A continuous culture (Rusitec) study confirmed all of these changes. A feeding study revealed that sheep fed a MEL diet showed an increased proportion of propionate, while proportions of acetate and butyrate were decreased without affecting total VFA level. These changes disappeared after cessation of MEL feeding. Based on these results, dietary application of MEL can favorably modify rumen fermentation in terms of the efficiency of dietary energy utilization.     

Importance of bringing dogs in contact with children during their socialization period for better behavior

Much attention has been given to the role that dogs play in the social, physical, and psychological development of children. Furthermore, dogs are now playing a new important role in animal-assisted education (AAE). However, some dogs have difficulty getting along with children. The aim of this study was to demonstrate how dogs' contact with children during and after their socialization period influenced their responses toward children. In total, 31 pet dogs were divided into three groups. Group 1 dogs had been in contact with children during the canine socialization period (between 3 and 12 weeks of age); Group 2 dogs had been in contact with children after this socialization period; Group 3 dogs seldom had contact with children. As soon as a child entered the room, the dog was presented three stimuli by the child over the course of several intervals. The dogs' responses were evaluated by analyzing behavior and heart rates. The dogs that had been in contact with children during their socialization period did not show aggressive behavior or excited behavior toward the child in our test. Moreover, their heart rates were significantly decreased even during the last stimulus, which involved the child running around the dog while calling its name. This study suggested that the dogs having contact with children during socialization period might not show inappropriate responses toward children and could be suitable for taking part in AAE.     

The evaluation of autonomic nervous system activation during learning in rhesus macaques with the analysis of the heart rate variability

The aims of this study were to measure the activity of the autonomic nervous system using heart rate variability (HRV) during learning tasks and to clarify the relationship between learning to overcome a difficult situation and the autonomic nervous system in monkeys. Two young male monkeys (Macaca mulatta) were given simple discrimination learning tasks (DL) and delayed matching to samples tasks (DMTS); Holter-type electrocardiography was done, and HRV was measured. We defined the frequency bands of HRV in rhesus macaques; the low frequency (LF) was 0.01-0.15 Hz, and the high frequency (HF) was 0.15-0.50 Hz. Based on these frequency bands, the LF/HF ratios during learning tasks were analyzed, and a significant increase in the ratio was found during the tasks. The variances in the HF differed between the DL and DMTS tasks; during DMTS tasks, HF variances had a tendency to increase. Our results indicate that increased sympathetic activity accompanied learning and suggest that the parasympathetic nervous system plays a key role during learning, particularly when difficult tasks are being learned.     

Production of refractory dissolved organic matter by bacteria

Most of the oceanic reservoir of dissolved organic matter (DOM) is of marine origin and is resistant to microbial oxidation, but little is known about the mechanisms of its formation. In a laboratory study, natural assemblages of marine bacteria rapidly (in <48 hours) utilized labile compounds (glucose, glutamate) and produced refractory DOM that persisted for more than a year. Only 10 to 15% of the bacterially derived DOM was identified as hydrolyzable amino acids and sugars, a feature consistent with marine DOM. These results suggest that microbial processes alter the molecular structure of DOM, making it resistant to further degradation and thereby preserving fixed carbon in the ocean.     

Nitrate adsorption in some andisols developed under different moisture conditions

Nitrate leaching from agricultural lands is one of the most critical problems related to both environmental quality and human health. Although in many studies surfacecharge properties of and nitrate adsorption in soils have been analyzed in tropical and subtropical regions, fewer studies have been conducted on the nitrateretention properties of allo phanic Andisols. The objectives of the present study were to examine the potential nitrate adsorption capacity and the factors affecting nitrate retention in topsoils and subsoils of three Andisols Tokaachi, Hokkaido. Nitrate adsorption at pH 6.0 was found to be low or negligible even in the subsoil of a Haplic Wet Andisol (Melanaquands), despite the high clay content, Nitrate adsorption maxima calculated from the Langmuir equation were higher in the lower horizons of a Haplic Andisol (Melanudands) and a Lowhumic Andisol (Hap ludands), which were developed under moderate to moderately dry moisture conditions and displayed a high allophane content and a low total carbon content. The nitrate adsorption of the aliophanic Andisols was much higher than that reported from other studies conducted in Ultisols and Oxisols, which are rich in iron oxides. The potential capacity to adsorb nitrates and retard nitrate movement should be taken into account in predicting the fate of nitrate in soils and the consequent mitigation of groundwater contamination.     

Isolation and characterization of a phenolic antioxidant from the Pacific oyster (Crassostrea gigas)

Using an oxygen radical absorbance capacity (ORAC) assay, antioxidant activity was detected in the ethanol extract of the Pacific oyster, which was purified by sequential extraction with organic solvents. The ethyl acetate fraction showed the strongest antioxidant activity and was further purified, yielding a single compound [as assessed by thin-layer chromatography (TLC) and reverse-phase high-performance liquid chromatography (HPLC)]. This compound was identified as 3,5-dihydroxy-4-methoxybenzyl alcohol on the basis of (1)H and (13)C nuclear magnetic resonance (NMR), heteronuclear multiple-bond correlation (HMBC), and electrospray ionization-mass spectrometry (ESI-MS) spectral analyses, a conclusion that was confirmed by chemical synthesis. The concentration of the compound was 6.7 mg/100 g of whole oyster meat wet weight. This amphiphilic antioxidant retarded the copper-mediated oxidation of low-density lipoproteins (LDLs) and the generation of thiobarbituric acid reactive substances. Furthermore, the compound showed substantial antioxidant activity using the ORAC and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays compared to natural antioxidants. Although the same compound was previously found in brown algae, its presence in other organisms and antioxidant activity are reported here for the first time.     

孟加拉东北地区棕榈藤企业——现状和经济效益

通过探索性调查,本文采用多级随机抽样的方法对孟加拉东北部地区棕榈藤企业的地区贸易模式、经济效益和销售体系进行了评估。根据总投资额,企业分为大型、小型和中型。多数企业家(36.67%)的年龄在30-40或40-50之间。在小型企业中,高学历企业主的比例最低,只有3.33%;而大型企业中的高学历企业主占13.33%成熟企业者。多数企业为小型企业,为46.67%;60%的工人为熟练工,只有40%为非熟练工。经调查,这些企业生产了14种藤产品,共为23个不同尺寸,其中包括沙发(尺寸为45cm×45cm、50cm×50cm和55cm×55cm),餐桌椅系列(4把椅子和一张桌子,或6把椅子和一张桌子)、床(1cm×2cm、1.3 cm×2.3 cm和1.5 cm×2.3 cm)、椅子(45cm×45cm和50cm×50cm)、摇椅(大、中、小)、隔板、花瓶、镜框、手工艺品、台灯、手杖、茶桌等。在大型企业中,生产最多的是椅子(45cm×45cm),而中小型企业的产品中以椅子(50cm×50cm)和手工品居多。在这3种企业中,床(1.5cm×2.3cm)的生产量最少。在大型企业中,总净效益为185 659塔卡,效益成本比为1:18,均为最高。在这3种企业中,大型企业的利润最高。     

Changes in petiole hydraulic properties and leaf water flow in birch and oak saplings in a CO2-enriched atmosphere

Water relations in woody species are intimately related to xylem hydraulic properties. High CO(2) concentrations ([CO(2)]) generally decrease transpiration and stomatal conductance (g(s)), but there is little information about the effect of atmospheric [CO(2)] on xylem hydraulic properties. To determine the relationship between water flow and hydraulic structure at high [CO(2)], we investigated responses of sun and shade leaves of 4-year-old saplings of diffuse-porous Betula maximowicziana Regel and ring-porous Quercus mongolica Fisch. ex Ledeb. ssp. crispula (Blume) Menitsky grown on fertile brown forest soil or infertile volcanic ash soil and exposed to 500 micromol CO(2) mol(-1) for 3 years. Regardless of species and soil type, elevated [CO(2)] consistently decreased water flow (i.e., g(s) and leaf-specific hydraulic conductivity) and total vessel area of the petiole in sun leaves; however, it had no effect on these parameters in shade leaves, perhaps because g(s) of shade leaves was already low. Changes in water flow at elevated [CO(2)] were associated with changes in petiole hydraulic properties.     

孟加拉国Bhanugach西部保育林用地类型变化(英文)

应用遥感和地理信息系统调查了孟加拉国Sylhet林业分局所辖的Bhanugach西部保育林从1988年到2006年间用地类型的变化。应用了监督和非监督两种方法,用全球定位系统搜集了地面控制点。地理信息系统软件制成地图。结果表明,植被覆盖从1988年的1826hm2大幅地降低到1996年的1714.85hm2,随着协同管理措施的实施,植被覆盖自1996年后逐年增长到2006年的1847.83hm2。在没有其他类型的用地转变成裸地的情况下,裸地变化与植被覆盖间成反比。18年间水体面积从1988年的307.67hm2增加到1996年379.53hm2,96-97年间略有下降,1997年以后直到2006年基本保持不变。本文还提出了将遥感技术和地理信息系统应用于用地类型变化及地理信息系统数据库创建的一些建议。