岸滩粪便污染指示菌来源与影响因素研究进展

粪便污染指示菌(Fecal Indicator Bacteria,FIB),如大肠杆菌、肠球菌和耐热大肠菌等是用于指示水体中污染程度的微生物,但近年来的研究表明岸滩逐步成为FIB的重要储存库。微生物源示踪技术(MicrobialSourceTracking,MST)等方法被广泛应用于溯源岸滩FIB污染,但FIB进入岸滩环境后的生消机制尚不明确,因此影响FIB在岸滩上生存、消亡的各类因素仍是目前研究的热点。基于此,本文综述了岸滩生态系统中FIB的来源,同时结合国内外研究进展分析了影响FIB生存的非生物因素、生物因素及间隙流动等其他影响因素,并针对岸滩环境中FIB对人体健康的潜在风险提出相关建议,以期降低游客的患病风险,保障公共健康安全。     

Comparison of the physical properties of two Green Turtle (Chelonia mydas) nesting beaches (Akyatan and Samandağ) in the eastern Mediterranean (Reptilia: Cheloniidae)

The physical properities of sea turtle nesting beaches may strongly influence embryo development and hence conservation planning. In this study, we compared the characteristics of two nesting beaches of Green Turtles, Chelonia mydas, at Akyatan and Samanda? in southern Turkey. A total of 48 sand samples from 48 nests was examined and compared in respect to moisture content (M), temperature (TT), electrical conductivity (EC), salinity (S), total dissolved solution (TDS), pH, air ratio (AR), sand grain size together with distance from sea (DFS), depth (ND), incubation period (ID) and hatching success. Significant differences between the two areas were found in nest chamber moisture, conductivity, salinity, total dissolved solution and sand grain size. In a principal component analysis (PCA), the first component explained 45.1% of the variability and was dominated by the effects of the TDS, EC, S, pH and M. The second component explained 24.2 % of the variation and was dominated by the contributions of the TT, ID and ND. This is evidence that moisture plays a more important role than thermal properties in differentiating between the two beaches.     

Hand-operated box sampler for shallow water

The construction and operation of a hand-operated box sampler is described. The sampler covers an area of 25 × 25 cm and penetrates into the sediment to the depth of 15 cm. It was successfully operated on a sandy bottom, and on sand mixed with gravel up to a water depth of 1 meter.IAEC, Yavne 70600, Israel     

不同土壤-南天竹系统的土壤酶活性分异

石灰岩退化生态系统的恢复离不开土壤基质的改善。采用盆栽法,研究了生长在黑色石灰土、紫色土、黄壤3种不同土壤类型中的南天竹土壤酶活性的情况。试验表明:淀粉酶、碱性磷酸酶、天门冬酰胺酶的活性均表现出黑色石灰土>紫色土>黄壤,三者之间差异显著(p<0.05)。而脲酶、多酚氧化酶和过氧化物酶活性则是紫色土>黑色石灰土>黄壤,三者之间差异也达到显著水平(p<0.05)。土壤理化性质与土壤酶活性的相关分析说明土壤pH和全磷(P)对土壤酶的活性影响不大,而不同土壤类型中的全氮(N)和土壤含水率与部分土壤酶活性呈显著相关。不同土壤类型的土壤酶相关性表现各异。     

关于厦门的紫水鸡

19世纪中叶,英国鸟类学家Robert Swinhoe曾两次报道紫水鸡(Porphyrio porphyrio)在福建厦门的记录:当他本人第一次看到1只饲养在他人笼舍中的个体时,即判定它肯定不是P.poliocephalus[Latham,1801]而有可能是P.smaragdinus[Temminck,1827]^[1];两年后,当Swinhoe得到1只活体时,他认为该鸟应当是P.smaragdinus之下的一个亚种,同时,考虑到该鸟在形态上与P.smaragdinus略有差异,Swinhoe又"试探性地"将它命名为Porphyrio coelestis sp.nov.^[2]。无论Swinhoe当年的分类意见得当与否,他的这两次记录,都应当是发表于正式学术刊物上论证紫水鸡在中国有见的最初记录。     

Diphosphonucleotide phosphatase/phosphodiesterase (PPD1) from yellow lupin (Lupinus luteus L.) contains an iron-manganese center

Yellow lupin diphosphonucleotide phosphatase/phosphodiesterase (PPD1) represents a novel group of enzymes. Here we report that it possesses one iron atom and one manganese atom (1:1 molar ratio) per subunit. The enzyme exhibits visible absorption maximum at ∼530 nm. Prolonged oxidation of PPD1 leads to loss of the charge-transfer band and catalytic activity, whereas after reduction PPD1 remains active. Replacement of conserved amino-acid residues coordinating metals results in the loss of enzymatic activity. Despite low amino-acid sequence homology of PPD1 to well-characterized ∼55-kDa purple acid phosphatases, their overall fold, topology of active center and metal content are highly similar.     

The primary production of phytoplankton in the restored Maltañski Reservoir in Poland

Patterns in composition, abundance and diversity of the annelid fauna (Polychaeta and Oligochaeta) in 22 sandy beaches in Iceland were explored. The effect of exposure on annelid distribution was studied. A total of 5651 annelids were recorded from 160 core samples. Oligochaetes (chiefly Tubificidae) dominated the annelid assemblage whereas polychaetes represented a minor fraction. Polychaetes were relatively more abundant in exposed than in sheltered beaches, contrary to oligochaetes. Meiofaunal polychaete species were also more abundant in exposed than in sheltered beaches. Southwest beaches seemed more diverse in annelid species than northern ones. Annelid diversity did not differ between sheltered and exposed sites, but higher diversity was attained in fine sands at sheltered areas. Cluster analysis revealed large differences between beaches in the annelid community composition. The general patterns found suggest that beach exposure is a major factor conditioning macro- and meiofaunal polychaete and oligochaete distribution along the Icelandic coast.     

Disruption of a specific molecular interaction with a bound lipid affects the thermal stability of the purple bacterial reaction centre

Relatively little is known about the functions of specific molecular interactions between membrane proteins and membrane lipids. The structural and functional consequences of disrupting a previously identified interaction between a molecule of the diacidic lipid cardiolipin and the purple bacterial reaction centre were examined. Mutagenesis of a highly conserved arginine (M267) that is responsible for binding the head-group of the cardiolipin (to leucine) did not affect the rate of photosynthetic growth, the functional properties of the reaction centre, or the X-ray crystal structure of the complex (determined to a resolution of 2.8 Å). However, the thermal stability of the protein was compromised by this mutation, part of the reaction centre population showing an approximately 5 °C decrease in melting temperature in response to the arginine to leucine mutation. The crystallised mutant reaction centre also no longer bound detectable amounts of cardiolipin at this site. Taken together, these observations suggest that this particular protein-lipid interaction contributes to the thermal stability of the complex, at least when in detergent micelles. These findings are discussed in the light of proposals concerning the unfolding processes that occur when membrane proteins are heated, and we propose that one function of the cardiolipin is to stabilise the interaction between adjacent membrane-spanning α-helices in a region where there are no direct protein-protein interactions.     

Latitudinal patterns in abundance and life-history traits of the mole crab Emerita brasiliensis on South American sandy beaches

Demographic and life‐history attributes of the mole crab Emerita brasiliensis were analysed along 2700 km of the Atlantic coast of South America, including sandy beaches at the southernmost limit (Uruguay) and at the core of its geographical range (Brazil). Population features varied markedly within this range and exhibited systematic geographical patterns of variation. Abundance significantly increased from temperate to subtropical beaches, and the same held true for the asymptotic weight of males. Conversely, length at maturity and asymptotic weight of females increased from subtropical to temperate beaches, being inversely related to sea water temperature. Macroecological patterns in abundance and body weight showed the first large‐scale evidence of scaling of population density to body size for a sandy beach population. Mortality rates (both sexes) followed a nonlinear increase from low‐density temperate beaches to high‐density subtropical beaches. The effect of habitat quality and availability could explain discontinuities in the species distribution within its range, and also differential responses in life‐history attributes at a local scale. Asymmetries and converse latitudinal trends between sexes suggest that there is not a single general factor determining large‐scale patterns in life‐history traits of this species. Our results reinforce the view that density‐dependent and environmental factors operating together regulate sandy beach populations. The need to develop macroecological studies in sandy beach ecology is highlighted, as knowledge acquired from local to large spatial scales throws light on population structure and regulation mechanisms.     

紫甘薯花色苷色素的抑菌作用研究

本文研究了紫甘薯花色苷色素抑制大肠杆菌、金黄色葡萄球菌、啤酒酵母和黑曲霉的作用及机理。结果表明：紫甘薯花色苷色素对大肠杆菌及金黄色葡萄球菌均有抑制作用, 并与其浓度呈正相关, 而对啤酒酵母和黑曲霉无抑制作用。透射电镜观察和大肠杆菌生长曲线表明, 该色素的抑菌作用可能是通过增强细胞膜的通透性, 使细胞异常生长, 抑制对数生长期的细胞分裂, 使细胞质稀薄、细胞解体。SDS-PAGE 分析表明, 紫甘薯花色苷对大肠杆菌蛋白表达影响不明显, 未见特征性条带的消失, 仅对部分蛋白质合成量有影响。