西沙石珊瑚共附生放线菌的分离培养及抗菌活性评价

【背景】珊瑚礁生态系统是海洋中一类极其重要的生态系统,健康珊瑚礁中丰富的共附生放线菌群体是珊瑚抵御各种致病菌的重要防线,因此,这类放线菌是寻找抗菌活性分子的重要资源,其药用潜力巨大。【目的】从西沙石珊瑚样品中分离共附生放线菌,并从中筛选具有良好抗菌活性的菌株。【方法】通过稀释涂布法分离珊瑚共附生放线菌,并根据16S rRNA基因序列构建系统发育树进行菌种鉴定;通过平板对峙法对放线菌进行抗菌活性筛选并确定目标菌株;将目标菌株涂布于不同氯化钠浓度的ISP2固体培养基上培养,测试其盐度耐受能力;通过平板对峙法对该菌株发酵产物的热稳定性和光稳定性进行测试;采用NanoPore和Illumina方法完成目标活性放线菌全基因组测序,并通过antiSMASH在线分析预测其次级代谢产物生物合成基因簇及其结构类型。【结果】从6份西沙石珊瑚样品中分离得到104株可培养放线菌,根据菌落形态和分离来源去重后对其中27株放线菌进行16S rRNA基因序列测序,通过序列比对和系统发育树分析将菌株初步鉴定为盐孢菌属(Salinispora)(25株)、链霉菌属(Streptomyces)(1株)和戈登菌属(Gord...     

河南淅川坑南遗址调查发现的石制品

河南淅川坑南遗址位于丹江口库区,丹江口库区是近年来旧石器考古发掘和研究的重点地区。2016年对坑南遗址发掘前,在周边调查发现旧石器时代石制品209件,石制品类型包括石核、石片、石叶和石器等。剥片方法有锤击法和砸击法。石器毛坯类型多为片状,少量为块状、砾石。石器修理方式以正向为主,其次为反向和复向。初步判断其时代最早能到旧石器时代中期。新发现对于探讨晚更新世南北旧石器过渡地带的特点,具有重要意义。     

植酸对月季切花瓶插寿命的影响

用0.13％和0.013％植酸对月季切花进行处理,探讨了植酸对月季切花瓶插寿命及衰老过程中一些生理生化指标的影响.结果表明,013％和0.013％植酸处理的切花,瓶插寿命分别延长了2.3 d和1.4d.植酸处理抑制了O-2含量的增加和POD活性的提高,从而减轻了O-2对植物细胞的伤害即抑制丙二醛含量增加,同时抑制了可溶...     

库尔勒香梨果实石细胞发育及其对果实肉质影响初探

采用植物解剖学方法对库尔勒香梨果实石细胞形成过程和分布状况进行观察研究,结果表明,库尔勒香梨果实中石细胞从化后15d开始形成,随着时间的推移石细胞的直径和密度逐渐增大,花后110d左右直径达到最大值,花后50d左右密度达到高峰．之后随着果实的增大与成熟度的提高,石细胞团的密度表现下降的趋势。石细胞的分布特点是石细胞团以近果心和近果皮处分布密度高,直径大,中层果肉中石细胞团密度低,直径小。与其它品种相比,成熟库尔勒香梨的行细胞团密度最低,含有较大石细胞的含量相对较少,肉质较细。     

萝卜硫素通过Nrf2信号通路对大鼠草酸钙肾结石形成的作用和机制研究

摘要 目的：探究萝卜硫素通过Nrf2信号通路对大鼠草酸钙肾结石形成的作用和机制。方法：选取7~8周龄Wistar健康雄性大鼠30只,随机分为空白对照组、模型组和药物干预组。空白对照组给予正常饮用水,标准饲料;模型组给予1%乙二醇饮用水+2%氯化铵2 mL/d灌胃,标准饲料;药物干预组给予1%乙二醇饮用水+2%氯化铵2 mL/d灌胃+0.2 mg萝卜硫素腹腔注射,标准饲料。灌胃给药均连续28天。于第29天收分别集各组大鼠24 h尿液及肾脏标本,使用全自动生化分析仪检测尿液中K⁺、Na⁺、Cl⁺、Ca²⁺、Mg²⁺、P⁵⁺、Fe²⁺含量,使用ELISA法测定尿液中丙二醛( malondialdehyde,MDA)与草酸水平,使用HE染色分析大鼠肾脏标本病理损伤情况,Von Kossa染色比较各组大鼠钙盐沉积情况,免疫组化法测定谷胱甘肽(glutathione,GSH)、核因子E₂相关因子2(nuclear factor erythroid-2 related factor 2,Nrf2)、8-羟基脱氧鸟苷(8-hydroxy-2 deoxyguanosine,8-OHDG)蛋白表达水平。结果：模型组大鼠尿液P⁵⁺、Ca²⁺、草酸、MDA含量显著高于空白对照组,HE染色示模型组肾小管较空白对照组变性严重,Von Kossa染色结果显示模型组钙盐沉积较空白对照组明显增多,模型组GSH、Nrf2免疫组化评分显著低于空白对照组,8-OHdG显著高于空白对照组,差异均有统计学意义（P＜0.05）;药物干预组大鼠尿液P⁵⁺、Ca²⁺、草酸、MDA含量显著低于模型组,HE染色、Von Kossa染色显示肾小管较模型组损伤减轻,钙盐沉积较模型组减轻,免疫组化显示GSH、Nrf2蛋白表达显著高于模型组,8-OHdG显著低于空白对照组,差异均有统计学意义（P＜0.05）。结论：萝卜硫素对大鼠肾小管具有抗氧化损伤作用,可降低草酸钙晶体的释放,抑制草酸钙结石的形成,该作用可能是通过激活Nrf2蛋白及其下游信号通路实现的。     

A Pinus cembra L. tree-ring record for late spring to late summer temperature in the Rhaetian Alps,Italy

Ongoing climate change strongly affects high-elevation environments in the European Alps, influencing the cryosphere and the biosphere and causing widespread retreat of glaciers and changes in biomes. Nevertheless, high-elevation areas often lack long meteorological series, and global datasets cannot represent local variations well. Thus, proxy data, such as tree rings, provide information on past climatic variations from these remote sites. Although maximum latewood density (MXD) chronologies provide better temperature information than those based on tree-ring width (TRW), MXD series from the European Alps are lacking. To derive high-quality temperature information for the Rhaetian Alps, Pinus cembra L. trees sampled at approximately 2000 m a.s.l. were used to build one MXD chronology spanning from 1647 to 2015. The MXD data were significantly and highly correlated with seasonal May-September mean temperatures. The MXD chronology showed a generally positive trend since the middle of the 19^th century, interrupted by short phases of climatic deterioration in the beginning of the 20^th century and in the 1970s, conforming with the temperature trends. Our results underline the potential for using Pinus cembra L. MXD to reconstruct mean temperature variations, especially during the onset and latter part of the growing season, providing additional information on parts of the growing season not inferred from TRW. Future studies on MXD for this species will increase the availability of temporal and spatial data, allowing detailed climate reconstructions.     

1-MCP-β-环糊精对香石竹切花保鲜作用的研究

对香石竹切花（Dianthus caryophyllus L．）用不同体积浓度的1-MCP-β-环糊精溶液处理不同的时间,观察其外观形态品质和生理生化指标,得知以50mg／L的1-MCP-β-环糊精溶液在7m^3的密闭体系中处理8h效果最佳。能极大提高香石竹切花的观赏价值,减少萎蔫程度,延缓开放,延迟香石竹切花叶片质膜相对透性下降,并对叶片叶绿素含量变化有一定的影响。     

Patterns of larval release in the Florida stone crab, Menippe mercenaria

Larval release patterns in brachyuran crabs are often synchronized with environmental cycles. While previous studies have focused extensively on supratidal and intertidal taxa, there have been relatively few investigations of subtidal species. This study examined patterns of larval release by the Florida stone crab, Menippe mercenaria, from three different tidal regimes. Ovigerous stone crabs were collected from Sebastian Inlet on the east coast of Florida, Tampa Bay on the west coast of Florida, and the Florida Keys. Patterns of larval release were monitored in the laboratory in relation to local tidal and diel cycles. Results showed a significant diel pattern in initiation of hatching by crabs from each of three study areas. Larval release consistently occurred during the diurnal phase despite the maintenance of females in constant laboratory conditions for up to 96 h prior to hatching. This implies that release may be controlled by a circadian clock. Patterns of release by stone crabs in relation to tidal cycle were more variable. Larval release by females from populations near Tampa Bay and Sebastian Inlet were not synchronized with the tides, whereas females collected from the Florida Keys exhibited a pattern that was strongly related to tidal cycle. These results may be explained by differences in tidal amplitude at the three sampling locations.     

Production and optimization of thermophilic alkaline protease in solid-state fermentation by <Emphasis Type="Italic">Streptomyces</Emphasis> sp. CN902

The purpose of the present research is to study the production of thermophilic alkaline protease by a local isolate, Streptomyces sp. CN902, under solid state fermentation (SSF). Optimum SSF parameters for enzyme production have been determined. Various locally available agro-industrial residues have been screened individually or as mixtures for alkaline protease production in SSF. The combination of wheat bran (WB) with chopped date stones (CDS) (5:5) proved to be an efficient mixture for protease production as it gave the highest enzyme activity (90.50 U g⁻¹) when compared to individual WB (74.50 U g⁻¹) or CDS (69.50 U g⁻¹) substrates. This mixed solid substrate was used for the production of protease from Streptomyces sp. CN902 under SSF. Maximal protease production (220.50 U g⁻¹) was obtained with an initial moisture content of 60%, an inoculum level of 1 × 10⁸ (spore g⁻¹ substrate) when incubated at 45°C for 5 days. Supplementation of WB and CDS mixtures with yeast extract as a nitrogen source further increased protease production to 245.50 U g⁻¹ under SSF. Our data demonstrated the usefulness of solid-state fermentation in the production of alkaline protease using WB and CDS mixtures as substrate. Moreover, this approach offered significant benefits due to abundant agro-industrial substrate availability and cheaper cost.