The morphological and molecular analyses of a new South American urban tardigrade offer new insights on the biological meaning of the Macrobiotus hufelandi group of species (Tardigrada: Macrobiotidae)

Worldwide knowledge of tardigrade fauna is still limited, and many areas such as South America are not well studied. The collection of new substrates in Argentinean urban areas provided an opportunity to describe the new tardigrade species Macrobiotus kristenseni sp. nov. This species has been studied with an integrative taxonomic approach, analysing its morphology by light and scanning electron microscopy, and considering two genes (cox1 and 18S rRNA) for DNA barcoding and phylogenetic purposes. The species belongs to the Macrobiotus hufelandi group of species, and it is characterized by egg processes in the shape of elongated cones with truncated and enlarged apexes, and by a high genetic distance with respect to closely related species (cox1: 18.2–33.4%). Morphological and molecular data show that the Macrobiotus hufelandi group of species has to be considered a true biological entity; one of the more widespread tardigrade lineages in continental environments. http://www.zoobank.org/urn:lsid:zoobank.org:pub:2CA51ABA-5570-4AFB-8182-CE499D97B0F1     

Genus Baseodiscus (Nemertea: Heteronemertea): Molecular identification of a new species in a phylogenetic context

A new heteronemertean, Baseodiscus jonasii sp. nov., is described from Guadalcanal, Solomon Islands. It resembles B. delineatus in inner morphology but can be distinguished from this species by its different colour pattern and differences in the nucleotide sequence of the mitochondrial 16S rRNA gene. The monophyletic status of the genus is investigated by reconstructing the phylogeny of six specimens from four species assigned to this genus, together with 22 specimens from nine other heteronemertean genera, using parsimony and Bayesian analysis. The results imply that Baseodiscus is a monophyletic group while several other heteronemertean genera are non‐monophyletic.     

温度、光照和磷质量浓度对小环藻、大型溞和金鱼藻共培养的影响

为了研究温度、光照和磷质量浓度对生物操纵效果的影响,选用小环藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型水生植物的代表种,建立不同磷质量浓度(0.05、0.1、0.5、2mg/L)的水生微宇宙模型,研究不同温度梯度(15、20、25、30℃)、不同光照强度(1000、2600、4200、5800lx)及不同光暗比(10∶14、12∶12、14∶10、16∶8)条件下浮游动物和沉水植物的控藻效果.结果表明:磷质量浓度为0.05~0.5mg/L、温度在20~25℃时,大型溞和金鱼藻生长较好,对小环藻有明显的抑制作用;磷质量浓度为0.05~0.5 mg/L、光照强度在1000~4200lx时,大型溞和金鱼藻对小环藻有明显的抑制作用;强光(5800lx)有利于小环藻、金鱼藻的生长,但对大型溞有抑制;磷质量浓度为0.05~0.5mg·L-1,光暗比为14h∶10h时,大型溞和金鱼藻生长最好,可以达到很好的抑藻效果;当磷质量浓度相同时,温度30℃、光照5800lx时,培养液中氮磷去除率最高.     

NTG对侧耳的诱变效应

采用正交试验设计以菌落直径为指标研究了NTG对侧耳8405的诱变效应.实验结果表明:当NTG的最终浓度为300μg/mL,处理前孢子先培养14h,于24℃黑暗条件下处理40min时,突变率和正变率高,变异幅度大.     

假单胞菌DM11的二氯甲烷脱卤素酶研究──Ⅱ．动力学性质和抑制剂

对来自假单胞菌（Ｐｓｅｕｄｏｍｏｎａｓｓｐ．）ＤＭ１１菌株的二氯甲烷脱卤素酶（简称ＤＭ１１脱卤素酶）的动力学性质和抑制剂进行了研究。用１／Ｖ对１／［ｓ］作图法，测出ＤＭ１１脱卤素酶以ＣＨ２Ｃｌ２、ＣＨ２Ｂｒ２、ＣＨ２Ｉ２、ＣｌＣＨ２Ｂｒ和ＣｌＣＨ２Ｉ等５种化合物为底物时的Ｋｍ值分别是６７、２０、５５、７和９μｍｏｌ／Ｌ，比活力分别是７７．８、１２３．３、７８．８、５６．１和６０．３ｍｋａｔ／ｋｇ蛋白。测定了１４种抑制剂对ＤＭ１１脱卤素酶的５０％抑制浓度（Ｉ５０）。甲基谷胱甘肽（ＧＳＣＨ３）是ＤＭ１１脱卤素酶的竞争性抑制剂，四硝基甲烷（ＴＮＭ）是非竞争性抑制剂，当甲基谷胱甘肽和四硝基甲烷与ＤＭ１１脱卤素酶一起保温时，甲基谷胱甘肽对酶有保护作用。     

一种游仆虫无性生殖周期中大核及其DNA含量的变化

应用光学显微镜、显微光度计和定量细胞化学技术研究了一种游仆虫无性生殖周期中大核及其 DNA 含量的变化特征,获得如下结果:(1)游仆虫细胞周期分成 G_1期、S 期和 D 期,各个时期在整个细胞周期中所占的时间速率分别为36%、59%和5%。(2)游仆虫细胞周期中,G_1期大核迅速增大,但此时大核无 DNA 合成现象,DNA 分布密度随大核增大而降低;S 期大核前期增大,此后变小,大核 DNA 含量连续增加,大核 DNA 分布密度也随着增高。8期结束后,大核 DNA 含量相当于 G_1大核的两倍;D期大核又显著增大,DNA 分布密度稍高于 G_1期大核的水平。(3)由游仆虫孚尔根反应大核的形态,大核 DNA 三维吸收图像和显微光度术定量分析数据表明,游仆虫大核 DNA 含量的变化仅发生在 S 期,S 期大核中 DNA 合成与大核改组带相联系。     

产酸克雷伯氏菌的吸附固定及其产氢研究

利用曲霉(Aspergillussp.XF101)所形成的菌丝球吸附产氢细菌产酸克雷伯氏菌(Klebsiella oxytocaHP1),当曲霉培养时间为50 h,菌丝球直径为1.3~1.8 mm,菌悬液pH值为5.0~6.0,吸附温度为30℃,吸附时间为1.5 h时,可获得最佳吸附效果,吸附率可达99%以上.利用菌丝球固定产氢菌可进行连续产氢,其最大产氢速率为18 mmol/L.h,平均产氢速率为1.7 mmol/L.h,持续产氢时间为15 d.     

海洋真菌杀虫活性的初步研究

对采集自浙江舟山海域底泥、福建省九龙江口红树林及福建省云霄县红树林共188株海洋真菌代谢产物的杀小杆线虫（Rhabditis sp．）和卤虫（brineshrimp）活性进行初步研究．筛选出#164菌株代谢产物对小杆线虫显示了较好的杀害活性，其LC90小于0．5mg／mL．#122菌株代谢产物对卤虫显示了较强的麻痹效应．#305菌株代谢产物对卤虫的LG。仅为75μg／mL．此外，对188株海洋真菌代谢产物的乙酰胆碱酯酶抑制活性进行研究．筛选出#229菌株代谢产物和#170菌株代谢产物具有较强的乙酰胆碱酯酶抑制活性,IC50分别为30／μg／mL和25／μg／mL．这些活性菌株具有产生杀线虫剂或乙酰胆碱酯酶抑制剂的特性．     

WP2深海细菌基因组文库的构建和克隆子测序比对分析

以pUC19质粒DNA作为载体,用BamH1酶切、碱性磷酸酶处理后,分别与Sau3AⅠ部分酶切的Shewanella sp.(WP2) 基因组DNA 2-6kb的DNA片段连接,电击转化大肠杆菌DH5 α感受态,在含有Amp的LB平板上筛选重组子,得到转化子约5～6×103;随机挑取100个克隆子,经DNA测序,通过在网络数据库中进行BLASTX分析,得到一系列相对保守蛋白的比对结果.这些结果为遗传背景不清楚的细菌的研究,提供了一条从分子水平上探讨的技术路线.     

Sodium Acetate Stimulates PHB Biosynthesis in Synechocystis sp. PCC 6803

IntroductionA large variety of bacteria are able to synthesizepolyhydroxyalkanoic acids (PHAs) and to depositlarge amounts of these polyesters as insolubleinclusions in cytoplasm[1 ] . PHAs have attractedthe interest of the chemical industry because oftheir biodegradable properties for applications invarious technical,medical,and pharmaceuticalapplications[2 ] .Poly-β-hydroxybutyrate(PHB) isatypical PHA that is produced by heterotrophicbacteria,such as Alcaligenes eutrophus andEscherichi…