醇水催化7-羟基喹啉质子迁移过程的反应机理研究

用量子化学B3LYP方法在6-311G*基组水平上研究了7-羟基喹啉二水和二甲醇复合物分子间的相互作用和水助及醇助催化质子迁移反应,优化得到了反应物、过渡态和生成物的几何结构,结果表明,在水助及醇助催化质子迁移过程中,3个氢原子都参与了迁移过程,醇助催化质子迁移反应途径在甲醇溶液中的活化能垒比水助催化质子迁移反应低,在甲醇溶液中的反应比在水溶液中的反应更容易.     

模拟酸雨对小黑杨幼苗生长和光合特性的影响

目的 研究小黑杨(Populus simonii × P. nigra)幼苗生长、生理特性和叶片光系统Ⅱ(PSⅡ)活性对酸雨胁迫的响应情况,为其在酸雨沉降日趋频发的北方地区栽植提供参考。方法 以小黑杨为研究材料,对其连续喷施不同酸度[pH为2.5、4.5和7.0(CK)]的模拟酸雨,待小黑杨叶片出现明显病症时,测定其生长、叶片超微结构、抗氧化酶和光系统Ⅱ活性指标。结果 与对照相比,pH 4.5的模拟酸雨处理下小黑杨株高、茎粗、叶片数和叶面积显著增加;叶片颜色变浅绿色,但叶绿体结构紧凑,类囊体排列规则,未见淀粉粒,嗜锇滴数量略增多。而pH 2.5模拟酸雨处理的小黑杨幼苗茎粗和叶面积显著降低;叶片颜色变黄、叶尖和叶脉出现明显斑点,且细胞膜局部破损,叶绿体体积增大,类囊体间隙增大,可见少量淀粉粒,嗜锇滴数量和体积明显增加。模拟酸雨处理的小黑杨叶片中超氧阴离子 {\mathrm{O}}_2^{\stackrel{-}{\underset{·}{\mathrm{}}}}产生速率、过氧化氢(H₂O₂)含量和过氧化氢酶活性较CK显著增加,且酸度越大,增幅越大;而过氧化物酶活性和超氧化物歧化酶活性随酸度的增大表现为先升后降。其中,pH 2.5模拟酸雨处理杨树叶片的可变荧光强度(V_L、V_K、V_J、V_I)和诱导曲线初始斜率(M_O)显著高于CK,但叶绿素荧光曲线面积(Fix Area)和质体醌库的大小(S_m)显著低于CK。pH 4.5模拟酸雨处理中,仅V_L和V_K显著高于CK,而其他荧光参数与CK差异不显著。结论 酸雨对小黑杨生长的影响主要取决于其pH,pH 2.5模拟酸雨处理抑制小黑杨生长,并且叶片出现坏死斑点症状时,叶绿体结构异常,类囊体排列不规整,光系统Ⅱ电子传递受到抑制;而pH 4.5模拟酸雨处理促进小黑杨生长、叶片超微结构表现正常,小黑杨幼苗对pH 4.5酸雨沉降具有一定抗性。     

快速诱导细胞凋亡方法探讨

[目的]利用流式细胞仪检测细胞凋亡在基础研究、疾病诊断及预后预测及评价中具有重要的应用价值.补偿调节所需的单阳染色管的制备,是流式细胞术检测凋亡过程的一个重要步骤.探讨了快速诱导不同细胞系和原代细胞凋亡的方法,优化用于检测细胞凋亡的流式单阳染色管快速制备.[方法](1)分别用100 μmol/L H2O2、体积分数4％...     

Colonial ascidians from the Foveaux Strait region of New Zealand

Colonial ascidians collected from wharf piles and natural substrata from Bluff Harbour and Stewart Island in the South Island of New Zealand are described in this paper. Two species, Lissoclinum violaceum sp. nov. and Didemnum marineae sp. nov. are new to science and described for the first time. The ascidian fauna in this region is a mixed assemblage of southern species, species with a New Zealand-wide distribution, and two species with trans-Tasman affinities.

www.zoobank.org/urn:lsid:zoobank.org:pub:37DC0D4B-8FB9-4F1D-A5A0-E9CAB3203447     

头孢美唑合成方法研究

以7-ACA(7-氨基头孢烷酸)、对甲苯磺酰氯为主要原料合成了头孢美唑,反应分4步进行,4步反应总收率约为57%,与传统合成方法相比,该方法具有反应步骤少,反应总产率高,中间体稳定,反应原料价格低廉等优点,具有广泛的应用前景,因此,该合成路线和工艺在工业生产上具有一定的实用价值。     

基于注意力机制的红外小目标检测方法

针对红外小目标占用像素较少、背景相似性强、网络容易受到背景杂波信息干扰的问题,提出了一种基于注意力机制的红外小目标检测方法。利用注意力机制模块抑制背景杂波,增强小目标特征,并使用红外小目标检测模块实现检测任务;为了增强网络鲁棒性,通过高斯噪声与原图通道堆叠输入的数据增强方式提升网络抗杂波干扰的能力。实验表明,提出的方法在MDvsFA数据集中的性能超过了目前最新的对比算法。     

Curcumin通过Wnt信号通路抑制乳腺癌细胞MCF-7增殖的研究

目的 观察姜黄素(Curcumin)对乳腺癌细胞MCF-7增殖的影响,以及对细胞内Wnt信号通路的影响,探索Curcumin可能存在的抑制乳腺癌细胞增殖的分子机制.方法 体外培养人乳腺癌细胞MCF-7,并用不同浓度的Curcumin作用不同的时间.用MTT检测Curcumin对MCF-7细胞生长情况的影响;流式细胞仪观察经Curcumin作用后细胞周期的改变;RT-PCR和Westernblot分别检测细胞内β -catenin和下游靶基因CyclinD1的mRNA和蛋白水平的表达.结果 MTT结果显示Curcumin可以抑制MCF-7的增殖,并具有剂量-时间依赖性.在浓度为20 μmol·L-1时,对细胞生长的抑制作用最为明显.流式细胞仪观察细胞周期的结果提示,Curcumin能够阻止MCF-7细胞由G1期进入S期,提高Go/G1期细胞的百分比.RT-PCR和Western blot结果显示,Curcumin显著降低了细胞内β-catenin和CyclinD1的mRNA和蛋白水平的表达,且呈剂量-时间依赖性.结论 Curcumin能够抑制MCF-7细胞胞浆内β -catenin蛋白进入胞核,阻断Wnt信号转导通路.进而抑制下游靶基因CyclinD1的表达,阻止MCF-7由G1期进入S期,有效抑制了MCF-7细胞的增殖.     

Notes on astogeny of some Petraliellidae (Bryozoa) from Australia

Members of the bryozoan family Petraliellidae share the capacity to develop basal rhizoids, which anchor the unilaminar, semi-repent parts of the colonies above the substratum, and enable them to overgrow other, competing sessile forms. Little is known of the larval behaviour and settlement, or the early astogeny of species. Ancestrulate colonies of the Australian Tertiary lunulitiform species Smittia biincisa are referred to the genus Riscodopa, and together with Riscodopa paucipora sp. nov. are described and compared with the Recent species R. cotyla and R. parva from New Zealand, and with R. hyalina sp. nov. from New South Wales, Australia. All the Recent species are known to develop basal rhizoids, and an early astogeny similar to that of many other small, rooted bryozoans, comprising the post-metamorphosis development of a binary complex, including rhizoid and feeding elements, is inferred for Riscodopa. Observations on living Hippopetraliella magna from Queensland suggest that both the ancestrular morphology and early astogeny show a capacity for semi-repent growth, even though they do not include rhizoid development. Larvae metamorphose without direct attachment, and the ancestrula develops elongated, partially calcified supporting processes, which raise the early stages of growth above the substratum. A similar kind of ancestrula has been found in preserved specimens of Mucropetraliella ellerii.     

Revision of the Neotropical species of the tribe Euderomphalini (Hymenoptera: Eulophidae)

The Neotropical species and genera of the tribe Euderomphalini (Eulophidae: Entedoninae) are revised. Five genera are described as new: Cabeza, including six species (baeostigma (§, ¦), canaliculata (§), laticeps (¦), petiolata (§), planiscapus (§), ugaldei (§)); Itahipeus, including two species (brasilicola (§, ¦), euryceps (¦)); Monterrondo, including one species (aphelosoma (§)); Sifraneurus, including one species (strigifer (§)); Xenopomphale, including one species (sulcata (§)); all above-mentioned species are described as new. Five additional genera are included: Aleuroctonus LaSalle and Schauff, with four species, one described previously: vittatus (Dozier) (§, ¦), and three described here: latiscapus (§), marki, (§, ¦) and metallicus (§); Entedononecremnus Girault, with 14 species, two described previously: krauteri Zolnerowich and Rose (§, ¦), unicus Girault (§, ¦), and 12 described here: bennetti (§, ¦), bimaculatus (§, ¦), convexus (§, ¦), crassicornis (§, ¦), depressus (§), fulgens (§), hansoni (§, ¦), imdasus (§, ¦), parfer (§, ¦), reticulatus (§), tripar (§) and unicarinatus (§); Euderomphale Girault, with two species, one described previously: flavimedia (Howard), and one described here: sulciscapus (§, ¦); Neopomphale LaSalle and Schauff, with 20 species, two described previously: aleurothrixi (Dozier) (§, ¦), quercicola (Dozier) (§, ¦), and 18 described here: azofeifai (¦), cerrobius (¦), depilis (§), dichrous (§, ¦), erecta (¦), graciliclava (§), longicornis (¦), longipilis (§, ¦), nonaequa (§, ¦), noyesi (§), pinguicornis (§, ¦), prymna (§), rubescens (§, ¦), rubii (§), silvestris (¦), transversa (§), umbonata (§, ¦), xenipennis (§); Dasyomphale LaSalle and Schauff, including one species (chilensis LaSalle and Schauff). The genera are placed in either one of three genus-groups, one of which is newly created. The species Euderomphale quercicola Dozier is newly combined to Neopomphale. Lectotypes are designated for Entedononecremnus unicus Girault, Euderomphale quercicola Dozier and Gyrolasia flavimedia Howard. Key to genera and species are included.     

Gastrointestinal helminths from fifteen species of Litoria and Nyctimystes (Anura: Hylidae) from Papua New Guinea

Three hundred and ninety‐nine individuals representing 10 species of Litoria and five species of Nyctimystes (Hylidae), L. arfakiana, L. bibonius, L. eucnemis, L. genimaculata, L. impura, L. infrafrenata, L. modica, L. nasuta, L. thesaurensis, L. wollastoni, N. gularis, N. kubori, N. papua, N. pulcher and N. semipalmatus collected in Papua New Guinea were examined for helminths. Gravid individuals representing one species of Monogenea (Parapolystoma bulliense), one species of Digenea (Mesocoelium monas), 18 species of Nematoda (Aplectana krausi, Aplectana macintoshi, Aplectana zweifeli, Cosmocerca novaeguineae, Falcaustra papuensis, Icosiella papuensis, Maxvachonia adamsoni, Maxvachonia ewersi, Meteterakis crombiei, Moaciria moraveci, Ochoterenella papuensis, Oswaldocruzia bakeri, Parapharyngdon maplestoni, Parathelandros allisoni, Parathelandros andersoni, Physalopteroides milnensis, Rhabdias australiensis, Seuratascaris numidica) and one species of Acanthocephala (Acanthocephalus bufonis) were found. Also included were immature forms representing one species of Cestoda (as a metacestode), three species of Nematoda (Abbreviata sp., Rictulariidae gen. sp., Ascarididae gen. sp. in cysts), one species of Acanthocephala (unidentified cystacanth), and one species of Pentastomida [Raillietiella sp. (nymph)]. The mean helminth species richness for infected hosts was 1.3±0.6 SD (range one to three species). Sixty‐seven new host records and two new locality records are reported.