新疆生态用水量的初步估算

以新疆为例 ,在干旱区生态用水的概念与分类基础上 ,依据部分试验资料及理论公式推导结果 ,确定了各类生态用水的用水定额 ,并以林业、草场资源等统计数据为依据 ,对新疆 1 995年的生态用水进行了初步估算。结果表明 ,全疆生态用水总量达 2 3 7.9× 1 0 8m3。其地区分布情况是北疆占 1 7.8%,东疆占 5.4 %,南疆占 76.8%。就其类型而言 ,天然植被生态用水量最大 ,其中又以低地草甸为最大     

Phytotoxic substances with allelopathic activity may be central to the strong invasive potential of Brachiaria brizantha

The grass Brachiaria brizantha, native to eastern Africa, becomes naturalized and dominant quickly in the non-native areas. It was hypothesized that phytotoxic chemical interaction between this plant and native plants may play an important role in the invasion of B. brizantha. However, no potent phytotoxic substance has been reported in this species. Therefore, we investigated possible allelopathic activity and searched for phytotoxic substances with allelopathic activity in B. brizantha. An aqueous methanol extract of B. brizantha inhibited the growth of roots and shoots of garden cress (Lepidium sativum), lettuce (Lactuca sativa), timothy (Phleum pratense) and ryegrass (Lolium multiflorum) seedlings. The extract was purified by several chromatographic runs and three allelopathically active substances were isolated and identified by spectral analysis as (6R,9R)-3-oxo-α-ionol, (6R,9S)-3-oxo-α-ionol and 4-ketopinoresinol. (6R,9R)-3-Oxo-α-ionol and (6R,9S)-3-oxo-α-ionol inhibited root and shoot growth of garden cress at concentrations greater than 30 and 10 μM, respectively. The activity of (6R,9S)-3-oxo-α-ionol was 5.3- to 6.2-fold that of (6R,9R)-3-oxo-α-ionol. The stereochemistry of the hydroxyl group at position C-9 may be important for the inhibitory activities of those compounds. 4-Ketopinoresinol inhibited root and shoot growth of garden cress at concentrations greater than 30 μM. The growth inhibitory activity of (6R,9S)-3-oxo-α-ionol was the greatest and followed by 4-ketopinoresinol and (6R,9R)-3-oxo-α-ionol. These results suggest that those phytotoxic substances may contribute to the allelopathic effect caused by B. brizantha and may be involved in the invasion of B. brizantha.     

毛乌素沙地景观格局变化研究

通过对毛乌素沙地不同时期的景观分类和制图以及景观格局计算,分析了50年代到90年代毛乌素沙地景观动态与景观格局变化的特征和模式。研究表明,50年代以来,毛乌索沙地景观发生了巨大变化,流动沙地、半固定沙地面积大幅度增加,固定沙地面积迅速减少,农田面积明显增加,草原、柳湾和盐湿低地等面积显著减少。50年代时,整个景观以流动沙地和固定沙地占优势,而90年代,则以流动沙地占绝对优势。伴随着荒漠化的发展,各种景观要素类型之间相互转化,景观格局发生显著变化。固定沙地面积减少伴随着斑块的破碎化,大型斑块数量减少,小型斑块数量增加;流动沙地面积增加的同时,一方面,较小的斑块不断联合形成更多的大型斑块,另一方面,流动沙地不断向固定、半固定沙地内部渗透,形成更多的小型斑块,使整个景观更加破碎。不合理的人类活动是荒漠化扩展及景观格局发生显著变化的主要驱动因素。     

Enhancement of specific growth rate of iron-oxidizing bacteria by glucose

Summary Thiobacillus ferrooxidans, isolated from mine water, utilized not only ferrous iron but also glucose to grow. By using ferrous-iron medium containing glucose, a 7-fold population increase was obtained after 96 h of incubation. The ability to oxidize ferrous iron was maintained during cultivation on the iron-glucose medium.     

Distribution and species composition of juvenile and adult scombropids (Teleostei,Scombropidae) in Japanese coastal waters

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (<200 mm standard body length, S_L) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (>400 mm S_L) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.     

Syntheses and characterization of Co(III) binuclear complexes with bis(catecholate) ligands containing an acetylene linker

Three binuclear Co(III) complexes with 5,5′-(buta-1,3-diyne-1,4-diyl)bis(3-tert-butylcatechol) (L1), 5,5′-(2,5-dimethoxy-1,4-phenylene)bis(ethyne-2,1-diyl)bis(3-tert-butyl-catechol) (L2) and 5,5′-(4,4′-(buta-1,3-diyne-1,4-diyl)bis(2,5-dimethoxy-4,1-phenylene))bis(ethyne-2,1-diyl)bis(3-tert-butyl-catechol) (L3) have been prepared. The triple bond-containing L1, L2 and L3 ligands were synthesized by a cross-coupling reaction. These complexes were characterized by elemental analyses, electrochemical measurements, ¹H NMR and UV-Vis spectra. In [Co₂(bpy)₄(L1)]²⁺, electrochemical oxidation of the complexes occurs at the bridges as two closely spaced one-electron couples. UV-Vis spectra reveal that chemical oxidation of [Co₂(bpy)₄(L1)]²⁺ using Ag⁺ occurs as a two-electron process forming [Co₂(bpy)₄(L1^Cat,SQ)]³⁺ or [Co₂(bpy)₄(L1^SQ,SQ)]⁴⁺. On the other hand, [Co₂(bpy)₄(L2)]²⁺ and [Co₂(bpy)₄(L3)]²⁺ exhibit different oxidation behavior under the same experimental conditions. In this report we discuss the role of the distance between the two metal atoms on the oxidative behavior of binuclear Co(III) complexes.     

编码锌指蛋白的人类新基因TFL76的电子克隆

目的：根据基因同源同功原理电子克隆人类新基因。方法：利用基于基因识别软件Genescan和EST拼接的同源基因克隆法得到人类新基因序列TFL76,再利用生物信息学数据库和软件对其进行功能的预测和分析。结果：TFL76的cDNA序列长2268bp,开放阅读框编码677个氨基酸残基,含12个连续的C2H2型锌指基序,其分子量为76kDa。编码区序列被4个内含子分割。染色体定位于19q13．4。此位点存在很多与胃癌、膀胱癌、乳腺癌等癌症相关的基因。TFL76的N末端含有多种蛋白激酶的磷酸化位点和核定位信号。结论：TFL76可能是一个和癌症相关的核转录因子。     

亚热带森林乔木树种DNA条形码研究——以哀牢山自然保护区为例

作为新一代植物志iFlora的重要组成部分,DNA条形码已经成为物种鉴定中重要且有效的方法。本研究以亚热带森林的乔木树种为研究对象,开展了DNA条形码的尝试性工作。为评估DNA条形码对鉴定亚热带森林树种的有效性,收集并研究了来自哀牢山自然保护区内5l科111属中204个树种的525个乔木个体。结果显示,所选4个DNA片段（rbcL,matK,trnH-psbA和ITS）的PCR扩增成功率都超过90％;测序成功率rbcL和matK最高,分别为90．7％和90．5％,trnH-psbA次之（83．6％）,ITS最低（73．5％）,表明4个片段在亚热带森林乔木中都具有较好的通用性。应用BLAST与NJ Tree两种方法,对物种和属水平的鉴别成功率进行统计,发现单片段中ITS最高,分别为68．4％-81．3％和99．0％～100％,核心条码rkL和matK组合的成功率是52．8％～60．2％和86．7％～90．5％,再与补充条码trnH-psbA和ITS联合,可以成功鉴别74．7％～79．6％哀牢山自然保护区亚热带森林中的乔木物种。由于ITS片段在亚热带森林部分重要树种类群（樟科和壳斗科等）中的测序成功率较差,所以对这些植物类群采用trnH-psbA作为DNA条形码是一个更好的选择。     

Prognostic Value of FDG PET Imaging in Patients with Laryngeal Cancer

Background and Purpose

To investigate the prognostic value of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with laryngeal cancer.

Materials and Methods

The study included 51 patients of whom 30 underwent definitive radiotherapy with or without chemotherapy and 21 underwent radical surgery with or without adjuvant chemoradiation therapy. FDG uptake by both the primary lesion and the neck node was measured using the maximum standardized uptake value (SUVmax). The effects of clinicopathological factors including primary tumor SUVmax and nodal SUVmax on progression-free survival, local control, nodal progression-free survival, and distant metastasis-free survival were evaluated using the log-rank test and Cox method.

Results

The median duration of follow-up was 48.6 months (range 8 to 82.1 months). Univariate analysis showed that nodal SUVmax, N status, and tumor TNM stage were significantly associated with recurrence, whereas primary tumor SUVmax, age, treatment strategy and T status were not. Multivariate analysis demonstrated that only the nodal SUVmax was a significantly unfavorable factor for progression-free survival (p = 0.029, hazard ratio 0.54, 95% CI 0.38-0.87) and nodal progression-free survival (p = 0.023, hazard ratio 0.51, 95% CI 0.34-0.81). ROC curve analysis and log-rank test showed that patients with a high nodal SUVmax (≧4) had a significantly lower progression-free survival rate than those with a low SUVmax (<4; p<0.0001).

Conclusions

The pretreatment SUVmax of nodal disease in patients with laryngeal cancer is prognostic for recurrence.