中国生态地理区城市水资源利用效率时空分异特征

我国水资源面临的形势十分严峻,水资源短缺、水污染严重、水生态环境恶化等问题突出,已成为制约社会经济可持续发展的主要瓶颈。基于分类数据包络分析（Categorical DEA）对2007-2016年中国生态地理区城市水资源利用效率进行测算,对其时间变化、空间分布以及空间收敛性进行分析。结果表明：1）2007-2016年期间全国城市水资源利用效率总体处于低效率状态,随时间高低交错波动式发展,整体呈先降后升势态;2）生态地理区城市水资源利用综合效率由高到低依次为温带干旱区、温带半干旱区、温带半湿润区、温带湿润区、亚热带湿润区,呈西北向东南逐渐递减的空间分布格局,生态地理区纯技术效率区间差异较大,但空间分布规律不显著,区域规模效率间差距小,且无明显空间分布规律;3）纯技术效率低效是制约全国水资源利用综合效率提升的主要因素,生态地理区间纯技术效率巨大差距导致全国纯技术效率整体低效,也是全国水资源利用综合效率低效的根本原因;4）生态地理区水资源利用综合效率区域差距逐渐缩小,主要是因为高效率区域效率值向低效率区域靠拢,区域间低效向高效的"追赶效应"不明显。     

Functional analysis of microtubule-binding domain of bovine MAP4

Bovine microtubule-associated protein 4 (MAP4) consists of an amino-terminal projection domain and a carboxyl-terminal microtubule-binding domain. The carboxyl-terminal domain of MAP4 is further divided into three subdomains: a region rich in proline and basic residues (Pro-rich region), a region containing four repeats of an assembly-promoting (AP) sequence, which consists of 22 amino acid residues (AP sequence region), and a hydrophobic tail region (Tail region). The subdomain structure of MAP4 microtubule binding domain is similar to those of other MAPs (MAP2 and tau). In order to study the function of each subdomain per se of bovine MAP4 microtubule-binding domain, we purified a series of truncated fragments of MAP4, expressed in Escherichia coil. Binding affinity of the PA4T fragment (containing the Pro-rich region, the AP sequence region and the Tail region) is only four times higher than that of the A4T fragment (containing the AP sequence region and the Tail region), while the microtubule nucleating activity of the PA4T fragment is far greater. We propose that the Pro-rich region promotes the nucleation of microtubule assembly. The A4 fragment (corresponding to the AP sequence region) stimulated the assembly of tubulin into coldstable amorphous aggregates. The AP sequence region of MAP4 failed to promote microtubule assembly. On the other hand, the fragment has an activity to stimulate microtubule elongation. The function of the MAP4 Tail region is not clear at present. The A4T fragment (containing the AP sequence region and the Tail region) promote both microtubule nucleation and elongation step, but the A4 fragment only promotes microtubule elongation, suggesting that the Tail region is indispensable for the nucleation step. However, the fragment containing only the Tail region could not bind to microtubule. Although MAP4 was considered to be long, thin and flexible molecule, never the Tail region may contribute to be the proper folding of MAP4, and/or may interact with other molecules. We concluded that both the Pro-rich region and the AP sequence region take part in the promotion of tubulin polymerization, and that the former is important for the lateral protofilament-protofilament interaction, and the latter is important for the longitudinal affinity between each tubulin dimer in a protofilament.     

A bovine papillomavirus E1-related protein binds specifically to bovine papillomavirus DNA.

The E1 open reading frame of bovine papillomavirus (BPV) was expressed as a RecA-E1 fusion protein in Escherichia coli. The bacterially expressed RecA-E1 protein exhibited sequence-specific DNA binding activity; strong binding to the region from nucleotides 7819 to 93 on the BPV genome (designated region A) and weak binding to the adjacent region from nucleotides 7457 to 7818 (region B) were observed. The interaction between the BPV-derived RecA-E1 protein and region A appeared to be highly specific for BPV DNA, as no comparable binding was detected with heterologous papillomavirus DNAs. Binding to region A was eliminated by digestion of region A at the unique HpaI site, which suggests that the RecA-E1 binding site(s) was at or near the HpaI recognition sequence. Binding to region B but not region A was observed when nuclear extracts from ID13 cells were used as a source of E1 proteins. The absence of region A binding by ID13 extracts may reflect a negative regulation of E1 DNA binding activity.     

Sequencing of selected regions of the human immunoglobulin heavy-chain gene locus that completes the sequence from JH through the delta constant region.

Much of the nucleotide sequence between the start of the joining region and the end of the immunoglobulin heavy chain delta gene has already been determined. However, two gaps existed in potentially functionally important regions in this sequence: the region between the 3' end of the joining region and the heavy chain enhancer region and that between the enhancer and the mu constant region. We have determined the nucleotide sequences of these regions. The 734 bp between the joining and enhancer regions contained no additional joining regions. The 4525 bp region between the heavy chain enhancer and the mu constant region contains the mu switch region, which consists of pentameric repeats. Approximately 60% of these repeats are GGGCT and GAGCT. With the determination of these sequences, the entire region of the heavy chain locus starting upstream of the joining region to downstream of the last exon of the delta constant region (a total of more than 29 kb) has now been sequenced.     

香蕉果实特异性ACC合酶基因启动子区的克隆及其功能初探

根据本实验室所获得的香蕉果实特异性ACC合酶cDNA序列,以改进的接头连接PCR方法通过两次步行从香蕉基因组中分别扩增并克隆了其基因5′旁侧区近端1.2kb和远端1.6kb的片段。通过拼接,构建出含有2505bp启动子区和转录起始位点下游86bp的共2591bp的基因5′旁侧区片段;其启发性动子区中34至28为推测的TATA盒序列,158至146为推测的CCAAT盒,与其它植物基因启动子结构相类似。将2.5kb启动子片段与β-葡糖苷酸酶(GUS)基因编码序列融合,用基因枪法将构建的嵌合基因转入香蕉叶、根和果实的细胞后,只在果实细胞中观察到报告基因的瞬时表达,从功能上证明了此25kb的启动子片段具有指导报告基因在香蕉果实中特异性表达的作用。同时构建5个含不同5′端缺失启动子与GUS融合基因的表达载体。瞬时表达结果表明可能负责果实特异性表达的调控区存在于转录起始位点至-1111的启动子区中,而在-1111至-608区间可能存在一个正控制区。     

PCR-SSCP技术在假丝酵母属菌种鉴别中的应用

选取中国工业微生物菌种保藏管理中心(CICC)保藏的假丝酵母属的7个种30株菌, 对其rDNA的ITS1区及ITS2区进行了PCR-SSCP指纹图谱分析, 结果表明在假丝酵母属种水平的区分鉴定中, ITS1区与ITS2区的PCR-SSCP图谱均能对本研究所选7个种的菌株进行显著区分, 比较两个区段的PCR-SSCP图谱及鉴别效果, 发现ITS2区的应用效果要优于ITS1区。     

Nucleotide sequence of the promoter region of the melibiose operon of Escherichia coli

The nucleotide sequence of the promoter region of the melibiose operon of E. coli was determined. Consensus sequences for the -35 region, the Pribnow box and the binding site for cyclic AMP receptor protein were found in this region. The possible secondary structure of this DNA region was very similar to that of the promoter region of the lactose operon. A possible initiation ATG preceded by a Shine-Dalgarno sequence with proper spacing was present just downstream of the promoter region. The possible sequence of 52 amino acid residues in the NH2 terminus of the alpha-galactosidase were determined.     

The postnatal histology of the epididymis in buffalo (Bubalus bubalis).

The epididymis of buffalo is differentiated into 6 regions. The head represents the first 3 regions, the body the 4th region and the tail the 5th and 6th region. At 3-30 weeks, the epithelium is simple high columnar with few basal cells in region I, simple low columnar with few basal cells in region II, pseudostratified low columnar in regions III, IV, V, and pseudostratified low columar in region VI. As age advances, the epithelium increases in height and shows a tendency toward advanced pseudostratification. The basal cells are greater in number in regions III, IV and V than in the other regions of the epididymis. The epithelial cells contain stereocilia in region I at 3 weeks and regions III, IV and V at 30 weeks, whereas they are absent in regions II and VI. The tubules in region I are the smallest in diameter while the tubules in region VI have the largest diameter.     

干旱沙区不同种源的绵毛优若藜表现性比较

在民勤沙生植物园．通过室内和田间试验,对引自美国西部沙漠区和草原区的绵毛优若藜的物候期、种子发芽温度、植物的生长和地上部分营养成分进行了观测与测定。在昼夜变温条件下,草原区种子对温度的反应较迟钝．适宜的发芽温度应为5～25C;沙漠区种子发芽适宜的温度为lO～30C。两个种源的绵毛优若藜均在6～7月间生长量最大。草原区种源的植株月平均生长量大于沙漠区种源的生长量。不同种源植物的物候期相差较小,除开花期外,沙漠区植物的展叶、孕蕾、结果和叶变色均早于草原区。在民勤沙区,绵毛优若藜表现为准常绿性。沙漠区植株的营养成分含量略低于草原区植株。     

川西三大干流水电开发影响区种子植物区系研究

在对川西雅砻江、大渡河和岷江三大干流水电开发影响区种子植物进行调查的基础上,对其区系特征进行了统计分析和比较研究,结果表明:(1)岷江和大渡河影响区裸子植物科、属、种数量多于雅砻江,被子植物属、种数量远少于雅砻江.(2)在科水平上均具有明显热带区系性质;在属水平上显示出热带和暖温带性质,雅砻江影响区热带属的比例高于温带属,岷江和大渡河则相反.(3)中国种子植物属15大分布区类型在岷江影响区均有分布,在雅砻江、大渡河各有1项没有出现.(4)大渡河和岷江影响区优势科属较雅砻江明显.(5)大渡河影响区属的系数"相对最低,区系丰富度较大.(6)岷江影响区特有属最多,雅砻江最少.(7)雅砻江和岷江影响区珍稀濒危及保护物种较大渡河多.     

Identification of mouse adenovirus type 1 early region 1: DNA sequence and a conserved transactivating function.

The left end of the genome of mouse adenovirus type 1 (also known as strain FL) was characterized by determination of the DNA sequence, amino acid similarities with early region proteins of primate adenoviruses, and a functional assay. Several specific DNA sequence features were similar to those found in human adenoviruses, and open reading frames from this region could encode proteins similar to human adenovirus early region 1A and early region 1B proteins. DNAs from this region were tested in transient-expression assays in human and mouse cells were found to transactivate the human adenovirus type 5 early region 3 promoter fused to the chloramphenicol acetyltransferase gene. The data indicate structural and functional homologies between mouse adenovirus type 1 early region 1 and early region 1 of primate adenoviruses.     

Identification of the region in Cdc42 that confers the binding specificity to activated Cdc42-associated kinase

The Rho family small G-protein Cdc42 has been implicated in a diversity of biological functions. Multiple downstream effectors have been identified. How Cdc42 discriminates the interaction with its multiple downstream effectors is not known. Activated Cdc42-associated tyrosine kinase (ACK) is a very specific effector of Cdc42. To delineate the Cdc42 signaling pathway mediated by ACK, we set about to identify the specific ACK-binding region in Cdc42. We utilized TC10, another member of the Rho family of G-proteins that is 66.7% identical to Cdc42, to construct TC10/Cdc42 chimeras for screening the specific ACK-binding region in Cdc42. A region between switch I and switch II has been identified as the specific ACK-binding (AB) region. The replacement of the AB region with the corresponding region in TC10 resulted in the complete loss of ACK-binding ability but did not affect the binding to WASP, suggesting that the AB region confers the binding specificity to ACK. On the other hand, replacement of the corresponding region of TC10 with the AB region enabled TC10 to acquire ACK-binding ability. Eight residues are different between the AB region and the corresponding region of TC10. The mutational analysis indicated that all eight residues contribute to the binding to ACK2. The assays for the Cdc42-mediated activation of ACK2 indicated that the AB region is essential for Cdc42 to activate ACK2 in cells. Thus, our studies have defined a specific ACK-binding region in Cdc42 and have provided a molecular basis for generating ACK binding-defective mutants of Cdc42 to delineate ACK-mediated signaling pathway.     

Dynamic analysis of a genomic island in Magnetospirillum sp. strain AMB-1 reveals how magnetosome synthesis developed

The entire structure of a 98 kb genomic region that abounds in genes related to magnetosome synthesis was first described in the Magnetospirillum sp. strain AMB-1. The deletion of this 98 kb genomic region and the circular form after excision from the chromosome was detected by PCR amplification. This strongly suggests that the region has undergone a lateral gene transfer. The region has the characteristics of a genomic island: low GC content, location between two repetitive sequences, and the presence of an integrase in the flanking region of the first repetitive sequence. This 98 kb genomic region has the potential for transfer by the integrase activity. Comparative genome analysis revealed other regions with a high concentration of orthologs in magnetic bacteria besides the 98 kb region, and magnetosome synthesis seemed to need not only the exogenous 98 kb region, but also other orthologs and individually originating genes.     

小麦根尖细胞分化过程中DNA,RNA和蛋白质含量变化的研究

小麦(Triticum aestivum L.)种子在25℃条件下萌发3d,根生长至1～2cm长时,于双筒解剖镜下严格切取根分生区、伸长区和成熟区。用专一性荧光染料Hochest33258、Pyronin G和FITC分别染细胞核DNA、RNA和蛋白质,并用自动图像分析技术和细胞荧光测定术分别测定三个区中各125个细胞核DNA的相对含量和各100个细胞中RNA和蛋白质的相对含量。核DNA相对含量随着根尖细胞分化的进程,DNA含量递增,成熟区细胞中含量最高。RNA的相对含量则与之相反,在分生区细胞中含量最高,成熟区细胞中含量最低。蛋白质的相对含量则在伸长区细胞中最高,分生区细胞中最低。讨论了根尖细胞分化过程中DNA、RNA和蛋白质三者之间变化的一些内在联系。     

北方山溪鲵精巢显微结构的年周期变化

2001、2003年1～12月自秦岭北坡的溪流中,共采集北方山溪鲵(Batrachuperus tibetanus)38尾(体重27～38g)做精巢切片,在光镜下观察精巢显微结构的年周期变化。结果表明：北方山溪鲵为非连续型精子发生,精原细胞增生有两个高峰期,分别在9～11月和翌年的3～5月,初级精母细胞的成熟分裂期在6月末至7月,精子形成期在7月末至8月。每个精巢小叶可明显地分为深层的非成熟区和浅层的成熟区。非成熟区为精原细胞的贮存区,可增殖并延伸为增殖区。增殖区再发育为成熟区,为精子形成和存储的区域。在精子排出后,成熟区转变为排空区,后者被新的增殖区更替。北方山溪鲵精巢所有小叶同步发育,无精子成熟波。     

Insertional mutagenesis of the cauliflower mosaic virus genome

A series of small insertions has been introduced into the various translational reading frames of the DNA of a "severe" strain of cauliflower mosaic virus (CaMV). A selectable gene (the kanamycin phosphotransferase gene of Tn903), flanked by a series of symmetrically arranged cloning sites taken from M13mp7, was used to prepare the site-specific mutants. In-phase insertions of 12 or 30 bp, which introduced unique SalI sites into reading regions I, III, IV, V and into the amino-proximal portion of region VI, destroyed infectivity. Insertions in the amino-distal portion of region VI, in the large intergenic region, and in region II retained infectivity. The amino-distal insertions in region VI reduced the severity of symptoms in plants. The insertion in region II destroyed aphid transmissibility. Longer DNA segments when inserted into region II or into the amino-distal portion of region VI destroyed infectivity, but similar insertions in the intergenic region were without effect on virus infection or development.     

The replication origin of pSC101: the nucleotide sequence and replication functions of the ori region

The nucleotide sequence of a 770-bp ori region of plasmid pSC101 is presented. The sequence shows homologies to some parts of Escherichia coli oriC and phage G4 ori. Several other features are an 80-bp A + T-rich region overlapping a part of the region homologous to oriC, three direct repeats of an 18-bp sequence adjacent to the A + T-rich region, a typical promoter sequence just upstream of the longest open reading frame (ORF) and a long inverted repeat sequence overlapping the putative promoter region. Analysis of successive deletions by BAL31 exonuclease demonstrated that one of the regions homologous to oriC along with the A + T-rich region are essential for autonomous replication of the plasmid. The three 18-bp repeats are responsible for incompatibility phenotype. The region containing the promoter-like sequence is required for expression of a trans-acting function.     

Changes in the DNA,RNA and Protein Contents During the Root-Tip Cell Differentiation of Triticum aestivum

One to two cm long root tips of Triticum aestivum L., after three days' germination at 25 ℃, each were cut into three regions--the meristem region, elongation region and mature region. The cells in different regions were stained with Hochest 33258, Pymnin G and FITC respectively. Nuclear DNA was measured by micmfluorometry with VIDAS digital image analysis system. The relative contents of RNA and protein in the cells were measured with a MPV-Ⅲ microspectrofluorometer. It was shown that the nuclear DNA content increased during root tip cell differentiation, being maximum in the mature region. The relative content of RNA was maximum in the meristem region, but decreased continuously during the growth of tissue. The relative content of protein was maximum in the elongation region, but minimum in the meristem region. The relationships among DNA, RNA, protein and cell differentiation were discussed.     

Shufflon: multi-inversion of four contiguous DNA segments of plasmid R64 creates seven different open reading frames.

The IncI alpha plasmid R64 was found to bear a highly mobile DNA segment which was designated as a clustered inversion region (J. Bacteriol. 165, 94-100, 1986). The clustered inversion region consists of four DNA segments designated respectively as A, B, C and D which differ in molecular size and restriction sites. The four DNA segments invert independently or in groups resulting in a complex DNA rearrangement. We now show the nucleotide sequence of the clustered inversion region of R64. The present results suggest that the clustered inversion region is a biological switch to select one of seven open reading frames whose primary structures at the region proximal to N-termini are constant while those at the C-terminal region are variable. A name, "Shufflon" was proposed to call this kind of the clustered inversion region.