A NEW SPECIES OF GENUS HABROPHLEBIODES ULMER (EPHEMEROPTERA: LEPTOPHLEBIIDAE)

Abstract  The present paper deals with a new species Habrophlebiodes zijinensis sp. nov. collected in Nanjing, Jiangsu Povince, China.     

Promoters from kin1 and cor6.6, two Arabidopsis thaliana low-temperature-and ABA-inducible genes,direct strong β-glucuronidase expression in guard cells,pollen and young developing seeds

The ability of most higher plants to withstand freezing can be enhanced by cold acclimation, although the freezing tolerance of plant tissues is also affected by their developmental stage. In addition, low temperature has pleiotropic effects on many plant developmental processes such as vernalization. The interaction between plant development and low temperature implies that some genes are regulated by both environmental factors and developmental cues. Although a number of cold-inducible genes from plants have been identified, information concerning their regulation during plant development is limited. In order to understand their developmental regulation and obtain possible clues as to function, the promoters of kin1 and cor6.6, two cold- and abscisic acid (ABA)-regulated genes from Arabidopsis thaliana, were fused to the -glucuronidase (GUS)-coding sequence and the resulting constructs were used to transform tobacco and A. thaliana. Transgenic plants with either the kin1 or cor6.6 promoter showed strong GUS expression in pollen, developing seeds, trichomes and, most interestingly, in guard cells. During pollen development, maximum GUS activity was found in mature pollen. In contrast, the maximum GUS activity during seed development was during early embryogenesis. These patterns of expression distinguish kin1 and cor6.6 from related lea genes which are strongly expressed during late embryogenesis. There was no major qualitative difference in patterns of GUS expression between kin1 and cor6.6 promoters and the results were similar for transgenic tobacco and Arabidopsis. Considering the results described, as well as those in an accompanying paper Wang et al., 1995, Plant Mol Biol 28: 605–617 (this issue), we suggest that osmotic potential might be a major factor in regulating the expression of kin1 and cor6.6 during several developmental processes. The implication of the results for possible function of the gene products is discussed.     

A nuclear genetic lesion affecting Saccharomyces cerevisiae mitochondrial translation is complemented by a homologous Bacillus gene.

A novel Bacillus gene was isolated and characterized. It encodes a homolog of Saccharomyces cerevisiae Pet112p, a protein that has no characterized relative and is dispensable for cell viability but required for mitochondrial translation. Expression of the Bacillus protein in yeast, modified to ensure mitochondrial targeting, partially complemented the phenotype of the pet112-1 mutation, demonstrating a high degree of evolutionary conservation for this as yet unidentified component of translation.     

Adeno-associated virus type 2-mediated transfer of ecotropic retrovirus receptor cDNA allows ecotropic retroviral transduction of established and primary human cells.

The cellular receptors that mediate binding and internalization of retroviruses have recently been identified. The concentration and accessibility of these receptors are critical determinants in accomplishing successful gene transfer with retrovirus-based vectors. Murine retroviruses containing ecotropic glycoproteins do not infect human cells since human cells do not express the receptor that binds the ecotropic glycoproteins. To enable human cells to become permissive for ecotropic retrovirus-mediated gene transfer, we have developed a recombinant adeno-associated virus type 2 (AAV) vector containing ecotropic retroviral receptor (ecoR) cDNA under the control of the Rous sarcoma virus (RSV) long terminal repeat (LTR) promoter (vRSVp-ecoR). Established human cell lines, such as HeLa and KB, known to be nonpermissive for murine ecotropic retroviruses, became permissive for infection by a retroviral vector containing a bacterial gene for resistance to neomycin (RV-Neo(r)), with a transduction efficiency of up to 47%, following transduction with vRSVp-ecoR, as determined by the development of colonies that were resistant to the drug G418, a neomycin analog. No G418-resistant colonies were present in cultures infected with either vRSVp-ecoR or RV-Neo(r) alone. Southern and Northern blot analyses revealed stable integration and long-term expression, respectively, of the transduced murine ecoR gene in clonal isolates of HeLa and KB cells. Similarly, ecotropic retrovirus-mediated Neo(r) transduction of primary human CD34+ hematopoietic progenitor cells from normal bone marrow was also documented, but only following infection with vRSVp-ecoR. The retroviral transduction efficiency was approximately 7% without prestimulation and approximately 14% with prestimulation of CD34+ cells with cytokines, as determined by hematopoietic clonogenic assays. No G418-resistant progenitor cell colonies were present in cultures infected with either vRSVp-ecoR or RV-Neo(r) alone. These results suggest that sequential transduction of primary human cells with two different viral vectors may overcome limitations encountered with a single vector. Thus, the combined use of AAV- and retrovirus-based vectors may have important clinical implications for ex vivo and in vivo human gene therapy.     

异源八倍体小冰麦体细胞无性系的建立及其染色体变异

从５个异源八倍体小冰麦（Ｔｒｉｔｉｃｕｍ －Ａｇｒｏｐｙｒｏｎ）的叶片、幼穗及成熟胚诱导愈伤组织,建立体细胞无性系,获得大量再生植株。附加一个冰草染色体组的异源八倍体小冰麦杂种无性系中３７．５％ 表现变异,其中非整倍体植株变异较多,很多变异的再生植株形态与小麦近似,同时出现一定数量染色体重排、交换、易位、断裂、融合等变异。结果表明,通过杂种无性系变异进行染色体基因转化及遗传修饰是一条可行的途径。实验还观察了小冰麦愈伤组织分化过程中绿点的形成过程,首次提出两种类型绿点,即芽绿点和根绿点,并描述了两者的差异     

Purification and characterization of M3 protein expressed on the surface of group A streptococcal type 3 strain C203

Abstract Monoclonal antibodies (mAbs) have been produced by immunizing BALB/C mice with whole M⁺ bacteria in incomplete Freund adjuvant and the resulting mAbs for M3 protein have been selected by an indirect immuno-fluorescent technique using formaldehyde-fixed M⁺ and M⁻ bacteria. Four mAbs reacted with a 65 kDa protein in an extract obtained from the cell wall of M⁺ bacteria after treatment with N -acetyl muramidase and lysozyme. The purified 65 kDa protein neutralized the phagocytic activity of rabbit anti-M3 antibody. The N-terminal amino acid sequence of the 65 kDa protein was identical with that of protein generated by the M3 gene which has been previously cloned and sequenced. The evidence indicates that the 65 kDa protein is M3 protein. The M3 protein bound not only human fibrinogen but also human serum albumin (HSA). When the M3 protein was purified by gel-filtration and ion-exchange chromatography in the absence of phenylmethyl sulfonyl fluoride (PMSF), four fragments (35 kDa, 32 kDa, 30 kDa, and 25 kDa) in addition to the intact molecule appeared. N-terminal amino acid sequence analysis showed that 35 kDa and 25 kDa fragments were ANAAD and DARSV, respectively, being identical at positions 1–5 and 198–202 to the M3 gene derived protein. Therefore, the 35 kDa and 25 kDa fragments, which were presumed to be cleavage products, may be derived from the C-terminal part and N-terminal part of the intact molecule, respectively. When the effect of purified M3 protein in the bactericidal activity of normal human blood in the presence of M⁻ bacteria was investigated, the M3 protein was responsible for the organism's resistance to attack by phagocytic cells.     

Argyrophilic nucleolar organizer regions

Silver staining techniques developed to demonstrate argyrophilic nucleolar organizer regions (Ag-NORs) have been widely applied in a variety of cell kinetic studies, using the mean number of AgNORs in tumour cells as a marker for malignancy of certain types of neoplasms. However, the AgNOR techniques currently available are not entirely satisfactory, as unspecific silver precipitates readily form in the sections. On the other hand, the contrast staining, may be so weak as to render identification of the AgNORs difficult. In the present study, some of the key factors influencing the outcome of AgNOR staining were evaluated in a more systematic way. A modified AgNOR staining procedure is now proposed, giving highly contrasting AgNORs with minimal unspecific silver precipitation, thus facilitating both manual and computerized counting. The new technique involves the use of microwave irradiation in order to shorten the processing time, the use of gelatin as a protective colloid, and a Farmer's solution to optimize the specificity of the technique.     

新疆10种沙生植物旱生结构的解剖学研究

新疆１０种沙生植物的形态解剖研究表明,它们为适应沙生环境形态结构发生变化。叶器官的形态呈三种类型：叶片退化成膜质或鳞片状,而由同化枝执行光合功能;叶片上下都具栅栏组织,表皮角质膜厚,表皮毛发达,气孔下陷,输导组织和机械组织都发达;叶片肉质化,叶肉组织不分化,贮水组织发达而输导组织不发达。轴器官中厚壁组织发达,围绕维管组织,维管组织内部也有发达的厚壁组织。根中普遍具有周皮,一些植物存在异常的维管组织,部分植物还具有粘液细胞或结晶。沙生植物形成各种旱生结构,以不同的方式适应沙生环境。     

大鼠烫伤后延髓孤束核β－内啡肽含量的变化及其抗血清的作用

大鼠背部２０％体表面积接触沸水２０ｓ,形成Ⅲ度烫伤后,延髓孤束核推挽灌流液中β－内啡肽免疫活性物质的含量显著升高,在烫后１、４ｈ两次达到峰值。烫后立即向弧束核微量注射０．４μｌβ－内啡肽抗血清（滴度１：３００００）,可在一定程度上改善心功能指标,延缓血压和心率的下降,但未能延长动物的存活时间。提示孤束核的β－内啡肽在烫伤休克的病理过程中起作用,其含量的过量升高有抑制心血管功能的作用,从而不利于烫伤休克的恢复。