Expression of mouse metallothionein-I gene confers cadmium resistance in transgenic tobacco plants

Transgenic tobacco plants containing a mouse metallothionein-I (MT-I) gene fused to the cauliflower mosaic virus 35S (CaMV 35S) promoter and nopaline synthase (nos) polyadenylation site were obtained by transforming tobacco leaf discs with an Agrobacterium tumefaciens strain carrying the chimaeric gene. Transformants were directly selected and rooted on medium containing cadmium and kanamycin. A total of 49 individual transgenic tobacco plants were regenerated. Among them 20% showed a very high expression level and their growth was unaffected by up to 200 M cadmium, whereas the growth of control plants was severely affected leaf chlorosis occurred on medium containing only 10 M cadmium. The concentration of MT-I in leaves of control and transgenic tobacco was determined with Cd/haemoglobin saturation assay, a polarographic method and western blotting. In addition, seeds from self-fertilized transgenic plants were germinated on medium containing toxic levels of cadmium and scored for tolerance/susceptibility to this heavy metal. The ratio of tolerant to susceptible plants was 3:1 indicating that the metallothionein gene is inherited as a single locus.     

Anthranilate synthase and chorismate mutase activities in transgenic tobacco plants overexpressing tryptophan decarboxylase fromCatharanthus roseus

TransgenicNicotiana tabacum L. Petit Havana SR1 F₁-plants expressing tryptophan decarboxylase cDNA (tdc) fromCatharanthus roseus (L.) G. Don under the control of the CaMV 35S promoter and terminator exhibited tryptophan decarboxylase (TDC) enzyme activity and accumulated tryptamine. The plants with the highest TDC activity contained 19 pkat per mg of protein. The influence of transgenic expression oftdc on the activities of anthranilate synthase (AS) and chorismate mutase (CM) were examined in 10 transgenic tobacco plants. The specific activities of these two chorismate-utilizing enzymes were not significantly affected by expression oftdc, despite their important functions as branch point enzymes in the shikimate pathway. The results indicate that the normal route of tryptophan biosynthesis in plants is sufficient to supply a considerable amount of this essential amino acid for the biosynthesis of secondary metabolites. Despite their increased tryptamine content, the growth and development of the transgenic tobacco plants expressingtdc appeared normal.     

394delTT: a Nordic cystic fibrosis mutation

In a systematic screening for mutations in the gene encoding the cystic fibrosis transmembrane regulator among Danish cystic fibrosis (CF) patients, we identified a mutation in exon 3 (394delTT); this mutation was found to be relatively common in Denmark. We therefore screened for 394delTT in Sweden and Norway, where it turned out to be the second most frequent mutation, accounting for 4% of all CF mutations. It also occurs with a high frequency in Finland, but has not been found in larger surveys of mutations in the CFTR gene. Thus, 394delTT seems to be a specific Nordic CF mutation.     

Systematic classification of Asian colobines

In order to study the differentiation of Asian colobines, fourteen variables were analysed in one way, on 123 skulls, includingRhinopithecus, Presbytis, Presbytiscus, Pygathrix, andNasalis with both cluster and differentiated functions tests. Information on paleoenvironment changes in China and South-East Asia since late Tertiary have been used to examine the influences of migratory habits and the distribution range in Asian colobines. The cladogram among different Asian colobines genera was made from the results of various analysis. Some new points or revisions were suggested: 1. Following the second migratory way, ancient species of Asian colobines perhaps passed through Xizang along the northern bank of Tethis sea and Heng-Duan Shan regions, across Yunnan into Vietnam, since the ancient continent between Yunnan and Xizang was already located in on eastern bank of Tethis sea. Thus, during the evolution, Asian colobines must have had two original centres, i.e. “Sundaland” and Heng-Duan Shan Chinese regions; 2. Pygatrix possesses a lot of cranial features more similar toPresbytiscus than toRhinopithecus. The small difference from the modification combinesPygatrix with other two genera as shown by Groves (1970), but it is better to putPygatrix andPresbytiscus together as one genus; 3.Nasalis (2n=48) may be the most primitive genus within Asian colobines. Some features shared withRhinopithecus, for example body size, terrestrial activities, limb proportion etc. ...seem to be considered as a common inheritance of symlesiomorphus characters; 4.Rhinopithecus, with reference to cranioface and cranium or to its origin, is a special genus of Asian colobine. It may represent the highest level of evolutionary position within various genera (Peng et al., 1985).     

Mother-cub relationships in giant pandas in the Qinling Mountains,China, with comment on rescuing abandoned cubs

Six cases of mother-cub relationships in wild giant pandas (Ailuropoda melanoleuca) were observed in the Qinling Mountains, China. It was found that panda cubs are normally left alone in the den for 4–8 h while mothers forage. The mother's absence during bouts of foraging should be considered when rescuing abandoned cubs in order to avoid adding to the decline of the wild population. © 1994 Wiley-Liss, Inc.     

Zn对细胞保护作用机理的研究

应用扫描质子微探针和同步辐射ｘ荧光分析技术测定了细胞中元素的分布和组成,为确定Zn是细胞结构成分提供了直接的实验依据.用上述核技术结合有关生化指标,分析测定了正常和损伤细胞（脂质过氧化损伤）中Fe,Zn和丙二醛、SH基含量变化的相互关系.实验结果表明,当细胞发生脂质过氧化损伤时,Fe含量和丙二醛含量同步增高,而Zn含量和SH基量则降低.给细胞补充Zn后,提高了细胞质膜中的Zn含量,SH基量也随之增加,同时丙二醛量降低.提示Zn保护细胞完整性的作用机理之一是控制脂质过氧化作用.Zn可保护膜蛋白的SH基,减少和阻止被Fe所催化的过氧化反应.     

Chromium-induced inhibition of ethylene evolution in bean (Phaseolus vulgaris) leaves

The influence of chromium concentration on ethylene production in bean plants ( Phaseolus vulgaris L. cv. Contender) was investigated. A Cr ion-induced inhibition of ethylene synthesis from endogenous 1-aminocyclopropane-1-carboxylic acid (ACC) was observed within both leaf discs floated on 2 m M CrO²⁻₄ or Cr³⁺ and leaf discs from plants cultured in nutrient solutions containing 10, 20 or 40 μ M CrO²⁻₄. However, Cr ions supplied either to plants with the nutrient solution or to discs with the incubation medium rather increased the conversion of exogenous ACC to ethylene. Primary leaves of plants exposed to CrO²⁻₄-containing nutrient solutions showed a statistically insignificant decrease of ACC-synthase activity. In the trifoliolate leaves of plants exposed to 10 μ M CrO²⁻₄, in which a significant decrease of ethylene production from endogenous ACC was observed, a substantial increase of ACC synthase was found. These results indicate that Cr ion-induced inhibition of ethylene production is not due to a breakdown of membrane integrity, which is necessary for ethylene forming enzyme activity, but caused by metabolic alterations leading to decreased ACC availability. Chromium ions may act by inhibiting ACC synthase activity or by diverting a metabolic step prior to the ACC synthase catalyzed reaction.     

Plant regeneration through culture of isolated microspores of Triticum aestivum L.

Wheat microspores mechanically isolated from the anthers before culture and isolated from the anthers during the hole culture period in a chemically defined medium resulted in proembryos, embryos and finally plants. Of the four genotypes included, all responded with proembryos, and the two spring wheats Ciano and Walter gave rise to macroscopic embryos and plants. The frequency of embryo regeneration and the frequency of albino plants in both Ciano and Walter was in accordance with previously obtained results with anther culture derived material.Abbreviations 2,4-d 2,4-dichlorophenoxy acetic acid - NAA 1-naphthaleneacetic acid     

Trace elements in hair of blackfoot disease

Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Though extensive epidemiological study has implicated that high arsenic content in artesian well water of the endemic area, bears some important connection with the disease, the etiology of the disease is still unknown. In this study, attention is paid to multielement determination in order to find out whether the trace elements in hair of Blackfoot disease patients are different from those of the controls. Experimental results indicate that the concentrations of As and Se in hair of patients are significantly higher than those of the controls, but Ca and Zn are significantly lower than those of the controls. The possible connection of these elements with the etiology of the disease is discussed.     

The 28 kDa apoprotein of CP 26 in PS II binds copper

Photosystem II (PS II) particles isolated from spinach in the presence of 10 M CuSO₄ contained 1.2 copper/300 Chl that was resistant to EDTA. When CuSO₄ was not added during the isolation, PS II particles contained variable amounts of copper resistant to EDTA (0.1–1.1 copper/300 Chl). No correlation was found between copper content and oxygen evolving capacity of the PS II particles. To identify the copper binding protein, we developed a fractionation procedure which included solubilisation of PS II particles followed by precipitation with polyethylene glycol. A 22-fold purification of copper with respect to protein was achieved for a 28 kDa protein. Partial amino acid sequence of a 13 kDa fragment, obtained after V8 (endo Glu-C) protease treatment, showed identity with CP 26 over a 14 amino acid stretch. EPR measurements on the purified protein suggest oxygen and/or nitrogen as ligands for copper but tend to exclude sulfur. We conclude that the 28 kDa apoprotein of CP 26 from spinach binds one copper per molecule of CP 26. A possible function for this copper protein in the xanthophyll cycle is discussed.Abbreviations CP 26 and CP 29 chlorophyll a/b protein complex 26 and 29 - LHC II light-harvesting chlorophyll a/b protein complex of Photosystem II - SB14 sulfobetaine 14 A preliminary report of these results was presented at the IX Int. Congress on Photosynthesis, Nagoya, Japan, 1992.