Factors associated with spatial distribution of severe fever with thrombocytopenia syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) was firstly identified in mainland China in 2009 and the geographic distribution has expanded in recent years. In this study, we constructed ecological niche models (ENM) of SFTS with meteorological factors, environmental factor, and density of domestic animals using MaxEnt. We found four significant associated factors including altitude, yearly average temperature, yearly accumulated precipitation, and yearly average relative humidity which accounted for 94.1% percent contribution. SFTS occurrence probability was high when altitude was between -100 m and 100 m, and the probability was nearly 0 when altitude was beyond 3000 m. Response curves of SFTS to the yearly average temperature, yearly accumulated precipitation, and yearly average relative humidity were all reversed V-shape. SFTS occurrence probability was high where the yearly average temperature, yearly accumulated precipitation, and yearly relative humidity were 12.5-17.5 °C, 700-2250 mm and 63-82%, respectively. ENMs predicted that the potential high-risk areas were mainly distributed in eastern areas and central areas of China. But there were some predicted potential high-risk areas where no SFTS case was reported up to date. More researches should be done to make clear whether SFTS case had occurred in these areas.

Protective role of exogenous nitric oxide against oxidative-stress induced by salt stress in barley (Hordeum vulgare).

To probe into the potential of relieving the oxidative damage of salt stress, we investigated the protective role of nitric oxide on barley under salt stress. Salt stress resulted in increased ion leakage, lipid peroxidation and protein oxidation in barley leaves. Simultaneous treatments of barley leaves with 50 microM sodium nitroprusside, a nitric oxide donor, alleviated the damage of salt stress, reflected by decreased ion leakage, and malendialdehyde (MDA), carbonyl, and hydrogen peroxide content in barley leaves. The presence of the nitric oxide donor increased the activities of superoxide dismutases (SOD), ascorbate peroxidases (APX), and catalases (CAT). Meantime, sodium nitroprusside addition increased accumulation of ferritin at the protein level, indicating that nitric oxide directly regulated ferritin accumulation. These results suggested that nitric oxide can effectively protect seedlings from salt stress damage by enhancing activities of antioxidant enzymes to quench the excessive reactive oxygen species caused by salt stress and inducing the increase of ferritin accumulation to chelate larger number of ferrous ion. Information from this study can be used to improve soil management practices for sustainable use of salt-affected soils in the future.

[Effects of antisense-thioredoxin s gene on expression of endogenous thioredoxin h gene in transgenic wheat seed].

To clarify the function mechanism of antisense-thioredoxin s (anti-trxs) gene in transgenic wheat, the expression pattern of endogenous trxh gene in transgenic line 01TY70-1-17-5 and non-transgenic cultivar 'Yumai 70' were detected by semi-quantitative RT-PCR using wheat actin gene as the endogenous control. The results of analysis of transgenic and non-transgenic seeds in different maturation periods, different tissues and different germinating processes indicated that the mRNA transcript amounts of trxh gene in transgenic line seed were lowered distinctly, though the trxh gene mRNA transcript level varied greatly in different developing and germination stages. The mRNA transcript amounts of trxh gene in transgenic line seed were significantly lower than the control seeds by 20.1% 15-30 d after anthesis. The lowest mRNA transcript amount of trxh gene appeared at 25 day after fluorescence and the difference was significant at the 0.05 level. The analysis of gene expression in different tissues also indicated that the transcript levels of trxh gene in transgenic seed were significantly lower than control seeds in 25 d and 30 d after anthesis. The lowest amounts of mRNA transcript of trxh gene was from the endosperm 25 d after anthesis followed by embryo and then by whole seed. During seed germination, the mRNA transcript amounts of trxh gene in transgenic seed were lower than control seed after imbibing 24 h, but the difference was not significant. The above result demonstrated that foreign antisense trxs gene directly interferes with the expression of the endogenous gene.

Changes in proteins within germinating seeds of transgenic wheat with an antisense construct directed against the thioredoxin.

Thioredoxin h is closely related to germination of cereal seeds. The mechanism of transgenic wheat seeds with antisense trxs gene, which is responsible for low germination rate was studied through analyzing the changes in proteins of wheat seeds during germination. The antisense trxs could weaken the metabolism of wheat seeds by decreasing the quantity of proteins involved in metabolism, while chloroform-methanol (CM) protein fraction consisted mostly of some low molecular weight proteins (<20 kD). Compared with wild-type wheat seeds, the folding of glutenin in transgenic wheat ones was affected during the wheat maturating. Big glutenin macropolymers could be formed more easily in transgenic wheat seeds than in wild-type wheat ones. Therefore, the degradation speed of glutenin in transgenic wheat seeds was slower than that in wild-type wheat ones during seed germination. In addition, the degradation of some proteins in transgenic wheat embryos was also delayed during germination.

Transgenic barley with overexpressed PTrx increases aluminum resistance in roots during germination.

A transgenic barley line (LSY-11-1-1) with overexpressed Phalaris coerulescens thioredoxin gene (PTrx) was employed to measure the growth, protein oxidation, cell viability, and antioxidase activity in barley roots during germination on the presence of 2 mmol/L AlCl(3) on filter paper. The results show that (1) compared with the non-transgenic barley, LSY-11-1-1 had enhanced root growth, although both were seriously inhibited after AlCl(3) treatment; (2) the degree of protein oxidation and loss of cell viability in roots of LSY-11-1-1 were much less than those in roots of non-transgenic barley, as reflected by lower contents of protein carbonyl and Evans blue uptakes in LSY-11-1-1; (3) activities of catalase (CAT), glutathione peroxidase (GPX), ascorbate peroxidase (APX), and glutathione reductase (GR) in LSY-11-1-1 root tips were generally higher than those in non-transgenic barley root tips, although these antioxidase activities gave a rise to different degrees in both LSY-11-1-1 and non-transgenic barley under aluminum stress. These results indicate that overexpressing PTrx could efficiently protect barley roots from oxidative injury by increasing antioxidase activity, thereby quenching ROS caused by AlCl(3) during germination. These properties raise the possibility that transgenic barley with overexpressed PTrx may be used to reduce the aluminum toxicity in acid soils.

The level of expression of thioredoxin is linked to fundamental properties and applications of wheat seeds.

Work with cereals (barley and wheat) and a legume (Medicago truncatula) has established thioredoxin h (Trx h) as a central regulatory protein of seeds. Trx h acts by reducing disulfide (S-S) groups of diverse seed proteins (storage proteins, enzymes, and enzyme inhibitors), thereby facilitating germination. Early in vitro protein studies were complemented with experiments in which barley seeds with Trx h overexpressed in the endosperm showed accelerated germination and early or enhanced expression of associated enzymes (alpha-amylase and pullulanase). The current study extends the transgenic work to wheat. Two approaches were followed to alter the expression of Trx h genes in the endosperm: (1) a hordein promoter and its protein body targeting sequence led to overexpression of Trx h5, and (2) an antisense construct of Trx h9 resulted in cytosolic underexpression of that gene (Arabidopsis designation). Underexpression of Trx h9 led to effects opposite to those observed for overexpression Trx h5 in barley-retardation of germination and delayed or reduced expression of associated enzymes. Similar enzyme changes were observed in developing seeds. The wheat lines with underexpressed Trx showed delayed preharvest sprouting when grown in the greenhouse or field without a decrease in final yield. Wheat with overexpressed Trx h5 showed changes commensurate with earlier in vitro work: increased solubility of disulfide proteins and lower allergenicity of the gliadin fraction. The results are further evidence that the level of Trx h in cereal endosperm determines fundamental properties as well as potential applications of the seed.

[Study on molecular identification and pre-harvest sprouting characteristic of the transgenic anti-trxs-gene wheat line 00T89].

Pre-harvest sprouting of wheat is caused by a series of enzymes, in which alpha-amylase plays a key role. Thioredoxin (trx) is an important protein capable of reducing S-S to -SH. The authors transferred the anti-trxs gene into wheat ( Triticum aestivum L.) cultivar Wanmai 48 in 2000 in order to obtain a transgenic line with low activities of trx and alpha-amylase in wheat seeds to enhance their resistance to pre-harvest sprouting. In this work, a pair of specific anti-trxs primers were used in PCR test to validate the transgenic plants in T4 lines. A pair of primers of a wheat actin gene cDNA and a pair of trxs gene primers were used in the reverse transcription PCR test to measure the relative content of trx mRNA in the transgenic positive lines. The experiments of pre-harvest sprouting were carried out to test the resistance to pre-harvest sprouting. The results showed that there were 13 positive lines with the anti-trxs gene among 18 transgenic lines. In the maturity stage, the 8 relative contents of the trx mRNA in the 13 positive lines were reduced evidently (P < 0.01). The trx mRNA was correlated with the sprouting parameters significantly (r = 0.7181) . 6 lines with low trx mRNA showed stronger resistance to pre-harvest sprouting during the period from 30 days after anthesis to 10 days after maturity. Compared with non-transgenic plant (Wanmai 48, CK), the average sprouting time of these lines was postponed by 2.7 days (P < 0.01), the sprouting ratio of seeds on spikes and the spike sprouting degree were reduced by 35.5% (P < 0.01) and 47.5% (P < 0.01), respectively. However, 25 days after maturity, the sprouting capacity of the positive lines recovered gradually, and no significant differences were found between them (P > 0.05) . Thus, it can be concluded that the wheat pre-sprouting was controlled effectively in some 00T89 transgenic lines as a result of the expression of anti-trxs gene.