我国和世蓝浆果的发展前景

蓝浆果是具独特保健作用、生食加工皆宜的适于我国红黄壤地区开发的新兴经济作物。通过对美国一些研究机构和苗圃的考察及参加在智利举行的第七届国际蓝浆果研讨会,对目前世界蓝浆果的发展状况、趋势及一些最新研究成果作了概述,对我国发展蓝浆果的前景、方向等进行了讨论。     

Fine genetic mapping and physical delimitation of the lesion mimic gene Spl11 to a 160-kb DNA segment of the rice genome

The rice lesion mimic mutant spl11 was previously found to confer broad-spectrum disease resistance to both Magnaporthe grisea and Xanthomonas oryzae pv. oryzae. To better understand the molecular basis underlying cell death and disease resistance in rice, a map-based cloning strategy has been employed to isolate Spl11. Five Spl11-linked RAPD markers were developed and four of them were mapped to rice chromosome 12. A high-resolution genetic map was developed using a segregating population consisting of 1138 lesion mimic individuals. Recombination suppression was observed in the vicinity of Spl11. Three molecular markers tightly linked to Spl11 were identified and used to screen a BAC library. A contig spanning the Spl11 locus was constructed and physical mapping delimited Spl11 to a 160-kb DNA segment within a single BAC clone. These results provide the essential information for the final isolation of this important gene in the rice defense pathway.     

Widespread occurrence and unexpected diversity of red-shifted chlorophyll producing cyanobacteria in humid subtropical forest ecosystems

Discovery of red-shifted chlorophyll d and f in cyanobacteria has opened up new avenues to estimate global carbon fixation driven by far-red light. Shaded habitats in humid subtropical forest ecosystems contain an increased proportion of far-red light components relative to residual white light. After an extensive survey of shaded ecosystems within subtropical forests, wide occurrence of red-shifted chlorophyll-producing cyanobacteria was demonstrated by isolated Chl f-producing and Chl d-containing cyanobacteria. Chl f-producing cyanobacteria were classified into the genera of Aphanocapsa and Chroococcidiopsis and two undescribed genera within Leptolyngbyaceae. Newly isolated Chl d-containing Acaryochloris sp. CCNUM4 showed the closest phylogenetic relationship with Acaryochloris species isolated from marine environments. Acaryochloris sp. CCNUM4 produced Chl d as major photopigment, and Chl f-producing cyanobacteria use Chl a under white light conditions but Chl a + f under far-red light conditions. Their habitats are widely distributed in subtropical forest ecosystems and varied from mosses on limestone to macrophyte and freshwater in the streams and ponds. This study presents a significant advance in the knowledge of distribution and diversity of red-shifted chlorophyll-producing cyanobacteria in terrestrial ecosystems. The results suggest that Chl f-producing and Chl d-containing cyanobacteria might be important primary producers in far-red light dominant niches worldwide.     

Recombination between Homologous Chromosomes Induced by Unrepaired UV-Generated DNA Damage Requires Mus81p and Is Suppressed by Mms2p

DNA lesions caused by UV radiation are highly recombinogenic. In wild-type cells, the recombinogenic effect of UV partially reflects the processing of UV-induced pyrimidine dimers into DNA gaps or breaks by the enzymes of the nucleotide excision repair (NER) pathway. In this study, we show that unprocessed pyrimidine dimers also potently induce recombination between homologs. In NER-deficient rad14 diploid strains, we demonstrate that unexcised pyrimidine dimers stimulate crossovers, noncrossovers, and break-induced replication events. The same dose of UV is about six-fold more recombinogenic in a repair-deficient strain than in a repair-proficient strain. We also examined the roles of several genes involved in the processing of UV-induced damage in NER-deficient cells. We found that the resolvase Mus81p is required for most of the UV-induced inter-homolog recombination events. This requirement likely reflects the Mus81p-associated cleavage of dimer-blocked replication forks. The error-free post-replication repair pathway mediated by Mms2p suppresses dimer-induced recombination between homologs, possibly by channeling replication-blocking lesions into recombination between sister chromatids.     

A Multicenter Study of Viral Aetiology of Community-Acquired Pneumonia in Hospitalized Children in Chinese Mainland

Virologica Sinica - Community-acquired pneumonia (CAP) is one of the leading causes of morbidity and mortality in children worldwide. In this study, we aimed to describe the aetiology of viral...     

Effect of dapagliflozin on diabetic patients with cardiovascular disease via MAPK signalling pathway

Clinical studies have shown that dapagliflozin can reduce cardiovascular outcome in patients with type 2 diabetes mellitus (T2DM), but the exact mechanism is unclear. In this study, we used the molecular docking and network pharmacology methods to explore the potential mechanism of dapagliflozin on T2DM complicated with cardiovascular diseases (CVD). Dapagliflozin's potential targets were predicted via the Swiss Target Prediction platform. The pathogenic targets of T2DM and CVD were screened by the Online Mendelian Inheritance in Man (OMIM) and Gene Cards databases. The common targets of dapagliflozin, T2DM and CVD were used to establish a protein-protein interaction (PPI) network; the potential protein functional modules in the PPI network were found out by MCODE. Metascape tool was used for Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis. A potential protein functional module with the best score was obtained from the PPI network and 9 targets in the protein functional module all showed good binding properties when docking with dapagliflozin. The results of KEGG pathway enrichment analysis showed that the underlying mechanism mainly involved AGE-RAGE signalling pathway in diabetic complications, TNF signalling pathway and MAPK signalling pathway. Significantly, the MAPK signalling pathway was considered as the key pathway. In conclusion, we speculated that dapagliflozin played a therapeutic role in T2DM complicated with CVD mainly through MAPK signalling pathway. This study preliminarily reveals the possible mechanism of dapagliflozin in the treatment of T2DM complicated with CVD and provides a theoretical basis for future clinical research.     

Increased ��-tocotrienol content in seeds of transgenic rice overexpressing Arabidopsis ��-tocopherol methyltransferase

Vitamin E comprises a group of eight lipid soluble antioxidant compounds that are an essential part of the human diet. The ??-isomers of both tocopherol and tocotrienol are generally considered to have the highest antioxidant activities. ??-tocopherol methyltransferase (??-TMT) catalyzes the final step in vitamin E biosynthesis, the methylation of ??- and ??-isomers to ??- and ??-isomers. In present study, the Arabidopsis ??-TMT (AtTMT) cDNA was overexpressed constitutively or in the endosperm of the elite japonica rice cultivar Wuyujing 3 (WY3) by Agrobacterium-mediated transformation. HPLC analysis showed that, in brown rice of the wild type or transgenic controls with empty vector, the ??-/??-tocotrienol ratio was only 0.7, much lower than that for tocopherol (~19.0). In transgenic rice overexpressing AtTMT driven by the constitutive Ubi promoter, most of the ??-isomers were converted to ??-isomers, especially the ??- and ??-tocotrienol levels were dramatically decreased. As a result, the ??-tocotrienol content was greatly increased in the transgenic seeds. Similarly, over-expression of AtTMT in the endosperm also resulted in an increase in the ??-tocotrienol content. The results showed that the ??-/??-tocopherol ratio also increased in the transgenic seeds, but there was no significant effect on ??-tocopherol level, which may reflect the fact that ??-tocopherol is present in very small amounts in wild type rice seeds. AtTMT overexpression had no effect on the absolute total content of either tocopherols or tocotrienols. Taken together, these results are the first demonstration that the overexpression of a foreign ??-TMT significantly shift the tocotrienol synthesis in rice, which is one of the world??s most important food crops.     

Cutaneous Papilloma and Squamous Cell Carcinoma Therapy Utilizing Nanosecond Pulsed Electric Fields (nsPEF)

Nanosecond pulsed electric fields (nsPEF) induce apoptotic pathways in human cancer cells. The potential therapeutic effective of nsPEF has been reported in cell lines and in xenograft animal tumor model. The present study investigated the ability of nsPEF to cause cancer cell death in vivo using carcinogen-induced animal tumor model, and the pulse duration of nsPEF was only 7 and 14 nano second (ns). An nsPEF generator as a prototype medical device was used in our studies, which is capable of delivering 7–30 nanosecond pulses at various programmable amplitudes and frequencies. Seven cutaneous squamous cell carcinoma cell lines and five other types of cancer cell lines were used to detect the effect of nsPEF in vitro. Rate of cell death in these 12 different cancer cell lines was dependent on nsPEF voltage and pulse number. To examine the effect of nsPEF in vivo, carcinogen-induced cutaneous papillomas and squamous cell carcinomas in mice were exposed to nsPEF with three pulse numbers (50, 200, and 400 pulses), two nominal electric fields (40 KV/cm and 31 KV/cm), and two pulse durations (7 ns and 14 ns). Carcinogen-induced cutaneous papillomas and squamous carcinomas were eliminated efficiently using one treatment of nsPEF with 14 ns duration pulses (33/39 = 85%), and all remaining lesions were eliminated after a 2nd treatment (6/39 = 15%). 13.5% of carcinogen-induced tumors (5 of 37) were eliminated using 7 ns duration pulses after one treatment of nsPEF. Associated with tumor lysis, expression of the anti-apoptotic proteins Bcl-xl and Bcl-2 were markedly reduced and apoptosis increased (TUNEL assay) after nsPEF treatment. nsPEF efficiently causes cell death in vitro and removes papillomas and squamous cell carcinoma in vivo from skin of mice. nsPEF has the therapeutic potential to remove human squamous carcinoma.