Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The Interna...Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Cancer Research has classified Helicobacter pylori as a Group 1 carcinogen. Materials and Methods: Drinking water samples from 20 cantons situated in areas of low and high incidence of gastric cancer in Costa Rica were analyzed. Water samples were concentrated and the nitrocellulose filter was cultivated for later molecular identification of Helicobacter pylori using the glmM marker. The tumor necrosis factor-alpha inducing protein (Tipalpha TNF-α) was used as a pathogenicity marker of the strains found followed by the sequencing of two products. Information on water management by aqueduct operators was collected in order to establish statistical relationships. Results: A total of 112 water samples were analyzed. Successful cultivation and molecular identification using the glmM marker was achieved in 39% of samples from areas of high incidence and in 7.5% of samples from areas of low incidence. Two glmM gene PCR products were sequenced and confirmed as true positives. Conclusions: The highest prevalence rate of Helicobacter pylori was found in water from areas with a high incidence of gastric cancer. Additionally, significant statistical correlations were established among environmental conditions, drinking water management and incidence of gastric cancer.展开更多
Generally disinfection of water at household level can be achieved using several soluble tablets or chemicals which have been proven to render water to be microbiologically safe. The use of disinfectants at household ...Generally disinfection of water at household level can be achieved using several soluble tablets or chemicals which have been proven to render water to be microbiologically safe. The use of disinfectants at household levels has been reported to contribute to the reduction of waterborne diseases in areas with limited supply of piped water. Water guard is produced and widely used in Tanzania especially in the rural and informal settlements;whilst in Namibia, water marker and Aqua tabs are imported and distributed to similar communities. Sodium Hypochlorite, a chlorine base chemical which is either in powder or tablet form is widely used in the two countries. Through informed consent community volunteers were used for the collection of water from shallow wells, which was subsequently treated and analysed in Tanzania. Volunteers were also asked about their methods of water treatment and storage. In Namibia, information on appropriate use of purification chemicals at household level was obtained through desktop review and key informants. The aim of this study was to investigate the effectiveness and proper utilisation of the water purification chemicals at household level in the two countries. The appropriate use of chemical doses provides 100% disinfection efficiency with chlorine residue of less than 0.3 mg/l which is within the recommended limits for WHO. The authors conclude that household water purification chemicals are effective against pathogens;however the chemicals’ effectiveness depends on appropriate use in terms of mixing, handling and hygiene of container used. A common problem experienced by Namibia and Tanzania is related to improper mixing, which affects the taste of water, and thus influences the user’s choice of prolonged use.展开更多
Near isogenic lines carrying large-effect QTL （qtl2.1）, which has a consistent influence on grain yield under upland drought stress conditions in a wide range of environments, were evaluated under water stress in th...Near isogenic lines carrying large-effect QTL （qtl2.1）, which has a consistent influence on grain yield under upland drought stress conditions in a wide range of environments, were evaluated under water stress in the fields. The line which gave higher yield under drought was crossed with a local elite line, PMK3, and forwarded to F2：3 generation. Significant variation was found among the F2：3 lines for agronomic traits under water stress in the fields. Low to high broad sense heritability （H） for investigated traits was also found. Water stress indicators such as leaf rolling and leaf drying were negatively correlated with plant height, biomass and grain yield under stress. Bulked segregant analysis （BSA） was performed with the markers in the vicinity of qUl2.1, and RM27933 was found to be segregated perfectly well in individual components of drought resistant and drought susceptible bulks which were bulked based on yield under water stress among F2：3 lines. Hence, this simple and breeder friendly marker, RM27933, may be useful as a potentially valuable candidate marker for the transfer of the QTL qtl12.1 in the regional breeding program. Bioinformatic analysis of the DNA sequence of the qtl12.1 region was also done to identify and analyze positional candidate genes associated with this QTL and to ascertain the putative molecular basis of qUl2.1.展开更多
Drought is a recurrent phenomenon in many of the countries. Moisture stress during seedling stage is very critical in determining the establishment of the crop and its further development and yield. Identifying drough...Drought is a recurrent phenomenon in many of the countries. Moisture stress during seedling stage is very critical in determining the establishment of the crop and its further development and yield. Identifying drought tolerance mechanism and physiological markers of drought susceptibility is this crop during seedling stress would be useful tool in future genetic manipulation programme to establish drought tolerance in this crop. Thus the present study aimed for quickly identifying reliable physiological markers for drought susceptibility through evaluation of physiological and biochemical changes in leaves of two contrasting mungbean (Vigna radiata L. Wilczek) cultivars i.e. K 851 (drought tolerant) and PDM 84-139 (drought susceptible) during seedling development. A range of four external water potentials (i.e. -1.0, -2.0, -3.0 and -4.0 bars), besides glass distilled water as control (0.0 bar), was used. Parameters like leaf area, relative leaf water content, chlorophyll content, chlorophyll stability indices in both the cultivars were decreased with the increasing magnitude of stress. By and large phenols and ascorbic acid content were increased with the stress level but the trend was not consistent. A steady rise in proline, hydrogen peroxide content and lipid peroxidation was found with water stress. Out of two cultivars tested, drought tolerant cultivar K 851 was better in leaf water balance and higher accumulation of phenols, proline and ascorbic acid than PDM 84-139. The correlation study indicated lipid peroxidation and H<sub>2</sub>O<sub>2</sub> content as valuable physiological markers for screening of drought susceptibility.展开更多
高水分利用效率(Water use efficiency,WUE)是丰产性和节水性的统一。为给小麦高WUE分子设计育种提供理论依据和技术支撑,利用与WUE相关QTLs紧密连锁的8个分子标记和与叶水势紧密连锁的2个分子标记,通过PCR技术检测了其在小麦进化种质...高水分利用效率(Water use efficiency,WUE)是丰产性和节水性的统一。为给小麦高WUE分子设计育种提供理论依据和技术支撑,利用与WUE相关QTLs紧密连锁的8个分子标记和与叶水势紧密连锁的2个分子标记,通过PCR技术检测了其在小麦进化种质、黄淮海麦区小麦品种(系)、高代小麦新品系和F1代共81份小麦随机材料中的分布。结果表明,在10份小麦进化种质中,有9个WUE相关分子标记的出现频率均高于70%。在27个黄淮海水旱地区代表品种(系)中,有7个WUE相关分子标记的出现频率高于85%。在44份高代品系和F1代中,有9个WUE相关分子标记的出现频率高于90%。在晋麦47×京东8号、济麦22×运旱22-23和济麦22×长6878杂交F1代中实现了WUE相关分子模块组装。在81份小麦随机材料中,有9个WUE相关标记的出现频率高于85%,说明这些分子标记能够稳定遗传,可用于小麦WUE分子标记辅助育种。展开更多
文摘Background: Most patients infected with Helicobacter pylori show no clinical symptoms. Nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Cancer Research has classified Helicobacter pylori as a Group 1 carcinogen. Materials and Methods: Drinking water samples from 20 cantons situated in areas of low and high incidence of gastric cancer in Costa Rica were analyzed. Water samples were concentrated and the nitrocellulose filter was cultivated for later molecular identification of Helicobacter pylori using the glmM marker. The tumor necrosis factor-alpha inducing protein (Tipalpha TNF-α) was used as a pathogenicity marker of the strains found followed by the sequencing of two products. Information on water management by aqueduct operators was collected in order to establish statistical relationships. Results: A total of 112 water samples were analyzed. Successful cultivation and molecular identification using the glmM marker was achieved in 39% of samples from areas of high incidence and in 7.5% of samples from areas of low incidence. Two glmM gene PCR products were sequenced and confirmed as true positives. Conclusions: The highest prevalence rate of Helicobacter pylori was found in water from areas with a high incidence of gastric cancer. Additionally, significant statistical correlations were established among environmental conditions, drinking water management and incidence of gastric cancer.
文摘Generally disinfection of water at household level can be achieved using several soluble tablets or chemicals which have been proven to render water to be microbiologically safe. The use of disinfectants at household levels has been reported to contribute to the reduction of waterborne diseases in areas with limited supply of piped water. Water guard is produced and widely used in Tanzania especially in the rural and informal settlements;whilst in Namibia, water marker and Aqua tabs are imported and distributed to similar communities. Sodium Hypochlorite, a chlorine base chemical which is either in powder or tablet form is widely used in the two countries. Through informed consent community volunteers were used for the collection of water from shallow wells, which was subsequently treated and analysed in Tanzania. Volunteers were also asked about their methods of water treatment and storage. In Namibia, information on appropriate use of purification chemicals at household level was obtained through desktop review and key informants. The aim of this study was to investigate the effectiveness and proper utilisation of the water purification chemicals at household level in the two countries. The appropriate use of chemical doses provides 100% disinfection efficiency with chlorine residue of less than 0.3 mg/l which is within the recommended limits for WHO. The authors conclude that household water purification chemicals are effective against pathogens;however the chemicals’ effectiveness depends on appropriate use in terms of mixing, handling and hygiene of container used. A common problem experienced by Namibia and Tanzania is related to improper mixing, which affects the taste of water, and thus influences the user’s choice of prolonged use.
基金funded by the Generation Challenge Programme Grant in coordination with the Global Partnership Initiative for Plant Breeding Capacity Building and Global Crop Diversity Trust
文摘Near isogenic lines carrying large-effect QTL （qtl2.1）, which has a consistent influence on grain yield under upland drought stress conditions in a wide range of environments, were evaluated under water stress in the fields. The line which gave higher yield under drought was crossed with a local elite line, PMK3, and forwarded to F2：3 generation. Significant variation was found among the F2：3 lines for agronomic traits under water stress in the fields. Low to high broad sense heritability （H） for investigated traits was also found. Water stress indicators such as leaf rolling and leaf drying were negatively correlated with plant height, biomass and grain yield under stress. Bulked segregant analysis （BSA） was performed with the markers in the vicinity of qUl2.1, and RM27933 was found to be segregated perfectly well in individual components of drought resistant and drought susceptible bulks which were bulked based on yield under water stress among F2：3 lines. Hence, this simple and breeder friendly marker, RM27933, may be useful as a potentially valuable candidate marker for the transfer of the QTL qtl12.1 in the regional breeding program. Bioinformatic analysis of the DNA sequence of the qtl12.1 region was also done to identify and analyze positional candidate genes associated with this QTL and to ascertain the putative molecular basis of qUl2.1.
文摘Drought is a recurrent phenomenon in many of the countries. Moisture stress during seedling stage is very critical in determining the establishment of the crop and its further development and yield. Identifying drought tolerance mechanism and physiological markers of drought susceptibility is this crop during seedling stress would be useful tool in future genetic manipulation programme to establish drought tolerance in this crop. Thus the present study aimed for quickly identifying reliable physiological markers for drought susceptibility through evaluation of physiological and biochemical changes in leaves of two contrasting mungbean (Vigna radiata L. Wilczek) cultivars i.e. K 851 (drought tolerant) and PDM 84-139 (drought susceptible) during seedling development. A range of four external water potentials (i.e. -1.0, -2.0, -3.0 and -4.0 bars), besides glass distilled water as control (0.0 bar), was used. Parameters like leaf area, relative leaf water content, chlorophyll content, chlorophyll stability indices in both the cultivars were decreased with the increasing magnitude of stress. By and large phenols and ascorbic acid content were increased with the stress level but the trend was not consistent. A steady rise in proline, hydrogen peroxide content and lipid peroxidation was found with water stress. Out of two cultivars tested, drought tolerant cultivar K 851 was better in leaf water balance and higher accumulation of phenols, proline and ascorbic acid than PDM 84-139. The correlation study indicated lipid peroxidation and H<sub>2</sub>O<sub>2</sub> content as valuable physiological markers for screening of drought susceptibility.
文摘高水分利用效率(Water use efficiency,WUE)是丰产性和节水性的统一。为给小麦高WUE分子设计育种提供理论依据和技术支撑,利用与WUE相关QTLs紧密连锁的8个分子标记和与叶水势紧密连锁的2个分子标记,通过PCR技术检测了其在小麦进化种质、黄淮海麦区小麦品种(系)、高代小麦新品系和F1代共81份小麦随机材料中的分布。结果表明,在10份小麦进化种质中,有9个WUE相关分子标记的出现频率均高于70%。在27个黄淮海水旱地区代表品种(系)中,有7个WUE相关分子标记的出现频率高于85%。在44份高代品系和F1代中,有9个WUE相关分子标记的出现频率高于90%。在晋麦47×京东8号、济麦22×运旱22-23和济麦22×长6878杂交F1代中实现了WUE相关分子模块组装。在81份小麦随机材料中,有9个WUE相关标记的出现频率高于85%,说明这些分子标记能够稳定遗传,可用于小麦WUE分子标记辅助育种。
