Nicotianamine,a Novel Enhancer of Rice Iron Bioavailability to Humans

Background

Polished rice is a staple food for over 50% of the world''s population, but contains little bioavailable iron (Fe) to meet human needs. Thus, biofortifying the rice grain with novel promoters or enhancers of Fe utilization would be one of the most effective strategies to prevent the high prevalence of Fe deficiency and iron deficiency anemia in the developing world.

Methodology/Principal Findings

We transformed an elite rice line cultivated in Southern China with the rice nicotianamine synthase gene (OsNAS1) fused to a rice glutelin promoter. Endosperm overexpression of OsNAS1 resulted in a significant increase in nicotianamine (NA) concentrations in both unpolished and polished grain. Bioavailability of Fe from the high NA grain, as measured by ferritin synthesis in an in vitro Caco-2 cell model that simulates the human digestive system, was twice as much as that of the control line. When added at 1∶1 molar ratio to ferrous Fe in the cell system, NA was twice as effective when compared to ascorbic acid (one of the most potent known enhancers of Fe bioavailability) in promoting more ferritin synthesis.

Conclusions

Our data demonstrated that NA is a novel and effective promoter of iron utilization. Biofortifying polished rice with this compound has great potential in combating global human iron deficiency in people dependent on rice for their sustenance.     

Solution structure of the severe acute respiratory syndrome-coronavirus heptad repeat 2 domain in the prefusion state

The envelope glycoprotein, termed the spike protein, of severe acute respiratory syndrome coronavirus (SARS-CoV) is known to mediate viral entry. Similar to other class 1 viral fusion proteins, the heptad repeat regions of SARS-CoV spike are thought to undergo conformational changes from a prefusion form to a subsequent post-fusion form that enables fusion of the viral and host membranes. Recently, the structure of a post-fusion form of SARS-CoV spike, which consists of isolated domains of heptad repeats 1 and 2 (HR1 and HR2), has been determined by x-ray crystallography. To date there is no structural information for the prefusion conformations of SARS-CoV HR1 and HR2. In this work we present the NMR structure of the HR2 domain (residues 1141-1193) from SARS-CoV (termed S2-HR2) in the presence of the co-solvent trifluoroethanol. We find that in the absence of HR1, S2-HR2 forms a coiled coil symmetric trimer with a complex molecular mass of 18 kDa. The S2-HR2 structure, which is the first example of the prefusion form of coronavirus envelope, supports the current model of viral membrane fusion and gives insight into the design of structure-based antagonists of SARS.     

壳聚糖固定化AS1．398中性蛋白酶稳定性的研究

对以壳聚糖为载体,由戊二醛作交联剂。制备的固定化ＡＳ１．３９８中性蛋白酶的稳定性进行了研究。实验结果表明,固定化ＡＳ１．３９８中性蛋白酶对热、乙醇、尿素以及ｐＨ值的稳定性均有明显的提高。     

QTL analysis of leaf morphology in tetraploid Gossypium (cotton)

Molecular markers were used to map and characterize quantitative trait loci (QTLs) determining cotton leaf morphology and other traits, in 180 F₂ plants from an interspecific cross between a Gossypium hirsutum genotype carrying four morphological mutants, and a wild-type Gossypium barbadense. The prominent effects of a single region of chromosome 15, presumably the classical ”Okra-leaf” locus, were modified by QTLs on several other chromosomes affecting leaf size and shape. For most traits, each parent contained some alleles with positive effects and others with negative effects, suggesting a large potential for adapting leaf size and shape to the needs of particular production regimes. Twenty one QTLs/loci were found for the morphological traits at LOD≥3.0 and P≤0.001, among which 14 (63.6%) mapped to D-subgenome chromosomes. Forty one more possible QTLs/loci were suggested with 2.0≤LOD<3.0 and 0.001<P≤0.01. Among all of the 62 possible QTLs (found at LOD≥2.0 and P≤0.01) for the 14 morphological traits in this study, 38 (61.3%) mapped to D-subgenome chromosomes. This reinforces the findings of several other studies in suggesting that the D-subgenome of tetraploid cotton has been subject to a relatively greater rate of evolution than the A-subgenome, subsequent to polyploid formation. Received: 26 April 1999 / Accepted: 30 July 1999     

Complete genome sequence of the bacterium Ketogulonicigenium vulgare Y25

Ketogulonicigenium vulgare is characterized by the efficient production of 2KGA from L-sorbose. Ketogulonicigenium vulgare Y25 is known as a 2-keto-L-gulonic acid-producing strain in the vitamin C industry. Here we report the finished, annotated genome sequence of Ketogulonicigenium vulgare Y25.     

Genetic Manipulation of Sex Ratio for the Large-Scale Breeding of YY Super-Male and XY All-Male Yellow Catfish (Pelteobagrus fulvidraco (Richardson))

Yellow catfish has become one of the most important freshwater aquaculture species in China. The mono-sex male yellow catfish has important application value in aquaculture because the male grows generally faster than the sibling females under the same conditions. This study has screened YY super-male and YY physiological female yellow catfish by sex reversal, gynogenesis, and progeny testing, which can help to achieve the large-scale production of YY super-male and XY all-male. From 2008 to 2010, about 123,000 YY super-male were produced, and about 81 million XY all-male fry were produced with 100 % male rate by random sampling. Therefore, these results indicate that YY super-male and YY physiological female yellow catfish can be viable and fertile. We conclude that the mono-sex breeding technique by YY super-male yellow catfish is stable and reliable, which has great potential for application in yellow catfish aquaculture.     

沙枣花蜜腺的发育解剖学研究

沙枣的花蜜腺位于花柱基部的筒状花盘上,属花盘蜜腺,其蜜腺位于花盘外方,由分履表皮和产蜜组织组成。分泌表皮具有角质层和变态的气孔器。产蜜组织在发育过程中,其液泡和淀粉粒都随着蜜腺的发育呈现一定的消长规律,最后形成的蜜汁由盘状蜜腺表面的气孔泌出。