Fine mapping and candidate gene analysis of LM3, a novel lesion mimic gene in rice

A rice lesion mimic mutant, lm3, was obtained by the mutagenesis of an indica cultivar, 93-11, using γ-ray radiation. Brownish lesions appeared on the leaves of lm3 at the young seedling stage and persisted until the ripening stage. The lm3 mutant was characterised by a shorter plant height and delayed heading compared with the wild-type 93-11. A genetic analysis indicated that the lesion mimic phenotype was controlled by a single recessive gene. Using simple sequence repeat (SSR) markers, the target gene LM3 was first located between marker RM5748 and RM14906 on chromosome 3. We then developed Insertion-Deletion (InDel) markers to fine-map LM3, and the locus was localised to a 29 kb region defined by two InDel markers, In12571 and In12600. Five ORFs were predicted in the candidate region, and DNA sequencing detected a single-nucleotide polymorphism (SNP) in the coding region of LOC Os03g21900. The SNP in the fourth exon (C in 93-11; T in lm3) of LOC_Os03g21900 results in the substitution of a proline (P) with a serine (S) at the 140^th amino acid of the deduced uroporphyrinogen decarboxylase protein. We did not detect polymorphisms in the other predicted ORF regions between lm3 and 93-11. These results suggest that LOC_Os03g21900 is the most likely candidate gene for LM3.     

Dynamic Changes in Endothelial Cell Adhesion Molecule Nepmucin/CD300LG Expression under Physiological and Pathological Conditions

Vascular endothelial cells often change their phenotype to adapt to their local microenvironment. Here we report that the vascular endothelial adhesion molecule nepmucin/CD300LG, which is implicated in lymphocyte binding and transmigration, shows unique expression patterns in the microvascular endothelial cells of different tissues. Under physiological conditions, nepmucin/CD300LG was constitutively and selectively expressed at the luminal surface of the small arterioles, venules, and capillaries of most tissues, but it was only weakly expressed in the microvessels of the splenic red pulp and thymic medulla. Furthermore, it was barely detectable in immunologically privileged sites such as the brain, testis, and uterus. The nepmucin/CD300LG expression rapidly decreased in lymph nodes receiving acute inflammatory signals, and this loss was mediated at least in part by TNF-α. It was also down-regulated in tumors and tumor-draining lymph nodes, indicating that nepmucin/CD300LG expression is negatively regulated by locally produced signals under these circumstances. In contrast, nepmucin/CD300LG was induced in the high endothelial venule-like blood vessels of chronically inflamed pancreatic islets in an animal model of non-obese diabetes. Interestingly, the activated CD4⁺ T cells infiltrating the inflamed pancreas expressed high levels of the nepmucin/CD300LG ligand(s), supporting the idea that nepmucin/CD300LG and its ligand interactions are locally involved in pathological T cell trafficking. Taken together, these observations indicate that the nepmucin/CD300LG expression in microvascular endothelial cells is influenced by factor(s) that are locally produced in tissues, and that its expression is closely correlated with the level of leukocyte infiltration in certain tissues.     

Identification of a novel COL4A5 mutation in the proband initially diagnosed as IgAN from a Chinese family with X-linked Alport syndrome

Alport syndrome(AS) is a hereditary progressive nephropathy characterized by hematuria, ultrastructural lesions of the glomerular basement membrane, ocular lesions and sensorineural hearing loss. Germline mutations of COL4 A5 are associated with X-linked AS with an extreme phenotypic heterogeneity. Here, we investigated a Chinese family with Alport syndrome. The proband was a 9-year-old boy with hematuria and proteinuria. Based on the test results of renal biopsy and immunofluorescence,the proband was initially diagnosed as Ig A nephropathy and the treatment was recommended accordingly. Meanwhile, we found that the treatment outcome was poor. Therefore, for proper clinical diagnosis and appropriate treatment, targeted exome-based next-generation sequencing has been undertaken. We identified a novel hemizygous single nucleotide deletion c.1902 del A in COL4 A5 gene. Segregation analysis identified that this novel mutation is co-segregated among the affected family members but absent in unaffected family members. The clinical diagnosis of the proband was revised as AS accompanied by Ig A nephropathy,which has been rarely reported. Our findings demonstrated the significance of the application of Genetic screening, expanded the mutation spectrum of COL4 A5 associated AS patients with atypical renal phenotypes and provided a good lesson to be learned from our detour during the diagnosis.     

Singlet oxygen generation from the decomposition of alpha-linolenic acid hydroperoxide by cytochrome c and lactoperoxidase

Generation of singlet oxygen is first investigated in the decomposition of polyunsaturated lipid peroxide, alpha-linolenic acid hydroperoxide (LAOOH), by heme-proteins such as cytochrome c and lactoperoxidase. Chemiluminescence and electron spin resonance methods are used to confirm the singlet oxygen generation and quantify its yield. Decomposition products of LAOOH are characterized by HPLC-ESI-MS, which suggests that singlet oxygen is produced via the decomposition of a linear tetraoxide intermediate (Russell's mechanism). Free radicals formed in the decomposition are also identified by the electron spin resonance technique, and the results show that peroxyl, alkyl, and epoxyalkyl radicals are involved. The changes of cytochrome c and lactoperoxidase in the reaction are monitored by UV-visible spectroscopy, revealing the action of a monoelectronic and two-electronic oxidation for cytochrome c and lactoperoxidase, respectively. These results suggest that cytochrome c causes a homolytic reaction of LAOOH, generating alkoxyl radical and then peroxyl radical, which in turn releases singlet oxygen following the Russell mechanism, whereas lactoperoxidase leads to a heterolytic reaction of LAOOH, and the resulting ferryl porphyryl radical of lactoperoxidase abstracts the hydrogen atom from LAOOH to give peroxyl radical and then singlet oxygen. This observation would be important for a better understanding of the damage mechanism of cell membrane or lipoprotein by singlet oxygen and various radicals generated in the peroxidation and decomposition of lipids induced by heme-proteins.     

A trifluoromethyl substituted organoimido derivative of the hexametalate cluster: synthesis, crystal structure and bioactivity of [Mo6O17(NAr)2]2- (Ar=o-CF3C6H4)

The hexamolybdate cluster has been functionalized with fluorine-containing aromatic amine by the DCC (N,N'-dicyclohexylcarbodiimide) dehydrating protocol and a novel bifunctionalized arylimido derivative of hexamolybdate bearing the electron-withdrawing trifluoromethyl group, (Bu(4)N)(2)[Mo(6)O(17)(NAr)(2)] (Ar=o-CF(3)C(6)H(4)), has been prepared. Complete assignments were achieved for the title compound by elemental analysis, IR, (1)H NMR, UV/visible and single-crystal X-ray diffraction analyses. The preliminary agricultural biological activity test indicated that it has some herbicidal and insecticidal activities.     

Coexpression of the High Molecular Weight Glutenin Subunit 1Ax1 and Puroindoline Improves Dough Mixing Properties in Durum Wheat (Triticum turgidum L. ssp. durum)

Wheat end-use quality mainly derives from two interrelated characteristics: the compositions of gluten proteins and grain hardness. The composition of gluten proteins determines dough rheological properties and thus confers the unique viscoelastic property on dough. One group of gluten proteins, high molecular weight glutenin subunits (HMW-GS), plays an important role in dough functional properties. On the other hand, grain hardness, which influences the milling process of flour, is controlled by Puroindoline a (Pina) and Puroindoline b (Pinb) genes. However, little is known about the combined effects of HMW-GS and PINs on dough functional properties. In this study, we crossed a Pina-expressing transgenic line with a 1Ax1-expressing line of durum wheat and screened out lines coexpressing 1Ax1 and Pina or lines expressing either 1Ax1 or Pina. Dough mixing analysis of these lines demonstrated that expression of 1Ax1 improved both dough strength and over-mixing tolerance, while expression of PINA detrimentally affected the dough resistance to extension. In lines coexpressing 1Ax1 and Pina, faster hydration of flour during mixing was observed possibly due to the lower water absorption and damaged starch caused by PINA expression. In addition, expression of 1Ax1 appeared to compensate the detrimental effect of PINA on dough resistance to extension. Consequently, coexpression of 1Ax1 and PINA in durum wheat had combined effects on dough mixing behaviors with a better dough strength and resistance to extension than those from lines expressing either 1Ax1 or Pina. The results in our study suggest that simultaneous modulation of dough strength and grain hardness in durum wheat could significantly improve its breadmaking quality and may not even impair its pastamaking potential. Therefore, coexpression of 1Ax1 and PINA in durum wheat has useful implications for breeding durum wheat with dual functionality (for pasta and bread) and may improve the economic values of durum wheat.     

氮磷肥配施对苦荞根系生理生态及产量的影响

以苦荞品种‘迪庆’为材料,在盆栽试验条件下,研究了氮(纯氮用量分别为0g/kg、0.1g/kg、0.2g/kg)、磷(P2O5用量分别为0.1g/kg和0.2g/kg)配施对苦荞根系生长、生理指标及其产量的影响,旨在为黄土高原苦荞高产优质栽培提供理论依据。结果表明:(1)在相同施磷量条件下,苦荞幼苗的株高、茎粗、茎叶干重、主根长、根表面积、根系体积、根系直径、根系干重以及壮苗指数等均随施氮量的增加而呈先升后降的趋势,但根冠比随施氮量的增加而呈先降后升的趋势;叶片叶绿素含量以及根系活力、酸性磷酸酶(Apase)活性、可溶性蛋白含量和植株氮积累量随施氮量的增加呈抛物线变化趋势,根系硝酸还原酶(NR)活性和植株氮含量随施氮量的增加而增加;而根系可溶性糖含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量和游离脯氨酸含量等指标均随施氮量的增加而呈先降后升的趋势,0.1g/kg施氮处理各指标均显著低于其他处理;成熟期单株粒重、百粒重随施氮量的增加呈先升后降的趋势,0.1g/kg施氮处理各指标均显著高于其他处理。(2)在相同施氮量条件下,随着施磷量的增加,苦荞根系酸性磷酸酶(Apase)活性、SOD活性、POD活性、MDA含量、可溶性糖含量、可溶性蛋白以及游离脯氨酸含量等指标均降低,其余各指标则呈增加趋势。(3)无论施磷量条件如何,0.1g/kg的施氮处理下苦荞产量最高,与其他施氮处理相比,在低磷和高磷处理下的增产幅度分别为7.04%~37.40%和14.73%~68.26%;在施氮量一定的情况下,高磷处理比低磷处理增产15.96%~42.00%。(4)在该试验条件下,适当的氮磷肥配施表现出了明显的正加和效应,但过量施肥也有可能导致增产幅度下降,中氮高磷(施纯N量0.1g/kg,施P2O5量0.2g/kg)配施效果最优。