Potential use of cucumber (Cucumis sativus L.) endophytic fungi as seed treatment agents against root-knot nematode Meloidogyne incognita

Seed treatment with endophytic fungi has been regarded as an effective method for plant parasitic nematode control. Endophytic fungi from cucumber seedlings were isolated and screened for their potential to be used as seed treatment agents against Meloidogyne incognita. Among the 294 isolates screened, 23 significantly reduced galls formed by M. incognita in greenhouse test. The 10 most effective isolates were Fusarium (5), Trichoderma (1), Chaetomium (1), Acremonium (1), Paecilomyces (1), and Phyllosticta (1). Their control efficacies were repeatedly tested and their colonizations as well as in vitro activity against M. incognita were studied. They reduced the number of galls by 24.0%–58.4% in the first screening and 15.6%–44.3% in the repeated test, respectively. Phyllosticta Ph511 and Chaetomium Ch1001 had high colonizations on both the roots and the aboveground parts of cucumber seedlings. Fusarium isolates had colonization preference on the roots, their root colonizations ranging from 20.1% to 47.3% of the total root area. Trichoderma Tr882, Paecilomyces Pa972, and Acremonium Ac985 had low colonizations on both the roots and the aboveground parts. Acremonium Ac985, Chaetomium Ch1001, Paecilomyces Pa972, and Phyllosticta Ph511 produced compounds affecting motility of the second stage juveniles of M. incognita. Based on these results, Chaetomium Ch1001 was considered to have the highest potential as a seed treatment agent for M. incognita biocontrol.     

Investigation of the association between all-trans-retinol dehydrogenase (RDH8) polymorphisms and high myopia in Chinese

Retinoic acid level in the retina/choroid is altered in induced myopia models. All-trans-retinol dehydrogenase (RDH8) is an important enzyme of retinoic acid metabolism. This study aimed to investigate the association of the RDH8 gene with high myopia. Three single nucleotide polymorphisms (SNPs) [RDH851 (rs2233789), RDH8E5a (rs1644731), and RDH855b (rs3760753)] were selected, based on the linkage disequilibrium pattern of RDH8 from a previous study, and genotyped for 160 Han Chinese nuclear families with highly myopic (−10 diopters or worse) offspring as well as in an independent group with 166 highly myopic cases (−10 diopters or worse) and 211 controls. Family-based association analysis was performed using the family-based association test (FBAT) package, and genotype relative risk (GRR) was calculated using the GenAssoc program. Population-based association analysis was performed using Chi-square test. These SNPs were in linkage equilibrium with each other. SNPs RDH851 (rs2233789) and RDH8E5a (rs1644731) both did not show association with high myopia. SNP RDH855b (rs3760753) demonstrated significant association (P=0.0269) with a GRR of 0.543 (95% confidence interval=0.304–0.968, P=0.038). The association became statistically insignificant, however, after multiple comparison correction. Haplotype analysis did not show a significant association either. Population-based association analysis also showed no significant association (P>0.05). Our family- and population-based data both suggest that the RDH8 gene is unlikely to be associated with high myopia in Chinese.     

Establishment of an in vitro micropropagation protocol for Boscia senegalensis (Pers.) Lam. ex Poir

This report describes in vitro micropropagation of Boscia senegalensis, so-called famine foods, that helped the people in Darfur and Kordofan, Sudan survive during the 1984–1985 famine. Four types of explants prepared from green mature zygotic embryos were cultured on Murashige and Skoog (MS) medium augmented with 1–5 mg/L 6-benzyladenine (BA). The highest number of shoots per explant (14.3±0.9) was achieved on MS medium supplemented with 3 mg/L BA, while the highest shoot length [(3.5±0.4) cm] was obtained with 1 mg/L BA. The shoot cluster, when subcultured to its same medium, significantly increased the rate of shoot multiplication by the end of the third subculture. The maximum mean number of shoots per explant (86.5±3.6) was produced after three multiplication cycles on 3 mg/L BA-supplemented medium. In vitro induced shoots were excised and rooted on half strength MS medium fortified with 0.25 mg/L indole-3-butyric acid (IBA) to obtain complete plantlets. B. senegalensis-regenerated plantlets obtained in vitro for the first time, were hardened and 95% survived under greenhouse conditions.     

Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)

The effects of CO₂ enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassica alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height, stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO₂ concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem, 11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO₂ concentration, N concentration, and CO₂×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO₂. However, at 20 mmol N/L, elevated CO₂ had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO₂ concentration in the three N treatments, resulting in changes in the C/N and N/S ratios. Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO₂ concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO₂ condition. Project (No. 2007CB109305) supported by the National Basic Research Program (973) of China     

An Arabidopsis mutant atcsr-2 exhibits high cadmium stress sensitivity involved in the restriction of H2S emission

The gene AtCSR encodes peptidyl-prolyl cis/trans isomerases (PPIases) that accelerate energetically unfavorable cis/trans isomerization of the peptide bond preceding proline production.In our studies,we found that AtCSR was associated with cadmium (Cd)-sensitive response in Arabidopsis.Our results show that AtCSR expression was triggered by Cd-stress in wild type Arabidopsis.The expression of some genes responsible for Cd2+ transportation into vacuoles was induced,and the expression of the iron-regulated transporter 1 (IRT1) related to Cd2+ absorption from the environment was not induced in wild type with Cd2+ treatment.The expression of Cd-transportation related genes was not in response to Cd-stress,whereas IRT expression increased dramatically in atcsr-2 with Cd2+ treatment.The expression of glutathione 1 (GSH1) was consistent with GSH being much lower in atcsr-2 in comparison with the wild type with Cd2+ treatment.Additionally,malondialdehyde (MDA),hydrogen peroxide,and Cd2+ contents,and activities of some antioxidative enzymes,differed between the wild type and atcsr-2.Hydrogen sulfide (H2S) has been confirmed as the third gas-transmitter over recent years.The findings revealed that the expression pattern of H2 S-releasing related genes and that of Cd-induced chelation and transportation genes matched well in the wild type and atcsr-2,and H2S could regulate the expression of the Cd-induced genes and alleviate Cd-triggered toxicity.Finally,one possible suggestion was given:down-regulation of atcsr-2,depending on H2S gas-transmitter not only weakened Cd2+ chelation,but also reduced Cd2+ transportation into vacuoles,as well as enhancing the Cd2+ assimilation,thus rendering atcsr-2 mutant sensitive to Cd-stress.     

Association of CASP9, CASP10 gene polymorphisms and tea drinking with colorectal cancer risk in the Han Chinese population

The initiators caspase-9(CASP9) and caspase-10(CASP10) are two key controllers of apoptosis and play important roles in carcinogenesis.This study aims to explore the association between CASPs gene polymorphisms and colorectal cancer(CRC) susceptibility in a population-based study.A two-stage designed population-based case-control study was carried out,including a testing set with 300 cases and 296 controls and a validation set with 206 cases and 845 controls.A total of eight tag selected single nucleotide polymorphisms(SNPs) in CASP9 and CASP10 were chosen based on HapMap and the National Center of Biotechnology Information(NCBI) datasets and genotyped by restriction fragment length polymorphism(RFLP) assay.Multivariate logistic regression models were applied to evaluate the association of SNPs with CRC risk.In the first stage,from eight tag SNPs,three polymorphisms rs4646077(odds ratio(OR) AA+AG:0.654,95% confidence interval(CI):0.406-1.055;P=0.082),rs4233532(OR CC:1.667,95% CI:0.967-2.876;OR CT:1.435,95% CI:0.998-2.063;P=0.077),and rs2881930(OR CC:0.263,95% CI:0.095-0.728,P=0.036) showed possible association with CRC risk.However,none of the three SNPs,rs4646077(OR AA+AG:1.233,95% CI:0.903-1.683),rs4233532(OR CC:0.892,95% CI:0.640-1.243;OR CT:1.134,95% CI:0.897-1.433),and rs2881930(OR CC:1.096,95% CI:0.620-1.938;OR CT:1.009,95% CI:0.801-1.271),remained significant with CRC risk in the validation set,even after stratification for different tumor locations(colon or rectum).In addition,never tea drinking was associated with a significantly increased risk of CRC in testing set together with validation set(OR:1.755,95% CI:1.319-2.334).Our results found that polymorphisms of CASP9 and CASP10 genes may not contribute to CRC risk in Chinese population and thereby the large-scale case-control studies might be in consideration.In addition,tea drinking was a protective factor for CRC.     

Effects of elevated CO(2) levels on root morphological traits and Cd uptakes of two Lolium species under Cd stress

This study was conducted to investigate the combined effects of elevated CO₂ levels and cadmium (Cd) on the root morphological traits and Cd accumulation in Lolium multiflorum Lam. and Lolium perenne L. exposed to two CO₂ levels (360 and 1 000 μl/L) and three Cd levels (0, 4, and 16 mg/L) under hydroponic conditions. The results show that elevated levels of CO₂ increased shoot biomass more, compared to root biomass, but decreased Cd concentrations in all plant tissues. Cd exposure caused toxicity to both Lolium species, as shown by the restrictions of the root morphological parameters including root length, surface area, volume, and tip numbers. These parameters were significantly higher under elevated levels of CO₂ than under ambient CO₂, especially for the number of fine roots. The increases in magnitudes of those parameters triggered by elevated levels of CO₂ under Cd stress were more than those under non-Cd stress, suggesting an ameliorated Cd stress under elevated levels of CO₂. The total Cd uptake per pot, calculated on the basis of biomass, was significantly greater under elevated levels of CO₂ than under ambient CO₂. Ameliorated Cd toxicity, decreased Cd concentration, and altered root morphological traits in both Lolium species under elevated levels of CO₂ may have implications in food safety and phytoremediation.     

High-level soluble expression of the hemA gene from Rhodobacter capsulatus and comparative study of its enzymatic properties

The Rhodobacter capsulatus hemA gene, which encodes 5-aminolevulinic acid synthase (ALAS), was expressed in Escherichia coli Rosetta (DE3) and the enzymatic properties of the purified recombinant ALAS (RC-ALAS) were studied. Compared with ALASs encoded by hemA genes from Agrobacterium radiobacter (AR-ALAS) and Rhodobacter sphaeroides (RS-ALAS), the specific activity of RC-ALAS reached 198.2 U/mg, which was about 31.2% and 69.5% higher than those of AR-ALAS (151.1 U/mg) and RS-ALAS (116.9 U/mg), respectively. The optimum pH values and temperatures of the three above mentioned enzymes were all pH 7.5 and 37 °C, respectively. Moreover, RC-ALAS was more sensitive to pH, while the other two were sensitive to temperature. The effects of metals, ethylene diamine tetraacetic acid (EDTA), and sodium dodecyl sulfate (SDS) on the three ALASs were also investigated. The results indicate that they had the same effects on the activities of the three ALASs. SDS and metal ions such as Co²⁺, Zn²⁺, and Cu²⁺ strongly inhibited the activities of the ALASs, while Mn²⁺ exerted slight inhibition, and K⁺, Ca²⁺, Ba²⁺, Mg²⁺, or EDTA had no significant effect. The specificity constant of succinyl coenzyme A [(k _cat/K _m)_S-CoA] of RC-ALAS was 1.4989, which was higher than those of AR-ALAS (0.7456) and RS-ALAS (1.1699), showing its high catalytic efficiency. The fed-batch fermentation was conducted using the recombinant strain containing the R. capsulatus hemA gene, and the yield of 5-aminolevulinic acid (ALA) achieved was 8.8 g/L (67 mmol/L) under the appropriate conditions.     

Acaricidal activities of whole cell suspension,cell-free supernatant,and crude cell extract of <Emphasis Type="Italic">Xenorhabdus stokiae</Emphasis> against mushroom mite (<Emphasis Type="Italic">Luciaphorus</Emphasis> sp.)

Xenorhabdus bacterium has been used as a biological control agent against Luciaphorus sp., a mushroom mite endemic in Thailand. To develop an effective formulation of Xenorhabdus stokiae, treatments using different parts of X. stokiae isolate PB09 culture, including whole cell suspension, cell-free supernatant, and crude cell extract, were performed. The results show that different parts of X. stokiae isolate PB09 culture could induce variable effects on mite mortality and fecundity. Application with cell-free supernatant of X. stokiae culture resulted in both the highest mite mortality rate [(89.00±3.60)%] and the lowest mite fecundity [(41.33±23.69) eggs/gravid female]. Whole cell suspension of X. stokiae isolate PB09 culture was found to be slightly less effective than its cell-free supernatant, suggesting that X. stokiae was more likely to release its metabolites with acaricidal activities to the surrounding culture media. Crude cell extract of X. stokiae was not effective against mites. Cell-free supernatant of X. stokiae isolate PB09 was the most effective biological control agent and it could be conveniently used in future formulations instead of live bacteria.     

Involvement of phosphatidate phosphatase in the biosynthesis of triacylglycerols in Chlamydomonas reinhardtii

Lipid biosynthesis is essential for eukaryotic cells, but the mechanisms of the process in microalgae remain poorly understood. Phosphatidic acid phosphohydrolase or 3-sn-phosphatidate phosphohydrolase (PAP) catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerols and inorganic orthophosphates. This reaction is integral in the synthesis of triacylglycerols. In this study, the mRNA level of the PAP isoform CrPAP2 in a species of Chlamydomonas was found to increase in nitrogen-free conditions. Silencing of the CrPAP2 gene using RNA interference resulted in the decline of lipid content by 2.4%–17.4%. By contrast, over-expression of the CrPAP2 gene resulted in an increase in lipid content by 7.5%–21.8%. These observations indicate that regulation of the CrPAP2 gene can control the lipid content of the algal cells. In vitro CrPAP2 enzyme activity assay indicated that the cloned CrPAP2 gene exhibited biological activities.     

Identification of a heat shock cognate protein 70 gene in Chinese soft-shell turtle (Pelodiscus sinensis) and its expression profiles under thermal stress

The heat shock cognate protein 70 (Hsc70) is a member of a 70-kDa heat shock protein (HSP70) family that functions as molecular chaperones. In this study, a novel Hsc70 gene from Chinese soft-shelled turtle (Pelodiscus sinensis) (tHsc70) was identified. The tHsc70 full-length complementary DNA (cDNA) is 2 272 bp long with a 1 941-bp open reading frame (ORF) encoding 646 amino acids. Three characteristic signature regions of the HSP70 family, two major domains of an adenosine triphosphate (ATP)/guanosine triphosphate (GTP) binding domain (ABD), and a substrate-binding domain (SBD) were present in the predicted tHsc70 amino acid sequence. The tHsc70 gene was expressed in Escherichia coli BL21 and the expression product reacted with the anti-Hsc70 mouse monoclonal antibody by Western blotting. Homology analysis revealed that tHsc70 shared identity from 53.9% to 87.7% at the nucleotide level, and 49.1% to 99.5% at the amino acid level with the known Hsc70s. Phylogenetic analysis showed that tHsc70 was clustered together with the Hsc70 gene of another reptile species (Alligator mississippiensis). The tHsc70 was expressed in the liver, lung, heart, and skeletal muscle. The expression patterns of tHsc70 messenger RNA (mRNA) differed among different tissues under different durations of heat stress at 40 °C. Adaptation at 25 °C for 1 h after heat stress was also different among tissues and length of heat stress. Irrespective of different profiles of expression under heat stress, tHsc70 may play roles in protecting turtles from thermal stress.     

Effect of CO2 enrichment on the glucosinolate contents under different nitrogen levels in bolting stem of Chinese kale (Brassica alboglabra L.)

The effects of CO2 enrichment on the growth and glucosinolate (GS) concentrations in the bolting stem of Chinese kale (Brassioa alboglabra L.) treated with three nitrogen (N) concentrations (5, 10, and 20 mmol/L) were investigated. Height,stem thickness, and dry weights of the total aerial parts, bolting stems, and roots, as well as the root to shoot ratio, significantly increased as CO2 concentration was elevated from 350 to 800 μl/L at each N concentration. In the edible part of the bolting stem,11 individual GSs were identified, including 7 aliphatic and 4 indolyl GSs. GS concentration was affected by the elevated CO2 concentration, N concentration, and CO2×N interaction. At 5 and 10 mmol N/L, the concentrations of aliphatic GSs and total GSs significantly increased, whereas those of indolyl GSs were not affected, by elevated atmospheric CO2. However, at 20 mmol N/L,elevated CO2 had no significant effects on the concentrations of total GSs and total indolyl GSs, but the concentrations of total aliphatic GSs significantly increased. Moreover, the bolting stem carbon (C) content increased, whereas the N and sulfur (S) contents decreased under elevated CO2 concentration in the three N treatments, resulting in changes in the C/N and N/S ratios.Also the C/N ratio is not a reliable predictor of change of GS concentration, while the changes in N and S contents and the N/S ratio at the elevated CO2 concentration may influence the GS concentration in Chinese kale bolting stems. The results demonstrate that high nitrogen supply is beneficial for the growth of Chinese kale, but not for the GS concentration in bolting stems, under elevated CO2 condition.     

Novel mutation c.980_983delATTA compound with c.986C>A mutation of the FRMD7 gene in a Chinese family with X-linked idiopathic congenital nystagmus

Objective

To screen mutations in FERM domain-containing protein 7 (FRMD7) gene in two Chinese families with X-linked idiopathic congenital nystagmus (XLICN).

Methods

Common ophthalmic data and peripheral blood of two Chinese XLICN families (families A and B) were collected after informed consent. Genomic DNA was prepared from the peripheral blood of members of the two families and from 100 normal controls. Mutations in the FRMD7 gene were determined by directly sequencing polymerase chain reaction (PCR) products.

Results

We identified a novel mutation c.980_983delATTA compound with c.986C>A mutation in the 11th exon of FRMD7 in family B, and a previously reported splicing mutation c.782G>C (p.R261G) in family A. The mutations were detected in patients and female carriers, while they were absent in other relatives or in the 100 normal controls.

Conclusions

Our results expand the spectrum of FRMD7 mutations in association with XLICN, and further confirm that the mutations of FRMD7 are the underlying molecular mechanism for XLICN.