A pair of two-component regulatory genes ecrA1/A2 in S. coelicolor

INTRODUCTION S.coelicolor as a model system has been ex-tensively studied with the aid of genetic and mo-lecular techniques. Its ability to produce four anti-biotics (Hopwood et al., 1995), namely actinorhodin (Act), undecylprodigiosin (Red), Calcium-Depend- ent Antibiotic (CDA) and methylenomycin (Mmy), enables studies of pathyway-specific and pleiotropic regulation of antibiotic production. In which, Red is a red-pigmented antibiotic and Act is coelicolor- pigmented antibiotic tha…     

A pair of two-component regulatory genes ecrA1/A2 in S.coelicolor

Two-component genes are kinds of genetic elements involved in regulation of antibiotic production in Streptomyces coelicolor. DNA microarray analysis revealed that ecrA1/A2, which mapped at distant sites from red locus and encode respectively the kinase and regulator, expressed coordinately with genes of Red specific biosynthetic pathway, ecrA1 and ecrA2 gene-disruptive mutants were constructed using homogenotisation by reciprocal double crossover. Fermentation data showed that the undecylprodigiosin (Red) level of production was lower than that of wild-type strain. However, the change of the actinorhodin (Act) production level was not significant compared with wild type. Thus, these experiment results confirmed that the two-component system ecrA 1/A2 was positive regulatory element for red gene cluster.     

Review：BRCA1/2 associated hereditary breast cancer

Breast cancer is one of the leading causes of death in women today. Some of the patients are hereditary, with a large proportion characterized by mutation in BRCA1 and/or BRCA2 genes. In this review, we provide an overview of these two genes, focusing on their relationship with hereditary breast cancers. BRCA1/2 associated hereditary breast cancers have unique features that differ from the general breast cancers, including alterations in cellular molecules, pathological bases, biological behavior, and a different prevention strategy. But the outcome of BRCA1/2 associated hereditary breast cancers still remains controversial; further studies are needed to elucidate the nature of BRCA1/2 associated hereditary breast cancers. Project supported by the National Natural Science Foundation of China (No. 30772510) and the Joint Program of Ministry of Health and Zhejiang Provincal Government of China (No. WKJ2006-2-008)     

Mixed G<Emphasis Type="Italic">l</Emphasis><Subscript>2</Subscript>/G<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> multi-channel multi-objective control synthesis for discrete time systems

This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl ₂ (Gl ₂) and generalizedH ₂ (GH ₂) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl ₂/GH ₂ control problem can be solved less conservatively using computationally tractable algorithms developed in the paper. Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176)     

Controversial opinion: evaluation of <Emphasis Type="Italic">EGR1</Emphasis> and <Emphasis Type="Italic">LAMA2</Emphasis> loci for high myopia in Chinese populations

Functional studies have suggested the important role of early growth response 1 (EGR1) and Laminin α2-chain (LAMA2) in human eye development. Genetic studies have reported a significant association of the single nucleotide polymorphism (SNP) in the LAMA2 gene with myopia. This study aimed to evaluate the association of the tagging SNPs (tSNPs) in the EGR1 and LAMA2 genes with high myopia in two independent Han Chinese populations. Four tSNPs (rs11743810 in the EGR1 gene; rs2571575, rs9321170, and rs1889891 in the LAMA2 gene) were selected, according to the HapMap database (http://hapmap.ncbi.nlm.nih.gov), and were genotyped using the ligase detection reaction (LDR) approach for 167 Han Chinese nuclear families with extremely highly myopic offspring (<?10.0 diopters) and an independent group with 485 extremely highly myopic cases (<?10.0 diopters) and 499 controls. Direct sequencing was used to confirm the LDR results in twenty randomly selected subjects. Family-based association analysis was performed using the family-based association test (FBAT) software package (Version 1.5.5). Population-based association analysis was performed using the Chi-square test. The association analysis power was estimated using online software (http://design.cs.ucla.edu). The FBAT demonstrated that all four tSNPs tested did not show association with high myopia (P>0.05). Haplotype analysis of tSNPs in the LAMA2 genes also did not show a significant association (P>0.05). Meanwhile, population-based association analysis also showed no significant association results with high myopia (P>0.05). On the basis of our family- and population-based analyses for the Han Chinese population, we did not find positive association signals of the four SNPs in the LAMA2 and EGR1 genes with high myopia.     

Comparative studies on phenotypic plasticity of two herbs,<Emphasis Type="Italic">Changium smyrnioides</Emphasis> and<Emphasis Type="Italic">Anthriscus sylvestris</Emphasis>

The endangered medicinal herb,Changium smyrnioides can only be found in deciduous forest gaps within the middle to northern subtropical broad-leaved evergreen forest zone of China. The considerable plasticity of its shoot and root structure helps it to capture light more effectively in winter and early spring, and to adapt to the soil moisture conditions in its narrow habitat. Another medicinal plant,Anthriscus sylvestris, is of similar economic importance but commonly distributed widely. In contrast toC. smyrnioides, it has low structural plasticity. It is also specialized to adapt to the moist and sunny environment, where habitat, such as the banks of creeks and rivers, is abundant. Project supported by the National Basic Research Program (973) of China (No. G2000046805) and the National Natural Science Foundation of China (No. 39970058)     

Seymour Benzer and T4 <Emphasis Type="Italic">r</Emphasis>II

One of the goals of genetics is to understand genes in as much detail as possible. For instance, with respect to a given gene, one would like to know its chromosomal location, its physical and genetic size, its neighbours, the number of mutations/alleles defining the gene, the order of mutations, the genetic/physical distance between them, etc. Thus, rather than focusing on the whole genome, one focuses on the finer details of a given genetic segment. The exercise of probing such details is called ‘fine structure genetic analysis’. There are several pioneers who have contributed enormously to this area in many bacterial and phage systems. Two stalwarts, Seymour Benzer and Charles Yanofsky, stand preeminent among them. In the following pages I present briefly Benzer’s outstanding work on the fine structure of the rII region of bacteriopage T4. These path-breaking studies contributed significantly to our understanding of the structure, organization and function of genes. R Jayaraman is an Emeritus Professor of Molecular Biology at the School of Biological Sciences, Madurai Kamaraj University, Madurai, where he taught and carried out research in the area of microbial genetics for three decades.     

Science Letters： A TOM1 homologue is required for multiplication of Tobacco mosaic virus in Nicotiana benthamiana

The AtTOM1 gene ofArabidopsis thaliana had been shown to be essential for the efficient multiplication of Tobacco mosaic virus （TMV） in A. thaliana. In this study, we cloned an AtTOM1-like gene from Nicotiana benthamiana named as NbTOM1. Sequence alignment showed that NbTOM1 is closely related to AtTOM1 homologues of N. tabacum and Lycopersicon esculentum with 97.2% and 92.6% nucleotide sequence identities, respectively. Silencing of NbTOM1 by a modified viral satellite DNA-based vector resulted in complete inhibition of the multiplication of TMV in N. benthamiana. The result suggests that inhibition of NbTOM1 via RNA silencing is a potentially useful method for generating TMV-resistant plants.     

Study on<Emphasis Type="Italic">Bombyx mori</Emphasis> silk treated by oxygen plasma

Study of the morphology, aggregation structure and properties ofBombyx mori silk treated by low temperature oxygen plasma showed that slight flutes appeared on the surface ofBombyx mori silk fiber and that its surface structure changed after plasma treatment. The conformation also changed and crystalline degree decreased. The stannic filling rate of treated fiber was improved. Because of etching, the weight of the fiber decreased but the breaking strength changed little after short-time treatment. Project (No. 50073013) supported by the National Natural Science Foundation of China     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of herbicide resistance in creeping bentgrass and colonial bentgrass

Embryogenic calli were induced from the seeds of creeping bentgrass (Agrostis palustris Huds.) cv. Regent and colonial bentgrass (Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4–7 days and then co-cultivated withAgrobacterium tumefaciens, LBA4404. which contains plasmid vector-pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co-cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4-D, 12–15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2–3 months of selection, the actively growing calli of ‘Regent’ and ‘Tiger’ were transferred to MS medium with 12–15 mg/L PPT and 250 mg/L cefotazime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.     

Distribution of<Emphasis Type="Italic">H. pylori</Emphasis> antigens in gastric mucosa and its significance

Objective: To investigate the distribution ofH. pylori antigens in the gastric mucosa in patients withH. pylori infection, and the relationship between the distribution and gastric cancer. Methods: Of 112 patients confirmed by pathological study to have chronic superficial gastritis, precancerous changes (chronic atrophic gastritis, intestinal metaplasia or atypical hyperplasia) and gastric cancer, 28 wereH. pylori negative and 84 wereH. pylori positive.H. pylori antigens in the gastric mucosa were detected by immunohistochemistry. Results: TheH. pylori positive group, comprised 12 of 22 (50.0%) in the chronic superficial gastritis group, 22 of 25 (88.0%) in the precancerous changes group and 13 of 35 (37.1%) in the gastric cancer group. The positive rates ofH. pylori antigens in the cytoplasm progressively increased, respectively at 0.0% (0/12), 63.6% (14/22) and 84.6% (11/13) for the same groups (χ ²=19.76,P=0.000);H. pylori antigens were located in the mucus layer and above the neck of the mucosal gland in 9 of 12 (75.0%) cases with chronic superficial gastritis, at the neck of the mucosal gland and the isthmus in 12 of 22 (54.5%) cases with precancerous changes, below the isthmus in 9 of 13 (69.2%) cases with gastric cancer (χ ²=25.30,P=0.000). In theH. pylori negative group, noH. pylori antigen was observed. Conclusion: With the progression of chronic superficial gastritis→precancerous changes→gastric cancer,H. pylori antigens progressively migrated from the outer part to the inner part of the cell, and from the superficial to the deep gastric mucosa.     

Improving the antioxidant activity and enriching salvianolic acids by the fermentation of <Emphasis Type="Italic">Salvia miltiorrhizae</Emphasis> with <Emphasis Type="Italic">Geomyces luteus</Emphasis>

The antioxidant activities and total phenolic content of fermented Salvia miltiorrhiza with fungus Geomyces luteus were investigated. The results revealed that G. luteus fermentation could significantly improve the antioxidant activity and total phenolic content of S. miltiorrhiza. The main antioxidant constituents were characterized by spectroscopic analysis as salvianolic acids. High-performance liquid chromatography (HPLC) quantification also showed the enhanced content of salvianolic acid B after fermentation. The present study suggests that G. luteus fermentations are effective in the S. miltiorrhiza salvianolic acids’ enrichment process.     

Learned suppression of photopositive tendencies in<Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

A task was designed to teach individual flies to avoid a lighted area after they had displayed an initial preference for it. The flies walked in a T-maze and chose between a lighted and a darkened alley leading, respectively, to a lighted and a darkened vial. Flies that were photopositive on a first trial were subjected to an aversive stimulus (a filter paper inserted into the lighted vial and wetted with a quinine solution), and they performed 16 training trials; they learned to avoid the lighted vial. The flies trained with water instead of quinine in the lighted vial still displayed avoidance of the lighted vial, but to a lesser extent. The flies trained with a dry filter paper in the lighted vial did not show any increase in avoidance during training. Like the flies trained with no quinine at all, those trained to avoid the lighted vial under a partial reinforcement condition (one half of the trials with quinine, the other half with a dry vial) did not master the task. Finally, removal of the quinine after an avoidance acquisition criterion was reached resulted in an extinction process.     

Effect of temperature on batch elastase production by <Emphasis Type="Italic">Bacillus</Emphasis> sp. EL31410

The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 °C to 28 °C, were evaluated in shake flask. The result indicated that 37 °C was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 °C. This result was verified by batch fermentation in 5-L bioreactor under 37 °C and 30 °C temperature, respectively. The specific cell growth rate at 37 °C was higher than that at 30 °C during earlier stage of cultivation. The maximum value [5.5 U/(h·g DCW)] of elastase formation rate occurred at 24 h at 30 °C compared to 4.6 U/(h·g DCW) at 30 h at 37 °C. Based on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 °C or 30 °C, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 °C, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 °C in batch process. It was concluded that cultivation at constant temperature of 30 °C was appropriate for elastase production by Bacillus sp. EL31410. Project (No. 20276064) supported by the National Natural Science Foundation of China     

Mutagenic effects of chromium trioxide on root tip cells of <Emphasis Type="Italic">Vicia faba</Emphasis>

In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO₃) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, micronucleus rate and chromosome aberration rate of Vicia faba root tip cells. The results showed that the effects of CrO₃ concentration on the mitotic indexes were complicated. CrO₃ increases the micronucleus rate of Vicia faba root tip cells. It was found that within certain range of CrO₃ concentration the micronucleus rate increased systematically with increased concentration of CrO₃, but that the micronucleus rate decreased at higher level of CrO₃ and that CrO₃ also caused various types of chromosome aberration at a rate which increased systematically with increased concentration of CrO₃. We concluded that CrO₃ has significant mutagenic effect on Vicia faba root tip cells. Project supported by Wenzhou Technology Bureau (No. S2002A015) and Wenzhou “551” Talented People Fund of China     

Targeting of human aFGF gene into silkworm,<Emphasis Type="Italic">Bombyx mori</Emphasis> L. through homologous recombination

The long-arm and short-arm genes of fibroin light chain (L-chain) of silkworm,Bombyx Mori L., and the gene of human acidic fibroblast growth factor were cloned respectively and subsequently inserted into a transfer vector pVL 1392 used as a tool to target the L-chain region of the silkworm genome. Genomic DNA from their offsprings was extracted and the expected targeting was detected using polymerase chain reaction and DNA sequencing, as well as protein analysis. The results showed that positive events occurred and that the FGF gene was integrated into the L-chain locus through homologous recombination. Project supported by the Scientific Research Foundation for Returned Overseas Chinese Scholars, Education Ministry of China and the Natural Science Foundation of Zhejiang Province (No. 301306), China     

Meta-analysis of <Emphasis Type="Italic">C242T</Emphasis> polymorphism in <Emphasis Type="Italic">CYBA</Emphasis> genes: risk of acute coronary syndrome is lower in Asians but not in Caucasians

Background

A lot of studies have demonstrated that C242T polymorphism in CYBA genes may play an important role in the pathological process of acute coronary syndrome (ACS). However, the results are not consistent. To further evaluate this debate, we performed a meta-analysis to determine the relationship between C242T polymorphism and ACS.

Methods and results

We screened PubMed/MEDLINE, EBSCIO, and EMBASE research reports until Mar. 2014 and extracted data from 10 studies involving 6102 ACS patients and 8669 controls. Subgroup analysis by ethnicity documented a significant decreased risk of ACS for C242T polymorphism in the Asian population under allelic comparison (odd ratio (OR) 0.73; 95% confidence intervals (CI) 0.64–0.83), dominant model (OR 0.71; 95% CI 0.62–0.82), and homozygote comparison (OR 0.57; 95% CI 0.35–0.92). However, in the overall population and especially with Caucasians, no significant association was uncovered. Further meta-regression analysis revealed that the heterogeneity among studies was largely attributed to ethnicity. No publication bias was detected through a funnel plot and an Egger’s linear regression test.

Conclusions

Taken together, our results suggest that the C242T polymorphism might be a protective factor against developing ACS in the Asian population. Further researches will be needed to identify the confounding factors which modified the protective effect of T allele among Caucasians.