Detection and Partial Characterization of Milk vetch dwarf virus Isolates from Faba Bean (Vicia faba L.) in Yunnan Province, China

A virus disease of faba bean ( Vicia faba L.) in China, characterized by leaf yellowing and rolling and plant stunting, was shown to be caused by a virus of the genus Nanovirus based on serological reactions to nanovirus-specific monoclonal antibodies and the generation of polymerase chain reaction amplicons using nanovirus-specific primers. To identify the faba bean-infecting nanovirus, regions of the DNA components encoding the master replication initiator protein and capsid protein of two nanovirus isolates from China were cloned, sequenced and compared with those of other members of the genus Nanovirus . The two Chinese virus isolates shared nucleotide sequence identities ranging from 95 to 98% with the type isolate of Milk vetch dwarf virus (MDV) from Japan. They were thus identified as isolates of MDV, a virus so far known to cause important diseases of legumes in Japan. This is the first record of MDV-infecting faba bean in China.     

MGMT Ile143Val polymorphism,dietary factors and the risk of breast,colorectal and prostate cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study

O⁶-Methylguanine-DNA methyltransferase (MGMT) repairs DNA damage caused by alkylating agents including N-nitroso compounds from diet. MGMT Ile143Val polymorphism may lead to less DNA damage repair and increased cancer risk depending on the environmental exposures. We investigated interactions between dietary factors and the MGMT Ile143Val polymorphism in relation to breast, colorectal and prostate cancer risk. There were 276/1498, 273/2984 and 312/1486 cases/controls for the breast, colorectal and prostate cancer studies respectively; all nested within the EPIC-Norfolk study, a prospective cohort of approximately 25,000 men and women aged 40–79. Baseline 7-day food diary data were collected for dietary assessment. MGMT Ile143Val polymorphism was not overall associated with breast, colorectal and prostate cancer risk. There was a significant interaction between this polymorphism and intake of red and processed meat on colorectal cancer risk (P_interaction = 0.04) suggesting an increased risk among carriers of the variant genotype compared to the MGMT Ile143Ile common genotype. A lower colorectal cancer risk was seen with higher intake of vitamin E and carotene among the variant genotype group but not in the common genotype group (P_interaction = 0.009 and P_interaction = 0.005 for vitamin E and carotene, respectively). A higher prostate cancer risk was seen with higher alcohol intake among the variant genotype (OR = 2.08, 95% CI = 1.21–3.57, P_interaction = 0.0009) compared to the common genotype with lower alcohol intake. In this UK population, the MGMT Ile143Val polymorphism was not overall associated with breast, colorectal and prostate cancer risk. There was evidence for this polymorphism playing a role in modulating the risk of prostate cancer in presence of alcohol. For colorectal cancer, the MGMT Ile143Val polymorphism may confer increased or decreased risk depending on the dietary exposure.     

Role of polymer–protein interaction on partitioning pattern of bovine pancreatic trypsinogen and alpha-chymotrypsinogen in polyethyleneglycol/sodium tartrate aqueous two-phase systems

The partitioning pattern of bovine trypsinogen (TRPz) and alpha-chymotrypsinogen (ChTRPz) was investigated in a low impact aqueous two-phase system formed by polyethyleneglycol (PEG) and sodium tartrate (NaTart) pH 5.00. ChTRPz exhibited higher partition coefficients than TRPz did in all the assayed systems. The decrease in PEG molecular weight and the increase in tie line length were observed to displace the partitioning equilibrium of both proteins to the top phase, while phase volume ratios in the range 0.5–1.5 showed not to affect protein partitioning behaviour. Systems formed by PEG of molecular weight 600 with composition corresponding to a high tie line length (PEG 12.93%, w/w and NaTart 21.20%, w/w) are able to recover most of both zymogens in the polymer-enriched phase. A crucial role of PEG–protein interaction in the partitioning mechanism was evidenced by isothermal calorimetric titrations. The major content of highly exposed tryptophan rests, present in ChTRPz molecule, could be considered to be determinant of its higher partition coefficient due to a selective charge transfer interaction with PEG molecule. A satisfactory correlation between partition coefficient and protein surface hydrophobicity was observed in systems formed with PEGs of molecular weight above 4000, this finding being relevant in the design of an extraction process employing aqueous two-phase systems.     

Intracellular Accumulation of High Levels of γ-Aminobutyrate by Listeria monocytogenes 10403S in Response to Low pH: Uncoupling of γ-Aminobutyrate Synthesis from Efflux in a Chemically Defined Medium

It is well established that the glutamate decarboxylase (GAD) system is central to the survival of Listeria monocytogenes at low pH, both in acidic foods and within the mammalian stomach. The accepted model proposes that under acidic conditions extracellular glutamate is transported into the cell in exchange for an intracellular γ-aminobutyrate (GABA_i). The glutamate is then decarboxylated to GABA_i, a reaction that consumes a proton, thereby helping to prevent acidification of the cytoplasm. In this study, we show that glutamate supplementation had no influence on either growth rate at pH 5.0 or survival at pH 2.5 when L. monocytogenes 10403S was grown in a chemically defined medium (DM). In response to acidification, cells grown in DM failed to efflux GABA, even when glutamate was added to the medium. In contrast, in brain heart infusion (BHI), the same strain produced significant extracellular GABA (GABA_e) in response to acidification. In addition, high levels of GABA_i (>80 mM) were found in the cytoplasm in response to low pH in both growth media. Medium-swap and medium-mixing experiments revealed that the GABA efflux apparatus was nonfunctional in DM, even when glutamate was present. It was also found that the GadT2D2 antiporter/decarboxylase system was transcribed poorly in DM-grown cultures while overexpression of gadD1T1 and gadD3 occurred in response to pH 3.5. Interestingly, BHI-grown cells did not respond with upregulation of any of the GAD system genes when challenged at pH 3.5. The accumulation of GABA_i in cells grown in DM in the absence of extracellular glutamate indicates that intracellular glutamate is the source of the GABA_i. These results demonstrate that GABA production can be uncoupled from GABA efflux, a finding that alters the way we should view the operation of bacterial GAD systems.The capacity to produce γ-aminobutyric acid (GABA) through glutamate decarboxylation is commonly found in both Gram-negative and Gram-positive bacterial genera (10, 12). In several cases, this reaction has been shown to be critical for bacteria to survive potentially lethal acidic environments (15, 18, 20). It is generally held that the hydrogen ion consumed during the decarboxylation reaction helps to prevent excessive acidification of the cytoplasm, thereby protecting the cells against acidic environments. The GABA produced in the reaction is removed from the cell through the activity of an antiporter that exchanges a GABA molecule for an extracellular glutamate (Glu) molecule (6, 12).In Listeria monocytogenes, the Gram-positive food-borne pathogen that was the focus of the present study, the glutamate decarboxylase (GAD) system has been shown to play an essential role in acid tolerance (8, 9). Mutants compromised in their ability to catalyze this decarboxylation reaction survive poorly both in acidic foods (8) and gastric juice (9). The GAD system in most L. monocytogenes strains is encoded by a total of five genes. There are three genes, designated gadD1, gadD2, and gadD3, that encode distinct glutamate decarboxylase enzymes and two genes, designated gadT1 and gadT2, that encode two Glu-GABA antiporters. These genes are organized at three separate genetic loci: gadD1T1, gadT2D2, and gadD3 (11). The decarboxylase/antiporter system encoded by gadT2D2 plays a central role in allowing survival under extreme acidic conditions; mutants lacking either the GadT2 antiporter or the GadD2 decarboxylase are highly sensitive to low pH (9, 11). In contrast, the GadD1/GadT1 decarboxylase/antiporter system appears to be more important for growth under moderately acidic conditions (11). The genes encoding this system are absent from most serotype 4 strains, and this generally correlates with a reduced ability of these strains to grow well at low pH (11). The role of GadD3 is less clear since it has not been possible to generate a deletion mutant lacking the corresponding gene (9).Although the activity of the decarboxylase is generally thought to be coupled directly to the antiporter activity (i.e., the efflux of GABA is coupled to the supply of Glu) there is little direct evidence for this, even in bacteria where the system has been very well characterized. Most studies of the bacterial GAD system have used complex growth media when studying acid tolerance and GABA production (7, 8, 15). In the present study, we sought to determine whether extracellular Glu is a requirement for the production of GABA in L. monocytogenes. To do this, we have used a chemically defined growth medium (DM) that supports the growth of L. monocytogenes but does not include Glu. The results indicate that cells cultured in this medium do not produce extracellular GABA (GABA_e) in response to low pH but are capable of accumulating substantial pools of intracellular GABA (GABA_i). We establish that some component of complex medium is indispensable for efficient efflux of GABA. Surprisingly, supplementation of the DM with Glu failed to stimulate the extracellular release of GABA. We show that the GadD2/GadT2 decarboxylase/antiporter system is not transcribed when cells are grown in DM and suggest that this accounts for much of the difference in GABA production between cells cultured in DM and complex growth medium.     

Synthesis and cytotoxic activities of chloropyridylimineplatinum(II) and chloropyridyliminecopper(II) surface-functionalized poly(amidoamine) dendrimers

The preparations of novel platinum and copper metallodendrimers are reported. Surface modified first generation (G0) poly(amidoamine) (PAMAM) dendritic Schiff base, prepared via a condensation reaction was coordinated with platinum chloride and copper chloride yielding [G0-Py₄-[PtCl₂]₄] (4D) and [G0-Py₄-[CuCl₂]₇] (7E) respectively. These functionalized hyper-branched complexes were characterized by IR spectroscopy and CHN analysis. 4D was further characterized through ¹H and ¹³C spectroscopy, while 7E was characterized using matrix-assisted laser desorption ionization time-of-flight (MALDI/TOF) Mass Spectrometer. The cytotoxic effects of the compounds against cells of neoplastic origin (MOLT-4, MCF-7) and cells of benign origin (Chang Liver) were studied. Their cytotoxicities were then compared to their mono-nuclear analogues, [(MeCONHCH₂CH₂NCHPy)(PtCl₂)] (1D) and [(MeCONHCH₂CH₂NCHPy)(CuCl₂)] (1E). The multi-nuclear complexes showed increased cytotoxic activities as compared to their respective mono-nuclear compounds. Most notably, significant inhibitions were observed for 7E on all cell lines, in which its IC₅₀ values were 11.1 ± 0.6, 10.2 ± 1.5 and 8.7 ± 0.7 μM against MOLT-4, MCF-7 and Chang Liver cells respectively. The multi-nuclear copper-based complexes (7E) are therefore most effective against a cancer cell line (MOLT-4) and a cisplatin-resistant cell line (MCF-7).     

Parents' Knowledge about Enterobiasis Might Be One of the Most Important Risk Factors for Enterobiasis in Children

To know the prevalence of Enterobius vermicularis infection and what are the most important risk factors, we evaluated the incidence and risk factors of enterobiasis among children attended in kindergartens in Busan metropolitan city, Republic of Korea. A total of 1,674 children from 21 kindergartens in 11 of 16 autonomous districts of Busan were evaluated for E. vermicularis infection by the cellotape anal swab technique. The overall egg-positive rate for E. vermicularis was 10.7% (179/1,674), and the prevalence of enterobiasis in each kindergarten ranged between 0% and 32.4%. There was an increasing tendency of the egg positive rate according to the population density; the higher the population density communities had, the higher egg-positive rate for E. vermicularis was detected (P = 0.001). Among personal hygiene factors involving children, thumb-sucking (P = 0.036) and fingernail-trimming (P = 0.024) were highly associated with enterobiasis. In addition, taking anthelmintic medications against E. vermicularis infection was strongly associated with enterobiasis (P = 0.014). Moreover, parents'' knowledge of enterobiasis was correlated significantly with the incidence of enterobiasis of their children (P = 0.006). In conclusion, we need to consider not only personal hygiene but also parents'' knowledge about enterobiasis as a factor in order to develop new strategies for elimination or to complete reduction of enterobiasis in Korea.     

Translation elongation factor eEF1A2 is essential for post-weaning survival in mice

Translation elongation factor eEF1A, formerly known as EF-1 alpha, exists as two variant forms; eEF1A1, which is almost ubiquitously expressed, and eEF1A2, whose expression is restricted to muscle and brain at the level of whole tissues. Expression analysis of these genes has been complicated by a general lack of availability of antibodies that specifically recognize each variant form. Wasted mice (wst/wst) have a 15.8-kilobase deletion that abolishes activity of eEF1A2, but before this study it was unknown whether the deletion also affected neighboring genes. We have generated a panel of anti-peptide antibodies and used them to show that eEF1A2 is expressed at high levels in specific cell types in tissues previously thought not to express this variant, such as pancreatic islet cells and enteroendocrine cells in colon crypts. Expression of eEF1A1 and eEF1A2 is shown to be generally mutually exclusive, and we relate the expression pattern of eEF1A2 to the phenotype seen in wasted mice. We then carried out a series of transgenic experiments to establish whether the expression of other genes is affected by the deletion in wasted mice. We show that aspects of the phenotype such as motor neuron degeneration relate precisely to the relative expression of eEF1A1 and eEF1A2, whereas the immune system abnormalities are likely to result from a stress response. We conclude that loss of eEF1A2 function is solely responsible for the abnormalities seen in these mice.     

海南鹦哥岭自然保护区的珍稀濒危植物与保育

对鹦哥岭的珍稀濒危植物进行野外调查表明,本区共有野生分布的珍稀濒危植物79种,隶属于47科71属。其中属于1999年国家重点一级保护4种,如海南苏铁(Cycas hainansis)、坡垒(Hopea hainansis)、台湾苏铁(Cy-cas taiwaniana)和伯乐树(Bretschneidera sinensis),国家二级保护14种。建议将18种列入国家保护名录中,20种列入省级保护名录,其中有30种为海南特有种。鹦哥岭珍稀濒危植物面临的威胁主要有原始森林面积的减少、人为毁林开荒和分布区限制。针对珍稀濒危植物的现状和受到的威胁,提出了应重点加强保护的6个地点及相应的保护对策和建议。