Genetic Environments Research Articles

Co-production of SFO-1 and DHA-1 -lactamases and 16S rRNA methylase ArmA in clinical isolates of Klebsiella pneumoniae

To investigate the epidemiology and genetic characteristics of the plasmid-mediated extended-spectrum β-lactamase (ESBL) gene bla(SFO-1) in clinical isolates of ESBL-producing Klebsiella pneumoniae and Escherichia coli. The prevalence of the bla(SFO-1) gene was examined by PCR amplification. Conjugation and transformation experiments were performed and the presence of antimicrobial resistance determinants was investigated by the PCR method. The genetic environments of the bla(SFO-1) and armA genes were determined by direct sequencing of plasmid pHS20. Plasmids were typed by PCR-based replicon typing. PFGE and multilocus sequence typing were performed on SFO-producing strains. Of 158 ESBL-producing strains of K. pneumoniae, 3 (1.9%) carried the bla(SFO-1) gene. All of the SFO-producing isolates belonged to the ST11 epidemic clone, with a single PFGE type and had high-level resistance to third-generation cephalosporins, aminoglycosides and ciprofloxacin. The bla(SFO-1) gene was co-transferred with the armA, aac(6')-Ib-cr and bla(TEM-1) genes by transformation, whereas the armA, bla(DHA-1) and qnrB4 genes were co-transferred by conjugation. The armA genes were located within the composite transposon Tn1548 on two different plasmids in the strain 08-129. The bla(SFO-1) gene was located upstream of an ampR gene from the coding region and flanked by two inverted repeats of IS26. Plasmids carrying bla(DHA-1) were identified as IncFII, while the bla(SFO-1)-bearing plasmids were non-typeable. Although SFO-1 is a low-occurrence ESBL, it has been captured by a plasmid accumulating multiple resistance determinants including armA and aac(6')-Ib-cr, and accompanied by a large DHA-1-bearing IncFII plasmid in a prevalent K. pneumoniae ST11 clone.

Increased drought tolerance and wider adaptability of qDTY 12.1 conferred by its interaction with qDTY 2.3 and qDTY 3.2

The genetic basis of high grain yield under reproductive-stage drought was studied using an F3-derived population generated from the cross of upland rice (Oryza sativa L.) cultivars Vandana and Way Rarem. Contributed by the susceptible parent Way Rarem, locus qDTY 12.1 was hypothesized to have interaction with loci from the Vandana genome to enhance the grain yield of tolerant line Vandana under drought. A test of the digenic interaction of qDTY 12.1 showed that two loci, qDTY 2.3 on chromosome 2 and qDTY 3.2 on chromosome 3, significantly increased the yield and harvest index of qDTY 12.1 -positive lines under severe upland and lowland drought conditions. qDTY 2.3 and qDTY 3.2 , in interaction with qDTY 12.1 , reduced days to flowering and plant height of qDTY 12.1 -positive lines under stress and non-stress conditions in upland. BC2F3-derived backcross inbred lines (BILs) were used to validate these results and identify new quantitative trait loci. Lines with qDTY 2.3 and qDTY 12.1 showed increased yield over Way Rarem under severe and moderate stress conditions, in upland. IR84996-50-4-B-4, a selection from one of the BILs, yielded more than the popular drought-tolerant cultivars Apo, UPLRi7, and IR74371-54-1-1 under severe stress conditions. Introgressed segments from Vandana also improved yield under non-stress conditions. The results indicate that digenic interactions can explain the genetic control of complex quantitative traits such as grain yield under drought, and a few interacting loci with large effects on grain yield or yield-related traits may enhance drought response across a wide range of genetic backgrounds and environments when introgressed together.

Perspectives from the Common Ground

Perspectives from the Common Ground

Molecular characterization of IMP-type metallo- -lactamases among multidrug-resistant Achromobacter xylosoxidans

To analyse the metallo-β-lactamase (MBL) genes and their genetic environments in clinical isolates of Achromobacter xylosoxidans. From January 2004 to December 2010, four MBL-producing, multidrug-resistant (MDR) A. xylosoxidans strains were isolated and analysed at a tertiary care university hospital in Japan. Species-level identification was confirmed by 16S ribosomal RNA gene sequencing. Molecular typing was performed using PFGE, the presence of MBL genes was detected using PCR, and integron gene cassettes were examined by cloning and sequence analysis of integron PCR products. The plasmids obtained from individual isolates were analysed based on EcoRI restriction patterns, Southern hybridizations using digoxigenin-labelled probes for bla(IMP-1) and bla(IMP-19) as well as conjugation and transformation experiments. No clonal relationship was found among the four A. xylosoxidans isolates. Three isolates harboured bla(IMP-1) and one isolate harboured bla(IMP-19). These MBL genes were carried on class 1 integrons. Four different class 1 integron gene cassette arrays were found, including orf1-bla(IMP-1)-aacA4, bla(IMP-1)-bla(IMP-1)-nit1/nit2-catB3-bla(IMP-1)-bla(IMP-1), aacA4-bla(IMP-1) and bla(IMP-19). The restriction pattern of the plasmid DNA obtained from each isolate was unique and the hybridization analyses revealed the presence of each MBL gene within a plasmid. Moreover, all of the plasmids carrying an MBL gene could be transformed into Escherichia coli HST08. This study provides genetic evidence for the existence of IMP-type MBL genes in MDR A. xylosoxidans isolates. Moreover, the present findings provide evidence that A. xylosoxidans can receive IMP-type MBL genes via plasmid-mediated transfer, which contributes to their carbapenem resistance.

Replicon sequence typing of IncF plasmids and the genetic environments of blaCTX-M-15 indicate multiple acquisitions of blaCTX-M-15 in Escherichia coli and Klebsiella pneumoniae isolates from South Korea

The purpose of this study was to investigate variations in IncF plasmids and the genetic environments of bla(CTX-M-15) in CTX-M-15-producing Escherichia coli and Klebsiella pneumoniae isolates from South Korea. A total of 56 E. coli and 15 K. pneumoniae isolates, which were previously characterized for CTX-M-15 production, sequence type by multilocus sequence typing and replicon type, were included in this study. Replicon sequence typing for IncF plasmids was performed and the genetic environments of bla(CTX-M-15) were determined using PCR and sequencing. A total of 34 and 10 IncF-replicon sequence types (RSTs) were identified among the E. coli and K. pneumoniae isolates, respectively. Only eight and four IncF-RSTs were found in multiple isolates of E. coli and K. pneumoniae, respectively. No common IncF-RSTs were found between E. coli and K. pneumoniae isolates. Five and three different bla(CTX-M-15) genetic environments were identified in E. coli and K. pneumoniae isolates, respectively. Even in the same E. coli clone, diverse IncF-RSTs and bla(CTX-M-15) genetic environments were identified. Diverse IncF plasmids have incorporated into diverse strains of E. coli and K. pneumoniae, contributing to the spread of the CTX-M-15 extended-spectrum β-lactamase in South Korea. It can also be inferred that bla(CTX-M-15) has not been transferred directly from E. coli to K. pneumoniae.

Characterization of Enterobacteriaceae producing OXA-48-like carbapenemases in the UK

To characterize UK clinical isolates of Enterobacteriaceae producing OXA-48-like carbapenemases and to compare their resistance plasmids. Twenty-six enterobacteria producing OXA-48-like enzymes were studied. These were from 22 diverse hospitals in the UK. Isolates of Escherichia coli and Klebsiella pneumoniae were assigned to clonal lineages by multilocus sequence typing. Carbapenemase genes and their genetic environments were characterized by PCR and sequencing. Resistance plasmids were transferred by transformation or conjugation and compared by restriction analysis and PCR for genes encoding critical plasmid functions. Thirteen isolates of K. pneumoniae, 10 E. coli and 2 Enterobacter cloacae harboured a classical bla(OXA-48) gene; the K. pneumoniae isolates belonged to 11 sequence types (STs) and the E. coli to 7 STs, including ST131 and ST38. The bla(OXA-48) genes were located within either Tn1999 or Tn1999.2 transposons on related ≈ 50 kb or ≈ 62 kb plasmids, which lacked other resistance genes or, in one isolate, on an ≈ 140 kb plasmid that also encoded OXA-9 and CTX-M group-9 β-lactamases. One India-linked K. pneumoniae isolate had a bla(OXA-181) gene in association with an ISEcp1 insertion sequence on a 7 kb plasmid. Horizontal transfer of related plasmids has facilitated the spread of OXA-48 carbapenemase into multiple strains of several Enterobacteriaceae species. The clonal diversity of the producers suggests repeated introduction into the UK. Low carbapenem MICs for some producers complicates detection and creates a risk for unrecognized spread.

Role of Common bla OXA-24/OXA-40 -Carrying Platforms and Plasmids in the Spread of OXA-24/OXA-40 among Acinetobacter Species Clinical Isolates

The spread of OXA-24/OXA-40 (OXA-24/40)-producing Acinetobacter spp. in the Iberian Peninsula has been strongly influenced by clonal expansion, but the role of horizontal gene transfer has scarcely been explored. bla(OXA-24/40)-carrying plasmids and genetic environments were characterized in representative (n = 15) Acinetobacter species clinical isolates (obtained between 2001 and 2007) by Acinetobacter baumannii PCR-based replicon typing, sequencing, hybridization, and restriction fragment length polymorphism. Besides the identification of bla(OXA-24/40) within the chromosomes of some isolates, the circulation of common bla(OXA-24/40)-carrying plasmids (30-kb repA_AB; 10-kb aci2) and genetic backbones among Acinetobacter spp. was demonstrated.

Genes, Environments, Personality, and Successful Aging: Toward a Comprehensive Developmental Model in Later Life

Outcomes in aging and health research, such as longevity, can be conceptualized as reflecting both genetic and environmental (nongenetic) effects. Parsing genetic and environmental influences can be challenging, particularly when taking a life span perspective, but an understanding of how genetic variants and environments relate to successful aging is critical to public health and intervention efforts. We review the literature, and survey promising methods, to understand this interplay. We also propose the investigation of personality as a nexus connecting genetics, environments, and health outcomes. Personality traits may reflect psychological mechanisms by which underlying etiologic (genetic and environmental) effects predispose individuals to broad propensities to engage in (un)healthy patterns of behavior across the life span. In terms of methodology, traditional behavior genetic approaches have been used profitably to understand how genetic factors and environments relate to health and personality in somewhat separate literatures; we discuss how other behavior genetic approaches can help connect these literatures and provide new insights. Co-twin control designs can be employed to help determine causality via a closer approximation of the idealized counterfactual design. Gene-by-environment interaction (G × E) designs can be employed to understand how individual difference characteristics, such as personality, might moderate genetic and environmental influences on successful aging outcomes. Application of such methods can clarify the interplay of genes, environments, personality, and successful aging.

Faba bean adaptation to autumn sowing under European climates

Faba bean (Vicia faba L.) is an important grain legume widely grown as a spring crop to avoid frost damage. However, there is interest in winter types for the expected benefits in grain yield as compared to spring ones. In the current experiments, we compared field performance in autumn sowings of 15 faba bean winter-type cultivars that were sown in two consecutive autumns in 12 climatically contrasting sites in Austria, France, Germany, Spain, and the UK. GGE biplot analyses (genotype plus genotype-by-environment interaction) were conducted to evaluate yield performance of faba bean genotypes and identification of mega-environments. Crossover genotype × environment was large and mainly due to the geoclimatic area. GGE biplot allowed identification of three mega-environments, namely continental, oceanic, and Mediterranean. Due to the climatic diversity of the environments, no cultivar performed well in all environments. Cultivars Clipper, Castel, Target, Wizard, and Gabl-107 performed well in oceanic mega-environment, whereas cultivars Castel, HIX, and Target performed well in continental mega-environment. None of the studied cultivars were suited to Mediterranean environments, and only Irena was able to give some modest yield at Cordoba. The average tester coordinate (defined by the average of first and second principal components of all environments) allowed to evaluate cultivars for their yielding ability and stability and to evaluate environments for their discriminating ability and to be more representative of the mega-environment. Thus, Wizard and Gabl-107 were the highest yielding cultivars being relatively stable over oceanic and continental environments. In contrast, the cultivars Irena and Divine yielded poorly at all environments. The results support the specific breeding for each major geoclimatic zone based on distinct genetic bases and selection environments.

Variable composition of heme oxygenases with different regiospecificities in Pseudomonas species

Heme oxygenases (HO) degrade heme yielding iron, carbon monoxide and one of four possible biliverdin (BV) isomers. Pseudomonas aeruginosa PAO1 is thus far the only organism to contain two HOs with different regiospecificities: BphO and PigA. While BphO cleaves heme to exclusively yield BV IXα, PigA produces the BV isomers IXβ and IXδ. We bioinformatically identified putative HOs in diverse Pseudomonas strains, tested their enzymatic functionality and determined their regiospecificity. Surprisingly, even high amino acid sequence identities to the P. aeruginosa HOs were not sufficient to correctly predict the HO regiospecificity in all cases. Based on our results, Pseudomonas strains differ in their HO composition containing either BphO or PigA or both HO types. Concomitantly with the existence of bphO is the occurrence of at least one gene encoding a bacterial phytochrome implying that only BV IXα is the sufficient phytochrome chromophore. In contrast, pigA genes are organized in gene clusters associated with iron utilization implying a role of PigA in iron acquisition. However, at least in strains containing no PigA this function maybe fulfilled by BphO. Only a combination of homology searches and analyses of genetic environments is appropriate for a reliable prediction of the regiospecificity of Pseudomonas HOs.

Qnr, aac(6′)-Ib-cr and qepA genes in Escherichia coli and Klebsiella spp.: genetic environments and plasmid and chromosomal location

To characterize the location and genetic environments of qnr, aac(6')-Ib-cr and qepA genes related to quinolone resistance in 19 Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca strains. Genetic environments of the indicated genes were studied by cloning, PCR mapping and sequencing. The location of these genes was analysed by S1-PFGE and PFGE-I-CeuI and hybridization with specific probes. Associated antibiotic resistance mechanisms and molecular typing of strains were also investigated. The studied strains carried the aac(6')-Ib-cr, qepA, qnrS1, qnrB6, qnrB4 and oqxAB genes, with aac(6')-Ib-cr being the most prevalent. E. coli strains belonged to sequence types (STs) ST648, ST131, ST224 and ST205, and K. pneumoniae strains to ST433, ST341, ST152, ST15 and ST431. Different genetic environments of quinolone resistance genes were observed, and some of them had not been previously detected and registered in GenBank. The aac(6')-Ib-cr gene was mainly located in class 1 integrons or associated with the Tn1721 transposon in E. coli and associated with the aac(3)-II gene in Klebsiella. All these structures contained mechanisms of gene acquisition and/or dissemination, such as IS26. The studied quinolone resistance genes were mostly detected in IncF and IncN plasmids in E. coli and in IncR plasmids in Klebsiella, but in some strains the chromosomal location of the aac(6')-Ib-cr gene was detected for the first time. The bla(CTX-M-15), bla(OXA-1), tet(A), aac(3)-II and aph(3')-Ia genes and class 1 integrons were found in most strains. The aac(6')-Ib-cr gene was detected for the first time in the chromosome, although a plasmidic location was the most frequently found, with differentiation of plasmids types in E. coli versus Klebsiella.

Application of Marker Assisted Backcrossing to Introgress the Submergence Tolerance QTL <i>SUB</i>1 into the Vietnam Elite Rice Variety-AS996

The result of the study contributes to enhancing and sustaining future livelihoods and food security in Vietnam vis-a-vis climate change. An innovative strategy based on marker-assisted backcrossing (MABC) was used to transform popular rice variety AS996 into the one can tolerate submergence while maintaining its original characteristics preferred by farmers and consumers. The submergence tolerance QTL SUB1 counts for up to 70% of the submergence tolerant and provides a marked improvement of submergence tolerance in all genetic backgrounds and environments tested so far. Parental diversity was carried out with 460 markers. Of which, 53 polymorphic markers were used for assessment on BC1F1, BC2F1 and BC3F1 generations. The best BC1F1 plant was P422 with highest recipient allele was 87.5%, while the additional chosen plants were P412, P428, P215 and P39 (81% - 84%). All these plants were used to develop BC2F1 generation. The six BC2F1 plants were used to develop BC3F1 and BC2F2 were the plants number P422-11 and P422-14 having 93.75% recipient alleles and P422-12, P422-3, P39-17, P39-25 having 92.25% recipient alleles. Total of 445 BC3F1 plants were confirmed the introgresion of SUB1 using ART5 and SC3. After three generations of backcrossing, application of MABC resulted in the best BC3F1 individual P422-14-177 with 100% of recipient alleles based on the number of 53 markers used with only the introgression size of SUB1 was 0.3Mb between ART5 and SC3. Phenotyping was carried out on BC3F1 and BC2F2 of the selected lines. The survival ratio of these selected lines and IR64SUB1 were the same. It convinced the successfully introgress SUB1 into AS996 rice variety. The breeding line BC4F1 having 100% genetic background of donor variety is ready for develop new submergence tolerant rice variety ASS996-SUB1 to cope with climate change.

Characterization of plasmids encoding extended-spectrum -lactamases and their addiction systems circulating among Escherichia coli clinical isolates in the UK

To characterize plasmids encoding extended-spectrum β-lactamases (ESBLs) from a recent UK collection of clinical Escherichia coli isolates. The isolates comprised 118 ESBL producers referred from 54 laboratories. Plasmids were transferred by electroporation, and their incompatibility groups, associated addiction systems and resistance genes with the flanking genetic environments were identified by PCR or sequencing. Seventy isolates had plasmids encoding CTX-M-15 (n = 53), CTX-M-14 (n =9), CTX-M-27 (n = 1), CTX-M-3 (n = 2) and SHV-12 (n = 5) ESBLs that were transformable; non-transformable ESBLs were mainly CTX-M enzymes (42/48). Most transformable bla(CTX-M-15) genes (43/53) were harboured on single replicon or multireplicon IncF plasmids, with IncFIA4-FIB1-FII31 (n = 11) and IncFIA1-FII2 (n = 15) being most frequent; the latter included eight pEK499 plasmids, typical of UK epidemic strain A. Plasmids harbouring bla(CTX-M-14) belonged variously to IncF, IncI1 and IncHI2 types, and 16 encoding CTX-M or SHV enzymes were non-typeable. Only IncF plasmid types carried the addiction systems sought and those with bla(CTX-M-15) frequently harboured bla(OXA-1) and aac(6')-Ib-cr, and often transferred trimethoprim and tetracycline resistance; those with bla(CTX-M-14) encoded trimethoprim, sulphonamide, streptomycin and tetracycline resistance. Most ESBL genes were associated with the well-known mobile elements ISEcp1 and IS26, but nearly half (23/55) of the ISEcp1 sequences upstream of bla(CTX-M-15) were interrupted by an IS26 at various positions. Most ESBLs (70/118) were encoded by transformable plasmids, although a sizable minority could not be transformed. The majority of transformable plasmids (51/70; 72.9%) were diverse multiresistant IncF types possessing multiple addiction systems. The spread of bla(CTX-M-15) can be attributed not just to clonal expansion, but also to the horizontal dissemination of related plasmids.

Evolution of an Incompatibility Group IncA/C Plasmid Harboring bla CMY-16 and qnrA6 Genes and Its Transfer through Three Clones of Providencia stuartii during a Two-Year Outbreak in a Tunisian Burn Unit

During a 2-year period in 2005 and 2006, 64 multidrug-resistant Providencia stuartii isolates, including 58 strains from 58 patients and 6 strains obtained from the same tracheal aspirator, were collected in a burn unit of a Tunisian hospital. They divided into four antibiotypes (ATB1 to ATB4) and three SmaI pulsotypes (PsA to PsC), including 49 strains belonging to clone PsA (48 of ATB1 and 1 of ATB4), 11 strains to clone PsB (7 of ATB2 and 4 of ATB3), and 4 strains to clone PsC (ATB3). All strains, except for the PsA/ATB4 isolate, were highly resistant to broad-spectrum cephalosporins due to the production of the plasmid-mediated CMY-16 β-lactamase. In addition, the 15 strains of ATB2 and ATB3 exhibited decreased quinolone susceptibility associated with QnrA6. Most strains (ATB1 and ATB3) were gentamicin resistant, related to an AAC(6')-Ib' enzyme. All these genes were located on a conjugative plasmid belonging to the incompatibility group IncA/C(2) of 195, 175, or 100 kb. Despite differences in size and in number of resistance determinants, they derived from the same plasmid, as demonstrated by similar profiles in plasmid restriction analysis and strictly homologous sequences of repAIncA/C(2), unusual antibiotic resistance genes (e.g., aphA-6), and their genetic environments. Further investigation suggested that deletions, acquisition of the ISCR1 insertion sequence, and integron cassette mobility accounted for these variations. Thus, this outbreak was due to both the spread of three clonal strains and the dissemination of a single IncA/C(2) plasmid which underwent a remarkable evolution during the epidemic period.

QTL Detection for Rice Grain Shape Using Chromosome Single Segment Substitution Lines

Rice grain shape is one of the important factors affecting grain quality and yield, but it is liable to be influenced by genetic backgrounds and environments. The chromosome single segment substitution lines (SSSLs) in rice have been considered as ideal populations to identify the quantitative trait loci (QTLs). In this study, 22 QTLs affecting rice grain shape were detected to be distributed on eight chromosomes except chromosomes 6, 9, 11 and 12 by using SSSLs. Among them, seven QTLs conditioned grain length, six conditioned grain width, five affected grain length-width ratio and four controlled grain thickness.

Energy Requirement for Maintenance and Egg Production for Broiler Breeder Hens

3 Abstract: Mathematical modeling is an accounting tool that can be used for predicting the nutritional requirements for poultry with different genetic strains, environments and stages of meat gain or eg g production. Models are also useful for describing or predicting the animal's production process. Modeling the daily ME requirement of broiler breeder hens requires partitioning Metabolizable Energy (ME) requirements into maintenance, egg mass and body weight gain. Determining the daily energy requirement for maintenance and egg production in breeders requires separating the daily energy needs for egg production from energy needs of maintenance. The objective of the research reported herein was: 1.) to obtain information about body tissue changes and egg composition for breeders being fed specific intakes of ME in a set environment and 2.) to evaluate a technique for partitioning the Metabolizable Energy (ME) requirement into maintenance and production for each individual breeder. An estrogen antagonist, TAMOXIFEN ((Z)-1-1(p-Dimethylaminoethoxyphenyl)-1,2-diphenyhl-1butene) (TAM), was used to separate the ME needs into two periods: laying and non-laying. Broiler breeder hens were provided TAM to stop egg production and their individual ME requirement for maintenance determined. Each broiler breeder resumed egg production when TAM was withdrawn and the ME requirement for egg production and BW gai n determined. The estimated ME required for maintenance for breeders (MEm) housed in a constant 21C was 98.3 kcal/kgBW , MEg for gain was 5.6 kcal/g and MEe for egg mass was 2.4 kcal/g. The energy efficiencies 0.75 for protein gain (kp), fat gain (kf) and egg calories (ke) were 34%, 79% and 65.7%, respectively. The use of TAM provided an opportunity to estimate breeder maintenance requirements and reduce the interdependence in estimating factorial coefficients while partitioning production energy.

Prevalence and characterisation of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates in healthy volunteers in Tunisia

The objective of this investigation was to analyse the carriage rate of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli in faecal samples of healthy humans in Tunisia and to characterise the recovered isolates. One hundred and fifty samples were inoculated on MacConkey agar plates supplemented with cefotaxime (2 μg/ml) for ESBL-positive E. coli recovery. The characterisation of ESBL genes and their genetic environments, detection of associated resistance genes, multilocus sequence typing (MLST) and phylogroup typing were performed by polymerase chain reaction (PCR) and sequencing. The presence and characterisation of integrons and virulence factors were studied by PCR and sequencing. ESBL-positive E. coli isolates were detected in 11 of 150 faecal samples (7.3%) and one isolate/sample was further characterised. These isolates contained the blaCTX-M-1 (ten isolates) and blaTEM-52c genes (one isolate). The ISEcp1 (truncated by IS10 in four strains) and orf477 sequences were found upstream and downstream, respectively, of all bla (CTX-M-1) genes. Seven different sequence types (STs) and three phylogroups were identified among CTX-M-1-producing isolates [ST/phylogroup (number of isolates)]: ST58/B1 (3), ST57/D (2), ST165/A (1), ST155/B1 (1), ST10/A (1), ST398/A (1) and ST48/B1 (1). The TEM-52-producing isolate was typed as ST219 and phylogroup B2. Six ESBL isolates contained class 1 integrons with the gene cassettes dfrA17-aadA5 (five isolates) and dfrA1-aadA1 (one). Healthy humans in the studied country could be a reservoir of CTX-M-1-producing E. coli.

Maize Transgenes Containing Zein Promoters are Regulated by opaque2

ABSTRACTUnderstanding epistatic interactions between transgenes and native genes is critical for predicting the response of transgenes to different genetic backgrounds and environments. Our objective was to determine if predicted epistatic interactions occur between maize (Zea mays L.) transgenes carrying zein promoters and opaque2, a transcriptional regulator of zein genes. Expression of the transgenes was significantly decreased in kernels containing the opaque2 mutation. Native zein proteins in these kernels were reduced as well. Thus, transgene expression mirrored expression of the native gene that contributed the promoter of the transgene. This work demonstrates that information about native gene expression may be useful for predicting transgene expression, reducing the risk of unintended consequences of transgene expression.

Fine mapping of a major quantitative trait locus, qFLL6.2, controlling flag leaf length and yield traits in rice (Oryza sativa L.)

Fine mapping of a quantitative trait locus, qFLL6.2, controlling flag leaf length (FLL) and yield traits in rice was conducted using four sets of near isogenic lines (NILs) that were developed from a common residual heterozygote at F7 generation of the indica rice cross Zhenshan 97/Milyang 46. Each of the NIL sets consisted of 40 lines that are S1 progenies of ten maternal homozygotes, ten paternal homozygotes, and 20 heterozygotes differing in a portion of the 1.19-Mb interval RM3414–RM6917 on the short arm of rice chromosome 6. Analysis of phenotypic differences among the three genotypic groups in each NIL set delimited qFLL6.2 to a 62.1-kb region flanked by simple sequence repeat marker RM3414 and sequence-tagged site marker Si2944. This QTL explained 52.73% of the phenotypic variance, and the Zhenshan 97 allele increased FLL by 2.40 cm. Based on data collected from homozygous lines of three of the NIL sets, qFLL6.2 was shown to have major effects on all the three yield traits analyzed, including the number of spikelets per panicle, the number of filled grains per panicle, and grain weight per panicle. A comparison of the different groups revealed that the effect of qFLL6.2 was highly consistent across different genetic backgrounds and environments, providing a good candidate for map-based cloning and investigating the source–sink relationship in rice.

덕평리 지역 우라늄광상의 흑색점판암과 탄질점판암의 지구화학적 특성

Geochemical study was performed on black slates and interbedded U-bearing coaly slates in Deokpyeongri area, the representative uranium mineralized district of the Ogcheon Metamorphic Belt, to discuss the genetic environments of the uranium deposit. REE concentration (254 ppm) of the black slates is higher than that (169 ppm) of the coaly slates and NASC-normalized REE patterns of the coaly slates show remarkable positive Eu anomaly. l11e redox-sensitive trace elements such as V, Cr, Co, Ni, Mo and U in the coaly slates are highly enriched compared to the black slates, especially for V of 24 times, Mo of 62 times, and U of 60 times. In additions, Pd and Pt are also enriched in the coaly slates. Positive Eu anomaly and the noticeable enrichment of the elements listed above compared to those of NASC indicate that those elements were not derived from common seawater but deposited under high temperature and reducing environment of submarine hydrothermal activities. Wide compositional ranges of major elements (: 3.98~11.88, : 25.6~139.06, : 6.80~46.85) also suggest that the source rocks of the sediments are mixtures of sedimentary rocks and igneous rocks. Higher sulfur contents in the coaly slates, 2.6 wt.%, than those in the black slates, 0.6 wt.% also indicates that the former was influenced by hydrothermal activities containing much sulfur. These geochemical characteristics are similar to the genetic environments of South China type PGE deposits (Mo-Ni-Zn-PGE) which is geotectonically correlated with the Ogcheon Metamorphic Belt and is known as sedimentary-exhalative deposits. In conclusions, the uranium and other metallic elements mineralization seems to have occurred in the sedimentary basin that was affected by submarine hydrothermal activities and rich in organic materials under oxygen-poor environments as well.