Variation in leaf photosynthetic characteristics in wild rice species

Variations in leaf gas-exchange characteristics, leaf pigment content, and other important leaf traits were investigated in seven wild Oryza species, five hybrids, and five improved varieties. The significant variations were observed in photosynthetic pigment contents amongst different species of Oryza. The mean chlorophyll (Chl) content was higher in O. sativa (varieties and hybrids), while O. eichengeri showed the lowest Chl content. The mean carotenoid (Car) content in O. sativa (varieties and hybrids) was higher than in other wild rice species. O. eichengeri and O. barthii had significantly lower Car contents than other rice species. Significant differences were noticed in the rate of photosynthesis (P _N), stomatal conductance (g _s), transpiration rate (E), internal CO₂ concentration (C _i), specific leaf mass (SLM), and leaf thickness amongst different Oryza species. The mean P _N was the highest in O. nivara followed by O. eichengeri. The mean P _N was the lowest in O. glumaepatula, which was lower than that of cultivated varieties and hybrids of O. sativa. High rates of photosynthesis were observed in O. nivara (ACC. No. CR 100097), O. rufipogon (ACC.No. CR 100267), and O. nivara (ACC.No. CR 100008). The O. nivara and O. rufipogon genotypes with high P _N might be used in rice improvement programmes for an increase of leaf photosynthesis in rice. Multiple correlations performed between different gas-exchange characteristics and other physiological traits revealed that the rate of photosynthesis was not dependent on the leaf pigment content or the leaf thickness. A strong positive correlation between P _N and the P _N/C_i ratio, which represents the carboxylation efficiency, indicated that the observed variation in P _N was not based on pigment content or other leaf traits.     

Plasmids in Listeria

Thirty-two Listeria strains, including L. monocytogenes of the different Seeliger serovars, L. grayi and L. murrayi, have been analyzed for the presence of plasmids. A cryptic plasmid of 38.5 Md was found in seven strains: in four L. monocytogenes (serovars $\text{1}\text{2}\text{c}$, 4b, 4d, and Ivanov 1), and in both the L. grayi and the single L. murrayi strains. Restriction enzyme cleavage analysis with two restriction enzymes suggests that the plasmid is a single molecular species, pRYC16. Conjugation experiments between Streptococcus agalactiae BM6101 containing the resistance plasmid pIP501 and L. monocytogenes, L. grayi, or L. Murrayi demonstrated that pIP501 is transferred to Listeria at a mean frequency of 10^?6. pIP501 is fully expressed in Listeria and promotes its own transfer between strains of Listeria and from Listeria back to Streptococcus. It is suggested that a circulation of plasmids can take place among members of the genera Listeria and Streptococcus.     

New record of nucleopolyhedroviruses in tea looper caterpillars in India

Tea production in North-East India hit a record loss due to the widespread severe outbreak of a mixed brood of three species of looper caterpillar pests of geometrid moths (Lepidoptera) in 2008-2010. In addition to Buzura suppressaria, two newly recorded geometrids, viz., Hyposidra infixaria and Hyposidra talaca have caused widespread severe damage in recent years. In the present study we report the nucleopolyhedroviruses (NPV) isolated from the tea looper caterpillar from North-East India. We identified and characterized the NPV by cloning and sequencing a partial segment of polyhedrin gene of virus infected larvae of B. suppressaria, H. talaca and H. infixaria. A comparison of deduced amino acids of polyhedrin gene among H. talaca, H. infixaria and B. suppressaria showed that same strain was found to infect all the three loopers in India, which show high sequence identity with B. suppressaria Chinese isolates. Based on the polyhedrin sequence homology, it is predicted that a variant of B. suppressaria Chinese isolate of NPV found to infect H. talaca, H. infixaria and B. suppressaria in India.     

Variation in cuticular lipid profiles of black butterflies of the genus Papilio in Japan

Insect (epi)cuticular lipids characterize sex and species and often play an important role in mating behavior. We previously revealed that two black-colored swallowtail butterflies, Papilio polytes and Papilio protenor, show sexual dimorphism and species specificity in cuticular lipid composition and that P. polytes males use specific monoene components for mate discrimination. These findings suggest that their closely related species may have different profiles of cuticular lipids. We examined the cuticular lipid compositions of five Papilio species (P. bianor, P. maackii, P. helenus, P. macilentus, and P. memnon), closely related and sympatric to P. polytes and P. protenor, and discussed whether it is possible to discriminate between sexes, and between species based on their chemical profiles. The cuticular lipids consist mainly of C23–C31 aliphatic hydrocarbons, in which n-tricosane, n-heptacosane, and n-nonacosane are predominant. Several aliphatic ketones, aliphatic acids, and oxygenated terpenoids were also identified as major components shared by several species. There were no components exclusive to a particular species. Conspecific males and females shared most of the components but were mostly distinguishable based on their composition. Moreover, P. helenus males, P. polytes females, and P. protenor females had two different phenotypes of lipid composition. Although unrelated to the genetic lineage, the seven species were classified into four clusters based on their lipid profiles. The first cluster was composed of only P. memnon. The other six species were broadly classified into three clusters consisting of subclusters for each species: 1) P. polytes, P. helenus, P. macilentus, and several P. protenor females; 2) P. bianor and P. protenor; and 3) P. maackii and several P. helenus males. These results indicate that cuticular lipid profiles characterize the species and sex of the Papilio species and may be responsible for mate discrimination among them.     

Role of Mannose-Binding Lectin Deficiency in HIV-1 and Schistosoma Infections in a Rural Adult Population in Zimbabwe

Background

Polymorphism in the MBL2 gene lead to MBL deficiency, which has been shown to increase susceptibility to various bacterial, viral and parasitic infections. We assessed role of MBL deficiency in HIV-1 and schistosoma infections in Zimbabwean adults enrolled in the Mupfure Schistosomiasis and HIV Cohort (MUSH Cohort).

Methods

HIV-1, S. haematobium and S. mansoni infections were determined at baseline. Plasma MBL concentration was measured by ELISA and MBL2 genotypes determined by PCR. We calculated and compared the proportions of plasma MBL deficiency, MBL2 structural variant alleles B (codon 54A>G), C (codon 57A>G), and D (codon 52T>C) as well as MBL2 promoter variants -550(H/L), -221(X/Y) and +4(P/Q) between HIV-1 and schistosoma co-infection and control groups using Chi Square test.

Results

We assessed 379 adults, 80% females, median age (IQR) 30 (17–41) years. HIV-1, S. haematobium and S. mansoni prevalence were 26%, 43% and 18% respectively in the MUSH baseline survey. Median (IQR) plasma MBL concentration was 800μg/L (192-1936μg/L). Prevalence of plasma MBL deficiency was 18% with high frequency of the C (codon 57G>A) mutant allele (20%). There was no significant difference in median plasma MBL levels between HIV negative (912μg/L) and HIV positive (688μg/L), p = 0.066. However plasma MBL levels at the assay detection limit of 20μg/L were more frequent among the HIV-1 infected (p = 0.007). S. haematobium and S. mansoni infected participants had significantly higher MBL levels than uninfected. All MBL2 variants were not associated with HIV-1 infection but promoter variants LY and LL were significantly associated with S. haematobium infection.

Conclusion

Our data indicate high prevalence of MBL deficiency, no evidence of association between MBL deficiency and HIV-1 infection. However, lower plasma MBL levels were protective against both S. haematobium and S. mansoni infections and MBL2 promoter and variants LY and LL increased susceptibility to S. haematobium infection.     

Characterization of the acetyltransferase used in pheromone biosynthesis in moths: Specificity for the Z isomer in tortricidae

Characterization of the acetyltransferase (acetyl-CoA: fatty alcohol acetyltransferase) that catalyzes the conversion of fatty alcohols to acetate esters was carried out in the redbanded leafroller moth, Argyrotaenia velutinana. This enzyme is one of the last enzymes used in the pheromone biosynthetic pathway of many moths. Characterization of the acetyltransferase involved an in vitro enzyme assay using a pheromone gland homogenate. The enzyme found only in the pheromone gland, was active during the photophase and at all adult ages tested (1–5-days-old). The enzyme was derermined to be microsomal and exhibited specificity for the Z isomer of all 12, 14 and 16 carbon monounsaturated fatty alcohol substrates tested. The shape of the kinetic curves for the Z and E isomers of Δ11-tetradecenol were similar for time of incubation, protein and substrate concentration, with the Z isomer always forming 1.5–2 times more product. Substrate competition assays between Z and E11-tetradecenol indicate that one enzyme is involved and it converts the Z isomer to product faster than the E isomer. Substrate preference assays conducted with the enzyme from Choristoneura rosaceana, C. fumiferana and Platynota idaeusalis (all Tortricidae) pheromone glands also indicate specificity for the Z isomer. On the other hand, assays conducted with Trichoplusia ni (Noctuidae) and three strains (Z, E and hybrid) of Ostrinia nubilalis (Pyralidae) indicate no preferences between the Z and E isomers.     

Abundance and biomass of rotifers in relation to the environmental factors in geothermal waters in Southern Tunisia

The spatial and temporal dynamics of rotifers in relation to the physico-chemical parameters in Fish-Culture Research Station (Southern Tunisia) were studied monthly from February 2005 to January 2006. Thirteen rotifer species were found: Brachionus urceolaris, Brachionus calyciflorus, Brachionus sp., Lecane stichaea, Lecane rhytida, Lecane sp., Hexarthra mira, Rotaria tardigrada, Conochiloides natans, Trichocerca marina, Keratella quadrata, Keratella cochlearis and Notommata codonella. The most dominant rotifer was B. urceolaris (76% of total abundance). Rotifer density and water temperature were negatively correlated (r=−0.94, n=12, p=0.001). The highest abundance of rotifers was found in basin 4 (1.5×10⁵ ind m⁻³, in June 2005).     

Anthocyanins in Caprifoliaceae

The qualitative and relative quantitative anthocyanin content of 19 species belonging to the genera Sambucus, Lonicera and Viburnum in the family Caprifoliaceae has been determined. Altogether 12 anthocyanins were identified; the 3-O-glucoside (2), 3-O-galactoside (5), 3-O-(6″-O-arabinosylglucoside) (7), 3-O-(6″-O-rhamnosylglucoside) (9), 3-O-(2″-O-xylosyl-6″-O-rhamnosylglucoside) (10), 3-O-(2″-O-xylosylgalactoside) (11), 3-O-(2″-O-xylosylglucoside) (12), 3-O-(2″-O-xylosylglucoside)-5-O-glucoside (14), 3-O-(2″-O-xylosyl-6″-O-Z-p-coumaroylglucoside)-5-O-glucoside (15) and 3-O-(2″-O-xylosyl-6″-O-E-p-coumaroylglucoside)-5-O-glucoside (16) of cyanidin, in addition to the 3-O-glucosides of pelargonidin and delphinidin (1 and 3). Pigment 7 is the first complete identification of the disaccharide vicianose, 6″-O-α-arabinopyranosyl-β-glucopyranose, linked to an anthocyanidin.     

Increase in Resistance to Extended-Spectrum Cephalosporins in Salmonella Isolated from Retail Chicken Products in Japan

Extended-spectrum β-lactamase (ESBL)-producing Salmonella are one of the most important public health problems in developed countries. ESBL-producing Salmonella strains have been isolated from humans in Asian countries neighboring Japan, along with strains harboring the plasmid-mediated extended-spectrum cephalosporin (ESC)-resistance gene, ampC (pAmpC). However, only a few studies have investigated the prevalence of ESC-resistant Salmonella in chicken products in Japan, which are the main vehicle of Salmonella transmission. The aim of this study was to investigate the prevalence of ESBL-producing, pAmpC-harboring, or carbapenem-resistant Salmonella in chicken products in Japan. In total, 355 out of 779 (45.6%) chicken product samples collected from 1996–2010 contained Salmonella, resulting in 378 distinct isolates. Of these isolates, 373 were tested for resistance to ESCs, cephamycins, or carbapenems. Isolates that showed resistance to one or more of these antimicrobials were then examined by PCR and DNA sequence analysis for the presence of the bla_CMY, bla_CTX-M, bla_TEM, and bla_SHV resistance genes. Thirty-five resistant isolates were detected, including 26 isolates that contained pAmpC (bla_CMY-2), and nine ESBL-producing isolates harboring bla_CTX-M (n = 4, consisting of two bla_CTX-M-2 and two bla_CTX-M-15 genes), bla_TEM (n = 4, consisting of one bla_TEM-20 and three bla_TEM-52 genes), and bla_SHV (n = 1, bla_SHV-12). All pAmpC-harboring and ESBL-producing Salmonella isolates were obtained from samples collected after 2005, and the percentage of resistant isolates increased significantly from 0% in 2004 to 27.9% in 2010 (P for trend = 0.006). This increase was caused in part by an increase in the number of Salmonella enterica subsp. enterica serovar Infantis strains harboring an approximately 280-kb plasmid containing bla_CMY-2 in proximity to ISEcp1. The dissemination of ESC-resistant Salmonella containing plasmid-mediated bla_CMY-2 in chicken products indicates the need for the development of continuous monitoring strategies in the interests of public health.     

Involvement of Androgen Receptor in Sex Determination in an Amphibian Species

In mice and humans, the androgen receptor (AR) gene, located on the X chromosome, is not known to be involved in sex determination. In the Japanese frog Rana rugosa the AR is located on the sex chromosomes (X, Y, Z and W). Phylogenetic analysis shows that the AR on the X chromosome (X-AR) of the Korean R. rugosa is basal and segregates into two clusters: one containing W-AR of Japanese R. rugosa, the other containing Y-AR. AR expression is twice as high in ZZ (male) compared to ZW (female) embryos in which the W-AR is barely expressed. Higher AR-expression may be associated with male sex determination in this species. To examine whether the Z-AR is involved in sex determination in R. rugosa, we produced transgenic (Tg) frogs carrying an exogenous Z-AR. Analysis of ZW Tg frogs revealed development of masculinized gonads or ‘ovotestes’. Expression of CYP17 and Dmrt1, genes known to be activated during normal male gonadal development, were up-regulated in the ZW ovotestis. Testosterone, supplied to the rearing water, completed the female-to-male sex-reversal in the AR-Tg ZW frogs. Here we report that Z-AR is involved in male sex-determination in an amphibian species.     

Effects of Nematicides on Nematode Densities in Turf in Connecticut

The plant-parasitic nematodes Criconemoides lobatum, Hoplolaimus tylenchiformis, and Tylenchorhynchus dubius were present in the top 7.5 cm of sod consisting of numerous stolons and fibrous roots. Phenamiphos and 1,2-dibromo-3-chloropropane (DBCP) controlled all three species, whereas ethoprop and oxamyl controlled H. tylenchiformis and T. dubius but not C. lobatum. Benomyl and carbofuran controlled H. tylenchiformis but had poor control of C. lobatum and T. dubius. The effectiveness of carbofuran varied with the type of formulation, being most effective as a quick-release formulation. C. lobatum was the most difficult to control with chemicals. No chemical treatment improved the growth of ''Astoria colonial'' bentgrass (A. tenuis Sibth.) or Kentucky bluegrass (Poa pratensis L.) under the moist condtions prevalent in these tests.     

PanB is involved in nicotine metabolism in Pseudomonas putida

A nicotine-sensitive mutant was generated from the nicotine-degrading bacterium, Pseudomonas putida strain J5, by mini-Tn5 transposon mutagenesis. This mutant was unable to grow with nicotine as the sole carbon source but could grow with glucose. Sequence analysis showed that the Tn5 transposon inserted at the site of the ketopantoate hydroxymethyltransferase gene (panB), which had 54% identity to PanB in Escherichia coli K-12. In-frame deletion of the panB gene abolished the nicotine-degrading ability of strain J5, while complementation with panB from P. putida J5 and E. coli K-12 restored the degrading activity of the mutant to the wild-type level. These results suggest that ketopantoate hydroxymethyltransferase is a crucial enzyme in nicotine metabolism in P. putida J5.     

Stochastic processes in particle-number fluctuations in an electron-photon shower

The paper is concerned with the existence and asymptotic character of the nonlinear boundary value problemdG/dt=F(t,G,F, ¦α?β¦) (1) ¦α?β¦dF/dt=g(t,G,F, ¦α?β¦)G(o,¦α?β¦)=k ₁,G(∞,¦α?β¦)=k ₂ (2) as ¦α?β¦→ o+ The discussion is related to the problem of particle-number fluctuations in the theory of cosmic radiation andG andF denote respectively the probability generating functions for the electron distribution in an electron-initiated and a photon-initiated shower. A solution of the system (1) satisfying the boundary conditions (2) is constructed so that specified limiting conditions are fulfilled.     

Strongyloides stercoralis and Trypanosoma cruzi coinfections in a highly endemic area in Argentina

BackgroundStrongyloidiasis and Chagas disease are endemic in northern Argentina. In this study we evaluate the association between S. stercoralis and T. cruzi infections in villages with diverse prevalence levels for these parasites. Further understanding in the relationship between these Neglected Tropical Diseases of South America is relevant for the design of integrated control measures as well as exploring potential biologic interactions.MethodologyCommunity based cross-sectional studies were carried in different villages of the Chaco and Yungas regions in Argentina. Individuals were diagnosed by serology for S. stercoralis and T. cruzi. The association between S. stercoralis and T. cruzi, and between anemia and the two parasites was evaluated using two approaches: marginal (Ma) and multilevel regression (Mu).ResultsA total of 706 individuals from six villages of northern Argentina were included. A total of 37% were positive for S. stercoralis, 14% were positive for T. cruzi and 5% were positive for both. No association was found between infection with S. stercoralis and T. cruzi in any of the models, but we found a negative correlation between the prevalence of these species in the different villages (r = -0.91). Adults (> 15 years) presented association with S. stercoralis (Ma OR = 2.72; Mu OR = 2.84) and T. cruzi (Ma OR = 5.12; Mu OR = 5.48). Also, 12% and 2% of the variance of infection with S. stercoralis and T. cruzi, respectively, could be explained by differences among villages. On the other hand, anemia was associated with infection with S. stercoralis (Ma OR = 1.73; Mu OR = 1.78) and was more prevalent in adults (Ma OR = 2.59; Mu OR = 2.69).ConclusionWe found that coinfection between S. stercoralis and T. cruzi is not more frequent than chance in endemic areas. However, the high prevalence for both parasites, raises the need for an integrated strategy for the control of STH and Chagas disease.     

Mesophyll conductance variations in response to diurnal environmental factors in Myrcia paivae and Minquartia guianensis in Central Amazonia

Mesophyll conductance (g _m) is essential to determine accurate physiological parameters used to model photosynthesis in forest ecosystems. This study aimed to determine the effects of time of day on photosynthetic parameters, and to assess the effect of using either intercellular CO₂ concentration (C _i) or chloroplast CO₂ concentration (C _c), on maximum carboxylation velocity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), V _cmax. We used Amazonian saplings of Myrcia paivae and Minquartia guianensis. Photosynthetic parameters were measured using an infrared gas analyzer (IRGA); g _m was determined using both gas exchange and chlorophyll (Chl) a fluorescence and gas-exchange data alone. Leaf thickness (L _T) and specific leaf area (SLA) were also measured. Air temperature, relative humidity or understory light did not correlate with g _m and on average daily IRGA-fluorometer-determined g _m was 0.04 mol(CO₂) m^?2 s^?1 for M. paivae and 0.05 mol(CO₂) m^?2 s^?1 for M. guianensis. Stomatal conductance (g _s), g _m, electron transport rate (J _F), and light-saturated net photosynthetic rate (P _Nmax) were lower in the afternoon than in the morning. However, no effect of time of day was observed on V _cmax. L _T and SLA did not affect any of the examined parameters. IRGA-determined g _m was almost the double of the value obtained using the IRGA-fluorescence method. V _cmax values determined using C _c were about 25% higher than those obtained using C _i, which highlighted the importance of using C _c in V _cmax calculation. Decline in P _Nmax at the end of the afternoon reflected variations in g _s and g _m rather than changes in V _cmax. Diurnal variation in g _m appeared to be associated more with endogenous than with atmospheric factors.     

Gene Arrangements in Expression Vector Affect 3-Hydroxypropionic Acid Production in Klebsiella pneumoniae

Biosynthesis of 3-hydroxypropionic acid (3-HP) typically involves two sequential reactions catalyzed by glycerol dehydratase (DhaB) and aldehyde dehydrogenase (AldH). Although plasmid-dependent over-expression of the two enzymes is common, systematic investigation of gene arrangement in vector has not been reported. Here we show that gene arrangements have a noticeable influence on 3-HP production. Using Klebsiella pneumoniae as a host, three AldH-coding genes: ald4 from Saccharomyces cerevisiae, aldh from Escherichia coli, and puuC from host K. pneumoniae, were respectively ligated to dhaB. The recombinant Kp/pET-pk-ald4-dhaB (Kp refers to as K. pneumoniae, pk is a native promoter) produced the highest yield of 3-HP in comparison to both Kp/pET-pk-dhaB-ald4 and Kp/pET-pk-dhaB-pk-ald4, suggesting that the preferential expression of AldH can increase 3-HP production. Additionally, when different AldH-coding genes were respectively ligated downstream of dhaB, the recombinant Kp/pET-pk-dhaB-puuC produced more 3-HP than that by Kp/pET-pk-dhaB-aldh or Kp/pET-pk-dhaB-ald4, implying the intrinsic compatibility of native gene puuC with its host. These findings indicate the applicability of native AldH-coding gene and provide insights into strategies for metabolic engineering of multiple genes.     

A Large Insertion in bHLH Transcription Factor BrTT8 Resulting in Yellow Seed Coat in Brassica rapa

Yellow seed is a desirable quality trait of the Brassica oilseed species. Previously, several seed coat color genes have been mapped in the Brassica species, but the molecular mechanism is still unknown. In the present investigation, map-based cloning method was used to identify a seed coat color gene, located on A9 in B. rapa. Blast analysis with the Arabidopsis genome showed that there were 22 Arabidopsis genes in this region including at4g09820 to at4g10620. Functional complementation test exhibited a phenotype reversion in the Arabidopsis thaliana tt8-1 mutant and yellow-seeded plant. These results suggested that the candidate gene was a homolog of TRANSPARENT TESTA8 (TT8) locus. BrTT8 regulated the accumulation of proanthocyanidins (PAs) in the seed coat. Sequence analysis of two alleles revealed a large insertion of a new class of transposable elements, Helitron in yellow sarson. In addition, no mRNA expression of BrTT8 was detected in the yellow-seeded line. It indicated that the natural transposon might have caused the loss in function of BrTT8. BrTT8 encodes a basic/helix-loop-helix (bHLH) protein that shares a high degree of similarity with other bHLH proteins in the Brassica. Further expression analysis also revealed that BrTT8 was involved in controlling the late biosynthetic genes (LBGs) of the flavonoid pathway. Our present findings provided with further studies could assist in understanding the molecular mechanism involved in seed coat color formation in Brassica species, which is an important oil yielding quality trait.