27,977 research outputs found

    Mamey (Mammea americana L.) in Martinique Island : un patrimonio para ser valorizados

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    Introduction. Mamey (Mammea americana L., Clusiaceae) was present in Martini-que before the Spanish colonization. Its distribution area includes tropical America and the Carib-bean. A significant phenotypical diversity is observed on the island, with fruits of very uneven quality as well as various agronomic, pomological and biochemical characteristics. The aim of our work was to localize, identify and characterize trees considered of superior quality. Materials and methods. A survey carried out between April and September 2005 allowed the selection of 10 trees renowned by the people as bearing high-quality fruits. These fruits present a small number of seeds and nonadhesive pulp, and develop a sweet taste as well as a strong flavor. During the year 2006, pomological description and biochemical analysis (total soluble solids and total titrable acidity) were carried out on the fruits. Results and discussion. The biometric and biochemical characteristics measured were generally better than those cited in the literature. Some accessions stand out and present great assets for their promotion for the fresh market as well as for processing. Moreover, some tendencies emerged from the variability observed for a few characters: thus, the variability of the biochemical characteristics measured within one accession, as well as between accessions originating from the same land, is low. It is null for the seed adhesion to the pulp for fruits belonging to the same accession. Conclusion and perspectives. Our work is one of the first relating to identification and characterization of phenotypical diversity of the M. americana L. species, especially in Martinique Island. Our results are likely to pro-mote the development of a diversification network. Some highlighted trends suggest new research to be able to distinguish the role of the environmental versus genetic components in the performance of the phenotypes observed

    Polyamine, peroxidase activity and total protein content during storage of bird-of-paradise

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    The present study was aimed to the determination of the effect of storage on some biochemical characteristics (PAs content, POX activity and total protein content) of flower tissue of bird-of-paradise. Flowers were selected and labeled, avoiding any mechanical damage, and randomly distributed in recipients for two postharvest trials. In the first experiment, flowers were placed in recipients containing tap water and stored in a cold room, at 7.5 \ubaC and 90 % RH, for a period of 12 days. In experiment 2, flowers were stored in room temperature for a period of 6 days. For biochemical characteristics, samples (sepals, petals, stems and bracts) from experiment 1 were collected at 0, 4, 8 and 12 days, and at 0, 2, 4 and 6 days for experiment 2. Results showed that flower bracts, stored at 7.5 \ub0C, presented a lower content of PAs (Put and Spd), when compared to samples stored at room temperature. In both experiments, a high content of PAs (Spm) was observed in flower tissues in relation to Put and Spd. An increase of POX activity was observed in sepals stored in the cold, and was related to PAs degradation during senescence. No differences in total protein content were observed between the two treatments. The present study provides numeric results on changes in level of PAs, POX activity and total protein during postharvest of bird-of-paradise

    Population gene introgression and high genome plasticity for the zoonotic pathogen Streptococcus agalactiae

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    The influence that bacterial adaptation (or niche partitioning) within species has on gene spillover and transmission among bacteria populations occupying different niches is not well understood. Streptococcus agalactiae is an important bacterial pathogen that has a taxonomically diverse host range making it an excellent model system to study these processes. Here we analyze a global set of 901 genome sequences from nine diverse host species to advance our understanding of these processes. Bayesian clustering analysis delineated twelve major populations that closely aligned with niches. Comparative genomics revealed extensive gene gain/loss among populations and a large pan-genome of 9,527 genes, which remained open and was strongly partitioned among niches. As a result, the biochemical characteristics of eleven populations were highly distinctive (significantly enriched). Positive selection was detected and biochemical characteristics of the dispensable genes under selection were enriched in ten populations. Despite the strong gene partitioning, phylogenomics detected gene spillover. In particular, tetracycline resistance (which likely evolved in the human-associated population) from humans to bovine, canines, seals, and fish, demonstrating how a gene selected in one host can ultimately be transmitted into another, and biased transmission from humans to bovines was confirmed with a Bayesian migration analysis. Our findings show high bacterial genome plasticity acting in balance with selection pressure from distinct functional requirements of niches that is associated with an extensive and highly partitioned dispensable genome, likely facilitating continued and expansive adaptation

    Two highly divergent alcohol dehydrogenases of melon exhibit fruit ripening-specific expression and distinct biochemical characteristics

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    Alcohol dehydrogenases (ADH) participate in the biosynthetic pathway of aroma volatiles in fruit by interconverting aldehydes to alcohols and providing substrates for the formation of esters. Two highly divergent ADH genes (15% identity at the amino acid level) of Cantaloupe Charentais melon (Cucumis melo var. Cantalupensis) have been isolated. Cm-ADH1 belongs to the medium-chain zinc-binding type of ADHs and is highly similar to all ADH genes expressed in fruit isolated so far. Cm-ADH2 belongs to the short-chain type of ADHs. The two encoded proteins are enzymatically active upon expression in yeast. Cm-ADH1 has strong preference for NAPDH as a co-factor, whereas Cm-ADH2 preferentially uses NADH. Both Cm-ADH proteins are much more active as reductases with Kms 10–20 times lower for the conversion of aldehydes to alcohols than for the dehydrogenation of alcohols to aldehydes. They both show strong preference for aliphatic aldehydes but Cm-ADH1 is capable of reducing branched aldehydes such as 3-methylbutyraldehyde, whereas Cm-ADH2 cannot. Both Cm-ADH genes are expressed specifically in fruit and up-regulated during ripening. Gene expression as well as total ADH activity are strongly inhibited in antisense ACC oxidase melons and in melon fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. These data suggest that each of the Cm-ADH protein plays a specific role in the regulation of aroma biosynthesis in melon fruit

    L-asparaginase production review: bioprocess design and biochemical characteristics

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    In the past decades, production of biopharmaceuticals has gained high interest due to its high sensitivity, specificity and lower risk of negative effects to patients. Biopharmaceuticals are mostly therapeutic recombinant proteins produced through biotechnological processes. In this context, L-Asparaginase (L-Asparagine amidohydrolase, L-ASNase (E.C. 3.5.1.1)) is a therapeutic enzyme that has been abundantly studied by researchers due to its antineoplastic properties. As a biopharmaceutical, L-ASNase has been used in the treatment of acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML) and other lymphoid malignancies, in combination with other drugs. Besides its application as a biopharmaceutical, this enzyme is widely used in food processing industries as an acrylamide mitigation agent and as a biosensor for the detection of L-Asparagine in physiological fluids at nano-levels. The great demand for L-ASNase is supplied by recombinant enzymes from Escherichia coli and Erwinia chrysanthemi. However, production processes are associated to low yields and proteins associated to immunogenicity problems, which leads to the search for a better enzyme source. Considering the L-ASNase pharmacological and food importance, this review provides an overview of the current biotechnological developments in L-ASNase production and biochemical characterization aiming to improve the knowledge about its production.publishe

    Changes in training load, running performance, lower body power and biochemical characteristics of back players throughout a professional Rugby Union season

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    The aim of this study was to observe and quantify changes in training load (TL), running performance, lower body power and biochemical characteristics of professional rugby union back players over an entire season. Eight professional players (age: 25.8 ± 4.6 y) participated in this study. Session-RPE (S-RPE) and microtechnologies (GPS) were used for assessing training load (TL). During the season, running performance was monitored using the YoYo Recovery Test Level-2 (YYRT2) and lower body power performance using the drop jump (DJ) test. Changes in hematological, endocrine and muscle damage parameters were examined through 3 blood samples taken at separate times throughout the season. TL progressively and significantly (p < 0.001) decreased throughout the season particularly due to the decrease in the training volume. The last blood sample of the season revealed a significant (p < 0.001) increase in hematological parameters and a significant increase (p < 0.01) in cortisol blood concentration without change in the testosterone/cortisol ratio. No significant change in YYRT2 performance was observed over the season, while DJ test performance was significantly lower during the first 2 blocks of the season compared to other blocks. The training volume showed a significant negative correlation with DJ-test performances (TD: r = -0.49 and S-RPE: r = -0.40, p < 0.001). Although there was a decrease in training volume throughout the season, there was no significant changes in running performance. Furthermore, lower body power production showed a significant increase in particular during the last part of the season

    Characterization of Francisella species isolated from the cooling water of an air conditioning system.

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    Strains of Francisella spp. were isolated from cooling water from an air conditioning system in Guangzhou, China. These strains are Gram negative, coccobacilli, non-motile, oxidase negative, catalase negative, esterase and lipid esterase positive. In addition, these bacteria grow on cysteine-supplemented media at 20 °C to 40 °C with an optimal growth temperature of 30 °C. Analysis of 16S rRNA gene sequences revealed that these strains belong to the genus Francisella. Biochemical tests and phylogenetic and BLAST analyses of 16S rRNA, rpoB and sdhA genes indicated that one strain was very similar to Francisella philomiragia and that the other strains were identical or highly similar to the Francisella guangzhouensis sp. nov. strain 08HL01032 we previously described. Biochemical and molecular characteristics of these strains demonstrated that multiple Francisella species exist in air conditioning systems

    Biochemical characteristics and antibiogram patterns of some gram-negative nonfermentors

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    This study was undertaken, chiefly, for the purpose of characterizing biochemically a random sample of non fermentative bacilli obtained from local hospitals and determining the prevalence of Ps. aeruginosa among them. A second objective was to compare the antibiogram patterns obtained in this study with those reported by other investigators, and thirdly to establish a baseline for future comparative studies

    Clinical and biochemical characteristics of children with juvenile idiopathic arthritis

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    Objective: To determine the clinical and biochemical characteristics of children with Juvenile Idiopathic Arthritis (JIA) at a tertiary care centre in Karachi, Pakistan. Study Design: A descriptive study. Place and Duration of Study: Paediatric Rheumatology Clinic of The Aga Khan University Hospital (AKUH), Karachi, from January 2008 to December 2011. Methodology: Clinical and laboratory profile and outcome of children less than 15 years of age attending the Paediatric Rheumatology Clinic of the Aga Khan University, Karachi with the diagnosis of Juvenile Idiopathic Arthritis according to International League against Rheumatism were studied. These children were classified into different types of JIA; their clinical and laboratory characteristics, response to therapy and outcome was evaluated. Results: Sixty eight patients satisfying the criteria of International League against Rheumatism (ILAR) for Juvenile Idiopathic Arthritis were enrolled during the study period of four consecutive years, their age ranged from 9 months to 15 years. Mean age at onset was 6.45 ± 4.03 years while mean age at diagnosis was 7.60 ± 3.93 years. Polyarticular was the most predominant subtype with 37 (54%) patients, out of these, 9 (24%) were rheumatoid factor positive. An almost equal gender predisposition was observed. Fever and arthritis were the most common presenting symptoms, with only 2 patients presenting with uveitis. Conclusion: The clinico-biochemical characteristics of JIA at the study centre showed a pattern distinct with early onset of disease, high frequency of polyarticular type and a higher rheumatoid factor (QRA) and ANA positivity in girls
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