Rangeland utilization for livestock production in central Argentina has apparently resulted in the replacement of preferred mid-grasses (Poa ligularis and Stipa clarazii) by preferred short-grasses ...(Piptochaetium napostaense and Stipa tenuis) and avoided grasses (Stipa tenuissima and Stipa eriostachya). However, the botanical composition in the pristine condition is unknown due to the lack of historical data and relict areas. The objective of this study was to analyze soil phytolith assemblages from a representative site of central Argentina rangelands to test the presumed floristic changes. Soil phytolith assemblages (SPAs) were compared with three plant phytolith assemblages (PPAs), each of it made up of two species. One PPA was integrated by the preferred mid-grasses P. ligularis and S. clarazii, another by the preferred short-grasses P. napostaense and S. tenuis, and a third one by the avoided grasses S. eriostachya and S. tenuissima. For each PPA, the proportion of species representing the best fit with SPAs was estimated by considering all possible lineal combinations between the phytolith assemblage of the two integrating species, and selecting that representing the minimum distance to SPA. The highest degree of similarity between SPAs and PPAs corresponded to the PPA integrated by P. ligularis and S. clarazii. Our results support the hypothesis of the dominance of preferred mid-grasses in the pristine condition in rangelands of central Argentina, and that a shift towards the dominance of preferred short-grasses and avoided grasses has occurred in its present disturbed condition.
Background and Aims Phytolith reference collections are a prerequisite for accurate interpretation of soil phytolith assemblages aimed at reconstructing past vegetation. In this study a phytolith ...reference collection has been developed for several grasses native to central Argentina: Poa ligularis, Piptochaetium napostaense, Stipa clarazii, Stipa tenuis, Stipa tenuissima, Stipa eriostachya, Stipa ambigua, Stipa brachychaeta, Pappophorum subbulbosum, Digitaria californica. Bothriochloa edwardsiana and Aristida subulata. Methods For each species, phytoliths present in the leaf blades were classified into 47 morphotypes, and their relative frequency determined by observing 300-400 phytoliths per sample (n = 5). Data were analyzed by complete linkage cluster analysis, using the Morisita Index as measure of association. Key Results The results showed differentiation among phytolith assemblages at species level or at plant functional type level. Cluster analysis separated C3 from C4 species and palatable from non-palatable species. Conclusions This study highlights the possibility of reconstructing past vegetation in central Argentina grasslands through the analysis of soil phytolith assemblages.
Nassella neesiana (Chilean needle grass) is a South American grass species that is a serious weed in Australia and New Zealand. The rust fungus Uromyces pencanus is a promising biocontrol agent that ...could be used to control the weed in both countries. Extensive host range testing has been conducted to explore the specificity of the rust. In this paper we discuss the different degrees of invasion by the rust of the tissues of target and non-target species; the plant defences elicited by such invasion at the cellular level; and their relevance to the biological control of Chilean needle grass.
The leaf architecture of Tipuana Benth., Cascaronia Griseb. and Bergeronia Micheli, is described and compared, evaluating the importance of these foliar characters in their taxonomy. Each genus ...presents characters that allow their differentiation: in Tipuana tipu (Benth.) Kuntze, the basal pairs of secondary veins have an eucamptodromous model, with simple intersecondary veins which move through the intercostal area towards the margin; the last marginal venation is looped. In Cascaronia astragalina Griseb., secondary veins have capillary thickness and the last marginal venation is incomplete. In Bergeronia sericea Micheli, there are abaxial prominent secondary veins, and tertiary veins emerging in rigth angles; the last marginal venation is fimbrated. The venation characters observed are similar to those previously cited for different genera of Dalbergieae and some cited in other tribes of Papilionoideae. However, they cannot define, for themselves, the taxonomic position of the three genera and must be considered together with other morphological and reproductive structures.
In vitro selection tests such as exposure to low pH and bile salts, competitive exclusion of pathogens, adherence to cell lines and prokaryotic-eukaryotic co-cultures have been commonly used to ...predict the functional properties of lactobacilli and bifidobacteria for their use as probiotics. However, the correlation of in vitro results with in vivo performance remains obscure.
To review the current state of evidence linking in vitro predictions to in vivo outcomes in selecting probiotic candidates and to discuss the advantages and limitations of the various assays presently available.
The successful use of lactobacilli and bifidobacteria as traditional probiotics is based on their occurrence in human milk, naturally fermented foods, in the gastrointestinal tract and feces of infants and adults as well as on their culturability, technological robustness and long history of safe use. The lack of standardized protocols for in vitro and in vivo studies hampers comparison of the potential of new species and strains. There is thus a need to conduct selection of potential probiotics in a more robust manner and to focus well-defined in vitro and in vivo studies to document health benefits.
•Lactobacilli and bifidobacteria are traditional probiotics based on their documented benefits and long history of safe use.•The value of in vitro tests as predictors of probiotic capacity is still uncertain.•There is a lack of standardized in vitro protocols for strain selection.•Nevertheless, present criteria allow narrowing down potential candidates when selecting new strains.
Cyclin dependent kinase A; 1 (CDKA; 1) is essential in G1/S transition of cell cycle and its oxidation has been implicated in cell cycle arrest during plant abiotic stress. In the present study, an ...evaluation at the molecular level was performed to find possible sites of protein oxidative modifications. In vivo studies demonstrated that carbonylation of maize CDKA,1 is associated with a decrease in complex formation with maize cyclin D (CycD). Control and in vitro oxidized recombinant CDKA; 1 were sequenced by mass spectrometry. Proline at the PSTAIRE cyclin-binding motif was identified as the most susceptible oxidation site by comparative analysis of the resulted peptides. The specific interaction between CDKA; 1 and CycD6; 1, measured by surface plasmon resonance (SPR), demonstrated that the affinity and the kinetic of the interaction depended on the reduced-oxidized state of the CDKA; 1. CDKA; 1 protein oxidative modification would be in part responsible for affecting cell cycle progression, and thus producing plant growth inhibition under oxidative stress.
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•Carbonylation of cyclin dependent kinase in vivo is associated with a decrease in complex formation with cyclin D (CycD).•CDKA; 1-CycD6; 1 interaction depends on the reduced -oxidized state of the CDKA; 1.•Proline from cyclin –binding motif of CDKA; 1 as a susceptible site for oxidation.
The complex formed by the cyclin-dependent kinase A (CDKA) and cyclin D is responsible for the G1-S transition in the plant cell cycle. Maize (Zea mays L) CDKA; 1 and CycD6; 1 were cloned and ...expressed in E. coli. The present study describes the optimization of both proteins production using a statistical approach known as response surface methodology (RSM). The experimental design took into account the effects of four variables: optical density of the culture (OD600) before induction, isopropyl β-d-1-thiogalactopyranoside (IPTG) concentration, post-induction temperature, and post-induction time. For each protein, a 24 full factorial central composite rotary design for these four independent variables (at five levels each) was employed to fit a polynomial model; which indicated that 30 experiments were required for this procedure. An optimization of CDKA; 1 and CycD6; 1 production levels in the soluble fraction was achieved. Protein conformation and stability were studied by circular dichroism and fluorescence spectroscopy. Finally, in vitro Cyc-CDK complex formation and its kinase activity were confirmed.
•Statistical optimization of maize recombinant CDKA; 1 and CycD6; 1 proteins production was performed in E coli.•Protein conformation and stability were established for both proteins.•Protein interactions and kinase activity of the complex were confirmed.
The diglycosidase α-rhamnosyl-β-glucosidase (EC 3.2.1.168) from the fungus Acremonium sp. DSM24697 was immobilized on several agarose-based supports. Covalent multipoint immobilization onto ...glyoxyl-activated agarose was selected as the more stable preparation at high concentration of dimethyl sulfoxide (DMSO) and high temperature. The optimal conditions for the immobilization process involved an incubation of the enzyme with agarose beads containing 220 μmol of glyoxyl groups per gram at pH 10 and 25°C for 24 h. The hydrolysis of hesperidin carried out in 10% v/v DMSO at 60°C for 2 h reached 64.6% substrate conversion and a specific productivity of 2.40 mmol h-1 g-1. Under these conditions, the process was performed reutilizing the catalyst for up to 18 cycles, maintaining >80% of the initial activity and a constant productivity 2.96 ± 0.42 µmol-1 h-1 g-1. To the best of our knowledge, such productivity is the highest achieved for hesperetin production through an enzymatic approach.
Excess weight in patients with cystic fibrosis: is it always beneficial? González Jiménez, David; Muñoz-Codoceo, Rosana; Garriga-García, María ...
Nutrición hospitalaria : organo oficial de la Sociedad Española de Nutrición Parenteral y Enteral,
06/2017, Letnik:
34, Številka:
3
Journal Article
Odprti dostop
The primary objective of this study was to find out the prevalence of overweight and obese status, as well as their association to pulmonary function, total cholesterol and vitamin D in patients with ...cystic fibrosis (CF).
This is a multicenter descriptive and cross-sectional study. Twelve Spanish hospitals participated. 451 patients with CF were included. Adults were classified according to body mass index (BMI) and children were classified according to BMI percentiles (WHO tables). Pearson's correlation, Anova, Student's t-test and multiple linear regression were conducted.
Mean age was 12.3 (range 4-57) years old, 51% were male and 18% had pancreatic sufficiency. Participants were classified in five nutritional status categories: 12% were malnourished; 57%, at nutritional risk; 24%, normally nourished; 6%, overweight; and 1%, obese. Pulmonary function in overweight or obese patients (91 ± 19%) was better than in malnourished patients (77 ± 24%) (p = 0.017). However, no difference was observed between those at nutritional risk (86 ± 19%) or normally nourished (90 ± 22%) groups. Overweight and obese patients had higher levels of total cholesterol (p = 0.0049), a greater proportion of hypercholesterolemia (p = 0.001), as well as lower levels of 25 OH vitamin D (p = 0.058).
Prevalence of overweight and obese was 6 and 1%. Excess weight status does not offer any benefit in pulmonary function in comparison to normally nourished patients.
Currently, dengue virus (DENV) infection is a world public health concern. In recent decades, three major outbreaks and a substantial growth of DENV infection prevalence have been observed in ...Argentina. However, there is a paucity of data on DENV epidemiology in this country.
To estimate DENV antibodies seroprevalence and determine the circulating serotypes in a population-based study.
Anti-DENV IgG antibodies were determined in 1,530 prospectively collected samples from blood donors throughout the country (April 2020 to April 2021). DENV serotyping was performed in 251 retrospectively analyzed samples (2016-2020).
Overall, anti-DENV IgG was detected in 220 (14.4%) blood donors. Seroprevalence was significantly higher in men (17.3%) than in women (11.3%), p <0.001. A higher seroprevalence was observed in the Northeast (24.0%), compared to the Center (12.9%) and Northwest (10.8%) regions, (p <0.001). Prevalence of DENV serotypes was 79.3% (n=199) for DENV-1, 0.8% (n=2) for DENV-2, and 19.9% (n=50) for DENV-4. DENV serotypes were unevenly distributed in samples from different outbreaks and regions.
This study provides new insights and updated data on the epidemiology of dengue in Argentina. The registered antibody seroprevalence is among the lowest one among Latin-American countries, raising cost-benefit objections with regards to massive vaccination policies. However, a high proportion of more than one circulating serotype should not be overlooked, as it is a warning of severe dengue possible increase in future Argentine outbreaks, which warrants close monitoring.
•This study provides new insights on dengue (DENV) epidemiology in argentina.•Anti-DENV IgG was detected in 220/1530 (14.4%) blood donors in argentina.•Seroprevalence was significantly higher in men (17.3%) than in women (11.3%).•Prevalence of DENV serotypes was 79.3% for DENV-1 and 19.9% for DENV-4.
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