National University of Santiago del Estero

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

BACKGROUND: A century after its discovery, Chagas disease still represents a major neglected tropical threat. Accurate diagnostics tools as well as surrogate markers of parasitological response to treatment are research priorities in the field. The purpose of this study was to evaluate the performance of PCR methods in detection of Trypanosoma cruzi DNA by an external quality evaluation. METHODOLOGY/FINDINGS: An international collaborative study was launched by expert PCR laboratories from 16 countries. Currently used strategies were challenged against serial dilutions of purified DNA from stocks representing T. cruzi discrete typing units (DTU) I, IV and VI (set A), human blood spiked with parasite cells (set B) and Guanidine Hidrochloride-EDTA blood samples from 32 seropositive and 10 seronegative patients from Southern Cone countries (set C). Forty eight PCR tests were reported for set A and 44 for sets B and C; 28 targeted minicircle DNA (kDNA), 13 satellite DNA (Sat-DNA) and the remainder low copy number sequences. In set A, commercial master mixes and Sat-DNA Real Time PCR showed better specificity, but kDNA-PCR was more sensitive to detect DTU I DNA. In set B, commercial DNA extraction kits presented better specificity than solvent extraction protocols. Sat-DNA PCR tests had higher specificity, with sensitivities of 0.05-0.5 parasites/mL whereas specific kDNA tests detected 5.10(-3) par/mL. Sixteen specific and coherent methods had a Good Performance in both sets A and B (10 fg/µl of DNA from all stocks, 5 par/mL spiked blood). The median values of sensitivities, specificities and accuracies obtained in testing the Set C samples with the 16 tests determined to be good performing by analyzing Sets A and B samples varied considerably. Out of them, four methods depicted the best performing parameters in all three sets of samples, detecting at least 10 fg/µl for each DNA stock, 0.5 par/mL and a sensitivity between 83.3-94.4%, specificity of 85-95%, accuracy of 86.8-89.5% and kappa index of 0.7-0.8 compared to consensus PCR reports of the 16 good performing tests and 63-69%, 100%, 71.4-76.2% and 0.4-0.5, respectively compared to serodiagnosis. Method LbD2 used solvent extraction followed by Sybr-Green based Real time PCR targeted to Sat-DNA; method LbD3 used solvent DNA extraction followed by conventional PCR targeted to Sat-DNA. The third method (LbF1) used glass fiber column based DNA extraction followed by TaqMan Real Time PCR targeted to Sat-DNA (cruzi 1/cruzi 2 and cruzi 3 TaqMan probe) and the fourth method (LbQ) used solvent DNA extraction followed by conventional hot-start PCR targeted to kDNA (primer pairs 121/122). These four methods were further evaluated at the coordinating laboratory in a subset of human blood samples, confirming the performance obtained by the participating laboratories. CONCLUSION/SIGNIFICANCE: This study represents a first crucial step towards international validation of PCR procedures for detection of T. cruzi in human blood samples.

Antimicrobial peptides (AMPs) are promising novel antibiotics since they have shown antimicrobial activity against a wide range of bacterial species, including multiresistant bacteria; however, toxicity is the major barrier to convert antimicrobial peptides into active drugs. A profound and proper understanding of the complex interactions between these peptides and biological membranes using biophysical tools and model membranes seems to be a key factor in the race to develop a suitable antimicrobial peptide therapy for clinical use. In the search for such therapy, different combined approaches with conventional antibiotics have been evaluated in recent years and demonstrated to improve the therapeutic potential of AMPs. Some of these approaches have revealed promising additive or synergistic activity between AMPs and chemical antibiotics. This review will give an insight into the possibilities that physicochemical tools can give in the AMPs research and also address the state of the art on the current promising combined therapies between AMPs and conventional antibiotics, which appear to be a plausible future opportunity for AMPs treatment.

Plants subjected to postharvest abiotic stresses synthesize secondary metabolites with health-promoting properties. Here, we report the potential use of carrots (Daucus carota) as biofactories of caffeoylquinic acids when subjected to wounding and hyperoxia stresses. Wounding stress induced an increase of ∼287% in total phenolic content (PC) in carrots stored for 48 h at 20 °C. This increase was higher (∼349%) in the wounded tissue treated with hyperoxia stress. To further understand the physiological role of reactive oxygen species (ROS) as a signaling molecule for the stress-induced accumulation of phenolics in carrots, the respiration rate as well as the enzymatic activities of NADPH oxidase, superoxide dismutase, ascorbate peroxidase, and catalase were evaluated. Likewise, shredded carrots were treated with diphenyleneiodonium chloride solution to block NADPH oxidase ROS productions, and the phenylalanine ammonia lyase activity and total PC were evaluated. Results demonstrated that ROS play a key role as a signaling molecule for the stress-induced accumulation of PC in carrots.

Abstract Physiological responses to salt stress were investigated in two cotton (Gossypium hirsutum L.) cultivars (Pora and Guazuncho) grown hydroponically under various concentrations of NaCl. Dry matter partitioning, plant water relations, mineral composition and proline content were studied. Proline and inorganic solutes were measured to determine their relative contribution to osmotic adjustment. Both leaf water potential (Ψw) and osmotic potential (Ψs)decreased in response to NaCl levels. Although Ψwand Ψs decreased during salt stress, pressure potential Ψp remained between 0.5 to 0.7 MPa in control and all NaCl treatments, even under 200 mol m−3 NaCl. Increased NaCl levels resulted in a significant decrease in root, shoot and leaf growth biomass. Root / shoot ratio increased in response to salt stress. The responses of both cultivars to NaCl stress were similar. Increasing salinity levels increased plant Na+ and Cl−. Potassium level remained stable in the leaves and decreased in the roots with increasing salinity. Salinity decreased Ca2+ and Mg2+ concentrations in leaves but did not affect the root levels of these nutrients. The K/Na selectivity ratio was much greater in the saline treated plants than in the control plants. Osmotic adjustment of roots and leaves was predominantly due to Na+ and Cl− accumulation; the contribution of proline to the osmotic adjustment seemed to be less important in these cotton cultivars. ACKNOWLEDGMENTS This work is part of a M.S. Thesis by D.A.M., Federal University of Viçosa, Brazil 1998. D.A.M. was supported by a scholarship from CICyT-U.N.S.E., Argentina, and partially by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brasil). The authors gratefully acknowledge the contributions of Dr. Moacyr Maestri for critical reading of the manuscript.

Prosopis alba (algarrobo) is one of the most important salt-tolerant legumes used in the food and furniture industries. The effects of salinity on some growth and physiological parameters in algarrrobo seedlings were investigated. 17-Day-old seedlings were subjected to three salt treatments by adding NaCl to the growth medium in 50 mmol.L-1 increments every 24 h until the final concentrations of 0, 300 and 600 mmol.L-1 were reached. Only the highest NaCl concentration affected all of the considered parameters. Thus, 600 mmol.L-1 NaCl caused a significant reduction in root and shoot growth, but an increase in the root/shoot ratio. Leaf relative water content, nitrate content and nitrate reductase activity in leaves and roots were also decreased. At 300 and 600 mmol.L-1, the glycinebetaine content was significantly increased in both leaves and roots but this was not found for proline content. Total soluble carbohydrates increased only in roots. The results suggest that glycinebetaine enhancement may be important for osmotic adjustment in Prosopis alba under salinity stress.

Metallo-β-lactamases (MBLs) hydrolyze almost all β-lactam antibiotics and are unaffected by clinically available β-lactamase inhibitors (βLIs). Active-site architecture divides MBLs into three classes (B1, B2, and B3), complicating development of βLIs effective against all enzymes. Bisthiazolidines (BTZs) are carboxylate-containing, bicyclic compounds, considered as penicillin analogs with an additional free thiol. Here, we show both l- and d-BTZ enantiomers are micromolar competitive βLIs of all MBL classes in vitro, with Kis of 6-15 µM or 36-84 µM for subclass B1 MBLs (IMP-1 and BcII, respectively), and 10-12 µM for the B3 enzyme L1. Against the B2 MBL Sfh-I, the l-BTZ enantiomers exhibit 100-fold lower Kis (0.26-0.36 µM) than d-BTZs (26-29 µM). Importantly, cell-based time-kill assays show BTZs restore β-lactam susceptibility of Escherichia coli-producing MBLs (IMP-1, Sfh-1, BcII, and GOB-18) and, significantly, an extensively drug-resistant Stenotrophomonas maltophilia clinical isolate expressing L1. BTZs therefore inhibit the full range of MBLs and potentiate β-lactam activity against producer pathogens. X-ray crystal structures reveal insights into diverse BTZ binding modes, varying with orientation of the carboxylate and thiol moieties. BTZs bind the di-zinc centers of B1 (IMP-1; BcII) and B3 (L1) MBLs via the free thiol, but orient differently depending upon stereochemistry. In contrast, the l-BTZ carboxylate dominates interactions with the monozinc B2 MBL Sfh-I, with the thiol uninvolved. d-BTZ complexes most closely resemble β-lactam binding to B1 MBLs, but feature an unprecedented disruption of the D120-zinc interaction. Cross-class MBL inhibition therefore arises from the unexpected versatility of BTZ binding.

The capacity of polyphenolic compounds to reduce the beta-carotene-linoleic acid cooxidation enzymatically induced by soybean lipoxygenase was assayed to determine their comprehensive antioxidant ability. The inhibition of the coupled oxidation is a well-known spectrophotometric method for the antioxidant activity measurement. A modification of this method is proposed to reduce assay time and to gain simplicity. The antioxidant abilities of several polyphenols were determined, and quercetin and sinapic acid were most active. These results were compared to those obtained by the DPPH* procedure to evaluate the free radical scavenging contribution to the total protective action. The highest values of antiradical activity were found for ellagic and quercetin.

Twelve alfalfa genotypes that were selected for biomass under salinity, differences in Na and Cl concentrations in shoots and K/Na ratio were evaluated in this long-term salinity experiment. The selected plants were cloned to reduce genetic variability within each genotype. Salt tolerance (ST) index of the genotypes ranged from 0.39 to 1. The most salt-tolerant genotypes SISA14-1 (G03) and AZ-90ST (G10), the top performers for biomass, exhibited the least effect on shoot number and height. SISA14-1 (G03) accumulated low Na and Cl under salinity. Most genotypes exhibited a net reduction in shoot Ca, Mg, P, Fe, and Cu, while Mn and Zn increased under salinity. Salinity reduced foliar area and stomatal conductance; while net photosynthetic rate and transpiration were not affected. Interestingly, salinity increased chlorophyll and antioxidant capacity in most genotypes; however neither parameter correlated well to ST index. Salt-tolerant genotypes showed upregulation of the SOS1, SOS2, SOS3, HKT1, AKT1, NHX1, P5CS1, HSP90.7, HSP81.2, HSP71.1, HSPC025, OTS1, SGF29 and SAL1 genes. Gene expression analyses allowed us to classify genotypes based on their ability to regulate different components of the salt tolerance mechanism. Pyramiding different components of the salt tolerance mechanism may lead to superior salt-tolerant alfalfa genotypes.

The highest yield (14.4 g/kg) of naringin, the major flavonoid from the peel of Citrus paradisi L., that could be achieved by supercritical fluid extraction was obtained using supercritical carbon dioxide modified with 15% ethanol and fresh (rather than dried) peels at 95 bar and 58.6 degrees C. This yield is higher than that attained by the conventional technique of maceration, and close to those obtained by reflux and Soxhlet methods. Furthermore, supercritical fluid extraction consumes less solvent and provides a shorter extraction time than conventional extraction methods.

Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the follicle is made. Follicular growth during this period is tightly regulated by oocyte-granulosatheca cell interactions. A cluster of early expressed genes is required for normal folliculogenesis. Granulosa cell factors stimulate the recruitment of theca cells from cortical stromal cells. Thecal factors promote granulosa cell proliferation and suppress granulosa cell apoptosis. Cell-cell and cell-extracellular matrix interactions influence the production of growth factors in the different follicular compartments (oocyte, granulosa, and theca cells). Several autocrine and paracrine factors are involved in follicular growth and differentiation; their activity is present even at the time of ovulation, decreasing the gap junction communication, and stimulating the theca cell proliferation. In addition, the identification of the factors that promote follicular growth from the preantral stage to the small antral stage may provide important information for the identification for assisted reproduction techniques.

BACKGROUND: Spironolactone, an aldosterone antagonist, has been demonstrated to decrease mortality in human patients when added to other cardiac therapies. HYPOTHESIS: Spironolactone in addition to conventional therapy increases survival compared with conventional therapy in dogs with naturally occurring myxomatous mitral valve disease (MMVD). ANIMALS: Between February 2003 and March 2005, 221 dogs were recruited in Europe. Nine dogs were excluded from analysis, leaving 212 dogs with moderate to severe mitral regurgitation (MR) caused by MMVD (International Small Animal Cardiac Health Council classification classes II [n = 190] and III [n = 21]). METHODS: Double-blinded, field study conducted with dogs randomized to receive either spironolactone (2 mg/kg once a day) or placebo in addition to conventional therapy (angiotensin converting enzyme inhibitor, plus furosemide and digoxin if needed). Primary endpoint was a composite of cardiac-related death, euthanasia, or severe worsening of MR. RESULTS: Primary endpoint reached by 11/102 dogs (10.8%) in the spironolactone group (6 deaths, 5 worsening) versus 28/110 (25.5%) in control group (14 deaths, 8 euthanasia, 6 worsening). Risk of reaching the composite endpoint significantly decreased by 55% (hazard ratio [HR] = 0.45; 95% confidence limits [CL], 0.22-0.90; log rank test, P = .017). Risk of cardiac-related death or euthanasia significantly reduced by 69% (HR = 0.31; 95% CL, 0.13-0.76; P = .0071). Number of dogs not completing the study for cardiac and other miscellaneous reasons similar in spironolactone (67/102) and control groups (66/110). CONCLUSION AND CLINICAL IMPORTANCE: Spironolactone added to conventional cardiac therapy decreases the risk of reaching the primary endpoint (ie, cardiac-related death, euthanasia, or severe worsening) in dogs with moderate to severe MR caused by MMVD.

Intestinal and free-living protozoa, such as Giardia lamblia, express a dense coat of variant-specific surface proteins (VSPs) on trophozoites that protects the parasite inside the host's intestine. Here we show that VSPs not only are resistant to proteolytic digestion and extreme pH and temperatures but also stimulate host innate immune responses in a TLR-4 dependent manner. We show that these properties can be exploited to both protect and adjuvant vaccine antigens for oral administration. Chimeric Virus-like Particles (VLPs) decorated with VSPs and expressing model surface antigens, such as influenza virus hemagglutinin (HA) and neuraminidase (NA), are protected from degradation and activate antigen presenting cells in vitro. Orally administered VSP-pseudotyped VLPs, but not plain VLPs, generate robust immune responses that protect mice from influenza infection and HA-expressing tumors. This versatile vaccine platform has the attributes to meet the ultimate challenge of generating safe, stable and efficient oral vaccines.

Strawberries represent an important source of bioactive compounds due to their vitamin C and phenolic compound levels, which present high antioxidant effects, beneficial for the maintenance of consumer’s health. Argentina is the second largest strawberry producer in The Common Market of the Southern Cone (MERCOSUR), covering the main export destinations of Argentinian strawberries, i.e., Canada, United States, and European Union. Information about the bioactive compound occurrence and antioxidant capacity of these fruits is scarce or not available. Health related compounds of strawberry cultivars (Camarosa and Selva) from different zones of Argentina were investigated. Vitamin C content was in the same range for both studied cultivars. However, Camarosa strawberries, which are the most cultivated, consumed, and exported berries in Argentina, presented higher total phenolic and anthocyanins content, and consequently better in vitro antioxidant capacity. Moreover, there were differences in the occurrence and concentration in the phenolic compound profiles for both cultivars. Camarosa cultivar presented higher content of anthocyanidins, and Selva showed higher total ellagic acid content. The research shows that Argentina’s strawberries are an interesting source of bioactive compounds comparable to those in other parts of the world.

Because of the recent presence of Helicoverpa armigera in Brazil and Paraguay in 2013, pheromone traps were deployed in chickpea crops at 2 localities in Tucumán province to determine if this noctuid was present in Argentina. This pest was detected at both locations, confirming the presence of H. armigera in Argentina for first time.

Changes in crop yields and bioactive substance contents were studied in lettuce crop concerning the influence of soil nutritional status as a result of compost and vermicompost additions obtained from different organic substrates. Plant productions and main pigment contents in lettuce were higher in all the fertilized soils than in the untreated soil, with the exception of the one treated with urban solid waste compost. These positive effects correlate with nitrogen level increase in soil. However, the high saline input of this compost prepared from food home wastes interferes in lettuce growth and prevents it from being higher than the control. Marked decreases in lettuce phenolic contents and antiradical activity were found in most of the treatments. Composts and vermicomposts produced through the processing of cattle manures, agro-industrial organic wastes significantly increased lettuce crop yield enriching its pigment contents, although, in some cases, antioxidant value and phenolic levels were reduced.

Bacteriophages can cause great economic losses due to fermentation failure in dairy plants. Hence, physical and chemical treatments of raw material and/or equipment are mandatory to maintain phage levels as low as possible. Regarding thermal treatments used to kill pathogenic bacteria or achieve longer shelf-life of dairy products, neither low temperature long time nor high temperature short time pasteurization were able to inactivate most lactic acid bacteria (LAB) phages. Even though most phages did not survive 90°C for 2 min, there were some that resisted 90°C for more than 15 min (conditions suggested by the International Dairy Federation, for complete phage destruction). Among biocides tested, ethanol showed variable effectiveness in phage inactivation, since only phages infecting dairy cocci and Lactobacillus helveticus were reasonably inactivated by this alcohol, whereas isopropanol was in all cases highly ineffective. In turn, peracetic acid has consistently proved to be very fast and efficient to inactivate dairy phages, whereas efficiency of sodium hypochlorite was variable, even among different phages infecting the same LAB species. Both alkaline chloride foam and ethoxylated non-ylphenol with phosphoric acid were remarkably efficient, trait probably related to their highly alkaline or acidic pH values in solution, respectively. Photocatalysis using UV light and TiO(2) has been recently reported as a feasible option to industrially inactivate phages infecting diverse LAB species. Processes involving high pressure were barely used for phage inactivation, but until now most studied phages revealed high resistance to these treatments. To conclude, and given the great phage diversity found on dairies, it is always advisable to combine different anti-phage treatments (biocides, heat, high pressure, photocatalysis), rather than using them separately at extreme conditions.

Gum Arabic (GA) or Acacia gum is an edible biopolymer obtained as exudates of mature trees of Acacia senegal and Acacia seyal which grow principally in the African region of Sahe in Sudan. The exudate is a non-viscous liquid, rich in soluble fibers, and its emanation from the stems and branches usually occurs under stress conditions such as drought, poor soil fertility, and injury (Williams & Phillips, 2000).

BACKGROUND: The high success rate of dental implants has changed the quality of life for many patients. Immediate loading finds its application in some clinical cases and certainly adds another modality of treatment for the implant patient. Starting with a few implants immediately loaded with a bar overdenture in the mandible, the concept of immediate loading evolved to loading multiple implants in both the maxilla and mandible. METHODS: In this investigation, 41 consecutive patients who needed full-arch restorations were treated with 343 double acid-etched surface implants between May 1998 and March 2004. The sample included smokers and bruxers. Twenty-three mandibular and 26 maxillary cases were treated, loading the implants within 48 hours, by using resin provisional prostheses, metal-reinforced provisional prostheses, or definitive prostheses (metal-acrylic or metal-ceramic). All implants were followed for 12 to 74 months. Follow-up consisted of clinical as well as radiographic examination. Furthermore, resonance frequency analysis was done in most of the implants during the last 2 years. RESULTS: The success rate obtained was 99.42% (only two mandibular implants that are still surviving were considered failures). The bone level was measured every year. The average radiographic bone level change was 0.56 mm at 12, 0.76 mm at 24, 0.84 mm at 36, 0.82 mm at 48, 0.83 mm at 60, and 0.94 mm at 72 months. CONCLUSION: A high success rate can be achieved when double acid-etched surface implants are immediately loaded with fixed full-arch restorations in the maxilla and mandible.

The photodynamic activities of the free-base 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin (TMP) and their metal complexes with zinc(II) (ZnTMP), copper(II) (CuTMP) and cadmium(II) (CdTMP) have been compared in two systems: reverse micelle of n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate/water bearing photooxidizable substrates and Hep-2 human larynx carcinoma cell line. The quantum yields of singlet molecular oxygen, O2(1 delta g), production (phi delta) of TMP, ZnTMP and CdTMP in tetrahydrofuran, were determined yielding values of 0.65, 0.73 and 0.73, respectively, while O2(1 delta g) formation was not detected for CuTMP. In the reverse micellar system, the amino acid L-tryptophan (Trp) was used as biological substrate to analyze the O2(1 delta g)-mediated photooxidation. The observed rate constants for Trp photooxidation (kobsTrp) were proportional to the sensitizer quantum yield of O2(1 delta g). A value of approximately 2 x 10(7) s-1 M-1 was found for the second-order rate constant of Trp (krTry) in this system. The response of Hep-2 cells to cytotoxicity photoinduced by these agents in a biological medium was studied. The Hep-2 cultures were treated with 1 microM of porphyrin for 24 h at 37 degrees C and the cells exposed to visible light. The cell survival at different light exposure levels was dependent on phi delta. Under these conditions, the cytotoxic effect increases in the order: Cu-TMP << TMP < ZnTMP approximately CdTMP, correlating with the production of O2(1 delta g). A similar behavior was observed in both the chemical and biological media indicating that the O2(1 delta g) mediation appears to be mainly responsible for the cell inactivation.