To isolate and characterize bacteriophages, and to evaluate its lytic performance against avian pathogenic Escherichia coli (APEC) strains with high patterns of antibiotic resistance, in order to ...select phages for a therapeutic product to treat colibacillosis in chickens. Bacteriophages were isolated from poultry sewage and tested against 148 O-serotyped APEC strains. The morphological characterization of the bacteriophages was made by transmission electronic microscopy (TEM) observations and the genetic comparison between bacteriophages DNA was performed by restriction fragment length polymorphism (RFLP) patterns. Results showed that 70·5% of the tested E. coli strains were sensitive to a combination of three of the five isolated phages, that seemed to be virulent and taxonomically belong to the Caudovirales order. Two of them look like 16-19, T4-like phages (Myoviridae) and the third is a T1-like phage and belongs to Syphoviridae family. All of them are genetically different. It was possible to obtain a combination of three different lytic bacteriophages with broad lytic spectra against the most prevalent O-serotypes of APEC. Data reported in this study, presents an in vitro well studied phage product to be used as antimicrobial agent to treat colibacillosis in poultry industry.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Escherichia coli can cause severe respiratory and systemic infections in chickens, and it is often associated with significant economic losses in the poultry industry. Bacteriophages (phages) have ...been shown to be potential alternatives to the antibiotics in the treatment of bacterial infections. To accomplish that, phage particles must be able to reach and remain active in the infected organs. The present work aims at evaluating the effect of the route of administration and the dosage in the dissemination of 3 coliphages in the chicken's organs. In vivo trials were conducted by infecting chickens orally, spray, and i.m. with 10⁶, 10⁷, and 10⁸ plaque-forming units/mL suspensions of 3 lytic phages: phi F78E (Myoviridae), phi F258E (Siphoviridae), and phi F61E (Myoviridae). Birds were killed 3, 10, and 24 h after challenge and the phage titer was measured in lungs and air sacs membranes, liver, duodenum, and spleen. When administered by spray, the 3 phages reached the respiratory tract within 3 h. Oral administration also allowed all phages to be recovered in lungs, but only phi F78E was recovered from the duodenum, the liver, and the spleen. These differences can be explained by the possible replication of phi F78E in commensal E. coli strains present in the chicken gut, thus leading to a higher concentration of this phage in the intestines that resulted in systemic circulation of phage with consequent phage in organs. When phages were administered i.m., they were found in all of the collected organs. Despite this better response, i.m. administration is a nonpracticable way of protecting a large number of birds in a poultry unit. In general, the results suggest that oral administration and spray allowed phages to reach and to remain active in the respiratory tract and can, therefore, be considered promising administration routes to treat respiratory E. coli infections in the poultry industry.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Soil carbon sequestration has been recognized as an effective, low-cost technology to mitigate climate change. Simulation models, alone or in combination with soil sampling and other techniques, can ...help monitor changes in soil carbon levels as affected by climate, soil, and management conditions. The objective of this paper is to test the ability of the Environmental Policy Integrated Climate (EPIC) model to simulate total organic carbon (TOC) dynamics in soils of the central region of the Province of Córdoba (Argentina) and evaluate, through modeling, the capacity of Córdoba's agricultural soils to act as sources or sinks of atmospheric CO
2. We tested EPIC against measurements made in a spatially distributed 40-year chronosequence of a temperate shrubland forest transitioning to agricultural use with conventional practices and in two long-term tillage (moldboard plow, chisel plow, and no till) and crop rotation (maize
Zea mays L.–soybean
Glycine max L. Merr.) field studies. Overall, the EPIC model demonstrated a good capability for simulating TOC dynamics. In the chronosequence, the TOC lost during 40 years of cultivation after deforestation was calculated at 38.4
Mg
ha
−1 while that simulated by the model was 44.1
Mg
ha
−1. These values represented losses of 44% and 45% of the original TOC content, respectively. In the two long-term field experiments, the TOC simulated over the entire depth was close to the observed values and reflected the trends of the various treatments. For the most common conditions of croplands in Córdoba, crops grown in rotation with conservation tillage, particularly no till, would make soils act as sinks of atmospheric CO
2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We investigated the chemical and microbiological compositions of three types of whey to be used for kefir fermentation as well as the inhibitory capacity of their subsequent fermentation products ...against 100 Salmonella sp. and 100 Escherichia coli pathogenic isolates. All the wheys after fermentation with 10% (wt/vol) kefir grains showed inhibition against all 200 isolates. The content of lactic acid bacteria in fermented whey ranged from 1.04 × 10(7) to 1.17 × 10(7) CFU/ml and the level of yeasts from 2.05 × 10(6) to 4.23 × 10(6) CFU/ml. The main changes in the chemical composition during fermentation were a decrease in lactose content by 41 to 48% along with a corresponding lactic acid production to a final level of 0.84 to 1.20% of the total reaction products. The MIC was a 30% dilution of the fermentation products for most of the isolates, while the MBC varied between 40 and 70%, depending on the isolate. The pathogenic isolates Salmonella enterica serovar Enteritidis 2713 and E. coli 2710 in the fermented whey lost their viability after 2 to 7 h of incubation. When pathogens were deliberately inoculated into whey before fermentation, the CFU were reduced by 2 log cycles for E. coli and 4 log cycles for Salmonella sp. after 24 h of incubation. The inhibition was mainly related to lactic acid production. This work demonstrated the possibility of using kefir grains to ferment an industrial by-product in order to obtain a natural acidic preparation with strong bacterial inhibitory properties that also contains potentially probiotic microorganisms.
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CEKLJ, GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
1. Bacteriophage (phage) crude lysate of Gram-negative bacteria often contains bacterial debris, including lipopolysaccharides found in the outer membrane of the cell wall, which are potentially ...toxic. 2. In this study, an in vivo evaluation of the toxicity of a suspension of three phages to control pathogenic Escherichia coli strains in poultry was performed. 3. Eighteen commercial layers, 7 weeks old, were intramuscularly injected with phage lysate (8.21 x 10(4) Endotoxin Units/dose). The control group was injected with sterile Luria Bertani (LB) broth. 4. Bird prostration and decrease in body weight gain and water intake per gram of body weight were observed only on the day of the inoculation in the challenged group. Over the following 6 d, no differences were observed in the chickens' activity. 5. These results support the view that phage crude lysate carrying endotoxins are not toxic for chickens.
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Spatial sampling density influences the reliability and feasibility of environmental studies. Optimizing spatial sampling schemes is important, particularly when multiple observations must be ...repeated over extended periods.
The goal of this study was to develop a sampling density reduction method for a network of 57 soil water content (SWC) measurement locations in an 8-ha microwatershed, given observations taken at five different dates. We sought a subset of 10 points that would best predict (via spatial interpolation) the SWC at the remaining locations.
Three observation dates (calibration set) were used to develop the method, and the remaining two (validation set) were used to test it. Calibration date semivariograms were coalesced into one scaled semivariogram, used with ordinary kriging to predict SWC outside the chosen subset. We defined four different scenarios by combining two simulated annealing algorithms, Sacks and Schiller (S&S) and Spatial Simulated Annealing (SSA), and two fitness functions, one based on scaled kriging variance (SKV), and the other based on actual mean squared prediction error (scaled mean squared error, SMSE).
We searched for an optimal subset in each calibration scenario; each was then used to predict SWC throughout the microwatershed on the validation dates. The results were compared with those of regular grids and randomly generated patterns. Temporal stability was tested by analyzing deviations between individual and field average observations and using Spearman's rank correlation.
The S&S and SSA algorithms performed similarly well, although SSA converged better. The SKV-based scenarios had lower SKV in the calibration and validation sets than the SMSE-based scenarios, the regular grids, and the random patterns. However, the SMSE-based scenarios produced an optimal subset having minimal SMSE over both data sets vs. the other methods. This subset produced mostly low relative errors: for January 25, 1993, 50% of the predicted points fell within ±5%, 82% within ±10%, and 6.5% fell outside 15%; for December 23, 1993, 35% were within ±5%, 72% within ±10%, and 23% fell beyond 15%. However, kriging assumptions were violated on December 23.
The SMSE-based scenarios predicted validation set SWC better than the SKV scenarios because they included microwatershed locations that did not obey the stationarity assumptions of kriging but were temporally stable and captured the full range of SWC variation. Modifying the proposed method to perform kriging with a physically based trend model will further improve its predictive accuracy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study was carried out: (i) to estimate from soil water depletion curves the apparent rooting depth (RD) for several crops; (ii) to calculate the soil water extraction parameters; and (iii) to ...compare inter- and intraspecific differences in the water extraction parameters. Experiments were conducted at the Manfredi Experimental Station (INTA), Argentina (31°49′S, 63°48′W), and at the Institute of Phytopathology and Vegetal Physiology (IFFIVE), Cordoba, Argentina (31°24′S, 64°11′W). The soil was a silty loam Entic Haplustoll (USDA Soil Taxonomy) with A, AC and C horizons. The crops studied were: maize (
Zea mays L.), sunflower (
Helianthus annuus L.), peanut (
Arachis hypogaea L.), soybean (
Glycine max L. Merr.), and alfalfa (
Medicago sativa L.). Differences in apparent rooting depths among species and cultivars, ranging from 130 to 290 cm, were found. The comparison of the extraction front velocity (EFV) revealed differences among species but not among cultivars of the same species. EFV ranged from 44 mm day
−1 for sunflower to 23 mm day
−1 for peanut. In all the crops, the downward progress of the extraction front stopped at the beginning of the grain filling. Comparisons among the pooled rates of water extraction (
kl) for depths from 10 to 110 cm, revealed significant differences among crops and cultivars within crops. The
kl values ranged from 0.110 day
−1 for Contiflor 3 sunflower to 0.029 day
−1 for alfalfa. No significant correlation between
kl values and root length density over 40 to 120 cm depths was found for soybean, indicating that the specific water uptake rate varies considerably in the soil profile.
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Our objective was to analyze temporal trends in the prevalence of self-reported hypertension among Brazilian adults and to investigate differences in health behaviors between individuals with and ...without hypertension between 2006 and 2019. Data from the Surveillance System for Risk Factors and Protection for Chronic Diseases by Telephone Survey were analyzed (n = 730,309). Prais–Winsten regression was used to identify linear trends in the prevalence of hypertension for the entire period (2006–2019) and for the past 5 years. Poisson regression models were used to investigate the differences in health behaviors among individuals with and without hypertension. The prevalence of hypertension (approximately 24.0%) remained stable from 2006 to 2019 and decreased from 25.1% to 24.6% from 2015 to 2019. In the adjusted analyses, individuals with hypertension showed a significant association with unhealthy lifestyle habits: lower recommended intake of fruits and vegetables (APR = 0.97; p = 0.022), lower regular intake of fruits (APR = 0.98; p < 0.001), lower regular intake of beans (APR = 0.97; p < 0.001), lower leisure-time exercising (APR = 0.89; p < 0.001), higher abusive consumption of alcoholic beverages (APR = 1.04; p = 0.004), higher prevalence of overweight (APR = 1.40; p < 0.001), and higher prevalence of obesity (APR = 2.17; p < 0.001). Hypertension prevalence has remained stable during the entire period and decreased in the most recent period. Individuals with hypertension reported unfavorable scenarios for healthy habits.
In Argentina, peanut production is concentrated in areas where unpredictable and intermittent periods of water deficit occur almost every year especially, during the pod growth period. Florman INTA ...is the most popular variety among peanut producers, but it is highly sensitive to drought. Manfredi 393 INTA was released as a drought-tolerant variety. Differences between these varieties in radiation interception and crop mass accumulation relative to light levels, as well as in allocation of assimilate to economic yield under water deficit, have not been previously studied.
An experiment was set with two different regimes of water supply. Half of the crop was irrigated (IRR) from sowing to maturity, while the other half received no water between 47 and 113 days after sowing. The fraction of PAR intercepted, (
f), leaf area, pod and vegetative above-ground biomass and leaf carbon dioxide exchange rate (CER) were measured periodically during the water deficit period. The leaf area index, degree of leaf folding, canopy extinction coefficient, radiation use efficiency (RUE), partitioning factor, (
p), and harvest index (HI) were calculated from the measurements.
Under water stress,
f was reduced in both varieties with respect to their controls, and the reduction was proportionally higher in Florman INTA as a consequence of a higher leaf area reduction and degree of leaf folding. However,
f remained higher in Florman INTA than in Manfredi 393 INTA due to the enhanced capacity of the former to generate leaf area under non-limiting water supply.
RUE values were higher in Manfredi 393 INTA than in Florman INTA, both under irrigation as well as under severe water deficit, where they were obtained using a two-parameter exponential model. The reason for the higher RUE values in Manfredi 393 INTA was its ability to maintain a higher leaf CER.
Partitioning to pods under irrigation was greater in Manfredi 393 INTA than in Florman INTA, as a result of a longer pod filling period and higher
p. Towards the end of podfill, there was a rapid increase of
p in Florman INTA, but too late to improve its HI. Under water stress, the time course of
p for both varieties was lower than in the IRR treatments and consequently, HI at harvest was reduced. Low HI values could be attributed to some extent to the mechanical impedance of the upper soil layer, caused by water deficit. Mechanical impedance alters the relation among
p and HI values obtained under irrigation and water stress. However, even if it is accounted for, cultivars with high HI under IRR conditions usually have high HI under water deficit.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The water extraction capability and water use efficiency (WUE) of two argentine peanut varieties Florman INTA and Manfredi 393 INTA, respectively classed as drought-sensitive and drought-tolerant ...were compared. The experiment was grown at two different regimes of water supply. Between 47 and 113 days after sowing (DAS) half of the crop was irrigated, while the other half received no water. Soil water contents, canopy temperature, above ground dry matter and root length density (RLD) were measured periodically during the drought period. Water use (WU), stress degree day (SDD), extraction front velocity (EFV), uptake coefficient, shoot and pod water use efficiency corrected (WUE
c) by vapor pressure deficit, and soil resistance were calculated from the measurements.
Manfredi 393 INTA had a higher WU than Florman INTA in both irrigated (IRR) and water-stressed (WS) treatments. This was linked to a higher transpiration rate as demonstrated by SDD time course values. The EFV obtained from lineal and logistic fitted models showed a similar pattern for both varieties. However, the logistic function fitted better than the linear model. The observed differences in WU under drought were explained by slightly but consistently higher uptake coefficient values in Manfredi 393 INTA. Uptake coefficient differences between varieties were not associated with RLD; thus, it was not useful as an indicator of the genotypic ability to extract soil water.
Florman INTA possessed higher WUE
c than Manfredi 393 INTA in both IRR and WS treatments. On the other hand, these differences between varieties were not observed for pod WUE
c. Both varieties showed similar values under the irrigated regime because the higher WU on Manfredi 393 INTA was compensated for a higher pod production due to an enhanced partitioning of assimilates to pods. Under WS regime, pod WUE
c was significantively reduced in both varieties. The mechanical impedance in the soil upper layer contributed to this reduction. Although critical soil resistance was similar for the two varieties under study, its effect was remarkable on Florman INTA due to a delay in the onset of the beginning pod stage and non-synchronous reproductive development. Manfredi 393 INTA demonstrated an adaptative advantage to drought, expressed in its higher pod production, due to either an earlier onset of beginning peg stage that affected differentially peg penetration into the dry soil upper layer, and an enhanced partitioning of assimilates to pods.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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