Aedes aegypti (Diptera: Culicidae) Longevity and Differential Emergence of Dengue Fever in Two Cities in Sonora, Mexico.

Dengue virus, primarily transmitted by the Aedes aegypti (L.) mosquito, has rapidly expanded in geographic extent over the past several decades. In some areas, however, dengue fever has not emerged despite established Ae. aegypti populations. The reasons for this are unclear and have sometimes been attributed to socio-economic differences. In 2013 we compared Ae. aegypti adult density and population age structure between two cities in Sonora, Mexico: Hermosillo, which has regular seasonal dengue virus transmission, and Nogales, which has minimal transmission. Larval and pupal abundance was greater in Nogales, and adult density was only higher in Hermosillo during September. Population age structure, however, was consistently older in Hermosillo. This difference in longevity may have been one factor that limited dengue virus transmission in Nogales in 2013, as a smaller proportion of Ae. aegypti females survived past the extrinsic incubation period.

Síndrome del cíclope: hallazgo sin el antecedente quirúrgico de ligamento cruzado anterior / Cyclops syndrome: finding no surgical history ACL

La presencia de un nódulo fibrovascular llamado cíclope, a nivel del espacio intercondíleo anterior, es un hallazgo ampliamente descrito en la literatura médica como una complicación en casos con antecedente de reconstrucción del ligamento cruzado anterior (LCA). Sin embargo, como sucedió en nuestro paciente, en la actualidad se han comunicado algunos pocos casos con injuria del LCA y lesión cíclope, pero sin el antecedente quirúrgico. Nuestro paciente tuvo un trauma directo en su rodilla seis meses antes de la consulta médica y una injuria del LCA, que podrían haber estado vinculados con la etiopatogenia de la formación de un nódulo fibroso. En el examen físico se observó una limitación en la extensión de la rodilla y en la resonancia magnética (RM), una formación redondeada bien definida, en íntimo contacto con el LCA desgarrado, correspondiente a síndrome cíclope.

The presence of a fibrovascular nodule called Cyclops at the level of anterior intercondylar space, is a finding widely described in the literature as a complication in patients with previous anterior cruciate ligament reconstruction (ACL). However, at present, it has been described some patients with ACL injury and cyclops lesión but without surgical history, as in our case. Our patient had a history of direct trauma in his knee six months before medical consultaron, which could be linked to the pathogenesis of fibrous nodule formation. On physical examination, there was a limitation on the extensión of the knee and a well defined rounded neoformation, closed to the torn ACL corresponding to Cyclops syndrome was observed with magnetic resonance imaging (MRI).

Soybean fungal soil-borne diseases: a parameter for measuring the effect of agricultural intensification on soil health.

The aim of this study was to investigate the influence of agricultural intensification on soil microbial diversity, chemical and physical parameters, and the decrease of the incidence of sudden death syndrome (Fusarium crassistipitatum) and charcoal rot (Macrophomina phaseolina) in soybean. Soils under different management systems were evaluated during 2 crop cycles: soybean monoculture for 24 and 11 years, soybean-maize rotation for 15 and 4 years, 1 year of soybean, and native vegetation. The incidence of both soil-borne diseases was higher under monoculture than under rotation. Increased populations of potential biocontrol agents (Trichoderma spp., Gliocladium spp., fluorescent pseudomonads) were associated with rotation treatments, especially in 2010-2011. The comparison of agricultural vs. native vegetation soil and the average of agricultural cycles showed that microbial biomass carbon and glomalin-related soil protein were higher in the rotation system than in monoculture (50% and 77%, respectively). Furthermore, from the community-level functional diversity (Biolog Eco plates), McIntosh index showed lower functional diversity in monoculture than in rotation and native vegetation plots. Agricultural intensification reduced microbial biomass carbon, glomalin-related soil protein, organic matter, total nitrogen, aggregate stability, and yield, and increased bulk density. Soil quality degradation was associated with the establishment of soil-borne pathogens and increased soybean plant susceptibility to disease.

First Molecular Detection of Ramularia Leaf Spot (Ramularia collo-cygni) in Seeds and Leaves of Barley in Argentina.

The fungus Ramularia collo-cygni B. Sutton & J. M. Waller (Rcc) was identified as the causal agent of this emerging disease on barley (Hordeum vulgare L.) based on symptoms and signs on leaves and attributes of the fungus. The common name given to the disease was "necrotic sprinkling." This disease was found for the first time on barley in fields of Buenos Aires Province, Argentina, in 2001, with severities ranging from 60 to 100% (2). During the spring of 2012, the disease spread throughout most barley growing areas of the Pampean region, affecting almost all varieties of barley in the Buenos Aires, Entre Ríos, and Santa Fe provinces. The disease showed typical symptoms of small, brown spots on leaves, sheaths, and awns, and caused rapid loss of green leaf area and significant economic damage. The diagnosis of this disease is difficult by conventional techniques and has caused some confusion. In order to obtain appropriate information about the incidence of this pathogen in the most important barley growing region of Argentina, as well as to confirm its presence on seed, 39 seed samples containing 200 seeds each and eight leaf samples were analyzed using a real-time PCR diagnostic test (4). Thirty-five of the 37 seed samples had Rcc DNA levels above the minimum detection level (0.13 pg DNA). Ramularia has been described as a seedborne fungus previously (1) and seed infection could hasten the spread of the fungus to new geographically distinct areas. Moreover, leaf samples were microscopically assessed for conidophore presence and then ground for DNA extraction. Rcc DNA was detected by PCR in all eight leaf samples. To our knowledge, this is the first report about molecular detection of R. collo-cygni in barley seed of harvested samples from Argentina. Seeds infected/infested may also lead to new strains of the fungus arriving in barley fields and provide a source of inoculum for future epidemics (3). References: (1) N. D. Havis et al. FEMS Microbiol. Lett. 256:217, 2006. (2) M. Khier et al. Salpicado necrótico, nueva enfermedad de la cebada en Argentina causada por Ramularia collo-cygni. Page 47 in: Resúmenes XI Jornadas Fitosanitarias Argentinas, 26-29 June 2002, Río Cuarto, Córdoba, 2002. (3) P. Matusinsky et al. J. Plant Pathol. 3:679, 2011. (4) J. M. G. Taylor et al. Lett. Appl. Microbiol. 50:493, 2010.

Complete nucleotide sequence of an Argentinean isolate of sweet potato virus G.

Sweet potato virus G belongs to the largest plant virus genus Potyvirus. This virus was detected for the first time in Argentina and then sequenced using the method of next-generation pyrosequencing. The complete genome was found to be 10,798 nucleotides excluding the poly-A tail with a predicted genome organization typical for a member of the genus Potyvirus. This is the first report of the complete genomic sequence of a SPVG isolated from South America.

Evaluation of indigenous bacterial strains for biocontrol of the frogeye leaf spot of soya bean caused by Cercospora sojina.

AIMS: Assessment of biological control of Cercospora sojina, causal agent of frogeye leaf spot (FLS) of soya bean, using three indigenous bacterial strains, BNM297 (Pseudomonas fluorescens), BNM340 and BNM122 (Bacillus amyloliquefaciens). METHODS AND RESULTS: From cultures of each bacterial strain, cell suspensions and cell-free supernatants were obtained and assayed to determine their antifungal activity against C. sojina. Both mycelial growth and spore germination in vitro were more strongly inhibited by bacterial cell suspensions than by cell-free supernatants. The Bacillus strains BNM122 and BNM340 inhibited the fungal growth to a similar degree (I ≈ 52-53%), while cells from P. fluorescens BNM297 caused a lesser reduction (I ≈ 32-34%) in the fungus colony diameter. The foliar application of the two Bacillus strains on soya bean seedlings, under greenhouse conditions, significantly reduced the disease severity with respect to control soya bean seedlings and those sprayed with BNM297. This last bacterial strain was not effective in controlling FLS in vivo. CONCLUSIONS: Our data demonstrate that the application of antagonistic bacteria may be a promising and environmentally friendly alternative to control the FLS of soya bean. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of biological control of C. sojina by using native Bacillus strains.

First Report of Ascochyta rabiei Causing Ascochyta Blight of Chickpea in Argentina.

In November 2011, lesions similar to those reported for Ascochyta blight (1) were observed on Cicer arietinum L. (chickpea) plants growing in three commercial fields located at Río Primero and Río Segundo (Cordoba Province) and Lobería (Buenos Aires Province), Argentina. Disease incidence (percentage of plants affected) was 100% in all fields surveyed. Plants showed leaves, petioles, stems, and pods with brown lesions. Symptoms on leaves and pods were circular to oval (2 to 14 mm) while in the stems the lesions were elongated (2 to 30 mm). Seeds appeared small and shriveled with brown discoloration. Morphology of the fungi was examined on infected tissues. Numerous black pycnidia measuring 94.6 to 217.9 µm (145.9 ± 28.8 µm), arranged in concentric rings, were observed within of all the lesions. Conidia were predominantly aseptate, straight, hyaline with blunt ends, and measured 9.3 to 12.9 (11.3 ± 1.12) × 3.3 to 5.0 µm (4.2 ± 0.51). Morphological characteristics of the pathogen were similar to those described for Ascochyta rabiei (Pass.) Labrousse (teleomorph Didymella rabiei (Kovacheski) v. Arx (= Mycosphaerella rabiei Kovacheski)) (2). Fungus from infected leaf tissues was isolated on potato dextrose agar. Pathogenicity tests were conducted on seedlings of the susceptible cultivar by spraying leaves of each of 100 seedling plants with 10 ml of a conidial suspension (2 × 104 conidia/ml) of the isolated pathogen with a handheld atomizer. Plants were covered with plastic bags and placed in a growing chamber at 20 to 25°C for 3 days. The plastic bags were removed and the plants were maintained in high humidity at the same temperature. Noninoculated plants were used as controls. After 5 days, all inoculated plants showed typical symptoms. Foliar and stem lesions symptoms were similar to those originally observed in the field. Control plants remained healthy. Koch's postulates were fulfilled by isolating A. rabiei from inoculated plants. The colonies and the morphology of conidia were the same as those of the original isolates. To our knowledge, this is the first report of A. rabiei infecting chickpeas in Argentina. The outbreak of Ascochyta blight in Argentina is of concern because of its severity and the possibility that the pathogen was introduced on seed. This report underscores the need for further research on effective management programs for Ascochyta blight. References: (1) B. Bayaa and W. Chen. Compendium of Chickpea and Lentil Diseases and Pests The American Phytopathological Society, St. Paul, MN, 2011. (2) E. Punithalingam and P. Holliday. Page 337 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.

First Report of Races 11 and 12 of Cercospora sojina, the Causal Agent of Soybean Frogeye Leaf Spot, in Argentina.

During the growing seasons of 2008 to 2009 and 2009 to 2010, severe outbreaks of soybean (Glycine max (L.) Merr.) frogeye leaf spot, a disease caused by Cercospora sojina Hara, occurred in several areas in Argentina (1). Two surveys were conducted in soybean fields, one in 2008 that included the provinces of Buenos Aires, Córdoba, and Santa Fe, and another that was performed in 2009 in the same provinces plus three others: Entre Ríos, Santiago del Estero, and Tucumán. In both surveys, plants presented circular lesions with reddish brown-to-gray spots and bordered by typical, narrow, reddish purple margins (3). To promote sporulation and to enable identification of the causal agent, leaves of diseased plants were collected and placed in a moist chamber for 24 h with a 12-h light cycle at 25°C. Conidia were plated on potato dextrose agar medium amended with streptomycin and were incubated at 25°C and 12 h of fluorescent light. Isolated cultures sporulated in 10 days and, on the basis of their morphology, were identified as C. sojina. A total of 147 isolates were deposited at the Culture Collection of CEREMIC (Centro de Referencia de Micología). They produced one- to nine-septate hyaline, elongate to fusiform conidia that measured 54.9 ± 16.2 × 5.7 ± 1.0 µm. Six isolates of C. sojina, each representing a province, were inoculated on a set of 12 differential soybean cultivars: Lee, Davis, Hood, Richland, Lincoln, Kent, Tracy, S 100, Palmetto, Peking, CNS, and Blackhawk (2). Fifteen plants of each differential were sprayed at V3 growth stage with a suspension of 6 × 104 conidia/ml. The test was conducted twice in a complete randomized design with three replicates. Control plants were sprayed with sterile distilled water. After inoculation, plants were placed in a greenhouse bench humidity chamber at 26 to 28°C for 72 h. Disease was rated 14 days after inoculation; plants with numerous lesions were considered susceptible and each of the 15 plants was given a score of 1. Plants with small or no lesions were classified as resistant and given a score of 0. Control plants remained healthy. The pathogen was reisolated from symptomatic plants and morphological characteristics were consistent with C. sojina. Based on the response of the differentials to each isolate and on the race designations, the isolates from Buenos Aires, Córdoba, Santa Fe, and Tucumán belong to race 11, while those from Santiago del Estero and Entre Ríos province to race 12. The finding of these two races threatening soybean cultivars in Argentina may be indicative of additional races. Thus, the incorporation of multiple resistance genes may reduce the impact of the disease on soybean. To our knowledge, this is the first report of the identification of races of C. sojina in Argentina. References: (1) M. A. Carmona et al. Plant Dis. 93:966, 2009. (2) M. A. R. Mian et al. Crop Sci. 48:14, 2008. (3) D.V. Phillips. Page 20 in: Compendium of Soybean Diseases. 4th ed. APS Press, St. Paul, MN, 1999.

Complicación derivada del uso de Hem-O-Lok en la prostatectomía radical laparoscópica / Complications arising from the use of Hem-O-Lok in laparoscopic radical prostatectomy

Se presenta una rara complicación pos operatoria, la formación de pseu dodivertículo uretral, que se produce después de una prostatectomía radical laparoscópica con preservación de nervios, procedimiento llevado a cabo con la colocación de Hem-o-lok sobre los pedículos látero-prostáticos, en un paciente con cáncer de próstata clínicamente localizado. Por tanto, estos dispositivos deben utilizarse con precaución en la región de la anastomosis vesicouretral...

We present a rare postoperative complication, pseudodiverticulum urethral formation, occurring after a laparoscopic radical prostatectomy with nerve-sparing procedure carried out with the placement of Hem-o-lok c in the latero-prostatic pedicles, in a patient with clinically localized prostate cancer. As such, these devices should be used with caution in the region of the vesicourethral anastomosis...

First Report of Sexual Reproduction by the Soybean Sudden Death Syndrome Pathogen Fusarium tucumaniae in Nature.

Of the four fusaria that have been shown to cause soybean sudden death syndrome (SDS), field surveys indicate that Fusarium tucumaniae is the most important and genetically diverse SDS pathogen in Argentina. Although none of the SDS fusaria have been shown to produce perithecia in nature, a heterothallic sexual cycle has been demonstrated for F. tucumaniae via laboratory crosses. Herein we report on the discovery of perithecia of F. tucumaniae on soybean in Argentina. Ascospores derived from these perithecia gave rise to colonies that produced sporodochial conidia diagnostic of F. tucumaniae. Sporodochial conidia were longer and narrower than those produced by the other SDS fusaria; these conidia also possessed a diagnostic acuate apical cell and a distinctly foot-shaped basal cell. Sixteen strains derived from single ascospores subjected to a validated multilocus genotyping assay (MLGT) for SDS species determination, together with 16 conidial isolates from two sites where teleomorphs were collected, independently confirmed the morphological identification as F. tucumaniae. This study represents the first authentic report of sexual reproduction by a soybean SDS pathogen in nature.

Glomerular filtration is reduced by high tidal volume ventilation in an in vivo healthy rat model

Mechanical ventilation has been associated with organ failure in patients with acute respiratory distress syndrome. The present study examines the effects of tidal volume (V T) on renal function using two V T values (8 and 27 mL/kg) in anesthetized, paralyzed and mechanically ventilated male Wistar rats. Animals were randomized into two groups of 6 rats each: V T8 (V T, 8 mL/kg; 61.50 ± 0.92 breaths/min; positive end-expiratory pressure, 3.0 cmH2O; peak airway pressure (PAW), 11.8 ± 2.0 cmH2O), and V T27 (V T, 27 mL/kg; 33.60 ± 1.56 breaths/min; positive end-expiratory pressure, none, and PAW, 22.7 ± 4.0 cmH2O). Throughout the experiment, mean PAW remained comparable between the two groups (6.33 ± 0.21 vs 6.50 ± 0.22 cmH2O). For rats in the V T27 group, inulin clearance (mL·min-1·body weight-1) decreased acutely after 60 min of mechanical ventilation and even more significantly after 90 min, compared with baseline values (0.60 ± 0.05 and 0.45 ± 0.05 vs 0.95 ± 0.07; P < 0.001), although there were no differences between groups in mean arterial pressure or gasometric variables. In the V T8 group, inulin clearance at 120 min of mechanical ventilation remained unchanged in relation to baseline values (0.72 ± 0.03 vs 0.80 ± 0.05). The V T8 and V T27 groups did not differ in terms of serum thiobarbituric acid reactive substances (3.97 ± 0.27 vs 4.02 ± 0.45 nmol/mL) or endothelial nitric oxide synthase expression (94.25 ± 2.75 vs 96.25 ± 2.39 percent). Our results show that glomerular filtration is acutely affected by high tidal volume ventilation but do not provide information about the mechanism.

Glomerular filtration is reduced by high tidal volume ventilation in an in vivo healthy rat model.

Mechanical ventilation has been associated with organ failure in patients with acute respiratory distress syndrome. The present study examines the effects of tidal volume (V(T)) on renal function using two V T values (8 and 27 mL/kg) in anesthetized, paralyzed and mechanically ventilated male Wistar rats. Animals were randomized into two groups of 6 rats each: V (T)8 (V(T), 8 mL/kg; 61.50 +/- 0.92 breaths/min; positive end-expiratory pressure, 3.0 cmH(2)O; peak airway pressure (PAW), 11.8 +/- 2.0 cmH(2)O), and V T27 (V(T), 27 mL/kg; 33.60 +/- 1.56 breaths/min; positive end-expiratory pressure, none, and PAW, 22.7 +/- 4.0 cmH(2)O). Throughout the experiment, mean PAW remained comparable between the two groups (6.33 +/- 0.21 vs 6.50 +/- 0.22 cmH(2)O). For rats in the V(T)27 group, inulin clearance (mL.min(-1).body weight(-1)) decreased acutely after 60 min of mechanical ventilation and even more significantly after 90 min, compared with baseline values (0.60 +/- 0.05 and 0.45 +/- 0.05 vs 0.95 +/- 0.07; P < 0.001), although there were no differences between groups in mean arterial pressure or gasometric variables. In the V(T)8 group, inulin clearance at 120 min of mechanical ventilation remained unchanged in relation to baseline values (0.72 +/- 0.03 vs 0.80 +/- 0.05). The V(T)8 and V(T)27 groups did not differ in terms of serum thiobarbituric acid reactive substances (3.97 +/- 0.27 vs 4.02 +/- 0.45 nmol/mL) or endothelial nitric oxide synthase expression (94.25 +/- 2.75 vs 96.25 +/- 2.39%). Our results show that glomerular filtration is acutely affected by high tidal volume ventilation but do not provide information about the mechanism.

Alteration of the reproductive patterns in drosophila melanogaster by effects of high concentrations of boron on in vitro cultured medium / Alteración de los patrones reproductivos en drosophila melanogaster por efectos de altas concentraciones de boro en un medio de cultivo in vitro

The objective of this study was to evaluate the effects of boron (B) using as a biological model Drosophila malanogaster. Analizing specifically the responses over descendency to doses of 6,0 and 12 mg/L, comparing a control group which culture medium was prepared with water with boron concentrations of 0,6 mg/L, according to World Health Organization. The results show a significative alteration in the number of descendency from F1 to F3 and then a tendency to normalization in F4 and F5. Also a significant change in proportions between the males and females, with an acute effect on F1 and then a possible chronic effect from F2 to F5, increasing the proportion of females over males. This differences between genders are significant only until F4, on F5 these proportions are not significant. In F3 in doses of 12.0 mg/L of boron, it is observed a larger range of changes, altering the phenotypic expression, where the numbers of males which increase their size are significantly higher of those females who increase their size, 10 percent and 5,2 percent respectively. There is a tendency to normality in every pattern of study from the descendants of F4 and F5, above all the percentage of survival, possibly due action of steroid hormones of resistance to stress such as "ecdysone hormone".

El objetivo de este estudio fue evaluar el efecto del boro (B), usando como modelo biológico a Drosophila melanogaster. Específicamente analizar las respuestas sobre la descendencia a dosis de 6,0 y 12 mg/L y comparar con el grupo control cuya concentración de boro en el agua del medio de cultivo no supera los 0,6 mg/L, según los estándares de la Organización Mundial de la Salud. Los resultados muestran una alteración significativa en el número de la descendencia desde F1 a F3 y luego una tendencia a la normalización a partir de la F4 y F5. También hay un cambio significativo en las proporciones entre machos y hembras, con un efecto agudo en F1 y luego un posible efecto crónico desde F2 a F5, aumentando la proporción de hembras con respecto a los machos. Sin embargo estas diferencias entre sexos ya no son significativas solamente hasta F4. En F5 estas proporciones no son significativas. En F3 en dosis de 12 mg/L de boro, se observan los mayores cambios, alterando la expresión fenotípica, donde el número de machos que incrementan su tamaño, son significativamente más altos con respecto a las hembras que aumentan de tamaño. La tendencia a la normalidad en todos los patrones de estudio a partir de la descendencia F4 a F5, sobre todo en el porcentaje de sobreviva, posiblemente se deba a la acción de hormonas esteroidales de resistencia al estrés, tal como la hormona "Ecdysona".

Variable positive end-expiratory pressure can maintain oxygenation in experimental acute respiratory distress syndrome induced by oleic acid in dogs.

The use of positive end-expiratory pressure (PEEP) or lung recruitment maneuvers (RM) to improve oxygenation in acute respiratory distress syndrome (ARDS) is used but it may reduce cardiac output (CO). Intermittent PEEP may avoid these complications. Our objective was to determine if variable PEEP compared with constant PEEP is capable of maintaining arterial oxygenation and minimizing hemodynamic alterations with or without RM. Eighteen dogs with ARDS induced by oleic acid were randomized into three equal groups: group 1, low variable PEEP; group 2, high variable PEEP, and group 3, RM + high variable PEEP. All groups were submitted to constant PEEP, followed by variable PEEP (PEEP was increased from 5 to 10 cmH(2)O in group 1, and from 5 to 18 cmH(2)O in the other two groups). PaO(2) was higher in group 3 (356.2 +/- 65.4 mmHg) than in group 1 (92.7 +/- 29.7 mmHg) and group 2 (228.5 +/- 72.4 mmHg), P < 0.05. PaO(2) was maintained during variable PEEP except in group 2 (318.5 +/- 82.9 at constant PEEP to 228.5 +/- 72.4 at variable PEEP). There was a reduction in CO in group 3 after RM (3.9 +/- 1.1 before to 2.7 +/- 0.5 L*min(-1)*(m(2))(-1) after; P < 0.05), but there was not any difference between constant and variable PEEP periods (2.7 +/- 0.5 and 2.4 +/- 0.7 L*min(-1)*(m(2))(-1); P > 0.05. Variable PEEP is able to maintain PaO(2) when performed in combination with RM in dogs with ARDS. After RM, CO was reduced and there was no relevant difference between the variable and constant PEEP periods.

Variable positive end-expiratory pressure can maintain oxygenation in experimental acute respiratory distress syndrome induced by oleic acid in dogs

The use of positive end-expiratory pressure (PEEP) or lung recruitment maneuvers (RM) to improve oxygenation in acute respiratory distress syndrome (ARDS) is used but it may reduce cardiac output (CO). Intermittent PEEP may avoid these complications. Our objective was to determine if variable PEEP compared with constant PEEP is capable of maintaining arterial oxygenation and minimizing hemodynamic alterations with or without RM. Eighteen dogs with ARDS induced by oleic acid were randomized into three equal groups: group 1, low variable PEEP; group 2, high variable PEEP, and group 3, RM + high variable PEEP. All groups were submitted to constant PEEP, followed by variable PEEP (PEEP was increased from 5 to 10 cmH2O in group 1, and from 5 to 18 cmH2O in the other two groups). PaO2 was higher in group 3 (356.2 ± 65.4 mmHg) than in group 1 (92.7 ± 29.7 mmHg) and group 2 (228.5 ± 72.4 mmHg), P < 0.05. PaO2 was maintained during variable PEEP except in group 2 (318.5 ± 82.9 at constant PEEP to 228.5 ± 72.4 at variable PEEP). There was a reduction in CO in group 3 after RM (3.9 ± 1.1 before to 2.7 ± 0.5 L·min-1·(m2)-1 after; P < 0.05), but there was not any difference between constant and variable PEEP periods (2.7 ± 0.5 and 2.4 ± 0.7 L·min-1·(m2)-1; P > 0.05. Variable PEEP is able to maintain PaO2 when performed in combination with RM in dogs with ARDS. After RM, CO was reduced and there was no relevant difference between the variable and constant PEEP periods.

Oral yeast carriage in HIV-infected and non-infected populations in Rosario, Argentina.

The objectives of the present study were: (i) to assess the frequency of oral colonisation by Candida species in HIV-positive patients and to compare it with a population of HIV-negative individuals, (ii) to determine the prevalence of C. dubliniensis in both populations and (iii) to determine the susceptibility of C. dubliniensis and other Candida species isolated from HIV-positive patients to the most commonly used antifungal agents. Oral samples were obtained from 101 HIV-positive and 108 HIV-negative subjects. For yeast identification, we used morphology in cornmeal agar, the API 20C Aux, growth at 45 degrees C, d-xylose assimilation, morphology in sunflower seed agar and PCR. The frequency of isolation of Candida in HIV-positive patients was: C. albicans, 60.7%; C. dubliniensis, 20.2%; C. glabrata, 5.6%; C. krusei, 5.6%; C. tropicalis, 4.5%; others, <5%. The frequency of isolation of Candida in HIV-negative patients was: C. albicans, 73.9%; C. tropicalis, 15.5%; C. dubliniensis, 2.1%; C. glabrata, 2.1%; C. parapsilosis, 2.1%; others, <5%. The oral colonisation by yeast in the HIV-positive patients was higher than that in the HIV-negative subjects. The susceptibilities of 42 Candida isolates to three antifungal agents were determined. All isolates of C. dubliniensis were susceptible to fluconazole, although several individuals had been previously treated with this drug. Out of the 42 Candida isolates, 10 presented resistance to fluconazole and 10 to itraconazole. The presence of Candida species, resistant to commonly used antifungal agents, represents a potential risk in immunocompromised patients.

Severe Outbreaks of Soybean Frogeye Leaf Spot Caused by Cercospora sojina in the Pampean Region, Argentina.

Frogeye leaf spot of soybean (Glycine max (L.) Merr.) caused by Cercospora sojina Hara was reported to be severe from 1998 to 1999 in northwest Argentina (2). Although the disease was detected at low prevalence (5 to 25%), incidence, and severity in the Pampean Region from 2005 to 2008, no severe outbreaks have been recorded in the provinces of Córdoba, Santa Fe, and Buenos Aires. During the 2008-2009 growing season, disease spread rapidly throughout most soybean-growing areas of the Pampean Region. Disease was observed on almost all varieties of maturity group (MG) III, IV, and V. Symptoms on leaves were circular, reddish brown-to-gray spots (1 to 6 mm) and bordered by typical, narrow, reddish purple margins. Morphology of the fungi was examined on infected tissues. Conidiophores were light-to-dark brown, fasciculate, geniculate, and measured 110 to 203 µm long. Conidia were 1 to 9 septate, hyaline, elongate to fusiform, and measured 26 to 111 (47.3 ± 14.7) × 5.2 to 7.4 µm (6.1 ± 0.7). Pathogenicity tests were conducted on seedlings of a susceptible cultivar by spraying leaves of each of 80 plants at the V3 growth stage with 18 ml of a conidial suspension (3 × 104 conidia/ml) with a hand-held atomizer. Plants were covered with plastic bags and placed in a greenhouse at 28 to 30°C for 48 h. The plastic bags were removed and plants were maintained in high humidity at the same temperature. The same number of noninoculated plants was used as controls. After 10 to 12 days, all inoculated plants showed typical symptoms. Koch's postulates were fulfilled by isolating C. sojina from inoculated plants. Control plants remained healthy. Foliar lesions and morphological characteristics of the pathogen were consistent with C. sojina (1). Disease assessments were made for the middle and upper canopy from 15 arbitrarily collected plants. Soybean plants were in growth stages between R3 and R5 during the survey. Incidence (percentage of plants affected) and severity (percentage of leaf area affected with lesions) were visually estimated from each of the 30 soybean-production fields located in Monte Cristo, Alta Gracia, Jesús María, W. Escalante, Monte Buey, (10 fields, Córdoba Province), Venado Tuerto, Villa Cañás, Cristophersen, María Teresa, (12 fields, Santa Fe Province), Pergamino, Rojas, and Salto (8 fields, Buenos Aires Province). Incidence was 100% in all fields from Córdoba and Santa Fe. Incidence in Buenos Aires was 0 to 100%. Highest severity levels were quantified from fields in Córdoba (severity of 30 to 60%). Lesions also developed on stems and pods. In samples from Buenos Aires, severity levels were ≤10% in the eight soybean fields. Number of lesions per leaflet was recorded from central leaflets in samples from Monte Cristo, Alta Gracia, Venado Tuerto, and María Teresa with 20 to 55 typical lesions per leaflet. Since the disease was always more important in northwest Argentina, genetic resistance is more commonly available in varieties of MG VII to VIII, so most of the varieties of MG III, IV, and V frequently planted in Pampean Region are susceptible. This fact in combination with rainfall, warm temperatures, and high relative humidity in no-till fields during this summer have encouraged the severe outbreak of frogeye leaf spot, especially in the province of Córdoba and in some regions of Santa Fe. References: (1) D. V. Phillips. Page 20 in: Compendium of Soybean Diseases. 4th ed. The American Phytopathological Society. St. Paul, MN, 1999. (2) D. L. Ploper et al. Plant Dis. 85:801, 2001.

Recent Outbreak of Soybean Sudden Death Syndrome Caused by Fusarium virguliforme and F. tucumaniae in Argentina.

Sudden death syndrome (SDS) of soybean was detected initially in Argentina during 1991-1992 in the Pampas Region and 1992-1993 in the Northwest Region. The first report of the fulfillment of Koch's postulates of SDS caused by Fusarium solani f. sp. glycines in Argentina was published in 2003 (3). Subsequently, analyses have shown that F. solani f. sp. glycines represents several morphologically and phylogenetically distinct species, including F. tucumaniae in Argentina and F. virguliforme in the United States (1). Isolations were made from plants that exhibited typical SDS symptoms (interveinal foliar chlorosis and necrosis leading to defoliation of the leaflets but not the petioles) from fields in Santa Fe and Buenos Aires provinces in 2001, 2002, and 2003. To determine which species are responsible for SDS in Argentina, cultures of eight slow growing isolates that developed bluish pigmentation and produced abundant macroconidia in sporodochia on potato dextrose agar were subjected to morphological and molecular phylogenetic analyses and pathogenicity tests. Morphological analyses demonstrated that three of the isolates were F. virguliforme and five were F. tucumaniae. Isolates of F. tucumaniae produced long and narrow sporodochial conidia while F. virguliforme produced diagnostic comma-shaped conidia. Molecular phylogenetic analyses of DNA sequences from multiple loci confirmed morphology-based identifications and showed that the soybean SDS pathogen in the United States, F. virguliforme, was also present in Argentina. To our knowledge, this is the first report of F. virguliforme in Argentina and of this pathogen outside the United States. Five isolates of F. tucumaniae and three isolates of F. virguliforme were used for pathogenicity tests. F. virguliforme isolate 171 provided by J. Rupe (University of Arkansas, Fayetteville) was used as a positive control. Soybean cultivars Ripley, RA 702, Pioneer 9492RR, Spencer, and A-6445RG were inoculated with each of the isolates tested in a greenhouse assay using soil infestation and toothpick methods (2). All eight isolates produced typical foliar SDS symptoms 15 to 25 days after inoculation. Severity of foliar symptoms averaged 3.3 for F. virguliforme, 2.6 for F. tucumaniae, and 3.3 for the positive control using a disease severity scale in which 1 = no symptoms and 5 = severely infected or dead plants. Under these conditions, F. virguliforme appeared to be more virulent than F tucumaniae. Noninoculated plants remained symptomless. Koch's postulates were confirmed with soybean cultivars RA 702 and A6445RG. Isolates recovered from symptomatic plants inoculated by the soil infestation and toothpick methods were identical to those used to inoculate the plant. Strains were recovered at frequencies of 100 and 60% from plants inoculated by the toothpick and soil infestation methods, respectively. To our knowledge, this is the first report of the fulfillment of Koch's postulates for F. tucumaniae and F. virguliforme in Argentina. References: (1) T. Aoki et al. Mycologia 95:660, 2003. (2) K. W. Roy et al. Plant Dis. 81:1100, 1997 (3) M. Scandiani et al. Plant Dis. 87:447, 2003.