Effect of hypoxia and nitrate supplementation on different high-intensity interval-training sessions.

PURPOSE: To test the hypothesis that interval-training (IHT) would be impaired by hypoxia to a larger extent than repeated-sprint training (RSH) and that dietary nitrate (NO3-) would mitigate the detrimental effect of hypoxia to a larger extent during IHT than RSH. METHODS: Thirty endurance-trained male participants performed IHT (6 × 1 min at 90%∆ with 1 min active recovery) and RSH (2 sets of 6 × 10 s "all-out" efforts with 20 s active recovery) on a cycle ergometer, allocated in one of three groups: normobaric hypoxia (~ 13% FiO2) + NO3- - HNO, n = 10; normobaric hypoxia + placebo - HPL, n = 10; normoxia (20.9% FiO2) + placebo - CON, n = 10. Submaximal oxygen uptake ([Formula: see text]O2), time spent above 90% of maximal [Formula: see text]O2 (≥ 90 [Formula: see text]O2max) and heart rate (≥ 90 HRmax) were compared between IHT and RSH sessions and groups. Additionally, mean power output (MPO), decrement score and % of power associated with [Formula: see text]O2max (%p[Formula: see text]O2max) in RSH sessions were analyzed. RESULTS: [Formula: see text]O2 at sub-maximal intensities did not differ between training protocols and groups (~ 27 ml kg-1 min-1). ≥ 90 HRmax was significantly higher in IHT compared to RSH session (39 ± 8 vs. 30 ± 8%, p = 0.03) but only in HNO group. MPO (range 360-490 W) and decrement score (10-13%) were similar between groups although %p[Formula: see text]O2max was significantly higher (p = 0.04) in CON (166 ± 16 W) compared with both HPL (147 ± 15 W) and HNO (144 ± 10 W) groups. CONCLUSION: IHT responses were neither more impaired by hypoxia than RSH ones. Moreover, dietary NO3- supplementation impacted equally IHT and RSH training responses' differences between hypoxia and normoxia.

Identificação de Mycobacterium bovis em carcaças de bovinos abatidos no estado da Bahia, Brasil, por métodos bacteriológico e molecular / Identification of Mycobacterium bovis in carcasses of cattle slaughtered in Bahia state, Brazil by bacteriological and molecular methods

O objetivo do presente trabalho foi utilizar métodos bacteriológicos e moleculares para a identificação do Mycobacterium bovis em lesões observadas em carcaças de bovinos durante a inspeção post mortem de rotina em matadouros-frigoríficos com serviço de inspeção oficial. Foram acompanhados o abate e a inspeção de 825.394 bovinos, sadios, ao exame ante mortem pelo serviço de inspeção oficial em 10 matadouros-frigoríficos do estado da Bahia, entre abril de 2009 e abril de 2012. Cento e oitenta bovinos apresentaram lesões sugestivas de tuberculose e outras linfadenites, as quais foram avaliadas quanto à presença de Mycobacterium bovis por exame bacteriológico e pela PCR multiplex. A maioria das lesões estava localizada em linfonodos do trato respiratório e 71% eram provenientes de bovinos machos com até 32 meses de idade. No isolamento bacteriano, 13,9% (25/180) das amostras apresentavam colônias pequenas, de superfície granular e de coloração creme-amareladas, em meio de cultura Stonebrink-Leslie, e o crescimento médio foi de 34 dias. Todos os esfregaços dos isolados evidenciaram BAAR, e, pela PCR multiplex, 56% (14/25) dos isolados foram identificados como M. bovis. A associação entre exame post mortem, bacteriológico e PCR multiplex permitiu a identificação do agente de forma rápida e em regiões com status sanitário de baixa prevalência, demonstrando ser importante para a detecção dos focos de tuberculose bovina e o auxílio nos programas de controle e erradicação da tuberculose...

The aim of the present study was to perform bacteriological and molecular methods for identification of Mycobacterium bovis in lesions derived from bovine carcasses detected during routine post-mortem examination in officially inspected slaughterhouses. We checked the slaughter and inspection of 825,394 bovines, health upon ante-mortem examination, by the official service in 10 slaughterhouses of Bahia state from April, 2009 to April 2012. Lesions suggestive of tuberculosis were collected from 180 bovines and further evaluated by bacteriology and multiplex PCR. The majority of lesions were located in the respiratory tract lymph nodes and 71% were from male bovines up to 32 months old. 13.9% of samples presented small, granular and creamy-yellowish colonies after being cultured in Stonebrink-Leslie with an average growth time of 34 days. All smears from the isolated samples were Acid Fast Bacilli (AFB) and among them 56% were identified by mPCR as M. bovis. Thus, the association between post-mortem examination, culture and multiplex PCR allowed the bacillus identification in a reduced time and in regions of low prevalence, pointing out its importance for bovine tuberculosis detection and as a supportive tool for the tuberculosis control and eradication program...

IL-13: a marker of chromium contact allergy.

BACKGROUND: Allergic contact dermatitis is a frequent, often disabling disease caused by countless substances. Patch testing remains the gold standard test to identify the causative agent; however, it is subjective, time-consuming and not completely safe. Alternative methods were tried, but significant success has only been achieved with nickel. OBJECTIVE: Develop an alternative or complementary allergic contact dermatitis diagnostic test. METHODS: We compared the lymphocyte proliferative rate and cytokine production (IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-17 and RANTES) between 18 chromium allergic patients and 19 controls. RESULTS: The lymphocyte proliferation test and some of the cytokines tested (IFN-γ, IL-2, IL-5, IL-12 and IL-13) were able to discriminate allergic patients. However, striking results were only achieved using IL-13, leading to an accuracy of about 90%. CONCLUSIONS: If further studies confirm the data found, IL-13 could be used as an alternative or complementary test to detect chromium contact allergy whereas lymphocyte proliferation test, IFN-γ, IL-2, IL-5 and IL-12 detections may serve as additional diagnostic tests.

Diagnosing oral lichenoid contact reaction: clinical judgment versus skin-patch test.

AIM: Objective of this study was to compare the skin-patch test with the clinical diagnosis of oral lichenoid contact reaction (OLCR) as indicators for amalgam replacement. METHODS: Of 53 patients (38 female and 15 male; mean age 48.7) with oral lichen planus (OLP), 26 were identified as having OLCR, and clinically graded according to the proximity of their lesions with amalgam fillings: class I (weak association), class II (moderate association), and class III (strong association). All OLCR patients were skin-patch tested for both standard (Brazilian) and specific allergens (TROLAB, Germany). Patients were considered skin-patch positive only if they developed positive skin reactions for thimerosal and/or amalgam components. Amalgam replacement was indicated in all class II and III patients. For class-I patients, amalgam replacement was indicated only if they were skin-patch test positive. Readings for the skin-patch test were made at 48h and 96h. RESULTS: Of the 26 patients with OLCR, two missed the follow-up and were excluded, leaving 24 cases. Of these, four were class-I, and all were negative for the skin-patch test. Twelve were class-II, of whom seven were skin-patch positive. Eight were class-III, of whom six were skin-patch positive. Following amalgam replacement in the 12 class-II patients, six showed improvement and six had complete resolution, while in the eight class-III patients, two showed improvement and six a complete resolution. CONCLUSION: Clinical diagnosis of OLCR lesions is a more reliable indicator for the question of amalgam replacement than is the skin-patch test.

Low sampling rates bias outcomes from the Wingate test.

The purpose of this work was to apply a simple method for acquisition of power output (PO) during the Wingate Anaerobic Test (WAnT) at a high sampling rate ( S(R)) and to compare the effect of lower S(R) on the measurements extracted from the PO. 26 male subjects underwent 2 WAnTs on a cycle ergometer. The reference PO was calculated at 30 Hz as a function of the linear velocity, the moment of inertia and the frictional load. The PO was sampled at 0.2, 0.5, 1, 2 and 5 Hz. Both the peak (16.03±2.22 W·kg (-1)) and mean PO (10.34±1.01 W·kg (-1)) presented lower relative values when the S(R) was lower. Peak PO was attenuated by 0.29-42.07% for decreasing sampling rates, resulting in different values for 0.2 and 1 Hz ( P<0.001). When the S(R) was 0.2 Hz, the time to peak was delayed by 53.81% ( P<0.001) and the fatigue index was attenuated by 22.12% ( P<0.001). In conclusion, due to the differences achieved here and the fact that the peak flywheel frequency is around 2.3 Hz, we strongly recommend that the PO be sampled at 5 Hz instead of 0.2 Hz in order to avoid biased errors and misunderstandings of the WAnT results.

Oxygen uptake, heart rate and energy expenditure during slideboard routines at different cadence.

AIM: Little is known about the physiological response during slideboard exercise (SE). The aim of the present study was to analyse the oxygen uptake (V.O2), the heart rate (HR) and the energy expenditure (EE) during a typical slideboard exercise session and investigate differences on these variables when performing the same choreography at two different cadences (130 e 145 beats per minute - bpm). METHODS: The sample comprised 13 female university students (21,77+/-0,97 years), apparently healthy and physically active, with past training in SE and mastering the technical levels 1 and 2. The subjects performed randomly exercise sessions at 130 bpm and 145 bpm. The ventilatory response was measured by an open air circuit system (COSMED K4b2, Rome, Italy) and HR was measured by a portable monitor (Polar Wireless Double Electrode, Kempele, Finland). HR and V.O2, during SE at 130 bpm, were 179.88+/-834 bpm and 37.95+/-3.71 mL/kg/min respectively. At 145 bpm SE mean values were 182.08+/-9.58 bpm and 39.67+/-3.82 mL/kg/min respectively. EE during 130 bpm exercise was 10.60+/-1.69 kcal/min and at 145 bpm was 10.90+/-1.36 kcal/min. No differences were found between 130 and 145 bpm in none of the variables. We conclude that slideboard exercise cardio respiratory response does not seem affected by the rhythm of execution. Moreover the EE associated with this type of exercise is above the literature reports for other types of group aerobic exercises.

Examining the accumulated oxygen deficit method in front crawl swimming.

The present study investigated the Accumulated Oxygen Deficit (AOD) method in front crawl swimming with the aims to assess the robustness of the oxygen uptake/swimming velocity regression line and to quantify the precision of the AOD. Twenty-nine male swimmers performed two swimming tests in different days, with a 24 h recovery between tests: a graded test and an all-out test. The all-out test was performed either in 100 m (n=11), 200 m (n=13) or 400 m (n=5). Through all testing expired gases were collected breath by breath and analysed with a K4b2 Gas Analyser (Cosmed, Rome, Italy) connected to an AquaTrainer Valve (Cosmed, Rome, Italy). The error of oxygen uptake/swimming velocity regression lines was approximately 4-5 ml x kg (-1) x min (-1)) and the regressions allowed an extrapolation of the energy cost to higher intensities with a standard error of prediction of approximately 3-4 ml x kg (-1) x min (-1). However, the data variability was considerable (95% confidence intervals of the linear extrapolation larger than 13 ml x kg (-1) x min (-1)). The AOD imprecision varied among the three distance events from approximately 3-13 ml x kg (-1). These absolute errors are small, considering the time that subjects took to cover the three distances, but relative to the AOD values that were estimated they can be considered high, especially in the 400 m bout.

Lymphocyte proliferation testing in chromium allergic contact dermatitis.

BACKGROUND: Lymphocyte proliferation testing (LPT) has some advantages over patch testing to diagnose allergic contact dermatitis. It is harmless, objective and can be used in clinical situations where patch testing is not recommended. Unfortunately, significant success has only been achieved with nickel. There are few studies on chromium LPT and they were performed with different methods, leading to inconsistent results. METHODS: To determine the best parameters for chromium LPT, we tested 20 patients with allergic contact dermatitis to the metal and 20 controls, using various protocols. RESULTS: The best sensitivity and specificity ratios were achieved with 6-day cultures stimulated with a range from 7.5 x 10(-4) to 5 x 10(-3) mol/L of nonfiltered chromium chloride solutions. The sensitivity, specificity and accuracy values found within this range were 65%, 95% and 80%, respectively. CONCLUSION: Further investigation is necessary to achieve better sensitivity values.

[A study on the quality of life in ischaemic vascular accidents and its relation to physical activity]. / Estudio de la calidad de vida en el accidente vascular isquémico y su relación con la actividad física.

INTRODUCTION: Cerebrovascular accidents (CVA) are the third most common cause of death and are the main cause of permanent disability in the western world, where they also rank first as regards the loss of years of disability-adapted independent life. Ischaemic CVAs tend to present irreversible sequelae, which reduces the patient's quality of life. AIM: To analyse the effect of a series of exercises carried out in water on the quality of life of patients who have had an ischaemic CVA. SUBJECTS AND METHODS: Two groups were studied: an experimental group made up of 15 subjects aged 50.3 +/- 9.1 years, and a control group consisting of 13 subjects aged 52.5 +/- 7.7 years. The experimental group followed a 12-week programme of aquatic physical exercises. The two groups were evaluated in a pre- and post-treatment and then results from both groups were compared. Data were collected by administering a generic health-related quality of life survey (SF-36). RESULTS: Significant differences were found between the pre- and post-treatment in the experimental group. In the between-groups evaluation, significant differences were recorded with regard to functional capacity, physical aspects, pain, general state of health, vitality, social aspects and mental health. CONCLUSIONS: Doing physical exercises in water tends to improve motor behaviour, with a greater degree of independence, significant improvements in functional capacity and other aspects linked to physical aptitude. As a result, the level of quality of life of individuals affected by ischaemic CVA is enhanced.

Estudio de la calidad de vida en el accidente vascular isquémico y su relación con la actividad física / A study on the quality of life in ischaemic vascular accidents and its relation to physical activity

El accidente vascular cerebral (AVC) ocupa la tercera posición en la causa de muertes y constituyela principal causa de incapacidad permanente en los países occidentales, ocupando el primer lugar en la pérdida de años de vida independiente adaptada a la incapacidad. El AVC isquémico tiende a presentar secuelas irreversibles, lo que provocapérdidas en cuanto a la calidad de vida. Objetivo. Analizar el efecto de un programa de ejercicios acuáticos sobre la calidad de vida de portadores del AVC isquémico. Sujetos y métodos. Se estudiaron dos grupos, un grupo experimental formado por 15 sujetos con una edad de 50,3 ± 9,1 años, y un grupo control con 13 sujetos de edad 52,5 ± 7,7 años. El grupo experimentalfue sometido a 12 semanas de ejercicios acuáticos. Se evaluaron los dos grupos en un pre y postratamiento y, posteriormente, se realizó la comparación entre los grupos. Para efectuar la recogida de datos se empleó un cuestionario genérico de calidad de vida en salud (SF-36). Resultados. Se encontraron diferencias significativas entre el pre y el postratamiento delgrupo experimental. En la evaluación entre grupos, se registraron diferencias significativas en la capacidad funcional, aspectos físicos, dolor, estado general de salud, vitalidad, aspectos sociales y salud mental. Conclusión. La práctica de actividadesfísicas acuáticas tiende a proporcionar una mejora en el comportamiento motor, con una mayor independencia, mejoras significativas en la capacidad funcional y otros aspectos ligados a la aptitud física, lo que aporta así una mejoría en el nivel de calidad de vida de personas afectadas por el AVC isquémico

Cerebrovascular accidents (CVA) are the third most common cause of death and are the main causeof permanent disability in the western world, where they also rank first as regards the loss of years of disability-adapted independent life. Ischaemic CVAs tend to present irreversible sequelae, which reduces the patient’s quality of life. Aim. To analyse the effect of a series of exercises carried out in water on the quality of life of patients who have had an ischaemic CVA. Subjects and methods. Two groups were studied: an experimental group made up of 15 subjects aged 50.3 ± 9.1 years, and a control group consisting of 13 subjects aged 52.5 ± 7.7 years. The experimental group followed a 12-week programme of aquatic physical exercises. The two groups were evaluated in a pre- and post-treatment and then results from both groups were compared. Data were collected by administering a generic health-related quality of life survey (SF-36). Results. Significantdifferences were found between the pre- and post-treatment in the experimental group. In the between-groups evaluation, significant differences were recorded with regard to functional capacity, physical aspects, pain, general state of health, vitality, social aspects and mental health. Conclusions. Doing physical exercises in water tends to improve motor behaviour,with a greater degree of independence, significant improvements in functional capacity and other aspects linked to physical aptitude. As a result, the level of quality of life of individuals affected by ischaemic CVA is enhanced

Slow component of VO(2) during level and uphill treadmill running: relationship to aerobic fitness in endurance runners.

AIM: The aim of this study was to compare the oxygen uptake (VO(2)) slow component (SC) during level and uphill running in endurance runners, and to identify associations between the SC and the following aerobic fitness indicators: peak VO(2), running speed associated with the peak VO(2) (Vpeak), running speed at the lactic threshold and the VO(2) fraction elicited at the lactic threshold. METHODS: Fourteen male endurance-trained runners underwent several 6-min bouts of level (LTR) and 10.5% uphill treadmill running. VO(2) SC was calculated as the difference between mean VO(2) during the 6th and the 3rd minutes. RESULTS: The highest mean values for the SC were 181.9+/-240.2 mL x min(-1) for level running at approximately 94% peak VO(2)2 and 105.4+/-154.6 mL x min(-1) for uphill running at approximately 90% peak VO(2). The SC observed during the last bout of the LTR correlated with peak VO(2) and with Vpeak (-0.71 and -0.76, P<0.05, respectively). CONCLUSION: The results show that for endurance-trained runners the magnitude of the SC is not affected by the treadmill gradient and that within a homogeneous sample of endurance-trained runners the SC does not correlate with indicators of aerobic fitness.

Burkholderia silvatlantica sp. nov., a diazotrophic bacterium associated with sugar cane and maize.

In a previous study, nitrogen-fixing isolates were recovered from the rhizosphere of maize and from surface-sterilized leaves of sugar cane cultivated in Rio de Janeiro, Brazil. On the basis of 16S rRNA gene sequence similarities, these isolates were identified as belonging to the genus Burkholderia, and whole-cell-protein profiles demonstrated that they are closely related to each other. In the present study, novel isolates were recovered from the roots of different sugar-cane varieties cultivated in diverse geographical regions of Brazil. Twenty-one nitrogen-fixing isolates were analysed using polyphasic taxonomy criteria, including DNA-DNA relatedness, 16S rRNA gene sequence similarities, fatty acid profiles, whole-cell-protein patterns and multilocus enzyme electrophoresis profiles, as well as morphological, physiological and biochemical characterization. The analysis confirmed that these isolates belong to a novel species within the genus Burkholderia, for which the name Burkholderia silvatlantica sp. nov. is proposed. The type strain, SRMrh-20(T) (=LMG 23149(T)=ATCC BAA-1244(T)), was isolated from the rhizosphere of maize var. Avantis A2345 cultivated in Seropédica, Rio de Janeiro.

Diazotrophic burkholderia species associated with field-grown maize and sugarcane.

Until recently, diazotrophy was known in only one of the 30 formally described species of Burkholderia. Novel N(2)-fixing plant-associated Burkholderia species such as B. unamae, B. tropica, and B. xenovorans have been described, but their environmental distribution is scarcely known. In the present study, the occurrence of N(2)-fixing Burkholderia species associated with different varieties of sugarcane and maize growing in regions of Mexico and Brazil was analyzed. Only 111 out of more than 900 isolates recovered had N(2)-fixing ability as demonstrated by the acetylene reduction assay. All 111 isolates also yielded a PCR product with primers targeting the nifH gene, which encodes a key enzyme in the process of nitrogen fixation. These 111 isolates were confirmed as belonging to the genus Burkholderia by using a new 16S rRNA-specific primer pair for diazotrophic species (except B. vietnamiensis) and closely related nondiazotrophic Burkholderia. In Mexico, many isolates of B. unamae (predominantly associated with sugarcane) and B. tropica (more often associated with maize) were recovered. However, in Brazil B. tropica was not identified among the isolates analyzed, and only a few B. unamae isolates were recovered from one sugarcane variety. Most Brazilian diazotrophic Burkholderia isolates (associated with both sugarcane and maize plants) belonged to a novel species, as revealed by amplified 16S rRNA gene restriction profiles, 16S rRNA gene sequencing, and protein electrophoresis. In addition, transmissibility factors such as the cblA and esmR genes, identified among clinical and environmental isolates of opportunistic pathogens of B. cenocepacia and other species of the B. cepacia complex, were not detected in any of the plant-associated diazotrophic Burkholderia isolates analyzed.

Burkholderia tropica sp. nov., a novel nitrogen-fixing, plant-associated bacterium.

In an ecological survey of nitrogen-fixing bacteria isolated from the rhizosphere and as endophytes of sugarcane, maize and teosinte plants in Brazil, Mexico and South Africa, a new phylogenetically homogeneous group of N(2)-fixing bacteria was identified within the genus Burkholderia. This polyphasic taxonomic study included microscopic and colony morphology, API 20NE tests and growth on different culture media at different pH and temperatures, as well as carbon source assimilation tests and whole-cell protein pattern analysis. Analysis of 16S rRNA gene sequences showed 99.2-99.9 % similarity within the novel species and 97.2 % similarity to the closest related species, Burkholderia sacchari. The novel species was composed of four distinct amplified 16S rDNA restriction analysis groups. The DNA-DNA reassociation values within the novel species were greater than 70 % and less than 42 % for the closest related species, B. sacchari. Based on these results and on many phenotypic characteristics, a novel N(2)-fixing species is proposed for the genus Burkholderia, Burkholderia tropica sp. nov., with the type strain Ppe8(T) (=ATCC BAA-831(T)=LMG 22274(T)=DSM 15359(T)). B. tropica was isolated from plants grown in geographical regions with climates ranging from temperate subhumid to hot humid.

Further observations on the interaction between sugar cane and Gluconacetobacter diazotrophicus under laboratory and greenhouse conditions.

Sugar cane (Saccharum spp.) variety SP 70-1143 was inoculated with Gluconacetobacter diazotrophicus strain PAL5 (ATCC 49037) in two experiments. In experiment 1 the bacteria were inoculated into a modified, low sucrose MS medium within which micropropagated plantlets were rooted. After 10 d there was extensive anatomical evidence of endophytic colonization by G. diazotrophicus, particularly in lower stems, where high numbers of bacteria were visible within some of the xylem vessels. The identity of the bacteria was confirmed by immunogold labelling with an antibody raised against G. diazotrophicus. On the lower stems there were breaks caused by the separation of the plantlets into individuals, and at these 'wounds' bacteria were seen colonizing the xylem and intercellular spaces. Bacteria were also occasionally seen entering leaves via damaged stomata, and subsequently colonizing sub-stomatal cavities and intercellular spaces. A localized host defence response in the form of fibrillar material surrounding the bacteria was associated with both the stem and leaf invasion. In experiment 2, stems of 5-week-old greenhouse-grown plants were inoculated by injection with a suspension of G. diazotrophicus containing 10(8) bacteria ml(-1). No hypersensitive response (HR) was observed, and no symptoms were visible on the leaves and stems for the duration of the experiment (7 d). Close to the point of inoculation, G. diazotrophicus cells were observed within the protoxylem and the xylem parenchyma, where they were surrounded by fibrillar material that stained light-green with toluidine blue. In leaf samples taken up to 4 cm from the inoculation points, G. diazotrophicus cells were mainly found within the metaxylem, where they were surrounded by a light green-staining material. The bacteria were growing in relatively low numbers adjacent to the xylem cell walls, and they were separated from the host-derived material by electron-transparent 'haloes' that contained material that reacted with the G. diazotrophicus antibody.

Herbaspirillum frisingense sp. nov., a new nitrogen-fixing bacterial species that occurs in C4-fibre plants.

The enrichment of nitrogen-fixing bacteria from the C4-fibre plants, Spartina pectinata, Miscanthus sinensis, Miscanthus sacchariflorus and Pennisetum purpureum, with nitrogen-free semi-solid media led to the isolation of Herbaspirillum-like strains among other diazotrophic bacteria. On the basis of physiological properties, phylogenetic analysis comparing 16S rDNA sequences and DNA-DNA hybridization experiments of chromosomal DNA the new isolates could be grouped together in a new species with the proposed name Herbaspirillum frisingense sp. nov. Morphological characteristics, such as cell size and shape, colony appearance, motility and flagellation are largely identical to the known species Herbaspirillum rubrisubalbicans and Herbaspirillum seropedicae. On the basis of utilization of adipate (-), N-acetyl-D-glucosamine (+), meso-erythritol (-), L-rhamnose (-) and meso-inositol (-) Herbaspirillum frisingense sp. nov. can be distinguished from other known Herbaspirillum spp. Nitrogen-fixing capability was examined by PCR amplification of the nifD gene and an acetylene reduction assay, and was found with all isolates tested. 16S rDNA sequence similarity to the other Herbaspirillum spp. is 98.5-99.1%. In genomic DNA-DNA hybridization experiments Herbaspirillum frisingense sp. nov. forms a homogeneous group with 70-100+/-10% similarity, clearly distinct from Herbaspirillum seropedicae and Herbaspirillum rubrisubalbicans with 1-34% similarity. 16S rRNA-targeted oligonucleotide probes, specific for the whole genus Herbaspirillum and for three Herbaspirillum species were designed and are suitable for fluorescence in situ hybridization. The DNA G+C content of Herbaspirillum frisingense sp. nov. is 63+/-2 mol%, in agreement with the values of 61-65% for the genus. PCR fingerprinting exhibits a consistent pattern for groups of strains isolated from the same plant, suggesting a low genomic diversity among bacteria inhabiting C4-gramineous plant tissues. Low genetic DNA diversity seems to be common between probable endophytic bacterial isolates of the same taxon. The type strain of Herbaspirillum frisingense sp. nov. is GSF30T (= DSM 13128T).

UVB-induced acantholysis in endemic Pemphigus foliaceus (Fogo selvagem) and Pemphigus vulgaris.

BACKGROUND: The autoantibody-mediated disease in fogo selvagem (FS) is aggravated by sunlight exposure. OBJECTIVE: The aim of this study was to test whether UVB exposure of uninvolved skin of patients with FS (n = 21) enhances epidermal acantholysis and in vivo binding of FS autoantibodies as compared with a control group (n = 4). Another control group included 8 patients with pemphigus vulgaris (PV). RESULTS: Exposure of uninvolved skin of FS to UVB induces acantholysis (15/21 patients) with in vivo binding of IgG and C3 to the epidermal intercellular spaces (17/21 patients). Similar results were found in PV (6/8 patients). The test was negative in the control group. CONCLUSION: Sunlight exposure is harmful in the clinical course of patients with FS and those with PV. Protection from sunlight should be part of the treatment of these patients.

Effect of high sugar concentration on nitrogenase activity of Acetobacter diazotrophicus.

Acetobacter diazotrophicus is a nitrogen-fixing bacterium that growth inside sugar cane plant tissue where the sucrose concentration is approximately 10%. The influence of high sugar content on nitrogenase was measured in the presence of oxygen and of nitrogen added in the form of ammonium and amino acids. In all parameters analyzed, 10% sucrose protected nitrogenase against inhibition by oxygen, ammonium, some amino acids, and also to some extent by salt stress. The oxygen concentration at which inhibition occurred increased from 2 kPa in 1% glucose or gluconic acid, to 4 kPa (0.4 atm) in 10% sucrose. Nitrogenase activity was partially inhibited by increased ammonium levels (2.0, 5.0, and 10.0 mM) in the presence of 1% sucrose, but the cells maintained their nitrogenase activity at 10% sucrose. This could be explained by the slow ammonium assimilation by the cells in the presence of high sucrose concentrations, i.e., independent of its concentration between 2 and 10 mM, the assimilation of ammonium was reduced to one-third in cells grown with 10% sucrose. Some amino acids were also tested in the presence of 1 and 10% sucrose. Cells grown in 1% sucrose had their nitrogenase activity reduced by 50-98% in the presence of glutamic acid, glutamine, alanine, asparagine, or threonine, whereas with 10% sucrose, nitrogenase activity was increased by glutamic acid and was reduced by only 61-73% by the other amino acids. The effect of NaCl concentrations (0.0, 0.25, 0.5, 0.75, or 1.0%) was also studied at the two concentrations of sucrose. Nitrogenase activity and growth of A. diazotrophicus, which was visualized by the pellicle formation in semi-solid medium, showed sensitivity even to low NaCl concentrations, which was somewhat relieved at the higher sucrose level. These observations indicate different osmotolerance mechanisms for sucrose and salt.

Genetic Structure of Acetobacter diazotrophicus Populations and Identification of a New Genetically Distant Group.

A total of 55 isolates of Acetobacter diazotrophicus recovered from diverse sucrose-rich host plants and from mealybugs associated with sugarcane plants were characterized by the electrophoretic mobilities of 12 metabolic enzymes. We identified seven different electrophoretic types (ETs), six of which are closely related within a genetic distance of 0.195 and exhibit high DNA-DNA homology. The seventh ET was largely divergent, separated at a genetic distance of 0.53, and had only 54% DNA homology to the reference strain. Strains corresponding to ET 7 could represent a distinct nitrogen-fixing species of the genus Acetobacter. More genetic diversity was found in isolates from Brazil than in those from Mexico, probably due to the very different crop nitrogen fertilization levels used.

Improved methodology for isolation of Acetobacter diazotrophicus and confirmation of its endophytic habitat.

Nitrogen-free, semi-solid defined medium with crystallized cane sugar (100 g/l) supplemented with cane juice (5 ml/l) was the most selective for isolating Acetobacter diazotrophicus. Surveys of A. diazotrophicus using this medium showed that >10(3) cells/g fresh wt were present at all sites in all parts of the sugar cane plant and in all trash samples examined, reaching up to 10(7)/g. Additional samples, from forage grasses and cereals and from weed species collected within the sugar cane fields, were all negative. Heat treatment (50°C for 30 min) of the sugar cane setts did not affect A. diazotrophicus numbers within the plant. Nitrogenase activity of intact soil-plant systems in pots planted with heat-treated setts did not respond to inoculation with A. diazotrophicus. The endophytic habitat of this diazotroph and its propagation within the stem cuttings was confirmed.