RESUMO: O estresse causado por temperaturas extremas configura-se como um dos principais elementos que limitam a distribuição geográfica e o crescimento sazonal de diversas plantas, provocando severo atraso no seu desenvolvimento, reduzindo a taxa fotossintética e sinalizando a síntese de compostos de defesa. Diante das mudanças ambientais em curso e dos danos que essas mudanças podem causar na fisiologia e no crescimento das plantas, o objetivo deste trabalho foi compreender as interações entre temperatura, fisiologia e crescimento, bem como caracterizar o impacto que a alteração da temperatura exerce sobre o desenvolvimento inicial de Vernonia ferruginea Less. Para determinação de parâmetros fisiológicos e de crescimento, plântulas dessa espécie foram acondicionadas em câmaras de germinação com as temperaturas constantes dos tratamentos previamente ajustadas (10, 20, 25, 30 e 35 oC) por 60 dias. A faixa ótima de temperatura para crescimento inicial de V. ferruginea está entre 25 e 30 oC. O estresse causado pelas temperaturas subótimas e supraótimas afetou a homeostase celular e provocou atraso no crescimento e desenvolvimento das plântulas. Em situações estressantes, observou-se a inibição do crescimento e a ativação de mecanismos de resposta para a adaptação e manutenção da homeostase celular mediante o acúmulo do osmoprotetor prolina, e carboidratos solúveis. Adicionalmente, as plantas apresentaram desenvolvimento normal dentro de uma ampla faixa de temperatura, apesar do atraso no desenvolvimento, da alteração nas trocas gasosas e na síntese de substâncias relacionadas ao sistema de defesa.

ABSTRACT: Stress caused by extreme temperatures is one of the main elements that limit the geographical distribution and the seasonal growth of several plants, causing a severe delay in their development, reducing the photosynthetic rate and signaling the synthesis of defense compounds. Considering the current environmental changes and the damages that these changes can cause in plant physiology and growth, the objective of this work was to understand the interactions between temperature, physiology and growth, and to characterize the impact of temperature changes on the initial development of Vernonia ferruginea Less. Seedlings of this species were conditioned in germination chambers at previously adjusted constant temperatures (10, 20, 25, 30, and 35 oC) for sixty days, in order to evaluate physiological and growth parameters. The optimum temperature range for the initial growth of V. ferruginea is between 25 and 30 oC. The stress caused by sub-optimal and over-optimal temperatures affected cell homeostasis and caused a delay in the growth and development of seedlings. In stressful situations, growth inhibition and the activation of response mechanisms were observed for the adaptation and maintenance of cellular homeostasis through the accumulation of the proline osmoprotectant and soluble carbohydrates. Additionally, plants presented a normal development within a wide temperature range, despite the development delay, the change in gas exchanges and the synthesis of substances related to the defense system.

RESUMO A espécie Digitaria insularis tem sido selecionada por aplicações frequentes de glyphosate, tanto em áreas de plantio direto como em pomares de frutíferas. Assim, objetivou-se neste trabalho o controle de diferentes populações de D. insularis pelo herbicida glyphosate, isolado e em mistura com quizalofop-p-tefuryl, além de classificar as populações quanto à sensibilidade (suscetível, medianamente suscetível ou tolerante) ao glyphosate e analisar características morfoanatômicas das folhas das populações. Para o experimento de controle químico, o delineamento experimental foi o inteiramente casualizado com quatro repetições, em esquema fatorial 12 x 4. Doze populações de D. insularis foram pulverizadas com glyphosate isolado (1,44 e 2,16 kg e.a. ha-1) e em mistura (2,16 kg e.a. ha-1) com quizalofop-p-tefuryl (0,12 kg i.a. ha-1). Ademais, uma testemunha sem aplicação foi mantida para cada população. Em laboratório, foram realizadas análises morfoanatômicas e de quantificação de cerosidade das folhas. As populações 3, 5, 6 e 8 foram consideradas suscetíveis ao glyphosate; 9, 10 e 12, medianamente suscetíveis; e 1, 2, 4, 7 e 11, tolerantes. Todas as populações apresentaram as mesmas características morfológicas, mas diferiram nas anatômicas e na quantidade de cera. Contudo, as populações dentro de cada grupo (suscetíveis, medianamente suscetíveis ou tolerantes) não tiveram características semelhantes que justificassem a resposta diferencial ao herbicida glyphosate. Diferenças relacionadas com a translocação dos herbicidas e/ou fisiologia das plantas poderiam explicar os resultados do controle químico dessas populações.

ABSTRACT Digitaria insularis has been selected by frequent glyphosate applications both in no-till areas and in fruit orchards. The objective of this paper was to evaluate control efficacy of D. insularis populations by glyphosate, alone and mixed with quizalofop-p-tefuryl, as well as classify them for herbicide sensitivity as susceptible, moderately susceptible and tolerant. This study also aimed to evaluate the relations between herbicide sensitivity and morphoanatomic features of leaf tissues. For chemical control, the experiment was conducted in a completely randomized design, with a 12 x 4 factorial arrangement with four replications. Twelve populations of D. insularis were treated with glyphosate alone at two concentrations (1.44 and 2.16 kg a.e. ha-1) and with the mixture of glyphosate (2.16 kg a.e. ha-1) and quizalofop-p-tefuryl (0.12 kg a.i. ha-1). One treatment without herbicide application was maintained for each plant population. Evaluations about the morphoanatomic features and wax content of leaves from the twelve plant populations were made under laboratory conditions. Populations 3, 5, 6 and 8 were considered to be susceptible; 9, 10 and 12 were considered as moderately susceptible; 1, 2, 4, 7 and 11 were considered tolerant to glyphosate. However, populations within each group (susceptible, moderately susceptible and tolerant) did not have similar characteristics that justify their response to glyphosate. Differences relative to herbicide translocation and/or plant physiology could account for the chemical control results for these populations.

Early diagnosis plays a vital role in controlling tuberculosis. The conventional methodology is slow, with results taking several weeks, in addition to having low sensitivity, especially in clinical paucibacillary samples. The objective of this study was to evaluate the use of polymerase chain reaction (PCR) on solid medium culture for a rapid diagnosis of tuberculosis, mainly in cases of negative sputum smears. Forty sputum samples were collected from inpatients with tuberculosis treated for less than 2 days. Bacilloscopy, PCR for sputum, culture on Löwestein-Jensen (LJ) solid medium, and daily PCR from culture were performed on each sample. DNA extracted from the BCG vaccine, which contains attenuated bacillus Calmette-Guérin, was used as the positive control. Smear microscopy showed 68.6% sensitivity, 80% specificity, 96% positive predictive value, and 26.7% negative predictive value, with culture on LJ medium as the gold standard. Culture at day 28 showed 74.3% sensitivity and 100% specificity. PCR of DNA extracted from sputum amplified a 1027-bp fragment of the 16s RNA gene, showing 22.9% sensitivity and 60% specificity. PCR performed with DNA extracted from daily culture showed that, from the 17th to the 40th day, the sensitivity (85.7%) and specificity (60%) were constant. We conclude that a 17-day culture is a good choice for rapid diagnosis and to interfere with the transmission chain of tuberculosis.

Aluminum (Al3+) overload is frequently associated with lipid peroxidation and neurological disorders. Aluminum accumulation is also reported to be related to renal impairment, anemia and other clinical complications in hemodialysis patients. The aim of the present study was to determine the degree of lipid peroxidation, platelet aggregation and serum aluminum in patients receiving regular hemodialytic treatment. The level of plasma lipid peroxidation was evaluated on the basis of thiobarbituric acid reactive substances (TBARS). Mean platelet peroxidation in patients undergoing hemodialysis was significantly higher than in normal controls (2.7 ± 0.03 vs 1.8 ± 0.06 nmol/l, P<0.05). Platelet aggregation and serum aluminum levels were determined by a turbidimetric method and atomic absorption spectrophotometry, respectively. Serum aluminum was significantly higher in patients than in normal controls (44.5 ± 29 vs 10.8 ± 2.5 µg/l, P<0.05). Human blood platelets were stimulated with collagen (2.2 µg/ml), adenosine diphosphate (6 µM) and epinephrine (6 µM) and showed reduced function with the three agonists utilized. No correlation between aluminum levels and platelet aggregation or between aluminum and peroxidation was observed in hemodialyzed patients.