Effects of different light levels on the initial growth and photosynthesis of Croton urucurana Baill. in southeastern Brazil

Four levels of shading (full sunlight (0%), 30, 50, 70% of solar radiation interception on growth, chlorophyll concentration and photosynthetic rate were studied in Croton urucurana Baill., a pioneer plant species. This species seedlings are of potential interest for reforestation projects and recovery of degraded areas. The seedlings were grown in pots containing soil and sand (2:1) and later transferred to plastic bags of 3 dm³ and submitted to different levels of shading (30, 50, 70%) of solar radiation and full sunlight, as control. The experimental design was completely randomized with five replicates and each experimental unit was composed of five plants. The results suggest that plants submitted to 70% shading showed higher dry weight accumulation in leaf and root, and higher plant height and leaf area. However, the seedlings root system showed higher dry biomass under full sunlight. It was observed a tendency to increase chlorophyll concentration and to decrease photosynthetic rate with the increase of the shading level.

Photosynthesis and carbon gain under contrasting light levels in seedlings of a pioneer and a climax tree from a Brazilian Semideciduous Tropical Forest

In this study we evaluated photosynthetic characteristics and patterns of biomass accumulation in seedlings of two tree species from a Semideciduous Tropical Forest of Brazil. Seedlings of Trema micrantha (L.) Blum. (pioneer) and Hymenaea courbaril (L.) var. stilbocarpa (Hayne) Lee & Langenh. (climax) were grown for 4 months under low light (LL) (5%-8% of sunlight) and high light (HL) (100% of sunlight). Under HL, T. micrantha showed higher CO2 assimilation rates (A CO2) and light saturation than H. courbaril. Under LL, A CO2 were higher in H. courbaril. Under LL, total chlorophyll and carotenoid contents per unit leaf area were higher in H. courbaril. Chlorophyll a/b ratio was higher in T. micrantha under both light regimes. A CO2 and Fv/Fm ratio at both pre-dawn and midday in H. coubaril were lower in HL indicating chronic photoinhibition. Thus, the climax species was more susceptible to photoinhibition than the pioneer. However, H. courbaril produced higher total biomass under both treatments showing high efficiency in the maintenance of a positive carbon balance. Thus, both species expressed characteristics that favor growth under conditions that resemble their natural microenvironments, but H. courbaril also grew under HL. The ecophysiological range of responses to contrasting light levels of this climax plant seems to be broader than generally observed for other rainforest climax species. We propose that this could be related to the particular spatio-temporal light regime of the semideciduous forests.

The influence of light spectra, UV-A, and growth regulators on the in vitro seed germination of Senecio cineraria DC.

This study was carried out to investigate the effects of light spectra, additional UV-A, and different growth regulators on the in vitro germination of Senecio cineraria DC. Seeds were surface-sterilized and inoculated in MS medium to evaluate the following light spectra: white, white plus UV-A, blue, green, red or darkness. The maximum germinability was obtained using MS0 medium under white light (30%) and MS + 0.3 mg L-1 GA3 in the absence of light (30.5%). S. cineraria seeds were indifferent to light. Blue and green lights inhibited germination. Different concentrations of gibberellic acid (GA3) (0.1; 0.4; 0.6; 0.8; 1.0 and 2.0 mg L-1) and indole-3-acetic acid IAA (0.1; 0.3 and 1.0 mg L-1) were evaluated under white light and darkness. No concentration of GA3 enhanced seed germination percentage under white light. However, when the seeds were maintained in darkness, GA3 improved germination responses in all tested concentrations, except at 1.0 mg L-1. Under white light, these concentrations also increased the germination time and reduced germination rate. Germination rate, under light or darkness, was lower using IAA compared with GA3.

Selection of full-sib families of Panicum maximum Jacq under low light conditions

The silvopastoral system is a viable technological alternative to extensive cattle grazing, however, for it to be successful, forage grass genotypes adapted to reduced light need to be identified. The objective of this study was to select progenies of Panicum maximum tolerant to low light conditions for use in breeding programs and to study the genetic control and performance of some traits associated with shade tolerance. Six full-sib progenies were evaluated in full sun, 50% and 70% of light reduction in pots and subjected to cuttings. Progeny genotypic values ​​(GV) increased with light reduction in relation to plant height (H) and specific leaf area (SLA). The traits total dry mass accumulation (DM) and leaf dry mass accumulation (LDM) had GV higher in 50% shade and intermediate in 70% shade. The GV of tiller number (TIL) and root dry mass accumulation (RDM) decreased with light reduction. The highest positive correlations were obtained for the traits H and RDM with SLA and DM; the highest negative correlations were between TIL and SLA and RDM, and H and LDM. The progenies showed higher tolerance to 50% light reduction and, among them, two stood out and will be used in breeding programs. It was also found that it is not necessary to evaluate some traits under all light conditions. All traits had high broad sense heritability and high genotypic correlation between progenies in all light intensities. There is genetic difference among the progenies regarding the response to different light intensities, which will allow selection for shade tolerance

HIV testing and clinical status upon admission to a specialized health care unit in Pará, Brazil

OBJECTIVE To analyze the clinical and laboratory characteristics of HIV-infected individuals upon admission to a reference health care center.METHODS This cross-sectional study was conducted between 1999 and 2010 on 527 individuals with confirmed serological diagnosis of HIV infection who were enrolled in an outpatient health care service in Santarém, PA, Northern Brazil. Data were collected from medical records and included the reason for HIV testing, clinical status, and count of peripheral CD4+ T lymphocytes upon enrollment. The data were divided into three groups, according to the patient’s year of admission – P1 (1999-2002), P2 (2003-2006), and P3 (2007-2010) – for comparative analysis of the variables of interest.RESULTS In the study group, 62.0% of the patients were assigned to the P3 group. The reason for undergoing HIV testing differed between genders. In the male population, most tests were conducted because of the presence of symptoms suggesting infection. Among women, tests were the result of knowledge of the partner’s seropositive status in groups P1 and P2. Higher proportion of women undergoing testing because of symptoms of HIV/AIDS infection abolished the difference between genders in the most recent period. A higher percentage of patients enrolling at a more advanced stage of the disease was observed in P3.CONCLUSIONS Despite the increased awareness of the number of HIV/AIDS cases, these patients have identified their serological status late and were admitted to health care units with active disease. The HIV/AIDS epidemic in Pará presents specificities in its progression that indicate the complex characteristics of the epidemic in the Northern region of Brazil and across the country.

Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP": during a five year period (1988-1993)

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serologycal assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993,18 (25.71 %) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

Congenital cytomegalovirus infection in a neonatal intensive care unit in Brazil evaluated by PCR and association with perinatal aspects

Cytomegalovirus (CMV) infection is the most common congenital infection, affecting 0.4% to 2.3% newborns. Most of them are asymptomatic at birth, but later 10% develop handicaps, mainly neurological disturbances. Our aim was to determine the prevalence of CMV shed in urine of newborns from a neonatal intensive care unit using the polymerase chain reaction (PCR) and correlate positive cases to some perinatal aspects. Urine samples obtained at first week of life were processed according to a PCR protocol. Perinatal data were collected retrospectively from medical records. Twenty of the 292 cases (6.8%) were CMV-DNA positive. There was no statistical difference between newborns with and without CMV congenital infection concerning birth weight (p=0.11), gestational age (p=0.11), Apgar scores in the first and fifth minutes of life (p=0.99 and 0.16), mother's age (p=0.67) and gestational history. Moreover, CMV congenital infection was neither related to gender (p=0.55) nor to low weight (<2,500g) at birth (p=0.13). This high prevalence of CMV congenital infection (6.8%) could be due to the high sensitivity of PCR technique, the low socioeconomic level of studied population or the severe clinical status of these newborns.

Lack of methicillin-resistant Staphylococcus aureus nasal carriage among patients at a primary-healthcare unit in Porto Alegre, Brazil

INTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a pathogen in individuals without traditional risk factors. MATERIAL AND METHODS: MRSA nasal carriage was assessed in individuals consulting at a Primary Health Unit in Brazil. RESULTS: A total of 336 individuals were included: 136 were tested only for MRSA and 200 for any S. aureus. No MRSA was found among the 336 individuals and 23 (11.5%) of 200 were colonized by S. aureus. DISCUSSION: Low prevalence rates have been found in non-hospitalized individuals, but MRSA surveillance should be encouraged to monitor clinical and molecular epidemiology of CA- MRSA.

HIV-1-mother-to-child transmission and associated characteristics in a public maternity unit in Presidente Prudente, Brazil

In children, vertical transmission is the main form of HIV infection. Our aim was to determine the prevalence of HIV-1 vertical transmission in mother-infant pairs in a public maternity ward in Presidente Prudente, SP. Additionally; we sought to identify characteristics associated with this form of transmission. The files of 86 HIV-1-infected mothers and their newborns referred to a Public Hospital from March 2002 to March 2007 were analyzed. The HIV-1-RNA viral load of the newborns was determined by bDNA. The HIV-1 vertical-transmission rate was 4.6%. Children that were born in the pre-term period and breastfed were at a higher risk of HIV-1 infection (p = 0.005 and p = 0.017 respectively) than children born at term and not breastfed. Prophylactic therapy with zidovudine after birth for newborns was associated with a lower risk of infection (p = 0.003). The number of newborns weighing < 2,500 g was significantly higher for infected children (p = 0.008) than for non-infected newborns. About 22.9% of mothers did not know the HIV-1 status of their newborns eight months after delivery. The study suggests that it is necessary to increase the identification of HIV-1 infection in pregnant women and their newborns as well as to offer and explain the benefits of ARV prophylaxis.

Toxocariasis in children attending a Public Health Service Pneumology Unit in Paraná State, Brazil

The enzyme-linked immunosorbent assay (ELISA) is the most widely used tool to detect anti-Toxocara IgG antibodies for both serodiagnostic and seroepidemiological surveys on human toxocariasis. In the last eight years a high prevalence of toxocariasis (32.2-56.0%) has been reported in children attending public health units from municipalities in the state of Paraná, Brazil. Therefore, the aim of this work was to compare the frequency found among the general child population with that of children attending a public pneumology service in Maringá, Paraná, Brazil and describe the laboratorial, clinical and epidemiological findings. The research was conducted at the Consórcio Público Intermunicipal de Saúde do Setentrião Paranaense (CISAMUSEP) from July 2009 to July 2010 among children aged between one and 15 years. From a total of 167 children studied, only 4.2% (7/167) tested positive for anti-Toxocara spp. IgG antibodies and presented mild eosinophilia (2/7), increased serum IgE levels (6/7) and a positive allergy test for mites (5/7). The presence of pets (dogs or cats) at home did not correlate with the seroprevalence. In conclusion, cases of toxocariasis involving the respiratory tract are rare in children attending a public health pneumology unit in the northwestern region of Paraná State, despite the high prevalence of this type of toxocariasis among the infantile population attending Basic Health Units in the same geographical area.

INVENTORY OF MOSQUITOES (DIPTERA: CULICIDAE) IN CONSERVATION UNITS IN BRAZILIAN TROPICAL DRY FORESTS

In Brazil, most studies of the Culicidae family are concentrated in rainforest regions. As such, there is a lack of knowledge regarding the diversity of Culicidae in regions with different climatic and vegetational characteristics. The aim of this study was to compile an inventory of Culicidae in protected areas of the semi-arid region of the state of Minas Gerais, Brazil, in order to better understand the diversity of the family within this region. The study was conducted across four protected areas in the northern region of the state, in tropical dry forest (TDF) fragments. Sampling methods included Shannon trap and CDC light trap, as well as active collection. A total of 11,219 mosquito specimens were collected between August 2008 and July 2012, belonging to 11 genera and 45 species; 15 new records for the state of Minas Gerais were registered, as well as 26 new records for semi-arid regions within the state. The high number of new Culicidae records in this region demonstrates the importance of inventory studies for increasing the knowledge of culicid biodiversity in Minas Gerais, and in particular within semi-arid regions of the state.

Influence of light conditions on adult mortality and egg-laying of Triatoma brasiliensis neiva, 1911 (Hemiptera: Reduviidae: Triatominae)

We compared, for Triatoma brasiliensis, the egg-laying process and the mortality of adults under conditions of almost permanent darkness and with normal laboratory luminosity. Mortality did not differ between groups. The egg-laying per vial and per female was significantly greater in the group of normal luminosity. We consider that it is not recommendable to keep the adults of this species under complete darkness. Other biological aspects should be analysed in relation to luminosity.

Treatment of T. cruzi infected human platelet concentrates with aminomethyltrimethyl psoralen (AMT) and ultravioleta (UV-A) light: preliminary results

The present measures adopted to prevent transfusion-associated Chagas' disease include screening of blood donors. and/or the inactivation of T. cruzi in collected blood using gentian violet (GV) as a trypanocidal agent. In this study, we investigated the efficacy of the combined use of AMT and UV-A in inactirating T. cruzi in infected human platelet cuncentrates. Human platelet concentrates were infected with T. cruzi (2x10/ml) of the Y strain transfered to PL 269 (Fenwal Laboratories) containers and treated with GV (250řg,/ml). and ascorbic acid (1 mg/ml); GV. ascorbic acid and UV-A; GV and UV-A; AMT (40/tG/ml) and ascorbic acid; AMT, ascorbic acid and UV-A; AMT and UV-A; UV-A alone; and untreated (control). All UV-A treated platelet concentrates were exposed to UV-A doses of 24, 92, 184, 276, 368 and 644 kj/m². and the microscopical research of active T. cruzi was performed, using the microhematocrit technique, 1, 6 and 24 hours after each treatment. A high number of active forms of T. cruzi was observed in all condictions, except when GV was used as the trypanocidal agent, providing evidence of the failure of AMT and UV-A in inactivating T cruzi in infected human platelet concentrates.