Ana Carolina Ribeiro Dias

Efeitos da luz e temperatura na germinação de sementes de quatro espécies de plantas daninhas do gênero Digitaria

Brazil has the largest number of native species of Digitaria in the Americas. This genus is considered as a weed causing problems in various economic crops and can be found throughout Brazil in many different ecological situations. The object of this research was to evaluate the effects of light and temperature on the seed germination of four Digitaria weed species. The experiment was conducted in germination chambers using a factorial 4 x 2 scheme of treatments under four temperatures (25 oC constant, alternating 20-30 oC, 20-35 oC and 15-35 oC) with alternate light cycles (8h light/16h darkness) or absolute darkness. The weed species studied were Digitaria horizontalis Willd., D. bicornis (Lam.) Roem. & Schult., D.ciliaris (Retz.) Koel. and D. insularis (L.) Fedde. The percentage and speed of germination were evaluated up to 21 days after the start of the germination test. The four species showed differing seed physiological responses. D. bicornis and D. horizontalis required light for germination while D. ciliaris and D. insularis did not. The best temperatures for germination are 20-35 oC for D. bicornis and D. ciliaris, and 20-35 oC or 15-35 oC for D. horizontalis and D. insularis.

Dry Eye in Childhood: Epidemiological and Clinical Aspects

Because dry eye disease is rare in children and its pathogenesis is less well known than in adults, its diagnosis is often overlooked. It can occur in association with a number of congenital, autoimmune, endocrine, and inflammatory disorders, or under certain environmental and nutritional conditions. In some cases, early detection allows the underlying cause of the dry eye to be successfully treated and eliminated. In other cases, the disease may represent a lifelong problem, whose proper management can prevent ulceration and scarring of the ocular surface. Because of the association of pediatric dry eye with other conditions, a multidisciplinary approach to diagnosis and treatment is usually required. The purpose of this review is to enhance physician awareness of dry eye in children, to describe the most frequently associated conditions, and to discuss the diagnostic and therapeutic options available.

Tear film and ocular surface alterations in chronic users of antiglaucoma medications

PURPOSE Tear film can be altered by chronic medications that may disrupt the equilibrium responsible for the functioning of the lacrimal gland and ocular surface. The purpose of this study was to determine if antiglaucomatous chronic treatment induced alterations in the tear film and ocular surface. METHODS After informed consent, 21 patients using antiglaucomatous eye drops for more than 8 months and 20 age- and sex-matched volunteers without eye and systemic medications (control group) were enrolled. The data of ocular discomfort, fluorescein and lisamine green staining, tear film break-up time and Schirmer test were collected and compared by Students t test. The impression cytology data were graded and compared by chi-square test. RESULTS Patients chronically using antiglaucomatous medications presented with significant higher fluorescein staining (p=0.003), lisamine green staining (p=0.02) and lower TFBUT (p=0.001). The other compared parameters, including impression cytology were similar between the treated and control group (p>0.05). CONCLUSIONS The present study shows that the tear film and the ocular surface are altered in patients under antiglaucomatous medications. In common, all medications were preserved with benzalkonium chloride. Efforts to minimize the adverse effects of chronic use of antiglaucomatous drugs must be addressed.

Banana Peel as an Adsorbent for Removing Atrazine and Ametryne from Waters

The feasibility of using banana peel for removal of the pesticides atrazine and ametryne from river and treated waters has been demonstrated, allowing the design of an efficient, fast, and low-cost strategy for remediation of polluted waters. The conditions for removal of these pesticides in a laboratory scale were optimized as sample volume = 50 mL, banana mass = 3.0 g, stirring time = 40 min, and no pH adjustment necessary. KF(sor) values for atrazine and ametryne were evaluated as 35.8 and 54.1 μg g(-1) (μL mL(-1)) by using liquid scintillation spectrometry. Adsorption was also evaluated by LC-ESI-MS/MS. As quantification limits were 0.10 and 0.14 μg L(-1) for both pesticides, sample preconcentration was not needed. Linear analytical curves (up to 10 μg L(-1)), precise results (RSD < 4.5%), good recoveries (82.9-106.6%), and a > 90% removal efficiency were attained for both pesticides. Water samples collected near an intensively cultivated area were adequately remedied.

Germinação de sementes aéreas pequenas de trapoeraba (Commelina benghalensis)

Understanding basic information on weed biology related to plant emergence fluxes, seed dormancy causes and maximum depth for emergence may significantly contribute to creating rational strategies for weed management in agriculture. Thus, this work was developed to evaluate seed germination and seedling emergence of small aerial seeds of Bengal dayflower (Commelina benghalensis).Seeds were submitted to dormancy overcoming in sulfuric acid (periods of 1, 2, 3, 5 and 5 minutes) under different conditions of temperature (mean temperatures of 16.1; 18.6; 20.6; 23.1; 25.0; 26.9; 29.2; 31.1 and 33.6 oC), light (with or without), and seeding depth in the substrate (0, 5, 10, 20, 40 and 80 mm). The optimal temperature for Bengal dayflower germination was 25 oC. Light effects were not observed on seed germination. Positive consequences of seed treatment with sulfuric acid were not identified, considering different periods of exposure; indicating that Bengal dayflower seeds do not have tegument water impermeability. Seedling emergence is negative and linearly influenced by seeding depth in the substrate. Seedling emergence was not observed when seeds were 80 mm depth placed. Sand substrate favored seedling emergence.

The Role of Dyslipidemia on Ocular Surface, Lacrimal and Meibomian Gland Structure and Function

Purpose: Dyslipidemia is characterized by high lipid blood levels that are risk factors for cardiovascular diseases, which are leading causes of death. However, it is unclear whether dyslipidemia is a cause of the dry eye syndrome (DES). Therefore we determined in transgenic mice models of dyslipidemia, whether there is an association with DES development. Methods: Dyslipidemic models included male and female adult mice overexpressing apolipoprotein CIII (Apo CIII), LDL receptor knockout (LDLR-KO) and ApoE knockout (ApoE-KO). They were compared with age- and gender-matched C57BL/6 mice. Ocular health was evaluated based on corneal slit lamp assessment, phenol red thread test (PRT) and impression cytology. Blood lipid profiles and histology of meibomian and lacrimal glands were also evaluated. Effects of high-fat diet and aging were observed in LDLR-KO and ApoCIII strains, respectively. Results: Body weight and lacrimal gland weight were significantly higher in male mice compared to females of the same strain (P < 0.05). Body weight was significantly lower in LDLRKO mice receiving high lipid diet compared to their controls (P = 0.0043). ApoE-KO were hypercholesterolemic and ApoCIII hypertriglyceridemic while LDLR-KO showed increases in both parameters. The PRT test was lower in male LDLR-KO mice with high-fat diet than control mice with standard diet (P = 0.0273). Aging did not affect lacrimal structural or functional parameters of ApoCIII strain. Conclusions: DES development is not solely dependent on dyslipidemia in relevant mice models promoting this condition. On the other hand, lacrimal gland structure and function are differentially impacted by lipid profile changes in male and female mice. This dissociation suggests that other factors beside dyslipidemia impact on tear film dysfunction and DES development.

Uptake, translocation, and control of trumpet flower (Tecoma stans) with aminocyclopyrachlor.

To gain a better understanding of the physiology of the herbicide aminocyclopyrachlor in young plants of trumpet flower, the uptake and translocation were evaluated after the application of herbicide. This was determined by treating individual leaves with formulated herbicides plus 14C-aminocyclopyrachlor after the application of the formulated herbicide. This experiment used a randomized experimental design with three replications. In addition, field studies were conducted to assess the effectiveness of foliar applications of aminocyclopyrachlor in association with metsulfuton-methyl. The plant absorbed 20% of the herbicide applied. The translocation percentage did not surpass 5% of the total amount applied. Only 1% of the herbicide applied was translocated to the roots. Rate of 40 + 13 g a.i. 100 L−1 of aminocyclopyrachlor+metsulfuron-methyl was effective to control T. stans.

Eficácia e pH de caldas de glifosato após a adição de fertilizantes nitrogenados e utilização de pulverizador pressurizado por CO2

This work was developed with the objective of evaluating the efficacy and the pH of glyphosate spray solutions after the addition of nitrogen fertilizers and the use of CO2-pressurized sprayer. In field conditions, two rates of glyphosate (360 and 720 g ha-1) were applied either alone or combined with two concentrations of urea (2.5 and 5.0 g L-1) or ammonium sulfate (7.5 and 15.0 g L-1). In laboratory, the pH of the glyphosate solutions was measured after using different concentrations of the product and nitrogen fertilizers and after using a CO2-pressurized sprayer. For all field condition evaluations, the lowest glyphosate rate had higher biological efficacy after the addition of ammonium sulfate (15 g L-1) to the spray solution. Urea (5 g L-1) promoted benefits only at the 28th-day evaluation. In laboratory, the increase of glyphosate concentration promoted gradual acidification of the spray solution, which stabilized at pH 4.5. Ammonium sulfate caused minor acidification of the herbicide solution, whereas urea did not change the pH. The use of CO2-pressurized sprayer had small effect on the solutions pH. Highest glyphosate efficacy identified after the addition of nitrogen fertilizers has little relation with changes on the solutions pH.

Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

Insulin replacement restores the vesicular secretory apparatus in the diabetic rat lacrimal gland

PURPOSE In the lacrimal gland (LG) acinar cells, signaling regulates the release of secretory vesicles through specific Rab and SNARE exocytotic proteins. In diabetes mellitus (DM), the LGs are dysfunctional. The aim of this work was to determine if secretory apparatus changes were associated with any effects on the secretory vesicles (SV) in diabetic rats as well as the expression levels of constituent Rab and members of the SNARE family, and if insulin supplementation reversed those changes. METHODS DM was induced in male Wistar rats with an intravenous dose of streptozotocin (60 mg/kg). One of the two diabetic groups was then treated every other day with insulin (1 IU). A third control group was injected with vehicle. After 10 weeks, Western blotting and RT-PCR were used to compared the Rab and SNARE secretory factor levels in the LGs. Transmission electron microscopy evaluated acinar cell SV density and integrity. RESULTS In the diabetes mellitus group, there were fewer and enlarged SV. The Rab 27b, Rab 3d, and syntaxin-1 protein expression declined in the rats with diabetes mellitus. Insulin treatment restored the SV density and the Rab 27b and syntaxin expression to their control protein levels, whereas the Vamp 2 mRNA expression increased above the control levels. CONCLUSIONS Diabetes mellitus LG changes were associated with the declines in protein expression levels that were involved in supporting exocytosis and vesicular formation. They were partially reversed by insulin replacement therapy. These findings may help to improve therapeutic management of dry eye in diabetes mellitus.