The effect of environment on development and survival of pupae of the necrophagous fly Ophyra albuquerquei Lopes (Diptera, Muscidae)

The effect of environment on development and survival of pupae of the necrophagous fly Ophyra albuquerquei Lopes (Diptera, Muscidae). Species of Ophyra Robineau-Desvoidy, 1830 are found in decomposing bodies, usually in fresh, bloated and decay stages. Ophyra albuquerquei Lopes, for example, can be found in animal carcasses. The influence of environmental factors has not been evaluated in puparia of O. albuquerquei. Thus, the focus of this work was motivated by the need for models to predict the development of a necrophagous insect as a function of abiotic factors. Colonies of O. albuquerquei were maintained in the laboratory to obtain pupae. On the tenth day of each month 200 pupae, divided equally into 10 glass jars, were exposed to the environment and checked daily for adult emergence of each sample. We concluded that the high survival rate observed suggested that the diets used for rearing the larvae and maintaining the adults were appropriate. Also, the data adjusted to robust generalized linear models and there were no interruptions of O. albuquerquei pupae development within the limits of temperatures studied in southern Rio Grande do Sul, given the high survival presented.

Effect of compaction on microbial activity and carbon and nitrogen transformations in two oxisols with different mineralogy

The use of machinery in agricultural and forest management activities frequently increases soil compaction, resulting in greater soil density and microporosity, which in turn reduces hydraulic conductivity and O2 and CO2 diffusion rates, among other negative effects. Thus, soil compaction has the potential to affect soil microbial activity and the processes involved in organic matter decomposition and nutrient cycling. This study was carried out under controlled conditions to evaluate the effect of soil compaction on microbial activity and carbon (C) and nitrogen (N) mineralization. Two Oxisols with different mineralogy were utilized: a clayey oxidic-gibbsitic Typic Acrustox and a clayey kaolinitic Xantic Haplustox (Latossolo Vermelho-Amarelo ácrico - LVA, and Latossolo Amarelo distrófico - LA, respectively, in the Brazil Soil Classification System). Eight treatments (compaction levels) were assessed for each soil type in a complete block design, with six repetitions. The experimental unit consisted of PVC rings (height 6 cm, internal diameter 4.55 cm, volume 97.6 cm³). The PVC rings were filled with enough soil mass to reach a final density of 1.05 and 1.10 kg dm-3, respectively, in the LVA and LA. Then the soil samples were wetted (0.20 kg kg-1 = 80 % of field capacity) and compacted by a hydraulic press at pressures of 0, 60, 120, 240, 360, 540, 720 and 900 kPa. After soil compression the new bulk density was calculated according to the new volume occupied by the soil. Subsequently each PVC ring was placed within a 1 L plastic pot which was then tightly closed. The soils were incubated under aerobic conditions for 35 days and the basal respiration rate (CO2-C production) was estimated in the last two weeks. After the incubation period, the following soil chemical and microbiological properties were detremined: soil microbial biomass C (C MIC), total soil organic C (TOC), total N, and mineral N (NH4+-N and NO3--N). After that, mineral N, organic N and the rate of net N mineralization was calculated. Soil compaction increased NH4+-N and net N mineralization in both, LVA and LA, and NO3--N in the LVA; diminished the rate of TOC loss in both soils and the concentration of NO3--N in the LA and CO2-C in the LVA. It also decreased the C MIC at higher compaction levels in the LA. Thus, soil compaction decreases the TOC turnover probably due to increased physical protection of soil organic matter and lower aerobic microbial activity. Therefore, it is possible to conclude that under controlled conditions, the oxidic-gibbsitic Oxisol (LVA) was more susceptible to the effects of high compaction than the kaolinitic (LA) as far as organic matter cycling is concerned; and compaction pressures above 540 kPa reduced the total and organic nitrogen in the kaolinitic soil (LA), which was attributed to gaseous N losses.

Temporary effect of chiseling on the compaction of a Rhodic Hapludox under no-tillage

Mechanical chiseling has been used to alleviate the effects of compaction in soils under no-tillage (NT). However, its effect on the soil physical properties does not seem to have a defined duration period. The purpose of this study was to evaluate the behavior of the bulk density (BD) and degree of compaction (DC) at different soil depths, after chiseling in no-tillage, for one year. The experiment was performed in Ponta Grossa, Paraná State, Brazil, using an Oxisol (Rhodic Hapludox). Bulk density and DC were previously measured in an area under NT for 16 years, then immediately after chiseling (CHI) in May 2009, six months after chiseling (CHI6M) in October 2009 and one year after chiseling (CHI12M) in May 2010. In the layers 0.0-0.10, 0.10-0.20 and 0.20-0.30 m, there was a significant BD reduction CHI and a marked increase CHI6M. The BD values measured CHI12M were similar to those before tillage. Chiseling reduced the DC in the layers 0.0-0.10 m and 0.10-0.20 m, but returned to the initial values one year later. During the evaluation periods CHI, CHI6M and CHI12M, the BD increased in the layer 0.30-0.40 m, compared with NT. The highest DC values were observed six months after chiseling; nevertheless the structural recovery of the soil was considerable, possibly due to the high degree of soil resilience and the influence of the wetting and drying cycles detected in the study period. The chiseling effects, evaluated by BD and DC, lasted less than one year, i.e., the beneficial short-term effects of chiseling on the reduction of the surface BD increased the risk of compaction in deeper soil layers.

Detrimental effect of rutin on Anticarsia gemmatalis

Behavioral and nutritional effect of rutin (quercetin 3-O-rutinosídeo) on Anticarsia gemmatalis Hübner (Lep.: Noctuidae), a major soybean defoliator in Brazil, was evaluated from the third instar to pupation. Rutin is one of the flavonol glycosides identified in the leaves of the wild soybean PI 227687. Larval weight and amount of ingested food decreased as rutin concentration in the diet increase. An interactive effect between feeding time and diet (treatment) was observed on insect growth; when larvae fed on pure-diet, feeding time elongation resulted in heavier pupae. Differently, the weight of larvae fed on rutin-diet remained almost stable, in spite of eating for longer. A. gemmatalis growth was negatively influenced by rutin-diet not only by feeding deterrence but also by post-ingestive effect on insect growth, since after adjustment of pupal weight by the amount of ingested food (covariate), the effect of diet remained significant. Rutin negatively influenced A. gemmatalis growth as result of pre-ingestive effect, indicated by reduction in food consumption, and post-ingestive effect, indicated by lower conversion of ingested food into body mass and food assimilation.

NMR investigation and theoretical calculations of the effect of solvent on the conformational analysis of 4',7-di-hydroxy-8-prenylflavan

The NMR conformational study of 4',7-di-hydroxy-8-prenylflavan 1 was carried out in acetone-d6, DMSO-d6 and CDCl3 which enabled the proposition of three conformations, namely 1a, 1b and 1c, differing in the position of the prenyl group. Geometry optimizations performed using AM1 method showed that 1a (deltaHf = -86.2 kcal/mol) is as stable as 1b (deltaHf = -85.1 kcal/mol) and 1c (deltaHf = -85.4 kcal/mol). When the solvent was included, the calculations showed that the solute-solvent interactions could be explained either in the light of the electronic intermolecular delocalization or the electrostatic character between solute and solvent. Theoretical calculations (HF/6-31G*, deltaFT/BLYP/6-31G*, and deltaFT/B3LYP/6-31G*) showed that the combination of these types of interactions present in each solute-solvent system, dependent on the chemical properties of the solvent, lead to different spatial arrangements of the prenyl group, which in turn determined the conformation of 1.

Effect of ethephon on hardening of Pachystroma longifolium seedlings

Immediately after planting, tree seedlings face adverse environmental and biotic stresses that must be overcome to ensure survival and to yield a desirable growth. Hardening practices in the nursery may help improve seedling stress resistance through reduction of aboveground plant tissues and increased root volume and biomass. We conducted an assay to quantify changes in the morphogenesis following application of ethephon on seedlings of Pachystroma longifolium (Ness) I. M. Johnst.during hardening. The results showed no effect of the ethephon treatments on the number of leaves but a reduction of up to 50% in seedling height increment, and an increase in stem diameter increment of up to 44% with the 600 mg L-1 ethephon treatment, which consequently altered seedling Dickson Quality Index. Our results indicate that ethephon may help to promote desired morphological changes that occur during seedling hardening in nurseries.

Effect of adjuvants on the amount of air included in droplets generated by spray nozzles

The air included in droplets generated by spray nozzles directly int0erferes in transport, deposition and retention of the droplets after its impact on the target. The objective of this study was to analyze the interference of adjuvants in the amount of air included in droplets generated by spray nozzles. The treatments were composed by four spray solutions containing mineral oil, vegetable oil, surfactant and water, and three spray nozzles, two air induction type and one pre-orifice. The air included was calculated by the difference between the volume of spray mix (air plus liquid) and only the liquid, which was made by means of sprayed samples captured in a funnel and collected in a graduated cylinder. The surface tension was estimated by the gravimetric method using a precision scale and a graduated pipette. The surfactant provided the largest percentage of air included in the spray. For the surface tension, the mineral oil and the surfactant had the lowest values. It was concluded that the use of adjuvants had a direct influence on the percentage of air included. In addition, products with greater ability to reduce surface tension and to form homogeneous solutions provided the increase in the percentage of air included in the droplet.

Prophylactic effect of levamisole on rainbow trout (Oncorhynchus mykiss) against Yersinia ruckeri

Alteration in the relative percentage of survival (RPS) rate of rainbow trout (Oncorhynchus mykiss) exposed to 5, 10 and 25µg ml-1 levamisole for 2 h against Yersinia ruckeri was investigated. The average weight of the 120 fish used in this study was 6.3g. Upon challenge with a virulent strain, the relative survival percentage of respectively 83.3%, 86.7% and 76.6% was recorded. The results suggest that the application of levamisole in fish farms could increase resistance to infection of fish and offer economic benefits.

Effect of taxol on chromosome aberrations induced by gamma radiation or by doxorubicin in Chinese hamster ovary cells

Combined therapy with radiation and chemotherapy has being increasingly used in cancer treatment. The effect of combinations of taxol (0.08 mug/ml) with doxorubicin (DXR, 0.5 or 1.0 mug/ml) or gamma radiation (20 or 40 cGy) was examined in two different treatment schedules (pretreatment or simultaneous treatment) using Chinese hamster ovary (CHO) cells treated at the G2 phase of the cell cycle. The results showed that taxol did not have a radiosensitizing effect on the chromosomal aberrations induced by gamma radiation nor did it have a potentiating effect on the chromosomal aberrations induced by DXR in CHO cells treated in the G2 phase of the cell cycle

Effect of urea on biomimetic aggregates

The effect of urea on biomimetic aggregates (aqueous and reversed micelles, vesicles and monolayers) was investigated to obtain insights into the effect of the denaturant on structured macromolecules. Direct evidence obtained from light scattering (static and dynamic), monolayer maximum isothermal compression and ionic conductivity measurements, together with indirect evidence from fluorescence photodissociation, fluorescence suppression, and thermal reactions, strongly indicates the direct interaction mechanism of urea with the aggregates. Preferential solvation of the surfactant headgroups by urea results in an increase in the monomer dissociation degree (when applied), which leads to an increase in the area per headgroup and also in the loss of counterion affinities

Effect of ventilation on systemic blood flow evaluated by echodopplercardiography

Systemic blood flow (Q) was measured by echodopplercardiography in 5 normal young adult males during apnea, eupnea and tachypnea. Measurements were made in a recumbent posture at 3-min intervals. Tachypnea was attained by doubling the respiratory frequency at eupnea at a constant tidal volume. An open glottis was maintained during apnea at the resting respiratory level. The Q values were positively correlated with the respiratory frequency, decreasing from eupnea to apnea and increasing from eupnea to tachypnea (P<0.05). These data demonstrate that echodopplercardiography, a better qualified tool for this purpose, confirms the positive and progressive effects of ventilation on systemic blood flow, as suggested by previous studies based on diverse technical approaches

Effect of hypoxia on the activity and binding of glycolytic and associated enzymes in sea scorpion tissues

The effect of hypoxia on the levels of glycogen, glucose and lactate as well as the activities and binding of glycolytic and associated enzymes to subcellular structures was studied in brain, liver and white muscle of the teleost fish, Scorpaena porcus. Hypoxia exposure decreased glucose levels in liver from 2.53 to 1.70 µmol/g wet weight and in muscle led to its increase from 3.64 to 25.1 µmol/g wet weight. Maximal activities of several enzymes in brain were increased by hypoxia: hexokinase by 23%, phosphoglucoisomerase by 47% and phosphofructokinase (PFK) by 56%. However, activities of other enzymes in brain as well as enzymes in liver and white muscle were largely unchanged or decreased during experimental hypoxia. Glycolytic enzymes in all three tissues were partitioned between soluble and particulate-bound forms. In several cases, the percentage of bound enzymes was reduced during hypoxia; bound aldolase in brain was reduced from 36.4 to 30.3% whereas glucose-6-phosphate dehydrogenase fell from 55.7 to 28.7% bound. In muscle PFK was reduced from 57.4 to 41.7% bound. Oppositely, the proportion of bound aldolase and triosephosphate isomerase increased in hypoxic muscle. Phosphoglucomutase did not appear to occur in a bound form in liver and bound phosphoglucomutase disappeared in muscle during hypoxia exposure. Anoxia exposure also led to the disappearance of bound fructose-1,6-bisphosphatase in liver, whereas a bound fraction of this enzyme appeared in white muscle of anoxic animals. The possible function of reversible binding of glycolytic enzymes to subcellular structures as a regulatory mechanism of carbohydrate metabolism is discussed.

Effect of dimethylsulfoxide on sphingomyelinase activity and cholesterol metabolism in Niemann-Pick type C fibroblasts

Niemann-Pick type C (NPC) fibroblasts present a large concentration of cholesterol in their cytoplasm due to a still unidentified deficiency in cholesterol metabolism. The influence of dimethylsulfoxide (DMSO) on the amount of intracellular cholesterol was measured in 8 cultures of normal fibroblasts and in 7 fibroblast cultures from NPC patients. DMSO was added to the fibroblast cultures at three different concentrations (1, 2 and 4%, v/v) and the cultures were incubated for 24 h. Sphingomyelinase activity was significantly increased in both groups of cells only when incubated with 2% DMSO (59.4 ± 9.1 and 77.0 ± 9.1 nmol h-1 mg protein-1, controls without and with 2% DMSO, respectively; 47.7 ± 5.2 and 55.8 ± 4.1 nmol h-1 mg protein-1, NPC without and with 2% DMSO, respectively). However, none of the DMSO concentrations used altered the amount of cholesterol in the cytoplasm of NPC cells (0.704 ± 0.049, 0.659 ± 0.041, 0.688 ± 0.063 and 0.733 ± 0.088 mg/mg protein, without DMSO, 1% DMSO, 2% DMSO and 4% DMSO, respectively). This finding suggests that sphingomyelinase deficiency is a secondary defect in NPC and shows that DMSO failed to remove the stored cholesterol. These data do not support the use of DMSO in the treatment of NPC patients.

Effect of thyroparathyroidectomy on urinary acidification in diabetic rats

In previous studies we have shown stimulation of renal acid excretion in the proximal tubules of rats with diabetes of short duration, with no important alterations in glomerular hemodynamics; on the other hand, in thyroparathyroidectomized rats (TPTX model), a significant decrease in renal acid excretion, glomerular filtration rate (GFR) and renal plasma flow (RPF) was detected. Since important changes in the parathyroid hormone-vitamin D-Ca axis are observed in the diabetic state, the present study was undertaken to investigate the renal repercussions of thyroparathyroidectomy in rats previously made diabetic by streptozotocin (45 mg/kg). Four to 6 days after the induction of diabetes (DM), a group of rats were thyroparathyroidectomized (DM + TPTX). Renal functional parameters were evaluated by measuring the inulin and sodium para-aminohippurate clearance on the tenth day. The decrease in the GFR and RPF observed in TPTX was not reversed by diabetes since the same alterations were observed in DM + TPTX. Net acid (NA) excretion was unchanged in DM (6.19 ± 0.54), decreased in TPTX (3.76 ± 0.25) and returned to normal levels in DM + TPTX (5.54 ± 0.72) when compared to the control group (6.34 ± 0.14 µmol min-1 kg-1). The results suggest that PTH plays an important vasodilator role regarding glomerular hemodynamics, since in its absence the impairment in GFR and RPF was not reversed by the diabetic state. However, with respect to acid excretion, the presence of diabetes was able to overcome the negative stimulus represented by TPTX.