Chemical composition and repellent activity of essential oils from the leaves of Cinnamomum zeylanicum and Eugenia uniflora against Diaphania hyalinata L. (Lepidoptera: Crambidae)

Journal of Plant Diseases and Protection - Diaphania hyalinata is an important pest in organic melon crops and has caused considerable harm to growers in northeastern Brazil. The aim of the present...     

Exposure to 17α,20β-dihydroxy-4-pregnen-3-one changes seminal characteristics in Nile tilapia, Oreochromis niloticus

This experiment was conducted to evaluate the seminal characteristics of Nile tilapia males exposed to water‐borne 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20βP). Male Nile tilapia (Oreochromis niloticus L.) were exposed to the steroidal pre‐ovulatory pheromone 17,20βP, added to water at a concentration of 5×10^?9 M. The pheromone‐exposed males had higher sperm volume and concentration. In addition, the spermatozoa contained in the sperm had higher motility and the motility duration was longer than ethanol‐exposed males (control group). The percentage of live spermatozoa was not affected by the treatments. Our results suggest that this pheromone can improve sperm quality characteristics and could become a non‐invasive method for enhancing spawning in Nile tilapia.     

Detecting the attack of the fall armyworm (Spodoptera frugiperda) in cotton plants with machine learning and spectral measurements

Precision Agriculture - The Spodoptera frugiperda (i.e., fall armyworm) causes irreversible damage in cotton cultivars, and its visual inspection on plants is a burdensome task for humans. A recent...     

Biochemical and histological responses of Rattus novergicus (Wistar) infected by Echinostoma paraensei (Trematoda: Echinostomatidae)

Tests were performed to evaluate the biochemical alterations in Rattus norvegicus after infection by the intestinal trematode Echinostoma paraensei. The rodents received 150 metacercariae each, serum samples were collected and the parasite load was quantified weekly until the fifth week of infection. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALKP), gamma-glutamyl transferase (GGT), bilirubin, glucose, total proteins and fractions and hepatic glycogen were determined. All the animals exposed to the metacercariae were infected in the first week and worms were recovered up to the third week after infection. The levels of AST, ALT, GGT, bilirubin and globulin rose in the first and/or second week and declined thereafter to levels near those of the control group. In contrast, the level of total proteins in the plasma fell significantly in the first week while the ALKP activity went down only in the fourth and fifth weeks in relation to the control group. There was no significant difference in the levels of albumin, glycogen and glucose. Infection by E. paraensei in R. norvegicus causes changes in the hepatic function, possibly resulting from the cholestasis produced by the partial obstruction of the bile duct by the helminths.     

Genetic diversity of Brazilian farmers-made strawberry genotypes and their relationship with commercial cultivars

Genetic Resources and Crop Evolution - The cultivated strawberry [Fragaria × ananassa (Duchesne ex Weston) Duchesne ex Rozier] is one of the most valuable small fruits worldwide....     

Astroglial cells in primary culture: a valid model to study Neospora caninum infection in the CNS

The protozoan Neospora caninum has a veterinary importance because it causes abortion in cattle and neuromuscular alterations in dogs. We infected rat astrocytes, in vitro, with different concentrations of N. caninum. Astrocytes responded to infection by producing the pro-inflammatory cytokine TNF-alpha and the neurotoxic-free radical NO, 24 and 72 h post-infection. These data suggest that astrocytes, which are essential for brain function, are targets for the parasite and this represents a practical and valid model to study the effects of N. caninum on the CNS.     

Genetic variation of germination cold tolerance in Japanese rice germplasm

Low temperatures at the initial stages of rice development prevent fast germination and seedling establishment and may cause significant productivity losses. In order to develop rice cultivars exhibiting cold tolerance, it is necessary to investigate genetic resources, providing basic knowledge to allow the introduction of genes involved in low temperature germination ability from accessions into elite cultivars. Japanese rice accessions were evaluated at the germination under two conditions: 13°C for 28 days (cold stress) and 28°C for seven days (optimal temperature). The traits studied were coleoptile and radicle length under optimal temperature, coleoptile and radicle length under cold and percentage of the reduction in coleptile and radicle length due to low temperature. Among the accessions studied, genetic variation for traits related to germination under low temperatures was observed and accessions exhibiting adequate performance for all investigated traits were identified. The use of multivariate analysis allowed the identification of the genotypes displaying cold tolerance by smaller reductions in coleoptile and radicle lenght in the presence of cold and high vigour, by higher coleoptile and radicle growth under cold.     

Influence of umbrella pine (<Emphasis Type="Italic">Pinus</Emphasis><Emphasis Type="Italic">pinea</Emphasis> L.) stand type and tree characteristics on cone production

Most umbrella pine (Pinus pinea L.) stands are managed as agroforestry systems, whose main production is fruit, due to the edible and highly nutritious kernels, and are frequently associated to natural or seeded pastures and grazing. The stands have low density, in order to enhance crown growth and fruit production. Nevertheless, cone production, both with regard to number and weight, varies greatly between stands, trees and years. In this study were selected three agroforestry systems, representative of umbrella pine stands whose main production is fruit, and one stand representative of the timber production system, where fruit is the secondary production. It was evaluated the variability in cone production as a function of the tree’s diameter at breast height and crown diameter and the individual tree’s competition status. The results indicate that stands managed in agroforestry systems with lower competition and individuals with larger diameter at breast height and crown diameter tend to produce more and heavier cones per tree. The first two principal components of the principal component analysis explain 84 % of the variance in cone production, trees’ dimensions and competition index. Tree competition status has a negative impact on production per tree.