Anti‐Mullerian Hormone Concentration and Antral Ovarian Follicle Population in Murrah Heifers Compared to Holstein and Gyr Kept Under the Same Management

This study was performed to evaluate plasma concentrations of anti‐Mullerian hormone (AMH) and the ovarian antral follicle population (AFP) in different genetic groups. Cyclic heifers (13 Bubalus bubalis [Murrah]; 15 Bos taurus [Holstein] and 10 Bos indicus [Gyr]) were maintained under the same management and were synchronized with two doses of 150 μg IM d‐cloprostenol administered 14 days apart. After the second d‐cloprostenol treatment, heifers had their ovaries scanned daily by ultrasound to define the day of ovulation. On the same day, the AFP was determined and a plasma sample was collected to measure AMH. Murrah heifers had less AFP (25.6 ± 2.1 follicles; p = 0.01) and plasma AMH concentration (0.18 ± 0.03 ng/ml; p < 0.001) than Gyr (60.0 ± 12.2 follicles and 0.60 ± 0.12 ng/ml of AMH); however, data were similar when compared to Holstein (35.9 ± 6.8 follicles and 0.24 ± 0.06 ng/ml of AMH) heifers. Regardless of genetic background, there was a positive relationship between the AFP and plasmatic AMH concentration (Murrah [r = 0.62; p < 0.01], Holstein [r = 0.66; p < 0.001] and Gyr [r = 0.88; p < 0.001]). Also, when heifers were classified according to high‐ or low‐AMH concentration based on the average within each genetic group, high‐AMH heifers had greater (p < 0.0001) AFP than low‐AMH heifers. In conclusion, both Murrah and Holstein heifers presented lower plasma AMH concentration and AFP when compared to Gyr.     

Serum vitamin D,calcium, and phosphorus concentrations in ponies,horses and foals from the United States and Thailand

Vitamin D is essential in calcium and phosphorus regulation, bone physiology, cell proliferation and epithelial integrity. Literature on vitamin D in growing horses is sparse, and the effect of age on vitamin D has not been evaluated in equids in the United States or in tropical countries. The goal of this study was to determine if there was an effect of age on serum 25(OH)D₃ concentrations in equids in the US (Ohio/Kentucky) and Thailand (Chiang Rai and Kanchanaburi) during the same time of the year. Blood samples were collected from healthy ponies (n = 21) and Thoroughbred foals (n = 13), yearlings (n = 10), and horses (n = 20) in Thailand and from Thoroughbred foals (n = 10) and horses (n = 17) in the US. Serum concentrations of 25(OH)D₃, calcium and phosphorus were measured.In both countries, serum 25(OH)D₃ concentrations were lower in foals than in yearlings and adult horses. Serum 25(OH)D₃ concentrations were higher in horses than in ponies in Thailand, but were not different between horses from either country. Calcium concentrations were not different between groups or location. In both countries, phosphorus concentrations were higher in foals than in older groups; however, were not different between ponies and horses. This study shows that independent of geography there are age-related differences in 25(OH)D₃ concentrations in horses and further confirms that 25(OH)D₃ concentrations are lower in horses compared to other species. The information will serve as the basis for future clinical studies and to help understand better the pathophysiology of equine disorders associated with calcium and phosphorus dysregulation.     

Role of NMDA receptor subtypes in governing the direction of hippocampal synaptic plasticity

Activation of N-methyl-d-aspartate subtype glutamate receptors (NMDARs) is required for long-term potentiation (LTP) and long-term depression (LTD) of excitatory synaptic transmission at hippocampal CA1 synapses, the proposed cellular substrates of learning and memory. However, little is known about how activation of NMDARs leads to these two opposing forms of synaptic plasticity. Using hippocampal slice preparations, we showed that selectively blocking NMDARs that contain the NR2B subunit abolishes the induction of LTD but not LTP. In contrast, preferential inhibition of NR2A-containing NMDARs prevents the induction of LTP without affecting LTD production. These results demonstrate that distinct NMDAR subunits are critical factors that determine the polarity of synaptic plasticity.     

Multispectral radiometric monitoring of bacterial blight of coffee

Precision Agriculture - Bacterial blight of coffee caused by Pseudomonas syringae pv. garcae shows great destructive potential in the main coffee producing regions in Brazil and worldwide. Remote...     

Effects of selenium supplementation on the oxidative state of acute heat stress‐exposed quails

This study aimed to evaluate the effect of heat stress (HS) and selenium supplementation on markers of stress, meat quality and gene expression. For this, meat quails of 42 days of age were fed a diet that either met [0.33 mg/kg, nutritional demand for selenium (SS)] or did not meet [0.11 mg/kg, selenium deficient (SD)] the nutritional demands for selenium during the 7 days of evaluation. In addition, the animals were kept at either a thermal comfort temperature (25 °C) or exposed to HS (38 °C for 24 h). Glutathione synthetase (GSS), glutathione reductase (GSR) and uncoupling protein (UCP) gene expression were influenced by the interaction between temperature and diet. Animals subjected to HS and fed the SS diet exhibited the highest GSS and GSR gene expression. In terms of UCP gene expression, the lowest values were observed in HS animals on the SD diet. Glutathione peroxidase 7 (GPX7) gene expression, body temperature (BT) and creatine kinase (CK) activity were influenced by both selenium supplementation and HS. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) activity and creatinine content all were influenced by the diet/environment interaction. The highest AST activity, ALT activity and creatinine levels were observed in animals that were both on the SD diet and exposed to HS. HS animals also exhibited an increased heterophil/lymphocyte ratio and lower triiodothyronine (T3) hormone levels than birds that remained at the comfortable temperature. Animals subjected to HS and fed with selenium supplemented diet showed better results regarding gene expression and, thus, better results for the activities of enzymes used as stress markers, which could be due to the higher antioxidant capacity provided by the action of the studied genes.     

Effect of Different Combinations of Cryoprotectants on In Vitro Maturation of Immature Buffalo (Bubalus bubalis) Oocytes Vitrified by Straw and Open‐Pulled Straw Methods

This study was designed to evaluate effects of different combinations of cryoprotectants on the ability of vitrified immature buffalo oocytes to undergo in vitro maturation. Straw and open‐pulled straw (OPS) methods for vitrification of oocytes at the germinal vesicle stage also were compared. The immature oocytes were harvested from ovaries of slaughtered animals and were divided into three groups: (i) untreated (control); (ii) exposed to cryoprotectant agents (CPAs); or (iii) cryopreserved by straw and OPS vitrification methods. The vitrification solution (VS) consisted of 6 m ethylene glycol (EG) as the standard, control vitrification treatment, and this was compared with 3 m EG + 3 m dimethyl sulfoxide (DMSO), 3 m EG + 3 m glycerol, and 3 m DMSO + 3 m glycerol. Cryoprotectants were added in two steps, with the first step concentration half that of the second (and final) step concentration. After warming, oocyte samples were matured by standard methods and then fixed and stained for nuclear evaluation. Rates of MII oocytes exposed to CPAs without vitrification were lower (54.3 ± 1.9% in EG, 47.5 ± 3.4% in EG + DMSO, 36.8 ± 1.2% in EG + glycerol and 29.9 ± 1.0% in DMSO + glycerol; p < 0.05) than for the control group (79.8 ± 1.3%). For all treatments in each vitrification experiment, results were nearly identical for straws and OPS, so all results presented are the average of these two containers. The percentages of oocytes reaching telophase‐I or metaphase‐II stages were lower in oocytes cryopreserved using all treatments when compared with control. However, among the vitrified oocytes, the highest maturation rate was seen in oocytes vitrified in EG + DMSO (41.5 ± 0.6%). Oocytes cryopreserved in all groups with glycerol had an overall low maturation rate 19.0 ± 0.6% for EG + glycerol and 17.0 ± 1.1% for DMSO + glycerol. We conclude that the function of oocytes was severely affected by both vitrification and exposure to cryoprotectants without vitrification; the best combination of cryoprotectants was EG + DMSO for vitrification of immature buffalo oocytes using either straw or OPS methods.     

Tunneling into a single magnetic atom: spectroscopic evidence of the kondo resonance

The Kondo effect arises from the quantum mechanical interplay between the electrons of a host metal and a magnetic impurity and is predicted to result in local charge and spin variations around the magnetic impurity. A cryogenic scanning tunneling microscope was used to spatially resolve the electronic properties of individual magnetic atoms displaying the Kondo effect. Spectroscopic measurements performed on individual cobalt atoms on the surface of gold show an energetically narrow feature that is identified as the Kondo resonance-the predicted response of a Kondo impurity. Unexpected structure in the Kondo resonance is shown to arise from quantum mechanical interference between the d orbital and conduction electron channels for an electron tunneling into a magnetic atom in a metallic host.     

Modelling black Sigatoka epidemics with seasonal dispersal of Mycosphaerella fijiensis ascospores over a banana plantation in the Ribeira Valley,São Paulo,Brazil

Knowing the patterns of Black Sigatoka development is essential to propose adequate disease management practices and evaluate their effects, which can be achieved through temporal analysis by integrating the evolving interactions of the pathosystem components, expressed by data on cumulative incidence and severity, and summarizing these data in a disease progress curve. Airborne spores are essential components for the progression of an epidemic in the context of a specific pathosystem. In this perspective, the spore count is an essential approach to assess and model an epidemic. This study evaluated the temporal dynamics of Black Sigatoka in a banana plantation in the Ribeira Valley, state of São Paulo, Brazil, while simultaneously performing a year-long evaluation of fungal spore aerobiology. The disease was intense during the rainy season, but the leaf emergence rate was high enough for quickly inverting the severity peak (between 169 and 197 days of evaluation). After that, the disease severity raised until reach the higher rates (around the score 7 out of 8). The disease progress curve of Black Sigatoka showed peaks of extreme severity, one in the rainy and another in the dry season, with high levels of ascospores in the air. The ascospore concentration and the severity of the disease correlated significantly on the same day of sampling and 15 days after ascospore sampling, corresponding to the average latency period of the disease in the region. The patterns of the disease progress curve in both peaks fitted the monomolecular model, with higher rates of disease increase in the rainy season.

     

Geostatistical analysis of the spatial variation of the berry borer and leaf miner in a coffee agroecosystem

The advent of geostatistics and geographical information systems has made it possible to analyze complex spatial patterns of ecological phenomena over large areas in applied insect ecology and pest management. The objective of this study was to use geostatistics to characterize the spatial structure and map the spatial variation of damage caused by the berry borer (Hypothenemus hampei) and leaf miner (Leucoptera coffeella) in a coffee agroecosystem planted with the cultivar Catuai Vermelho IAC-99. Infestations of berry borer and leaf miner were evaluated in fruits and leaves, respectively. The pests were monitored at 67 georeferenced points in an area of 6.6 ha in 2005, 2006 and 2007. Variograms estimated by the method of moments (MoM) and residual maximum likelihood REML were compared. The latter were generally better in terms of the kriging error coefficients. Spherical variograms estimated by REML for berry borer infestation in fruits had ranges of spatial dependence of 34.62–118.4 m and for the leaf miner they were 53.93–133.7 m. For models fitted by weighted ordinary least squares (OLS) to the MoM experimental variogram, the ranges varied between 37.22 and 68.67 m for the berry borer and 100 and 155.4 m for leaf miner infestation. The variogram model parameters were used with the data for ordinary kriging to map the spatial variation of coffee pests for different monitoring periods. If there was no suitable variogram, inverse distance weighting was used to map the variation. The maps enabled visualization of the intensity of infestation of the insect pests for the different periods evaluated.