Effect of Bovine Ovarian Tissue Vitrification on the Structural Preservation of Antral Follicles

This study was performed to evaluate the structural preservation of antral follicles after bovine ovarian tissue vitrification using histological analysis. Ovaries (n = 30) of slaughtered cows were cut into small fragments using a scalpel blade, and the ovarian tissues were randomly assigned to vitrification using 15% dimethyl sulphoxide (DMSO) and 15% ethylene glycol (EG) and fresh tissues (control) groups. For histological evaluations, fresh and post‐thawing ovarian tissues were immediately fixed, serially sectioned into 5‐μm sections and stained with haematoxylin and eosin (H&E). Nine serial sections per fragment were subjected for morphological assessment. The diameter of the antral follicles was determined and classified into four groups: 1 (≤1 mm), 2 (>1–2 mm), 3 (>2–3 mm) and 4 (>3–4 mm). Then, follicular morphology was evaluated in relation to atresia and categorized into seven grades: Grade A (healthy follicle); Grades B, C and D (early atresia); Grades E and F (moderate atresia); and Grade G (advanced atresia). The results revealed that small diameters of antral follicles (1 and 2 mm) were more susceptible for cryoinjury. The normal follicular morphology (Grade A) was not affected by vitrification throughout follicle diameters. Nevertheless, some damage features were monitored after vitrification. In conclusion, the morphological structure of bovine antral follicles could be successfully preserved by ovarian tissue vitrification.     

Using graph theory to analyse and assess changes in Mediterranean woodland connectivity

Landscape Ecology - The Portuguese montado is an agro-silvopastoral system, similar to the Spanish dehesa, known for its cultural, economic and ecological value. Despite its importance, contrasting...     

Effect of Oestrous Cycle on the Oxidative Burst Activity of Blood Polymorphonuclear Leucocytes in Cows

Blood polymorphonuclear leucocyte (PMN) oxidative burst activity, plasma cortisol levels, and the total and differential white blood cells counts (WBC) of six cycled dairy cows were evaluated for a period of 24 days, three times a week; on Mondays, Wednesdays and Fridays. The PMN oxidative burst was indirectly evaluated by flow cytometry, measuring the intracellular oxidation of 2′,7′‐dichlorofluorescein diacetate to 2′,7′ dichlorofluorescein (DCF) by H₂O₂‐production. Results are pre‐sented as the mean fluorescence intensity (MFI) of DCF. Cow’s oestrous cycle was evaluated by following the plasma progesterone levels using a radioimmunoassay method. Levels of cortisol in the plasma were measured using a fluorimetric method. The oxidative burst activity of PMN, represented a maximum value (MFI = 117.6 ± 7.4) during the oestrous period. A fall was then observed, in which a steady state was observed during the lutheinic phase of the oestrous cycle, reaching the minimum value [MFI = 73.2 ± 11.2 (p ≤ 0.01)] on the days +8, +9 and +10. No significant variations were observed in the levels of cortisol, or in total and differential WBC, during the whole period. Nevertheless, as far as cortisol levels were concerned, a trend analogous to that of the oxidative burst activity was observed. Our results demonstrated that the oestrous cycle might influence directly, or indirectly, the immune system of cows, by altering the oxidative burst of PMN.     

Novel application of square-wave adsorptive-stripping voltammetry for the determination of xanthohumol in spent hops

This paper reports the development of a novel electrochemical assay for xanthohumol (XN) by square-wave adsorptive-stripping voltammetry (SWAdSV) with a hanging mercury drop electrode. The method showed good repeatability (CV < 2%) and linearity (between 10 and 250 μg L(-1)), as well as suitable limits of detection (2.6 μg L(-1)) and quantification (8.8 μg L(-1)). The method was applied for the quantification of this compound in spent hops, and the results obtained were compared with the HPLC-UV method. XN contents determined by the SWAdSV method were 16 ± 1 and 100 ± 4 μg L(-1) for aqueous and methanolic extracts, respectively. The developed new methodology considerably reduces the analysis time, approximately from 25 min (HPLC-UV method) to 7 min, enabling a high sample throughput. In addition, the detection and quantification limits were approximately 5-fold lower than those obtained with the chromatographic method.     

Microtomographic characterization of calcifications in canine mammary tumours

The present work describes the microtomographic characterization of macro‐ and microcalcifications present in excised canine mammary glands. In human breast cancer, microcalcifications are highly relevant for diagnosis and prognosis, often being the sole element determining biopsy. Canine mammary tumours are considered a model for human breast cancer, but the morphological features of calcifications had still to be studied in this species. The objective of this research is to contribute to the characterization of the mineralization features of the canine mammary gland. In the present study, the excised mammary glands of 33 bitches underwent fluoroscopic examination. In 30 of the samples, the presence of calcification was suspected, and multiple biopsies were taken of these areas. Biopsy fragments underwent microtomographic scanning. Microcalcifications were found in non‐neoplastic glandular tissue, benign and malign lesions, as it is known to happen in humans. Qualitative evaluation regarding morphology of the imaged calcifications showed similarities to breast cancer findings, based on the BI‐RADS 2013 classification, such as pleomorphism and shape. No differences in the quantitative morphological parameters of volume, surface, surface/volume, SMI and structure thickness were found when macrocalcifications were considered. However, although significant differences existed in these parameters between microcalcifications from malignant canine mammary tumours and the two other groups, none were found between non‐neoplastic and benign tumours. Findings further support the use of this spontaneous animal model for the study of human breast cancer, considering how clinically relevant microcalcifications are in humans.     

Characterization of extraintestinal Escherichia coli isolated from a peacock (Pavo cristatus) with colisepticemia

Extraintestinal infections by avian pathogenic strains of Escherichia coli (APEC) are commonly reported in poultry, but there is little information on infections by APEC in other bird species. Here we report on the characterization of extraintestinal E. coli isolated from a domesticated peacock, from the south of Brazil, that died of colisepticemia. Necropsy examination revealed congested liver, hypertrophied kidneys, peritonitis, severe typhlitis suggestive of coligranuloma, pneumonia, and airsacculitis--typical signs of colisepticemia. The isolates from lungs, kidney, heart, intestine, liver, and bone marrow all harbored the same virulence-associated factors (iucD, colV, iss, mat, fimC, ompA, traT crl, csgA vgrG, and hcp), yielded the same band pattern in amplified ribosomal DNA restriction analysis, and were allocated to the Escherichia coli Reference Collection group B1. The isolates were resistant to bacitracin, trimethoprim, and tetracycline, but displayed slight differences in their resistance to other antimicrobials. The isolates also differed in their virulence in 1-day-old chickens, but none displayed high virulence in vivo. We conclude that the peacock died of colisepticemia after it was infected with an extraintestinal E. coli strain of low virulence that nevertheless harbored virulence factors generally associated with APEC. This study represents the first characterization of an APEC isolated from a nonpoultry bird species.     

Nitrogen mineralization in sandy loam soils under an intensive double-cropping forage system with dairy-cattle slurry applications

Nitrogen (N) mineralization and soil mineral N contents were measured at 2-week intervals over a 2-year period (June 1994–May 1996) on two different sites in the North West region of Portugal. The experiment was established in fields, which had for many years been under a double-cropping forage system with maize from May to September and a winter crop (mixture of cereals and Italian ryegrass) during the rest of the year. In addition to N fertilizers, dairy-cattle slurry was applied regularly at the sowing of each crop. On this intensive forage system, quantification of N released from slurry, crop residues and soil organic matter becomes important when better N use efficiency and reduced environmental impact from agricultural practices are required. Net N mineralization rates of the 0–10 cm soil layer fluctuated considerably between consecutive incubation periods and ranged from −0.88 to 1.87 mg N kg⁻¹ day⁻¹ with annual average rates of between 0.41 and 0.65 mg N kg⁻¹ day⁻¹. The total N mineralized in the 10 cm depth soil layer reached values between 122 and 224 kg N ha⁻¹ year⁻¹, showing that mineralization was a very important N source for the crops. The amounts of N released during the cold season (November–February) were equivalent to 27–48% of the yearly total. Regression analysis indicated that seasonal variation in N mineralization was only poorly explained by soil moisture and temperature. The changing balance during the year between soil moisture and temperature will contribute to the relatively constant N mineralization rates. Soil mineral N contents during the maize crop were high and exceeded the nutrient requirements for the optimum yield of this crop. Under the climatic conditions of the region and due to the poor development of the winter crop plants at the time, the mineral N left in the soil after the maize crop and released by mineralization during the cold season is particularly vulnerable to nitrate leaching losses.     

A new insight into the influence of habitat on the biochemical properties of three commercial sea cucumber species

International Aquatic Research - This work makes a comparative evaluation of the biochemical profile of three sea commercial cucumber species (Holothuria mammata, H. polii and H. tubulosa) caught...     

Infection process of <Emphasis Type="Italic">Pseudocercospora musae</Emphasis> on banana leaf

Yellow Sigatoka that is caused by Pseudocercospora musae is an important banana disease. The aim of this study was to elucidate the infection process of P. musae in banana leaves by scanning electron microscopy. Leaf samples were inoculated on the abaxial surface with P. musae and then analysed at 12, 24, 36, 48, 72, 96, 120, 144, and 168 h post inoculation (hpi) and at 36 and 50 days post inoculation (dpi). The conidia were found to be germinated between 24 and 36 hpi and penetrated through the stomata between 96 and 120 hpi, or more generally from 144 hpi. P. musae colonized the spongy parenchyma at 36 dpi and the palisade parenchyma at 50 dpi. Sporulation occurred at 50 dpi on the adaxial surface of leaves through the emergence of conidia on conidiophores through the stomata. Considering the importance of yellow Sigatoka in banana production, our results provide a better understanding of the life cycle of the fungus for treatment processes.