Occurrence of two forms of Y chromosome in rainbow trout (Oncorhynchus mykiss) males from Rutki strain

Morphologically differentiated sex chromosomes are found in only few salmonid species. Some populations of rainbow trout, Oncorhynchus mykiss, exhibit chromosomal polymorphism related to sex. We found sex-related chromosomal polymorphism in fish from the synthetic Rutki strain, Poland, in approximately 85% (n = 22) of examined males (XY-like) whereas the remaining males (n = 4) possessed chromosomes similar to these observed in females (XX-like). To investigate whether males possessing XX-like chromosomes were genotypic males or genotypic females with altered phenotypic sex, androgenetic progeny of four males (representing both XY-like and XX-like forms, n = 2 + 2) was examined. Androgenetic progeny (F₁) of all four fathers consisted of both phenotypic females and males. F₁ male progeny of two fathers showed XX-like chromosomes whereas F₁ male progeny of the other two fathers possessed YY-like (supermale) chromosomes. F₁ were reared further until they were sexually mature. Two males from each of four F₁ families were used to produce F₂ androgenetic and control F₂ generation. All F₂ individuals, androgenetics and control, were phenotypic males at sexual maturation. The results indicate that males possessing XX-like chromosomes are genetic males and they are not sex-reversed females. Thus, the Y chromosome can exist in different morphological forms in farmed rainbow trout. The Y^S chromosome (shorter form, unlike the X chromosome) has a shorter or absent p-arm and lacks the pericentromeric cluster of AT-rich chromatin and the 5S rDNA sequences that are found in the Y^L chromosome (longer form, like the X chromosome).     

DOUBLE CONTRAST GASTROGRAPHY IN THE NORMAL DOG

Double contrast gastrography affords more accurate detection of gastric lesions because it allows direct evaluation of mucosal pattern contours. The technic involves the induction of gastric hypomotility with intravenous glucagon, gastric intubation for the introduction of air and high-density barium directly into the stomach, and positional manipulation for maximal air-barium interface demonstration. Some dogs require sedation. Although fluoroscopic observation is an asset in isolating gastric anatomic abnormalities, this study may be performed using conventional radiographic equipment without fluoroscopic guidance. Double contrast gastrography is used to demonstrate the stomach mucosal surface by coating it with high-density barium and having the mucosa contrast with the air-filled gastric lumen. There are three elements to each double contrast image: the dependent surface, the nondependent surface, and the barium pool. The barium pool is manipulated to coat the mucosal surface and fill depressions of the dependent surface. Protrusions of the dependent surface appear as radiolucencies in the barium pool. Depressions and protrusions of the nondependent surface are outlined by barium. Double contrast gastrography is indicated in dogs where clinical signs suggest anatomic changes in the gastric mucosal surface, e.g., neoplasms, ulcers, or polyps. Concurrent gastrointestinal motility evaluation is precluded by sedation and the glucagon-induced gastric hypomotility.     

Soybean expansion impacts on soil organic matter in the eastern region of the Maranhão State (Northeastern Brazil)

Recently, the eastern region of the Maranhão state (Northeastern Brazil) became a hotspot of land-use change (LUC) directly from native vegetation to soybean cultivation, but due to the soil characteristics, LUC has caused substantial soil organic carbon (SOC) and nitrogen depletion. Therefore, we quantified these impacts arising from two factors: (i) different timeframes after LUC and (ii) contrasting soil management practices. For the first study, soil samples (0–30 cm; six replicates) were taken on soybean fields year one, year eight and 15 years after LUC. It the second study, another area was sampled, of which part was managed under no-tillage (NT) and the other using a mouldboard plough (MP). For both studies, native vegetation (NV) was sampled as the control. NV stored about 50 Mg of carbon (C) ha⁻¹; but LUC reduced C stocks by 35% (after 8 and 15 years); moreover, labile-C decreased between 20% and 45%, while, microbial-C decreased between 20% and 60%, considering the interval between year one and 15 years. Regarding soil management, the MP did not cause differences on C stock (24 Mg C ha⁻¹) in comparison to NT; however, both labile-C and microbial-C decreased by 15% to NT, while, decreased by 40% to MP. These results lead us to believe that, since LUC is inevitable, we suggested the adoption of the best agricultural management practices, in order to preserve/increase the SOC, reducing the impacts on GHG emissions and, thus, achieving sustainability and profitability.     

Effect of water deficit on morphoagronomic traits of black common bean genotypes (Phaseolus vulgaris L.) with contrasting drought tolerance

Brazil is the world's largest producer of common beans (Phaseolus vulgaris L.). Drought stress harms the morphological and agronomic traits of beans. This study evaluates the reaction to water deficit in five genotypes of black beans. The experiment was conducted in the IDR-IAPAR-EMATER in Londrina-PR, Brazil. A split-plot design was used, with three replications. The genotypes were included in the subplots and the treatments with or without water deficit in the plots. Water deficit was induced on the pre-flowering stage and maintained for 20 days in the plots submitted to drought stress. For the growth analysis, plants were collected at 35, 54 and 70 days after emergence. At the stage of physiological ripeness, several morphological and yield traits were evaluated. The genotypes IPR Uirapuru and BRS Esplendor can be considered tolerant and used as a tolerant source to water deficit in common bean germplasm banks. The line LP 08-90 has morphological and agronomic adaptations efficient to overcome water deficit's effects, presenting a higher grain yield in both crop conditions, which indicates the success of black beans breeding to deal with water deficit.     

Protected areas and native freshwater bivalves are not in the same place in south-east Brazil

1. Bivalves are important components of freshwater ecosystems; however, they are also one of the most threatened animal groups, especially members of the order Unionida. The main threats to freshwater bivalves are habitat modification and invasive species. Protected areas are a common way to minimize impacts and preserve native species, but they are rarely designated with a focus on freshwater invertebrates.
2. The main goal of this article was to describe the distribution of freshwater bivalves in the state of Rio de Janeiro, and the relationship between these species and bioclimatic areas, land use and protected areas.
3. Five native and two invasive bivalve species have been reported in Rio de Janeiro. They occur mainly in bioclimatic areas related to the Paraíba do Sul River and Campista Lowlands. The few records of bivalves inside protected areas are in areas of sustainable use that offer a lower level of protection, and frequently in sympatry with invasive bivalves.
4. Thus, the established protected areas in Rio de Janeiro are not adequately effective for freshwater bivalve conservation, and some species remain under threat even within them. Freshwater bivalves thus remain largely unprotected in the state.
5. The development of new protected areas and management plans should consider other faunal groups that are usually ignored, such as freshwater bivalves, to achieve more inclusive and effective protection.