Far from urban areas: plastic uptake in fish populations of subtropical headwater streams.

This study investigated the occurrence of plastic particles in the digestive tracts of fish from headwater streams in a human-thinly populated region of the subtropical Sinos River basin in southern Brazil. In total, 258 individuals from 17 species were collected using electric fishing. Thirty-eight percent (38%) of the specimens contained plastic particles. All of them were fibers, with a maximum count of 43 per individual. Plastic fibers were the fourth most abundant food category. Results showed that the uptake of these plastic particles was proportional to the number of ingested food items. Fiber counts in the guts correlated with the uptake of Trichoptera, which are invertebrates using plastic particles to construct their protective cases. No significant difference in plastic uptake was detected between benthic and water column fish. No evidence of bioaccumulation of plastic particles was found in the intestines. The distance from urban areas was not related to the number of ingested plastic particles, concluding that plastics are ubiquitous and available to biota, even in remote locations. The most probable source of these particles is residences close to the streams which discharge the sewage of washing machines without any treatment.

Far from urban areas: plastic uptake in fish populations of subtropical headwater streams / Longe das áreas urbanas: ingestão de plástico em populações de peixes de riachos subtropicais de cabeceira

This study investigated the occurrence of plastic particles in the digestive tracts of fish from headwater streams in a human-thinly populated region of the subtropical Sinos River basin in southern Brazil. In total, 258 individuals from 17 species were collected using electric fishing. Thirty-eight percent (38%) of the specimens contained plastic particles. All of them were fibers, with a maximum count of 43 per individual. Plastic fibers were the fourth most abundant food category. Results showed that the uptake of these plastic particles was proportional to the number of ingested food items. Fiber counts in the guts correlated with the uptake of Trichoptera, which are invertebrates using plastic particles to construct their protective cases. No significant difference in plastic uptake was detected between benthic and water column fish. No evidence of bioaccumulation of plastic particles was found in the intestines. The distance from urban areas was not related to the number of ingested plastic particles, concluding that plastics are ubiquitous and available to biota, even in remote locations. The most probable source of these particles is residences close to the streams which discharge the sewage of washing machines without any treatment.

Este estudo investigou a ocorrência de partículas plásticas no trato digestivo de peixes de riachos de cabeceira em uma região de baixa densidade humana da bacia subtropical do rio dos Sinos no sul do Brasil. No total, 258 indivíduos de 17 espécies foram coletados por meio da pesca elétrica. Trinta e oito por cento (38%) dos espécimes continham partículas de plástico. Todos eram fibras, com contagem máxima de 43 por indivíduo. As fibras plásticas foram a quarta categoria de alimentos mais abundante. Os resultados mostraram que a absorção dessas partículas plásticas foi proporcional ao número de itens alimentares ingeridos. A contagem de fibras nos intestinos se correlacionou com a absorção de Trichoptera, que são invertebrados que usam partículas de plástico para construir suas capas protetoras. Nenhuma diferença significativa na absorção de plástico foi detectada entre peixes bentônicos e de coluna d'água. Nenhuma evidência de bioacumulação de partículas plásticas foi encontrada nos intestinos. A distância das áreas urbanas não foi relacionada ao número de partículas plásticas ingeridas, concluindo que os plásticos são ubíquos e disponíveis para a biota, mesmo em locais remotos. A fonte mais provável dessas partículas são as residências próximas aos córregos que descarregam os esgotos das máquinas de lavar sem nenhum tratamento.

First record of pughead deformity in Cichla kelberi (Teleostei: Cichlidae), an invasive species in an estuarine system in south-eastern Brazil.

The first record of pughead deformity in a Neotropical freshwater fish not raised in captivity is provided, based on an adult male of Cichla kelberi introduced into an estuary of Rio de Janeiro State, south-eastern Brazil. A general biological characterization of the specimen is provided and aspects of its aberrant anatomy are described. Environmental and biological factors that may cause pughead deformity in fishes are discussed.

Cutaneous fibroma in a captive common snapping turtle (Chelydra serpentina).

An adult female common snapping turtle (Chelydra serpentina) had a mass on the plantar surface of the right forelimb that was removed surgically. Microscopical examination revealed many spindle cells with mild anisocytosis and anisokaryosis and a surrounding collagenous stroma. There were no mitoses. Immunohistochemistry showed that the spindle cells expressed vimentin, but not desmin. A diagnosis of cutaneous fibroma was made. Tumours are reported uncommonly in chelonian species. Cutaneous fibroma has been diagnosed in an alligator snapping turtle (Macrochelys temminckii), but not previously in a common snapping turtle.

Utilization of by-products from ethanol production as substrate for biogas production.

The aims of this work were to determine the specific biogas yields of steam-exploded sugarcane straw and bagasse as well as to estimate their energy potential under Brazilian conditions. Steam-explosion was carried out under different time and temperature conditions. The specific biogas yields were analyzed in batch-tests according to VDI 4630. Results have shown that steam-explosion pre-treatment increased the specific biogas yields of straw and bagasse significantly compared to the untreated material. The utilization of these by-products can contribute to 5% of the total energy consumption and thereby higher energy independence in Brazil. Further efforts in defining the optimum pretreatment conditions with steam-explosion as well as implementing this technology in large scale plants should be made.

The Saccharomyces cerevisiae LEP1/SAC3 gene is associated with leucine transport.

Leucine uptake by Saccharomyces cerevisiae is mediated by three transport systems, the general amino acid transport system (GAP), encoded by GAP1, and two group-specific systems (S1 and S2), which also transport isoleucine and valine. A new mutant defective in both group-specific transport activities was isolated by employing a gap1 leu4 strain and selecting for trifluoroleucine-resistant mutants which also showed greatly reduced ability to utilize L-leucine as sole nitrogen source and very low levels of [14C]L-leucine uptake. A multicopy plasmid containing a DNA fragment which complemented the leucine transport defect was isolated by selecting for transformants that grew normally on minimal medium containing leucine as nitrogen source and subsequently assaying [14C]L-leucine uptake. Transformation of one such mutant, lep1, restored sensitivity to trifluoroleucine. The complementing gene, designated LEP1, was subcloned and sequenced. The LEP1 ORF encodes a large protein that lacks characteristics of a transporter or permease (i.e., lacks hydrophobic domains necessary for membrane association). Instead, Lep1p is a very basic protein (pI of 9.2) that contains a putative bipartite signal sequence for targeting to the nucleus, suggesting that it might be a DNA-binding protein. A database search revealed that LEP1 encodes a polypeptide that is identical to Sac3p except for an N-terminal truncation. The original identification of SAC3 was based on the isolation of a mutant allele, sac3-1, that suppresses the temperature-sensitive growth defect of an actin mutant containing the allele act1-1. Sac3p has been previously shown to be localized in the nucleus. When a lep1 mutant was crossed with a sac3 deletion mutant, no complementation was observed, indicating that the two mutations are functionally allelic.

Small bowel transplantation and chronic rejection alter rat intestinal smooth muscle structure and function.

BACKGROUND: The purpose of this study was to determine whether morphologic and functional changes in intestinal smooth muscle occur after small bowel transplantation (SBTx) and during chronic rejection. METHODS: Orthotopic SBTx was performed in syngeneic (ACI-ACI, n = 6) and allogeneic (ACI-Lewis, n = 6) rat strain combinations. The latter received temporary immunosuppression (cyclosporine 15 mg/kg/body weight on postoperative days 0 to 6 once a day, postoperative days 7 to 28 every other day), which led to clinically quiescent chronic rejection of the graft by 90 days after SBTx. At that time structure and function of the jejunal muscularis externa were evaluated with histochemistry, mechanical organ bath, and intracellular electrical recording techniques. RESULTS: Histochemistry showed a 1.5-fold thickening of the intestinal muscularis externa of syngeneic grafts, although contractile properties and intracellular electrical activity were not significantly different from controls. Allogeneic, chronically rejecting grafts showed a threefold increase in the thickness of the muscularis externa as a result of both smooth muscle hyperplasia and hypertrophy. Muscle strips from chronically rejecting grafts generated only 23% of the maximal contractile force generated by controls (bethanechol 300 mumol/L). Median effective concentration and threshold values were not significantly different. Intracellular electrical activity of circular smooth muscle cells revealed a significantly more depolarized resting membrane potential and a reduction in slow wave amplitude compared with controls. CONCLUSIONS: Syngeneic SBTx resulted in a significant thickening of the muscularis externa with an apparent adaptation to control in vitro physiologic function. Allogeneic SBTx subject to chronic rejection leads to profound morphologic changes and functional impairments. Changes in muscle structure and function evolve before the clinical signs of graft rejection.

Intrapelvic calculi demonstrated in a patient after laparoscopic laser cholecystectomy: a case report.

Laparoscopic laser cholecystectomy is becoming increasingly popular in the surgical community for the treatment of gallbladder disease. Physicians will need to familiarize themselves with the imaging consequences of this new therapy. Described below is a case report of a woman in whom calculi were incidentally found within the pelvis on a plain radiograph of the abdomen after she presented to the hospital with pancreatitis. Initial confusion regarding the etiology of these calculi was solved after it was discovered that the patient had proven gallstones and a recent laparoscopic procedure. In the appropriate clinical setting, gallstones should be added to the differential consideration of intrapelvic calcifications.