Efeito do período pós-parto na fertilidade de vacas de corte submetidas à re-sincronização do estro.

Um grupo de 118 vacas dividido segundo o período pós-parto em G1 (<42 dias pós-parto) e G2 (3 42 dias) foi submetido a sincronização do estro e inseminação artificial em momento pre-estabelecido (IAME). Doze dias depois procedeu-se a re-sincronização com um implante de 6 mg de norgestomet, que foi retirado nove dias depois. Uma segunda IAME foi feita 48 horas depois, apenas nas vacas nao-prenhes a 1 IAME. As vacas do G2 tiveram taxa de prenhez maior na IAME inicial. As taxas de prenhez a 2 IA e cumulativa não deferiram entre grupos

Functional visual sensitivity to ultraviolet wavelengths in the Pileated Woodpecker (\u3ci\u3eDryocopus pileatus\u3c/i\u3e), and its influence on foraging substrate selection

Most diurnal birds are presumed visually sensitive to near ultraviolet (UV)wavelengths, however, controlled behavioral studies investigating UV sensitivity remain few. Although woodpeckers are important as primary cavity excavators and nuisance animals, published work on their visual systems is limited. We developed a novel foraging-based behavioral assay designed to test UV sensitivity in the Pileated Woodpecker (Dryocopus pileatus). We acclimated 21 wild-caught woodpeckers to foraging for frozen mealworms within 1.2 m sections of peeled cedar (Thuja spp.) poles.We then tested the functional significance of UV cues by placing frozen mealworms behind UV-reflective covers, UV-absorptive covers, or decayed red pine substrates within the same 1.2 m poles in independent experiments. Behavioral responses were greater toward both UV-reflective and UV-absorptive substrates in three experiments. Study subjects therefore reliably differentiated and attended to two distinct UV conditions of a foraging substrate. Cue-naïve subjects showed a preference for UV-absorptive substrates, suggesting that woodpeckers may be pre-disposed to foraging from such substrates. Behavioral responses were greater toward decayed pine substrates (UV-reflective) than sound pine substrates suggesting that decayed pine can be a useful foraging cue. The finding that cue-naïve subjects selected UV-absorbing foraging substrates has implications for ecological interactions of woodpeckers with fungi.Woodpeckers transport fungal spores, and communication methods analogous to those of plant-pollinator mutualisms (i.e. UV-absorbing patterns) may have evolved to support woodpecker-fungus mutualisms

Visual cues for woodpeckers: light reflectance of decayed wood varies by decay fungus

The appearance of wood substrates is likely relevant to bird species with life histories that require regular interactions with wood for food and shelter. Woodpeckers detect decayed wood for cavity placement or foraging, and some species may be capable of detecting trees decayed by specific fungi; however, a mechanism allowing for such specificity remains unidentified.We hypothesized that decay fungi associated with woodpecker cavity sites alter the substrate reflectance in a species-specific manner that is visually discriminable by woodpeckers. We grew 10 species of wood decay fungi from pure cultures on sterile wood substrates of 3 tree species. We then measured the relative reflectance spectra of decayed and control wood wafers and compared them using the receptor noise-limited (RNL) color discrimination model. The RNL model has been used in studies of feather coloration, egg shells, flowers, and fruit to model how the colors of objects appear to birds. Our analyses indicated 6 of 10 decayed substrate/control comparisons were above the threshold of discrimination (i.e., indicating differences discriminable by avian viewers), and 12 of 13 decayed substrate comparisons were also above threshold for a hypothetical woodpecker. We conclude that woodpeckers should be capable of visually detecting decayed wood on trees where bark is absent, and they should also be able to detect visually species-specific differences in wood substrates decayed by fungi used in this study. Our results provide evidence for a visual mechanism by which woodpeckers could identify and select substrates decayed by specific fungi, which has implications for understanding ecologically important woodpecker–fungus interactions. El aspecto de los sustratos de madera posiblemente sea relevante para especies de aves que tienen historias de vida que dependen de interacciones regulares con la madera para alimentaci´on y resguardo. Los pa´jaros carpinteros detectan la madera degradada para establecer sus cavidades o para forrajear, y algunas especies podr´ıan ser capaces de detectar a´rboles que son degradadas por alg´un hongo en particular. Sin embargo, a´un no se identifica un mecanismo que permita identificar tal especificidad. Nuestra hip´otesis es que los hongos xil ´ofagos asociados a sitios con cavidades para carpinteros alteran la reflectancia del sustrato en una manera espec´ıfica a especie que es visualmente discernible para los carpinteros. Cultivamos 10 especies de hongos xil ´ofagos a partir de cultivos puros en sustratos est´eriles de madera de tres especies de a´rboles. A continuaci´on, medimos el espectro de reflectancia de la madera de la madera degradada y trozos de madera control, y las comparamos entre s´ı usando el modelo de discriminaci´on de color del receptor de ruido limitado (RNL, por sus siglas en ingl´es). El modelo RNL ha sido utilizado en estudios de coloraci´on de plumas, cascar´on de huevo, flores y frutos para modelar c´omo perciben las aves el color de los objetos. Nuestros ana´lisis indican que 6 de 10 comparaciones sustrato/control estuvieron por encima del umbral de discriminaci´on (e.g., indicando diferencias discernibles por observadores aviares) y que las comparaciones de 12 de los 13 sustratos degradados estuvieron por encima del umbral para un carpintero hipot´etico. Concluimos que los carpinteros deben ser capaces de detectar visualmente la madera degradada en a´rboles donde la corteza esta´ ausente y tambi´en deben detectar visualmente diferencias espec´ıficas a especie en los sustratos de madera degradada por los hongos utilizados en este estudio. Nuestros resultados proveen evidencia de un mecanismo visual por medio del cual los pa´jaros carpinteros pueden identificar y seleccionar los sustratos degradados por hongos espec´ıficos, lo cual tiene implicaciones en nuestro entendimiento de las importantes interacciones entre carpinteros y hongos

Gastroesophageal junction adenocarcinoma displays abnormalities in homologous recombination and nucleotide excision repair

OBJECTIVE: Esophageal adenocarcinoma (EAC) continues to be a disease associated with high mortality. Among the factors leading to poor outcomes are innate resistance to currently available therapies, advanced stage at diagnosis, and complex biology. Platinum and ionizing radiation form the backbone of treatment for the majority of patients with EAC. Of the multiple processes involved in response to platinum chemotherapy or ionizing radiation, deoxyribonucleic acid (DNA) repair has been a major player in cancer sensitivity to these agents. DNA repair defects have been described in various malignancies. The purpose of this study was to determine whether alterations in DNA repair are present in EAC compared with normal gastroesophageal tissues. METHODS: We analyzed the expression of genes involved in homologous recombination (HR), nonhomologous end-joining, and nucleotide excision repair (NER) pathways in 12 EAC tumor samples with their matched normal counterparts. These pathways were chosen because they are the main pathways involved in the repair of platinum- or ionizing-radiation-induced damage. In addition, abnormalities in these pathways have not been well characterized in EAC. RESULTS: We identified increased expression of at least one HR gene in eight of the EAC tumor samples. Alterations in the expression of EME1, a structure-specific endonuclease involved in HR, were the most prevalent, with messenger (m)RNA overexpression in six of the EAC samples. In addition, all EAC samples revealed decreased expression of at least one of numerous NER genes including XPC, XPA, DDB2, XPF, and XPG. CONCLUSION: Our study identified DNA repair dysregulation in EAC involving two critical pathways, HR and NER, and is the first demonstration of EME1 upregulation in any cancer. These DNA repair abnormalities have the potential to affect a number of processes such as genomic instability and therapy response, and the consequences of these defects deserve further study in EAC

Chronic hindlimb ischemia impairs functional vasodilation and vascular reactivity in mouse feed arteries

Vasodilation of lower leg arterioles is impaired in animal models of chronic peripheral ischemia. In addition to arterioles, feed arteries are a critical component of the vascular resistance network, accounting for as much as 50% of the pressure drop across the arterial circulation. Despite the critical importance of feed arteries in blood flow control, the impact of ischemia on feed artery vascular reactivity is unknown. At 14 days following unilateral resection of the femoral–saphenous artery–vein pair, functional vasodilation of the profunda femoris artery was severely impaired, 11 ± 9 versus 152 ± 22%. Although endothelial and smooth muscle-dependent vasodilation were both impaired in ischemic arteries compared to control arteries (Ach: 40 ± 14 versus 81 ± 11%, SNP: 43 ± 12 versus and 85 ± 11%), the responses to acetylcholine and sodium nitroprusside were similar, implicating impaired smooth muscle-dependent vasodilation. Conversely, vasoconstriction responses to norepinephrine were not different between ischemic and control arteries, −68 ± 3 versus −66 ± 3%, indicating that smooth muscle cells were functional following the ischemic insult. Finally, maximal dilation responses to acetylcholine, ex vivo, were significantly impaired in the ischemic artery compared to control, 71 ± 9 versus 97 ± 2%, despite a similar generation of myogenic tone to the same intravascular pressure (80 mmHg). These data indicate that ischemia impairs feed artery vasodilation by impairing the responsiveness of the vascular wall to vasodilating stimuli. Future studies to examine the mechanistic basis for the impact of ischemia on vascular reactivity or treatment strategies to improve vascular reactivity following ischemia could provide the foundation for an alternative therapeutic paradigm for peripheral arterial occlusive disease

Differential gene expression profiling of esophageal adenocarcinoma

BackgroundDifferential gene expression offers an attractive means by which to study genes that may be involved in disease development and/or progression. We performed quantitative gene expression in various stages of esophageal adenocarcinoma, treated exclusively by surgery with complete 2-field lymphadenectomy, in an attempt to discern genes involved in disease progression as well as genes that may predict survival.MethodsGene expression profiling was accomplished by cDNA-mediated annealing, selection, extension, and ligation (DASL) assay. RNA was extracted from 89 archived formalin-fixed, paraffin-embedded esophageal adenocarcinoma tissues. DASL assay was performed with the Sentrix Universal Array (Illumina Corp, San Diego, Calif) of 502 known cancer-related genes. Bioinformatics tools were used to determine significant differential gene expression in T1-2 versus T3-4 tumors and tumors without lymph node involvement (N0) versus tumors with lymph node involvement (N+). Gene expression was also correlated with overall survival.ResultsTwenty-one genes were overexpressed in T1-2 compared with T3-4 tumors (false discovery rate of 0). Underexpression of 1 gene was seen in N+ compared with N0 tumors (false discovery rate of 0). For overall survival, underexpression of 9 genes correlated with long survival.ConclusionsUsing differential gene expression of 502 known cancer genes, we identified genes that may be involved at various stages in the progression of esophageal adenocarcinoma. We also identified genes that may correlate with prolonged survival and, thus, may serve as prognostic markers. These findings may provide further insight into the mechanisms of development and/or progression of esophageal adenocarcinoma. Prospective studies are needed to verify the prognostic value of these genes