Possible control mechanisms of feather follicle movement in the pectoral tract of the chicken     

I M Levinger  S Angel  M Hyams 《Veterinary research communications》1985,9(2):153-162

Feather follicle movement control was studied on feathers of the pectoral tract in the anaesthetized chicken. Dissection of nerves leading to the follicles showed that their origin was at least partially in the sympathetic ganglia. Reflectoric ruffling of feathers could be obtained after adequate stimulation. Intravenous injections of drugs in doses which influenced the circulation gave the following results: Adrenaline caused erection of feathers which was abolished by phentolamine. Noradrenaline caused up and down movements after injection only at high doses. Similar results were obtained by placing of skin pieces in saline containing the drugs. The reaction to drugs was typical always for a given group of feathers. Killing of birds and anaesthesia caused general erection of feathers which was not abolished by phentolamine. The findings suggest that adrenergic synapses are involved in feather follicle movement control, but at least another mechanism (CNS) regulates feather follicle movement.  相似文献   

Recent changes in landscape structure and function in a mediterranean region of SW Spain (1950–1984)     

Rocío Fernandez Ales  Angel Martin  Fernando Ortega  Enrique E. Ales 《Landscape Ecology》1992,7(1):3-18

Recent economic development has altered landscape structure and function of a mediterranean region in Southwestern Spain. Intensive agricultural systems have concentrated in the more fertile areas, while marginal ones have been abandoned. As a result, landscape structure has changed. Consequences of this structural change on landscape processes are discussed.  相似文献   

Estimates of environmental effects and genetic parameters for body measurements and weight in Brahman cattle raised in Mexico     

C. D. U. Magnabosco  M. Ojala  A. De Los Reyes  R. D. Sainz  A. Fernandes  T. R. Famula 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2002,119(4):221-228

A Derivative Free Restricted Maximum Likelihood (DFREML) algorithm was used with single trait and two traits animal models to estimate the variance and covariance components and thus, heritabilities and phenotypic, genetic and environmental correlations among nine different body measurements and weights of Brahman cattle raised in Mexico. The following measurements were considered: hip width, pin width, hip‐pin width, anterior height, posterior height, body length, thorax perimeter, scrotal circumference and weight. The analysis was based on a total of 1018 animals, born between 1992 and 1995, from 17 herds in the Mexican States of Chiapas, San Luis Potosi, Tabasco, Tamaulipas and Veracruz. The model included the following fixed effects: herd, year‐season of birth, sex, age of the animal and feed management. The only random effect was the direct additive genetic contribution of each animal. All fixed effects in the model were significant for all traits (p < 0.05). Estimated heritabilities for the traits were: hip width 0.57, pin width 0.32, hip‐pin width 0.41, anterior height 0.56, posterior height 0.54, body length 0.32, thorax perimeter 0.49, scrotal circumference 0.02 and weight 0.66. The magnitude of the heritabilities was medium to high, with the exception of scrotal circumference. The genetic correlations among all body measurements were consistently positive and high, ranging from 0.64 to 1.00. Although other measures showed higher genetic correlations with weight, thorax perimeter combines a high value (0.70) with ease and repeatability, making it a useful field measurement to estimate body weight when scales are not available.  相似文献   

Evaluation of clinical, macroscopic, and histopathologic response to treatment in nonhypoproteinemic dogs with lymphocytic-plasmacytic enteritis     

García-Sancho M  Rodríguez-Franco F  Sainz A  Mancho C  Rodríguez A 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(1):11-17

BACKGROUND: Lymphocytic-plasmacytic enteritis (LPE) is a common cause of chronic vomiting and diarrhea in dogs. However, little information is available about endoscopic or histopathologic improvement after therapy in dogs with LPE. HYPOTHESIS: The objective was to study the clinical, endoscopic, and histopathologic evolution of LPE during and after immunosuppressive treatment with prednisone and metronidazole. Most dogs also were treated symptomatically with metoclopramide and cimetidine. ANIMALS: Sixteen dogs with LPE and normal serum protein concentrations diagnosed at the Veterinary Medical Teaching Hospital of the Complutense University of Madrid were monitored during and after drug treatment. The control group consisted of 9 dogs that had no gastrointestinal signs for the preceding 12 months. METHODS: In this prospective clinical treatment trial, clinical, endoscopic, and histopathologic scores were evaluated to describe disease evolution during conventional therapy. Dogs with LPE were monitored for 120 days from the start of treatment. Re-evaluation was performed on post-treatment days 30, 60, 90 (end of treatment), and 120. RESULTS: The average disease activity index observed in our study fell progressively from its initial value, and the decrease between consecutive re-evaluations was statistically significant until day 60 (P = .04). Our results indicate that 75% of the animals revealed improvement of endoscopic gastric lesions (defined as a reduction of the endoscopic score) after treatment, and 75% exhibited improvement of endoscopic duodenal lesions. Statistical analysis of the data revealed significant differences between pre- and post-treatment gastric and duodenal macroscopic endoscopic lesions (P < .05). On the other hand, treatment did not lead to any significant changes in the severity of the gastric and duodenal histopathologic lesions of the affected dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Treatment of nonhypoproteinemic dogs with LPE led to clinical and endoscopic improvement, but histopathologic lesions were unchanged during therapy.  相似文献   

Complications after proximal abducting ulnar osteotomy and prognostic factors in 66 dogs     

Alan Danielski  Alexander Krekis  Russell Yeadon  Miguel Angel Solano  Tim Parkin  Aldo Vezzoni  Ingo Pfeil 《Veterinary surgery : VS》2022,51(1):136-147

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Tryptophan-accelerated electron flow through proteins     

Shih C  Museth AK  Abrahamsson M  Blanco-Rodriguez AM  Di Bilio AJ  Sudhamsu J  Crane BR  Ronayne KL  Towrie M  Vlcek A  Richards JH  Winkler JR  Gray HB 《Science (New York, N.Y.)》2008,320(5884):1760-1762

Energy flow in biological structures often requires submillisecond charge transport over long molecular distances. Kinetics modeling suggests that charge-transfer rates can be greatly enhanced by multistep electron tunneling in which redox-active amino acid side chains act as intermediate donors or acceptors. We report transient optical and infrared spectroscopic experiments that quantify the extent to which an intervening tryptophan residue can facilitate electron transfer between distant metal redox centers in a mutant Pseudomonas aeruginosa azurin. Cu(I) oxidation by a photoexcited Re(I)-diimine at position 124 on a histidine(124)-glycine(123)-tryptophan(122)-methionine(121) beta strand occurs in a few nanoseconds, fully two orders of magnitude faster than documented for single-step electron tunneling at a 19 angstrom donor-acceptor distance.  相似文献   

Comment on "Global genetic change tracks global climate warming in Drosophila subobscura"     

Rodríguez-Trelles F  Rodríguez MA 《Science (New York, N.Y.)》2007,315(5818):1497; author reply 1497

Balanyà et al. (Reports, 22 September 2006, p. 1773) build on earlier claims that chromosomal inversion polymorphisms of Drosophila subobscura are rapidly evolving in response to global warming. However, that conclusion is not adequately buttressed by their data, because they overlooked the lag between calendar and climatological dates created by the progressive lengthening of the growing season in their sampling approach.  相似文献   

Earthworm populations under tropical maize cultivation: the effect of mulching with velvetbean     

Angel?I.?Ortiz-Ceballos  Carlos?FragosoEmail author 《Biology and Fertility of Soils》2004,39(6):438-445

Earthworm populations were studied in three tropical agroecosystems of southern Mexico: improved maize with a Mucuna pruriens cover crop (MM), continuous conventional maize (CM) and pastures (P). Three replicates and six monoliths were sampled in each agroecosystem. Three earthworm species were found, two native (Balanteodrilus pearsei, Larsonidrilus orbiculatus) and one exotic (Polypheretima elongata). In all systems, the dominant species was B. pearsei, with negligible presence of the exotic species in MM and P plots. Total abundance was significantly higher in MM than in CM; and earthworm biomass was also higher in MM than in CM and P. Juveniles of both native species dominated, mainly concentrated in the top 20 cm of soil. B. pearsei and L. orbiculatus displayed different preferences (within each agroecosystem) for soil organic matter, N and temperature. Further experiments are required to investigate whether mulching with M. pruriens results in an increased earthworm abundance and biomass through a N-improvement effect or as a result of microclimatic changes and to study the extent to which earthworms and M. pruriens are synergistic in enhancing maize growth.  相似文献   

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil     

Cantera RG  Zamarreño AM  García-Mina JM 《Journal of agricultural and food chemistry》2002,50(26):7609-7615

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.  相似文献   

Usefulness of Foliar Nitrogen-Sulfur Ratio in Spring Red Wheat     

Nahuel Ignacio Reussi Calvo  Hernán Eduardo Echeverría  Hernán Sainz Rozas 《Journal of plant nutrition》2013,36(9):1612-1623

Sulfur (S) availability indicators are necessary for a rational use of fertilizers. Experiments were carried out to evaluate the sensitivity and stability of nitrogen (N):S ratio in spring red wheat. Yield responses were determined in three replications over five experimental sites. Sulfur application did not increase N concentration in plant, whereas the effect on total S concentration was varied. Results showed 25, 35, 80, and 85% correctly diagnosed samples at stages Z22, Z24, Z31, and Z39, respectively. In treatments without S limitations, a decrease in N:S ratio was observed as the crop cycle advanced. Nitrogen: S ratio differed according to the site; however, these variations tend to decrease as the crop cycle advance. In summary, for spring red wheat, N:S ratio in plant is a useful method for S deficiencies diagnostic from the end of tillering to flag leaf.  相似文献