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61.
62.
Background
The Weberian apparatus of otophysine fishes facilitates sound transmission from the swimbladder to the inner ear to increase hearing sensitivity. It has been of great interest to biologists since the 19th century. No studies, however, are available on the development of the Weberian ossicles and its effect on the development of hearing in catfishes.Methodology/Principal Findings
We investigated the development of the Weberian apparatus and auditory sensitivity in the catfish Lophiobagrus cyclurus. Specimens from 11.3 mm to 85.5 mm in standard length were studied. Morphology was assessed using sectioning, histology, and X-ray computed tomography, along with 3D reconstruction. Hearing thresholds were measured utilizing the auditory evoked potentials recording technique. Weberian ossicles and interossicular ligaments were fully developed in all stages investigated except in the smallest size group. In the smallest catfish, the intercalarium and the interossicular ligaments were still missing and the tripus was not yet fully developed. Smallest juveniles revealed lowest auditory sensitivity and were unable to detect frequencies higher than 2 or 3 kHz; sensitivity increased in larger specimens by up to 40 dB, and frequency detection up to 6 kHz. In the size groups capable of perceiving frequencies up to 6 kHz, larger individuals had better hearing abilities at low frequencies (0.05–2 kHz), whereas smaller individuals showed better hearing at the highest frequencies (4–6 kHz).Conclusions/Significance
Our data indicate that the ability of otophysine fish to detect sounds at low levels and high frequencies largely depends on the development of the Weberian apparatus. A significant increase in auditory sensitivity was observed as soon as all Weberian ossicles and interossicular ligaments are present and the chain for transmitting sounds from the swimbladder to the inner ear is complete. This contrasts with findings in another otophysine, the zebrafish, where no threshold changes have been observed. 相似文献63.
64.
A. Kőrösi Molnár B. Podmaniczky P. Kürti R. Glávits Gy. Virág Zs. Szabó Zs. Farkas 《Probiotics and antimicrobial proteins》2011,3(1):8-14
This trial was conducted to study the effects of different Bacillus subtilis concentrations on immune response of broiler chickens. There were 5 treatment groups: control, with no added B. subtilis supplementation, and 4 treatment groups receiving feed supplemented with different concentrations of B. subtilis. The trial was conducted with 225 broilers. The weight of broiler chickens in all groups receiving feed supplemented with B. subtilis was significantly higher and the feed conversion was better independently of the concentration than that of the control chickens. The degree of diffuse lymphohistiocytic infiltration and the number of solitary lymphoid follicles in the mucosa increased in accordance with the B. subtilis concentration of the feed. The birds from the groups fed B. subtilis-supplemented diets had significantly increased antibody responses to vaccination against Newcastle disease virus. The appearance of increased diffuse lymphohistiocytic infiltration and solitary lymphoid follicles in the mucosa and a stronger response to NDV indicate increased immunological response in chickens fed with a B. subtilis-supplemented diet. 相似文献
65.
66.
Rizzatti-Barbosa CM Ribeiro MC Silva-Concilio LR Di Hipolito O Ambrosano GM 《Gerodontology》2005,22(2):112-115
Background: Elongation and calcification of the stylohyoid ligament complex may be correlated with Eagle's syndrome. The styloid complex pathogenesis is still being debated. Objective: The aim of this study was to investigate the prevalence of stylohyoid ligament complex elongation in panoramic radiographs of 2252 patients in a Brazilian adult, partially edentulous population, of both sexes. Methods: The radiographs, taken in the Semiology Department at the Dental School in Brazil, were randomly selected from January 1997 to December 2000. The stylohyoid ligament complexes were measured from the cranial base up to the osseous tip of each process. Mineralisation of the complex of more than 25 mm in length on the radiograph was considered to be abnormal. The same operator made all the measurements. The lengths of the areas of mineralisation were recorded, and whether the condition was bilateral was noted. Results: This abnormality was present in both sexes. A calcified complex was found in 451 of the 2252 patients. The majority of these calcified complexes (n = 248; 54.9%) were bilateral. Three hundred and fifty‐six (39.5%) of them were longer than 25 mm (and so were abnormal), and the length varied from 26.1 to 65 mm. (average length = 27.8 mm). Forty (4.4%) of the abnormalities were longer than 50 mm, and of these 36 (90%) were in the 40–59 year age group. The mean length of a mineralised stylohyoid ligament complex in patients in the 60–79 year age group was 32.75 mm. Conclusion: The results suggested that an anatomical variant of the stylohyoid ligament complex was more frequently found in the elderly female population, although this abnormality was present in both sexes. There was a greater tendency for the abnormality to be present in patients between 60 and 79 years of age. 相似文献
67.
Incompatibility recognition systems preventing self-fertilization have evolved several times in independent lineages of Angiosperm plants, and three main model systems are well characterized at the molecular level [the gametophytic self-incompatibility (SI) systems of Solanaceae, Rosaceae and Anthirrhinum, the very different system of poppy, and the system in Brassicaceae with sporophytic control of pollen SI reactions]. In two of these systems, the genes encoding both components of pollen-pistil recognition are now known, showing clearly that these two proteins are distinct, that is, SI is a lock-and-key mechanism. Here, we review recent findings in the three well-studied systems in the light of these results and analyse their implications for understanding polymorphism and coevolution of the two SI genes, in the context of a tightly linked genome region. 相似文献
68.
Assunção-Miranda I Guilherme AL Reis-Silva C Costa-Sarmento G Oliveira MM Vieyra A 《Regulatory peptides》2005,127(1-3):151-157
Angiotensin II (Ang II) increases the cytosolic Ca2+ concentration in different cell types. In this study, we investigate the effect of Ang II on the Ca2+ ATPase of purified basolateral membranes of kidney proximal tubules. This enzyme pumps Ca2+ out of the cytosol in a reaction coupled to ATP hydrolysis, and it is responsible for the fine-tuned regulation of cytosolic Ca2+ activity. Ca2+-ATPase activity is inhibited by picomolar concentrations of Ang II, with maximal inhibition being attained at approximately 50% of the control values. The presence of raising concentrations (10(-11) to 10(-7) M) of losartan (an AT1-receptor antagonist) or PD123319 (an AT2-receptor antagonist) gradually reverts inhibition by Ang II. Both the phospholipase C (PLC) inhibitor U-73122 (10(-6) M) and the inhibitor of protein kinase C (PKC) staurosporine (10(-7) M) prevent inhibition of the Ca2+ pump by Ang II. Incubation of the previously isolated membranes with a PKC activator-the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (10(-8) M)-mimics the inhibition found with Ang II, and the effects of the compounds are not additive. Taken as a whole, these results indicate the Ang II inhibits Ca2+-ATPase by activation of a PKC system present in primed state in these membranes after binding of the hormone to losartan- and PD123319-sensitive receptors coupled to a PLC. Therefore, inhibition of the basolateral membrane Ca2+-ATPase by kinase-mediated phosphorylation appears to be one of the pathways by which Ang II promotes an increase in the cytosolic Ca2+ concentration of proximal tubule cells. 相似文献
69.
Mazo Fávero Gimenes V Da Glória de Souza M Ferreira KS Marques SG Gonçalves AG Vagner de Castro Lima Santos D Pedroso e Silva Cde M Almeida SR 《Microbes and infection / Institut Pasteur》2005,7(4):708-713
Chromoblastomycosis is a chronic, often debilitating, suppurative, granulomatus mycosis of the skin and subcutaneous tissues beginning after inoculation trauma. It occurs world-wide, but is more frequently observed in tropical countries such as Brazil. The disease is usually insidious, and the lesions increase slowly but progressively, not responding to the usual treatments and quite often reappearing. The host defense mechanism in chromoblastomycosis has not been extensively investigated. Some studies have focused on fungus-host interaction, showing a predominantly cellular immune response, with the activation of macrophages involved in fungus phagocytosis. Although phagocytosis did occur, death of fungal cells was rarely observed. The ability of Fonsecaea pedrosoi to produce secreted or cell wall-associated melanin-like components, protects against destruction by host immune cells in vitro. Until now, the T cell immune response in chromoblastomycosis is undefined. In the present work, it was shown that, in patients with the severe form of the disease, predominant production of IL-10 cytokine, low levels of IFN-gamma and inefficient T cell proliferation were induced. In contrast, in patients with a mild form of the disease, predominant production of IFN-gamma cytokine, low levels of IL-10 and efficient T cell proliferation were observed. 相似文献
70.
Yadhu?Kumar Ralf?Westram Sebastian?Behrens Bernhard?Fuchs Frank?Oliver?Gl?ckner Rudolf?Amann Harald?Meier Wolfgang?LudwigEmail author 《BMC bioinformatics》2005,6(1):61