1,721,008 research outputs found
In silico detection and experimental validation of novel alternative transcript factor A
No full textIdentification and characterization of tissue-specific alternative transcripts of Tfam gene by both computational and experimental approaches
No full textProliferation and Apoptosis of Cat (Felis catus) Male Germ Cells during Breeding and Non-Breeding Seasons
Full text linkThe domestic cat (Felis catus) is a seasonal-breeding species whose reproductive period starts when the day length increases. Since the existing information on cat spermatogenesis is limited and somewhat contradictory, in the present study, germ cell proliferation and apoptosis in feral adult tomcats orchiectomized during reproductive (reproductive group, RG; February–July) and non-reproductive (non-reproductive group, NRG; November and December) seasons were compared. Cross-sections taken from the middle third of the left testis were chemically fixed and embedded in paraffin wax. Histological sections were processed for the immunohistochemical detection of proliferating germ cells (PCNA) and for the identification of apoptotic cells (TUNEL method). The percentage of PCNA-positive spermatogonia was higher in the RG than in the NRG. On the contrary, germ cell apoptosis was higher in the NRG than in the RG. Our results confirm that cat spermatogenesis is modulated on a seasonal basis and suggests that spermatogenesis control involves changes in germ cell proliferation and apoptosis according to a common paradigm of seasonally breeding species
Increased melanomacrophage centres in the liver of reproductively dysfunctional female greater amberjack Seriola dumerili (Risso, 1810)
Full text linkThe greater amberjack Seriola dumerili is a new aquaculture fish that may display reproductive dysfunctions. During extensive follicular atresia, which is a common reproductive dysfunction in females during vitellogenesis, part of the reabsorbed yolk returns to the liver to be metabolized and recycled. Melanomacrophage centres (MMCs) are aggregates of macrophage-like cells that play a role in the destruction, detoxification and recycling of endogenous and exogenous materials, and have been associated with systemic stress. Wild and captive-reared greater amberjack were sampled in the Mediterranean Sea during two different phases of the reproductive cycle. The liver of reproductively dysfunctional captive-reared females sampled during the spawning season showed a high density of both MMCs and apoptotic cells. A weak liver anti-cytochrome P450 monooxygenase 1A immunoreactivity was observed, suggesting that the examined fish were not exposed to environmental pollutants. We propose that the observed increase in MMCs and apoptosis in captive-reared fish was related to the hepatic overload associated to the metabolism of yolk proteins reabsorbed during extensive follicular atresia. Since follicular atresia is a frequent physiological and pathological event in teleosts, we suggest that the reproductive state should be always assessed when MMCs are used as markers of exposure to stress or pollutants
Spermatogenesis advancement in pre-pubertal meagre Argyrosomus regius treated with recombinant gonadotropins
No full textΤhe effects of recombinant meagre follicle stimulating hormone (rFsh) and luteinizing hormone (rLh) were evaluated on testicular maturation in pre-pubertal meagre Argyrosomus regius, an upcoming aquaculture species in the Mediterranean region. Fish (body mass 1092.9 ± 178.8 g) received seven weekly injections of meagre rFsh, together with an rLh injection at week 6. One group was further treated with weekly rFsh or rLh until week 11 and was sacrificed at week 12 (rFsh/rLh group, TREATED 12). The second group received further weekly injections of rFsh until week 12 and was then left untreated until week 21 (single rLh group, TREATED 21). Control fish received injections of saline solution. At week 12, the testes of the rFsh/rLh-treated fish (TREATED 12) showed increased gonadosomatic index and seminiferous tubule diameter, reduction of spermatogonial density, increase of post-meiotic spermatocysts and accumulation of luminal spermatozoa. In the single rLh-treated group (TREATED 21), apoptosis increased towards pre-treatment levels, demonstrating that the withdrawal of the Fsh stimulus ceased the process of spermatogenesis. The results demonstrated the effectiveness of rFsh/rLh treatment in stimulating testicular growth, spermiogenesis and spermiation in pre-pubertal meagre
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
IN VITRO EFFECTS OF RECOMBINANT GONADOTROPINS ON GONAD MATURATION IN PRE-PUBERTAL ATLANTIC BLUEFIN TUNA THUNNUS THYNNUS (L.)
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Molecular characterization and functional analysis of four b-1,4-endoglucanases from the root-lesion nematode Pratylenchus vulnus
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