1,720,977 research outputs found
Isolation of a mRNA encoding a glycine-proline-rich beta-keratin expressed in the regenerating epidermis of lizard
No full textDuring scale regeneration in lizard tail, an active differentiation of beta-keratin synthesizing cells occurs. The cDNA and amino acid sequence of a lizard beta-keratin has been obtained from mRNA isolated from regenerating epidermis. Degenerate oligonucleotides, selected from the translated amino acid sequence of a lizard claw protein, were used to amplify a specific lizard keratin cDNA fragment from the mRNA after reverse transcription with poly dT primer and subsequent polymerase chain reaction (3'-rapid amplification of cDNA ends analysis, 3'-RACE). The new sequence was used to design specific primers to obtain the complete cDNA sequence by 5'-RACE. The 835-nucleotide cDNA sequence encodes a glycine-proline-rich protein containing 163 amino acids with a molecular mass of 15.5 kDa; 4.3% of its amino acids is represented by cysteine, 4.9% by tyrosine, 8.0% by proline, and 29.4% by glycine. Tyrosine is linked to glycine, and proline is present mainly in the central region of the protein. Repeated glycine-glycine-X and glycine-X amino acid sequences are localized near the N-amino and C-terminal regions. The protein has the central amino acid region similar to that of claw-feather, whereas the head and tail regions are similar to glycine-tyrosine-rich proteins of mammalian hairs. In situ hybridization analysis at light and electron microscope reveals that the corresponding mRNA is expressed in cells of the differentiating beta-layers of the regenerating scales. The synthesis of beta-keratin from its mRNA occurs among ribosomes or is associated with the surface of beta-keratin filaments
La produzione di novellame di specie ittiche marine in Italia
No full textIn the last five years, the productive capacity of the Italian marine fish hatcheries has increased more than thrice, rising from 3.4 million fingerlings in 1986-'87 to 11 million in 1990-'91. The 18 hatcheries that are currently operative can be classified into three main types, named traditional, transitional and advanced, according to their technological level evaluated on the basis of: 1) reproduction control; 2) water quality control; 3) larval rearing technique; 4) fry quality and 5) research for technological improvement. The first type is characterized by the absence of broodfish stocking, occasional water quality control, high percentage of abnormal larvae (around 60) and low productive capacity. In transitional hatcheries, a small broodstock is maintained and larvae are reared up to 50 days in closed or partially closed circuit systems with control over the most important water parameters. Nutritionally enriched rotifers and Artemia are often used for larval feeding and the incidence of developmental abnormalities is on the average about 35. In almost all advanced hatcheries, operations are carried out in closed or semi-closed circuit systems designed according to modern engineering and biotechnological criteria. Gametes are provided by a permanent selected broodstock which is subjected to ecophysiological conditioning. Devices to avoid gas hypersaturation of the water and to remove oily films from its surface are usually present. Annual production per hatchery reaches 2 million fingerlings with 90 inflated swim bladder and no more than 5 deformities. Larval survival rate is generally higher than 10. Laboratory work to reduce theratologies and diseases and to improve fish quality through mass selection, chromosome manipulation and sex control is implemented in some cases
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
Studying the effect of sea level rise on nuisance flooding due to groundwater in a coastal urban area with aging infrastructure
No full textIn this paper, we present a study focused on the effect of sea level rise (SLR) on nuisance flooding due to groundwater (or groundwater flooding). A densely populated coastal urban area along a river estuary was selected for this work. We developed a three-dimensional (3D) shallow unconfined aquifer model of the site. We calibrated it with field measurements and used it to predict areas prone to groundwater flooding under different SLR scenarios. Results show that the water table is controlled by the river level as well as by aging infrastructure such as aging combined sewer and drinking water networks which drain and recharge the unconfined aquifer. Steady-state simulations run considering current river level scenarios show a very shallow aquifer throughout the area and simulations under different SLR scenarios predict that the water table starts to emerge from the ground in the low-lying parts of the site for 0.4 m of SLR. Overall, this work suggests that groundwater in coastal urban areas is regulated by anthropogenic and natural systems and is susceptible to climate change contributing to inundation together with marine flooding and intense precipitation
Prove preliminari di riproduzione indotta e allevamento larvale del pesce gatto africano, Clarias gariepinus (Burch.)
No full textIn spring and summer 1988, hormone-induced reproduction trials were carried out on Clarias gariepinus, a species of catfish which, although native to Africa, is also reared in temperate areas in heated waters from power and industrial plants. Half the tested females were injected with carp pituitary extract (3 mg/kg live weight), while the other half received 10 mg/kg of 20- β-dihydro-progesterone. Males were not treated. All the females spawned successfully and the eggs were fertilized with testes homogenate. Hatching rate was 33% from the group treated with pituitary extract and 25% from the other group. For a period of 10 days after resorption of the yolk sac, half the fry from each group received nauplia of Artemia salina and the other half a commercial feed. The best survival rates were obtained with the natural diet (35 and 55% vs 20 and 25% respectively) and in the fry from females treated with 20-β-dihydro-progesterone
COMPARATIVE ETHOLOGICAL AND BIOCHEMICAL ASPECTS OF COURTSHIP PHEROMONES IN EUROPEAN NEWTS
No full text
Variations 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
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