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631.
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633.
Two sand sole species, Solea lascaris and Solea impar , are common on the western coast of Brittany, France. Their reproduction (oogenesis and spawning) has been studied by following the gonadosomatic index, histological changes in ovary development, and oocyte diameter distribution. Both species have a prolonged spawning season, from spring to late summer. Each mature female breeds twice during the spawning season: in May and July for 5. lascaris , and in early June and July for 5. impar. Throughout the spawning season, several oocyte batches undergo vitellogenesis and there is a continuous recruitment of immature or primary oocytes into vitellogenesis. The two species are thus serial synchronous spawners. This, together with oocyte atresia late in the season (especially noticeable in S. impar ) makes fecundity estimation difficult.  相似文献   
634.
Aphids infest many plants and cause damage by depriving them of nutrients and by transmitting many viral diseases. Aphid infestation and arbovirus transmission are controlled by establishment (or not) of a compatible reaction between the insects and the plants. This reaction is the result of defense reactions of the plant and counter-defense reactions of the parasite. Contrarily to plant-bacteria, plant-fungi and plant-herbivorous insects pathosystems, the plant-aphid pathosystem is understudied, although recent advances have begun to uncover some of its details. Especially the very early steps in plant-aphid interactions are hardly known. We here resume the present knowledge of these interactions. We discuss further how an aphid-transmitted plant virus that is transmitted during the first moments of the plant-aphid encounter, might help to study the very early plant aphid interactions.  相似文献   
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636.
The study of the acute toxicity of two barbiturics anaesthetics (pentobarbital and thiopental) shows the newborn period a higher susceptibility of the young rat, probably due to an immaturity of biotransformations enzymatic systems or to an increased blood-brain-barrier permeability.  相似文献   
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The major cellular receptor for the primate immunodeficiency viruses is the CD4 molecule. As well as mediating virion attachment to the cell surface, CD4 is thought to activate the viral fusion pathway. CD4 is not, however, sufficient for viral entry; other molecules are probably involved, and in certain circumstances these may substitute for CD4. Viral tropism and cytopathogenicity are also influenced by receptor interactions.  相似文献   
639.
This paper reports the effects of X-irradiation on ovulation rate, cyclicity and progesterone and FSH levels in Ile-de-France ewes (4 control and 16 irradiated) after they were treated during the breeding season. The doses used (800 and 2 400 R) destroyed 50% of all size classes of the follicular population. Ovulation occurred in 87% of the treated ewes (ovulation rate = 1) when they were irradiated 24 h after luteolysis; 78% of the corpora lutea resulting from these ovulations were normal as to length and progesterone production. FSH in treated ewes started to increase 20 h after treatment and remained higher than in the controls until ovulation time. Later, while these levels were similar between groups on the day of ovulation, high ovulatory levels persisted in irradiated ewes. In the next cycles, the length of the follicular phases, ovulation rate and progesterone and FSH levels were similar between groups.  相似文献   
640.
Familial Mediterranean fever (FMF), mevalonate kinase deficiency (MKD), and tumour necrosis factor (TNF) receptor-1-associated periodic syndrome (TRAPS) are monogenic disorders included under the term??hereditary fever syndromes??. These diseases are characterized by recurrent episodes of fever and inflammation and arise from mutations of genes regulating the innate immune system. The present review describes the clinical and genetic spectrum of hereditary fever syndromes, which are of importance for genetic counseling.  相似文献   
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