Evolution de la mortalité et des malformations des embryons de Poulet incubés artificiellement

Summary During artificial incubation the chick embryos show a 30% mortality with the above mentioned material (incubator and breed of chicken). The 2 critical periods for the embryos are the first 5 days of incubation and the 2 days of hatching. In the same experience, the author found 4% of malformed embryos. All the values are calculated on the total of 503 fertile eggs. The author believes that the above mentioned figure represents a standard curve for a definite material.     

Nerve endings isolated from chick embryonic optic tectum. 1. Developmental aspects of intact synaptosomes

Summary Fractions enriched in nerve endings (synaptosomes) have been isolated from optic tectum of chick embryos at 16 and 18 days of incubation and of chicks immediately after hatching. Morphological aspects of nerve endings have been examined with special regard to the appearance of synaptic thickenings and synaptic vesicles.     

The ontogeny ofa-foetoprotein in the chicken

Summary The ontogeny ofa-foetoprotein (AFP) has been studied in the chicken using polyacrylamide gel gradient electrophoresis and electroimmunoassay from 7 days of incubation until after hatching. The results are discussed in the light of previous on the ontogeny of AFP in mammals.     

Dopamine-β-Hydroxylase activity in serum of developing rats

Summary After birth, the activity of dopamine--hydroxylase in rat serum increased up to 14 days maximal level and decreased gradully to reach a low level at 42 days which was about 14% of the activity of maximal activity at 14 days.     

Sexual differences in the development of plasma thyroxine levels in the embryo and young chick]

Plasma thyroxine (T4) levels were separately ascertained in male and female embryo and young chicken from the 12th day of incubation till the 4th day after hatching by the thyroxine binding globulin technique. In both sexes, plasma T4 reach a peak the 20th day of incubation, but values are significantly higher in females. A sharp decrease occurred thereafter, plasma T4 tending toward adult values the 4th day after hatching.     

Positive and negative inotropic effects of carbachol on the embryonic chick atrium.

The effect of carbachol on twitch tension of atrial preparations from chick embryos of different incubation ages (3-14 days) was studied. At every age carbachol evoked negative (at low concentrations) and positive (at higher concentrations) inotropic responses. Maximal response values for both effects increased with age; in 3- and 5-day atria the positive inotropic response prevailed. The muscarinic antagonist pirenzepine inhibited the positive (on 5-day atria) and negative (on strips of 14-day atria) inotropic effects of carbachol with pA2 values of 6.8 and 8.0, respectively, suggesting that muscarinic receptors mediating these effects belong to different receptor subtypes.     

Weight changes in the eggs of Leucophaea maderae Fabr. (Insecta, Dictyoptera)]

Eggs in Leucophaea maderae are present in an ootheca which remains in the broodsac until hatching of the larvae. During incubation, the water content of the eggs increases from 36 to 77%, the dry weight remaining constant. Water is possibly provided by the mother.     

Encephalomyocarditis (EMC) virus-induced diabetes mellitus prevented by Corynebacterium parvum in mice

Corynebacterium parvum prevented the development of encephalomyocarditis virus-induced diabetes in mice, when it was given 3-14 days before the virus infection. This treatment inhibited virus replication in the pancreas of the infected mice at an early stage of the infection.     

Positive and negative inotropic effects of carbachol on the embryonic chick atrium

The effect of carbachol on twitch tension of atrial preparations from chick embryos of different incubation ages (3–14 days) was studied. At every age carbachol evoked negative (at low concentrations) and positive (at higher concentrations) inotropic responses. Maximal response values for both effects increased with age; in 3- and 5-day atria the positive inotropic response prevailed. The muscarinic antagonist pirenzepine inhibited the positive (on 5-day atria) and negative (on strips of 14-day atria) inotropic effects of carbachol with pA₂ values of 6.8 and 8.0, respectively, suggesting that muscarinic receptors mediating these effects belong to different receptor subtypes.     

Development of post-hatching melatonin rhythm in zebra finches (Poephila guttata)

We examined levels of melatonin in the pineal, eyes and plasma over a 24 h period during development in the altricial zebra finch. Beginning as early as 2 days after hatching there was a distinct 24 h rhythm in melatonin in the pineal and plasma. Beginning at day seven after hatching there was also a 24 h rhythm present in the eyes. In the pineal and eyes the amplitude of the 24 h rhythm increased with age. In contrast, the amplitude of the plasma melatonin rhythm at 2 days was already within the range of adults and did not increase with age. These results confirm and expand earlier findings in the European starling and parallel those from precocial birds indicating that the circadian system is already competent at or shortly after hatching even in atricial birds.     

Copper utilization during embryogenesis ofPalaemon lamarrei

Summary The pattern of copper utilization during the embryogenesis of the freshwater prawn,Palaemon lamarrei has been described. Throughout the incubation period, lasting for 14 to 16 days, the egg ofP. lamarrei is permeable to salts and against a concentration gradient, it absorbs 11 g of salt from the freshwater medium. Out of this total salt uptake, as much as 0.143 g is due to the absorption of copper. Intake of copper, as a function of incubation time, exhibited a more or less similar trend to that of total salt intake and this can be attributed to the increased synthesis of haemocyanin.     

Development of rhythmic melatonin synthesis in cultured pineal glands and pineal cells isolated from chick embryo

The chick pineal gland exhibits circadian rhythms in melatonin synthesis under in vivo and in vitro conditions. A daily rhythm of melatonin production was first detectable in pineal glands isolated from chick embryos at embryonic day 16 and incubated under a LD cycle. All pineal glands isolated from 17-day-old and older embryos were rhythmic while no gland isolated at embryonic day 14 and 15 exhibited a daily rhythm in melatonin synthesis. Melatonin production in static cultures of embryonic pineal cells was rhythmic over 48 h if the cells were kept under a LD cycle. When embryonic pineal cells were incubated in constant darkness the rhythm in melatonin production was damped within 48 h. These results suggest that chick pineal cells from embryonic day 16 onwards are photosensitive but that the endogenous component of the melatonin rhythm is not completely developed at that age. A soluble analogue of cAMP stimulated and norepinephrine inhibited melatonin synthesis in cultured embryonic pineal cells. These findings indicate that the stimulatory and inhibitory pathways controlling melatonin synthesis in the mature pineal gland are effective in pineal cells isolated from chick embryos at least 2 days before hatching.     

Imprinting of the Peking duck (anas platyrhynchos) and dependence on exposure to light during ontogenesis

Summary Embryos of Peking ducks were either incubated in complete darkness up to hatching or were put into light one week before hatching. Control embryos were incubated under dim light conditions which corresponded broadly to the natural conditions. Under standardized imprinting conditions the controls and both groups of the light deprived ducklings showed the following response. Most of the dark-incubated embryos, however, did not distinguish between imprinting and test objects of different shapes. Since most of the embryos kept in darkness only for 21 days also failed to develop the capacity for shape discrimination, there is apparently a, critical period for light influences on the development of this capacity at some time during the early prenatal period.Acknowledgments. We are grateful to Dr E. Pröve for his advice on the carrying out of our imprinting tests, to K. Weigel for help with the drawings and to Dr. J. R. Wolff for helpful discussions.     

Development of plasma cortisol in calves from birth to 14 days of age]

Plasma cortisol was recorded in 15 calves from birth to 14 days of age by a radio-immunoassay technique. At birth mean cortisol value is 67.3 ng/ml; 6 hrs. later it decreases by 58.4% then it gradually diminishes and about 14 days after, it reaches adult levels (5.1 ng/ml).     

Comparative ontogenesis of gamma-glutamyl transpeptidase in rat tissues

Summary In rats, placental gamma glutamyl transpeptidase (GGTP) specific activity declined linearly during the last third of gestation. In contrast, the kidney enzyme activity progressively increased 15-fold. In the gut, peak activity was reached at mid-lactation (age 12 days). Hepatic GGTP levels were maximal during the foetal stage. Brain GGTP was negligible at birth and attained its highest specific activity at weaning.This work was supported in part by USPHS NIH SO8 RR-09128-03.     

Lipid characterization and 14C-acetate metabolism in catfish taste epithelium

The catfish, Ictalurus punctatus is an important model system for the study of the biochemical mechanisms of taste reception. A detailed lipid analysis of epithelial tissue from the taste organ (barbel) of the catfish has been performed. Polar lipids account for 62 +/- 1% of the total, neutrals for 38 +/- 1%. Phosphatidyl-cholines, serines and ethanolamines are the major constituents of the polar fraction. Plasmalogen concentration is high relative to that of non-neural tissues. [14C]-Acetate is incorporated into cell lipid fractions after incubation of barbel tissue at 37 degrees C for 60 min. Percentage amounts of most lipids change with time during this in vitro incubation. The phospholipids are the most metabolically active fractions. This work yields information for continuing reconstitution experiments and indicates that the taste epithelium of this important model system is a metabolically active tissue capable of supporting lipid turnover/synthesis.     

In vivo perfusion of the human ovary with 4-14C-dehydroepiandrosterone and 7α-3H-dehydroepiandrosterone35S-sulfate. Biosynthesis of steroid hormones in human gonads,V

Zusammenfassung Nach in-vivo-Perfusion eines menschlichen Ovars mit 4-¹⁴C-DHEA und 7-³H-DHEA-³⁵S-sulfat lagen rund 15% der freien C₁₉- und C₁₈-steroide im Ovarialvenenblut als³H- und 85% als¹⁴C-markierte Verbindungen vor. Die Fraktion der sulfokonjugierten Steroide, bestehend aus 60% Steroidsulfatiden und 40% Steroidsulfaten, enthielt etwa 69% doppeltmarkierte, 27%³H- und 4%¹⁴C-markierte Sulfokonjugate. Neben dem vorzugsweise direkten Metabolismus des sulfokonjugierten DHEA liess sich auch ein indirekter Stoffwechsel zu Androgenen und Östrogenen nachweisen.

---

---

This investigation was supported by the Deutsche Forschungsgemeinschaft, 532 Bad Godesberg (Germany)     

Zur Konstitution des Resibufogenins und Artebufogenins

Summary The structure of Resibufogenin is unambiguously shown to be 3-hydroxy-14, 15-oxido-bufadien-(20, 22)-olide on the basis of new degradation work. Artebufogenin A and Artebufogenin B are 3-hydroxy-14-15-keto-bufadien-(20, 22)-olide and 3-Hydroxy-14-14-keto-bufadien-(20, 22)-olide, respectively.     

Inversion of the female sexual phenotype at high temperature in the urodelian amphibian, Pleurodeles waltii Michah]

Breeding of Pleurodeles waltii larvae with female gentotype was carried out in 29,5-30 degrees C tap water within 4 months after hatching. 11 out of 15, 1 year old animals, exhibited all the characteristics of male sexual maturity. Mating one of the neo-males (ZW) thus obtained, with a standard female (ZW) results in a sex-ratio of the offspring consistent with theoretical expectation.     

早期母子隔离应激对大鼠学习记忆能力的影响

目的探讨早期母子隔离应激对幼鼠学习记忆能力的影响。方法30只SD新生大鼠用于实验,实验随机分成3组,正常对照纽、母子隔离15分钟纽、母子隔离3小时纽。在生后40天,三组大鼠进行Morris水迷宫及记录海马脑片长时程增强电位（LTP）实验。结果Morris水迷宫测试,与正常组比较母子隔离3h组大鼠寻找平台需要的潜伏期延长（P〈0．05）,而母子隔离15分钟组大鼠寻找平台需要的潜伏期与正常组比较则无明显变化（P〉0．05）;海马脑片长时程增强电位提示：正常对照组条件刺激（CS）前后fEPSP斜率变化率为：64．7±22．9％;母子隔离3h组为：35．3±14．2％,低于正常组（P〈0．01）;母子隔离15min组为：66．3±29．7％,与正常组比较无显著性意义（P〉0．05）。结论幼鼠生后早期过度的应激导致大鼠的学习记忆能力减弱。