PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. XII. THE METABOLISM AS A FUNCTION OF AGE.

1. The previous findings that the rate of metabolism per gm. of body weight decreased with age, and that during the incubation period catabolism was mostly at the expense of fat, have been confirmed. 2. These determinations of the rate of oxygen uptake have afforded more precise values for the catabolic rate and thus permit estimations of the changes with age in the rate of absorption.     

PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. IX. THE IODINE REACTION FOR THE QUANTITATIVE DETERMINATION OF GLUTATHIONE IN THE TISSUES AS A FUNCTION OF AGE.

The iodine reaction to determine—SH groups in tissues according to the technique of Tunnicliffe showed that the percentage concentration of such compounds in the dried substance of chicken embryos declines with age chiefly during the third quarter of the incubation period.     

PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. XIV. THE HYDROGEN ION CONCENTRATION OF THE BLOOD OF CHICKEN EMBRYOS AS A FUNCTION OF TIME.

We have studied by means of glass electrodes the hydrogen ion concentration of the blood of chicken embryos from 8 to 20 days. When plotted as a curve, the average data show that a constant change takes place in the measurement, being acid at the beginning of this period and becoming alkaline toward its end. The acid reaction we think was characteristic not only of the embryos of fowl, but of the fetuses of cats and indeed as Warburg has shown of rapidly growing tissue in general. We have suggested the possibility, though we have no data to substantiate the suggestion, that the hydrogen ion concentration may under conditions like these, seeing that the curve of change resembles that of oxygen consumption, be expressive of changes in the rate of metabolism.     

PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. VIII. ACCELERATIONS OF INTEGRATION AND DIFFERENTIATION DURING THE EMBRYONIC PERIOD.

The chief results of the studies here reported have been (1) the correlation between growth as a whole and the differentiation of gross form (primary redistributions or simple evolution), and (2) the correlation between internal integration or concentration and the differentiation of chemical form (secondary redistributions or compound evolution). With the latter are also associated the catabolic rate and the latent period or reaction time after implantation in plasma as demonstrated in tissue culture experiments. Moreover, it has been shown that these two chief developmental processes occur at different rates, and that they undergo their greatest changes in rate at different periods of embryonic life. Corresponding with Robertson''s growth acceleration periods there may be three cycles or rhythms of which the embryonic phase is the first, each composed of a period of growth followed by a period of differentiation. This conception is somewhat analogous to Roux''s notion of dividing the life span into two chief periods (1) embryonic for the growth of organ rudiments and (2) post-embryonic, characterized by functional development. The first period of total growth and form differentiation seems to cover the time when the main, but bare, outline or scaffolding of the organism is laid down. The second period, correlated as it is with catabolism (function), corresponds, not in time but as a phenomenon, with Roux''s period of functional form development.     

PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. XIII. THE TEMPERATURE CHARACTERISTIC FOR THE CONTRACTION RATE OF THE WHOLE HEART.

The relation of heart rate frequencies to temperature in intact chicken embryos has been studied and the temperature characteristics calculated for each of a number of ages. These have been found to vary from 14,000 or better 12,000 µ for embryos 3 days old, to about 6,000 µ for others of 15 days. There appears to be a systematic change with time. If this inference is correct, important correlation with other properties of the pace-making function in the intact heart should become possible.     

PHYSIOLOGICAL ONTOGENY : A. CHICKEN EMBRYOS. X. THE TEMPERATURE CHARACTERISTIC FOR THE CONTRACTION RATE OF ISOLATED FRAGMENTS OF EMBRYONIC HEART MUSCLE.

1. The Arrhenius equation giving the relationship between the velocity of chemical reaction and temperature, was found suitable for the special case of the contraction rate of embryonic heart muscle fragments. 2. There was no constancy in the values of µ for the rate of contraction in culture, nor was the scattering evenly distributed around certain (more than one) points. 3. There seemed to be no correlation between µ and other functions such as the contraction rate, the site from which the piece was removed, the age of the embryo, etc.     

THE EFFECT OF AGE, GROWTH RETARDATION AND ASPHYXIA ON ASCORBIC ACID CONCENTRATIONS IN DEVELOPING BRAIN

Abstract— The concentration of ascorbic acid in whole rat brain during the first week of postnatal life was up to 100 per cent higher than in adult animals. A progressive fall in concentration occurred between 4 and 30 days of age. Corresponding changes did not occur in liver and adrenal gland, two other organs rich in ascorbic acid. Rats subjected to growth retardation during the fetal and suckling periods had, at 25 days of age, levels of ascorbic acid in the cerebellum and brainstem significantly higher than those of control animals. A period of prolonged asphyxia in 5-day-old rats resulted in a significant 4 per cent reduction in whole brain ascorbic acid concentration.     

THE ANTAGONISM BETWEEN ACETIC ACID AND THE CHLORIDES OF SODIUM,POTASSIUM, AND CALCIUM AS MANIFESTED IN DEVELOPING FUNDULUS EMBRYOS

1. Developing Fundulus embryos react in much the same way to mixtures of acetic acid in salt solutions whether their membranes are removed or not. It is therefore not necessary to assume any specific rôle for the membrane. 2. The primary toxic effect of acetic acid is to kill the surface of the embryo; heart stoppage is due to penetration of the acid after the surface has been injured. 3. The salt (NaCl, KCl, CaCl₂) antagonizes the acetic acid by slowing or preventing the killing of the surface of the embryo. 4. If embryos are immersed in certain KCl-acetic acid mixtures, the surface killing effect of the acid is antagonized but at the same time the KCl penetrates and stops the heart in the manner which is characteristic of a KCl solution alone.     

NATURE OF THE INHIBITION OF PROTEIN SYNTHESIS BY ETHIONINE AND AMINO ACID UPTAKE IN EARLY SEA URCHIN EMBRYOS

The inhibition of protein synthesis by ethionine reported previously was found to be apparent, and ethionine inhibited only amino acid uptake like other usual amino acids. Even under such strong inhibition of the uptake, the syntheses of protein and DNA remained almost undiminished. The uptake of amino acid mixture by sea urchin embryos in the early cleavage stage was found to be carried out by active transport, since it was temperature-sensitive and was inhibited by 2,4-dinitrophenol. The uptake of an amino acid mixture or of single amino acids, e.g., valine, leucine and phenylalanine, was inhibited nonspecifically by an excess amount of other single amino acids added exogenously. Reflecting the inhibition of amino acid uptake, in vivo incorporation of amino acids into the protein fraction was apparently inhibited by excess amounts of other amino acids. As far as tested, the inhibition seems to be nonspecific and competitive for all amino acid species. The uptakes of leucine and phenylalanine were inhibited mutually by competition, with almost the same Km and Ki.     

INDEPENDENCE OF TISSUES DERIVED FROM APICAL LAYERS IN ONTOGENY OF THE TOBACCO LEAF AND OVARY

Six different homoplastidic periclinal chimeras of tobacco carrying the plastogene DP₁ were selected after somatic segregation in heteroplastidic seedlings. Direct observation of the plane of division in epidermal cells of young leaves, and the number and size of sub-epidermal green spots on leaves with the Green-White-White (G-W-W) pattern of variegation, indicated that the ratio of periclinal to anticlinal divisions in L-I during development of the lamina was 1:3100. The number of green and white seedlings obtained from the different chimeral branches indicated a similar frequency of periclinal divisions in development of the ovary. The arrangement of green and white tissue in mature leaves of the various chimeral types indicated the extent of participation by the three apical layers in the initiation of the buttress, development of the axis, and formation of the lamina. During development of the lamina there must be three independent initial-groups present. L-I and L-II initials remain marginal, but early in the growth of the lamina the leading edge of tissue derived from L-III becomes separated from the submarginal (L-II) initials by the products of frequent periclinal divisions of the L-II initials.     

ONTOGENY OF CHICKEN HEMOGLOBIN. III. IMMUNOLOGICAL STUDY OF THE HETEROGENEITY OF HEMOGLOBIN IN DEVELOPMENT

By applying the double diffusion technique of Ouchterlony and the immunoelectrophoresis, sequence in the appearance of antigens reactive with antisera against HbCOs from 5-day embryos and adult chickens, and the major component of adult HbCO in the course of chicken development has been studied.
Antigenic components reacting to antiserum against HbCO from 5-day embryos have been detected throughout development. Three globin-like components specific to early embryos are detectable in embryos to 2 days of incubation. Two Hb components are detectable in embryos from 3 to 5 days of incubation; one is apparently specific to embryos, while the other seems to be somewhat different from adult Hb. After 6 days of incubation only one adult Hb component is detectable.
Antigenic components reacting to antiserum against HbCO from adults have also been detectable throughout embryonic life. One globin-like component specific to early embryos can be found in embryos to 2 days of incubation. One or two Hb components which are probably specific to embryos can be detected in embryos from 3 to 5 days of incubation. After 6 days of incubation one adult Hb component is detectable, while one globin-like component specific to adults can be found after 15 days of incubation. Further, the other globin-like component is detectable after 3 days of incubation.
Antigenic components reacting to antiserum against the major component of adult HbCO have been detected throughout development; one which seems to be somewhat different from either adult Hb components can be found in embryos from 2 to 5 days of incubation, while the other which is identical with the major component of adult Hb is detectable after 6 days of incubation.     

ONTOGENY OF CHICKEN HEMOGLOBIN. I. ELECTROPHORETIC STUDY OF THE HETEROGENEITY OF HEMOGLOBIN IN DEVELOPMENT

Separation of different molecular species of hemoglobin from developing chickens by starch gel electrophoresis has revealed the appearance of early embryonic (embryonic), late embryonic (fetal) and adult hemoglobin (Hb) type during development. In 5-day embryos, there are 3 or 4 forms of embryonic Hb type. They begin to decrease in 6-day embryos and cannot be detected in embryos after 10 days of incubation. In 6-day embryos, two forms of adult Hb type appear, and one of them, which is a major form in adults, becomes t o be a major one in 7-day embryos. One or two forms of fetal Hb type first appear in 10-day embryos and are still present in 5-day posthatching chickens.
Ultracentrifugation of carbonmonoxyhemoglobins from embryos at early and at later stages (fetuses), from newly hatched and from adult chickens has shown that they have a single monodisperse peak. Some heterogeneity, however, has been detected after starch gel electrophoresis, probably owing to aggregation or polymerization.
Subunit analysis of embryonic, fetal and adult Hb type by starch gel electrophoresis in formate buffer at pH 1.9 has indicated that embryonic Hb type contains total 5 subunits, C, D, E, F and G; fetal Hb type, total 2, A and H; and adult Hb type, total 3, B, F and H.     

ONTOGENY OF CHICKEN HEMOGLOBIN II. CHROMATOGRAPHIC STUDY OF THE HETEROGENEITY OF HEMOGLOBIN IN DEVELOPMENT

Some properties of the carbonmonoxyhemoglobin (HbCO) from chicken embryos of ages 5, 10 and 15 days of incubation, from 1-day posthatching and from adult chickens have been investigated by chromatography on carboxymethylcellulose (CM-cellulose) column and by starch gel electrophoresis.
Chromatogram of the hemoglobin (Hb) from 5-day chicken embryos has shown that it consists of at least 6 components. Starch gel electrophoresis of each isolated component from the column in phosphate (pH 6.8), in borate (pH 8.6) and in formate buffer (pH 1.9) has shown later that there are 3–4 embryonic type Hb components in 5-day embryos.
Chromatogram of the hemoglobin from adult chickens has shown that it consists of at least 4 components, but the examination of each isolated component from the column by electrophoresis in phosphate (pH 6.8), in borate (pH 8.6) and in formate buffer (pH 1.9) has shown that there are 4–6 adult type Hb components in adults.
In ontogenic process, embryonic Hb type is detectable in embryos up to 15 days of incubation. Fetal Hb type, which is not detectable in adult chickens, can be first found in 10-day embryos.     

POSTNATAL CHANGES IN FREE AMINO ACID,DNA, RNA AND PROTEIN CONCENTRATIONS OF MINIATURE SWINE BRAIN1

Postnatal developmental characteristics of miniature swine brain were evaluated through the first 9 weeks of age. Differential growth rates of cerebrum, cerebellum and brain stem were defined in terms of DNA, RNA, protein and free amino acid concentrations at ages 5, 21, 35 and 63 days. Within the experimental conditions provided, hyperplasia ceased just prior to ages 21, 35 and 63 days for cerebellum, brain stem and cerebrum, respectively. An additional cerebral growth spurt, observed between weaning at age 35 days and sacrifice at age 63 days, may be indicative of impaired brain development due to inadequate nutrition provided by the dam's milk. Developmental changes in mean concentrations of brain free amino acids varied with anatomical area and differed somewhat from those of other species previously reported. For example, mean cerebral concentrations of aspartic acid, γ-aminobutyric acid and asparagine + glutamine decreased significantly (P < 0·05) with age and mean glutamic acid concentration was 5 times that of taurine.     

热性发热兔血浆脂多糖（LPS）浓度与生理反应的变化

在干球温度４２℃、湿球温度３５℃、相对湿度６０％条件下,测定了２４只热暴露兔［分为肛温维持４３℃（Ⅰ）组和肛温持续上升（Ⅱ）组］的心率、平均动脉压、呼吸频率、肛温及血浆ＬＰＳ浓度等指标。结果显示：（１）Ⅰ、Ⅱ组当Ｔｒ升达４３℃,热暴露时间分别为１００ｍｉｎ、６０ｍｉｎ时,血浆ＬＰＳ浓度分别为０．１９５ｎｇ／ｍｌ、０．１８０ｎｇ／ｍｌ,与实验前比,Ｐ＜０．０５。两组临死前,热暴露时间分别为２２０ｍｉｎ、１２０ｍｉｎ（Ⅱ组Ｔｒ４４．１５℃）时,其血浆ＬＰＳ浓度分别为０．２８５ｎｇ／ｍｌ、０．２４９ｎｇ／ｍｌ,Ｐ＜０．０１;（２）Ｔｒ４３℃和临死前两阶段ＬＰＳ的上升速率,Ⅰ组分别为０．０００６６ｎｇ／ｍｉｎ和０．０００６７ｎｇ／ｍｉｎ,Ⅱ组分别为０．０００８３ｎｇ／ｍｉｎ和０．００１１３ｎｇ／ｍｉｎ;（３）动物受热过程,Ｔｒ升至４３℃时,ＨＲ和ＭＡＰ达峰值水平,而呼吸频率则开始下降。本文结果提示,ＬＰＳ在中暑的病理生理学过程中可能是一个值得重视的因素     

ENZYMES OF THE TRICARBOXYLIC ACID CYCLE IN SEA URCHIN EGGS AND EMBRYOS

Changes in the activity of some enzymes of the tricarboxylic acid cycle during development of sea urchins were investigated. Unfertilized eggs showed substantial activity of citrate synthase, aconitase, NAD- and NADP-specific isocitrate dehydrogenases, fumarase and malate dehydrogenase. During development, the activity of citrate synthase, aconitase, NADP-specific isocitrate dehydrogenase and malate dehydrogenase increases gradually, whereas the activity of fumarase remains rather constant. There is no close correlation between changes in the enzyme activity and the increase in oxygen consumption during development. Citrate synthase, aconitase, NADP-specific isocitrate dehydrogenase are mainly localized in the mitochondrial fraction, whereas fumarase and malate dehydrogenase are present in both mitochondrial and cytosol fractions. The intracellular localization of these enzymes does not change during development. A possible mechanism for the regulation of some enzymes of the tricarboxylic acid cycle in sea urchin eggs is discussed.     

陕南寒武系底部保存精美的Punctatus胚胎及孵化幼体化石(英文)

在陕南寒武系底部的宽川铺段不仅保存了大量的小壳化石,而且还有诸多后生动物的卵和胚胎化石。目前,大量的胚胎化石已被报道,但是对古老的后生动物早期的个体发育却鲜有报道,尽管Bengtson和Yue(1977)建立了Olivooides的发育序列,但仍缺少一些重要的中间环节,而且胚胎的早期卵裂阶段还不是很清楚。因此,Olivooides和Punctatus之间的联系很难确立。本文报道了宽川铺生物群中新发现的精美的Punctatus的卵裂期、囊胚期及孵化幼体阶段的胚胎化石标本,这些新发现不仅填补了Punctatus发育序列中的空白,而且揭示了Olivooides和Punctatus之间的联系。这些新收集的Punctatus的卵裂期和孵化期的化石特征及Punctatus的形态学证明了Punctatus不是浮游生物,而是底栖生物。大量的胚胎化石和Punctatus的孵化幼体化石标本为我们研究后生动物早期演化提供了线索。