摘要:

AbstractA method is presented for the isolation of mitochondria with good respiratory control from the hepatopancreas of the marine clamMercenaria mercenaria.Palmitoyl‐L‐carnitine is the preferred substrate of the mitochondria of the hepatopancreas based on state 3 rates of oxidation (in the presence of ADP). Rates of oxidation of pyruvate and glutamate were about one‐half that of the lipid substrate in state 3. α‐Glycerophosphate was oxidized at a rate about one‐third that of palmitoyl‐L‐carnitine. All Krebs cycle intermediates were oxidized to some extent. Proline was not oxidized at detectable levels. The optimal range of KCI concentrations for the oxidation of palmitoyl‐L‐carnitine is between 250 and 500 mM whereas the optimal range of KCI concentration for the oxidation of succinate is between 200 and 350 mM. The optimal range of pH for the oxidation of succinate and for the oxidation of palmitoyl‐L‐carnitine lies between pH 6.5 and 7.5 based on the res

ISSN:0022-104X    

DOI:10.1002/jez.1402300202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractA cell‐free system, active in protein synthesis, was constructed using ribosomes and supernatant factors isolated from the livers of winteracclimatized carps. Upon seasonal adaptation, the hepatocytes of these fishes exhibited distinctive morphological features that were not sex dependent. The cytoarchitecture of the liver cell from summer carps is consistent with the cellular arrangements found when the rate of gene expression is high. During winter, several morphological features reveal that macromolecular synthetic activity may be clearly diminishe

ISSN:0022-104X    

DOI:10.1002/jez.1402300203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractMale and female winter‐acclimatized carps were injected with insulin. This treatment resulted in a sharp decrease in the liver glycogen content. Although an increase in the ribosomal RNA level was also observed, a cell‐free system obtained from the hormone‐treated fish exhibited less amino acid incorporation activity as compared to the control fish. However, polysomes from insulin‐treated fish exhibited a higher amino acid incorporating activity when a soluble fraction of untreated winter carps was used.Insulin induced a profound change in the cytoarchitecture of the winter carp hepatocyte. The cytoplasm and nuclei showed all the features of the summer carp liver cell. The nucleolar components were totally intermingled suggesting a high rate of gene expression as in the case of the summer‐acclimat

ISSN:0022-104X    

DOI:10.1002/jez.1402300204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractOlfactory stimuli are sufficient for detection and discrimination of sex of conspecific lizards by the male broad‐headed skink,Eumeces laticeps, a member of a large group of lizards with pronounced chemosensory abilities, the Autarchoglossa.The capacity of male broad‐headed skinks to detect conspecific odors was assessed by measuring tongue extrusion rates in response to odor stimuli presented on moist cotton applicators. Tongue‐flick rates of postreproductive males were siginificantly higher for clocal odors of postreproductive conspecif‐ics of both sexes than to distilled water and higher to female than male odors over the initial 20‐ and 60‐sec intervals. In a second experiment using testosterone‐treated males and estrogen‐injected females, testosterone‐treated males emitted significantly more tongue flicks to female cloacal odors than to the other stimuli, and two males bit applicators bearing male odors. Testosterone did not affect reaction to male cloacal odors, but markedly increased tongue flick rates in response to cloacal odors of estrogen‐treated females. Post reproductive males also responded to female, but not male, skin odors at a significantly higher rate than to water. Possible sources and presumed adaptive significance of conspecific

ISSN:0022-104X    

DOI:10.1002/jez.1402300205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractContractile vacuole function in amoebae treated with immobilizing (5 mM) and nonimmobilizing (0.125 mM) concentrations of ATP has been studied. In ATP‐immobilized amoebae, most vacuolar parameters are accelerated, especially the rate of output which passes from 30 to 70 μm3/sec. This favors the concept of an autonomous vacuole, fully functional in the absence of any bulk contribution to it from remote points of the cell. A lower concentration of ATP (0.125 mM), which does not inhibit movement, causes a still greater acceleration of vacuolar function. Work is in progress to elucidate the site and mode of action of exogenous ATP onAmoe

ISSN:0022-104X    

DOI:10.1002/jez.1402300206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractThe development of amphibian sensory systems and behavior is generally considered to proceed normally without reference to sensory experience during embryonic or larval stages. Most of the supporting research, however, has concentrated on the retinotectal (visual) systems of anurans and has ignored behaviors directed by other sensory systems. We demonstrate that early exposure to light is necessary for the development of photopositive behavior inXenopus laevistadpoles, a behavior probably directed by the pineal complex. Light‐deprivation during the tadpoles' first 10 days of development results in a long‐lasting reduction in the tadpoles' light preference. The development of a strong light preference is not influenced by light‐deprivation before the tadpoles are 2 days old or after the tadpoles are 10 days old, but light‐deprived tadpoles recover a weak light preference after subsequent days of rearing in the light. Lengthening the tadpoles' exposure to light during the first 10 days of development produces increasingly strong light preferences. Considering the important role of the pineal complex in guiding phototactic behaviors in anurans, we suggest that light‐deprivation alters photopositive behavior inXenopustadpoles by altering the development of the pinea

ISSN:0022-104X    

DOI:10.1002/jez.1402300207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractIn the Silkie fowl large numbers of melanocytes invade most internal tissues and organs. The factors involved in this internal pigment cell pattern were studied by grafting quail neural tube segments into White Leghorn, White Silkie, and F1hybrids (White Silkie male × White Leghorn female). Sections of quail neural tube five somites long, excised at the level of the last formed somites, were grafted isotopically and isochronically. Various tissues and organs (mesenteries, muscles, testis, ovary, mesonephros, metane‐phros, and adrenals) excised from the internal region corresponding to the peripheral transverse strip of quail melanocytes, were studied after staining by the Feulgen‐Rossenbeck technique.Despite some variations in pigment cell density, Silkie and hybrid grafted embryos exhibited an extensive quail internal pigmentation similar to the melanocyte distribution in the Silkie breed. In white Leghorn host embryos, the internal pigmentation remained limited. These results show the part played by tissular factors in the expression of the Silkie pigment phenotype and that this genetic tissular character is dominant.On the contrary, White Leghorn embryos, grafted with Silkie neural tube segments, never exhibited any internal pigmentation; the melanocytes deriving from the grafted Silkie neural tube were only localized at the dermoepidermal level. Thus, the migrating and/or differentiating capabilities of the Silkie premelanoblasts are different from those of quail premelanoblasts. The sex‐linked inhibitor of the White Leghorn tissue interferes at the level of the pigment cells of chickens but not of

ISSN:0022-104X    

DOI:10.1002/jez.1402300208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractNeuronal cell death has been postulated to occur as a consequence of there being a limited availability of target. This hypothesis was examined by delaying the onset of motoneurone cell death, by temporary paralysis of chick embryos, until the size of the target had increased. Despite the availability of this enlarged periphery, the extent of cell death was unaltered, although the rate of cell death was retarded. It is argued that the extent of cell death is not simply related to target size and may instead be governed by differences in the capacity of particular motoneurones to compete successfully for target cells.

ISSN:0022-104X    

DOI:10.1002/jez.1402300209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractA technique for the culture of 12‐ and 13‐day rat embryos is presented. The culture method described utilizes the opening of the extraem‐bryonic membranes together with a simple bottle rotator during incubation to facilitate tissue oxygenation. This method was compared with a more elaborate device that enabled constant gassing during incubation. Best results were obtained with 12‐day embryos cultured for 24 hr in closed bottles. Thereafter, there was a marked falloff in embyronic development in culture. Optimal medium conditions were 25% rat serum in tissue culture medium with a gas phase of 60% O2, 5% CO2, 35% N2. The culture method described allows for larger numbers of embryos to be cultured more simply than previous methods and should be valuable to workers wishing to study embryos in the more advanced stages of organo

ISSN:0022-104X    

DOI:10.1002/jez.1402300210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractWe have used a mouse cell transformant generated by human chromosome‐mediated gene transfer (CMGT) to explore the use of cell surface antigens in the identification of fragments of human chromosomes retained by somatic cell hybrids. The transformed line, 21–30b, contained an intact rearranged human chromosome, and could be shown by isozyme analysis to contain genetic material from chromosomes 9 and X. By using the transformant as an immunogen in mice, it was also possible to produce antiserum to human‐specific surface antigens. Using genetically characterized human × rodent hybrid lines, the genes controlling expression of these antigens could be localized to 11pter → 11p13, segregating concordantly with surface antigen S3. These conclusions were possible despite the fact that the presence of chromosome 11 in the transformant was not detectable by the presence of chromosome specific isozyme LDH‐A or surface antigens W6/34 and 4F2. Finally, the fluorescence‐activated cell sorter (FACS) was used to fractionate the transformant cells into antigen positive and negative subpopulations. This resulted in the isolation and characterization of four additional chromosome rearrangements involving interspecies chromosome translocations. This work demonstrates the value of chromosome‐specific surface antigens and the FACS in the evaluation of human chromosome fragments retained by inters

ISSN:0022-104X    

DOI:10.1002/jez.1402300211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY