摘要:

AbstractBy means of a rapid microelectrophoretic technique suitable for single‐fly analysis, two types of alcohol dehydrogenase (ADH) isozyme patterns were found, each true breeding in homozygous stocks. A cross of these two types produces offspring with a third type of ADH pattern, containing hybrid ADH molecules in addition to the parental forms. Various strains were analyzed and found to contain flies of the three ADH types in various proportions indicating different gene frequencies.When octanol was used as a substrate instead of ethanol, an additional isozyme system was found, for which some strains are polymorphic also.The results obtained thus far are consistent with the assumption that ADH inDrosophilais a dime

ISSN:0022-104X    

DOI:10.1002/jez.1401600202

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

年代:1965

数据来源: WILEY

摘要:

AbstractAmounts of DNA per nucleus were estimated by microphotometry in Feulgen‐stained tissue sections from several species of poeciliid fish and their hybrid offspring. In terms of average nuclear volumes as well as relative DNA levels, the all‐female gynogenetic speciesP. formosawas indistinguishable from the related bisexual speciesP. sphenops, confirming the essentially diploid nature of the amazon molly,P. formosa. Although DNA values from the less closely related speciesP. vittatawere about 15% higher than those fromP. sphenops, both species showed expected patterns of DNA behavior in several somatic tissues and in developing male sex cells.Somatic nuclei from two types of interspecific hybrids contained more DNA than corresponding types of nuclei from typical maternalP. formosa, the additional amount being equivalent to the haploid DNA value characteristic of the participating paternal species. The results strongly suggest that these hybrids are genetic triploids, probably containing diploid maternal and haploid paternal chromosome contributions. The high incidence of chromosomal stickness, bridging, and fragmentation observed during metaphase I of spermatogenesis, and the occurrence of both “giant” and “micro” spermatids in testis of the hybridP. formosaXP. vittatamay well account for the apparent sterility of amazon molly offspring which show transmission of paternal characteristics.Production of triploid interspecific hybrids in poeciliid fish and corollary implications for interpreting previous tissue transplantation studies ar

ISSN:0022-104X    

DOI:10.1002/jez.1401600203

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

年代:1965

数据来源: WILEY

摘要:

AbstractFemale albino rats of a Wistar strain were exposed to either 135 r or 270 r of Co60‐radiation on the morning of day 11 (Witschi stage 17). Autopsy on day 20 revealed that the lower dose produced a slight increase in the degree of resorption, no effect on fetal weight and no malformations in the survivors. The higher dose, on the other hand, produced a large increase in the degree of resorption, a pronounced effect on fetal weight and many malformations.Radioactive phosphorus (P32) was injected into irradiated and non‐irradiated pregnant females to study DNA synthesis in individual litters after irradiation. Isotopically‐labeled DNA was extracted from embryo homogenates by a modified Schmidt‐Thannhauser procedure. DNA synthesis was suppressed in both series of irradiated embryos at 3, 6 and 12 hours after irradiation, the higher dose producing the larger amount of suppression. At 24 hours after irradiation, no significant difference was observed in the degree of DNA synthesis in control and irradiated embryos. No difference was observed between the specific activity of P32in the acid‐soluble fractions of placenta and embryo in control and irradiated litters, indicating that suppression of DNA synthesis reflected a change in the cellular population which is synthesizing DNA. Histological criteria indicate that this initial effect is cellular death and that the embryo compensates for this damage by regulatory

ISSN:0022-104X    

DOI:10.1002/jez.1401600204

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

年代:1965

数据来源: WILEY

摘要:

AbstractA series of experiments were designed to determine the origin of a nerve growth promoting protein found in high concentration in the tubular portions of the submandibular glands of adult male mice. This protein is necessary for the growth and development of immature sympathetic nerve cells. The quantities of this protein can be increased in the glands of female mice to levels found in the submandibular glands of adult male mice by injecting testosterone into preadolescent or adult female mice. When testosterone was given to young mice or to adult female mice together with an antiserum prepared against the nerve growth factor (NGF), the NGF content of the testosterone‐treated mice increased in the same manner as in testosterone‐ and normal serum‐treated mice. Although antiserum against the nerve growth protein could be demonstrated in the sera of mice during the course of the entire experiment, the antiserum had no effect on the content of NGF in the submandibular glands. After the intravenous injection of NGF in large quantities, it could not be localized in liver, spleen or submandibular gland cells of the mouse as determined by fluorescent antibody techniques. The results suggested that the nerve growth promoting protein found in high concentration in the submandibular glands of adult male mice and in testosterone‐treated female mice is synthesized and stored in cells of the tubular portion of these

ISSN:0022-104X    

DOI:10.1002/jez.1401600205

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

年代:1965

数据来源: WILEY

摘要:

AbstractPrelactating mammary tissues from five mammalian species (laboratory rat, guinea pig, hamster, rabbit, dog) were maintained in organ culture in the presence of insulin, corticoids and ovine prolactin (mammotropin — MH) and/or bovine growth hormone (somatotropin — STH). MH stimulated secretion in all but one species; however, any apparent secretory effect of STH could be accounted for by contamination with MH. Accordingly, these mammals did not demonstrate the interchangeability of MH and STH established for some mouse strains. There are species differences in mammary sensitivity to MH: dog and rabbit are most sensitive, hamster and rat are less sensitive, and guinea pig was unresponsive. No difference in response between Long‐Evans and Sprague‐Dawley rats was detected.Mammary tissues from the dog, guinea pig and rabbit showed some ability to survive in the unsupplemented synthetic medium “199” whereas tissues from the other two species showed little or no viability. Supplementation of the medium with insulin results in improvement in survival of mammary tissues from all species. The further addition of corticosteroid (aldosterone, cortisol or corticosterone) leads to greater augmentation of survival in tissues from all five species, with some indication that the gluco‐corticoid principally characteristic of the species concerned was more effective th

ISSN:0022-104X    

DOI:10.1002/jez.1401600206

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

年代:1965

数据来源: WILEY

摘要:

AbstractContinuous exposure to a high concentration of actinomycin D (250 μg/ml) completely inhibits oral regeneration in amputated tail pieces ofStentor coeruleus. Once oral regeneration is initiated, the same concentration of actinomycin D no longer inhibits normal regeneration. Concentrations of actinomycin which inhibit complete regeneration also inhibit incorporation of H3‐cytidine into RNA.Ribonuclease (1 mg/ml) completely inhibits normal oral regeneration in posterior pieces exposed continuously to this enzyme. Pretreatment of whole stentors with ribonuclease completely inhibits regeneration in cells exposed continuously for two hours but only partially inhibits it in cells exposed for shorter periods. During the same two‐hour period, cytoplasmic RNA is reduced to about a third its normal value. The results suggest that both newly formed (messenger?) and preexisting (ribosomal?) RNA are necessary for regeneration.During the last 3–4 hours of regeneration posterior pieces slough off developing oral anlagen as a result of addition of 1 mg/ml of ribonuclease. This sloughing of oral anlagen may indicate either a loss of RNA needed to maintain oral regeneration or a general response to

ISSN:0022-104X    

DOI:10.1002/jez.1401600207

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe red chromatophores ofUpogebia majorare concentrated by the injection of extracts from the sinus gland and the supraesophageal ganglia but not by the eyestalk extract. The former two cause dispersion of dark pigment ofIdotea japonicabut the eyestalk extract is ineffective. The sinus gland and the optic medulla lie in the cephalon. In the eyestalk, a structure is present which is considered to be homologous with the sensory pore x‐organ of macruran decapods. Evidence of secretory activity by certain cells in the sensory pore x‐organ has been addu

ISSN:0022-104X    

DOI:10.1002/jez.1401600208

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe possibility that an immunological tolerance of maternal skin homografts may be acquired naturally in guinea pigs as a consequence of the accidental incorporation of maternal cells into the fetuses has been re‐investigated. F1hybrids between two isogenic strains, 2 and 13, were reciprocally backcrossed to strain 13 animals to produce two genetically heterogeneous populations which differed only insofar as those animals which had developed in an F1hybrid uterine environment had had an opportunity to incorporate strain 2 cellular antigens ante partum.To test for any altered immunological reactivity this might have caused, both populations of animals were challenged with strain 2 skin homografts when they were 30 days of age. Although two of 192 offspring of F1mothers failed to reject their grafts during the 200 day observation period, the distribution of survival times of the remaining grafts in this group of animals was very similar to that of the grafts transplanted to 167 offspring of strain 13 females.It is concluded that the two exceptional cases are most probably the result of chance antigenic compatibility and that maternally acquired tolerance is a very rare phenomenon in guinea pigs, if it occurs at al

ISSN:0022-104X    

DOI:10.1002/jez.1401600209

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

年代:1965

数据来源: WILEY

摘要:

AbstractThis is the first of a series of studies on protein synthesis and its control during the molt cycle of the land crab,Gecarcinus lateralis. Incorporation of valine‐1‐C14and leucine‐1‐C14into proteins of blood, epithelium, midgut gland, and muscle has been measured at each stage and found to reach a maximum rate in all tissues during the stages D0through D2of the premolt period. This period is not necessarily the period of maximum net synthesis of total protein in all tissues. Total muscle protein, in fact, is decreasing at this time: the high incorporation rate may reflect synthesis of degradative enzymes.In control experiments on possible rate limiting features in amino acid incorporation, the pool sizes of valine and leucine in plasma water were determined. These do not vary systematically with stages in the molt cycle; the relatively small fluctuations in these pools do not correlate with the larger fluctuations in incorporation rate. The sizes of these pools do not appear to be rate limiting. In conjunction with these measurements, the plasma water volume ofGecarcinuswas found to be 22 ± 1.72 (S.D.) per cent of the body weight.It is also shown that the rate of penetration of amino acid from plasma water into intracellular water was not the rate limiting step in the incorporation of C14‐leucine into muscle protein. (Muscle is the tissue with the lowest incorporation rates.) Leucine penetrates muscle readily and appears to be concentrated four‐fold in muscle water relative to

ISSN:0022-104X    

DOI:10.1002/jez.1401600210

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

年代:1965

数据来源: WILEY

摘要:

AbstractPuromycin and ethionine immediately inhibit protein synthesis more than 90% in chemically dissociated sponge cells. Initial aggregation proceeds normally in the presence of both inhibitors, indicating that protein synthesis is not necessary for the aggregation of these cells. After six hours in puromycin, the cells stop aggregating and die. In ethionine, the cells aggregate and remain aggregated for at least 48 hours, although protein synthesis remains repressed. Thus protein synthesis is not necessary for producing the material which binds these cells together. Although the aggregation is not dependent on concurrent protein synthesis, it was conceivable that protein which was stored in the cell was secreted during aggregation. However, sponge cells could aggregate over and over in ethionine, indicating that the cells were not dependent on a stored supply of material.

ISSN:0022-104X    

DOI:10.1002/jez.1401600211

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

年代:1965

数据来源: WILEY