摘要:

AbstractThe recessive mutant gene short‐ear (se) reduces the rate of proliferation of precartilage cells, producing a skeleton of reduced size with numerous small defects. It also reduces the rate of proliferation of callus cells in healing bone fractures. In this studysewas shown not to affect rate of regeneration of liver, thymus, or connective tissue.Short‐eared mice have many anatomical abnormalities of the soft tissues including medial displacement of the left gonad, ventral displacement of the right renal artery, hydroureter and hydronephrosis, giant cell granulomas on the ventral surface of the liver, and on some genetic backgrounds an increased frequency of cysts of the lungs. Youngse/semice often have neuromuscular waviness of the tail. In the heterozygous condition (+/se) the gene causes a slight reduction in skeletal size and a slight increase in frequency of hydroureter, liver lesions, lung cysts, and wavy tail. It was shown that the viscera appear to be crowded from the 11‐day stage of gestation and that crowding is probably responsible for the abnormalities of the left gonad, the right renal artery, and the ureter, and is possibly a contributing cause of the granulomas of the liver. The probable cause of the crowding is the slower growth of the skeleton, resulting in a body cavity too small to accommodate the visceral mass of normal size. It is not clear that crowding is a sufficient explanation of the liver lesions or that it explains the effect ofseon frequency of lung cysts or on waviness of the

ISSN:0022-104X    

DOI:10.1002/jez.1401670202

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

年代:1968

数据来源: WILEY

摘要:

AbstractCytological studies of ovaries fromDrosophila melanogasterhomozygous for the female sterile gene,su2‐Hw, demonstrate that the nurse cell components of the egg chambers are primarily affected. The chromosomes of these endopolyploid cells remain condensed, whereas the normal polytene chromosomes of wild type nurse cells uncoil and fall apart prior to vitellogenesis. Vitellogenesis is greatly inhibited in the mutant, and the egg chambers eventually degenerate. Reciprocal transplantation experiments show autonomous behavior of + andsu2‐Hwovaries. Therefore the ovarian phenotype is due to the action of the mutant gene in the ovarian cells themsel

ISSN:0022-104X    

DOI:10.1002/jez.1401670203

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

年代:1968

数据来源: WILEY

摘要:

AbstractIntact and hypophysectomized larvae ofAmbystoma maculatum, A. opacum, A. lateraleandA. mexicanumwere subjected to the influence of adult newt (Notophthalmus viridescens) pituitary hormones by means either (1) of adenohypophyseal implants to the lower jaw or, (2) daily intraperitoneal injections of ACTH. After a 10–21 day treatment period, the ecotopic newt pituitary was removed or the ACTH injections were terminated. Neither procedure had any consequence for limb regeneration, whether limbs were amputated during, or from two to five days following cessation of, hormone treatment. The positive regenerative response suggests that limb tissues of larvalAmbystomado not respond either directly, or indirectly via the adrenal cortex, to the ectopic adult newt pituitary or to ACTH injection. Implanted adult newt pituitaries were found to cause precocious metamorphosis inA. maculatum, A. opacum, andA. lateralebut not inA. mexicanu

ISSN:0022-104X    

DOI:10.1002/jez.1401670204

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

年代:1968

数据来源: WILEY

摘要:

AbstractRabbit antisera against red blood cells from three‐day‐old chickens, absorbed with adult chicken red blood cells, identify an antigen on the red blood cells of young chickens that is not detectable in adults. The antigen is present on all red blood cells at hatching. Approximately 50 days after hatching, cells with the antigen start to disappear and are completely undetectable by 120 days. Studies aimed at elucidating the mechanism of the developmental antigenic change suggested that the antigen or a component of the antigen is lost during development rather than being coated by a serum component or embedded in the red blood cell membrane. Various experiments were performed in an attempt to alter the proportion of cells carrying the anti

ISSN:0022-104X    

DOI:10.1002/jez.1401670205

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

年代:1968

数据来源: WILEY

摘要:

AbstractIn chicks between the day of hatching and ten days after hatching the body temperature was lowered from normal to either 34°C or 24°C. Oxygen was then replaced by nitrogen until breathing ceased and the electroencephalograms of the cerebral lobes were reduced to no difference of potential. When this zero potential had endured for a period four times as long as that which yielded about 50% recovery in one to ten day chicks at normal body temperature, artificial ventilation was applied for a maximum of eight minutes or until the onset of spontaneous breathing. This four fold duration of zero potential was: 12 minutes for newly hatched and one day chicks, six minutes for five day chicks, and four minutes for ten day chicks. A withholding of artificial respiration for these prolonged periods of zero potential resulted in the following percentages of recovery: at normal body temperatures, 0%; at 34°C and 24°C respectively, newly hatched chicks 23% and 90%, one day chicks 10% and 40%, five day chicks 40% and 70%, ten day chicks 80% and 90%. Prior to artificial resuscitation birds had electrocardiograms indicating irregular beats, various degrees of heart block, and cardiac arrest for as long as seven minutes; some of these recovered. The transition of the electroencephalogram from zero potential to normal EEG patterns was characterized by a gradual increase in amplitude of both slow and fast waves in the younger chicks and a kind of steplike recovery in the older birds. During recovery about 50% of the younger chicks showed seizures resembling “petit mal”. After a recovery period of 4 to 24 hours the surviving chicks showed no behavioral abnorm

ISSN:0022-104X    

DOI:10.1002/jez.1401670206

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

年代:1968

数据来源: WILEY

摘要:

AbstractSpleens obtained from the common snapping turtle,Chelydra serpentina(Linné), have been analyzed for immunological competence in severalin vitrosystems. Spleen fragments can be maintained in tissue culture for several weeks under conditions permitting antibody formation. Such fragments can produce specific agglutinins to sheep or mouse red blood cells when presented with these antigensin vitro.Cells obtained from adult turtle spleens can elicit splenomegaly or hepatomegalyin vitroin a manner suggestive of a graft‐versus‐host reaction. Using thesein vitroprocedures, it has been observed that maturation of the immunological system of the turtle occurs several months after hatching, and that hibernating turtles are defective in immunological capacity. Histological studies indicate that the snapping turtle has cloaca‐associated lymphoid tissues similar to the bursa of Fab

ISSN:0022-104X    

DOI:10.1002/jez.1401670207

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

年代:1968

数据来源: WILEY

摘要:

AbstractA femaleRana pipiens sphenocephalasuspected of being heterozygous at a locus specifying the B or most negatively charged, subunit of the lactate dehydrogenase isozymes was back‐crossed to aR. p. sphenocephalamale and outcrossed to aR. p. pipiensmale. The results of these crosses show that: (1) the structure of the B subunit of frog LDH is controlled by at least three allelic genes (LDBa, LDBb, and LDBc; (2) LDH of the offsprings' phenotype appears before hatching; (3) maternal‐type enzyme, probably synthesized during oogenesis, persists until at least the eleventh day after the tadpoles begin to f

ISSN:0022-104X    

DOI:10.1002/jez.1401670208

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

年代:1968

数据来源: WILEY

摘要:

AbstractCytometric analysis was made on the adult adipose tissue of sectioned abdomens of normal and experimentally treated adultDrosophila melanogaster. The adipose cells of two week old males and females are equal in size. The male cells contain 72% glycogen and 7% lipid, whereas the female cells contain 60% glycogen and 23% lipid. The adipose tissue of males containing a mature, transplanted ovary is similar to the female adipose tissue with regard to the cell size and amounts of lipid and glycogen. The adipose cells of castrated females are about 1.4 times larger than those of normal females, but the amount of lipid and glycogen per cell remains somewhat feminine. The adipose cells of genetically sterile,fes, females are about 1.4 times larger than those of normal females, but the amount of lipid and glycogen per cell remains somewhat feminine. The adipose cells of genetically sterile,fes, females are about 1.5 times larger than normal cells and are similar to normal male cells with regard to the proportions of reserve substances. The adipose cells offesfemales containing a transplanted, normal ovary shrink to the same size as those of normal flies; and are similar to those of the normal females with respect to amount of glycogen, but are similar to those of normal males with respect to the amount of lipid. The ovary's stimulatory effect on the growth of the larval and repressive effect on the growth of the adult tissue is discussed.

ISSN:0022-104X    

DOI:10.1002/jez.1401670209

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

年代:1968

数据来源: WILEY

摘要:

AbstractParamecium aureliahas been exposed to varying concentrations of actinomycin D for extended periods and to a high concentration starting at various specific times in the cell cycle. Extended exposures at 5 μg of actinomycin per 1.0 ml of culture medium are lethal as are 24 hour exposures at 20 μ/1.0 ml. Exposures initiated at selected times in the interfission period reveal transition and stabilization points, similar to those found inTetrahymena, that is, exposure prior to the transition point almost invariably blocks a given developmental event. Exposure after the transition point may or may not result in blockage but exposure after the stabilization point typically never shows blockage. Also the normal sequence of developmental events can be upset by exposure to actinomycin. These results are interpreted as being consistent with sequential action of the genes in the cell cycle and as indicating independence of final genetic control of different developmental processes, though all processes are dependent on common prior events. The macronucleus of exposed cells shows aggregation of dark material that is neither DNA nor RNA, and is probably a protein, but whose normal function is not know

ISSN:0022-104X    

DOI:10.1002/jez.1401670210

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

年代:1968

数据来源: WILEY

摘要:

AbstractPolar granules ofDrosophilashow distinctive variations in structure at various stages of early embryogenesis and in different species. In most species they are attached to mitochondria at fertilization, then they become free and fragment during the cleavage divisions and during the time of pole cell formation. After pole cells have formed they again coalesce. At the time of migration of the pole cells to the embryonic gonad, the polar granules again fragment and become attached to the outer membrane of the nuclear envelope.Ribosomes are attached to the periphery of polar granules at the time they are fragmented prior to and during pole cell formation. An hypothesis is presented on the basis of published reports of RNA present in the granules and the ultrastructural observations reported here. This hypothesis suggests that the RNA in polar granules is m‐RNA that directs the synthesis of those proteins necessary for the determination of the pole cells to become germ cell

ISSN:0022-104X    

DOI:10.1002/jez.1401670211

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

年代:1968

数据来源: WILEY