摘要:

AbstractThe pericardial sac containing the heart was removed from large (2.7–6.3 kg) longfinned eels (Anguilla dieffenbachii).Coronary arteries were cannulated in preparation for perfusion with eel Ringer or red cell suspensions. The hearts were maintained by Ringer perfusion while the performance of the heart was assessed. Responses of the hearts to increases in filling pressure and output pressure were recorded. Maximum cardiac output was 22.3 ± 1.4 ml/min/kg body mass (mean ± 1 SEM; N = 9). The highest cardiac power output was measured at maximum cardiac output and was 3.39 ± 0.32 mW/g ventricle mass (mean ± 1 SEM; N = 9). Eel hearts could sustain output pressures near 80 cm H2O, but cardiac output was reduced and cardiac power output was 1.89 ± 0.24 mW/g ventricular mass (mean ± 1 SEM; N = 9). Maximum cardiac output decreased by 14% when hearts pumped hypoxic Ringer with a PO2of 11.5 torr. At high input pressures concomitant with high output pressures (80 cm H2O), cardiac power output decreased by 38% upon exposure to hypoxic Ringer. Coronary perfusion of hypoxic hearts with red cell suspensions (mean hematocrit 10.4%) at a rate of 2% of control cardiac output (0.20 ml/min/kg body mass) had no effect on maximum cardiac output. However, coronary perfusion enabled hypoxic hearts to maintain cardiac output when output pressure was raised to 80 cm H2O. Under conditions of high input pressure and high output pressure, power output increased by 20% compared to hypoxic hearts without coronary perfusion. The role of the coronary supply to eel myocardium is discussed in the light of the differences in power output responses of the coronary perfused hypoxic heart to challenges with high filling pressures compared to high‐output pressure challenges. © 1992 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402620202

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe regulatory effects of allelic substitution at thetrans‐actingmapPlocus and of dietary glucose on the expression of the duplicate genes for alpha‐amylase (Amy) inDrosophila melanogasterwere examined in the anterior midgut and posterior midgut regions of mature flies. The levels of amylase activity and amylase protein, as well as the abundance of amylase‐specific RNA, were quantified. All 3 parameters ofAmyexpression were concordant. Results indicate that the effects of bothmapPand dietary glucose are exerted at the level of amylase RNA. However, the tissue‐specific effects ofmapPare restricted to the posterior midgut and can therefore be distinguished from the effects of glucose in food medium, which influences amylase RNA levels in both the anterior and posterior midgut regions. Our data suggest that, in large part, strain‐specific effects of dietary glucose can be explained on the basis of alternate alleles at themapPlocus in different homozygous strains of flies.Levels of amylase RNA in tissue extracts of flies from an amylase‐null strain were also measured. Low levels were observed in both anterior and posterior midgut extracts. These were unresponsive to dietary conditions. © 1992 Wil

ISSN:0022-104X    

DOI:10.1002/jez.1402620203

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

年代:1992

数据来源: WILEY

摘要:

AbstractDevelopment of head neck motion patterns is studied in drinking chickens to examine (1) general motion principles, (2) ontogenetic changes in these patterns, and (3) whether pattern changes are due to scaling effects during growth. Behavioral patterns are analyzed by high speed filming, radiography, and calculation of rotation patterns for each joint during all movement patterns.Flexibility and variability are great, but representative kinematic patterns are selected for immersion, upstroke, and tip‐up phases. Five principles were found that control cervical motion. Two principles maximize rotation efficiency: the geometric and lever arm principles. Two trajectory compensating principles occur; one controls compensation for overflexion, and the other corrects curved into straight trajectories of head motion. One principle occurs that minimizes rotation force if large forces tend to develop in one joint. This principle results in a characteristic cervical motion pattern (“bike chain” pattern).There are three developmental periods: (1) hatchlings (2) chickens 1 to 4 weeks old (1–4W), and (3) older than 4 weeks. Each period is characterized by different kinematic patterns. In 1–4W chicks, the rotation force is minimized. In older stages, the cervical joints rotate according to geometric and lever arm principles. The totally different motion pattern in hatchlings results from a different behavioral reaction to water and the influence of large centrifugal forces. Transitions in cervical motion patterns are connected to effects of scaling, primarily changes in head and body weights. Changes in motion patterns are not related to changes in anatomical characters such as flexion extremes and relative length of each vertebra since these are similar in all stages. © 1992 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402620204

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

年代:1992

数据来源: WILEY

摘要:

AbstractDuring cytokinesis, a cortical contractile ring forms around a cell, constricts to a stable tight neck and terminates in separation of the daughter cells. At first cleavage,Ilyanassa obsoletaembryos form two contractile rings simultaneously. The cleavage furrow (CF), in the animal hemisphere between the spindle poles, constricts to a stable tight neck and separates the daughter cells. The third polar lobe constriction (PLC‐3), in the vegetal hemisphere below the spindle, constricts to a transient tight neck, but then relaxes, allowing the polar lobe cytoplasm to merge with one daughter cell. Eggs exposed to taxol, a drug that stabilizes microtubules, before the CF or the PLC‐3 develop, fail to form CFs, but form stabilized tight PLCs. Eggs exposed to taxol at the time of PLC‐3 formation develop varied numbers of constriction rings in their animal hemispheres and one PLC in their vegetal hemisphere, none of which relax. Eggs exposed to taxol after PLC‐3 initiation form stabilized tight CFs and PLCs. At maximum constriction, control embryos display immuno‐localization of nonextractable α‐tubulin in their CFs, but not in their PLCs, and reveal, via electron microscopy, many microtubules extending through their CFs, but not through their PLCs. Embryos which form stabilized tightly constricted CFs and PLCs in the presence of taxol display immuno‐localization of nonextractable α‐tubulin in both constrictions and show many polymerized microtubules extending through both CFs and PLCs. These results suggest that the extension of microtubules through a tight contractile ring may be important for stabilizing that constriction and facilitating subsequent cytokinesis. © 19

ISSN:0022-104X    

DOI:10.1002/jez.1402620205

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe direct hormonal control of sulfate uptake by cartilage matrix of coho salmon was examined by exposing branchial cartilage to 1 μCi · ml−135SO4for 48 hours at 15°C in a defined medium. Sulfate uptake occurred primarily in cartilage (rather than bone) and the amount of specific uptake was similar in epibranchial and ceratobranchial cartilages. Intact and hypophysectomized coho salmon starved for 22 days had equivalent in vitro sulfate uptake, which in both cases were 30% of the uptake seen in branchial cartilage of fed, intact controls. In branchial cartilage from starved coho salmon, in vitro exposure to recombinant bovine insulin‐like growth factor I (rbIGF‐I) at 1, 10, 100, and 1,000 ng · ml−1caused a dose‐dependent increase in sulfate uptake, with a maximum 3‐fold increase over control at 1,000 ng · ml−1rbIGF‐I. Coho salmon insulin (1, 10, 100, and 1,000 ng · ml−1) resulted in a maximum 30% increase in sulfate uptake at the highest dose. Growth hormone and triiodo‐L‐thyronine had no direct effect on in vitro sulfate uptake. The results indicate that IGF‐I has direct effects on coho salmon cartilage and may be an important regulator of growth in salmon and other tel

ISSN:0022-104X    

DOI:10.1002/jez.1402620206

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

年代:1992

数据来源: WILEY

摘要:

AbstractUsing indirect immunofluorescence methods, we have localized for the first time in the newt,Notophthalmus viridescens, β‐endorphin (β‐ep)‐like immunoreactivity in the neurons of spinal ganglia (SPG), spinal cord (SPC), as well as in the hypothalamic region of the brain. An examination of serially sectioned SPG showed that the β‐ep‐positive neurons, cell bodies, and nerve fibers were distributed at all levels of SPG. Peripheral regions of the perikarya of β‐ep‐positive SPG neurons exhibited intense staining for β‐ep, the central nuclear region remaining nonreactive. In SPC, brightly staining fibers were seen entering the afferent nociceptive input areas, namely the Lissauer's tracts, substantia gelatinosa, and the dorsal ascending columns. Dot‐fiber immunofluorescence pattern was observed throughout the gray matter of SPC representing β‐ep‐positive, secondary sensory neurons as well as interneurons. Also, discrete cluster of neurons located deep in the gray matter of SPC stained positively to β‐epantisera. This study not only demonstrates for the first time the presence of β‐eplike material in the newt, more specifically in SPG and SPC, but also raises the question of a possible link between β‐epand newt limb regeneration as previous work has shown that SPG support limb regeneration in a denervated‐amputated

ISSN:0022-104X    

DOI:10.1002/jez.1402620207

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

年代:1992

数据来源: WILEY

摘要:

AbstractTo better characterize the cells involved in newt limb regeneration, blastemal cells from accumulation and differentiation phase blastemas were grown in dissociated cell culture, and their morphology and antigenic phenotype determined using a variety of antibodies directed against intermediate filaments, cell adhesion molecules, and extracellular matrix molecules. In addition to previously described blastemal cell morphologies, many of the cells in these cultures had a round cell body, with an eccentrically placed nucleus and a cytoplasm filled with autofluorescent granules. The majority of accumulation phase blastemal cells labeled with antibodies against GFAP, vimentin, 22/18 as well as with antibodies against NCAM, L‐1, laminin, and fibronectin. The majority of differentiation phase blastemal cells had a similar phenotype but lacked expression of vimentin and fibronectin.Comparison of the blastemal phenotype in vitro and in vivo showed similar expression characteristics. However, in differentiation phase blastemas, laminin immunoreactivity was concentrated in specific locations. In addition, the proliferation of cultured blastemal cells is stimulated by the addition of a crude brain extract, consistent with previous studies in vivo and in vitro. Taken together, these observations suggest that dissociated cultures of newt limb blastemal cells provide a suitable model for the analysis of the cell and molecular mechanisms involved in limb regeneration. © 1992 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402620208

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

年代:1992

数据来源: WILEY

摘要:

AbstractNasal one‐third sized fragments were created from fully differentiated larvalXenopuseyes (stage 47). At various times post‐surgery, animals were injected with tritiated thymidine. All animals were fixed 1 day post‐injection. Animals injected 1 day post‐surgery showed limited healing and thymidine labeling in the retina. In animals injected 1 week post‐surgery, heavy thymidine label was localized in the ventrotemporal retina in a “thickened” neuroepithelium internal to the extending pigmented retinal epithelium. In contrast, the dorsal retina showed no apparent extra labeling, but rather resembled normal ciliary margin. In animals injected 1 month post‐surgery, the eye fragment regained normal size and retinal layering, and the label was restricted to the ciliary margin. Regenerative growth associated with healing appeared to have been completed by this time.This extra cell division that occurs during the 1st month post‐surgery may underlie novel axonal targeting properties shown by nasal one‐third sized fragments. For example, these findings are consistent with the idea that pattern duplication of the visuotectal projection in nasal one‐third sized eye fragments occurs via intercalary cell division during healing and regeneration.

ISSN:0022-104X    

DOI:10.1002/jez.1402620209

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

年代:1992

数据来源: WILEY

摘要:

AbstractHemocytes from the solitary urochordateStyela clavacan effect allogeneic cytotoxicity in vitro. Spectrophotometric and microscopic quantification of eosin‐y dye exclusion revealed significantly greater frequencies of cell death in allogeneic hemocyte cultures when compared to autogeneic controls. This cytotoxic response was characterized by 1) transient activity such that specific cytotoxicity could be detected for only 4 hours of culture though continued specific killing may have been obscured by spontaneous cell death; 2) a necessity for cellular interaction demonstrated by the elimination of allogeneic cytotoxicity in the absence of cell contact; 3) killing of multiple targets by effector cells due to high levels of response at low allogeneic ratios; 4) insensitivity to altered temperature; 5) increased cytotoxicity in the absence of autologous plasma; 6) an absence of xenogeneic reactivity; 7) the presence of three hierarchical levels (low, intermediate, and high) of response. These data reflect events involved in the recognition of allogeneic cellular determinants resulting in specific cytotoxicity effected by immunocompetent cells. Such in vitro recognition and cytotoxic recognition and cytotoxic reactivity may be responsible for adaptive reactions caused by histoincompatibility in solitary tunicates. © 1992 Wiley‐Liss,

ISSN:0022-104X    

DOI:10.1002/jez.1402620210

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

年代:1992

数据来源: WILEY

摘要:

AbstractThree monoclonal antibodies (MAbs) were produced against materials obtained from the golden hamster oviduct. The MAbs (C11E8, C8B11, and A3D5) selectively reacted with the zona pellucida (ZP) of oviductal eggs. An immunohistochemical study demonstrated that all MAbs bound strongly to the epithelial cells of the oviduct and, to a lesser extent, of the uterus, the cervix, and the vagina. Weak reactions were also observed with some other tissues. All immunohistochemical reactions were completely eliminated by treatment of tissues with periodic acid, suggesting that the antigenic determinants that react with the MAbs are carbohydrate in nature. Antigens that reacted with the MAbs were characterized by immunoblotting analyses of 1‐ or 2‐dimensional polyacrylamide gels after electrophoresis to fractionate tissue extracts under reducing conditions. With the oviductal extract, C11E8 and A3D5 specifically bound to broad bands that corresponded to macromolecules of more than 200 and 160 kD, respectively, whereas C8B11 reacted with a broad range of macromolecules, with the strongest reactivity being detected at molecular weights (MWs) higher than 160 kD. The macromolecules that reacted with the MAbs had carbamilation trains, suggestive of extensive microheterogeneity with respect to charge and size. Similar substances of high MW were not detected in extracts of tissues from the other reproductive organs. In addition, one MAb‐positive oviductal antigen bound to the ZP of ovarian eggs, but the others did not bind to the ZP of ovarian eggs. This result indicates that the binding activity is specific for the oviductal glycoproteins. We have thus established clones that produce 3 different MAbs with strong affinity for oviduct‐specific glycoproteins, one of which is associated with the ZP of the golden hamster. © 1992 Wiley

ISSN:0022-104X    

DOI:10.1002/jez.1402620211

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

年代:1992

数据来源: WILEY