摘要:

AbstractThe reaction of a group of 40 worker honeybees to exposure to the major compound of the alarm pheromone Iso‐pentyl‐acetate (IPa) can be easily quantified by their metabolic response. A flow through system oxygen consumption of the bees shows a characteristic increase within 30 sec after the application of IPA. There are significant differences in response among colonies in the tested population; these were most extreme for 4‐day‐old workers. As there is a highly significant correlation between the colony defense in the field and the metabolic laboratory test, this technique may be usable as a routine in breeding programs for honeybees with low defensive b

ISSN:0022-104X    

DOI:10.1002/jez.1402350102

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

年代:1985

数据来源: WILEY

摘要:

AbstractHeart output, arterial pressures, and heart rate were measured directly in conscious unrestrained eels (Anguilla australis) and responses to intra‐arterial injection of adrenaline monitored. Adrenaline increased systemic vascular resistance, heart output, and cardiac stroke volume in all animals. In some cases small transient decreases in stroke volume and hence heart output were seen at the peak of the pressor response: These probably reflect a passive decrease in systolic emptying due to increased afterload on the heart. In most cases, adrenaline produced tachycardia; but two animals showed consistent and profound reflex bradycardia, which was accompanied by a concomitant increase in stroke volume such that heart output was maintained or increased slightly. The interaction of changes in heart output and systemic vascular resistance produced complex and variable changes in arterial pressure. There was no consistent pattern of changes in branchial vascular resistance. Atropine treatmentin vivorevealed vagal cardio‐inhibitory tone in some animals and always blocked the reflex bradycardia seen during adrenaline induced hypertension. In some animals, adrenaline injection after atropine pretreatment led to the establishment of cyclic changes in arterial pressure with a period of about 1 min (Mayer wav

ISSN:0022-104X    

DOI:10.1002/jez.1402350103

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe electrophoretic patterns of hemoglobin (Hb) and the functional properties of blood of seven migratory fish species, in two different kinds of habitat during both the rainy and dry seasons, were studied. All species showed multiple hemoglobins and very similar electrophoretic patterns except forSchizodon nasutus, which showed two cathodal components. The functional properties of blood reflect those electrophoretic patterns, since all species showed very little or no Bohr effect during each situation studied. Data onLeporinus obtusidensblood (during the rainy season), from both lotic and lentic environments, showed a normal Bohr effect (ϕ = −0.073). Similarly,Schizodon nasutusandLeporinus fridericifrom a lotic environment during the dry season were compared and showed a reverse Bohr effect (ϕ=0.042). In the other 14 situations, onlyLeporinus elongatusfrom a lentic environment during the rainy season showed a statistically significant difference in log P50values from the other fis

ISSN:0022-104X    

DOI:10.1002/jez.1402350104

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe inner ear of anuran amphibians appears to be exceptionally sensitive to substrate vibration. The opercularis system, consisting of an opercularis muscle running from the shoulder girdle to a movable, cartilaginous operculum lying next to the inner ear, has been hypothesized to be involved in driving these seismic responses. Removal of the opercularis muscle of adult bullfrogs,Rana catesbeiana, caused clear decreases in microphonic responses of the inner ear to vibrations from 20–250 Hz and 0.05–5.0 cm/sec2accelerations. Degree of decrease in responsiveness was variable between individuals and between different frequencies of stimulation, ranging up to 90% reduction at certain frequencies and in certain specimens. Decreases were most marked at lower frequencies below about 50 Hz. Additional removal of the levator scapulae superior muscle, which runs alongside the opercularis muscle from the shoulder girdle to ventrolateral portions of the otic capsule, also tended to depress responses, although this effect was substantially less (generally less than 10%) and also less consistent. As the opercularis muscle appears to be derived from the levator scapulae musculature, it is speculated that primitively seismic sensitivity was enhanced by a muscular connection that could transmit motion from the forelimb to the otic region, responsiveness being further enhanced by the subsequent evolution of the specialized opercularis sys

ISSN:0022-104X    

DOI:10.1002/jez.1402350105

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

年代:1985

数据来源: WILEY

摘要:

AbstractMorphological and electrophysiological correlates of giant nerve fiber development were examined during posterior segmental regeneration in the earthworm,Eisenia foetida. Seven days after amputation of the last 40 segments a small undifferentiated tail bud was evident. Tactile stimulation of this bud evoked all‐or‐none lateral giant fiber (LGF) spikes in original (substrate) segments adjacent to the bud, suggesting an early expansion of the LGF sensory field into the bud. This idea was further supported by experiments involving selective cutting of (and electrical recording from) ventral nerve cord and segmental nerves in the substrate segment immediately adjacent to the bud. By 12–16 days after amputation, segmental delineation of the bud was completed, lateral and medial giant fibers were evident in cross sections of the bud, and all‐or‐none giant fiber spikes were detected in surface recordings from the bud. LGF spikes, evoked by touching any of the bud segments, were readily conducted (velocity ≅ 1.0 m/s) along the bud and into substrate segments. During the next few weeks, giant fiber conduction velocities increased gradually in the bud and eventually were comparable to those in normal posterior segments. The patterns of conduction velocity increases during posterior segmental regeneration closely paralleled those of normal post‐embryonic development in poste

ISSN:0022-104X    

DOI:10.1002/jez.1402350106

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

年代:1985

数据来源: WILEY

摘要:

AbstractRegeneration was examined in fissioned and unfissioned planarians (Dugesia tigrina) in terms of regenerative success and body proportioning. Regenerative success was determined in terms of percent of abnormal regenerates and number of abnormalities per abnormal regenerate. Sections from unfissioned animals were less successful at regeneration than were those from fissioned animals, and body regions located immediately behind the pharynx represented those segments which formed fewer abnormal regenerates as a result of fissioning. Body proportioning was measured as a function of size of head and prepharygeal region to overall body length. A direct correlation was seen in the proportional size of these two parameters, which varied significantly among regenerates. Results suggest that body proportioning is not constant from one excised piece to another but is predictable and dependent on several variables including interval between fission and sectioning, region from which the segment was obtained, and/or original length of the segment.

ISSN:0022-104X    

DOI:10.1002/jez.1402350107

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

年代:1985

数据来源: WILEY

摘要:

AbstractMelanophores of the medakaOryzias latipesrespond to the stimulation of alpha adrenergic receptors with a rapid centripetal translocation (aggregation) of melanosomes. Preincubation of isolated melanophores in hexylene glycol with or without colchicine results in an inhibition of melano‐some aggregation concomitantly with the disarrangement of the cytoplasmic microtubular framework. Incubation in hexylene glycol at higher concentrations induces structural modification and disassembly of preexisting microtubules, especially in the perinuclear region of the cells. A microtubule inhibitor, nocodazole, also inhibits melanosome aggregation through disruption of micro‐tubules. These results indicate that both the presence of a substantial number of microtubules and their innate arrangement are indispensable for the rapid centripetal translocation of melanosomes. The results also suggest that micro‐tubules undergo cycles of disassembly and reassembly during pigment mov

ISSN:0022-104X    

DOI:10.1002/jez.1402350108

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe in vivo incorporation of3H‐uridine into RNA was studied in delayed implanting and activated blastocysts obtained from 33 western spotted skunks.3H‐uridine was incorporated into RNA by all blastocysts; however, significantly more label was incorporated as blastocyst diameter increased. Activated blastocysts with diameters of 1.6 mm or greater on average incorporated 65 times more3H‐precursor in 5 hr than diapausing blastocysts with diameters of 1.1 mm or less. Polyadenylated RNA was likewise synthesized by delayed implanting and activated skunk blastocysts; however, the proportion of polyadenylated RNA synthesized by the former was greater than in the latter (43.9% vs. 27.5%). Our data suggest that the transition from embryonic diapause to fully activated blastocysts first occurs gradually for several days before entering a 1–2‐day period of rapid development characterized by an abrupt increase in RNA acc

ISSN:0022-104X    

DOI:10.1002/jez.1402350109

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe absence of DNA in the yolk platelets ofBufo arenarumoocytes was verified. Oocytes from the coelomic cavity were used in order to avoid possible contamination by the ovarian tissue. Four methods for DNA analysis were employed, and the possibility of interference was carefully checked. The presence of three possible contaminants, which produced positive reactions from the DNA analysis, was detected. These were the glycosaminoglycan from the superficial layer of the platelets, sucrose, and polyvinylpyrrolidone from the buffer commonly used during the isolation of platelets.The present evidence points to the necessity of using at least two different methods for DNA determination with due regard for their sensitivity and specificity before any firm conclusion can be reached on the presence or absence of DNA in nonnuclear and mitochondrial parts of the oocyte.

ISSN:0022-104X    

DOI:10.1002/jez.1402350110

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe in vitro effects of pH on goldfish (Carassius auratus) ovulation were investigated. Final oocyte maturation and follicular detachment were induced in vivo in gravid goldfish by HCG injections and elevated holding temperatures. Females were biopsied to determine the time of germinal vesicle breakdown and when oocytes should be removed for in vitro incubations. Prior to ovulation, the ovaries were removed, dissected and mature intrafollicular oocytes were incubated in media of varying pH (7.3–8.9). There was a significant increase in ovulation as the pH of the incubation increased and this ovulation could be blocked by indomethacin. Indomethacin did not inhibit the actual mechanism of oocyte expulsion since exogenous PGF2αinduced ovulation in indomethacin blocked incubates. Increased pH did not increase the ovulatory response observed with exogenous PGF2α. The combined results suggest that an increase in incubation pH stimulates prostaglandin synthesis that, in turn, stimulates ovulat

ISSN:0022-104X    

DOI:10.1002/jez.1402350111

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

年代:1985

数据来源: WILEY