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51.
Peter W. Sorensen 《Environmental Biology of Fishes》1986,17(3):185-200
Synopsis Origins of the freshwater attractant(s) of migrating elvers of the American eel were investigated by assaying elvers' responses to rinses of plants, animals, and inanimate objects collected from a Rhode Island (U.S.A.) brook with a sizable elver run. Odor rinses were tested in a Y-maze at naturally occurring concentrations against both blank and brook water. Many items were attractive, several were repulsive, and some caused a reduction in elvers' rheotactic behavior, suggesting that elvers respond to a bouquet of odors. The odor of abundant decaying leaf detritus was highly attractive as were odors of the surfaces of aquatic plants, submerged stones, and migrating alewives. Conspecific odor was only weakly attractive. Because unattractive leaves became attractive when cultured with stream water, microorganisms responsible for detrital decomposition and present in/on most stream objects are thought to be the major source of the attractant(s). Decaying detritus and its associated microorganisms are abundant in most freshwater streams, where they often constitute the ecosystem's primary energy source; their odor could serve as an index of environmental suitability for migrating eels. 相似文献
52.
Physical conditions of propagation media and their influence on the rooting of cuttings 总被引:1,自引:0,他引:1
Hans R. Gislerød 《Plant and Soil》1983,75(1):1-14
Summary The formation and subsequent growth of roots by cuttings of poinsettia, hydrangea, rose and azalea in various propagation media, Jiffy-7, Jiffy-9 and Grodan under different conditions of aeration was investigated. The interrelationships of the effects of air content of the media, temperature and light intensity on the rooting of poinsettia cuttings was also studied.With low air contents (0 cm moisture tension) in the propagation media the formation and growth of roots was strongly inhibited. The rooting performance of rose appeared to be less affected by the poor aeration. Increasing air content improved rooting but best results were obtained at moisture tensions of 4 to 8 cm. Rooting seems to be better correlated with oxygen diffusion rate (ODR) than with air content.For poinsettia cuttings the optimum temperature for rooting was 24 to 28°C. At low temperatures rooting was delayed while at higher temperatures it was almost completely inhibited. Callus formation increased with temperature but decreased with increasing moisture tension. Conditions which induced large callus formation inhibited root formation.High light intensity during rooting reduced overall rooting performance and the inhibition was most pronounced in conjunction with high moisture tensions.Report No. 255. 相似文献
53.
By coupling Anisakis larval hemoglobin with cyanogen bromide-activated Sepharose, a stable and sensitive antigen for the indirect fluorescent antibody test for anisakiasis was prepared. Using this antigen, cross-reaction with other helminth infections was minimized and the test was greatly simplified.Furthermore, the results obtained indicate that this technique may be useful not only in the sero-diagnosis of anisakiasis but may also be applicable to the diagnosis of other helminthic diseases. 相似文献
54.
E. Follenius 《Cell and tissue research》1970,106(1):61-68
Résumé Dans l'hypothalamus de l'Epinoche, certains prolongements nerveux présentent une organisation particulière du réticulum endoplasmique. Des séries de vésicules interconnectées sont disposées en stries transverses espacées de 0,3 à 1,3 . Cette organisation particulière du réticulum endoplasmique existe dans les prolongements nerveux de fort diamètre (1 ), même dans les fibres neurosécrétrices.
Special organization of the endoplasmic reticulum in some hypothalamic nerve processes ofGasterosteus aculeatus
Summary In some nerve processes of the hypothalamus ofGasterosteus aculeatus, the endoplasmic reticulum displays a special organization. Small interconnected smooth vesicles constitute transverse lines spaced between 0.3 and 1.3 . This special organization of the endoplasmic reticulum has been found in nerve processes with a diameter larger than 1 even in neurosecretory ones.相似文献
55.
Bruna Tadolini Diana Fiorentini Laura Landi Luciana Cabrini 《Free radical research》1989,5(4):245-252
To find experimental conditions to selectively study the propagation phase of lipoperoxidation we studied the lipoperoxidation, catalyzed by FeCl2, of liposomes in a buffering condition where Fe2+ autoxidation and oxygen active species generation does not occur. Liposomes from egg yolk phosphatidylcholine. prepared by vortex mixing, do not oxidize Fe2+: on the contrary they oxidize Fe2+ when prepared by ultrasonic irradiation. Dimyristoyl phosphatidylcholine liposomes prepared by ultrasonic irradiation do not oxidize Fe2+. During sonication polyunsaturated fatty acid residues autoxidize and lipid hydroperoxides (LOOH) are generated. Only when LOOH are present in the liposimes Fe2+ oxidizes and its rate of oxidation depends on the amount of LOOH in the assay. The reaction results in the generation of both LOOH and thiobarbituric acid reactive material (TBAR): it is inhibited by butylated hydroxytoluene and has a acidic pH optimum; it is not inhibited by catalase and OH' scavengers. The reaction studied. thus, appears to be the chain branching and propagation phase of lipoperoxidation. When we studied the dependence of Fe2+ oxidation, LOOH and TBAR generation on FeCl2 concentration, we observed that at high FeCl2 concentrations the termination phase of lipoperoxidation was prevalent. Thus. by selecting the appropriate FeCl2 concentration the proposed experimental system allows study of either the propagation or the termination phase of lipoperoxidation. 相似文献
56.
Neville W. Pankhurst 《Environmental Biology of Fishes》1989,26(3):201-211
Synopsis Thirty one species of shallow water teleosts were captured from the NE coast of New Zealand. Ocular morphology was assessed in terms of eye size, pupil shape, theoretical sensitivity and acuity based on retinal morphology, and regional distribution of photoreceptors within the retina. Eye size was relatively or absolutely larger in carnivores than herbivores. Diurnal planktivores and nocturnal species of small body size maximise vision by having relatively large eyes. Anterior aphakic spaces were present in most of the species examined, and 25% of the species also had posterior aphakic spaces. Theoretical sensitivity was generally higher among nocturnal than diurnal species, however, a number of benthic and pelagic carnivores showed retinal specialization for enhanced sensitivity. Diurnal species displayed high spatial acuity, with maximum acuity occurring in carnivorous species. Crepuscular species had either high or low acuity, whereas that of nocturnal species was generally lower than in diurnal species. Ten species displayed regional variation in rod density, with crepuscular and nocturnal species showing streaks of high rod density in the retina. Eleven species of carnivores displayed regional variation in cone density, with highest density usually occurring in the caudal part of the retina. In most of the species with areas of high cone density, there was a forward visual axis that coincided with the location of the aphakic space, suggestive of accomodation along that axis. 相似文献
57.
Synopsis The reproductive biology of the coral reef butterflyfish,Chaetodon multicinctus, was investigated by histological examination of gonads sampled over an 18 month period from a shallow inshore population
on Oahu, Hawaii. Most gonads developed directly from previously undifferentiated tissue. Ovarian development (the structural
formation of lamellae and primary oocytes) was observed in fish ≥44 mm and testicular development (the formation of spermatogenic
crypts) in fish ≥62 mm standard length (SL). In addition, testis formation was identified within the ovarian lamellae of several
differentiated but immature fish. It is hypothesized that prematurational sex change may facilitate monogamy within the highly
competitive social structure of this site attached species. Oocyte development in mature females was marked by distinct phases
of primary growth, the formation of yolk vesicles, and vitellogenesis. Spawning activity was histologically identified by
the maturation and hydration of fully yolked oocytes, and presence of postovulatory follicles. Recently spawned females from
field collections and experimental gonadotropin-treatments exhibited postovulatory follicles that were estimated to persist
at least 24 h after ovulation. Atresia of yolked oocytes was classified into four stages of cell degeneration and resorption.
Monthly analyses of oocyte development and atresia within the sample population show thatC. multicinctus has a protracted annual spawning season with a major peak during the early spring and evidence of spawning activity among
some individuals in the fall. Histological analyses of spawning activity provide more accurate and unambiguous information
than do traditional gonadosomatic assays in this and probably other coral reef fishes. 相似文献
58.
Phillip S. Lobel 《Environmental Biology of Fishes》1989,24(3):161-171
Synopsis The spawning patterns of four Hawaiian reef fishes with similar reproductive habits, but different biogeographic distributions
were studied from September 1980 to October 1981. Two species are Hawaiian endemics [Centropyge potteri (Pomacanthidae) and Chaetodon multicinctus (Chaetodontidae)] and the other two have pan-tropical Pacific distributions [Ctenochaetus strigosus and Zebrasoma flavescens (Acanthuridae)]. All showed increased spawning activity from January to July, the prevalent pattern among a majority of coastal
marine fishes in Hawaii. Environmental correlatives to the period of peak reproduction include cycles of (a) daylight length
and temperature which probably function as proximate cues and (b) seasonal variations in ocean current patterns which may
ultimately affect survival of larvae and dispersal. Peak reproduction takes place during months when (1) mesoscale eddies
most likely occur, and (2) the probability is greatest of drifting objects remaining near the islands. 相似文献
59.
Phillip S. Lobel 《Environmental Biology of Fishes》1989,25(1-3):125-130
Synopsis Spawning by the banded butterflyfish,Chaetodon multicinctus (Chaetodontidae) was observed on coral reefs off Kona, Hawaii. These fish occurred in male-female pairs during normal daytime
activities, a behavior which is typical for the family. Courtship is also a paired male-female activity. During spawning,
however, other individuals (males?) may intrude on the spawning pair. Spawning typically takes place at least a meter or two
above the bottom. The spawning position consists of the male below and behind the female with his snout against the female's
ventral flank or anal fin area. Intruding individuals may join in when the pair is in position and about to spawn. Intruders
line-up against the male in the same position as he is against his female. Underwater photographs are included to illustrate
these behaviors. 相似文献
60.
Valérie Maxime Marguerite Peyraud-Waitzenergger Guy Claireaux Claude Peyraud 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,160(1):31-39
Summary Oxygen consumption, gill ventilation, blood acid-base/ionic status and haemoglobin oxygen affinity were studied in seawater-adapted adult salmon (Salmo salar) during five weeks after transfer into fresh water. Freshwater exposure induced the following changes: Standard oxygen consumption (
) and ventilatory flow (
) decreased markedly during the first days after transfer, then decreased more gradually until a new steady-state was achieved at which
and
were about 80% and 56% of the control values, respectively. The marked increase in oxygen extraction coefficient (Ew
O
2) and the marked decrease in the oxygen convection requirement (
) were associated with a reduction in the partial pressure of carbon dioxide in arterial blood (Pa
CO
2), in spite of a decrease of both ventilatory flow and water CO2 capacitance. These results suggested that transfer into fresh water induced an increase in branchial diffusive conductance. A biphasic pattern was observed in the time-course of the changes in both plasma ion concentration and acid-base status. During the first 10 days, plasma Na+, K+, and Cl– concentrations fell abruptly, then more gradually. [Cl–] decreased more than [Na+] resulting in a progressive increase in the [Na+]/[Cl–] ratio. During the second phase of acclimation to fresh water plasma Na+, K+, and Cl– concentrations progressively increased. [Cl–] increased more than [Na+], so that [Na+]/[Cl–] ratio decreased. Transfer into fresh water did not significantly change plasma lactate concentration. Upon exposure to fresh water, blood pH increased from 7.94±0.04 to 8.43±0.06 at day 10 and then decreased to 8.08±0.03 at day 34. The increase in blood pH induced by transfer to fresh water initially represented a mixed metabolic/respiratory alkalosis. However, after 15 days Pa
CO
2 had returned to pretransfer values and the alkalosis was purely metabolic. The metabolic component of the alkalosis was associated with appropriate changes in the plasma strong ion difference (S.I.D.). Blood alkalosis moved the oxygen dissociation curve to the left, so that P50 was decreased by 30% below the value in seawater for the maximal increase in blood pH. This rise in haemoglobin affinity for O2, associated with a marked increase in blood buffer capacity, are regarded as adaptative processes allowing the salmon to cope with the markedly increased energy expenditure required for upstream migration. 相似文献