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101.
A. M. J. P. Kuijpers H. A. M. Ketelaars L. W. C. A. Van Breemen 《Aquatic Ecology》1992,26(2-4):379-383
For three years chironomid larvae were collected bimonthly with a grab sampler in two deep storage reservoirs in The Netherlands. Chironomid pupal exuviae were collected monthly, from April to November, with a handnet. Net samples yielded more taxa than grab samples. The taxa found in net samples originated from more habitats, than taxa found in grab samples. The relative contribution of Orthocladiinae was much larger in net samples. Based on the results obtained in the two reservoirs, some advantages and disadvantages of both sampling methods are discussed. 相似文献
102.
Annual growth rate of the calcareous red alga Lithothamnion corallioides (Corallinales,Rhodophyta) in the Bay of Brest,France 总被引:1,自引:0,他引:1
Lithothamnion corallioides Crouan et Crouan (Rhodophyta, Corallinales) is the main constituent of the maerl beds of the Bay of Brest (Atlantic coast of western Brittany). Its growth rate was measured monthly in situ during one year. Growth rates were obtained by an adaptation of the buoyant weight technique. The highest daily growth rate was observed in July and reached 0.26 % d–1 (S.D. = 0.06), when expressed as the increase of calcium carbonate weight. The average daily growth rate was 0.12% d–1 (S.D. = 0.04) for a period of 275 days (summer and autumn 1988, winter 1989). Using this preliminary data, the calcium carbonate accretion rate can be estimated provisionally: 876 g m–2 year–1, a rate much lower than that of tropical reef coralline algae, but higher than that of Lithophyllum incrustans, the well known temperate European reef-builder. 相似文献
103.
Rats were exposed intermittently for 8h per day over 6 days at simulated high altitude of 20 000 feet. One group of altitude-exposed animals was treated with naproxen, a prostaglandin inhibiting drug. Significant reduction in body weight gain was observed in both altitude-exposed and drug-treated altitude-exposed animals compared to the control group. Right and left ventricular weights and weights of the adrenal glands were increased significantly in altitude-exposed and altitude-exposed drug-treated animals. The weight of the spleen was increased significantly in altitude-exposed animals whereas no such increase of splenic weight was observed in drug-treated altitude-exposed group of animals. On the other hand, the weight of the liver was decreased significantly in both cases. In drug-treated altitude-exposed animals, the unaltered splenic weight was thought to be due to inhibition of the erythropoietic activity. 相似文献
104.
J. P. R. Ochieng'-Odero 《Entomologia Experimentalis et Applicata》1990,54(1):21-27
Adult reproductive performance is linked to the period of feeding done by the final instar larva after attainment of a larval critical weight (LCW). The highest weight attained by a final instar larva is referred to as the larval maximum weight (LMW) and is the onset of the pre-pupal period. The relationships between LCW, pupal weight (PW) and adult weight (AW) are described as functions of the LMW. In the leafroller Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) LCW was dependent on larval size and was approximately 75% of the mean LMW. LCW was about 29 mg and 36 mg for male and female larvae of 1.18 mm and 1.20 mm head-capsule width, respectively. Over three successive generations of laboratory rearing, PW was approximately 30% and 25% lower than the LMW for males and females, respectively. AW was consistently about 50% and 40% lower than the PW for males and females, respectively. The decrease in weight from LMW to PW was named as the constant DP and found to be 0.3 for males and 0.25 for females. The total decrease from LMW to AW was the constant DA and was 0.6 for males and 0.5 for females. The duration of the latent feeding period was positively correlated to PW and AW. LCW may be used to derive quality indices that describe and predict pupal and adult performance.
Résumé Les performances reproductives sont liées à la période d'alimentation du dernier stade larvaire après l'obtention d'un poids critique (LCW). Le poids maximal atteint au dernier stade larvaire est défini comme le poids larvaire maximal (LMW), il correspond au début de la période prénymphale. Les relations entre poids de la chrysalide (PW) et poids de l'audulte AW) sont présentées comme des fonctions de LMW). Chez Cnephasia jactatana Walker (Lep. Tortricidae), LCW dépend de la taille de la chenille et correspond à environ 75% de la valeur moyenne de LMW. LCW est respectivement de 29 mg et 36 mg pour les chenilles mâles et femelles dont les capsules céphaliques ont 1,18 et 1,20 mm. Pour 3 générations successives, PW est environ 30% et 25% inférieur à LMW des mâles et des femelles. La régression du poids de LMW à PW est désignée comme la constante DP et vaut 0,3 pour les mâles et 0,25 pour les femelles. La régression de LMW à AW est désignée comme la régression DM et vaut 0,6 pour les mâles et 0,5 pour les femelles. La durée de la période d'alimentation latente est liée positivement à PW et AW. LCW peut être utilisé comme indice dérivé décrivant et prédisant les potentialités nymphales et imaginales.相似文献
105.
Roderick T. Bronson 《American journal of physical anthropology》1981,56(1):77-81
Necropsy data from a Primate Center were used in a study of the brain weight-body weight relationships of 12 species of nonhuman primates. The sample sizes ranged from six Cercopithecus aethiops to 163 Macaca mulatta. By plotting mean brain-mean body weight of each species on log-log paper, it was shown that the straight line fitting the plots of all species had a slope of 0.72. Slopes for three species of the genus Macaca, and for six species of the family Cebidae, were 0.61 and 0.81 respectively. Coefficients of determination of the three lines were greater than 0.90. Two species of the family Cebiade, Saimiri sciureus and Aotus trivirgatus, had equivalent body weights, but the former had a 30% larger brain than the latter. The results suggest that brain-body weight scaling characteristics of primate species can be studied effectively using necropsy data. Some statistically significant discrepancies between these and published data, however, show that more data are required to describe these characteristics with greater certainty. 相似文献
106.
J. M. F. Wyatt P. B. Siegel J. A. Cherry 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1982,61(3):257-262
Summary The research presented here was designed to investigate the mode of inheritance of fat and lean tissue deposition, and the relationship between them and body weight in Japanese quail. Heterotic effects were found for weight, size, and number of adipocytes in the abdominal fat depots, weight of the sartorial fat depot and percentage carcass fat with means for the hybrids being lower than those for the parental lines. General inferences concerning the importance of nonadditive genetic variation for lean and body weight were precluded due to inconsistencies observed among mating combinations. Thus, although heterosis and recombination effects were general for characteristics associated with fat deposition, the situation for body weight and lean was unique to the populations involved. It may be hypothesized that heterosis in the efficiency of feed utilization is reflected by the heterosis for fat deposition which explains why hybrids utilize feed better than their parental lines. 相似文献
107.
The Benzodiazepine/GABA Receptor Complex: Molecular Size in Brain Synaptic Membranes and in Solution 总被引:9,自引:7,他引:2
Abstract: The molecular size of the benzodiazepine (BZ) receptor in the synaptic membrane of brain cortex (bovine or rat) was determined by an improved version of the radiation inactivation method to be 220,000. An identical size was found simultaneously for the associated γ-aminobutyric acid (GABA) receptor and for the component binding β-carboline esters. It is proposed that all three activities reside in a single protein or protein complex in the membrane. The size in solution, after extraction into Triton X-100 medium from exhaustively washed membranes, was estimated by sedimentation constant (9.4S) and by gel filtration (∼230,000 apparent MW), again with the BZ and GABA binding activities behaving identically. This size applies to the component that undergoes photoaffinity labelling by [3 H]flunitrazepam in the membrane, and contains a 51,000 Mr polypeptide as the BZ-binding subunit. It is concluded that a protein complex or oligomer of 200,000–220,000 MW carries a class of BZ-binding sites and an associated class of GABAA sites. 相似文献
108.
The rate of oxygen uptake and the amount of several main cell constituents were determined in NPV-infected and uninfected isolated pupal abdomens of the silkworm, Bombyx mori. The oxygen uptake in uninfected isolated abdomens increases for the first 2 days due to the effect of water injection, but thereafter it remains almost unchanged at a relatively low level. When isolated abdomens are infected with an NPV, the oxygen uptake increases markedly from 3 days postinfection onward, being about three times that of uninfected isolated abdomens at late stages of infection. The amounts of cell constituents analyzed in the present study change little in uninfected isolated abdomens throughout the experiment. Infection of NPV leads to a marked accumulation of both DNA and RNA, and a loss of glycogen. The amount of protein, lipid, and sugar are scarcely affected by NPV infection. These results indicate that the activity of metabolism in uninfected isolated abdomens is not only low but also stable, and that infection of NPV results in an activation of host cell metabolism. It is considered that such isolated pupal abdomens provide an excellent opportunity to analyze both the process of NPV replication and the alteration of host cell metabolism resulting from NPV infection. 相似文献
109.
H. Nthel 《Mutation research》1981,84(2):291-304
In earlier work, immature oocytes of the irradiated population RÖI4 of Drosophila melanpgaster were found to be radioresistant relative to those of the basic population RÖI and to those of the control population Berlin wild (+K). The resistance of RÖI4 relative to RÖI was previously attributed to a hypothetical “factor” rar-3. In the present paper, evidence is presented to show that rar-3 is a single, recessive genetic factor, located on chromosome 3 at a map position of about 49.8. The action of rar-3 is apparently independent of that of rar-1 and rar-2, the factors already present in RÖI. 相似文献
110.
Rapid effects of indole-3-acetic acid (IAA) on the mechanical properties of cell wall, and sugar compositions, intrinsic viscosity and molecular weight distribution of cell wall polysaccharides were investigated with excised epicotyl segments of Vigna angularis Ohwi et Ohashi cv. Takara.
- 1 IAA caused cell wall loosening as studied by stress-relaxation analysis within 15 min after the IAA application.
- 2 IAA stimulated the decrease in the content of arabinose and galactose in the hemicellulose 1 h after its application. The amounts of other component sugars in the cell wall polysaccharides remained constant during the IAA-induced segment growth.
- 3 The intrinsic viscocity of the pectin increased as early as 30 min after the IAA application. This effect was not prevented when elongation growth of the segment was osmotically suppressed by 0.15 M mannitol.
- 4 Gel permeation chromatography of the pectin on a Sepharose 4 B column demonstrated that IAA caused increase in the mass-average molecular weight of the pectin. Analysis of the sugar compositions of the pectin eluted from the Sepharose 4 B column indicated that IAA increased the molecular weight of the polysaccharides composed of uronic acid, galactose, rhamnose and arabinose. This effect became apparent within 30 min after the IAA application. Furthermore, IAA increased the molecular weight of the pectin when elongation growth of the epicotyl segments was osmotically suppressed by 0.15 M mannitol.
- 5 Hemicellulose of the cell wall chromatographed on a Sepharose CL-4 B column. Analysis of the neutral sugar compositions and the iodine staining property (specific for xyloglucans) of the polysaccharide solution eluted from the column indicated that the hemicellulose consisted of xyloglucans, arabinogalactans and polysaccharides composed of xylose and/or mannose. IAA caused a decrease in the arabinogalactan content and depolymerization of xyloglucans. These IAA effects became apparent within 30 min after the IAA application. These changes occurred even when elongation growth of the epicotyl segments was osmotically suppressed by 0.15 M mannitol.