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101.
Richard B. Marchase Vincent J. Kidd Angel A. Rivera Michael G. Humphreys-Beher 《Journal of cellular biochemistry》1988,36(4):453-465
Rat parotid gland acinar cells stimulated to divide by a chronic regimen of isoproterenol demonstrate a dramatic increase in the synthesis of the glycosyltransferase 4β-galactosyltransferase. A plasma membrane localization for much of the increase in 4β-galactosyltransferase was determined by density gradient membrane fractionation. Golgi-enriched fractions showed no increase in specific activity, while plasma membrane activity increased 40-fold. This selective increase at the cell surface was confirmed by immunofluorescence of intact, nonpermeabilized cells from treated glands, using a monospecific antibody prepared against the purified bovine milk transferase. In detergent-permeabilized cells staining of nontreated cells was seen only as groups of perinuclear vesicles, presumed to be Golgi apparatus. In isoproterenol-treated and permcabilized cells both presumptive Golgi and cell surface staining was apparent. Enzyme assays performed on intact cells established that the enzyme's active site was oriented to the exterior of the cells. The transferase could be detected as early as 3 hr after the primary challenge with isoproterenol. Pretrcatment of rats with cycloheximide prevented its appearance. 相似文献
102.
Summary Two alternative estimators of individual tree leaf area (A1) area are used to derive estimates of leaf-area index (L) for 40 plots in Pinus contorta Dougl. stands. One estimator of A1 is based on the common assumption of a constant ratio between A1 and sapwood cross-sectional area at breast height (As). The second estimator of A1 accounts for tree-to-tree variation in the relation between A1 and As. The apparent relationship between stand growth and leaf-area index is strongly dependent on the way leaf area is estimated. When L is derived from a constant A1As ratio, stand growth appears to be strongly correlated with L. However, when L is based on estmates of A1 that account for tree-to-tree variation in the A1 — As relation, stand growth is seen to be only weakly related to L. Stand structure, quantified as percent live-crown, accounts for a great deal of the observed variation in leaf-area efficiency. These contrasting relationships illustrate the importance of unbiased estimates of L in interpreting the link between stand-level processes and leaf area.Utah Aggriculural Experiment Station Journal Paper No. 3333 相似文献
103.
Koji Sode Nobuaki Hori Yoichi Mikami Isao Karube 《Biocatalysis and Biotransformation》1988,2(1):51-57
Asymmetric reduction of 2,6,6,-trimethyl-2-cyclohexene-l,4-dione (4-oxoisophrone) to (6R)-2,2,6-trimethyl-1,4-cyclohexane-dione((3R)-dihydro-4-oxoisophorone) was catalysed by immobilized thermophilic bacteria, Thermomonospora curvata JTS 321. Because of leakage of entrapped cells from gel beads during reactions using culture medium, we optimized the medium to allow the microbial conversion under conditions of controlled cell growth. Of the media screened, liver infusion medium was found to be the most suitable and microbial conversion was achieved without cell leakage from the immobilized gels. Immobilized T. curvata cells were repeatedly used for the asymmetric reduction of 4-oxoisophorone, more than 15 times, with an extent of conversion of 50%. 相似文献
104.
L. A. Lacey D. H. Ross C. M. Lacey A. Inman H. T. Dulmage 《Journal of industrial microbiology & biotechnology》1988,3(1):39-47
Summary Four experimental formulations ofBacillus sphaericus Neide (2362 isolate) were evaluated for larvicidal activity against culicine and anopheline larvae in several natural and artificial habitats. A granular formulation (5% primary powder) was tested against natural populations of mosquitoes in two simulated habitats in Florida and in maturing and reflooded rice fields in Louisiana. Larvae ofCulex quinquefasciatus Say were reduced by 97 and 99% after application of the granules at the rate of 10 kg/ha to polluted tanks and 2.5 kg/ha to sod-lined potholes, respectively. Anopheline andPsorophora columbiae (Dyar and Knab) larvae were reduced by 68 and 92–100%, respectively, after application of 5 kg granules/ha to rice fields. A flowable concentrate (12.8% primary powder) applied to unpolluted and organically enriched habitats in Florida at 0.25 kg/ha reduced populations ofCulex spp. by 93–100% and 99%, respectively. Sustained-release briquets (5% primary powder) applied at the rate of one half briquet/1.8 m2 sod-lined potholes reduced larval populations ofCx. quinquefasciatus by 88–95% for up to 2 weeks in open sunlight. Sustained-release pellets (30% primary powder) applied to small woodland pools in Memphis, TN at the rate of four pellets/pool virtually eliminated larval populations ofCx. restuans Theobald for over 8 days. Variable persistance of larvicidal activity was noted for the other treatments depending on the formulation, target species and habitat. 相似文献
105.
Differences in responsiveness to potential prey and pollen were tested in the facultative predator,Euseius tularensis Congdon. Following isolation without food for 16 h, adult female mites were observed with one of the following potential foods: pollen ofMalephora crocea (Jacquin) Schwantes,Scirtothrips citri (Moulton) 2nd instar larvae,Tetranychus pacificus McGregor nymphs and ♂,Panonychus citri (McGregor) nymphs and ♂,E. hibisci (Chant) larvae, andE. tularensis larvae. Responses were compared using the proportion of encounters that resulted in consumption. This proportion was highest when pollen was encountered, followed byS. citri andT. pacificus. Consumption was much lower in response toP. citri and congeneric larvae. WhenS. citri larvae were encountered a 2nd time, 1 to 2 h after the initial capture and consumption, responsiveness increased to a level equal to the response observed with pollen. These results suggest thatE. tularensis is a more effective biological control agent of citrus thrips (S. citri) than of citrus red mite (P. citri). 相似文献
106.
Lise Stengård Hansen 《BioControl》1988,33(1):33-42
The phytoseiid miteAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) was used for biological control ofThrips tabaci Lind. in 7 commercial glasshouses with cucumber (a total of 5780 m2). Predatory mites were introduced 3–4 times in densities ranging from 40 to 300/m2 at each release. In 6 of the 7 glasshouses, control of thrips was satisfactory throughout the growing season. Thrips densities
were kept below 15 individuals per leaf. In 1 glasshouse, thrips damage was seen on the fruits at densities of 25 thrips per
leaf, but the thrips population was quickly reduced and remained at low densities for the next 3 months.
相似文献
107.
M. J. Gormally 《BioControl》1988,33(4):387-395
The effect of 5 constant temperatures (10, 14, 17, 20 and 23°C) on the oviposition and longevity ofIlione albiseta was investigated. Most eggs were laid at 14–17°C and mean oviposition period declined progressively above and below 14°C.
There was no significant difference between oviposition rates or preoviposition periods at each constant temperature, but
the mean number of days between egg laying for each female was significantly greater at 10 °C than at 17, 20 and 23 °C than
at 20 °C. The percentage of infertile eggs laid ranged from 9.2% at 23 °C to 17.9 % at 20 °C and these eggs tended to be laid
at the beginning and end of each oviposition period. A possible association between sex ratio of the emergent adult and temperature
is also discussed.
相似文献
108.
The biology of the noctuid,Tyta luctuosa (Denis & Schiffermüller) (Lep.: Noctuidae), a defoliator of field bindweed,Convolvulus arvensis L., was studied in southern Europe.T. luctuosa is widely distributed and feeds on both thick stands and scattered host populations growing in a diversity of habitats. It
undergoes 2 and perhaps a partial 3rd generation/year in southern Europe and is active during most of the growing season ofC. arvensis. In the laboratory the total time from egg to adult averages 45.6 days. There are 5 larval instars. Adult females deposit
on average over 400 eggs. The larvae being able to feed and develop on native North AmericanCalystegia spp. in the laboratory, there are some reservations about its release in North America. However, the moth has potential value
as a biological control agent for field bindeed in the western USA where it would fill an almost unoccupied niche.
相似文献
109.
J. C. Onillon 《BioControl》1988,33(4):481-494
Les problèmes posés par les ravageurs des Citrus ont pris une importance considérable au cours de ces 3 dernières décennies
et cela pour plusieurs raisons:
Le potentiel de ces ravageurs, pour la plupart plurivoltins, est souvent très important et les conditions climatiques favorables
jointes à la persistance pendant toute l'année de la frondaison assurent des niveaux de populations très élevés. 相似文献
– | - dans un 1er temps, l'on peut invoquer l'introduction accidentelle de ravageurs,Dialeurodes citri Ashm en 1945 (Pussard, 1953),Unaspis yanonensis Kuw. en 1963 (Commeau & Sola, 1964) etAleurothrix floccosus Mask. en 1967 (Onillon, 1969). Ces 3 espèces démunies de leur cortège d'ennemis naturels et trouvant dans leur nouvelle aire de répartition des conditions favorables de développement, ont très rapidement présenté d'importantes pullulations. Ces ravageurs nouveaux sont venus compléter une liste déjà longue d'une dizaine de phytophages majeurs au niveau des plantations d'agrumes du Bassin Méditerranéen; |
– | - un 2ème facteur non négligeable est présenté par un vieillissement des plantations et l'importance du co?t des méthodes culturales d'entretien qui sont comme la taille souvent négligées notamment pour les Citrus d'ornement ou de jardins familiaux. Ces facteurs ont alors pour corollaire le maintien d'arbres à frondaison dense assurant un développement optimum du ravageur; |
– | - enfin le développement d'une lutte chimique d'assurance, génératrice de déséquilibres fauniques particulièrement sensibles au niveau des acariens par élimination d'une partie de l'entomofaune prédatrice ou au niveau des cochenilles telles queAspidiotus nerii Bouché ouParlatoria pergandei Comst. par destruction de l'entomofaune parasitaire utile. |
110.
Gordon A. Fox 《Evolutionary ecology》1992,6(6):482-499
Summary Much of life history theory follows from the idea that natural selection acts on the allocation of resources to competing and independent demographic functions. This paradigm has stimulated much research on the life histories of annual plants. Models of whole-plant resource budgets that use optimal control theory predict periods of 100% vegetative and 100% reproductive growth, sometimes with periods of mixed growth. I show here that this prediction follows from the assumption of independence of the competing vegetative and reproductive compartments. The prediction is qualitatively unchanged even after relaxing important simplifying assumptions used in most models. Although it follows naturally from the assumptions of the models, this kind of allocation pattern is unlikely to occur in many plants, because it requires that (1) leaf and flower buds can never simultaneously be carbon sinks; and (2) organs that accompany flowers, such as internodes and bracts, can never be net sources of photosynthate. Thus while resources are doubtless important for annual plants, an exclusively resource-based perspective may be inadequate to understand the evolution of their life histories. Progress in research may require models that incorporate, or are at least phenomenologically consistent with, the basic developmental reles of angiosperms. 相似文献