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151.
152.
John M. Robinson Sylvia A. Larrimore David W. Craft H.E. Heath Gary L. Sloan 《Biochemical and biophysical research communications》1982,109(3):730-737
The extracellular protease, endopeptidase, and hexosaminidase produced by were neither induced nor repressed by amino acids but required a tryptic digest of casein for their production. Catabolite repression of exoenzyme production by glucose was not affected by exogenous cyclic adenosine 3′, 5′-monophosphate but was partially relieved by di- or monobutyryl derivatives of this compound. 相似文献
153.
154.
A bioassay was developed by Rittschof el al. (1983) to examinedistance chemoreception in the predatory marine gastropod, Urosalpinxcinerea. This bioassay was used to test the effect of a senesof low mol. wt. organics on the ability of newly hatched oysterdrills to detect a prey odor released from barnacles, Balanusbalanoides. Two series of low mol. wt. organics were testedusing methanol as the reference compound. In one series, R-OH,the carbon chain length was varied from 1 to 4. In the secondseries, CH3-R, the chain length was held constant while thefunctional group, R, was varied. When these compounds were presentin the rnM range, they inhibited the creeping response of oysterdrills towards barnacle prey odor. In the CH3-R series, inhibitionincreased in the following order: sodium acetate > ethylacetate > acetonitnle > methanol; and, in the alcoholseries C1 to C4, inhibition increased with increasing chainlength. No creeping response was observed when these compoundswere tested in the absence of prey odor. 相似文献
155.
The Orlando Easterly Wetland (OEW), located near Christmas, Florida, USA, is among the longer-lived treatment wetlands in the United States. It was established in the late 1980s to reduce nitrogen and phosphorus concentrations from tertiary treated wastewater bound for the St. Johns River. A goal of 0.07 mg/l total phosphorus concentration has been set by the regulating agency (St. Johns River Water Management District). In order to understand and define the operating conditions for which this target could be met, a systematic study of historic phosphorus uptake was performed using a traditional first-order model. Phosphorus uptake performance is shown to correlate well with hydraulic performance for two parallel upstream cells. The first-order model is enhanced with predictive capabilities that acknowledge the correlation between the phosphorus uptake rate constant and the hydraulic loading rate observed in the system. Inherent limitations with the first-order modeling approach are addressed and uncertainty in model performance is used to bound predictions. 相似文献
156.
William P. Jacobs 《American journal of botany》1976,63(5):571-577
The movement and polarity of zeatin, a highly active, endogenous cytokinin, through petioles and roots were tested in the classical experimental arrangement using excised 5-mm sections. Zeatin in the receiver cylinders of agar was measured by soybean callus bioassay and by liquid scintillation counting of 14C that had been added in the donor cylinders as [8-14C] zeatin. Both methods agreed in showing movement, but there was no polarity in Coleus #5 petioles. The amounts moved were about one-tenth of the GA-3 movement through petioles of the third pair of leaves of the same clone. Movement of 14C-zeatin through Pisum roots was similarly statistically significant but non-polar; the amounts moved were similar to those previously observed for polar GA-3 movement through Zea roots. 相似文献
157.
William Russell 《BMJ (Clinical research ed.)》1984,288(6416):580
158.
159.
High hydrostatic pressure applied between sperm attachment and the onset of cortical granule exocytosis will inhibit this exocytotic event in sea urchin eggs. Such pressure-treated zygotes, nevertheless, are activated and capable of development. Thus, this technique can be used as a tool to study the relationship between cortical granule breakdown and other fertilization-related responses. We have studied whether the exocytosis of cortical granules is necessary for proton efflux (acid release) to occur. Our results indicate that although Ca2+ is released while the eggs are under pressure (a prerequisite for the following events to take place), cortical granule exocytosis and acid release are pressure-sensitive and completely inhibited at pressures above 400 atm (6000 psi) and 275 atm (4000 psi), respectively. However, upon decompression, acid release is initiated which amounts to 65–70% of that seen in the unpressurized controls, suggesting that the efflux mechanism does not require cortical granule exocytosis and must result from some modification of the original plasma membrane of the egg. The remaining 30–35% of the acid release is related to cortical granule exocytosis, since it can be obtained upon induction of the cortical granule fusion 30 min later under atmospheric pressure. The initiation of acid release after decompression indicates that the efflux mechanism is not transiently turned on at fertilization, but undergoing long-term modification; the recovery of the ability to induce cortical granule fusion after fertilization under pressure suggests a refilling of cytoplasmic Ca2+ stores within this time course. 相似文献
160.
William A. Rottschaefer 《Theorie in den Biowissenschaften》2002,121(2):175-203
Summary Proponents of Developmental Systems Theory (DST) argue that it offers an alternative to current research programs in biology
that are built on the historic disjunction between evolutionary and developmental biology. In this paper I illustrate how
DST can be used to account for the acquisition of an important component of moral agency, conscience. Susan Oyama, a major
proponent of DST, has set moral issues outside the compass of DST. Thus, I examine her reasons for restricting DST to non-moral
matters, and argue that they are not decisive. On the positive side, I argue that DST not only is compatible with attempts
to describe and explain moral agency but also aids us in understanding it. In particular, I show how DST can provide a fruitful
perspective for viewing some significant current findings and theories in moral developmental psychology about the acquisition
of conscience. The familiar dichotomies resisted by DST, those between genes and environment, inherited and acquired, innate
and learned, and biological and cultural, have also plagued human developmental psychology, including moral development. By
bringing a DST perspective to the study of moral development, I illustrate how a DST perspective might offer a promising way
to reconceive that phenomenon, and provide some insights into how further work in understanding the development of moral agency
might proceed. Thus, I hope to contribute to the current efforts of proponents of DST to integrate developmental and evolutionary
considerations. 相似文献