Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

phoS is the structural gene for the phosphate-binding protein, which is localized in periplasm and involved in active transport of phosphate in Escherichia coli. It is also a negative regulatory gene for the pho regulon, and the gene expression is inducible by phosphate starvation. The complete nucleotide sequence of the phoS gene was determined by the method of Maxam and Gilbert (A. M. Maxam and W. Gilbert, Methods Enzymol. 65:499-560, 1980). The amino acid sequences at the amino termini of the pre-PhoS and PhoS proteins and at the carboxy terminus of the PhoS protein were determined by using the purified proteins. Furthermore, the amino acid sequence of enzymatically digested peptide fragments of the PhoS protein was determined. The combined data established the nucleotide sequence of the coding region and the amino acid sequence of the pre-PhoS and the PhoS proteins. The pre-PhoS protein contains an extension of peptide composed of 25 amino acid residues at the amino terminus of the PhoS protein, which has the general characteristics of a signal peptide. The mature PhoS protein is composed of 321 amino acid residues, with a calculated molecular weight of 34,422, and lacks the disulfide bond and methionine. The regulatory region of phoS contains a characteristic Shine-Dalgarno sequence at an appropriate position preceding the translational initiation site, as well as three possible Pribnow boxes and one -35 sequence. the nucleotide sequence of the regulatory region of phoS was compared with those of phoA and phoE, the genes constituting the pho regulon.
 ...
PMID:Nucleotide sequence of the phoS gene, the structural gene for the phosphate-binding protein of Escherichia coli. 636 94

In the rotifer Brachionus calyciflorus there occurs a cyclomorphic variation concerning the absence or the presence of a pair of postero-lateral spines. If present, these spines may vary up to lorica length. The production of these spines is induced by starvation, low temperature, or a peptide substance released into the medium by the predacious rotifer Asplanchna. The first two factors apparently induce spines only up to a relative short length, while extremely long spines appear to be induced only by the Asplanchna substance. 1. Existing hypotheses with regard to possible adaptive values of the cyclomorphic spine production are discussed and rejected with the exception of two, which are tested by laboratory experiments. 2. The hypothesis of Erman, that spined Brachionus calyciflorus swim more slowly and filter the nourishment more effectively as a consequence of the resistance of the spines to friction, is disproved experimentally (see Table 1 and 2). 3. The hypothesis of Beauchamp and of Gilbert, that spines form a protection against the predacious Asplanchna, is tested in detail. a) The components of the predator-prey relationship of Asplanchna and the influences of the spines on these components are studied in short term experiments (stopped after the first catch; see Fig. 2 and Table 3): The number of accidental collisions with Asplanchna is not influenced by spine length. However, by increasing spine length the rate of catches per collision and the rate of swallowed prey per catch decrease, and the time spent in swallowing the prey increases. The timespan from the start of the experiment to the moment when the first prey is just being swallowed shows a marked increase with growing spine length (see Table 3: g). b) In experiments of longer periods of exposition (up to one hour; see Table 5) the long-spined B. calyciflorus are again nearly completely unassailable. In these cases the advantage of short-spined animals (compared with spineless ones) is reduced. The reason for this is a more rapid saturation of the Asplanchna by unarmed prey. This causes a quicker relaxation of the predator's activities (decrease of the swimming speed, number of prey caught per collision, and number of prey swallowed per catch). In Asplanchna feeding on short-spined prey, saturation is slower but at the same time the predator's activities decrease more slowly, too (see Fig. 4). By extending the periods of exposition the survival chances of spined and spineless animals become more similar. c) In the presence of spineless animals (Brachionus rubens) as an alternative prey, the protection of the spines (in relation to spineless controls) becomes more important, because in this case the unarmed alternative prey makes a higher proportion of the predator's diet. This is true over a wide range of predation pressure (see Tables 6 and 7). d) Protective spinesara also present in juvenile B. calyciflorus. However, the juveniles are in all of their categories of spine length more sensitive to predator attacks than are corresponding adult females. The reason for this is the smaller overall body size of these animal (Tables 3, 4, 5, 6, Fig. 4). 4. The connexions between the inductive factors and the adaptive values of the cyclomorphic spine production are reviewed and discussed.
 ...
PMID:[The adaptive value of cyclomorphic spine production in Brachionus calyciflorus pallas (rotatoria) : I. Predator-prey relationships in short term experiments]. 2831 Sep 74