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71.
Summary Catalase induction in Rhodopseudomonas spheroides and three locally isolated strains of Rhodopseudomonas (TL-1, TL-4 and Rps. D) was studied. A correlation between the rate of excretion of porphyrin and the inducibility of the culture was observed. 8-hydroxyquinoline at 4x10-5 M had no effect on Bchl synthesis but it inhibited porphyrin excretion and catalase induction in Rhodopseudomonas spheroides. 8-OH Q at this concentration partially inhibited Bchl synthesis and catalase induction in strain TL-1. The data indicate that the amount of catalase produced is dependent on the pool size of porphyrins.Abbreviations used ALA
-amino laevulinic acid
- Bchl
Bacteriochlorophyll
- EDTA
Ethylene diamine tetra acetate
- DMSO
Dimethyl sulfoxide
- 8-OH Q
8-hydroxyquinoline
- nm
nanometer
-
Rh.
Rhodopseudomonas
This work is part of a thesis submitted by K. T. Shanmugam in partial fulfillment of the requirements for the Ph. D. degree. 相似文献
72.
73.
Effect of Sublethal Heat on the Metabolic Activity of Staphylococcus aureus 总被引:13,自引:4,他引:9
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Cells of Staphylococcus aureus MF-31 which have been heat-injured at 52 C have an altered metabolic activity. Analyses of whole-cell preparations by means of the Thunberg technique and Warburg manometry showed decreased dehydrogenase activity and oxygen uptake on a variety of substrates. In cell-free extracts prepared from injured cells, it was demonstrated that the specific activity of fructose diphosphate aldolase, lactate dehydrogenase, and butanediol dehydrogenase was less than that of extracts prepared from normal unheated cells. Recovery of the heat-injured cells in a suitable medium supported a return of the dehydrogenase activity and oxygen uptake, but the activity of the enzymes in cell-free extracts prepared from such partially recovered cells did not fully return to the level of normal (unheated) preparations. Addition of chloramphenicol or actinomycin D to the recovery medium, singly or in combination, retarded the return of the normal metabolic activity. Radiorespirometric experiments indicated that the percentage participation of the Embden-Meyerhoff Parnas and hexose monophosphate pathways remained the same for normal and heat-injured cells. The sublethal heat treatment decreased the catabolic capabilities of S. aureus and the production of selected end products associated with the metabolism of glucose. 相似文献
74.
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76.
Site Specifics
North Carolina State University 相似文献77.
D J Taatjes L A Barcomb K O Leslie R B Low 《The journal of histochemistry and cytochemistry》1990,38(2):233-244
We used post-embedding cytochemical techniques to investigate the lectin binding profiles of rat lung alveolar epithelial cells. Sections from rat lung embedded in the hydrophilic resin Lowicryl K4M were incubated either directly with a lectin-gold complex or with an unlabeled lectin followed by a specific glycoprotein-gold complex. The binding patterns of the five lectins used could be divided into three categories according to their reactivity with alveolar epithelial cells: (a) the Limax flavus lectin and Ricinus communis I lectin bound to both type I and type II cell plasma membranes; (b) the Helix pomatia lectin and Sambucus nigra L. lectin bound to type II but not type I cells; and (c) the Erythrina cristagalli lectin reacted with type I cells but was unreactive with type II cells. The specificity of staining was assessed by control experiments, including pre-absorption of the lectins with various oligosaccharides and enzymatic pre-treatment of sections with highly purified glycosidases to remove specific sugar residues. The results demonstrate that these lectins can be used to distinguish between type I and type II cells and would therefore be useful probes for investigating cell dynamics during lung development and remodeling. 相似文献
78.
The origin of polynucleotide-directed protein synthesis 总被引:7,自引:0,他引:7
Leslie E. Orgel 《Journal of molecular evolution》1989,29(6):465-474
Summary If protein synthesis evolved in an RNA world it was probably preceded by simpler processes by means of which interaction with
amino acids conferred selective advantage on replicating RNA molecules. It is suggested that, at first, the simple attachment
of amino acids to the 2′(3′)-termini of RNA templates favored initiation of replication at the end of the template rather
than at internal positions. The second stage in the evolution of protein synthesis would probably have been the association
of pairs of charged RNA adaptors in such a way as to favor noncoded formation of peptides. Only after this process had become
efficient could coded synthesis have begun. 相似文献
79.
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
80.
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