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191.
Walter A. Zygmunt 《Applied microbiology》1964,12(3):195-196
Production of oxytetracycline by Streptomyces rimosus in several chemically defined media containing graded concentrations of inorganic phosphorus was studied in shake flasks. Although high levels of inorganic phosphate have been reported to inhibit oxytetracycline formation, this study indicated that composition of the medium is an important factor in determining whether antibiotic production will be stimulated or inhibited by specific concentrations of inorganic phosphate. 相似文献
192.
Characterization of Clostridium perfringens (welchii) Isolated from Market Poultry 总被引:4,自引:2,他引:2 下载免费PDF全文
Richard Yamamoto Walter W. Sadler Henry E. Adler George F. Stewart 《Applied microbiology》1961,9(4):337-342
Strains of Clostridium perfringens capable of producing heat-resistant spores, characteristic of the food-poisoning types, were not recovered in a random survey of feces and livers of market poultry. Favorable growth response with a known food-poisoning strain indicated that the media and methods employed were adequate. Spores produced in vitro from this strain survived at 100 C for several hours. Animal feeding experiments with this strain showed that heat-resistant spores (surviving for 1 hr at 100 C) could be readily demonstrated 24 hr after oral instillation of vegetative cells in mouse feces, but not in chicken feces. One experiment suggests that this strain might adapt to the environment of the intestinal tract of chickens, but not all of the spores recovered were as heat resistant as those of the parent culture. 相似文献
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Walter R. Stahl 《Bulletin of mathematical biology》1961,23(4):355-376
Dimensional analysis is discussed from the viewpoint of its basic group properties and shown to be an algebraic Abelian group
that is useful for analysis of physical measurements. The application of the method to various types of equations and the
formulation of previously unclassified dimensions are discussed. Functional dimensional analysis is applied to the problems
of cell size and biomass proliferation; future applications are also noted. A number of dimensionless terms have been formulated
for cellular physiochemical phenomena. They apparently represent the first systematic study of biological dimensionless numbers
recorded in the literature. A dimensionless proliferation law is suggested. A brief analysis of the physical dimensionality
associated with information measures is carried out. Entropy and “information” are shown to be completely different in their
dimensional meaning; other informational measures of possible interest in biology are proposed. The dimensional coding and
computor analysis of biomathematical equations is suggested. 相似文献
195.
An Electron Microscope Study of Intranuclear Inclusions in Mouse Liver and Hepatoma 总被引:8,自引:0,他引:8 下载免费PDF全文
An electron microscope study of intranuclear inclusions which occur in giant cells in a transplantable mouse hepatoma and in enlarged liver cells in mice fed a diet containing bentonite demonstrates that these inclusions are formed by invaginations of the nuclear envelope, and corroborates a previous histochemical study which revealed that the contents of the inclusions are of cytoplasmic origin. In the hepatoma cells the intranuclear inclusions are abundant, small, and situated close to the border of the nucleus, and there are wide openings from the cytoplasm into the invaginations whose contents include lipid droplets, ergastoplasm, and structurally normal mitochondria. In the enlarged liver cells the inclusions are fewer in number, generally much larger than those in the hepatoma, hence they extend deeper into the nucleus, and the interior is continuous with the cytoplasm through only a small opening. Some normal ergastoplasm is present within the inclusions but all other constituents are abnormal. Both normal and degenerating mitochondria occur in the cytoplasm but only degenerating ones are found within the inclusions. Both types of inclusions arise in greatly enlarged cells in which an attempt is made to maintain the normal nuclear surface/nuclear volume ratio by the development of the invaginations of the nuclear envelope. 相似文献
196.
Walter R. MacLaren 《The Western journal of medicine》1959,91(5):278-282
A flavored solution containing 80 mg. of theophylline and 3 cc. of ethyl alcohol per 15 cc. was given orally to 31 patients with acute asthma to terminate the attack. Thirty patients with moderate to severe chronic asthma were alternated for three or four weeks on daily multiple doses of either the theophylline solution or a placebo.In the acute cases three-second Vital Capacity increased by 33.8 per cent and Maximal Breathing Capacity by 30.2 per cent in one hour after taking 60 cc. to 75 cc. of the theophylline solution. When placebos were given, both measures of lung function declined during the first half hour.Seventy-one and a half per cent of patients with acute cases felt moderate to complete relief of symptoms. In persons with chronic asthma the regular use of the theophylline solution did not change the frequency of asthma in most cases, but it decreased the severity in 59 per cent of cases. The values for three-second Vital Capacity and Maximal Breathing Capacity rose only a little.Gastric irritation was noted in one-third of the chronic cases and one-fourth of the acute cases. This could be reduced by appropriate measures. 相似文献
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Zusammenfassung Die an Innenepidermiszellen der Zwiebelschuppe vonAllium cepa zu beobachtenden schlauchförmigen intraplasmatischen Vakuolen, in der vorliegenden Arbeit kurz als Schläuche bezeichnet, werden näher untersucht. Sie heben sich im Protoplasma im Phasenkontrast als nichtkontrastierte, massearme Zonen ab. Diese Gebilde werden als Elemente des endoplasmatischen Retikulums (ER) angesprochen. Vergleichende Literaturstudien bekräftigen diese Ansicht.An tierischen Zellen wurden mehrfach im positiven Phasenkontrast dunkle, längliche oder netzförmige Gebilde als Elemente des ER erkannt. Die bei Pflanzenzellen auftretenden, äußerlich sehr ähnlichen Gebilde sind dagegen Plasmaleisten. Sie entstehen zwischen vergrößerten vakuolenartigen Elementen des ER.In jedem Fall ist es notwendig, streng zwischen dem ER sensu strictu, welches aus den Membranen und der von diesen umschlossenen intrazisternalen Phase (IZP) besteht, und dem Grundplasma, der extrazisternalen Phase (EZP), in der die Organellen liegen, zu unterscheiden. Im Lichtmikroskop (Phasenkontrast) werden an erwachsenen Pflanzenzellen die Membranen des ER nicht aufgelöst. Wenn die Membranen aber auseinanderweichen und die IZP durch Wasseraufnahme ein größeres Volumen einnimmt, kann man den Kontrastunterschied zwischen IZP und EZP sehen.Wir danken den optischen Werken C. Reichert A. G., Wien, für die leihweise Überlassung einer phasenoptischen Ausrüstung und der Firma Werfft-Chemie, Wien, für das Tetracyclin-Präparat Achromycin- Lederle. 相似文献