scholarly journals FURTHER OBSERVATIONS ON THE BEHAVIOR OF STAPHYLOCOCCI WITHIN HUMAN LEUKOCYTES

1960 ◽  
Vol 111 (4) ◽  
pp. 533-558 ◽  
Author(s):  
David E. Rogers ◽  
Marian Ann Melly
Keyword(s):  
Heat Stability ◽  
Test System ◽  
Rabbit Serum ◽  
Heat Inactivation ◽  
Coagulase Negative Staphylococci ◽  
Opsonic Activity ◽  
Fresh Serum ◽  
Large Populations ◽  
Two Factors ◽  
Homologous Strain

A specific serum factor was required for rapid phagocytosis of pathogenic staphylococci by human polymorphonuclear leukocytes when the ingestion process was studied in siliconed glass systems and the concentrations of staphylococci were maintained at low levels. In contrast to certain other microbes, the resistance to phagocytosis which characterized pathogenic staphylococci was relative, and phagocytosis was readily accomplished when large populations of staphylococci were present in the test system. A factor promoting phagocytosis was present in eight of eight normal adult sera. In contrast, the sera of twenty-eight of thirty normal rabbits did not promote phagocytosis. Serum obtained from 2 rabbits maintained in the rabbit colony for several months acquired the ability to opsonize pathogenic staphylococci. The phagocytosis-promoting factor was almost completely removed by prior absorption of test sera with the homologous strain. The factor was incompletely removed by absorption with heterologous strains of pathogenic staphylococci and was not significantly reduced by absorption with coagulase-negative staphylococci or unrelated microorganisms. Present evidence suggests that the factor promoting phagocytosis is a thermostable opsonin. While the activity of heated serum could not be restored by the addition of small amounts of fresh serum or complement, the addition of large amounts of complement partially restored opsonic activity. Incubation of staphylococci in fresh serum prior to heat inactivation did not reduce subsequent phagocytosis, further suggesting the heat stability of the phagocytosis-promoting factor. Preliminary studies correlating the presence of antistaphylococcal hemagglutinins and phagocytosis-promoting factor in certain sera suggest that the two factors were not necessarily related. The phagocytosis of staphylococci in fresh human serum was inhibited by the addition of fresh or inactivated rabbit serum. Further studies on the nature of such inhibition are in progress. Once ingestion was accomplished, coagulase-positive staphylococci consistently survived in significant numbers within the cytoplasm of human granulocytes. Coagulase-negative staphylococci appeared to be destroyed within the leukocyte and could not be recultured from the cytoplasm following 3 to 4 hours of intracellular residence.

scholarly journals DNA Genome Size Affects the Stability of the Adenovirus Virion

2008 ◽  
Vol 83 (4) ◽  
pp. 2025-2028 ◽  
Author(s):  
Adam C. Smith ◽  
Kathy L. Poulin ◽  
Robin J. Parks
Keyword(s):  
Genome Size ◽  
Critical Role ◽  
Heat Stability ◽  
Helper Virus ◽  
Heat Inactivation ◽  
Similar Relationship ◽  
Viral Dna ◽  
A Genome ◽  
The Stability ◽  
Replication Defective Adenovirus

ABSTRACT Replication-defective adenovirus (Ad) vectors can vary considerably in genome length, but whether this affects virion stability has not been investigated. Helper-dependent Ad vectors with a genome size of ∼30 kb were 100-fold more sensitive to heat inactivation than their parental helper virus (>36 kb), and increasing the genome size of the vector significantly improved heat stability. A similar relationship between genome size and stability existed for Ad with early region 1 deleted. Loss of infectivity was due to release of vertex proteins, followed by disintegration of the capsid. Thus, not only does the viral DNA encode all of the heritable information essential for virus replication, it also plays a critical role in maintaining capsid strength and integrity.

Heat Stability of the Bile Salt-Stimulated Lipase in Human Milk Fortified with Sodium Taurocholate1

1988 ◽  
Vol 51 (4) ◽  
pp. 310-313 ◽  
Author(s):  
H. L. PAN ◽  
C. W. DILL ◽  
E. S. ALFORD ◽  
S. L. DILL ◽  
C. A. BAILEY ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Human Milk ◽  
Bile Salt ◽  
Lipase Activity ◽  
Sodium Taurocholate ◽  
Heat Stability ◽  
Heat Inactivation ◽  
Temperature Differential ◽  
Heat Stable ◽  
Control Samples

Time-temperature relationships for heat-inactivation of the bile salt-stimulated lipase activity were compared in whole human milk and in the same product fortified to 9 mM/ml with sodium taurocholate. Heat treatments were varied from 45 to 70°C for times ranging from 15s to 40 min. Enzyme activity was more heat stable in human milk fortified with taurocholate than in control samples. The temperature required for the onset of heat inactivation at 30-min holding time was increased from 45°C for control samples to 60°C following addition of taurocholate. A temperature differential of approximately 12°C was required in the fortified milks to produce inactivation equivalent to that observed in the control milks over the heating range studied.

Effect of Proline, Betaine and Some Other Solutes on the Heat Stability of Mitochondrial Enzymes

1982 ◽  
Vol 9 (1) ◽  
pp. 47 ◽  
Author(s):  
D Nash ◽  
LG Paleg ◽  
JJ Wiskich
Keyword(s):  
Malate Dehydrogenase ◽  
Isocitrate Dehydrogenase ◽  
Plant Mitochondria ◽  
Heat Stability ◽  
Heat Inactivation ◽  
Mitochondrial Enzymes

When isolated plant mitochondria are heated, isocitrate dehydrogenase, malate dehydrogenase and fumarase lose activity at different rates. The rate of loss of activity of each enzyme is reduced if the mitochondria are heated in the presence of proline, betaine or some other solutes; protection by proline or betaine against heat inactivation is also evident with these enzymes when they are solubilized. NAD-isocitrate dehydrogenase in pea mitochondria and NADP-dependent isocitrate dehydrogenase of pea chloroplasts are also protected by proline and betaine against inactivation when the isolated organelles are heated.

scholarly journals Update on clinical significance of coagulase-negative staphylococci.

1994 ◽  
Vol 7 (1) ◽  
pp. 117-140 ◽  
Author(s):  
W E Kloos ◽  
T L Bannerman
Keyword(s):  
Clinical Significance ◽  
Defense Mechanisms ◽  
Etiologic Agent ◽  
Coagulase Negative Staphylococcus ◽  
Coagulase Negative Staphylococci ◽  
Antibiotic Resistant ◽  
Molecular Approaches ◽  
Large Populations ◽  
Culture Identification ◽  
Different Strains

The clinical significance of coagulase-negative Staphylococcus species (CNS) continues to increase as strategies in medical practice lead to more invasive procedures. Hospitalized patients that are immunocompromised and/or suffering from chronic diseases are the most vulnerable to infection. Since CNS are widespread on the human body and are capable of producing very large populations, distinguishing the etiologic agent(s) from contaminating flora is a serious challenge. For this reason, culture identification should proceed to the species and strain levels. A much stronger case can be made for the identification of a CNS etiologic agent if the same strain is repeatedly isolated from a series of specimens as opposed to the isolation of different strains of one or more species. Strain identity initially can be based on colony morphology, and then one or more molecular approaches can be used to gain information on the genotype. Many of the CNS species are commonly resistant to antibiotics that are being indicated for staphylococcal infections, with the exception of vancomycin. The widespread use of antibiotics in hospitals has provided a reservoir of antibiotic-resistant genes. The main focus on mechanisms of pathogenesis has been with foreign body infections and the role of specific adhesins and slime produced by Staphylococcus epidermidis. Slime can reduce the immune response and opsonophagocytosis, thereby interfering with host defense mechanisms. As we become more aware of the various strategies used by CNS, we will be in a better position to compromise their defense mechanisms and improve treatment.

scholarly journals BACTERICIDAL ACTION OF HISTONE

1958 ◽  
Vol 108 (6) ◽  
pp. 925-944 ◽  
Author(s):  
James G. Hirsch
Keyword(s):  
Bactericidal Activity ◽  
Physiological State ◽  
Lethal Effect ◽  
Test System ◽  
Morphological Alteration ◽  
Rabbit Serum ◽  
E Coli ◽  
Lethal Action ◽  
K 12

The arginine-rich fraction of calf thymus histone (histone B) exerts bactericidal activity on various coliform bacilli and micrococci under certain conditions in vitro. Final concentrations of less than 1 µg. histone per ml. kill susceptible microbes without detectable morphological alteration or lysis. Among the microorganisms highly susceptible to histone are Escherichia, Salmonella, Shigella, Pseudomonas, Klebsiella, and Micrococcus pyogenes var. albus. Less susceptible or completely resistant are Proteus, Serratia, Micrococcus pyogenes var. aureus, and various types of hemolytic streptococci. Coliforms grown on solid media are much more resistant to the lethal effect of histone than are those cultured in liquid media. This difference is apparently related to the physiological state of the bacteria; agar grown microorganisms washed with water remain resistant to histone, whereas incubation in broth rapidly renders them more susceptible. Histone is adsorbed onto heat-killed E. coli K-12 under conditions suitable for lethal action on this organism. The bactericidal activity of histone is but little affected by pH of the test system, but ionic strength of the medium exerts a marked influence, the lethal action being reduced or blocked as the salt concentration reaches levels higher than that of 0.15–0.2 M NaCl. Relatively high concentrations of rabbit serum or of bovine plasma albumin reduce the bactericidal activity of histone in a medium at pH 7; these serum preparations are, however, essentially without effect in the test system at pH 5.6. The bactericidal effect of histone is antagonized by addition to the medium of small amounts of certain basic substances (protamine, spermine), or of various acid polysaccharides (heparin, nucleic acid, bacterial lipopolysaccharides). The rate of killing of E. coli K-12 by histone increases as the temperature and the concentration of histone are raised. Within the limits studied, this rate also appears to be directly proportional to the concentration of bacteria in the system.

scholarly journals The influence of temperature on phagocytosis

1908 ◽  
Vol 80 (539) ◽  
pp. 188-195 ◽  
Keyword(s):  
Quantitative Methods ◽  
Laboratory Strain ◽  
Polymorphonuclear Leucocyte ◽  
Complex Phenomenon ◽  
Fresh Serum ◽  
Two Factors ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
In Series ◽  
Micro Organisms

Recent work has shown that the phagocytosis of micro-organisms is a complex phenomenon, involving at least two factors, viz.: (1) the sensitisation of the micro-organism by the opsonin of the blood serum, and (2) the phagocytic act of the polymorphonuclear leucocyte. The latter function has been known for many years to be markedly influenced by temperature. It appeared desirable, however, to ascertain whether, by the modern quantitative methods employed in opsonic work, some definite relationship could be found to subsist between degree of temparature and degree of phagocytosis. In the first set of experiments no attempt was made to separate the respectively functions of sensitisation, and amœboid activity of the leucocyte. Both actions were allowed to proceed simultaneously. Consequently, in Series 1 the leucocytes were put in contact with fresh serum and micro-organisms (staphylococci), and incubated together at different temperatures for the same period of time. Thereafter the number of cocci taken up per leucocyte was calculated on stained films in the usual way. The Staphylococcus aureus employed was an old laboratory strain.

Characterization of placental isoenzyme of alkaline phosphatase in human pregnancy serum

1969 ◽  
Vol 47 (2) ◽  
pp. 147-155 ◽  
Author(s):  
N. K. Ghosh ◽  
W. H. Fishman
Keyword(s):  
Alkaline Phosphatase ◽  
Serum Alkaline Phosphatase ◽  
Heat Stability ◽  
Biochemical Properties ◽  
Heat Inactivation ◽  
Total Serum ◽  
Placental Alkaline Phosphatase ◽  
Human Placental Alkaline Phosphatase ◽  
Alkaline Phosphatase Isoenzyme ◽  
In Pregnancy

Human placental alkaline phosphatase isoenzyme has been characterized in pregnancy serum by several biochemical criteria. The total serum alkaline phosphatase, its L-phenylalanine-sensitive moiety, heat inactivation, and the ratio of enzyme activity at pH 10.7 versus 9.8 (10.7/9.8 R) were measured during parturition and 59 weeks of pre- and post-natal periods. The extent of L-phenylalanine inhibition, heat stability, and 10.7/9.8 R of serum alkaline phosphatase progressively increased during gestation attaining maximum values during the delivery, after which they gradually declined. The electrophoretic behaviors of alkaline phosphatase isoenzymes of pregnancy sera were followed by starch- and Sephadex-gel electrophoreses. Alkaline phosphatase has been purified 300-fold from the placenta of the subject whose serum enzyme was investigated. The biochemical properties, including the electrophoretic behavior and neuraminidase sensitivity of heat-stable alkaline phosphastase in pregnancy sera at term, were comparable to those of purified placental alkaline phosphatase. The values for 10.7/9.8 R of the pregnancy sera were statistically different from those of sera from normal nonpregnant women. The results obtained in this study suggest that the enhanced level of pregnancy serum alkaline phosphatase is due to the enrichment of the circulation with an isoenzyme of placental origin.

scholarly journals Influence of rearing system on growth of bulls in performance test

2002 ◽  
Vol 18 (1-2) ◽  
pp. 3-10
Author(s):  
Vladan Bogdanovic ◽  
Milan Petrovic
Keyword(s):  
Performance Test ◽  
Growth Traits ◽  
Statistical Significance ◽  
Average Daily Gain ◽  
Test System ◽  
Two Factors ◽  
Origin Group ◽  
Sources Of Variation ◽  
Beef Bulls

Data on 643 beef bulls were used in order to analyze influence of rearing system or herd of origin on growth traits (average daily gain and body masses) of beef bulls in performance test (Marchigiana, n= 181, Chianina, n=240, Romagnola, n=222). Several fixed or random effects, such as breed, type of rearing or herd of origin, group, parity and twinning, were included in two statistical models. According to rearing system (in stall, on pasture or mixed) it should be pointed out that several different sources of variation for growth traits evince statistical significance. Also, herd of origin represents very significant source of variation for all included traits. The main difference between those two factors (type of rearing system or herd of origin) is that influence of rearing system decreased during the test, while the effect of herd of origin remained until the end of test. It was concluded that the adequate determination of non-genetic sources of variation referring to the pre-test system of rearing might be of crucial importance for ranking potential sires.

scholarly journals Diminished Adherence and/or Ingestion of VirulentMycobacterium tuberculosis by Monocyte-Derived Macrophages from Patients with Tuberculosis

1998 ◽  
Vol 5 (5) ◽  
pp. 690-694 ◽  
Author(s):  
J. Zabaleta ◽  
M. Arias ◽  
J. R. Maya ◽  
L. F. García
Keyword(s):  
Flow Cytometry ◽  
Mycobacterium Tuberculosis ◽  
Human Monocyte ◽  
Heat Inactivation ◽  
Microscopical Examination ◽  
Healthy Controls ◽  
Complement Receptors ◽  
Edta Treatment ◽  
Fresh Serum ◽  
Associated Proteins

ABSTRACT The interaction between the macrophage and Mycobacterium tuberculosis is mediated by a variety of macrophage membrane-associated proteins. Complement receptors have been implicated in the adherence of M. tuberculosis to macrophages. In the present work, the adherence and/or ingestion of M. tuberculosis H37Rv to human monocyte-derived macrophages (MDM) from patients with tuberculosis (TB) and healthy controls was measured by microscopical examination, [3H]uracil incorporation, and CFU. The adherence and/or ingestion was enhanced by fresh serum and inhibited by heat inactivation, EDTA treatment, and anti-CR1 and anti-CR3 antibodies. Comparison of MDM from TB patients and healthy controls showed that the former exhibited a significantly decreased capacity to adhere and/or ingest M. tuberculosis, as determined by the number of CFU and 3H incorporation. The expression of CR1 (CD35) and CR3 (CD11b/CD18) on MDM from TB patients and healthy controls, as determined by flow cytometry, did not show significant differences. These results suggest that the lower ingestion of M. tuberculosis by MDM from TB patients is not due to defects in complement receptors, and therefore, there might be other molecules involved in the adherence and/or ingestion process that render MDM from TB patients ingest less mycobacteria than those from healthy controls.

scholarly journals THE CHEMOTACTIC EFFECT OF MIXTURES OF ANTIBODY AND ANTIGEN ON POLYMORPHONUCLEAR LEUCOCYTES

1962 ◽  
Vol 115 (3) ◽  
pp. 453-466 ◽  
Author(s):  
Stephen Boyden
Keyword(s):  
Chemotactic Activity ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Polymorphonuclear Leucocytes ◽  
Heat Stable ◽  
Motile Cells ◽  
Fresh Serum ◽  
In Vitro Technique ◽  
Chemotactic Effect

An in vitro technique is described for assessing the chemotactic activity of soluble substances on motile cells. Antibody-antigen mixtures when incubated (37°C) in medium containing fresh (i.e. non-inactivated) normal rabbit serum exert a strong chemotactic effect on rabbit polymorphonuclear leucocytes. Results are described which indicate that, when antibody-antigen complexes are incubated (37°C) in fresh serum, a heat-stable (56°C) substance (or substances) is produced which acts directly as a chemotactic stimulus on the polymorphs. This heat-stable chemotactic substance is not produced when antibody-antigen complexes are incubated in serum which has been heated at 56°C for 30 minutes.

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