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Biomedical subjects

L Baumann

Publications and source records attributed to L Baumann.

67 records · Page 4Linked to original sources
PubMed1975

Catabolism of D-fructose and D-ribose by Pseudomonas doudoroffii. I. Physiological studies and mutant analysis.

Pseudomonas doudoroffii, a strict aerobe of marine origin, was able to utilize fructose and ribose but not glucose, gluconate, or other hexoses, pentoses, or sugar alcohols as sole sources of carbon and energy. Evidence was presented indicating that in this organism fructose was utilized via an inducible P-enolpyruvate: fructose phosphotransferase system (FPTS) which catalyzed the phosphorylation of fructose in the 1 position. The resulting fructose-1-P (F-1-P) was converted to fructose-1,6-P2 (FDP) by means of an inducible 1-P-fructokinase (1-PFK). The subsequent conversion of FDP to pyruvate involved enzymes of the Embden-Meyerhof pathway (EMP) which, with the exception of glyceraldehyde-3-P dehydrogenase (G3PDH), were constitutive. Two G3PDH activities were detected, one of which was inducible and NAD-dependent while the other was constitutive and NADP-dependent. Cell-free extracts of P. doudoroffii also contained enzymes of the methylglyoxal pathway (MGP) which converted dihydroxyacetone-P to pyruvate. The low specific activities of enzymes of this pathway as compared to the EMP suggested that the major route of FDP catabolism was via the latter pathway. 2. Ribose catabolism appeared to involve an inducible uptake system and an inducible ribokinase, the resulting ribose-5-P being converted to glyceraldehyde-3-P and fructose-6-P (F-6-P) by means of constitutive activities of the pentose-P pathway. The F-6-P formed as a result of these reactions was converted to FDP by means of a constitutive 6-P-fructokinase (6-PFK). Since no activity converting fructose or F-1-P to F-6-P could be detected in cell-free extracts of P. doudoroffii, the results suggested that fructose and ribose were catabolized via 1-PFK and 6-PFK, respectively, the two pathways converging at the level of FDP. Further evidence for this suggestion was obtained from a mutant which lacked an NAD-dependent G3PDH, accumulated FDP from both fructose and ribose, and was not able to grow on either of these compounds. 3. Ribose grown cells had increased amounts of the fructose uptake system and 1-PFK suggesting that a compound (or compounds) common to the catabolism of both fructose and ribose acted as the inducer(s) of these activities. Evidence was presented suggesting that the probable inducer(s) of 1-PFK and FPTS could be FDP, glyceraldehyde-3-P, or dihydroxyacetone-P. 4. A mutant unable to grow on fructose was characterized and found to lack FPTS while retaining 1-PFK and other enzyme activities of the EMP and MGP, indicating that a functional FPTS was essential for growth on fructose and suggesting that all or most of this sugar was catabolized via F-1-P.

Dihydroxyacetone Phosphate↗
PubMed1975

Catabolism of D-fructose and D-ribose by Pseudomonas doudoroffii. II. Properties of 1-phosphofructokinase and 6-phosphofructokinase.

1. The 1-P-fructokinase (1-PFK) and 6-P-fructokinase (6-PFK) from Pseudmonas doudoroffii were partially purified by a combination of (NH4)2SO4 fractionation and DEAE-Sephadex column chromatography. The pH optima of these enzymes were 9.0 and 8.5, respectively. 2. When the concentrations of the substrates of the 1-PFK reaction were varied, Michaelis-Menten kinetics were observed. The Kms for D-fructose-1-P (F-1-P) and ATP were 3.03 X 10(-4) M and 3.39 X 10(-4) M, respectively. Variation of MgCl2 at fixed concentrations of F-1-P and ATP resulted in sigmoidal kinetics; about 10 mM MgCl2 was necessary for maximal activity. Activity of 1-PFK was inhibited when the ratio of ATP:Mg++ was higher than 0.5, suggesting that ATP:2Mg++ was the substrate and that free ATP was inhibitory. Although an absolute requirement for K+ or NH4+ could not be demonstrated, these cations stimulated the rate of the reaction. Activity of 1-PFK was not significantly affected by 3 mM AMP, cyclic-AMP, Pi, D-fructose-6-P (F-6-P), ADP, P-enolpyruvate (PEP), pyruvate, citrate, or L-gluamate. 3. Sigmoidal kinetics were observed for 6-PFK when the concentration of F-6-P was increased and the level of ATP was kept constant. Activity of 6-PFK was increased by ADP, inhibited by PEP, and unaffected by 3 mM AMP, cyclic-AMP, Pi, F-1-P, pyruvate, or citrate.

Adenosine Triphosphate↗
PubMed1975

Enzymes of D-fructose catabolism in species of Beneckea and Photobacterium.

Cell-free extracts of strains representative of the genera Beneckea and Photobacterium catalyzed a P-enolpyruvate dependent phosphorylation of D-fructose. The resulting product, fructose-1-P, was converted to fructose-1,6-P2 by 1-P-fructokinase. Both activities were inducible, being present in D-fructose-grown cells and reduced or absent in D-gluconate-(or succinate-) grown cells.

Adenosine Triphosphate↗
PubMed1975

5-Hydroxytryptamine and learning: long-term effects of P-chloroamphetamine on acquisition.

The effect of p-chloroamphetamine (PCA) on the acquisition of a conditioned avoidance response in the rat was examined. Eleven rats were injected with saline or 2 X 10 mg/kg of PCA i.p. on two consecutive days and the learning procedure was started eight days later and lasted for six days. The acquisition of the conditioned avoidance response was strongly impaired by PCA compared with the control group. It is suggested that the impaired learning is due to a long-term effect of PCA on a 5-hydroxytryptamine system directly or indirectly linked to learning.

Amphetamines↗
PubMed1973

Taxonomy of marine bacteria: Beneckea parahaemolytica and Beneckea alginolytica.

A collection of 169 strains, including 91 obtained from cases of gastroenteritis and 41 from localized tissue infections and infections of the eye and ear, was submitted to an extensive nutritional, physiological, and morphological characterization. The nutritional and physiological data obtained from these strains, as well as data for strains of other species of the genus Beneckea, were submitted to a numerical analysis which grouped the strains into clusters on the basis of phenotypic similarity. Strains from cases of gastroenteritis formed a group of three clusters which linked at a similarity value of 68%. These three clusters could not, however, be separated from each other by universally positive or negative traits, and on the basis of their overall phenotypic similarity were assigned to a single species, B. parahaemolytica. The majority of the strains from human, nonenteric sources segregated into two distinct clusters, one designated B. alginolytica and the other unassigned with respect to species (group C-2). B. parahaemolytica, B. alginolytica, and group C-2 could be readily distinguished from one another as well as from the remaining species of the genus Beneckea by multiple, unrelated, phenotypic traits. Activities of selected enzymes of glucose and gluconate catabolism in cell-free extracts of B. parahaemolytica, B. alginolytica, and group C-2 suggested that these organisms utilized glucose primarily via the Embden-Meyerhof pathway and gluconate primarily via the Entner-Doudoroff pathway. Similar results were observed in the other members of the genus Beneckea.

Bacteria↗
PubMed1972

Taxonomy of aerobic marine eubacteria.

Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are discussed.

Alcaligenes↗
PubMed1971

Taxonomy of marine bacteria: the genus Beneckea.

One-hundred-and-forty-five isolates of marine origin were submitted to an extensive physiological, nutritional, and morphological characterization. All strains were gram-negative, facultatively anaerobic, straight or curved rods which were motile by means of flagella. Glucose was fermented with the production of acid but no gas. Sodium but no organic growth factors were required. None of the strains were able to denitrify or fix molecular nitrogen. The results of nutritional and physiological tests were submitted to a numerical analysis. On the basis of phenotypic similarity, nine groups were established. These groups could be distinguished from one another by multiple, unrelated, phenotypic traits. Six groups which had deoxyribonucleic acid (DNA) containing 45 to 48 moles per cent guanine plus cytosine (GC) were assigned to a redefined genus Beneckea. All of the strains in this genus, when grown in liquid medium, had a single, polar flagellum. When grown on a solid medium, many strains had peritrichous flagella. Two groups were similar to previously described species and were designated B. alginolytica and B. natriegens. The remaining four groups were designated B. campbellii, B. neptuna, B. nereida, and B. pelagia. An additional group of phenotypically similar strains having the properties of the genus Beneckea was not included in the numerical analysis. These strains were readily separable from species of this genus and were designated B. parahaemolytica. Of the remaining groups, one was identified as Photobacterium fischeri. The other group (B-2) which had about 41 moles% GC content in its DNA could not be placed into existing genera.

Acids↗
PubMed1971

Taxonomy of marine bacteria: Beneckea nigrapulchrituda sp. n.

Fourteen bacterial strains of marine origin, which formed colonies containing crystals of a blue-black pigment, were submitted to a morphological, physiological, and nutritional characterization. The results indicated that these organisms form a new species of the genus Beneckea.

Amino Acids↗
PubMedDate not supplied

Risk of transmission of sexually transmitted diseases by cryopreserved semen.

The increasing incidence of sexually transmitted diseases (STD) involves the risk of the transmission of these diseases by the artificial insemination. Therefore the cryotolerance of several microorganisms causing STD and the efficiency of penicillin of the cryoprotective medium (CMP) against Neisseria gonorrhoeae (N.g.) were investigated. The results have shown that penicillinase-producing N.g. (PPNG), genital mycoplasmas and Candida species survive the cryopreservation. Trichomonas vaginalis could not be recultivated after our temperature-time-regimen of the cryopreserving process. CPM with penicillin was unable to prevent a transmission of penicillin-sensitive N.g.

Candida↗