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J Guinea

Publications and source records attributed to J Guinea.

At least 37 records · Page 2Linked to original sources
PubMed1997

Assembly Properties of a Glycoprotein Produced by Pseudoalteromonas antarctica, NF3

The self-assembly properties of an extracellular material of glycoprotein character produced by a new Gram-negative species, NF3, Pseudoalteromonas antarctica, isolated from muddy soil samples of Antarctica have been investigated. The aggregation behavior of this exopolymer was studied directly by transmission electron microscopy (TEM) and analysis of digitalized TEM images of its aqueous dispersions before and after sonication. Increasing amounts of glycoprotein (GP) in water led to an abrupt decrease in the dispersion surface tensions up to a GP concentration of about 0.20 mg/ml (from 72 to 47 mN m-1), followed by an almost constant surface tension value. The size distribution curves of the aggregates formed always showed a bimodal distribution. The mean size of these two aggregates increased as GP concentration increased (first peak from 120 to 140 nm and second peak from 500 to 700 nm), reaching in both cases almost a constant value also for 0.20 mg of GP/ml of water. TEM images of unsonicated aqueous GP dispersions at concentrations lower and higher than 0.20 mg/ml always showed the coexistence of concentric multilamellar and small unilamellar aggregates, the small particles being the dominant class in the first case. Sonication of these dispersions revealed that each lamella of the initial multilamellar structures was made up of various subunits of coiled coil, whereas the smaller particles were not composed of these subunits. Profiles from digitalized TEM images of unsonicated and sonicated dispersions confirm that each lamella of large aggregates was composed of three subunits. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Pseudoalteromonas antarctica sp. nov., isolated from an Antarctic coastal environment.

The taxonomic characteristics of five bacterial strains which were isolated from Antarctic coastal marine environments were studied. These bacteria were psychrotrophic, aerobic, and gram negative with polar flagella. The G + C contents of the DNAs of these strains were 41 to 42 mol%. The Antarctic strains were phenotypically distinct from the previously described Pseudoalteromonas type species. DNA-DNA hybridization experiments revealed that the new strains were closely related to each other but clearly different from Pseudoalteromonas haloplanktis and Pseudoalteromonas atlantica, which were the most phenotypically similar organisms. None of the bacterial isolates was capable of using DL-malate, D-sorbitol, or m-hydroxybenzoate, and all were capable of gelatin hydrolysis. Strains NF2, NF3T (T = type strain), NF13, NF14, and EN10 had an Na+ requirement but required only 17 mM Na+. Phenotypic, DNA G + C content, DNA-DNA hybridization, 16S rRNA analysis, fatty acid composition, and protein profile data confirmed the identification of the Antarctic strains as members of a Pseudoalteromonas sp. The name Pseudoalteromonas antarctica sp. nov. is proposed for these organisms.

Antarctic Regions↗
PubMed1996

Antibacterial activity and pharmacokinetics of four new 7-azetidinyl fluoroquinolones.

The activity of E-4535, E-4534, E-4528, and E-4527, four new 7-azetidinyl-6-fluoroquinolones, was studied to evaluate the role played by the C-2' and C-3' substitutions of the azetidinyl group, together with a C-8 fluorine atom. In general, like other 6,8-difluoroquinolones, E-4534 and E-4527 showed higher levels of activity than the corresponding monofluorinated derivatives, E-4535 and E-4528. E-4535 and E-4534, having a 7-(2-methyl-3-aminoazetidinyl) substituent, demonstrated higher levels of activity in vitro than their corresponding structural analogs, E-4528 and E-4527, distinguished by a 3-methyl-3-methylaminoazetidinyl group at position 7 of the quinolone nucleus. In consequence, E-4534 was the most potent of the new agents tested.

Animals↗
PubMed1995

E-4695, a new C-7 azetidinyl fluoronaphthyridine with enhanced activity against gram-positive and anaerobic pathogens.

E-4695, (-)-7-[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-cyclopropyl-1,4- dihydro-6-fluoro-4-oxo-1,8-naphthyridine-3-carboxylic acid, is a new fluorinated naphthyridine with an azetidine moiety. The MICs of E-4695 at which 90% of the isolates were inhibited (MIC90s) were 0.06 to 0.5 microgram/ml for gram-positive cocci, including species of the genera Staphylococcus, Streptococcus, and Enterococcus, and the MIC90s against gram-negative pathogens such as members of the family Enterobacteriaceae (with the exception of Providencia spp. [MIC90, 8 micrograms/ml]) and Pseudomonas aeruginosa were 0.015 to 0.5 microgram/ml. E-4695 inhibited 90% of the Clostridium perfringens and Bacteroides fragilis isolates at 0.25 and 4 micrograms/ml, respectively. Against gram-positive cocci the potency of E-4695 was 2- to 8-fold higher than that of ciprofloxacin, 4- to 8-fold higher than that of ofloxacin, and 8- to 16-fold higher than that of fleroxacin. Against enteric bacteria and P. aeruginosa the potency of E-4695 was, in general, similar to that of ciprofloxacin and eightfold higher than those of ofloxacin and fleroxacin. E-4695 was four- and eightfold more potent than ciprofloxacin against C. perfringens and B. fragilis isolates, respectively. E-4695 and ciprofloxacin showed similar properties when the effects of pH or magnesium concentration were tested on them. E-4695 and ciprofloxacin had substantial reductions of activity only when pH decreased below 4.8. E-4695 and ciprofloxacin activities were not markedly affected by the presence of 5 or 10 mM Mg2+. The presence of serum and human urine at pH 7.2 decreased the activity of E-4695 between two- and fourfold. After an oral dose of 50 mg/kg of body weight, the maximum level in serum, the biological half-life, and the area under the concentration-time curve from 0 to 10 h for E-4695 were 13.2 microgram/ml, 3.3 h, and 45.6 microgram . h/ml, respectively. The area under the concentration-time curve from 0 to 4 h for ciprofloxacin was 2.3 microgram . h/ml at the same dose. Fifty-percent effective doses (ED50S) against Staphylococcus aureus HS-93 infections in mice were 4.5 mg/kg with E-4695 and 37.6 mg/kg with ciprofloxacin. Infection with Streptococcus pneumoniae 29206 was more effectively treated with E-4695 (ED50, 41,2 mg/kg) than with ciprofloxacin (ED50, 200 mg/kg). The ED50 of E-4695 for infections with Streptococcus pneumoniae 1625 was 132.2 mg/kg; ciprofloxacin was ineffective at 400 mg/kg against this strain. E-4695 was also more potent than ciprofloxacin in treatment of infections caused by gram-negative organisms such as Escherichia coli HM-42 (ED50S, 1.0 and 3.9 mg/kg, respectively). The ED50S of E-4695 and ciprofloxacin were 33.0 and 145.5 mg/kg against P. aeruginosa HS-116 and 9.6 and 18.9 mg/kg against P. aeruginosa B-120, respectively. The therapeutic efficacy of E-4695 may depend not only on its in vitro activity but also on its improved pharmacokinetic properties.

Animals↗
PubMed1994

[Study of 164 episodes of infectious endocarditis in drug addicts: comparison of HIV positive and negative patients].

OBJECTIVE: Intravenous drug-addicts (IVDA) are the most important risk group for acquiring HIV and developing infective endocarditis (IE) in Spain. The clinical and evolutive features of a large series of IE in HIV-infected IVDA are reported and compared with those observed in a smaller group of patients without HIV infection. METHODS: A retrospective analysis was made of 164 episodes of IE from 136 patients diagnosed in a Service of Infectious Diseases in Madrid (1986-1992). IE was defined according to the modified Von Reyn criteria and only the probable and definite IE episodes were evaluated. RESULTS: A total of 143 IE episodes occurred in 117 IVDA infected with HIV (group A) and 21 episodes in 19 HIV-negative patients (group B). Most of seropositive patients were asymptomatic carriers of HIV (54%) and only 22% had AIDS. The IE onset was acute for 97% patients in group A and 81% in group B, with fever and respiratory symptoms as main complaints. Chest X-ray was normal in 19% of cases in group A and in 28% in group B. Septic embolisms were observed in 56% and 41% of patients in group A and B, respectively. The vegetation originated mainly on the tricuspid valve and Staphylococcus aureus was recovered from most blood-cultures. The mortality rate was similar in both groups, 6% and 5% in groups A and B, respectively. CONCLUSIONS: Most IVDA with IE were HIV-positive patients in this series. IE is usually reported in the early stages of HIV infection and apparently its presence has no influence on the clinical course of IE.

Acquired Immunodeficiency Syndrome↗
PubMed1993

In vitro and in vivo antibacterial activities of E-4868, a new fluoroquinolone with a 7-azetidin ring substituent.

E-4868, (-)-7-[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-(2,4- difluorophenyl)-1,4-dihydro-6-fluoro-4-oxo-3-quinolinecarboxylic acid, is a new fluoroquinolone with an azetidine moiety at the 7 position. The in vitro activity of E-4868 has been compared with those of ciprofloxacin, ofloxacin, and fleroxacin, while the activity of ciprofloxacin was used as reference for in vivo studies. The MICs of E-4868 for 90% of the isolates tested (MIC90s) were 0.06 to 0.5 microgram/ml against gram-positive organisms, including Staphylococcus, Streptococcus, and Enterococcus spp. In general, the in vitro potency of E-4868 against gram-positive bacteria was higher than those of all of the other fluoroquinolones tested. MIC90s against members of the family Enterobacteriaceae between 0.03 and 1 microgram/ml were observed, with the exception of those against Serratia marcescens and Providencia spp., and a MIC90 of 2 micrograms/ml against Pseudomonas aeruginosa was obtained. E-4868 inhibited 90% of the Clostridium spp. and Bacteroides spp. at 2 micrograms/ml and was twofold more active than ciprofloxacin. An increase in the Mg2+ concentration from 1 to 10 mM increased the MIC between two and three times. Human urine caused a significant decrease in activity of E-4868, which was more pronounced at pH 5.5 than at pH 7.2. The presence of serum also decreased the activity of E-4868. Fifty percent effective dose (ED50) values against experimental Escherichia coli HM-42 infections in mice were 3.9 mg/kg of body weight with E-4868 and 3.5 mg/kg of body weight with ciprofloxacin. Corresponding ED50 values against P. aeruginosa HS-116 were 93.2 and 107.8 mg/kg, respectively, and those against Staphylococcus aureus HS-93 were 6.5 and 44.6 mg/kg, respectively. In experimental infections with Streptococcus pneumoniae 84551, the ED50 value of E-4868 was 154.4 mg/kg, while ciprofloxacin proved totally inactive at a dose of 400 mg/kg. When E-4868 was administered orally at a dose of 50 mg/kg in mice, the area under the concentration-time curve (0 to 4 h) value was 28.4 microgram . h/ml, while an area under the concentration-time curve value of 2.3 microgram . h/ml was observed for ciprofloxacin at the same dose. In these studies, levels of the two agents in blood 1 h postadministration were 7.6 and 1.2 microgram/ml, respectively.

Animals↗
PubMed1991

R-bodies in Pseudomonas aeruginosa strain 44T1.

For the first time R-bodies are described in a new strain 44T1 of Pseudomonas aeruginosa. Its size was measured as being 0.22 to 0.37 microns of width per 0.27 to 0.41 microns of length and 5 to 9 spiral turns about 16 nm. These structures are similar to previously observed in bacteria and are related with physiological state of bacteria in minimal conditions of growth.

Bacterial Proteins↗
PubMed1991

In vitro and in vivo antibacterial activities of E-4497, a new 3-amine-3-methyl-azetidinyl tricyclic fluoroquinolone.

The in vitro and in vivo antibacterial activities of a new tricyclic fluoroquinolone, E-4497 [S(-)-9-fluoro-3-methyl-10-(3-amine-3-methyl-azetidin-1-yl)-7-oxo- 2,3-dihydro- 7H-pyrido-(1,2,3-de)-1,4-benzoxazine-6-carboxylic acid], were evaluated in comparison with those of DR-3355 [S-(-)-ofloxacin], norfloxacin, and ciprofloxacin. E-4497 was more potent than norfloxacin and as potent as or more potent than DR-3355 and ciprofloxacin against Staphylococcus spp., Streptococcus spp., and Enterococcus faecalis. With the exception of Providencia spp., E-4497 inhibited 90% of the Enterobacteriaceae at less than or equal to 0.25 micrograms/ml. Against enteric bacteria, E-4497 was similar in potency to norfloxacin but less potent than DR-3355 and ciprofloxacin. For Pseudomonas aeruginosa, the MICs of E-4497, DR-3355, norfloxacin, and ciprofloxacin for 90% of strains were 2, 2, 4, and 0.5 micrograms/ml, respectively. Against Clostridium perfringens and Bacteroides fragilis, E-4497 (MICs for 90% of strains, 2 and 8 micrograms/ml, respectively) was two- to fourfold more active than norfloxacin and ciprofloxacin. E-4497 activity decreased moderately in the presence of 10 mM Mg2+. Urine at pH 5.5 caused a significant decrease in activity compared with urine at pH 7.2. However, the presence of serum either had no effect or increased the activity of E-4497. In general, E-4497 was bactericidal at the MIC. In systemic infections with Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, and Pseudomonas aeruginosa in mice, the protective effect of E-4497 was generally greater than that of norfloxacin and comparable to those of DR-3355 and ciprofloxacin.

Animals↗
PubMed1990

Comparative in vitro and in vivo activities of six new monofluoroquinolone and difluoroquinolone 3-carboxylic acids with a 7-azetidin ring substituent.

E-4502, E-4501, E-4500, E-4480, E-4474, and E-4441 are new monofluorinated or difluorinated quinolone agents that are chemically characterized by the presence of an azetidin ring, with different C'-3 substituents, at position 7 of the molecular structure. The MICs of the difluorinated compounds E-4501, E-4474, and E-4441 for 90% of isolates were 0.06 to 1, 0.06 to 1, and 0.12 to 1 microgram/ml, respectively, against gram-positive organisms (staphylococci, streptococci, and Enterococcus faecalis); 0.0015 to 0.12, 0.015 to 0.12, and 0.03 to 0.12 microgram/ml, respectively, against members of the family Enterobacteriaceae except Providencia spp.; and 1, 1, and 2 micrograms/ml, respectively, against Pseudomonas aeruginosa. E-4501, E-4474, and E-4441 inhibited all anaerobic bacteria at concentrations of 1, 2, and 4 micrograms/ml, respectively. Difluorinated compounds were significantly more active than the corresponding monofluorinated analogs E-4502, E-4500, and E-4480 against aerobic and facultatively anaerobic organisms, as well as against anaerobes. Considering monofluorinated and difluorinated compounds, activity in moderate ascending order was observed in quinolones containing an amine and a methyl group (E-4441 and E-4480), an amine group (E-4474 and E-4500), and a methylamine group (E-4501 and E-4502) in the C'-3 position of the azetidin ring. E-4501, E-4474, and E-4441 were more active than norfloxacin and DR-3355 [S-(-)-ofloxacin], had activities comparable to or slightly lower than that of ciprofloxacin against gram-negative bacteria, and were more active than all the reference quinolones against gram-positive organisms and anaerobes. E-4502 and E-4501, which were used to determine the effect of pH, were less active in acidic medium. In general, E-4502, E-4501, E-4500, E-4480, E-4474, and E-4441 activities were not affected or increased in medium containing serum but decreased in the presence of 10 mM Mg2+ or in human urine at pH 5.5. The protective effect of E-4501, E-4474, and E-4441 after oral administration against systemic infections with Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa in mice was greater than that of ciprofloxacin.

4-Quinolones↗
PubMed1989

Brown pigmentation in Serratia marcescens cultures associated with tyrosine metabolism.

Serratia marcescens produced a brown pigment when grown in minimal medium in the presence of tyrosine and high concentrations of copper(II) ion. The pigment was not related to the melanin pigments, but was similar to the pigment produced by autooxidation and polymerization of 3,4-dihydroxyphenylacetate, which is synthesized in S. marcescens from tyrosine through the 3,4-dihydroxyphenylacetate catabolic pathway. The enzymes of this pathway were induced under pigment production conditions; however, 3,4-dihydroxyphenylacetate 2,3-dioxygenase remained at low activity levels, permitting the accumulation and excretion of the substrate. Mutants unable to use tyrosine as a sole carbon and energy source were able to produce brown pigments only if the step blocked by the mutation was after the synthesis of 3,4-dihydroxyphenylacetate. The ability to produce brown pigments was common to all the S. marcescens strains tested.

Chemical Phenomena↗
PubMed1988

Characterization of B278, a phage different from Mu that also produces auxotrophic mutations in Escherichia coli K12.

Bacteriophage B278 has been characterized and compared with Mu, the only phage known to produce random mutations in E. coli. Although both phages are morphologically indistinguishable and have a similar host range, they clearly differ at both the protein and the DNA level. B278 apparently possesses a DNA protection mechanism that is different from the mom system described for Mu.

Bacteriophage mu↗
PubMed1988

Activity of E-3846, a new fluoroquinolone, in vitro and in experimental cystitis and pyelonephritis in rats.

The in vitro antibacterial activity of E-3846, a new fluoroquinolone carboxylic acid derivative with a pyrrol ring substituent at position 7, was evaluated in comparison with norfloxacin and ciprofloxacin. E-3846 was more active than the reference quinolones against Staphylococcus species, including methicillin-resistant strains. E-3846 was similar to ciprofloxacin and more active than norfloxacin against Streptococcus (Enterococcus) faecalis. In general, E-3846 was more active than norfloxacin against members of the family Enterobacteriaceae, but less active than ciprofloxacin. For Pseudomonas aeruginosa, the MICs giving 90% inhibition for E-3846, norfloxacin, and ciprofloxacin were 2, 1, and 0.25 micrograms/ml, respectively. The activity of E-3846 increased at acid pH; in contrast, acid pH caused a pronounced decrease in the activity of norfloxacin and ciprofloxacin. In vivo, E-3846 demonstrated excellent therapeutic efficacy in treating experimental S. faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa cystitis and pyelonephritis in rats.

Animals↗
PubMed1988

Induction of Yellow Pigmentation in Serratia marcescens.

The appearance of yellow pigmentation in nonpigmented strains of Serratia sp. has been demonstrated to be due to the production of a muconic acid, 2-hydroxy-5-carboxymethylmuconic acid semialdehyde. The 3,4-dihydroxyphenylacetate 2,3-dioxygenase responsible for the synthesis of this muconic acid was induced in all strains tested. Another muconic acid, the beta-cis-cis-carboxymuconic acid, could also be synthesized from 3,4-dihydroxybenzoate, but this product was not colored. Mutants that were unable to grow on tyrosine and produced yellow pigment were isolated from nonpigmented strains. These mutants had properties similar to those of the yellow-pigmented strains. The ability to produce pigment may be more widespread among Serratia marcescens strains than is currently known.

Journal Article↗
PubMed1987

Isolation from urine of two Serratia marcescens strains excreting a diffusible yellow pigment.

Two bacterial strains excreting a yellow pigment were isolated from human urine and identified as Serratia marcescens. The pigment was produced in the late exponential and early stationary phases of growth. Minimal media supplemented with tyrosine, phenylalanine, 3,4-dihydroxyphenylacetate or tryptophan, as well as complex media, induced pigment production. UV-visible spectra of the extracted pigment had peaks characteristic of 2-hydroxy-5-carboxymethylmuconate semialdehyde, produced from meta-cleavage of 3,4-dihydroxyphenylacetate by the enzyme 3,4-dihydroxyphenylacetate 2,3-dioxygenase (EC 1.13.11.15). This enzyme was active when the bacteria were grown under conditions promoting pigment production. The kinetics and factors affecting pigment production are also reported.

Dioxygenases↗