Evaluation of genetic divergence among clones of conilon coffee after scheduled cycle pruning.

Coffea canephora genotypes from the breeding program of Instituto Capixaba de Pesquisa e Extensão Rural were evaluated, and genetic diversity was estimated with the aim of future improvement strategies. From an initial group of 55 genotypes, 18 from the region of Castelo, ES, were selected, and three clones of the cultivars "Vitória" and "robusta tropical." Upon completion of the scheduled cycle pruning, 17 morphoagronomic traits were measured in the 22 genotypes selected. The principal components method was used to evaluate the contributions relative to the traits. The genetic dissimilarity matrix was obtained through Mahalanobis generalized distance, and genotypes were grouped using the hierarchical method based on the mean of the distances. The most promising clones of Avaliação Castelo were AC02, AC03, AC12, AC13, AC22, AC24, AC26, AC27, AC28, AC29, AC30, AC35, AC36, AC37, AC39, AC40, AC43, and AC46. These methods detected high genetic variability, grouping, by similarity, the genotypes in five groups. The trait that contributed the least to genetic divergence was the number of leaves in plagiotropic branches; however, this was not eliminated, because discarding it altered the groups. There are superior genotypes with potential for use in the next stages of the breeding program, aimed at both the composition of clonal variety and hybridizations.

Entanglement and the nonlinear elastic behavior of forests of coiled carbon nanotubes.

Helical or coiled nanostructures have been objects of intense experimental and theoretical studies due to their special electronic and mechanical properties. Recently, it was experimentally reported that the dynamical response of a foamlike forest of coiled carbon nanotubes under mechanical impact exhibits a nonlinear, non-Hertzian behavior, with no trace of plastic deformation. The physical origin of this unusual behavior is not yet fully understood. In this Letter, based on analytical models, we show that the entanglement among neighboring coils in the superior part of the forest surface must be taken into account for a full description of the strongly nonlinear behavior of the impact response of a drop ball onto a forest of coiled carbon nanotubes.

Effect of subinhibitory concentration of piperacillin/tazobactam on Pseudomonas aeruginosa.

Subinhibitory concentrations (sub-MICs) of antibiotics, although not able to kill bacteria, can modify their physico-chemical characteristics and the architecture of their outermost surface and may interfere with some bacterial functions. This study investigated the ability of sub-MIC piperacillin/tazobactam (P/T) to interfere with the bacterial virulence parameters of adhesiveness, cell-surface hydrophobicity, motility, biofilm formation and sensitivity to oxidative stress. Antimicrobial activity against five Pseudomonas aeruginosa clinical isolates, representative of clonal lineages of 96 strains of nosocomial origin, and six control strains (ATCC 27853, PAO1, AK1, MT1562, PT623, PAO1algC) was evaluated in vitro using the NCCLS microdilution method. The effects of sub-MIC on bacterial adhesion and biofilm formation were studied using a modified microtitre plate assay. The relative cell-surface hydrophobicity of P. aeruginosa strains was determined by measuring their ability to adhere to n-hexadecane. P. aeruginosa that had been exposed overnight to P/T and incubated with P/T in the plate were also screened for their ability to swim using flagella and to twitch and for their sensitivity to oxidative stress. The results obtained showed that the impact of sub-MIC P/T on bacterial characteristics was different for the various strains of P. aeruginosa. There was a change in bacterial morphology and hydrophobicity that could explain a significant decrease in adhesion values in all clinical isolates and controls tested, a decrease in biofilm formation, a significant increase in sensitivity to oxidative stress, a significant decrease in flagellum-mediated swimming and a decrease in type IV fimbriae-mediated twitching. The results obtained indicate that sub-MIC P/T interferes with the pathogenic potential of P. aeruginosa.

Near equilibrium dynamics of nonhomogeneous Kirchhoff filaments in viscous media.

We study the near equilibrium dynamics of nonhomogeneous elastic filaments in viscous media using the Kirchhoff model of rods. Viscosity is incorporated in the model as an external force, which we approximate by the resistance felt by an infinite cylinder immersed in a slowly moving fluid. We use the recently developed method of Goriely and Tabor [Phys. Rev. Lett. 77, 3537 (1996); Physica D 105, 20 (1997); 105, 45 (1997)] to study the dynamics in the vicinity of the simplest equilibrium solution for a closed rod with nonhomogeneous distribution of mass, namely, the planar ring configuration. We show that small variations of the mass density along the rod are sufficient to couple the symmetric modes of the homogeneous rod problem, producing asymmetric deformations that modify substantially the dynamical coiling, even at quite low Reynolds number. The higher-density segments of the rod tend to become more rigid and less coiled. We comment on possible applications to DNA.

Antifungal activity of local anesthetics against Candida species.

OBJECTIVE: To evaluate the activity of benzydamine, lidocaine, and bupivacaine, three drugs with local anesthetic activity, against Candida albicans and non-albicans strains and to clarify their mechanism of activity. METHODS: The minimal inhibitory concentration (MIC) was determined for 20 Candida strains (18 clinical isolates and two American Type Culture Collection strains). The fungistatic activity was studied with the fluorescent probe FUN-1 and observation under epifluorescence microscopy and flow cytometry. The fungicidal activity of the three drugs was assayed by viability counts. Membrane alterations induced in the yeast cells were evaluated by staining with propidium iodide, by quantitation of intracellular K+ leakage and by transmission electron microscopy of intact yeast cells and prepared spheroplasts. RESULTS: The MIC ranged from 12.5-50.0 microg/mL, 5.0-40.0 mg/mL, and 2.5-10.0 mg/mL for benzydamine, lidocaine, and bupivacaine, respectively. The inhibitory activity of these concentrations could be detected with the fluorescent probe FUN-1 after incubation for 60 minutes. A very fast fungicidal activity was shown by 0.2, 50, and 30 mg/mL of benzydamine, lidocaine, and bupivacaine, respectively. CONCLUSIONS: At lower concentrations, the tested drugs have a fungistatic activity, due to yeast metabolic impairment, while at higher concentrations they are fungicidal, due to direct damage to the cytoplasmic membrane.

In vitro effect of fibrinogen on Candida albicans germ tube formation.

Pseudohyphae formation by Candida albicans blastoconidia, as seen in vaginal smears, is a phenotypical change commonly assumed to mean fungal invasiveness, i.e. not mere colonization. C. albicans forms germ tubes in vitro in the presence of serum. In our search for inhibitory components of germ tube formation, we decided to study fibrinogen. The inhibition of germ tube formation by clinical isolates of C. albicans was evaluated in the presence of serial concentrations of fraction I, type IV and fraction I, type Is of fibrinogen from bovine plasma. Fibrinogen showed a dose-dependent, pH-independent inhibitory effect on the germ tube formation by C. albicans.

Germ tube formation changes surface hydrophobicity of Candida cells.

Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane), 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of germ tube formation on adhesion were studied. C. albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ tube formation was associated with a significant rise in cell surface hydrophobicity.

Is the lack of concurrence of bacterial vaginosis and vaginal candidosis explained by the presence of bacterial amines?

OBJECTIVE AND STUDY DESIGN: We report for the first time an inhibitory effect on cell division and germ tube formation by Candida albicans and strains of other Candida species by putrescine and cadaverine. RESULTS: Both bacterial amines showed a dose-dependent inhibition of germ tube formation by C albicans, as well as budding (inhibition of cell division) of strains of other Candida species (ie, C glabrata, C krusei, and C tropicalis). CONCLUSIONS: We hypothesize that the presence of these and possibly other bacterial amines produced by anaerobes in the vaginal flora and seen in bacterial vaginosis, as in the healthy gut, may explain why candidosis is rarely seen in these instances.

In vitro effect of local anesthetics on candida albicans germ tube formation.

OBJECTIVE: This study was planned to clarify the in vitro effect of lidocaine and bupivacaine on germ tube formation by Candida albicans isolates from cases of clinical vaginal candidiasis. METHODS: Fourteen C. albicans strains (clinical vaginal isolates) were grown on Sabouraud agar for 24 h at 37 and tested as follows: 100 microl of a yeast suspension [10(5) colony forming units (CFU)/ml of phosphate buffered saline (PBS)] was added to 500 microl of fresh human serum with lidocaine or bupivacaine (pure salts) in serial concentrations. The test was run in duplicate. Controls were prepared for each strain. After 4 h of incubation at 37, samples were taken from each vial and 200 yeasts were counted in a counting chamber. The pH of each suspension was measured. RESULTS: The results are given as the mean of the 2 readings and are expressed as the percentage of blastoconidia with germ tubes/total blastoconidia. CONCLUSIONS: Our experiments show that both lidocaine and bupivacaine have a dose-dependent inhibitory effect, pH-independent, on germ tube formation by C. albicans and that both drugs seem to be promising in the treatment of genital candidiasis due to the combination of anesthetic and antifungal properties.

Evaluating the concentration of a Candida albicans suspension.

OBJECTIVE: The objective of this study was to develop a reproducible method of establishing the concentration of yeast cells per milliliter of solution. METHODS: Three methods of determining the number of yeast cells in solution were compared: Neubauer's counting chamber, spectrophotometry, and nephelometry. RESULTS: All three methods were comparable and reproducible. The following formulas were highly effective in determining the number of yeast cells in solution: chamber (x 10(3)/ ml) 64.3 + 8,206 x spectrophotometry (absorbance); and chamber (x 10(3) /ml) -0.2 + 64 x nephelometry (volt). CONCLUSIONS: Utilization of spectrophotometry or nephelometry and the appropriate formula allow for the precise determination, which is easily reproducible, of the concentration of yeast cells in solution. This will facilitate experimentation involving precise inocula or requirement for specific concentrations of yeast cells for various experiments.

Prevalence of Candida albicans in vaginal fluid of asymptomatic Portuguese women.

Candida albicans is by far the most frequent agent of genital candidosis. We studied the prevalence of C albicans in normal asymptomatic women attending primary health care centers throughout Portugal. The overall prevalence of C albicans in the vaginal fluid of 1,004 women studied was 10.4%. Interestingly, the prevalence rates were lower (6.8%) in women taking combination oral contraceptives and higher (13.0%) in those using intrauterine devices.

PIP: In Portugal, a physician from a rural primary health care center and one from an urban primary health care center from each of 18 districts took vaginal swabs from 1004 14-to-80-year-old asymptomatic women to send to a laboratory at the University of Porto School of Medicine, where staff examined 1 week old cultures for yeast cells. This vaginal fluid collection was part of a research project of the Portuguese Group for the Study of Pelvic Inflammatory Disease and Sexually Transmitted Diseases based at the University's Departments of Microbiology, Biostatistics, and Hygiene and Social Medicine. They confirmed 104 positive Candida albicans cultures (10.4%). C. albicans prevalence was considerably higher in women using an IUD than it was in women using an oral contraceptive (13% vs. 6.8%; p = .03). Prevalence was also greater among women whose vaginal fluid had a macroscopic appearance suspicious of candidosis than among those whose vaginal fluid did not have such an appearance (p .05). Pregnant women had the highest colonization rates. The various means for daily genital care (i.e., soap vs. antiseptics) did not influence C. albicans prevalence. These results were probably representative of the female population in Portugal.

Essential hypertension: the relationship of psychological factors to the severity of hypertension.

165 hypertensive patients attending one general practice in Portugal were found to report significantly higher scores on measures of neuroticism, anxiety, depression and general psychological distress than 152 normotensive patients at the same practice. Hypertensive patients with evidence of organ damage exhibited significantly higher depression scores than those without such damage. These differences between normotensives and hypertensives, and between hypertensive with and without organ damage are discussed and previous research in this area is reviewed.