Fatty acid composition of vegetable oil blend and in vitro effects of pharmacotherapeutical skin care applications.

Vegetable oils have been used for a plethora of health benefits by their incorporation in foods, cosmetics, and pharmaceutical products, especially those intended for skin care. This study aimed to investigate the cutaneous benefits of a vegetable oil blend (VOB) formulation and its fatty acid composition. The anti-inflammatory activity was studied in macrophages of RAW 264.7 cells by investigating the release of nitric oxide (NO), superoxide anion generation (O2-), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6). ABTS cation radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and NO free radical scavenging assays were used to evaluate the antioxidant activity. VOB was tested for its ability to stimulate fibroblast proliferation and migration using the scratch assay, and antibacterial activity by the microdilution test. The fatty acid profile of a freshly prepared VOB formulation was determined by gas chromatography before and after accelerated stability testing. Chemical composition of VOB revealed the presence of oleic acid (C18:1n-9; 63.3%), linoleic acid (C18:2n-6; 4.7%), and linolenic acid (C18:3n-6; 5.1%) as major mono- and polyunsaturated fatty acids. No changes in the organoleptic characteristics and fatty acid composition were observed after the accelerated stability test. VOB 100 µg/mL reduced the healing time by increasing the total number of cells in the wounded area by 43.0±5.1% compared to the negative control group. VOB also suppressed the pro-inflammatory TNF-α and IL-6 cytokines, and NO and O2- production in lipopolysaccharide-stimulated macrophage cells. In conclusion, the VOB formulation contributed to the improvement of current therapeutic strategies for cutaneous applications in skin care.

Fatty acid composition of vegetable oil blend and in vitro effects of pharmacotherapeutical skin care applications

Vegetable oils have been used for a plethora of health benefits by their incorporation in foods, cosmetics, and pharmaceutical products, especially those intended for skin care. This study aimed to investigate the cutaneous benefits of a vegetable oil blend (VOB) formulation and its fatty acid composition. The anti-inflammatory activity was studied in macrophages of RAW 264.7 cells by investigating the release of nitric oxide (NO), superoxide anion generation (O2-), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6). ABTS cation radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and NO free radical scavenging assays were used to evaluate the antioxidant activity. VOB was tested for its ability to stimulate fibroblast proliferation and migration using the scratch assay, and antibacterial activity by the microdilution test. The fatty acid profile of a freshly prepared VOB formulation was determined by gas chromatography before and after accelerated stability testing. Chemical composition of VOB revealed the presence of oleic acid (C18:1n-9; 63.3%), linoleic acid (C18:2n-6; 4.7%), and linolenic acid (C18:3n-6; 5.1%) as major mono- and polyunsaturated fatty acids. No changes in the organoleptic characteristics and fatty acid composition were observed after the accelerated stability test. VOB 100 µg/mL reduced the healing time by increasing the total number of cells in the wounded area by 43.0±5.1% compared to the negative control group. VOB also suppressed the pro-inflammatory TNF-α and IL-6 cytokines, and NO and O2- production in lipopolysaccharide-stimulated macrophage cells. In conclusion, the VOB formulation contributed to the improvement of current therapeutic strategies for cutaneous applications in skin care.

Oral mucosa as a source of Mycobacterium leprae infection and transmission, and implications of bacterial DNA detection and the immunological status.

Leprosy is an important health problem in Brazil despite extensive use of multidrug therapy. The nasal mucosa is the preferential site of entry and exit of Mycobacterium leprae, and although lesions have been found in the oral mucosa, its potential involvement in the transmission of leprosy bacilli has never been investigated. We investigated the presence of the M. leprae DNA in buccal swabs of leprosy patients (334) and household contacts (1288) through polymerase chain reaction (PCR), and correlated this with clinical and laboratorial evaluations. The overall positivity for patients and contacts was 18.26% and 6.83%, respectively. Subclinical infection among contacts was considered when PCR and anti-PGL-1 ELISA presented positive results. This study provides evidence that the oral mucosa may be a secondary site of M. leprae transmission and infection, and contacts with bacillary DNA may be actively involved in transmission. We have also shown that bacilli DNA is more frequently found in the oral mucosa of PB patients. Our findings have great epidemiological relevance and indicate an additional strategy for leprosy control programmes and dental clinics.

Production of heterologous protein by Methylobacterium extorquens in high cell density fermentation.

The green fluorescent protein (GFP) was used as a model protein to study the recombinant protein production by the strain Methylobacterium extorquens ATCC 55366. Scale-up from shake flasks to 20 l fed-batch fermentation was achieved using methanol as a sole carbon and energy source and a completely minimal culture medium. Two different expression vectors were used to express GFP. Clone PCM-GFP containing the vector pCM110 with native promoter of the methanol dehydrogenase PmxaF produced approximately 100-fold more GFP than the clone PRK-GFP containing the vector pRK310 with the heterogeneous promoter Plac. Several fed-batch fermentations with and without selective pressure (tetracycline) were run in a 20 l stirred tank fermenter using the two different clones of M. extorquens. The methanol concentration was monitored with an on-line semiconductor gas sensor in the culture broth. It was maintained at a non-toxic level of 1.4 g l(-1) with an adaptative control which regulates the methanol feed rate. The same growth profile was achieved in all fermentations. The maximum growth rate (micro(max)) was 0.18 h(-1) with an overall yield (Y(X/S)) of 0.3 g g(-1) methanol. With this high cell density fermentation process, we obtained high levels (up to 4 g l(-1)) of GFP with the clone PCM-GFP. The maximum specific GFP production (Y(GFP/X)) with this clone was 80 mg g(-1) representing approximately 16% of the total cell protein. Additional feeding of pure oxygen to the fermenter permitted a longer phase of exponential growth but had no effect on the total yields of biomass and GFP. The specific GFP production of clone PCM-GFP remained unaffected in the presence or absence of selective pressure (tetracycline), within the initial 50 h of the fermentation culture. These results suggest that M. extorquens ATCC 55366 could be an interesting candidate for overexpression of recombinant proteins.

Influence of Bacillus subtilis cell walls and EDTA on calcite dissolution rates and crystal surface features.

This study investigates the influence of EDTA and the Gram-positive cell walls of Bacillus subtilis on the dissolution rates and development of morphological features on the calcite [1014] surface. The calcite dissolution rates are compared at equivalent saturation indicies (SI) and relative to its dissolution behavior in distilled water (DW). Results indicate that the presence of metabolically inactive B. subtilis does not affect the dissolution rates significantly. Apparent increases in dissolution rates in the presence of the dead bacterial cells can be accounted for by a decrease of the saturation state of the solution with respect to calcite resulting from bonding of dissolved Ca2+ by functional groups on the cell walls. In contrast, the addition of EDTA to the experimental solutions results in a distinct increase in dissolution rates relative to those measured in DW and the bacterial cell suspensions. These results are partly explained by the 6.5-8 orders of magnitude greater stability of the Ca-EDTA complex relative to the Ca-B. subtilis complexes as well as its free diffusion to and direct attack of the calcite surface. Atomic force microscopy images of the [1014] surface of calcite crystals exposed to our experimental solutions reveal the development of dissolution pits with different morphologies according to the nature and concentration of the ligand. Highly anisotropic dissolution pits develop in the early stages of the dissolution reaction at low B. subtilis concentrations (0.004 mM functional group sites) and in DW. In contrast, at high functional group concentrations (4.0 mM EDTA or equivalent B. subtilis functional group sites), dissolution pits are more isotropic. These results suggest that the mechanism of calcite dissolution is modified by the presence of high concentrations of organic ligands. Since all the pits that developed on the calcite surfaces display some degree of anisotropy and dissolution rates are strongly SI dependent, the rate-limiting step is most likely a surface reaction for all systems investigated in this study. Results of this study emphasize the importance of solution chemistry and speciation in determining calcite reaction rates and give a more accurate and thermodynamically sound representation of dead bacterial cell wall-mineral interactions. In studies of natural aquatic systems, the presence of organic ligands is most often ignored in speciation calculations. This study clearly demonstrates that this oversight may lead to an overestimation of the saturation state of the solutions with respect to calcite and thermodynamic inconsistencies.

Production of green fluorescent protein by the methylotrophic bacterium methylobacterium extorquens.

The production of green fluorescent protein (GFP) in Methylobacterium extorquens was studied by creating four different constructs using pJB3KmD, pRK310 and pVK101 vectors, as well as pLac and soluble methane monooxygenase (sMMO) promoters. Plasmids were introduced into the cells by electroporation. Expression of GFP by selected clones was evaluated by growing cells in complex or defined media. The use of pRK310 as an expression vector containing the lacZ promoter resulted in a 100-fold increase of GFP production when compared to cells containing the pLac-GFP-pJB3KmD construct. Higher production of GFP was observed also in cells containing pLac-GFP-pRK310 and pmmoX-GFP-pVK101 constructs. While the transcriptional regulation of the smmo gene in Methylosinus trichosporium OB3b is known to be copper-dependent, expression of GFP by M. extorquens clones harboring pmmoX-promoters was not strongly controlled by the presence of copper in the medium. The production of GFP was generally constant throughout the growth of M. extorquens carrying the pLac-GFP-pRK310 construct. GFP yields varied between 850 and 1000 microg of GFP g biomass(-1). However, the yield of GFP in cells carrying pmmoX-GFP-pVK101 was somewhat reduced after the mid-exponential phase of growth.

Medical students at risk of nosocomial transmission of Mycobacterium tuberculosis.

SETTING: University and teaching hospital in Rio de Janeiro, Brazil, a city with a high prevalence of tuberculosis (TB). OBJECTIVE: To determine whether medical students are at increased risk of nosocomial transmission of Mycobacterium tuberculosis relative to other university students. DESIGN: A cross-sectional study of medical and chemical engineering students in different levels of their training programmes. Information about socio-demographic characteristics, BCG vaccination history, and potential exposures to TB were obtained using a standardised questionnaire. Tuberculin skin testing (TST) was used to determine the prevalence of infection with TB. RESULTS: Medical students have an increasing prevalence of TST positivity as they advance in their training programme to increasing levels of study (4.6%, 7.8%, 16.2%, respectively, P < 0.001), but chemical engineering students do not (4.2%, 4.3%, 4.4%, respectively, P = 0.913). The risks are greatest during the years of clinical training, when medical students have increased contact with patients. CONCLUSIONS: Medical students in this setting may be at increased risk of M. tuberculosis infection, relative to chemical engineering students. A programme of routine tuberculin skin testing is needed, combined with interventions to reduce the risk of nosocomial transmission in the workplace.

Assessment of interference in biosorption of a heavy metal.

Nonliving biomass of Sargassum, a brown marine alga, is capable of binding more than 10% of its dry weight in toxic cadmium ions. Although ubiquitous iron interferes with Cd uptake, only approximately 4.5% of it is sequestered (biomass dry weight). Biosorption of both metals at ph 4.5 could be described by Langmuir-type isotherms with b, the affinity-related coefficient (Cd: b = 0.015; Fe: b = 0.027). The interference of Fe with Cd uptake, and vice versa, was assessed by deriving three-dimensional equilibrium two-metal sorption isotherm surfaces, smoothed and "cut" to reveal the inhibition effect of Fe on biosorption of Cd: at the equilibrium concentration Cf[Cd] = 1.5 mM, the presence of Fe at 1.5 mM equilibrium concentration suppressed the Cd uptake to only 76% of the original value. For 50% Cd uptake reduction, a very high equilibrium Fe presence of 4.5 mM was required. The Cd presence affected the uptake of Fe very strongly. To obtain equal values of uptake for each metal in the biosorbent, the ratio of equilibrium concentrations of 0.42 Cd to 1 Fe is necessary in the liquid phase. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 344-350, 1997.

Cyanide degradation by an Escherichia coli strain.

Chemical formation of a glucose-cyanide complex was necessary for metabolic degradation of cyanide at concentrations up to 50.0 mg/L by a strain of Escherichia coli isolated from gold extraction circuit liquids. Ammonia accumulating during the culture log phase as the sole nitrogen by-product was further utilized for bacterial growth. Washed (intact) cells, harvested at different periods of bacterial growth on cyanide, consumed oxygen in presence of cyanide. These findings suggest that metabolism of cyanide involved a dioxygenase enzyme that converted cyanide directly to ammonia, without the formation of cyanate.

Utilization of ammonia, generated from abiotic cyanide degradation, by Rhodotorula rubra.

The viability of the yeast Rhodotorula rubra, isolated from liquid samples of gold-mine effluents, was not affected by the presence of 11.52 mM cyanide. The yeast was able to utilize ammonia, generated from abiotic cyanide degradation in the presence of reducing sugars, in aerobic culture at pH 9.0. These physiological characteristics encourage studies with mixed cultures of cyanide-degrading organisms, using this yeast as an assimilator of ammonia.