Purification and characterization of a biosurfactant produced by Bacillus subtilis in cashew apple juice and its application in the remediation of oil-contaminated soil.

The ability of some microorganisms to use clarified cashew apple juice as carbon and energy source for biosurfactant production was assessed under strict controlled conditions. Twelve strains of Bacillus were isolated and evaluated regarding their biosurfactant production capabilities. The biosurfactant obtained with these selected strains showed the capacity of decreasing the surface tension of water from 72.0 to 31.8 mN.m-1 and the interfacial tension of n-hexadecane to 27.2 mN.m-1, with a critical micelle concentration of 12.5 mg.L-1. Not only did the biosurfactant present excellent stability to pH, temperature and salinity, it also showed emulsifying properties in different hydrocarbons. The behavior of the phase diagrams showed the potential of the produced biosurfactant to obtain relatively-stable emulsions for up to 96 h, which allows for its application in several areas. The semi-purified biosurfactant did not show toxicity against Lactuca sativa (lettuce) or Artemia salina (microcrustacean), presenting an LC50 of 612.27 µ mL-1. The surfactant was characterized as being a cyclic lipopeptide with molecular structure similar to that of surfactin. Furthermore, through the employment of the surfactant produced, the remediation effect in oil-contaminated soil could be significantly improved.

Real-time visualization of MMP-13 promoter activity in transgenic mice.

Cutaneous wound repair involves extracellular matrix degradation, cell migration, matrix resynthesis and tissue remodeling. In the rodent, transcriptional regulation of collagenase-3 (MMP-13) most likely plays a role in these processes. Therefore, we isolated and characterized a 1.76-kb 5'-flanking region of the mouse MMP-13 gene. Assay of promoter activity by transient transfection of HT1080 cells and primary mouse skin fibroblasts allowed identification of several functional regions of the 5'-flanking DNA. Expression of luciferase reporter constructs in these cells was induced by phorbol myristate acetate (PMA), but not by transforming growth factor-beta(2) (TGF-beta(2)). To study the regulation of MMP-13 in cutaneous wound healing, we generated transgenic mouse lines harboring the firefly luciferase reporter gene under control of a 660-bp mouse MMP-13 promoter which showed maximal response. MMP-13 mRNA levels in transgenic lung fibroblasts increased 1.5-2.6-fold after PMA challenge. MMP-13 promoter activity in wounds was visualized and quantified in vivo as luciferase bioluminescence. MMP-13 expression was present at day 1 and maximal at day 18 post-wounding. Luciferase activity progressed from the wound margin towards the center of the wound. In situ hybridization showed the same spatial and temporal patterns for the luciferase and endogenous MMP-13 mRNA. Both signals localized predominantly to dermal fibroblasts at the wound periphery but not to granulation tissue or to keratinocytes. These results suggested that MMP-13 participated in the wound healing of acute wounds, and it was a significant factor in long-term remodeling of wound connective tissue in rodent skin.

Cannabis use is associated with increased CCL11 plasma levels in young healthy volunteers.

Cannabis is a widely used recreational drug. Its effect on human health and psychosis remains controversial. In this study, we aimed to explore the possibility that cannabis use influenced CCL11 plasma levels. Increased CCL11 chemokine has been reported in schizophrenia and cannabis is a known trigger of schizophrenia. Additionally, plasma levels of the chemokine CCL11 have recently been shown to increase with age and with cognitive deficits and hippocampal neurogenesis. For this study, a total of 87 healthy volunteers (68% men, age range 18-35 years) completed the Cannabis Experience Questionnaire that included information on sociodemographic and morphometric data and provided a blood sample for CCL11 measurement. 'Current users' of cannabis (n=18) had significantly higher CCL11 plasma levels compared to 'past users' (n=33) and 'never users' (n=36) [F(3,84)=3.649; p=0.030]. The latter two groups had similar CCL11 levels. Higher CCL11 plasma levels could not be attributed to gender, age, body mass index, physical activity or use of other legal/illegal drugs. These results suggest that cannabis use increases CCL11 plasma levels and the effects are reversible when cannabis use ceases.

Kinetic study of biosurfactant production by Bacillus subtilis LAMI005 grown in clarified cashew apple juice.

In this work a low cost medium for the production of a biosurfactant by Bacillus subtilis LAMI005 and the kinetics of surfactin production considering the effect of initial substrate concentration were investigated. First, cashew apple juice supplementation for optimal production of biosurfactant by B. subtilis LAMI005 was studied. The medium formulated with clarified cashew apple juice and distilled water, supplemented with 1.0 g/L of (NH(4))(2)SO(4), proved to be the best among the nutrients evaluated. The crude biosurfactant had the ability to decrease the surface tension of water to 30 dyne/cm, with a critical micelle concentration (CMC) of 63.0 mg/L. Emulsification experiments indicated that this biosurfactant effectively emulsified kerosene (IE(24)=67%) and soybean oil (IE(24)=64%). Furthermore, the emulsion stability was always very high. It was shown by biochemical analysis, IR spectra, that there is no qualitative differences in the composition of the crude biosurfactant from a standard sample of surfactin from B. subtilis.

Clarified cashew apple juice as alternative raw material for biosurfactant production by Bacillus subtilis in a batch bioreactor.

Clarified cashew apple juice was evaluated as carbon source for surfactin production by Bacillus subtilis LAMI005 isolated from the tank of chlorination at the Wastewater Treatment Plant on Campus do Pici (WWTP-PICI) in the Federal University of Ceará, Brazil. The highest surfactin concentration using clarified cashew apple juice (CCAJ) supplemented with mineral medium (MM-CCAJ) was 123 mg/L, achieved after 48 h of fermentation. Almost 2-fold less than the amount produced using mineral medium supplemented with 10 g/L of glucose and 8.7 g/L of fructose (MM-GF). However, critical micelle concentration of the biosurfactants produced using MM-CCAJ was 2.5-fold lower than the one produced using MM-GF, which indicates it is a more efficient biosurfactant. Surface tension decreased from 38.50 +/- 0.0 to 29.00 +/- 0.0 dyne/cm when B. subtilis was grown on MM-CCAJ media (24.68% of reduction on surface tension) and remained constant up to 72 h. Emulsification index was 51.15 and 66.70% using soybean oil and kerosene, respectively. Surfactin produced in MM-CCAJ showed an emulsifying activity of, respectively, 1.75 and 2.3 U when n-hexadecane or soybean oil was tested. However, when mineral medium supplemented with 10 g/L of glucose (MM-G) was used an emulsifying activity of 2.0 and 1.75 U, with n-hexadecane and soybean oil, respectively, was obtained. These results indicate that it is feasible to produce surfactin from CCAJ, a renewable and low-cost carbon source.