Environmental fate, toxicity, characteristics and potential applications of novel bioemulsifiers produced by Variovorax paradoxus 7bCT5.

The aims of this work were the characterisation and the evaluation of potential environmental applications of the bioemulsifiers produced by Variovorax paradoxus 7bCT5. V. paradoxus 7bCT5 produces a mixture of high molecular weight polysaccharides. The extracellular bioemulsifiers were able to produce a thick stable oil/water emulsion and maintained the emulsification activity after boiling and at low temperatures. Environmental behavior and impact of bioemulsifiers release were assessed by evaluating biodegradability, toxicity and soil sorption. Respirometric tests showed that moderate biodegradability occurred by soil bacterial inoculum. Furthermore, the produced compounds did not show any toxic properties through different ecotoxicological tests. The K(d) values ranged from 1.3 to 7.3 L/kg indicating a high sorption affinity of the bioemulsifier molecules to soil particles. The soil sorption affinity likely affected the bioemulsifier ability to remove hydrocarbons from contaminated soils. In fact, V. paradoxus 7bCT5 bioemulsifiers significantly increased the removal of crude-oil from sandy soil compared to water.

Long-term evaluation of glucose homeostasis in a cohort of HAART-treated HIV-infected children: a longitudinal, observational cohort study.

BACKGROUND AND OBJECTIVES: Few and mainly cross-sectional studies of glucose homeostasis are available in HIV-infected children treated with highly active antiretroviral therapy (HAART). The aim of the present study was to describe a 4-year course of glucose homeostasis in a cohort of HAART-treated children and adolescents, using glucose and insulin levels during an oral glucose tolerance test (OGTT) as outcome measures. In addition, we investigated possible risk factors, both related and unrelated to antiretroviral therapy, associated with insulin resistance. METHODS: We assessed glucose metabolism yearly for 4 consecutive years in 37 HIV-infected children receiving a protease inhibitor (PI)-based HAART regimen containing lamivudine/stavudine plus indinavir or ritonavir or nelfinavir or a non-nucleoside reverse transcriptase inhibitor (NNRTI)-based HAART regimen containing lamivudine/tenofovir/efavirenz. Generalized estimating equations were used to evaluate the relationship between the loge-transformed area under the serum concentration-time curve (AUC) of insulin during OGTT and antiretroviral therapy, controlling for time, sex, baseline age, puberty, body mass index and CD4+ T cells percentage. RESULTS: Ritonavir-unboosted PI-based HAART regimens were administered to most children at baseline; however, their use decreased during follow-up in favour of an NNRTI-based regimen. The nelfinavir/lamivudine/stavudine (regression coefficient=-0.69, p<0.05) and efavirenz/lamivudine/tenofovir (regression coefficient=-0.93, p<0.05) regimens, but not the ritonavir/lamivudine/stavudine regimen, were negatively associated with loge-transformed insulin AUC compared with indinavir/lamivudine/stavudine. Puberty was positively associated with loge-transformed insulin AUC. CONCLUSIONS: This 4-year prospective study of HAART-treated HIV-infected children shows that: (i) the nelfinavir/lamivudine/stavudine and the efavirenz/lamivudine/tenofovir regimens but not the ritonavir/lamivudine/stavudine regimen were associated with higher insulin sensivity, i.e. lower insulin AUC, compared with indinavir/lamivudine/stavudine; (ii) the treatment switched substantially in favour of NNRTI from the third year on and this change was associated with an improvement in insulin sensitivity compared with the previous HAART-based regimens; and (iii) puberty is a primary determinant of insulin sensitivity.