Use of response surface design in the optimization of starter cultures for enhanced rhamnolipid production by Pseudomonas nitroreducens

The development and management of an inoculum through various stages has a definite effect on subsequent performance and economics of a microbial process. To achieve this, application of response surface modeling in the optimization of the primary and secondary inoculum build-up of Pseudomonas nitroreducens for enhanced rhamnolipid production was presented in this study. This involved systematic studies to understand the individual, cumulative and mutual interactive effects of the two parameters, inoculum age and size on rhamnolipid production. The optimal combination of factors was as follows: primary inoculum age = 61 h, primary inoculum size = 1% (v/v), secondary inoculum age = 28 h and secondary inoculum size = 20% (v/v). The model predicted a maximum rhamnolipid yield of 7.944 g/L. This was as a result of strong interaction between secondary inoculum age and size. The subsequent experiments with the optimized conditions yielded 6.97 g/L of rhamnolipid, which is very consistent with the prediction made by the model used.Keywords: Biosurfactants, inoculum age, inoculum size, Pseudomonas nitroreducens, response surface design, rhamnolipidAfrican Journal of Biotechnology Vol. 12(19), pp. 2611-261

Efficiency of first-trimester uterine artery Doppler, A-disintegrin and metalloprotease 12, pregnancy-associated plasma protein A, and maternal characteristics in the prediction of preeclampsia

OBJECTIVE: To estimate the efficiency of first-trimester uterine artery Doppler, A-disintegrin and metalloprotease 12 (ADAM12), pregnancy-associated plasma protein A (PAPP-A) and maternal characteristics in the prediction of pre-eclampsia. METHODS: This is a prospective cohort study of patients presenting for first-trimester aneuploidy screening between 11-14 weeks’ gestation. Maternal serum ADAM12 and PAPP-A levels were measured by immunoassay, and mean uterine artery Doppler pulsatility indices (PI) were calculated. Outcomes of interest included pre-eclampsia, early pre-eclampsia, defined as requiring delivery at <34 weeks’ gestation, and gestational hypertension. Logistic regression analysis was used to model the prediction of pre-eclampsia using ADAM12 multiples of the median (MoM), PAPP-A MoM, and uterine artery Doppler PI MoM, either individually or in combination. Sensitivity, specificity, and area under the receiver-operating characteristic curves (AUC) were used to compare the screening efficiency of the models using non-parametric U-statistics. RESULTS: Of 578 patients with complete outcome data, there were 54 (9.3%) cases of preeclampsia and 13 (2.2%) cases of early pre-eclampsia. Median ADAM12 levels were significantly lower in patients who developed pre-eclampsia compared to those who did not. (0.81 v. 1.01 MoMs; p<0.04) For a fixed false positive rate (FPR) of 10%, ADAM12, PAPP-A, and uterine artery Doppler in combination with maternal characteristics identified 50%, 48%, and 52% of patients who developed pre-eclampsia, respectively. Combining these first-trimester parameters did not improve the predictive efficiency of the models. CONCLUSION: First-trimester ADAM12, PAPP-A, and uterine artery Doppler are not sufficiently predictive of pre-eclampsia. Combinations of these parameters do not further improve their screening efficiency

Preeclampsia is associated with reduced ISG15 levels impairing extravillous trophoblast invasion

Among several interleukin (IL)-6 family members, only IL-6 and IL-11 require a gp130 protein homodimer for intracellular signaling due to lack of intracellular signaling domain in the IL-6 receptor (IL-6R) and IL-11R. We previously reported enhanced decidual IL-6 and IL-11 levels at the maternal-fetal interface with significantly higher peri-membranous IL-6 immunostaining in adjacent interstitial trophoblasts in preeclampsia (PE) vs. gestational age (GA)-matched controls. This led us to hypothesize that competitive binding of these cytokines to the gp130 impairs extravillous trophoblast (EVT) differentiation, proliferation and/or invasion. Using global microarray analysis, the current study identified inhibition of interferon-stimulated gene 15

Succession pattern of insects in relation to killing methods of Rattus norvegicus at Delta State University, Abraka, Nigeria

The succession pattern of insects associated with the strangling and slaughtering of rat (Rattus norvegicus) was conducted between March and June 2017. Four (4) Albino Wistar rats were killed using strangle and slaughter methods, one method for a pair. The rat carcasses were secured from scavengers and restricted from human interference in a way that did not necessarily restrict access to the carcasses and also enabled insect collection. Insects were collected daily by hand picking and with the aid of aerial net, forceps and fine paintbrush. Collection was done within short period while checking the physical condition of carcass to note the stages of decay. Six insect families of three orders were collected from the carcass killed by strangling namely the Muscidae (32%), Sarcophagidae (16%), Calliphoridae (16%), Dermestidae (16%), Chrysomelidae (4%) and Cleridae (5%). In the carcass killed by slaughtering method, the families obtained were Muscidae (50%), Sarcophagidae (18%) Calliphoridae (18%), Dermestidae (9%), Staphylindae (5%). There was no significant difference (P&gt;0.05) in the succession pattern of the insects though more individuals were obtained in the strangled carcass (55%) compared to the slaughtered carcass (45%). This study shows the succession pattern may have no significant or obvious influence on the decomposition of carcasses. Therefore there is need to probe further into other killing methods.Keywords: Carcass; decomposition; forensic; strangled; slaughtere