Sodium butyrate improves the performance of juvenile tilapia, Oreochromis niloticus (Linneaus, 1758)

In order to evaluate the effect of sodium butyrate on the performance of juvenile tilapia 400 fish (28.55 ± 1.55 g) were used, distributed randomly in 20 tanks (250 L) connected in a closed water circulation system. For 55 days, five levels of sodium butyrate (0, 0.5, 1.0, 1.5 and 2.0 g kg-1) were tested, with each experimental unit represented by 20 fish. To evaluate the treatments, the zootechnical performance, the hepatosomatic index, the viscerosomatic relationship, the centesimal composition of the fish, the hematology and the histology of the intestine were analyzed. Significant differences were observed with quadratic behavior for fish weight gain and specific growth factor, with 1.21 g kg-1 being the best result found for weight gain, while for growth factor 1.13 g kg-1 of organic acid. The feed conversion and the viscerosomatic relationship showed linear behavior, reducing the values ​​in relation to the increase in the level of sodium butyrate. In the hematological analysis, triglyceride levels showed a significant difference for the treatment with 0.5 g kg-1, which was 190.75 mg dl-1. In the histological analysis of the intestines and fish composition, there was no significant difference between treatments. The evaluated data demonstrate an effective action of sodium butyrate with the best result for fish performance at the level of 1.21 g kg-1.

Heterologous expression of human KGF/FGF7 (Keratinocyte growth factor) in Pichia pastoris

Keratinocyte Growth Factor (KGF) is a paracrine-acting and epithelium-specific growth factor produced by cells of mesenchymal origin, play an important role in promoting proliferation, differentiation, motility of epithelial cells and stimulating regeneration of damaged epithelial tissues. Recent studies indicated that recombinant KGF is produced in many different expression systems such as bacteria, insect cells, plant and mammalian cells. However, KGF’s yields obtained from these systems is low and production’s cost is high especially in mammalian cells. In this study, the yeast Pichia pastoris was chosen as a host for KGF expression through induction of methanol by promoter AOX on pPICzαA vector system. The results demonstrated that the Pichia pastoris X33:kgf transformants secreted KGF directly into BMMY medium after inducing by 0.5% methanol. The recombinant protein was purified by heparin affinity chromatography with the yield of 1.35 mg/l and the purity of 99.89% showed by SDS-PAGE. In addition, MTT assay showed the purified recombinant KGF had a proliferation effect on A549 cell line since A549 known as a cell has KGF’s receptor.

Cell-to-cell diversification in ERBB-RAS-MAPK signal transduction that produces cell-type specific growth factor responses

Growth factors regulate cell fates, including their proliferation, differentiation, survival, and death, according to the cell type. Even when the response to a specific growth factor is deterministic for collective cell behavior, significant levels of fluctuation are often observed between single cells. Statistical analyses of single-cell responses provide insights into the mechanism of cell fate decisions but very little is known about the distributions of the internal states of cells responding to growth factors. Using multi-color immunofluorescent staining, we have here detected the phosphorylation of seven elements in the early response of the ERBB–RAS–MAPK system to two growth factors. Among these seven elements, five were analyzed simultaneously in distinct combinations in the same single cells. Although principle component analysis suggested cell-type and input specific phosphorylation patterns, cell-to-cell fluctuation was large. Mutual information analysis suggested that cells use multitrack (bush-like) signal transduction pathways under conditions in which clear cell fate changes have been reported. The clustering of single-cell response patterns indicated that the fate change in a cell population correlates with the large entropy of the response, suggesting a bet-hedging strategy is used in decision making. A comparison of true and randomized datasets further indicated that this large variation is not produced by simple reaction noise, but is defined by the properties of the signal-processing network.Author SummaryHow extracellular signals, such as growth factors (GFs), induce fate changes in biological cells is still not fully understood. Some GFs induce cell proliferation and others induce differentiation by stimulating a common reaction network. Although the response to each GF is reproducible for a cell population, not all single cells respond similarly. The question that arises is whether a certain GF conducts all the responding cells in the same direction during a fate change, or if it initially stimulates a variety of behaviors among single cells, from which the cells that move in the appropriate direction are later selected. Our current statistical analysis of single-cell responses suggests that the latter process, which is called a bet-hedging mechanism is plausible. The complex pathways of signal transmission seem to be responsible for this bet-hedging.

Scaling-up sustainable Chlorella vulgaris microalgal biomass cultivation from laboratory to pilot-plant photobioreactor, towards biofuel

<p>Unicellular microalgal culture represents a new opportunity for producing significant biofuel quantities in the future along with other specialty products, due to several major advantages microalgae species present when compared to conventional crops, including much faster growth rates, cultivation in a variety of environments and photobioreactor systems, and almost 100% recycling of nutrients. In the current research, the scaling-up of the cultivation of Chlorella vulgaris microalgae to a 4 m3 pilot-plant photobioreactor is examined, compared to the performance of a 25 L automated laboratory bioreactor. Beyond the size and configuration, the main differences of the two bioreactors are the mode of operation, the illumination nature and depth, the temperature, and pH. Specifically, temperature and illumination are naturally varying from day to day and season to season into the pilot-plant photobioreactor that is set inside a greenhouse. The specific growth factor appears to be higher for microalgal cultivation in the laboratory bioreactor. It is also found that the growth kinetics is severely slowed down during the winter months. This is primarily due to the low temperatures and the poor illumination observed during winter.</p>