Toxoplasma gondii destroys Her2/Neu-expressing mammary cancer cells in vitro using a continuous feed medium approach

Introduction: Toxoplasma gondii is an opportunistic protozoan and can be grown using several human cell lines. Breast cancer is the second leading cause of cancer death in women. Her2/Neu-expressing mammary cancer cell lines called TUBO can be grown in vitro. In recent years, protozoan parasites have become popular means of use in cancer therapy research. In this study, we analyzed whether T. gondii tachyzoites can destroy TUBO cells using a novel continuous feed medium approach. Methodology: Two sets of flasks (each containing four groups) containing TUBO cells were inoculated with T. gondii Ankara strain tachyzoites. First set containing 5×106 TUBO cells were inoculated with TUBO-tachyzoite ratios of 1:2, 1:1, 2:1, and 4:1 and second set containing 1×106 TUBO cells were inoculated with TUBO-tachyzoite ratios of 10:1, 100:1, 1000:1, and 2000:1. Thereafter, culture supernatants were harvested at various days until TUBO cells were destroyed and tachyzoites were counted. Results: In the first and second sets of flasks, TUBO cells were destroyed between days 8 to 12 and 12 to 25, respectively. In addition, the amount of tachyzoites increased 7- 43 and 595 to 112500 times in the first and second set of flasks, respectively. Conclusions: These results show that T. gondii tachyzoites successfully destroy Her2/Neu-expressing mammary cancer cells using a continuous feed medium approach. Although this idea may be too premature for the moment, the approach defined herein may support future researchers investigating the relationship between cancer and parasites which can make important progress toward saving cancer patient lives.

Yeast biomass production with potential for biological control: process strategies for increasing yield

The quality of vegetable products is directly linked to the techniques used in the field, in order to ensure safe and healthy products to health. In this context, the use of yeasts with potential for biological control proved to be a promising alternative to assure the safety of these foods. Fermentation processes have been used to promote the development of many products, including the production of yeast biomass. The objective of this work was to verify the influence of the aeration rate and the fed batch process in the production of yeast biomass. A yeast strain with biological control potential, belonging to Embrapa's Semi-Arid crop collection, was subjected to simple batch cultivation and fed with different aeration rates (3, 4, 6 and 8 L.ar/min) and concentration of carbon source in the feed medium (200, 400 and 600 g/L). The highest biomass (6.99 g/L) after 24 hours of fermentation was observed in the experiment that used an aeration rate of 8 L.ar/min. Regarding the concentration of the carbon source in the feed medium, it was found that the concentration of 200 g/L favored a greater total biomass (11.21 g/L) and reduced the production of ethanol (0.65 g/L ), while the concentration of 600 g/L favored less biomass production (7.90 g/L) and higher ethanol production (9.26 g/L). Thus, it was found that the aeration rate and the fed batch process favor the fermentation strategy, as they contribute to the production of yeast biomass and the overall yield of the process.

Towards the development of automated fed-batch cell culture processes at microscale

Aim: To investigate the impact of various feeding strategies on the growth and productivity of a GS-CHO cell line. Methods: Feed additions were conducted at fixed volumes or linked to a marker such as cell growth or metabolism and added as bolus or near-continuously using the automated feeding module of the micro-Matrix (Applikon). Results: The selected feeding regimens supported maximum viable cell densities of up to 1.9 × 107 cells ml−1 and final titers of up to 1.13 g l−1. Differences in growth and titer between feeding strategies were insignificant, with the exception of one feeding strategy. Conclusion: As the more complex feeding strategies did not create an advantage, the selection of a simple feeding strategy such as bolus or continuous addition of feed medium is preferred.

UJI VIABILITAS BAKTERI ASAM LAKTAT DARI USUS YANG DIPREPARASI DALAM RANSUM UNGGAS

The aim of this study is to know the viability of Lactic Acid Bacteria isolates on ration and combination of ration with molasses. This study used a mixture of lactic acid bacteria isolates from the duck intestine (B4, B7, B8). The third bacterial isolates were inoculated on two different treatment media, on rantion media (R1), and combination of rantion + molasses (R2). The study was arranged by randomized block design (RAK) 6x2 factorial treatment pattern. Factor A is the incubation time of 0 hours, 2 hours, 4 hours, 6 hours, 8 hours and 10 hours. Factor B is two types of growing media of lactic acid bacteria, is ransum media, and combination of ransum + molasses. Each treatment was repeated 3 times. This research uses pour plate method with the calculation of the colony using colony counter. Data analyzed descriptively. The results showed that the addition of 1.6% molasses (R2) maintains the number of LAB population at 4th hour with the cell number 7,36 x 105 CFU / g. While on the ration medium (R1) can maintain the amount of LAB at 6th hour with the cell number of 6,20 x 105 CFU / g. LAB population viability on feed medium with addition of molases 1.6% (R2) has increased on storage time at 4th hour with cell number 7,36 x 105 CFU / g, while on feed medium (R1) decreased cell count 6,08 x 105 CFU / g. Keywords: Viability, Lactic Acid Bacteria, Ransum, Molase.

Stability and Oscillation Phenomena Analysis in Microbial Continuous Fermentation Time-Delay System

Based on 1,3-propanediol production from continuous fermentation of glycerol by Klebsiellapneumoniae, the dynamic behaviors of a kinetics system with continuous time-delay are analyzed. At first, a six-dimension kinetics system concerning the intracellular substance is proposed by introducing weak nuclear continuous time-delay into the specific cellular growth rate. Second, taking the inverse of average time-delay as parameter, the local stability of the positive equilibriums and the existence of Hopf bifurcation are discussed. Finally, the period solution of biomass and the parameter region of Hopf bifurcation are pictured numerically taking some special number in substrate concentration in feed medium and dilution rate.