Growth inhibition of shrimp pathogens by isolated gastrointestinal microflora of Macrobrachium rosenbergii de Man

The useful bacteria which were isolated from the gastrointestinal tract of freshwater prawn (Macrobrachium rosenbergii de Man), cultivated in earthen pond at Maha Sarakham province, Thailand, consisted of 14 isolates of Bacillus (B1 – B14) and 18 isolates of Lactic acid bacteria (LA1 – LA18). The abilities of all isolated bacteria on growth inhibition of pathogenic bacteria (Escherichia coli, Bacillus cereus, Aeromonas hydrophila and Pseudomonas aeruginosa) were studied by paperdisc plate method. The results showed that the Bacillus B2 and B5 were unable to inhibit the growth of all of the tested pathogens. Bacillus B1, B10 and B12 were capable of inhibiting the growth of 3 of 4 tested pathogen strains. Although all of the isolated lactic acid bacteria (LA1 –LA18) could not inhibit the E. coli growth, all of them could inhibit the growth of B. cereus. The isolated lactic acid bacteria which were capable of inhibiting the growth of 3 tested pathogen strains (excluded E. coli) were LA12 , LA13 , LA14 , LA15 , LA16 , LA17 and LA18. In order to select the high potential strain of bacteria for using as probiotics, Bacillus B1 , B3 , B4 , B10 and B12 and lactic acid bacteria LA12 , LA13 , LA14 , LA15 , LA16 , LA17 and LA18 were tested for their growth abilities in various growth conditions. The tested growth conditions included various concentrations of the bile salt and salt (NaCl) and various pH and temperatures. The results revealed that Bacillus B1 and B10 and lactic acid bacteria LA13 , LA16 and LA18 exhibited high potential for using as probiotics. The results of biochemical test for identification of these high potential strains showed that Bacillus B1 and B10 were possibly B. licheniformis and B. thuringiensis respectively. The lactic acid bacteria LA13 , LA16 and LA18 were possibly the same strain and belonged to the genus Pediococcus

Author Correction: Diversity in gut bacterial community of school-age children in Asia (Scientific Reports, (2015), 5, 1, (8397), 10.1038/srep08397)

10.1038/s41598-019-42780-zScientific Reports91653

Plant protein hydrolysates support CHO-320 cells proliferation and recombinant IFN-gamma production in suspension and inside microcarriers in protein-free media

We have recently developed a protein-free medium (PFS) able to support the growth of Chinese hamster ovary (CHO) cells in suspension. Upon further supplementation with some plant protein hydrolysates. medium performances reached what could be observed in serum-containing media [Burteau et al. In Vitro Cell. Dei,. Biol.-Anhn. 39 (2003) 291]. Now, we describe the use of rice and wheat protein hydrolysates. as non-nutritional additives to the culture medium to support productivity and cell growth in suspension or in microcarriers. When CHO-320 cells secreting recombinant interferon-gamma were cultivated in suspension in a bioreactor with our PFS supplemented with wheat hydrolysates. the maximum cell density increased by 25% and the IFN-gamma secretion by 60% compared to the control PFS. A small-scale perfusion system consisting of CHO-320 cells growing on and inside fibrous microcarriers under discontinuous operation was first developed. Under these conditions: rice protein hydrolysates stimulated recombinant IFN-gamma secretion by 30% compared to the control PFS. At the bioreactorscale. similar results were obtained but when compared to shake-flasks studies, nutrients, oxygen or toxic by-products gradients inside the microcarriers seemed to be the main limitation of the system. An increase of the perfusion rate to maintain glucose concentration over 5.5 mM and dissolved oxygen (DO) at 60% was able to stimulate the production of IFN-gamma to a level of 6.6 mug h(-1) g(-1) of microcarriers after 160 h when a cellular density of about 4 x 10 cell g(-1) of carriers was reached