Replacement of fetal calf serum in cell cultures by an egg yolk factor with cholecystokinin/gastrin-like immunoreactivity

Preliminary study on comparison of egg extraction methods for development of fetal bovine serum substitutes in cultured meat

Fetal bovine serum (FBS) substitution remains one of the challenges to the realization of cultured meat production in the marketplace. In this study, three methods were developed to extract a substitute for FBS using egg white extract (EWE): using 25 mM CaCl2/2.5 % ammonium sulfate/citric acid (A); ethyl alcohol (B); and 5 % ammonium sulfate/citric acid (C). B EWE can effectively replace up to 50 % of FBS in growth media (10 % of the total). Ovalbumin in the extracts can promote cell proliferation, and components along the 12 kDa protein band have the potential to inhibit cell proliferation. Chick primary muscle cells applied with B EWE, an edible material that improved the cost and time efficiency of cultured meat production, effectively proliferated/differentiated. Therefore, EWE extracted using ethyl alcohol may be used as an FBS substitute to reduce animal sacrifices and should be considered a viable alternative to FBS for cultured meat.

Perkinsus marinus in bioreactor: growth and a cost-reduced growth medium

Perkinsus marinus (Perkinsea) is an osmotrophic facultative intracellular marine protozoan responsible for "Dermo" disease in the eastern oyster, Crassostrea virginica. In 1993 in vitro culture of P. marinus was developed in the absence of host cells. Compared to most intracellular protozoan parasites, the availability of P. marinus to grow in the absence of host cells has provided the basis to explore its use as a heterologous expression system. As the genetic toolbox is becoming available, there is also the need for larger-scale cultivation and lower-cost media formulations. Here, we took an industrial approach to scaled-up growth from a small culture flask to bioreactors, which required developing new cultivation parameters, including aeration, mixing, pH, temperature control, and media formulation. Our approach also enabled more real-time data collection on growth. The bioreactor cultivation method showed similar or accelerated growth rates of P. marinus compared to culture in T-flasks. Redox measurements indicated sufficient oxygen availability throughout the cultivation. Replacing fetal bovine serum with chicken serum showed no differences in the growth rate and a 60% reduction in the medium cost. This study opens the door to furthering P. marinus as a valid heterologous expression system by showing the ability to grow in bioreactors.

ONE-SENTENCE SUMMARY

Perkinsus marinus, a microbial parasite of oysters that could be useful for developing vaccines for humans, has been shown to grow well in laboratory equipment that can be expanded to commercial scale using a less expensive growth formula than usual laboratory practice.

Comparison of camel, dog and the laboratory animals' sera with the fetal calf serum (FCS) for cultivation of Leishmania major

The best-known serum for Leishmania spp. cultivation is the fetal calf serum (FCS), which is very expensive with ethical concerns. This study was conducted to compare various laboratory (BALB/c mice, rat, rabbit, hamster and guinea pig) and non-laboratory (dog and camel) animals' sera as a substitute for FCS in L. major culture. L. major, MRHO/IR/75/ER strain, was cultivated in RPMI-1640 medium enriched with different percentages of mentioned animal's sera. Parasite growth was checked constantly. The rate of growth and survival of parasites were compared with a control medium enriched with FCS. As well, biochemical (albumin, globulin AST, ALT, ALP, Bil, BUN, Crea, Ca, P, Na, K, Fe, TIBC, Mg, zinc, Chol, HDL, LDL, TG, BS, uric acid, LDH, CPK) analysis of all sera was performed and compared with FCS. The most promastigote growth rate is considered in 10% BALB/c, guinea pig and hamster sera on the 6th day of cultivation. Also, on the 8th day, parasites showed viability in all animal sera. The promastigote growth in culture media enriched with the camel and the dog sera in comparison with laboratory animals was considered very low. Differences between 10% FCS and 10% cocktail serum were not significant (p > 0.05) but with other sera were significant (p < 0.05). Also, differences between BALB/c with hamster and guinea pig sera were not significant, respectively (p = 0.07 and p = 0.09). According to the biochemical analysis of all sera, the higher content of iron was detected in the hamster, guinea pig, BALB/c and fetal calf sera. The magnesium and zinc content of guinea pig and BALB/c serum was found to be more than the others and comparable with FCS. The promastigote growth decreased by camel, dog and rat sera orderly. In this study, a rapid increase in parasite growth in media supplemented with hamster, BALB/c and guinea pig sera was considered. It could be suggested to use these sera as a suitable alternative for FCS in molecular biology researches.

Differential gene expression in porcine oviduct during the oestrous cycle

The oviduct undergoes changes under the influence of steroid hormones during the oestrous cycle. However, the molecular mechanisms underlying oviductal regulation are not fully understood. The aim of the present study was to identify the gene expression profile of the porcine oviduct in different stages of the cycle using microarray technology. A systematic study was performed on animals at four different stage: prepubertal gilts, and sows in the preovulatory, postovulatory and luteal phase of the oestrous cycle. The porcine oviduct expressed a total of 4929 genes. Moreover, significant differences in the expression of several genes were detected as the oestrous cycle progressed. Analysis of the differentially expressed genes indicated that a total of 86, 89 and 15 genes were upregulated in prepubertal gilts, preovulatory and luteal sows respectively compared with levels observed in postovulatory sows. Moreover, 80, 51 and 64 genes were downregulated in prepubertal, preovulatory and luteal animals respectively compared with the postovulatory sows. The concentrations of 10 selected transcripts were quantified by real-time reverse transcription–polymerase chain reaction to validate the cDNA array hybridisation data. Conversely, for some genes, localisation of corresponding protein expression in the oviduct was analysed by immunohistochemistry (i.e. cholecystokinin, glutathione peroxidase 2, mucin 1, phosphatidylethanolamine binding protein 4 and tachykinin 3) and mass spectrometry analysis of oviductal fluid allowed identification of peptides from all five proteins. The results of the present study demonstrate that gene expression in the porcine oviduct is clearly regulated during the oestrous cycle, with some oviductal proteins that could be related to several reproductive processes described here for the first time.

Differentiation of adipose-derived stem cells into Schwann-like cells: fetal bovine serum or human serum?

Access to autologous Schwann cells is limited due to lack of donor site and its difficult isolation and culture. Therefore, one of the possible ways to obtain to Schwann cells is to differentiate mesenchymal stem cells into glial pathway using various materials and protocols. The aim of this study was to compare the effects of fetal bovine serum and human serum on Schwann cell differentiation of adipose-derived stem cells to choose the best serum for use in future research. For this purpose, after isolation of human adipose-derived stem cells, it was characterized and differentiated into Schwann cell lineage using two protocols which one of them contained fetal bovine serum and the other human serum. At the end, morphological evaluation declared an increased detachment of cells in response to human serum. On the other side, immunocytochemistry showed that there was a significant increase in the number of cells expressing glial fibrillary acidic proteins and S100 in fetal bovine serum-treated group when compared to human serum-treated one (P<0.05). It was concluded that fetal bovine serum was more effective than allogeneic human serum in Schwann cell differentiation of adipose-derived stem cells.

Human umbilical cord blood serum promotes growth, proliferation, as well as differentiation of human bone marrow-derived progenitor cells

Fetal calf serum (FCS) is conventionally used for animal cell cultures due to its inherent growth-promoting activities. However animal welfare issues and stringent requirements for human transplantation studies demand a suitable alternative for FCS. With this view, we studied the effect of FCS, human AB serum (ABS), and human umbilical cord blood serum (UCBS) on murine islets of Langerhans and human bone marrow-derived mesenchymal-like cells (hBMCs). We found that there was no difference in morphology and functionality of mouse islets cultured in any of these three different serum supplements as indicated by insulin immunostaining. A comparative analysis of hBMCs maintained in each of these three different serum supplements demonstrated that UCBS supplemented media better supported proliferation of hBMCs. Moreover, a modification of adipogenic differentiation protocol using UCBS indicates that it can be used as a supplement to support differentiation of hBMCs into adipocytes. Our results demonstrate that UCBS not only is suitable for maintenance of murine pancreatic islets, but also supports attachment, propagation, and differentiation of hBMCs in vitro. We conclude that UCBS can serve as a better serum supplement for growth, maintenance, and differentiation of hBMCs, making it a more suitable supplement in cell systems that have therapeutic potential in human transplantation programs.

Primary mantle tissue culture from the bivalve mollusc Mytilus galloprovincialis: Investigations on the growth promoting activity of the serum used for medium supplementation

The main objective of the present work was to evaluate with a quantitative approach the effects of different chicken serum (CS) concentrations in the medium used for mussel mantle tissue culturing. Our results showed that a CS level of 20% was optimal. Under these conditions, the cultures reached a maximum mean number of mitotic figures per slide exceeding widely 100. Cultures were also achieved to test whether CS must be heat treated to inactivate complement components before use for medium enrichment. We demonstrated that heat inactivation did not significantly change the promoting activity of the CS. Finally, the growth-stimulatory properties of CS were compared to those of fetal calf serum (FCS). The best results were obtained with 30% FCS. The difference with 20% CS was not statistically significant, but the FCS yielded a much higher level of polyploid metaphases than the CS. Since it had no adverse effect such as polyploid metaphases induction, was readily commercially available and relatively less expensive than other additives, CS at the concentration of 20%, without heat-decomplementation, is routinely used as growth medium supplement for mussel mantle cell culturing in our laboratory. Even though our primary cultures do not have the potency of continuous cell lines, it is possible to use such cultures for in vitro experiments.

Production, purification, and characterization of rat pro-CCK from serum-free adapted Drosophila cells

The precursor of cholecystokinin (pro-CCK) was expressed and purified from media of stably transfected D.Mel-2 cell as an V5-His tagged fusion protein. Its identity was confirmed using SDS-PAGE, immunoblotting, gel filtration chromatography, HPLC, and Mass Spectroscopy. Two major forms of pro-CCK were found with a molecular weight of about 14.4 and 11.3 kDa. The smaller form represents the V5-His tagged pro-CCK after cleavage at a single arginine residue at CCK-58. This cleavage is probably being performed by endogenous proteases in these cells. Purification of the desired larger form of pro-CCK is possible using a nickel column with a recovery of about 20%, yielding 500 microg/L media. The purified protein is stable for several months and can be used for further functional studies of pro-CCK.