The effect of different insect cell culture media on the efficiency of protein production by Spodoptera frugiperda cells

Critical parameters on Zika virus-like particles' generation

The Zika virus became a global threat in 2015 due to its association with microcephaly. Preventing its spread depends on developing vaccines, with virus-like particles (VLP) being a promising approach, especially because of their safety profile and high immunogenicity. This study focused on the production of Zika VLP using Sf9 cells and the baculovirus expression system, evaluating cell growth kinetics, nutrient consumption, and metabolite production in Sf-900™ III medium. As a methodology, this study includes bioreactor experiments, cell density and viability quantification, nutrient and metabolite analysis, Dot Blot, Western Blot, and transmission electron microscopy. Among the critical conditions tested are culture medium supplementation with 0.028 mM cholesterol/ 6 nM bovine serum albumin, multiplicity of infection (MOI= 0.2 or 2), and dissolved oxygen tension (DOT= 5 or 30 % air saturation). As a result, in the growth phase, Sf9 cells achieved rapid exponential growth, with doubling times ranging from 22.8 to 35.4 hours and standard nutrient consumption and metabolite generation profiles for this cell line. The infection phase recorded cell death rates between 8200 and 12600 cells mL⁻¹ h⁻¹ , with higher VLP production under low MOI (0.2) and low DOT (5 %). These conditions also reduced protein degradation and nutrient consumption. The produced VLP ranged from 32 to 73 nm in size, with smaller sizes observed under low MOI conditions. Finally, controlling the DOT at 5 % air saturation without cholesterol/albumin supplementation increased VLP production without the need to raise the viral load, highlighting the importance of choosing the appropriate combination of critical parameters (MOI, DOT, and medium supplementation) as key factors in optimizing the upstream process. This finding impacts substantially upstream stage efficiency and economy, which could be useful for future scaling up to the commercial manufacturing scale.

Establishment & characterization of a non-adherent insect cell line for cultivated meat

This study presents a blueprint for developing, scaling, and analyzing novel insect cell lines for food. The large-scale production of cultivated meat requires the development and analysis of cell lines that are simple to grow and easy to scale. Insect cells may be a favorable cell source due to their robust growth properties, adaptability to different culture conditions, and resiliency in culture. Cells were isolated from Tobacco hornworm (Manduca sexta) embryos and subsequently adapted to single-cell suspension culture in animal-free growth media. Cells were able to reach relatively high cell densities of over 20 million cells per mL in shake flasks. Cell growth data is presented in various culture vessels and spent media analysis was performed to better understand cell metabolic processes. Finally, a preliminary nutritional profile consisting of proximate, amino acid, mineral, and fatty acid analysis is reported.

Optimization of culture condition for Spodoptera frugiperda by design of experiment approach and evaluation of its effect on the expression of hemagglutinin protein of influenza virus

The baculovirus expression vector system (BEVS) is a powerful tool in pharmaceutical biotechnology to infect insect cells and produce the recombinant proteins of interest. It has been well documented that optimizing the culture condition and its supplementation through designed experiments is critical for maximum protein production. In this study, besides physicochemical parameters including incubation temperature, cell count of infection, multiplicity of infection, and feeding percentage, potential supplementary factors such as cholesterol, polyamine, galactose, pluronic-F68, glucose, L-glutamine, and ZnSO4 were screened for Spodoptera frugiperda (Sf9) cell culture and expression of hemagglutinin (HA) protein of Influenza virus via Placket-Burman design and then optimized through Box-Behnken approach. The optimized conditions were then applied for scale-up culture and the expressed r-HA protein was characterized. Optimization of selected parameters via the Box-Behnken approach indicated that feed percentage, cell count, and multiplicity of infection are the main parameters affecting r-HA expression level and potency compared to the previously established culture condition. This study demonstrated the effectiveness of designing experiments to select and optimize important parameters that potentially affect Sf9 cell culture, r-HA expression, and its potency in the BEVS system.

Heterologous Production of Antimicrobial Peptides: Notes to Consider

Heavy and irresponsible use of antibiotics in the last century has put selection pressure on the microbes to evolve even faster and develop more resilient strains. In the confrontation with such sometimes called "superbugs", the search for new sources of biochemical antibiotics seems to have reached the limit. In the last two decades, bioactive antimicrobial peptides (AMPs), which are polypeptide chains with less than 100 amino acids, have attracted the attention of many in the control of microbial pathogens, more than the other types of antibiotics. AMPs are groups of components involved in the immune response of many living organisms, and have come to light as new frontiers in fighting with microbes. AMPs are generally produced in minute amounts within organisms; therefore, to address the market, they have to be either produced on a large scale through recombinant DNA technology or to be synthesized via chemical methods. Here, heterologous expression of AMPs within bacterial, fungal, yeast, plants, and insect cells, and points that need to be considered towards their industrialization will be reviewed.

GATA binding protein 6 regulates apoptosis in silkworms through interaction with poly (ADP-ribose) polymerase

The GATA family of genes plays various roles in crucial biological processes, such as development, cell differentiation, and disease progression. However, the roles of GATA in insects have not been thoroughly explored. In this study, a genome-wide characterization of the GATA gene family in the silkworm, Bombyx mori, was conducted, revealing lineage-specific expression profiles. Notably, GATA6 is ubiquitously expressed across various developmental stages and tissues, with predominant expression in the midgut, ovaries, and Malpighian tubules. Overexpression of GATA6 inhibits cell growth and promotes apoptosis, whereas, in contrast, knockdown of PARP mitigates the apoptotic effects driven by GATA6 overexpression. Co-immunoprecipitation (co-IP) has demonstrated that GATA6 can interact with Poly (ADP-ribose) polymerase (PARP), suggesting that GATA6 may induce cell apoptosis by activating the enzyme's activity. These findings reveal a dynamic and regulatory relationship between GATA6 and PARP, suggesting a potential role for GATA6 as a key regulator in apoptosis through its interaction with PARP. This research deepens the understanding of the diverse roles of the GATA family in insects, shedding light on new avenues for studies in sericulture and pest management.

Multiple endocrine factors regulate nutrient mobilization and storage in Aedes aegypti during a gonadotrophic cycle

Anautogenous mosquitoes must blood feed on a vertebrate host to produce eggs. Each gonadotrophic cycle is subdivided into a sugar-feeding previtellogenic phase that produces primary follicles and a blood meal-activated vitellogenic phase in which large numbers of eggs synchronously mature and are laid. Multiple endocrine factors including juvenile hormone (JH), insulin-like peptides (ILPs), ovary ecdysteroidogenic hormone (OEH), and 20-hydroxyecdysone (20E) coordinate each gonadotrophic cycle. Egg formation also requires nutrients from feeding that are stored in the fat body. Regulation of egg formation is best understood in Aedes aegypti but the role different endocrine factors play in regulating nutrient mobilization and storage remains unclear. In this study, we report that adult female Ae. aegypti maintained triacylglycerol (TAG) stores during the previtellogenic phase of the first gonadotrophic cycle while glycogen stores declined. In contrast, TAG and glycogen stores were rapidly mobilized during the vitellogenic phase and then replenishment. Several genes encoding enzymes with functions in TAG and glycogen metabolism were differentially expressed in the fat body, which suggested regulation was mediated in part at the transcriptional level. Gain of function assays indicated that stored nutrients were primarily mobilized by adipokinetic hormone (AKH) while juvenoids and OEH regulated replenishment. ILP3 further showed evidence of negatively regulating certain lipolytic enzymes. Loss of function assays indicated AKH depends on the AKH receptor (AKHR) for function. Altogether, our results indicate that the opposing activities of different hormones regulate nutrient stores during a gonadotrophic cycle in Ae. aegypti.

Current Status and Nutritional Value of Green Leaf Protein

Green leaf biomass is one of the largest underutilized sources of nutrients worldwide. Whether it is purposely cultivated (forage crops, duckweed) or upcycled as a waste stream from the mass-produced agricultural crops (discarded leaves, offcuts, tops, peels, or pulp), the green biomass can be established as a viable alternative source of plant proteins in food and feed processing formulations. Rubisco is a major component of all green leaves, comprising up to 50% of soluble leaf protein, and offers many advantageous functional features in terms of essential amino acid profile, reduced allergenicity, enhanced gelation, foaming, emulsification, and textural properties. Nutrient profiles of green leaf biomass differ considerably from those of plant seeds in protein quality, vitamin and mineral concentration, and omega 6/3 fatty acid profiles. Emerging technological improvements in processing fractions, protein quality, and organoleptic profiles will enhance the nutritional quality of green leaf proteins as well as address scaling and sustainability challenges associated with the growing global demand for high quality nutrition.