Large-scale Culture Research Articles

The Liquid-Fermentation Formulation of Sanghuangporus sanghuang Optimized by Response Surface Methodology and Evaluation of Biological Activity of Extracellular Polysaccharides.

Sanghuangporus sanghuang is a rare fungus growing on mulberry trees that has immense medicinal value. This study aimed to optimize the liquid-fermentation-media formulation and culture conditions for large-scale culturing of S. sanghuang by performing one-way testing and response surface methodology. The antioxidant and anticancer activities of the extracellular polysaccharides from S. sanghuang were also analyzed. The optimal formulation and growth conditions for S. sanghuang were as follows: glucose, 30.2 ± 0.37 g/L; yeast extract, 14.60 ± 0.05 g/L; dandelion powder, 1.24 ± 0.01 g/L; shaker speed, 150 r/min; and temperature, 25 °C. We obtained 13.99 ± 0.42 g/L of mycelium biomass by culturing S. sanghuang for 15 days with the optimized formulation. This was 2-fold higher than the mycelial mass obtained with the sub-optimal formulation. The extracellular fungal polysaccharides showed significant antioxidant activity against ABTS and DPPH free radicals, and significantly reduced the in vitro growth and survival of several cancer cell lines. The anticancer activity of the extracellular fungal polysaccharides was significantly higher in the human glioma cells than in other cancer cell lines. In summary, this study optimized the liquid media formulation and conditions for the large-scale culturing of S. sanghuang. Furthermore, the extracellular polysaccharides from S. sanghuang showed significant antioxidant and anticancer activities.

Investigation on the enhancement of crack restoration properties in cement incorporated with Arthrospira platensis cultured in modified medium.

This study investigated the potential use of microalgae as partial cement replacement to heal cracks in cement mortar. Microbially induced calcite (CaCO3) precipitation (MICP) from Arthrospira platensis (A. platensis) (UMACC162) was utilised for crack-healingapplications. Microalgaewascultivated in Kosaric Media (KM)together with filtered cement water (FCW), andused asa cement replacement material. The microalgal species was furtherevaluated for its capacity and adaptability towards large-scale culturing. The results showed that A. platensis could adapt and survive in cement water solution and cement mortar, suggesting the potential for self-healing in cement mortar. Further, the cultured species grown in both conditions(KM and KM & FCW) were harvested and incorporated into the cement mortar as a partial cementreplacement material atdifferent levels of 5%, 10%, 20%, and 30% of cementweight. The cement mortars partially replaced withmicroalgae were cured in water for 28 days. Pre-cracks were induced in the cured mortar with the 75% of their ultimate load. It took just 14 days for the microalgae-incorporated mortar to heal the cracks. The specimens with microalgae cultured in FCW showeda better performance and recovered 59% of their strength, with a maximum healed crack width of 0.7 mm. In terms of water tightness and porosity, they are comparable to the control mortar. The compressive strength measurements indicated the formation of calcite aggregate (crystal) that sealed the surface cracks, which was confirmed by a microstructural analysis. The results also demonstrate that the incorporation of microalgae into cement produced a self-healing effect, providing a new direction for crack healing. Additionally, the investigation indicated that replacing cement withmicroalgae reduced CO2 emissions by as much as 30%, with a substitution of 30% of microalgae. Exploring microalgae as a cement replacement could reduce carbon emissions and improve the state of the environment.

Long-term response of plankton assemblage to differentiated nutrient reductions in Laizhou Bay, China

Nutrient reductions are considered effective methods to control eutrophication; however, our understanding of how plankton assemblages respond to nutrient reductions is limited. In the present study, we used a long-term dataset between 2004 and 2018 from Laizhou Bay, China, to describe the main characteristics of plankton assemblage response to nutrient reduction, and to compare the differences in plankton response between the different nutrient reduction regions. The results showed that plankton abundance showed obvious decreasing trends in response to nutrient reductions. The phytoplankton abundance decline rate was directly proportional to the magnitude of nutrient reductions. The large-scale shellfish culture may disrupt the response of mesozooplankton to nutrient reductions. Positive recovery signs in the plankton community were observed with species dominance decreasing for small individuals and increasing for large ones. The results suggested that the reduction in nitrogen and phosphorus positively affected plankton abundance and community recovery in Laizhou Bay.

Culturable Streptomyces spp. from high-altitude, oligotrophic North Western Himalaya: a comprehensive study on the diversity, bioactivity and insights into the proteome of potential species.

The increasing global concern of antimicrobial resistance and shortage of new antimicrobials necessitates exploring untapped terrestrial environments for new bioactive microbiome diversity. The low-temperature and oligotrophic North Western Himalaya (NWH) region has a vast diversity of Streptomyces with potential antimicrobial properties that remain largely unexplored. This study evaluates the diversity of culturable Streptomyces from high-altitude NWH and their potential as a source of new antimicrobials through genus-specific isolation and identification. The results demonstrate a distinct phylogenetic clustering of Streptomyces from different sampling regions of NWH, site-specific variation in culturable β-diversity and species commonness with varying intersite bioactivity among different sites. Further, the study optimized the media selection for large-scale culture cultivation in antibiotic production processes and demonstrated the antimicrobial efficacy of Streptomyces against a range of pathogens through in vitro bioassays using minimum inhibitory concentration determination and antibiofilm activity. Untargeted label-free proteomic profiling also revealed variable expression of stress-response proteins and antibiotic regulators as a competitive survival strategy for selective antagonistic Streptomyces. The findings highlight the potential of NWH in augmenting antimicrobial discovery and combating antimicrobial resistance through the isolation and study of novel bioactive Streptomyces.

A strategy of novel molecular hydrogen-producing antioxidative auxiliary system improves virus production in cell bioreactor

In the increasing demand for virus vaccines, large-scale production of safe, efficient, and economical viral antigens has become a significant challenge. High-cell-density manufacturing processes are the most commonly used to produce vaccine antigens and protein drugs. However, the cellular stress response in large-scale cell culture may directly affect host cell growth and metabolism, reducing antigen production and increasing production costs. This study provided a novel strategy of the antioxidant auxiliary system (AAS) to supply molecular hydrogen (H2) into the cell culture media via proton exchange membrane (PEM) electrolysis. Integrated with a high-density cell bioreactor, the AAS aims to alleviate cellular stress response and increase viral vaccine production. In the results, the AAS stably maintained H2 concentration in media even in the high-air exposure tiding cell bioreactor. H2 treatment was shown safe to cell culture and effectively alleviated oxidative stress. In two established virus cultures models, bovine epidemic fever virus (BEFV) and porcine circovirus virus type 2 (PCV-2), were employed to verify the efficacy of AAS. The virus yield was increased by 3.7 and 2.5 folds in BEFV and PCV-2 respectively. In conclusion, the AAS-connected bioreactor effectively alleviated cellular oxidative stress and enhanced virus production in high-density cell culture.

Large-scale culturing of the subpolar foraminifera Globigerina bulloides reveals tolerance to a large range of environmental parameters associated to different life-strategies and an extended lifespan.

The subtropical to subpolar planktic foraminifera Globigerina bulloides is a calcifying marine protist, and one of the dominant foraminiferal species of the Nordic Seas. Previously, the relative abundance and shell geochemistry of fossil G. bulloides have been studied for palaeoceanographic reconstructions. There is however a lack of biological observations on the species and a poor understanding of its ecological tolerances, especially for high latitude genotypes. Here, we present observations from the first extensive culturing of G. bulloides under subpolar conditions, including the first low temperature (6-13°C) and variable salinity (30-38) experiments. Carbonate chemistry (pH and [CO3 2-]) was also manipulated. Experimental conditions were chosen to reflect a range of plausible past and future scenarios for the Nordic Seas. We found G. bulloides to be tolerant of environmental conditions well outside their optimal range (<10°C, salinity <33, pH <8). Observed life span was up to three months, which was attributed to a microalgal diet. Two alternative life strategies were employed, whereby individuals either experienced rapid growth and death, or a prolonged lifespan with minimal growth and death via slow decay. We posit this could help explain differences in geochemical signals recorded from different size fractions of fossil specimens used for palaeoceanographic reconstructions.

Development of bioreactor scale-down model using orthogonal projections to latent structures method and CO2 supplementation.

Scale-down model qualification is an important step for developing a large-scale cell culture process to enhance process understanding and support process characterization studies. Traditionally, only harvest data are used to show consistency between small-scale and large-scale bioreactor performance, allowing attributes that are dynamic over the cell culture period to be overlooked. A novel statistical method, orthogonal projections to latent structures (OPLS) analysis, can be utilized to compare time-course cell culture data across scales. Here we describe an example where OPLS is used to identify gaps between small-scale and large-scale bioreactor performances. In this case, differences in the partial pressure of carbon dioxide (pCO2) and lactate profiles were observed between small- and large-scale bioreactors, which were linked to differences in the product-quality attributes fragments and galactosylation. An improved small-scale model was developed, leading to improved consistency in the process performance and product qualities across scales and qualification of the scale-down model for regulatory submissions. This new statistical approach can provide valuable insights into process understanding and process scale-up.

Large-Scale Culture and Plasmid Preparation Procedure for Low-Yield Bacmids Containing Full-Length SARS-CoV-2 cDNAs.

Reverse genetic methods to manipulate viral genomes are key tools in modern virological experimentation. They allow for the generation of reporter virus genomes to simplify the assessment of virus growth and for the analysis of the impact of specific mutations in the genome on virus phenotypes. For SARS-CoV-2, reverse genetic systems are complicated by the large size of the viral genome and the instability of certain genomic sections in bacteria requiring the use of low-copy number bacterial artificial chromosome plasmids (bacmids). However, even with the use of bacmids, faithfully amplifying SARS-CoV-2 bacmids is often challenging. In this chapter, we describe a detailed protocol to grow SARS-CoV-2 bacmids and highlight the challenges and optimal techniques to produce large quantities of SARS-CoV-2 bacmids that are free of deletions and mutations. Overall, this chapter has recapitulated an overview of the maxi-preparation procedure for large unstable bacmids like SARS-CoV-2 to facilitate downstream applications.

Selective expansion of renal cancer stem cells using microfluidic single-cell culture arrays for anticancer drug testing.

The suboptimal prognosis associated with drug therapy for renal cancer can be attributed to the presence of stem-cell-like renal cancer cells. However, the limited number of these cells prevents conventional drug screening assays from effectively assessing the response of renal cancer stem cells to anti-cancer agents. To address this issue, the present study employed microfluidic single-cell culture arrays to expand renal cancer stem cells by exploiting the anti-apoptosis and self-renewal properties of tumor stem cells. A microfluidic chip with 18 000 hydrophilic microwells was designed and fabricated to establish the single-cell culture array. Over a 7 day culture, the large-scale single-cell culture yielded a limited quantity of single-cell-derived tumorspheres. The sphere formation rates for Caki-1, 786-O, and ACHN cells were determined to be 8.74 ± 0.53%, 12.02 ± 1.43%, and 4.98 ± 1.68%, respectively. The expanded cells exhibited stemness characteristics, as indicated by immunofluorescence, flow cytometry, serial passaging, and in vitro differentiation assays. Additionally, the comparative transcriptomic analysis showed significant differences in the gene expression patterns of the expanded cells compared to the differentiated renal cancer cells. The drug testing indicated that renal cancer stem cells exhibited reduced sensitivity towards the tyrosine kinase inhibitors sorafenib and sunitinib, compared to differentiated renal cancer cells. This reduced sensitivity can be attributed to the elevated expression levels of tyrosine kinase in renal cancer stem cells. This present study provides evidence that the utilization of microfluidic single-cell culture arrays for selective cell expansion can facilitate drug testing of renal cancer stem cells.

Gastrointestinal tract organoids as novel tools in drug discovery.

Organoids, characterized by their high physiological attributes, effectively preserve the genetic characteristics, physiological structure, and function of the simulated organs. Since the inception of small intestine organoids, other organoids for organs including the liver, lungs, stomach, and pancreas have subsequently been developed. However, a comprehensive summary and discussion of research findings on gastrointestinal tract (GIT) organoids as disease models and drug screening platforms is currently lacking. Herein, in this review, we address diseases related to GIT organoid simulation and highlight the notable advancements that have been made in drug screening and pharmacokinetics, as well as in disease research and treatment using GIT organoids. Organoids of GIT diseases, including inflammatory bowel disease, irritable bowel syndrome, necrotizing enterocolitis, and Helicobacter pylori infection, have been successfully constructed. These models have facilitated the study of the mechanisms and effects of various drugs, such as metformin, Schisandrin C, and prednisolone, in these diseases. Furthermore, GIT organoids have been used to investigate viruses that elicit GIT reactions, including Norovirus, SARS-CoV-2, and rotavirus. Previous studies by using GIT organoids have shown that dasabuvir, gemcitabine, and imatinib possess the capability to inhibit viral replication. Notably, GIT organoids can mimic GIT responses to therapeutic drugs at the onset of disease. The GIT toxicities of compounds like gefitinib, doxorubicin, and sunset yellow have also been evaluated. Additionally, these organoids are instrumental for the study of immune regulation, post-radiation intestinal epithelial repair, treatment for cystic fibrosis and diabetes, the development of novel drug delivery systems, and research into the GIT microbiome. The recent use of conditioned media as a culture method for replacing recombinant hepatocyte growth factor has significantly reduced the cost associated with human GIT organoid culture. This advancement paves the way for large-scale culture and compound screening of GIT organoids. Despite the ongoing challenges in GIT organoid development (e.g., their inability to exist in pairs, limited cell types, and singular drug exposure mode), these organoids hold considerable potential for drug screening. The use of GIT organoids in this context holds great promises to enhance the precision of medical treatments for patients living with GIT diseases.

Application of Biofloc Technology in Rearing of Two IMC Fish Species Cirrhinus mrigala and Labeo rohita and Estimation of Length – Weight Relationship under the Same Feeding Regime

Biofloc technology (BFT) is an innovative technology which is based upon zero or minimal water exchange where heterotrophic bacteria which consume organic carbon are grown on unconsumed feed, fish excreta and inorganic nitrogenous products resulting in the removal of these unwanted components from the water. The present study demonstrates the effective application of Biofloc technology to culture Indian Major Carps (mainly C. mrigala and L. rohita) in semi-indoor conditions with less water requirements. After conducting the study for a period of 6 months, relationship between length-weight was derived in both the fishes. The value of ‘b’ showed an increase with 2.8701 (in C. mrigala) and 2.7567 (in L. rohita) after the study period. The value of Kn lied within the range of 0.9545-1.0511 (in C. mrigala) and 0.925-1.01 (in L. rohita). Coefficient of determination (R2) and correlation coefficient (r) were prominent with R2=0.9071 (r=0.952) and R2=0.9517 (r=0.975) in C. mrigala and L. rohita respectively. The findings of the current study demonstrates that IMC can be reared effectively using this technique rather than going for large scale culture where cost of feed and space limitation is a major problem.

Establishment of an Efficient Expression and Regulation System in Streptomyces for Economical and High-Level Production of the Natural Blue Pigment Indigoidine.

Indigoidine, as a kind of natural blue pigment, is widely used in textiles, food, and pharmaceuticals and is mainly synthesized from l-glutamine via a condensation reaction by indigoidine synthetases, most of which originates from Streptomyces species. However, due to the complex metabolic switches of Streptomyces, most of the researchers choose to overexpress indigoidine synthetases in the heterologous host to achieve high-level production of indigoidine. Considering the advantages of low-cost culture medium and simple culture conditions during the large-scale culture of Streptomyces, here, an updated regulation system derived from the Streptomyces self-sustaining system, constructed in our previous study, was established for the highly efficient production of indigoidine in Streptomyces lividans TK24. The updated system was constructed via promoter mining and σhrdB expression optimization, and this system was applied to precisely and continuously regulate the expression of indigoidine synthetase IndC derived from Streptomyces albus J1704. Finally, the engineered strain was cultured with cheap industrial glycerol as a supplementary carbon source, and 14.3 and 46.27 g/L indigoidine could be achieved in a flask and a 4 L fermentor, respectively, reaching the highest level of microbial synthesis of indigoidine. This study will lay a foundation for the industrial application of Streptomyces cell factories to produce indigoidine.

Mechanism of enhanced microalgal biomass and lipid accumulation through symbiosis between a highly succinic acid-producing strain of Escherichia coli SUC and Aurantiochytrium sp. SW1

Microalgae, known for rapid growth and lipid richness, hold potential in biofuels and high-value biomolecules. The symbiotic link with bacteria is crucial in large-scale open cultures. This study explores algal-bacterial interactions using a symbiotic model, evaluating acid-resistant Lactic acid bacteria (LAB), stress-resilient Bacillus subtilis and Bacillus licheniformis, and various Escherichia coli strains in the Aurantiochytrium sp. SW1 system. It was observed that E. coli SUC significantly enhanced the growth and lipid production of Aurantiochytrium sp. SW1 by increasing enzyme activity (NAD-IDH, NAD-ME, G6PDH) while maintaining sustained succinic acid release. Optimal co-culture conditions included temperature 28 °C, a 1:10 algae-to-bacteria ratio, and pH 8. Under these conditions, Aurantiochytrium sp. SW1 biomass increased 3.17-fold to 27.83 g/L, and total lipid content increased 2.63-fold to 4.87 g/L. These findings have implications for more efficient microalgal lipid production and large-scale cultivation.

Pseudomonas aphyarum sp. nov., Pseudomonas fontis sp. nov., Pseudomonas idahonensis sp. nov. and Pseudomonas rubra sp. nov., isolated from in, and around, a rainbow trout farm.

During a large-scale bacterial culturing effort of biofilms in the vicinity of a rainbow trout aquaculture facility in Idaho, USA, 10 isolates were identified as having pathogen-inhibiting activity and were characterized further. These isolates were shown to be Gram-negative, rod-shaped bacteria belonging to the genus Pseudomonas. Whole-genome comparisons and multi-locus sequence analysis using four housekeeping genes (16S rRNA, gyrA, rpoB and rpoD) showed that these 10 isolates clustered into four distinct species groups. These comparisons also indicated that these isolates were below the established species cutoffs for the genus Pseudomonas. Further phenotypic characterization using API 20NE, API ZYM and Biolog GENIII assays and chemotaxonomic analysis of cellular fatty acids were carried out. Based on the genomic, physiological and chemotaxonomic properties of these isolates, we concluded that these strains composed four novel species of the genus Pseudomonas. The proposed names are as follows: Pseudomonas aphyarum sp. nov. consisting of strains ID233, ID386T and ID387 with ID386T (=DSM 114641T=ATCC TSD-305T) as the type strain; Pseudomonas rubra sp. nov. consisting of strains ID291T, ID609 and ID1025 with ID291T (=DSM 114640T=ATCC TSD-303T) as the type strain; Pseudomonas idahonensis sp. nov. consisting of strains ID357T and ID1048 with ID357T (=DSM 114609T=ATCC TSD-304T) as the type strain; and Pseudomonas fontis sp. nov. consisting of strains ID656T and ID681 with ID656T (=DSM 114610T=ATCC TSD-306T) as the type strain.

Adventitious root culture of Lessertia frutescens for the production of triterpenoid saponins and polysaccharides

Lessertia frutescens is a perennial shrub of commercial importance in South Africa, but the scarcity of plant resources has limited current product production. In this study, to provide an alternative approach for obtaining L. frutescens material, adventitious roots (ARs) were induced from sterilized seedlings and cultured in a suspension culture system. During this process, selection tests were conducted to find a suitable auxin and its concentration for AR induction and a suitable basal medium for AR growth and metabolite accumulation; a kinetic study was then performed to constructure kinetic models. The results showed that compared to other auxins and concentrations, indole-3-butyric acid at 3 mg/L was suitable for increasing the number and length of ARs during AR induction. In AR suspension culture, Schenk and Hildebrandt (SH) was better than other basal media, and the maximum AR fresh (86.9 g/L) or dry weight (5.5 g/L), total triterpenoid saponin (92.6 mg/g DW), and polysaccharide (114.7 mg/g DW) contents were determined in the 1.5×SH medium. In addition, AR biomass and metabolite contents reached the maximum on day 42. The kinetic models for AR growth and triterpenoid and polysaccharide production were constructed, providing the basis for further optimization of culture conditions and large-scale culture.

Adsorption of l-lactate from cell culture media by layered double hydroxide and evaluation of its cytotoxicity to cell lines

The large-scale culture of human induced pluripotent stem cells (hiPSCs) is essential for developing new pharmaceuticals and regenerative therapy methods. While for the development of cultured meat products, mass production of animal myoblasts is necessary. Both hiPSCs and animal myoblasts consume d-glucose as their energy source and produce l-lactate, which accumulates in cell culture media and inhibits cell proliferation. To make large-scale cell culture economically feasible, l-lactate removal and subsequent reuse of media are of high importance. The adsorption technique is attractive for l-lactate removal due to its low cost, ease of operation, and scalability. The current study is dedicated to 4-(2-hydroxyethyl)-1-piperazineethanesulfonate (HEPES) intercalated Mg–Al layered double hydroxide (LDH), which acts as a biocompatible anion-exchanger in media. HEPES‧Mg–Al LDH was able to remove l-lactate from hiPS cells and myoblast-relevant media selectively while mostly retaining d-glucose. Adsorbent exhibited dose-dependent cytotoxicity to hiPSCs and C2C12 cells, mainly related to elevated osmolarity, HEPES, and Mg levels and adsorption of media micro components. By employing alternatively prepared sol-gel derived HEPES‧Mg–Al LDH, the required adsorbent dose for efficient l-lactate removal was reduced to a safe level. The current study thoroughly evaluates Mg–Al layered double hydroxides as suitable adsorbents for cell culture media regeneration and discusses the limitations of Mg–Al LDHs in systems relevant to hiPS cells and C2C12 cells. This work promotes the cost-effective large-scale production of cells and gives insight into the limitations of Mg–Al LDHs applied to systems of biological origin.

Systematic comparison of rAAV vectors manufactured using large-scale suspension cultures of Sf9 and HEK293 cells

Recombinant adeno-associated virus (rAAV) vectors could be manufactured by plasmid transfection into human embryonic kidney 293 (HEK293) cells or baculovirus infection of Spodoptera frugiperda (Sf9) insect cells. However, systematic comparisons between these systems using large-scale, high-quality AAV vectors are lacking. rAAV from Sf9 cells (Sf9-rAAV) at 2-50L and HEK293 cells (HEK-rAAV) at 2-200L scales were characterized. HEK-rAAV had ∼40-fold lower yields but ∼10-fold more host cell DNA measured by droplet digital PCR and next-generation sequencing, respectively. The electron microscope observed a lower full/empty capsid ratio in HEK-rAAV (70.8%) than Sf9-rAAV (93.2%), while dynamic light scattering and high-performance liquid chromatography analysis showed that HEK-rAAV had more aggregation. Liquid chromatography tandem mass spectrometry identified different post-translational modification profiles between Sf9-rAAV and HEK-rAAV. Furthermore, Sf9-rAAV had a higher tissue culture infectious dose/viral genome than HEK-rAAV, indicating better infectivity. Additionally, Sf9-rAAV achieved higher invitro transgene expression, as measured by ELISA. Finally, after intravitreal dosing into a mouse laser choroidal neovascularization model, Sf9-rAAV and HEK-rAAV achieved similar efficacy. Overall, this study detected notable differences in the physiochemical characteristics of HEK-rAAV and Sf9-rAAV. However, the invitro and invivo biological functions of the rAAV from these systems were highly comparable. Sf9-rAAV may be preferred over HEK293-rAAV for advantages in yields, full/empty ratio, scalability, and cost.

Understanding regulation in complex environments: a route to enhance photosynthetic light-reactions in microalgae photobioreactors

Microalgae are recognized as a sustainable source of biomass to produce a wide range of bioproducts. To maximize the positive environmental impact and achieve economic competitiveness of microalgae-based products, it is however still essential to improve the biomass productivity during large-scale cultivation. Microalgae large-scale cultures are generally limited by light availability and thus the efficiency in conversion of radiation energy into biomass is a major factor impacting productivity. Natural light is a highly variable environmental parameter, and it constantly changes following seasons, time of day, and weather conditions. The artificial environment of large-scale microalgae cultures generates a further layer of complexity added to these natural light dynamics. In fact, because of biomass density and cell self-shading, light is unevenly distributed in the mass culture. Moreover, because of mixing, cells move between different parts of the volume, generating abrupt fluctuations in light exposure. Although microalgae evolved various regulatory mechanisms to cope with dynamic light conditions, these are not adapted to respond to the complex mixture of natural and artificial fluctuations commonly encountered in large-scale cultures, often causing reduction in photosynthetic efficiency. In the past years, genetic approaches to improve the light reactions of photosynthesis have been explored to optimise the composition and regulation of the photosynthetic machinery to large-scale cultivation. These approaches have shown promising results at the laboratory scale but have yet to be fully proven at the industrial scale. This can be explained by the fact that the complexity of the cultivation environment on microalgae photosynthesis and its impact on productivity is underestimated. This work aims for a systematic discussion on the complex role played by the growth environment in determining microalgae photosynthetic performances upon cultivation at industrial scale, with the objective of maximizing the impact of genetic modifications and ultimately fully realize the potential of microalgae for biomass productivity.

Beneficial impact of multi-bacterial inoculation on growth of selected Brassicaceae seedlings in a greenhouse culture

Modern agriculture requires the development of new eco-friendly and cost efficient methods of crop production. In this study we tested if engineering Brassica microbiome by supplementation it with an inoculum composed of selected microorganisms can accelerate seedling growth and be a substitute for inorganic fertilizers. We hypothesised that the multiorganismal inoculum will be more efficient and affect a wide range of plants compared to inoculation with a single microorganism. We developed and examined several new multispecies inocula in the cultivation of different Brassica oleracea, B. rapa, Eruca sativa and Lactuca sativa cultivars. Every microorganism used for biotization was isolated from Arabidopsis arenosa (Brassicaceae) and tested for plant growth promoting properties. Of all the inocula tested, one (T4) containing only bacteria (Chryseobacterium lathyri, Bacillus cereus, Lysinibacillus fusiformis, Pseudomonas protegens) proved to be particularly efficient in increasing the fresh biomass of most B. oleracea and B. rapa cultivars cultured in the growth chamber. None of the bacteria used in the inoculum was able to activate plant growth individually. Thus, T4 inoculum was evaluated in a large-scale greenhouse culture of young Brassica vegetables. The results confirmed the positive effect of inoculation on the growth of selected Brassica crops, but it differed according to the plant genotype. What is more, the T4 inoculation proved to be as effective for increasing plant biomass as synthetic fertilizers. None of the inocula tested improved the growth of plants from genus other than Brassica.

Molecular characterization and expression of Megalobrama amblycephala (Wuchang bream) lysine monomethylase set7 and its potential role in hypoxia adaptation

Previously, we reported that the mammalian lysine monomethylase SET7 impairs the transcriptional activity of hypoxia-inducible factor (HIF), and set7-deficient zebrafish exhibit enhanced tolerance to hypoxia stress. Megalobrama amblycephala, an extensively farmed endemic species in China, is highly sensitive to hypoxia stress, which has posed a serious threat to its intensive and large-scale culture. Therefore, it is meaningful to identify key candidate genes related to the hypoxia tolerance trait in Megalobrama amblycephala. In this study, we found that set7 is highly conserved across species. The luciferase reporter assay showed that Megalobrama amblycephala set7 inhibits the transcriptional activity of hif-1αa/b and hif-2αa/b. Furthermore, using the fluorescent glucose analog 2-NBDG, we observed that overexpression of Megalobrama amblycephala set7 inhibited glucose uptake in EPC cells under hypoxic conditions. Our findings may provide clues to understand the function of Megalobrama amblycephala set7 in the hypoxia signaling pathway, and provide a potential target for genetic breeding of hypoxia tolerant species.