Influence of plant growth regulators and salicylic acid on the production of some secondary metabolites in callus and cell suspension culture of Satureja sahendica Bornm.

<p class="042abstractstekst">The impact of combinations of plant growth regulators (PGRs) on callus culture of <em>Satureja sahendica </em>Bornm. was investigated. In nodal explants, the response of secondary metabolite production to different concentrations of PGRs was analyzed regarding the presence and absence of polyvinylpyrrolidone (PVP). The explants were cultured on MS media in presence of auxins (2,4-dichlorophenoxyacetic acid and naphthylacetic acid) and cytokinins (thidiazuron and kinetin); which were used in equal concentrations of 0.5, 1, and 2 mg l^-1. The treatment of 2 mg l^-1 2,4-D + 2 mg l^-1Kin (MD3) led to the highest production of total phenolics (4.303 ± 0.449 mg GAE g^-1) and flavonoids (24.903 ± 7.016 mg QE g^-1). Moreover, the effect of salicylic acid (SA) on the production of secondary metabolites in cell suspension culture of <em>Satureja sahendica</em> was evaluated. The cell suspension culture was established by culturing the nodal-derived friable callus in the liquid medium containing different concentrations of SA (0, 100, 150, 200 µM). An inverse relationship exists between the fresh mass and secondary metabolites contents. In addition, there was a significant difference among concentrations of SA in the production of total phenolics and flavonoid compounds. SA enhances secondary metabolites production and decreases cell fresh mass.</p>

Somatic Embryo Yield and Quality From Norway Spruce Embryogenic Tissue Proliferated in Suspension Culture

Somatic embryogenesis is being piloted for the commercial production of genetically improved Norway spruce (Picea abies L. Karst) forest regeneration material in Finland. The main challenge to making the process commercially relevant is the dependence on time-consuming and highly skilled manual labor. Automation and scaling up are needed to improve cost-effectiveness. Moving from the proliferation of embryogenic tissue on semisolid media to suspension cultures could improve process scalability. In a series of four experiments (overall, with 20 cell lines, 4–9 per experiment), the suitability of proliferation in suspension culture for Norway spruce somatic embryogenesis was evaluated based on the growth rate, indicators of stress conditions, good-quality cotyledonary embryo yield, and embling survival in a greenhouse. The proliferation rate in suspension was found equal to on semisolid media, but with a remarkable genotypic variation. Embryogenic tissue matured directly without pre-treatments from suspension onto semisolid media produced lower numbers of good-quality embryos than tissue matured from semisolid media. Rinsing the suspension-grown tissue with hormone-free liquid media before maturation improved embryo yield, bringing it closer to that of semisolid-grown tissue. Decreasing 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid concentrations in suspension proliferation media to 0.5 or 0.1 times those in semisolid media did not affect tissue growth and did not improve embryo production. The hydrogen peroxide (H2O2) content and guaiacol peroxidase activity were elevated in suspension cultures compared with semisolid medium, which had the same plant growth regulator content. In one experiment out of four, the greenhouse survival of germinants was lower when proliferation was carried out in full strength suspension than on semisolid media; in other experiments the survival rates were equal.

The Proliferation of Pre-Pubertal Porcine Spermatogonia in Stirred Suspension Bioreactors Is Partially Mediated by the Wnt/β-Catenin Pathway

Male survivors of childhood cancer are at risk of suffering from infertility in adulthood because of gonadotoxic chemotherapies. For adult men, sperm collection and preservation are routine procedures prior to treatment; however, this is not an option for pre-pubertal children. From young boys, a small biopsy may be taken before chemotherapy, and spermatogonia may be propagated in vitro for future transplantation to restore fertility. A robust system that allows for scalable expansion of spermatogonia within a controlled environment is therefore required. Stirred suspension culture has been applied to different types of stem cells but has so far not been explored for spermatogonia. Here, we report that pre-pubertal porcine spermatogonia proliferate more in bioreactor suspension culture, compared with static culture. Interestingly, oxygen tension provides an avenue to modulate spermatogonia status, with culture under 10% oxygen retaining a more undifferentiated state and reducing proliferation in comparison with the conventional approach of culturing under ambient oxygen levels. Spermatogonia grown in bioreactors upregulate the Wnt/ β-catenin pathway, which, along with enhanced gas and nutrient exchange observed in bioreactor culture, may synergistically account for higher spermatogonia proliferation. Therefore, stirred suspension bioreactors provide novel platforms to culture spermatogonia in a scalable manner and with minimal handling.

Engineering Considerations to Produce Bioactive Compounds from Plant Cell Suspension Culture in Bioreactors

The large-scale production of plant-derived secondary metabolites (PDSM) in bioreactors to meet the increasing demand for bioactive compounds for the treatment and prevention of degenerative diseases is nowadays considered an engineering challenge due to the large number of operational factors that need to be considered during their design and scale-up. The plant cell suspension culture (CSC) has presented numerous benefits over other technologies, such as the conventional whole-plant extraction, not only for avoiding the overexploitation of plant species, but also for achieving better yields and having excellent scaling-up attributes. The selection of the bioreactor configuration depends on intrinsic cell culture properties and engineering considerations related to the effect of operating conditions on thermodynamics, kinetics, and transport phenomena, which together are essential for accomplishing the large-scale production of PDSM. To this end, this review, firstly, provides a comprehensive appraisement of PDSM, essentially those with demonstrated importance and utilization in pharmaceutical industries. Then, special attention is given to PDSM obtained out of CSC. Finally, engineering aspects related to the bioreactor configuration for CSC stating the effect of the operating conditions on kinetics and transport phenomena and, hence, on the cell viability and production of PDSM are presented accordingly. The engineering analysis of the reviewed bioreactor configurations for CSC will pave the way for future research focused on their scaling up, to produce high value-added PDSM.

Rapid Start-Up of Anammox by Immobilization and Its Response to Low Temperature Stress

In view of the problems of slow start, easy loss and sensitive to low temperature environment in the suspension culture of anaerobic ammonia oxidation bacteria (AnAOB) suspension culture, polyvinyl alcohol (PVA) was used to prepare the anaerobic ammonia oxidation (anammox) immobilized filler, so as to realize the rapid start-up and activity improvement of anammox. Meanwhile, the response of nitrogen removal performance of encapsulated biomass to temperature reduction was determine by batch experiment. In addition, changes in the internal structure, flora composition and diversity of the filler were analyzed by scanning electron microscopy (SEM) and high-throughput sequencing. The results showed that the nitrogen removal capacity of the immobilized filler (E1) was significantly higher than that of the suspended sludge contrast system (S1) after 100d enrichment culture. The final nitrogen removal rate reached 1.168kg·(m3·d-1) -1, and the total nitrogen removal efficiency was 92%. The immobilization improved the resistance of AnAOB to low temperature. At 15°C, the effluent ammonia and nitrite of S1 were seriously accumulated, and E1 could maintain a stable nitrogen removal effect under the regulation of HRT. The population diversity was maintained in the immobilized filler, and the functional bacteria of anammox Candidatus Kuenenia was effectively enriched, accounting for 32.55% in E1. The results of this study provide valuable information for the application and popularization of anammox immobilized filler.