Production of secondary metabolites using tissue culture-based biotechnological applications.

Plants are the sources of many bioactive secondary metabolites which are present in plant organs including leaves, stems, roots, and flowers. Although they provide advantages to the plants in many cases, they are not necessary for metabolisms related to growth, development, and reproduction. They are specific to plant species and are precursor substances, which can be modified for generations of various compounds in different plant species. Secondary metabolites are used in many industries, including dye, food processing and cosmetic industries, and in agricultural control as well as being used as pharmaceutical raw materials by humans. For this reason, the demand is high; therefore, they are needed to be obtained in large volumes and the large productions can be achieved using biotechnological methods in addition to production, being done with classical methods. For this, plant biotechnology can be put in action through using different methods. The most important of these methods include tissue culture and gene transfer. The genetically modified plants are agriculturally more productive and are commercially more effective and are valuable tools for industrial and medical purposes as well as being the sources of many secondary metabolites of therapeutic importance. With plant tissue culture applications, which are also the first step in obtaining transgenic plants with having desirable characteristics, it is possible to produce specific secondary metabolites in large-scale through using whole plants or using specific tissues of these plants in laboratory conditions. Currently, many studies are going on this subject, and some of them receiving attention are found to be taken place in plant biotechnology and having promising applications. In this work, particularly benefits of secondary metabolites, and their productions through tissue culture-based biotechnological applications are discussed using literature with presence of current studies.

Tuning Compressive Young's Moduli and Antibacterial Activities of Alginate/Poly(N-isopropylacrylamide) Hydrogels with Laponite Layers and Cerium Ions.

Hybrid hydrogels containing alginate (Alg) and poly(N-isopropylacrylamide) (PNIPAAm) chains as natural and synthetic components, respectively, were crosslinked using double and triple pairs of the crosslinkers Ce3+/Ce4+, laponite (LP) RD, and N,N'-methylenebisacrylamide (BIS). (Alg/PNIPAAm)-Ce3+ and (Alg/PNIPAAm-PNIPAAm)-Ce3+ double- and triple-network structures were prepared using multivalent cerium ions (Ce3+), multifunctional laponite layers (L), and/or neutral tetrafunctonal BIS molecules (B). Compressive Young's moduli, E, were tuned by the type/concentration of crosslinkers and crosslinking procedures and the concentration of Alg chains. The antibacterial activity of positively charged ions and molecules is due to the electrostatic attraction with the negatively charged bacterial cell walls. In the current study, we report the antibacterial activity on Escherichia coli of Ce3+ ions in the absence and presence of gentamicin sulfate (GS) for double and triple networks. Nonbacterial areas, which are called inhibition zones, around the disks, and compressive E moduli of the single and double PNIPAAm and Alg/PNIPAAm networks crosslinked by LP RD and containing Ce3+/Ce4+ions in free and ionically bonded states, respectively, were higher than those of the ones crosslinked with BIS. Moreover, BIS- and LP RD-crosslinked single PNIPAAm hydrogels displayed larger inhibition zones than those of Alg/PNIPAAm hybrids, supporting the antibacterial activity of free Ce3+/Ce4+ ions diffused together with GS molecules. On the other hand, antibacterial activities of GS + Ce3+-loaded triple networks were much lower than those of their double counterparts because the increase in the structural complexity reduced the co-emission of antibacterial agents.

Improved mechanical properties of antimicrobial poly(N-[3-(dimethylaminopropyl)] methacrylamide) hydrogels prepared by free radical polymerization in the presence of cetyltrimethylammonium bromide as a lyotropic liquid crystal template.

The poor mechanical strength of the poly(N-[3-(dimethylamino)propyl] methacrylamide) (PDMAPMAAm) hydrogel limits its application as a drug delivery system and antimicrobial agent. In this study, both its morphology and antibacterial effectiveness were controlled through free radical solution polymerization in the presence of cetyltrimethylammonium bromide (CTAB; cationic nonreactive surfactant), forming lyotropic liquid crystal (LLC) mesophases. All the templated reactions proceeded in four different CTAB concentrations with three different concentrations of DMAPMAAm (2.0, 3.0 and 4.0 mol L-1), which were carried out in distilled-deionized water (DDW) using potassium persulfate (KPS) and N,N'-methylenebisacrylamide (BIS) as the initiator and crosslinker, respectively. The pH-dependent phase transition temperature (34 °C at pH 14), compression moduli, antibacterial and diffusion properties, and the effect of the LLC mesophases of CTAB on the hydrogel properties were investigated by mechanical measurements, image analysis, inhibition zone tests, X-ray diffractograms and polarized optical microscopy (POM). It was found that the compression moduli of the templated (T)-PDMAPMAAm hydrogels increased by nearly ten times (from ∼3.0 to 30.0 kPa) compared to that of the isotropic (I) ones. The POM and XRD results before the removal of CTAB exhibited the formation of lamellar and hexagonal mesophases. Further, the inhibition zones showed the ability of the I-PDMAPMAAm hydrogels to reduce the activity of E. coli even in the absence of CTAB, gentamicin (GS) and ciprofloxacin (CF). This was because the quaternary ammonium (QA) groups on the DMAPMAAm units could interact with the bacterial membrane.

Lemna minor, a hyperaccumulator shows elevated levels of Cd accumulation and genomic template stability in binary application of Cd and Ni: a physiological and genetic approach.

In this study, to determine whether having potential to be used as hyperaccumulator for Cd and Ni, numerous experiments were designed for conducting assessments for physiological and genotoxic changes along with defining possible alterations on mineral nutrient status of Lemna minor L. by applying Cd-Ni binary treatments (0, 100, 200 and 400 µM). Our study revealed that there were increases in the concentrations of B, Cr, Fe, K, Mg, and Mn whereas decreases were noticed in the concentrations of Na and Zn and the levels of Ca were inversely proportional to Cd-Ni applications showing tendency to increase at the low concentration and to decrease at the high concentration. Randomly Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR) analyses revealed that rather than band losses and new band formations, mostly intensity changes in the band profiles, and low polymorphism and high genomic template stability (GTS) were observed. Although, to date, L. minor was defined as an efficient hyperaccumulator/potential accumulator or competent phytoremedial agent by researchers. Our research revealed that L. minor showing high accumulation capability for Cd and having low polymorphism rate and high genomic template stability is a versatile hyperaccumulator, especially for Cd; therefore, highly recommended by us for decontamination of water polluted with Cd. NOVELTY STATEMENTMany studies have been focused on the effects of individual metal ions. However, heavy metal contaminants usually exist as their mixtures in natural aquatic environments. Especially, Cd and Ni coexist in industrial wastes.In this study, the accumulation properties of Lemna minor for both Cd and Ni were investigated and the effects of Cd and Ni on the bioaccumulation of B, Ca, Cu, Fe, Mg, K, Mn, Na, Pb and Zn in L. minor were also determined. This study furthermore aimed to assess the genotoxic effects of Cd and Ni found in being extended concentrations on DNA using the Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) method.

Effect of Mg doping on morphology, photocatalytic activity and related biological properties of Zn1-xMgxO nanoparticles.

The objective of this study is to synthesize ZnO and Mg doped ZnO (Zn1-xMgxO) nanoparticles via the sol-gel method, and characterize their structures and to investigate their biological properties such as antibacterial activity and hemolytic potential.Nanoparticles (NPs) were synthesized by the sol-gel method using zinc acetate dihydrate (Zn(CH3COO)2.2H2O) and magnesium acetate tetrahydrate (Mg(CH3COO)2.4H2O) as precursors. Methanol and monoethanolamine were used as solvent and sol stabilizer, respectively. Structural and morphological characterizations of Zn1-xMgxO nanoparticles were studied by using XRD and SEM-EDX, respectively. Photocatalytic activities of ZnO and selected Mg-doped ZnO (Zn1-xMgxO) nanoparticles were investigated by degradation of methylene blue (MeB). Results indicated that Mg doping (both 10% and 30%) to the ZnO nanoparticles enhanced the photocatalytic activity and a little amount of Zn0.90 Mg0.10 O photocatalyst (1.0 mg/mL) degraded MeB with 99% efficiency after 24 h of irradiation under ambient visible light. Antibacterial activity of nanoparticles versus Escherichia coli ( E. coli ) was determined by the standard plate count method. Hemolytic activities of the NPs were studied by hemolysis tests using human erythrocytes. XRD data proved that the average particle size of nanoparticles was around 30 nm. Moreover, the XRD results indicatedthat the patterns of Mg doped ZnO nanoparticles related to ZnO hexagonal wurtzite structure had no secondary phase for x ≤ 0.2 concentration. For 0 ≤ x ≤ 0.02, NPs showed a concentration dependent antibacterial activity against E. coli . While Zn0.90Mg0.10 O totally inhibited the growth of E. coli , upper and lower dopant concentrations did not show antibacterial activity.