Transcriptome sequencing and metabolite profiling analyses provide comprehensive insight into molecular mechanisms of flower development in Dendrobium officinale (Orchidaceae)

Plant Molecular Biology - This research provides comprehensive insight into the molecular networks and molecular mechanisms underlying D. officinale flower development. Flowers are complex...     

Correction to: NaCl-induced stress: physiological responses of six halophyte species in in vitro and in vivo culture

Plant Cell, Tissue and Organ Culture (PCTOC) - In the original article, some of the values in the fifth column of Table 2 and in the fifth and eighth columns of Table 4 are incorrect. The corrected...     

Effect of Pulsed Electromagnetic Fields on Human Mesenchymal Stem Cells Using 3D Magnetic Scaffolds

Alternative bone regeneration strategies that do not rely on harvested tissue or exogenous growth factors are needed. One of the major challenges in tissue reconstruction is recreating the bone tissue microenvironment using the appropriate combination of cells, scaffold, and stimulation to direct differentiation. This study presents a bone regeneration formulation that involves the use of human adipose-derived mesenchymal stem cells (hASCs) and a three-dimensional (3D) hydrogel scaffold based on self-assembled RADA16 peptides containing superparamagnetic iron oxide nanoparticles (NPs). Although superparamagnetic NPs could be used as stimulus to manipulate the cell proliferation and differentiation, in this paper their use is explored for assisting osteogenic differentiation of hASCs in conjunction with direct stimulation by extremely low-frequency pulsed electromagnetic fields (pEMFs). Cellular morphology, proliferation, and viability, as well as alkaline phosphatase activity, calcium deposition, and osteogenic capacity were monitored for cells cultured up to 21 days in the 3D construct. The results show that the pEMFs and NPs do not have any negative effect on cell viability, but instead distinctly induced early differentiation of hASCs to an osteoblastic phenotype, when compared with cells without biophysical stimulation. This effect is attributed to synergy between the pEMFs and NPs, which may have stimulated mechanotransduction pathways, which, in turn activated biochemical signals between cells to differentiate or proliferate. This approach may offer a safe and effective option for the treatment of non-union bone fractures. Bioelectromagnetics. © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc.     

Response of in vitro strawberry to antibiotics

By identifying antibiotics that had the least phytotoxic effects on explants during genetic transformation, we evaluated the effect of various antibiotics on callus induction and morphogenesis from leaf explants and in vitro growth of Fragaria × ananassa Duch. cv. Toyonaka. Results showed that kanamycin (Kan) significantly inhibited callus induction, bud differentiation and root morphogenesis while carbenicillin (Carb), cefotaxime (Cef) and an equal concentration of Cef and Carb up to 500 mg L⁻¹ had no significant effects on callus induction and shoot growth. Kan, even at 2.5 mg L⁻¹, significantly inhibited callus induction, shoot regeneration and root formation, while no shoots regenerated at concentrations above 15 mg L⁻¹. Rooting was completely inhibited in the presence of 50 mg L⁻¹ Kan. Cef had negative effects on shoot regeneration from leaf explants and in vitro growth of strawberry. Compared to Cef, Carb at ≤300 mg L⁻¹ significantly promoted shoot and root organogenesis. However, an equal concentration of Carb plus Cef could alleviate the negative effect of Cef on strawberry. Results from relative electrolyte leakage, root and antioxidant activities, O₂^·− production rate, H₂O₂, proline and MDA contents showed that Kan, Cef and Carb caused electrolyte leakage and triggered active enzymatic processes and metabolism. This offers a possible mechanism for the inhibition or stimulation of strawberry growth caused by these antibiotics.     

Structural change in wood by brown rot fungi and effect on enzymatic hydrolysis

The effects of biological pretreatment on Pinus radiata and Eucalyptus globulus, were evaluated after exposure to two brown rot fungi Gloephylum trabeum and Laetoporeus sulphureus. Changes in chemical composition, structural modification, and susceptibility to enzymatic hydrolysis in the degraded wood were analyzed. After eight weeks of biodegradation, the greatest loss of weight and hemicellulose were 13% and 31%, respectively, for P. radiata with G. trabeum. The content of glucan decreased slightly, being the highest loss of 20% for E. globulus with G. trabeum. Consistent with degradation mechanism of these fungi, lignin was essentially undegraded by both brown rot fungi. Both brown rot fungi cause a sharp reduction in the cellulose degree of polymerization (DP) in the range between 58% and 79%. G. trabeum depolymerized cellulose in both wood faster than L. sulphureus. Also, structural characteristic of crystalline cellulose were measured by using two different techniques - X-ray diffraction (XRD) and infrared spectroscopy (FT-IR). The biological pretreatments showed an effect on cellulose crystallinity structure, a decrease between 6% and 21% was obtained in the crystallinity index (CrI) calculated by IR, no changes were observed in the XRD. Material digestibility was evaluated by enzymatic hydrolysis, the conversion of cellulose to glucose increased with the biotreatment time. The highest enzymatic hydrolysis yields were obtained when saccharification was performed on wood biopretreated with G. trabeum (14% P. radiata and 13% E. globulus). Decreasing in DP and CrI, and hemicellulose removal result in an increase of enzymatic hydrolysis performance. Digestibility was better related to DP than with other properties. G. trabeum can be considered as a potential fungus for biological pretreatment, since it provides an effective process in breaking the wood structure, making it potentially useful in the development of combined pretreatments (biological-chemical). A viable alternative to pretreatment process that can be used is a bio-mimetic system, similar to low-molecular complexes generated by fungi such as G. trabeum combined pretreatments (biological-chemical).     

Action of xylan deacetylating enzymes on monoacetyl derivatives of 4-nitrophenyl glycosides of β-D-xylopyranose and α-L-arabinofuranose

Measurements of esterase activity by enzyme-coupled assays on monoacetates of 4-nitrophenyl β-d-xylopyranoside and 4-nitrophenyl α-l-arabinofuranoside showed that acetylxylan esterases of families 1, 4 and 5 produced by Trichoderma reesei and Penicillium purpurogenum have a strong preference for deacetylation of position 2 in xylopyranosides. The acetylxylan esterases exhibit only weak activity on acetylated arabinofuranosides, with 2-acetate as the best substrate. Acetyl esterases of family 16 produced by the same two fungi deacetylate in xylopyranosides preferentially positions 3 and 4. Their specific activity on arabinofuranosides is also much lower than on xylopyranosides, however, substantially greater than that in the case of typical acetylxylan esterases.