The associative induction of succinic acid and hydrogen sulfide for high-producing biomass, astaxanthin and lipids in Haematococcus pluvialis

To obtain higher yield of natural astaxanthin, the present study aims to develop a viable and economic induction strategy for astaxanthin production comprising succinic acid (SA) combined with sodium hydrosulfide (NaHS). The biomass (1.33 g L^-1), astaxanthin concentration (44.96 mg L^-1), astaxanthin content (163.55 pg cell^-1), and lipid content (55.34%) were achieved under 1.0 mM SA and 100 μM NaHS treatment. These results were concomitant with enhanced hydrogen sulfide (H₂S) but diminished reactive oxide species (ROS). Further study discovered that endogenous H₂S could improve astaxanthin and lipid coproduction under SA induction by mediating related gene transcript levels and ROS signalling. Additionally, the concentrations of biomass and astaxanthin increased to 2.14 g L^-1 and 66.25 mg L^-1, respectively, under the induction of SA and NaHS in a scaled-up bioreactor. Briefly, the work proposed a novel feasible strategy for high yields of biomass and astaxanthin by H. pluvialis.

Inducible manipulation of motor-cargo interaction using engineered kinesin motors

Molecular motors drive long-range intracellular transport of various vesicles and other cargoes within a cell. Identifying which kinesin motors interact with which type of transport vesicles has been challenging, especially in complex neuronal cells. Here, we present a highly adaptable toolbox of engineered kinesin motors to control and interrogate the selectivity and regulation of cargo transport with acute chemical induction. Selectivity of cargo-motor interaction can be addressed by systematic screening of a library of kinesin tails and neuronal cargoes. Additionally, our toolbox can be used to study kinesin-cargo regulatory mechanisms, and we found that cargo trafficking by KIF16B is regulated by its PX domain. Furthermore, our toolbox enables acute manipulation of polarized trafficking in living neurons by steering transport into axons or dendrites. Engineering kinesin motors provides a powerful tool to map the specificity of interactions between kinesin and cargoes, manipulate polarized transport and investigate cargo-motor interaction modes.

Mouse models of sarcopenia: classification and evaluation

Sarcopenia is a progressive and widespread skeletal muscle disease that is related to an increased possibility of adverse consequences such as falls, fractures, physical disabilities and death, and its risk increases with age. With the deepening of the understanding of sarcopenia, the disease has become a major clinical disease of the elderly and a key challenge of healthy ageing. However, the exact molecular mechanism of this disease is still unclear, and the selection of treatment strategies and the evaluation of its effect are not the same. Most importantly, the early symptoms of this disease are not obvious and are easy to ignore. In addition, the clinical manifestations of each patient are not exactly the same, which makes it difficult to effectively study the progression of sarcopenia. Therefore, it is necessary to develop and use animal models to understand the pathophysiology of sarcopenia and develop therapeutic strategies. This paper reviews the mouse models that can be used in the study of sarcopenia, including ageing models, genetically engineered models, hindlimb suspension models, chemical induction models, denervation models, and immobilization models; analyses their advantages and disadvantages and application scope; and finally summarizes the evaluation of sarcopenia in mouse models.

Impelling force and current challenges by chemicals in somatic cell reprogramming and expansion beyond hepatocytes

In the field of regenerative medicine, generating numerous transplantable functional cells in the laboratory setting on a large scale is a major challenge. However, the in vitro maintenance and expansion of terminally differentiated cells are challenging because of the lack of specific environmental and intercellular signal stimulations, markedly hindering their therapeutic application. Remarkably, the generation of stem/progenitor cells or functional cells with effective proliferative potential is markedly in demand for disease modeling, cell-based transplantation, and drug discovery. Despite the potent genetic manipulation of transcription factors, integration-free chemically defined approaches for the conversion of somatic cell fate have garnered considerable attention in recent years. This review aims to summarize the progress thus far and discuss the advantages, limitations, and challenges of the impact of full chemicals on the stepwise reprogramming of pluripotency, direct lineage conversion, and direct lineage expansion on somatic cells. Owing to the current chemical-mediated induction, reprogrammed pluripotent stem cells with reproducibility difficulties, and direct lineage converted cells with marked functional deficiency, it is imperative to generate the desired cell types directly by chemically inducing their potent proliferation ability through a lineage-committed progenitor state, while upholding the maturation and engraftment capacity posttransplantation in vivo. Together with the comprehensive understanding of the mechanism of chemical drives, as well as the elucidation of specificity and commonalities, the precise manipulation of the expansion for diverse functional cell types could broaden the available cell sources and enhance the cellular function for clinical application in future.

Prophasing interphase chromatin for assessing genetic damages-The evolution, applications and the future prospects

Premature chromosome condensation (PCC) involves induction of near-chromosome-like morphology to interphase chromatin. Experimental induction of PCC was achieved by somatic cell hybridization (SCH), an approach which evolved into a chemical-induction process. PCC presents most probably the only way in which cytogenetic assessment of damages can be analyzed in special situations such as availability of limited numbers of sample cells and for cells which have lost their ability to divide. Initial experiments on PCC were reported in late 1960s and the technique has evolved into one with wide range of applications owing to its increased efficiency in detecting primary DNA damages. Biodosimetry remains as the primary area which utilizes PCC technique to the maximum efficiency with several multiple-groups participating in collaborative exercises for biodosimetric applications. However, in spite of the advantages that the technique offers, it is yet to reach its full potential. This is due to the inherent limitations of the manner in which PCC is induced currently; by the somatic cell hybridization and chemical-induction processes. An approach which combines these two would sure help in taking PCC to its highest potential as the preferred technique for assessment of primary DNA damages. We present the chronological events of evolution of the PCC technique along with its applications. Also, the limitations of the technique along with the suggestions for further refinement of the PCC technique are discussed.

Effects of a NTG-based chemical mutagenesis on the propamocarb-tolerance of the nematophagous fungus Lecanicillium attenuatum

Lecanicillium attenuatum is an important nematophagous fungus with potential as a biopesticide for control of plant-pathogenic nematodes. However, relatively low fungicide-tolerance limits its application in the field. To improve the propamocarb-tolerance of L. attenuatum, a NTG-based mutagenesis system was established. Among different combinations of NTG concentration and treatment time in the first-round NTG treatment, the treatment of 1.0mg/ml NTG for 60min gave a proper conidial lethality rate of 84.6% and the highest positive mutation rate of 7.7%, and then produced the highest propamocarb-tolerant mutant LA-C-R1-T4-M whose EC₅₀ value reached to 1050.0μg/ml. The positive mutation range was 105.1% in the first-round NTG treatment. Multiple-round NTG treatment was further employed to enhance the propamocarb tolerance of L. attenuatum. The positive mutation range was significantly accumulated to 179.3% on the third-round NTG treatment, and then appeared to level-off and remained constant. These results indicated that multiple-round NTG treatment had a significant accumulative effect on fungal tolerance to propamocarb. Among all chemical-mutants, the LA-C-R3-M was the highest tolerant to propamocarb, whose EC₅₀ value was increased 2.79-fold compared to the wild-type strain, and it was mitotic stable after 20 passages on PDA medium. Colony growth, conidia yield and conidial germination on plates, and parasitism of nematode eggs of M. incognita and H. glycines were not significantly changed by the NTG-based mutagenesis compared to the wild-type strain in either single- or multiple-round NTG treatment. In conclusion, we succeeded in improving the propamocarb tolerance of L. attenuatum via the optimized NTG-based mutagenesis system. The improved strain LA-C-R3-M could be potentially applied with propamocarb in the field.

"Neuronal-Like Differentiation of Murine Mesenchymal Stem Cell Line: Stimulation by Juglans regia L. Oil"

Mesenchymal stem cells have been extensively used for cell-based therapies especially in neuronal diseases. Studies still continue to delineate mechanisms involved in differentiating mesenchymal stem cells into neuronal cells under experimental conditions as they have low mortality rate and hence, the number of cells available for experiments is much more limited. Culturing and differentiating of neuronal cell is more challenging as they do not undergo cell division thus, bringing them to differentiate proves to be a difficult task. Here, the aim of this study is to investigate whether Juglans regia L. (walnut oil) differentiates multipotent, C3H10T1/2 cells, a murine mesenchymal stem cell line, into neuronal cells. A simple treatment protocol induced C3H10T1/2 cells to exhibit a neuronal phenotype. With this optimal differentiation protocol, almost all cells exhibited neuronal morphology. The cell bodies extended long processes. C3H10T1/2 cells were plated and treated with walnut oil post 24 h of plating. The treatment was given (with walnut oil treated cultures with or without control cultures) at different concentrations. The cultured cells were then stained with cresyl violet acetate solution which was used to stain the Nissl substance in the cytoplasm of the induced neuronal culture. The results indicated that the C3H10T1/2 cells differentiated into neuronal-like cells with long outgrowths of axon-like structures able to take up the cresyl violet acetate stain indicating their preliminary differentiation into neuronal-like morphology with walnut oil treatment. Treating the mesenchymal stem cells can in future establish a cultured mesenchymal stem cell line as neuronal differentiating cell line model.