Showing papers in "Biotechnology Letters in 2017"

Microbial and genetically engineered oils as replacements for fish oil in aquaculture feeds

Abstract: As the global population grows more of our fish and seafood are being farmed. Fish are the main dietary source of the omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, but these cannot be produced in sufficient quantities as are now required for human health. Farmed fish have traditionally been fed a diet consisting of fishmeal and fish oil, rich in n-3 LC-PUFA. However, the increase in global aquaculture production has resulted in these finite and limited marine ingredients being replaced with sustainable alternatives of terrestrial origin that are devoid of n-3 LC-PUFA. Consequently, the nutritional value of the final product has been partially compromised with EPA and DHA levels both falling. Recent calls from the salmon industry for new sources of n-3 LC-PUFA have received significant commercial interest. Thus, this review explores the technologies being applied to produce de novo n-3 LC-PUFA sources, namely microalgae and genetically engineered oilseed crops, and how they may be used in aquafeeds to ensure that farmed fish remain a healthy component of the human diet.

Inhibitory effect of flavonoids against NS2B-NS3 protease of ZIKA virus and their structure activity relationship.

Abstract: To determine the inhibitory activities of flavonoids against NS2B-NS3 protease of ZIKA virus (ZIKV NS2B-NS3pro) expressed in Escherichia coli BL21 (DE3) and their structure activity relationship. ZIKV NS2B-NS3pro was expressed in E. coli BL21(DE3) as a 35 kDa protein. It had a K m of 26 µM with the fluorogenic peptide Dabcyl-KTSAVLQSGFRKME-Edan. The purified ZIKV NS2B-NS3pro was used for inhibition and kinetic assays to determine the activities of 22 polyphenol compounds. These polyphenol compounds at 100 µM inhibited the activity of ZIKV NS2B-NS3pro by 6.2–88%. Seven polyphenol compounds had IC50 ranging from 22 ± 0.2 to 112 ± 5.5 µM. Myricetin showed a mixed type inhibitory pattern against ZIKV NS2B-NS3pro protease. Its IC50 value was 22 ± 0.2 µM with a K i value of 8.9 ± 1.9 µM. The chemical structure of a polyphenol compound and its inhibitory activity against ZIKV NS2B-NS3pro can be explored to develop highly selective inhibitors against ZIKV NS2B-NS3pro.

miRNAs: Major modulators for crop growth and development under abiotic stresses.

Abstract: Cumulatively, biotic and abiotic stresses of various magnitudes can decrease the production of crops by 70%. miRNAs have emerged as a genetic tool with enormous potential that can be exploited to understand stress tolerance at the molecular level and eventually regulate stress in crops. Plant miRNA targets frequently fit into diverse families of TFs that control the expression of genes related to a certain trait. As key machinery in gene regulatory networks, it is agreed that a broad understanding of miRNAs will greatly increase our understanding of plant responses to environmental stresses. miRNA-led stress regulatory networks are being considered as novel tools for the development of abiotic stress tolerance in crops. At this time, we need to expand our knowledge about the modulatory role of miRNAs during environmental fluctuations. It has become exceedingly clear that with increased understanding of the role of miRNAs during stress, the techniques for using miRNA-mediated gene regulation to enhance plant stress tolerance will become more effective and reliable. In this review we present: (1) miRNAs as a potential avenue for the modulation of abiotic stresses, and (2) summarize the research progress regarding plant responses to stress. Current progress is explained through discussion of the identification and validation of several miRNAs that enhance crop tolerance of salinity, drought, etc., while missing links on different aspects of miRNAs related to abiotic stress tolerance are noted.

Autophagy regulated by lncRNA HOTAIR contributes to the cisplatin-induced resistance in endometrial cancer cells.

Abstract: To identify whether lncRNAs (long non-coding RNA) participate in the regulation of cisplatin-resistant induced autophagy in endometrial cancer cells. Autophagy activity was significantly boosted in cisplatin-resistant Ishikawa cells, a human endometrial cancer cell line, compared with that in parental Ishikawa cells. After analyzing the overall long noncoding RNA (lncRNA) profiling, a meaningful lncRNA, HOTAIR, was identified. It was down-regulated simultaneously in cisplatin-resistant Ishikawa cells and parental Ishikawa cells treated with cisplatin. RNA interference of HOTAIR reduced the proliferation of cisplatin-resistant Ishikawa cells and enhanced the autophagy activity of cisplatin-resistant Ishikawa cells with or without cisplatin treatment, in addition, beclin-1, multidrug resistance (MDR), and P-glycoprotein (P-gp) were mediated by lncRNA HOTAIR. It is clear that lncRNAs, specifically HOTAIR, can regulate the cisplatin-resistance ability of human endometrial cancer cells through the regulation of autophagy by influencing Beclin-1, MDR, and P-gp expression.

Progress in biocatalysis with immobilized viable whole cells: systems development, reaction engineering and applications

Abstract: Viable microbial cells are important biocatalysts in the production of fine chemicals and biofuels, in environmental applications and also in emerging applications such as biosensors or medicine. Their increasing significance is driven mainly by the intensive development of high performance recombinant strains supplying multienzyme cascade reaction pathways, and by advances in preservation of the native state and stability of whole-cell biocatalysts throughout their application. In many cases, the stability and performance of whole-cell biocatalysts can be highly improved by controlled immobilization techniques. This review summarizes the current progress in the development of immobilized whole-cell biocatalysts, the immobilization methods as well as in the bioreaction engineering aspects and economical aspects of their biocatalytic applications.

miR-34a attenuates glioma cells progression and chemoresistance via targeting PD-L1

Abstract: To investigate the roles of miR-34a in progression and chemoresistance of glioma cells. Quantitative real-time PCR analysis showed that miR-34a level was lower, but PD-L1 expression level was higher in glioma tissue specimens compared with normal brain tissues and their expression levels were negatively correlated. Ectopic expression of miR-34a inhibited glioma cell proliferation, promoted cell cycle arrest in G1/S phase and cell apoptosis. Additionally, miR-34a/PD-L1 axis was again confirmed and co-expression of PD-L1 with miR-34a mimics attenuated the effects of miR-34a on cell proliferation and apoptosis in glioma cells. Importantly, PD-L1 overexpression resulted in chemoresistance in glioma cells, this effect was attenuated by miR-34a overexpression. miR-34a inhibits glioma cells progression and chemoresistance via targeting PD-L1.

Bioprinting technologies for disease modeling.

Abstract: There is a great need for the development of biomimetic human tissue models that allow elucidation of the pathophysiological conditions involved in disease initiation and progression Conventional two-dimensional (2D) in vitro assays and animal models have been unable to fully recapitulate the critical characteristics of human physiology Alternatively, three-dimensional (3D) tissue models are often developed in a low-throughput manner and lack crucial native-like architecture The recent emergence of bioprinting technologies has enabled creating 3D tissue models that address the critical challenges of conventional in vitro assays through the development of custom bioinks and patient derived cells coupled with well-defined arrangements of biomaterials Here, we provide an overview on the technological aspects of 3D bioprinting technique and discuss how the development of bioprinted tissue models have propelled our understanding of diseases' characteristics (ie initiation and progression) The future perspectives on the use of bioprinted 3D tissue models for drug discovery application are also highlighted

Current advances in biological production of propionic acid

Abstract: Propionic acid and its derivatives are considered "Generally Recognized As Safe" food additives and are generally used as an anti-microbial and anti-inflammatory agent, herbicide, and artificial flavor in diverse industrial applications. It is produced via biological pathways using Propionibacterium and some anaerobic bacteria. However, its commercial chemical synthesis from the petroleum-based feedstock is the conventional production process bit results in some environmental issues. Novel biological approaches using microorganisms and renewable biomass have attracted considerable recent attention due to economic advantages as well as great adaptation with the green technology. This review provides a comprehensive overview of important biotechnological aspects of propionic acid production using recent technologies such as employment of co-culture, genetic and metabolic engineering, immobilization technique and efficient bioreactor systems.

New approaches to antibiotic discovery.

Abstract: New antibiotics are urgently required by human medicine as pathogens emerge with developed resistance to almost all antibiotic classes. Pioneering approaches, methodologies and technologies have facilitated a new era in antimicrobial discovery. Innovative culturing techniques such as iChip and co-culturing methods which use 'helper' strains to produce bioactive molecules have had notable success. Exploiting antibiotic resistance to identify antibacterial producers performed in tandem with diagnostic PCR based identification approaches has identified novel candidates. Employing powerful metagenomic mining and metabolomic tools has identified the antibiotic'ome, highlighting new antibiotics from underexplored environments and silent gene clusters enabling researchers to mine for scaffolds with both a novel mechanism of action and also few clinically established resistance determinants. Modern biotechnological approaches are delivering but will require support from government initiatives together with changes in regulation to pave the way for valuable, efficacious, highly targeted, pathogen specific antimicrobial therapies.

Metabolic pathways for lipid synthesis under nitrogen stress in Chlamydomonas and Nannochloropsis.

Abstract: Microalgae are currently being considered as a clean, sustainable and renewable energy source. Enzymes that catalyse the metabolic pathways for biofuel production are specific and require strict regulation and co-ordination. Thorough knowledge of these key enzymes along with their regulatory molecules is essential to enable rational metabolic engineering, to drive the metabolic flux towards the desired metabolites of importance. This paper reviews two key enzymes that play their role in production of bio-oil: DGAT (acyl–CoA:diacylglycerol acyltransferase) and PDAT (phospholipid:diacylglycerol acyltransferase). It also deals with the transcription factors that control the enzymes while cell undergoes a metabolic shift under stress. The paper also discusses the association of other enzymes and pathways that provide substrates and precursors for oil accumulation. Finally a futuristic solution has been proposed about a synthetic algal cell platform that would be committed towards biofuel synthesis.

Pharmacological and pharmacokinetic properties of lanthipeptides undergoing clinical studies.

Abstract: The intrinsic qualities of lanthipeptides for their use as therapeutic drugs present several challenges because of their properties, which include stability, solubility and bioavailability, which, under physiological conditions, are very low. Researches have encouraged clinical evaluation of a few compounds, such as mutacin 1140, microbisporicin, actagardine and duramycin, with pharmacokinetic profiles showing rapid distribution and elimination rates, good bioavailability and fecal excretion, as well as high protein binding. Local and parenteral administration are currently suitable to minimize environmental influences on lanthipeptides and ensure efficient activity. Nevertheless, valuable improvements on pharmacodynamic and pharmacokinetic properties may also permit systemic applications via enteral routes. Understanding how rational modifications influence the desired pharmacological and pharmacokinetic properties of these biomolecules would help to answer some specific questions about their susceptibility to environmental changes, mechanism of action and how to engineer other peptides of the same group to improve their clinical relevance.

Basic leucine zipper domain transcription factors: the vanguards in plant immunity.

Abstract: Regulation of spatio-temporal expression patterns of stress tolerance associated plant genes is an essential component of the stress responses. Eukaryotes assign a large amount of their genome to transcription with multiple transcription factors (TFs). Often, these transcription factors fit into outsized gene groups which, in several cases, exclusively belong to plants. Basic leucine zipper domain (bZIP) transcription factors regulate vital processes in plants and animals. In plants, bZIPs are implicated in numerous fundamental processes like seed development, energy balance, and responses to abiotic or biotic stresses. Systematic analysis of the information obtained over the last two decades disclosed a constitutive role of bZIPs against biotic stress. bZIP TFs are vital players in plant innate immunity due to their ability to regulate genes associated with PAMP-triggered immunity, effector-triggered immunity, and hormonal signaling networks. Expression analysis of studied bZIP genes suggests that exploration and functional characterization of novel bZIP TFs in planta is helpful in improving crop resistance against pathogens and environmental stresses. Our review focuses on major advancements in bZIP TFs and plant responses against different pathogens. The integration of genomics information with the functional studies provides new insights into the regulation of plant defense mechanisms and engineering crops with improved resistance to invading pathogens. Conclusively, succinct functions of bZIPs as positive or negative regulator mediate resistance to the plant pathogens and lay a foundation for understanding associated genes and TFs regulating different pathways. Moreover, bZIP TFs may offer a comprehensive transgenic gizmo for engineering disease resistance in plant breeding programs.

Antioxidant properties of mesenchymal stem cells against oxidative stress in a murine model of colitis

Abstract: To investigate the effects of oxidative stress injury in dextran sulfate sodium (DSS)-induced colitis in mice treated with mesenchymal stem cells (MSC). Mice exposed to oral administration of 2% DSS over 7 days presented a high disease activity index and an intense colonic inflammation. Systemic infusion of MSC protected from severe colitis, reducing weight loss and diarrhea while lowering the infiltration of inflammatory cells. Moreover, toxic colitis injury increased oxidative stress. Administration of DSS decreased reduced glutathione (GSH) and superoxide dismutase (SOD) activity, and increased thiobarbituric acid-reactive substances levels in the colon. No alteration was found in catalase (CAT) and glutathione peroxidase (GPx) activity. Otherwise, MSC transplantation was able to prevent the decrease of GSH levels and SOD activity suggestive of an antioxidant property of MSC. The oxidative stress is a pathomechanism underlying the pathophysiology of colitis and MSC play an important role in preventing the impairment of antioxidants defenses in inflamed colon.

Haloarchaea: worth exploring for their biotechnological potential.

Abstract: Halophilic archaea are unique microorganisms adapted to survive under high salt conditions and biomolecules produced by them may possess unusual properties. Haloarchaeal metabolites are stable at high salt and temperature conditions that are useful for industrial applications. Proteins and enzymes of this group of archaea are functional under salt concentrations at which bacterial counterparts fail to be active. Such properties makes haloarchaeal enzymes suitable for salt-based applications and their use under dehydrating conditions. For example, bacteriorhodopsin or the purple membrane protein present in halophilic archaea has the most recognizable applications in photoelectric devices, artificial retinas, holograms etc. Haloarchaea are also useful for bioremediation of polluted hypersaline areas. Polyhydroxyalkanoates and exopolysccharides produced by these microorganisms are biodegradable and have the potential to replace commercial non-degradable plastics and polymers. Moreover, halophilic archaea have excellent potential to be used as drug delivery systems and for nanobiotechnology by virtue of their gas vesicles and S-layer glycoproteins. Despite of possible applications of halophilic archaea, laboratory-to-industrial transition of these potential candidates is yet to be established.

miR-93 enhances hepatocellular carcinoma invasion and metastasis by EMT via targeting PDCD4.

Abstract: To clarify the potential biological function of miR-93 and its related molecular mechanism underlying metastasis in human hepatocellular carcinoma (HCC). miR-93 was significantly up-regulated in HCC tissues and was associated with poor 5-year overall survival in HCC patients. Transwell assays showed that over-expression of miR-93 increased HCC cell migration and invasion in vitro. Programmed cell death 4 (PDCD4) was a target gene of miR-93 and miR-93 could down-regulate the expression of PDCD4 by directly targeting its 3′-UTR. The re-expression of PDCD4 could attenuate the HCC cell invasion and migration induced by miR-93, while the knockdown of PDCD4 would promote HCC cell migration and invasion via the epithelial-mesenchymal transition (EMT) pathway. miR-93 provides new insight into the molecular mechanisms of pathogenesis and progression in HCC and offer a potential therapeutic target for the treatment of HCC patients.

Technical difficulties and solutions of direct transesterification process of microbial oil for biodiesel synthesis

Abstract: Microbial oils are considered as alternative to vegetable oils or animal fats as biodiesel feedstock. Microalgae and oleaginous yeast are the main candidates of microbial oil producers’ community. However, biodiesel synthesis from these sources is associated with high cost and process complexity. The traditional transesterification method includes several steps such as biomass drying, cell disruption, oil extraction and solvent recovery. Therefore, direct transesterification or in situ transesterification, which combines all the steps in a single reactor, has been suggested to make the process cost effective. Nevertheless, the process is not applicable for large-scale biodiesel production having some difficulties such as high water content of biomass that makes the reaction rate slower and hurdles of cell disruption makes the efficiency of oil extraction lower. Additionally, it requires high heating energy in the solvent extraction and recovery stage. To resolve these difficulties, this review suggests the application of antimicrobial peptides and high electric fields to foster the microbial cell wall disruption.

A reductase gene mppE controls yellow component production in azaphilone polyketide pathway of Monascus

Abstract: To characterize a biosynthetic gene that is selectively involved in the biosynthesis of yellow or orange components in the azaphilone polyketide pathway of Monascus. A reductive modification is predicted to control the relative levels of reduced (yellow) and oxidized (orange and red) components in the pathway of azaphilone pigment biosynthesis in Monascus. Targeted inactivation of a reductase gene mppE enhanced orange and red pigment production whereas overexpression of the gene promoted yellow pigment production. The effect of mppE overexpression was dependent on culture methods, and augmented yellow pigmentation was evident in a submerged culture employing a chemically defined medium. MppE controls the biosynthesis of the yellow pigments, ankaflavin and monascin, as a reductive enzyme in the azaphilone polyketide pathway.

MiRNA-145 suppresses lung adenocarcinoma cell invasion and migration by targeting N-cadherin

Abstract: To investigate the roles of miR-145 in lung adenocarcinoma (LAC) and to clarify the regulation of N-cadherin by miR-145. In 57 paired clinical LAC tissues, diminished miR-145 was significantly correlated with the lymph node metastasis and was negatively correlated with N-cadherin mRNA level expression. Wound healing and transwell assays revealed a reduced capability of tumor metastasis induced by miR-145 in LAC. miR-145 negatively regulated the invasion of cell lines through targeting N-cadherin by directly binding to its 3′-untranslated region. Silencing of N-cadherin inhibited invasion and migration of LAC cell lines similar to miR-145 overexpression. MiR-145 could inhibit invasion and migration of lung adenocarcinoma cell lines by directly targeting N-cadherin.

Application of chitooligosaccharides as antioxidants in beer to improve the flavour stability by protecting against beer staling during storage.

Abstract: To improve beer flavour stability by adding chitooligosaccharides that prevent formation of staling compounds and also scavenge radicals in stale beer Chitooligosaccharides, at 0001–001%, inhibited the formation of staling compounds in forced aged beer The formation of 5-hydroxymethylfurfural, trans-2-nonenal and phenylacetaldehyde were decreased by 105, 360 and 27%, respectively, when compared with those in stale beer without chitooligosaccharide addition The capability of chitooligosaccharides to prevent staling compound formation depended on their molecular size (2 or 3 kDa) The DPPH/hydroxyl radical scavenging activity in fresh beer significantly lower than that in forced aged beer in the presence of chitooligosaccharides When compared with stale beer without added chitooligosaccharides, the radical scavenging activity could be increased by adding chitooligosaccharides to forced aged beer Chitooligosaccharides play an active part in the prevention of beer flavour deterioration by inhibiting the formation of staling compounds and increasing radical scavenging activity

Proteomic approach to address low seed germination in Cyclobalnopsis gilva.

Abstract: Seeds play essential roles in plant life cycle and germination is a complex process which is associated with different phases of water imbibition. Upon imbibition, seeds begin utilization of storage substances coupled with metabolic activity and biosynthesis of new proteins. Regeneration of organelles and emergence of radicals lead to the establishment of seedlings. All these activities are regulated in coordinated manners. Translation is the requirement of germination of seeds via involvements of several proteins like beta-amylase, starch phosphorylase. Some important proteins involved in seed germination are discussed in this review. In the past decade, several proteomic studies regarding seed germination of various species such as rice, Arabidopsis have been conducted. We face A paucity of proteomic data with respect to woody plants e.g. Fagus, Pheonix etc. With particular reference to Cyclobalnopsis gilva, a woody plant having low seed germination rate, no proteomic studies have been conducted. The review aims to reveal the complex seed germination mechanisms from woody and herbaceous plants that will help in understanding different seed germination phases and the involved proteins in C. gilva.

Bilirubin enzyme biosensor: potentiality and recent advances towards clinical bioanalysis

Abstract: Bilirubin detection plays a major role in healthcare. Its high concentration in human serum is lethal and must be determined accurately. Clinically, it is vital for assessing patients with deleterious health conditions such as jaundice or icterus, hepatitis, mental disorders, cerebral palsy and brain damage especially in the case of neonates. In evaluating the drawbacks regarding the conventional methodology of bilirubin detection, there is need for a superior analytical tool. Bilirubin oxidase (BOx)-based sensors have been designed for the ultrasensitive analysis of bilirubin and quality deliverance of treatment and this review highlights the different mechanisms of bilirubin detection using different modified electrodes. Further, it also addresses the exploitation of highly attractive electrocatalytic properties of elite nanoparticles such as gold and zirconia- coated silica nanoparticles in enhancing the reproducibility and specificity of bilirubin biosensors.

Production of β-carotene by expressing a heterologous multifunctional carotene synthase in Yarrowia lipolytica.

Abstract: To obtain functional expression of a heterologous multifunctional carotene synthase containing phytoene synthase, phytoene dehydrogenase, and lycopene β-cyclase activities encoded by carS from Schizochytrium sp. in order to allow Yarrowia lipolytica to produce β-carotene. To increase the integration efficiency of a 3.8 kb carS under the control of P GPD promoter with a 2 kb selection marker, ura3, along with a geranylgeranyl diphosphate synthase (GGS1) expression cassette (~10 kb in total), was inserted into the Y. lipolytica chromosome, and the DNA assembler method was combined with double chromosomal deletions of ku70 and ku80. This method resulted in a 13.4-fold increase in integration efficiency compared with the original method, reaching 63% (10/16). The resulting recombinant Y. lipolytica produced 0.41 mg β-carotene per g dry cell weight, while the wild type did not produce any indicating the functionality of the multifunctional carotene synthase in Y. lipolytica. Expression of GGS1 and a multifunctional carotene synthase from Schizochytrium sp. in Y. lipolytica led to β-carotene production. DNA assembler efficiency was greatly increased by the deletion of ku70 and ku80, which resulted in decreased in vivo nonhomologous end-joining (NHEJ) in Y. lipolytica.

Micropropagation of Ajuga species: a mini review.

Abstract: The genus Ajuga L., belonging to Lamiaceae family, is widespread. The demand for Ajuga species has risen sharply because of their medicinal, ornamental, and pharmacological properties. These wide-ranging plants are being rapidly depleted due to over-collection for ornamental and medicinal purposes, as well as by habitat destruction and deforestation. Ajuga boninsimae, A. bracteosa, A. ciliate, A. genevensis, A. incisa, A. makinoi, A. multiflora, A. pyramidalis, A. shikotanensis, A. reptans, and A. vestita are categorized and protected as endangered plants. In vitro plant culture has therefore emerged for the conservation and mass clonal propagation of rare plants. This mini-review covers the current in vitro scenario in the propagation of Ajuga species. Adventitious or axillary shoots are initiated on the leaf, petiole and internodes, as well as roots, nodes, and shoot tip explants. Shoot induction is predominantly dependent on plant growth regulators added to the culture medium. Full- or half-strength Murashige and Skoog medium with or without auxin is used for in vitro rooting. Rooted shoots need to be acclimatized in the greenhouse with an estimated 82-100% survival rate.

Tumor necrosis factor-α and transforming growth factor-β1 facilitate differentiation and proliferation of tendon-derived stem cells in vitro

Abstract: To investigate the effects of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) on the proliferation and differentiation of tendon-derived stem cells (TDSC). TNF-α inhibits the proliferation and tenogenic/osteogenic differentiation of TDSC but, after simultaneous or sequential treatment with TGF-β1 and TNF-α, the expression of tenogenic/osteogenic-related marker and proliferation of TDSC was significantly increased. During these processes, Smad2/3 and Smad1/5/8 were highly phosphorylated, meaning that the TGF-β and BMP signaling pathways were highly activated. Further study revealed that the expression of Inhibitor-Smad appeared to be negatively correlated to the proliferation and differentiation of TDSC. Combining the use of TNF-α and TGF-β1 could improve the proliferation and differentiation of TDSC in vitro, and the expression of I-Smad is negatively correlated with TDSC proliferation and differentiation.

MicroRNA-15b silencing inhibits IL-1β-induced extracellular matrix degradation by targeting SMAD3 in human nucleus pulposus cells

Abstract: To determine the role of microRNA-15b (miR-15b) in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation in the nucleus pulposus (NP). MiR-15b was up-regulated in degenerative NP tissues and in IL-1β-stimulated NP cells, as compared to the levels in normal controls (normal tissue specimens from patients with idiopathic scoliosis). Bioinformatics and luciferase activity analyses showed that mothers against decapentaplegic homolog 3 (SMAD3), a key mediator of the transforming growth factor-β signaling pathway, was directly targeted by miR-15b. Functional analysis demonstrated that miR-15b overexpression aggravated IL-1β-induced ECM degradation in NP cells, while miR-15b inhibition had the opposite effects. Prevention of IL-1β-induced NP ECM degeneration by the miR-15b inhibitor was attenuated by small-interfering-RNA-mediated knockdown of SMAD3. In addition, activation of MAP kinase and nuclear factor-κB up-regulated miR-15b expression and down-regulated SMAD3 expression in IL-1β-stimulated NP cells. MiR-15b contributes to ECM degradation in intervertebral disc degeneration (IDD) via targeting of SMAD3, thus providing a novel therapeutic target for IDD treatment.

Improved campesterol production in engineered Yarrowia lipolytica strains

Abstract: To engineer Yarrowia lipolytica for improving the heterologous production of campesterol (a key precursor to manufacture pharmaceutical steroids). By screening 7-dehydrocholesterol reductase (DHCR7) from diverse species, DHCR7 from Danio rerio was the best candidate for campesterol synthesis. Overexpression of ACL (ATP: citrate lyase) or POX2 (peroxisome acyl-CoA oxidase 2) were key to improving campesterol production. The highest yield of campesterol was 942 mg/l was with the strain overexpressing POX2 in a 5 l bioreactor via high cell density fermentation process with a restricted supply of carbon sourc, sunflower seed oil. A promising platform to synthesize downstream steroid drugs was established. Efficient approaches were provided to improve the production of desired molecules in Y. lipolytica with high oil utilization efficiency.

Identification of strong promoters based on the transcriptome of Bacillus licheniformis.

Abstract: To expand the repertoire of strong promoters for high level expression of proteins based on the transcriptome of Bacillus licheniformis. The transcriptome of B. licheniformis ATCC14580 grown to the early stationary phase was analyzed and the top 10 highly expressed genes/operons out of the 3959 genes and 1249 operons identified were chosen for study promoter activity. Using beta-galactosidase gene as a reporter, the candidate promoter pBL9 exhibited the strongest activity which was comparable to that of the widely used strong promoter p43. Furthermore, the pro-transglutaminase from Streptomyces mobaraensis (pro-MTG) was expressed under the control of promoter pBL9 and the activity of pro-MTG reached 82 U/ml after 36 h, which is 23% higher than that of promoter p43 (66.8 U/ml). In our analyses of the transcriptome of B. licheniformis, we have identified a strong promoter pBL9, which could be adapted for high level expression of proteins in the host Bacillus subtilis.

Combinatorial analysis of enzymatic bottlenecks of L-tyrosine pathway by p-coumaric acid production in Saccharomyces cerevisiae.

Abstract: To identify new enzymatic bottlenecks of l-tyrosine pathway for further improving the production of l-tyrosine and its derivatives. When ARO4 and ARO7 were deregulated by their feedback resistant derivatives in the host strains, the ARO2 and TYR1 genes, coding for chorismate synthase and prephenate dehydrogenase were further identified as new important rate-limiting steps. The yield of p-coumaric acid in the feedback-resistant strain overexpressing ARO2 or TYR1, was significantly increased from 6.4 to 16.2 and 15.3 mg l−1, respectively. Subsequently, we improved the strain by combinatorial engineering of pathway genes increasing the yield of p-coumaric acid by 12.5-fold (from 1.7 to 21.3 mg l−1) compared with the wild-type strain. Batch cultivations revealed that p-coumaric acid production was correlated with cell growth, and the formation of by-product acetate of the best producer NK-M6 increased to 31.1 mM whereas only 19.1 mM acetate was accumulated by the wild-type strain. Combinatorial metabolic engineering provides a new strategy for further improvement of l-tyrosine or other metabolic biosynthesis pathways in S. cerevisiae.

Maximizing power generation from dark fermentation effluents in microbial fuel cell by selective enrichment of exoelectrogens and optimization of anodic operational parameters.

Abstract: To selectively enrich an electrogenic mixed consortium capable of utilizing dark fermentative effluents as substrates in microbial fuel cells and to further enhance the power outputs by optimization of influential anodic operational parameters. A maximum power density of 1.4 W/m3 was obtained by an enriched mixed electrogenic consortium in microbial fuel cells using acetate as substrate. This was further increased to 5.43 W/m3 by optimization of influential anodic parameters. By utilizing dark fermentative effluents as substrates, the maximum power densities ranged from 5.2 to 6.2 W/m3 with an average COD removal efficiency of 75% and a columbic efficiency of 10.6%. A simple strategy is provided for selective enrichment of electrogenic bacteria that can be used in microbial fuel cells for generating power from various dark fermentative effluents.

MAPK/ERK signalling is required for zebrafish cardiac regeneration

Abstract: To better understand the molecular mechanisms of regeneration and explore the potential signalling pathways as therapeutic targets for heart attacks. After treatment with the MEK inhibitor AZD6244 upon cardiac injury, the core members in MAPK/ERK signalling—mek and erk—demonstrate elevated expression, and these proteins are deposited at the injury site in zebrafish. pERK is also induced in non-cardiomyocytes near the injury site. Furthermore, the induced expression of a dominant-negative form of MEK1 inhibits zebrafish cardiac regeneration, characterized by increased cardiac fibrosis (a hallmark of regenerative failure), reduced or delayed production of regenerative myocardium, and migration of FLI1+ endothelial cells, without direct inhibition of cardiomyocyte proliferation. Appropriate activation of MAPK/ERK signalling is essential for zebrafish cardiac regeneration.