Controllable Star Cationic Poly(Disulfide)s Achieve Genetically Cascade Catalytic Therapy by Delivering Bifunctional Fusion Plasmids

The absence of effective delivery vectors and suitable multifunctional plasmids limits cancer gene therapy development. The star cationic poly(disulfide)s with β-cyclodextrin cores (termed β-CD-g-PSSn ) for caveolae-mediated endocytosis are designed and prepared via mild and controllable disulfide exchange polymerization for high-efficacy cancer therapy. Then, β-CD-g-PSSn /pDNA complexes are transported to the Golgi apparatus and endoplasmic reticulum. Disulfides in β-CD-g-PSSn vectors are degraded by glutathione in tumor cells, which not only promotes intracellular pDNA release but also reduces in vitro and in vivo toxicity. One bifunctional fusion plasmid pCATKR, which expresses catalase (CAT) fused to KillerRed (KR) (CATKR) in the same target cell, is also proposed for genetically cascade catalytic therapy. When compared with pCAT-KR (plasmid expressing CAT and KR separately in the same cell), delivered pCATKR decomposes hydrogen peroxide, alleviates tumor hypoxia more effectively, generates stronger reactive oxygen species (ROS) capabilities under moderate irradiation, and leads to robust antitumor cascade photodynamic effects. These impressive results are attributed to fusion protein design, which shortens the distance between CAT and KR catalytic centers and leads to improved ROS production efficiency. This work provides a promising strategy by delivering a catalytic cascade functional plasmid via a high-performance vector with biodegradable and caveolae-mediated endocytosis characteristics.

Aspergillus niger fermentation residues application to produce biochar for the anode of lithium-ion batteries

Aspergillus niger is widely applied in the fermentation industry, but produce abundant mycelium residues every year. As a kind of solid waste, mycelium residues seriously affect the environment. How to manage and utilize this solid waste is a problem for the fermentation industry. It was reported that many kinds of biomass could be utilized to produce carbon materials, which would be further used to produce lithium-ion rechargeable batteries (LIBs). Here, porous biochar was prepared from A. niger mycelial residues and further used as an anode for LIBs. Since the A. niger mycelium contains abundant nitrogen (5.29%) from its chitosan-dominated cell wall, and silicon (9.63%) from perlite filter aid, respectively, the biochar presented an excellent cycle stability and rate performance when applied as the anode of LIBs. The conclusion of this research shows the wide application prospect of fungal fermentation residues as carbon precursors in energy storage devices. Meanwhile, this investigation provides an alternative management method for A. niger mycelium residues, with which the mycelium residues could be effectively recycled to avoid resource waste and environmental pollution.

MIW1 participates in ABA signaling through the regulation of MYB30 in Arabidopsis

Seed germination and seedling establishment are critical biological processes, and their underlying molecular mechanisms have practical implications. The ABA signaling during seed germination and early seedling development is negatively regulated by transcription factor MYB30, but its interaction partners and downstream targets are not fully understood. In this study, we identified MIW1 (MYB30-interacting WD40 protein 1), a WD40 protein that could interact with MYB30 and promote its degradation. In the miw1 mutant, the MYB30 protein became more stable. MIW1 enhanced the ABA-mediated inhibition of postgerminative development. The miw1 mutants became hyposensitive to exogenous ABA, and this effect was suppressed by mutations in MYB30. Furthermore, we found that MYB30 negatively regulated the expression of the ABA receptor genes PYR1/PYL/RCARs. The changes in PYLs expression during early seedling development or under ABA treatment became more pronounced in the myb30 mutant. ChIP-qPCR analyses showed MYB30 could directly bind to the promoters of PYL11 and PYL12. Our study reveals that the WD40 protein MIW1 promotes the expression of PYLs by destabilizing MYB30, thus positively regulating the ABA signaling during postgermination in Arabidopsis.

Excessive consumption of mucin by over-colonized Akkermansia muciniphila promotes intestinal barrier damage during malignant intestinal environment

Gut microbiota disorders damage the intestinal barrier, which causes intestinal disease. Thus, we screened the microbiota with significant changes using an in situ malignant colorectal cancer (CRC) model. Among the colonies with increased abundance, Akkermansia muciniphila (A. muciniphila) is known for its characteristic of breaking down mucin, which is an essential component of the intestinal barrier. The role of A. muciniphila remains controversial. To investigate the effect of excess A. muciniphila on the intestinal barrier, we established an over-colonized A. muciniphila mouse model by administering a live bacterial suspension after disrupting the original gut microbiome with antibiotics. The results showed that over-colonization of A. muciniphila decreased intestinal mucin content. The mRNA and protein expression levels of tight junction proteins also decreased significantly in the over-colonized A. muciniphila mouse model. Our findings reveal that excess colonization by A. muciniphila breaks the dynamic balance between mucin secretion and degradation, reduces the thickness of the intestinal mucus layer, and damages the intestinal barrier, which would eventually aggravate the development of colitis and CRC. These results will raise awareness about the safety of A. muciniphila serving as a probiotic.

[Soft tissue reconstruction strategy for sacral tumor resection]

Objective: To investigate the clinical strategy and effect of soft tissue reconstruction after sacral tumor resection in different planes. Methods: The data of 27 consecutive patients who underwent primary or secondary sacral tumor resection and soft tissue reconstruction from June 2012 to June 2021 at Dongnan Hospital of Xiamen University (the 909th Hospital) were retrospectively analyzed. There were 11 males and 16 females, aged (M(IQR)) (46.2±23.6) years (range: 16 to 72 years). Sacrospinous muscle, gluteus maximus and vertical rectus abdominis muscle flap were selected for soft tissue reconstruction according to the tumor site and the size of tissue defect. the postoperative follow-up was performed. The operative methods, intraoperative conditions, complications and disease outcomes were summarized. Results: Among the 27 patients with sacral tumor, the tumor plane was located in S₁ in 8 cases, S₂ in 5 cases and S₃ or below in 14 cases. There were 12 patients with tumor volume≤400 cm³ and 15 patients with tumor volume>400 cm³. Operation time was 100(90) minutes (range: 70 to 610 minutes), intraoperative blood loss was 800(1 600) ml (range: 400 to 6 500 ml). Soft tissue reconstruction was performed by transabdominal rectus abdominis transfer repair in 2 cases, extraperitoneal rectus abdominis transfer repair in 1 case, gluteus maximus transfer repair in 5 cases, gluteus maximus advancement repair in 13 cases, and sacrospinous muscle transfer repair in 6 cases. Postoperative complications occurred in 6 cases, including 1 case of incision infection, 4 cases of skin border necrosis, and 1 case of delayed infection due to fracture of internal fixator 3 years after operation, all of them were cured. The follow-up time was (35±21) months. Among the patients, 6 patients had recurrence, 2 patients with Ewing sarcoma died of lung metastasis 1 year after operation, 4 patients with metastatic cancer died of primary disease, and the remaining patients survived without disease. Conclusion: Choosing different soft tissue reconstruction strategies according to sacral tumor location and tissue defect size can effectively fill the dead space after sacral tumor resection, reduce postoperative complications and improve the prognosis of patients.

Lycium barbarum Glycopeptide prevents the development and progression of acute colitis by regulating the composition and diversity of the gut microbiota in mice

In most cases, recurrent chronic colitis is caused by the recurrence of acute colitis after incomplete recovery and re-exposure to irritating factors, and the gut microbiome, which is the largest micro-ecosystem in the human body, plays a crucial role in the development of colitis. Plant polysaccharides have always been reported to have the ability for anti-inflammation, and they are closely related to the gut microbiome. Lycium barbarum Glycopeptide (LbGP), the most potent component obtained by further isolation and purification from Lycium barbarum fruit, has been shown to inhibit inflammation in animal models. However, its therapeutic efficacy in colitis and its mechanism in gut microbiota regulation have not been fully studied. In our study, the dextran sulfate sodium (DSS)-induced mouse model was used to dynamically evaluate the effect of LbGP in the treatment of acute colitis and the mechanism from the perspective of the gut microbiome through the 16S rDNA sequence. The results showed that LbGP treatment significantly alleviated acute colitis and improved the gut microbiome compared with that in the model group. Harmful bacteria, such as Lachnoclostridium spp. and Parabacteroides_distasonis, were inhibited and probiotics, such as Bacteroides_acidifaciens, Lactobacillus spp., Turicibacter spp., and Alistipes spp., were increased by LbGP treatment. Further, a Random Forest analysis with 10-fold cross-validation identified a family named Muribaculaceae representing colitis development and recovery upon LbGP treatment. In conclusion, our study demonstrated the capability of LbGP to prevent the development of acute colitis by regulating the composition and diversity of the gut microbiota and highlighted the dynamic process of gut microbiota with the colitis progression. Further, it provides evidence to develop LbGP as a functional food supplement and future drug acting on intestinal disease.

Feasible Cluster Model Method for Simulating the Redox Potentials of Laccase CueO and Its Variant

Laccases are regarded as versatile green biocatalysts, and recent scientific research has focused on improving their redox potential for broader industrial and environmental applications. The density functional theory (DFT) quantum mechanics approach, sufficiently rigorous and efficient for the calculation of electronic structures, is conducted to better comprehend the connection between the redox potential and the atomic structural feature of laccases. According to the crystal structure of wild type laccase CueO and its variant, a truncated miniature cluster model method was established in this research. On the basic of thermodynamic cycle, the overall Gibbs free energy variations before and after the one-electron reduction were calculated. It turned out that the trends of redox potentials to increase after variant predicted by the theoretical calculations correlated well with those obtained by experiments, thereby validating the feasibility of this cluster model method for simulating the redox potentials of laccases.

The Arabidopsis Mitochondrial Pseudouridine Synthase Homolog FCS1 Plays Critical Roles in Plant Development

As the most abundant RNA modification, pseudouridylation has been shown to play critical roles in Escherichia coli, yeast and humans. However, its function in plants is still unclear. Here, we characterized leaf curly and small 1 (FCS1), which encodes a pseudouridine synthase in Arabidopsis. fcs1 mutants exhibited severe defects in plant growth, such as delayed development and reduced fertility, and were significantly smaller than the wild type at different developmental stages. FCS1 protein is localized in the mitochondrion. The absence of FCS1 significantly reduces pseudouridylation of mitochondrial 26S ribosomal RNA (rRNA) at the U1692 site, which sits in the peptidyl transferase center. This affection of mitochondrial 26S rRNA may lead to the disruption of mitochondrial translation in the fcs1-1 mutant, causing high accumulation of transcripts but low production of proteins. Dysfunctional mitochondria with abnormal structures were also observed in the fcs1-1 mutant. Overall, our results suggest that FCS1-mediated pseudouridylation of mitochondrial 26S rRNA is required for mitochondrial translation, which is critical for maintaining mitochondrial function and plant development.

The MIEL1-ABI5/MYB30 regulatory module fine tunes abscisic acid signaling during seed germination

The transcription factor ABSCISIC ACID INSENSITIVE5 (ABI5) plays a crucial role in abscisic acid (ABA) signaling during seed germination. However, how ABI5 is regulated during this process is poorly understood. Here, we report that the ubiquitin E3 ligase MIEL1 and its target transcription factor MYB30 modulate ABA responses in Arabidopsis thaliana during seed germination and seedling establishment via the precise regulation of ABI5. MIEL1 interacts with and ubiquitinates ABI5 to facilitate its degradation during germination. The transcription factor MYB30, whose turnover is mediated by MIEL1 during seed germination, also interacts with ABI5 to interfere with its transcriptional activity. MYB30 functions downstream of MIEL1 in the ABA response, and both are epistatic to ABI5 in ABA-mediated inhibition of seed germination and postgerminative growth. ABA treatment induces the degradation of MIEL1 and represses the interaction between MIEL1 and ABI5/MYB30, thus releasing both ABI5 and MYB30. Our results demonstrate that MIEL1 directly mediates the proteasomal degradation of ABI5 and inhibits its activity via the release of its target protein MYB30, thus ensuring precise ABA signaling during seed germination and seedling establishment.

Construction of fatty acid derivatives from rubber seed oil as α-glucosidase inhibitors based on rubber seed oil

Natural free fatty acids show inhibitory effects on α-glucosidase and can hence have potential applications in diabetes treatment. This study indicated that the inhibitory effect of fatty acids showed a significant negative correlation with affinity energy (- 0.87) and melting point (- 0.88). Guided by this relationship, two promotion strategies of hydration and esterification were put forward to increase the inhibitory effect of fatty acids on α-glucosidase. The hydration can import an extra hydroxy group into the C=C bond of fatty acids, that will enhance the interaction with α-glucosidase, while the esterification will lower the melting point of fatty acids, and promote the inhibitory effect. Hydroxy fatty acids and fatty acid isopropyl esters possessed higher inhibitory effects than the natural fatty acids. Then, rubber seed oil was modified into novel fatty acid derivatives with higher inhibitory effect on α-glucosidase. The inhibitory IC50 of hydroxy products and isopropanol esters was 0.42 ± 0.01 μM and 0.57 ± 0.01 μM, respectively. The result reveals a feasible route to construct fatty acid derivatives from natural oil with α-glucosidase inhibitory effect.

Recent Advances in the Surface Functionalization of Nanomaterials for Antimicrobial Applications

Innovations in nanotechnology have had an immense impact on medicine, such as in drug delivery, tissue engineering, and medical devices that combat different pathogens. The pathogens that may cause biofilm-associated nosocomial diseases are multidrug-resistant (MDR) bacteria, such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), including both Gram-positive and Gram-negative bacterial species. About 65-80% of infections are caused by biofilm-associated pathogens creating a move in the international community toward developing antimicrobial therapies to eliminate such pathogenic infections. Several nanomaterials (NMs) have been discovered and significantly employed in various antipathogenic therapies. These NMs have unique properties of singlet oxygen production, high absorption of near-infrared irradiation, and reasonable conversion of light to heat. In this review, functionalized NPs that combat different pathogenic infections are introduced. This review highlights NMs that combat infections caused by multidrug-resistant (MDR) and other pathogenic microorganisms. It also highlights the biomedical application of NPs with regard to antipathogenic activities.

Enhanced Bioavailability of Dihydrotanshinone I-Bovine Serum Albumin Nanoparticles for Stroke Therapy

Dihydrotanshinone I (DHT) is a natural component in Salvia miltiorrhiza and has been widely researched for its multiple bioactivities. However, poor solubility and biocompatibility of DHT limit its desirable application for clinical purposes. Herein, DHT was encapsulated with bovine serum albumin (BSA) to enhance bioavailability. Compared to free DHT, DHT-BSA NPs (nanoparticles) showed an improved solubility in normal saline and increased protection against hydrogen peroxide-induced oxidative damage in PC12 cells. In addition, DHT-BSA NPs administered by intravenous injection displayed a significant efficacy in the middle cerebral artery occlusion/reperfusion models, without any impact on the cerebral blood flow. In summary, DHT-BSA NPs show an enhanced bioavailability compared with free DHT and a successful penetration into the central nervous system for stroke therapy, demonstrating their application potential in cardio-cerebrovascular diseases.

The conversion of linoleic acid into hydroxytetrahydrofuran-structured bio-lubricant

In this work, a new structured linoleic-based hydroxytetrahydrofuran (HTHF) ester lubricant with excellent properties was developed. A synthesis route through regioselective enzymatic hydration was established, combining highly selective epoxidation with an intramolecular epoxide ring-opening reaction. The results proved that the enzymatic-chemical method is an alternative strategy for the conversion of linoleic acid into bio-lubricants. LiBr was revealed as an efficient catalyst (yields of 95.8%, and selectivity of 98.5%, respectively) for the intramolecular epoxide ring-opening reaction. The tribological properties test indicated that the HTHF bio-lubricants exhibited better performance than the commercial mineral oils. Physicochemical investigation further indicated that the product has a good thermal stability, with the T_onset around 300 °C. The kinematic viscosity and viscosity index indicated that the product is suitable to be applied for lubrication. In contrast with previous findings, this HTHF-structured bio-lubricant oil exhibited a superior low pour point (-64 °C) and provided great potential to be utilized in extreme cold working environments.

[Macrophage migration inhibitory factor meditates MPP+/MPTP-induced NLRP3 inflammasome activation in microglia cells]

OBJECTIVE

To explore the mechanisms of macrophage migration inhibitory factor (MIF)/nucleus factor-κB (NF-κB) in mediating 1-methyl-4-phenylpyridinium iodide (MPP +)/1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced activation of Nod-like receptor protein 3 (NLRP3) inflammasome in microglials and the its effects on neurons.

METHODS

Murine microglial cell line Bv-2 was infected with a lentivirus carrying MIF shRNA for MIF knockdown and then treated with MPP+. The total protein levels of NLRP3, caspase-1, p65 and p65 in the cell nuclei and cytoplasm were detected. ELISA was used to detect the levels of IL-1β and IL-18 in the culture supernatant, which served as the conditioned culture medium for MN9D cells, whose TH expression level was detected using Western blotting. The effect of stereotactic injection of an adeno-associated virus (AAV) carrying MIF shRNA on behaviors was assessed in a C57BL/6 mouse model of Parkinson disease (PD) induced by intraperitoneal MPTP injection. TH and Iba-1 immunohistochemistry was used to evaluate the number of substantia nigra neurons and the activation of microglia cells, and the protein expressions of MIF, NLRP3 and TH in the substantia nigra were detected with Western blotting.

RESULTS

MPP+ significantly increased NLRP3 and MIF expressions in Bv-2 cells (P < 0.05). MIF knockdown in Bv-2 cells significantly lowered NLRP3 and caspase-1 protein expressions and IL-1β and IL-18 levels in the culture supernatant (P < 0.05) without affecting total protein level of p65. Bv-2 cells with MIF knockdown showed significantly lowered p65 protein expression in the nuclei but increased p65 expression in the cytoplasm (P < 0.05). The conditioned medium derived from Bv-2 cells with MIF knockdown, as compared with that from than MPP +-treated Bv-2 cells, significantly increased TH expression in MN9D cells (P=0.01). Compared with those in MPTP group, the mice receiving injections of AAV-MIF-shRNA had higher scores in pole test and open field test with lower scores in traction test, and showed increased TH-positive neurons, decreased Iba-1 microglia cell activation, reduced expressions of MIF and NLRP3, and increased expression of TH in he substantia nigra (all P < 0.05).

CONCLUSION

Inhibition of MIF can reduce the expression of NLRP3 inflammasomes and inflammatory factor caused by MPP+ in microglia cells to relieve the damage of dopaminergic neurons and alleviate microglia cell activation, thus offering protection against neuroinflammation in Parkinson's disease.

One-Step Synthesis of 4-Octyl Itaconate through the Structure Control of Lipase

4-Octyl itaconate is a novel antiviral and immunoregulatory small molecule showing great potential in the treatment of various autoimmune diseases and viral infections. It is difficult to selectively esterify the C4 carboxyl group of itaconate acid via one-step direct esterification using chemical catalysts, while the two-step route with itaconic anhydride as an intermediate is environmentally unfriendly and costly. This research investigated the one-step and green synthesis of 4-octyl itaconate through the structure control of lipase, obtaining 4-octyl itaconate with over 98% yield and over 99% selectivity. Multiscale molecular dynamics simulations were applied to investigate the reaction mechanism. The cavity pocket of lipases resulted in a 4-octyl itaconate selectivity by affecting distribution of substrates toward the catalytic site. Toluene could enhance monoesterification in the C4 carboxyl group and contribute to a nearly 100% conversion from itaconate acid into 4-octyl itaconate by adjusting the catalytic microenvironment around the lipase, producing a shrinkage effect on the channel.

Synthesis of middle-long-middle structured intralipids by biological catalysis and the evaluation of intralipids' protective effect on liver injury rats

Intralipids are widely used to provide energy and necessary fatty acids for the patients. The structure of lipids may affect their function. We developed a bio-catalyzed route to prepare various intralipids and investigated the protective effect of intralipids against α-naphthylisothiocyanate (ANIT) induced liver injury rats, further discussing the structure-function relationship. The middle-long-middle (MLM) structural intralipid was synthesized through alcoholysis-esterification, and the influence factors were investigated. ANIT treatment caused liver injury, further making hepatocyte damage, and increasing related biochemical indexes, like aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and total bilirubin (TBIL). Especially, MLM-based and structoglyceride (STG) intralipids worked better in the early stage, to reduce the AST, ALT, and TBIL (p < .05). MLM showed a comparative advantage over other intralipids to accelerate the reduction of ALT (1st day) and AST (3rd day). MLM intralipid might be a promising next-generation intralipid than the current STG intralipid liver-injury patients. The biological catalysis MLM-based intralipids can make the maximum utilization of fatty acids for the liver regeneration, where middle-chain fatty acid (MCFA) in sn-1,3 position can be metabolized directly to provide energy and long-chain fatty acid (LCFA) in sn-2 position can be delivered effectively for cell membrane repairing.

Tunnel engineering for modulating the substrate preference in cytochrome P450BsβHI

An active site is normally located inside enzymes, hence substrates should go through a tunnel to access the active site. Tunnel engineering is a powerful strategy for refining the catalytic properties of enzymes. Here, P450BsβHI (Q85H/V170I) derived from hydroxylase P450Bsβ from Bacillus subtilis was chosen as the study model, which is reported as a potential decarboxylase. However, this enzyme showed low decarboxylase activity towards long-chain fatty acids. Here, a tunnel engineering campaign was performed for modulating the substrate preference and improving the decarboxylation activity of P450BsβHI. The finally obtained BsβHI-F79A variant had a 15.2-fold improved conversion for palmitic acid; BsβHI-F173V variant had a 3.9-fold improved conversion for pentadecanoic acid. The study demonstrates how the substrate preference can be modulated by tunnel engineering strategy.

The highly-stable immobilization of enzymes on a waste mycelium carrier

Mycelium is an abundant waste from the fermentation industry, and the environmental problems associated with its required disposal seriously limited the development of fermentation industry. In China, millions of tons of various kinds of mycelium residues were produced each year. Research into providing added-value to mycelium, while avoiding its disposal, is hence of paramount importance. Mycelium can be used as carrier for enzymes, while the enzyme immobilization moreover improves their stability and lifetime performance. Carrier recycling, the natural degradation and disposal of artificial polymer carriers are critical issues in immobilization. This research investigated its use to manufacture a highly-stable immobilized enzyme. An acid pretreatment was employed to enhance the adsorption ability of mycelium, and its adsorption ability was compared with other carriers. Under the optimal conditions, a core-shell immobilized enzyme with porous structure was obtained. The stability and the recycle results of the evaluation indicated the excellent performance of the immobilized enzyme. The mycelium recycling was also investigated to verify the practicability. All the results indicated that the use of a mycelium-based carrier was a promising strategy for the reutilization of the fermentation waste, and this technique provides an alternative way to reduce the total amount of the waste mycelium. Meanwhile, the stability and reusability performance of the mycelium-based immobilization could also decrease the influence of the disposal of the solid waste from denatured enzymes to the environment.

An Antioxidant Enzyme Therapeutic for COVID-19

The COVID-19 pandemic has taken a significant toll on people worldwide, and there are currently no specific antivirus drugs or vaccines. Herein it is a therapeutic based on catalase, an antioxidant enzyme that can effectively breakdown hydrogen peroxide and minimize the downstream reactive oxygen species, which are excessively produced resulting from the infection and inflammatory process, is reported. Catalase assists to regulate production of cytokines, protect oxidative injury, and repress replication of SARS-CoV-2, as demonstrated in human leukocytes and alveolar epithelial cells, and rhesus macaques, without noticeable toxicity. Such a therapeutic can be readily manufactured at low cost as a potential treatment for COVID-19.

ABI5 modulates seed germination via feedback regulation of the expression of the PYR/PYL/RCAR ABA receptor genes

As abscisic acid (ABA) receptors, PYR1/PYL/RCAR (PYLs) play important roles in ABA-mediated seed germination, but the regulation of PYLs in this process, especially at the transcriptional level, remains unclear. In this study, we found that expression of 11 of 14 PYLs changes significantly during seed germination and is affected by exogenous ABA. Two PYLs, PYL11 and PYL12, both of which are expressed specifically in mature seeds, positively modulate ABA-mediated seed germination. However, ABI5 was found to modulate the PYL11- and PYL12-mediated ABA response. In the abi5-7 mutant, ABA hypersensitivity caused by PYL11 and PYL12 overexpression was totally or partially blocked. By contrast, ABI5 regulates the expression of PYL11 and PYL12 by directly binding to their promoters. Moreover, the expression of eight other PYLs is also affected during the germination of abi5 mutants. Promoter analysis revealed that an ABI5-binding region is present next to the TATA box or initiator box. Together, our data demonstrate the role of PYL11 and PYL12 in seed germination. In addition, the identification of PYLs as targets of ABI5 reveals a role of ABI5 in the feedback regulation of ABA-mediated seed germination.

Hydrolysis of food waste by hot water extraction and subsequent Rhizopus fermentation to fumaric acid

Food waste is considered a serious global societal problem. How to degrade of food waste in a green and effective way has been to a hot topic. In this work, a method with hot water extraction pretreatment of food waste was investigated and optimized. Under the optimal conditions, more than half of the solid food waste could be transferred to soluble sugars. Meanwhile, in order to improve the tolerance of Rhizopus arrhizus on the food waste hydrolysate, UV combined with chemical mutagenesis were carried out, and a mutant of Rhizopus RH-7-13-807 was obtained. With the mutant strain, the yield of fumaric acid fermented from food waste increased to 1.8 times compared with the original strain, and 23.94 g/L fumaric acid was obtained from the fermentation. Besides, the COD of food waste was evaluated for the degradation of food waste by the Rhizopus RH-7-13-807. The process would decrease the quantity of food waste to be disposed of, and benefit the environment.

Biodegradation of low-density polyethylene by Microbulbifer hydrolyticus IRE-31

Polyethylene (PE) is one of the most widespread plastic materials. Nevertheless, due to its recalcitrance against biological degradation and the presence of toxic additives, landfilled and carelessly disposed PE products have caused serious pollution in the natural environments. In this work, we aimed to investigate the growth characteristics of Microbulbifer hydrolyticus IRE-31 and its application in the biological degradation of low-density PE. The IRE-31 strain was isolated from marine pulp mill wastes rich in lignin which is a natural complex polymer containing also saturated carbon-carbon bonds like in PE. Following 30 days cultivation of the IRE-31 strain, the biodegradation of linear low-density PE particles was evidenced clearly by morphological changes of the polymer surface monitored by scanning electron microscopy and the formation of additional carbonyl groups in the polymer chains indicated by Fourier transform infrared spectroscopy.

Immobilized bacteria with pH-response hydrogel for self-healing of concrete

Concrete is significant for construction. A problem in application is the appearance of cracks that will damage its strength. An autogenous crack-healing mechanism based on bacteria receives increasing attention in recent years. The bacteria are able to form calcium carbonate (CaCO₃) precipitations in suitable conditions to protect and reinforce the concrete. However, a large number of spores are crushed in aged specimens, resulting in a loss of viability. A new kind of hydrogel crosslinked by alginate, chitosan and calcium ions was introduced in this study. It was observed that the addition of chitosan improved the swelling properties of calcium alginate. Opposite pH response to calcium alginate was observed when the chitosan content in the solution reached 1.0%. With an addition of 1.0% chitosan in hydrogel beads, 10.28% increase of compressive strength and 13.79% increase of flexural strength to the control were observed. The results reveal self-healing properties of concretes. A healing crack of 4 cm length and 1 mm width was observed when using cement PO325, with the addition of bacterial spores (2.54-3.07 × 10⁵/cm³ concrete) encapsulated by hydrogel containing no chitosan.

Performance of bitumen coating sheet using biomass pyrolysis oil

The "green" production of bitumen has raised increasing interest in recent years to reduce the environmental, energy-related and petro-based concerns. Bio-oil, prepared by biomass pyrolysis, can be used as a substitute for petro-based bitumen in bitumen or bitumen-based coatings, for its similar properties of good adhesion and anti-corrosion characteristics as bitumen. Although biomass is a renewable and widespread chemical resource, its high-valued utilization is still difficult. Several studies have qualitatively demonstrated the use of bio-bitumen in practical applications. The present study investigates that adding some bio-oil to traditional bitumen to form a bio-bitumen could help improve the properties of traditional bitumen. Bio-bitumen was prepared from biomass pyrolysis oil and applied to self-adhesive and doped hot-melt sheets. Results of physical properties demonstrate that bio-bitumen is a potential substitute in bitumen coating sheet.Implications: This paper is intended to verify the effect of pyrolyzed bio-oil from wheat straw on the performance of bitumen, as well as the feasibility of application in the coating sheet. Up to now, the research on bio-bitumen is mainly in pavement bitumen. In the present research, bio-bitumen was applied to the coating sheet in different proportions. Interestingly, the prepared coating sheet exhibited higher adhesion. Other performances, such as temperature stability, mechanical strength and temperature flexibility of coating sheet showed improvement in the presence of bio-oil, which indicated the suitability of bio-oil in coating sheet bitumen.

Optimization of the Lipase-Catalyzed Selective Amidation of Phenylglycinol

Ceramides and their analogs have a regulatory effect on inflammatory cytokines expression. It was found that a kind of ceramides analog synthesized from phenylglycinol could inhibit the production of cytokine TNF-α. However, two active hydrogen groups are present in the phenylglycinol molecule. It is difficult to control the process without hydroxyl group protection to dominantly produce amide in the traditional chemical synthesis. A selective catalytic the amidation route of phenylglycinol by lipases was investigated in this research. The results indicated that the commercial immobilized lipase Novozym 435 has the best regio-selectivity on the amide group. Based on the experimental results and in silico simulation, it was found that the mechanism of specific N-acyl selectivity of lipase was not only from intramolecular migration and proton shuttle mechanism, but also from the special structure of active site of enzyme. The optimal reaction yield of aromatic amide compound in a solvent-free system with lipase loading of 15 wt% (to the weight of total substrate) reached 89.41 ± 2.8% with very few of byproducts detected (0.21 ± 0.1% ester and 0.64 ± 0.2% diacetylated compound). Compare to other reported works, this work have the advantages such as low enzyme loading, solvent free, and high N-acylation selectivity. Meanwhile, this Novozym 435 lipase based synthesis method has an excellent regio-selectivity on most kinds of amino alcohol compounds. Compared to the chemical method, the enzymatic synthesis exhibited high regio-selectivity, and conversion rates. The method could be a promising alternative strategy for the synthesis of aromatic alkanolamides.

A Development-Associated Decrease in Osmotic Potential Contributes to Fruit Ripening Initiation in Strawberry (Fragaria ananassa)

Fruit development and ripening are accompanied by a large increase in cellular soluble solid contents, which results in a significant decrease in osmotic potential (DOP). Here, we report that this development-associated DOP contributes to the initiation of ripening in strawberry (Fragaria ananassa Duch., Benihoppe) fruit. We show that fruit water potential significantly decreases at the onset of ripening as a result of the DOP. Further analysis using nuclear magnetic resonance spectroscopy (NMR) indicated that the change in fruit water potential was likely caused by catabolism of large molecules in receptacle cells, and bioinformatic analysis identified a family of osmotin-like proteins (OLP) that have a potential role in osmolyte accommodation. The gene expression of more than half of the OLP members increased substantially at the onset of fruit ripening, and specifically responded to DOP treatment, consistent with a close relationship between DOP and fruit ripening. We report that the DOP induced either by mannitol or water loss, triggered fruit ripening, as indicated by the elevated expression of multiple ripening genes and diverse ripening-associated physiological parameters. Collectively, these results suggest that the DOP contributes to strawberry fruit ripening initiation.

Enzymatic cascade biosynthesis reaction of musky macrolactones from fatty acids

Musky macrolactones are an important group of compounds used in high-valued perfumery. An enzymatic cascade reaction including cytochrome P450 hydroxylase and lipase was explored to biosynthesize musky macrolactones. Firstly, fatty acids were hydroxylated by P450 hydroxylase to produce the corresponding ω-hydroxy fatty acids. Then ω-hydroxy fatty acids were lactonized by lipase. ω-Hydroxy fatty acids can difficultly be synthesized by traditional chemical methods, and the production of these compounds were key constraint factors during the whole reaction. To obtain enough precursors of macrolactones, an efficient production of ω-hydroxy fatty acids was explored. A mutant of P450 BM3 from Bacillus megaterium was used as terminal hydroxylases. To improve the yield of ω-hydroxy fatty acids, the coenzyme regeneration system and auxiliary organic solvent were optimized. The conversion using the P450 BM3 mutant under the biphase system was up to 42% towards ω-hydroxy pentadecanoic acid and 98% towards ω-hydroxy palmitic acid. The results reveal that the musky macrolactones, exaltolide and silvanone supra, could be synthesized in the hydroxylation-lactonization cascade reaction. Finally, 81 mg of exaltolide was obtained from 242 mg pentadecanoic acid, and 199 mg of silvanone supra from 256 mg palmitic acid.

Chemoenzymatic Synthesis of Fragrance Compounds from Stearic Acid

Fatty acids are versatile precursors for fuels, fine chemicals, polymers, perfumes, etc. The properties and applications of fatty acid derivatives depend on chain length and on functional groups and their positions. To tailor fatty acids for desired properties, an engineered P450 monooxygenase has been employed here for enhanced selective hydroxylation of fatty acids. After oxidation of the hydroxy groups to the corresponding ketones, Baeyer-Villiger oxidation could be applied to introduce an oxygen atom into the hydrocarbon chains to form esters, which were finally hydrolyzed to afford either hydroxylated fatty acids or dicarboxylic fatty acids. Using this strategy, we have demonstrated that the high-value-added flavors exaltolide and silvanone supra can be synthesized from stearic acid through a hydroxylation/carbonylation/esterification/hydrolysis/lactonization reaction sequence with isolated yields of about 36 % (for ω-1 hydroxylated stearic acid; 100, 60, 80, 75 % yields for the individual reactions, respectively) or 24 % (for ω-2 hydroxylated stearic acid). Ultimately, we obtained 7.91 mg of exaltolide and 13.71 mg of silvanone supra from 284.48 mg stearic acid.

A Quantum Mechanism Study of the C-C Bond Cleavage to Predict the Bio-Catalytic Polyethylene Degradation

The growing amount of plastic solid waste (PSW) is a global concern. Despite increasing efforts to reduce the residual amounts of PSW to be disposed off through segregated collection and recycling, a considerable amount of PSW is still landfilled and the extent of PSW ocean pollution has become a worldwide issue. Particularly, polyethylene (PE) and polystyrene (PS) are considered as notably recalcitrant to biodegradation due to the carbon-carbon backbone that is highly resistant to enzymatic degradation via oxidative reactions. The present research investigated the catalytic mechanism of P450 monooxygenases by quantum mechanics to determine the bio-catalytic degradation of PE or PS. The findings indicated that the oxygenase-induced free radical transition caused the carbon-carbon backbone cleavage of aliphatic compounds. This work provides a fundamental knowledge of the biodegradation process of PE or PS at the atomic level and facilitates predicting the pathway of plastics’ biodegradation by microbial enzymes.

Effect of Different Carbon Sources on Cellulase Production by Marine Strain Microbulbifer hydrolyticus IRE-31-192

Cellulase is an important enzyme that can be used to breakdown lignocellulose into glucose. Microbulbifer hydrolyticus IRE-31(ATCC 700072) is a kind of marine bacterium, which could grow in high salinity medium and has fast-strong growth ability. In this study, a novel strain was screened from Microbulbifer hydrolyticus IRE-31 through mutations to produce cellulase. The effect of different carbon sources on the growth as well as on the production of cellulase of the new strain was studied. Carboxymethyl-cellulase (CMCase) activity selected to represent cellulase was proven to be effectively promoted while xylose, galactose, and melibiose as well as glucose were used as carbon sources. When xylose and glucose were chosen to be further investigated, 472.57 U/L and 266.01 U/L CMCase activity were obtained from 30 g/L glucose and 10 g/L xylose, respectively. These results clarified the effect of different carbon sources on the production of cellulase, which laid a good foundation for the further research in the production of cellulase by marine bacteria.

Clicky hip alone is not a true risk factor for developmental dysplasia of the hip

AIMS

A clicky hip is a common referral for clinical and sonographic screening for developmental dysplasia of the hip (DDH). There is controversy regarding whether it represents a true risk factor for pathological DDH. Therefore a 20-year prospective, longitudinal, observational study was undertaken to assess the relationship between the presence of a neonatal clicky hip and pathological DDH.

PATIENTS AND METHODS

A total of 362 infants from 1997 to 2016 were referred with clicky hips to our 'one-stop' paediatric hip screening clinic. Hips were assessed clinically for instability and by ultrasound imaging using a simplified Graf/Harcke classification. Dislocated or dislocatable hips were classified as Graf Type IV hips.

RESULTS

The mean age at presentation was 13.8 weeks (12.8 to 14.7). In all 351 out of 362 children (97.0%) had Graf Type I hips (normal) that required no treatment. Nine children (2.5%) had Graf Type II hips but all resolved to Graf Type I hips on follow-up scans. One child (0.3%) had Graf Type III hip dysplasia and one child (0.3%) had an irreducible hip dislocation. The two pathological hips were associated with unilateral limited hip abduction. Mean referrals increased from 12.9 to 23.3 each year (p = 0.002) from the first decade of the study to the second, driven by increasing primary care referrals (5.5 versus 16.7 per year, p < 0.001).

CONCLUSION

Most clicky hips required no treatment other than reassurance to parents. Clicky hips with a normal hip examination should be considered a variant of normal childhood and not a risk factor for DDH. However, an abnormal hip examination including unilateral limited hip abduction should prompt urgent further investigations. Cite this article: Bone Joint J 2017;99-B:1533-6.

Biosynthesis of medium chain length alkanes for bio-aviation fuel by metabolic engineered Escherichia coli

The aim of this work was to study the synthesis of medium-chain length alkanes (MCLA), as bio-aviation product. To control the chain length of alkanes and increase the production of MCLA, Escherichia coli cells were engineered by incorporating (i) a chain length specific thioesterase from Umbellularia californica (UC), (ii) a plant origin acyl carrier protein (ACP) gene and (iii) the whole fatty acid synthesis system (FASs) from Jatropha curcas (JC). The genetic combination was designed to control the product spectrum towards optimum MCLA. Decanoic, lauric and myristic acid were produced at concentrations of 0.011, 0.093 and 1.657mg/g, respectively. The concentration of final products nonane, undecane and tridecane were 0.00062mg/g, 0.0052mg/g, and 0.249mg/g respectively. Thioesterase from UC controlled the fatty acid chain length in a range of 10-14 carbons and the ACP gene with whole FASs from JC significantly increased the production of MCLA.

Rational design of substrate binding pockets in polyphosphate kinase for use in cost-effective ATP-dependent cascade reactions

Adenosine-5'-triphosphate (ATP) is the energy equivalent of the living system. Polyphosphate (polyP) is the ancient energy storage equivalent of organisms. Polyphosphate kinases (PPKs) catalyze the polyP formation or ATP formation, to store energy or to regenerate ATP, respectively. However, most PPKs are active only in the presence of long polyPs, which are more difficult and more expensive to generate than the short polyPs. We investigated the PPK preference towards polyPs by site-directed mutagenesis and computational simulation, to understand the mechanism and further design enzymes for effective ATP regeneration using short polyPs for in vitro cascade reactions, which are highly desired for research and applications. The results suggest that the short polyPs inhibit PPK by blocking the ADP-binding pocket. Structural comparison between PPK (Corynebacterium glutamicum) and PPK (Sinorhizobium meliloti) indicates that three amino acid residues, i.e., lysine, glutamate, and threonine, are involved in the activity towards short polyP by fixing the adenosine group of ADP in between the subunits of the dimer, while the terminal phosphate group of ADP still offers an active site, which presents a binding pocket for ADP. A proposed triple mutant PPK (SMc02148-KET) demonstrates significant activity towards short polyP to form ATP from ADP. The obtained high glutathione titer (38.79 mM) and glucose-6-phosphate titer (87.35 mM) in cascade reactions with ATP regeneration using the triple mutant PPK (SMc02148-KET) reveal that the tailored PPK establishes the effective ATP regeneration system for ATP-dependent reactions.

Rotating packed bed reactor for enzymatic synthesis of biodiesel

The aim of the present work was to study the applicability of rotating packed bed (RPB) for biodiesel through the biocatalytic method. In this research, the RPB facilitated a more homogeneous mixture of substrates due to its higher mass transfer efficiency and better micromixing environment. This was superior to the traditional continuous stirred tank reactor (CSTR) system. Candida sp. 99-125 lipase was used without any organic solvent or additive, and demonstrated a significant catalyst efficiency. The key factors, such as the high gravity factor (β), pattern of the catalyst and methanol-FFA molar ratio etc. were investigated. Under the optimal conditions, the hydrolysis yield of fatty acids was 97.0% after 24h and the esterification yield of biodiesel was 96.0% 6h later. The esterifying yield didn't have an obvious decline in the fifth batch. Consequently, the RPB is an attractive and effective reactor for enzymatic synthesis.