Dynamic network biomarker analysis discovers IbNAC083 in the initiation and regulation of sweet potato root tuberization.

The initiation and development of storage roots (SRs) are intricately regulated by a transcriptional regulatory network. One key challenge is to accurately pinpoint the tipping point during the transition from pre-swelling to SRs and to identify the core regulators governing such a critical transition. To solve this problem, we performed a dynamic network biomarker (DNB) analysis of transcriptomic dynamics during root development in Ipomoea batatas (sweet potato). First, our analysis identified stage-specific expression patterns for a significant proportion (>9%) of the sweet potato genes and unraveled the chronology of events that happen at the early and later stages of root development. Then, the results showed that different root developmental stages can be depicted by co-expressed modules of sweet potato genes. Moreover, we identified the key components and transcriptional regulatory network that determine root development. Furthermore, through DNB analysis an early stage, with a root diameter of 3.5 mm, was identified as the critical period of SR swelling initiation, which is consistent with morphological and metabolic changes. In particular, we identified a NAM/ATAF/CUC (NAC) domain transcription factor, IbNAC083, as a core regulator of this initiation in the DNB-associated network. Further analyses and experiments showed that IbNAC083, along with its associated differentially expressed genes, induced dysfunction of metabolism processes, including the biosynthesis of lignin, flavonol and starch, thus leading to the transition to swelling roots.

Dental Pulp Stem Cell Therapy in Ischemic Stroke: A Meta-Analysis of Preclinical Studies.

OBJECTIVE: More preclinical research evidence has shown that dental pulp stem cells (DPSCs) transplantation is expected to promote the recovery of ischemic stroke (IS), but it still lacks an evidence-based analysis. The purpose of this study was to investigate the effects of DPSCs on neurological function and infarct size in Sprague-Dawley (SD) rats with middle cerebral artery embolization (MCAO). METHODS: According to PRISMA guidelines, the preclinical study of DPSCs in the treatment of IS was screened according to the inclusion and exclusion criteria, and the relevant data and quality were evaluated by two independent researchers; A meta-analysis of histological and behavioral results was performed. RESULTS: Seven studies were finally included, with quality evaluation scores ranging from 8 to 9. Four articles reported modified Neurological Severity Scores (mNSS), three studies reported rotarod test, and six studies reported infarct volume. Meta-analysis showed that the mNSS score decreased by 1.17 times, the rotarod test increased by 1.11 times and the volume of cerebral infarction decreased by 1.91 times in the DPSC group compared with the blank control group. CONCLUSION: Transplantation of DPSCs can significantly improve the neurological function of ischemic stroke and reduce the infarct volume.

The role of JrLACs in the lignification of walnut endocarp.

BACKGROUND: The walnut shell, which is composed of a large number of sclereids originating from the lignified parenchyma of the endocarp, plays an important role in fruit development and during harvesting and storage. The physical and chemical properties of walnut shells are closely related to the lignin content. Laccase is the key enzyme responsible for lignin biosynthesis by the polymerization of monolignols and plays crucial roles in secondary cell wall formation in plants. In this study, we screened and identified laccase family genes from the walnut genome and investigated the expression of laccase during endocarp lignification in walnut. RESULTS: A total of 37 laccase genes were screened from the walnut genome and distributed on nine chromosomes and classified into 6 subfamilies, among which subfamily IV showed distinct expansion. We observed that endocarp lignification started 44 days after flowering (DAF), and at later periods, the lignin content increased rapidly, with growth peaks at 44-50 DAF and 100-115 DAF. The lignification of the endocarp proceeded from the outside to the inside, as demonstrated by section staining in combination with endocarp staining. Furthermore, the changes in the expression of laccase family genes in the endocarp at different developmental stages were studied, and JrLACs showed different expression trends. The expression of nine genes showed significant increase after 44 DAF, and among these, JrLAC12-1, JrLAC12-2 and JrLAC16 showed a significant change in expression at the lignification stage. A study of the expression of JrLACs in different tissues and at various endocarp developmental stages revealed, that most JrLACs were expressed at low levels in mature tissues and at high levels in young tissues, in particular, JrLAC12-1 showed high expression in the young stems. A significant positive correlation was found between the expression of JrLAC12-1 and the variation in the lignin content in the endocarp. CONCLUSION: Laccase genes play an important role in the lignification of the walnut endocarp, and JrLACs play different roles during fruit development. This study shows that JrLAC12-1 may play a key role in the lignification of endocarp.

PEG-PLA nanoparticles facilitate siRNA knockdown in adult zebrafish heart.

The remarkable regenerative capacity of the zebrafish has made it an important model organism for studying heart regeneration. However, current loss-of-function studies are limited by a lack of conditional-knockout and effective gene-knockdown methods for the adult heart. Here, we report a novel siRNA knockdown method facilitated by poly(ethylene glycol)-b-poly(D,L-lactide) (PEG-PLA) nanoparticles. The siRNA-encapsulated nanoparticles successfully entered cells and resulted in remarkable gene-specific knockdown in the adult heart. This effect was demonstrated by down-regulation of the Aldh1a2 and Dusp6 proteins after intrapleural delivery of nanoparticle-encapsulated siRNAs. Furthermore, siRNA-mediated knockdown of Aldh1a2 was sufficient to inhibit myocardial proliferation and decrease the numbers of Gata4-positive cardiomyocytes after ventricular resection. Therefore, the results of this work demonstrate that nanoparticle-facilitated siRNA delivery provides an alternative tool for loss-of-function studies of genes in the adult heart in particular and other organs in general in the adult zebrafish.

The global phosphoproteome of Chlamydomonas reinhardtii reveals complex organellar phosphorylation in the flagella and thylakoid membrane.

Chlamydomonas reinhardtii is the most intensively-studied and well-developed model for investigation of a wide-range of microalgal processes ranging from basic development through understanding triacylglycerol production. Although proteomic technologies permit interrogation of these processes at the protein level and efforts to date indicate phosphorylation-based regulation of proteins in C. reinhardtii is essential for its underlying biology, characterization of the C. reinhardtii phosphoproteome has been limited. Herein, we report the richest exploration of the C. reinhardtii proteome to date. Complementary enrichment strategies were used to detect 4588 phosphoproteins distributed among every cellular component in C. reinhardtii. Additionally, we report 18,160 unique phosphopeptides at <1% false discovery rate, which comprise 15,862 unique phosphosites - 98% of which are novel. Given that an estimated 30% of proteins in a eukaryotic cell are subject to phosphorylation, we report the majority of the phosphoproteome (23%) of C. reinhardtii. Proteins in key biological pathways were phosphorylated, including photosynthesis, pigment production, carbon assimilation, glycolysis, and protein and carbohydrate metabolism, and it is noteworthy that hyperphosphorylation was observed in flagellar proteins. This rich data set is available via ProteomeXchange (ID: PXD000783) and will significantly enhance understanding of a range of regulatory mechanisms controlling a variety of cellular process and will serve as a critical resource for the microalgal community.

Gelatin/polychromatic materials microgels enhanced by carnosic acid inclusions and its application in 2D pattern printing and multi-nozzle food 3D printing.

Natural polychromatic biomaterials (like carminic acid and gardenia yellow) possess coloring merits and functionality, but are instable under light and heat. Self-assembly of gelatin and polychromatic materials could be induced by carnosic acid inclusions, illustrating great potential in food application. Antioxidant properties, pigment retention rates, UV irradiation stability, rheological properties, and physical resistances (oil, ethanol, heat and microwave) of samples were improved by carnosic acid inclusions, owing to the newly formed hydrogen bonding and electrostatic interactions (UV spectrum, particle size, zeta potential, FTIR, XPS and SEM). The improved properties contributed to the 2D printed pattern stability and the applicability for producing specialized products with high printability and fastness. On the basis of Subtractive Color-Mixing Principle, further three-dimensional dyeing microgel systems were built and modulated; it could functionalize bean paste/carboxymethyl-cellulose food systems, maintain the excellent self-supporting ability & mechanical strength, and promote single/dual-nozzle 3D printing application. Therefore, the self-assembled gelatin/polychromatic materials/carnosic acid microgel samples could not only achieve outstanding 2D printed pattern stability, and could be also promisingly applied in single/dual-nozzle 3D printing for modern innovative, creative food fields.

Effect of polyethylene glycol on polysaccharides: From molecular modification, composite matrixes, synergetic properties to embeddable application in food fields.

Polyethylene glycol (PEG) is a flexible, water-soluble, non-immunogenic, as well as biocompatible polymer, and it could synergize with polysaccharides for food applications. The molecular modification strategies, including covalent bond interactions (amino groups, carboxyl groups, aldehyde groups, tosylate groups, etc.), and non-covalent bond interactions (hydrogen bonding, electrostatic interactions, etc.) on PEG molecular chains are discussed. Its versatile structure, group modifiability, and amphiphilic block buildability could improve the functions of polysaccharides (e.g., chitosan, cellulose, starch, alginate, etc.) and adjust the properties of combined PEG/polysaccharides with outstanding chain tunability and matrix processability owing to plasticizing effects, compatibilizing effects, steric stabilizing effects and excluded volume effects by PEG, for achieving the diverse performance targets. The synergetic properties of PEG/polysaccharides with remarkable architecture were summarized, including mechanical properties, antibacterial activity, antioxidant performance, self-healing properties, carrier and delivery characteristics. The PEG/polysaccharides with excellent combined properties and embeddable merits illustrate potential applications including food packaging, food intelligent indication/detection, food 3D printing and nutraceutical food absorption. Additionally, prospects (like food innovation and preferable nutrient utilization) and key challenges (like structure-effectiveness-applicability relationship) for PEG/polysaccharides are proposed and addressed for food fields.

Recent advances of silk fibroin materials: From molecular modification and matrix enhancement to possible encapsulation-related functional food applications.

Silk fibroin materials are emergingly explored for food applications due to their inherent properties including safe oral consumption, biocompatibility, gelatinization, antioxidant performance, and mechanical properties. However, silk fibroin possesses drawbacks like brittleness owing to its inherent specific composition and structure, which limit their applications in this field. This review discusses current progress about molecular modification methods on silk fibroin such as extraction, blending, self-assembly, enzymatic catalysis, etc., to address these limitations and improve their physical/chemical properties. It also summarizes matrix enhancement strategies including freeze drying, spray drying, electrospinning/electrospraying, microfluidic spinning/wheel spinning, desolvation and supercritical fluid, to generate nano-, submicron-, micron-, or bulk-scale materials. It finally highlights the food applications of silk fibroin materials, including nutraceutical improvement, emulsions, enzyme immobilization and 3D/4D printing. This review also provides insights on potential opportunities (like safe modification, toxicity risk evaluation, and digestion conditions) and possibilities (like digital additive manufacturing) in functional food industry.

The prevalence and associated risk factors of sleep disorder-related symptoms in pregnant women in China.

PURPOSE: The sleep disorder in pregnant women remains unfamiliar to perinatal care providers, resulting in lack of appropriate care. This study was designed to investigate the prevalence of sleep disorder-related symptoms in pregnant women and to identify the associated risk factors. METHODS: Married pregnant women were enrolled from their first trimester and followed up until delivery. Nonpregnant married healthy women were selected as controls. A survey questionnaire was administered to each of them. RESULTS: We successfully performed a survey to 1,993 pregnant women and 598 nonpregnant women. The overall prevalence of sleep disorder-related symptoms in pregnant women was significantly higher than the controls (56.1 vs. 29.9 %, P < 0.05). There was higher prevalence of snoring (30.2 %), observed sleep apnea (1.1 %), mouth breathing (23.7 %), nocturnal arousal (46.5 %), insomnia (35.1 %), and daytime sleepiness (52.6 %) in pregnant women. There were no significant differences of the prevalence of bruxism (7.0 vs. 6.7 %), sleep talking (8.1 vs. 7.2 %), and sleep walking (0.4 vs. 0.2 %) between the two groups (P > 0.05). Nocturnal sleep time (8.0 ± 1.3 h) was less in the third trimester compared with the nonpregnant women (8.2 ± 1.1 h) (P < 0.05). Smoking (OR = 3.39), drinking (OR = 2.40), allergic rhinitis/asthma (OR = 1.71), an obvious difference in neck circumference (OR = 1.11), and waistline (OR = 1.07) changes between the first and third trimesters were the risk factors for sleep disorder-related problems. CONCLUSIONS: There is a high prevalence of sleep disorder-related symptoms in pregnant women. Our data may provide a baseline for prevention and treatment of sleep disturbances in pregnant women.

Encapsulation of lutein in gelatin type A/B-chitosan systems via tunable chains and bonds from tweens: Thermal stability, rheologic property and food 2D/3D printability.

Lutein could be stabilized in gelatin type A/B-chitosan systems by different polyoxyethylene sorbitan fatty acid esters (tweens) via tunable chains and bonds, and the homogeneous system held potential in food 2D/3D printing. During encapsulation of lutein in gelatin-chitosan matrix complexes, tween 40, tween 60 and tween 80 assisted in the excellent centrifugation stability, freeze-thaw stability, chemical stability as well as thermal stability. The tweens contained systems also possessed excellent rheological properties, including shearing thinning property, self-supporting characteristics, and favorable thixotropy. Especially, tween 80 performed well in facilitating the stability and rheological properties of systems with uniform micromorphology due to its long alkyl chains and carbon-carbon double bonds (two sp2 hybridized C-atoms) (from FTIR, XRD, SEM, etc.); and gelatin type B illustrated higher protection effects on lutein because of its strong electrostatic interaction with chitosan. The optimal systems could work as edible ink for 2D/3D printing on food with great UV-irradiation stability and high definition. Surimi could be modified by the optimal complex and possessed excellent shear-thinning property, proper yield stress, low dependence on frequency and stable structure, which was successfully applied for innovative 3D printing with sophisticated shapes. The practical food 2D/3D printing (like bread and surimi) demonstrated high potential in food creation and food innovation.

Chitosan particles modulate the properties of cellulose nanocrystals through interparticle interactions: Effect of concentration.

The physical and chemical properties of cellulose nanocrystals (CNC) were regulated by physical crosslinking with chitosan particles (CSp). At a fixed concentration (0.5 wt%) of CNC, varying CSp concentration (0.02-0.5 wt%) influenced the morphologies and chemical properties of the obtained complex particles (CNC-CSp). The results of Fourier transform infrared spectroscopy (FTIR) and zeta potential confirmed the electrostatic and hydrogen bonding interactions between CSp and CNC. At a low CSp concentration (0.02-0.05 wt%), the charge shielding effect induced the formation of particle aggregation networks, thus showing increased viscosity, turbidity and size (153.4-2605.7 nm). At a higher CSp concentration (0.1-0.5 wt%), the hydrogen bonding interaction promoted CSp adsorption onto the surface of CNC, thus facilitating the dispersion of CNC-CSp due to electrostatic repulsion caused by surface-adsorbed CSp. In addition, CSp improved the thermal stability, hydrophobicity (41.87-60.02°) and rheological properties of CNC. Compared with CNC, CNC-CSp displayed a better emulsifying ability and emulsion stability, in which CSp could play a dual role (i.e., charge regulator and stabilizer). This study suggests that introducing CSp can improve the properties and application potentials of CNC as food colloids.

Advances in Rational Protein Engineering toward Functional Architectures and Their Applications in Food Science.

Protein biomolecules including enzymes, cagelike proteins, and specific peptides have been continuously exploited as functional biomaterials applied in catalysis, nutrient delivery, and food preservation in food-related areas. However, natural proteins usually function well in physiological conditions, not industrial conditions, or may possess undesirable physical and chemical properties. Currently, rational protein design as a valuable technology has attracted extensive attention for the rational engineering or fabrication of ideal protein biomaterials with novel properties and functionality. This article starts with the underlying knowledge of protein folding and assembly and is followed by the introduction of the principles and strategies for rational protein design. Basic strategies for rational protein engineering involving experienced protein tailoring, computational prediction, computation redesign, and de novo protein design are summarized. Then, we focus on the recent progress of rational protein engineering or design in the application of food science, and a comprehensive summary ranging from enzyme manufacturing to cagelike protein nanocarriers engineering and antimicrobial peptides preparation is given. Overall, this review highlights the importance of rational protein engineering in food biomaterial preparation which could be beneficial for food science.

Transglutaminase modified type A gelatin gel: The influence of intra-molecular and inter-molecular cross-linking on structure-properties.

In this work, the structure-property differences and mechanisms of gelatin induced by transglutaminase (TGase) covalent cross-linking were investigated. The results showed that higher hardness was obtained with a cross-linking degree of 13.55%, attributing to an active intra-molecular cross-linking and a tight network structure under a certain amount of triple helix-like structure. The inter-molecular cross-linking played a positive role in the transition from random coil to left-handed single helix chains, while triple helix-like structure could not been formed owing to the steric hindrance and hydrogen bond reduction, showing the decrease of hardness and increase of viscosity. Additionally, the ε-(γ-Glu)-Lys isopeptide bond significantly increased the initial degradation temperature. Macromolecular polymers with a cross-linking degree of 37.48% allowed sol state of gelatin gel could be maintained even heating at 100 ℃ for 10 min. This study might provide an innovative reference for the regulation and application of gelatin gel structure-properties.

Biomechanical comparison of vertebral augmentation and cement discoplasty for the treatment of symptomatic Schmorl's node: a finite element analysis.

Percutaneous vertebral augmentation (PVA) and percutaneous cement discoplasty (PCD) are two relatively new minimally invasive surgeries for symptomatic Schmorl's reported in recent decade. However, the clinical evidence for the effectiveness of these two surgeries is insufficient. The purpose of this study was to compare the biomechanical benefits and risks of the two surgeries in order to analyze their biomechanical differences and effectiveness. We reconstructed Five lumbar finite element models via computed tomography data, including control model, PVA-ideal model, PVA-nonideal model, PCD-ideal model, and PCD-nonideal model. The stress and strain of Schmorl's nodes, bone marrow edema zone (BMEZ), affected endplate, and the overall stability of segment were analyzed and compared. The validity of our models was confirmed. As a result, the PVA-ideal model can significantly reduce the stress of Schmorl's node and the strain of BMEZ, while this effect is inappreciable in PVA-nonideal model. The PCD-ideal model significantly reduced the strain of Schmorl's nodes and BMEZ, and significantly improve segmental stability, but also resulted in a significant increase in the stress of Schmorl's nodes, BMEZ and endplates. The PCD-nonideal model not only lacks blocking effect, but also sharply increases the strain of Schmorl's nodes and BMEZ. Thus, We recommend that both PVA and PCD surgeries in ideal distribution facilitated a more stable paranodular biomechanical microenvironment. However, due to the possibility of poor biomechanical outcomes caused by the non-ideal cement distribution, the non-ideal distribution of bone cement needs to be remedied in practice.

Scaffold-mediated non-viral delivery platform for CRISPR/Cas9-based genome editing.

Genome editing, especially via the simple and versatile type II CRISPR/Cas9 system, offers an effective avenue to precisely control cell fate, an important aspect of tissue regeneration. Unfortunately, most CRISPR/Cas9 non-viral delivery strategies only utilise micro-/nano-particle delivery methods. While these approaches provide reasonable genomic editing efficiencies, their systemic delivery may lead to undesirable off-target effects. For in vivo applications, a more localized and sustained delivery approach may be useful, particularly in the context of tissue regeneration. Here, we developed a scaffold that delivers the CRISPR/Cas9 components (i.e. single guide RNA (sgRNA) and Cas9 protein complexes) in a localized and non-viral manner. Specifically, using mussel-inspired bioadhesive coating, polyDOPA-melanin (pDOPA), we adsorbed Cas9:sgRNA lipofectamine complexes onto bio-mimicking fiber scaffolds. To evaluate the genome-editing efficiency of this platform, U2OS.EGFP cells were used as the model cell type. pDOPA coating was essential in allowing Cas9:sgRNA lipofectamine complexes to adhere onto the scaffolds with a higher loading efficiency, while laminin coating was necessary for maintaining cell viability and proliferation on the pDOPA-coated fibers for effective gene editing (21.5% editing efficiency, p < 0.001). Importantly, U2OS.EGFP cells took up Cas9:sgRNA lipofectamine complexes directly from the scaffolds via reverse transfection. Overall, we demonstrate the efficacy of such fiber scaffolds in providing localized, sustained and non-viral delivery of Cas9:sgRNA complexes. Such genome editing scaffolds may find useful applications in tissue regeneration. STATEMENT OF SIGNIFICANCE: Currently, there is a lack of effective non-viral means to deliver CRISPR/Cas9 components for genome editing. Most existing approaches only utilize micro-/nano-particles by injection or systemic delivery, which may lead to undesirable off-target effects. Here, we report a platform that delivers the CRISPR/Cas9 components (i.e. single guide RNA (sgRNA) and Cas9 protein complexes) in a localized and sustained manner. We used mussel-inspired bioadhesive coating to functionalize the bio-mimicking fiber scaffolds with Cas9:sgRNA lipofectamine complexes, to allow effective gene editing for the cells seeded on the scaffolds. Importantly, the cells took up Cas9:sgRNA lipofectamine complexes directly from the scaffolds. Such genome editing scaffolds may find useful applications in tissue regeneration.

Herceptin-conjugated paclitaxel loaded PCL-PEG worm-like nanocrystal micelles for the combinatorial treatment of HER2-positive breast cancer.

We have constructed Herceptin-conjugated, paclitaxel (PTX) loaded, PCL-PEG worm-like nanocrystal micelles (PTX@PCL-PEG-Herceptin) for the combinatorial therapy of HER2-positive breast cancer that exploit the specific targeting of Herceptin to HER2-positive breast cancer cells. Firstly, amphiphilic PCL2000-MPEG2000 and PCL5000-PEG2000-CHO were selected as the optimized matrix to wrap PTX that self-assembled into worm-like micelles with internal nanocrystal structures (PTX@PCL-PEG). Then the aldehydes of PCL5000-PEG2000-CHO exposed on the outside surface of PTX@PCL-PEG were utilized to react with the primary amines of Herceptin and formed stable, carbon-nitrogen single linkers (-C-N-) between the antibodies and nanoparticles. This study shows PTX@PCL-PEG-Herceptin remained relatively stable in the circulation and in the tumor microenvironment, and rapidly targeted and entered into the HER2-overexpressing tumor cells while sparing normal tissues from the toxic effects. PTX@PCL-PEG-Herceptin shrank the tumors and prolonged survival time in a SKBR-3-tumor-xenograft, nude mice model more effectively than TAXOL®, PTX@PCL-PEG, Herceptin+TAXOL® and Herceptin+PTX@PCL-PEG. Mechanistic studies showed that PTX@PCL-PEG-Herceptin entered into the HER2-positive tumor cells through the caveolin-mediated pathway. The conjugated Herceptin greatly enhanced the binding ability of the nanoparticle to the targeted SKBR-3 cells. This novel strategy provides a rational and simple antibody-conjugated-nanoparticle platform for the clinical application of combinatorial anticancer treatment.

Emerging Chitosan-Based Films for Food Packaging Applications.

Recent years have witnessed great developments in biobased polymer packaging films for the serious environmental problems caused by the petroleum-based nonbiodegradable packaging materials. Chitosan is one of the most abundant biopolymers after cellulose. Chitosan-based materials have been widely applied in various fields for their biological and physical properties of biocompatibility, biodegradability, antimicrobial ability, and easy film forming ability. Different chitosan-based films have been fabricated and applied in the field of food packaging. Most of the review papers related to chitosan-based films are focusing on antibacterial food packaging films. Along with the advances in the nanotechnology and polymer science, numerous strategies, for instance direct casting, coating, dipping, layer-by-layer assembly, and extrusion, have been employed to prepare chitosan-based films with multiple functionalities. The emerging food packaging applications of chitosan-based films as antibacterial films, barrier films, and sensing films have achieved great developments. This article comprehensively reviews recent advances in the preparation and application of engineered chitosan-based films in food packaging fields.

Atomic-engineered gold@silvergold alloy nanoflowers for in vivo inhibition of bacteria.

The problems of multidrug-resistant bacteria and environmental pollution associated with the abuse of antibiotics call for effective antibiotic alternatives. Here, gold@silvergold alloy nanoflowers (Au@AgAu ANFs) with distinct atomic structures are first fabricated and then demonstrated for in vivo inhibition of bacteria. The Au@AgAu ANFs display high antibacterial activity against the model Gram-negative bacterium Escherichia coli, with a minimum inhibitory concentration value of 4.8 µg mL-1, which is 3.1 times lower than that of silver nanoparticles. The alloy structure with a rough surface enables Au@AgAu ANFs to firmly adhere to the bacterial surface and damage the cell membrane, resulting in long-term (48 h) and highly stable (30 days) antibacterial activity. Meanwhile, the Au@AgAu ANFs show remarkable biocompatibility with human cells even at a high concentration of 40 µg mL-1. Application of Au@AgAu ANFs in the treatment of bacterial infections in the mouse intestine significantly reduces the reproduction of bacteria compared to an untreated mouse, giving results similar to those of the current antibiotic treatment, with no cytotoxicity. Our study opens up a new avenue for the rational design of safe and highly efficient antibacterial materials.

Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development.

There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the ß-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis.

Overcoming tumor resistance to cisplatin by cationic lipid-assisted prodrug nanoparticles.

Chemotherapy resistance has become a major challenge in the clinical treatment of lung cancer which is the leading cancer type for the estimated deaths. Recent studies have shown that nanoparticles as drug carriers can raise intracellular drug concentration by achieving effectively cellular uptake and rapid drug release, and therefore reverse the acquired chemoresistance of tumors. In this context, nanoparticles-based chemotherapy represents a promising strategy for treating malignancies with chemoresistance. In the present study, we developed cationic lipid assisted nanoparticles (CLAN) to deliver polylactide-cisplatin prodrugs to drug resistant lung cancer cells. The nanoparticles were formulated through self-assembly of a biodegradable poly(ethylene glycol)-block-poly(lactide) (PEG-PLA), a hydrophobic polylactide-cisplatin prodrug, and a cationic lipid. The cationic nanoparticles were proven to significantly improve cell uptake of cisplatin, leading to an increased DNA-Pt adduct and significantly promoted DNA damage in vitro. Moreover, our study reveals that cationic nanoparticles, although are slightly inferior in blood circulation and tumor accumulation, are more effective in blood vessel extravasation. The CLANs ultimately enhances the cellular drug availability and leads to the reversal of cisplatin resistance.