Biosorption and bioreduction of aqueous chromium (VI) by different Spirulina strains.

Spirulina has emerged as a promising microorganism for the treatment of industrial heavy metal ions in wastewater due to their simplicity of cultivation and harvesting, rich functional binding groups, and high bioreductive activity during the uptake process. While the capacities of biosorption and bioreduction for heavy metal ions differ significantly among various algal strains. Therefore, the physiological characteristics were investigated to identify the different Spirulina strains, and the chromium (VI) adsorption capacities of the algal strains were also evaluated. In this study, it was found that algal strains YCX2643 and CLQ1848 performed higher removal efficiency (86.5% and 83.7%) than the other four Spirulina strains (59.4%, 56.3%, 65.6%, and 66.5%, respectively). Moreover, the mechanisms of chromium (VI) ions binding and biotransformation in the Spirulina cell were scrutinized by FTIR (Fourier transform infrared) spectroscopy and scanning electron microscopy (SEM), and it indicated that the varieties of cellular components involved in high binding affinity may cause the higher biosorption and bioreduction of aqueous chromium (VI) in algal strains YCX2643 and CLQ1848, which could be used as promising biosorbents in the removing heavy metal pollutants from wastewaters.

Biotransformation of gallate esters by a pH-stable tannase of mangrove-derived yeast Debaryomyces hansenii.

Introduction: Tannase is a crucial enzyme that finds wide applications in the pharmaceutical industry, feed processing, and beverage manufacturing. Although extensive studies have been conducted on tannases from fungi and bacteria, reports on tannases exhibiting favorable pH stability are relatively limited. Methods: In this study, a tannin-degrading strain Debaryomyces hansenii was screened to induce tannase production, and the corresponding tannase coding gene TANF was successfully cloned and expressed in Yarrowia lipolytica. SDS-PAGE analysis revealed that the purified TanF tannase had a molecular weight of approximately 70 kDa. Results and Discussion: The enzyme demonstrated optimal activity at 40°C and retained over 80% of its activity in the range of 35°C-60°C. Of particular interest, TanF exhibited remarkable enzyme activity at pH 5.0 and retained more than 70% of its relative activity across a wide pH range of 3.0-8.0. Furthermore, TanF exhibited broad substrate specificity for gallate esters. The final gallic acid production by TanF from tannic acid achieved 18.32 g/L. Therefore, the excellent properties TanF has been demonstrated to be an efficient tool for the preparation of gallic acid.

Bioinspired Conductive Enhanced Polyurethane Ionic Skin as Reliable Multifunctional Sensors.

Ionogels prepared from ionic liquid (IL) have the characteristics of nonevaporation and stable performance relative to traditional hydrogels. However, the conductivities of commonly used ionogels are at very low relative to traditional hydrogels because the large sizes of the cation and anion in an IL impedes ion migration in polymer networks. In this study, ultradurable ionogels with suitable mechanical properties and high conductivities are prepared by impregnating IL into a safe, environmentally friendly water-based polyurethane (WPU) network by mimicking the ion transport channels in the phospholipid bilayer of the cell membrane. The increase in electrical conductivity is attributed to the introduction of carboxylic acid in the hard segment of WPU; this phenomenon regularly arranges hard segment structural domains by hydrogen bonding, forming ionic conduction channels. The conductivities of their ionogels are >28-39 mS cm-1 . These ionogels have adjustable mechanical properties that make the Young's modulus value (0.1-0.6 MPa) similar to that of natural skin. The strain sensor has an ultrahigh sensitivity that ranges from 0.99 to 1.35, with a wide sensing range of 0.1%-200%. The findings are promising for various ionotronics requiring environmental stability and high conductivity characteristics.

Silk fibroin based wearable electrochemical sensors with biomimetic enzyme-like activity constructed for durable and on-site health monitoring.

Flexible biomimetic sensors have encountered a bottleneck of sensitivity and durability, as the sensors must directly work within complex body fluid with ultra-trace biomarkers. In this work, a wearable electrochemical sensor on a modified silk fibroin substrate is developed using gold nanoparticles hosted into N-doped porous carbonizated silk fibroin (AuNPs@CSF) as active materials. Taking advantage of the inherent biocompatibility and flexibility of CSF, and the high stability and enzyme-like catalytic activity of AuNPs, AuNPs@CSF-based sensor exhibits durable stability and superior sensitivity to monitor H2O2 released from cancer cell (4T1) and glucose in sweat. The detection limits for H2O2 and glucose are low to be 1.88 µM and 23 µM respectively, and the sensor can be applied in succession within 30 days at room temperature. Further, physical cross-linking of polyurethane (PU) with SF well matches with the skin tissue mechanically and provides a flexible, robust and stable electrode-tissue interface. AuNPs@CSF is applied successfully for wearable electrochemical monitoring of glucose in human sweat.The present AuNPs@CSF will possess a potential application in clinical diagnosing of H2O2- or glucose-related diseases in future.

2D Co3O4 modified by IrO2 nanozyme for convenient detection of aqueous Fe2+ and intercellular H2O2.

A portable sensor for visual monitoring of Fe2+ and H2O2, two-dimensional Co3O4 modified by nano-IrO2 (IrO2@2D Co3O4) was prepared in this work, for the first time, with the help of microwave radiation at 140 °C, which was further stabilized onto common test strips. The present IrO2@2D Co3O4 possessed superior dual-function enzyme-like activity with low toxicity and excellent biocompatibility. Especially, trace Fe2+ and H2O2 could exclusively alter their enzyme-like catalytic activity with discriminating hyperchromic or hypochromic effect, i.e., from blue to colorless or to dark blue for both IrO2@2D Co3O4 dispersion and its functionalized test strips. The linear regression equations were A652 = 0.5940 - 0.00041 cFe2+ (10-8 M, R2 = 0.9927) for Fe2+ and ∆A652 = 0.0023 cH2O2 + 0.00025 (10-7 M, R2 = 0.9982) for H2O2, respectively. When applied to visual monitoring of aqueous Fe2+ and intercellular H2O2, the recoveries were 101.2 ~ 102.5% and 95.8 ~ 103.7% with detection limits of 1.25 × 10-8 mol/L and 1.02 × 10-7 mol/L, respectively, far below the permitted values in drinking water set by the World Health Organization. The mechanisms for the enhancing enzyme-mimetic activity of IrO2@2D Co3O4 and its selective responses to Fe2+ and H2O2 were investigated in detail.

The discovery of a key prenyltransferase gene assisted by a chromosome-level Epimedium pubescens genome.

Epimedium pubescens is a species of the family Berberidaceae in the basal eudicot lineage, and a main plant source for the traditional Chinese medicine "Herba Epimedii". The current study achieved a chromosome-level genome assembly of E. pubescens with the genome size of 3.34 Gb, and the genome guided discovery of a key prenyltransferase (PT) in E. pubescens. Our comparative genomic analyses confirmed the absence of Whole Genome Triplication (WGT-γ) event shared in core eudicots and further revealed the occurrence of an ancient Whole Genome Duplication (WGD) event approximately between 66 and 81 Million Years Ago (MYA). In addition, whole genome search approach was successfully applied to identify 19 potential flavonoid PT genes and an important flavonoid PT (EpPT8) was proven to be an enzyme for the biosynthesis of medicinal compounds, icaritin and its derivatives in E. pubescens. Therefore, our results not only provide a good reference genome to conduct further molecular biological studies in Epimedium genus, but also give important clues for synthetic biology and industrial production of related prenylated flavonoids in future.

Polydopamine-Induced Multilevel Engineering of Regenerated Silk Fibroin Fiber for Photothermal Conversion.

Solid photothermal materials with favorable biocompatibility and modifiable mechanical properties demonstrate obvious superiority and growing demand. In this work, polydopamine (PDA) induced functionalization of regenerated silk fibroin (RSF) fibers has satisfactory photothermal conversion ability and flexibility. Based on multilevel engineering, RSF solution containing PDA nanoparticles is wet spun to PDA-incorporating RSF (PDA@RSF) fibers, and then the fibers are coated with PDA via oxidative self-polymerization of dopamine to form PDA@RSF-PDA (PRP) fibers. During the wet spinning process, PDA is to adjust the mechanical properties of RSF by affecting its hierarchical structure. Meanwhile, coated PDA gives the PRP fibers extensive absorption of near-infrared light and sunlight, which is further fabricated into PRP fibrous membranes. The temperature of PRP fibrous membranes can be adjusted and increases to about 50 °C within 360 s under 808 nm laser irradiation with a power density of 0.6 W cm-2 , and PRP fibrous membranes exhibit effective photothermal cytotoxicity both in vitro and in vivo. Under the simulated sunlight, the temperature of PRP fiber increases to more than 200 °C from room temperature and the material can generate 4.5 V voltage when assembled with a differential thermal battery, which means that the material also has the potential for flexible wearable electronic devices.

Reinforcement of Silk Microneedle Patches for Accurate Transdermal Delivery.

Microneedles (MNs) have attracted considerable attention in the pharmaceutical field as a minimally invasive delivery alternative to hypodermic needles. Current material systems of MNs have gradually shifted from metals, ceramics, and silicon to polymer in consideration of toughness and drug loading capacity. Silk fibroin (SF) is considered one of the most promising alternatives because it combines the ability to maintain the activity of biomolecules, adjustable mechanical strength, and excellent biocompatibility. However, the strength and hardness of SF MNs need to be carefully optimized to ensure skin epidermis penetration and controlled drug release, which are rarely explored in reported works. Here, the synergistic effect of glutaraldehyde-based cross-linking and water vapor annealing post-treatment is presented as an effective method to promote the formation of SF molecular networks and the mechanical strength of SF MNs. Moreover, the reinforced MN substrate is coated with a drug-loaded SF layer with low crystallinity. The drug release experiments demonstrate the successful controlled release of rhodamine B, horseradish peroxidase, and tetracycline, which suggests the great potential in the application of vaccine, antibiosis, cosmetology, and so forth.

Distinct Evolutionary Patterns of NBS-Encoding Genes in Three Soapberry Family (Sapindaceae) Species.

Nucleotide-binding site (NBS)-type disease resistance genes (R genes) play key roles in plant immune responses and have co-evolved with pathogens over the course of plant lifecycles. Comparative genomic studies tracing the dynamic evolution of NBS-encoding genes have been conducted using many important plant lineages. However, studies on Sapindaceae species have not been performed. In this study, a discrepant number of NBS-encoding genes were identified in the genomes of Xanthoceras sorbifolium (180), Dinnocarpus longan (568), and Acer yangbiense (252). These genes were unevenly distributed and usually clustered as tandem arrays on chromosomes, with few existed as singletons. The phylogenetic analysis revealed that NBS-encoding genes formed three monophyletic clades, RPW8-NBS-LRR (RNL), TIR-NBS-LRR (TNL), and CC-NBS-LRR (CNL), which were distinguished by amino acid motifs. The NBS-encoding genes of the X. sorbifolium, D. longan, and A. yangbiense genomes were derived from 181 ancestral genes (three RNL, 23 TNL, and 155 CNL), which exhibited dynamic and distinct evolutionary patterns due to independent gene duplication/loss events. Specifically, X. sorbifolium exhibited a "first expansion and then contraction" evolutionary pattern, while A. yangbiense and D. longan exhibited a "first expansion followed by contraction and further expansion" evolutionary pattern. However, further expansion in D. longan was stronger than in A. yangbiense after divergence, suggesting that D. longan gained more genes in response to various pathogens. Additionally, the ancient and recent expansion of CNL genes generated the dominance of this subclass in terms of gene numbers, while the low copy number status of RNL genes was attributed to their conserved functions.

Complete chloroplast genome sequence of Chimonanthus praecox link (Calycanthaceae): an endemic plant species in China.

Chimonanthus praecox, a deciduous shrub tree, is endemic to China and widely cultivated in the world as a popular garden and ornamental plant. Here, we have reported its complete chloroplast genome with a length of 153,181 bp, containing a large single copy (LSC) region of 86,916 bp, a small single copy (SSC) region of 19,767 bp and two identical inverted repeat regions (IRs) of 23,249 bp. The overall GC contents of the plastome were 39.27%. A total of 114 unique genes were successfully annotated consisting of 80 protein-coding genes, 30 tRNA genes and four rRNA genes. Sixteen genes each possessed one intron and three genes had two introns. The ML phylogenetic analysis supports Chimonanthus as sister to Calycanthus. This result will be helpful for genetic breeding and population genetics of C. praecox, DNA barcoding of Chimonanthus, and phylogenetic studies of Calycanthaceae.

Genome-wide analysis of the Brachypodium distachyon (L.) P. Beauv. Hsp90 gene family reveals molecular evolution and expression profiling under drought and salt stresses.

The structure, evolution, and function of heat shock proteins 90 (Hsp90s) have been investigated in great detail in fungi and animals. However, studies on the Hsp90 genes in plants are generally limited. Brachypodium distachyon (L.) P. Beauv., as a model plant for cereal crops, has become a potential biofuel grass. During its long evolution, the Hsp90 gene family in Brachypodium has developed some strategies to cope with adverse environments. How the Hsp90 gene family in Brachypodium evolved in different plant lineages and what its role is in plant responses to drought and salt stresses remains to be elucidated. We used a set of different bioinformatics tools to identify 94 Hsp90 genes from 10 species representing four plant lineages and classified into three subgroups. Eight BdHsp90 genes were detected from B. distachyon. The number of exon-intron structures differed in each subgroup, and the motif analysis revealed that these genes were relatively conservative in each group. The fragments duplication and tandem duplication, which are the prime powers for functional diversity, generally occurred during the duplication of the whole plant genome. Transcriptional analysis of the BdHsp90 genes under salt and drought stress conditions indicated that the expression of these genes was delayed or increased at different stress time points; The expression was more affected in that of Bradi3g39630, Bradi4g06370, and Bradi1g30130. Our findings suggest the involvement of BdHsp90s in plant abiotic stress response, and further consolidate our views on the stress response mechanism of Hsp90 in general.

Metal-free I2O5-mediated direct construction of sulfonamides from thiols and amines.

A simple and convenient method has been developed for the construction of sulfonamides via I2O5-mediated sulfonylation of amines with arylthiols. The present protocol provides an attractive approach to sulfonamides in moderate to good yields from readily accessible and easy to handle starting materials under mild and metal-free conditions.

A Reactive (1)O2 - Responsive Combined Treatment System of Photodynamic and Chemotherapy for Cancer.

The development of reactive oxygen species (ROS)-responsive drug delivery and drug release has gradually attracted much attention in recent years as a promising therapeutic strategy. Singlet oxygen ((1)O2) as the major ROS species is widely used in photodynamic therapy (PDT) of cancer. In the present study, we introduce a combined treatment using ROS-sensitive thioketal (TK) linkage as a linker between upconversion nanoparticles (UNs)-based PDT and doxorubicin (DOX)-based chemotherapy. UNs can not only play a role in PDT, but can also be used as a nanocarrier for drug delivery of DOX. Moreover, the products of (1)O2 during PDT are able to cleave TK linker inducing the release of DOX which can further achieve the goal of chemotherapy. By using this (1)O2-responsive nanocarrier delivery system, DOX can easily reach the tumor site and be accumulated in the nuclei to effectively kill the cancer cells, and therefore decreasing the side effects of chemotherapy on the body. Thus, PDT also has the function of controlling drug release in this combination treatment strategy. Compared with monotherapy, the combination of PDT with chemotherapy also possesses excellent drug loading capability and anticancer efficiency.