Ultrathin Bilayer of Graphite/SiO2 as Solid Interface for Reviving Li Metal Anode

Lithium metal anodes are expected to drive practical applications that require high energy‐density storage. However, the direct use of metallic lithium causes safety concerns, low rate capabilities, and poor cycling performance due to unstable solid electrolyte interphase (SEI) and undesired lithium dendrite growth. To address these issues, a radio frequency sputtered graphite‐SiO₂ ultrathin bilayer on a Li metal chips is demonstrated, for the first time, as an effective SEI layer. This leads to a dendrite free uniform Li deposition to achieve a stable voltage profile and outstanding long hours plating/stripping compared to the bare Li. Compared to a bare Li anode, the graphite‐SiO₂ bilayer modified Li anode coupled with lithium nickel cobalt manganese oxide cathode (NMC111) and lithium titanate shows improved capacity retention, higher capacity at higher rates, longer cycling stability, and lower voltage hysteresis. Graphite acts as an electrical bridge between the plated Li and Li electrode, which lowers the impedance and buffers the volume expansion during Li plating/stripping. Adding an ultrathin SiO₂ layer facilitates Li‐ion diffusion and lithiation/delithiation, provides higher electrolyte affinity, higher chemical stability, and higher Young's modulus to suppress the Li dendrite growth.     

Biomass yield in a genetically diverse Miscanthus sinensis germplasm panel evaluated at five locations revealed individuals with exceptional potential

To breed improved biomass cultivars of Miscanthus ×giganteus, it will be necessary to select the highest‐yielding and best‐adapted genotypes of its parental species, Miscanthus sinensis and Miscanthus sacchariflorus. We phenotyped a diverse clonally propagated panel of 569 M. sinensis and nine natural diploid M. ×giganteus at one subtropical (Zhuji, China) and five temperate locations (Sapporo, Japan; Leamington, Ontario, Canada; Fort Collins, CO; Urbana, IL; and Chuncheon, Korea) for dry biomass yield and 14 yield‐component traits, in trials grown for 3 years. Notably, dry biomass yield of four Miscanthus accessions exceeded 80 Mg/ha in Zhuji, China, approaching the highest observed for any land plant. Additionally, six M. sinensis in Sapporo, Japan and one in Leamington, Canada also yielded more than the triploid M. ×giganteus ‘1993‐1780’ control, with values exceeding 20 Mg/ha. Diploid M. ×giganteus was the best‐yielding group at the northern sites. Genotype‐by‐environment interactions were modest among the five northern trial sites but large between Zhuji, and the northern sites. M. sinensis accessions typically yielded best at trial sites with latitudes similar to collection sites, although broad adaptation was observed for accessions from southern Japan. Genotypic heritabilities for third year yields ranged from 0.71 to 0.88 within locations. Compressed circumference was the best predictor of yield. These results establish a baseline of data for initiating selection to improve biomass yield of M. sinensis and M. ×giganteus in a diverse set of relevant geographies.     

Genome‐wide association and genomic prediction for biomass yield in a genetically diverse Miscanthus sinensis germplasm panel phenotyped at five locations in Asia and North America

To improve the efficiency of breeding of Miscanthus for biomass yield, there is a need to develop genomics‐assisted selection for this long‐lived perennial crop by relating genotype to phenotype and breeding value across a broad range of environments. We present the first genome‐wide association (GWA) and genomic prediction study of Miscanthus that utilizes multilocation phenotypic data. A panel of 568 Miscanthus sinensis accessions was genotyped with 46,177 single nucleotide polymorphisms (SNPs) and evaluated at one subtropical and five temperate locations over 3 years for biomass yield and 14 yield‐component traits. GWA and genomic prediction were performed separately for different years of data in order to assess reproducibility. The analyses were also performed for individual field trial locations, as well as combined phenotypic data across groups of locations. GWA analyses identified 27 significant SNPs for yield, and a total of 504 associations across 298 unique SNPs across all traits, sites, and years. For yield, the greatest number of significant SNPs was identified by combining phenotypic data across all six locations. For some of the other yield‐component traits, greater numbers of significant SNPs were obtained from single site data, although the number of significant SNPs varied greatly from site to site. Candidate genes were identified. Accounting for population structure, genomic prediction accuracies for biomass yield ranged from 0.31 to 0.35 across five northern sites and from 0.13 to 0.18 for the subtropical location, depending on the estimation method. Genomic prediction accuracies of all traits were similar for single‐location and multilocation data, suggesting that genomic selection will be useful for breeding broadly adapted M. sinensis as well as M. sinensis optimized for specific climates. All of our data, including DNA sequences flanking each SNP, are publicly available. By facilitating genomic selection in M. sinensis and Miscanthus × giganteus, our results will accelerate the breeding of these species for biomass in diverse environments.     

Improved Squalene Production via Modulation of the Methylerythritol 4-Phosphate Pathway and Heterologous Expression of Genes from Streptomyces peucetius ATCC 27952 in Escherichia coli

Putative hopanoid genes from Streptomyces peucetius were introduced into Escherichia coli to improve the production of squalene, an industrially important compound. High expression of hopA and hopB (encoding squalene/phytoene synthases) together with hopD (encoding farnesyl diphosphate synthase) yielded 4.1 mg/liter of squalene. This level was elevated to 11.8 mg/liter when there was also increased expression of dxs and idi, E. coli genes encoding 1-deoxy-d-xylulose 5-phosphate synthase and isopentenyl diphosphate isomerase.Squalene, an industrially important compound obtained primarily from the liver oil of deep-sea sharks and whales, is an important ingredient in skin cosmetics due to its photoprotective role (2, 7). The decreased cancer risk associated with high olive oil consumption could result from high squalene content (12, 16). Squalene has a chemopreventive effect on colon cancer (14). Moreover, squalene has wide applications in fine chemicals, magnetic tape, and low-temperature lubricants and as an additive in animal feed (1).The use of shark liver oil is limited, due to the presence of environmental pollutants, such as polychlorinated biphenyls, heavy metals, and methylmercury residues, as well as an unpleasant fishy odor and taste (17, 19). Moreover, the presence of similar compounds, such as cholesterol, in the oils from marine animal liver can make squalene purification difficult. In addition, squalene production is limited by uncertain availability because of international concern for the protection of marine animals. Squalene has also been obtained from plant sources (4, 10, 11, 18), but very few methods can produce sufficient quantities at the desired purity level for pharmaceutical and industrial applications (6). The use of engineered microbial cell factories for the biosynthesis of squalene may be a suitable alternative to address these issues.In the genome project for Streptomyces peucetius ATCC 27952, a cluster of genes which comprises five open reading frames, encoding hopanoid biosynthesis, has been detected and annotated. Even though these open reading frames share sequence homology with genes involved in hopanoid biosynthesis, no plausible hopanoid products have been isolated from S. peucetius in all laboratory cultures. Therefore, the hopanoid biosynthetic gene cluster of S. peucetius was considered “cryptic” in the present study. We were interested in activating the so-called “cryptic” hopanoid biosynthetic gene cluster of S. peucetius to produce pharmaceutically important compounds by using genetic engineering tools. Isoprenoid production in Escherichia coli has been extensively studied and reviewed (5, 8, 9, 15, 20, 21), but very few reports detail squalene formation in E. coli by the use of exogenous genes (13). In the present study, we introduced three cryptic genes (hopABD) from the hopanoid biosynthesis gene cluster from S. peucetius that catalyzed squalene production and also modulated the 2-C-methyl-d-erythritol 4-phosphate pathway in E. coli to enhance squalene production (Fig. ​(Fig.11).Open in a separate windowFIG. 1.Schematic representation of the engineered squalene biosynthetic pathway in E. coli BL21(DE3). DXS and IDI were overexpressed for the modulation of the MEP pathway to increase and balance the IPP pool, HopD (farnesyl diphosphate synthase) was overexpressed to increase FPP, and HopA and HopB (HopAB) (squalene synthases) were overexpressed to overproduce squalene. The recombinant enzymes overexpressed in E. coli are boxed.     

Genome-wide association and genomic prediction for yield and component traits of Miscanthus sacchariflorus

Accelerating biomass improvement is a major goal of Miscanthus breeding. The development and implementation of genomic-enabled breeding tools, like marker-assisted selection (MAS) and genomic selection, has the potential to improve the efficiency of Miscanthus breeding. The present study conducted genome-wide association (GWA) and genomic prediction of biomass yield and 14 yield-components traits in Miscanthus sacchariflorus. We evaluated a diversity panel with 590 accessions of M. sacchariflorus grown across 4 years in one subtropical and three temperate locations and genotyped with 268,109 single-nucleotide polymorphisms (SNPs). The GWA study identified a total of 835 significant SNPs and 674 candidate genes across all traits and locations. Of the significant SNPs identified, 280 were localized in mapped quantitative trait loci intervals and proximal to SNPs identified for similar traits in previously reported Miscanthus studies, providing additional support for the importance of these genomic regions for biomass yield. Our study gave insights into the genetic basis for yield-component traits in M. sacchariflorus that may facilitate marker-assisted breeding for biomass yield. Genomic prediction accuracy for the yield-related traits ranged from 0.15 to 0.52 across all locations and genetic groups. Prediction accuracies within the six genetic groupings of M. sacchariflorus were limited due to low sample sizes. Nevertheless, the Korea/NE China/Russia (N = 237) genetic group had the highest prediction accuracy of all genetic groups (ranging 0.26–0.71), suggesting that with adequate sample sizes, there is strong potential for genomic selection within the genetic groupings of M. sacchariflorus. This study indicated that MAS and genomic prediction will likely be beneficial for conducting population-improvement of M. sacchariflorus.     

Adsorption study of metal ions onto crosslinked seaweed Laminaria japonica

An efficient and cost effective non-conventional adsorbent has been prepared from seaweed Laminaria japonica by crosslinking with epichlorohydrin. Its adsorption behavior for trivalent and divalent metal ions was studied and it was found to exhibit excellent selectivity towards several metal ions. As a typical example, binary mixture of Pb(II) and Zn(II) was studied by using a packed column, indicating that the Pb(II) ion can be easily separated from its mixture with a concentration factor of 74 times. The maximum adsorption capacity for Pb(II), Cd(II), Fe(III) was found to be 1.35, 1.1, 1.53 mol kg(-1), respectively, while 0.8 7 mol kg(-1) for both La(III) and Ce(III) from the single metal ion solution according to the adsorption isotherm. The obtained values are comparable to the commercially available synthetic chelating resins.     

Regeneration of bacteriorhodopsin from thermally unfolded bacterio-opsin and all-trans retinal at high temperatures

The temperature dependence of regeneration of bacteriorhodopsin (bR) from its apoprotein, bacterio-opsin (bO), and all-trans retinal was investigated using two different procedures to probe the structural properties of bO at high temperatures. Regeneration experiments performed at 25 degrees C after incubation of bO within the temperature range of 35-75 degrees C indicate that irreversible thermal unfolding begins at 50 degrees C. When bO is incubated for one hour and mixed with retinal at the same elevated temperatures, however, a greater extent of regeneration to bR occurs, even at temperatures ranging from 50 to 65 degrees C. These experimental results indicate that regeneration of bR occurs from thermally unfolded bO and suggest dynamic structural fluctuation of bO in the unfolded state.     

Host finding by Uscana lariophaga (Hymenoptera: Trichogrammatidae) in stored cowpea: the effect of distance, time interval, host patch size and spatial orientation

Host finding and parasitization by Uscana lariophaga Steffan, a potential biocontrol agent of the storage pest Callosobruchus maculatus (Fabricius), were investigated in stored cowpea. Host finding was shown to be a function of distance, time, host patch size and the spatial position of U. lariophaga relative to the host patch. Uscana lariophaga females were able to find hosts up to 75 cm horizontal distance from the host patch, which was the largest distance tested. The probability that a host patch was found when an individual U. lariophaga female was released at 2.5 cm horizontal distance from the host patch ranged from 0.6 after 2 h foraging time to 0.9 after 8 h foraging time. At 10 cm from the host patch, host finding probability ranged from 0.2 to 0.45 at these respective foraging times. Finding probabilities doubled compared to horizontal distances when U. lariophaga was released below the host patch, and halved when it was released above the host patch. The negative geotaxic response was shown not to be an artefact of the release method. The median net displacement rate in the direction of the host patch was two beans per hour (1.4 cm h(-1)). The results suggest that U. lariophaga females start searching for hosts regardless of the quality of the olfactory information they receive. Additional observations indicated that U. lariophaga is adapted to a host with a patchy distribution, which implies that host finding over larger distances is relevant for U. lariophaga.     

High-frequency direct shoot regeneration from <Emphasis Type="Italic">Drymaria cordata</Emphasis> Willd. leaves

An efficient and reproducible procedure is described for direct shoot regeneration in Drymaria cordata Willd. using leaf explants cultured on Murashige and Skoog (MS) medium supplemented with α-naphthalene acetic acid (NAA) and 6-benzyladenine. The regeneration frequency varied with the plant growth regulator concentrations, orientation of the explants, and the carbon source and basal salts present in the regeneration medium. The highest mean number of shoots per explant (10.65 ± 1.03) was recorded on MS plates containing 3% sucrose and 0.8% agar supplemented with 0.1 mg/l NAA and 1.0 mg/l BAP. Shoot buds were induced in the basal parts of the leaf explants. Concentrations of NAA exceeding 1 mg/l suppressed shoot regeneration. Explants bearing the entire lamina and petiole were much more responsive than those having only the lamina. The plantlets that regenerated from the leaf explants were rooted successively on MS medium alone or in combination with indole butyric acid (IBA). The highest mean number of root organogenesis, with 25.67 ± 3.68 roots per leaf segment, was obtained in the presence of 1 mg/l IBA. Histological investigations of the regenerating shoots showed that the shoot buds had emerged from epidermal cells without callus formation. More than 90% of the in vitro-propagated plants survived when transferred to a greenhouse for acclimatization. Thus, this optimized regeneration system may be used for rapid shoot proliferation and genetic transformation.