Reaction of N‐heterocyclic carbene (NHC)‐stabilized PGeP‐type germylene Ge{o‐(PiPr2)C6H4}2⋅MeIiPr (1) (MeIiPr=1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) with Ni(cod)2 gave pincer germylene ...complex NiGe{o‐(PiPr2)C6H4}2(MeIiPr) (2), in which the Ge center of 2 is significantly pyramidalized. Theoretical calculation on 2 predicted the ambiphilicity of the germanium center, which was confirmed by reactivity studies. Thus, complex 2 reacted with both Lewis base MeIMe (MeIMe=1,3,4,5‐tetramethylimidazol‐2‐ylidene) and Lewis acid BH3⋅SMe2 at the germanium center to afford the adducts NiGe{o‐(PiPr2)C6H4}2⋅MeIMe(MeIiPr) (3) and NiGe{o‐(PiPr2)C6H4}2⋅BH3(MeIiPr) (4), respectively. Furthermore, the former was slowly converted to dinuclear complex Ni2Ge{o‐(PiPr2)C6H4}22(MeIMe)2 (5) at room temperature. Complex 5 can be regarded as a dimer of the MeIMe analog of 2 with a Ni‐Ge‐Ge‐Ni linkage.
A nickel pincer germylene complex with a pyramidalized germanium center was synthesized. Theoretical calculation predicted the germanium center to be ambiphilic (electrophilic and nucleophilic), which was confirmed by reactions with Lewis base and Lewis acid. The former adduct was converted to a dinuclear complex with a Ni‐Ge‐Ge‐Ni linkage through Ge−Ge coupling between germylene ligands.
Parthenocarpy in horticultural crop plants is an important trait with agricultural value for various industrial purposes as well as direct eating quality. Here, we demonstrate a breeding strategy to ...generate parthenocarpic tomato plants using the CRISPR/Cas9 system. We optimized the CRISPR/Cas9 system to introduce somatic mutations effectively into SlIAA9-a key gene controlling parthenocarpy-with mutation rates of up to 100% in the T0 generation. Furthermore, analysis of off-target mutations using deep sequencing indicated that our customized gRNAs induced no additional mutations in the host genome. Regenerated mutants exhibited morphological changes in leaf shape and seedless fruit-a characteristic of parthenocarpic tomato. And the segregated next generation (T1) also showed a severe phenotype associated with the homozygous mutated genome. The system developed here could be applied to produce parthenocarpic tomato in a wide variety of cultivars, as well as other major horticultural crops, using this precise and rapid breeding technique.
Reaction of NHC-stabilized dichlorogermylenes (NHC = N-heterocyclic carbene) with an anionic tungsten complex produced NHC-stabilized chlorometallogermylenes. Subsequent chloride abstraction from the ...products with NaBAr4 (Ar = 3,5-(CF3)2C6H3) gave a cationic metallogermylene or dicationic dimetallodigermenes.
A peptide-type covalent binder for a target protein was obtained by direct and stringent screening of a warhead-modified peptide library on the robust T7 phage. The aryl fluorosulfate (fosylate) ...warhead was activated only in a matchmaking microenvironment created between the target protein and an appropriate peptide during the reactivity/affinity-based co-selection process of extended phage display.
To find targeted covalent biologics, we demonstrated a direct screening method of a peptidic covalent binder
via
reactivity/affinity-based co-selection using T7 phage display.
Insect body colors and patterns change markedly during development in some species as they adapt to their surroundings. The contribution of melanin and sclerotin pigments, both of which are ...synthesized from dopamine, to cuticle tanning has been well studied. Nevertheless, little is known about how insects alter their body color patterns. To investigate this mechanism, the cricket Gryllus bimaculatus, whose body color patterns change during postembryonic development, was used as a model in this study. We focused on the ebony and tan genes, which encode enzymes that catalyze the synthesis and degradation, respectively, of the precursor of yellow sclerotin N-β-alanyl dopamine (NBAD). Expression of the G. bimaculatus (Gb) ebony and tan transcripts tended to be elevated just after hatching and the molting period. We found that dynamic alterations in the combined expression levels of Gb'ebony and Gb'tan correlated with the body color transition from the nymphal stages to the adult. The body color of Gb'ebony knockout mutants generated by CRISPR/Cas9 systemically darkened. Meanwhile, Gb'tan knockout mutants displayed a yellow color in certain areas and stages. The phenotypes of the Gb'ebony and Gb'tan mutants probably result from an over-production of melanin and yellow sclerotin NBAD, respectively. Overall, stage-specific body color patterns in the postembryonic stages of the cricket are governed by the combinatorial expression of Gb'ebony and Gb'tan. Our findings provide insights into the mechanism by which insects evolve adaptive body coloration at each developmental stage.
Microwave-assisted pretreatment of recalcitrant softwood in aqueous glycerol containing a series of organic and inorganic acids with different
pK
a
values was examined. The pulp obtained by ...organosolvolysis with 0.1% hydrochloric acid (
pK
a
−6) at 180
°C for 6
min gave the highest sugar yield, 53.1%, based on the weight of original biomass. The pretreatment efficiency correlated linearly with the
pK
a
of the acids, with the exception of malonic and phosphoric acids. Organosolvolysis with 1.0% phosphoric acid (
pK
a
2.15) gave a saccharification yield (50.6%) higher than that expected from its
pK
a
, while the catalytic effect of malonic acid (
pK
a
2.83) was negligible. Extensive exposure of crystalline and non-crystalline cellulose by the glycerolysis with strong inorganic acids was demonstrated by using fluorescent-labeled recombinant carbohydrate-binding modules (CBMs). Because of the low concentration of the acid catalysts and availability of glycerol as a by-product from biodiesel and fatty acid production, organosolvolysis in glycerol is an appealing process for pretreatment of recalcitrant softwood.
Abstract Most of our knowledge of insect genomes comes from Holometabolous species, which undergo complete metamorphosis and have genomes typically under 2 Gb with little signs of DNA methylation. In ...contrast, Hemimetabolous insects undergo the presumed ancestral process of incomplete metamorphosis, and have larger genomes with high levels of DNA methylation. Hemimetabolous species from the Orthopteran order (grasshoppers and crickets) have some of the largest known insect genomes. What drives the evolution of these unusual insect genome sizes, remains unknown. Here we report the sequencing, assembly and annotation of the 1.66-Gb genome of the Mediterranean field cricket Gryllus bimaculatus , and the annotation of the 1.60-Gb genome of the Hawaiian cricket Laupala kohalensis . We compare these two cricket genomes with those of 14 additional insects and find evidence that hemimetabolous genomes expanded due to transposable element activity. Based on the ratio of observed to expected CpG sites, we find higher conservation and stronger purifying selection of methylated genes than non-methylated genes. Finally, our analysis suggests an expansion of the pickpocket class V gene family in crickets, which we speculate might play a role in the evolution of cricket courtship, including their characteristic chirping.
Hemimetabolous, or incompletely metamorphosing, insects are phylogenetically relatively basal and comprise many pests. However, the absence of a sophisticated genetic model system, or targeted ...gene-manipulation system, has limited research on hemimetabolous species. Here we use zinc-finger nuclease and transcription activator-like effector nuclease technologies to produce genetic knockouts in the hemimetabolous insect Gryllus bimaculatus. Following the microinjection of mRNAs encoding zinc-finger nucleases or transcription activator-like effector nucleases into cricket embryos, targeting of a transgene or endogenous gene results in sequence-specific mutations. Up to 48% of founder animals transmit disrupted gene alleles after zinc-finger nucleases microinjection compared with 17% after microinjection of transcription activator-like effector nucleases. Heterozygous offspring is selected using mutation detection assays that use a Surveyor (Cel-I) nuclease, and subsequent sibling crosses create homozygous knockout crickets. This approach is independent from a mutant phenotype or the genetic tractability of the organism of interest and can potentially be applied to manage insect pests using a non-transgenic strategy.
To develop an augmentative biological control programme for
Bemisia tabaci
(Gennadius) (Hemiptera: Aleyrodidae) and
Thrips palmi
Karny (Thysanoptera: Thripidae) using
Nesidiocoris tenuis
(Reuter) ...(Hemiptera: Miridae), we studied the life history traits of a Japanese strain of
N. tenuis
reared on
B. tabaci
and
T. palmi
in controlled environments. The lower developmental threshold during the nymphal period was far higher than those estimated for Spanish, Moroccan, and Iranian strains, indicating that the Japanese strain is better adapted to higher temperatures than the other three strains tested. The intrinsic rate of increase
r
m
was highest at 30 °C and lowest at 20 °C. The
r
m
value for individuals reared on
T. palmi
at 25 °C was lower than that for individuals reared on
B. tabaci
at the same temperature. Implications of these results for the biological control of
B. tabaci
and
T. palmi
in greenhouses are discussed.
The longhorned beetle Aromia bungii (Coleoptera: Cerambycidae) is a major pest of stone fruit trees in the genus Prunus, including cherries, apricots, and peaches. Its native range includes China, ...Korea, Mongolia, and eastern Russia, but it has recently invaded and become established in several countries in Europe, and Japan, and it has been intercepted in shipments coming into North America and Australia. Here, we report the identification of its male-produced aggregation pheromone as the novel compound (E)-2-cis-6,7-epoxynonenal. In field trials in its native range in China, and in recently invaded areas of Japan, the pheromone attracted both sexes of the beetle. Thus, the pheromone should find immediate use in worldwide quarantine surveillance efforts to detect the beetle in incoming shipments. The pheromone will also be a crucial tool in ongoing efforts to eradicate the beetle from regions of the world that it has already invaded.
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