Changes in the rhizosphere and root-associated bacteria community of white Guinea yam (Dioscorea rotundata Poir.) impacted by genotype and nitrogen fertilization.

The bacterial diversity and composition of water yam (Dioscorea alata L. cv. A-19), which can grow without chemical fertilization, have recently been characterized with no significant differences compared with the use of chemical fertilization. However, the diversity and community structure of bacteria associated with the white Guinea yam (Dioscorea rotundata), the most cultivated and economically important yam in West Africa, have not yet been investigated. This study characterized the bacterial diversity and composition associated with bulk soil, rhizosphere, and plant roots in six white Guinea yam genotypes (S004, S020, S032, S042, S058, and S074) in field experiments in Ibadan, Nigeria under N-based chemical fertilizer application. The largest diversity of bacteria was found in the bulk soil, followed by the rhizosphere and roots. Based on the alpha diversity analysis, the bacterial diversity in both S020 and S042 increased with fertilizer application among the bulk soil samples. S058 grown under no-fertilizer conditions had the highest bacterial diversity among the rhizosphere samples. Beta diversity analysis highlighted the significant difference in the composition of bacteria associated with the genotypes and fertilizer treatments, and S032 had a unique bacterial composition compared to the other genotypes. The dominant phylum across all sample types was Proteobacteria. Actinobacteriota was the dominant phylum among bulk soil samples. At the genus level, Bacillus was the most abundant bacterial genus across both the control and treated samples. Pseudomonas was predominant across all rhizosphere samples. Chryseobacterium, Sphingobium, Delftia and Klebsiella associated with the rhizosphere were shown the altered relative abundance between the control and treated samples depending on genotypes. A genus related to symbiotic nitrogen-fixing bacteria, the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade, showed higher relative abundance among all root samples, indicating that it is a core bacterial genus. Furthermore, the field application of chemical fertilizer had a significant impact on the relative abundances of two genera related to symbiotic nitrogen-fixers, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade and Bradyrhizobium in the rhizosphere and root. These results suggest that N-based chemical fertilizers and plant genotypes would influence the compositional arrangement of associated bacterial communities, including symbiotic nitrogen-fixing bacteria.

One-pot C(sp3)-H difluoroalkylation of tetrahydroisoquinolines and isochromans via electrochemical oxidation and organozinc alkylation.

The C(sp3)-H difluoroalkylation for the introduction of carbonylated CF2 groups into tetrahydroisoquinolines (THIQs) and isochromans has been achieved by using electrochemical oxidation and organozinc alkylation. This one-pot process proceeded smoothly under transition-metal catalyst- and chemical oxidant-free conditions, and the desired products were obtained in good to high yields with a broad scope, except for N-Boc-THIQ. In addition, the gram-scale experiment successfully demonstrated the promising scalability. This is the first example of an electrochemical method for C(sp3)-H difluoroalkylation of amines and ethers.

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation.

The radical hydroarylation of alkenes is an efficient strategy for accessing linear alkylarenes with high regioselectivity. Herein, we report the electroreductive hydroarylation of electron-deficient alkenes and styrene derivatives using (hetero)aryl halides under mild reaction conditions. Notably, the present hydroarylation proceeded with high efficiency under transition-metal-catalyst-free conditions. The key to success is the use of 1,3-dicyanobenzene as a redox mediator and visible-light irradiation, which effectively suppresses the formation of simple reduction, i.e., hydrodehalogenation, products to afford the desired products in good to high yields. Mechanistic investigations proposed that a reductive radical-polar crossover pathway is likely to be involved in this transformation.

Synthesis of ω-Chloroalkyl Aryl Ketones via C-C Bond Cleavage of tert-Cycloalkanols with Tetramethylammonium Hypochlorite.

An oxidative C-C bond cleavage of tert-cycloalkanols with tetramethylammonium hypochlorite (TMAOCl) has been developed. TMAOCl is easy to prepare from tetramethylammonium hydroxide, and the combination of TMAOCl and AcOH effectively promoted the C-C bond cleavage in a two-phase system without additional phase-transfer reagents. Unstrained tert-cycloalkanols were transformed into ω-chloroalkyl aryl ketones in moderate to excellent yields under metal-free and mild reaction conditions.

Sensing chemical-induced DNA damage using CRISPR/Cas9-mediated gene-deletion yeast-reporter strains.

Microorganism-based genotoxicity assessments are vital for evaluating potential chemical-induced DNA damage. In this study, we developed both chromosomally integrated and single-copy plasmid-based reporter assays in budding yeast using a RNR3 promoter-driven luciferase gene. These assays were designed to compare the response to genotoxic chemicals with a pre-established multicopy plasmid-based assay. Despite exhibiting the lowest luciferase activity, the chromosomally integrated reporter assay showed the highest fold induction (i.e., the ratio of luciferase activity in the presence and absence of the chemical) compared with the established plasmid-based assay. Using CRISPR/Cas9 technology, we generated mutants with single- or double-gene deletions, affecting major DNA repair pathways or cell permeability. This enabled us to evaluate reporter gene responses to genotoxicants in a single-copy plasmid-based assay. Elevated background activities were observed in several mutants, such as mag1Δ cells, even without exposure to chemicals. However, substantial luciferase induction was detected in single-deletion mutants following exposure to specific chemicals, including mag1Δ, mms2Δ, and rad59Δ cells treated with methyl methanesulfonate; rad59Δ cells exposed to camptothecin; and mms2Δ and rad10Δ cells treated with mitomycin C (MMC) and cisplatin (CDDP). Notably, mms2Δ/rad10Δ cells treated with MMC or CDDP exhibited significantly enhanced luciferase induction compared with the parent single-deletion mutants, suggesting that postreplication and for nucleotide excision repair processes predominantly contribute to repairing DNA crosslinks. Overall, our findings demonstrate the utility of yeast-based reporter assays employing strains with multiple-deletion mutations in DNA repair genes. These assays serve as valuable tools for investigating DNA repair mechanisms and assessing chemical-induced DNA damage. KEY POINTS: • Responses to genotoxic chemicals were investigated in three types of reporter yeast. • Yeast strains with single- and double-deletions of DNA repair genes were tested. • Two DNA repair pathways predominantly contributed to DNA crosslink repair in yeast.

(3+2) Cycloaddition of Heteroaromatic N-Ylides with Sulfenes.

A (3+2) cycloaddition of heteroaromatic N-ylides with sulfenes, which are generated in situ from sulfonyl chlorides, has been developed. A variety of ylides were transformed into the corresponding sulfone-embedded N-fused heterocycles in high yields. Hexafluoroisopropyl mesylate was demonstrated to be a suitable reactant for quinolinium ylides. Furthermore, this cycloaddition could be performed with an ylide prepared by a Cu-catalyzed ylide transfer reaction in a one-pot manner, extending the substrate scope to an unisolable ylide.

Noxious chemical discrimination by Tribolium castaneum TRPA1 channel in the HEK293 cell expression system.

Nociception is the sensory perception of noxious chemical stimuli. Repellent behavior to avoid noxious stimuli is indispensable for survival, and this mechanism has been evolutionarily conserved across a wide range of species, from mammals to insects. The transient receptor potential ankyrin 1 (TRPA1) channel is one of the most conserved noxious chemical sensors. Here, we describe the heterologous stable expression of Tribolium castaneum TRPA1 (TcTRPA1) in human embryonic kidney (HEK293) cells. The intracellular Ca2+ influx was measured when two compounds, citronellal and l-menthol, derived from plant essential oils, were applied in vitro using a fluorescence assay. The analysis revealed that citronellal evoked Ca2+ influx dose-dependently for TcTRPA1, whereas l-menthol did not. In combination with our present and previous results of the avoidance-behavioral assay at the organism level, we suggest that TcTRPA1 discriminates between these two toxic compounds, and diversification in the chemical nociception selectivity has occurred in TRPA1 channel among insect taxa.

Risk Factors for Infusion Reactions in Patients with Breast Cancer Administered Trastuzumab Therapy.

Trastuzumab is a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) that is indicated for the treatment of HER2-positive breast cancer. The administration of biologics, such as trastuzumab, frequently causes infusion reactions (IRs) with fever and chills. This study aimed to clarify the risk factors for IRs in trastuzumab therapy. Between March 2013 and July 2022, 227 patients with breast cancer who started trastuzumab therapy were included in this study. The severity of IRs was graded according to the Common Terminology Criteria for Adverse Events, Version 5.0. The incidence of IRs in trastuzumab therapy was 27.3% (62/227). Dexamethasone administration was significantly different between the IR and non-IR groups in patients receiving trastuzumab therapy (univariate analysis, p < 0.001; multivariate analysis, p = 0.0002). Without dexamethasone, the severity of IRs in the pertuzumab combination group (Grade 1, 8/65; Grade 2, 23/65) was significantly higher than that in the non-pertuzumab group (Grade 1, 9/37; Grade 2, 3/37; p < 0.05). Our findings suggest that the risk of IRs is significantly higher in patients not premedicated with dexamethasone in trastuzumab therapy and that the concomitant use of pertuzumab without dexamethasone increases the severity of IRs caused by trastuzumab.

Hyphal Growth in Trichosporon asahii Is Accelerated by the Addition of Magnesium.

Fungal dimorphism involves two morphologies: a unicellular yeast cell and a multicellular hyphal form. Invasion of hyphae into human cells causes severe opportunistic infections. The transition between yeast and hyphal forms is associated with the virulence of fungi; however, the mechanism is poorly understood. Therefore, we aimed to identify factors that induce hyphal growth of Trichosporon asahii, a dimorphic basidiomycete that causes trichosporonosis. T. asahii showed poor growth and formed small cells containing large lipid droplets and fragmented mitochondria when cultivated for 16 h in a nutrient-deficient liquid medium. However, these phenotypes were suppressed via the addition of yeast nitrogen base. When T. asahii cells were cultivated in the presence of different compounds present in the yeast nitrogen base, we found that magnesium sulfate was a key factor for inducing cell elongation, and its addition dramatically restored hyphal growth in T. asahii. In T. asahii hyphae, vacuoles were enlarged, the size of lipid droplets was decreased, and mitochondria were distributed throughout the cell cytoplasm and adjacent to the cell walls. Additionally, hyphal growth was disrupted due to treatment with an actin inhibitor. The actin inhibitor latrunculin A disrupted the mitochondrial distribution even in hyphal cells. Furthermore, magnesium sulfate treatment accelerated hyphal growth in T. asahii for 72 h when the cells were cultivated in a nutrient-deficient liquid medium. Collectively, our results suggest that an increase in magnesium levels triggers the transition from the yeast to hyphal form in T. asahii. These findings will support studies on the pathogenesis of fungi and aid in developing treatments. IMPORTANCE Understanding the mechanism underlying fungal dimorphism is crucial to discern its invasion into human cells. Invasion is caused by the hyphal form rather than the yeast form; therefore, it is important to understand the mechanism of transition from the yeast to hyphal form. To study the transition mechanism, we utilized Trichosporon asahii, a dimorphic basidiomycete that causes severe trichosporonosis since there are fewer studies on T. asahii than on ascomycetes. This study suggests that an increase in Mg2+, the most abundant mineral in living cells, triggers growth of filamentous hyphae and increases the distribution of mitochondria throughout the cell cytoplasm and adjacent to the cell walls in T. asahii. Understanding the mechanism of hyphal growth triggered by Mg2+ increase will provide a model system to explore fungal pathogenicity in the future.

Replacement of water yam (Dioscorea alata L.) indigenous root endophytes and rhizosphere bacterial communities via inoculation with a synthetic bacterial community of dominant nitrogen-fixing bacteria.

Biofertilizers containing high-density plant growth-promoting bacteria are gaining interest as a sustainable solution to environmental problems caused by eutrophication. However, owing to the limitations of current investigative techniques, the selected microorganisms are not always preferred by the host plant, preventing recruitment into the native microbiota or failing to induce plant growth-promoting effects. To address this, five nitrogen-fixing bacteria previously isolated from water yam (Dioscorea alata L.) plants and showing dominant abundance of 1% or more in the water yam microbiota were selected for analysis of their plant growth-promoting activities when used as a synthetic bacterial inoculant. Water yam cv. A-19 plants were inoculated twice at 10 and 12 weeks after planting under greenhouse conditions. Bacterial communities in root, rhizosphere, and bulk soil samples were characterized using high-throughput 16S rRNA amplicon sequencing. Compared with non-inoculated plants, all bacterial communities were significantly altered by inoculation, mainly at the genus level. The inoculation effects were apparently found in the root communities at 16 weeks after planting, with all inoculated genera showing dominance (in the top 35 genera) compared with the control samples. However, no significant differences in any of the growth parameters or nitrogen contents were observed between treatments. At 20 weeks after planting, the dominance of Stenotrophomonas in the inoculated roots decreased, indicating a decline in the inoculation effects. Interestingly, only the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade was dominant (>1% relative abundance) across all samples, suggesting that bacteria related to this clade are essential core bacteria for water yam growth. This is the first report on addition of a synthetic nitrogen-fixing bacterial community in water yam plants showing that native bacterial communities can be replaced by a synthetic bacterial community, with declining in the effects of Stenotrophomonas on the modified communities several weeks after inoculation.

Incidence and risk factors of infusion reactions in patients with breast cancer administered trastuzumab plus pertuzumab-based regimen.

PURPOSE: Pertuzumab (Per) is a humanized monoclonal antibody used in combination with trastuzumab (Tra) in the treatment of human epidermal growth factor receptor-2 (HER2)-positive breast cancer. The administration of biologics, such as Tra and Per, frequently causes infusion reactions (IRs) with fever and chills. This study aimed to clarify the characteristics of and risk factors for IRs in Tra + Per combination therapy. METHODS: Between March 2013 and December 2019, 64 patients with breast cancer who started Tra + Per combination therapy were included in the study. The severity of IRs was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. RESULTS: The incidence of IRs in the Tra + Per combination therapy was 48.4% (31/64). The severity of IRs in the Tra + Per combination therapy was Grade 1 (9 patients) and Grade 2 (22 patients). Lymphocyte counts were significantly different between the IR and non-IR groups in patients receiving Tra + Per combination therapy (univariate analysis, p = 0.006; multivariate analysis, p = 0.050). ROC curve analysis found the cutoff value of lymphocyte counts were 1.60 (× 103/µL). The incidence of IRs in the lymphocyte counts ≥ 1.60 group was significantly higher than that in the lymphocyte counts < 1.60 group (p < 0.001). CONCLUSION: Our study indicates that the severity of IRs in most patients is moderate or less and the risk of IRs is higher in patients with higher lymphocyte counts (≥ 1.60 × 103/µL).

Copper-Catalyzed Asymmetric Sulfonylative Desymmetrization of Glycerol.

Glycerol is the main side product in the biodiesel manufacturing process, and the development of glycerol valorization methods would indirectly contribute the sustainable biodiesel production and decarbonization. Transformation of glycerol to optically active C3 units would be one of the attractive routes for glycerol valorization. We herein present the asymmetric sulfonylative desymmetrization of glycerol by using a CuCN/(R,R)-PhBOX catalyst system to provide an optically active monosulfonylated glycerol in high efficiency. A high degree of enantioselectivity was achieved with a commercially available chiral ligand and an inexpensive carbonate base. The optically active monosulfonylated glycerol was successfully transformed into a C3 unit attached with differentially protected three hydroxy moieties. In addition, the synthetic utility of the present reaction was also demonstrated by the transformation of the monosulfonylated glycerol into an optically active synthetic ceramide, sphingolipid E.

Oxidation of an Internal-Edge-Substituted [5]Helicene-Derived Phosphine Synchronously Enhances Circularly Polarized Luminescence.

Invited for the cover of this issue are the groups of Kazuteru Usui and Satoru Karasawa at Showa Pharmaceutical University, and Yoshitane Imai at Kindai University. The image depicts how a phosphine-oxide-bearing helicene exhibits markedly enhanced CPL response in the excited state compared with that of one with a corresponding phosphine. Read the full text of the article at 10.1002/chem.202202922.

Oxidation of an Internal-Edge-Substituted [5]Helicene-Derived Phosphine Synchronously Enhances Circularly Polarized Luminescence.

Small chiral organic molecules with CD properties are in high demanded due to their potential use in promising electronic and biological applications. Herein, we reveal a system in which the oxidation of a phosphino group to the corresponding phosphine oxide on the inner rim of a helicene derivative induces a CPL response. Laterally π-extended 7,8-dihydro[5]helicenes bearing phosphine and phosphine oxide groups on their inner helical rims (i. e., the C1 position) were synthesized, and their helical structures were unambiguously determined by X-ray crystallography. The photophysical (UV/visible and emission) and chiroptical properties of these compounds were investigated in various solvents. Despite their structural similarities, phosphine oxide showed a significantly better CPL response than phosphine, with a high dissymmetry factor for emission (|glum |=(1.3-1.9)×10-3 ) that can be attributed to structural changes in the interior of the helicene helix.

Electrochemical formal homocoupling of sec-alcohols.

Electrochemical pinacol coupling of carbonyl compounds in an undivided cell with a sacrificial anode would be a promising approach toward synthetically valuable vic-1,2-diol scaffolds without using low-valent metal reductants. However, sacrificial anodes produce an equimolar amount of metal waste, which may be a major issue in terms of sustainable chemistry. Herein, we report a sacrificial anode-free electrochemical protocol for the synthesis of pinacol-type vic-1,2-diols from sec-alcohols, namely benzyl alcohol derivatives and ethyl lactate. The corresponding vic-1,2-diols are obtained in moderate to good yields, and good to high levels of stereoselectivity are observed for sec-benzyl alcohol derivatives. The present transformations smoothly proceed in a simple undivided cell under constant current conditions without the use of external chemical oxidants/reductants, and transition-metal catalysts.

A simplified analog of debromoaplysiatoxin lacking the B-ring of spiroketal moiety retains protein kinase C-binding and antiproliferative activities.

A simplified analog (3) of aplysiatoxin was synthesized. Compound 3 has only one tetrahydropyran ring at positions 3-7, the A-ring of the spiroketal moiety, which is the conformation-controlling unit for the macrolactone ring. Nuclear magnetic resonance (NMR) analysis and density functional theory (DFT) calculations indicated that 3 existed as an equilibrium mixture of two conformers arising from inversion of the chair conformation of the 2,6-trans-tetrahydropyran ring. The des-B-ring analog 3 binds protein kinase C isozymes and exhibits antiproliferative activity toward human cancer cell lines, comparable to 18-deoxy-aplog-1 with a spiroketal moiety.

Diversity of endophytic bacterial microbiota in grapevine shoot xylems varies depending on wine grape-growing region, cultivar, and shoot growth stage.

Next-generation sequencing technology may clarify microbiota that are as yet poorly understood in the soil, the rhizosphere, and the phyllosphere of vineyards. To provide new information on the interaction between grapevine and microorganisms, we focused on the endophytic microbiota in grapevine. We performed endophytic microbiome analysis of the shoot xylems of four cultivars, Vitis vinifera cvs. Chardonnay, Pinot Noir, Cabernet Sauvignon, and Vitis sp. cv. Koshu, grown in eleven vineyards in Japan. The number of endophytic fungal species was small in the grapevine shoot xylems and could not be analyzed further, whereas a total of 7,019,600 amplicon sequences (46,642-285,003 per shoot xylem) and 1305 bacterial operational taxonomic units were obtained by analysis of the V3-V4 region of the bacterial 16S rRNA gene. Gammaproteobacteria was predominant in the shoot xylems at the shoot elongation stage irrespective of the cultivar, whereas Alphaproteobacteria and Oxyphotobacteria were predominant at véraison. Actinobacteria, Bacteroidia, Bacilli, and Clostridia were also detected in the shoot xylems. The endophytic bacterial microbiota in Koshu and Pinot Noir shoot xylems were similar irrespective of the grapevine-growing region. In contrast, the endophytic bacterial microbiota in Chardonnay and Cabernet Sauvignon showed diversity and complexity among grapevine-growing regions. Alpha diversity analysis revealed that Koshu shoot xylems had a higher diversity of endophytic bacterial microbiota than Pinot Noir, Chardonnay, and Cabernet Sauvignon shoot xylems, and that grapevine shoot xylems at the shoot elongation stage had a higher diversity of endophytic bacterial microbiota than those at véraison. Principal coordinate analysis (PCoA) demonstrated that the profiles of the endophytic bacterial microbiota in grapevine shoot xylems at véraison were relatively uniform compared with those at the shoot elongation stage. Multidimensional scaling analysis showed that the plots of all cultivars were generally apart from each other at the shoot elongation stage and then became close to each other at véraison. The plots of all grapevine-growing regions cultivating Koshu were close to each other, whereas those of grapevine-growing regions cultivating Chardonnay and Cabernet Sauvignon were apart from each other. The findings of this study suggest that the endophytic bacterial microbiota in grapevine shoot xylems varied depending on the cultivar and the grapevine-growing region even for the same cultivars, and that the microbiota fluctuated depending on the shoot growth stage.

Organocatalytic Synthesis of Phenols from Diaryliodonium Salts with Water under Metal-Free Conditions.

The metal-free synthesis of phenols from diaryliodonium salts with water was developed by using N-benzylpyridin-2-one as an organocatalyst. In this process, sterically congested, functionalized, and heterocycle-containing iodonium salts were smoothly converted to the desired products, and the clofibrate and mecloqualone derivatives were also synthesized in high yields. In addition, the gram-scale experiment was successfully carried out with 10 mmol of a sterically congested substrate.

Bacterial Community of Water Yam (Dioscorea alata L.) cv. A-19.

The bacterial community of water yam (Dioscorea alata L.) cv. A-19 is vital because it may promote plant growth without the need for fertilization. However, the influence of fertilization practices on the composition and proportion of the bacterial community of water yam cv. A-19 has not yet been extensively examined. Therefore, we herein investigated the diversity and composition of the bacterial community of water yam cv. A-19 cultivated with and without chemical fertilization using amplicon community profiling based on 16S rRNA gene sequences. No significant difference was detected in the growth of plants cultivated with or without chemical fertilization. Alpha diversity indices were significantly dependent on each compartment, and a decrease was observed in indices from the belowground (rhizosphere and root) to aboveground compartments (stem and leaf). The bacterial composition of each compartment was clustered into three groups: bulk soil, rhizosphere and root, and stem and leaf. Chemical fertilization did not significantly influence the diversity or composition of the water yam cv. A-19 bacterial community. It remained robust in plants cultivated with chemical fertilization. The amplicon community profiling of bacterial communities also revealed the dominance of two bacterial clades, the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade and Burkholderia-Caballeronia-Paraburkholderia clade, with and without chemical fertilization. This is the first study to characterize the bacterial community of water yam cv. A-19 cultivated with and without chemical fertilization.

Long-term follow-up of a patient with autosomal dominant lower extremity-predominant spinal muscular atrophy-2 due to a BICD2 variant.

INTRODUCTION: Bicaudal D homolog 2 (BICD2) is a causative gene of autosomal-dominant lower extremity-predominant spinal muscular atrophy-2 (SMA-LED2). The severity of SMA-LED2 varies widely, ranging from cases in which patients are able to walk to cases in which severe joint contractures lead to respiratory failure. In this study, we report the long-term course of a case of SMA-LED2 in comparison with previous reports. CASE REPORT: The patient was a 19-year-old woman. She had knee and hip dislocations with contractures, femoral fracture, and talipes calcaneovalgus since birth, and was diagnosed with arthrogryposis multiplex congenita. Intense respiratory support was not needed during the neonatal period. She had aspiration pneumonia repeatedly, necessitating NICU admission until 8 months of age. She achieved head control at 9 months of age and was able to sit at 2 years of age; however, she could not walk. Tube feeding was required until 3 years of age. At present, she can eat orally, move around with a wheelchair, and write words by herself. She needs non-invasive positive pressure ventilation during sleep because of a restrictive respiratory disorder during adolescence. Exome analysis identified a de novo heterozygous missense variant (c.2320G>A; p.Glu774Lys) in BICD2. CONCLUSION: Patients with SMA-LED2 may have a relatively better prognosis in terms of social activities in comparison with the dysfunction in the neonatal period. Moreover, it is important to periodically evaluate respiratory function in patients with SMA-LED2 because respiratory dysfunction may occur during adolescence.