The impact of CDCA5 expression on the immune microenvironment and its potential utility as a biomarker for PD-L1/PD-1 inhibitors in lung adenocarcinoma.

BACKGROUND: Studies have highlighted the important role of cell division cycle associated 5 (CDCA5) in tumor-associated immune dysfunction. We studied immune dysfunction based on CDCA5 expression in lung adenocarcinoma and investigated its potential as a biomarker for patients undergoing anti-programmed death protein-1/ programmed death ligand-1 (PD-1/PD-L1) inhibitor therapy. METHODS: We used the CIBERSORTx algorithm to investigate the immune cell distribution based on CDCA5 and explored its potential as a biomarker for PD-1/PD-L1 therapy using Tumor Immune Dysfunction and Exclusion in three lung adenocarcinoma datasets. Thus, we validated the role of CDCA5 as a biomarker in patients treated with PD-1/PD-L1 inhibitors. We also investigated the pathways through which CDCA5 regulates PD-L1 expression in a cell line. RESULTS: The high CDCA5 expression group showed elevated interferon gamma signature, CD274 expression, CD8+ T cell levels, tumor mutation burden, and microsatellite instability. Higher CDCA5 expression was associated with poorer prognosis in patients not treated with PD-1/PD-L1 inhibitors. However, in patients treated with PD-1/PD-L1 inhibitors, higher CDCA5 expression correlated with better response rates and prognosis. CDCA5 expression positively correlated with inhibitory immune checkpoint molecules. CDCA5 regulated the expression of PD-L1 through the ANXA/AKT pathway, and combined suppression of CDCA5 and PD-L1 synergistically inhibited cell proliferation. CONCLUSIONS: CDCA5 served as a promising biomarker for patients undergoing PD-L1/PD-1 inhibitor treatment, and co-inhibition of CDCA5 and PD-L1 could serve as an effective therapeutic strategy.

The Application of Fluorescence In Situ Hybridization in the Prescreening of Veronica Hybrids.

Fluorescence in situ hybridization (FISH), a molecular cytogenetic technique that enables the visualization and identification of specific DNA sequences within chromosomes, has emerged as a pivotal tool in plant breeding programs, particularly in the case of Veronica species. Veronica, a genus with a complex reproductive system, often poses challenges in accurately identifying hybrids because of its tendency to hybridize, which leads to intricate genetic variation. This study focused on the use of FISH as a prescreening method to identify true hybrids in Veronica breeding programs. FISH analysis was first performed on the parents to identify their 45S and 5S rDNA signals, along with their respective chromosome numbers. The signals were then compared with those of the twenty progenies with reference to their supposed parents. Five true hybrids, seven self-pollinated progenies, and eight false hybrids were identified through FISH. The findings highlight the significance of FISH as a screening method that contributes significantly to the efficiency of Veronica breeding programs by ensuring the preservation of desired genetic traits and minimizing the inadvertent inclusion of misidentified hybrids. To conclude, this study underscores the vital role of FISH in enhancing the precision and success of breeding programs and opens new avenues for improved breeding strategies and crop development.

Characteristics of the immune microenvironment associated with RRM2 expression and its application to PD-L1/PD-1 inhibitors in lung adenocarcinoma.

Recent studies have indicated that RRM2 plays a crucial part in the tumor immune microenvironment. According to the expression of RRM2, we evaluated immune cell infiltration, immunotherapy biomarkers, and the expression of immune checkpoint molecules in four lung adenocarcinoma (LUAD) datasets. We employed the Tumor Immune Dysfunction and Exclusion (TIDE) and CIBERSORTx algorithms to examine the patterns of immune cell distribution and evaluate the responses to anti-programmed death protein-1/programmed death ligand-1 (PD-1/PD-L1) therapy in three publicly available LUAD datasets. These findings were corroborated using a validation group comprising patients who received treatment with PD-1/PD-L1 inhibitors. Additionally, we conducted experiments using LUAD cell lines to investigate how RRM2 affects the expression of PD-L1. In comparison to the low RRM2 group, the high RRM2 group exhibited a high interferon gamma signature, high T-cell-inflamed signature, high CD274 expression, high CD8+ T cell levels, low cancer-associated fibroblasts, and low M2 macrophages, according to TIDE analysis in the three LUAD datasets. Analysis of the three LUAD datasets using CIBERSORTx confirmed a positive correlation between RRM2 and CD8+ T cells, and this finding was validated by immunohistochemistry in a separate validation set. In the three LUAD datasets without PD-1/PD-L1 inhibitor treatment, higher RRM2 expression was associated with a poorer prognosis. However, in the LUAD dataset treated with PD-1/PD-L1 inhibitors, higher RRM2 expression was associated with better prognosis. In the three datasets, the high-RRM2 group exhibited higher expression of inhibitory immune checkpoint molecules. In a LUAD cell line study, we discovered that RRM2 regulates PD-L1 expression through the ANXA1/AKT pathway. The expression of RRM2 shows promise as a predictive biomarker for PD-1/PD-L1 inhibitors in LUAD patients, and it may represent a new target to overcome resistance to PD-L1/PD-1 therapies.

Cytogenetic Study and Pollen Viability of Phalaenopsis Queen Beer 'Mantefon'.

Intergeneric and interspecific hybridization has been employed for the breeding of Phalaenopsis to transfer desirable traits between species, producing novel phenotypes with improved size, color, form, and flower-bearing ability. These characteristics are often enhanced; however, many of these hybrids are triploids and have reduced or complete sterility, for example, Phalaenopsis Queen Beer 'Mantefon', an important novelty-type cultivar in Asia, particularly in China, Japan, and Republic of Korea. Despite the increasing demand for the crop for ornamental purposes, little is known about its cytogenetics, which is essential for breeding and, consequently, crop improvement. In this study, karyotyping using fluorescence in situ hybridization, meiotic chromosome behavior analysis, pollen staining, and in vitro viability germination tests were performed to understand the cause of hybrid sterility and pollen abnormality in Phalaenopsis Queen Beer 'Mantefon' from a cytogenetic perspective. Viability tests revealed pollen infertility at all flower developmental stages, confirmed by the absence of pollen tube growth. Aberrant chromosomal behavior was observed in pollen mother cells (PMCs), frequently forming univalents, chromosomal bridges, and laggards during the entire meiotic process. PMCs were also divided irregularly into sporads with varying numbers of micronuclei, which may be responsible for pollen sterility in this cultivar. Altogether, the cytogenetic analyses provided insights into the pollen development of Phalaenopsis Queen Beer 'Mantefon' and the conceivable causes of its infertility.

CD38 Inhibition Protects Fructose-Induced Toxicity in Primary Hepatocytes.

A fructose-enriched diet is thought to contribute to hepatic injury in developing non-alcoholic steatohepatitis (NASH). However, the cellular mechanism of fructose-induced hepatic damage remains poorly understood. This study aimed to determine whether fructose induces cell death in primary hepatocytes, and if so, to establish the underlying cellular mechanisms. Our results revealed that treatment with high fructose concentrations for 48 h induced mitochondria-mediated apoptotic death in mouse primary hepatocytes (MPHs). Endoplasmic reticulum stress responses were involved in fructose-induced death as the levels of phosho-eIF2α, phospho-C-Jun-N-terminal kinase (JNK), and C/EBP homologous protein (CHOP) increased, and a chemical chaperone tauroursodeoxycholic acid (TUDCA) prevented cell death. The impaired oxidation metabolism of fatty acids was also possibly involved in the fructose-induced toxicity as treatment with an AMP-activated kinase (AMPK) activator and a PPAR-α agonist significantly protected against fructose-induced death, while carnitine palmitoyl transferase I inhibitor exacerbated the toxicity. However, uric acid-mediated toxicity was not involved in fructose-induced death as uric acid was not toxic to MPHs, and the inhibition of xanthine oxidase (a key enzyme in uric acid synthesis) did not affect cell death. On the other hand, treatment with inhibitors of the nicotinamide adenine dinucleotide (NAD)+-consuming enzyme CD38 or CD38 gene knockdown significantly protected against fructose-induced toxicity in MPHs, and fructose treatment increased CD38 levels. These data suggest that CD38 upregulation plays a role in hepatic injury in the fructose-enriched diet-mediated NASH. Thus, CD38 inhibition may be a promising therapeutic strategy to prevent fructose-enriched diet-mediated NASH.

Retention of Mutations in Colchicine-Induced Ornamental Succulent Echeveria 'Peerless'.

Mutation breeding has produced promising results, with exceptional attributes including pest/disease and environmental tolerance and desirable ornamental traits. Among the tools used in mutation breeding, chemical mutation is the most inexpensive way to develop novel plants. Succulents have gained popularity with high market demand because they require minimal watering and have plastic-like visuals. Ornamental succulents with rare leaf morphologies are costly. An LD50 study was conducted beforehand to determine the survival rates of colchicine-treated Echeveria 'Peerless'. Mutants in the first generation (MV1) were identified and analyzed. Determining whether mutagenic characteristics are carried to the subsequent generation (MV2) is a key component in breeding programs. Additional investigation was performed by producing MV2 plants through vegetative propagation to determine mutagenic retention. For MV2, mutants exhibited shortened leaves, increased leaf width and thickness, and fewer leaves, which significantly differed from the control, indicating compactness, wider leaf apex, and varying leaf color. To confirm the mutations, stomatal analysis was conducted, wherein there was a decrease in density and an increase in stomatal size. Likewise, chromosome counting and flow cytometry analysis confirmed the induction of polyploidization. Colchicine induction to develop new cultivars with novel phenotypic and cytogenetic characters is suitable for ornamental succulents.

Mitochondrial protease ClpP supplementation ameliorates diet-induced NASH in mice.

BACKGROUND & AIMS: Mitochondrial dysfunction is considered a pathogenic linker in the development of non-alcoholic steatohepatitis (NASH). Inappropriate mitochondrial protein-quality control, possibly induced by insufficiency of the mitochondrial matrix caseinolytic protease P (ClpP), can potentially cause mitochondrial dysfunction. Herein, we aimed to investigate hepatic ClpP levels in a diet-induced model of NASH and determine whether supplementation of ClpP can ameliorate diet-induced NASH. METHODS: NASH was induced by a high-fat/high-fructose (HF/HFr) diet in C57BL/6J mice. Stress/inflammatory signals were induced in mouse primary hepatocytes (MPHs) by treatment with palmitate/oleate (PA/OA). ClpP levels in hepatocytes were reduced using the RNAi-mediated gene knockdown technique but increased through the viral transduction of ClpP. ClpP activation was induced by administering a chemical activator of ClpP. RESULTS: Hepatic ClpP protein levels in C57BL/6J mice fed a HF/HFr diet were lower than the levels in those fed a normal chow diet. PA/OA treatment also decreased the ClpP protein levels in MPHs. Overexpression or activation of ClpP reversed PA/OA-induced mitochondrial dysfunction and stress/inflammatory signal activation in MPHs, whereas ClpP knockdown induced mitochondrial dysfunction and stress/inflammatory signals in these cells. On the other hand, ClpP overexpression or activation improved HF/HFr-induced NASH characteristics such as hepatic steatosis, inflammation, fibrosis, and injury in the C57BL/6J mice, whereas ClpP knockdown further augmented steatohepatitis in mice fed a HF/HFr diet. CONCLUSIONS: Reduced ClpP expression and subsequent mitochondrial dysfunction are key to the development of diet-induced NASH. ClpP supplementation through viral transduction or chemical activation represents a potential therapeutic strategy to prevent diet-induced NASH. LAY SUMMARY: Western diets, containing high fat and high fructose, often induce non-alcoholic steatohepatitis (NASH). Mitochondrial dysfunction is considered pathogenically linked to diet-induced NASH. We observed that the mitochondrial protease ClpP decreased in the livers of mice fed a western diet and supplementation of ClpP ameliorated western diet-induced NASH.

Cytogenetic analysis of Bienertia sinuspersici Akhani as the first step in genome sequencing.

BACKGROUND: C4 plants are efficient in suppressing photorespiration and enhancing carbon gain as compared to C3 plants. Bienertia sinuspersici Akhani is one of the few species in the family Amaranthaceae that can perform C4 photosynthesis within individual chlorenchyma cells, without the conventional Kranz anatomy in its leaf. This plant is salt-tolerant and is well-adapted to thrive in hot and humid climates. To date, there have been no reported cytogenetic analyses yet on this species. OBJECTIVE: This study aims to provide a cytogenetic analysis of B. sinuspersici as the first step in genome sequencing. METHODS: Fluorescence in situ hybridization (FISH) karyotype analysis was conducted using the metaphase chromosomes of B. sinuspersici probed with 5S and 45S rDNA and Arabidopsis-type telomeric repeats. RESULTS: Results of the cytogenetic analysis confirmed that B. sinuspersici has 2n = 2x = 18 consisting of nine pairs of metacentric chromosomes. Two loci of 45S rDNA were found on the distal regions of the short arm of chromosome 7. Nine loci of 5S rDNA were found in the pericentromeric regions of chromosomes 1, 3, 4, 6, and 8, which also colocalized with Arabidopsis-type telomeric repeats; while four loci in the interstitial regions of chromosome 5 and 8 can be observed. The single locus of 5S rDNA that was found in chromosome 8 appears to be hemizygous. CONCLUSION: The FISH karyotype analysis, based on the combination of rDNAs, telomeric tandem repeat markers and C0t DNA chromosome landmarks, allowed efficient chromosome identification and provided useful information in characterizing the genome of B. sinuspersici.

Sodium fluorocitrate having inhibitory effect on fatty acid uptake ameliorates high fat diet-induced non-alcoholic fatty liver disease in C57BL/6J mice.

Non-alcoholic fatty liver disease (NAFLD) is excessive fat build-up in the liver without alcohol consumption and includes hepatic inflammation and damage. Excessive influx of fatty acids to liver from circulation is thought to be a pathogenic cause for the development of NAFLD. Thus, inhibition of fatty acid intake into hepatocyte would be a maneuver for protection from high fat diet (HFD)-induced NAFLD. This study was initiated to determine whether sodium fluorocitrate (SFC) as a fatty acid uptake inhibitor could prevent palmitate-induced lipotoxicity in hepatocytes and protect the mice from HFD-induced NAFLD. SFC significantly inhibited the cellular uptake of palmitate in HepG2 hepatocytes, and thus prevented palmitate-induced fat accumulation and death in these cells. Single treatment with SFC reduced fasting-induced hepatic steatosis in C57BL/6J mice. Concurrent treatment with SFC for 15 weeks in HFD-fed C57BL/6J mice prevented HFD-induced fat accumulation and stress/inflammatory signal activation in the liver. SFC restored HFD-induced increased levels of serum alanine aminotransferase and aspartate aminotransferases as hepatic injury markers in these mice. SFC treatment also improved HFD-induced hepatic insulin resistance, and thus ameliorated HFD-induced hyperglycemia. In conclusion, inhibition of fatty acid mobilization into liver through SFC treatment can be a strategy to protect from HFD-induced NAFLD.

Sodium fluorocitrate having protective effect on palmitate-induced beta cell death improves hyperglycemia in diabetic db/db mice.

Beta cell loss and insulin resistance play roles in the pathogenesis of type 2 diabetes. Elevated levels of free fatty acids in plasma might contribute to the loss of beta cells. The objective of this study was to find a chemical that could protect against palmitate-induced beta cell death and investigate whether such chemical could improve hyperglycemia in mouse model of type 2 diabetes. Sodium fluorocitrate (SFC), an aconitase inhibitor, was found to be strongly and specifically protective against palmitate-induced INS-1 beta cell death. However, the protective effect of SFC on palmitate-induced cell death was not likely to be due to its inhibitory activity for aconitase since inhibition or knockdown of aconitase failed to protect against palmitate-induced cell death. Since SFC inhibited the uptake of palmitate into INS-1 cells, reduced metabolism of fatty acids was thought to be involved in SFC's protective effect. Ten weeks of treatment with SFC in db/db diabetic mice reduced glucose level but remarkably increased insulin level in the plasma. SFC improved impairment of glucose-stimulated insulin release and also reduced the loss of beta cells in db/db mice. Conclusively, SFC possessed protective effect against palmitate-induced lipotoxicity and improved hyperglycemia in mouse model of type 2 diabetes.

The complete chloroplast genome of Lilium distichum Nakai (Liliaceae).

Lilium distichum is a native lily species in Korea, northeastern China and far eastern Russia. The complete chloroplast genome sequence of L. distichum was generated by de novo assembly using whole genome next generation sequences. The chloroplast genome of L. distichum was 152 598 bp in length and divided into four distinct regions, such as large single copy region (82 031 bp), small single copy region (17 487 bp) and a pair of inverted repeat regions (26 540 bp). The genome annotation predicted a total of 112 genes, including 78 protein-coding genes, 30 tRNA genes,and 4 rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that L. distichum is most closely related to L. superbum (Turk's-cap lily).

Elucidating the triplicated ancestral genome structure of radish based on chromosome-level comparison with the Brassica genomes.

KEYMESSAGE: This study presents a chromosome-scale draft genome sequence of radish that is assembled into nine chromosomal pseudomolecules. A comprehensive comparative genome analysis with the Brassica genomes provides genomic evidences on the evolution of the mesohexaploid radish genome. Radish (Raphanus sativus L.) is an agronomically important root vegetable crop and its origin and phylogenetic position in the tribe Brassiceae is controversial. Here we present a comprehensive analysis of the radish genome based on the chromosome sequences of R. sativus cv. WK10039. The radish genome was sequenced and assembled into 426.2 Mb spanning >98 % of the gene space, of which 344.0 Mb were integrated into nine chromosome pseudomolecules. Approximately 36 % of the genome was repetitive sequences and 46,514 protein-coding genes were predicted and annotated. Comparative mapping of the tPCK-like ancestral genome revealed that the radish genome has intermediate characteristics between the Brassica A/C and B genomes in the triplicated segments, suggesting an internal origin from the genus Brassica. The evolutionary characteristics shared between radish and other Brassica species provided genomic evidences that the current form of nine chromosomes in radish was rearranged from the chromosomes of hexaploid progenitor. Overall, this study provides a chromosome-scale draft genome sequence of radish as well as novel insight into evolution of the mesohexaploid genomes in the tribe Brassiceae.

The complete chloroplast genome sequence of Lilium hansonii Leichtlin ex D.D.T.Moore.

Lilium hansonii is a lily species native to Korea and an important wild species for lily breeding. The chloroplast genome of L. hansonii was completed by de novo assembly using the small amount of whole genome sequencing data. The chloroplast genome of L. hansonii was 152 655 bp long and consisted of large single copy region (82 051 bp), small single copy region (17 620 bp) and a pair of inverted repeat regions (26 492 bp). A total of 115 genes were annotated, which included 81 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that L. hansonii is most closely related to L. superbum (Turk's-cap lily) and L. longiflorum (Easter lily).

The complete chloroplast genomes of Lilium tsingtauense Gilg (Liliaceae).

Lilium tsingtauense, known as 'Korean wheel lily' and 'Twilight lily', is a lily species naturally distributed in Korea. The complete chloroplast genome sequences of L. tsingtauense was obtained by de novo assembly using whole-genome next-generation sequencing data. The chloroplast genome of L. tsingtauense was 152,710 bp in length and consisted of four distinct regions, such as large single-copy region (82,059 bp), small single-copy region (17,619 bp) and a pair of inverted repeat regions (26,516 bp). The genome contained a total of 113 genes, including 79 protein-coding genes, 30 tRNA genes and 4 rRNA genes. Phylogenetic analysis with the reported chloroplast genomes revealed that L. tsingtauense is most closely related to Lilium hansonii, a lily species native to Korea.

FISH and GISH: molecular cytogenetic tools and their applications in ornamental plants.

KEY MESSAGE: The innovations in chromosome engineering have improved the efficiency of interrogation breeding, and the identification and transfer of resistance genes from alien to native species. Recent advances in molecular biology and cytogenetics have brought revolutionary, conceptual developments in mitosis and meiosis research, chromosome structure and manipulation, gene expression and regulation, and gene silencing. Cytogenetic studies offer integrative tools for imaging, genetics, epigenetics, and cytological information that can be employed to enhance chromosome and molecular genomic research in plant taxa. In situ hybridization techniques, such as fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH), can identify chromosome morphologies and sequences, amount and distribution of various types of chromatin in chromosomes, and genome organization during the metaphase stage of meiosis. Over the past few decades, various new molecular cytogenetic applications have been developed. The FISH and GISH techniques present an authentic model for analyzing the individual chromosome, chromosomal segments, or the genomes of natural and artificial hybrid plants. These have become the most reliable techniques for studying allopolyploids, because most cultivated plants have been developed through hybridization or polyploidization. Moreover, introgression of the genes and chromatin from the wild types into cultivated species can also be analyzed. Since hybrid derivatives may have variable alien chromosome numbers or chromosome arms, the use of these approaches opens new avenues for accurately identifying genome differences.

Construction of a reference genetic map of Raphanus sativus based on genotyping by whole-genome resequencing.

KEY MESSAGE: This manuscript provides a genetic map of Raphanus sativus that has been used as a reference genetic map for an ongoing genome sequencing project. The map was constructed based on genotyping by whole-genome resequencing of mapping parents and F 2 population. Raphanus sativus is an annual vegetable crop species of the Brassicaceae family and is one of the key plants in the seed industry, especially in East Asia. Assessment of the R. sativus genome provides fundamental resources for crop improvement as well as the study of crop genome structure and evolution. With the goal of anchoring genome sequence assemblies of R. sativus cv. WK10039 whose genome has been sequenced onto the chromosomes, we developed a reference genetic map based on genotyping of two parents (maternal WK10039 and paternal WK10024) and 93 individuals of the F2 mapping population by whole-genome resequencing. To develop high-confidence genetic markers, ~83 Gb of parental lines and ~591 Gb of mapping population data were generated as Illumina 100 bp paired-end reads. High stringent sequence analysis of the reads mapped to the 344 Mb of genome sequence scaffolds identified a total of 16,282 SNPs and 150 PCR-based markers. Using a subset of the markers, a high-density genetic map was constructed from the analysis of 2,637 markers spanning 1,538 cM with 1,000 unique framework loci. The genetic markers integrated 295 Mb of genome sequences to the cytogenetically defined chromosome arms. Comparative analysis of the chromosome-anchored sequences with Arabidopsis thaliana and Brassica rapa revealed that the R. sativus genome has evident triplicated sub-genome blocks and the structure of gene space is highly similar to that of B. rapa. The genetic map developed in this study will serve as fundamental genomic resources for the study of R. sativus.

Solvent-free synthesis of Cu2ZnSnS4 nanocrystals: a facile, green, up-scalable route for low cost photovoltaic cells.

Efficient Cu2ZnSnSe4 (CZTSe) solar cells were fabricated with a simple, environmentally friendly, and scalable synthetic method for Cu2ZnSnS4 (CZTS) nanocrystals. CZTS nanoparticles were mechanochemically synthesized from elemental precursors on a relatively large scale (∼20 g), during which no solvents or additives were used, thus alleviating the complex process of particle synthesis. An analysis of the time evolution of the crystalline phase and morphology of precursor powders revealed that the formation of the CZTS compound was completed in 0.5 h once initiated, suggesting that the mechanochemically induced self-propagating reaction prevails. CZTS ink was prepared by dispersing the as-synthesized nanoparticles in an environmentally benign solvent (160 mg mL(-1) in ethanol) without using any additives, after which it was cast onto Mo-coated glass substrates by a doctor-blade method. Subsequent reactive annealing at 560 °C under a Se-containing atmosphere resulted in substantial grain growth along with the nearly complete substitution of Se. The CZTSe solar cells therefrom exhibited power conversion efficiency levels as high as 6.1% (based on the active area, 0.44 cm(2)) with a relatively high open-circuit voltage (0.42 V) in comparison with the bandgap energy of 1.0 eV.

Exploitation of induced 2n-gametes for plant breeding.

Unreduced gamete formation derived via abnormal meiotic cell division is an important approach to polyploidy breeding. This process is considered the main driving force in spontaneous polyploids formation in nature, but the potential application of these gametes to plant breeding has not been fully exploited. An effective mechanism for their artificial induction is needed to attain greater genetic variation and enable efficient use of unreduced gametes in breeding programs. Different approaches have been employed for 2n-pollen production including interspecific hybridization, manipulation of environmental factors and treatment with nitrous oxide, trifluralin, colchicine, oryzalin and other chemicals. These chemicals can act as a stimulus to produce viable 2n pollen; however, their exact mode of action, optimum concentration and developmental stages are still not known. Identification of efficient methods of inducing 2n-gamete formation will help increase pollen germination of sterile interspecific hybrids for inter-genomic recombination and introgression breeding to develop new polyploid cultivars and increase heterozygosity among plant populations. Additionally, the application of genomic tools and identification and isolation of genes and mechanisms involved in the induction of 2n-gamete will enable increased exploitation in different plant species, which will open new avenues for plant breeding.

Supplementation of pyruvate prevents palmitate-induced impairment of glucose uptake in C2 myotubes.

Elevated fatty acid levels have been thought to contribute to insulin resistance. Repression of the glucose transporter 4 (GLUT4) gene as well as impaired GLUT4 translocation may be a mediator for fatty acid-induced insulin resistance. This study was initiated to determine whether palmitate treatment repressed GLUT4 expression, whether glucose/fatty acid metabolism influenced palmitate-induced GLUT4 gene repression (PIGR), and whether attempts to prevent PIGR restored palmitate-induced impairment of glucose uptake (PIIGU) in C2 myotubes. Not only stimulators of fatty acid oxidation, such as bezafibrate, AICAR, and TOFA, but also TCA cycle substrates, such as pyruvate, leucine/glutamine, and α-ketoisocaproate/monomethyl succinate, significantly prevented PIGR. In particular, supplementing with pyruvate through methyl pyruvate resulted in nearly complete prevention of PIIGU, whereas palmitate treatment reduced the intracellular pyruvate level. These results suggest that pyruvate depletion plays a critical role in PIGR and PIIGU; thus, pyruvate supplementation may help prevent obesity-induced insulin resistance in muscle cells.