Expression Levels Of Multiple Genes Research Articles

Identification of ClpB, a molecular chaperone involved in the stress tolerance and virulence of Streptococcus agalactiae

Bacterial ClpB is an ATP-dependent disaggregate that belongs to the Hsp100/Clp family and facilitates bacterial survival under hostile environmental conditions. Streptococcus agalactiae, which is regarded as the major bacterial pathogen of farmed Nile tilapia (Oreochromis niloticus), is known to cause high mortality and large economic losses. Here, we report a ClpB homologue of S. agalactiae and explore its functionality. S. agalactiae with a clpB deletion mutant (∆clpB) exhibited defective tolerance against heat and acidic stress, without affecting growth or morphology under optimal conditions. Moreover, the ΔclpB mutant exhibited reduced intracellular survival in RAW264.7 cells, diminished adherence to the brain cells of tilapia, increased sensitivity to leukocytes from the head kidney of tilapia and whole blood killing, and reduced mortality and bacterial loads in a tilapia infection assay. Furthermore, the reduced virulence of the ∆clpB mutant was investigated by transcriptome analysis, which revealed that deletion of clpB altered the expression levels of multiple genes that contribute to the stress response as well as certain metabolic pathways. Collectively, our findings demonstrated that ClpB, a molecular chaperone, plays critical roles in heat and acid stress resistance and virulence in S. agalactiae. This finding provides an enhanced understanding of the functionality of this ClpB homologue in gram-positive bacteria and the survival strategy of S. agalactiae against immune clearance during infection.

The Exon Junction Complex Factor RBM8A in Glial Fibrillary Acid Protein-Expressing Astrocytes Modulates Locomotion Behaviors.

The role of RNA Binding Motif Protein 8a (RBM8A), an exon junction complex (EJC) component, in neurodevelopmental disorders has been increasingly studied for its crucial role in regulating multiple levels of gene expression. It regulates mRNA splicing, translation, and mRNA degradation and influences embryonic development. RBM8A protein is expressed in both neurons and astrocytes, but little is known about RBM8A's specific role in glial fibrillary acid protein (GFAP)-positive astrocytes. To address the role of RBM8A in astrocytes, we generated a conditional heterozygous knockout (KO) mouse line of Rbm8a in astrocytes using a GFAP-cre line. We confirmed a decreased expression of RBM8A in astrocytes of heterozygous conditional KO mice via RT-PCR and Sanger sequencing, as well as qRT-PCR, immunohistochemistry, and Western blot. Interestingly, these mice exhibit significantly increased movement and mobility, alongside sex-specific altered anxiety in the open field test (OFT) and elevated plus maze (OPM) tests. These tests, along with the rotarod test, suggest that these mice have normal motor coordination but hyperactive phenotypes. In addition, the haploinsufficiency of Rbm8a in astrocytes leads to a sex-specific change in astrocyte density in the dentate gyrus. This study further reveals the contribution of Rbm8a deletion to CNS pathology, generating more insights via the glial lens of an Rbm8a model of neurodevelopmental disorder.

Citral enhances disease resistance in postharvest citrus fruit through inducing jasmonic acid pathway and accumulating phenylpropanoid compounds

Citral, a monoterpene naturally present in volatile oils of Litsea cubeba, Cymbopogon flexuosus and citrus peel, can enhance disease resistance in postharvest citrus fruit and reduce fruit decay due to Penicillium digitatum. To clarify the defense mechanism involved in the enhancement of disease resistance, RNA-seq, metabolomics and biochemical analyses were integrated to global change in citral-treated fruit. Results showed that citral fumigation was effective at controlling citrus green mold. Citral increased the activities of phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase, followed by elevated contents of total phenolics, flavonoids, and lignin. Metabolomics revealed that citral treatment triggered accumulation of the plant hormones methyl jasmonate, abscisic acid, and indoleacetic acid, and many phenylpropanoid metabolites including curcumin, cinnamyl alcohol, hesperidin, syringin, 7-methoxyflavonol, vitexin-2-O-rhamnoside, coniferin, naringin, kaempferol-7-neohesperidoside, and trans-cinnamaldehyde. RNA-seq results revealed that the expression levels of multiple genes involved in jasmonic acid (JA) profiles and phenylpropanoid biosynthesis were markedly upregulated by citral. These findings suggest that the JA pathway is positively involved in the induced disease resistance of citrus fruit by citral, and provide a novel theoretical support by which citral fumigation manages postharvest citrus green mold.

Alterations in Satellite Cell Differentiation from Young Patients with Cerebral Palsy

Cerebral Palsy (CP) is one of the most common lifelong conditions leading to childhood physical disability, affecting approximately 1.6 in 1000 live births. Literature reported muscle alterations of CP patients in comparison to Typically Developing (TD) children such as fibrotic tissue accumulation and reduced Satellite Cell (SC) numbers with altered fusion capacity. To better understand the observed CP muscle phenotype, we quantified and investigated SC-progenitors of the Medial Gastrocnemius from young patients with CP (n=17, aged 3-9 years, GMFCS levels I-III) and age-matched TD children (n=12). We found an increased myotube diameter and a higher amount of nucleus clusters in CP-derived myotubes compared to TD-derived myotubes. Additionally, these nucleus accumulations were larger and less linear in SCs from children with CP compared to TD. Further, no altered expression levels of multiple genes associated with SC differentiation, fusion and nuclear positioning involved in other muscle disorders have been observed. In conclusion, we unprecedently quantified altered differentiation features of SCs from CP muscles with unaltered gene hallmarks of myopathies. Further research would be needed to elucidate pathophysiological mechanisms related to the altered SC properties observed in CP muscles and its impact on in vivo muscle functioning.

PilA Gene Contributes to Virulence, Motility, Biofilm Formation, and Interspecific Competition of Bacteria in Acidovorax citrulli.

Acidovorax citrulli, the causative agent of bacterial fruit blotch, can be divided into two main groups based on factors such as pathogenicity and host species preference. PilA is an important structural and functional component of type IV pili (T4P). Previous studies have found significant differences in pilA DNA sequences between group I and group II strains of A. citrulli. In this study, we characterized pilA in the group I strain pslb65 and the group II strain Aac5. pilA mutants, complementation strains, and cross-complementation strains were generated, and their biological phenotypes were analyzed to identify functional differences between pilA in the two groups. pilA deletion mutants (pslb65-ΔpilA and Aac5-ΔpilA) showed significantly reduced pathogenicity compared with the wild-type (WT) strains; pslb65-ΔpilA also completely lost twitching motility, whereas Aac5-ΔpilA only partially lost motility. In King's B medium, there were no significant differences in biofilm formation between pslb65-ΔpilA and WT pslb65, but Aac5-ΔpilA showed significantly reduced biofilm formation compared to WT Aac5. In M9 minimal medium, both mutants showed significantly lower biofilm formation compared to the corresponding WT strains, although biofilm formation was recovered in the complementation strains. The biofilm formation capacity was somewhat recovered in the cross-complementation strains but remained significantly lower than in the WT strains. The interspecies competitive abilities of pslb65-ΔpilA and Aac5-ΔpilA were significantly lower than in the WT strains; Aac5-ΔpilA was more strongly competitive than pslb65-ΔpilA, and the complementation strains recovered competitiveness to WT levels. Furthermore, the cross-complementation strains showed stronger competitive abilities than the corresponding WT strains. The relative expression levels of genes related to T4P and the type VI secretion system were then assessed in the pilA mutants via quantitative PCR. The results showed significant differences in the relative expression levels of multiple genes in pslb65-ΔpilA and Aac5-ΔpilA compared to the corresponding WT stains. This indicated the presence of specific differences in pilA function between the two A. citrulli groups, but the regulatory mechanisms involved require further study.

Genome-wide DNA methylation and transcriptome expression profiles of peripheral blood mononuclear cells in patients with systemic sclerosis with interstitial lung disease.

This study aims to investigate the genome-wide DNA methylation and transcriptome expression profiles of peripheral blood mononuclear cells (PBMCs) in patients with systemic sclerosis (SSc) with interstitial lung disease (ILD), and to analyze the effects of DNA methylation on Wnt/β-catenin and chemokine signaling pathways. PBMCs were collected from 19 patients with SSc (SSc group) and 18 healthy persons (control group). Among SSc patients, there were 10 patients with ILD (SSc with ILD subgroup) and 9 patients without ILD (SSc without ILD subgroup). The genome-wide DNA methylation and gene expression level were analyzed by using Illumina 450K methylation chip and Illumina HT-12 v4.0 gene expression profiling chip. The effect of DNA methylation on Wnt/β-catenin and chemokine signal pathways was investigated. Genome-wide DNA methylation analysis identified 71 hypermethylated CpG sites and 98 hypomethylated CpG sites in the SSc with ILD subgroup compared with the SSc without ILD subgroup. Transcriptome analysis distinguished 164 upregulated genes and 191 downregulated genes in the SSc with ILD subgroup as compared with the SSc without ILD subgroup. In PBMCs of the SSc group, 35 genes in Wnt/β-catenin signaling pathway were hypomethylated, while frizzled-1 (FZD1), mitogen-activated protein kinase 9 (MAPK9), mothers against DPP homolog 2 (SMAD2), transcription factor 7-like 2 (TCF7L2), and wingless-type MMTV integration site family, member 5B (WNT5B) mRNA expressions were upregulated as compared with the control group (all P<0.05). Compared with the SSc without ILD subgroup, the mRNA expressions of dickkopf homolog 2 (DKK2), FZD1, MAPK9 were upregulated in the SSc with ILD subgroup, but the differences were not statistically significant (all P>0.05). In PBMCs of the SSc group, 38 genes in chemokine signaling pathway were hypomethylated, while β-arrestin 1 (ARRB1), C-X-C motif chemokine ligand 10 (CXCL10), C-X-C motif chemokine ligand 16 (CXCL16), FGR, and neutrophil cytosolic factor 1C (NCF1C) mRNA expressions were upregulated as compared with the control group (all P<0.05). Compared with the SSc without ILD subgroup, the mRNA expressions of ARRB1, CXCL10, CXCL16 were upregulated in the SSc with ILD subgroup, but the differences were not statistically significant (all P>0.05). There are differences in DNA methylation and transcriptome profiles between SSc with ILD and SSc without ILD. The expression levels of multiple genes in Wnt/β- catenin and chemokine signaling pathways are upregulated, which might be associatea with the pathogenesis of SSc.

The Effect of Hydroquinidine on Proliferation and Apoptosis of TMZ-sensitive and -resistant GBM Cells.

Glioblastoma multiforme (GBM) is a lethal form of central nervous system cancer with a lack of efficient therapy options. Aggressiveness and invasiveness of the GBM result in poor prognosis and low overall survival. Therefore, the necessity to develop new anti-carcinogenic agents in GBM treatment is still a priority for researchers. Ion channels are one of the primary regulators of physiological homeostasis with additional critical roles in many essential biological processes related to cancer, such as invasion and metastasis. A multi-channel blocker, hydroquinidine (HQ), is currently in use to treat short-QT and Brugada arrhythmia syndromes. The objective of the study was to examine the alterations in survival, clonogenicity, migration, tumorigenicity, proliferation, apoptosis, and gene expression profile of temozolomide (TMZ)-sensitive and TMZ-resistant GBM cells upon HQ treatment. The possible anti-neoplastic activity of HQ on GBM cells was investigated by several widely applied cell culture methods. The IC50 values were determined using the MTT assay. Upon HQ treatment, the clonogenicity and migration capacity of cells were evaluated via colony-formation and wound healing assay, respectively. For antiproliferative and apoptotic effects, EdU and CFSE, and Annexin-V labeling were applied. Tumorigenicity level was depicted by employing soft agar assay. The expression level of multiple genes functioning in the cell cycle and apoptosis- related processes was checked utilizing qPCR. A significant anti-carcinogenic effect of HQ on TMZ-sensitive and -resistant GBM cells characterized by the increased apoptosis and decreased proliferation rate was revealed due to the altered gene expression profile related to cell cycle and cell death. In this study, the anti-carcinogenic effect of HQ has been demonstrated for the first time. Our data suggest the possible utilization of HQ to suppress the growth of GBM cells. Further studies on GBM-bearing animal models are required to assess its therapeutic potential in GBM treatment.

Impact of Quorum Sensing Signal N-3-Oxododecanoyl Homoserine Lactone on Intestinal Porcine Enterocyte Cell

Quorum sensing (QS) is an autoinducer (AI) molecules mediated signaling system in bacteria. It is generally believed that bacteria can regulate their own characteristics or virulence through OS. This study investigated the direct effects of a quorum sensing signal molecule N-3-oxododecanoyl homoserine lactone (3OC12-HSL, synonyms: OdDHL) on host cells, to further reveal the function of QS system in the interaction between bacteria and host cells. Intestinal porcine enterocyte cell line (IPEC-J2) were used as model cells, and the AHL signal molecule OdDHL was used to stimulate the cells to observe the effect of quorum sensing signals on host cells. The results showed that OdDHL had an obvious effect on the morphology of IPEC-J2 cells, and a lower concentration and shorter time of stimulation could induce cell shrinkage and rounding. MTT assay revealed that OdDHL had no effect on IPEC-J2 cell viability, suggesting that the cell morphological changes were not from signaling molecule toxicity. Using different concentrations and different exposure times of OdDHL to stimulate IPEC-J2 cells, we demonstrated that changes in cell morphology were positively correlated with the concentration of AHL and exposure time. Bacterial adhesion assay showed that OdDHL could enhance the adhesion of enteropathogenic E. coli to host cell IPEC-J2, while reducing its invasion into host cell. Fluorescent quantitative PCR and Western blot revealed that the expression of tight junction protein ZO-1 was significantly increased. The expression levels of multiple genes that related to cytoskeletons and cell junction were all regulated by OdDHL. In conclusion, OdDHL could directly affect the biological characteristics of IPEC-J2 cells such as morphology and tight junction, reduce the intestinal defences of hosts, thereby promoting the adhesion and injury of pathogenic bacteria to the intestine of piglets. This study provides a basic reference for further understanding of the pathogenic role of regulating pathogenic bacterial populations and their prevention against diseases.

Relationships between neurotransmitter receptor densities and expression levels of their corresponding genes in the human hippocampus

Neurotransmitter receptors are key molecules in signal transmission, their alterations are associated with brain dysfunction. Relationships between receptors and their corresponding genes are poorly understood, especially in humans. We combined in vitro receptor autoradiography and RNA sequencing to quantify, in the same tissue samples (7 subjects), the densities of 14 receptors and expression levels of their corresponding 43 genes in the Cornu Ammonis (CA) and dentate gyrus (DG) of human hippocampus. Significant differences in receptor densities between both structures were found only for metabotropic receptors, whereas significant differences in RNA expression levels mostly pertained ionotropic receptors. Receptor fingerprints of CA and DG differ in shapes but have similar sizes; the opposite holds true for their “RNA fingerprints”, which represent the expression levels of multiple genes in a single area. In addition, the correlation coefficients between receptor densities and corresponding gene expression levels vary widely and the mean correlation strength was weak-to-moderate. Our results suggest that receptor densities are not only controlled by corresponding RNA expression levels, but also by multiple regionally specific post-translational factors.

Correlation between Parental Transcriptome and Field Data for the Characterization of Heterosis in Chinese Cabbage.

In Chinese cabbage breeding, hybrids have made a terrific contribution due to heterosis, the superior performance of offspring compared to their inbred parents. Since the development of new, top-performing hybrids requires a large scale of human and material resources, the prediction of hybrid performance is of utmost interest to plant breeders. In our research, leaf transcriptome data from eight parents were used to investigate if they might be employed as markers to predict hybrid performance and heterosis. In Chinese cabbage, heterosis of plant growth weight (PGW) and heterosis of head weight (HW) were more obvious than other traits. The number of differential expression genes (DEGs) between parents was related to the PGW, length of the biggest outer leaf (LOL), leaf head height (LHH), leaf head width (LHW), HW, leaf number of head (LNH) and plant height (PH) of hybrids, and up-regulated DEGs number was also associated with these traits. Euclidean and binary distances of parental gene expression levels were significantly correlated with the PGW, LOL, LHH, LHW, HW and PH of hybrids. Additionally, there was a significant correlation between the parental expression levels of multiple genes involved in the ribosomal metabolic pathway and hybrid observations and heterosis in PGW, with the BrRPL23A gene showing the highest correlation with the MPH of PGW(r = 0.75). Therefore, leaf transcriptome data can preliminarily predict the hybrid performance and select parents in Chinese cabbage.

Heme biosensor-guided in vivo pathway optimization and directed evolution for efficient biosynthesis of heme

BackgroundHeme has attracted much attention because of its wide applications in medicine and food. The products of genes hemBCDEFY convert 5-aminolevulinic acid to protoporphyrin IX (PPIX; the immediate precursor of heme); protoporphyrin ferrochelatase (FECH) inserts Fe2+ into PPIX to generate heme. Biosynthesis of heme is limited by the need for optimized expression levels of multiple genes, complex regulatory mechanisms, and low enzymatic activity; these problems need to be overcome in metabolic engineering to improve heme synthesis.ResultsWe report a heme biosensor-guided screening strategy using the heme-responsive protein HrtR to regulate tcR expression in Escherichia coli, providing a quantifiable link between the intracellular heme concentration and cell survival in selective conditions (i.e., the presence of tetracycline). This system was used for rapid enrichment screening of heme-producing strains from a library with random ribosome binding site (RBS) variants and from a FECH mutant library. Through up to four rounds of iterative evolution, strains with optimal RBS intensities for the combination of hemBCDEFY were screened; we obtained a PPIX titer of 160.8 mg/L, the highest yield yet reported in shaken-flask fermentation. A high-activity FECH variant was obtained from the saturation mutagenesis library. Fed-batch fermentation of strain SH20C, harboring the optimized hemBCDEFY and the FECH mutant, produced 127.6 mg/L of heme.ConclusionWe sequentially improved the multigene biosynthesis pathway of PPIX and performed in vivo directed evolution of FECH, based on a heme biosensor, which demonstrated the effectiveness of the heme biosensor-based pathway optimization strategy and broadens our understanding of the mechanism of heme synthesis.

Pyruvate transporter BnaBASS2 impacts seed oil accumulation in Brassica napus.

Bile acid: sodium symporter family protein 2 (BASS2) is a sodium-dependent pyruvate transporter, which transports pyruvate from cytosol into plastid in plants. In this study, we investigated the function of chloroplast envelope membrane-localized BnaBASS2 in seed metabolism and seed oil accumulation of Brassica napus (B. napus). Four BASS2 genes were identified in the genome of B. napus. BnaA05.BASS2 was overexpressed while BnaA05.BASS2 and BnaC04.BASS2-1 were mutated by CRISPR in B. napus. Metabolite analysis revealed that the manipulation of BnaBASS2 caused significant changes in glycolysis-, fatty acid synthesis-, and energy-related metabolites in the chloroplasts of 31 day-after-flowering (DAF) seeds. The analysis of fatty acids and lipids in developing seeds showed that BnaBASS2 could affect lipid metabolism and oil accumulation in developing seeds. Moreover, the overexpression (OE) of BnaA05.BASS2 could promote the expression level of multiple genes involved in the synthesis of oil and the formation of oil body during seed development. Disruption of BnaA05.BASS2 and BnaC04.BASS2-1 resulted in decreasing the seed oil content (SOC) by 2.8%-5.0%, while OE of BnaA05.BASS2 significantly promoted the SOC by 1.4%-3.4%. Together, our results suggest that BnaBASS2 is a potential target gene for breeding B. napus with high SOC.

Tumor-Associated Inflammation: The Tumor-Promoting Immunity in the Early Stages of Tumorigenesis.

Tumorigenesis is a multistage progressive oncogenic process caused by alterations in the structure and expression level of multiple genes. Normal cells are continuously endowed with new capabilities in this evolution, leading to subsequent tumor formation. Immune cells are the most important components of inflammation, which is closely associated with tumorigenesis. There is a broad consensus in cancer research that inflammation and immune response facilitate tumor progression, infiltration, and metastasis via different mechanisms; however, their protumor effects are equally important in tumorigenesis at earlier stages. Previous studies have demonstrated that during the early stages of tumorigenesis, certain immune cells can promote the formation and proliferation of premalignant cells by inducing DNA damage and repair inhibition, releasing trophic/supporting signals, promoting immune escape, and activating inflammasomes, as well as enhance the characteristics of cancer stem cells. In this review, we focus on the potential mechanisms by which immune cells can promote tumor initiation and promotion in the early stages of tumorigenesis; furthermore, we discuss the interaction of the inflammatory environment and protumor immune cells with premalignant cells and cancer stem cells, as well as the possibility of early intervention in tumor formation by targeting these cellular mechanisms.

The Physiological Roles of the Exon Junction Complex in Development and Diseases.

The exon junction complex (EJC) becomes an increasingly important regulator of early gene expression in the central nervous system (CNS) and other tissues. The EJC is comprised of three core proteins: RNA-binding motif 8A (RBM8A), Mago homolog (MAGOH), eukaryotic initiation factor 4A3 (EIF4A3), and a peripheral EJC factor, metastatic lymph node 51 (MLN51), together with various auxiliary factors. The EJC is assembled specifically at exon-exon junctions on mRNAs, hence the name of the complex. The EJC regulates multiple levels of gene expression, from splicing to translation and mRNA degradation. The functional roles of the EJC have been established as crucial to the normal progress of embryonic and neurological development, with wide ranging implications on molecular, cellular, and organism level function. Dysfunction of the EJC has been implicated in multiple developmental and neurological diseases. In this review, we discuss recent progress on the EJC’s physiological roles.

Post-transcriptional regulation of ATG1 is a critical node that modulates autophagy during distinct nutrient stresses

ABSTRACT Macroautophagy/autophagy is a highly conserved nutrient-recycling pathway that eukaryotes utilize to combat diverse stresses including nutrient depletion. Dysregulation of autophagy disrupts cellular homeostasis leading to starvation susceptibility in yeast and disease development in humans. In yeast, the robust autophagy response to starvation is controlled by the upregulation of ATG genes, via regulatory processes involving multiple levels of gene expression. Despite the identification of several regulators through genetic studies, the predominant mechanism of regulation modulating the autophagy response to subtle differences in nutrient status remains undefined. Here, we report the unexpected finding that subtle changes in nutrient availability can cause large differences in autophagy flux, governed by hitherto unknown post-transcriptional regulatory mechanisms affecting the expression of the key autophagyinducing kinase Atg1 (ULK1/ULK2 in mammals). We have identified two novel post-transcriptional regulators of ATG1 expression, the kinase Rad53 and the RNA-binding protein Ded1 (DDX3 in mammals). Furthermore, we show that DDX3 regulates ULK1 expression post-transcriptionally, establishing mechanistic conservation and highlighting the power of yeast biology in uncovering regulatory mechanisms that can inform therapeutic approaches.

Abstract 2483: Expression of microRNA and mRNA in U87 glioblastoma cells transfected with PTEN

Abstract Background: U87 glioblastoma cells (ATCC HTB-14) were transfected with a plasmid containing the wild type PTEN gene. Untransfected U87 cells and U87 cells transfected with a plasmid containing only a fluorescent marker served as controls. Methods: Cells were assessed for neurosphere formation and growth in soft agar. Genes were assessed for expression of microRNA and messenger RNA by the NanoString nCounter platform. Results: The PTEN transfectants exhibited reduced neurosphere formation and diminished growth in soft agar. The PTEN transfectants exhibited a 10-fold or greater change in 101 of 799 microRNA species assessed compared to untransfected cells. The change in microRNA expression was strongly influenced by growth in hypoxic conditions. Expression of mRNA was altered in 260 of 760 genes assessed with 8% of the genes showing a 10-fold or greater difference in expression level. A detailed summary of the NanoString results is provided. Conclusions: (1) The PTEN transfectants demonstrate growth characteristics in vitro suggestive of decreased tumorigenicity. (2) The expression level of multiple genes is affected in the PTEN transfectants. (3) Hypoxic conditions bring out the greatest change in the expression level of microRNA in the PTEN transfected cells. Citation Format: David Stefanik, Sidney Goldblatt, Rick Jordan. Expression of microRNA and mRNA in U87 glioblastoma cells transfected with PTEN [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2483.

Sporophytic control of anther development and male fertility by glucose-6-phosphate/phosphate translocator 1 (OsGPT1) in rice

Coordination between the sporophytic tissue and the gametic pollen within anthers is tightly controlled to achieve the optimal pollen fitness. Glucose-6-phosphate/phosphate translocator (GPT) transports glucose-6-phosphate, a key precursor of starch and/or fatty acid biosynthesis, into plastids. Here, we report the functional characterization of OsGPT1 in the rice anther development and pollen fertility. Pollen grains from homozygous osgpt1 mutant plants fail to accumulate starch granules, resulting in pollen sterility. Genetic analyses reveal a sporophytic effect for this mutation. OsGPT1 is highly expressed in the tapetal layer of rice anther. Degeneration of the tapetum, an important process to provide cellular contents to support pollen development, is impeded in osgpt1 plants. In addition, defective intine and exine are observed in the pollen from osgpt1 plants. Expression levels of multiple genes that are important to tapetum degeneration or pollen wall formation are significantly decreased in osgpt1 anthers. Previously, we reported that AtGPT1 plays a gametic function in the accumulation of lipid bodies in Arabidopsis pollen. This report highlights a sporophytic role of OsGPT1 in the tapetum degeneration and pollen development. The divergent functions of OsGPT1 and AtGPT1 in pollen development might be a result of their independent evolution after monocots and dicots diverged.

Dexmedetomidine promotes inflammation resolving through TGF-β1 secreted by F4/80+Ly6G+ macrophage

Dexmedetomidine (DEX) is a highly selective α2-adrenoceptor agonist, which can regulate inflammatory responses. However, whether DEX interferes with the inflammation resolving remains unclear. Here, we reported the effects of DEX on zymosan-induced generalized inflammation in mice during resolution. Mice were administered intraperitoneally with DEX after the initiation of sepsis. The resolution interval (Ri), a vital resolution indice, decreased from twelve hours to eight hours after the administration of DEX. The induction of peritoneal pro-inflammatory interleukin [IL] - 1β and tumour necrosis factor-α (TNF-α) appeared to be inhibited. Of interest, the anti-inflammatory transforming growth factor-β1 (TGF-β1) but not IL-10 levels were up-regulated at twenty-four hours in the DEX group along with 1.0 mg/mice zymosan A (ZyA) treatment. The expression levels of multiple genes related to protective immune processes and clearance functions were detected and revealed the same trends. DEX markedly increased the F4/80+Ly6G+ macrophage population. Additionally, the adequate apoptotic neutrophil clearance from injury after DEX installation could be reverse by opsonization or co-instillation of TGF-β1 neutralizing antibody in vivo, promoting the inflammation-resolution programs. In conclusion, DEX post-treatment, via the increase of F4/80+Ly6G+ macrophages, provokes further secretion of TGF-β1, leading to the attenuated cytokine storm and accelerated inflammation resolving.

Screening and Genetic Network Analysis of Genes Involved in Freezing and Thawing Resistance in DaMDHAR-Expressing Saccharomyces cerevisiae Using Gene Expression Profiling.

The cryoprotection of cell activity is a key determinant in frozen-dough technology. Although several factors that contribute to freezing tolerance have been reported, the mechanism underlying the manner in which yeast cells respond to freezing and thawing (FT) stress is not well established. Therefore, the present study demonstrated the relationship between DaMDHAR encoding monodehydroascorbate reductase from Antarctic hairgrass Deschampsia antarctica and stress tolerance to repeated FT cycles (FT2) in transgenic yeast Saccharomyces cerevisiae. DaMDHAR-expressing yeast (DM) cells identified by immunoblotting analysis showed high tolerance to FT stress conditions, thereby causing lower damage for yeast cells than wild-type (WT) cells with empty vector alone. To detect FT2 tolerance-associated genes, 3′-quant RNA sequencing was employed using mRNA isolated from DM and WT cells exposed to FT (FT2) conditions. Approximately 332 genes showed ≥2-fold changes in DM cells and were classified into various groups according to their gene expression. The expressions of the changed genes were further confirmed using western blot analysis and biochemical assay. The upregulated expression of 197 genes was associated with pentose phosphate pathway, NADP metabolic process, metal ion homeostasis, sulfate assimilation, β-alanine metabolism, glycerol synthesis, and integral component of mitochondrial and plasma membrane (PM) in DM cells under FT2 stress, whereas the expression of the remaining 135 genes was partially related to protein processing, selenocompound metabolism, cell cycle arrest, oxidative phosphorylation, and α-glucoside transport under the same condition. With regard to transcription factors in DM cells, MSN4 and CIN5 were activated, but MSN2 and MGA1 were not. Regarding antioxidant systems and protein kinases in DM cells under FT stress, CTT1, GTO, GEX1, and YOL024W were upregulated, whereas AIF1, COX2, and TRX3 were not. Gene activation represented by transcription factors and enzymatic antioxidants appears to be associated with FT2-stress tolerance in transgenic yeast cells. RCK1, MET14, and SIP18, but not YPK2, have been known to be involved in the protein kinase-mediated signalling pathway and glycogen synthesis. Moreover, SPI18 and HSP12 encoding hydrophilin in the PM were detected. Therefore, it was concluded that the genetic network via the change of gene expression levels of multiple genes contributing to the stabilization and functionality of the mitochondria and PM, not of a single gene, might be the crucial determinant for FT tolerance in DaMDAHR-expressing transgenic yeast. These findings provide a foundation for elucidating the DaMDHAR-dependent molecular mechanism of the complex functional resistance in the cellular response to FT stress.

Metabolism, morphology and transcriptome analysis of oscillatory behavior of Clostridium butyricum during long-term continuous fermentation for 1,3-propanediol production

BackgroundOscillation is a special cell behavior in microorganisms during continuous fermentation, which poses threats to the output stability for industrial productions of biofuels and biochemicals. In previous study, a spontaneous oscillatory behavior was observed in Clostridium butyricum-intensive microbial consortium in continuous fermentation for 1,3-propanediol (1,3-PDO) production from glycerol, which led to the discovery of oscillation in species C. butyricum.ResultsSpontaneous oscillations by C. butyricum tended to occur under glycerol-limited conditions at low dilution rates. At a glycerol feed concentration of 88 g/L and a dilution rate of 0.048 h−1, the oscillatory behavior of C. butyricum was observed after continuous operation for 146 h and was sustained for over 450 h with an average oscillation period of 51 h. During oscillations, microbial glycerol metabolism exhibited dramatic periodic changes, in which productions of lactate, formate and hydrogen significantly lagged behind that of other products including biomass, 1,3-PDO and butyrate. Analysis of extracellular oxidation–reduction potential and intracellular ratio of NAD+/NADH indicated that microbial cells experienced distinct redox changes during oscillations, from oxidized to reduced state with decreasing of growth rate. Meanwhile, C. butyricum S3 exhibited periodic morphological changes during oscillations, with aggregates, elongated shape, spores or cell debris at the trough of biomass production. Transcriptome analysis indicated that expression levels of multiple genes were up-regulated when microbial cells were undergoing stress, including that for pyruvate metabolism, conversion of acetyl-CoA to acetaldehyde as well as stress response.ConclusionThis study for the first time systematically investigated the oscillatory behavior of C. butyricum in aspect of occurrence condition, metabolism, morphology and transcriptome. Based on the experimental results, two hypotheses were put forward to explain the oscillatory behavior: disorder of pyruvate metabolism, and excessive accumulation of acetaldehyde.