Assessing the genetic diversity of tobacco germplasm using intersimple sequence repeat and inter-retrotransposon amplification polymorphism markers

The genetic diversity of 118 tobacco accessions, including flue‐cured tobacco, sun‐/air‐cured tobacco, burley tobacco, oriental tobacco and wild tobacco, was characterised using intersimple sequence repeat (ISSR) and inter‐retrotransposon amplification polymorphism (IRAP) markers. ISSR and IRAP banding patterns and genetic distance (GD) values showed the low level of genetic diversity within and among cultivated tobacco types. There was higher GD and average heterozygosity among wild tobacco types than those among cultivated tobacco. Genetic diversity of tobacco germplasm was low, with a high level of genetic identity (>0.77) between the different types. However, neighbour‐joining cluster analysis of marker‐based GDs showed that the accessions from the same tobacco type, as classified by manufacturing quality traits, were nearly clustered into the same group. These results will help in the formulation of appropriate strategies for variety improvement in tobacco, and ISSR and IRAP markers of the genetic diversity will contribute to further study and improvement of tobacco.     

The Protective Effect of Selenium on Bovine Mammary Epithelial Cell Injury Caused by Depression of Thioredoxin Reductase

To elucidate the effect of selenium (Se) on antioxidant function of mammary glands in dairy cows and the underlying mechanism, an experiment was conducted using a single-factor completely randomized design study. Bovine mammary epithelial cells (BMECs) were randomly divided into four groups: control, Se treatment, 2,4-dinitrochlorobenzene (DNCB) inhibition, and Se prevention. Treatment of BMECs with Se was found to significantly reverse decreased cell proliferation and the expression of thioredoxin reductase (TrxR) after DNCB exposure. DNCB-induced activation of apoptosis signaling kinase-1 (ASK-1), which activates the mitogen-activated protein kinase (MAPK) pathway, was reduced in BMECs treated with Se. Additionally, our results indicated that Se treatment resulted in lower intracellular accumulation of arachidonic acid (ARA) and 15-hydroperoxyeicosatetraenoic acid (15-HPETE) due to suppressed expression of cytosolic phospholipase A₂ (cPLA₂) regulated by p38MAPK and c-Jun N-terminal kinase (JNK) in DNCB-stimulated BMECs. Taken together, these findings suggest that Se treatment improved the antioxidant function of dairy cow mammary glands and protected cells from oxidative damage primarily by increasing the activity of TrxR, inhibiting the activation of the MAPK signaling pathway, and thus decreasing the content of ARA and its related metabolites.     

Comparison of the expression of Bacillus thuringiensis full-length and N-terminally truncated vip3A gene in Escherichia coli

AIMS: Studies were performed to demonstrate the function of the putative signal peptide of Vip3A proteins in Escherichia coli. METHODS AND RESULTS: The full-length vip3A-S184 gene was isolated from a soil-isolated Bacillus thuringiensis, and the vip3AdeltaN was constructed by deleting 81 nucleotides at the 5'-terminus of vip3A-S184. Both were transformed and expressed in E. coli. About 19.2% of Vip3A-S184 proteins secreted soluble proteins and others formed inclusion bodies in the periplasmic space. In contrast, the Vip3AdeltaN was insoluble and formed inclusion bodies in the cytoplasm. Bioassay indicated that Vip3A-S184 showed different toxicity against Spodoptera exigua, Helicoverpa armigera and S. litura, but Vip3AdeltaN showed no toxicity to either of them because of the deletion of the first 27 amino acids at the N-terminus. CONCLUSIONS: The results suggest that the deleted N-terminal sequences were essential for the secretion of Vip3A-S184 protein in E. coli and might be required for toxicity. SIGNIFICANCE AND IMPACT OF THE STUDY: The function of the putative signal peptide of Vip3A protein in E. coli was investigated. These would be helpful to make clear the unknown secretion pathway of Vip3A protein in B. thuringiensis and determine the receptor-binding domain or toxic fragment of Vip3A-S184 protein.     

A misfolded form of 5S rRNA is complexed with the Ro and La autoantigens.

In both vertebrate and invertebrate cells, the 60-kDa Ro autoantigen is bound to small cytoplasmic RNAs known as Y RNAs. In Xenopus oocytes, the 60-kDa Ro protein is also complexed with a class of 5S rRNA precursors that contain internal mutations. Because these 5S rRNA precursors are processed inefficiently and degraded eventually, the Ro protein may function in a quality control pathway for 5S rRNA biosynthesis. We have investigated the sequence and secondary structure determinants in the mutant 5S rRNAs that confer binding by the 60-kDa Ro protein. The mutant 5S rRNAs fold to form an alternative helix that is required for recognition by the 60-kDa Ro protein. Mutations that disrupt the alternative helix eliminate Ro protein binding, whereas compensatory changes that restore the helix are bound efficiently by the Ro protein. When the structure of the mutant RNA was probed using dimethylsulfate and oligonucleotide-directed RNase H cleavage, the results were consistent with the formation of the alternative structure. The La protein, which is also complexed with the mutant 5S rRNA precursors, protects similar sequences from nuclease digestion as does the 60-kDa Ro protein. Thus, the binding sites for these two proteins are either nearby on the RNA, or the two proteins may be complexed through protein-protein interactions. When the human Ro protein is expressed in the yeast Saccharomyces cerevisiae, the protein binds wild-type 5S rRNA precursors, suggesting that a population of wild-type precursors also folds into the alternative structure.     

Enhancing Specific-Antibody Production to the ragB Vaccine with GITRL That Expand Tfh,IFN-γ+ T Cells and Attenuates Porphyromonas gingivalis Infection in Mice

The outer membrane protein RagB is one of the major virulence factors of the periodontal pathogen Porphyromonas gingivalis (P. gingivalis). In order to induce protective immune response against P. gingivalis infection, an mGITRL gene-linked ragB DNA vaccine (pIRES-ragB-mGITRL ) was constructed. Six-week-old female BALB/c mice were immunized with pIRES-ragB-mGITRL through intramuscular injection and then challenged by subcutaneous injection in the abdomen with P. gingivalis. RagB-specific antibody-forming cells were evaluated by an Enzyme-linked immunosorbent spot, and specific antibody was determined by enzyme-linked immunosorbent assay. In addition, the frequencies of Tfh and IFN-γ⁺ T cells in spleen were measured using flow cytometer, and the levels of IL-21 and IFN-γ mRNA or proteins were detected by real time RT-PCR or ELISA. The data showed that the mGITRL-linked ragB DNA vaccine induced higher levels of RagB-specific IgG in serum and RagB-specific antibody-forming cells in spleen. The frequencies of Tfh and IFN-γ⁺ T cells were obviously expanded in mice immunized by pIRES-ragB-mGITRL compared with other groups (pIRES or pIRES-ragB ). The levels of Tfh and IFN-γ⁺ T cells associated cytokines were also significantly increased in pIRES-ragB-mGITRL group. Therefore, the mice immunized with ragB plus mGITRL showed the stronger resistant to P. gingivalis infection and a significant reduction of the lesion size caused by P. gingivalis infection comparing with other groups. Taken together, our findings demonstrated that intramuscular injection of DNA vaccine ragB together with mGITRL induced protective immune response dramatically by increasing Tfh and IFN-γ⁺ T cells and antibody production to P. gingivalis.     

Correlations and comparisons of quantitative trait loci with family per se and testcross performance for grain yield and related traits in maize

Simultaneous improvement in grain yield and related traits in maize hybrids and their parents (inbred lines) requires a better knowledge of genotypic correlations between family per se performance (FP) and testcross performance (TP). Thus, to understand the genetic basis of yield-related traits in both inbred lines and their testcrosses, two F _2:3 populations (including 230 and 235 families, respectively) were evaluated for both FP and TP of eight yield-related traits in three diverse environments. Genotypic correlations between FP and TP, $ \hat{r}_{\text{g}} $ (FP, TP), were low (0–0.16) for grain yield per plant (GYPP) and kernel number per plant (KNPP) in the two populations, but relatively higher (0.32–0.69) for the other six traits with additive effects as the primary gene action. Similar results were demonstrated by the genotypic correlations between observed and predicted TP values based on quantitative trait loci positions and effects for FP, $ \hat{r}_{\text{g}} $ (M _FP, Y _TP). A total of 88 and 35 QTL were detected with FP and TP, respectively, across all eight traits in the two populations. However, the genotypic variances explained by the QTL detected in the cross-validation analysis were much lower than those in the whole data set for all traits. Several common QTL between FP and TP that accounted for large phenotypic variances were clustered in four genomic regions (bin 1.10, 4.05–4.06, 9.02, and 10.04), which are promising candidate loci for further map-based cloning and improvement in grain yield in maize. Compared with publicly available QTL data, these QTL were also detected in a wide range of genetic backgrounds and environments in maize. These results imply that effective selection based on FP to improve TP could be achieved for traits with prevailing additive effects.     

Effects of Dexmedetomidine and Oxycodone on Neurocognitive and Inflammatory Response After Tourniquet-Induced Ischemia–Reperfusion Injury

To evaluate the effects of dexmedetomidine (Dex) and oxycodone (Oxy) on neurocognitive and inflammatory response after tourniquet-induced ischemia–reperfusion (I/R) injury. C57/BL6 mice were used to construct the mouse model of tourniquet-induced I/R injury. Mice (n?=?48) were randomly divided into sham, I/R, Dex or Oxy group. Morris water maze test was performed to assess the spatial learning and memory function. The expression of NF-κB, TLR4, NR2B, M1 (CD68 and TNF-α) and M2 (CD206 and IL-10) polarization markers in mice hippocampus were detected by western blot or immunofluorescent staining. Spontaneous excitatory post-synaptic currents (sEPSCs) were recorded by electrophysiology. Dex treatment alleviated I/R-induced declines in learning and memory (p < 0.05), while Oxy had no significant effect on it. Compared with I/R group, Dex and Oxy treatment down-regulated the expression of NF-κB, TLR4, TNF-α and CD68 (all p < 0.05), while no significantly different was found in CD206 and IL-10. In addition, Dex treatment down-regulated the expression of NR2B and reduced the frequency and amplitude of sEPSCs in I/R model mice (all p < 0.05), while Oxy had no significant effect on them. Tourniquet-induced I/R could impair the neurocognitive function of mice. Dex treatment could alleviate I/R-induced neurocognitive disorder by inhibiting abnormal synaptic transmission in hippocampal neurons. Both Dex and Oxy could alleviate the inflammatory response likely by inhibiting the polarization of microglia toward M1 phenotype via TLR4/NF-κB pathway. Future studies are needed to further examine the effects of Dex on neurocognitive disorder after tourniquet-induced I/R injury and investigate the exact mechanism.

     

Ursolic acid prevents doxorubicin‐induced cardiac toxicity in mice through eNOS activation and inhibition of eNOS uncoupling

In addition to the known antitumour effects of ursolic acid (UA), increasing evidence indicates that this molecule plays a role in cardiac protection. In this study, the effects of ursolic acid on the heart in mice treated with doxorubicin (DOX) were assessed. The results showed that ursolic acid improved left ventrical fractional shortening (LVFS) and left ventrical ejection fraction (LVEF) of the heart, increased nitrogen oxide (NO) levels, inhibited reactive oxygen species (ROS) production and decreased cardiac apoptosis in mice treated with doxorubicin. Mechanistically, ursolic acid increased AKT and endothelial nitric‐oxide synthase (eNOS) phosphorylation levels, and enhanced eNOS expression, while inhibiting doxorubicin induced eNOS uncoupling through NADPH oxidase 4 (NOX4) down‐regulation. These effects of ursolic acid resulted in heart protection from doxorubicin‐induced injury. Therefore, ursolic acid may be considered a potential therapeutic agent for doxorubicin‐associated cardiac toxicity in clinical practice.     

Correction to: Diversity and symbiotic divergence of endophytic and non-endophytic rhizobia of Medicago sativa

The authors wish to clarify that the right Fund No. of National Natural Science Foundation of China (NSFC) is 31560666. The Fund No. in the original article was wrong. The authors apologise for this error.     

Stem Cell Transplantation Increases Antioxidant Effects in Diabetic Mice

Intra bone marrow-bone marrow transplantation (IBM- BMT) + thymus transplantation (TT) has been shown to reduce the incidence of graft versus host disease (GVHD) and restore donor-derived T cell function. In addition, an increase in insulin sensitivity occurred in db/db mice after IBM-BMT+TT treatment. Heme oxygenase (HO)-1 is a stress inducible enzyme which exert antioxidant, antiapoptotic, and immune-modulating properties. We examined whether IBM-BMT+TT could modulate the expression of HO-1 in the kidneys of db/db mice. Six-week-old db/db mice with blood glucose levels higher than 250 mg/dl were treated with IBM-BMT+TT. Six weeks later, the db/db mice showed decreased body weight, blood glucose levels and insulin, and increased plasma adiponectin levels. The upregulation of HO-1 was associated with significantly (p<0.05) increased levels of peNOS and pAKT, but decreased levels of iNOS in the kidneys of db/db mice. Plasma creatinine levels also decreased (p<0.05), and the expression of type IV collagen was improved. Thus IBM-BMT+TT unregulated the expression of HO-1, peNOS and pAKT, while decreasing iNOS levels in the kidney of db/db mice. This was associated with an improvement in renal function.