Effect of Bacillus mesonae H20-5 Treatment on Rhizospheric Bacterial Community of Tomato Plants under Salinity Stress

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.     

A role for metaphase spindle elongation forces in correction of merotelic kinetochore attachments

During mitosis, equal segregation of chromosomes depends on proper kinetochore-microtubule attachments. Merotelic kinetochore orientation, in which a single kinetochore binds microtubules from both spindle poles [1], is a major cause of chromosome instability [2], which is commonly observed in solid tumors [3, 4]. Using the fission yeast Schizosaccharomyces pombe, we show that a proper force balance between kinesin motors on interpolar spindle microtubules is critical for correcting merotelic attachments. Inhibition of the plus-end-directed spindle elongation motors kinesin-5 (Cut7) and kinesin-6 (Klp9) reduces spindle length, tension at kinetochores, and the frequency of merotelic attachments. In contrast, merotely is increased by deletion of the minus-end-directed kinesin-14 (Klp2) or overexpression of Klp9. Also, Cdk1 regulates spindle elongation forces to promote merotelic correction by phosphorylating and inhibiting Klp9. The role of spindle elongation motors in merotelic correction is conserved, because partial inhibition of the human kinesin-5 homolog Eg5 using the drug monastrol reduces spindle length and lagging chromosome frequency in both normal (RPE-1) and tumor (CaCo-2) cells. These findings reveal unexpected links between spindle forces and correction of merotelic attachments and show that pharmacological manipulation of spindle elongation forces might be used to reduce chromosome instability in cancer cells.     

Reduction of chronic graft injury with a new HTK-based preservation solution in a murine heart transplantation model

Objective

Aim of this study was to evaluate a new histidine-tryptophan-ketoglutarate (HTK)-based preservation solution on chronic isograft injury in comparison to traditional HTK solution.

Methods

Hearts of C57BL/6J (H-2b) mice were stored for 15 h in 0–4 °C cold preservation solution and then transplanted heterotopically into C57BL/6J (H-2b) mice. Three groups were evaluated: HTK, the base solution of a new preservation solution and hearts without cold ischemia (control). Time to restoration of heartbeat was measured (re-beating time). Strength of the heartbeat was palpated daily and scored on a 4-level scale (palpation score). Animals were sacrificed after 60 days of observation (24 h for TGF-β expression). The transplanted hearts were evaluated histologically for myocardial damage, vasculopathy and interstitial fibrosis. TGF-β expression was assessed immunohistologically. All investigators were blinded to the groups. ANOVA and LSD post hoc test were used for statistical analysis.

Results

The re-beating time was significantly shorter in hearts stored in the new solution (10.3 ± 2.6 min vs. HTK 14.2 ± 4.1 min; p < 0.05). The palpation score was significantly higher in hearts stored in the new solution (2.3 ± 0.4 vs. HTK 1.6 ± 0.5; p < 0.01). Hearts stored in the new solution showed a lower myocardial injury score (1.8 ± 0.2 vs. HTK 2.2 ± 0.7), less interstitial fibrosis (4.8 ± 1.9% vs. HTK 8.5 ± 3.8%, p < 0.05), less vasculopathy (14.7 ± 6.9% vs. 22.0 ± 23.2%; p = 0.06) and lower TGF-β1-expression (6.6 ± 1.4% vs. HTK 12.0 ± 4.6%).

Conclusion

The new HTK-based solution reduces the chronic isograft injury. This protective effect is likely achieved through several modifications and supplements into the new solution like N-acetyl-l-histidine, glycine, alanine, arginine and sucrose.     

The influence of cholesterol and lipid metabolism on host cell structure and hepatitis C virus replication.

The hepatitis C virus (HCV) replicates on a membrane protein complex composed of viral proteins, replicating RNA, and altered cellular membranes. Small-molecule inhibitors of cellular lipid-cholesterol metabolism such as 25-hydroxycholesterol, cerulenin, lovastatin, and GGTI-286 all show a negative effect on HCV replication. Perturbation of host cell lipid and cholesterol metabolism can disrupt replication complexes by altering membranous structures where replication occurs. Changes in cholesterol and (or) lipid composition can have a general effect on membrane structure. Alternatively, metabolic changes can exert a more subtle influence over replication complexes by altering localization of host proteins through alterations in lipid anchoring. Here, we use Huh-7 cells harboring subgenomic HCV replicons to demonstrate that 25-hydroxycholesterol, cerulenin, lovastatin, and GGTI-286 do not disrupt the membranous web where replication occurs, whereas cholesterol-depleting agents such as beta-cyclodextrin do. Cellular imaging suggests that the HCV RNA can remain associated with subcellular compartments connected with replication complexes in the presence of metabolic inhibitors. Therefore, at least 2 different molecular mechanisms are possible for the inhibition of HCV replication through the modulation of cellular lipid and cholesterol metabolism.     

Blastocysts derivation from somatic cell fusion with premature oocytes (prematuration somatic cell fusion)

This study was undertaken to investigate the development of immature oocytes after their fusion with male somatic cells expressing red fluorescence protein (RFP). RFP‐expressing cells were fused with immature oocytes, matured in vitro and then parthenogenetically activated. Somatic nuclei showed spindle formation, 1st polar body extrusion after in vitro maturation and protruded the 2nd polar body after parthenogenetic activation. RFP was expressed in the resultant embryos; two‐cell stage and blastocysts. Chromosomal analysis showed aneuploidy in 81.82% of the resulting blastocysts while 18.18% of the resulting blastocysts were diploid. Among eight RFP‐expressing blastocysts, Xist mRNAs was detected in six while Sry mRNA was detected in only one blastocyst. We propose “prematuration somatic cell fusion” as an approach to generate embryos using somatic cells instead of spermatozoa. The current approach, if improved, would assist production of embryos for couples where the male partner is sterile, however, genetic and chromosomal analysis of the resultant embryos are required before transfer to the mothers.     

Nitrogen and phosphorus addition differentially enhance seed production of dominant species in a temperate steppe

Previous studies have demonstrated changes in plant growth and reproduction in response to nutrient availability, but responses of plant growth and reproduction to multiple levels of nutrient enrichment remain unclear. In this study, a factorial field experiment was performed with manipulation of nitrogen (N) and phosphorus (P) availability to examine seed production of the dominant species, Stipa krylovii, in response to N and P addition in a temperate steppe. There were three levels of N and P addition in this experiment, including no N addition (0 g N m⁻² year⁻¹), low N addition (10 g N m⁻² year⁻¹), and high N addition (40 g N m⁻² year⁻¹) for N addition treatment, and no P addition (0 g P m⁻² year⁻¹), low P addition (5 g P m⁻² year⁻¹), and high P addition (10 g P m⁻² year⁻¹) for P addition treatment. Low N addition enhanced seed production by 814%, 1371%, and 1321% under ambient, low, and high P addition levels, respectively. High N addition increased seed production by 2136%, 3560%, and 3550% under ambient, low, and high P addition levels, respectively. However, P addition did not affect seed production in the absence of N addition, but enhanced it under N addition. N addition enhanced seed production mainly by increasing the tiller number and inflorescence abundance per plant, whereas P addition stimulated it by decreasing the plant density yet stimulating height of plants and their seed number per inflorescence. Our results indicate seed production is not limited by P availability but rather by N availability in the temperate steppe, whereas seed production will be increased by P addition when N availability is improved. These findings enable a better understanding of plant reproduction dynamics in the temperate steppe under intensified nutrient enrichment and can inform their improved management in the future.     

Changes in Glial Cell Line-derived Neurotrophic Factor Expression in the Rostral and Caudal Stumps of the Transected Adult Rat Spinal Cord

Limited information is available regarding the role of endogenous Glial cell line-derived neurotrophic factor (GDNF) in the spinal cord following transection injury. The present study investigated the possible role of GDNF in injured spinal cords following transection injury (T₉–T₁₀) in adult rats. The locomotor function recovery of animals by the BBB (Basso, Beattie, Bresnahan) scale score showed that hindlimb support and stepping function increased gradually from 7 days post operation (dpo) to 21 dpo. However, the locomotion function in the hindlimbs decreased effectively in GDNF-antibody treated rats. GDNF immunoreactivty in neurons in the ventral horn of the rostral stump was stained strongly at 3 and 7 dpo, and in the caudal stump at 14 dpo, while immunostaining in astrocytes was also seen at all time-points after transection injury. Western blot showed that the level of GDNF protein underwent a rapid decrease at 7 dpo in both stumps, and was followed by a partial recovery at a later time-point, when compared with the sham-operated group. GDNF mRNA-positive signals were detected in neurons of the ventral horn, especially in lamina IX. No regenerative fibers from corticospinal tract can be seen in the caudal segment near the injury site using BDA tracing technique. No somatosensory evoked potentials (SEP) could be recorded throughout the experimental period as well. These findings suggested that intrinsic GDNF in the spinal cord could play an essential role in neuroplasticity. The mechanism may be that GDNF is involved in the regulation of local circuitry in transected spinal cords of adult rats.     

Identification of a stable quantitative trait locus for percentage grains with white chalkiness in rice (Oryza sativa)

High chalkiness is a major problem in many rice-producing areas of the world, especially in hybrid rice (Oryza sativa L.) in China. We previously showed a major quantitative trait locus for the percentage of grains with white chalkiness (QTLqPGWC-8) in the interval G1149-R727 on chromosome 8 using a chromosome segment substitution line (CSSL). Here, we selected the line-CSSL50 harboring the QTLqPGWC-8 allele from the CSSLs derived from a cross between Asominori (as a recurrent parent) and IR24 (as a donor parent), which had higher percentage chalkiness, markedly different from that of Asominori. There were also significant differences in starch granules, appearance of amylose content (AAC) and milling qualities between Asominori and CSSL50, but not in grain size or thousand grain weight (TGW). The BC(4) F(2) and BC(4) F(3) populations from a cross between CSSL50 and Asominori were used for fine mapping of qPGWC-8. We narrowed down the location of this QTL to a 142 kb region between Indel markers 8G-7 and 8G-9. QTLqPGWC-8 accounted for 50.9% of the difference in PGWC between the parents. The markers tightly linked to qPGWC-8 should facilitate cloning of the gene underlying this QTL and will be of value for marker-assisted selection in breeding rice varieties with better grain quality.     

Rheumatoid Arthritis Increases the Risk of Nontuberculosis Mycobacterial Disease and Active Pulmonary Tuberculosis

Background

Few studies have examined the association of rheumatoid arthritis (RA) with nontuberculosis mycobacterium (NTM) disease and pulmonary tuberculosis (PTB).

Methods

We identified 29 131 patients with RA from the catastrophic illness registry who were diagnosed from 1998–2008; 116 524 patients without RA from inpatient data files were randomly frequency matched according to sex, age, and index year and used as a comparison group. Both groups were followed-up until the end of 2010 to measure the incidence of NTM disease and active PTB. We analyzed the risk of NTM disease and active PTB using the Cox proportional hazards regression models, controlling for sex, age, and Charlson comorbidity index (CCI).

Results

The incidence of NTM disease was 4.22 times greater in the RA group than in the non-RA group (1.91 vs 0.45 per 10,000 person-years). The incidence of PTB was 2.99 times greater in the RA group than in the non-RA group (25.3 vs 8.46 per 10,000 person-years). After adjusting for age, sex, and CCI, the adjusted hazard ratios (HRs) of NTM disease and active PTB for the RA group were 4.17 (95% CI = 2.61–6.65) and 2.87 (95% CI = 2.55–3.23), respectively, compared with the non-RA group. In the first 2 years of follow-up, the RA group yielded corresponding adjusted HRs of 4.98 and 3.39 compared with the non-RA group. The follow-up time-specific RA group to the non-RA group HR of both the NTM disease and active PTB varied.

Conclusion

This study can serve as a reference for clinical physicians to increase awareness regarding the detection of NTM disease and active PTB in RA patients among the any stage of the clinical course even without CCI.