Potato purple top phytoplasma‐induced disruption of gibberellin homeostasis in tomato plants

Phytoplasmas are phloem‐inhabiting, cell wall‐less bacteria that cause numerous plant diseases worldwide. Plants infected by phytoplasmas often exhibit various symptoms indicative of hormonal imbalance. In this study, we investigated the effects of potato purple top (PPT) phytoplasma infection on gibberellin homeostasis in tomato plants. We found that PPT phytoplasma infection caused a significant reduction in endogenous levels of gibberellic acid (GA₃). The decrease in GA₃ content in diseased plants was correlated with down regulation of genes responsible for biosynthesis of bioactive GAs ( GA20ox1 and GA3ox1) and genes involved in formation of GA precursors [geranyl diphosphate synthase (GPS) and copalyldiphosphate synthase (CPS)]. Exogenous application of GA₃ at 200 µmol L^?1 was able to restore the GA content in infected plants to levels comparable to those in healthy controls, and to attenuate the characteristic ‘big bud’ symptoms induced by the phytoplasma. The interesting observation that PPT phytoplasma‐infected plants had prolonged low expression of key GA biosynthesis genes GA20ox1 and GA3ox1 under GA deficiency conditions led us to hypothesise that there was a diminished sensitivity of the GA metabolism feedback regulation, especially GA biosynthesis negative feedback regulation, in those affected plants, and such diminished sensitization in early stages of infection may represent a central element of the phytoplasma‐induced disruption of GA homeostasis and pathogenesis.     

Global Analysis of DNA Methylation Variation in Adipose Tissue from Twins Reveals Links to Disease-Associated Variants in Distal Regulatory Elements

Epigenetic modifications such as DNA methylation play a key role in gene regulation and disease susceptibility. However, little is known about the genome-wide frequency, localization, and function of methylation variation and how it is regulated by genetic and environmental factors. We utilized the Multiple Tissue Human Expression Resource (MuTHER) and generated Illumina 450K adipose methylome data from 648 twins. We found that individual CpGs had low variance and that variability was suppressed in promoters. We noted that DNA methylation variation was highly heritable (h²_median = 0.34) and that shared environmental effects correlated with metabolic phenotype-associated CpGs. Analysis of methylation quantitative-trait loci (metQTL) revealed that 28% of CpGs were associated with nearby SNPs, and when overlapping them with adipose expression quantitative-trait loci (eQTL) from the same individuals, we found that 6% of the loci played a role in regulating both gene expression and DNA methylation. These associations were bidirectional, but there were pronounced negative associations for promoter CpGs. Integration of metQTL with adipose reference epigenomes and disease associations revealed significant enrichment of metQTL overlapping metabolic-trait or disease loci in enhancers (the strongest effects were for high-density lipoprotein cholesterol and body mass index [BMI]). We followed up with the BMI SNP rs713586, a cg01884057 metQTL that overlaps an enhancer upstream of ADCY3, and used bisulphite sequencing to refine this region. Our results showed widespread population invariability yet sequence dependence on adipose DNA methylation but that incorporating maps of regulatory elements aid in linking CpG variation to gene regulation and disease risk in a tissue-dependent manner.     

IL-35 over-expression increases apoptosis sensitivity and suppresses cell growth in human cancer cells

Interleukin (IL)-35 is a novel heterodimeric cytokine in the IL-12 family and is composed of two subunits: Epstein-Barr virus-induced gene 3 (EBI3) and IL-12p35. IL-35 is expressed in T regulatory (Treg) cells and contributes to the immune suppression function of these cells. In contrast, we found that both IL-35 subunits were expressed concurrently in most human cancer cell lines compared to normal cell lines. In addition, we found that TNF-α and IFN-γ stimulation led to increased IL-35 expression in human cancer cells. Furthermore, over-expression of IL-35 in human cancer cells suppressed cell growth in vitro, induced cell cycle arrest at the G1 phase, and mediated robust apoptosis induced by serum starvation, TNF-α, and IFN-γ stimulation through the up-regulation of Fas and concurrent down-regulation of cyclinD1, survivin, and Bcl-2 expression. In conclusion, our results reveal a novel functional role for IL-35 in suppressing cancer activity, inhibiting cancer cell growth, and increasing the apoptosis sensitivity of human cancer cells through the regulation of genes related to the cell cycle and apoptosis. Thus, this research provides new insights into IL-35 function and presents a possible target for the development of novel cancer therapies.     

Gene Copy-Number Variation in Haploid and Diploid Strains of the Yeast Saccharomyces cerevisiae

The kinetochore is the macromolecular protein complex that mediates chromosome segregation. The Dsn1 component is crucial for kinetochore assembly and is phosphorylated by the Aurora B kinase. We found that Aurora B phosphorylation of Dsn1 promotes the interaction between outer and inner kinetochore proteins in budding yeast.     

A Contribution to the Pollen Morphology of Camellia (Theaceae)

The pollen morphology and ultrastructure of 20 species of Camellia (Theaceae) representing the four subgenera were examined. The pollen is tricolporate, spherical to slightly oblate or prolate, with scabrate to rugulate exine sculpturing. The tectum is traversed by perforations that vary in diameter. Pollen wall structure is tectate-columellate, the columellae fused to a footlayer. Endexine is present in all of the taxa examined. The greatest variation was observed in pollen size.     

The fate of cyanobacterial detritus in the food web of Lake Taihu: a mesocosm study using 13C and 15N labeling

The ecosystem of the highly eutrophic Lake Taihu (China) is seriously affected by recurrent cyanobacterial blooms, but little is known about the contribution made by cyanobacteria to the food web. In this study, we investigated the fate of detritus of the cyanobacterium Microcystis in the food web of Lake Taihu through a 19-day mesocosm experiment using stable-isotopic tracers of carbon (¹³C) and nitrogen (¹⁵N). ¹³C- and ¹⁵N-labeled Microcystis detritus was added to the mesocosm tanks and tracked through different elements of the food web. We found clear enrichment with both ¹³C and ¹⁵N in some zooplankton species, including Daphnia, Diaphanosoma, and Sinocalanus, which suggests that these zooplankters can utilize cyanobacterial detritus as a food source. Benthic animals, chironomid larvae and Limnodrilus, also showed pronounced increases in ¹³C and ¹⁵N, but the isotope increase was relatively smaller in the gastropods, Radix sp. and Bellamya sp., implying that they either exploited this food source differently or responded slower than the zooplankton, which apparently grew faster than the snails. Our study suggests that cyanobacterial detritus, originating almost wholly from the bloom-forming Microcystis, is an important food source for both planktonic and benthic food webs in eutrophic lakes such as Lake Taihu.     

ZmGA3ox2, a candidate gene for a major QTL,qPH3.1, for plant height in maize

Maize plant height is closely associated with biomass, lodging resistance and grain yield. Determining the genetic basis of plant height by characterizing and cloning plant height genes will guide the genetic improvement of crops. In this study, a quantitative trait locus (QTL) for plant height, qPH3.1, was identified on chromosome 3 using populations derived from a cross between Zong3 and its chromosome segment substitution line, SL15. The plant height of the two lines was obviously different, and application of exogenous gibberellin A₃ removed this difference. QTL mapping placed qPH3.1 within a 4.0 cM interval, explaining 32.3% of the phenotypic variance. Furthermore, eight homozygous segmental isolines (SILs) developed from two larger F₂ populations further narrowed down qPH3.1 to within a 12.6 kb interval. ZmGA3ox2, an ortholog of OsGA3ox2, which encodes a GA3 β‐hydroxylase, was positionally cloned. Association mapping identified two polymorphisms in ZmGA3ox2 that were significantly associated with plant height across two experiments. Quantitative RT‐PCR showed that SL15 had higher ZmGA3ox2 expression relative to Zong3. The resultant higher GA₁ accumulation led to longer internodes in SL15 because of increased cell lengths. Moreover, a large deletion in the coding region of ZmGA3ox2 is responsible for the dwarf mutant d1‐6016. The successfully isolated qPH3.1 enriches our knowledge on the genetic basis of plant height in maize, and provides an opportunity for improvement of plant architecture in maize breeding.     

Synthesis and in vitro antibacterial activity of quinolone/naphthyridone derivatives containing 3-alkoxyimino-4-(methyl)aminopiperidine scaffolds

We report herein the synthesis of a series of 7-[3-alkoxyimino-4-(methyl)aminopiperidin-1-yl]quinolone/naphthyridone derivatives. In vitro antibacterial activity of these derivatives was evaluated against representative strains, and compared with ciprofloxacin (CPFX), levofloxacin (LVFX) and gemifloxacin (GMFX). The results reveal that all of the target compounds 19a–c and 20 have considerable Gram-positive activity, although they are generally less active than the reference drugs against the Gram-negative strains with some exceptions. Especially, novel compounds 19a2, 19a4 and 19a5 were found to show strong antibacterial activity (MICs: <0.008–0.5 μg/mL) against all of the tested 15 Gram-positive strains including MRSA, LVFX- and GMFX-resistant MRSE, and CPFX-, LVFX- and GMFX-resistant MSSA.