A prominent gene activation role for C-terminal binding protein in mediating PcG/trxG proteins through Hox gene regulation

The evolutionarily conserved C-terminal binding protein (CtBP) has been well characterized as a transcriptional co-repressor. Herein, we report a previously unreported function for CtBP, showing that lowering CtBP dosage genetically suppresses Polycomb group (PcG) loss-of-function phenotypes while enhancing that of trithorax group (trxG) in Drosophila, suggesting that the role of CtBP in gene activation is more pronounced in fly development than previously thought. In fly cells, we show that CtBP is required for the derepression of the most direct PcG target genes, which are highly enriched by homeobox transcription factors, including Hox genes. Using ChIP and co-IP assays, we demonstrate that CtBP is directly required for the molecular switch between H3K27me3 and H3K27ac in the derepressed Hox loci. In addition, CtBP physically interacts with many proteins, such as UTX, CBP, Fs(1)h and RNA Pol II, that have activation roles, potentially assisting in their recruitment to promoters and Polycomb response elements that control Hox gene expression. Therefore, we reveal a prominent activation function for CtBP that confers a major role for the epigenetic program of fly segmentation and development.

Research Note: Development of a sandwich ELISA for determining plasma growth hormone concentrations in goose

Growth hormone (GH) is required for normal postnatal development in poultry; however, no immunoassay exists to assess its levels in geese plasma, hindering the study of endocrine regulation in this species. We developed a sandwich ELISA to determine the GH concentrations in the plasma of geese. Recombinant goose GH was produced using a eukaryotic expression system and purified for use as the reference standard in ELISA and the antigen for producing the polyclonal antibodies in rabbits. Rabbit anti-goose GH polyclonal antibody was used to coat the wells of the ELISA plate, and its biotinylated form served as the detection antibody. An avidin-conjugated horseradish peroxidase was used to bind the detection antibody and catalyze the chromogenic reaction of 3,3,5,5-tetramethylbenzidine and H₂O₂. A sigmoidal curve was fitted to the optical density and the log of the standard GH concentration using the four-parameter logistic model. The sensitivity of the assay was less than 0.156 ng/mL. The intra- and interassay coefficients of variation were less than 9 and 13%, respectively. The response curve of the serially diluted plasma samples from geese exhibited a good parallel relationship with that observed for the reference standards. The assay effectively detected differences in GH concentrations in plasma samples from geese at various physiological stages; thus, it will be useful for future study of their growth and metabolism.

Transcription factor OsMADS25 improves rice tolerance to cold stress

Cold stress is the limiting factor of rice growth and production, and it is important to clone cold stress tolerant genes and cultivate cold tolerance rice varieties. The MADS transcription factors play an important role in abiotic stress signaling in rice. This study showed that OsMADS25 was up-regulated by low temperature and abscisic acid (ABA), suggesting that OsMADS25 may be involved in ABA-dependent signaling. The OsMADS25 overexpression vector, pCambia1300-221-OsMADS25-Flag, was constructed and introduced into the rice variety Zhonghua 11 (ZH11) through Agrobacterium tumefacian-mediated genetic transformation. Two homozygous lines with high expression levels were selected for phenotypic identification. OsMADS25 overexpression lines show significantly improved cold stress tolerance and the sensitivity to ABA at the seedling stage of rice. Reactive oxygen species (ROS) was detected by diaminobenzidine (DAB) staining and nitroblue tetrazolium (NBT) staining. After treatment with cold stress, little ROS accumulation was observed in OsMADS25 overexpression lines compared to wild-type ZH11. In conclusion, OsMADS25 plays a role in scavenging reactive oxygen species (ROS) and could improve rice tolerance to cold stress involved in ABA-dependent pathway.

[Association between dyslipidemia and carotid plaque incidence in a research group: a prospective cohort study]

Objective: To assess the association and intensity of baseline dyslipidemia with the incidence of carotid plaque in a researchers group in China. Methods: A total of 716 researchers were enrolled in this prospective cohort study. Dyslipidemia was assessed in 2010. Follow-up study on carotid plaque was conducted in 2017. Results: Over 8 years' follow-up, 289 carotid plaque patients were identified among 716 individuals who did not have carotid plaque at baseline survey, with cumulative incidence of 40.36%. After adjustment of age, gender, BMI, waist circumference, FPG, SBP, DBP, ALT and uric acid, compared with non-dyslipidemia group, HR of carotid plaque for such populations with ≥3 types of dyslipidemia was 1.681 (95%CI: 1.090--2.593). Conclusions: Dyslipidemia might be associated with higher risk of carotid plaque, and population with ≥3 types of dyslipidemia had higher risk for carotid plaque. Prevention of dyslipidemia or reduction of types of dyslipidemia might be one of the effective precautions for prevention of carotid plaque.

Specialized features of the outer hair cell shapes in the cochlear fovea of bats

In this study, we examined the specialized features of the outer hair cells (OHCs) and the stereocilium bundles of the bat cochlear fovea. Bat cochlea hair cells were observed by scanning and transmission electron microscopy, and the auditory brainstem response thresholds were assessed. The stereocilia bundles of the OHCs were extremely short. The OHC bodies were flask-shaped and cambiform or ball-shape in the cochlear fovea. Digitations in the Deiters cells had exaggerated lengths, and cup formation of the Deiters cell, housed at the bottom of the OHC in the base of the cell, showed a specialized shape. Our results provide the first evidence that different shapes of the OHCs in the cochlea fovea are related to the high-frequency function of auditory response. Echolocating bats have cochlear morphologies that differ from those of non-echolocating animals. Bat cochlear foveae are specialized for analyzing the Doppler-shifted echoes of the first-harmonics of the CF2 component; these are overrepresented in the frequency range around the dominant harmonic of the echolocation calls of bats. However, the OHCs of the bat cochlear fovea have not been fully characterized.

Basic fibroblast growth factor promotes macaque follicle development in vitro

Fertility preservation is an important type of frontier scientific research in the field of reproductive health. The culture of ovarian cortices to i) initiate primordial follicle growth and ii) procure developing follicles for later oocyte maturation is a promising fertility preservation strategy, especially for older women or cancer patients. At present, this goal remains largely unsubstantiated in primates because of the difficulty in attaining relatively large follicles via ovarian cortex culture. To overcome this hurdle, we cultured macaque monkey ovarian cortices with FSH, kit ligand (KL), basic fibroblast growth factor (bFGF), and/or epidermal growth factor (EGF). The various factors and factor combinations promoted primordial follicle development to different extents. Notably, both bFF (bFGF, 100 ng/ml and FSH, 50 ng/ml) and KF (KL, 100 ng/ml and FSH, 50 ng/ml) contributed to the activation of primordial follicles at day 12 (D12) of culture, whereas at D18, the proportions of developing follicles were significantly higher in the bFF and KF groups relative to the other treatment groups, particularly in the bFF group. Estradiol and progesterone production were also highest in the bFF group, and primary follicle diameters were the largest. Up until D24, the bFF group still exhibited the highest proportion of developing follicles. In conclusion, the bFGF–FSH combination promotes nonhuman primate primordial follicle developmentin vitro, with the optimal experimental window within 18 days. These results provide evidence for the future success of human ovarian cortex culture and the eventual acquisition of mature human follicles or oocytes for fertility restoration.

First Report of Sclerotinia sclerotiorum Causing Sclerotinia Blight on Peanut (Arachis hypogaea) in Northeastern China

Peanut, Arachis hypogaea L., is an important source of vegetable oil and protein in China with a planting area of 5 million ha and annual production of 16.2 million metric tons. In September of 2012, typical symptoms of Sclerotinia blight were first observed on peanut in Shuangcheng, Heilongjiang Province, China. Approximately 50% of the plants in a field were infected. Symptoms began as a chlorotic wilt on the foliage and developed into necrosis of basal stems and developed very quickly in the field. In advanced stages of the disease, stems and branches became bleached and eventually died. White, fluffy mycelium and black irregular sclerotia (3.5 to 5.4 mm diameter) were observed on the infected stems. Infected branches and pegs were shredded, and most pods dropped on the soil during harvest. To isolate the causal agent of the disease, sclerotia were collected from the field. Twenty sclerotia were surface disinfected in 1% NaOCl for 3 min, rinsed three times with sterile water, placed on potato sucrose agar (PSA) with 100 μg/ml streptomycin, and then incubated at 22°C in the dark for 10 days. Fungal DNA was extracted from mycelia with a TIANGEN DNAsecure Plant Kit (Beijing) and amplified by PCR with the universal fungal primer ITS1 and ITS4. PCR products of five replicates were sequenced and subjected to an NCBI BLAST search. The BLAST search revealed that our sequences (GenBank Accession No. KC935388) had 100% identity with reported sequences of Sclerotinia sclerotiorum. The isolates were identified as S. sclerotiorum (Lib.) de Bary based on mycelia, sclerotia, and rDNA sequence analysis. To conduct pathogenicity tests, nine potted peanut plants (1 month old) were each inoculated with a 5-mm-diameter disk of colonized PSA by placing the inoculum on the base of the stem. Plants were inoculated with a plug of non-colonized PSA as controls. All inoculated plants were covered with a plastic bag for 5 days to maintain high humidity and incubated at 22 to 24°C in the growth chamber with a 12-h photoperiod. After 2 days, the inoculated plants showed water-soaked brown symptoms on the stem base and whole plants wilted after 5 days under high moisture conditions. The symptoms were identical to those observed on peanut plants in Shuangcheng, Heilongjiang Province, whereas the control plants remained symptom-free. Re-isolation of the fungus from the inoculated plants confirmed that the causal agent was S. sclerotiorum. S. sclerotiorum has been reported on peanut in the United States and Argentina (1,2,3). To our knowledge, this is the first report of S. sclerotiorum as a pathogen causing Sclerotinia blight on peanut in northeastern China. References: (1) A. Marinelli et al. Int. J. Pest Manage. 44:251, 1998. (2) J. E. Woodward et al. Plant Dis. 90:111, 2006. (3) J. E. Woodward et al. Plant Dis. 92:1468, 2008.

Nucleotide sequence analyses of genomic RNAs of Peanut stunt virus Mi, the type strain representative of a novel PSV subgroup from China

The complete nucleotide sequence of Peanut stunt virus strain Mi (PSV-Mi) from China was determined and compared to other viruses of the genus Cucumovirus. The tripartite genome of PSV-Mi encoded five open reading frames (ORFs) typical of cucumoviruses. Distance analyses of four ORFs indicated that PSV-Mi differed sufficiently in nucleotide sequence from other PSV strains of subgroups I and II to warrant establishment of a third subgroup of PSV.