DNA methylation drives hematopoietic stem cell aging phenotypes after proliferative stress.

Aging of hematopoietic stem cells (HSCs) is implicated in various aging phenotypes, including immune dysfunction, anemia, and malignancies. The role of HSC proliferation in driving these aging phenotypes, particularly under stress conditions, remains unclear. Therefore, we induced forced replications of HSCs in vivo by a cyclical treatment with low-dose fluorouracil (5FU) and examined the impact on HSC aging.

A self-locking mechanism of the frog-legged beetle Sagra femorata.

Insect legs play a crucial role in various modes of locomotion, including walking, jumping, swimming, and other forms of movement. The flexibility of their leg joints is critical in enabling various modes of locomotion. The frog-legged leaf beetle Sagra femorata possesses remarkably enlarged hind legs, which are considered to be a critical adaptation that enables the species to withstand external pressures.

The Morphological Transformation of the Thorax during the Eclosion of (Diptera: Drosophilidae).

The model organism , as a species of Holometabola, undergoes a series of transformations during metamorphosis. To deeply understand its development, it is crucial to study its anatomy during the key developmental stages. We describe the anatomical systems of the thorax, including the endoskeleton, musculature, nervous ganglion, and digestive system, from the late pupal stage to the adult stage, based on micro-CT and 3D visualizations.

The morphology and spectral characteristics of the compound eye of (Selman & Vogt, 1971) (Coleoptera, Chrysomelidae, Galerucinae, Alticini).

The first exploratory study was conducted on the compound eye morphology and spectral characteristics of (Selman & Vogt, 1971) to clarify its eye structure and its spectral sensitivity. Scanning electron microscopy, paraffin sectioning, and transmission electron microscopy revealed that has apposition compound eyes with both eucones and open rhabdom. The micro-computed tomography (CT) results after 3D reconstruction demonstrated the precise position of the compound eyes in the insect's head and suggested that the visual range was mainly concentrated in the front and on both sides of the head.

Tristetraprolin overexpression drives hematopoietic changes in young and middle-aged mice generating dominant mitigating effects on induced inflammation in murine models.

Tristetraprolin (TTP), encoded by Zfp36 in mice, is one of the best-characterized tandem zinc-finger mRNA binding proteins involved in mRNA deadenylation and decay. TTPΔARE mice lack an AU-rich motif in the 3'-untranslated regions of TTP mRNA, leading to increased TTP mRNA stability and more TTP protein, resulting in elevated mRNA decay rates of TTP targets. We examined the effect of TTP overexpression on the hematopoietic system in both young and middle-aged mice using TTPΔARE mice and found alterations in blood cell frequencies, with loss of platelets and B220 cells and gains of eosinophils and T cells.

Structural stabilization of honeybee wings based on heterogeneous stiffness.

Structural stabilization for a membrane structure under high-frequency vibration is still a recognized problem. In nature, honeybee wings with non-uniform material properties demonstrate excellent anti-interference ability. However, the correlation between the structural stabilization and mechanical properties of insect wings has not been completely verified.

Jumping of flea beetles onto inclined platforms.

The flea beetle, Altica cirsicola, escapes predators by jumping and landing in a dense maze of leaves. How do they land on such varied surfaces? In this experimental study, we filmed the take-off, flight, and landing of flea beetles on a configurable angled platform. We report three in-flight behaviors: winged, wingless, and an intermediate winged mode.

Cancer co-opts differentiation of B-cell precursors into macrophage-like cells.

We have recently reported that some cancers induce accumulation of bone marrow (BM) B-cell precursors in the spleen to convert them into metastasis-promoting, immunosuppressive B cells. Here, using various murine tumor models and samples from humans with breast and ovarian cancers, we provide evidence that cancers also co-opt differentiation of these B-cell precursors to generate macrophage-like cells (termed B-MF). We link the transdifferentiation to a small subset of CSF1R Pax5 cells within BM pre-B and immature B cells responding to cancer-secreted M-CSF with downregulation of the transcription factor Pax5 via CSF1R signaling.

Inside the coupling of ladybird beetle elytra: elastic setae can facilitate swift deployment.

The ladybird beetle (Coccinella septempunctata) is known for swift deployment of its elytra, an action that requires considerable power. However, actuation by thoracic muscles alone may be insufficient to deploy elytra at high speed because the maximum mechanical power that elytral muscles can produce is only 70% of that required for initiation of deployment. Nevertheless, the elytra open rapidly, within 3 ms in the initial phase, at a maximum angular velocity of 66.

Rhizobial HmuS as a heme-binding factor is required for optimal symbiosis between Mesorhizobium amorphae CCNWGS0123 and Robinia pseudoacacia.

Nitrogen-fixing root nodules are formed by symbiotic association of legume hosts with rhizobia in nitrogen-deprived soils. Successful symbiosis is regulated by signals from both legume hosts and their rhizobial partners. HmuS is a heme degrading factor widely distributed in bacteria, but little is known about the role of rhizobial hmuS in symbiosis with legumes.

NAD augmentation with nicotinamide riboside improves lymphoid potential of Atm and old mice HSCs.

NAD supplementation has significant benefits in compromised settings, acting largely through improved mitochondrial function and DNA repair. Elevating NAD to physiological levels has been shown to improve the function of some adult stem cells, with implications that these changes will lead to sustained improvement of the tissue or system. Here, we examined the effect of elevating NAD levels in models with reduced hematopoietic stem cell (HSC) potential, ATM-deficient and aged WT mice, and showed that supplementation of nicotinamide riboside (NR), a NAD precursor, improved lymphoid lineage potential during supplementation.

Gene body methylation safeguards ribosomal DNA transcription by preventing PHF6-mediated enrichment of repressive histone mark H4K20me3.

DNA methylation shows complex correlations with gene expression, and the role of promoter hypermethylation in repressing gene transcription has been well addressed. Emerging evidence indicates that gene body methylation promotes transcription; however, the underlying mechanisms remain to be further investigated. Here, using methylated DNA immunoprecipitation sequencing (MeDIP-seq), bisulfite genomic sequencing, and immunofluorescent labeling, we show that gene body methylation is indeed positively correlated with rRNA gene (rDNA) transcription.

A taxonomic study on Themus (Telephorops) davidis species-group (Coleoptera, Cantharidae), with description of a new species from China.

Themus (Telephorops) davidis species-group is redefined and we present a catalogue, identification key and distribution map for this group. Some previously known species are redescribed and we provide new illustrations of female internal genitalia, abdominal sternite VIII and/or aedeagus. Further, we report new distribution data.

Type III secretion systems impact Mesorhizobium amorphae CCNWGS0123 compatibility with Robinia pseudoacacia.

Rhizobia and legume plants are famous mutualistic symbiosis partners who provide nitrogen nutrition to the natural environment. Rhizobial type III secretion systems (T3SSs) deliver effectors that manipulate the metabolism of eukaryotic host cells. Mesorhizobium amorphae CCNWGS0123 (GS0123) contains two T3SS gene clusters, T3SS-I and T3SS-II.

Metastasis-related methyltransferase 1 (Merm1) represses the methyltransferase activity of Dnmt3a and facilitates RNA polymerase I transcriptional elongation.

Stimulatory regulators for DNA methyltransferase activity, such as Dnmt3L and some Dnmt3b isoforms, affect DNA methylation patterns, thereby maintaining gene body methylation and maternal methylation imprinting, as well as the methylation landscape of pluripotent cells. Here we show that metastasis-related methyltransferase 1 (Merm1), a protein deleted in individuals with Williams-Beuren syndrome, acts as a repressive regulator of Dnmt3a. Merm1 interacts with Dnmt3a and represses its methyltransferase activity with the requirement of the binding motif for S-adenosyl-L-methionine.

TGF-β signaling alters H4K20me3 status via miR-29 and contributes to cellular senescence and cardiac aging.

Cellular senescence is a well-orchestrated programmed process involved in age-related pathologies, tumor suppression and embryonic development. TGF-β/Smad is one of the predominant pathways that regulate damage-induced and developmentally programmed senescence. Here we show that canonical TGF-β signaling promotes senescence via miR-29-induced loss of H4K20me3.

Genome and epigenome analysis of monozygotic twins discordant for congenital heart disease.

Background: Congenital heart disease (CHD) is the leading non-infectious cause of death in infants. Monozygotic (MZ) twins share nearly all of their genetic variants before and after birth. Nevertheless, MZ twins are sometimes discordant for common complex diseases.

Two cultivated legume plants reveal the enrichment process of the microbiome in the rhizocompartments.

The microbiomes of rhizocompartments (nodule endophytes, root endophytes, rhizosphere and root zone) in soya bean and alfalfa were analysed using high-throughput sequencing to investigate the interactions among legume species, microorganisms and soil types. A clear hierarchical filtration of microbiota by plants was observed in the four rhizocompartments - the nodule endosphere, root endosphere, rhizosphere and root zone - as demonstrated by significant variations in the composition of the microbial community in the different compartments. The rhizosphere and root zone microbial communities were largely influenced by soil type, and the nodule and root endophytes were primarily determined by plant species.

CHD4/NuRD maintains demethylation state of rDNA promoters through inhibiting the expression of the rDNA methyltransferase recruiter TIP5.

Despite the well-established fact that NuRD (nucleosome remodeling and histone deacetylase) is incapable of actively demethylating DNA, the complex is surprisingly showed to be required for the establishment of unmethylated state at promoters of ribosomal genes. But the molecular mechanism underlying how NuRD mediates unmethylation at rDNA promoters remains obscure. Here we show that NuRD directly binds to the promoter of rDNA transcription silencer TIP5 (TTF-I interacting protein 5), one of the components of nucleolar remodeling complex NoRC that silences rRNA genes by recruiting DNA methyltransferase to rDNA promoters and increasing DNA methylation.

The chromatin remodeling factor CSB recruits histone acetyltransferase PCAF to rRNA gene promoters in active state for transcription initiation.

The promoters of poised rRNA genes (rDNA) are marked by both euchromatic and heterochromatic histone modifications and are associated with two transcription factors, UBF and SL1 that nucleate transcription complex formation. Active rRNA genes contain only euchromatic histone modifications and are loaded with all components of transcriptional initiation complex including RNA polymerase I. Coupled with histone acetylation and RNA polymerase I targeting, poised promoters can be converted to active ones by ATP-dependent chromatin remodeling factor CSB for initiation of rDNA transcription.

NuRD blocks reprogramming of mouse somatic cells into pluripotent stem cells.

Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) by overexpression of a defined set of transcription factors requires epigenetic changes in pluripotency genes. Nuclear reprogramming is an inefficient process and the molecular mechanisms that reset the epigenetic state during iPSC generation are largely unknown. Here, we show that downregulation of the nucleosome remodeling and deacetylation (NuRD) complex is required for efficient reprogramming.