Construction of EMS-Induced Peanut Mutant Libraries and Identification of Pod-Related Traits Mutant Lines

Peanut (Arachis hypogaea L.) is an oil and economic crop of vital importance, and peanut pod is the key organ influencing the yield and processing quality. Hence, the Pod-related traits (PRTs) are considered as important agronomic traits in peanut breeding. To broaden the variability of PRTs in current peanut germplasms, three elite peanut cultivars were used to construct Ethyl methane sulfonate (EMS)-induced mutant libraries in this study. The optimal EMS treatment conditions for the three peanut varieties were determined. It was found that the median lethal dose (LD50) of EMS treatment varied greatly among different genotypes. Finally, the EMS-induced peanut mutant libraries were constructed and a total of 124 mutant lines for PRTs were identified and evaluated. Furthermore, “M-8070”, one of the mutant lines for pod constriction, was re-sequenced via high-throughput sequencing technology. The genome-wide variations between “M-8070” and its wild parent “Fuhua 8” (FH 8) were detected. 2994 EMS-induced single nucleotide polymorphisms (SNPs) and 1188 insertion-deletions (InDels) between “M-8070” and its wild parent were identified. The predominant SNP mutation type was C/G to T/A transitions, while the predominant InDel mutation type was “1-bp”. We analyzed the distribution of identified mutations and annotated their functions. Most of the mutations (91.68% of the SNPs and 77.69% of the InDels) were located in the intergenic region. 72 SNPs were identified in the exonic region, leading to 27 synonymous, 43 non-synonymous and 2 stop-gain variation for gene structure. 13 Indels were identified in the exonic region, leading to 4 frame-shift, 8 non-frame-shift and 1 stop-gain variations of genes. These mutations may lead to the phenotypic variation of “M-8070”. Our study provided valuable resources for peanut improvement and functional genomic research.     

Cell development of a green alga,Pleurotaenium nodosum,which was tied by a fiber

Summary Cells of a green alga,Pleurotaenium nodosum, were tied off with thin fibers, after which development of daughter semicells from the small tied mother semicells was examined with a light microscope. Semicells slightly shortened due to tying mostly developed normal sized daughter semicells with four nodes. However, semicells shorter than 1/2 the normal size developed small daughter semicells with fewer nodes. This was interpreted that the daughter semicells of shortened semicells had not enlarged sufficiently to allow formation of four nodes on the cell surface at the initial stage of node formation. The initiation of node formation was recognized as taking place in the contact region between the plasma membrane and the cell wall in plasmolyzed cells. The distance between two neighbouring contact regions was consistent at about 6 m.     

Pattern and morphogenesis of presumptive superficial mesoderm in two closely related species, Xenopus laevis and Xenopus tropicalis

The mesoderm, comprising the tissues that come to lie entirely in the deep layer, originates in both the superficial epithelial and the deep mesenchymal layers of the early amphibian embryo. Here, we characterize the mechanisms by which the superficial component of the presumptive mesoderm ingresses into the underlying deep mesenchymal layer in Xenopus tropicalis and extend our previous findings for Xenopus laevis. Fate mapping the superficial epithelium of pregastrula stage embryos demonstrates ingression of surface cells into both paraxial and axial mesoderm (including hypochord), in similar patterns and amounts in both species. Superficial presumptive notochord lies medially, flanked by presumptive hypochord and both overlie the deep region of the presumptive notochord. These tissues are flanked laterally by superficial presumptive somitic mesoderm, the anterior tip of which also appears to overlay the presumptive deep notochord. Time-lapse recordings show that presumptive somitic and notochordal cells move out of the roof of the gastrocoel and into the deep region during neurulation, whereas hypochordal cells ingress after neurulation. Scanning electron microscopy at the stage and position where ingression occurs suggests that superficial presumptive somitic cells in X. laevis ingress into the deep region as bottle cells whereas those in X. tropicalis ingress by "relamination" (e.g., [Dev. Biol. 174 (1996) 92]). In both species, the superficially derived presumptive somitic cells come to lie in the medial region of the presumptive somites during neurulation. By the early tailbud stages, these cells lie at the horizontal myoseptum of the somites. The morphogenic pathway of these cells strongly resembles that of the primary slow muscle pioneer cells of the zebrafish. We present a revised fate map of Xenopus, and we discuss the conservation of superficial mesoderm within amphibians and across the chordates and its implications for the role of this tissue in patterning the mesoderm.     

Autophagy-mediated degradation is necessary for regression of cardiac hypertrophy during ventricular unloading

Cardiac hypertrophy occurs in response to a variety of stresses as a compensatory mechanism to maintain cardiac output and normalize wall stress. Prevention or regression of cardiac hypertrophy can be a major therapeutic target. Although regression of cardiac hypertrophy occurs after control of etiological factors, the molecular mechanisms remain to be clarified. In the present study, we investigated the role of autophagy in regression of cardiac hypertrophy. Wild-type mice showed cardiac hypertrophy after continuous infusion of angiotensin II for 14 days using osmotic minipumps, and regression of cardiac hypertrophy was observed 7 days after removal of the minipumps. Autophagy was induced during regression of cardiac hypertrophy, as evidenced by an increase in microtubule-associated protein 1 light chain 3 (LC3)-II protein level. Then, we subjected cardiac-specific Atg5-deficient (CKO) and control mice (CTL) to angiotensin II infusion for 14 days. CKO and CTL developed cardiac hypertrophy to a similar degree without contractile dysfunction. Seven days after removal of the minipumps, CKO showed significantly less regression of cardiac hypertrophy compared with CTL. Regression of pressure overload-induced cardiac hypertrophy after unloading was also attenuated in CKO. These results suggest that autophagy is necessary for regression of cardiac hypertrophy during unloading of neurohumoral and hemodynamic stress.     

Apical constriction: A cell shape change that can drive morphogenesis

Biologists have long recognized that dramatic bending of a cell sheet may be driven by even modest shrinking of the apical sides of cells. Cell shape changes and tissue movements like these are at the core of many of the morphogenetic movements that shape animal form during development, driving processes such as gastrulation, tube formation, and neurulation. The mechanisms of such cell shape changes must integrate developmental patterning information in order to spatially and temporally control force production—issues that touch on fundamental aspects of both cell and developmental biology and on birth defects research. How does developmental patterning regulate force-producing mechanisms, and what roles do such mechanisms play in development? Work on apical constriction from multiple systems including Drosophila, Caenorhabditis elegans, sea urchin, Xenopus, chick, and mouse has begun to illuminate these issues. Here, we review this effort to explore the diversity of mechanisms of apical constriction, the diversity of roles that apical constriction plays in development, and the common themes that emerge from comparing systems.     

The valosin‐containing protein is a novel repressor of cardiomyocyte hypertrophy induced by pressure overload

Hypertension‐induced left ventricular hypertrophy (LVH) is an independent risk factor for heart failure. Regression of LVH has emerged as a major goal in the treatment of hypertensive patients. Here, we tested our hypothesis that the valosin‐containing protein (VCP), an ATPase associate protein, is a novel repressor of cardiomyocyte hypertrophy under the pressure overload stress. Left ventricular hypertrophy (LVH) was determined by echocardiography in 4‐month male spontaneously hypertensive rats (SHRs) vs. age‐matched normotensive Wistar Kyoto (WKY) rats. VCP expression was found to be significantly downregulated in the left ventricle (LV) tissues from SHRs vs. WKY rats. Pressure overload was induced by transverse aortic constriction (TAC) in wild‐type (WT) mice. At the end of 2 weeks, mice with TAC developed significant LVH whereas the cardiac function remained unchanged. A significant reduction of VCP at both the mRNA and protein levels in hypertrophic LV tissue was found in TAC WT mice compared to sham controls. Valosin‐containing protein VCP expression was also observed to be time‐ and dose‐dependently reduced in vitro in isolated neonatal rat cardiomyocytes upon the treatment of angiotensin II. Conversely, transgenic (TG) mice with cardiac‐specific overexpression of VCP showed a significant repression in TAC‐induced LVH vs. litter‐matched WT controls upon 2‐week TAC. TAC‐induced activation of the mechanistic target of rapamycin complex 1 (mTORC1) signaling observed in WT mice LVs was also significantly blunted in VCP TG mice. In conclusion, VCP acts as a novel repressor that is able to prevent cardiomyocyte hypertrophy from pressure overload by modulating the mTORC1 signaling pathway.     

Recent evidence for activity-dependent initiation of sympathetic sprouting and neuropathic pain

Traumatic injury or inflammatory irritation of the peripheral nervous system often leads to persistent pathophysiological pain states. It has been well-documented that, after peripheral nerve injury or inflammation, functional and anatomical alterations sweep over the entire peripheral nervous system including the peripheral nerve endings, the injured or inflamed afferent fibers, the dorsal root ganglion (DRG), and the central afferent terminals in the spinal cord. Among all the changes, ectopic discharge or spontaneous activity of primary sensory neurons is of great clinical interest, as such discharges doubtless contribute to the develop-ment of pathological pain states such as neuropathic pain. Two key sources of abnormal spontaneous activity have been identified following peripheral nerve injury: the injured afferent fibers (neuroma) leading to the DRG, and the DRG somata. The purpose of this review is to provide a global account of the abnormal spontaneous activity in various animal models of pain. Particular attention is focused on the consequence of peripheral nerve injury and localized inflammation. Further, mechanisms involved in the generation of spontaneous activity are also reviewed; evidence of spontaneous activity in contributing to abnormal sympathetic sprouting in the axotomized DRG and to the initiation of neuropathic pain based on new findings from our research group are discussed. An improved understanding of the causes of spontaneous activity and the origins of neuropathic pain should facilitate the development of novel strategies for effective treatment of pathological pain.     

黄芪对左肾静脉狭窄大鼠肾组织TGF-β1和PAI-1表达的影响

目的观察黄芪对左肾静脉狭窄大鼠肾组织胶原含量及促纤维化因子表达的影响,为临床药物治疗左肾静脉受压综合征提供实验依据。方法将大鼠分为3组,假手术组、模型组和黄芪治疗组。采用左肾静脉不全结扎的方法建立大鼠左肾静脉狭窄模型,用黄芪进行干预,于治疗6周后处死动物。取肾组织行羟脯氨酸含量测定,检测TGF-β1和PAI-1mRNA及蛋白的表达水平。结果模型组大鼠左肾组织羟脯氨酸含量较假手术组增多,TGF-β1和PAI-1的表达增加。黄芪治疗可较少羟脯氨酸含量,减少TGF-β1和PAI-1表达。结论左肾静脉狭窄大鼠可出现肾组织纤维化,黄芪可通过减少TGF-β1和PAI-1的表达来减轻肾组织纤维化损伤。     

Fos Protein Expression in Sacral Spinal Cord in Relation to Early Phase of Cauda Equina Syndrome in Dogs

1. The aim of the present study is to map the incipient phase of Fos expression in the sacral spinal cord neuronal pools of multiple cauda equina constrictions canine model.2. Fos-positive neurons were found bilaterally in the lateral portion of superficial dorsal horn layers (Laminae I–III) and along the lateral edge of the dorsal horn accompanied by the lateral collateral pathway, fibers of Lissauer's tract, terminating at the sacral parasympathetic nucleus. Similarly, high Fos expression was detected in the ventral portion of the dorsal sacral commissure and in the dorsomedial portion of the anterior horns at S₁–S₃ segment level. Finally, a clearly expressed Fos-positivity was disclosed bilaterally in the neuropil of the nucleus Y in the anterior horn.3. Data from the present study show that continuous stimulation of the central fibers of sacral dorsal root ganglia neurons, i.e., fibers of sacral primary afferents, unlike those using various stimulations of the peripheral fibres offers an unusual pattern of Fos-like immunoreactivity.