Integrating the actin and vimentin cytoskeletons. adhesion-dependent formation of fimbrin-vimentin complexes in macrophages.

Cells adhere to the substratum through specialized structures that are linked to the actin cytoskeleton. Recent studies report that adhesion also involves the intermediate filament (IF) and microtubule cytoskeletons, although their mechanisms of interaction are unknown. Here we report evidence for a novel adhesion-dependent interaction between components of the actin and IF cytoskeletons. In biochemical fractionation experiments, fimbrin and vimentin coprecipitate from detergent extracts of macrophages using vimentin- or fimbrin-specific antisera. Fluorescence microscopy confirms the biochemical association. Both proteins colocalized to podosomes in the earliest stages of cell adhesion and spreading. The complex is also found in filopodia and retraction fibers. After detergent extraction, fimbrin and vimentin staining of podosomes, filopodia, and retraction fibers are lost, confirming that the complex is localized to these structures. A 1:4 stoichiometry of fimbrin binding to vimentin and a low percentage (1%) of the extracted vimentin suggest that fimbrin interacts with a vimentin subunit. A fimbrin-binding site was identified in the NH(2)-terminal domain of vimentin and the vimentin binding site at residues 143-188 in the CH1 domain of fimbrin. Based on these observations, we propose that a fimbrin-vimentin complex may be involved in directing the assembly of the vimentin cytoskeleton at cell adhesion sites.     

Extended Rank Analysis of Covariance as a More Efficient Matched Analysis Considering Trend Information

Classical matched analysis, regarded as analysis of covariance (ANOCOVA) in a broad sense, makes no attempt in modeling and may therefore be inefficient. In this paper, we discuss the relative efficiencies of the ERMP (extended rank and matched‐pair) test (Chen and Quade , 2000) to standard matched methods, and extend it to the case of multivariate covariables X . Taking advantage of trend information between the response Y and the covariables X by ranking after matching, ERMP test achieves better efficiency than a proposed class of weighted matched statistics. When Y is dichotomous, the optimal weighted matched statistic is equivalent to the Mantel‐Haenszel statistic. Example and simulation results also suggest the conclusion.     

Biochemical changes in the equine capsule following prostaglandin-induced pregnancy failure

The equine embryonic capsule, an acellular covering that envelops the conceptus during the second and third weeks of pregnancy, is composed of mucin-like glycoproteins. Its structure is consistent with a dual role during early pregnancy: protection of the conceptus, and communication between the embryo and the mother. Loss of sialic acid from the capsular glycoproteins at day 16 correlates with the time of “fixation,” or loss of conceptus mobility throughout the uterine horns. This study investigated how the structure of the capsule is linked to the maintenance of pregnancy. Six pregnancies, confirmed by ultrasound, were terminated by prostaglandin injection on day 14, prior to the time of embryo fixation. These “defective” conceptuses were collected at day 17, and the structure and molecular properties of their capsules were compared to those of day 17 conceptuses collected from 5 normal pregnancies. Defective capsules were not significantly different from normal capsules in terms of dry weight, amino acid composition, and content of neutral and amino sugars. However, defective capsules failed to show the loss of sialic acid normally occurring around the time of embryo fixation. Analysis of the capsular mucins following trypsin digestion was carried out by radioactive labeling with ³H on sialyl-oligosaccharides and ¹²⁵I on tyrosine residues, followed by fast protein liquid chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Differences in the trypsin fragmentation patterns indicated increased susceptibility of the defective capsules to proteolysis. We conclude that there is a temporal association between desialylation of the equine capsule and embryonic survival, and that failure to desialylate alters the properties of the capsule. Mol. Reprod. Dev. 46:286–295, 1997. © 1997 Wiley-Liss, Inc.     

Interplay between ethylene and nitrogen nutrition: How ethylene orchestrates nitrogen responses in plants

The stress hormone ethylene plays a key role in plant adaptation to adverse environmental conditions.Nitrogen(N) is the most quantitatively required mineral nutrient for plants,and its availability is a major determinant for crop production.Changes in N availability or N forms can alter ethylene biosynthesis and/or signaling.Ethylene serves as an important cellular signal to mediate root system architecture adaptation,N uptake and translocation,ammonium toxicity,anthocyanin accumulation,and prem...     

HuR-positive stress granules: Potential targets for age-related osteoporosis

Aging impairs osteoblast function and bone turnover, resulting in age-related bone degeneration. Stress granules (SGs) are membrane-less organelles that assemble in response to stress via the recruitment of RNA-binding proteins (RBPs), and have emerged as a novel mechanism in age-related diseases. Here, we identified HuR as a bone-related RBP that aggregated into SGs and facilitated osteogenesis during aging. HuR-positive SG formation increased during osteoblast differentiation, and HuR overexpression mitigated the reduction in SG formation observed in senescent osteoblasts. Moreover, HuR positively regulated the mRNA stability and expression of its target β-catenin by binding and recruiting β-catenin into SGs. As a potential therapeutic target, HuR activator apigenin (API) enhanced its expression and thus aided osteoblasts differentiation. API treatment increased HuR nuclear export, enhanced the recruitment of β-catenin into HuR-positive SGs, facilitated β-catenin nuclear translocation, and contributed osteogenesis. Our findings highlight the roles of HuR and its SGs in promoting osteogenesis during skeletal aging and lay the groundwork for novel therapeutic strategies against age-related skeletal disorders.     

Detection of Toxoplasma gondii Infections using Virus-Like Particles Displaying T. gondii ROP4 Antigen

Toxoplasma gondii ME49 infections are typically diagnosed by serological tests. However, serological diagnosis of RH strain-induced toxoplasmosis remains unknown. In order to develop seradiagnosis of above 2 kinds of infections, we generated recombinant virus-like particles (VLPs) displaying the T. gondii rhoptry protein 4 (ROP4) and evaluated their potential in T. gondii ME49 or RH strain infection diagnostics. Mice were orally infected with either the tachyzoites of T. gondii (RH) or cysts of T. gondii (ME49) at various dosages, and sera were collected at regular intervals. ELISA-based serological tests were performed to assess IgG, IgM, and IgA antibody responses against ROP4 VLP antigen and tissue lysate antigen (TLA). Compared to TLA, IgG, IgM, and IgA levels to ROP4 VLP antigen were significantly higher in the sera of T. gondii RH-infected mice 1 and 2 week post-infection (PI). T. gondii-specific IgG antibody was detected at 1, 2, 4, and 8 week PI in the T. gondii ME49-infected mice with infection dose-dependent manner. These results indicated that the ROP4 VLP antigen was highly sensitive antigens detecting T. gondii RH and ME49 antibodies at an early stage.     

Diversification of plant agronomic traits by genome editing of brassinosteroid signaling family genes in rice

Brassinosteroids (BRs) regulate various agronomic traits such as plant height, leaf angle, and grain size in rice (Oryza sativa L.); thus, BR signaling components are promising targets for molecular rational design. However, genetic materials for BR-signaling genes or family members remain limited in rice. Here, by genome editing using clustered regularly interspaced short palindromic repeats (CRSPR)/Cas9 tools, we generated a panel of single, double, triple, or quadruple mutants within three BR signaling gene families, including GSK3/SHAGGY-LIKE KINASE1 (GSK1)–GSK4, BRASSINAZOLE-RESISTANT1 (OsBZR1)–OsBZR4, and protein phosphatases with kelch-like (PPKL)1–PPKL3, under the same background (Zhonghua11, japonica). The high-order mutants were produced by either simultaneously targeting multiple sites on different genes of one family (GSKs and PPKLs) or targeting the overlapping sequences of family members (OsBZRs). The mutants exhibited a diversity of plant height, leaf angle, and grain morphology. Comparison analysis of the phenotypes together with BR sensitivity tests suggested the existence of functional redundancy, differentiation, or dominancy among the members within each family. In addition, we generated a set of transgenic plants overexpressing GSK2, OsBZR1/2, and PPKL2, respectively, in wild-type or activated forms with fusion of different tags, and also verified the protein response to BR application. Collectively, these plants greatly enriched the diversity of important agronomic traits in rice. We propose that editing of BR-related family genes could be a feasible approach for screening of desired plants to meet different requirements. Release of these materials as well as the related information also provides valuable resources for further BR research and utilization.     

Fluorescent carbon dots synthesized by waste wind turbine blade for photocatalytic degradation

Developing novel waste recycling strategies has become a feasible solution to overcome environmental pollution. In this work, a method of using waste wind turbine blade (WTB) as a carbon source to synthesize blue fluorescent carbon dots (B-CDs) by hydrothermal treatment is proposed. B-CDs are spherical and have an average particle size of 5.2 nm. The surface is rich in C–O, C=O, −CH₃, and N–H bond functional groups, containing five elements: C, O, N, Si, and Ca. The optimal emission wavelength of B-CDs is 463 nm, corresponding to an excitation wavelength of 380 nm. Notably, a relatively high quantum yield of 29.9% and a utilization rate of 40% were obtained. In addition, B-CDs can serve as a photocatalyst to degrade methylene blue dye, with a degradation efficiency of 64% under 40-min irradiation conditions. The presence of holes has a significant influence on the degradation process.