Chromatin reorganization and endogenous auxin/cytokinin dynamic activity during somatic embryogenesis of cultured cotton cell

We conducted a systematic assessment and comparative study on the biochemical and cellular characteristics of cultured cotton cells during the entire process of somatic embryogenesis (SE). All staged cultures were widely investigated in this assay. Cell and tissue ectogenesis manipulation combined with flow cytometry (FCM) was employed to cellular study during the whole totipotency process of dedifferentiation and redifferentiation. We identified two phases of chromatin decondensation during the dedifferentiation and redifferentiation. At the same time, sharp increase in the ratio of indoleacetic acid (IAA), isopentenyladenosine group (iPAs) at the same stage of cell dedifferentiation and redifferentiation process serve as distinct biochemical maker of dedifferentiation and SE initiation with the unique feature. Our results suggest the two phases of chromatin reorganization associated with endogenous auxin/cytokinin dynamic activity may underlie dedifferentiation and redifferentiation during the entire SE process in cotton.     

Expression of CD80/86 on B cells is essential for autoreactive T cell activation and the development of arthritis

Depletion of B cells in rheumatoid arthritis is therapeutically efficacious. Yet, the mechanism by which B cells participate in the inflammatory process is unclear. We previously demonstrated that Ag-specific B cells have two important functions in the development of arthritis in a murine model of rheumatoid arthritis, proteoglycan (PG)-induced arthritis (PGIA). PG-specific B cells function as autoantibody-producing cells and as APCs that activate PG-specific T cells. Moreover, the costimulatory molecule CD86 is up-regulated on PG-specific B cells in response to stimulation with PG. To address the requirement for CD80/CD86 expression on B cells in the development of PGIA, we generated mixed bone marrow chimeras in which CD80/CD86 is specifically deleted on B cells and not on other APC populations. Chimeras with a specific deficiency in CD80/CD86 expression on B cells are resistant to the induction of PGIA. The concentration of PG-specific autoantibody is similar in mice sufficient or deficient for CD80/86-expressing B cells, which indicates that resistance to PGIA is not due to the suppression of PG-specific autoantibody production. CD80/86-deficient B cells failed to effectively activate PG-specific autoreactive T cells as indicated by the failure of T cells from PG-immunized CD80/86-deficient B cell chimeras to transfer arthritis into SCID mice. In vitro secondary recall responses to PG are also dependent on CD80/86-expressing B cells. These results demonstrate that a CD80/86:CD28 costimulatory interaction between B cells and T cells is required for autoreactive T cell activation and the induction of arthritis but not for B cell autoantibody production.     

Source apportionment and health risk quantification for heavy metal sources in soils near aluminum-plastic manufacturing facilities in northeast China

Abstract

Identifying the source effect on heavy metals to human health risk is essential for devising and implementing restoration policies for polluted soils. For this purpose, eight heavy metals (As, Cd, Hg, Cr, Cu, Ni, Pb, and Zn) in soil profile samples (0–10, 10–20, 20–30, and 30–40?cm) collected in the area around aluminum-plastic manufacturing facilities (APMF) were determined. An absolute principal component score multiple linear regression (APCS-MLR) model supported by a health risk assessment (HRA) model was developed to determine the source apportionment of soil heavy metals and contribution rate of pollution sources to human health risk. Results showed significant accumulations of eight metals in the topsoil (0–20?cm), parent material, transportation, APMF, and agricultural practices were the four major contributing sources for heavy metals in soils, with average contribution percentages of 21.69%, 24.99%, 29.60%, and 14.25%, respectively. Carcinogenic risk factors for adults (1.23E-04) and children (1.32E-04) were found to be above the acceptable level (1E-06 to 1E-04). The health risk quantification results indicated that parent material, APMF, transportation, agricultural practices, and unidentified factors accounted for 55.76%, 14.48%, 12.09%, 10.13%, and 7.54% of the carcinogenic risk for children and adults. The adverse impacts of Cd, Zn, and Pb accumulations in soil coming from APMF activities were significant and need to receive more attention.     

Mucosal and systemic immunity in mice after intranasal immunization with recombinant Lactococcus lactis expressing ORF6 of PRRSV

The purpose of the study was to construct mucosal vaccine of a recombinant Lactococcus lactis expressing PRRSV ORF6 gene and evaluate mucosal and systemic immune response against PRRSV in mice after intranasal immunization. The result show that the vaccine can stimulate mice to produce specific IgG in serum and remarkable special s-IgA in lung lavage fluid, at the same time, the contents of cytokines IL-2 and IFN-γ of the experimental group were significant higher than those of the control group (P < 0.01), however, the contents of cytokines IL-4 was not different to the all groups. In summary, the constructed mucosal vaccine can significantly induce mucosal immune, humoral immunity and cellular immunity involved Th1 type cytokines, which will lay a theoretical foundation on immune mechanism and new efficient vaccines for PRRSV.     

Cofilin-linked changes in actin filament flexibility promote severing

The actin regulatory protein, cofilin, increases the bending and twisting elasticity of actin filaments and severs them. It has been proposed that filaments partially decorated with cofilin accumulate stress from thermally driven shape fluctuations at bare (stiff) and decorated (compliant) boundaries, thereby promoting severing. This mechanics-based severing model predicts that changes in actin filament compliance due to cofilin binding affect severing activity. Here, we test this prediction by evaluating how the severing activities of vertebrate and yeast cofilactin scale with the flexural rigidities determined from analysis of shape fluctuations. Yeast actin filaments are more compliant in bending than vertebrate actin filaments. Severing activities of cofilactin isoforms correlate with changes in filament flexibility. Vertebrate cofilin binds but does not increase the yeast actin filament flexibility, and does not sever them. Imaging of filament thermal fluctuations reveals that severing events are associated with local bending and fragmentation when deformations attain a critical angle. The critical severing angle at boundaries between bare and cofilin-decorated segments is smaller than in bare or fully decorated filaments. These measurements support a cofilin-severing mechanism in which mechanical asymmetry promotes local stress accumulation and fragmentation at boundaries of bare and cofilin-decorated segments, analogous to failure of some nonprotein materials.     

Influence of phytochemicals on the biocompatibility of inorganic nanoparticles: a state-of-the-art review

Inorganic nanoparticles (NPs) are among the most produced NPs that could be used in consumer products and as healthcare materials, however, the intrinsic toxicity particularly through the mechanism associated oxidative stress raises the health concern about inorganic NP exposure. Phytochemicals are bioactive metabolites derived from plants as well as non-pathogenic microorganisms living within plants and have been shown to be beneficial to human health with their anti-aging, anti-cancer, anti-inflammation and anti-oxidant properties. In the present review, the influence of on the biocompatibility of inorganic NPs was discussed. It has been shown that phytochemicals could be used as bio-friendly capping agents for green synthesis of inorganic NPs, and phytochemical coated inorganic NPs were remarkable stable and biocompatible with high therapeutic efficiency. Meanwhile, the presence of phytochemicals was also able to reduce the side effects and enhance the therapeutic abilities of inorganic NPs, which is likely attributed to the anti-oxidative properties of phytochemicals. Thus, using phytochemicals could be a promising and plausible way to reduce side effects and increase the biocompatibility of inorganic NPs for biomedical applications.