The role of the anaphase-promoting complex/cyclosome in plant growth

The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase that plays a major role in the progression of the eukaryotic cell cycle. This unusual protein complex targets key cell cycle regulators, such as mitotic cyclins and securins, for degradation via the 26S proteasome by ubiquitination, triggering the metaphase-to-anaphase transition and exit from mitosis. Because of its essential role in cell cycle regulation, the APC/C has been extensively studied in mammals and yeasts, but relatively less in plants. Evidence shows that, besides its well-known role in cell cycle regulation, the APC/C also has functions beyond the cell cycle. In metazoans, the APC/C has been implicated in cell differentiation, disease control, basic metabolism and neuronal survival. Recent studies also have shed light on specific functions of the APC/C during plant development. Plant APC/C subunits and activators have been reported to play a role in cellular differentiation, vascular development, shoot branching, female and male gametophyte development and embryogenesis. Here, we discuss our current understanding of the APC/C controlling plant growth

AIP1 is a novel Agenet/Tudor domain protein from Arabidopsis that interacts with regulators of DNA replication, transcription and chromatin remodeling

Background: DNA replication and transcription are dynamic processes regulating plant development that are dependent on the chromatin accessibility. Proteins belonging to the Agenet/Tudor domain family are known as histone modification "readers" and classified as chromatin remodeling proteins. Histone modifications and chromatin remodeling have profound effects on gene expression as well as on DNA replication, but how these processes are integrated has not been completely elucidated. It is clear that members of the Agenet/Tudor family are important regulators of development playing roles not well known in plants. Methods: Bioinformatics and phylogenetic analyses of the Agenet/Tudor Family domain in the plant kingdom were carried out with sequences from available complete genomes databases. 3D structure predictions of Agenet/Tudor domains were calculated by I-TASSER server. Protein interactions were tested in two-hybrid, GST pulldown, semi-in vivo pulldown and Tandem Affinity Purification assays. Gene function was studied in a T-DNA insertion GABI-line. Results: In the present work we analyzed the family of Agenet/Tudor domain proteins in the plant kingdom and we mapped the organization of this family throughout plant evolution. Furthermore, we characterized a member from Arabidopsis thaliana named AIP1 that harbors Agenet/Tudor and DUF724 domains. AIP1 interacts with ABAP1, a plant regulator of DNA replication licensing and gene transcription, with a plant histone modification "reader" (LHP1) and with non modified histones. AIP1 is expressed in reproductive tissues and its down-regulation delays flower development timing. Also, expression of ABAP1 and LHP1 target genes were repressed in flower buds of plants with reduced levels of AIP1. Conclusions: AIP1 is a novel Agenet/Tudor domain protein in plants that could act as a link between DNA replication, transcription and chromatin remodeling during flower development

Drought tolerance conferred to sugarcane by association with Gluconacetobacter diazotrophicus: a transcriptomic view of hormone pathways

Sugarcane interacts with particular types of beneficial nitrogen-fixing bacteria that provide fixed-nitrogen and plant growth hormones to host plants, promoting an increase in plant biomass. Other benefits, as enhanced tolerance to abiotic stresses have been reported to some diazotrophs. Here we aim to study the effects of the association between the diazotroph Gluconacetobacter diazotrophicus PAL5 and sugarcane cv. SP70-1143 during water depletion by characterizing differential transcriptome profiles of sugarcane. RNA-seq libraries were generated from roots and shoots of sugarcane plants free of endophytes that were inoculated with G. diazotrophicus and subjected to water depletion for 3 days. A sugarcane reference transcriptome was constructed and used for the identification of differentially expressed transcripts. The differential profile of non-inoculated SP70-1143 suggests that it responds to water deficit stress by the activation of drought-responsive markers and hormone pathways, as ABA and Ethylene. qRT-PCR revealed that root samples had higher levels of G. diazotrophicus 3 days after water deficit, compared to roots of inoculated plants watered normally. With prolonged drought only inoculated plants survived, indicating that SP70-1143 plants colonized with G. diazotrophicus become more tolerant to drought stress than non-inoculated plants. Strengthening this hypothesis, several gene expression responses to drought were inactivated or regulated in an opposite manner, especially in roots, when plants were colonized by the bacteria. The data suggests that colonized roots would not be suffering from stress in the same way as non-inoculated plants. On the other hand, shoots specifically activate ABA-dependent signaling genes, which could act as key elements in the drought resistance conferred by G. diazotrophicus to SP70-1143. This work reports for the first time the involvement of G. diazotrophicus in the promotion of drought-tolerance to sugarcane cv. SP70-1143, and it describes the initial molecular events that may trigger the increased drought tolerance in the host plant

Effect of mesoporous silica under Neisseria meningitidis transformation process: environmental effects under meningococci transformation

<p>Abstract</p> <p>Background</p> <p>This study aimed the use of mesoporous silica under the naturally transformable <it>Neisseria meningitidis</it>, an important pathogen implicated in the genetic horizontal transfer of DNA causing a escape of the principal vaccination measures worldwide by the capsular switching process. This study verified the effects of mesoporous silica under <it>N. meningitidis </it>transformation specifically under the capsular replacement.</p> <p>Methods</p> <p>we used three different mesoporous silica particles to verify their action in <it>N. meningitis </it>transformation frequency.</p> <p>Results</p> <p>we verified the increase in the capsular gene replacement of this bacterium with the three mesoporous silica nanoparticles.</p> <p>Conclusion</p> <p>the mesouporous silica particles were capable of increasing the capsule replacement frequency in <it>N. meningitidis</it>.</p

SUcceSS, SUrgery for Spinal Stenosis: Protocol of a randomised, placebo-controlled trial

© Author(s) (or their employer(s)) 2019. Introduction: Central lumbar spinal stenosis (LSS) is a common cause of pain, reduced function and quality of life in older adults. Current management of LSS includes surgery to decompress the spinal canal and alleviate symptoms. However, evidence supporting surgical decompression derives from unblinded randomised trials with high cross-over rates or cohort studies showing modest benefits. This protocol describes the design of the SUrgery for Spinal Stenosis (SUcceSS) trial-the first randomised placebo-controlled trial of decompressive surgery for symptomatic LSS. Methods and analysis: SUcceSS will be a prospectively registered, randomised placebo-controlled trial of decompressive spinal surgery. 160 eligible participants (80 participants/group) with symptomatic LSS will be randomised to either surgical spinal decompression or placebo surgical intervention. The placebo surgical intervention is identical to surgical decompression in all other ways with the exception of the removal of any bone or ligament. All participants and assessors will be blinded to treatment allocation. Outcomes will be assessed at baseline and at 3, 6, 12 and 24 months. The coprimary outcomes will be function measured with the Oswestry Disability Index and the proportion of participants who have meaningfully improved their walking capacity at 3 months postrandomisation. Secondary outcomes include back pain intensity, lower limb pain intensity, disability, quality of life, anxiety and depression, neurogenic claudication score, perceived recovery, treatment satisfaction, adverse events, reoperation rate and rehospitalisation rate. Those who decline to be randomised will be invited to participate in a parallel observational cohort. Data analysis will be blinded and by intention to treat. A trial-based cost-effectiveness analysis will determine the potential incremental cost per quality-adjusted life year gained. Ethics and dissemination: Ethics approval has been granted by the NSW Health (reference:17/247/POWH/601) and the Monash University (reference: 12371) Human Research Ethics Committees. Dissemination of results will be via journal articles and presentations at national and international conferences

Genomic evolution and complexity of the Anaphase-promoting Complex (APC) in land plants

<p>Abstract</p> <p>Background</p> <p>The orderly progression through mitosis is regulated by the Anaphase-Promoting Complex (APC), a large multiprotein E₃ubiquitin ligase that targets key cell-cycle regulators for destruction by the 26 S proteasome. The APC is composed of at least 11 subunits and associates with additional regulatory activators during mitosis and interphase cycles. Despite extensive research on APC and activator functions in the cell cycle, only a few components have been functionally characterized in plants.</p> <p>Results</p> <p>Here, we describe an in-depth search for APC subunits and activator genes in the Arabidopsis, rice and poplar genomes. Also, searches in other genomes that are not completely sequenced were performed. Phylogenetic analyses indicate that some APC subunits and activator genes have experienced gene duplication events in plants, in contrast to animals. Expression patterns of paralog subunits and activators in rice could indicate that this duplication, rather than complete redundancy, could reflect initial specialization steps. The absence of subunit APC7 from the genome of some green algae species and as well as from early metazoan lineages, could mean that APC7 is not required for APC function in unicellular organisms and it may be a result of duplication of another tetratricopeptide (TPR) subunit. Analyses of TPR evolution suggest that duplications of subunits started from the central domains.</p> <p>Conclusions</p> <p>The increased complexity of the APC gene structure, tied to the diversification of expression paths, suggests that land plants developed sophisticated mechanisms of APC regulation to cope with the sedentary life style and its associated environmental exposures.</p

Intracerebral infection with dengue-3 virus induces meningoencephalitis and behavioral changes that precede lethality in mice

<p>Abstract</p> <p>Background</p> <p>Dengue, one of the most important arboviral diseases of humans, may cause severe systemic disease. Although dengue virus (DENV) has been considered to be a non-neurotropic virus, dengue infection has been associated recently with a series of neurological syndromes, including encephalitis. In this work, we evaluated behavioral changes and inflammatory parameters in C57BL/6 mice infected with non-adapted dengue virus 3 (DENV-3) genotype I.</p> <p>Methods</p> <p>C57BL/6 mice received 4 × 10³PFU of DENV-3 by an intracranial route. We evaluated the trafficking of leukocytes in brain microvasculature using intravital microscopy, and evaluated chemokine and cytokine profiling by an ELISA test at 3 and 6 days post infection (p.i.). Furthermore, we determined myeloperoxidase activity and immune cell populations, and also performed histopathological analysis and immunostaining for the virus in brain tissue.</p> <p>Results</p> <p>All animals developed signs of encephalitis and died by day 8 p.i. Motor behavior and muscle tone and strength parameters declined at day 7 p.i. We observed increased leukocyte rolling and adhesion in brain microvasculature of infected mice at days 3 and 6 p.i. The infection was followed by significant increases in IFN-γ, TNF-α, CCL2, CCL5, CXCL1, and CXCL2. Histological analysis showed evidence of meningoencephalitis and reactive gliosis. Increased numbers of neutrophils, CD4⁺and CD8⁺T cells were detected in brain of infected animals, notably at day 6 p.i. Cells immunoreactive for anti-NS-3 were visualized throughout the brain.</p> <p>Conclusion</p> <p>Intracerebral infection with non-adapted DENV-3 induces encephalitis and behavioral changes that precede lethality in mice.</p

Classical integrability and quantum aspects of the AdS(3) x S(3) x S(3) x S(1) superstring

In this paper we continue the investigation of aspects of integrability of the type IIA AdS(3) x S(3) x S(3) x S(1) and AdS(3) x S(3) x T(4) superstrings. By constructing a one parameter family of flat connections we prove that the Green-Schwarz string is classically integrable, at least to quadratic order in fermions, without fixing the kappa-symmetry. We then compare the quantum dispersion relation, fixed by integrability up to an unknown interpolating function h(lambda), to explicit one-loop calculations on the string worldsheet. For AdS(3) x S(3) x S(3) x S(1) the spectrum contains heavy, as well as light and massless modes, and we find that the one-loop contribution differs depending on how we treat these modes showing that similar regularization ambiguities as appeared in AdS(4)/CFT(3) occur also here.Comment: 29 pages; v2: updated references and acknowledgmen