Suppression of citrus canker disease mediated by flagellin perception.

Citrus cancer, caused by strains of Xanthomonas citri (Xc) and Xanthomonas aurantifolii (Xa), is one of the most economically important citrus diseases. Although our understanding of the molecular mechanisms underlying citrus canker development has advanced remarkably in recent years, exactly how citrus plants fight against these pathogens remains largely unclear. Using a Xa pathotype C strain that infects Mexican lime only and sweet oranges as a pathosystem to study the immune response triggered by this bacterium in these hosts, we herein report that the Xa flagellin C protein (XaFliC) acts as a potent defence elicitor in sweet oranges.

Structural dynamics of SARS-CoV-2 nucleocapsid protein induced by RNA binding.

The nucleocapsid (N) protein of the SARS-CoV-2 virus, the causal agent of COVID-19, is a multifunction phosphoprotein that plays critical roles in the virus life cycle, including transcription and packaging of the viral RNA. To play such diverse roles, the N protein has two globular RNA-binding modules, the N- (NTD) and C-terminal (CTD) domains, which are connected by an intrinsically disordered region. Despite the wealth of structural data available for the isolated NTD and CTD, how these domains are arranged in the full-length protein and how the oligomerization of N influences its RNA-binding activity remains largely unclear.

Regulation of tRNA biogenesis in plants and its link to plant growth and response to pathogens.

The field of tRNA biology, encompassing the functional and structural complexity of tRNAs, has fascinated scientists over the years and is continuously growing. Besides their fundamental role in protein translation, new evidence indicates that tRNA-derived molecules also regulate gene expression and protein synthesis in all domains of life. This review highlights some of the recent findings linking tRNA transcription and modification with plant cell growth and response to pathogens.

Crystal Structure and Regulation of the Citrus Pol III Repressor MAF1 by Auxin and Phosphorylation.

MAF1 is the main RNA polymerase (Pol) III repressor that controls cell growth in eukaryotes. The Citrus ortholog, CsMAF1, was shown to restrict cell growth in citrus canker disease but its role in plant development and disease is still unclear. We solved the crystal structure of the globular core of CsMAF1, which reveals additional structural elements compared with the previously available structure of hMAF1, and explored the dynamics of its flexible regions not present in the structure.

Structure and Mechanism of Dimer-Monomer Transition of a Plant Poly(A)-Binding Protein upon RNA Interaction: Insights into Its Poly(A) Tail Assembly.

Poly(A)-binding proteins (PABPs) play crucial roles in mRNA biogenesis, stability, transport and translational control in most eukaryotic cells. Although animal PABPs are well-studied proteins, the biological role, three-dimensional structure and RNA-binding mode of plant PABPs remain largely uncharacterized. Here, we report the structural features and RNA-binding mode of a Citrus sinensis PABP (CsPABPN1).

Landau-Kleffner syndrome: a study of 29 patients.

Purpose: The aim of the study was to retrospectively analyze the electroclinical features, etiology, treatment, and prognosis of 29 patients with Landau-Kleffner syndrome (LKS) with a long-term follow-up.

Methods: Inclusion criteria were a diagnosis of LKS with: (1) acquired aphasia or verbal auditory aphasia; (2) with or without focal seizures, secondarily generalized tonic-clonic seizures, absences, or atonic seizures.

Results: Mean follow-up was 12 years.

Citrus MAF1, a repressor of RNA polymerase III, binds the Xanthomonas citri canker elicitor PthA4 and suppresses citrus canker development.

Transcription activator-like (TAL) effectors from Xanthomonas species pathogens act as transcription factors in plant cells; however, how TAL effectors activate host transcription is unknown. We found previously that TAL effectors of the citrus canker pathogen Xanthomonas citri, known as PthAs, bind the carboxyl-terminal domain of the sweet orange (Citrus sinensis) RNA polymerase II (Pol II) and inhibit the activity of CsCYP, a cyclophilin associated with the carboxyl-terminal domain of the citrus RNA Pol II that functions as a negative regulator of cell growth. Here, we show that PthA4 specifically interacted with the sweet orange MAF1 (CsMAF1) protein, an RNA polymerase III (Pol III) repressor that controls ribosome biogenesis and cell growth in yeast (Saccharomyces cerevisiae) and human.

The TAL effector PthA4 interacts with nuclear factors involved in RNA-dependent processes including a HMG protein that selectively binds poly(U) RNA.

Plant pathogenic bacteria utilize an array of effector proteins to cause disease. Among them, transcriptional activator-like (TAL) effectors are unusual in the sense that they modulate transcription in the host. Although target genes and DNA specificity of TAL effectors have been elucidated, how TAL proteins control host transcription is poorly understood.

Plant pathogenic bacteria utilize biofilm growth-associated repressor (BigR), a novel winged-helix redox switch, to control hydrogen sulfide detoxification under hypoxia.

Winged-helix transcriptional factors play important roles in the control of gene expression in many organisms. In the plant pathogens Xylella fastidiosa and Agrobacterium tumefaciens, the winged-helix protein BigR, a member of the ArsR/SmtB family of metal sensors, regulates transcription of the bigR operon involved in bacterial biofilm growth. Previous studies showed that BigR represses transcription of its own operon through the occupation of the RNA polymerase-binding site; however, the signals that modulate its activity and the biological function of its operon are still poorly understood.

Mesial temporal lobe epilepsy with hippocampal sclerosis: study of 42 children.

Purpose: We present the electroclinical features, treatment, and evolution of patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS).

Material And Methods: We analyzed the charts of forty-two patients who met the diagnostic criteria of MTLE-HS. The mean follow-up after seizure onset was 10.

[Evaluation of executive functions in children].

Objectives: This is a review of the available instruments to evaluate executive functions in children and adolescents.

Development: Executive functions (EF) give support for organization, anticipation, inhibition, working memory, flexibility, control and autoregulation of behavior. EF appear abnormal in several neurological an psychopathological conditions e.

[Instruments for evaluation of memory abilities in children].

Objectives: This is a review of the more relevant instruments to measure memory abilities of children and adolescents. The strengths, limitations and future developments of these instruments are discussed.

Contents: Memory disturbances are present in developing individuals as a consequence of perinatal damage, brain trauma, neuroinfections, epilepsy etc.

Atypical evolution in childhood epilepsy with occipital paroxysms (Panayiotopoulos type).

We report, on two, school-age girls with clinical and electroencephalographic features of early onset childhood epilepsy with occipital paroxysms (CEOP) of the "Panayiotopoulos type" that showed atypical evolution. Neurological examination and brain imaging were normal in both. One child presented at age 2.

Extratemporal epilepsy in children: candidate selection and surgical treatment.

From June 1988 to June 1998, 60 children with extratemporal epilepsies (EE), most of whom were symptomatic, underwent surgery. All patients were studied by means of CT scanning, MRI and scalp EEG. Video-telemetry was used in 40 cases.

[Acquired epileptic aphasia].

Objective: To evaluate clinical and EEG features, as well as treatment and progression in fifteen patients with a diagnosis of acquired epileptic aphasia.

Patients And Methods: The population comprised nine male and six female patients, whose mean age was 14.5 (r = 8.

[Rasmussen syndrome].

Introduction: Rasmussen's encephalitis is a neurological disorder probably of immunological origin, characterized by intractable epilepsy, neurological deterioration and the presence of antibodies against R3 glutamate receptors.

Objective: To present the experience of an Argentinian Paediatric Neurology Service during the past 7 years.

Material And Methods: We analyzed the clinical histories of 12 patients with RS as defined by the diagnostic criteria proposed by Hart et al.

Acquired epileptic aphasia: neuropsychologic follow-up of 12 patients.

A study of specific neuropsychologic, neurolinguistic, and behavioral features of acquired epileptic aphasia or Landau-Kleffner syndrome was conducted in a group of 12 patients followed-up for 2-15 years (mean: 8 yr). Seventy-five percent had exhibited some language disturbance prior to acquired epileptic aphasia. Even when 9 patients had normal electroencephalographic findings in the long-term course of the disease, only 3 achieved normal language.

A subset of V delta 1+ T cells proliferates in response to Epstein-Barr virus-transformed B cell lines in vitro.

It has previously been shown that murine tissue derived T-cells expressing the gamma delta T-cell receptor can respond to autologous (stressed) cells implying the recognition of an autoantigen. Here we report that a large proportion of human synovial tissue and peripheral blood derived V delta 1+ gamma delta T-cell clones proliferate in response to stimulation with autologous and allogeneic EBV-transformed B-lymphoblastoid cell lines (LCL). In contrast, V delta 1- gamma/delta and alpha/beta TCR+ T-cell clones isolated from the same tissue samples did not display proliferation towards the LCL.