Search results for "actin"

piRNAclusterDB 2.0: update and expansion of the piRNA cluster database.

2021

Abstract PIWI-interacting RNAs (piRNAs) and their partnering PIWI proteins defend the animal germline against transposable elements and play a crucial role in fertility. Numerous studies in the past have uncovered many additional functions of the piRNA pathway, including gene regulation, anti-viral defense, and somatic transposon repression. Further, comparative analyses across phylogenetic groups showed that the PIWI/piRNA system evolves rapidly and exhibits great evolutionary plasticity. However, the presence of so-called piRNA clusters as the major source of piRNAs is common to nearly all metazoan species. These genomic piRNA-producing loci are highly divergent across taxa and critically…

Structural basis of PETISCO complex assembly during piRNA biogenesis in C. elegans

2021

AbstractPiwi-interacting RNAs (piRNAs) constitute a class of small RNAs that bind PIWI proteins and are essential to repress transposable elements in the animal germline, thereby promoting genome stability and maintaining fertility. C. elegans piRNAs (21U RNAs) are transcribed individually from minigenes as precursors that require 5’ and 3’ processing. This process depends on the PETISCO complex, consisting of four proteins: IFE-3, TOFU-6, PID-3, and ERH-2. We employ biochemical and structural biology approaches to characterize the PETISCO architecture and its interaction with RNA, together with its effector proteins TOST-1 and PID-1. These two proteins define different PETISCO functions: P…

Effects of tri-n-butyltin(IV) chloride on neurulation of Ciona intestinalis (Tunicata, Ascidiacea): an ultrastructural study

2005

This paper reports the cytotoxic effects of tri-n-butyltin (IV) chloride, TBTCl, on the neurulation process of the ascidian Ciona intestinalis. Exposure of the embryos at early neurula stage in 10−5 and 10−7M TBT (IV) chloride solutions for 1–2 h provoked the irreversible arrest of their development. Morphological and ultrastructural observations suggested that most probably there are two principal causes determining the neurulation process block. The first is due to the TBT effects of inhibiting the polymerization and/or degradation of microfilaments and microtubules, proteins that constitute the cytoskeleton. The lack of orientation and extension of both microtubules and microfilaments of…

Actinic Radiation and Photolysis Processes in the Lower Troposphere: Effect of Clouds and Aerosols

2002

Within the German Tropospheric Research Program (TFS) a series of projects were performed focussing on aspects of radiation transfer and the effects of UV-radiation on air chemistry. The individual projects covered laboratory investigations, instrument development for photolysis processes as well as field studies of actinic radiation and comparison to model calculations. One and three-dimensional models were tested against field campaign data. The results confirm the improvement of measurement technology achieved through deployment of new techniques like spectroradiometry that offer a wider range of investigations than was previously attainable using chemical actinometry or fixed wavelength…

Toxicity of 4-chloro-o-cresol to fish. Light microscopy and chemical analysis of the tissue

1979

Direct Activation of Bax by p53 Mediates Mitochondrial Membrane Permeabilization and Apoptosis

2004

The tumor suppressor p53 exerts its anti-neoplastic activity primarily through the induction of apoptosis. We found that cytosolic localization of endogenous wild-type or trans-activation–deficient p53 was necessary and sufficient for apoptosis. p53 directly activated the proapoptotic Bcl-2protein Bax in the absence of other proteins to permeabilize mitochondria and engage the apoptotic program. p53 also released both proapoptotic multidomain proteins and BH3-only proteins [Proapoptotic Bcl-2family proteins that share only the third Bcl-2homology domain (BH3)] that were sequestered by Bcl-xL. The transcription-independent activation of Bax by p53 occurred with similar kinetics and concentra…

LaXp180, a mammalian ActA-binding protein, identified with the yeast two-hybrid system, co-localizes with intracellular Listeria monocytogenes

2001

The Listeria monocytogenes surface protein ActA is an important virulence factor required for listerial intracellular movement by inducing actin polymerization. The only host cell protein known that directly interacts with ActA is the phosphoprotein VASP, which binds to the central proline-rich repeat region of ActA. To identify additional ActA-binding proteins, we applied the yeast two-hybrid system to search for mouse proteins that interact with ActA. A mouse cDNA library was screened for ActA-interacting proteins (AIPs) using ActA from strain L. monocytogenes EGD as bait. Three different AIPs were identified, one of which was identical to the human protein LaXp180 (also called CC1). Bind…

Hygiene and Eating Healthy Habits and Practices in Spanish Families with Children Aged 6 to 14.

2020

During childhood and pre-adolescence, the family environment is key to initiating and consolidating healthy styles in children through a balanced diet and basic hygiene habits. This study analyses hygiene, nutrition and health practices in Spanish families with children between 6 and 14 years of age according to the type of family (nuclear, single-parent or reconstituted) and the quantity, age and gender of the children. A representative Spanish national sample of 1103 Spanish parents, 270 fathers and 833 mothers, with children aged 6 to 14, is analysed. The study is descriptive, using statistical techniques with classic indicators (means, percentages). The results show that nuclear familie…

Induction of rapid and reversible cytokeratin filament network remodeling by inhibition of tyrosine phosphatases

2002

The cytokeratin filament network is intrinsically dynamic, continuously exchanging subunits over its entire surface, while conferring structural stability on epithelial cells. However, it is not known how cytokeratin filaments are remodeled in situations where the network is temporarily and spatially restricted. Using the tyrosine phosphatase inhibitor orthovanadate we observed rapid and reversible restructuring in living cells, which may provide the basis for such dynamics. By examining cells stably expressing fluorescent cytokeratin chimeras, we found that cytokeratin filaments were broken down and then formed into granular aggregates within a few minutes of orthovanadate addition. After …

La punción aspiración con aguja fina (PAAF) en el diagnóstico de actinomicosis cervicofacial: estudio de 15 casos

2004

Objetivos: La actinomicosis es una enfermedad infecciosa muy poco frecuente en nuestros días, a pesar de lo cual, su diagnóstico debe ser tenido en cuenta por el clínico que se enfrenta a una lesión persistente a nivel cervicofacial. Aún tratándose de una enfermedad infecciosa, los cultivos microbiológicos son pocas veces diagnósticos, por lo que el estudio histopatológico y las pruebas de imagen son esenciales. Nuestro interés es exponer nuestra experiencia en el manejo de la actinomicosis de localización cervicofacial, su presentación clínica, evolución y tratamiento, siempre apoyados en la que creemos que es su técnica diagnóstica de elección, la PAAF. Diseño del estudio: A lo largo de 1…