Influence of the AgrC-AgrA Complex on the Response Time of Staphylococcus aureus Quorum Sensing

The Staphylococcus aureus agr quorum-sensing system plays a major role in the transition from the persistent to the virulent phenotype. S. aureus agr type I to IV strains are characterized by mutations in the sensor domain of the histidine kinase AgrC and differences in the sequences of the secreted autoinducing peptides (AIP). Here we demonstrate that interactions between the cytosolic domain of AgrC (AgrC(Cyto)) and the response regulator domain of AgrA (AgrA(RR)) dictate the spontaneity of the cellular response to AIP stimuli. The crystal structure of AgrC(Cyto) provided a basis for a mechanistic model of AgrC-AgrA interactions. This model enabled an analysis of the biochemical and biophysical parameters of AgrC-AgrA interactions in the context of the conformational features of the AgrC-AgrA complex. This analysis revealed distinct sequence and conformational features that determine the affinity, specificity, and kinetics of the phosphotransfer reaction. This step, which governs the response time for transcriptional reengineering triggered by an AIP stimulus, is independent of the agr type and similar for agonist and antagonist stimuli. These experimental data could serve as a basis on which to validate simulations of the quorum-sensing response and for strategies that employ the agr quorum-sensing system to combat biofilm formation in S. aureus infections.

Una questione agra: l'io traduttore in "Una questione privata" e "La vita agra"

La lingua di Una questione privata e de La vita agra, vista come costruzione culturale condizionata dal contesto, sarà l’oggetto di questo lavoro. L’accento sarà messo sulla sua capacità di andare oltre la mera definizione del dizionario e condizionare il lettore, avvicinandolo ai personaggi. In particolare, si studierà la presenza di termini nella loro lingua originale, come mezzo per permettere al lettore di trovarsi sulla stessa lunghezza d’onda dei personaggi e di avere la loro stessa percezione della realtà. Effettivamente, nei due romanzi scelti, le lingue straniere hanno un forte rilievo, che se nell’opera di Fenoglio si nota soprattutto a livello di riferimenti più o meno impliciti alla letteratura inglese, in quella di Bianciardi si coglie come vera e propria presenza di interferenze. In entrambi i casi, questa tendenza è principalmente dovuta all’esistenza di un “io traduttore”, in cui si incontrano l’io dell’autore e l’io del protagonista. Si può affermare, dunque, che l’uso di termini stranieri sia una scelta stilistica consapevole e volontaria dei due scrittori, che tra l’altro erano anche traduttori, proprio come i loro protagonisti.

La Fuente Agría de Puertollano y su entorno hidrogeológico

La célebre Fuente Agria de Puertollano (Ciudad Real) forma parte del conjunto de manantiales ferruginosos y con alto contenido en CO2 que se hayan asociados a la extensa área volcánica del Campo de Calatrava, representando la fase póstuma del volcanismo terciario y cuaternario que afectó a esta zona. Se trata de una surgencia a presión que procede de la descarga bajo los depósitos miocenos del acuífero de cuarcitas de la Sierra de Santa Ana. Se establece así mismo la caracterización hidrogeológica del entorno regional del manantial en base a sondeos realizados exprofeso, y que incluye el subsuelo de una parte de la ciudad de Puertollano y de la Sierra que lo bordea por el norte. Se propone un modelo hidrogeológico para la explicación de este tipo de fuentes de borde de las sierras, el cual supone la captación del flujo profundo del CO2 mediante fallas en la periferia de las masas impermeables por parte de las aguas que circulan por los niveles cuarcíticos paleozoicos más permeables. Finalmente, se historian algunas de las afecciones que ha sufrido dicho manantial a lo largo de los siglos, y que culmina con el establecimiento de un perímetro de protección a alteraciones desde arriba de origen urbano, aunque se llama la atención de otros posibles impactos por parte de túneles profundos

Iniciativa sobre la cuestión agrária nacional, leída en la sesión del 4 de mayo de 1893,

"Edición especial de la Sociedad Mexicana de Geografía y Estadística."

The Oudh law journal : reports of cases decided by (1) the Judicial Committee of the Privy Council on Appeals from Oudh; (2) the Court of the Judicial Commissioner of Oudh; and (3) the Board of Revenue, United Provinces of Agra and Oudh (Concerning Oudh)

Mode of access: Internet.

Narrative of a journey from Caunpoor to the Boorendo pass, in the Himalaya Mountains viâ Gwalior, Agra, Delhi, and Sirhind;

Mode of access: Internet.

List of inscriptions on Christian tombs and tablets of historical interest in the United Provinces of Agra and Oudh,

Cover title: Christian tombs and monuments in the United Provinces.

District Gazetteers of the United Provinces of Agra and Oudh

Mode of access: Internet.

Report on the Administration of the United Provinces [of Agra and Oudh]

Mode of access: Internet.

Some aspects of calcium phosphate chemistry in sugarcane clarification

This paper reviews some aspects of calcium phosphate chemistry since phosphate in juice is an important parameter in all sugar juice clarification systems. It uses basic concepts to try and explain the observed differences in clarification performance obtained with various liming techniques. The paper also examines the current colorimetric method used for the determination of phosphate in sugar juice. In this method, a phosphomolybdate blue complex formed due to the addition of a dye is measured at 660 nm. Unfortunately, at this wavelength there is interference of the colour arising from within the juice and results in the underestimation of the amount of soluble inorganic phosphate content of juice. It is suggested that phosphate analysis be conducted at the higher wavelength of 875 nm where the interference of the juice colour is minimised.