Fusione di impronte: analisi dei problemi di sicurezza e possibili contromisure

In questa tesi si esamineranno alcune possibili vulnerabilità dei sistemi di riconoscimento di impronte digitali e si tenterà di migliorare la loro sicurezza nei confronti di una tipologia specifica di attacco che utilizza impronte digitali "artificiali" per permettere ad un criminale di utilizzare il documento di un complice. È stata infatti recentemente dimostrata la possibilità di inserire in un documento elettronico caratteristiche biometriche che lo rendono utilizzabile da due diverse persone. Questa problematica di sicurezza è alla base dell’attacco che verrà analizzato in questa tesi e per il quale si cercheranno contromisure efficaci.

Zyxin interacts with the SH3 domains of the cytoskeletal proteins LIM-nebulette and Lasp-1

Zyxin is a versatile component of focal adhesions in eukaryotic cells. Here we describe a novel binding partner of zyxin, which we have named LIM-nebulette. LIM-nebulette is an alternative splice variant of the sarcomeric protein nebulette, which, in contrast to nebulette, is expressed in non-muscle cells. It displays a modular structure with an N-terminal LIM domain, three nebulin-like repeats, and a C-terminal SH3 domain and shows high similarity to another cytoskeletal protein, Lasp-1 (LIM and SH3 protein-1). Co-precipitation studies and results obtained with the two-hybrid system demonstrate that LIM-nebulette and Lasp-1 interact specifically with zyxin. Moreover, the SH3 domain from LIM-nebulette is both necessary and sufficient for zyxin binding. The SH3 domains from Lasp-1 and nebulin can also interact with zyxin, but the SH3 domains from more distantly related proteins such as vinexin and sorting nexin 9 do not. On the other hand, the binding site in zyxin is situated at the extreme N terminus as shown by site-directed mutagenesis. LIM-nebulette and Lasp-1 use the same linear binding motif. This motif shows some similarity to a class II binding site but does not contain the classical PXXP sequence. LIM-nebulette reveals a subcellular distribution at focal adhesions similar to Lasp-1. Thus, LIM-nebulette, Lasp-1, and zyxin may play an important role in the organization of focal adhesions.

Single-stranded DNA-binding proteins regulate the abundance of LIM domain and LIM domain-binding proteins.

The LIM domain-binding protein Ldb1 is an essential cofactor of LIM-homeodomain (LIM-HD) and LIM-only (LMO) proteins in development. The stoichiometry of Ldb1, LIM-HD, and LMO proteins is tightly controlled in the cell and is likely a critical determinant of their biological actions. Single-stranded DNA-binding proteins (SSBPs) were recently shown to interact with Ldb1 and are also important in developmental programs. We establish here that two mammalian SSBPs, SSBP2 and SSBP3, contribute to an erythroid DNA-binding complex that contains the transcription factors Tal1 and GATA-1, the LIM domain protein Lmo2, and Ldb1 and binds a bipartite E-box-GATA DNA sequence motif. In addition, SSBP2 was found to augment transcription of the Protein 4.2 (P4.2) gene, a direct target of the E-box-GATA-binding complex, in an Ldb1-dependent manner and to increase endogenous Ldb1 and Lmo2 protein levels, E-box-GATA DNA-binding activity, and P4.2 and beta-globin expression in erythroid progenitors. Finally, SSBP2 was demonstrated to inhibit Ldb1 and Lmo2 interaction with the E3 ubiquitin ligase RLIM, prevent RLIM-mediated Ldb1 ubiquitination, and protect Ldb1 and Lmo2 from proteasomal degradation. These results define a novel biochemical function for SSBPs in regulating the abundance of LIM domain and LIM domain-binding proteins.

Loss of tumor suppressor mir-203 mediates overexpression of LIM and SH3 Protein 1 (LASP1) in high-risk prostate cancer thereby increasing cell proliferation and migration

Several studies have linked overexpression of the LIM and SH3 domain protein 1 (LASP1) to progression of breast, colon, liver, and bladder cancer. However, its expression pattern and role in human prostate cancer (PCa) remained largely undefined. Analysis of published microarray data revealed a significant overexpression of LASP1 in PCa metastases compared to parental primary tumors and normal prostate epithelial cells. Subsequent gene-set enrichment analysis comparing LASP1-high and -low PCa identified an association of LASP1 with genes involved in locomotory behavior and chemokine signaling. These bioinformatic predictions were confirmed in vitro as the inducible short hairpin RNA-mediated LASP1 knockdown impaired migration and proliferation in LNCaP prostate cancer cells. By immunohistochemical staining and semi-quantitative image analysis of whole tissue sections we found an enhanced expression of LASP1 in primary PCa and lymph node metastases over benign prostatic hyperplasia. Strong cytosolic and nuclear LASP1 immunoreactivity correlated with PSA progression. Conversely, qRT-PCR analyses for mir-203, which is a known translational suppressor of LASP1 in matched RNA samples revealed an inverse correlation of LASP1 protein and mir-203 expression. Collectively, our results suggest that loss of mir-203 expression and thus uncontrolled LASP1 overexpression might drive progression of PCa.

Le conseguenze del pensionamento sulle competenze plurilingui di immigrati italiani in Svizzera

La nostra proposta presenta alcuni aspetti e risultati di un progetto dell'Università di Berna che si occupa delle conseguenze del pensionamento sulle competenze plurilingui di immigrati italiani nella Svizzera tedesca. Rifacendoci a De Bot (2007), che ha definito come “language related major life events” i momenti nella vita rilevanti per mutamenti delle competenze linguistiche, ipotizziamo che il pensionamento possa costituire un punto di svolta nella biografia linguistica di migranti (ma non solo) anche se finora mancano gli studi sull’argomento. Nel caso delle persone prese in considerazione il pensionamento rappresenta un momento fondamentale, quasi paragonabile, per le conseguenze che implica, al momento della migrazione. Se quest'ultima è stata, nella maggior parte dei casi, caratterizzata dalla ricerca di lavoro, la nuova fase della vita dopo il pensionamento comporta mutamenti nelle reti sociali e ha conseguenze anche per l'uso delle lingue. Un punto centrale della ricerca è la domanda di come i migranti affrontino questo momento all’interno della situazione diglossica della Svizzera tedesca, in cui lo svizzero tedesco è stato imparato attraverso il contatto strumentale e accanto ad esso si è mantenuta la lingua d'origine (cfr.Berruto 1991). La metodologia applicata consiste in due fasi: nella prima si utilizzano questionari per ottenere informazioni generali sui dati demografici e sulla situazione sociale, e per elicitare autovalutazioni delle competenze linguistiche. Nella seconda si effettuano interviste semiguidate per ottenere informazioni più approfondite sulla vita e sulle biografie linguistiche. Per ottenere dati relativi alle competenze linguistiche, viene inoltre utilizzato un test di competenza dello svizzero tedesco, sviluppato all’interno del progetto sulla base del SOPI (cfr.Kenyon 2000).

Pensionamento e plurilinguismo. Un'indagine qualitativa su immigrati italiani e su svizzeri tedeschi

Che cosa succede con le competenze linguistiche quando una persona va in pensione? Perde delle competenze perché si indebolisce il contatto con la rete sociale del lavoro o acquisisce nuove competenze grazie alla maggiore disponibilità di tempo (frequentando per esempio un corso di lingua)? Partendo da queste domande il presente lavoro indaga la tematica finora poco studiata della percezione di cambiamenti riguardo all’uso e alle competenze delle lingue durante il processo del pensionamento. Dopo aver passato in rassegna il quadro interdisciplinare degli studi incentrati sulla terza età, viene discusso il complesso di fattori che interagiscono nelle dinamiche del pensionamento. Nella seconda parte del lavoro, si presenta invece una serie di indagini empiriche svolte dall’autrice che offrono un primo approccio sociolinguistico ai mutamenti legati a questo importante momento della vita.

Il plurilinguismo in un corso di tedesco per immigrati italiani ultrasettantenni a Berna

In diesem Artikel möchten wir einen Blick in die Sprachenvielfalt eines besonderen Deutschkurses werfen. Es handelt sich dabei um einen Kurs für pensionierte italienische Migrantinnen in Bern. Die Teilnehmerinnen, alle älter als 70 Jahre, mit meist geringer Schulbildung, haben sich dazu entschlossen, nach der Pensionierung die Sprache des Gastlandes zu erlernen oder ihre Kompetenzen zu verbessern. Wie frühere Studien zeigen konnten, hatten viele Immigranten der 60er Jahre in der Schweiz auf Grund der Diglossie (Werlen 2007) Probleme die deutsche Standardsprache zu erlernen oder sie haben keine der Varietäten gelernt weil Zeit, Motivation und Angebot fehlten. Ein weiteres Resultat dieser diglossischen Situation, mit welcher die Migranten konfrontiert sind, ist ihre Sprachkompetenz, welche als Varietätenkontinuum zwischen einem Deutschschweizer Dialekt und der Standardsprache betrachtet werden kann. Daher werden wir anhand einiger Unterrichtssequenztranskriptionen die sprachlichen Varietäten von vier Kursteilnehmerinnen analysieren und die Funktion der verschiedenen Sprachen und Sprachvarietäten innerhalb des Kurses bestimmen.

Analysis of Lim1 LIM domains in mouse development

Transcriptional regulation is fundamental for the precise development of all organisms. Through tight regulation, necessary genes are activated at proper spatial and temporal patterns, while unnecessary genes are repressed. A large family of regulator proteins that have been demonstrated to be involved in various developmental processes by activation and repression of target genes is the homeodomain family of proteins. To date, the function of many of these homeoproteins has been elucidated in diverse species. However, the molecular mechanism underlying the function of these proteins has not been fully understood. In this study, the molecular mechanism of the function of a LIM-homeoprotein, Lim1, was examined. In addition to the homeodomain, Lim1 contains two LIM domains that are highly conserved among species. This high conservation along with data from in vitro studies on Xenopus Lim1 suggests that the LIM domains might be important for the function of Lim1 as a transcriptional regulator. Here, the functional importance of the LIM domains of Lim1 was determined by using a novel gene-targeting strategy in mouse embryonic stem (ES) cells. A cre-loxP system was used in conjunction with the unique genomic organization of Lim1 to obtain four types of mutant ES cell lines that would allow for the in vivo analysis of the function of both the LIM domains of Lim1 together and also singularly. These four mutant Lim1 alleles either contained base-pair changes at the LIM encoding exons that alters zinc-binding amino acids of the LIM domains or contained only exogenous loxP sequences in the first intron of Lim1, which serves as the control allele. These mutations in the LIM domains would presumably abolish the zinc-finger tertiary structure of the domain and thus render the domain non-functional. Mice carrying mutations at both the LIM domains of Lim1, L1L2, die around E10 without anterior head structures anterior to rhombomere 3, identical in phenotype to the Lim1 null mutants in spite of the presence of mutant Lim1 RNA. This result demonstrates that the integrity of both the LIM domains are essential for the function of Lim1. This is further supported by the phenotype of mice carrying mutation at only the second LIM domain of Lim1, L2. The L2 mice although still carrying one intact Lim1 LIM domain, also die in utero. The L2 mice die at varying times, from around E8 to E10 with anterior defects in addition to other axial defects which have yet to be fully characterized. The results of this study so far demonstrates that the integrity of both LIM domains are required for the function of Lim1. ^

Functional studies of a LIM -homeodomain transcription factor lmx1b in murine mid -hindbrain and limb development

This thesis is centered on applying molecular genetics to study pattern formation during animal development. More specifically, this thesis describes the functional studies of a LIM-homeodomain gene called lmx1b during murine embryogenesis. Lmx1b expression is restricted to the mid-hindbrain junction as well as to the dorsal mesenchyme of the limb, suggesting important functions during mid-hindbrain and limb development. To test these possibilities, lmx1b homozygous mutant mice were generated and their limb and CNS phenotypes examined. Lmx1b homozygous mutant mice exhibit a large reduction of mid-hindbrain structures, and that their limbs are symmetrical along the dorsal-ventral axis as the result of a dorsal to ventral transformation. Taken together, these studies define essential functions for lmx1b in mid-hindbrain patteming and in dorsal limb cell fate determination. However, the molecular mechanisms which accounts for these phenotypes are unknown, and whether lmx1b has same or distinctive functions during the mid-hindbrain and limb development is also unclear. ^ Recently, insight into molecular mechanisms of mid-hindbrain patterning and limb development has resulted from the identification of several factors with restricted expression patterns within these regions. These include the secreted factors wnt-1, fgf-8, wnt-7a and the transcription factors pax-2, and en-1. Targeted disruption of any of these genes in mice suggests that these genes might be involved in similar regulatory pathways. Analysis of the expression of these genes in lmx1b mutants demonstrates that lmxlb is not required for the initiation, but is required to maintain their expression at the mid-hindbrain junction. Thus, lmxlb is not required for specifying mid-hindbrain cell fates, rather, it functions to ensure the establishment or maintenance of a proper organizing center at the mid-hindbrain junction. Interestingly, lmxlb functions cell non-autonomously in chimera analysis, which indicates that lmx1b might regulate the expression of secreted factors such as wnt-1 and/or fgf-8 in the organizing center. In contrast, lmx1b functions cell autonomously in the dorsal limb to govern dorsal ventral limb development and its expression is regulated by with wnt-7a and en-1. However, single and double mutant analysis suggest that all three genes have partially overlapping functions as well as independent functions. The results point toward a complicated network of cross-talks among all three limb axes. ^

Estudio sobre la habilidad cognitiva "identificación" en estudiantes de nivel medio

Una de las metas importante de quienes enseñamos ciencias es lograr que nuestros estudiantes puedan argumentar, describir, explicar y justificar los fenómenos naturales que se proponen estudiar. Para ello es necesario fomentar determinadas habilidades cognitivas que favorezcan el proceso para llegar a este objetivo, una de estas habilidades básicas es la de "identificar". La habilidad de identificar conlleva asociada la habilidad de comparar, no se puede identificar un objeto, un concepto, una expresión, como igual o distinto a otro si antes no se comparó con un patrón. El presente trabajo analiza el aspecto conceptual, icónico y formal de esta habilidad, que se manifiesta en diferentes actividades propuestas a estudiantes de una escuela secundaria del conurbano bonaerense. Las mismas abordan contenidos sobre la tabla periódica de elementos y se resolvieron luego de la lectura y discusión de un texto referente al tema. El análisis de los registros se hizo en base a las dimensiones: conceptual, icónica-formal e icónica-desplazamiento. La dimensión conceptual permite poner en juego más efectivamente la habilidad de "identificar" que las dimensiones icónico-formal e icónico desplazamiento. Para los estudiantes es más sencillo hacer una identificación a través de un concepto que con el empleo de iconos o expresiones formales