Network genealogy of 195-bp satellite DNA supports the superimposed hybridization hypothesis of Trypanosoma cruzi evolutionary pattern

Trypanosoma cruzi is highly diverse genetically and has been partitioned into six discrete typing units (DTUs), recently re-named T. cruzi I-VI. Although T. cruzi reproduces predominantly by binary division, accumulating evidence indicates that particular DTUs are the result of hybridization events. Two major scenarios for the origin of the hybrid lineages have been proposed. It is accepted widely that the most heterozygous TcV and TcVI DTUs are the result of genetic exchange between TcII and TcIII strains. On the other hand, the participation of a TcI parental in the current genome structure of these hybrid strains is a matter of debate. Here, sequences of the T. cruzi-specific 195-bp satellite DNA of TcI, TcII, Tat, TcV, and TcVI strains have been used for inferring network genealogies. The resulting genealogy showed a high degree of reticulation, which is consistent with more than one event of hybridization between the Tc DTUs. The data also strongly suggest that Tat is a hybrid with two distinct sets of satellite sequences, and that genetic exchange between TcI and TcII parentals occurred within the pedigree of the TcV and TcVI DTUs. Although satellite DNAs belong to the fast-evolving portion of eukaryotic genomes, in >100 satellite units of nine T. cruzi strains we found regions that display 100% identity. No DTU-specific consensus motifs were identified, inferring species-wide conservation. (C) 2010 Elsevier B.V. All rights reserved.

First dynamic kinetic resolution of selenium-containing chiral amines catalyzed by palladium (Pd/BaSO(4)) and Candida antartica lipase (CAL-B)

An efficient method for chemoenzymatic dynamic kinetic resolution of selenium-containing chiral amines (organoselenium-1-phenylethanamines) has been developed, leading to the corresponding amides in excellent enantioselectivities and high isolated yields. This one-pot procedure employs two different types of catalysts: Pd on barium sulphate (Pd/BaSO(4)) as racemization catalyst and lipase (CAL-B) as the resolution catalyst. (C) 2009 Elsevier Ltd. All rights reserved.

Genomic organization and transcription analysis of the 195-bp satellite DNA in Trypanosoma cruzi

The 195-bp satellite DNA is the most abundant Trypanosoma cruzi repetitive sequence. Here we show by RNA blotting and RT-PCR that 195 SAT is intensely transcribed. We observed a positive correlation between the level of satellite RNA and the abundance of the satellite copies in the genome of T cruzi strains and that the satellite expression is not developmentally regulated. By analyzing CL Brener individual reads, we estimated that 195 SAT corresponds to approximately 5% of the CL Brener genome. 195 SAT elements were found in only 37 annotated contigs, indicating that a large number of satellite copies were not incorporated into the assembled data. The assembled satellite units are distributed in non-syntenic regions with Trypanosoma brucei and Leishmania major genomes, enriched with surface proteins, retroelements, RHS and hypothetical proteins. Satellite repeats were not observed in annotated subtelomeric regions. We report that 12 satellite sequences are truncated by the retroelement VIPER. (C) 2008 Elsevier B.V. All rights reserved.

Attitudes towards the minority variety Cal�� in the south of Spain : a sociolinguistic study

Cal�� is a variety spoken by the Spanish Cal�� (i.e. the Roma). It belongs to a group of languages referred to as “Para-Romani”, characterized by Romani vocabulary, but largely non-Romani morphology, phonology and syntax, in the case of Cal�� deriving from Spanish. According to previous research carried out – with focus on the vocabulary and the grammar of this variety – Cal�� is on its way to extinction. However, there is an expressed interest in reintroducing a form called “Romanó-Cal��”. Attitudes play an important role in minority language maintenance as well as in order for a revitalization project to be successful. The aim of this study is to measure the attitudes that both Cal�� and non-Cal�� have towards Cal�� and Cal�� speakers, a type of study never carried out in the past. The methods applied are both direct and indirect. In total, 231 informants listened to different recordings of voices acting as either a “Spanish speaking person” or a “Cal�� speaking person”, a technique referred to as ‘matched guise’, answering questions related to the voices on attitude scales. Furthermore, 182 of the informants rated their agreement or disagreement to positive and negative items towards Cal�� and its speakers on a Likert scale. The results of the analysis indicate that the attitudes differ towards Cal�� and Cal�� speakers, depending on the informant’s (a) ethnicity (b) contact with Cal�� as well as with Cal�� speakers, and (c) gender. It is those who – in their own opinion – belong to the ethnic group Cal��, as well as those who claim that they have some contact with the variety and its speakers, who show positive attitudes in both parts of the study. The women also show more positive attitudes than the men. It is also possible to note positive attitudes towards the variety and its speakers among the subjects with a high level of knowledge of Cal�� words, as well as among those with the highest willingness to use Cal��. These observations suggest that a revitalization project of the variety Cal�� has a clear chance of being successful.