Tetrahymena Metallothioneins Fall into Two Discrete Subfamilies

BACKGROUND: Metallothioneins are ubiquitous small, cysteine-rich, multifunctional proteins which can bind heavy metals. METHODOLOGY/PRINCIPAL FINDINGS: We report the results of phylogenetic and gene expression analyses that include two new Tetrahymena thermophila metallothionein genes (MTT3 and MTT5). Sequence alignments of all known Tetrahymena metallothioneins have allowed us to rationalize the structure of these proteins. We now formally subdivide the known metallothioneins from the ciliate genus Tetrahymena into two well defined subfamilies, 7a and 7b, based on phylogenetic analysis, on the pattern of clustering of Cys residues, and on the pattern of inducibility by the heavy metals Cd and Cu. Sequence alignment also reveals a remarkably regular, conserved and hierarchical modular structure of all five subfamily 7a MTs, which include MTT3 and MTT5. The former has three modules, while the latter has only two. Induction levels of the three T. thermophila genes were determined using quantitative real time RT-PCR. Various stressors (including heavy metals) brought about dramatically different fold-inductions for each gene; MTT5 showed the highest fold-induction. Conserved DNA motifs with potential regulatory significance were identified, in an unbiased way, upstream of the start codons of subfamily 7a MTs. EST evidence for alternative splicing in the 3′ UTR of the MTT5 mRNA with potential regulatory activity is reported. CONCLUSION/SIGNIFICANCE: The small number and remarkably regular structure of Tetrahymena MTs, coupled with the experimental tractability of this model organism for studies of in vivo function, make it an attractive system for the experimental dissection of the roles, structure/function relationships, regulation of gene expression, and adaptive evolution of these proteins, as well as for the development of biotechnological applications for the environmental monitoring of toxic substances

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

Linfoma de Hodgkin em baixa faixa etária: relato de dois casos Hodgkin's lymphoma in young children: two cases report

Relato de dois casos de pacientes do sexo masculino com linfoma de Hodgkin (LH) e idades inferiores a 5 anos apresentando linfonodomegalias com evolução de alguns meses e seguimento em nosso serviço. Os estudos imuno-histopatológicos do tumor confirmaram linfoma de Hodgkin, esclerose nodular e positividade para o vírus Epstein-Barr (EBV) em material tumoral, em ambos os casos. Após período de 13 meses em remissão completa houve recidiva em um dos pacientes, mostrando doença agressiva. A análise laboratorial do tumor mostrou as mesmas características da doença inicial, e mantendo a positividade ao EBV. Uma exposição mais precoce e intensa ao EBV poderia aumentar o risco para formas muito precoces da doença e a inesperada evolução poderia estar ligada à associação do subtipo histológico e positividade ao EBV.The cases of two male under five-year-olds diagnosed with Hodgkin's lymphoma presenting as lymphadenopathy in evolution for some months and treated in our hospital are reported. Immunohistopathological findings of the tumors proved the existence of Hodgkin's lymphoma nodular sclerosis and positive Epstein-Barr virus in tumoral material in both cases. After 13 months of complete remission one of the patients relapsed and presented aggressive disease. Laboratorial analyses of the tumor showed the same characteristics as the initial disease including positive Epstein-Barr virus. Early and intense exposure to Epstein-Barr virus may increase the risk related to the very early development of the disease and the unexpected evolution may be connected to the association of the histological subtype and the positive Epstein-Barr virus