Genome-scale modeling of the protein secretory machinery in yeast

The protein secretory machinery in Eukarya is involved in post-translational modification (PTMs) and sorting of the secretory and many transmembrane proteins. While the secretory machinery has been well-studied using classic reductionist approaches, a holistic view of its complex nature is lacking. Here, we present the first genome-scale model for the yeast secretory machinery which captures the knowledge generated through more than 50 years of research. The model is based on the concept of a Protein Specific Information Matrix (PSIM: characterized by seven PTMs features). An algorithm was developed which mimics secretory machinery and assigns each secretory protein to a particular secretory class that determines the set of PTMs and transport steps specific to each protein. Protein abundances were integrated with the model in order to gain system level estimation of the metabolic demands associated with the processing of each specific protein as well as a quantitative estimation of the activity of each component of the secretory machinery

Análises microbiológicas de alicates ortodônticos

OBJETIVO: avaliar a contaminação bacteriana presente na ponta ativa de alicates ortodônticos utilizados no meio acadêmico. MÉTODOS: selecionou-se 34 alicates, 17 do modelo 347 e 17 do modelo 139. O grupo controle foi composto por 3 alicates de cada modelo, previamente autoclavados. Os alicates do grupo experimental, após o uso, foram imersos em 10ml do meio de cultura líquido Brain-Heart Infusion (BHI) por 2 minutos, seguido de cultivo a 37°C (24 a 48h) e semeadura (duplicata) em diferentes meios de cultura sólidos �� base de ágar, para detecção e identificação de agentes microbianos. RESULTADOS: as análises microbiológicas revelaram contaminação em ambos os tipos de alicates ortodônticos. Observaram-se variadas formas bacterianas, predominando estafilococos e cocos isolados gram-positivos. Os alicates removedores de anéis apresentaram maiores índices de contaminação, com médias entre 2,83 x 10(9) e 6,25 x 10(9) UFC/ml, variando de acordo com o tipo de meio de cultura. Os alicates 139 também continham bactérias da microbiota bucal, com variações entre 1,33 x 10(8) e 6,93 x 10(9) UFC/ml, sendo que a maior média obtida refere-se ao meio de cultura próprio para desenvolvimento de estafilococos, indicando, em certos casos, presença da espécie Staphylococcus aureus, microrganismos que não fazem parte da microbiota bucal normal, sendo comumente encontrados na cavidade nasal e superfícies epiteliais das mãos. CONCLUSÃO: constatou-se que os alicates ortodônticos apresentam-se contaminados, como qualquer outro instrumental odontológico, após serem empregados em atendimentos clínicos. Em razão disso, há necessidade de submetê-los previamente aos procedimentos de esterilização após cada utilização em pacientes.OBJECTIVE: To evaluate bacterial contamination in the active tip of orthodontic pliers used in an academic setting. METHODS: Thirty-four pliers were selected: 17 debonding pliers and 17 model 139 pliers. The control group was composed of 3 previously autoclaved pliers of each model. After use, the pliers in the experimental group were immersed in 10 ml of brain-heart infusion (BHI) culture medium for 2 minutes, incubated at 37º C for 24 to 48 h and seeded in duplicates in different agar-based solid culture media to detect and identify microbial agents. RESULTS: Microbiological analyses revealed that there was contamination in both types of orthodontic pliers. Several bacteria were detected, predominantly staphylococcus and isolated Gram-positive (G+) cocci. The debonding pliers had a greater contamination rate and mean values of 2.83 x 10(9) and 6.25 x 10(9) CFU/ml, with variations according to the type of culture medium. The 139 pliers also had all types of bacteria from the oral microbiota at values that ranged from 1.33 x 10(8) to 6.93 x 10(9) CFU/ml. The highest mean value was found in the medium to grow staphylococci, which confirmed, in certain cases, the presence of Staphylococcus aureus, which are not part of the normal oral microbiota but are usually found in the nasal cavity and on the skin of the hands. CONCLUSION: Orthodontic pliers were contaminated as any other dental instrument after use in clinical situations. Therefore, they should undergo sterilization after each use in patients

Pam16 has an essential role in the mitochondrial protein import motor

Mitochondrial preproteins destined for the matrix are translocated by two channel-forming transport machineries, the translocase of the outer membrane and the presequence translocase of the inner membrane. The presequence translocase-associated protein import motor (PAM) contains four essential subunits: the matrix heat shock protein 70 (mtHsp70) and its three cochaperones Mge1, Tim44 and Pam18. Here we report that the PAM contains a fifth essential subunit, Pam16 ( encoded by Saccharomyces cerevisiae YJL104W), which is selectively required for preprotein translocation into the matrix, but not for protein insertion into the inner membrane. Pam16 interacts with Pam18 and is needed for the association of Pam18 with the presequence translocase and for formation of a mtHsp70 Tim44 complex. Thus, Pam16 is a newly identified type of motor subunit and is required to promote a functional PAM reaction cycle, thereby driving preprotein import into the matrix