28 research outputs found
Deciphering the Translation Initiation Factor 5A Modification Pathway in Halophilic Archaea
Translation initiation factor 5A (IF5A) is essential and highly conserved in Eukarya (eIF5A) and Archaea (aIF5A). The activity of IF5A requires hypusine, a posttranslational modification synthesized in Eukarya from the polyamine precursor spermidine. Intracellular polyamine analyses revealed that agmatine and cadaverine were the main polyamines produced in Haloferax volcanii in minimal medium, raising the question of how hypusine is synthesized in this halophilic Archaea. Metabolic reconstruction led to a tentative picture of polyamine metabolism and aIF5A modification in Hfx. volcanii that was experimentally tested. Analysis of aIF5A from Hfx. volcanii by LC-MS/MS revealed it was exclusively deoxyhypusinylated. Genetic studies confirmed the role of the predicted arginine decarboxylase gene (HVO 1958) in agmatine synthesis. The agmatinase-like gene (HVO 2299) was found to be essential, consistent with a role in aIF5A modification predicted by physical clustering evidence. Recombinant deoxyhypusine synthase (DHS) fromS. cerevisiae was shown to transfer 4-aminobutyl moiety from spermidine to aIF5A from Hfx. volcanii in vitro. However, at least under conditions tested, this transfer was not observed with the Hfx. volcanii DHS. Furthermore, the growth of Hfx. volcanii was not inhibited by the classical DHS inhibitor GC7. We propose a model of deoxyhypusine synthesis in Hfx. volcanii that differs from the canonical eukaryotic pathway, paving the way for further studies
The Elusive Third Subunit IIa of the Bacterial B-Type Oxidases: The Enzyme from the Hyperthermophile Aquifex aeolicus
The reduction of molecular oxygen to water is catalyzed by complicated membrane-bound metallo-enzymes containing variable numbers of subunits, called cytochrome c oxidases or quinol oxidases. We previously described the cytochrome c oxidase II from the hyperthermophilic bacterium Aquifex aeolicus as a ba3-type two-subunit (subunits I and II) enzyme and showed that it is included in a supercomplex involved in the sulfide-oxygen respiration pathway. It belongs to the B-family of the heme-copper oxidases, enzymes that are far less studied than the ones from family A. Here, we describe the presence in this enzyme of an additional transmembrane helix âsubunit IIaâ, which is composed of 41 amino acid residues with a measured molecular mass of 5105 Da. Moreover, we show that subunit II, as expected, is in fact longer than the originally annotated protein (from the genome) and contains a transmembrane domain. Using Aquifex aeolicus genomic sequence analyses, N-terminal sequencing, peptide mass fingerprinting and mass spectrometry analysis on entire subunits, we conclude that the B-type enzyme from this bacterium is a three-subunit complex. It is composed of subunit I (encoded by coxA2) of 59000 Da, subunit II (encoded by coxB2) of 16700 Da and subunit IIa which contain 12, 1 and 1 transmembrane helices respectively. A structural model indicates that the structural organization of the complex strongly resembles that of the ba3 cytochrome c oxidase from the bacterium Thermus thermophilus, the IIa helical subunit being structurally the lacking N-terminal transmembrane helix of subunit II present in the A-type oxidases. Analysis of the genomic context of genes encoding oxidases indicates that this third subunit is present in many of the bacterial oxidases from B-family, enzymes that have been described as two-subunit complexes
Attachment disorganisation and borderline patientsâ metacognitive responses to therapistsâ expressed understanding of their states of mind: A pilot study
This study explores the relationship between psychotherapistsâ validation interventions and patientsâ metacognitive responses at the beginning of treatment of borderline personality disorder (BPD). A model of BPD based on disorganized attachment provides the hypothesis that, before patientsâ internal working model of attachment has been corrected within the therapeutic relationship, therapist interventions that are likely to activate patientsâ attachment system are also likely to induce temporary disorganization of patientsâ metacognitive functions. Any validation intervention implies that therapists openly display an understanding and accepting attitude when they comment on patientsâ reported experiences and is,
therefore, likely to activate the patientsâ attachment system. Linehanâs (1993) manual of dialecticbehavioral therapy (DBT) was used as a guideline to assess validation interventions adopted by therapists. The transcripts of the second individual session in the psychotherapy of 19 consecutive patients were analyzed. Checklists based on the DBT manual were used to identify therapistsâ validating, supportive, and neutral interventions. The Metacognitive Assessment Scale was used to assess changes in specific aspects of patientsâ metacognitive processes during therapeutic dialogues. Following validation interventions, patientsâ responses revealed significantly higher rates of temporary metacognitive failure in comparison to the responses solicited by neutral intervention
La validazione dell'AIMIT
La teoria multi-motivazionale dei Sistemi Interpersonali costituisce la cornice di riferimento dello studio presentato, quale prima fase di validazione dell'AIMIT. I risultati forniscono una prima evidenza empirica dell'affidabilitĂ di tale metodo di studio dei SMI e riconfermano l'importanza della ricerca sulla motivazione interpersonale e sull'intersoggetivitĂ nella prospettiva cognitivo-evoluzionista
Assessment of interpersonal motivation in transcripts (aimit): an inter- and intra-rater reliability study of a new method of detection of interpersonal motivational systems in psychotherapy
Assessing Interpersonal Motivations in Transcripts (AIMIT) is a coding system aiming to systematically detect the activity of interpersonal motivational systems (IMS) in the therapeutic dialogue. An inter- and intra-rater reliability study has been conducted. Sixteen video-recorded psychotherapy sessions were selected and transcribed according to the AIMIT criteria. Sessions relate to 16 patients with
an Axis II diagnosis, with a mean Global Assessment of Functioning of 51. For the intra-rater reliability
evaluation, fi ve sessions have been selected and assigned to fi ve independent coders who where asked
to make a fi rst evaluation, and then a second independent one 14 days later. For the inter-rater reliability
study, the sessions coded by the therapist-coder were jointly revised with another coder and finally classified as gold standard. The 16 standard sessions were sent to other evaluators for the independent coding. The agreement (ĂȘ) was estimated according to the following parameters for each coding unit: evaluation units supported by the âcodableâ activation of one or more IMS; motivational interaction
with reference to the ongoing relation between patient and therapist; an interaction between the patient and another person reported/narrated by the patient; detection of specifi c IMS: attachment (At), caregiving (CG), rank (Ra, sexuality (Se), peer cooperation (PC); and transitions from one IMS to another were also scored. The intra-rater agreement was evaluated through the parameters âcodâ, âAtâ, âCGâ, âRaâ, âSeâ and âPCâ described above. A total of 2443 coding units were analysed. For the nine parameters on which the agreement was calculated, eight [âcoded (Cod)â, âongoing relation (Rel)â, ânarrated relation
(Nar)â, âAtâ, âCGâ, âRaâ, âSeâ and âPCâ] have ĂȘ values comprised between 0.62 (CG) and 0.81 (Cod) and were therefore satisfactory. The scoring of âtransitionsâ showed agreement values slightly below desired
cut-off (0.56). Intra-rater reliability was very good (ĂȘ values for Cod = 0.90; ĂȘ for all IMS = 0.78). Data seem to support the validity of the AIMIT method in terms of reliability, and encourage to further implementation of the AIMIT approac
Il sistema cooperativo-paritetico nell'AIMIT e alleanza terapeutica: studio preliminare sulla validitĂ dei costrutti
La nascita dell' AIMIT (2008, in stampa) come strumento di analisi
della motivazione interpersonale nei trascritti, apre nuove possi-
bilitĂ nell'analisi di aspetti connessi allo studio dei determinanti
della qualitĂ della relazione terapeutica. In questo lavoro preli-
minare, viene proposto un affiancamento dei concetti di Sistema
Motivazionale lnterpersonale (SMI) Cooperativo- Paritetico, cosĂŹ
come descritto nel manuale AIMIT e di Alleanza Terapeutiea
Psychopharmacological treatment in borderline personality disorder: A pilot observational study in a real-world setting
Psychotherapy is the cornerstone of treatment for borderline personality disorder (BPD) while pharmacotherapy should be considered only as an adjunctive intervention. In clinical practice, however, most of BPD patients only receive medication. The aim of the study is to first describe pharmacological treatment in BPD patients in Italy and secondly to evaluate if comorbidity or illness severity are associated with the prescription of different class compounds. Data on pharmacological treatment and clinical evaluation of 75 BPD patients were collected in 5 clinical settings. The association between comorbidity and medication was assessed. Moreover, we evaluated the association between pharmacotherapy and severity, defined by a cluster analysis aimed at detecting different groups of patients. Most of the participants (82.7%) were characterized by polypharmacy, with a mean of 2.4 medications per person. Interestingly, the prescription didn't seem to depend on/be based on the severity of the disorder and was only partially determined by the presence of comorbidity. In conclusion, our findings are similar to what described in other clinical studies, supporting the idea that medication management for BPD is only partially coherent with international guidelines. This pilot study confirms the need for more rigorous studies to gain greater understanding of this topic and diminish the gap between guidelines and the real clinical world