Structural aspects of RimP binding on small ribosomal subunit from Staphylococcus aureus.

Ribosome biogenesis is an energy-intense multistep process where even minimal defects can cause severe phenotypes up to cell death. Ribosome assembly is facilitated by biogenesis factors such as ribosome assembly factors. These proteins facilitate the interaction of ribosomal proteins with rRNA and correct rRNA folding. One of these maturation factors is RimP which is required for efficient 16S rRNA processing and 30S ribosomal subunit assembly. Here, we describe the binding mode of Staphylococcus aureus RimP to the small ribosomal subunit and present a 4.2 Å resolution cryo-EM reconstruction of the 30S-RimP complex. Together with the solution structure of RimP solved by NMR spectroscopy and RimP-uS12 complex analysis by EPR, DEER, and SAXS approaches, we show the specificity of RimP binding to the 30S subunit from S. aureus. We believe the results presented in this work will contribute to the understanding of the RimP role in the ribosome assembly mechanism.

Backbone and side chain NMR assignments for the ribosome maturation factor P (RimP) from Staphylococcus aureus.

The ribosomal maturation factor (RimP) is a 17.7 kDa protein and is the assembly factor of the 30S subunit. RimP is essential for efficient processing of 16S rRNA and maturation (assembly) of the 30S ribosome. It was suggested that RimP takes part in stabilization of the central pseudoknot at the early stages of the 30S subunit maturation, and this process may occur before the head domain assembly and later stages of the 30S assembly, but the mechanism of this interaction is still not fully understood. Here we report the assignment of the 1H, 13C and 15N chemical shift in the backbone and side chains of RimP from Staphylococcus aureus. Analysis of chemical shifts of the main chain using TALOS + suggests that the RimP contains eight ß-strands and three α-helices with the topology α1-ß1-ß2-α2- ß3- α3- ß4- ß5- ß6- ß7- ß8. Structural studies of RimP and its complex with the ribosome by integrated structural biology approaches (NMR spectroscopy, X-ray diffraction analysis and cryoelectron microscopy) will allow further screening of highly selective inhibitors of the translation of S. aureus.

Protein Assistants of Small Ribosomal Subunit Biogenesis in Bacteria.

Ribosome biogenesis is a fundamental and multistage process. The basic steps of ribosome assembly are the transcription, processing, folding, and modification of rRNA; the translation, folding, and modification of r-proteins; and consecutive binding of ribosomal proteins to rRNAs. Ribosome maturation is facilitated by biogenesis factors that include a broad spectrum of proteins: GTPases, RNA helicases, endonucleases, modification enzymes, molecular chaperones, etc. The ribosome assembly factors assist proper rRNA folding and protein-RNA interactions and may sense the checkpoints during the assembly to ensure correct order of this process. Inactivation of these factors is accompanied by severe growth phenotypes and accumulation of immature ribosomal subunits containing unprocessed rRNA, which reduces overall translation efficiency and causes translational errors. In this review, we focus on the structural and biochemical analysis of the 30S ribosomal subunit assembly factors RbfA, YjeQ (RsgA), Era, KsgA (RsmA), RimJ, RimM, RimP, and Hfq, which take part in the decoding-center folding.

Changes in Right Ventricular Function After Off-Pump Coronary Artery Bypass Grafting.

OBJECTIVE: Right ventricular (RV) dysfunction is associated with poor outcomes after cardiac surgery. The aim of this study was to assess RV systolic and diastolic function in the perioperative period after off-pump coronary artery bypass grafting (OPCAB). DESIGN: Prospective observational study. SETTINGS: Tertiary care hospital. PARTICIPANTS: Thirty adult patients undergoing OPCAB. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Transthoracic echocardiography was performed twice: first preoperatively and second postoperatively, when patients were moved to wards. The following five parameters of RV systolic function were used: tricuspid annular plane systolic excursion (TAPSE), systolic tissue Doppler imaging of lateral tricuspid annulus (S'), fractional area change (FAC), RV myocardial performance index (RIMP), and isovolumic acceleration (IVA). Grading of RV diastolic function (RVDD) was done as per guidelines. Paired t test was used for comparing means and χ2 test was used for categorical and ordinal data. The parameters of RV longitudinal function (TAPSE and S') reduced significantly (preoperative 21.93 ± 2.80 mm and 13.24 ± 2.24 cm/s to postoperative 11.67 ± 1.91 mm and 10.31 ± 1.56 cm/s, respectively, p < 0.001), whereas parameters of RV global function (FAC, RIMP, and IVA) remained preserved (preoperative 46.75 ± 6.80%, 0.34 ± 0.06, and 4.66 ± 0.87 m/s2 to postoperative 46.21 ± 6.44%, 0.36 ± 0.06, and 4.37 ± 0.83 m/s2; p values of 0.76, 0.13, and 0.11, respectively). The median grade of RVDD worsened from normal in the preoperative period to pseudo-normal in the postoperative period (p < 0.001). The changes in both RV systolic and diastolic function were similar in patients with normal and reduced left ventricular systolic function. CONCLUSIONS: RV function can be assessed in perioperative settings with two-dimensional and tissue Doppler imaging. For systolic function assessment, exclusive measurement of longitudinal parameters might be inadequate; use of complementary global parameters like FAC, RIMP, and IVA is essential to complete the RV assessment after OPCAB. RVDD worsened significantly after OPCABG.

Biological activity of quinazoline analogues and molecular modeling of their interactions with G-quadruplexes.

BACKGROUND: Quinazolines 1 to 6, with an aromatic or aryl-vinyl substituent in position 2 are selected with the aim to compare their structures and biological activity. The selection includes a natural alkaloid, schizocommunin, and the synthetic 2-(2'-quinolyl)-3H-quinazolin-4-one, known to interact with guanine-quadruplex dependent enzymes, respectively telomerase and topoisomerase. METHODS: Breast cancer cells of the MDA cell line have been used to study the bioactivity of the tested compounds by the method of Comet Assay and FACS analyses. We model observed effects assuming stacking interactions of studied heterocycles with a naked skeleton of G-quadruplex, consisting of guanine quartet layers and potassium ions. Interaction energies are computed using a dispersion corrected density functional theory method, and an electron-correlated molecular orbital theory method. RESULTS: Selected compounds do not remarkably delay nor change the dynamics of cellular progression through the cell cycle phases, while changing significantly cell morphology. Our computational models quantify structural effects on heterocyclic G4-complex stabilization energies, which directly correlate with observed biological activity. CONCLUSION: Our computational model of G-quadruplexes is an acceptable tool for the study of interaction energies of G-quadruplexes and heterocyclic ligands, predicting, and allowing design of novel structures. GENERAL SIGNIFICANCE: Genotoxicity of quinazolin-4-one analogues on human breast cancer cells is not related to molecular metabolism but rather to their interference with G-quadruplex regulatory mechanisms. Computed stabilization energies of heterocyclic ligand complexes of G-quadruplexes might be useful in the prediction of novel telomerase / helicase, topoisomerase and NA polymerase dependent drugs.

[Risk of incarceration of persons undergoing psychiatric care. A retrospective longitudinal study on the French department of Oise using information from a psychiatric hospital discharge database]. / Le risque d'incarcération des personnes suivies en psychiatrie. Une étude longitudinale rétrospective dans le département français de l'Oise à partir du Recueil d'informations médicalisé en psychiatrie.

INTRODUCTION: Compared to the general population, persons with mental disorders are overrepresented in prison. In a study carried out in Picardy (northern France) in 2017, a quarter of those entering prison had had contact with a psychiatric service prior to their incarceration. Since to our knowledge no work on this subject has been published in France, we conducted a retrospective study, the main objective of which was to propose an estimate measure of incarceration likelihood in people with mental disorders. METHODS: Using data from a psychiatric hospital discharge database (Recueil d'informations médicalisé en psychiatrie, RimP), we searched for patients aged 18 and older who had received psychiatric care (except for those who were incarcerated at baseline) at the Oise psychiatric hospital in 2015-2016 and identified those who had also been registered by the psychiatric care tool (DSP) in liaison with the same hospital. As a marker of incarceration, registration was the event to be investigated. Survival analyses (Kaplan-Meier), first simple and then stratified by age, gender, past history, main diagnosis and intensity of care outside of prison were carried out to calculate likelihood of incarceration. A multivariate Cox model was used in order to identify the factors associated with incarceration. RESULTS: Among the 25,029 patients monitored in the Oise psychiatric hospital in 2015-2016, 126 had experienced incarceration during the 12 months following their inclusion in the study, i.e. an incarceration probability of 0.45% (95 % confidence interval: 0.37-0.55%). The incarcerated patients were younger (36.6 years in average versus 44.7-Pt-test<0.0001), more often male (96.8% versus 43.7% - P<0.0001), and had a more frequent history of detention (11.1% versus 0.6% - P <0.0001) and psychiatric care (20.6% versus 10.1% - P<0.0001) than the general population. The probability of incarceration at 12 months for the population followed in the psychiatry unit was 3.2 times higher than the detention rate of the general population in Oise over the same period. CONCLUSION: Our study confirms the pronouncedly high incarceration rate of people with mental disorders. Scheduled to begin in 2020, coding in the RimP of a single nationwide patient identifier for all the procedures and stays described will allow the generalized measurement by means of the proposed indicator throughout France.

Backbone and sidechain NMR assignments for the ribosome maturation factor RimP from Escherichia coli.

Ribosome biogenesis is an energetically expensive and complex cellular process that involves the coordinated folding of the ribosomal RNA and dozens of ribosomal proteins. It proceeds along multiple parallel pathways and is guided by trans-acting factors called ribosome assembly factors. Although this process has been studied for decades, there are still many open questions regarding the role of the ribosome assembly factors in directing the folding of ribosome biogenesis intermediates. RimP is one of the early acting factors and guides the assembly of the small 30S ribosomal subunit by facilitating the binding of ribosomal proteins uS5 and uS12. Here we report the virtually complete 1H, 15N, and 13C chemical shift assignment of RimP from Escherichia coli. The NMR chemical shift data, deposited in the BMRB data bank under Accession No. 28014, indicates a widely folded protein composed of three alpha helices and eight beta strands.

In vivo infection and In vitro stress survival studies of acid susceptible mutant of Mycobacterium fortuitum.

Background: Ubiquitous presence of Mycobacterium fortuitum and ability to cause infections in human beings, hints toward its integral resistance against environmental and host stress conditions. With an aim to identify genes responsible for adapting in vitro acidic stress of M. fortuitum, in the previous study, TnphoA random mutagenesis identified acid susceptible mutant MT727, with mutation in ribosomal maturation factor encoding gene rimP, to be mutated. The present study was conducted to explore virulent behavior as well as growth behavior under in vitro stress conditions. Methods: Acid susceptible transposon mutant MT727 was injected intravenously in female BALB/c mice and kidney tissue was analyzed for the bacillary load as well as pathological characterization. Cytokine profiling of MT727-infected mice serum was done. MT727 was also subjected to various in vitro stress conditions, including detergent stress, heat stress, and hypoxic stress. The viable count of bacteria under different stress conditions was determined at regular time interval. Results: Mutant MT727 showed slight variation in bacillary load in vivo; however, defective growth behavior under detergent and hypoxic stress was observed when compared to wild type strain. Conclusion: Results conclude probable involvement of rimP gene in survival of M. fortuitum under hypoxic stress and detergent stress conditions.

[Quality of the diagnoses' coding (main or associated diagnoses) in the medico-administrative database for psychiatric care (RIM-P) in 2015 and 2016, France]. / Qualité du codage des diagnostics et motifs de prise en charge (principal et associés) dans le recueil d'informations médicalisé en psychiatrie (RIM-P) en 2015 et 2016, France.

BACKGROUND: Based on the observation of the misuse of ICD-10 to code the diagnoses in the RIM-P (lack of completeness, conformity and diversity), the Technical Agency for information on Hospital Care (ATIH), which provides tools for collecting medical information, conducted two actions in 2016. First, a chapter devoted to the instructions of coding has been written in the methodological guide of production of the RIM-P, second, a variable "type psy" was added to the ICD-10 nomenclature's file framing ICD-10 coding in the RIM-P. The purpose of this study is to describe the quality of diagnosis coding using ICD-10 in the RIM-P in 2015 and 2016. METHODS: The quality of diagnosis coding using ICD-10 in the summaries of activity of the RIM-P national databases was described in 2015 and 2016. The study focused on the completeness, the conformity and the diversity of coding. RESULTS: Between 2015 and 2016, the percentage of summaries without primary diagnosis ("DP") decreased slightly for full-time (5.2% vs. 3.8%), part-time (6.3% vs. 4.9%) inpatient stays and outpatient care (9.9% vs. 8.9%). ICD-10 codes used to code DP or associated diagnosis ("DA"), while prohibited, mainly belong to Chapter V Mental and behavioral disorders. Per year, only one-third of the summaries and one-half of patients had two or more ICD-10 codes reported for inpatient stays (one-fifth of the summaries and one-fourth of the patients for outpatient care). In addition, per year and per facility, the average number of distinct ICD-10 codes used to fill "DP" or "DA" was approximately half as important in part-time hospitalization, as in full-time hospitalization or for outpatient care. Moreover, 90% of the health facilities used<550 distinct ICD-10 codes in full-time inpatient stays,<270 in part-time inpatient stays and<950 for outpatient care to code the "DP" or the "DA". The diversity of ICD-10 codes used was low and similar between 2015 and 2016, especially to describe the socio-economic environment, resistance to treatment or non-compliance. CONCLUSION: This study emphasizes the need for a collective effort to improve the diversity of the diagnoses' coding in the RIM-P.

Ribosomal maturation factor (RimP) is essential for survival of nontuberculous mycobacteria Mycobacterium fortuitum under in vitro acidic stress conditions.

Mycobacterium fortuitum is an important human pathogenic NTM, which resists stress conditions inside macrophages by exploitation of specific genes. TnphoA-based transposon mutagenesis was employed to identify membrane genes responsible for survival of M. fortuitum under such stress conditions. A library of about 450 mutants was constructed after electroporation of vector pRT291 into wild-type M. fortuitum. On the basis of blue color development and alkaline phosphatase assay, 20 mutants were shortlisted to screen for growth and survival under acidic stress at pH 6.5, 5.5, 4.5, and 3.5. Mutant MT727 showed reduced growth and survival under acidic stress. The acid susceptible mutant MT727 was subjected to other in vitro stress conditions prevalent inside macrophages including oxidative, nutrient starvation and nitrosative stress. However, the mutant showed no appreciable difference in growth behavior under oxidative, nutrient starvation and nitrosative stress conditions in comparison to the wild type. Genomic and bioinformatics analysis of MT727 led to identification of putative ribosomal maturation factor RimP of M. fortuitum to be affected by mutagenesis, showing closest homology to M. abscessus RimP. In silico functional interaction of RimP protein using STRING database showed its interaction with proteins of ribosomal assembly and maturation. Results indicate role of rimP gene in survival of M. fortuitum under acidic stress conditions which may be further explored for use as a potential drug target against M. fortuitum and other mycobacterial infections.

The ribosomal maturation factor P from Mycobacterium smegmatis facilitates the ribosomal biogenesis by binding to the small ribosomal protein S12.

The ribosomal maturation factor P (RimP) is a highly conserved protein in bacteria and has been shown to be important in ribosomal assembly in Escherichia coli Because of its central importance in bacterial metabolism, RimP represents a good potential target for drug design to combat human pathogens such as Mycobacterium tuberculosis However, to date, the only RimP structure available is the NMR structure of the ortholog in another bacterial pathogen, Streptococcus pneumoniae Here, we report a 2.2 Å resolution crystal structure of MSMEG_2624, the RimP ortholog in the close M. tuberculosis relative Mycobacterium smegmatis, and using in vitro binding assays, we show that MSMEG_2624 interacts with the small ribosomal protein S12, also known as RpsL. Further analyses revealed that the conserved residues in the linker region between the N- and C-terminal domains of MSMEG_2624 are essential for binding to RpsL. However, neither of the two domains alone was sufficient to form strong interactions with RpsL. More importantly, the linker region was essential for in vivo ribosomal biogenesis. Our study provides critical mechanistic insights into the role of RimP in ribosome biogenesis. We anticipate that the MSMEG_2624 crystal structure has the potential to be used for drug design to manage M. tuberculosis infections.

Chalcogen 'like-like' Interactions Involving Trisulphide and Triselenide Compounds: A Combined CSD and Ab Initio Study.

In this manuscript, we combined a search in the Cambridge Structural Database (CSD) and ab initio calculations (RI-MP2/def2-TZVPD level of theory) to analyze the ability of trisulphide and triselenide moieties to establish chalcogen 'like-like' interactions. A preliminary CSD inspection revealed two predominant structural patterns, depending on the anti or syn conformation adopted by the substituents of the S3/Se3 bridge, leading to bifurcated or double chalcogen bonding interactions, respectively. In order to analyze these two relevant structural motifs we have used a series of S and Se derivatives Ch3X2 (Ch = S and Se and X = H, F, CN, and CF3) which act as both electron donor (using the lone pairs) and acceptor (using the σ-holes) entities. Besides, we have carried out "atoms in molecules" (AIM) and natural bonding orbital (NBO) analyses to further describe and characterize the chalcogen bonding interactions described herein. As far as we know, chalcogen···chalcogen interactions involving trichalconides (S3/Se3) have not been previously described in literature a may be of great importance in the preparation and characterization of new solids based on this subclass of σ-hole bonding.

Substituent Effects in Multivalent Halogen Bonding Complexes: A Combined Theoretical and Crystallographic Study.

In this manuscript, we combined ab initio calculations (RI-MP2/def2-TZVPD level of theory) and a search in the CSD (Cambridge Structural Database) to analyze the influence of aromatic substitution in charge-assisted multivalent halogen bonding complexes. We used a series of benzene substituted iodine derivatives C6H4(IF4)Y (Y = H, NH2, OCH3, F, CN, and CF3) as Lewis acids and used Cl- as electron rich interacting atoms. We have represented the Hammett's plot and observed a good regression coefficient (interaction energies vs. Hammett's σ parameter). Additionally, we demonstrated the direct correlation between the Hammett's σ parameter and the value of molecular electrostatic potential measured at the I atom on the extension of the C-I bond. Furthermore, we have carried out AIM (atoms in molecules) and NBO (natural bonding orbital) analyses to further describe and characterize the interactions described herein. Finally, we have carried out a search in the CSD (Cambridge Structural Database) and found several X-ray structures where these interactions are present, thus giving reliability to the results derived from the calculations.

[Study of algorithms to identify schizophrenia in the SNIIRAM database conducted by the REDSIAM network]. / Étude des algorithmes de repérage de la schizophrénie dans le Sniiram par le réseau REDSIAM.

BACKGROUND: The aim of the REDSIAM network is to foster communication between users of French medico-administrative databases and to validate and promote analysis methods suitable for the data. Within this network, the working group "Mental and behavioral disorders" took an interest in algorithms to identify adult schizophrenia in the SNIIRAM database and inventoried identification criteria for patients with schizophrenia in these databases. METHODS: The methodology was based on interviews with nine experts in schizophrenia concerning the procedures they use to identify patients with schizophrenia disorders in databases. The interviews were based on a questionnaire and conducted by telephone. RESULTS: The synthesis of the interviews showed that the SNIIRAM contains various tables which allow coders to identify patients suffering from schizophrenia: chronic disease status, drugs and hospitalizations. Taken separately, these criteria were not sufficient to recognize patients with schizophrenia, an algorithm should be based on all of them. Apparently, only one-third of people living with schizophrenia benefit from the longstanding disease status. Not all patients are hospitalized, and coding for diagnoses at the hospitalization, notably for short stays in medicine, surgery or obstetrics departments, is not exhaustive. As for treatment with antipsychotics, it is not specific enough as such treatments are also prescribed to patients with bipolar disorders, or even other disorders. It seems appropriate to combine these complementary criteria, while keeping in mind out-patient care (every year 80,000 patients are seen exclusively in an outpatient setting), even if these data are difficult to link with other information. Finally, the experts made three propositions for selection algorithms of patients with schizophrenia. CONCLUSION: Patients with schizophrenia can be relatively accurately identified using SNIIRAM data. Different combinations of the selected criteria must be used depending on the objectives and they must be related to an appropriate length of time.

[Long-term psychiatric hospitalizations]. / Les hospitalisations longues en psychiatrie.

BACKGROUND: Long-term hospitalizations in psychiatry raise the question of desocialisation of the patients and the inherent costs. METHODS: Individual indicators were extracted from a medical administrative database containing full-time psychiatric hospitalizations for the period 2011-2013 of people over 16 years old living in the French region of Nord-Pas-de-Calais. We calculated the proportion of people who had experienced a hospitalization with a duration of 292 days or more during the study period. A bivariate analysis was conducted, then ecological data (level of health-care offer, the deprivation index and the size of the municipalities of residence) were included into a multilevel regression model in order to identify the factors significantly related to variability of long-term hospitalization rates. RESULTS: Among hospitalized individuals in psychiatry, 2.6% had had at least one hospitalization of 292 days or more during the observation period; the number of days in long-term hospitalization represented 22.5% of the total of days of full-time hospitalization in psychiatry. The bivariate analysis revealed that seniority in the psychiatric system was strongly correlated with long hospitalization rates. In the multivariate analysis, the individual indicators the most related to an increased risk of long-term hospitalization were: total lack of autonomy (OR=9.0; 95% CI: 6.7-12.2; P<001); diagnoses of psychological development disorders (OR=9.7; CI95%: 4.5-20.6; P<.001); mental retardation (OR=4.5; CI95%: 2.5-8.2; P<.001): schizophrenia (OR=3.0; CI95%: 1.7-5.2; P<.001); compulsory hospitalization (OR=1.7; CI95%: 1.4-2.1; P<.001); having experienced therapeutic isolation (OR=1.8; CI95%: 1.5-2.1; P<.001). Variations of long-term hospitalization rates depending on the type of establishment were very high, but the density of hospital beds or intensity of ambulatory activity services were not significantly linked to long-term hospitalization. The inhabitants of small urban units had significantly less risk of long-term hospitalization than those of large cities. We found no influence of material and social deprivation in the long-term hospitalizations. CONCLUSION: Long-term hospitalization in psychiatry only concerns a minority of patients but represents the fifth of the total number of days of full-time hospitalization. The recent patients were significantly less exposed to the risk of having a long-term hospitalization.

MPI/OpenMP hybrid parallel algorithm for resolution of identity second-order Møller-Plesset perturbation calculation of analytical energy gradient for massively parallel multicore supercomputers.

A massively parallel algorithm of the analytical energy gradient calculations based the resolution of identity Møller-Plesset perturbation (RI-MP2) method from the restricted Hartree-Fock reference is presented for geometry optimization calculations and one-electron property calculations of large molecules. This algorithm is designed for massively parallel computation on multicore supercomputers applying the Message Passing Interface (MPI) and Open Multi-Processing (OpenMP) hybrid parallel programming model. In this algorithm, the two-dimensional hierarchical MP2 parallelization scheme is applied using a huge number of MPI processes (more than 1000 MPI processes) for acceleration of the computationally demanding O(N5 ) step such as calculations of occupied-occupied and virtual-virtual blocks of MP2 one-particle density matrix and MP2 two-particle density matrices. The new parallel algorithm performance is assessed using test calculations of several large molecules such as buckycatcher C60 @C60 H28 (144 atoms, 1820 atomic orbitals (AOs) for def2-SVP basis set, and 3888 AOs for def2-TZVP), nanographene dimer (C96 H24 )2 (240 atoms, 2928 AOs for def2-SVP, and 6432 AOs for cc-pVTZ), and trp-cage protein 1L2Y (304 atoms and 2906 AOs for def2-SVP) using up to 32,768 nodes and 262,144 central processing unit (CPU) cores of the K computer. The results of geometry optimization calculations of trp-cage protein 1L2Y at the RI-MP2/def2-SVP level using the 3072 nodes and 24,576 cores of the K computer are presented and discussed to assess the efficiency of the proposed algorithm. © 2017 Wiley Periodicals, Inc.

Mutations of ribosomal protein S5 suppress a defect in late-30S ribosomal subunit biogenesis caused by lack of the RbfA biogenesis factor.

The in vivo assembly of ribosomal subunits requires assistance by maturation proteins that are not part of mature ribosomes. One such protein, RbfA, associates with the 30S ribosomal subunits. Loss of RbfA causes cold sensitivity and defects of the 30S subunit biogenesis and its overexpression partially suppresses the dominant cold sensitivity caused by a C23U mutation in the central pseudoknot of 16S rRNA, a structure essential for ribosome function. We have isolated suppressor mutations that restore partially the growth of an RbfA-lacking strain. Most of the strongest suppressor mutations alter one out of three distinct positions in the carboxy-terminal domain of ribosomal protein S5 (S5) in direct contact with helix 1 and helix 2 of the central pseudoknot. Their effect is to increase the translational capacity of the RbfA-lacking strain as evidenced by an increase in polysomes in the suppressed strains. Overexpression of RimP, a protein factor that along with RbfA regulates formation of the ribosome's central pseudoknot, was lethal to the RbfA-lacking strain but not to a wild-type strain and this lethality was suppressed by the alterations in S5. The S5 mutants alter translational fidelity but these changes do not explain consistently their effect on the RbfA-lacking strain. Our genetic results support a role for the region of S5 modified in the suppressors in the formation of the central pseudoknot in 16S rRNA.

A combined quantitative mass spectrometry and electron microscopy analysis of ribosomal 30S subunit assembly in E. coli.

Ribosome assembly is a complex process involving the folding and processing of ribosomal RNAs (rRNAs), concomitant binding of ribosomal proteins (r-proteins), and participation of numerous accessory cofactors. Here, we use a quantitative mass spectrometry/electron microscopy hybrid approach to determine the r-protein composition and conformation of 30S ribosome assembly intermediates in Escherichia coli. The relative timing of assembly of the 3' domain and the formation of the central pseudoknot (PK) structure depends on the presence of the assembly factor RimP. The central PK is unstable in the absence of RimP, resulting in the accumulation of intermediates in which the 3'-domain is unanchored and the 5'-domain is depleted for r-proteins S5 and S12 that contact the central PK. Our results reveal the importance of the cofactor RimP in central PK formation, and introduce a broadly applicable method for characterizing macromolecular assembly in cells.

Assessment of RV Function in Patients of (COPD).

INTRODUCTION: Chronic Obstructive Pulmonary Disease (COPD) has considerable effects on cardiac functions primarily affecting the pulmonary vasculature and then right ventricle along with left ventricle. One of the important causes of increased morbidity and mortality associated with COPD is cor pulmonale. Echocardiography provides a rapid, non-invasive method to evaluate cardiac changes. Our aim was to evaluate RVfunction in COPD as per guidelines of American Society of Echocardiography with an aim to find a simpler way of predicting cardiac morbidity. MATERIALS AND METHODS: A cross sectional observational study was conducted on 17 COPD patients attending Respiratory Medicine outdoor of R. G. KAR Medical College, Kolkata, India, through history taking, clinical examination, PFT (PFT) and Echocardiography. Statistical analysis was done by using Statistical Package for the Social Sciences (SPSS) version-17. RESULTS: Fractional area change of RV (FAC-%) was positively correlated with Forced Expiratory Volume in One Second (FEV1) (r = 0.4879), FEV1/ Forced Vital Capacity (FVC) ratio (r = 0.5048) and Peak Expiratory Flow Rate (PEFR) (r = 0.5361). There was strong negative correlation of Systolic Pulmonary Artery Pressure (SPAP) with FEV1/FVC ratio (r = -0.5553) and PEFR (r = - 0.4604). Right Index of Myocardial Performance (RIMP) of right ventricle was negatively correlated with FEV1/FVC ratio (r = - 0.598), PEFR (r = - 0.619), Forced Expiratory Flow (FEF) 25-75 (r = -0.515). Tricuspid annular plane systolic excursion (TAPSE) did not show any association with PFT parameters though it showed strong positive correlation with RV wall thickness. CONCLUSION: This study substantiates that FAC% and RIMP can be vital prognostic factors for RV function apart from SPAP, TAPSE to define RV dysfunction and predict morbidity in COPD.

Right ventricular myocardial performance index derived from tissue Doppler echocardiography is useful in differentiating apical ballooning syndrome from cardiomyopathy due to left anterior descending coronary artery disease.

BACKGROUND: Apical ballooning syndrome (ABS) and obstructive coronary artery disease of the left anterior descending coronary artery (LAD) can both result in similar left ventricular apical wall motion abnormalities. The right ventricle may more likely be involved in ABS, and its careful evaluation may help differentiate the two conditions. Therefore, the aim of this study was to determine the roles of echocardiographic measures of right ventricular (RV) function, namely, Doppler tissue imaging-derived RV index of myocardial performance (RIMP), RV basal free wall systolic excursion velocity (RV S'), and tricuspid annular plane systolic excursion, in differentiating ABS from obstructive LAD disease. METHODS: A total of 80 patients with new extensive apical left ventricular wall motion abnormalities on echocardiography who underwent coronary angiography were identified retrospectively. Patients with insufficient echocardiographic data were excluded (n = 17). Admission clinical and echocardiographic data were compared between patients with obstructive disease of the LAD (LAD group; n = 46) and those with normal coronary arteries (ABS group; n = 17). RESULTS: The ABS group had significantly greater RIMP (1.03 ± 0.22 vs 0.44 ± 0.18, P < .001). In predicting ABS, RIMP > 0.74 had sensitivity of 94%, specificity of 94%, positive predictive value of 84%, and negative predictive value of 98%, with excellent discriminatory ability (area under the receiver operating characteristic curve, 0.96 ± 0.03). Other measures of RV function (i.e., tricuspid annular plane systolic excursion and RV S') were similar between the two groups. CONCLUSIONS: Doppler tissue imaging-derived RIMP may help differentiate ABS from obstructive LAD disease with high accuracy. This easily obtainable measurement may offer a noninvasive tool to differentiate these two conditions.