βα-Hairpin Clamps Brace βαβ Modules and Can Make Substantive Contributions to the Stability of TIM Barrel Proteins

Non-local hydrogen bonding interactions between main chain amide hydrogen atoms and polar side chain acceptors that bracket consecutive βα or αβ elements of secondary structure in αTS from E. coli, a TIM barrel protein, have previously been found to contribute 4–6 kcal mol−1 to the stability of the native conformation. Experimental analysis of similar βα-hairpin clamps in a homologous pair of TIM barrel proteins of low sequence identity, IGPS from S. solfataricus and E. coli, reveals that this dramatic enhancement of stability is not unique to αTS. A survey of 71 TIM barrel proteins demonstrates a 4-fold symmetry for the placement of βα-hairpin clamps, bracing the fundamental βαβ building block and defining its register in the (βα)8 motif. The preferred sequences and locations of βα-hairpin clamps will enhance structure prediction algorithms and provide a strategy for engineering stability in TIM barrel proteins

Eco-efficiency measurement and material balance principle:an application in power plants Malmquist Luenberger Index

Incorporating Material Balance Principle (MBP) in industrial and agricultural performance measurement systems with pollutant factors has been on the rise in recent years. Many conventional methods of performance measurement have proven incompatible with the material flow conditions. This study will address the issue of eco-efficiency measurement adjusted for pollution, taking into account materials flow conditions and the MBP requirements, in order to provide ‘real’ measures of performance that can serve as guides when making policies. We develop a new approach by integrating slacks-based measure to enhance the Malmquist Luenberger Index by a material balance condition that reflects the conservation of matter. This model is compared with a similar model, which incorporates MBP using the trade-off approach to measure productivity and eco-efficiency trends of power plants. Results reveal similar findings for both models substantiating robustness and applicability of the proposed model in this paper

Metal-Free ALS Variants of Dimeric Human Cu,Zn-Superoxide Dismutase Have Enhanced Populations of Monomeric Species

Amino acid replacements at dozens of positions in the dimeric protein human, Cu,Zn superoxide dismutase (SOD1) can cause amyotrophic lateral sclerosis (ALS). Although it has long been hypothesized that these mutations might enhance the populations of marginally-stable aggregation-prone species responsible for cellular toxicity, there has been little quantitative evidence to support this notion. Perturbations of the folding free energy landscapes of metal-free versions of five ALS-inducing variants, A4V, L38V, G93A, L106V and S134N SOD1, were determined with a global analysis of kinetic and thermodynamic folding data for dimeric and stable monomeric versions of these variants. Utilizing this global analysis approach, the perturbations on the global stability in response to mutation can be partitioned between the monomer folding and association steps, and the effects of mutation on the populations of the folded and unfolded monomeric states can be determined. The 2- to 10-fold increase in the population of the folded monomeric state for A4V, L38V and L106V and the 80- to 480-fold increase in the population of the unfolded monomeric states for all but S134N would dramatically increase their propensity for aggregation through high-order nucleation reactions. The wild-type-like populations of these states for the metal-binding region S134N variant suggest that even wild-type SOD1 may also be prone to aggregation in the absence of metals

Mutations in the cytoplasmic tail of influenza A virus neuraminidase affect incorporation into virions.

The significance of the conserved cytoplasmic tail sequence of influenza A virus neuraminidase (NA) was analyzed by the recently developed reverse genetics technique (W. Luytjes, M. Krystal, M. Enami, J. D. Parvin, and P. Palese, Cell 59:1107-1113, 1989). A chimeric influenza virus A/WSN/33 NA containing the influenza B virus cytoplasmic tail rescued influenza A virus infectivity. The transfectant virus had less NA incorporated into virions than A/WSN/33, indicating that the cytoplasmic tail of influenza virus NA plays a role in incorporation of NA into virions. However, these results also suggest that the influenza A virus and influenza B virus cytoplasmic tail sequences share common features that lead to the production of infectious virus. Transfectant virus was obtained with all cytoplasmic tail mutants generated by site-directed mutagenesis of the influenza A virus tail, except for the mutant resulting from substitution of the conserved proline residue, presumably because of its contribution to the secondary structure of the tail. No virus was rescued when the cytoplasmic tail was deleted, indicating that the cytoplasmic tail is essential for production of the virus. The virulence of the transfectant viruses in mice was directly proportional to the amount of NA incorporated. The importance of the NA cytoplasmic tail in virus assembly and virulence has implications for use in developing antiviral strategies

Abdominal mass secondary to actinomyces infection: An unusual presentation and its treatment

Abdominal actinomycosis may appear as an abdominal mass and/or abscess. This mass can mimic a malignant tumour. The diagnosis and management of abdominal actinomycosis will be discussed through a review of the literature and a case report from our own institution. The patient was a 17-year-old boy who presented with abdominal discomfort and a palpable right lower quadrant mass defined on CT scan. He underwent en bloc resection of the mass for a presumed diagnosis of tumour of uncertain type with intestinal involvement. The diagnosis was reversed, when histology revealed filamentous organisms consistent with actinomyces. He was treated with high dose penicillin for several weeks and was discharged from the hospital taking penicillin orally. Preoperative diagnosis of abdominal actinomycosis is difficult. An accurate diagnosis is always obtained in a histological or microbiological examination, often requiring surgical resection. Recognition is important because successful treatment requires combined surgery and prolonged penicillin treatment

Case Report - Abdominal mass secondary to actinomyces infection: An unusual presentation and its treatment

Abdominal actinomycosis may appear as an abdominal mass and/or abscess. This mass can mimic a malignant tumour. The diagnosis and management of abdominal actinomycosis will be discussed through a review of the literature and a case report from our own institution. The patient was a 17-year-old boy who presented with abdominal discomfort and a palpable right lower quadrant mass defined on CT scan. He underwent en bloc resection of the mass for a presumed diagnosis of tumour of uncertain type with intestinal involvement. The diagnosis was reversed, when histology revealed filamentous organisms consistent with actinomyces. He was treated with high dose penicillin for several weeks and was discharged from the hospital taking penicillin orally. Preoperative diagnosis of abdominal actinomycosis is difficult. An accurate diagnosis is always obtained in a histological or microbiological examination, often requiring surgical resection. Recognition is important because successful treatment requires combined surgery and prolonged penicillin treatment

Subphrenic abscess resulting in resection of the lower basal segment of the right lung: A severe complication following laparoscopic appendectomy

We report the case of an 18-year-old boy who developed an intrathoracic abscess with rupture of the diaphragm following a laparoscopic appendectomy (LA) for a perforated appendicitis. LA is an established procedure in the treatment of appendicitis. It is a safe and efficacious technique, but several complications can occur with this procedure, and surgeons should be aware of the potential dangers. Herein, we present a previously unreported thoracic complication following an LA