Filament structure and subcellular organization of the bacterial intermediate filament-like protein crescentin.

The protein crescentin is required for the crescent shape of the freshwater bacterium (). Crescentin forms a filamentous structure on the inner, concave side of the curved cells. It shares features with eukaryotic intermediate filament (IF) proteins, including the formation of static filaments based on long and parallel coiled coils, the protein's length, structural roles in cell and organelle shape determination and the presence of a coiled coil discontinuity called the "stutter.

Efficient Empirical Valence Bond Simulations with GROMACS.

We describe a protocol to perform empirical valence bond (EVB) simulations using GROMACS software. EVB is a fast and reliable method that allows one to determine the reaction free-energy profiles in complex systems, such as enzymes, by employing classical force fields to represent a chemical reaction. Therefore, running EVB simulations is basically as fast as any classical molecular dynamics simulation, and the method uses standard free-energy calculations to map the free-energy change along a given reaction path.

Computational design of the temperature optimum of an enzyme reaction.

Cold-adapted enzymes are characterized both by a higher catalytic activity at low temperatures and by having their temperature optimum down-shifted, compared to mesophilic orthologs. In several cases, the optimum does not coincide with the onset of protein melting but reflects some other type of inactivation. In the psychrophilic α-amylase from an Antarctic bacterium, the inactivation is thought to originate from a specific enzyme-substrate interaction that breaks around room temperature.

Cryo-EM structure of the bacterial divisome core complex and antibiotic target FtsWIQBL.

In most bacteria, cell division relies on the synthesis of new cell wall material by the multiprotein divisome complex. Thus, at the core of the divisome are the transglycosylase FtsW, which synthesises peptidoglycan strands from its substrate Lipid II, and the transpeptidase FtsI that cross-links these strands to form a mesh, shaping and protecting the bacterial cell. The FtsQ-FtsB-FtsL trimeric complex interacts with the FtsWI complex and is involved in regulating its enzymatic activities; however, the structure of this pentameric complex is unknown.

Calculation of Heat Capacity Changes in Enzyme Catalysis and Ligand Binding.

It has been suggested that heat capacity changes in enzyme catalysis may be the underlying reason for temperature optima that are not related to unfolding of the enzyme. If this were to be a common phenomenon, it would have major implications for our interpretation of enzyme kinetics. In most cases, the support for the possible existence of a nonzero (negative) activation heat capacity, however, only relies on fitting such a kinetic model to experimental data.

Structure and Mechanism of a Cold-Adapted Bacterial Lipase.

The structural origin of enzyme cold-adaptation has been the subject of considerable research efforts in recent years. Comparative studies of orthologous mesophilic-psychrophilic enzyme pairs found in nature are an obvious strategy for solving this problem, but they often suffer from relatively low sequence identity of the enzyme pairs. Small bacterial lipases adapted to distinctly different temperatures appear to provide an excellent model system for these types of studies, as they may show a very high degree of sequence conservation.

The Activation Parameters of a Cold-Adapted Short Chain Dehydrogenase Are Insensitive to Enzyme Oligomerization.

The structural principles of enzyme cold adaptation are of fundamental interest both for understanding protein evolution and for biotechnological applications. It has become clear in recent years that structural flexibility plays a major role in tuning enzyme activity at low temperatures, which is reflected by characteristic changes in the thermodynamic activation parameters for psychrophilic enzymes, compared to those of mesophilic and thermophilic ones. Hence, increased flexibility of the enzyme surface has been shown to lead to a lower enthalpy and a more negative entropy of activation, which leads to higher activity in the cold.

Bacterial Actins.

A diverse set of protein polymers, structurally related to actin filaments contributes to the organization of bacterial cells as cytomotive or cytoskeletal filaments. This chapter describes actin homologs encoded by bacterial chromosomes. MamK filaments, unique to magnetotactic bacteria, help establishing magnetic biological compasses by interacting with magnetosomes.

A detailed report of the resource use and costs associated with implementation of a short stay programme for breast cancer surgery.

Background: Despite the increased attention for assessing the effectiveness of implementation strategies, most implementation studies provide little or no information on its associated costs. The focus of the current study was to provide a detailed report of the resource use and costs associated with implementation of a short stay programme for breast cancer surgery in four Dutch hospitals.

Methods: The analysis was performed alongside a multi-centre implementation study.

Prognostic Significance of Tumor-Positive Internal Mammary Sentinel Lymph Nodes in Breast Cancer: A Multicenter Cohort Study.

Introduction: The introduction of the sentinel lymph node biopsy (SLNB) in breast cancer has renewed interest in lymphatic drainage to the internal mammary (IM) nodes. The clinical impact of tumor positive IM nodes is not completely clear. This study evaluated the incidence and impact on overall survival of metastatic IM SLNs.

Bacterial actin MreB forms antiparallel double filaments.

Filaments of all actin-like proteins known to date are assembled from pairs of protofilaments that are arranged in a parallel fashion, generating polarity. In this study, we show that the prokaryotic actin homologue MreB forms pairs of protofilaments that adopt an antiparallel arrangement in vitro and in vivo. We provide an atomic view of antiparallel protofilaments of Caulobacter MreB as apparent from crystal structures.

A bipolar spindle of antiparallel ParM filaments drives bacterial plasmid segregation.

To ensure their stable inheritance by daughter cells during cell division, bacterial low-copy-number plasmids make simple DNA segregating machines that use an elongating protein filament between sister plasmids. In the ParMRC system of the Escherichia coli R1 plasmid, ParM, an actinlike protein, forms the spindle between ParRC complexes on sister plasmids. By using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins.

Occult Breast Cancer due to Multiple Calcified Hamartomas in a Patient with Cowden Syndrome.

Cowden syndrome (CS) is an autosomal dominant disorder characterized by presence of multiple hamartomas, and other benign and malignant abnormalities of the breasts, skin, thyroid, endometrium, gastrointestinal tract, and central nervous system. Hamartomas are benign, developmentally disorganized tumors that can develop in any of the above mentioned organs. The presence of massive calcifications in the breasts in very young women is an indication to perform a breast MRI to exclude a neoplasm since, like in the current case report, presence of breast calcifications may obscure a neoplasm.

Direct membrane binding by bacterial actin MreB.

Bacterial actin MreB is one of the key components of the bacterial cytoskeleton. It assembles into short filaments that lie just underneath the membrane and organize the cell wall synthesis machinery. Here we show that MreB from both T.

Economic evaluation of four follow-up strategies after curative treatment for breast cancer: results of an RCT.

Background: An economic evaluation was performed alongside a randomised controlled trial (ISRCTN 74071417) investigating the cost-effectiveness of nurse-led telephone follow-up instead of hospital visits, and of a short educational group programme (EGP) in the first year after breast cancer treatment.

Method: This economic evaluation (n = 299) compared the one-year costs and the effects of four follow-up strategies: (1) hospital follow-up; (2) nurse-led telephone follow-up; (3) hospital follow-up plus EGP; and (4) nurse-led telephone follow-up plus EGP. Costs were measured using cost diaries and hospital registrations.

Nurse-led telephone follow-up and an educational group programme after breast cancer treatment: results of a 2 × 2 randomised controlled trial.

Objective: To investigate whether frequent hospital follow-up in the first year after breast cancer treatment might partly be replaced by nurse-led telephone follow-up without deteriorating health-related quality of life (HRQoL), and whether a short educational group programme (EGP) would enhance HRQoL.

Patients And Methods: A multicentre pragmatic randomised controlled trial (RCT) with a 2×2 factorial design was performed among 320 breast cancer patients who were treated with curative intent. Participants were randomised to follow-up care as usual (3-monthly outpatient clinic visits), nurse-led telephone follow-up, or the former strategies combined with an educational group programme.

A patient-centred instrument for assessment of quality of breast cancer care: results of a pilot questionnaire.

Background: In several breast cancer research environments, there was a need to develop a questionnaire that would (1) provide data on how breast cancer patients experience healthcare services, (2) address issues corresponding with patients' needs and expectations and (3) produce useful data for quality assessment and improvement projects aimed at breast cancer care. This article describes the first part of the quantitative process of item selection, instrument construction and optimisation based on the results of a pilot questionnaire.

Methods: Based on qualitative research, a pilot questionnaire with items formulated as "performance" and "importance" statements was developed and sent to all breast cancer patients operated on in the previous 3-15 months in five participating hospitals.

Patients' opinions on quality of care before and after implementation of a short stay programme following breast cancer surgery.

Purpose: To assess breast cancer patients' opinions on quality of care during an implementation study on short hospital stay, and to formulate patient inspired targets for further quality improvement based on results of the QUOTE (Quality of Care Through the Patients' Eyes) breast cancer instrument.

Results: Quality of patient education regarding activities at home was in need of improvement in both measurements. Quality of services delivered by the surgeon improved somewhat after implementation.

Cost-effectiveness of a short stay admission programme for breast cancer surgery.

Background: Short stay (admission, surgery, and discharge the same day or within 24 hours) following breast cancer surgery is part of an established care protocol but as yet not well implemented in Europe. Alongside a before-after multi-centre implementation study, an economic evaluation was performed exploring the cost-effectiveness of a short stay programme (SSP) versus care as usual (CAU).

Material And Methods: In the implementation study, 324 patients were included.

Bacterial actin MreB assembles in complex with cell shape protein RodZ.

Bacterial actin homologue MreB is required for cell shape maintenance in most non-spherical bacteria, where it assembles into helical structures just underneath the cytoplasmic membrane. Proper assembly of the actin cytoskeleton requires RodZ, a conserved, bitopic membrane protein that colocalises to MreB and is essential for cell shape determination. Here, we present the first crystal structure of bacterial actin engaged with a natural partner and provide a clear functional significance of the interaction.

Implementation of a short-stay programme after breast cancer surgery.

Background: : Short-stay breast cancer surgery (24 h or day case) is not common practice in Europe. This before-after comparative study was carried out to test the feasibility of systematically implementing a care programme incorporating short-stay admission using strategies tailored to individual hospital needs, and to assess safety and facilitating factors.

Methods: : Patients with breast cancer from four Dutch hospitals participated.

Sentinel lymph node biopsy in patients with thin melanoma: occurrence of nodal metastases and its prognostic value.

We identified the proportion of positive sentinel lymph node biopsies (SNBs) in patients treated for thin melanoma (Breslow thickness View Article and Find Full Text PDF

Breast MRI in clinically and mammographically occult breast cancer presenting with an axillary metastasis: a systematic review.

Background: Axillary metastatic lymphadenopathy with no primary tumour identified in the breast on physical examination, mammography or ultrasound is referred to as occult breast cancer. The goal of this systematic review is to give an overview of the value and additional considerations of using breast MRI in occult breast cancer.

Methods: The databases of Pubmed, Embase, CINAHL and the Cochrane library were searched for studies addressing the use of breast MRI in occult breast cancer.

Is there an indication for routine chest X-ray in initial staging of melanoma?

Background: Our aim was to evaluate therapeutic consequences of preoperative staging with Chest X-ray (CXR) in patients with a primary melanoma planned for sentinel node biopsy (SNB).

Methods: From a prospective database, 248 medical records of patients treated for primary melanoma were extracted. CXRs were made prior to SNB, and examined by radiologists.

Thick melanoma: prognostic value of positive sentinel nodes.

Background: Sentinel lymph node biopsy (SNB) is a widely accepted procedure used to accurately stage patients with melanoma. Its value in patients with thick melanoma (Breslow thickness >4 mm) is reason for discussion because of the generally poor prognosis of these patients. The purpose of this study was to report on the incidence of SNB positivity in patients with thick melanoma and to analyze the prognostic value of SNB in these patients.