Crystal structure of Lon protease: molecular architecture of gated entry to a sequestered degradation chamber

Lon proteases are distributed in all kingdoms of life and are required for survival of cells under stress. Lon is a tandem fusion of an AAA+ molecular chaperone and a protease with a serine‐lysine catalytic dyad. We report the 2.0‐Å resolution crystal structure of Thermococcus onnurineus NA1 Lon (TonLon). The structure is a three‐tiered hexagonal cylinder with a large sequestered chamber accessible through an axial channel. Conserved loops extending from the AAA+ domain combine with an insertion domain containing the membrane anchor to form an apical domain that serves as a gate governing substrate access to an internal unfolding and degradation chamber. Alternating AAA+ domains are in tight‐ and weak‐binding nucleotide states with different domain orientations and intersubunit contacts, reflecting intramolecular dynamics during ATP‐driven protein unfolding and translocation. The bowl‐shaped proteolytic chamber is contiguous with the chaperone chamber allowing internalized proteins direct access to the proteolytic sites without further gating restrictions.     

Genome sequence of benzo(a)pyrene-degrading bacterium Novosphingobium pentaromativorans US6-1

Novosphingobium pentaromativorans US6-1 showed a good ability to degrade high-molecular-weight polycyclic aromatic hydrocarbons. We report the draft genome sequence of strain US6-1, which contains a main chromosome (5,096,413 bp, G+C content of 63.1%) and two plasmids (188,476 and 60,085 bp). The majority of the aromatic-hydrocarbon-degrading genes are encoded in the larger plasmid.     

Separation of saccharides derivatized with 2-aminobenzoic acid by capillary electrophoresis and their structural consideration by nuclear magnetic resonance

Saccharides including mono- and disaccharides were quantitatively derivatized with 2-aminobenzoic acid (2-AA). These derivatives were then separated by capillary zone electrophoresis with UV detection using 50mM sodium phosphate buffer as the running electrolyte solution. In particular, the saccharide derivatives with the same molecular weight as 2-AA aldohexoses (mannose and glucose) and 2-AA aldopentoses (ribose and xylose) were well separated. The underlying reasons for separation were explored by studying their structural data using 1H and 13C NMR. It was found that the configurational difference between their hydroxyl group at C2 or C3 could cause the difference in Stokes' radii between their molecules and thus lead to different electrophoretic mobilities. The correlation between the electrophoretic behavior of these carbohydrate derivatives and their structures was studied utilizing the calculated molecular models of the 2-AA-labeled mannose, glucose, ribose, and xylose.     

Comparative seedling ecology of eight North American spruce (Picea) species in relation to their geographic ranges

BACKGROUND AND AIMS: Allowing for dispersal limitation, a species' geographic distribution should reflect its environmental requirements. Comparisons among closely related species should reveal adaptive differentiation in species characteristics that are consistent with their differences in geographic distribution. This expectation was tested by comparing characteristics of seedlings of spruce species in relation to environmental factors representative of their current natural ranges. METHODS: Seedlings were grown from a total of 34 populations representing eight North American spruce (Picea) species in a controlled environment chamber for 140 d. Traits related to the potential of seedling establishment, including tolerance to stress events (high temperature, desiccation) were evaluated. Correlations were sought between these characteristics and modal values of latitude, aridity and continentality in the geographic range of each species. KEY RESULTS: Many seedling traits changed significantly in response to stress events, but only the response of chlorophyll concentration differed significantly among species. Components of seedling growth were good correlates of species distribution. Seedling relative growth rate (RGR) and specific leaf area (SLA) were positively correlated with latitude, and leaf weight ratio (LWR) negatively correlated with aridity. Seed mass was negatively correlated with latitude. CONCLUSIONS: Relationships found between seedling traits and geographical variation in environmental conditions suggest that factors such as temperature regime, water availability and perhaps litter depth affect species range in North American spruces. Seedling characteristics appear to be elements in a reasonably distinct environmental niche for each spruce species at the continental scale.     

Modulation of TNF-alpha gene expression by IFN-gamma and pamidronate in murine macrophages: regulation by STAT1-dependent pathways

Aminobisphosphonates are drugs used in the treatment of hypercalcemia, Paget's disease, osteoporosis, and malignancy. Some patients treated with aminobisphosphonates have a transient febrile reaction that may be caused by an increased serum concentration of proinflammatory cytokines. Aminobisphosphonates induce the production of certain proinflammatory cytokines in vitro, especially in cells of monocytic lineage. A unique feature of aminobisphosphonates is that they bind the Vgamma2Vdelta2 class of T cells, which are found only in primates, and stimulate cytokine production. The effects of aminobisphosphonates on other cells, including macrophages, are incompletely understood. We show in this study that treatment of murine macrophages with pamidronate, a second generation aminobisphosphonate, induces TNF-alpha production. Furthermore, pretreatment of murine macrophages with pamidronate before stimulation with IFN-gamma significantly augments IFN-gamma-dependent production of TNF-alpha. This pamidronate-mediated augmentation of TNF-alpha production results in sustained phosphorylation of the tyrosine residue at position 701 of STAT1 after IFN-gamma treatment. Our data suggest that this sustained phosphorylation results from inhibition of protein tyrosine phosphatase activity. We also show that pamidronate treatment increases TNF-alpha production in vivo in mice. Pamidronate-augmented TNF-alpha production by macrophages might be a useful strategy for cytokine-based anticancer therapy.     

A novel <Emphasis Type="Italic">Dictyostelium</Emphasis> RasGEF required for chemotaxis and development

Background  

Ras proteins are guanine-nucleotide-binding enzymes that couple cell surface receptors to intracellular signaling pathways controlling cell proliferation and differentiation, both in lower and higher eukaryotes. They act as molecular switches by cycling between active GTP and inactive GDP-bound states, through the action of two classes of regulatory proteins: a) guanine nucleotide exchange factor (GEFs) and b) GTP-ase activating proteins (GAPs). Genome wide analysis of the lower eukaryote Dictyostelium discoideum revealed a surprisingly large number of Ras Guanine Nucleotide Exchange Factors (RasGEFs). RasGEFs promote the activation of Ras proteins by catalyzing the exchange of GDP for GTP, thus conferring to RasGEFs the role of main activator of Ras proteins. Up to date only four RasGEFs, which are all non-redundant either for growth or development, have been characterized in Dictyostelium. We report here the identification and characterization of a fifth non-redundant GEF, RasGEFM.     

Association between Poor Glycemic Control,Impaired Sleep Quality,and Increased Arterial Thickening in Type 2 Diabetic Patients

Objective

Poor sleep quality is an independent predictor of cardiovascular events. However, little is known about the association between glycemic control and objective sleep architecture and its influence on arteriosclerosis in patients with type-2 diabetes mellitus (DM). The present study examined the association of objective sleep architecture with both glycemic control and arteriosclerosis in type-2 DM patients.

Design

Cross-sectional study in vascular laboratory.

Methods

The subjects were 63 type-2 DM inpatients (M/F, 32/31; age, 57.5±13.1) without taking any sleeping promoting drug and chronic kidney disease. We examined objective sleep architecture by single-channel electroencephalography and arteriosclerosis by carotid-artery intima-media thickness (CA-IMT).

Results

HbA1c was associated significantly in a negative manner with REM sleep latency (interval between sleep-onset and the first REM period) (β=-0.280, p=0.033), but not with other measurements of sleep quality. REM sleep latency associated significantly in a positive manner with log delta power (the marker of deep sleep) during that period (β=0.544, p=0.001). In the model including variables univariately correlated with CA-IMT (REM sleep latency, age, DM duration, systolic blood pressure, and HbA1c) as independent variables, REM sleep latency (β=-0.232, p=0.038), but not HbA1c were significantly associated with CA-IMT. When log delta power was included in place of REM sleep latency, log delta power (β=-0.257, p=0.023) emerged as a significant factor associated with CA-IMT.

Conclusions

In type-2 DM patients, poor glycemic control was independently associated with poor quality of sleep as represented by decrease of REM sleep latency which might be responsible for increased CA-IMT, a relevant marker for arterial wall thickening.     

Assessment of Cancer-Related Fatigue,Pain, and Quality of Life in Cancer Patients at Palliative Care Team Referral: A Multicenter Observational Study (JORTC PAL-09)

Introduction

Cancer-related fatigue greatly influences quality of life in cancer patients; however, no specific treatments have been established for cancer-related fatigue, and at present, no medication has been approved in Japan. Systematic research using patient-reported outcome to examine symptoms, particularly fatigue, has not been conducted in palliative care settings in Japan. The objective was to evaluate fatigue, pain, and quality of life in cancer patients at the point of intervention by palliative care teams.

Materials and Methods

Patients who were referred to palliative care teams at three institutions and met the inclusion criteria were invited to complete the Brief Fatigue Inventory, Brief Pain Inventory, and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative.

Results

Of 183 patients recruited, the majority (85.8%) were diagnosed with recurrence or metastasis. The largest group (42.6%) comprised lung cancer patients, of whom 67.2% had an Eastern Cooperative Oncology Group Performance Status of 0–1. The mean value for global health status/quality of life was 41.4, and the highest mean European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative symptom item score was for pain (51.0). The mean global fatigue score was 4.1, and 9.8%, 30.6%, 38.7%, and 20.8% of patients’ fatigue severity was classified as none (score 0), mild (1–3), moderate (4–6), and severe (7–10), respectively.

Discussion

Cancer-related fatigue, considered to occur more frequently in cancer patients, was successfully assessed using patient-reported outcomes with the Brief Fatigue Inventory for the first time in Japan. Results suggested that fatigue is potentially as problematic as pain, which is the main reason for palliative care.     

Isometric yoga improves the fatigue and pain of patients with chronic fatigue syndrome who are resistant to conventional therapy: a randomized,controlled trial

Background

Patients with chronic fatigue syndrome (CFS) often complain of persistent fatigue even after conventional therapies such as pharmacotherapy, cognitive behavioral therapy, or graded exercise therapy. The aim of this study was to investigate in a randomized, controlled trial the feasibility and efficacy of isometric yoga in patients with CFS who are resistant to conventional treatments.

Methods

This trial enrolled 30 patients with CFS who did not have satisfactory improvement after receiving conventional therapy for at least six months. They were randomly divided into two groups and were treated with either conventional pharmacotherapy (control group, n?=?15) or conventional therapy together with isometric yoga practice that consisted of biweekly, 20-minute sessions with a yoga instructor and daily in-home sessions (yoga group, n?=?15) for approximately two months. The short-term effect of isometric yoga on fatigue was assessed by administration of the Profile of Mood Status (POMS) questionnaire immediately before and after the final 20-minute session with the instructor. The long-term effect of isometric yoga on fatigue was assessed by administration of the Chalder’s Fatigue Scale (FS) questionnaire to both groups before and after the intervention. Adverse events and changes in subjective symptoms were recorded for subjects in the yoga group.

Results

All subjects completed the intervention. The mean POMS fatigue score decreased significantly (from 21.9?±?7.7 to 13.8?±?6.7, P?<?0.001) after a yoga session. The Chalder’s FS score decreased significantly (from 25.9?±?6.1 to 19.2?±?7.5, P?=?0.002) in the yoga group, but not in the control group. In addition to the improvement of fatigue, two patients with CFS and fibromyalgia syndrome in the yoga group also reported pain relief. Furthermore, many subjects reported that their bodies became warmer and lighter after practicing isometric yoga. Although there were no serious adverse events in the yoga group, two patients complained of tiredness and one of dizziness after the first yoga session with the instructor.

Conclusions

Isometric yoga as an add-on therapy is both feasible and successful at relieving the fatigue and pain of a subset of therapy-resistant patients with CFS.

Trial registration

University Hospital Medical Information Network (UMIN CTR) UMIN 000009646.