Chloroplast Proteins without Cleavable Transit Peptides

Most chloroplast proteins (cp proteins) are nucleus-encoded, synthesized on cytosolic ribosomes as precursor proteins containing a presequence (cTP), and post-translationally imported via the Tic/Toc complex into the organelle, where the cTP is removed. Only a few unambiguous instances of cp proteins that do not require cTPs (non-canonical cp proteins) have been reported so far. However, the survey of data from large-scale proteomic studies presented here suggests that the fraction of such proteins in the total cp proteome might be as large as approximately 30%. To explore this discrepancy, we chose a representative set of 28 putative non-canonical cp proteins, and used in vitro import and Red Fluorescent Protein (RFP)-fusion assays to determine their sub-cellular destinations. Four proteins, including embryo defective 1211, glycolate oxidase 2, protein disulfide isomerase-like protein (PDII), and a putative glutathione S-transferase, could be unambiguously assigned to the chloroplast. Several others ('potential cp proteins') were found to be imported into chloroplasts in vitro, but failed to localize to the organelle when RFP was fused to their C-terminal ends. Extrapolations suggest that the fraction of cp proteins that enter the inner compartments of the organelle, although they lack a cTP, might be as large as 11.4% of the total cp proteome. Our data also support the idea that cytosolic proteins that associate with the cp outer membrane might account for false positive cp proteins obtained in earlier studies

Use of smartphone photos to document the oral care status of nursing home residents

Objective Investigate whether clinically assessed oral care status by an external dentist can be replicated using smartphone photographs. Background Many people with care needs have poor oral hygiene. To help maintain oral health, caregivers require a simple way of communicating oral care status to the dental team. Materials and Methods Cross-sectional study in which smartphone photographs of the oral and prosthetic care situation of N = 50 nursing-home patients (mean age 85.6 [SD 6] years, 74% women) were assessed by two blinded, external examiners (D1/D2) and compared with clinical assessments made by the onsite dentist who also took the photographs (D0). Intraoral care status was clinically evaluated using the modified Plaque Index for Long-Term Care (PI-LTC) and Denture Hygiene Index (DHI). The intraclass correlation coefficient (ICC) determined correlations between clinical and photographic findings. Results The ICC was assessed for the PI-LTC (upper jaw, n = 41; lower jaw, n = 49) and DHI (upper jaw, n = 25; lower jaw, n = 18). The DHI showed excellent reliability between clinical assessment and smartphone evaluation for the determination of positive surfaces (ICC: upper 0.91 [95% confidence interval (CI) 0.83-0.96], P < 0.001; lower 0.95 [95% CI 0.89-0.98], P < 0.001). The PI-LTC showed good reliability between clinical assessment (D0) and D1/D2 for determination of vestibular plaque (ICC: upper 0.84 [95% CI 0.74-0.91], P < 0.001; lower 0.87 [95% CI 0.79-0.92], P < 0.001). Conclusions Although limited, this pilot study demonstrated that standardised smartphone photographs can simply communicate the intraoral care status of patients who have difficulties accessing their dentist. This should be considered when planning improved communication between dentists, care recipients, and their support network

Circadian rhythms and influencing factors of xerostomia among Parkinson's disease patients

Objectives Parkinson's disease (PD) patients suffer from xerostomia, but limited information exists regarding associations with dysphagia, drooling, daily habits, PD characteristics, or possible circadian rhythms. Subjects and methods A questionnaire was administered, including (a) clinical characteristics (comorbidities, prescribed medications, levodopa equivalent daily dose [LEDD], disease duration); (b) self-assessment of dysphagia, xerostomia, drooling (10-cm visual analogue scale [VAS]); (c) 24-hr diary of motor impairment, dyskinesia, xerostomia, dysphagia, drooling, daily habits. Results Of 75 PD patients who completed the study, 67% reported dysphagia (mean +/- standard deviation VAS 4 +/- 2), 76% drooling (5 +/- 2), 77% xerostomia (5 +/- 2). Xerostomia was associated with comorbidities (p = 0.021) and smoking (p = 0.010) and affected by tremor (p = 0.003), dyskinesia (p = 0.010), dysphagia (p < 0.001), food intake (p = 0.005), sleep (p = 0.011), age (p = 0.018), medication intake (p = 0.063), LEDD (p = 0.052), daytime (p = 0.075), disease duration (p = 0.004). Xerostomia peaked at 9 a.m. and 9 p.m. Conclusions PD patients suffer from xerostomia, dysphagia, and drooling. Subjective dysphagia is associated with drooling and xerostomia, but drooling prevalence or intensity does not influence xerostomia symptoms. Tremor, dyskinesia, and disease duration, which characterise PD, affect xerostomia. Additionally, food intake, sleep, age, LEDD, and daytime (peaks at 9 a.m. and 9 p.m.) increase xerostomia occurrence. This knowledge may improve dentists' advice to patients and aid development of patient-centred, symptom-relieving products

Impact of an interdisciplinary curriculum for dental students (GeriDent-Cologne) on attitudes and awareness towards older people and geriatric conditions

Introduction Training of dental students in the treatment of older patients must also consider the multiple chronic medical conditions that may be present. We developed an interdisciplinary gerodontology training curriculum for dental students (GeriDent-Cologne) to investigate its influence on the attitudes and expectancies of dental students towards the treatment of older patients. Materials and methods The curriculum (given to fourth-year students) comprised five clinical examination stations that simulated different medical conditions affecting older people. Students were able to experience related issues first hand, express their fears and problems concerning dental treatment in older people and, through discussion with the supervisor, develop strategies to overcome these difficulties and enhance treatment. An extended version of the Los Angeles Geriatric Attitudes Scale was given to fourth- and fifth-year students (who acted as controls) over one semester. Results Dental students had a positive attitude towards older people, and their attitude did not change after attending the curriculum. However, participating in GeriDent-Cologne had a significant beneficial impact on the feeling of being prepared to treat older people, led to a significantly greater understanding of the impact of medical issues and resulted in a considerably higher level of geriatric clinical knowledge over time. Conclusions GeriDent-Cologne led to positive and semester-long changes in awareness and knowledge of specific geriatric problems that influence dental treatment. We recommend the curriculum as a blueprint for the module of senior dentistry implemented in the new German dental licencing regulations

Objective masticatory efficiency and subjective quality of masticatory function among patients with periodontal disease

Aims To examine patient-centred clinical outcomes for objective masticatory efficiency (OME) and subjective quality of masticatory function (QMF) among periodontitis patients using test methods easily applicable in daily practice. Materials and Methods Cross-sectional investigation of patients undergoing supportive periodontal therapy (n = 224). Outcomes included OME and QMF related to periodontitis characteristics. Results OME and QMF were associated (x(2) = 0.252,p = 0.037) and showed highest values in stage 4 according to the new classification of periodontal disease. There were correlations particularly in stage 2 between OME and number of teeth (x(2) = -0.317,p < 0.001), Quigley-Hein Index (x(2) = 0.152,p = 0.031), attachment level (x(2) = 0.268,p < 0.001), probing depths (x(2) = 0.185,p = 0.006), tooth mobility (x(2) = 0.147,p = 0.031) and functional occlusal units (x(2) = -0.423,p < 0.001) but not bleeding on probing. A trend existed between QMF and number of teeth (x(2) = -0.237,p = 0.050) and functional occlusal units (x(2) = 0.238,p = 0.058), but not other periodontal findings. Conclusions OME and QMF values represent each other and are highest in stage 4. Periodontitis findings influence masticatory efficiency particularly in stage 2, but gingival inflammation does not. Number of teeth and functional occlusal units are associated with QMF, while periodontitis findings have less impact. An assessment of mastication should be routinely included in the diagnosis of periodontitis patients in all stages

Structure and Evolution of N-domains in AAA Metalloproteases

AbstractMetalloproteases of the AAA (ATPases associated with various cellular activities) family play a crucial role in protein quality control within the cytoplasmic membrane of bacteria and the inner membrane of eukaryotic organelles. These membrane-anchored hexameric enzymes are composed of an N-terminal domain with one or two transmembrane helices, a central AAA ATPase module, and a C-terminal Zn2+-dependent protease. While the latter two domains have been well studied, so far, little is known about the N-terminal regions. Here, in an extensive bioinformatic and structural analysis, we identified three major, non-homologous groups of N-domains in AAA metalloproteases. By far, the largest one is the FtsH-like group of bacteria and eukaryotic organelles. The other two groups are specific to Yme1: one found in plants, fungi, and basal metazoans and the other one found exclusively in animals. Using NMR and crystallography, we determined the subunit structure and hexameric assembly of Escherichia coli FtsH-N, exhibiting an unusual α+β fold, and the conserved part of fungal Yme1-N from Saccharomyces cerevisiae, revealing a tetratricopeptide repeat fold. Our bioinformatic analysis showed that, uniquely among these proteins, the N-domain of Yme1 from the cnidarian Hydra vulgaris contains both the tetratricopeptide repeat region seen in basal metazoans and a region of homology to the N-domains of animals. Thus, it is a modern-day representative of an intermediate in the evolution of animal Yme1 from basal eukaryotic precursors