Emergence of Phytobacter diazotrophicus carrying an IncA/C2 plasmid harboring bla NDM-1 in Tokyo, Japan.

Phytobacter diazotrophicus is an Enterobacterales species that was originally identified as a plant growth-promoting, Gram-negative bacterium. Recently, this species has been recognized as relevant to opportunistic human and nosocomial infections in clinical settings. Its frequent misidentification as other Enterobacterales species from clinical examination occasionally causes a delay in the identification of nosocomial outbreaks. Here, we report the emergence of New Delhi metallo-ß-lactamase (NDM)-producing P. diazotrophicus isolated from hospitalized pediatric patients and hospital environments in Tokyo, Japan. In our case, these isolates were found during an investigation of carbapenem-resistant Enterobacterales in relation to nosocomial infections. Whole-genome sequencing is useful for overcoming the difficulty of species identification. Furthermore, we found that bla NDM-1 was carried by an IncA/C2 plasmid (approximately 170 kbp), which was transferrable from the clinical isolates to the recipient strain Escherichia coli J53. Our study demonstrated that P. diazotrophicus behaves as a carrier of bla NDM-harboring plasmids, potentially disseminating resistance to carbapenems among Enterobacterales. IMPORTANCE Early detection of nosocomial outbreaks is important to minimize the spread of bacteria. When an outbreak is caused by multidrug-resistant bacteria such as carbapenem-resistant Enterobacterales, a delay in findings makes it difficult to control it because such bacteria often spread not only among human patients but also in hospital environments. Phytobacter diazotrophicus, an Enterobacterales species that has recently been found to be relevant to clinical settings, is often misidentified as other bacteria in clinical laboratories. Here, we found NDM-producing P. diazotrophicus in hospitalized pediatric patients and their environment in Tokyo, Japan. Given that the isolates carried bla NDM-1-harboring transferrable plasmids, the influence of such bacteria could be greater with the mediation of horizontal transfer of carbapenem resistance. Our findings suggest that P. diazotrophicus should be recognized as an NDM-carrier, for which more attention should be paid in clinical settings.

Recent Clinical Treatment and Basic Research on the Alveolar Bone.

The periodontal ligament is located between the bone (alveolar bone) and the cementum of the tooth, and it is connected by tough fibers called Sharpey's fibers. To maintain healthy teeth, the foundation supporting the teeth must be healthy. Periodontal diseases, also known as tooth loss, cause the alveolar bone to dissolve. The alveolar bone, similar to the bones in other body parts, is repeatedly resorbed by osteoclasts and renewed by osteogenic cells. This means that an old bone is constantly being resorbed and replaced by a new bone. In periodontal diseases, the alveolar bone around the teeth is absorbed, and as the disease progresses, the alveolar bone shrinks gradually. In most cases, the resorbed alveolar bone does not return to its original form even after periodontal disease is cured. Gum covers the tooth surface so that it matches the shape of the resorbed alveolar bone, exposing more of the tooth surface than before, making the teeth look longer, leaving gaps between the teeth, and in some cases causing teeth to sting. Previously, the only treatment for periodontal diseases was to stop the disease from progressing further before the teeth fell out, and restoration to the original condition was almost impossible. However, a treatment method that can help in the regeneration of the supporting tissues of the teeth destroyed by periodontal diseases and the restoration of the teeth to their original healthy state as much as possible is introduced. Recently, with improvements in implant material properties, implant therapy has become an indispensable treatment method in dentistry and an important prosthetic option. Treatment methods and techniques, which are mainly based on experience, have gradually accumulated scientific evidence, and the number of indications for treatment has increased. The development of bone augmentation methods has contributed remarkably to the expansion of indications, and this has been made possible by various advances in materials science. The induced pluripotent stem cell (iPS) cell technology for regenerating periodontal tissues, including alveolar bone, is expected to be applied in the treatment of diseases, such as tooth loss and periodontitis. This review focuses on the alveolar bone and describes clinical practice, techniques, and the latest basic research.

Evaluation of a novel sample preparation method for identifying Aspergillus fumigatus using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: Combining Yatalase and silica beads treatment.

Aspergillus spp. belong to filamentous fungi and sometimes cause invasive aspergillosis which has high mortality. Filamentous fungi are generally identified morphologically. However, morphologic identification is time consuming and requires advanced skills. It is difficult to train technicians and ensure a high level of quality. Therefore, an identification technique that is both accurate and relatively easy to learn is needed. In the present study, we focused on the effects of Yatalase and silica beads, which enable the efficient extraction of proteins via cell wall disruption of Aspergillus spp., and aimed to establish a novel sample preparation method using Yatalase and silica beads to enhance the efficiency of Aspergillus spp. identification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The sample preparation method using the combination of Yatalase and silica beads showed higher accuracy for the identification of Aspergillus spp. compared with Yatalase or silica beads alone. The Yatalase/silica beads method also resulted in significantly higher identification scores compared with the conventional method for the identification of Aspergillus fumigatus (n = 33). These findings indicate that our novel Yatalase/silica beads method provides more reliable identification of A. fumigatus than does the conventional method.

Metabolomics Research in Periodontal Disease by Mass Spectrometry.

Periodontology is a newer field relative to other areas of dentistry. Remarkable progress has been made in recent years in periodontology in terms of both research and clinical applications, with researchers worldwide now focusing on periodontology. With recent advances in mass spectrometry technology, metabolomics research is now widely conducted in various research fields. Metabolomics, which is also termed metabolomic analysis, is a technology that enables the comprehensive analysis of small-molecule metabolites in living organisms. With the development of metabolite analysis, methods using gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, capillary electrophoresis-mass spectrometry, etc. have progressed, making it possible to analyze a wider range of metabolites and to detect metabolites at lower concentrations. Metabolomics is widely used for research in the food, plant, microbial, and medical fields. This paper provides an introduction to metabolomic analysis and a review of the increasing applications of metabolomic analysis in periodontal disease research using mass spectrometry technology.

Development of a sensitive liquid chromatography-tandem mass spectrometry method for quantification of human plasma arginine vasopressin.

BACKGROUND AND AIMS: Direct measurement of arginine vasopressin (AVP) via immunoassays is not widely conducted, mainly because of technical constraints. Liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been widely used as the gold standard in clinical chemistry. Here, we aimed to develop an MS-based assay to determine human plasma AVP and compare the results with those obtained using a conventional immunoassay. MATERIALS AND METHODS: We developed a protocol using triple quadrupole MS coupled with LC for the measurement of human plasma AVP. Analytical evaluations of the method were performed, and the results obtained using LC/MS/MS and radioimmunoassay (RIA) were compared. RESULTS: The lower limit of quantification (LLOQ) for plasma AVP obtained using LC/MS/MS and RIA were 0.2 and 0.4 pg/mL, respectively. Although there was a weak overall correlation between the results obtained using the two different methods, the RIA results did not agree with the LC/MS/MS results, particularly at low concentrations. CONCLUSIONS: AVP detection through RIA is not satisfactory compared with that using LC/MS/MS. Diagnostic values of direct AVP measurements must be evaluated based on the results obtained via sensitive and accurate MS-based methods rather than those obtained through RIA.

Ubiquitination and Deubiquitination in Oral Disease.

Oral health is an integral part of the general health and well-being of individuals. The presence of oral disease is potentially indicative of a number of systemic diseases and may contribute to their early diagnosis and treatment. The ubiquitin (Ub) system has been shown to play a role in cellular immune response, cellular development, and programmed cell death. Ubiquitination is a post-translational modification that occurs in eukaryotes. Its mechanism involves a number of factors, including Ub-activating enzymes, Ub-conjugating enzymes, and Ub protein ligases. Deubiquitinating enzymes, which are proteases that reversely modify proteins by removing Ub or Ub-like molecules or remodeling Ub chains on target proteins, have recently been regarded as crucial regulators of ubiquitination-mediated degradation and are known to significantly affect cellular pathways, a number of biological processes, DNA damage response, and DNA repair pathways. Research has increasingly shown evidence of the relationship between ubiquitination, deubiquitination, and oral disease. This review investigates recent progress in discoveries in diseased oral sites and discusses the roles of ubiquitination and deubiquitination in oral disease.

Effect of humidity during sample preparation on bacterial identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a highly reliable and efficient technology for the identification of microbial pathogens. We previously found that 40% humidity was the optimal condition for the preparation of samples (co-crystallization of the sample and matrix) for serum peptidomic analysis via MALDI-TOF MS profiling. This optimum temperature was applied to obtain the highest reproducibility and throughput and greatest number of peaks. We therefore hypothesized that humidity control was also essential for MALDI-TOF MS bacterial identification. In this study, we constructed a simple sample preparation device that enables humidity control and used it for co-crystallization of the sample and matrix. Identification scores for five Gram-negative bacteria and six Gram-positive bacteria were determined using the MALDI BioTyper® system at three humidity ranges (10-20%, 30-40%, and 50-60%). As a result, higher identification scores were obtained at 30-40% humidity than at 10-20% or 50-60% humidity. At 30-40% humidity, 517/550 (94.0%) isolates scored greater than 2.0, indicating the success of species-level identification. Similarly, 537/550 (97.6%) isolates scored greater than 1.7, indicating the success of genus-level identification. Thus, 30-40% humidity generated optimal MALDI-TOF MS identification scores and the highest percentage of correct identifications. These results could lead to further improvements in the accuracy of MALDI-TOF MS bacterial identification.

Current Status of Matrix-Assisted Laser Desorption/Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) in Clinical Diagnostic Microbiology.

Mass spectrometry (MS), a core technology for proteomics and metabolomics, is currently being developed for clinical applications. The identification of microorganisms in clinical samples using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is a representative MS-based proteomics application that is relevant to daily clinical practice. This technology has the advantages of convenience, speed, and accuracy when compared with conventional biochemical methods. MALDI-TOF MS can shorten the time used for microbial identification by about 1 day in routine workflows. Sample preparation from microbial colonies has been improved, increasing the accuracy and speed of identification. MALDI-TOF MS is also used for testing blood, cerebrospinal fluid, and urine, because it can directly identify the microorganisms in these liquid samples without prior culture or subculture. Thus, MALDI-TOF MS has the potential to improve patient prognosis and decrease the length of hospitalization and is therefore currently considered an essential tool in clinical microbiology. Furthermore, MALDI-TOF MS is currently being combined with other technologies, such as flow cytometry, to expand the scope of clinical applications.

Proteome Analysis of Molecular Events in Oral Pathogenesis and Virus: A Review with a Particular Focus on Periodontitis.

Some systemic diseases are unquestionably related to periodontal health, as periodontal disease can be an extension or manifestation of the primary disease process. One example is spontaneous gingival bleeding, resulting from anticoagulant treatment for cardiac diseases. One important aspect of periodontal therapy is the care of patients with poorly controlled disease who require surgery, such as patients with uncontrolled diabetes. We reviewed research on biomarkers and molecular events for various diseases, as well as candidate markers of periodontal disease. Content of this review: (1) Introduction, (2) Periodontal disease, (3) Bacterial and viral pathogens associated with periodontal disease, (4) Stem cells in periodontal tissue, (5) Clinical applications of mass spectrometry using MALDI-TOF-MS and LC-MS/MS-based proteomic analyses, (6) Proteome analysis of molecular events in oral pathogenesis of virus in GCF, saliva, and other oral Components in periodontal disease, (7) Outlook for the future and (8) Conclusions. This review discusses proteome analysis of molecular events in the pathogenesis of oral diseases and viruses, and has a particular focus on periodontitis.

Mass spectrometry-based microbiological testing for blood stream infection.

BACKGROUND: The most successful application of mass spectrometry (MS) in laboratory medicine is identification (ID) of microorganisms using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in blood stream infection. We describe MALDI-TOF MS-based bacterial ID with particular emphasis on the methods so far developed to directly identify microorganisms from positive blood culture bottles with MALDI-TOF MS including our own protocols. We touch upon the increasing roles of Liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) as well. MAIN BODY: Because blood culture bottles contain a variety of nonbacterial proteins that may interfere with analysis and interpretation, appropriate pretreatments are prerequisites for successful ID. Pretreatments include purification of bacterial pellets and short-term subcultures to form microcolonies prior to MALDI-TOF MS analysis. Three commercial protocols are currently available: the Sepsityper® kit (Bruker Daltonics), the Vitek MS blood culture kit (bioMerieux, Inc.), and the rapid BACpro® II kit (Nittobo Medical Co., Tokyo). Because these commercially available kits are costly and bacterial ID rates using these kits are not satisfactory, particularly for Gram-positive bacteria, various home-brew protocols have been developed: 1. Stepwise differential sedimentation of blood cells and microorganisms, 2. Combination of centrifugation and lysis procedures, 3. Lysis-vacuum filtration, and 4. Centrifugation and membrane filtration technique (CMFT). We prospectively evaluated the performance of this CMFT protocol compared with that of Sepsityper® using 170 monomicrobial positive blood cultures. Although preliminary, the performance of the CMFT was significantly better than that of Sepsityper®, particularly for Gram-positive isolates. MALDI-TOF MS-based testing of polymicrobial blood specimens, however, is still challenging. Also, its contribution to assessment of susceptibility and resistance to antibiotics is still limited. For this purpose, liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) should be more useful because this approach can identify as many as several thousand peptide sequences. CONCLUSION: MALDI-TOF MS is now an essential tool for rapid bacterial ID of pathogens that cause blood stream infection. For the purpose of assessment of susceptibility and resistance to antibiotics of the pathogens, the roles of liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) will increase in the future.

An in-house centrifugation and membrane filtration technique for identifying microorganisms from positive blood culture bottles with high identification rates using matrix-assisted laser desorption ionization-Time-of-flight mass spectrometry: A preliminary report.

Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) is one of the most promising technologies for the identification of microbial pathogens directly from positive blood culture bottles. As blood culture bottle medium contains various nonbacterial proteins, including those derived from blood cells, pretreatment to effectively remove host cells is key for successful proteome-based identification of microorganisms. Although the Sepsityper® kit is the most widely used pretreatment protocol, its performance is not satisfactory, particularly for gram-positive isolates. We developed a new in-house protocol, the centrifugation and membrane filtration technique (CMFT), in which vacuum-filtration is coupled with differential centrifugation. We prospectively evaluated the performance of this novel method compared with that of the Sepsityper®. For gram-negative bacterial isolates, the species-level identification rates obtained with the CMFT and the Sepsityper® were comparable (98.8% vs 92.9%). By contrast, for gram-positive isolates, the performance of the CMFT was significantly better than that of the Sepsityper® (P < 0.05). Using our new protocol, 81 (95.3%) isolates were identified with a score >2.0, and 85 (100%) isolates were identified with a score >1.7, versus 46 (54.1%) and 69 (81.2%), respectively, for the Sepsityper®. These results are preliminary, but considering that this novel protocol provides notably high species-level identification rates for gram-positive isolates, it deserves assessment in a larger-scale study with a variety of platforms for MS-based identification of microorganisms.

A simple method for sequencing the whole human mitochondrial genome directly from samples and its application to genetic testing.

Next-generation sequencing (NGS) is a revolutionary sequencing technology for analyzing genomes. However, preprocessing methods for mitochondrial DNA (mtDNA) sequencing remain complex, and it is required to develop an authenticated preprocessing method. Here, we developed a simple and easy preprocessing method based on isothermal rolling circle mtDNA amplification using commercially available reagents. Isothermal amplification of mtDNA was successfully performed using both nanoliter quantities of plasma directly and 25 ng of total DNA extracted from blood or tissue samples. Prior to mtDNA amplification, it was necessary to treat the extracted total DNA with Exonuclease V, but it was not required to treat plasma. The NGS libraries generated from the amplified mtDNA provided sequencing coverage of the entire human mitochondrial genome. Furthermore, the sequencing results successfully detected heteroplasmy in patient samples, with called mutations and variants matching those from previous, independent, Sanger sequencing analysis. Additionally, a novel single nucleotide variant was detected in a healthy volunteer. The successful analysis of mtDNA using very small samples from patients is likely to be valuable in clinical medicine, as it could reduce patient discomfort by reducing sampling-associated damage to tissues. Overall, the simple and convenient preprocessing method described herein may facilitate the future development of NGS-based clinical and forensic mtDNA tests.

Current Status of Proteomic Technologies for Discovering and Identifying Gingival Crevicular Fluid Biomarkers for Periodontal Disease.

Periodontal disease is caused by bacteria in dental biofilms. To eliminate the bacteria, immune system cells release substances that inflame and damage the gums, periodontal ligament, or alveolar bone, leading to swollen bleeding gums, which is a sign of gingivitis. Damage from periodontal disease can cause teeth to loosen also. Studies have demonstrated the proteomic approach to be a promising tool for the discovery and identification of biochemical markers of periodontal diseases. Recently, many studies have applied expression proteomics to identify proteins whose expression levels are altered by disease. As a fluid lying in close proximity to the periodontal tissue, the gingival crevicular fluid (GCF) is the principal target in the search for periodontal disease biomarkers because its protein composition may reflect the disease pathophysiology. Biochemical marker analysis of GCF is effective for objective diagnosis in the early and advanced stages of periodontal disease. Periodontal diseases are also promising targets for proteomics, and several groups, including ours, have applied proteomics in the search for GCF biomarkers of periodontal diseases. This search is of continuing interest in the field of experimental and clinical periodontal disease research. In this article, we summarize the current situation of proteomic technologies to discover and identify GCF biomarkers for periodontal diseases.

Application of the biocopolymer preparation system, rapid BACpro® II kit, for mass-spectrometry-based bacterial identification from positive blood culture bottles by the MALDI Biotyper system.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used for identification of microorganisms from positive blood cultures. Pretreatments to effectively remove non-bacterial components and selectively collect microorganisms are a prerequisite for successful identification, and a variety of home-brew and commercial protocols have been reported. Although commercially available kits, mainly the Sepsityper Kit, are increasingly used, the identification rates reported often are not satisfactory, particularly for Gram-positive isolates. We recently developed a method to collect bacteria from positive blood culture bottles using a polyallylamine-polystyrene copolymer that has been used in wastewater processing. This pretreatment protocol is now commercially available as the rapid BACpro® II kit (Nittobo Medical Co., Tokyo, Japan). The operation time required for processing using this novel kit is approximately 10 min, and the entire procedure can be completed within a biosafety cabinet. Since the performance of the rapid BACpro® II kit has not been tested using the MALDI Biotyper system, we prospectively evaluated the performance of the rapid BACpro® II kit as compared with the Sepsityper® kit. Performance of the rapid BACpro® II kit was evaluated using a total of 193 monomicrobial cases of positive blood culture. Medium from blood culture bottles was pretreated by the rapid BACpro® II kit or the Sepsityper® Kit, and isolated cells were subjected to direct identification by MS fingerprinting in parallel with conventional subculturing for reference identification. The overall MALDI-TOF MS-based identification rates with >1.7 score and >2.0 score obtained using the rapid BACpro® II kit were 99.5% and 80.8%, respectively, whereas those obtained using the Sepsityper® Kit were 89.1% and 68.4%, respectively (P < 0.05 for >1.7 and P < 0.05 for >2.0 by Pearsons's chi-square). In Gram-positive cases, the rapid BACpro® II kit gave identification rate of 100% with >1.7 score and 69.4% with >2.0 score, whereas there were 84.7% and 56.8%, respectively by the Sepsityper® Kit (P < 0.05 for >1.7). These results are preliminary, but considering that this new kit is easy to perform and the identification rates are promising, the rapid BACpro® II kit deserves assessment in a larger-scale study with a variety of platforms for MS-based bacterial identification.

An improved in-house lysis-filtration protocol for bacterial identification from positive blood culture bottles with high identification rates by MALDI-TOF MS.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is now a well-established method for identification of microorganisms from positive blood cultures. Pretreatments to effectively remove non-bacterial proteins are a prerequisite for successful identification, and a variety of protocols have been reported. Although commercially available kits, mainly the Sepsityper Kit, are increasingly used, the identification rates reported often are not satisfactory, particularly for Gram-positive isolates. We developed a new, in-house lysis-filtration protocol and prospectively evaluated its performance compared to the Sepsityper kit. The in-house protocol consists of three simple steps: lysis by ammonium chloride, aspiration with a syringe fitted with a 0.45-µm membrane, and centrifugation to collect microbes. The novel protocol requires only 20 min. Performance of the in-house protocol was evaluated using a total of 117 monomicrobial cases of positive blood culture. Medium from blood culture bottles was pretreated by the in-house protocol or the commercial kit, and isolated cells were subjected to direct identification by mass spectrometry fingerprinting in parallel with conventional subculturing for reference identification. The overall MALDI-TOF MS-based identification rates with score > 1.7 and > 2.0 obtained using the in-house protocol were 99.2% and 85.5%, respectively, whereas those obtained using the Sepsityper Kit were 85.4% and 61.5%, respectively. For Gram-positive cases, the in-house protocol yielded scores >1.7 and > 2.0 at 98.5% and 76.1%, respectively, whereas the commercial kit yielded these scores at 76.1% and 43.3%, respectively. Although these are preliminary results, these values suggest that this easy lysis-filtration protocol deserves assessment in a larger-scale test.

Capsular serotyping of Haemophilus influenzae by using matrix-associated laser desorption ionization-time of flight mass spectrometry.

Haemophilus influenzae is a major pathogenic bacteria causing invasive disease, which is classified into six capsular serotypes (a-f) and non-typeable (NT) strains. Capsular serotyping of H. influenzae is traditionally determined by serological methods and more recently by PCR methods. However, these methods are time-consuming and expensive. In the present study, matrix-associated laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was evaluated as an alternative method for capsular serotyping of H. influenzae clinical strains. We created an in-house database of all six serotypes and NT H. influenzae strains using the main spectrum creation standard method set to the default parameters in MADI-TOF MS. We evaluated the performance of the in-house database using 79 clinical strains already identified by PCR and 58 prospectively collected clinical strains. Measurements were performed using the Bruker MALDI BioTyper system. The peak list was matched against the reference library using the integrated pattern algorithm of the software. The best-matched spectrum was considered the serotyping result. All 137 test strains were correctly identified as H. influenzae using MALDI-TOF MS. The sensitivity and specificity for identification for type b, type e, and type f capsular serotypes and NT H. influenzae using MALDI-TOF MS were 100%/94.3%, 94.7%/97.9%, 97.4%/97.9%, and 85.5%/99.2%, respectively. Our findings indicate that MALDI-TOF MS is a useful alternative method for capsular serotyping of H. influenzae strains. This method is faster and more cost-effective than traditional methods and will therefore be useful for routine applications in clinical laboratories.

Assessment by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry of the Effects of Preanalytical Variables on Serum Peptidome Profiles Following Long-Term Sample Storage.

PURPOSE: Human serum and plasma are often used as clinical specimens in proteomics analyses, and peptidome profiling of human serum is a promising tool for identifying novel disease-associated biomarkers. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used for peptidomic biomarker discovery. Careful sample collection and handling are required as either can have a profound impact on serum peptidome patterns, yet the effects of preanalytical variables on serum peptidome profiles have not been completely elucidated. The present study investigated the effects of preanalytical variables, including storage temperature, duration (up to 12 months), and thawing methods, on MALDI-TOF MS-based serum peptidome patterns. EXPERIMENTAL DESIGN: Aliquots of serum samples were pretreated with weak cation exchanger magnetic beads using an automated ClinProtRobot system and then analyzed by MALDI-TOF MS. RESULTS: A number of significant differences in peak intensities were observed depending on sample processing variables. CONCLUSIONS AND CLINICAL RELEVANCE: These peaks can be used as sample quality markers to assess the effects of long-term storage on serum peptidome profiles using MALDI-TOF MS.

Ubiquitination in Periodontal Disease: A Review.

Periodontal disease (periodontitis) is a chronic inflammatory condition initiated by microbial infection that leads to gingival tissue destruction and alveolar bone resorption. The periodontal tissue's response to dental plaque is characterized by the accumulation of polymorphonuclear leukocytes, macrophages, and lymphocytes, all of which release inflammatory mediators and cytokines to orchestrate the immunopathogenesis of periodontal disease. Ubiquitination is achieved by a mechanism that involves a number of factors, including an ubiquitin-activating enzyme, ubiquitin-conjugating enzyme, and ubiquitin-protein ligase. Ubiquitination is a post-translational modification restricted to eukaryotes that are involved in essential host processes. The ubiquitin system has been implicated in the immune response, development, and programmed cell death. Increasing numbers of recent reports have provided evidence that many approaches are delivering promising reports for discovering the relationship between ubiquitination and periodontal disease. The scope of this review was to investigate recent progress in the discovery of ubiquitinated protein in diseased periodontium and to discuss the ubiquitination process in periodontal diseases.