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1.
Phys Rev Lett ; 129(2): 021803, 2022 Jul 08.
Article in English | MEDLINE | ID: mdl-35867435

ABSTRACT

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, probes nuclear effects that govern neutrino-nucleus interactions. This Letter reports the first measurement of the triple-differential cross section for ν_{µ} quasielastic-like reactions using the hydrocarbon medium of the MINERvA detector exposed to a wideband beam spanning 2≤E_{ν}≤20 GeV. The measurement maps the correlations among transverse and longitudinal muon momenta and summed proton kinetic energies, and compares them to predictions from a state-of-art simulation. Discrepancies are observed that likely reflect shortfalls with modeling of pion and nucleon intranuclear scattering and/or spectator nucleon ejection from struck nuclei. The separate determination of leptonic and hadronic variables can inform experimental approaches to neutrino-energy estimation.

2.
Naturwissenschaften ; 108(1): 2, 2020 Dec 11.
Article in English | MEDLINE | ID: mdl-33306163

ABSTRACT

Myxodiaspory (formation of mucilage envelope around seeds and fruits) is a common adaptation to dry habitats known in many families of Angiosperms. The mucilage envelope of some seeds seems to be also a unique morphological adaptation which protects myxospermatic diaspores while passing through the bird's digestive system. To evaluate the protective potential of mucilage, we fed the diaspores of seven plant species (representing three different mucilage types and three species of non-mucilaginous plants) to pigeons, Columba livia domestica. Twenty-four hours later, we collected the droppings of pigeons and examined a total of 18,900 non-destroyed diaspores to check for mucilage presence and germination ability. Out of all the examined diaspores, 4.5% were mucilaginous seeds. Among them, the highest number (12.2-13.5%) of viable diaspores belonged to the hemicellulosic type of mucilage (from Plantago species). Only 3.7% of germinating diaspores with pectic mucilage (Linum usitatissimum) were collected, and no seeds representing cellulosic mucilage (e.g., Ocimum basilicum). For non-mucilaginous plants, we collected only a few individual seeds (0.1% out of 8100 seeds used). We noted that the mucilaginous seeds found in the droppings were able to germinate; however, the germination ability was generally smaller in comparison to the control (i.e., not digested) seeds. Our results revealed that the presence of mucilage envelope has an impact on diaspore dispersal and survivability. With our experiments, we demonstrated for the first time that the mucilage envelope, especially of the non-cellulosic type, supports endozoochory. We also showed that non-mucilaginous seeds can be occasionally dispersed via endozoochory and are able to germinate. The results of our studies can explain the ways of plants distribution at a small, local scale as well as in long-distance dispersal, e.g., between islands or even continents.


Subject(s)
Germination/physiology , Plant Mucilage/metabolism , Plant Physiological Phenomena , Seeds/growth & development , Animals , Columbidae/metabolism , Fruit/metabolism , Gastrointestinal Tract/metabolism , Plant Mucilage/chemistry , Plants , Seeds/chemistry
3.
Orthopade ; 45(2): 167-73, 2016 Feb.
Article in German | MEDLINE | ID: mdl-26432792

ABSTRACT

BACKGROUND: Due to current and prospective demographic developments, the provision of high-quality medical care is not guaranteed in Germany. OBJECTIVES: The aim of this study is to analyze the utilization of medical service providers for diseases related to orthopedic/trauma surgery and deduce the corresponding number of medical service providers until 2050. MATERIALS AND METHODS: Data provided by the Statistical Offices of the Federal Republic and the Federal States and the Scientific Institute of the AOK (2008-2012) were used to analyze the utilization behavior of four pre-determined orthopedic/trauma surgery disease groups (osteoarthritis, back pain, osteoporosis, trauma). Routine data of the current (2012) health care provision delivered by the compulsory health insurances (GKV) are the basis of the prognosis. Using population projections from the Federal Statistical Office, the health care demand until 2050 was predicted and using statistics from the German Medical Association, the number of required health care providers was determined. RESULTS: An increase in physician consultations until 2040 is expected for osteoarthritis (+ 21 %), osteoporosis (26 %), and trauma (+ 13 %). From 2040-2050 the health care utilization behavior of all examined diseases is expected to decrease. The increasing health care usage behavior until 2040 is associated with an increase in health care providers. CONCLUSIONS: Until 2030 a significant increase in the burden of orthopedic/trauma surgery diseases is expected. In 2050 the level of health care needs will be equivalent to that in 2030. Comprehensive needs assessment and planning are needed in order to create health care provision structures and processes that address potential changes in utilization behavior.


Subject(s)
Bone Diseases/surgery , Fractures, Bone/rehabilitation , Health Workforce/statistics & numerical data , Needs Assessment , Orthopedic Procedures/statistics & numerical data , Orthopedic Surgeons/supply & distribution , Adolescent , Adult , Aged , Aged, 80 and over , Bone Diseases/epidemiology , Child , Child, Preschool , Female , Fractures, Bone/epidemiology , Germany/epidemiology , Health Services Accessibility/statistics & numerical data , Health Services Accessibility/trends , Health Workforce/trends , Humans , Infant , Infant, Newborn , Male , Middle Aged , Orthopedic Surgeons/trends , Prevalence , Utilization Review , Young Adult
4.
Orthopade ; 44(4): 261-4, 266-8, 2015 Apr.
Article in German | MEDLINE | ID: mdl-25854188

ABSTRACT

BACKGROUND: Arthroplasty is an effective treatment for end-stage osteoarthritis of the knee and is one of Germany's most frequently performed orthopedic procedures. DISCUSSION: However, a considerable number of patient are not satisfied with the results after knee arthroplasty. The patient's perspective is particularly important for shared decision making. "Patient satisfaction" with the surgery is an expression of the patient's perspective, but might not be sufficient as the only outcome measure. There is no international consensus which outcome measures should be used after knee arthroplasty. CONCLUSION: Therefore, different measurement tools are used for the acquisition of a variety of outcome measures in order to quantify the results of knee arthroplasty. These tools should be used according to their reliability, validity, and responsiveness. This article provides an overview about available measurement tools.


Subject(s)
Arthroplasty, Replacement, Knee/methods , Arthroplasty, Replacement, Knee/psychology , Outcome Assessment, Health Care/methods , Patient Satisfaction , Psychometrics/methods , Quality of Life/psychology , Germany , Humans , Reproducibility of Results , Sensitivity and Specificity , Severity of Illness Index , Sickness Impact Profile
5.
Orthopade ; 44(7): 555-65, 2015 Jul.
Article in German | MEDLINE | ID: mdl-25925089

ABSTRACT

BACKGROUND: Concomitant disorders at the time of surgery in addition to psychological and socioeconomic patient characteristics may influence treatment outcomes in hip arthroplasty. OBJECTIVES: To describe the impact of these factors on perioperative complications and postoperative results in terms of function, quality of life, and patient satisfaction. MATERIALS AND METHODS: Review of relevant clinical studies, meta-analyses, and presentation of our own results. RESULTS: Comorbidities in general, especially in combination, increase the perioperative risk profile. Socioeconomic factors (education, professional qualifications, social deprivation) in addition to psychological variables (depression, distressed personality) can have a major impact on postoperative functional outcomes and patient satisfaction. CONCLUSIONS: It is of crucial importance to avoid inequalities in the provision of joint replacement for patients with hip osteoarthritis and co-existing risk factors. Preventive strategies should be implemented to reduce the negative impact of comorbidities on treatment outcome. Personalized communication and education may be helpful in avoiding unrealistic patient expectations before hip replacement.


Subject(s)
Arthroplasty, Replacement, Hip/psychology , Depression/psychology , Mental Disorders/psychology , Osteoarthritis, Hip/psychology , Osteoarthritis, Hip/therapy , Patient Acceptance of Health Care/psychology , Comorbidity , Depression/complications , Humans , Mental Disorders/complications , Osteoarthritis, Hip/complications , Physician-Patient Relations , Risk Factors
6.
Curr Oncol ; 22(2): e100-12, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25908915

ABSTRACT

To meet the needs of patients, Canadian surgical and medical oncology leaders in the treatment of peritoneal surface malignancies (psms), together with patient representatives, formed the Canadian HIPEC Collaborative Group (chicg). The group is dedicated to standardizing and improving the treatment of psm in Canada so that access to treatment and, ultimately, the prognosis of Canadian patients with psm are improved. Patients with resectable psm arising from colorectal or appendiceal neoplasms should be reviewed by a multidisciplinary team including surgeons and medical oncologists with experience in treating patients with psm. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy should be offered to appropriately selected patients and performed at experienced centres. The aim of this publication is to present guidelines that we recommend be applied across the country for the treatment of psm.

7.
J Nanosci Nanotechnol ; 11(10): 8450-6, 2011 Oct.
Article in English | MEDLINE | ID: mdl-22400208

ABSTRACT

Aggregatibacter actinomycetemcomitans is a gram-negative periodontopathogen found within the subgingival plaque on the tooth surface. It is associated with localized aggressive periodontitis, a severe form of periodontitis in adolescents, and is the cause various extra-oral infections. The ability of this organism to tenaciously adhere to abiotic surfaces has been attributed to bundle-forming type IVb-like fimbriae whose major component is the fimbrial lower molecular weight protein (Flp). In this study the adhesion of purified Flp fimbriae isolated from A. actinomycetemcomitans to materials with different surface chemistries was measured using atomic force microscopy (AFM). The adhesion of Flp fimbriae to uncoated and saliva-coated tooth, hydroxylapatite, and glass surfaces was compared. Force data were used to quantify the magnitude of adhesion of the fimbriae and force-distance profiles were used to predict the mechanisms of adhesion. The results of this study confirm that non-specific interactions likely dominate the adhesion of these fimbriae to the surfaces used in this study. However, force data indicate that non-specific electrostatic interactions may be more significant under the conditions used in this study. Salivary coatings did affect both the hydrophobicity and adhesion of these fimbriae to the surfaces used in this study. Additionally, these data demonstrate the affect of salivary proteins on bacterial adhesion in the oral cavity.


Subject(s)
Aggregatibacter actinomycetemcomitans/physiology , Bacterial Adhesion/physiology , Actinobacillus Infections/microbiology , Aggregatibacter actinomycetemcomitans/metabolism , Bacterial Proteins/physiology , Fimbriae, Bacterial/physiology , Glass , Humans , Male , Microscopy, Atomic Force/methods , Mouth/microbiology , Periodontitis/metabolism , Saliva/microbiology , Salivary Proteins and Peptides/metabolism , Surface Properties , Tooth/microbiology
8.
Br Poult Sci ; 52(2): 173-6, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21491240

ABSTRACT

1. A 525-bp fragment of a feather keratin (F-KER) gene was amplified. Four PCR products were sequenced. 2. Two substitutions in the amplified region were observed, one of them in the coding region of the gene (cysteine to glycine substitution in the protein). A new ACRS-PCR test for AvaI enzyme was designed. A total of 344 domestic pigeons (Columba livia var. domestica) were genotyped. 3. There were significant differences in the frequencies of alleles and genotypes between homing and non-homing pigeons. The frequency of the rare F-KER(G) allele was higher in the group of homing pigeons. 4. The effects of the detected polymorphism on flying performance should be verified in biomechanical studies.


Subject(s)
Avian Proteins/genetics , Columbidae/genetics , Feathers/metabolism , Keratins/genetics , Polymorphism, Genetic , Animals , DNA Fragmentation , Gene Frequency , Sequence Analysis, DNA
9.
Curr Oncol ; 27(6): e621-e631, 2020 12.
Article in English | MEDLINE | ID: mdl-33380878

ABSTRACT

Modern management of colorectal cancer (crc) with peritoneal metastasis (pm) is based on a combination of cytoreductive surgery (crs), systemic chemotherapy, and hyperthermic intraperitoneal chemotherapy (hipec). Although the role of hipec has recently been questioned with respect to results from the prodige 7 trial, the role and benefit of a complete crs were confirmed, as observed with a 41-month gain in median survival in that study, and 15% of patients remaining disease-free at 5 years. Still, crc with pm is associated with a poor prognosis, and good patient selection is essential. Many questions about the optimal management approach for such patients remain, but all patients with pm from crc should be referred to, or discussed with, a pm surgical oncologist, because cure is possible. The objective of the present guideline is to offer a practical approach to the management of pm from crc and to reflect on the new practice standards set by recent publications on the topic.


Subject(s)
Colorectal Neoplasms , Hyperthermia, Induced , Peritoneal Neoplasms , Canada , Colorectal Neoplasms/therapy , Cytoreduction Surgical Procedures , Humans , Peritoneal Neoplasms/therapy
10.
Mol Oral Microbiol ; 32(4): 275-287, 2017 08.
Article in English | MEDLINE | ID: mdl-27448788

ABSTRACT

Periodontitis is a highly prevalent disease caused in part by an aberrant host response to the oral multi-species biofilm. A balance between the oral bacteria and host immunity is essential for oral health. Imbalances in the oral microbiome lead to an uncontrolled host inflammatory response and subsequent periodontal disease (i.e. gingivitis and periodontitis). TREM-1 is a signaling receptor present on myeloid cells capable of acting synergistically with other pattern recognition receptors leading to amplification of inflammatory responses. The aim of this study was to investigate the activation of the TREM-1 pathway in the human monocyte-like cell line THP-1 exposed to both oral pathogens and commensals. The relative expression of the genes encoding TREM-1 and its adapter protein DAP12 were determined by quantitative real-time polymerase chain reaction. The surface expression of TREM-1 was determined by flow cytometry. Soluble TREM-1 and cytokines were measured by enzyme-linked immunosorbent assay. The results demonstrate that both commensal and pathogenic oral bacteria activate the TREM-1 pathway, resulting in a proinflammatory TREM-1 activity-dependent increase in proinflammatory cytokine production.


Subject(s)
Bacteria/immunology , Bacteria/pathogenicity , Monocytes/microbiology , Periodontal Diseases/immunology , Triggering Receptor Expressed on Myeloid Cells-1/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Cells, Cultured , Cytokines/genetics , Flow Cytometry , Humans , Immunity, Innate , Membrane Proteins/genetics , Membrane Proteins/metabolism , Periodontal Diseases/microbiology , Porphyromonas gingivalis/immunology , Porphyromonas gingivalis/pathogenicity , Real-Time Polymerase Chain Reaction , Signal Transduction , Streptococcus gordonii/immunology , Streptococcus gordonii/pathogenicity , Symbiosis , THP-1 Cells , Triggering Receptor Expressed on Myeloid Cells-1/genetics
11.
J Appl Physiol (1985) ; 72(4): 1247-54, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1592711

ABSTRACT

We evaluated the effects of four standard anesthetization regimens on the systemic cardiovascular responses to bilateral common carotid artery occlusion in 28 adult male rats. Rats were randomly assigned to anesthesia groups: thiopental sodium (PT; 100 mg/kg ip), alpha-chloralose (CH; 100 mg/kg iv), ketamine hydrochloride plus acepromazine (KA; 135 mg/kg and 1.5 mg/kg sc), and pentobarbital sodium (PB; 50 mg/kg ip). PT and PB animals had similar baseline heart rates (HR; 333 and 345 beats/min, respectively) and arterial pressures (MAP; 126 and 118 mmHg, respectively), whereas both were lower in CH and KA (314 and 288 beats/min, 92 and 85 mmHg). During bilateral carotid occlusion, PT demonstrated the largest change in MAP (dMAP; +27 mmHg) but the smallest change in HR (dHR; +8 beats/min). CH and PB demonstrated similar dHR (+24 and +16 beats/min) and dMAP (+20 and +19 mmHg). KA demonstrated a significant dHR (+14 beats/min), but the average dMAP was not statistically significant (+3 mmHg). Therefore, carotid occlusion in rats anesthetized with PT, PB, or CH consistently elicits a systemic arterial pressor response comparable with that reported for conscious animals. When the magnitude and stability of baseline HR and MAP are also considered, PT and PB anesthetization seem to be the most reliable for evaluation of the carotid occlusion pressor response in rats.


Subject(s)
Anesthetics/pharmacology , Carotid Arteries/physiology , Hemodynamics/drug effects , Animals , Blood Pressure/drug effects , Constriction , Denervation , Evaluation Studies as Topic , Heart Rate/drug effects , Hemodynamics/physiology , Male , Pressoreceptors/drug effects , Rats , Rats, Inbred Strains , Reflex/drug effects
12.
Brain Res ; 747(1): 140-3, 1997 Jan 30.
Article in English | MEDLINE | ID: mdl-9042537

ABSTRACT

A retrograde neuronal tracer (Fast Blue) was injected in the cervical end of the uterine horn of virgin rats. The majority of the retrogradely labeled post-ganglionic sympathetic neurons were found in the sympathetic chain (74%). The superior mesenteric ganglia, inferior mesenteric ganglia and suprarenal ganglia accounted for 22, 3 and < 1%, respectively. The distribution of neurons in the sympathetic chain labeled from the uterus resembles that described for other pelvic organs.


Subject(s)
Sympathetic Nervous System/physiology , Uterus/innervation , Animals , Cervix Uteri/innervation , Female , Ganglia, Sympathetic/cytology , Ganglia, Sympathetic/physiology , Histocytochemistry , Rats , Rats, Sprague-Dawley , Sympathetic Fibers, Postganglionic/physiology , Sympathetic Nervous System/cytology
13.
Mutat Res ; 346(4): 207-14, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7753113

ABSTRACT

We have molecularly characterized the SNG1 gene that confers hyper-resistance to the mutagen N-methyl-N'nitro-N-nitrosoguanidine (MNNG) in Saccharomyces cerevisiae when overexpressed on a multi-copy plasmid. This hyper-resistance to MNNG is not due to depletion of glutathione pools since multi-copy SNG1 containing yeast transformants contain at least wild type levels of glutathione; DNA repair seems unaffected in these transformants as the multi-copy SNG1-mediated MNNG hyper-resistance is also seen in DNA repair mutants belonging to each of the three epistasis groups of yeast repair mutants. It could be shown that SNG1 is not under control of the YAP1 encoded transcription activator that controls expression of at least two genes involved in MNNG metabolism in yeast. sng1 null mutants are viable but exhibit only slight sensitivity to MNNG, indicating that SNG1 does not encode a protein involved in a major detoxification step of this mutagen. Sequencing of the HYR-mediating passenger DNA revealed that SNG1 encodes a 547 a polypeptide containing seven transmembrane-spanning regions that may be membrane-bound. Comparison of the DNA sequence with established gene databanks revealed that SNG1 is a novel yeast gene.


Subject(s)
Fungal Proteins/genetics , Genes, Fungal/genetics , Membrane Proteins/genetics , Methylnitronitrosoguanidine/pharmacology , Mutagens/pharmacology , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae/genetics , Amino Acid Sequence , Cloning, Molecular , DNA Repair/genetics , DNA-Binding Proteins/genetics , Drug Resistance, Microbial/genetics , Epistasis, Genetic , Escherichia coli/genetics , Glutathione/analysis , Molecular Sequence Data , Mutagenesis, Insertional , Restriction Mapping , Sequence Analysis, DNA , Transcription Factors/genetics
14.
Arch Oral Biol ; 46(4): 323-33, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11269866

ABSTRACT

The significance of Streptococcus gordonii in dental caries is undefined, as is that of other alpha-amylase-binding bacteria (ABB) commonly found in the mouth. To clarify the ecological and cariological roles of S. gordonii our specific pathogen-free Osborne-Mendel rats, TAN:SPFOM(OM)BR, were fed either diet 2000 (containing 56% confectioner's sugar, most of which is sucrose) or diet 2000CS (containing 56% cornstarch, in lieu of confectioner's sugar) and inoculated with S. gordonii strains. Uninoculated rats were free of both indigenous mutans streptococci (MS) and ABB, including S. gordonii, as shown by culture on mitis salivarius and blood agars of swabs and sonicates of dentitions after weanlings had consumed these diets for 26 days. ABB were detected by radiochemical assay using [125I]-amylase reactive to alpha-amylase-binding protein characteristic of the surface of S. gordonii and other ABB. No ABB were detected (detection limit < 1 colony-forming units in 10(6) colony-forming units). Thus the TAN:SPFOM(OM)BR colony presents a 'clean animal model' for subsequent study. Consequently, S. gordonii strains Challis or G9B were used to inoculate weanling rat groups consuming either the high-sucrose diet 2000 or the cornstarch diet 2000CS. Two additional groups fed each of these diets remained unioculated. Recoveries of inoculants were tested 12 and 26 days later by oral swabs and sonication of the molars of one hemimandible of each animal, respectively. Uninoculated animals were reconfirmed to be free of ABB and mutans streptococci, but inoculated ones eating diet 2000CS had S. gordonii recoveries of 1-10% or, if eating diet 2000, 10-30% of total colony-farming units in sonicates. There were no statistically significant differences among the inoculated and uninoculated animal groups' caries scores when they ate the cornstarch diet. Lesion scores for sucrose-eating rats were, however, from 2.4-5.1-fold higher than for cornstarch-eating rats, P < 0.001, and were still higher if animals had been inoculated with either Challis (1.41-fold) or G9B (1.64-fold), than if uninoculated, both P < 0.001, so long as the rats ate the sucrose diet. Therefore, TAN:SPFOM(OM)BR rats do not harbour ABB or S. gordonii but can be colonized by S. gordonii. Colonization levels of S. gordonii on the teeth are higher in the presence of high sucrose than with high starch-containing diets. Caries scores are augmented by sucrose compared with starch, and are further augmented by S gordonii colonization. S. gordonii is thus cariologically significant in the presence of sucrose, at least in this rat.


Subject(s)
Dental Caries/microbiology , Disease Models, Animal , Rats, Inbred Strains/microbiology , Streptococcus sanguis/enzymology , Streptococcus sanguis/pathogenicity , Amylases/metabolism , Analysis of Variance , Animal Feed , Animals , Dietary Sucrose/metabolism , Mouth/microbiology , Protein Binding , Rats , Specific Pathogen-Free Organisms , Starch/metabolism , Statistics, Nonparametric , Virulence
15.
Eur J Surg Oncol ; 40(6): 739-46, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24246611

ABSTRACT

BACKGROUND: The role of curative-intent surgery for retroperitoneal recurrence (RPR) of colorectal cancer (CRC) remains controversial. We previously showed 0% mortality and acceptable morbidity in patients who underwent resection of RPR.(1) Here we examine long-term overall and disease-free survival (OS, DFS). METHODS: We identified patients who underwent resection for RPR of CRC between 01/1999 and 02/2010 from two prospective CRC databases. RESULTS: The study cohort was composed of 48 patients (26 women) whose median age was 60 (36-80) years. Eleven patients had previously undergone resection of a different focus of disease recurrence, and 8 patients had additional site(s) of distant metastatic disease at the time of RPR resection. Following surgery for RPR, 5 patients were left with gross residual disease, and 6 had microscopically positive margins. Median follow-up was 32 (3-127) months. At last follow-up, 13 patients had died of cancer and 1 of other causes. For the entire cohort of 48 patients, 5-year OS was 70% (median 80 mo). In univariate analysis, OS was reduced in younger patients (p = 0.003) and in those with gross residual disease (p = 0.033). In patients who had grossly complete resection, 5-year DFS was 49% (median 38 mo). Predictors of reduced DFS on multivariable analysis were young age and R1 resection. CONCLUSION: OS and DFS after resection of RPR in well-selected patients were favorable. Patients with RPR of CRC should be considered for curative-intent surgery with careful discussion at multidisciplinary cancer conference.


Subject(s)
Colorectal Neoplasms/surgery , Neoplasm Recurrence, Local/surgery , Retroperitoneal Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Colorectal Neoplasms/pathology , Female , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/pathology , Reoperation/statistics & numerical data , Retroperitoneal Neoplasms/pathology , Retrospective Studies , Survival Rate , Treatment Outcome
16.
Mol Oral Microbiol ; 27(4): 284-94, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22759313

ABSTRACT

Streptococcus gordonii is a common oral commensal bacterial species in tooth biofilm (dental plaque) and specifically binds to salivary amylase through the surface exposed amylase-binding protein A (AbpA). When S. gordonii cells are pretreated with amylase, amylase bound to AbpA facilitates growth with starch as a primary nutrition source. The goal of this study was to explore possible regulatory effects of starch, starch metabolites and amylase on the expression of S. gordonii AbpA. An amylase ligand-binding assay was used to assess the expression of AbpA in culture supernatants and on bacterial cells from S. gordonii grown in defined medium supplemented with 1% starch, 0.5 mg ml(-1) amylase, with starch and amylase together, or with various linear malto-oligosaccharides. Transcription of abpA was determined by reverse transcription quantitative polymerase chain reaction. AbpA was not detectable in culture supernatants containing either starch alone or amylase alone. In contrast, the amount of AbpA was notably increased when starch and amylase were both present in the medium. The expression of abpA was significantly increased (P < 0.05) following 40 min of incubation in defined medium supplemented with starch and amylase. Similar results were obtained in the presence of maltose and other short-chain malto-oligosacchrides. These results suggest that the products of starch hydrolysis produced from the action of salivary α-amylase, particularly maltose and maltotriose, up-regulate AbpA expression in S. gordonii.


Subject(s)
Amylases/metabolism , Bacterial Outer Membrane Proteins/genetics , Gene Expression Regulation, Enzymologic , Starch/metabolism , Streptococcus gordonii/enzymology , Bacterial Outer Membrane Proteins/biosynthesis , Enzyme Induction , Humans , Hydrolysis , Maltose/physiology , Polysaccharides/physiology , Saliva/enzymology
17.
Mol Oral Microbiol ; 27(5): 327-49, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22958383

ABSTRACT

Iron can regulate biofilm formation via non-coding small RNA (sRNA). To determine if iron-regulated sRNAs are involved in biofilm formation by the periodontopathogen Aggregatibacter actinomycetemcomitans, total RNA was isolated from bacteria cultured with iron supplementation or chelation. Transcriptional analysis demonstrated that the expression of four sRNA molecules (JA01-JA04) identified by bioinformatics was significantly upregulated in iron-limited medium compared with iron-rich medium. A DNA fragment encoding each sRNA promoter was able to titrate Escherichia coli ferric uptake regulator (Fur) from a Fur-repressible reporter fusion in an iron uptake regulator titration assay. Cell lysates containing recombinant AaFur shifted the mobility of sRNA-specific DNAs in a gel shift assay. Potential targets of these sRNAs, determined in silico, included genes involved in biofilm formation. The A. actinomycetemcomitans overexpressing JA03 sRNA maintained a rough phenotype on agar, but no longer adhered to uncoated polystyrene or glass, although biofilm determinant gene expression was only modestly decreased. In summary, these sRNAs have the ability to modulate biofilm formation, but their functional target genes remain to be confirmed.


Subject(s)
Aggregatibacter actinomycetemcomitans/genetics , Bacterial Proteins/metabolism , Iron/metabolism , Metalloproteins/metabolism , RNA, Bacterial/genetics , RNA, Small Untranslated/genetics , Repressor Proteins/metabolism , Trans-Activators/metabolism , Bacterial Adhesion/genetics , Bacterial Proteins/genetics , Biofilms/growth & development , Consensus Sequence/genetics , Gene Expression Regulation, Bacterial/genetics , Genes, Reporter/genetics , Humans , Mutation/genetics , Phenotype , Plasmids/genetics , Repressor Proteins/genetics , Transcription, Genetic/genetics , Up-Regulation
18.
J Dent Res ; 91(5): 513-9, 2012 May.
Article in English | MEDLINE | ID: mdl-22431892

ABSTRACT

Streptococcus gordonii and Streptococcus mutans avidly colonize teeth. S. gordonii glucosyltransferase (GtfG) and amylase-binding proteins (AbpA/AbpB), and S. mutans glucosyltransferase (GtfB), affect their respective oral colonization abilities. We investigated their interrelationships and caries association in a rat model of human caries, examining the sequence of colonization and non- vs. high-sucrose diets, the latter being associated with aggressive decay in humans and rats. Virulence-characterized wild-types of both species and well-defined mutants of S. gordonii with interrupted abpA and gtfG genes were studied. While both S. gordonii and S. mutans were abundant colonizers of rat's teeth in the presence of either diet, if inoculated singly, S. mutans always out-competed S. gordonii on the teeth, independent of diet, strain of S. mutans, simultaneous or sequential inoculation, or presence/absence of mutations of S. gordonii's abpA and gtfG genes known to negatively or positively affect its colonization and to interact in vitro with S. mutans GtfB. S. mutans out-competed S. gordonii in in vivo plaque biofilm. Caries induction reflected S. mutans or S. gordonii colonization abundance: the former highly cariogenic, the latter not. S. gordonii does not appear to be a good candidate for replacement therapy. These results are consistent with human data.


Subject(s)
Dental Caries/microbiology , Dental Plaque/microbiology , Streptococcus gordonii/physiology , Streptococcus mutans/physiology , Animals , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/genetics , Dietary Sucrose/metabolism , Disease Models, Animal , Glucosyltransferases/genetics , Microbial Interactions/genetics , Rats , Virulence Factors/genetics
19.
Mol Oral Microbiol ; 25(2): 150-6, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20331802

ABSTRACT

A substantial proportion of the streptococcal species found in dental plaque biofilms are able to interact with the abundant salivary enzyme alpha-amylase. These streptococci produce proteins that specifically bind amylase. An important plaque species, Streptococcus mitis, secretes a 36-kDa amylase-binding protein into the extracellular milieu. Proteins precipitated from S. mitis NS51 cell culture supernatant by the addition of purified salivary amylase were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to a membrane, and a prominent 36-kDa band was cut from the membrane and sequenced to yield the N-terminal amino acid sequence DSQAQYSNGV. Searching the S. mitis genome sequence database revealed a single open reading frame containing this sequence, and the gene was amplified by the S. mitis genomic DNA polymerase chain reaction. The coding region of this open reading frame, designated amylase-binding protein C (AbpC), was cloned into an Escherichia coli expression vector and the recombinant AbpC (rAbpC) was purified from the soluble fraction of the E. coli cell lysate. Purified AbpC was found to interact with immobilized amylase, confirming AbpC as a new streptococcal amylase-binding protein.


Subject(s)
Bacterial Outer Membrane Proteins/genetics , Bacterial Outer Membrane Proteins/isolation & purification , Streptococcus mitis/enzymology , alpha-Amylases/metabolism , Amino Acid Sequence , DNA, Bacterial/analysis , Dental Plaque/microbiology , Electrophoresis, Polyacrylamide Gel , Escherichia coli/metabolism , Humans , Protein Binding , Recombinant Proteins/isolation & purification , Saliva/microbiology , Streptococcus mitis/genetics , Transfection
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