Simultaneous Measurement of Proton and Lepton Kinematics in Quasielasticlike ν_{µ}-Hydrocarbon Interactions from 2 to 20 GeV.

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.

The role of mucilage envelope in the endozoochory of selected plant taxa.

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.

Canadian guidelines on the management of colorectal peritoneal metastases.

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.

Activation of the TREM-1 pathway in human monocytes by periodontal pathogens and oral commensal bacteria.

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.

[Orthopaedic and trauma surgical care until 2050. Analysis of the utilization behavior for relevant diseases and derivation of the number of medical service providers]. / Orthopädisch-unfallchirurgische Versorgung bis 2050. Analyse des Inanspruchnahmeverhaltens bei relevanten Erkrankungen und Ableitung der Häufigkeit ärztlicher Leistungserbringer.

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.

[Personality and comorbidity: are there "difficult patients" in hip arthroplasty?]. / Persönlichkeitsprofil und Komorbidität: Gibt es den "schwierigen Patienten" in der primären Hüftendoprothetik?

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.

[Objectifying results in total knee arthroplasty: Is "patient satisfaction" adequate]. / Ergebnisobjektivierung bei Knietotalendoprothesen : Reicht die "Patientenzufriedenheit"?

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.

Guidelines on the use of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in patients with peritoneal surface malignancy arising from colorectal or appendiceal neoplasms.

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.

Long-term outcomes following resection of retroperitoneal recurrence of colorectal cancer.

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.

Novel iron-regulated and Fur-regulated small regulatory RNAs in Aggregatibacter actinomycetemcomitans.

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.

Effect of starch and amylase on the expression of amylase-binding protein A in Streptococcus gordonii.

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.

Streptococcus mutans out-competes Streptococcus gordonii in vivo.

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.

Feather keratin gene polymorphism (F-KER) in domestic pigeons.

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.

Atomic force spectroscopy evidence of non-specific adhesion of Aggregatibacter actinomycetemcomitans.

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.

Identification and characterization of amylase-binding protein C from Streptococcus mitis NS51.

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.

Amylase-binding proteins A (AbpA) and B (AbpB) differentially affect colonization of rats' teeth by Streptococcus gordonii.

Streptococcus gordonii produces two alpha-amylase-binding proteins, AbpA and AbpB, that have been extensively studied in vitro. Little is known, however, about their significance in oral colonization and cariogenicity (virulence). To clarify these issues, weanling specific pathogen-free Osborne-Mendel rats, TAN : SPFOM(OM)BR, were inoculated either with wild-type strains FAS4-S or Challis-S or with strains having isogenic mutations of abpA, abpB, or both, to compare their colonization abilities and persistence on the teeth. Experiments were done with rats fed a sucrose-rich diet containing low amounts of starch or containing only starch. The mutants and wild-types were quantified in vivo and carious lesions were scored. In 11 experiments, S. gordonii was a prolific colonizer of the teeth when rats were fed the sucrose (with low starch)-supplemented diet, often dominating the flora. Sucrose-fed rats had several-fold higher recoveries of inoculants than those eating the sucrose-free, starch-supplemented diet, regardless of inoculant type. The strain defective in AbpB could not colonize teeth of starch-only-eating rats, but could colonize rats if sucrose was added to the diet. Strains defective in AbpA surprisingly colonized better than their wild-types. A double mutant deficient in both AbpA and AbpB (abpA/abpB) colonized like its wild-type. Wild-types FAS4-S and Challis-S had no more than marginal cariogenicity. Notably, in the absence of AbpA, cariogenicity was slightly augmented. Both the rescue of colonization by the AbpB- mutant and the augmentation of colonization by AbpA- mutant in the presence of dietary sucrose suggested additional amylase-binding protein interactions relevant to colonization. Glucosyltransferase activity was greater in mutants defective in abpA and modestly increased in the abpB mutant. It was concluded that AbpB is required for colonization of teeth of starch-eating rats and its deletion is partially masked if rats eat a sucrose-starch diet. AbpA appears to inhibit colonization of the plaque biofilm in vivo. This unexpected effect in vivo may be associated with interaction of AbpA with glucosyltransferase or with other colonization factors of these cells. These data illustrate that the complex nature of the oral environment may not be adequately modelled by in vitro systems.

Oral colonization and cariogenicity of Streptococcus gordonii in specific pathogen-free TAN:SPFOM(OM)BR rats consuming starch or sucrose diets.

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.

Influence of flight on protein catabolism, especially myofilament breakdown, in homing pigeons.

In order to study protein degradation during flight in homing, a high-performance liquid chromatography technique was developed for the quantitative analysis of N tau-methylhistidine. Secondly, it was necessary to confirm that the excretion of N tau-methylhistidine correlates with myofilament breakdown in homing pigeons. In these experiments, ten birds were subcutaneously injected with N tau-[14C]methylhistidine and the excreta were quantitatively collected for 1 week. Of the 94.5% radioactivity recovered, 87.1% was associated with N tau-[14C]methylhistidine and 6.1% with N-acetyl-N tau-[14C]methylhistidine. This rapid excretion of unmetabolized N tau-[14C]methylhistidine validates the assumption that the amount of N tau-methylhistidine excreted is a measure of myofilament catabolism in homing pigeons. The influence of endurance flight on protein breakdown was determined after flights from release sites 368-646 km away. Immediately after return, plasma urea and uric acid levels were increased, whereas plasma concentration of N tau-methylhistidine remained unchanged compared to unflown control birds. Flown pigeons excreted significantly more urea and N tau-methylhistidine within 24 h and significantly more urea and uric acid within 96 h after flight than unflown controls. Our findings support the hypothesis that in homing pigeons protein catabolism is increased during endurance flight. Elevated N tau-methylhistidine excretion probably results from repair processes in damaged muscle fibers, including breakdown of myofilaments.

Prevalence of the amylase-binding protein A gene (abpA) in oral streptococci.

Salivary amylase binds specifically to a number of oral streptococcal species. This interaction may play an important role in dental plaque formation. Recently, a 585-bp gene was cloned and sequenced from Streptococcus gordonii Challis encoding a 20.5-kDa amylase-binding protein (AbpA). The goal of this study was to determine if related genes are present in other species of oral streptococci. Biotinylated abpA was used in Southern blot analysis to screen genomic DNA from several strains representing eight species of oral streptococci. This probe hybridized with a 4.0-kb HindIII restriction fragment from all 13 strains of S. gordonii tested. The probe did not appear to bind to any restriction fragments from other species of amylase-binding oral streptococci including Streptococcus mitis (with the exception of 1 of 14 strains), Streptococcus crista (3 strains), Streptococcus anginosus (1 strain), and Streptococcus parasanguinis (1 strain), or to non-amylase-binding oral streptococci including Streptococcus sanguinis (3 strains), Streptococcus oralis (4 strains), and Streptococcus mutans (1 strain). Primers homologous to sequences within the 3' and 5' ends of abpA yielded products of 400 bp following PCR of genomic DNA from the Southern blot-positive strains. Several of these PCR products were cloned and sequenced. The levels of similarity of these cloned products to the abpA of S. gordonii Challis ranged from 91 to 96%. These studies reveal that the abpA gene appears to be specific to S. gordonii and differs from genes encoding amylase-binding proteins from other species of amylase-binding streptococci.

Identification and molecular analysis of rough-colony-specific outer membrane proteins of Actinobacillus actinomycetemcomitans.

Actinobacillus actinomycetemcomitans, a gram-negative bacterium isolated from the human mouth, has been implicated in the pathogenesis of early-onset periodontitis. Primary isolates cultured from subgingival plaque exhibit an adherent, rough colony phenotype which spontaneously converts to a nonadherent, smooth phenotype upon in vitro subculture. The rough colony variant produces abundant fimbriae and autoaggregates, while the smooth colony variant is planktonic and produces scant fimbriae. To begin to understand the significance of colony variation in biofilm formation by A. actinomycetemcomitans, outer membrane protein profiles of four isogenic rough and smooth colony variants were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Two proteins with relative molecular masses of 43 and 20 kDa were expressed by the rough colony variants exclusively. Expression of these proteins was not found to be dependent on growth phase, oxygen tension, or type of complex medium. N-terminal amino acid sequences of these proteins obtained by Edman degradation were compared with sequences from the University of Oklahoma A. actinomycetemcomitans genome database. Two contiguous open reading frames (ORFs) encoding proteins having sequence homology with these proteins were identified. The 43-kDa protein (RcpA [rough colony protein A]) was similar to precursor protein D of the general secretion pathway of gram-negative bacilli, while the 20-kDa protein (RcpB [rough colony protein B]) appeared to be unique. The genes encoding these proteins have been cloned from A. actinomycetemcomitans 283 and sequenced. A BLASTX (gapped BLAST) search of the surrounding ORFs revealed homology with other fimbria-related proteins. These data suggest that the genes encoding the 43-kDa (rcpA) and 20-kDa (rcpB) proteins may be functionally related to each other and to genes that may encode fimbria-associated proteins.