Advanced wastewater treatment with ozonation and granular activated carbon filtration: Inactivation of antibiotic resistance targets in a long-term pilot study.

The inactivation of antibiotic resistant bacteria (ARB) and genes (ARGs) in an advanced plant combining ozonation and granular activated carbon (GAC) filtration applied for effluent after conventional activated sludge treatment at a full-scale urban wastewater treatment plant was investigated for over 13 consecutive months. The nitrite compensated specific ozone dose ranged between 0.4 and 0.7 g O3/g DOC with short-time sampling campaigns (0.2-0.9 g O3/g DOC). Samples were analysed with culture-dependent methods for bacterial targets and with qPCR for genes. The log removal values were correlated with a decrease of the matrix UV absorption at 254 nm (ΔUV254) and indicated a range of ΔUV254 that corresponds to a sufficient membrane damage to affect DNA. For trimethoprim/sulfamethoxazole resistant E. coli, sul1, ermB and tetW, this phase was observed at ΔUV254 of ~30 % (~0.5 g O3/g DOC). For ampicillin resistant E. coli and blaTEM-1, it was observed around 35-40 % (~0.7 g O3/g DOC), which can be linked to mechanisms related to oxidative damages in bacteria resistant to bactericidal antibiotics. GAC treatment resulted in a further abatement for trimethoprim/sulfamethoxazole E. coli, sul1 and tetW, and in increase in absolute and relative abundance of ermB and blaTEM-1.

Synthesis, Antileishmanial Activity and in silico Studies of Aminoguanidine Hydrazones (AGH) and Thiosemicarbazones (TSC) Against Leishmania chagasi Amastigotes.

BACKGROUND: Leishmaniasis is a worldwide health problem, highly endemic in developing countries. Among the four main clinical forms of the disease, visceral leishmaniasis is the most severe, fatal in 95% of cases. The undesired side-effects from first-line chemotherapy and the reported drug resistance search for effective drugs that can replace or supplement those currently used in an urgent need. Aminoguanidine hydrazones (AGH's) have been explored for exhibiting a diverse spectrum of biological activities, in particular the antileishmanial activity of MGBG. The bioisosteres thiosemicarbazones (TSC's) offer a similar biological activity diversity, including antiprotozoal effects against Leishmania species and Trypanosoma cruzi. OBJECTIVES: Considering the impact of leishmaniasis worldwide, this work aimed to design, synthesize, and perform a screening upon L. chagasi amastigotes and for the cytotoxicity of the small "inhouse" library of both AGH and TSC derivatives and their structurally-related compounds. METHODS: A set of AGH's (3-7), TSC's (9, 10), and semicarbazones (11) were initially synthesized. Subsequently, different semi-constrained analogs were designed and also prepared, including thiazolidines (12), dihydrothiazines (13), imidazolines (15), pyrimidines (16, 18) azines (19, 20), and benzotriazepinones (23-25). All intermediates and target compounds were obtained with satisfactory yields and exhibited spectral data consistent with their structures. All final compounds were evaluated against L. chagasi amastigotes and J774.A1 cell line. Molecular docking was performed towards trypanothione reductase using GOLD® software. RESULTS: The AGH's 3i, 4a, and 5d, and the TSC's 9i, 9k, and 9o were selected as valuable hits. These compounds presented antileishmanial activity compared with pentamidine, showing IC50 values ranged from 0.6 to 7.27 µM, maximal effects up to 55.3%, and satisfactory SI values (ranged from 11 to 87). On the other hand, most of the resulting semi-constrained analogs were found cytotoxic or presented reduced antileishmanial activity. In general, TSC class is more promising than its isosteric AGH analogs, and the beneficial aromatic substituent effects are not similar in both series. In silico studies have suggested that these hits are capable of inhibiting the trypanothione reductase from the amastigote forms. CONCLUSION: The promising antileishmanial activity of three AGH's and three TSC's was characterized. These compounds presented antileishmanial activity compared with PTD, showing IC50 values ranged from 0.6 to 7.27 µM, and satisfactory SI values. Further pharmacological assays involving other Leishmania strains are in progress, which will help choose the best hits for in vivo experiments.

Effect of sweet potato vines on performance parameters and some carcass characteristics of rabbits.

Conventional feedstuffs in Brazil are expensive, which has led to the search for less conventional cheaper and locally available feedstuffs. Thus, this study was carried out to determine the dietary effect of dry sweet potato vines (SPV) on the performance and some carcass characteristics of rabbits. A total of twenty-seven weaned White New Zealand rabbits (14 male and 13 female) 35 days old with an average initial weight of 755 g were allocated into three treatments. Nine rabbits were assigned to each treatment in a completely randomized design. Three diets were formulated to similar protein and energy levels: 0SPV - diet without inclusion of dry sweet potato vines; 10SPV - diet with 10% alfalfa hay replaced by dry sweet potato vines; and 15SPV - diet with 15% of alfalfa hay replaced by dry sweet potato vines. The experiment lasted for 49 days during which data for feed intake and body weight were recorded. The daily feed intake ranged from 73.17 to 78.02 g; daily weight gain from 22.32 to 23.17 g; feed conversion ratio (FCR) from 3.16 to 3.49 and final live weight ranged from 1839.44 to 1880.55 g. None of the evaluated performance parameters as well as carcass weight, heart weight and percentages of fat and protein in meat were significantly affected by any of the tested dietary treatments. However, the liver weight was statistically lower in animals fed the diets containing 10% of SPV, mainly due to lower glucose content. Glycogen within the tissue, did not differ significantly among treatments. It was therefore concluded that up to 15% of SPV can successfully be included in the diet of rabbits as a cheaper replacement for alfalfa hay without adversely affecting performance.

Effect of dietary fiber concentrates on growth performance, gut morphology and hepatic metabolic intermediates in jundiá (Rhamdia quelen) / Efeito de concentrados de fibra alimentar sobre o desempenho de crescimento, morfologia intestinal e intermediários metabólicos hepáticos de jundiás (Rhamdia quelen)

A study was conducted to investigate the effect of Dietary Fiber Concentrates (DFCs) on growth performance, gut morphology, and hepatic metabolic intermediates in jundiá (Rhamdia quelen). At the end of the trial, growth and intestinal villus height was significantly (P< 0.05) higher in fish fed diets supplemented with DFCs. However, the animals in commercial prebiotic group showed higher values for this variable compared to the other treatments. Regarding the thickness of the epithelium bowel, it was greater in the Control group compared to animals supplemented with ß-glucan+mannan. Likewise, treatment with commercial prebiotic showed higher values of epithelium bowel compared to the DFCs. The fish supplemented with DFCs, had higher glycogen storage compared to the control group. These results indicate that DFCs can be considered as a beneficial dietary supplement for improving growth performance, gut morphology, and hepatic metabolic intermediates of jundiá.(AU)

O presente estudo foi conduzido para investigar o efeito de concentrados de fibras alimentares (CFAs) sobre o desempenho de crescimento, a morfologia intestinal e os parâmetros intermediários metabólicos hepáticos de jundiás (Rhamdia quelen). No final do experimento, o crescimento e a altura das vilosidades intestinais foram significativamente (P<0,05) maiores em peixes alimentados com dietas suplementadas com CFAs. No entanto, os animais suplementados com prebiótico comercial apresentaram valores mais elevados para essa variável em comparação com os outros tratamentos. Em relação à espessura do epitélio intestinal, esta foi maior nos animais do grupo controle em comparação com os animais suplementados com ß-glucano + manano. Da mesma forma, os peixes suplementados com prebiótico comercial apresentaram valores mais elevados do epitélio intestinal em comparação com os peixes suplementados com CFAs. Os peixes suplementados com CFAs obtiveram maior armazenamento de glicogênio em relação ao grupo controle. Esses resultados indicam que os CFAs podem ser utilizados como um suplemento alimentar benéfico para melhorar o desempenho do crescimento, a morfologia intestinal e os intermediários metabólicos hepáticos do jundiá.(AU)

Epidemiology of gingivitis in schoolchildren in Bucharest, Romania: a cross-sectional study.

BACKGROUND AND OBJECTIVE: Gingivitis is the most prevalent oral disease in children, being strongly associated to social gradients. Many studies have reported different results concerning the extent and intra-oral distribution of gingivitis in children. The aim of this study was to investigate the epidemiologic parameters and socio-related risk factors of gingivitis in the 10-17-year-old Bucharest schoolchildren population and to analyze its intra-oral distribution. MATERIAL AND METHODS: Cross-sectional data were obtained from 1595 schoolchildren, social condition being assigned using a simple questionnaire. Classes of students were used as clusters in a single-stage cluster sampling method. An intra-oral exam was performed for all the children included in this study. Silness and Löe scores, prevalence and the extent of gingivitis were calculated. RESULTS: The gingival scores showed a mild inflammation and the prevalence of gingivitis was 91%. Boys had a higher gingival (0.19 vs. 0.18; p < 0.05) and plaque scores (0.71 vs. 0.59; p < 0.01) than girls. Children who did not live in overcrowded households, whose parents had a better education and those who had direct access to school dental services displayed better gingival conditions (p < 0.05). Gingivitis was more severe on the upper teeth, with the maximum score being reached at the right upper lateral incisor (0.63 on distal surface). CONCLUSIONS: Gingival condition in Bucharest schoolchildren population was associated to social gradients. School dental services are also another factor that seems to be related with gingivitis.

Inhibitory effects of Zanthoxylum rhoifolium Lam. (Rutaceae) against the infection and infectivity of macrophages by Leishmania amazonensis.

Zanthoxylum rhoifolium Lam. (Rutaceae) has been traditionally used in the treatment of microbial infections and parasitic diseases. In the present study, the antileishmanial effect induced by the ethanol extract of stem barks from Z. rhoifolium (ZR-EEtOH) and its n-hexane fraction (ZR-FHEX) on infection and infectivity of murine macrophages by promastigote forms of Leishmania amazonensis were investigated. In different set of experiments, macrophages or promastigotes were pretreated with ZR-EEtOH or ZR-FHEX at non-lethal concentrations for 24 hours, and then macrophages were submitted to infection by promastigotes. Moreover, their effects on activation of macrophages, as well as on the DNA content, size and number of promastigotes by flow cytometry were also evaluated. The infection rate and the number of internalized amastigote forms were markedly decreased after pretreatment of macrophages or promastigotes when compared with non-treated cells. The increase in phagocytic capability and nitrite content was also observed. Furthermore, the decrease of DNA content, size and number of promastigotes was also observed. In conclusion, ZR-EEtOH and ZR-FHEX promoted a markedly significant antileishmanial effect and reduction of infection of macrophages, probably underlying defense mechanisms activation in macrophages. These findings reinforce the potential application of Z. rhoifolium in the treatment of leishmaniasis.

Living scaffolds: surgical repair using scaffolds seeded with human adipose-derived stem cells.

BACKGROUND: Decellularized porcine small intestinal submucosa (SIS) is a biological scaffold used surgically for tissue repair. Here, we demonstrate a model of SIS as a scaffold for human adipose-derived stem cells (ASCs) in vitro and apply it in vivo in a rat ventral hernia repair model. STUDY DESIGN: ASCs adherence was examined by confocal microscopy and proliferation rate was measured by growth curves. Multipotency of ASCs seeded onto SIS was tested using adipogenic, chondrogenic, and osteogenic induction media. For in vivo testing, midline abdominal musculofascial and peritoneal defects were created in Sprague-Dawley rats. Samples were evaluated for tensile strength, histopathology and immunohistochemistry. RESULTS: All test groups showed cell adherence and proliferation on SIS. Fibronectin-treated scaffolds retained more cells than those treated with vehicle alone (p < 0.05). Fresh stromal vascular fraction (SVF) pellets containing ASCs were injected onto the SIS scaffold and showed similar results to cultured ASCs. Maintenance of multipotency on SIS was confirmed by lineage-specific markers and dyes. Histopathology revealed neovascularization and cell influx to ASC-seeded SIS samples following animal implantation. ASC-seeded SIS appeared to offer a stronger repair than plain SIS, but these results were not statistically significant. Immunohistochemistry showed continued presence of cells of human origin in ASC-seeded repairs at 1 month postoperation. CONCLUSION: Pretreatment of the scaffold with fibronectin offers a method to increase cell adhesion and delivery. ASCs maintain their immunophenotype and ability to differentiate while on SIS. Seeding freshly isolated SVF onto the scaffold demonstrated that minimally manipulated cells may be useful for perioperative surgical applications within the OR suite. We have shown that this model for a "living mesh" can be successfully used in abdominal wall reconstruction.

Molluscicidal and leishmanicidal activity of the leaf essential oil of Syzygium cumini (L.) SKEELS from Brazil.

The chemical composition and biological potential of the essential oil extracted from Syzygium cumini leaves collected in Brazil were examined. GC/MS Analyses revealed a high abundance of monoterpenes (87.12%) in the oil. Eleven compounds were identified, with the major components being α-pinene (31.85%), (Z)-ß-ocimene (28.98%), and (E)-ß-ocimene (11.71%). To evaluate the molluscicidal effect of the oil, it was tested against Biomphalaria glabrata and the LC50 obtained was 90 mg/l. The essential oil also showed significant activity against Leishmania amazonensis, with an IC50 value equal to 60 mg/l. In addition, to evaluate its toxicity towards a non-target organism, the essential oil was tested against Artemia salina and showed a LC50 of 175 mg/l. Thus, the essential oil of S. cumini showed promising activity as a molluscicidal and leishmanicidal agent and might be valuable in combating neglected tropical diseases such as schistosomiasis and leishmaniasis. Further research is being conducted with regard to the purification and isolation of the most active essential-oil compounds.

[Outpatient anesthesia for patients with obstructive sleep apnea: results of a national survey]. / Ambulante Anästhesie bei Patienten mit obstruktivem Schlafapnoesyndrom: Ergebnisse einer deutschlandweiten Umfrage.

BACKGROUND: In Germany there is currently no national standard for the management of patients with obstructive sleep apnea syndrome (OSAS). The object of this survey was to obtain information on the treatment concept for patients with OSAS and to report on the current practice in Germany. METHODS: Data collection was obtained through an online questionnaire. A total of 12,113 members of the supporting anesthesia societies from all over Germany were invited to participate via e-mail. Additionally an announcement was made in a professional journal. RESULTS: A total of 1,671 questionnaires were analyzed. The average age of the respondents was 45 years, 64% were male and 36% were female. The average work experience was 16 years and 85% of the respondents were consultants. In total 85% of anesthesiologists were predominantly working in inpatient care and 12% were predominantly active in outpatient care. Of the respondents 63% preferred regional anesthesia, 20% preferred general anesthesia for patients with OSAS and 17% did not have a preference for a specific anesthesia procedure. Outpatient surgery for patients with OSAS was performed by 72% of the respondents using regional anesthesia and by 55% of the respondents using local anesthesia with sedation. Of the anesthesiologists 49% consented to outpatient surgery using general anesthesia and 14% to interventions involving the airways. Compared to anesthesiologists working predominantly in inpatient departments, those working predominantly in outpatient departments treated patients with OSAS more frequently on an outpatient basis, used general anesthesia significantly more often, discharged those patients significantly earlier and observed less complications. CONCLUSIONS: This survey shows that outpatient surgery for patients with sleep apnea is common practice in Germany. It is also performed when patients have moderate or severe OSAS and for respiratory tract surgery. This means that the management is not conform to the guidelines of the American Society of Anesthesiologists (ASA).

Application of pressure mapping techniques to measure push and gripping forces with precision.

Gripping and push forces, also named coupling forces, have induced effects on the transmission of the vibration in the upper limb. The assessment of the vibration exposure with powered tools thus requires that these man/machine coupling parameters are controlled and monitored. To date, no reliable metrological systems enable their precise measurements. This study first investigated how much precision could be expected from the pressure mapping technique for the determination of coupling forces by means of numerical integration. Then a specific procedure was worked out and validated to instrument hand-held tools and measure the coupling forces with regard to the appropriate current standards. The proposed method was applied as a case study on an ordinary breaker and an anti-vibration breaker.

[Smoking--a proven risk factor for periodontal disease?].

While bacterial dental plaque is widely considered as the etiological risk factor for the development of periodontal diseases, numerous publications from recent years pointed out the role of environmental factors like smoking as aggravating the severity of disease expression. The present paper reviews the updated literature linking epidemiologically between the presence of smoking habit and disease prevalence in the same population, as well as studies reporting on cell toxicity of nicotine and its by-products on gingival cells, negative effect on humoral and cell-mediated immune system, enhancement of bacterial plaque pathogeneity, and disruption of the wound healing processes. Finally, a negative effect is apparent on the supportive stage of the periodontal treatment, indicating lasting effect of smoking for years to come following the termination of active periodontal treatment.

[Periodontal disease--an additional risk factor for cardiovascular diseases?].

In 1989, a case-control study was published, linking between coronary heart disease and periodontal disease in the studied population. Since then, a number of additional studies, focused the attention to the possible role of dental infections in the pathogenesis of atherosclerosis. Some of these newer cohort studies, are prospective in nature, measuring incidence of the two diseases in large patient populations. The present article reviews these studies, and the proposed mechanisms which might explain the relationships between these two systemically distinct diseases.

The relationship between periodontal diseases and diabetes: an overview.

Diabetes mellitus, caused by the malfunction of insulin-dependent glucose and lipid metabolism, presents with the classical triad of symptoms: polydypsia, polyuria, and polyphagia which are often accompanied by chronic fatigue and loss of weight. Complications of diabetes mellitus include retinopathy, nephropathy, neuropathy, and cardiovascular disease. Periodontal diseases are infections affecting the periodontium and resulting in the loss of tooth support. The association between diabetes mellitus and periodontitis has long been discussed with conflicting conclusions. Both of these diseases have a relatively high incidence in the general population (diabetes 1% to 6% and periodontitis 14%) as well as a number of common pathways in their pathogenesis (both diseases are polygenic disorders with some degree of immunoregulatory dysfunction). On the one hand, numerous reports indicate a higher incidence of periodontitis in diabetics compared to healthy controls, while other reports fail to show such a relationship. Clarification of this dilemma is occurring as the diagnostic criteria for periodontitis and diabetes mellitus improve, controlled studies with increased sample sizes are carried out, and the studies take into account major confounding variables that impact on the pathogenesis of both diseases. Current studies tend to support a higher incidence and severity of periodontitis in patients with diabetes mellitus. The overview looks at the bidirectional relationship between periodontitis and diabetes. An analysis of the National Health and Nutrition Examination Survey (NHANES) III data set confirms the previously reported significantly higher prevalence of periodontitis in diabetics than in non-diabetics (17.3% versus 9%). The analysis of the data also shows that the prevalence of diabetes in patients with periodontitis is double that seen in the non-periodontitis patients (12.5% versus 6.3%) and that this difference is also statistically significant. The pathogenesis of the 2 diseases is reviewed with an emphasis on common genetic and immune mechanisms. On the basis of the overview, 2 hypotheses for testing the relationship between periodontitis and diabetes are discussed. The first proposes a direct causal or modifying relationship in which the hyperglycemia and hyperlipidemia of diabetes result in metabolic alterations that may then exacerbate bacteria-induced inflammatory periodontitis. The second hypothesis proposes that a fortuitous combination of genes (gene sets) could result in a host who, under the influence of a variety of environmental stressors, could develop either periodontitis or diabetes or both.

Confirmation of a unique intra-dimer cooperativity in the human hemoglobin alpha(1)beta(1)half-oxygenated intermediate supports the symmetry rule model of allosteric regulation.

The contribution of the alpha(1)beta(1)half-oxygenated tetramer [alphabeta:alphaO(2)betaO(2)] (species 21) to human hemoglobin cooperativity was evaluated using cryogenic isoelectric focusing. The cooperative free energy of binding, reflecting O(2)-driven protein structure changes, was measured as (21)DeltaG(c) = 5.1 +/- 0. 3 kcal for the Zn/FeO(2) analog. For the Fe/FeCN analog, (21)DeltaG(c) was estimated as 4.0 kcal after correction for a CN ligand rearrangement artifact, demonstrating that ligand rearrangement does not invalidate previous conclusions regarding this species. In the context of the entire Hb cooperativity cascade, which includes eight intermediate species, the 21 tetramer is highly abundant relative to the other doubly-ligated species, providing strong support for the previously determined consensus partition function of O(2) binding and for the Symmetry Rule model of hemoglobin cooperativity (Ackers et al., Science 1992;255:54-63). Cooperativity of normal human hemoglobin is shown to depend on site-configuration, and not solely the number of O(2) bound, nor the occupancy of alpha vs. beta subunits. Verification of a unique contribution from the alpha(1)beta(1)doubly-oxygenated species to the equilibrium O(2) binding curve strongly reinforces the Symmetry Rule interpretation that the alpha(1)beta(1)dimer acts both as a structural and functional element in cooperative O(2) binding.

Identifying and modelling prognostic factors with censored data.

A major issue in the analysis of diseases is the identification and assessment of prognostic factors relevant to the development of the illness. Statistical analyses within the proportional hazards framework suffer from a lack of flexibility due to stringent model assumptions such as additivity and time-constancy of effects. In this paper we use tree-based models and varying coefficient models to allow for detectability of prognostic factors with possibly non-additive, non-linear and time-varying impact on disease development. Questions concerning model and smoothing parameter selection are addressed. An analysis of a data set of breast cancer patients demonstrates the ability of these methods to reveal additional insight into the disease influencing mechanisms.

Modelling and exploring human sleep with event history analysis.

In this paper we propose the use of statistical models of event history analysis for investigating human sleep. These models provide appropriate tools for statistical evaluation when sleep data are recorded continuously over time or on a fine time grid, and are classified into sleep stages such as REM and nonREM as defined by Rechtschaffen and Kales (1968). In contrast to conventional statistical procedures, event history analysis makes full use of the information contained in sleep data, and can therefore provide new insights into non-stationary properties of sleep. Probabilities of or intensities for transitions between sleep stages are the basic quantities for characterising sleep processes. The statistical methods of event history analysis aim at modelling and estimating these intensities as functions of time, taking into account individual sleep history and assessing the influence of factors of interest, such as hormonal secretion. In this study we suggest the use of non-parametric approaches to reveal unknown functional forms of transition intensities and to explore time-varying and non-stationary effects. We then apply these techniques in a study of 30 healthy male volunteers to assess the mean population intensity and the effects of plasma cortisol concentration on the transition between selected sleep stages as well as the influence of elapsed time in a current REM period on the intensity for a transition to nonREM. The most interesting findings are that (a) the intensity of the nonREM-to-REM transitions after sleep onset in young men shows a periodicity which is similar to that of nonREM/REM cycles; (b) 30-45 min after sleep onset, young men reveal a great propensity to pass from light sleep (stages 1 or 2) into slow-wave sleep (SWS) (stages 3 or 4); (c) high cortisol levels imposed additional impulses on the transition intensity of (i) wake to sleep around 2 h after sleep onset, (ii) nonREM to REM around 6 h later, (iii) stage 1 or stage 2 sleep to SWS around 2, 4 and 6 h later and (iv) SWS to stage 1 or stage 2 sleep about 2 h later. Moreover, high cortisol concentrations at the beginning of REM periods favoured the change to nonREM sleep, whereas later their influence on a nonREM change became weak and weaker. As sleep data are also available as event-oriented data in many studies in sleep research, event history analysis applied additionally to conventional statistical procedures, such as regression analysis or analysis of variance, could help to acquire more information and knowledge about the mechanisms behind the sleep process.

Adherence of periodontopathic bacteria to bioabsorbable and non-absorbable barrier membranes in vitro.

Guided tissue regeneration (GTR) techniques are increasingly used for the treatment of periodontal defects, or in conjunction with dental implant procedures. As adhesion of bacteria to barrier membranes used in these techniques may lead to failure, a prerequisite for treatment success is an infection-free healing process. The present study examined the adhesion of 3 periodontal pathogenic bacteria: Actinobacillus actinomycetemcomitans, Treponema denticola and Porphyromonas gingivalis, to 3 barrier membranes: Collagen, (Biomend) PTFE, (TefGen-FD) and e-PTFE, (Gore-Tex). The membranes were incubated with 3[H]-thymidine labeled bacteria, and the number of adherent bacteria was calculated using a scintillation counter. The effect of albumin coating on bacterial adherence to the membranes was also studied. Bacterial adherence to the membranes was further examined by scanning electron microscopy (SEM). The results show that the adherence of all bacterial strains to collagen membranes was significantly higher than to the other membranes tested. Precoating of the membranes with albumin did not change the bacterial adherence significantly. These findings are of importance in evaluating the ability of periodontal bacteria to colonize and infect different types of barrier membranes.

Adhesion of periodontal bacteria to titanium, and titanium alloy powders.

In this study, the adhesion of radioactively labeled Actinomyces viscosus (A. viscosus), Actinobacillus actinomicetemcomitans (Aa) and Porphyromonas gingivalis (P. gingivalis) to titanium (Ti) and Ti-6-Al-4V alloy (Ti-alloy) coated with albumin or human saliva was investigated. All the tested bacteria displayed greater attachment to Ti-alloy than to Ti. P. gingivalis exhibited less adhesion to Ti and Ti-alloy than did the other bacterial strains. Adhesion of A. viscosus and Aa was greatly reduced when Ti or Ti-alloy were coated with albumin or saliva. P. gingivalis demonstrated a lesser reduction in adhesion to albumin or saliva-coated surfaces. The results show that oral bacteria have different adhesion affinities for Ti and Ti-alloy and that both albumin and human saliva reduce bacterial adhesion.

The fnr gene of Bacillus licheniformis and the cysteine ligands of the C-terminal FeS cluster.

In the facultatively anaerobic bacterium Bacillus licheniformis a gene encoding a protein of the fumarate nitrate reductase family of transcriptional regulators (Fnr) was isolated. Unlike Fnr proteins from gram-negative bacteria, but like Fnr from Bacillus subtilis, the protein contained a C-terminal cluster of cysteine residues. Unlike in Fnr from B. subtilis, this cluster (Cys226-X2-Cys229-X4-Cys234) is composed of only three Cys residues, which are supposed to serve together with an internal residue (Cys71) as the ligands for an FeS center. Transfer of the B. licheniformis gene to an fnr mutant of B. subtilis complemented the ability for synthesis of nitrate reductase during anaerobic growth.