The Diversity of Nitrogen-Cycling Microbial Genes in a Waste Stabilization Pond Reveals Changes over Space and Time that Is Uncoupled to Changing Nitrogen Chemistry.

Nitrogen removal is an important process for wastewater ponds prior to effluent release. Bacteria and archaea can drive nitrogen removal if they possess the genes required to metabolize nitrogen. In the tropical savanna of northern Australia, we identified the previously unresolved microbial communities responsible for nitrogen cycling in a multi-pond wastewater stabilization system by measuring genomic DNA and cDNA for the following: nifH (nitrogen fixation); nosZ (denitrification); hzsA (anammox); archaeal AamoA and bacterial BamoA (ammonia oxidation); nxrB (nitrite oxidation); and nrfA (dissimilatory NO3 reduction to NH3). By collecting 160 DNA and 40 cDNA wastewater samples and measuring nitrogen (N)-cycling genes using a functional gene array, we found that genes from all steps of the N cycle were present and, except for nxrB, were also expressed. As expected, N-cycling communities showed daily, seasonal, and yearly shifts. However, contrary to our prediction, probes from most functional groups, excluding nosZ and AamoA, were different between ponds. Further, different genes that perform the same N-cycling role sometimes had different trends over space and time, resulting in only weak correlations between the different functional communities. Although N-cycling communities were correlated with wastewater nitrogen levels and physico-chemistry, the relationship was not strong enough to reliably predict the presence or diversity of N-cycling microbes. The complex and dynamic response of these genes to other functional groups and the changing physico-chemical environment provides insight into why altering wastewater pond conditions can result an abundance of some gene variants while others are lost.

Multiple approaches to assess the safety of artisanal marine food in a tropical estuary.

In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference.

Role of neurostimulation in migraine.

Chronic forms of headache characterized by daily or almost daily headache, affect almost 3 % of general population. They represent the most disabling forms of headache inducing high degree of disability, poor quality of life for patients. During the last decades, several neuromodulatory surgical techniques have been developed for the management of headaches that are unresponsive to medical treatment. Invasive and non invasive central and/or peripheral neurostimulation techniques have been developed by different research groups with encouraging results for different type of headaches. In this report, the acute effect of non invasive vagus nerve stimulation (nVNS) (gammacore) was evaluated to treat migraine attacks in a population of patients affected by high-frequency episodic migraine or chronic migraine. The aim of this study was to verify the efficacy of nVNS to treat migraine attacks in this specific category of patients.

Effect of pH regulation by sulfate-reducing bacteria on corrosion behaviour of duplex stainless steel 2205 in acidic artificial seawater.

Sulfate-reducing bacteria (SRB) can regulate environmental pH because of their metabolism. Because local acidification results in pitting corrosion, the potential capacity of pH regulation by SRB would have important consequences for electrochemical aspects of the bio-corrosion process. This study focused on identifying the effect of pH on the corrosion of duplex stainless steel 2205 in a nutrient-rich artificial seawater medium containing SRB species, Desulfovibrio vulgaris. Duplex stainless steel samples were exposed to the medium for 13 days at 37°C at pH ranging from 4.0 to 7.4. The open-circuit potential value, sulfide level, pH and number of bacteria in the medium were recorded daily. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the properties of the biofilms at the end of the experiments and the corrosion behaviour of the material. Inductively coupled plasma mass spectrometry was used to measure the concentration of cations Fe, Ni, Mo, Mn, Cr in the experimental solution after 13 days. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDX) were used for surface analysis. The results showed the pH changed from acidic values set at the beginning of the experiment to approximately pH 7.5 after 5 days owing to bacterial metabolism. After 13 days, the highest iron concentration was in the solution that was initially at pH 4 accompanied by pitting on the stainless steel. Sulfur was present on all specimens but with more sulfur at pH 4 in the EDX spectra. EIS showed the film resistance of the specimen at pH 4 was much lower than at pH 7.4 which suggests the corrosion resistance of the stainless steel was better at higher pH. The results of this study suggest that the corrosion process for the first few days exposure at low pH was driven by pH in solution rather than by bacteria. The increasing pH during the course of the experiment slowed down the corrosion process of materials originally at low pH. The nature and mechanism of SRB attack on duplex stainless steel at different acidic environments are discussed.

A study of bacteria adhesion and microbial corrosion on different stainless steels in environment containing Desulfovibrio vulgaris.

Stainless steel is an important material used in many applications due to its mechanical strength and corrosion-resistant properties. The high corrosion resistance of stainless steel is provided by the passive film. Different stainless steels have different alloy elements and surface properties which could have a significant influence on bacterial attachment to the surface and thus might result in different microbial corrosion behaviours. In this study, the effect of adhesion of sulfate-reducing bacteria (SRB) on corrosion behaviour in artificial seawater on different stainless steels was investigated. Stainless steel materials used were SS 410, SS 420, SS 316 and DSS 2205 and pure chromium. The contact angle was measured to study the effect of surface properties of materials. Adhesion was measured by counting cells attached to the surface of materials. The corrosion behaviour of the materials was measured by electrochemical testing including measuring open circuit potential, electrochemical impedance spectroscopy and potentiodynamic behaviour. The long-term corrosion behaviour of each material was studied after six months of exposure by measuring weight loss and surface analysis with scanning electron microscope with energy-dispersive X-ray analysis. Hydrophobicity had a strong effect on bacterial attachment. Alloying elements e.g. nickel also had shown its ability to attract bacteria to adhere on the surface. However, the corrosion rate of different materials is determined not only by bacterial attachment but also by the stability of the passive film which is determined by the alloying elements, such as Mo and Cr. Chromium showed high resistance to corrosion, possibly due to toxicity on bacterial attachment. The nature of bacterial attachment and corrosion behaviour of the materials are discussed.

Species distribution and antifungal susceptibility of 358 Trichosporon clinical isolates collected in 24 medical centres.

OBJECTIVES: To provide species distribution and antifungal susceptibility profiles of 358 Trichosporon clinical isolates collected from 24 tertiary-care hospitals. METHODS: Species identification was performed by sequencing the IGS1 region of rDNA. Antifungal susceptibility testing for amphotericin B, fluconazole, voriconazole and posaconazole followed the Clinical and Laboratory Standards Institute reference method. Tentative epidemiologic cutoff values (97.5% ECVs) of antifungals for Trichosporon asahii were also calculated. RESULTS: Isolates were cultured mostly from urine (155/358, 43.3%) and blood (82/358, 23%) samples. Trichosporon asahii was the most common species (273/358, 76.3%), followed by T. inkin (35/358, 9.7%). Isolation of non-T. asahii species increased substantially over the last 11 years [11/77 (14.2%) from 1997 to 2007 vs. 74/281, (26.3%) from 2008 to 2018, p0.03]. Antifungal susceptibility testing showed high amphotericin B minimum inhibitory concentrations against Trichosporon isolates, with higher values for T. faecale. The ECV for amphotericin B and T. asahii was set at 4 µg/mL. Among the triazole derivatives, fluconazole was the least active drug. The ECVs for fluconazole and posaconazole against T. asahii were set at 8 and 0.5 µg/mL, respectively. Voriconazole showed the strongest in vitro activity against the Trichosporon isolates; its ECV for T. asahii was set at 0.25 µg/mL after 48 hours' incubation. CONCLUSIONS: Trichosporon species diversity has increased over the years in human samples, and antifungal susceptibility profiles were species specific. Trichosporon asahii antifungal ECVs were proposed, which may be helpful to guide antifungal therapy.

The "You Are Not Alone" care program for liver transplantation.

Current clinical practice is based on the principles of efficacy, appropriateness, efficiency, quality, and safety. Compliance with these tenets requires experienced medical and nursing staff, and active participation of patients and their families in the planned therapeutic program. To match patients' expectations on quality and safety of care and spur active participation in the transplant care process, we set up an integrated, multiphase, multidisciplinary care program devoted to liver transplantation (LT) candidates, engrafted patients, and their families: the "Non Sei Solo" care program (You Are Not Alone). The basic principle of the care program was that, to provide efficient and effective education to their patients, health care professionals need to learn how to teach and what to teach, acquire successful communication skills, and monitor the process of education. The methodology encompassed 5 distinct phases: phase 1, exploration of patients' needs, by means of a questionnaire devoted to waitlisted and engrafted patients and their care givers; and phase 2, creation of 16 patient-oriented educational brochures directed to patients and their families. Once created, the educational brochures were presented, discussed, and amended during a consensus meeting involving all transplantation nurses and physicians (phase 3). To acquire the necessary skills and ease communication with patients, the transplantation nurses, physicians, surgeons, and anesthesiologists attended a 6-month counseling course under the tutorial of an expert counselor (phase 4). Finally, in June 2007 the program started officially with monthly meetings with patients and their families, guided hospital tours on patient request, and activation of a toll-free phone number to provide support to patients and answer their questions.

The Candida albicans AAA ATPase homologue of Saccharomyces cerevisiae Rix7p (YLL034c) is essential for proper morphology, biofilm formation and activity of secreted aspartyl proteinases.

Proper morphology is essential for the ability of Candida albicans to switch between yeast and hyphae and thereby sustain its virulence. Here we identified, by differential screening, a novel C. albicans AAA ATPase encoding gene, CaYLL34 (RIX7), with enhanced expression in hyphae. Phylogenetic analysis suggests that CaYLL34 belongs to a "VCP-like" subgroup of AAA ATPases essential for yeast viability and contains a bipartite nuclear localization signal. Inactivation of one copy of CaYLL34, by the URA-Blaster method, generated the heterozygous mutant strain M61. This strain has severe phenotypic alterations, such as a highly increased vacuole, abnormal cell shape and reduced growth in different conditions. Also, major pathogenicity factors are affected in M61, for instance, a significant decrease of hypha formation (>90%), surface biofilm adhesion (86%) and secreted aspartyl proteinase activity (76.5%). Our results show that the partial impairment of CaYll34p cellular levels is sufficient to affect the proper cellular morphology and pathogenicity factors and suggest that this protein is required for biogenesis of ribosomal subunits. Accordingly, we propose that the product of CaYLL34 could be tested as a novel target for antifungal drugs.

Prevalence rates and antifungal susceptibility profiles of the Candida parapsilosis species complex: results from a nationwide surveillance of candidaemia in Brazil.

The genetically heterogeneous taxon Candida parapsilosis was recently reclassified into three species: Candida parapsilosis, Candida orthopsilosis and Candida metapsilosis. The prevalences of these species among 141 bloodstream isolates tested in Brazil were 88% for C. parapsilosis, 9% for C. orthopsilosis, and 3% for C. metapsilosis. Except for three C. orthopsilosis isolates that were considered resistant to 5-flucytosine, all isolates representing the different species of this complex were susceptible to polyenes, triazoles and caspofungin.

Concentrations of heavy metals in oysters from the coastline of Northern Territory, Australia.

The concentrations of five metals in oysters from ten locations along the Northern Territory coastline were determined during the dry season of 1989. The measured concentrations of iron, cadmium, zinc, manganese and copper in oysers were 11.6-274, 0.17-9.1, 4.79-735, 0.25-69.85 and nd-70.2 µg g(-1) wet weight. The level of cadmium exceeded the National Health and Medical Research Council (NHMRC) recommended limit at five sites. The largest fluctuation occurred in zinc and cadmium while the other metals displayed much less variation.

An analysis of the control of phosphorylation-coupled respiration in isolated plant mitochondria.

The control of phosphorylation-coupled respiration in isolated turnip (Brassica rapa) mitochondria was investigated according to the principles of metabolic control analysis as developed by H. Kacser and J. A. Burns ([1973] Symp Soc Exp Biol 32: 65-104) and R. Heinrich and T. A. Rapoport ([1974] Eur J Biochem 42: 97-105). Inhibitor titration studies were used to determine quantitatively the amount of control exerted by four individual processes-cytochrome bc(1), cytochrome oxidase, H(+)-ATPase, and the adenine nucleotide carrier-on respiratory flux under ADP-excess (state 3) and ADP-limited (state 4) conditions with a range of respiratory substrates. Under state 3 conditions control strength was found to be distributed between cytochrome oxidase, cytochrome bc(1), and H(+)-ATPase in decreasing order of importance. The adenine nucleotide carrier exerted no control on respiratory flux under these conditions. Control strength at each step was found to vary with different substrates and with the respiratory flux as altered by ADP supply, i.e. virtually zero control strength at cytochrome oxidase and cytochrome bc(1) under state 4 conditions.

Enzymatic inactivation of bradykinin by rat brain neuronal perikarya.

1. Bradykinin (Bk; Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-Pro7-Phe8-Arg8) inactivation by bulk isolated neurons from rat brain is described. 2. Bk is rapidly inactivated by neuronal perikarya (4.2 +/- 0.6 fmol/min/cell body). 3. Sites of inactivating cleavages, determined by a kininase bioassay combined with a time-course Bk-product analysis, were the Phe5-Ser6, Pro7-Phe8, Gly4-Phe5, and Pro3-Gly4 peptide bonds. The cleavage of the Phe5-Ser6 bond inactivated Bk at least five fold faster than the other observed cleavages. 4. Inactivating peptidases were identified by the effect of inhibitors on Bk-product formation. The Phe5-Ser6 bond cleavage is attributed mainly to a calcium-activated thiol-endopeptidase, a predominantly soluble enzyme which did not behave as a metalloenzyme upon dialysis and was strongly inhibited by N-[1(R,S)-carboxy-2-phenylethyl]-Ala-Ala-Phe-p-aminobenzoate and endo-oligopeptidase A antiserum. Thus, neuronal perikarya thiol-endopeptidase seems to differ from endo-oligopeptidase A and endopeptidase 24.15. 5. Endopeptidase 24.11 cleaves Bk at the Gly4-Phe5 and, to a larger extent, at the Pro7-Phe8 bond. The latter bond is also cleaved by angiotensin-converting enzyme (ACE) and prolyl endopeptidase (PE). PE also hydrolyzes Bk at the Pro3-Gly4 bond. 6. Secondary processing of Bk inactivation products occurs by (1) a rapid cleavage of Ser6-Pro7-Phe8-Arg8 at the Pro7-Phe8 bond by endopeptidase 24.11, 3820ACE, and PE; (2) a bestatin-sensitive breakdown of Phe8-Arg9; and (3) conversion of Arg1-Pro7 to Arg1-Phe5, of Gly4-Arg9 to both Gly4-Pro7 and Ser6-Arg9, and of Phe5-Arg9 to Ser6-Arg9, Phe8-Arg9, and Ser6-Pro7, by unidentified peptidases. 7. A model for the enzymatic inactivation of bradykinin by rat brain neuronal perikarya is proposed.

The Candida albicans AAA ATPase homologue of Saccharomyces cerevisiae Rix7p (YLL034c) is essential for proper morphology, biofilm formation and activity of secreted aspartyl proteinases

Proper morphology is essential for the ability of Candida albicans to switch between yeast and hyphae and thereby sustain its virulence. Here we identified, by differential screening, a novel C. albicans AAA ATPase encoding gene, CaYLL34 (RIX7), with enhanced expression in hyphae. Phylogenetic analysis suggests that CaYLL34 belongs to a [quot ]VCP-like[quot ] subgroup of AAA ATPases essential for yeast viability and contains a bipartite nuclear localization signal. Inactivation of one copy of CaYLL34, by the URA-Blaster method, generated the heterozygous mutant strain M61. This strain has severe phenotypic alterations, such as a highly increased vacuole, abnormal cell shape and reduced growth in different conditions. Also, major pathogenicity factors are affected in M61, for instance, a significant decrease of hypha formation (>90%), surface biofilm adhesion (86%) and secreted aspartyl proteinase activity (76.5%). Our results show that the partial impairment of CaYll34p cellular levels is sufficient to affect the proper cellular morphology and pathogenicity factors and suggest that this protein is required for biogenesis of ribosomal subunits. Accordingly, we propose that the product of CaYLL34 could be tested as a novel target for antifungal drugs.