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The aim of the present study was to validate methods of stool sample conservation for the egg hatch test (EHT). This study involved the use of a bovine naturally infected predominantly by Cooperia spp. and one equine naturally infected predominantly by cyathostomins characterized as susceptible to benzimidazoles in the EHT. Fecal samples were submitted to three treatments: aerobic methods (anaerobic storage in plastic bottles, anaerobic storage in vacuum-sealed bags or aerobic storage in plastic bags), under two temperature conditions (room temperature and refrigeration) analyzed at four different assessment times (48, 72, 96 and 120 h). As the standard test, an assay was also performed within 3 h. The tests were performed in triplicate for each drug concentration and with three experimental repetitions at one-week intervals. Two criteria were used for the storage methods: hatchability in the negative control group and sensitivity of the eggs to thiabendazole, comparing the EC50 and 95% confidence interval for each treatment to those of the standard test and the other repetitions. Bovine samples can be stored for up to 96 h and refrigerated vacuum storage can be used, ensuring hatchability of the negative control and sensitivity of the eggs to thiabendazole. For equine samples, no forms of storage were indicated due to the variation among the repetitions and the reduction in the sensitivity of the eggs to thiabendazole, which could result in a false positive detection of resistance. [Display omitted] • Bovine feces can be stored for up to 96 h, but the EHT must be performed within 3 h for equine feces samples. • Samples stored at room temperature have good hatchability but with reduced sensitivity to thiabendazole in the EHT. • Vacuum-sealed refrigerated samples ensure adequate hatchability. [ABSTRACT FROM AUTHOR]

Psychrotrophic strains of the foodborne pathogen Bacillus cereus can multiply during the refrigerated storage of food products. The aim of this study was to determine the impact of anaerobiosis on the growth of two psychrotrophic B. cereus strains exposed to acidic pH at a cold temperature in a laboratory medium. At 10 °C, growth occurred at pH values equal to or higher than 5.7 during anaerobiosis, whereas aerobic growth was observed from pH 5.4. Growth rates during aerobiosis were similar at pH 5.4 and pH 7. No growth was observed for the two tested strains at 8 °C without oxygen regardless of the pH; however, both strains grew at this temperature from pH 5.4 in the presence of oxygen. These pH growth limits in aerobiosis are consistent with those reported for different strains and different foods or media, but no other studies have described anaerobic growth at acidic pH values. The maximal B. cereus concentration was approximately 6.0 log 10 CFU/ml for cultures in the absence of oxygen and approximately 8.0 log 10 CFU/ml for cultures in the presence of oxygen. In conclusion, we found that the combination of anaerobiosis, pH < 5.7 at 10 °C, or anaerobiosis and temperatures ≤8 °C prevent psychrotrophic B. cereus growth. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS) consists of three covalently linked domains: the lipid A, the core region and the O antigen (OAg), consisting of repeats of an oligosaccharide. Salmonella enterica serovar Enteritidis ( S . Enteritidis) produces a LPS with two OAg preferred chain lengths: a long (L)-OAg controlled by Wzz SE and a very long (VL)-OAg controlled by Wzz fepE . In this work, we show that OAg produced by S . Enteritidis grown in E minimal medium also presented two preferred chain-lengths. However, a simultaneous and opposing change in the production of L-OAg and VL-OAg was observed in response to oxygen availability. Biochemical and genetics analyses indicate that this process is regulated by transcriptional factors Fnr and ArcA by means of controlling the transcription of genes encoding Wzz SE and Wzz fepE in response to oxygen availability. Thus, our results revealed a sophisticated regulatory mechanism involved in the adaptation of S . Enteritidis to one of the main environmental cues faced by this pathogen during infection. [ABSTRACT FROM AUTHOR]

In this study, we aimed at optimizing the growth of Lactobacillus rhamnosus 64 in whey permeate supplemented with different ingredients and we also studied the effects of mild stresses on the response to heat and oxidative challenge. Supplementation of diluted whey permeate with yeast extract, tryptone, Tween 80 and Mn–Mg produced ca. 10 10 CFU/mL of L. rhamnosus 64 under pH controlled fermentation in anaerobiosis. Cells were exposed to different mild stresses (aerobic: 1 h air 0.3 vol vol −1 min, pH 6, 37 °C); heat (1 h, pH 6, 45 °C, anaerobiosis) and acid (1 h, pH 5, 37 °C, anaerobiosis), followed by heat (55 °C) or oxidative (0.4 mmol/L H 2 O 2 ) challenge (15 min). Oxidative challenge was more detrimental compared to heat challenge. Anaerobic incubation, cell harvesting at the stationary phase and mild heat stress were more effective for reducing cell death towards heat challenge, whereas cheese whey-starch was effective towards cell protection to spray drying and storage. No effects on cell survival to spray drying were observed when mild stresses were used to increase resistance to spray drying. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the effect of anaerobiosis on the formation of Bacillus cereus spores and their resulting properties. For this purpose, an appropriate sporulation medium was developed (MODs). Sporulation of 18 strains from different phylogenetic groups of B. cereus was studied in MODs medium in aerobiosis and anaerobiosis. In anaerobiosis, sporulation ability was weaker and more heterogeneous than in aerobiosis. Among tested strains, B. cereus AH187 produced the highest level of spores in anaerobiosis. This strain was therefore chosen to study spore properties. Spores produced in anaerobiosis were more resistant to wet heat at 90 °C, 92.5 °C, 95 °C, 97.5 °C and 100 °C. For example, D 90 were 21,09 ± 1.70 and 81.87 ± 2.00 for aerobiosis and anaerobiosis conditions, respectively. Spores produced in anaerobiosis have a z-value of 7.70 °C compared with 10.52 °C for spores produced in aerobiosis. Spores produced in anaerobiosis were also more resistant to 1 M NaOH, 1 M nitrous acid and pulsed light at fluences of 0.34 J cm−2 and 0.49 J cm−2. No difference in resistance to UV-C, 5% hydrogen peroxide or 0.25 mM formaldehyde was observed between these two conditions. In the presence of l-alanine, spores produced in anaerobiosis germinated more efficiently than spore produced in aerobiosis. No difference in germination was observed with inosine as inducer. No difference in the size of spores produced in the different conditions was observed by transmission electron microscopy. However, spores obtained under anaerobic conditions had a damaged exosporium, or in some cases a completely detached exosporium, unlike spores produced under aerobic conditions. This study shows that few spores are formed under anaerobic condition; nevertheless, this condition has an impact on the spore properties of B. cereus AH 187 strain. Spores obtained under anaerobic condition were more resistant to heat and to some chemical compounds. This is an important feature, considering the risk associated with the presence of this pathogen in thermally processed and packaged food in absence of oxygen. [ABSTRACT FROM AUTHOR]

Abstract: In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly improved B. cereus anaerobic growth at cold temperature. Addition of hydrogenated phosphatidylcholine containing saturated, high melting point, fatty acids did not modify growth. Fatty acids from phospholipids, from spinach and from hydrogenated phosphatidylcholine, although normally very rare in B. cereus, were inserted in the bacterium membrane. Addition of phospholipids rich in unsaturated fatty acids to cold and anaerobic cultures, increased fluidity of B. cereus membrane lipids, to the same level as those from B. cereus normally cold adapted, i.e. grown aerobically at 15 °C. B. cereus is therefore able to use external fatty acids from foods or from the growth medium to adapt its membrane to cold temperature under anaerobiosis, and to recover the maximal population density achieved at optimal temperature. [Copyright &y& Elsevier]

Highlights: [•] Escherichia coli contains two l-asparaginase isozymes with distinct localization, kinetics and regulation. [•] Mutant strains were used to examine the roles of these enzymes in l-asparagine utilization. [•] We report that l-asparaginase II permits growth on asparagine and glycerol under anaerobic conditions. [•] We propose that this enzyme is the first step in a co-regulated pathway leading to fumarate. [•] The pathway is regulated by anaerobiosis and cAMP and provides a terminal elector acceptor. [ABSTRACT FROM AUTHOR]

Abstract: The impact of fermentative metabolism at low temperature on cell division of Bacillus cereus was studied. Fermentation at 37 °C had no influence on the division of bacteria. Aerobic cultures at 15 °C produced larger cells than at 37 °C, but cell division was normal. In fermentative cultures at 15 °C, no increase in CFU ml−1 was observed. However, A 600 increased, due to formation of long filaments. Transmission electronic microscopy and light microscopy with fluorescent staining showed several nucleic acid entities separated by a hydrophobic membrane, indicating that each filament contained several individual cells attached by peptidoglycan. When left in air at room temperature, one filament gave several daughter cells, this means that one CFU formed by one filament may represent a greater contamination potential than one CFU formed by a single cell. Division was observed in cultures at 15 °C with anaerobic respiration in the presence of nitrates. Possible filamentous growth must thus be taken into account to avoid underestimating B. cereus growth in vacuum or modified atmosphere packaged foods stored at low temperature. [Copyright &y& Elsevier]

Abstract: Entamoeba histolytica is among the most deadly parasites accounting for the second highest mortality rate among parasitic diseases. Nevertheless, contrary to trypanosomatids, this protozoan in hardly studied by parasitology groups. This astonishing discrepancy is largely due to the remarkable intricate conditions required for parasite proliferation in vitro, particularly whenever large cell numbers are required. The present study was undertaken in order to optimize E. histolytica culturing harvest, using mineral oil layers preventing culture medium-air contact to maintain anaerobic conditions in culture plate wells. 2×104 trophozoites were plated on each well in 2.0mL YI-S-33 medium, supplemented with bovine serum and 700μL mineral oil. Parasites were daily quantified by light microscopy counting for up to 96h and trophozoite motility was also assessed. We notice that E. histolytica cultures in 24-well plates reached several-fold higher cell densities, particularly whenever the mineral oil layer was placed on top of the medium surface, blocking the air interface. At least 99% of the parasites were vigorously motile for 72h in oil-containing wells, whereas only less than 5% displayed significant motility in oil-devoid wells. In order to determine whether such different growth responses were due at least in part to the oxidative stress, we used the reactive oxidant species fluorescent probe dihydroethidium (DHE). The remarkably higher DHE parasite labeling in oil-devoid cultures indicate that oxidative stress reduction can play a significant role in elevated growth rates observed in oil supplemented cultures. Propidium iodide and Trypan blue dye-exclusion assays indicate that parasite necrosis resulted from the stressing conditions. The present study indicates that E. histolytica culturing in oil-sealed wells may comprise a valuable tool for bioactivity of antiparasitic compounds. [Copyright &y& Elsevier]

Abstract: Burkholderia pseudomallei infections are fastidious to treat with conventional antibiotic therapy, often involving a combination of drugs and long-term regimes. Bacterial genetic determinants contribute to the resistance of B. pseudomallei to many classes of antibiotics. In addition, anaerobiosis and hypoxia in abscesses typical of melioidosis select for persistent populations of B. pseudomallei refractory to a broad spectrum of antibacterials. We tested the susceptibility of B. pseudomallei to the drugs hydroxyurea, spermine NONOate and DETA NONOate that release nitric oxide (NO). Our investigations indicate that B. pseudomallei are killed by NO in a concentration and time-dependent fashion. The cytoxicity of this diatomic radical against B. pseudomallei depends on both the culture medium and growth phase of the bacteria. Rapidly growing, but not stationary phase, B. pseudomallei are readily killed upon exposure to the NO donor spermine NONOate. NO also has excellent antimicrobial activity against anaerobic B. pseudomallei. In addition, persistent bacteria highly resistant to most conventional antibiotics are remarkably susceptible to NO. Sublethal concentrations of NO inhibited the enzymatic activity of [4Fe–4S]-cofactored aconitase of aerobic and anaerobic B. pseudomallei. The strong anti-B. pseudomallei activity of NO described herein merits further studies on the application of NO-based antibiotics for the treatment of melioidosis. [Copyright &y& Elsevier]

Abstract: Bifidobacteria are probiotic microorganisms that are widely used in the food industry. With the aim of using of Petrifilm™ Aerobic Count (AC) plates associated with selective culture media, aliquots of sterile skim milk were inoculated separately with four commercial cultures of bifidobacteria. These cultures were plated by both the conventional method and Petrifilm™AC, using the culture media NNLP and ABC. The cultures were incubated under anaerobiosis at 37 °C for 24, 48 and 72 h. No significant differences (p > 0.05) were observed between the obtained counts at 48 and 72 h. Bifidobacteria counts in ABC were usually higher than in NNLP, independent of the plating method. Subsequently, fermented milk was prepared with a Streptococcus thermophilus strain, and aliquots were inoculated with the same bifidobacteria. Then, the fermented milks were submitted to microbiological analysis for bifidobacteria enumeration using the same culture media and methodologies previously described, incubated under anaerobiosis at 37 °C for 48 h. Again, bifidobacteria counts in ABC were higher than in NNLP, with significant differences for some cultures (p < 0.05). The counts obtained by both methodologies presented significant correlations (p < 0.05). The results indicate the viability of Petrifilm™AC as an alternative method for bifidobacteria enumeration when associated to specific culture media, specially the ABC. [Copyright &y& Elsevier]

Abstract: Uptake of external sterols in the yeast Saccharomyces cerevisiae is a multistep process limited to anaerobiosis or heme deficiency. It includes crossing the cell wall, insertion of sterol molecules into plasma membrane and their internalization and integration into intracellular membranes. We applied the fluorescent ergosterol analog dehydroergosterol (DHE) to monitor the initial steps of sterol uptake by three independent approaches: fluorescence spectroscopy, fluorescence microscopy and sterol quantification by HPLC. Using specific fluorescence characteristics of DHE we showed that the entry of sterol molecules into plasma membrane is not spontaneous but requires assistance of two ABC (ATP-binding cassette) pumps – Aus1p or Pdr11p. DHE taken up by uptake-competent hem1ΔAUS1PDR11 cells could be directly visualized by UV-sensitive wide field fluorescence microscopy. HPLC analysis of sterols revealed significant amounts of exogenous ergosterol and DHE (but not cholesterol) associated with uptake-deficient hem1Δaus1Δpdr11Δ cells. Fluorescent sterol associated with these cells did not show the characteristic emission spectrum of membrane-integrated DHE. The amount of cell-associated DHE was significantly reduced after enzymatic removal of the cell wall. Our results demonstrate that the yeast cell wall is actively involved in binding and uptake of ergosterol-like sterols. [ABSTRACT FROM AUTHOR]

Abstract: Genome-based Flux Balance Analysis (FBA) and steady-state isotopic-labeling-based Metabolic Flux Analysis (MFA) are complimentary approaches to predicting and measuring the operation and regulation of metabolic networks. Here, genome-derived models of Escherichia coli (E. coli) metabolism were used for FBA and 13C-MFA analyses of aerobic and anaerobic growths of wild-type E. coli (K-12 MG1655) cells. Validated MFA flux maps reveal that the fraction of maintenance ATP consumption in total ATP production is about 14% higher under anaerobic (51.1%) than aerobic conditions (37.2%). FBA revealed that an increased ATP utilization is consumed by ATP synthase to secrete protons from fermentation. The TCA cycle is shown to be incomplete in aerobically growing cells and submaximal growth is due to limited oxidative phosphorylation. An FBA was successful in predicting product secretion rates in aerobic culture if both glucose and oxygen uptake measurement were constrained, but the most-frequently predicted values of internal fluxes yielded from sampling the feasible space differ substantially from MFA-derived fluxes. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate culture media and methodologies for isolation and detection of lactic acid bacteria (LAB) capable to produce bacteriocin-like substances. Samples of milk and cheese were pour plated on de Mann-Rogosa-Sharpe agar (MRS) and Kang-Fung-Sol agar (KFS) (both at 35 °C/48 h, under anaerobiosis), from which 389 and 256 LAB cultures were selected. The antagonistic activity of them was evaluated using the spot-on-the-lawn and two culture media: brain-heart infusion agar with catalase (BHI + C) and M17 (both at 35 °C/24 h). The proteinaceous nature of the antagonistic cultures was verified using: spot-on-the-lawn (MRS, 25 °C/24 h, under anaerobiosis) and well-diffusion (cultures amplified on modified MRS broth at 25 °C/24 h, and then neutralized using NaOH). Listeria monocytogenes ATCC 7644 was used as indicator. A larger number of antagonist cultures were isolated from MRS (83 by M17 and 65 by BHI + C) in comparison to KFS (24 by M17 and 15 by BHI + C). The spot-on-the-lawn identified a higher frequency of LAB capable of producing bacteriocin-like substances. MRS was considered to be the best culture media for the isolation of LAB capable to produce bacteriocin-like substances, activity that was better identified using the spot-on-the-lawn methodology. [Copyright &y& Elsevier]

Abstract: In fungi, the velvet gene, or veA, is involved in the regulation of diverse cellular processes, including control of asexual and sexual development as well as secondary metabolism. This global regulator is conserved in numerous fungal species. Interestingly, in Aspergilli, where most of the studies on veA have been carried out, this gene has been described to mediate development in response to light. In recent years the knowledge of this important regulatory system has expanded through the use of Aspergillus nidulans as a model organism, and through the study of veA orthologs across fungal genera. This review includes information on the current understanding of veA function and its mechanism of action. The fact that veA has only been found in fungi, together with advances in the elucidation of the veA mechanism, might be useful in designing future control strategies to decrease the detrimental effects of fungi while enhancing those qualities that are beneficial. [Copyright &y& Elsevier]

Abstract: The posterior cingulate cortex (PCC) is the brain region displaying the earliest sign of energy hypometabolism in patients with amnestic mild cognitive impairment (MCI) who develop Alzheimer’s disease (AD). In particular, the activity of the mitochondrial respiratory enzyme cytochrome oxidase (C.O.) is selectively inhibited within the PCC in AD. The present study is the first experimental analysis designed to model in animals the localized cortical C.O. inhibition found as the earliest metabolic sign of early-stage AD in human neuroimaging studies. Rats were used to model local inhibition of C.O. by direct injection of the C.O. inhibitor sodium azide into the PCC. Learning and memory were examined in a spatial holeboard task and brains were analyzed using quantitative histochemical, morphological and biochemical techniques. Behavioral results showed that sodium azide-treated rats were impaired in their memory of the baited pattern in probe trials as compared to their training scores before treatment, without non-specific behavioral differences. Brain analyses showed that C.O. inhibition was specific to the PCC, and sodium azide increased lipid peroxidation, gliosis and neuron loss, and lead to a network functional disconnection between the PCC and interconnected hippocampal regions. It was concluded that impaired memory by local C.O. inhibition in the PCC may serve to model in animals a metabolic lesion similar to that found in patients with amnestic MCI and early-stage AD. This model may be useful as an in vivo testing platform to investigate neuroprotective strategies to prevent or reduce the amnestic effects produced by posterior cingulate energy hypometabolism. [Copyright &y& Elsevier]

Abstract: The mitogen-activated protein kinase (MAPK) cascade regulates changes in gene transcription by transmitting extracellular stimuli from the plasma membrane to the cell nucleus and has an important role to play in organismal responses to environmental stresses. The activities of MAPKs were investigated in the marine gastropod mollusk, Littorina littorea, a species that tolerates both extracellular freezing and long term oxygen deprivation. In-gel kinase assays revealed the presence of two MAPKs in foot muscle and hepatopancreas, a 42 and a 115kDa protein. Immunoblot analysis showed that both were MAPK proteins and that one was the periwinkle homologue of p42ERK2. Size exclusion chromatography confirmed the 115kDa size of the novel snail MAPK and its role as the dominant MAPK activity in foot muscle. In-gel kinase assays, immunoblotting with phospho-specific ERK antibody, as well as kinase activity profiles from hydroxyapatite chromatography demonstrated that p115 MAPK kinase activity was increased in foot muscle in response to in vivo freezing or anoxia exposures. The results suggest a role for this novel kinase in environmental stress response. [Copyright &y& Elsevier]

Abstract: The aim of the present work was to evaluate the effect of thermal and anaerobic treatments on physiological and biochemical parameters in a variety of tomatoes (Lycopersicon esculentum Mill. cv. Colt 45). Treatments applied to mature green tomatoes were: (A) heat treatments by water immersion at 42°C for 30min (HS30′) or for 60min (HS60′); or by air at 38°C for 72h (HS72h); and (B) anaerobic treatments carried out at 20°C under humidified nitrogen atmosphere for 3 days (ANA3d) or 6 days (ANA6d). After treatments, fruits were stored at 2 or 14°C. Parameters evaluated were: colour, total acidity, major organic acids, firmness, and ethanol and acetaldehyde concentration. Anaerobic and long-term heat shock treatments inhibited colour development irrespective of storage temperature. Air heat treatment reduced tritratable acidity by increasing malic acid metabolism. Anaerobic treatments induced ethanol accumulation, which could be reversed during storage for the short treatment (3 days), but not for the longer treatment (6 days). Acetaldehyde concentration was increased by anaerobic treatments, but also by immersion in hot water for 60min, which would produce a “low-aerobic” environment. [Copyright &y& Elsevier]

Abstract: Indoleamine 2,3-dioxygenase (EC 1.13.11.42) is a heme-containing dioxygenase which catalyzes the first and rate-limiting step in the major pathway of l-tryptophan catabolism in mammals. Much attention has recently been focused on the dioxygenase because this metabolic pathway is involved not only in a variety of physiological functions but also in many diseases. In this review, the discovery and unique catalytic properties of dioxygenase are described first, and then the recent findings regarding the dioxygenase-initiated tryptophan metabolism are summarized, with special emphasis on the detrimental role of dioxygenase in side effects of interferon-γ and interleukin-12 (by systemic tryptophan depletion), the escape of malignant tumors from immune surveillance (by immunosuppression caused by tryptophan depletion), several neurodegenerative disorders including Alzheimer’s disease (by an aberrant production of neurotoxin, quinolinic acid), and age-related cataract (due to “Kynurenilation,” a novel post-translational modification of lens proteins with tryptophan-derived UV filters). [Copyright &y& Elsevier]

Abstract: A general trend of supramolecular chemistry is the building of mesoscopic-oriented nanotubes. When the typical radius of the channel almost fits the mean supramolecular cross-sectional radius, the guest supramolecule is ultraconfined in the channel. In that case, only rotational disorder around the channel axis is allowed. For sufficiently low temperatures, we expect this 2D disorder to be static on the NMR timescale, and it should reflect the local symmetry of the channels. In this article, we show that experiments performed with deuterium single crystal solid-state NMR as a function of rotation around the channel axis may lead to important information concerning the static orientational disorder of the confined supramolecules. Using an inversion method with Tikhonov regularization and a positivity constraint, that also takes into account of the nonideal pulse sequence response, the orientational probability density can be obtained from 1D experiments performed at different angles, even for significant disorder. As a first step, the method is validated on four different theoretical distributions. It is then applied to 2H NMR single crystal experiments performed on an archetype of parallel channels intergrowth compounds: selectively deuterated 1,10-decanedicarboxylic diacids in hydrogenated urea channels. The diacids form one-dimensional infinite hydrogen-bonded chains ultraconfined in urea linear channels. [Copyright &y& Elsevier]

Actinobacillus pleuropneumoniae is the causative agent of an economically significant form of porcine pleuropneumonia. This bacterium produces four distinct RTX toxins (ApxI–ApxIV) that play a key role in its pathogenesis, but further characterization of these hemolytic toxins is needed to identify the environmental signals and genes that affect their production during infection. In this report, we examined the effect of oxygen limitation on the production of ApxI and ApxII, the two RTX toxins that are produced by all highly virulent strains in North America. Batch cultures of ApxI- and ApxII-producing strains were grown in heart infusion broth supplemented with NAD, and samples were prepared throughout the growth curve. We compared batch cultures with normal oxygen levels to those that were maintained in an oxygen-depleted state. ApxI and ApxII hemolytic activity were nearly identical under both growth conditions. The level of toxin activity was confirmed by examination of extracellular ApxI concentrations and apxII mRNA levels. In addition, toxin activity examined on blood agar plates grown aerobically or anaerobically showed no significant difference. These results have important implications for the disease state where high-density growth is likely to result in local anaerobic or microaerophilic environments. [Copyright &y& Elsevier]

For the growth of several strictly anaerobic microorganisms, cysteine is the preferred reducing agent because of its low toxicity, but cysteine reduces media only slowly, making it inconvenient if the medium is needed immediately. A culture medium employed to cultivate ruminal anaerobic bacteria supplied with cysteine achieved the desired degree of anaerobiosis (measured spectrophotometrically by the bleaching of the indicator, resazurin) in considerably less time when exposed to high light intensity from a halogen lamp. The effect of light intensity on time to reduce media was quadratic; tubes kept under no illumination (dark) took more than 12 h to become colorless while tubes kept under normal laboratory light, took more than 2 h. On the other hand, media exposed to high light intensity (equivalent to a regular 100 W bulb lamp) became completely bleached in less than 20 min. Separate experiments demonstrated a direct correlation between the photocatalytic effect on medium reduction and a decrease in dissolved O2 content. However, media gassing with CO2 is still required, as the photocatalytic reaction requires semi-reduced conditions. A comparison of growth parameters for five species of ruminal bacteria cultivated in media prepared under high light vs normal light conditions showed no differences, indicating no adverse affect of cysteine catalysed medium reduction on growth. Aside from this benefit, other procedures such as extensive heating, cooling, evacuation and degassing with O2-free gases can be eliminated, thereby further reducing the time required for media preparation. Thus, use of high light intensity on cysteine/resazurin containing media greatly accelerated the establishment of anaerobic conditions, so that the media can be used almost immediately. [Copyright &y& Elsevier]

Abstract: We describe the application and evaluation of a widely available commercial jar as an anaerobic container suitable for the growth of a wide variety of anaerobes. A system for generating stable anaerobiosis was developed by combining standard anaerobic environment generators with Click-Clack jars produced by Click-Clack Ltd. (http://www.clickclack.com). This system was simple, reliable, and reduced capital outlay on anaerobic jars by at least an order of magnitude. [Copyright &y& Elsevier]

Abstract: Tsetse flies have a highly regulated and defined microbial fauna made of 3 bacterial symbionts (obligate Wigglesworthia glossinidia, commensal Sodalis glossinidius and parasitic Wolbachia pipientis) in addition to a DNA virus (Glossina pallidipes Salivary gland Hypertrophy Virus, GpSGHV). It has been possible to rear flies in the absence of either Wigglesworthia or in totally aposymbiotic state by dietary supplementation of tsetse’s bloodmeal. In the absence of Wigglesworthia, tsetse females are sterile, and adult progeny are immune compromised. The functional contributions for Sodalist are less known, while Wolbachia cause reproductive manupulations known as cytoplasmic incompatibility (CI). High GpSGHV virus titers result in reduced fecundity and lifespan, and have compromised efforts to colonize flies in the insectary for large rearing purposes. Here we investigated the within community effects on the density regulation of the individual microbiome partners in tsetse lines with different symbiotic compositions. We show that absence of Wigglesworthia results in loss of Sodalis in subsequent generations possibly due to nutritional dependancies between the symbiotic partners. While an initial decrease in Wolbachia and GpSGHV levels are also noted in the absence of Wigglesworthia, these infections eventually reach homeostatic levels indicating adaptations to the new host immune environment or nutritional ecology. Absence of all bacterial symbionts also results in an initial reduction of viral titers, which recover in the second generation. Our findings suggest that in addition to the host immune system, interdependencies between symbiotic partners result in a highly tuned density regulation for tsetse’s microbiome. [Copyright &y& Elsevier]

Autotrophic anaerobic ammonium oxidation (Anammox) is a biological process in which Planctomycete-type bacteria combine ammonium and nitrite to generate nitrogen gas. Both substrates can exert inhibitory effects on the process, causing the decrease of the specific activity of the biomass and the loss of the stable operation of reactors. The aim of the present work is to evaluate these effects in short- and long-term experiments. The short-term effects were carried out with two different types of Anammox biomass, biofilm on inorganic carriers and flocculent sludge. The effects of ammonium on both kinds of biomass were similar. A decrease of the Specific Anammox Activity (SAA) of 50% was observed at concentrations about 38 mg NH3-N·L−1, while 100 mg NH3-N·L−1 caused an inhibition of 80%. With regards to nitrite, the SAA was not affected at concentrations up to 6.6 μg HNO2-N·L−1 but it suffered a decrease over 50% in the presence of 11 μg HNO2-N·L−1 in the case of the biofilm. The flocculent biomass was much less resistant and its SAA sharply decreased up to 30% of its initial value in the presence of 4.4 μg HNO2-N·L−1. The study of the long-term effects was carried out in lab-scale Sequencing Batch Reactors (SBR) inoculated with the biofilm biomass. Concentrations up to 20 mg NH3-N·L−1 showed no effects on either reactor efficiency or biomass activity. However, when free ammonia concentrations reached values between 35 and 40 mg NH3-N·L−1, the operation turned unstable and the efficiency was totally lost. Nitrous acid concentrations around 1.5 μg HNO2-N·L−1 caused a loss of the efficiency of the treatment and a destabilization of the system. However, a total restoration of the SAA was observed after the stoichiometric feeding was applied to the SBR. [Copyright &y& Elsevier]