Our observation of a decline in the incidence of hepatotoxic events over the years suggests that a cumulative

toxic effect is unlikely. The representativeness of our study population for all NNRTI-using patients might be a point of discussion. After all, patients who develop (severe) toxicity in the first 3 years of therapy are less likely to continue using NNRTIs. learn more However, our short-term outcomes did not differ significantly from those reported by Brück et al. [2] and Palmon et al. [3]. In those cohorts of all patients starting an NNRTI-based regimen, severe toxicity rates of 1.7% and 1.1%, respectively, were observed, compared with 1.4% in the first year in our cohort. Regarding moderate hepatotoxicity, the incidence in our group was actually slightly higher than the incidence reported by Brück et al. (4.9% vs. 3.1%, respectively). Because of the retrospective design of the study, we were not always able to obtain complete biochemical data and information regarding the use of other potentially hepatotoxic medication (e.g. prescribed by

buy LBH589 the patient’s general practitioner or over-the-counter drugs) and excessive alcohol use. We also cannot exclude the possibility that some of the LEEs were side effects of the nucleoside reverse transcriptase inhibitor (NRTI) backbone. The number of patients with an HBV or HCV coinfection was low; this raises the question of whether our results would have been the same if this group had been larger. In summary, long-term NNRTI use was not associated

with a higher risk of clinically significant liver toxicity in our group of patients who had not discontinued their therapy within the first 3 years of treatment. There does not seem to be a long-term cumulative hepatotoxic effect of these antiretrovirals. “
“Objectives The aim of the study was to evaluate the possible effect of hepatitis C virus (HCV) coinfection on the viroimmunological outcomes of HIV-1 infection. Methods A cross-sectional study of 805 patients with active HCV infection receiving or not receiving antiretroviral therapy (ART) was carried out. Results A number of parameters were significantly associated with undetectable HIV-1 viral load in univariate analyses, Amisulpride such as age, toxic habits, CD4 cell count, liver test results, HCV viral load and ART. However, only current ART (P<0.0001), CD4 cell count (P<0.0001), age (P=0.004) and current injecting drug use (P=0.02) were independently associated with undetectable viral load in multivariate analysis. None of the many HCV- and liver fibrosis-related parameters analysed showed a significant association with HIV-1 viral load or CD4 cell count in multivariate analyses, with the exception of the annual fibrosis progression index which almost reached statistical significance in the subgroup of ART-untreated patients (P=0.06) and was inversely predictive of CD4 cell count in the whole group (P=0.007).

Our observation of a decline in the incidence of hepatotoxic events over the years suggests that a cumulative

toxic effect is unlikely. The representativeness of our study population for all NNRTI-using patients might be a point of discussion. After all, patients who develop (severe) toxicity in the first 3 years of therapy are less likely to continue using NNRTIs. Selleckchem Trametinib However, our short-term outcomes did not differ significantly from those reported by Brück et al. [2] and Palmon et al. [3]. In those cohorts of all patients starting an NNRTI-based regimen, severe toxicity rates of 1.7% and 1.1%, respectively, were observed, compared with 1.4% in the first year in our cohort. Regarding moderate hepatotoxicity, the incidence in our group was actually slightly higher than the incidence reported by Brück et al. (4.9% vs. 3.1%, respectively). Because of the retrospective design of the study, we were not always able to obtain complete biochemical data and information regarding the use of other potentially hepatotoxic medication (e.g. prescribed by

selleck chemicals the patient’s general practitioner or over-the-counter drugs) and excessive alcohol use. We also cannot exclude the possibility that some of the LEEs were side effects of the nucleoside reverse transcriptase inhibitor (NRTI) backbone. The number of patients with an HBV or HCV coinfection was low; this raises the question of whether our results would have been the same if this group had been larger. In summary, long-term NNRTI use was not associated

with a higher risk of clinically significant liver toxicity in our group of patients who had not discontinued their therapy within the first 3 years of treatment. There does not seem to be a long-term cumulative hepatotoxic effect of these antiretrovirals. “
“Objectives The aim of the study was to evaluate the possible effect of hepatitis C virus (HCV) coinfection on the viroimmunological outcomes of HIV-1 infection. Methods A cross-sectional study of 805 patients with active HCV infection receiving or not receiving antiretroviral therapy (ART) was carried out. Results A number of parameters were significantly associated with undetectable HIV-1 viral load in univariate analyses, Tangeritin such as age, toxic habits, CD4 cell count, liver test results, HCV viral load and ART. However, only current ART (P<0.0001), CD4 cell count (P<0.0001), age (P=0.004) and current injecting drug use (P=0.02) were independently associated with undetectable viral load in multivariate analysis. None of the many HCV- and liver fibrosis-related parameters analysed showed a significant association with HIV-1 viral load or CD4 cell count in multivariate analyses, with the exception of the annual fibrosis progression index which almost reached statistical significance in the subgroup of ART-untreated patients (P=0.06) and was inversely predictive of CD4 cell count in the whole group (P=0.007).

“
“Dr Senckenbergische Anatomie, Institute of Anatomy II, Goethe University, Frankfurt and Main, Germany Ablating the cochlea causes total sensory deafferentation of the cochlear nucleus. Over the first postoperative week, degeneration of the auditory nerve and its

synaptic terminals in the cochlear nucleus temporally overlaps with its re-innervation by axon collaterals of medial olivocochlear neurons. At the same time, astrocytes increase in size and density. We investigated the time courses of the expression of ezrin, polysialic acid, matrix metalloprotease-9 and matrix metalloprotease-2 within these astrocytes during the first week following cochlear ablation. All four proteins are known to participate in degeneration, regeneration, or Erlotinib supplier both, following injury of the central nervous system. In a next step, stereotaxic injections of kainic acid were made into the ventral nucleus of the trapezoid body prior to cochlear ablation to destroy the neurons that re-innervate

the deafferented cochlear nucleus by axon collaterals developing growth-associated protein 43 immunoreactivity. This experimental design see more allowed us to distinguish between molecular processes associated with degeneration and those associated with re-innervation. Under these conditions, astrocytic growth and proliferation showed an unchanged deafferentation-induced pattern. Similarly, the distribution and amount of ezrin and matrix metalloprotease-9 in astrocytes after cochlear ablation developed in the same way as under cochlear ablation alone. In sharp contrast, the astrocytic expression of polysialic acid and matrix metalloprotease-2

normally invoked by cochlear ablation collapsed when re-innervation of the cochlear nucleus was inhibited by lesioning medial olivocochlear neurons with kainic acid. In conclusion, re-innervation, including axonal growth and synaptogenesis, seems to prompt astrocytes to recompose their molecular profile, paving the way for tissue reorganisation after nerve degeneration and loss of synaptic contacts. “
“Dysfunction of the orexin/hypocretin neurotransmitter system causes the sleep disorder narcolepsy, characterized by intrusion of rapid eye movement (REM) sleep-like events into normal wakefulness. The sites where orexins act to suppress REM sleep are incompletely understood. 2-hydroxyphytanoyl-CoA lyase Previous studies suggested that the lateral pontomesencephalic tegmentum (lPMT) contains an important REM sleep inhibitory area, and proposed that orexins inhibit REM sleep via orexin type 2 receptors (OxR2) in this region. However, this hypothesis has heretofore not been tested. We thus performed bilateral injection of small interfering RNAs (siRNAs) targeting Ox2R into the lPMT on two consecutive days. This led to a approximately 30% increase of time spent in REM sleep in both the dark and light periods for the first 2 days after injection, with a return to baseline over the next two post-injection days.

Overall, all three technologies can be used for genome and transcriptome sequencing. Other applications aimed at RNA-seq of single cells (Tang et al., 2009) are eagerly awaited, but not yet described for bacteria and are

not commercially available. As indicated previously, high-throughput CX-4945 solubility dmso sequencing of cDNA libraries has the potential to study transcription at the single nucleotide level and hence yield much more detail on RNA transcripts present in a population of microbial cells. However, when compared with eukaryotic RNA, working with bacterial RNA has always been a challenge. Unlike eukaryotic mRNA, most bacterial mRNAs do not have a poly-A tail (Deutscher, 2003), and hence cannot be isolated from other RNA sources by hybridization to immobilized poly-T. Furthermore, bacterial RNA preparations learn more usually contain up to 80% rRNA and tRNA (Condon, 2007), and to add insult to injury, bacterial mRNA often has a very short half-life and hence can be highly unstable (Deutscher, 2003; Condon, 2007). Hence, it is not surprising that high-throughput sequencing of the transcriptome of a cell (RNA-seq or mRNA-seq)

was first described for eukaryotic cells, including the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe (Nagalakshmi et al., 2008; Wilhelm et al., 2008), mouse organs and embryonic stem cells (Cloonan et al., 2008; Mortazavi et al., 2008), human cell lines (Sultan et al., 2008) and the plant Arabidopsis thaliana (Lister et al., 2008). In these studies, transcriptome sequencing was highly informative,

and allowed for investigation of levels of transcripts as well as (alternative) splicing events. More information on RNA-seq in eukaryotic organisms can be found in recent reviews (Wang et al., 2009; Wilhelm & Landry, 2009). Figure 1 outlines the basic steps involved in generating cDNA libraries for high-throughput sequencing of microbial transcriptomes, and the subsequent analysis of these. So far, all papers describing the use of high-throughput sequencing for bacterial transcriptomics have specified using the optional enrichment methods, usually PAK5 based on depletion of tRNA and/or rRNA (Passalacqua et al., 2009; Perkins et al., 2009; Yoder-Himes et al., 2009). Size selection has also been used for the removal of mRNA and rRNA (Liu et al., 2009), although this is a potentially risky approach because this could remove long noncoding or antisense RNA species, as reported in Listeria and Bacillus (Rasmussen et al., 2009; Toledo-Arana et al., 2009). After sequence reads are mapped onto the genome sequence, these are usually visualized by generating histograms of reads on the annotated genome sequence, using a freely available software like artemis (Carver et al., 2008) or the Affymetrix Integrated Genome Browser (http://www.affymetrix.

Overall, all three technologies can be used for genome and transcriptome sequencing. Other applications aimed at RNA-seq of single cells (Tang et al., 2009) are eagerly awaited, but not yet described for bacteria and are

not commercially available. As indicated previously, high-throughput this website sequencing of cDNA libraries has the potential to study transcription at the single nucleotide level and hence yield much more detail on RNA transcripts present in a population of microbial cells. However, when compared with eukaryotic RNA, working with bacterial RNA has always been a challenge. Unlike eukaryotic mRNA, most bacterial mRNAs do not have a poly-A tail (Deutscher, 2003), and hence cannot be isolated from other RNA sources by hybridization to immobilized poly-T. Furthermore, bacterial RNA preparations Adriamycin clinical trial usually contain up to 80% rRNA and tRNA (Condon, 2007), and to add insult to injury, bacterial mRNA often has a very short half-life and hence can be highly unstable (Deutscher, 2003; Condon, 2007). Hence, it is not surprising that high-throughput sequencing of the transcriptome of a cell (RNA-seq or mRNA-seq)

was first described for eukaryotic cells, including the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe (Nagalakshmi et al., 2008; Wilhelm et al., 2008), mouse organs and embryonic stem cells (Cloonan et al., 2008; Mortazavi et al., 2008), human cell lines (Sultan et al., 2008) and the plant Arabidopsis thaliana (Lister et al., 2008). In these studies, transcriptome sequencing was highly informative,

and allowed for investigation of levels of transcripts as well as (alternative) splicing events. More information on RNA-seq in eukaryotic organisms can be found in recent reviews (Wang et al., 2009; Wilhelm & Landry, 2009). Figure 1 outlines the basic steps involved in generating cDNA libraries for high-throughput sequencing of microbial transcriptomes, and the subsequent analysis of these. So far, all papers describing the use of high-throughput sequencing for bacterial transcriptomics have specified using the optional enrichment methods, usually selleck chemical based on depletion of tRNA and/or rRNA (Passalacqua et al., 2009; Perkins et al., 2009; Yoder-Himes et al., 2009). Size selection has also been used for the removal of mRNA and rRNA (Liu et al., 2009), although this is a potentially risky approach because this could remove long noncoding or antisense RNA species, as reported in Listeria and Bacillus (Rasmussen et al., 2009; Toledo-Arana et al., 2009). After sequence reads are mapped onto the genome sequence, these are usually visualized by generating histograms of reads on the annotated genome sequence, using a freely available software like artemis (Carver et al., 2008) or the Affymetrix Integrated Genome Browser (http://www.affymetrix.

Aforementioned

differences were statistically significant (P < 0.005), as shown in Fig. 5. Live planktonic cell stimulation exhibited higher IL-6 concentration than biofilm phase bacteria (P < 0.05). No differences were observed on IL-6 using either phase of formalin-fixed bacteria. Also, formalin-fixed planktonic cell stimulation exhibited higher IL-1β concentration than biofilm phase bacteria (P < 0.005). No differences were observed on IL-1β using either phase of live bacteria. In contrast, biofilm bacteria induced higher amounts of IL-8, IL-13 and GM-CSF (P < 0.005). http://www.selleckchem.com/products/VX-809.html Incubation of MDMs with live biofilm phase bacteria resulted in lower amounts of the proinflammatory cytokines TNFα, IL-1β and IL-6, as well as IL-12p40 and IL-12p70 as compared to planktonic phase bacteria (Table 1). Biofilm formation is considered a major virulence factor of S. epidermidis. It is well accepted that bacterial pathogens growing in a biofilm are recalcitrant to the action of most antibiotics and are resistant to the innate immune system (Fey, 2010). Our results demonstrate that although biofilm phase bacteria exhibit higher degrees Selleckchem Tofacitinib of adherence and phagocytosis, they are more resistant to killing by human macrophages than their planktonic counterparts.

We could assume that biofilm organization promotes phagocytosis either because of interaction of specific bacterial moieties with specific macrophage receptors or because of the fact that upon interaction with biofilm fragments, macrophages are forced to engulf an increased number of bacterial cells firmly attached to each other. Although hydrophilicity of bacteria because of of the presence of exopolysaccharides has generally been correlated with decreased phagocytosis by PMNs, a previous report showed increased adherence and increased phagocytosis of a biofilm-producing strain (RP62A; ATCC35984), as compared to its phenotypic variant, nonbiofilm-producing RP62A-NA, upon interaction with human neutrophils despite its lower hydrophobicity (Heinzelmann et al., 1997). In contrast, other studies indicate that S. epidermidis’ extracellular polysaccharide

moiety decreases phagocytic activity of murine peritoneal macrophages in a dose-dependent manner that is independent of interferon activation (Shiau & Wu, 1998). Also, phagocytosis by human PMNs was found to be significantly increased in a PIA-negative mutant strain as compared to the wild-type strain (Vuong et al., 2004). Consistent with this are studies in J774A.1 murine macrophages where phagocytic uptake of mature biofilm-forming S. epidermidis 1457 was attenuated compared to its isogenic mutant 1457-M10. This effect could be completely abrogated upon disaggregation of the biofilm by mechanical disruption or ultrasound treatment supporting a role for PIA and biofilm in leucocyte evasion (Schommer et al., 2011).

With recent developments in

viral metagenomics, characterization of viral bioaerosol communities provides an opportunity for high-impact future research. However, there remain significant challenges for the study of viral bioaerosols compared with viruses in other matrices, such as water, the human gut, and soil. Collecting enough biomass is essential for successful metagenomic analysis, but this is a challenge with viral bioaerosols. Herein, we provide a perspective on the importance of studying viral bioaerosols, the challenges of studying viral community structure, and the potential opportunities for improvements in methods to study viruses in indoor and outdoor air. “
“Ribosomal genes are strongly regulated dependent on growth phase in all organisms, but this regulation is poorly understood in Archaea. Moreover, very little is known about growth phase-dependent gene regulation in Archaea. SSV1-based Cisplatin purchase lacS reporter gene constructs containing the Sulfolobus 16S/23S rRNA gene core promoter, the TF55α core promoter, or the native lacS promoter were tested in Sulfolobus solfataricus cells lacking the lacS gene. The 42-bp 16S/23S rRNA gene and 39-bp TF55α core promoters are sufficient for gene expression in S. solfataricus. However, only gene expression driven by the 16S/23S rRNA gene core promoter is dependent on the culture growth phase.

This is the smallest known regulated promoter in Sulfolobus. To our knowledge, this is the first study to show growth phase-dependent rRNA gene regulation in Archaea. Regulation of rRNA transcription is critical for cellular life and has been investigated buy MS-275 extensively in Bacteria and Eukarya, where it is tightly regulated by multiple and overlapping mechanisms including growth phase-dependent regulation (Nomura, 1999; Schneider et al., 2003). However, little is known about rRNA transcriptional regulation in Archaea. rRNA genes in Archaea are frequently linked, containing the 23S rRNA gene downstream of the 16S rRNA gene (http://archaea.ucsc.edu). Sulfolobus solfataricus and Sulfolobus shibatae contain single 16S/23S rRNA gene operons that have been previously studied in vivo and in vitro (Reiter et al., 1990; Qureshi et al.,

1997). The basal transcriptional apparatus of Archaea is similar to that of Eukaryotes (reviewed in Bartlett, 2005). Megestrol Acetate However, most putative transcriptional regulators are homologues of bacterial transcription factors and appear to act similarly, by either preventing or facilitating the assembly of the transcriptional preinitiation complex (Bell, 2005; Peng et al., 2011). How the regulators function in vivo is unclear partly due to the lack of efficient genetic systems for many Archaea. The majority of transcriptional regulation analyses in Archaea, particularly thermoacidophilic Archaea, have been performed in vitro. This is changing with the development of genetic tools for S. solfataricus (Wagner et al., 2009), Sulfolobus islandicus (Peng et al.

With recent developments in

viral metagenomics, characterization of viral bioaerosol communities provides an opportunity for high-impact future research. However, there remain significant challenges for the study of viral bioaerosols compared with viruses in other matrices, such as water, the human gut, and soil. Collecting enough biomass is essential for successful metagenomic analysis, but this is a challenge with viral bioaerosols. Herein, we provide a perspective on the importance of studying viral bioaerosols, the challenges of studying viral community structure, and the potential opportunities for improvements in methods to study viruses in indoor and outdoor air. “
“Ribosomal genes are strongly regulated dependent on growth phase in all organisms, but this regulation is poorly understood in Archaea. Moreover, very little is known about growth phase-dependent gene regulation in Archaea. SSV1-based learn more lacS reporter gene constructs containing the Sulfolobus 16S/23S rRNA gene core promoter, the TF55α core promoter, or the native lacS promoter were tested in Sulfolobus solfataricus cells lacking the lacS gene. The 42-bp 16S/23S rRNA gene and 39-bp TF55α core promoters are sufficient for gene expression in S. solfataricus. However, only gene expression driven by the 16S/23S rRNA gene core promoter is dependent on the culture growth phase.

This is the smallest known regulated promoter in Sulfolobus. To our knowledge, this is the first study to show growth phase-dependent rRNA gene regulation in Archaea. Regulation of rRNA transcription is critical for cellular life and has been investigated JQ1 in vivo extensively in Bacteria and Eukarya, where it is tightly regulated by multiple and overlapping mechanisms including growth phase-dependent regulation (Nomura, 1999; Schneider et al., 2003). However, little is known about rRNA transcriptional regulation in Archaea. rRNA genes in Archaea are frequently linked, containing the 23S rRNA gene downstream of the 16S rRNA gene (http://archaea.ucsc.edu). Sulfolobus solfataricus and Sulfolobus shibatae contain single 16S/23S rRNA gene operons that have been previously studied in vivo and in vitro (Reiter et al., 1990; Qureshi et al.,

1997). The basal transcriptional apparatus of Archaea is similar to that of Eukaryotes (reviewed in Bartlett, 2005). Tau-protein kinase However, most putative transcriptional regulators are homologues of bacterial transcription factors and appear to act similarly, by either preventing or facilitating the assembly of the transcriptional preinitiation complex (Bell, 2005; Peng et al., 2011). How the regulators function in vivo is unclear partly due to the lack of efficient genetic systems for many Archaea. The majority of transcriptional regulation analyses in Archaea, particularly thermoacidophilic Archaea, have been performed in vitro. This is changing with the development of genetic tools for S. solfataricus (Wagner et al., 2009), Sulfolobus islandicus (Peng et al.

A strong relationship between baseline caries prevalence and the 4-year increment

was observed (OR = 7.38; 95% CI: 3.78–14.41). Conclusions.  The results suggest that in relatively low-caries conditions the school-based use of xylitol/maltitol or erythritol/maltitol lozenges would not have additional caries-preventive effect when compared with comprehensive prevention. “
“A traumatic injury to the primary dentition can cause damage to the germ of the permanent successor. As a clinical consequence a dilaceration with root deformation, malpositioning and disturbances of eruption can occur. Surgical repositioning of such a dislocated crown of a developing tooth can be a treatment option. A four year old patient was referred to our clinic because of a mobile upper primary central incisor and a radiographically visible displaced dental crown. Her history revealed a traumatic dental injury one year ago. Radiologic examination confirmed an inflammatory BIBF 1120 chemical structure root resorption on tooth 61 and a dislocation of the developing tooth 21. In order

to avoid further displacement due to the inflammation, 61 was extracted at the buy Forskolin first appointment. A radiographic image 7 months later showed no improvement in the malposition of tooth 21. Therefore tooth 21 was surgically repositioned into its correct position. Follow-up over 3 years confirmed a continued root development and a full eruption of 21 in its correct position. Early diagnosis and early treatment of a dislocated permanent tooth germ is essential to allow a favorable outcome. Surgical repositioning can be successful in avoiding later malpositioning of the permanent teeth. “
“International Journal of Paediatric Dentistry 2013; 23: 207–215 Background.  Amylase There is a lack of clinical trials on paediatric dental sedation. Aim.  We investigated whether young children’s behaviour improves during dental treatment with oral ketamine/midazolam compared with midazolam alone or no sedation. Design.  Healthy children under 36 months of age, presenting early childhood caries were randomly assigned to receive protective stabilization

plus: combined oral midazolam (0.5 mg/kg) and ketamine (3 mg/kg) (MK), or oral midazolam (1.0 mg/kg) (MS), or no sedative (PS). One observer scored children’s behaviour using the Ohio State University Behavior Rating Scale (OSUBRS) at determined points in a dental exam (no sedative) and treatment session. Data were analysed using nonparametric bivariate tests. Results.  Forty-one children were included. In the dental exam session, the sum of OSUBRS scores was similar for the three groups (P = 0.81). In the treatment session, the MK produced more cooperative behaviour than MS and PS (P = 0.01), longer sessions (P = 0.04), and a pattern of homogeneous OSUBRS scores from the reception area (before sedative administration) to the end of the session (P = 0.06). No immediate and post-discharge side effects were observed in groups MK and MS. Conclusions.

Given that the Calvin–Benson–Bassham (CBB) cycle enzymes downstream of RuBisCO require reducing equivalents, it is an advantage that Hg2+ inhibits RuBisCO, shutting GKT137831 nmr down the CBB cycle, making reducing equivalents available to mercuric reductase. We anticipate that enzymes of the Quayle pathway were inhibited (given the lack of carbon assimilation), forcing oxidation

of formaldehyde and formate to CO2 to generate reducing equivalents to meet requirements of the detoxification. It should be noted that hexulose-3-phosphate synthase (EC 4.1.2.43) – a key enzyme in the Quayle pathway – in M. capsulatus (Bath) is inhibited by Hg2+ at 100 μM (Ferenci et al., 1974). Cytochrome c oxidase was unable to reduce Hg2+ under the assay conditions employed PFT�� cost – either with cytochrome c550 or with ferrocyanide as the cofactor

– the specific activities were zero in both cases. The specific activity of an apparent mercuric reductase (± SEM; n = 7) was 352 (±18) nmol NADH oxidized min−1 (mg protein)−1 or 16 (±2) nmol NADPH oxidized min−1 (mg protein)−1, suggesting that this enzyme may be present. In the literature, NADPH is the more usual cofactor; however, a number of species contain an NADH-dependent enzyme (Gachhui et al., 1997; Meissner & Falkinham, 1984). Blastp interrogation of the GenBank™ database shows that the closest matches to the M. capsulatus (Bath) MerA are those derived from genome sequences of Alicycliphilus denitrificans BC (YP_004126461), Acidovorax sp. JS42 (YP_985596) and Delftia acidovorans SPH-1 (YP_001561514) with 83%, 83% and 81% identity, respectively. It is interesting to note that these are members PLEKHM2 of the Betaproteobacteria, rather than the Gammaproteobacteria. The presence of apparent mercuric reductase activity in M. capsulatus Bath extracts not previously exposed to mercury (II)

indicates that the enzyme is constitutively expressed. RNA microarray data concerning M. capsulatus (Bath) demonstrates that merA and other predicted mercury detoxification genes are expressed during growth as performed here (A. Khalifa, personal communication). We conclude that it is likely that a constitutive, NADH-dependent mercuric reductase is active in M. capsulatus (Bath), with NADH provided at the expense of methane oxidation, although further experiments with inhibitors or knock-out mutants are required to determine whether the merA gene is required for mercury (II) reduction. In the ‘emergency situation’ of mercury (II) exposure, the cell ‘prioritises’ the oxidation of methane to CO2, halting carbon assimilation, presumably to make more NADH available to remove the ion as rapidly as possible by way of a fundamental survival mechanism. Although enzymes of the Quayle pathway and CBB cycle were inhibited – as demonstrated by the complete lack of 14C assimilation – the primary methane oxidation enzymes remained active for over 30 min.