2d). As shown in Fig. 4h, the triple mutant NopT1-GCC was not capable of causing cell death in tobacco following transient expression by Agrobacterium as the wild-type protein did. This result suggests that the putative palmitoylation sites may be more important than myristoylation for plant plasma membrane association and the subsequent cell death in tobacco. To investigate whether the NopT1 autoprocessing is required to reveal the embedded acylation sites, we created another mutant (NopT1-DKM)

by substituting residues D47, K48, and M49 with alanines (Fig. 2d). In this mutant, both acylation sites were intact, while Akt inhibitor the amino acids immediately preceding the putative check details NopT1 autocleavage site were modified. This mutant was inactive in eliciting cell death in tobacco (Fig. 4i). To further test whether the mutant proteins NopT1-GCC and NopT1-DKM are autoprocessed, we expressed them in E. coli and analyzed the purified proteins by SDS-PAGE and Western blotting. The NopT1-DKM was completely resistant to autocleavage (Fig. 2c), suggesting that the residues D47, K48, and M49 are required for autoprocessing of the N-terminal region. In contrast, the protein mutated in residues G50, C52, and C53 (NopT1-GCC) still shows autocleavage (Fig. 2c). It is interesting

to note that the wild-type NopT1 was very rapidly processed in E. coli, and we were able to detect the full-length protein only when short times of induction (e.g. 2–4 h) were chosen. In contrast, the full-length protein of the GCC mutant was still detectable in substantial amounts upon induction of protein expression for 12 h in E. coli. Although these results indicate that mutation in the G50, C52, and

C53 residues partially affects the autoproteolytic activity of NopT1, significant autocleavage activity is observed for NopT1-GCC protein. Together, the results suggest that autoprocessing of NopT1 is required to unmask its putative acylation sites. In this study, we Forskolin in vitro demonstrated for the first time that NopT1, but not NopT2, of B. japonicum elicits cell death in plants tested. Both proteins possess cysteine protease activity that is essential for the cell death–eliciting activity in the case of NopT1. Many members of the YopT/AvrPphB effector family have been shown to possess cysteine protease activity (Shao et al., 2002; López-Solanilla et al., 2004), although some of them are not autoprocessed or acylated (Dowen et al., 2009). In plant symbiotic bacteria, three genes encoding YopT family members have been found: one in Rhizobium NGR234, named nopT (Dai et al., 2008), and two in B. japonicum (nopT1 and nopT2). Multiple proteases of the YopT family can be found in a single strain, for example, in Pseudomonas syringae pv.

05; however, Rgp/cell and Kgp/ext in Fig. 3a were statistically different; P<0.01), but significantly low in 83K7 (8–36% of those of 83K5; P<0.01). These results show that the function of Sov is affected by the subtle find protocol structural difference between 83K6 and 83K7 (the C-terminals

are –Phe–His–His–His–His–His–His and –Phe–Arg–His–His–His–His–His–His), but not by the dramatic structural difference between wild-type W83 and 83K6 (the C-terminals are –Phe–Arg–Phe–Asn–Leu–Thr–Gln and –Phe–His–His–His–His–His–His). We suspect that a steric effect or the length of the C-terminal portion of Sov influences its function. Nevertheless, the expression of histidine-tagged Sov in 83K7 (Fig. 4a, lane 2) and 83K6 (lane 3) was similar to that in 83K5 (lane 1), suggesting that the hypoactivity of Sov renders the primary defect in the gingipain activity of 83K7. Finally, we clarified whether the C-terminal portion of Sov locates to the extracellular milieu. We investigated see more the effect of anti-histidine-tag IgG on the secretion of Arg-gingipains

by 83K5 and 83K6, both of which express histidine-tagged Sov. As a polar-effect control, we used 83K4, which carries the erm cassette like 83K5, but expresses Sov (Saiki & Konishi, 2007). The Arg-gingipain activities in the extracellular fractions were comparable among 83K4, 83K5, and 83K6 (P<0.05). As shown in Fig. 4b, the secretion of Arg-gingipains by 83K5 and 83K6 cells was significantly reduced (decreased to 84% and 79% of that by 83K4; P<0.01) by rabbit anti-histidine-tag IgG (50 μg mL−1). By contrast, the secretion of Arg-gingipains by 83K4, 83K5, and 83K6 cells was slightly affected by rabbit anti-histidine-tagged IgG (5 μg mL−1; P<0.05) or bovine IgG (50 μg mL−1; P<0.05). Although the inhibition

by anti-histidine-tag IgG was weaker than by anti-Sov32-177:2408-2499 antiserum acetylcholine (Fig. 1c), the results showed that the C-terminal portion of Sov may protrude into the extracellular milieu and may be involved in the modulation of Sov function. Sov contains a putative signal sequence, suggesting that Sov is a secreted protein (Saiki & Konishi, 2007). However, Sov shows no other conserved structural feature. Our investigation provides evidence that Sov is localized to the outer membrane and possibly participates in the secretion of gingipains. Nelson et al. (2007) reported that Flavobacterium johnsoniae SprA, a homologue of Sov, is likely an outer membrane protein. SprA is required for the gliding motility of F. johnsoniae (Nelson et al., 2007); however, the function of SprA has not yet been determined. In P. gingivalis, which is nonmotile, Sov appears to play a role in protein secretion. Perhaps F. johnsoniae SprA functions in the secretion of proteins required for gliding motility. We found that a five-residue section (Phe2495–Gln2499) in the C-terminal portion of Sov is essential for its function; this section may protrude into the extracellular milieu.

, 2001). C/EBP β, especially LAP1 and LAP2, can be phosphorylated at several sites by many different protein kinases, such as mitogen-activated GSK2126458 solubility dmso protein kinases, protein kinase A, protein kinase C, glycogen synthase kinase 3, and calcium/calmodulin-dependent protein kinases, with different effects on its transcriptional activity, depending on the phosphorylation site (Mahoney et al., 1992; Wegner et al., 1992; Trautwein et al., 1993, 1994; Piwien-Pilipuk et al., 2001, 2002). In particular, whereas phosphorylation

of rat C/EBP β by protein kinase A, protein kinase C or glycogen synthase kinase 3 on Ser240, which is located in the DNA-binding domain, has been reported to attenuate DNA binding and induce nuclear export, Ser105 phosphorylation of LAP isoforms is a key determinant of its transactivation capacity (Trautwein et al., 1993, 1994; Buck et al., 1999; Piwien-Pilipuk et al., 2001, GSK2118436 solubility dmso 2002). We therefore evaluated C/EBP β phosphorylation on Ser105 as a marker of transcriptional activity for this transcription factor. By using an antibody that specifically recognizes C/EBP β phosphorylated on Ser105, we observed that LAP1 is phosphorylated on Ser105 only in the nuclear compartment, implying

its transcriptional activation. From our co-immunoprecipitation experiments, we determined that LAP1 is essentially present in CGNs in its sumoylated form, both in the cytoplasm and in the nucleus, Idelalisib cell line and that the phosphorylated form is only nuclear and is only detected when neurons are kept in pro-survival conditions. The SUMOs serve as modifiers, exerting their effect by becoming conjugated to target proteins and stabilizing them (reviewed

by Lieberman, 2004). Sumoylation provides a rapid and efficient way to modulate the subcellular localization, activity and stability of a wide variety of protein substrates (Dorval & Fraser, 2007). C/EBPs, including C/EBP β, are well-known targets of SUMOs, which control their transcriptional activity by releasing, in rats, the inhibitory action of a conserved inhibitory domain that is a target for lysine sumoylation (Kim et al., 2002). Concerning C/EBP β isoforms, both LAP1 and LAP2 are potential targets of SUMO-2/3, but only LAP1 has been demonstrated to be conjugated to SUMO-2/3, as confirmed by our present results in CGNs. C/EBP β sumoylation has been shown to regulate its transcriptional activity, without influencing its subcellular localization (Eaton & Sealy, 2003). When CGNs were shifted to K5 medium to induce apoptosis, we observed a decrease in the LAP1 level and an increase in the LIP level in the nuclear compartment, and a decrease in the LAP2 level in the cytosolic fraction. Concomitantly, p-(Ser105)-LAP1 disappeared from the nuclear fraction.

Strains were cultured in L-broth or on LB agar plates supplemented with ampicillin (100 μg mL−1), chloramphenicol (20 μg mL−1) or kanamycin (50 μg mL−1) as appropriate. Plasmid pCP20 (Cherepanov & Wackernagel, Regorafenib cell line 1995) was obtained from the Coli Genetic Stock Center, Yale; pBADλRed was originally from Richards (2005). The source of the kanamycin resistance marker for Red recombinase mutagenesis was pCC065 (unpublished), a pUC19 derivative

containing an aph(3′)-Ia gene flanked by FRT recognition sites for the FLP flippase recombination enzyme (Cherepanov & Wackernagel, 1995). Genomic islands were deleted by λRed

recombinase-mediated insertion of a selectable marker essentially as described previously (Mo et al., 2006). The strains generated and primers used for amplification of the kanamycin cassette are shown in Tables 1 and 2. Briefly, a kanamycin resistance cassette flanked by FRT sites was amplified from pCC065 by the PCR using primers with at least 40 bp of homology to the DNA flanking the region to be deleted, purified and electroporated into SEn Thirsk harbouring the pBADλRed helper plasmid following induction with 0.2% learn more L(+) arabinose. Transformants were selected on LB agar plates containing kanamycin and cured of pBADλRed by serial passage in the absence of ampicillin.

Ampicillin-negative colonies were selected using MAST-ID™ Intralactam circles (Mast Group ltd., Bootle, UK). Mutants were confirmed by PCR and sequencing (not shown) and transduced using bacteriophage P22int isometheptene into fresh Thirsk to reduce the likelihood of second-site mutations being responsible for any observed phenotype. The antibiotic cassette was removed by FLP-catalysed excision using the temperature-sensitive plasmid pCP20 (Cherepanov & Wackernagel, 1995), which was then cured by passage at 37 °C in the absence of selection. Mutations were confirmed by the PCR and sequencing (not shown). Motility as assessed on LB plates with 0.4% agar and exponential growth rate in L-broth at 37 °C using a Bioscreen C automated plate reader (Oy Growth Curves Ab ltd., Finland) were indistinguishable from the wild type (not shown).

As noted in the GSK-3 signaling pathway Introduction, the direct evidence available excludes neither possibility because it is clear that Ygf Z dimerizes readily, at least ex vivo (Teplyakov et al., 2004), and that at least some Ygf Z exists with a free thiol inside plant cells (Hägglund et al., 2008). It will not be possible to show definitively whether Ygf Z works as a disulphide-bonded dimer or as a thiol monomer (or both) until the action of Ygf Z can be reconstituted in vitro. However, the balance of present evidence favours the thiol monomer, as summarized

in the following. Firstly, there is reason to suspect that Ygf Z dimer formation is unphysiological. Thus, the three-dimensional structure of the dimer suggests that the intermolecular C228-C228′ disulphide bridge might not be functionally relevant because the dimer interface formed by multiple nonspecific van der Waals interactions is not extensive and contains none of the conserved dodecapeptide motif residues except C228 (Teplyakov et al., 2004). Moreover, in our pilot tests, recombinant Ygf Z isolated from E. coli was 65% monomeric even when no reductants were added (not shown). Secondly, E. coli Ygf Z has been shown to have a

redox-active cysteine, this website i.e. a free thiol group, in vivo (Takanishi et al., 2007). Besides C228, Ygf Z has one other cysteine residue, C63, and it was not shown which is the redox-active one (Takanishi et al., 2007). However, the crystal structure places C63 at the C-terminal end of a β-strand in domain B, which makes the sulfhydryl solvent inaccessible, and C228 in an exposed surface loop between two α-helices (α9 and α10) of the Ygf Z monomer (Teplyakov et al., 2004), suggesting that the latter is the redox-active residue. Finally, Ygf Z belongs to the same protein family as sarcosine oxidase, dimethylglycine oxidase and the T-protein of the glycine-cleavage complex. All of these proteins

use tetrahydrofolate to accept a one-carbon (formaldehyde) unit (Teplyakov et al., 2004; Scrutton & Leys, 2005), and the one structurally closest to Ygf Z – the T-protein – acts on a thiol adduct of the one-carbon unit, borne by the H-protein of the complex (Douce et al., 2001). Formaldehyde is a ubiquitous metabolite that spontaneously forms harmful adducts with reactive protein side chains (Metz et al., Vitamin B12 2004), and it has been proposed that Ygf Z removes such inhibitory adducts from Fe/S enzymes by transferring the formaldehyde moiety to tetrahydrofolate (Waller et al., 2010). In such an enzyme repair mechanism, a cysteine thiol could logically play a go-between role, analogous to that of the active thiol in the glycine-cleavage complex, by binding formaldehyde after its removal from an Fe/S enzyme and before its transfer to tetrahydrofolate. A repair role for Ygf Z is not incompatible with the proposal that Ygf Z facilitates the breakdown of plumbagin (Lin et al.

Biochemical as well as molecular tools were used to characterize the cultured actinomycetes. Mucus of four healthy individuals of the coral A. digitifera were collected from Hare Island (9°12′N latitude and 79°5′E longitude), the largest island in the Gulf of Mannar, Tamil Nadu, India. Coral mucus was collected using sterile cotton swabs (Guppy & Bythell, 2006). The coral surface mucus layer was swabbed using sterile cotton swabs. Mucus samples of c. 1 cm2 coral surface area were taken with these swabs. After swabbing, the swabs were immediately placed in sterile polypropylene tubes. Seawater samples were collected with 50-mL sterile tubes that were opened underwater adjacent to the

same corals. Sediment samples were collected from right below the corals. All samples were transported to the laboratory (in about 4-h time) in ice-cold condition and were plated for isolation of bacteria. HSP inhibitor review The mucus swab samples were transferred to sterile

tubes with 1 mL of autoclave-sterilized seawater, in a sterile hood. The cotton swabs were vigorously vortexed to suspend the bacteria in seawater (Guppy & Bythell, 2006). Actinomycetes were isolated using standard serial dilution and plating techniques in BYL719 price triplicate on starch casein agar supplemented with actidione (40 μg mL−1) (Himedia Laboratories, Mumbai, India) found to inhibit the growth of fungi (Goodfellow & Williams, 1988) and nalidixic acid (10 μg mL−1) (Himedia Laboratories), which inhibits the bacteria capable of swarming without affecting the growth of actinomycetes (Nonomura & Hayakawa, 1988). Actinomycetes colonies were recognized these on the basis of morphological and physiological characteristics following directions given by the International Streptomyces Project (Shirling & Gottlieb, 1966). Morphological characteristics were studied under a light microscope after

15 days of growth on oatmeal agar (ISP3) (Shirling & Gottlieb, 1966). Actinomycetes counts were recorded as CFUs and expressed as CFU per 1 cm2 of coral surface area for mucus and tissue. Culturable actinomycetes from seawater and sediment were recorded as CFU mL−1 (of seawater) and CFU g−1 (of sediment), respectively. The isolated actinomycetes were identified by performing various biochemical tests according to the Bergey’s manual and Lampert et al. (2006). Carbohydrate tests were performed using the HiCarbohydrate kit (Himedia Laboratories). The sensitivity of the actinomycetes to various antibiotics was determined after incubation for 24–48 h at 30 °C on ISP2 (International Streptomyces Project) agar (Himedia Laboratories). Total genomic DNA was extracted using a modified cetyltrimethylammonium bromide–NaCl protocol. For each isolate, a loopful of mycelium and spores was scraped from colonies grown on Starch Casein Agar (SCA) and resuspended in TE buffer as described previously (Zin et al., 2007). As suggested by Stach et al.

In conclusion, we found that ZDV was able to inhibit and change the growth of gingival tissue when the drug was added at either day 0 or day 8 of raft growth. ZDV increased the expression of PCNA, cyclin A and cytokeratin 10. The expression of cytokeratins 5 and 6 and involucrin was decreased in ZDV-treated rafts. Together these results

indicate that ZDV deregulated the growth, differentiation and proliferation profiles in human gingival raft tissue. These results are consistent with the finding of oral complications in patients undergoing long-term HAART. Additional studies will be needed to determine the exact mechanism by which ZDV is exerting its effect. We thank Lynn Budgeon for technical assistance in preparing Ixazomib histological slides. This work was supported by NIDCR grant DE018305 to CM. “
“HIV status has commonly been found to affect the serum lipid profile. The aim of this study was to determine the effect of HIV infection on lipid metabolism; such information may be used to improve the management of HIV-infected patients. Samples were collected from December 2005 to May 2006 at Yaounde University Teaching Hospital, Yaounde, Cameroon. Lipid parameters were obtained using colorimetric 5-FU solubility dmso enzyme assays, while low-density lipoprotein cholesterol (LDLC) values were calculated using the formula of Friedewald et al. (1972) and atherogenicity index by total cholesterol

(TC)/high-density lipoprotein cholesterol (HDLC) and LDLC/HDLC ratios. HIV infection was most prevalent in subjects aged 31 to 49 years. Most of the HIV-positive patients belonged to Centers for Disease Control and Prevention categories

B (43.0%) and C (30.23%). Compared with control subjects, patients with CD4 counts<50 cells/μL had significantly lower TC (P<0.0001) and LDLC (P<0.0001) but significantly higher triglyceride (TG) values (P<0.001) and a higher atherogenicity index for TC/HDLC (P<0.01) and HDLC/LDLC (P=0.02); patients with CD4 counts of 50–199 cells/μL had significantly lower TC (P<0.001) and significantly higher TG values (P<0.001); patients with CD4 counts of 200–350 cells/μL had significantly higher TG (P=0.003) and a higher atherogenicity index for TC/HDLC (P<0.0002) and HDLC/LDLC (P=0.04); and those with CD4 counts >350 cells/μL had a higher atherogenicity index Cyclin-dependent kinase 3 for TC/HDLC (P<0.0001) and HDLC/LDLC (P<0.001). HDLC was significantly lower in HIV-positive patients irrespective of the CD4 cell count. Lipid parameters were also influenced by the presence of opportunistic infections (OIs). HIV infection is associated with dyslipidaemia, and becomes increasingly debilitating as immunodeficiency progresses. HDLC was found to be lower than in controls in the early stages of HIV infection, while TG and the atherogenicity index increased and TC and LDLC decreased in the advanced stages of immunodeficiency. HIV infection is a major public health problem worldwide. It affects 33.2 million people globally, of whom 24.5 million are in Africa [1].

The establishment of the etiology of low egg viability may ultimately lead to

a treatment modality to increase the hatching rate of this critically endangered species. Indeed, recent reports demonstrated that bacteria (Awong-Jaylor et al., 2008) and the Selleckchem ATM inhibitor fungus, Fusarium solani (Sarmiento-Ramirez et al., 2010), were responsible for/associated with failed loggerhead sea turtle eggs, making it clear that egg-associated pathogens are an area of concern for leatherback turtles. The Acinetobacter sp. HM746599 bacteria are available from the Culture Collection, University Gothenburg, Göteborg, Sweden (CCUG-600049), and from the Agricultural Research Service Culture Collection, Peoria, IL (NRRL-B-59471). We would like to thank http://www.selleckchem.com/products/gsk1120212-jtp-74057.html Dr Richard Facalam

at the CDC, Washington, DC, for the analysis of several characteristics of the bacteria and Dr David Collins of the University of Reading, UK, for the initial partial sequencing of the rRNA gene in the bacteria. “
“The genome sequence of the organohalide-respiring bacterium Dehalogenimonas lykanthroporepellensBL-DC-9T contains numerous loci annotated as reductive dehalogenase homologous (rdh) genes based on inferred protein sequence identity with functional dehalogenases of other bacterial species. Many of these genes are truncated, lack adjacent regulatory elements, or lack cognate genes coding for membrane-anchoring proteins typical of the functionally characterized active reductive dehalogenases of organohalide-respiring bacteria. To investigate the expression patterns of the rdh genes in D. lykanthroporepellensBL-DC-9T, oligonucleotide primers were designed to uniquely target 25 rdh genes present in the genome as well as four putative regulatory genes. RNA extracts from cultures of strain BL-DC-9T actively dechlorinating three different electron acceptors, 1,2-dichloroethane, 1,2-dichloropropane, and 1,2,3-trichloropropane were reverse-transcribed and subjected to PCR amplification using rdh-specific primers. Nineteen rdh gene

transcripts, including Edoxaban 13 full-length rdhA genes, six truncated rdhA genes, and five rdhA genes having cognate rdhB genes were consistently detected during the dechlorination of all three of the polychlorinated alkanes tested. Transcripts from all four of the putative regulatory genes were also consistently detected. Results reported here expand the diversity of bacteria known to simultaneously transcribe multiple rdh genes and provide insights into the transcription factors associated with rdh gene expression. “
“The binary toxin ‘Photorhabdus insect-related’ proteins (PirAB) produced by Photorhabdus luminescens have been reported to possess both injectable and oral activities against a range of insects.

The analysis of the published information and the sequences deposited in the public databases

allowed a first classification of these plasmids into a Apoptosis Compound Library nmr restricted number of groups according to the proteins involved in the initiation of replication, plasmid partition and conjugation. The sequence comparisons demonstrated that the plasmids from sphingomonads encode for four main groups of replication initiation (Rep) proteins. These Rep proteins belong to the protein superfamilies RepA_C (Pfam 04796), Rep_3 (Pfam 01051), RPA (Pfam 10134) and HTH-36 (Pfam 13730). The ‘degradative megaplasmids’ pNL2, pCAR3, pSWIT02, pCHQ1, pISP0, and pISP1, which code for genes involved in the degradation of aromatic hydrocarbons, carbazole, dibenzo-p-dioxin and γ-hexachlorocyclohexane, carry Rep proteins which either belong to the RepA_C- (plasmids

pNL2, pCAR3, pSWIT02), Rep-3- (plasmids pCHQ1, pISP0) or RPA-superfamily (pISP1). The classification of these ‘degradative megaplasmids’ into three groups is also supported by sequence comparisons selleckchem of the proteins involved in plasmid partition (ParAB) and the organization of the three genes on the respective plasmids. All analysed ‘degradative megaplasmids’ carry genes, which might allow a conjugative transfer of the plasmids. Sequence comparisons of these genes suggest the presence of at least two types of transfer functions, which either are closer related to the tra- or vir-genes previously described for plasmids from other sources. The sphingomonads represent a group of Alphaproteobacteria, O-methylated flavonoid which encompass in our days the genera Novosphingobium, Sphingobium, Sphingomonas, Sphingopyxis, Sphingosinicella, Sphingomicrobium, Sphingorhabdus and Parasphingopyxis. These genera share a number of phenotypic traits, such as the presence of sphingolipids in their outer membranes, the formation of usually yellow-pigmented colonies and a specific pattern of polyamines (Kämpfer et al., 2012; Uchida et al., 2012; Jogler et al., 2013). Sphingomonads have been

intensively studied during the last years because of their pronounced ability to degrade recalcitrant natural and xenobiotic compounds, such as various polycyclic aromatic hydrocarbons (PAHs), nonylphenols, sulphonated naphthalenes, chlorinated dibenzofurans and dibenzodioxins, carbazole, polyethylene glycols and different herbicides and pesticides (Stolz, 2009). It was shown in the last years that many sphingomonads possess (often several) plasmids and especially that rather large plasmids are common in this bacterial group. These large plasmids are commonly designated as ‘megaplasmids’ if their sizes exceed about 100 kbp (Basta et al., 2004, 2005; Aylward et al., 2013). These ‘megaplasmids’ often carry genes coding for degradative pathways, which are often found either on different replicons (as e.g.

The analysis of the published information and the sequences deposited in the public databases

allowed a first classification of these plasmids into a LGK974 restricted number of groups according to the proteins involved in the initiation of replication, plasmid partition and conjugation. The sequence comparisons demonstrated that the plasmids from sphingomonads encode for four main groups of replication initiation (Rep) proteins. These Rep proteins belong to the protein superfamilies RepA_C (Pfam 04796), Rep_3 (Pfam 01051), RPA (Pfam 10134) and HTH-36 (Pfam 13730). The ‘degradative megaplasmids’ pNL2, pCAR3, pSWIT02, pCHQ1, pISP0, and pISP1, which code for genes involved in the degradation of aromatic hydrocarbons, carbazole, dibenzo-p-dioxin and γ-hexachlorocyclohexane, carry Rep proteins which either belong to the RepA_C- (plasmids

pNL2, pCAR3, pSWIT02), Rep-3- (plasmids pCHQ1, pISP0) or RPA-superfamily (pISP1). The classification of these ‘degradative megaplasmids’ into three groups is also supported by sequence comparisons Selleckchem Pictilisib of the proteins involved in plasmid partition (ParAB) and the organization of the three genes on the respective plasmids. All analysed ‘degradative megaplasmids’ carry genes, which might allow a conjugative transfer of the plasmids. Sequence comparisons of these genes suggest the presence of at least two types of transfer functions, which either are closer related to the tra- or vir-genes previously described for plasmids from other sources. The sphingomonads represent a group of Alphaproteobacteria, Thymidine kinase which encompass in our days the genera Novosphingobium, Sphingobium, Sphingomonas, Sphingopyxis, Sphingosinicella, Sphingomicrobium, Sphingorhabdus and Parasphingopyxis. These genera share a number of phenotypic traits, such as the presence of sphingolipids in their outer membranes, the formation of usually yellow-pigmented colonies and a specific pattern of polyamines (Kämpfer et al., 2012; Uchida et al., 2012; Jogler et al., 2013). Sphingomonads have been

intensively studied during the last years because of their pronounced ability to degrade recalcitrant natural and xenobiotic compounds, such as various polycyclic aromatic hydrocarbons (PAHs), nonylphenols, sulphonated naphthalenes, chlorinated dibenzofurans and dibenzodioxins, carbazole, polyethylene glycols and different herbicides and pesticides (Stolz, 2009). It was shown in the last years that many sphingomonads possess (often several) plasmids and especially that rather large plasmids are common in this bacterial group. These large plasmids are commonly designated as ‘megaplasmids’ if their sizes exceed about 100 kbp (Basta et al., 2004, 2005; Aylward et al., 2013). These ‘megaplasmids’ often carry genes coding for degradative pathways, which are often found either on different replicons (as e.g.