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Chemical pesticides are still frequently overused to diminish such crop loss caused by biotic stress despite the threat to humans and the environment. Thus, it is urgent to find safer and more effective defense strategies. In this study, we report that caffeine, implanted through a transgenic approach, enhances resistance against variable biotic stresses in rice without fitness cost. Caffeine-producing rice (CPR) was generated by introducing three N-methyltransferase genes involved in the biosynthesis of caffeine in coffee plants. The CPR plants have no differences in morphology and growth compared to their wild-type counterparts, but they show strongly enhanced resistance to both bacterial leaf blight, rice blast, and attack of white-backed planthoppers. Caffeine acts as a repellent agent against rice pathogens. Moreover, caffeine triggers a series of Ca

Occult breast cancer is rare in practice. We studied the clinical outcomes of 5 occult breast cancers, including 2 with Luminal and 3 with non-Luminal subtypes, for which the primary site was not detected in the breast-by-breast MRI. The percentage of occult breast cancers that we encountered at our hospital was 0.11%. The mean age was 54 years. The Ki-67 labeling index value was 30% or higher for all the patients except one. Four patients were administered neoadjuvant chemotherapy and all but one patient received non-mastectomy and axillary dissection plus radiotherapy. We observed recurrent cases in one example each of the Luminal and HER2 subtypes, and both patients were less than 40 years old. The estimates of the probability of 5 year recurrence-free survival and 5 year overall survival were 40.0% and 66.7%, respectively. One recurrence case was a patient negative for ER and positive for HER2 wherein a breast cancer lesion appeared in the breast during post-treatment follow-up. Intrabreast relapse, which is itself rare in occult breast cancer, was observed 4 years postoperatively after standard treatment. Although there was no deviation according to subtype rate, the Ki-67 labeling index value was high and the prognosis was poor in our 5 cases.

Objectives: To assess the impact of the quantity of resources for breast and cervical cancer screening on the participation rates in screening in clinical settings in municipalities, as well as to clarify whether lack of resources impairs access to cancer screening in Japan.Methods: Of the 1,746 municipalities in 2010, 1,443 (82.6%) and 1,469 (84.1%) were included in the analyses for breast and cervical cancer screening, respectively. In order to estimate the effects of the number of mammography units and of gynecologists on the participation rates in breast and cervical cancer screening in clinical settings, multiple regression analyses were performed using the interaction term for urban municipalities.Results: The average participation rate in screening in clinical settings was 6.01% for breast cancer, and was 8.93% for cervical cancer. The marginal effect of the number of mammography units per 1,000 women was significantly positive in urban municipalities (8.20 percent point). The marginal effect of the number of gynecologists per 1,000 women was significantly positive in all municipalities (2.54 percent point) and rural municipalities (3.68 percent point).Conclusions: Lack of mammography units in urban areas and of gynecologists particularly in rural areas impaired access to breast and cervical cancer screening. Strategies are required that quickly improve access for the residents and increase their participation rates in cancer screening.

Virtualisation technology which can decrease the number of physical machines to use the resources effectively has become a research trend. Several methods of Live Migration (LM) for Virtual Machine (VM) Placement have been proposed. However, existing LM methods do not well take into account, such as transfer time and Random-Access Memory (RAM) usage of each VM. Considering this situation, we have already proposed a method of LM in case of “on-premise” system structure to balance the load of each physical server considering total RAM usage by VMs in a physical server and the bit transfer time proportional to Round-Trip Delay Time (RTT). Also, through a preliminary evaluation, we have shown that our method has a possibility to make the total processing time shorter. Based on this result, this paper revisits the proposal, evaluates it by giving additional conditions and shows its effectiveness.

Embryogenic calli were induced from leaf explants of coffee (Coffea canephora) on McCown's woody plant medium (WPM) supplemented with 5 μM N6–(2-isopentenyl)-adenosine (2-iP). These calli were co-cultured with Agrobacterium tumefaciens EHA101 harboring pIG121-Hm, containing β-glucuronidase (GUS), hygromycin phosphotransferase (HPT), and neomycin phosphotransferase II genes. Selection of putative transgenic callus was performed by gradual increase in hygromycin concentration (5, 50, 100 mg/l). The embryogenic calli surviving on medium containing 100 mg/l hygromycin showed a strong GUS-positive reaction with X-Gluc solution. Somatic embryos were formed from these putative transgenic calli and germinated on WPM medium with 5 μM 2-iP. Regenerated small plantlets with shoots and roots were transferred to medium containing both 100 mg/l hygromycin and 100 mg/l kanamycin for final selection of transgenic plants. The selected plantlets exhibited strong GUS activity in leaves and roots as indicated by a deep blue color. GUS and HPT genes were confirmed to be stably integrated into the genome of the coffee plants by the polymerase chain reaction.

Phylogenetic and taxonomic characterization was performed for a bacterium, designated strain Q-192T, isolated from the surface of the green macroalga Halimeda sp., collected from the subtropical Ishigaki Island, Japan. The isolate was a polysaccharide-producing, Gram-stain-negative, aerobic, rod-shaped, motile bacterium with a polar flagellum. The isolate was slightly halophilic, required Na+, Mg2+ and Ca2+ ions for growth, but did not require growth factors. The only isoprenoid quinone was ubiquinone-8.The major cellular fatty acids were C18 : 1ω7c, C16 : 0 and C14 : 0. The main hydroxy fatty acid was C10 : 0 3-OH. The DNA G+C content was 45.9 mol%. Phylogenetic analysis of 16S rRNA gene sequences placed the isolate in the class Gammaproteobacteria. The phylogenetically closest relatives with validly published names were Pseudomaricurvus alkylphenolicus KU41GT, Teredinibacter turnerae T7902T, Pseudoteredinibacter isoporae SW-11T and Simiduia agarivorans SA1T with sequence similarities of 94.5, 94.1, 93.7 and 93.6 %, respectively. The isolate was distinguished from members of these genera by a combination of DNA G+C content, chemotaxonomic characteristics (respiratory quinone system, fatty acid profile and polar lipid composition) and other phenotypic features. Based on phylogenetic, genotypic, chemotaxonomic and phenotypic characteristics, strain Q-192T is considered to represent a novel species of a new genus, for which the name Marinibactrum halimedae gen. nov., sp. nov. is proposed. The type strain of Marinibactrum halimedae is Q-192T ( = NBRC 110095T = NCIMB 14932T).

2-[(Trimethylsilyl)methyl]benzyl methanesulfonates react with potassium fluoride in the presence of a catalytic amount of 18-crown-6 at room temperature to give o-quinodimethanes, which are trapped with electron-deficient olefins to afford [4+2] cycloadducts in good yields.

Background Controversy surrounds the reliability of sentinel lymph node biopsy after primary systemic chemotherapy. In this study, we assessed axillary ultrasound for selecting patients most likely to optimally benefit from biopsy. Methods The study included 87 patients who received primary systemic chemotherapy and underwent a sentinel lymph node biopsy followed by axillary lymph node dissection. Lymph nodes >10 mm in diameter, irregularly swollen, round, and homogeneously hypoechoic without an echo-rich center were considered axillary ultrasound positive. Results In axillary ultrasound–negative patients before and after primary systemic chemotherapy, identification, sensitivity, and false-negative rates were 81%, 100%, and 0%, respectively. However, in patients whose lymph nodes converted from positive to negative after primary systemic chemotherapy, these values were 83%, 70.8%, and 29.2%, respectively. Conclusions Axillary ultrasound–negative patients before and after primary systemic chemotherapy were suitable for sentinel lymph node biopsy. Axillary ultrasound should be used during primary systemic chemotherapy and before surgery.

Objectives: We investigated the time course of the stromal cell-derived factor 1α (SDF1α) expression and behavior of intravenously administered bone marrow-derived stromal (BMS) cells in the urinary bladder of partial bladder outlet obstruction (PBOO) rats. Methods: Study 1: Recombinant SDF1α or saline was directly injected into the bladder wall of female rats followed by intravenous administration of BMS cells isolated from green fluorescent protein (GFP) transgenic rats. The bladder was examined with immunohistochemistry to determine whether SDF1α would enhance migration of BMS cells to the bladder. Study 2: Following surgery of PBOO or sham in female rats, bladders were removed on days 1–14, and expression of hypoxia inducible factor 1α (HIF1α) and SDF1α were examined with real-time polymerase chain reaction (PCR) to determine if PBOO preferentially increased their expression. Study 3: Female rats underwent PBOO or sham surgery followed by intravenous administration of GFP-positive BMS cells. Bladders were examined with immunohistochemistry on days 1–14 to determine whether BMS cells preferentially accumulated in the bladder. Results: BMS cells were accumulated in the injection site of SDF1α but not saline in the bladder. SDF1α and HIF1α increased at day 1 after PBOO compared to sham. More BMS cells accumulated in the bladder of PBOO on day 1, and some BMS cells expressed smooth muscle phenotypes by day 14. Conclusion: SDF1α induced with ischemia/hypoxia due to PBOO is implicated in the accumulation of BMS cells in the bladder and regeneration of the bladder for PBOO.

Catalytic asymmetric Diels–Alder reaction of α-amino-o-quinodimethane with α,β-unsaturated aldehydes was achieved with high diastereo- and enantioselectivities in the presence of l-proline, which acts as a promoter to generate the quinodimethane from the corresponding precursor as well as a chiral catalyst for the enantioselective Diels–Alder reaction.

A novel approach was introduced for breast surgery using the BiClamp, a new bipolar thermal energy device, to avoid complications and to shorten the time required for the dissection of the axillary lymph nodes.Thirty-six patients with early breast cancer were assessed. The surgical parameters were compared between the procedures performed using the BiClamp technique (n = 14) and conventional surgery with suture ligation (n = 22). The parameters included the operation time, blood loss, and discharge on the first postoperative day. In addition, each of those parameters was compared between the patients with a high body mass index (BMI) (22) and a low BMI (or =22). The sealed vessels were examined histologically and heat-associated morphological vessel wall alterations were evaluated.The operation time was significantly shorter in the BiClamp group than in the control group (P = 0.017, 90 +/- 18 vs 115 +/- 33 min). In addition, the blood loss in the BiClamp group tended to be smaller than in the control group, but the difference was not significant (P = 0.54, 61 +/- 47 vs 74 +/- 67 g). No other parameters showed any significant differences between the two groups.The BiClamp thermofusion technique was safe and useful in breast surgery involving axillary dissection.

Plants produce up to 100,000 secondary metabolites. One of their biological functions is self-denfese, and it is referred as chemical defense, directly and/or indirectly counteracting biotic and abiotic stresses. Alkaloids constitute 12% of total secondary metabolites, and some of them exhibit detrimental effects on living organisms. Caffeine (1,3,7-trimethylxanthine) is a member of purine alkaloids, and its exogenous application to plants at relatively high concentrations (0.01-0.1%) effectively repelled herbivores and pathogenic microbes. This allowed the construction of transgenic crops that endogenously produce caffeine to tolerate stresses. Experimentally, tobacco and chrysanthemum were successfully transformed with three distinct N-methyltranferases involved in the caffeine biosynthesis pathway. They produced 0.4-5 mug caffeine/g tissue (5 x 10(-4)%), this being three magnitudes lower than values found in caffeine-producing plants and in vitro experiments. Nevertheless, they exhibited strong repellence against pest insects, and high resistance to virus and bacterial infection. They also exhibited accelerated self-defense, as estimated by constitutive expression of defense-related genes, and by elevated production of salicylic acid, a critical signaling molecule for defense response. Since caffeine content was low in transgenic lines, observed effects might not be direct, but rather indirect. We presume that, as endogenously produced caffeine could be toxic, the host plants activated its own self-defense system, which commonly occurs regarding other stresses. Eventually the host became on standby to cope with a broad range of biotic stresses. The procedure resembles mammalian vaccination, in which antigen-antibody system is critical. We propose that plants can also be vaccinated as far as proper "antigenic" chemicals are expressed in planta.

Recent advanced imaging modalities such as positron emission tomography (PET) detect malignancies using 2-[18F]-fluoro-2-deoxy-D: -glucose (18-FDG) with high accuracy, and they contribute to decisions regarding diagnosis, staging, recurrence, and treatment response. Here, we report a case of false-positive metastatic lymph nodes that were diagnosed by PET/CT and ultrasonography in a 48-year-old breast cancer patient who had undergone mastectomy. The tumors, which were oval shaped and resembled lymph nodes, were detected by ultrasonography. PET/CT revealed high uptake of 18-FDG in the tumors. To investigate the proposed recurrence and to re-evaluate the biology of the recurrent tumors, a tumor was removed from the brachial plexus of the patient. Histological findings revealed it to be a schwannoma. All imaging modalities including PET/CT failed to distinguish benign tumors from metastatic lymph nodes in the brachial plexus. After resection of the schwannomas, the patient complained of a slight motor disorder of the second finger on the right hand. Hence, it is important to consider a false-positive case of lymph node metastasis in a breast cancer patient following mastectomy.

We report a case of metastatic breast cancer with leptomeninges and multiple bone metastases that showed an excellent response to the combination of trastuzumab and capecitabine; therapeutic effect was evaluated by MRI at follow-up. A 44-year-old woman underwent modified radical mastectomy in February 1997. In April 2003, a tumor at the right basis cerebri and multiple bone metastases were noted, and in October 2003, she underwent enucleation of the tumor. Histopathologically, the tumor was consistent with a basal skull metastasis from breast cancer. In March 2004, the patient began to experience pain, weakness, and paresthesia of both legs. She was diagnosed, with leptomeningeal metastasis (LM) from breast cancer using MRI. In December 2005, the combination of trastuzumab and capecitabine administered as sixth-line treatment was very effective for LM. Although it is generally very difficult to diagnose LM and assess the therapeutic effect with MRI, in this case, it was possible. To our knowledge, there has been no report in the literature describing the combination of trastuzumab and capecitabine for LM from breast cancer. Although the mechanism underlying the efficacy of this combination is still unknown, the treatment would be worth trying because of its few side effects in extensively treated patients with LM from breast cancer. To confirm the antitumor efficacy of trastuzumab and capecitabine, however, further investigations are required.

Caffeine is synthesized from the precursor xanthosine through three methylation and one nucleoside removal steps. Methylation is catalyzed by N-methyltransferases, designated as CaXMT1, CaMXMT1 and CaDXMT1, which, respectively, convert xanthosine into 7-methylxanthosine, 7-methylxanthine into 3,7-dimethylxanthine, and 3,7-dimethylxanthine into 1,3,7-trimethylxanthine (caffeine). In the present study, we examined their cytological and biochemical properties using fusion proteins with fluorescent proteins. All three enzymes were found to localize in cytosol as visualized by green fluorescence protein fusions. The possibility of dimer formation among these enzyme proteins was examined in vivo by transient expression of bimolecular fluorescence complementation of yellow fluorescent protein (YFP) using onion epidermal cell layers. Results showed that each enzyme protein formed a homo-dimer in cytosol as seen by a clear reconstituted YFP fluorescence. In addition, each enzyme also formed a hetero-dimer with each of the other two enzymes in cytosol. The biological significance of dimerization among structurally resembling methyltransferases involved in caffeine biosynthesis is discussed.

Details of the recently elucidated biosynthetic pathways of caffeine and related purine alkaloids are reviewed. The main caffeine biosynthetic pathway is a sequence consisting of xanthosine-->7-methylxanthosine-->7-methylxanthine-->theobromine-->caffeine. Genes encoding N-methyltransferases involved in three of these four reactions have been isolated and the molecular structure of N-methyltransferases investigated. Pathways for the catabolism of caffeine have also been studied, although there are currently no reports of enzymatic and genetic studies having been successfully carried out. Metabolism of purine alkaloids in species including Camellia, Coffea, Theobroma and Ilex plants is summarised, and evidence for the involvement of caffeine in chemical defense and allelopathy is discussed. Finally, information is presented on metabolic engineering that has produced coffee seedlings with reduced caffeine content, and transgenic caffeine-producing tobacco plants with enhanced disease resistance.

In vitro culture from seeds to full maturity of Cypripedium macranthos var. rebunense, one of the most endangered species in Japan, was studied. Immature seeds from wild plants germinated efficiently in Tsutsumi-Tomita medium and 1/3 strength Murashige-Skoog medium both supplemented with 1% sucrose. Formed protocorms were transferred onto the same Murashige-Skoog medium developed into seedlings, which were subjected to a cold-treatment. The seedlings were further successively cultured in artificial soils (Florialite and then Cryptomoss) under artificially controlled photoperiod and temperature conditions. After 7 years, fully matured plants successfully flowered. The genetic diversity of the wild colony of this orchid in Rebun Island was examined. Leaf samples randomly collected were subjected to random amplified polymorphic DNA analysis. Initially examined 31 samples were classified into independent 5 groups, indicating that the colony consists of genetically different individuals. This suggested that plants in the habitat are heterogenous as to the genetic structure. Introduction of artificially propagated plants with a similar genetic background to this habitat would match the genetic diversity of the existing population. The results of this study may be helpful in planning the rescue of other endangered plant species.

Biotic and abiotic-induced wounding is one of the severest stresses that plants suffer throughout the growing period. Upon injury, plants rapidly activates a set of genes, which encode diverse proteins to cope with damages. Screening such genes that were transcriptionally activated within 30 min after mechanical wounding in tobacco plants, we identified a particular clone encoding a multfunctional protein, and designated as NtMFP (Nicotiana tabacum multifunctional protein). The deduced polypeptide is constituted of 668 amino acids with an apparent molecular mass of 72.3 kDa, and bacterially expressed protein exhibited a clear b-oxidation activity. Fusion proteins with GFP were observed in cytosol, when expressed in onion epidermal cell layers. In addition to wounding, NtMFP transcripts were induced by tobacco mosaic virus infection, and by jasmonic acid treatments. When NtMFP was suppressed by the RNAi, transgenic tobacco showed dwarfism, early senescence and reduced expresstion of jasmonic acid-responsive genes. Multifunctional protein is generally considered to catalyze multiple steps of the fatty acid b-oxidation. It is also proposed to be involved in the b-oxidation step of jasmonic acid biosynthesis. The present results suggest the possibility that NtMFP commonly functions not only in fatty acid catabolism but also in jasmonic acid biosynthesis pathway.

ATPase associated with various cellular activities (AAA) proteins are commonly distributed among eukaryotes, and are involved in a multitude of cellular functions. NtAAA1 is one such example, being involved in pathogen response in tobacco plants. When its activity was suppressed in RNAi transgenic tobacco plants, an elevated resistance to the pathogenic bacterium Pseudomonas syringae was observed in comparison with the wild type. As AAA proteins function through interaction with specific partners, NtAAA1-interacting proteins were screened by the yeast two-hybrid assay, and one particular gene encoding a small GTPase, an ADP ribosylation factor, was identified and designated as NtARF. Its specific binding to NtAAA1 was confirmed by in vitro pull-down assay, and their interaction was predominant between active forms of NtARF and NtAAA1, each bound to GTP and ATP, respectively. Their physical interaction in vivo around the plasma membrane was shown by fluorescence resonance energy transfer assays, suggesting their role in membrane trafficking. Transgenic tobacco plants constitutively expressing NtARF under the control of a cauliflower mosaic virus 35S promoter exhibited spontaneous and wound-induced lesion formation, and enhanced resistance to pathogen attack. Expression of NtAAA1 in leaves of NtARF transgenic plants attenuated lesion and suppressed pathogen resistance. In wild-type tobacco plants, transcripts of NtAAA1 and NtARF could be induced by ethylene and salicylic acid, respectively. These results suggest that NtAAA1 balances plant resistance through suppression of NtARF, and that the molecular basis for the known antagonistic actions of ethylene and salicylic acid in defense response could be partly attributable to these two proteins.

A plastid-resident basic helix–loop–helix protein, previously identified in Nicotiana tabacum and designated as NtWIN4 (N. tabacum wound-induced clone 4), has been converted from a nuclear transcription repressor into a plastid-resident regulatory factor through replacement of the DNA-binding domain with a plastid transit sequence during evolution. N. tabacum is a natural amphidiploid plant derived from Nicotiana tomentosiformis and Nicotiana sylvestris and immunoblot staining using anti-NtWIN4 antibodies identified two protein species, a 26 kDa form and a 17 kDa form, in N. sylvestris, whereas only the 17 kDa form was found in N. tabacum. The 26 kDa protein is produced when translation starts from the first AUG codon of the mRNA and is predominantly localized in the cytoplasm and nucleus, whereas the 17 kDa protein is derived from a 24 kDa precursor protein, synthesized from the second AUG codon, and localizes only to plastids. Subsequent analyses revealed that the lengths of the mRNAs vary in the two plant species. One major form lacks the first AUG, while minor populations possess variable 5′-untranslated regions prior to the first AUG codon. Translation of the two types produces the 24 kDa and 26 kDa proteins respectively. In vitro translation assays indicated that initiation frequency from the first AUG codon is higher in mRNAs from N. sylvestris than from N. tabacum. In contrast, initiation from the second AUG codon was found to be equally efficient in mRNAs from both species. These results suggest that both mRNA populations and translation efficiency changed during the amphidiploidization responsible for generation of N. tabacum. This scheme could reflect a molecular mechanism of protein evolution in plants.

To examine the relationship between gene expression and DNA methylation, transcriptionally activated genes were screened in hypomethylated transgenic tobacco plants expressing an anti-DNA methyltransferase sequence. Among 16 genes initially identified, one clone was found to encode a glycerophosphodiesterase-like protein (NtGPDL), earlier reported to be responsive to aluminium stress. When detached leaves from wild type tobacco plants were treated with aluminium, NtGPDL transcripts were induced within 6 h, and corresponding genomic loci were demethylated at CCGG sites within 1 h. Direct bisulfite methylation mapping revealed that CG sites in coding regions were selectively demethylated, and that promoter regions were totally unmethylated regardless of the stress. Salt and low temperature treatments also induced similar demethylation patterns. Such effects could be attributable to oxidative stress, since reactive oxygen species generated by paraquat efficiently induced the same pattern of demethylation at coding regions. Pathogen infection induced neither transcripts nor genomic demethylation. These results suggested a close correlation between methylation and expression of NtGPDL upon abiotic stresses with a cause-effect relationship. Since DNA methylation is linked to histone modification, it is conceivable that demethylation at coding regions might induce alteration of chromatin structure, thereby enhancing transcription. We propose that environmental responses of plants are partly mediated through active alteration of the DNA methylation status.

Basic helix-loop-helix (bHLH) proteins constitute one of the most abundant types of transcription factor in both plants and animals. They are considered to be localized in the nucleus, but recent surveys have revealed two exceptions, NtWIN4 from tobacco and AtPTF1 from Arabidopsis, both reported to localize to plastids. Their specific subcellular localization was suggested to be the result of structural change, whose analysis might provide clues to understanding protein evolution. Consequently we performed comparative analyses on localization features of both NtWIN4 and AtPTF1 using GFP-tagged fusion proteins. While epifluorescence from NtWIN4-GFP was clearly observed in plastids, that from AtPTF1-GFP was unexpectedly seen only in nuclei. Subsequent transcription assays using a dual-luciferase system indicated that AtPTF1 possesses clear nuclear transcriptional repression activity. It is concluded that, in contrast to the previous paradigm, AtPTF1 is a nuclear transcriptional repressor, and therefore that NtWIN4 is the only non-nucleus resident bHLH protein.

In this paper we propose a snow sensor that detects presence of snow on road surface. Automatic threshold selection is one of the statistical image processing techniques and is effective way to divide image into some regions that have common properties. Using this method, we can detect snow from images containing pavement marking such as center line under various road conditions. Furthermore, we install the sensor on actual road and control a snow melting system. It is confirmed that the sensor works appropriately and reduces operating time of the snow melting system compared with the conventional snowfall sensor.

Cytosines in eukaryotic DNA is often methylated to yield 5-methylcytosines (m 5 C), which play an important role in controlling gene expression. This is referred as DNA methylation, and its status dynamically changes during plant growth by active methylation and demethylation. DNA glycosylases have been known to possess base excision DNA repair activity, and an Arabidopsis enzyme, ROS1 (Repressor of Silencing 1), was recently shown to exhibit m 5 C DNA glycosylase activity. We isolated and characterized four genes encoding ROS1-like proteins from tobacco plants (Nicotiana tabacum), and designated as NtROS1, NtROS2a, NtROS2b and NtROS3, each respectively encoding a polypeptide with 1796, 1673, 1673 and 1662 amino acids. Purified NtROS1 and NtROS2a proteins expressed in Sf9 insect cells clearly exhibited activity of m 5 C removal from tobacco genomic DNA in vitro. GFP fusion assay showed that NtROS1 and NtROS2a were localized in nucleus. Transcripts of NtROS1, NtROS2a and NtROS3 were induced by abiotic stresses, including aluminium, salt and reactive oxygen species. These observations suggested that NtROS proteins function in demethylating process of genomic DNA during plant stress response, thereby maintaining the balance of gene expression in combination with DNA methyltransferases.