Polygala tenuifolia extract inhibits lipid accumulation in 3T3-L1 adipocytes and high-fat diet-induced obese mouse model and affects hepatic transcriptome and gut microbiota profiles

Obesity, the excessive accumulation of lipids in the body, is closely associated with many prevalent human disorders. Continued efforts to identify plant extracts that exhibit anti-obesity effects have drawn much attention. This study investigated whether a Polygala tenuifolia extract (PTE) possesses anti-obesity activity and how PTE may affect liver gene expression and gut microbiota. We used 3T3-L1 adipocytes and a high-fat diet–induced obese mouse model to determine the effects of PTE on lipid accumulation. Next-generation sequencing analysis of liver gene expression and gut microbiota profiles following PTE treatment were conducted to elucidate possible mechanisms. We found that treatment of fully differentiated 3T3-L1 adipocytes with PTE inhibited lipid accumulation in the cells through reducing lipid formation and triglyceride content and by increasing lipase activity. No cytotoxicity was observed from the PTE treatment. After 5 weeks of treatment with PTE, the increased body weight, elevated serum triglyceride content, and liver steatosis in the high-fat diet–induced obese mice were each reduced. Liver transcriptomic analysis revealed that expression of genes involved in lipid and cholesterol metabolism was significantly altered. The low-grade chronic inflammation of obesity caused by a high-fat diet was also decreased after PTE treatment. In addition, treatment with PTE improved the relatively low Bacteroidetes/Firmicutes ratio in the gut of high-fat diet–fed mice through enrichment of the Proteobacteria population and reduction of the Deferribacteres population. In conclusion, treatment with PTE inhibited lipid accumulation by inducing the expression of the master transcription factor PPARα, attenuated the low-grade chronic inflammation of obesity, and also altered gut microbiota profiles. These results indicate that PTE has the potential to be developed into an anti-obesity food supplement and therapy.

Abbreviations: Abcg5: ATP-binding cassette subfamily G member 5; ALT: alanine aminotransferase; AMPK: adenosine monophosphate-activated protein kinase; AST: aspartate aminotransferase; B/F: Bacteroidetes to Firmicutes [ratio]; C/EBPα: CCAAT/enhancer-binding protein alpha; CR: creatinine; Cyp51: cytochrome P450 family 51; DMEM: Dulbecco’s modified Eagle’s medium; Fabp5: fatty acid-binding protein 5; FBS: fetal bovine serum; Fdps: farnesyl diphosphate synthase; Glc: Glucose; HFD: high-fat diet; GO: gene ontology; HPRT: hypoxanthine guanine phosphoribosyl transferase; IBMS: 3-isobutyl-1-methylxanthine; Idi1: isopentenyl-diphosphate delta isomerase 1; IL-1β: interleukin-1-beta; Lpin1: phosphatidic acid phosphohydrolase; LPS: lipopolysaccharide; Mvd: mevalonate diphosphate decarboxylase; ND: normal diet; OTU: operational taxonomic units; Pcsk9: proprotein convertase subtilisin/kexin 9; Pctp: phosphatidylcholine transfer protein; PPARα: peroxisome proliferator-activated receptor alpha; PPARγ: peroxisome proliferator-activated receptor gamma; PTE: Polygala tenuifolia extract; Saa1: serum amyloid A1; SD: standard deviation; SEM: standard error of the mean; Serpina12: serpin family member 12; Sqle: squalene monooxygenase; SREBP1C: sterol regulatory element-binding protein 1C; TCHO: total cholesterol; TG: triglyceride

Antioxidant and anti-inflammatory activities of Lonicera japonica Thunb. var. sempervillosa Hayata flower bud extracts prepared by water, ethanol and supercritical fluid extraction techniques

Lonicera japonica Thunberg (LJ) has long been used as an antipyretic, anti-inflammatory and anti-infectious agent in East Asia. The subspecies L. japonica Thunb. var. sempervillosa Hayata (LJv) is a variant that mainly grows in Taiwan. This study examined the antioxidant and anti-inflammatory activities of the extracts from the flower buds of these two species. The extracts were obtained by three extraction methods: water extraction, ethanol extraction, and supercritical-CO2 fluid extraction (SFE). The antioxidant activities of dry LJ (dLJ) extracts were superior to those of LJv extracts. Water extracts possessed higher activities than that prepared by ethanol or SFE. The total polyphenols content, total flavonoids content, and the amount of chlorogenic acid and luteolin-7-O-glucoside were all higher in the water extracts compared to the other two. The SFE extracts of these two species all exhibited excellent anti-inflammatory activities. Although the water and ethanol extracts of dLJ extracts had higher anti-inflammatory activity than that of LJv extracts, the SFE extracts prepared from fresh LJv flower buds (fLJv) exhibited the highest activity among all extracts. The SFE effectively isolates the bioactive components of L. japonica and can obtain the L. japonica extracts with high anti-inflammatory activity.

Identification of species and materia medica within Angelica L. (Umbelliferae) based on phylogeny inferred from DNA barcodes

DNA barcodes have been increasingly used in authentication of medicinal plants, while their wide application in materia medica is limited in their accuracy due to incomplete sampling of species and absence of identification for materia medica. In this study, 95 leaf accessions of 23 species (including one variety) and materia medica of three Pharmacopoeia-recorded species of Angelica in China were collected to evaluate the effectiveness of four DNA barcodes (rbcL, matK, trnH-psbA and ITS). Our results showed that ITS provided the best discriminatory power by resolving 17 species as monophyletic lineages without shared alleles and exhibited the largest barcoding gap among the four single barcodes. The phylogenetic analysis of ITS showed that Levisticum officinale and Angelica sinensis were sister taxa, which indicates that L. officinale should be considered as a species of Angelica. The combination of ITS + rbcL + matK + trnH-psbA performed slight better discriminatory power than ITS, recovering 23 species without shared alleles and 19 species as monophyletic clades in ML tree. Authentication of materia medica using ITS revealed that the decoction pieces of A. sinensis and A. biserrata were partially adulterated with those of L. officinale, and the temperature around 80 °C processing A. dahurica decoction pieces obviously reduced the efficiency of PCR and sequencing. The examination of two cultivated varieties of A. dahurica from different localities indicated that the four DNA barcodes are inefficient for discriminating geographical authenticity of conspecific materia medica. This study provides an empirical paradigm in identification of medicinal plants and their materia medica using DNA barcodes.

Typhonium blumei extract inhibits proliferation of human lung adenocarcinoma A549 cells via induction of cell cycle arrest and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Typhonium blumei Nicolson & Sivadasan is a traditional Chinese medicinal herb endowing with detumescence, detoxification, anti-inflammation activities, and has been used as a folk prescription on anticancer in Taiwan.

AIM OF THE STUDY

The purpose of this study is to investigate the inhibitory effect of Typhonium blumei (Tb) extract on the viability of different cancer cells and the apoptotic effect of this extract on A549 lung cancer cells.

MATERIALS AND METHODS

Human A549 cell line and other cancer cell lines were treated with different concentrations of Tb extract at different time intervals. Growth inhibition was determined by MTT assay. Apoptosis was detected by cell morphologic observation, cell cycle analysis, and immunoblot analysis on the expression of protein associated with cell death. GC-MS were used to determine the chemical constituents of this extract.

RESULTS

The Tb extract had cytotoxicity toward A549 lung cancer cells (IC(50)=97.7 μg/ml), LNCaP prostate cancer cells (IC(50)=124.5 μg/ml) and MCF-7 breast cancer cells (IC(50)=125.8 μg/ml). Conversely, the adverse effects of Tb extract on normal embryonic lung fibroblast MRC-5 cells (IC(50)=245.5 μg/ml) and embryonic kidney fibroblast HEK293 cells (IC(50)=251.1 μg/ml) were comparatively low. Cytometric analysis results demonstrate that A549 cells were arrested at the G2/M phase by treatment with Tb extract. The extract induced A549 cell apoptosis via the mitochondrial pathway by down-regulating Bcl-2 and Bcl-xL protein expression, up-regulating Bax, Bad and Bak protein expression, and activating caspase-9 and caspase-3. Experimental results of bioactive compound analysis indicate that dibutyl phthalate, α-linolenic acid, phytol, campesterol, stigmasterol and β-sitosterol were the major bioactive ingredients of Tb extract. Although all these compounds had good anti-proliferative effects on A549 cells, campesterol (IC(50)=2.2 μM for 24h treatment) and β-sitosterol (IC(50)=1.9 μM for 24h treatment) displayed the greatest inhibitory activity.

CONCLUSIONS

Experimental results of this study suggest that the Tb extract exerts potential anticancer activity through the growth inhibition and the apoptosis on A549 cells.

Functional characterization of three ethylene response factor genes from Bupleurum kaoi indicates that BkERFs mediate resistance to Botrytis cinerea

Three novel ethylene response factor (ERF) genes, BkERF1, BkERF2.1 and BkERF2.2, were isolated from a medicinal plant, Bupleurum kaoi. The deduced BkERFs contain a canonical nuclear localization signal and an ERF/AP2 DNA binding domain. RNA gel blot analysis revealed that BkERF1 and BkERF2.1 were ubiquitously expressed at low levels in all parts of mature plants, and that BkERF2.2 was expressed at moderate levels in vegetative tissues. Exogenous application of methyl jasmonate induced BkERF1/2.1/2.2 transcripts. BkERF2.2 transcript levels were slightly increased by addition of ethephon and salicylic acid. BkERFs were localized in the plant nucleus and functioned as transcriptional activators. In B. kaoi cells overexpressing BKERFs, inoculation with Botrytis cinerea increased expression of some defense genes which are associated with enhanced disease resistance. Similarly, overexpression of BkERFs in transgenic Arabidopsis thaliana resulted in elevated mRNA levels of the defense gene PDF1.2, and in enhanced resistance to B. cinerea. Collectively, these results provide evidence that BkERFs mediate the expression of defense-related genes in plants.

Development and validation of molecular markers for characterization of Boehmeria nivea var. nivea and Boehmeria nivea var. tenacissima

BACKGROUND

The root of Boehmeria spp (ramie) is a hepatoprotective Chinese herbal medicine. Medicinal properties vary between Boehmeria nivea var. nivea and Boehmeria nivea var. tenacissima, which are local species found in Taiwan. As commercial preparations may use either species, there is a need for a rapid and simple assay to identify variants for quality control.

METHODS

Four methods were developed and tested for their applicability in differentiating the two species. These methods were random amplified polymorphic DNA (RAPD); sequence characterized amplified regions (SCAR); single nucleotide polymorphisms (SNP) and cleaved amplified polymorphic sequences (CAPS).

RESULTS

Three RAPD markers were developed that produced unique bands in B. nivea var. tenacissima and B. nivea var. nivea. Based on sequenced RAPD bands, one SCAR marker was developed that produced a single DNA band in B. nivea var. nivea. Two SNP markers differentiated between B. nivea var. nivea and B. nivea var. tenacissima based on single nucleotide substitutions. A pair of CAPS oligonucleotides was developed by amplifying a 0.55-kb DNA fragment that exhibited species-specific digestion patterns with restriction enzymes Alf III and Nde I. Consistent results were obtained with all the four markers on all tested Boehmeria lines.

CONCLUSION

The present study demonstrates the use of the RAPD, SCAR, SNP and CAPS markers for rapid identification of two closely related Boehmeria species.

Characterization of the Scutellaria barbata glycosyltransferase gene and its promoter

The conversion of flavonoid aglycones to their glycosides by plant glycosyltransferases may affect a wide range of outcomes, including stability, solubility and bioavailability. Scutellaria barbata, rich in flavonoid glycosides, is widely used as a traditional Chinese herbal medicine. In this study, a flavonoid glycosyltransferase cDNA (SbUGT) and its promoter from S. barbata were cloned and characterized as a flavonoid glycosyltransferase using whole-cell biotransformation. Fragments of different lengths of the 5'-flanking region of the SbUGT gene were fused to the beta-glucuronidase (GUS) gene and analyzed with transgenic Arabidopsis plants using histochemical and fluorometric assays. GUS activity in transgenic plants carrying the SbP-850U construct (-850 to +86 relative to the transcription start site) displayed the highest level and was enhanced by salt and methyl jasmonate, similar to the expression patterns of the endogenous SbUGT. GUS activity disappeared when the promoter was deleted to -98, and deletion analyses indicated the existence of positive and negative regulatory element(s). Unexpectedly, plants carrying the construct SbP-102U (-102 to +86) exhibited strong GUS activity exclusively in the roots. Our experiments revealed that the specific expression is mediated by different promoter regions and the unique region driving root-preferred expression can be used as a root-specific promoter.

Abstract LB-160: ITRI-260, a promising candidate for treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly malignant hematopoietic tumor characterized by an abnormal proliferation of myeloid progenitor cells, decreased rate of self-destruction and an arrest in cell differentiation. The internal tandem duplication mutations of FMS-like tyrosine kinase-3 (FLT3/ITD mutations) are common in AML and linked to poor prognosis. ITRI-260 generated from designed by computer-assisted rationale drug design and in silico prioritized approaches, was proved to be a potent cell growth inhibitor against FLT3/ITD mutated AML cells through FLT3 and c-Kit inhibition. The in vivo efficacy of ITRI-260 via oral route was demonstrated in MV4-11 xenograft mice model. Besides, two more orthotopic murine models were used to assess the in vivo therapeutic efficacy of ITRI-260. The first one is MV4-11 cell orthotopically engraft into NOD/SCID mice bone marrow and the second one is primary AML cells from AML patient engraft into NOD/SCID mice bone marrow. The results show that ITII-260 can decrease FLT3/ITD mutant leukemia blasts in peripheral blood and bone marrow in both animal models. Finally, ITRI-260 prolongs the survival in both bone marrow engraft mice models. These findings strongly suggest clinical benefits of ITRI-260 in patients with FLT3/ITD AML. Currently we are planning the bridged projects to push ITRI-260 toward IND status.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-160.

Sennoside B inhibits PDGF receptor signaling and cell proliferation induced by PDGF-BB in human osteosarcoma cells

AIMS

To address the possibility that sennoside B inhibition of cell proliferation is mediated via interference with platelet-derived growth factor (PDGF) signaling.

MAIN METHODS

Human osteosarcoma MG63 cells were treated with PDGF in the presence or absence of sennoside B. Activation of the PDGF signaling pathway was monitored using western immunoblotting with specific antibodies against the PDGF receptor, phosphotyrosine and components of the downstream signaling cascade. Activation of cell metabolism and proliferation was assessed by chromogenic reduction of MTT.

KEY FINDINGS

Sennoside B was found to inhibit PDGF-BB-induced phosphorylation of the PDGF receptor (PDGFR) in human MG63 osteosarcoma cells. Downstream signaling was also affected; pre-incubation of PDGF-BB with sennoside B inhibited the phosphorylation of pathway components including Ak strain transforming protein (AKT), signal transducer and activator of transcription 5 (STAT-5) and extracellular signal-regulated kinase 1/2 (ERK1/2). Further, we found that sennoside B can bind directly to the extracellular domains of both PDGF-BB and the PDGF-beta receptor (PDGFR-beta). The effect was specific for sennoside B; other similar compounds including aloe-emodin, rhein and the meso isomer (sennoside A) failed to inhibit PDGFR activation or downstream signaling. Sennoside B also inhibited PDGF-BB stimulation of MG63 cell proliferation.

SIGNIFICANCE

These results indicate that sennoside B can inhibit PDGF-stimulated cell proliferation by binding to PDGF-BB and its receptor and by down-regulating the PDGFR-beta signaling pathway. Sennoside B is therefore of potential utility in the treatment of proliferative diseases in which PDGF signaling plays a central role.

Authentication of medicinal herbs using PCR-amplified ITS2 with specific primers

Different parts of medicinal herbs have long been used as traditional Chinese drugs for treating many diseases, whereas materials of similar morphology and chemical fingerprints are often misidentified. Analyses of sequence variations in the nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) have become a valid method for authentication of medicinal herbs at the intergenic and interspecific levels. DNA extracted from processed materials is usually severely degraded or contaminated by microorganisms, thus generates no or unexpected PCR products. The goal of this study is to apply the ITS fragments selectively amplified with two designed primer sets for efficient and precise authentication of medicinal herbs. The designed primers led to an accurate PCR product of the specific region in ITS2, which was confirmed with DNA extracted from 55 processed medicinal herbs belonging to 48 families. Moreover, the selectively amplified ITS2 authenticated five sets of easily confusable Chinese herbal materials. The designed primers were proven to be suitable for a broad application in the authentication of herbal materials.

Synthetic models for the zinc sites in the methionine synthases

The syntheses and molecular structures of a series of tetrahedral zinc complexes designed to model the active sites in Escherichia coli methionine synthases are reported. [PhTttBu]ZnBr (PhTttBu = phenyltris((tert-butylthio)-methyl)borate) was prepared and characterized crystallographically to provide entry into [S3]ZnX complexes. Metathesis with KSPh yielded the phenylthiolato complex, [PhTttBu]Zn(SPh), which represents a structural mimic of the homocysteine ligated form of the enzyme. Alternatively, [S2N]ZnX (X = Br, CH3, SPh) species were prepared using the new mixed-donor ligands, [Ph(pz)BttBu] (phenyl(pyrazolyl)bis((tert-butylthio)methyl)borate) and [Ph(pztBu)BttBu] (phenyl(3-tert-butylpyrazolyl)bis((tert- butylthio)methyl)borate). Protonolysis of [Ph(pztBu)-BttBu]Zn(CH3) by PhSH in toluene yielded [Ph(pztBu)BttBu]Zn(SPh), a synthetic analogue of the homocysteine ligated form of cobalamin-independent methionine synthase (Met E). The average Zn-S bond distance in [Ph-(pztBu)BttBu]Zn(SPh) of 2.37 A compares well with the EXAFS-derived distance of 2.31 A found in the homocysteine-bound form of Met E.

Cloning of the cDNA encoding Scg-SPRP, an unusual Ser-protease-related protein from vitellogenic female desert locusts (Schistocerca gregaria)

The cDNA coding for a Ser-protease-related protein (Scg-SPRP) was cloned from desert locust (Schistocerca gregaria) midgut. The derived amino acid sequence consists of 260 residues and shows strong sequence similarity to insect trypsin-like molecules. It is, however, likely that Scg-SPRP is not a proteolytically active enzyme and that it plays another physiologically relevant role, since two out of three residues which are indispensable for catalytic activity of Ser-proteases are replaced. Northern analysis revealed that the Scg-SPRP gene is expressed in midgut tissue and that this expression is strongly induced in adult female locusts. Moreover, the occurrence of the transcript (1.2 kb) fluctuates during the molting cycle and during the female reproductive cycle. Juvenile hormone (JH III) dependence of transcription was investigated by chemical allatectomy (precocene I) of adult females. This resulted in inhibition of vitellogenesis and in disappearance of the Scg-SPRP transcript. Expression of Scg-SPRP in precocene-treated locusts could be reinduced by additional treatment with JH III or with 20-OH-ecdysone.

Purification of toxic compounds from larvae of the gray fleshfly: the identification of paralysins

Larval haemolymph of Neobellieria bullata (Insecta, Diptera) is highly toxic to adults of the same species: injection causes instant paralysis to death. Referring to their dramatic effect in adult insects the responsible compounds were designated paralysins. Two paralysins, soluble in organic solvents and heat stable, were chromatographically purified to homogeneity. They were identified by use of mass spectrometry and nuclear magnetic resonance respectively as beta-alanine-tyrosine (beta-Ala-Tyr) and as 3-hydroxy-kynurenine (3-HK). The quantities of beta-Ala-Tyr and 3-HK in the insect appear to increase steadily during larval development, with peak values prior to the pupal stage. These findings may contribute to a better understanding of some aspects of the process of insect metamorphosis. Orienting experiments in mammals suggest that both compounds, when injected intraspinally, are also neurotoxic to rats. In addition, cytotoxicity tests revealed that 3-HK, but not beta-Ala-Tyr is toxic to human neuroblastoma cells, rat primary cortex neurons as well as to rat glial cells.

Cloning of two cDNAs encoding three small serine protease inhibiting peptides from the desert locust Schistocerca gregaria and analysis of tissue-dependent and stage-dependent expression

This study describes the cloning of two cDNAs encoding three serine-protease-inhibiting peptides, SGPI I, II and III, which were recently identified from ovarian extracts of the desert locust, Schistocerca gregaria. The first cDNA codes for the precursor polypeptides of SGPI I and SGPI II; the second encodes only a single inhibitor, SGPI III. Northern-blot analysis revealed an approximate length of 0.8 kb for SGPI-I/II mRNA and 0.6 kb for SGPI-III mRNA. The transcripts are present in several locust tissues, but they could not be detected in the midgut. The gene for SGPI-I/II is abundantly transcribed during all larval and adult stages, whereas SGPI-III mRNA is mainly present in adults. Northern-blot hybridization also revealed important changes in the SGPI-mRNA content during the molting cycle and during the adult reproductive cycle. Moreover, a differential hormonal control was observed in adult females which had been treated with precocene, juvenile hormone or ecdysone.

Purification and characterization of a group of five novel peptide serine protease inhibitors from ovaries of the desert locust, Schistocerca gregaria

The ovary of the desert locust, Schistocerca gregaria, contains multiple inhibitors of serine proteases. Five serine protease inhibitors, designated SGPI-1-5 (Schistocerca gregaria protease inhibitors) were purified from methanolic extracts of mature ovaries and analyzed by mass spectrometry and amino acid sequencing. The revealed primary structures display amino acid similarities and are related to the serine protease inhibitors identified in the hemolymph of Locusta migratoria. All inhibitors show an in vitro inhibiting activity towards alpha-chymotrypsin. In addition, SGPI-1 displays in vitro inhibiting activity towards trypsin, and SGPI-2 is a potent pancreatic elastase inhibitor. Differences in inhibitory specificities towards the locust endogenous serine proteases can be readily attributed to the amino acid sequence within the active region and also to amino acid residues beyond the P1-P'1 bond. A difference in one or two amino acid residues around the reactive sites results in considerable alteration of the inhibitory specificity. The temporal and spatial distribution of SGPI-1-5 was studied by RP-HPLC analysis. All inhibitors occur in hemolymph, ovaries, testes and fat body of adults but are absent in the gut. They are also present in larval hemolymph and fat body. An antibody raised against SGPI-2 shows positive immunostaining in the ovarian follicle cells.

Cloning and characterization of a gene required for the secretion of extracellular enzymes across the outer membrane by Xanthomonas campestris pv. campestris

Nonpathogenic mutants of Xanthomonas campestris pv. campestris, generated from transposon mutagenesis, accumulated extracellular polygalacturonate lyase, alpha-amylase, and endoglucanase in the periplasm. The transposon Tn5 was introduced by a mobilizable, suicidal plasmid, pSUP2021 or pEYDG1. Genomic banks of wild-type X. campestris pv. campestris, constructed on the broad-host-range, mobilizable cosmid pLAFR1 or pLAFR3, were conjugated with one of the mutants, designated XC1708. Recombinant plasmids isolated by their ability to complement XC1708 can be classified into two categories. One, represented by pLASC3, can complement some mutants, whereas the other, represented by a single plasmid, pLAHH2, can complement all of the other mutants. Restriction mapping showed that the two recombinant plasmids shared an EcoRI fragment of 8.9 kb. Results from subcloning, deletion mapping, and mini-Mu insertional mutation of the 8.9-kb EcoRI fragment suggested that a 4.2-kb fragment was sufficient to complement the mutant XC1708. Sequence analysis of this 4.2-kb fragment revealed three consecutive open reading frames (ORFs), ORF1, ORF2, and ORF3. Hybridization experiments showed that Tn5 in the genome of XC1708 and other mutants complemented by pLASC3 was located in ORF3, which could code for a protein of 83.5 kDa. A signal peptidase II processing site was identified at the N terminus of the predicted amino acid sequence. Sequence homology of 51% was observed between the amino acid sequences predicted from ORF3 and the pulD gene of Klebsiella species.

The melanin operon of Streptomyces antibioticus: expression and use as a marker in gram-negative bacteria

The melC operon of Streptomyces antibioticus contains two genes, melC1 and melC2, necessary for the production of melanin pigment. We transferred the coding sequence of melC1 and melC2 to Escherichia coli plasmid pMTL23 such that its transcription was under the control of the lac promoter and melC1 was translationally fused to the lacZ alpha fragment. E. coli cultures containing this plasmid, pIF413, produced melanin after overnight incubation on 2YT agar supplemented with 0.1 mM CuCl2, 0.36 mM IPTG (or 0.2% lactose), and 2 mM tyrosine. Erwina carotovora could also be transformed by pIF413 to produce melanin. Two shuttle vectors were constructed: pLUS415 for E. coli and Streptomyces, and pLAF413 for E. coli and Xanthomonas campestris. These vectors confer melanin pigmentation in all the hosts that harbor them. The melC sequence provides the vectors with a convenient cloning marker for insertional or replacement inactivation.

Rhinocerebral mucormycosis

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