[Learning from Natural Products: Study on Actinomycetes of the Genus Nocardia]

The genus Nocardia comprises gram-positive bacteria, most of which are pathogenic and cause opportunistic infections of the lungs, skin, and brain in humans. Based on a collaboration study with the Medical Mycology Research Center, Chiba University, we focused on Nocardia actinomycetes as a new natural-product resource. First, by culturing (monoculture) Nocardia in various media, we isolated a new aminocyclitol nabscessin A from Nocardia abscessus IFM10029T and a new γ-lactone inohanalactone from Nocardia inohanaensis IFM0092T. On the other hand, by imitating the state in which the genus Nocardia actinomycete infects animal cells and culturing the genus in the presence of animal cells (coculture), this genus was expected to produce new compounds through interactions with the animal cells. Using mouse macrophage-like cells (J774.1) as animal cells, a new pantothenic acid amide derivative and a cyclic peptide, nocarjamide, with Wnt signal activation activity were isolated from Nocardia tenerifensis IFM10554T strain.

Identification of Nocardia and non-tuberculous Mycobacterium species by MALDI-TOF MS using the VITEK MS coupled to IVD and RUO databases

Identification of Nocardia and Mycobacterium species by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is still a challenging task that requires both suitable protein extraction procedures and extensive databases. This study aimed to evaluate the VITEK MS Plus system coupled with updated RUO (v4.17) and IVD (v3.2) databases for the identification of Nocardia spp. and Mycobacterium spp. clinical isolates. Sample preparation was carried out using the VITEK MS Mycobacterium/Nocardia kit for protein extraction. From 90 Nocardia spp. isolates analysed, 86 (95.6%) were correctly identified at species or complex level using IVD and 78 (86.7%) using RUO. Only two strains were misidentified as other species pertaining to the same complex. Among the 106 non-tuberculous Mycobacterium clinical isolates tested from a liquid culture medium, VITEK MS identified correctly at species or complex level 96 (90.6%) isolates in the IVD mode and 89 (84.0%) isolates in the RUO mode. No misidentifications were detected. Although the IVD mode was unable to differentiate members of the M. fortuitum complex, the RUO mode correctly discriminated M. peregrinum and M. septicum. The robustness and accuracy showed by this system allow its implementation for routine identification of these microorganisms in clinical laboratories.

Nocathioamides, Uncovered by a Tunable Metabologenomic Approach, Define a Novel Class of Chimeric Lanthipeptides

The increasing number of available genomes, in combination with advanced genome mining techniques, unveiled a plethora of biosynthetic gene clusters (BGCs) coding for ribosomally synthesized and post-translationally modified peptides (RiPPs). The products of these BGCs often represent an enormous resource for new and bioactive compounds, but frequently, they cannot be readily isolated and remain cryptic. Here, we describe a tunable metabologenomic approach that recruits a synergism of bioinformatics in tandem with isotope- and NMR-guided platform to identify the product of an orphan RiPP gene cluster in the genomes of Nocardia terpenica IFM 0406 and 0706T . The application of this tactic resulted in the discovery of nocathioamides family as a founder of a new class of chimeric lanthipeptides I.

Microketides A and B, Polyketides from a Gorgonian-Derived Microsphaeropsis sp. Fungus

Microketides A and B (1 and 2), a pair of new C-11 epimeric polyketides, were obtained from the gorgonian-derived fungus Microsphaeropsis sp. RA10-14 collected from the South China Sea. The absolute configurations of 1 and 2 were assigned by the modified Mosher's method, TDDFT-ECD, and NMR calculations. Compounds 1 and 2 were evaluated for antibacterial, antifungal, and growth inhibition of marine phytoplankton activities. Microketide A (1) exhibited promising inhibitory activity against Pseudomonas aeruginosa, Nocardia brasiliensis, Kocuria rhizophila, and Bacillus anthraci with the same MIC value as ciprofloxacin (0.19 μg/mL).

Protective Effects of Nargenicin A1 against Tacrolimus-Induced Oxidative Stress in Hirame Natural Embryo Cells

Tacrolimus is widely used as an immunosuppressant to reduce the risk of rejection after organ transplantation, but its cytotoxicity is problematic. Nargenicin A1 is an antibiotic extracted from Nocardia argentinensis and is known to have antioxidant activity, though its mode of action is unknown. The present study was undertaken to evaluate the protective effects of nargenicin A1 on DNA damage and apoptosis induced by tacrolimus in hirame natural embryo (HINAE) cells. We found that reduced HINAE cell survival by tacrolimus was due to the induction of DNA damage and apoptosis, both of which were prevented by co-treating nargenicin A1 or N-acetyl-l-cysteine, a reactive oxygen species (ROS) scavenger, with tacrolimus. In addition, apoptosis induction by tacrolimus was accompanied by increases in ROS generation and decreases in adenosine triphosphate (ATP) levels caused by mitochondrial dysfunction, and these changes were significantly attenuated in the presence of nargenicin A1, which further indicated tacrolimus-induced apoptosis involved an oxidative stress-associated mechanism. Furthermore, nargenicin A1 suppressed tacrolimus-induced B-cell lymphoma-2 (Bcl-2) down-regulation, Bax up-regulation, and caspase-3 activation. Collectively, these results demonstrate that nargenicin A1 protects HINAE cells against tacrolimus-induced DNA damage and apoptosis, at least in part, by scavenging ROS and thus suppressing the mitochondrial-dependent apoptotic pathway.

Production of a Novel Tetrahydroxynaphthalene (THN) Derivative from Nocardia sp. CS682 by Metabolic Engineering and Its Bioactivities

Nargenicin A1 is major secondary metabolite produced by Nocardia sp. CS682, with an effective antibacterial activity against various Gram-positive bacteria. Most Nocardia spp. have metabolic ability to produce compounds of diverse nature, so one-strain-many-compounds (OSMAC) approach can be applied for obtaining versatile compounds from these strains. In this study, we characterized a novel 1, 3, 6, 8-tetrahydroxynaphthalene (THN) derivative by metabolic engineering approach leading to the inactivation of nargenicin A1 biosynthesis. By using genome mining, metabolite profiling, and bioinformatics, the biosynthetic gene cluster and biosynthetic mechanism were elucidated. Further, the antibacterial, anticancer, melanin formation, and UV protective properties for isolated THN compound were performed. The compound did not exhibit significant antibacterial and cytotoxic activities, but it exhibited promising UV protection effects. Thus, metabolic engineering is an effective strategy for discovering novel bioactive molecules.

Controlling Interactions of Cyclic Oligosaccharides with Hetero-Oligomeric Nanopores: Kinetics of Binding and Release at the Single-Molecule Level

Controlling the molecular interactions through protein nanopores is crucial for effectively detecting single molecules. Here, the development of a hetero-oligomeric nanopore derived from Nocardia farcinica porin AB (NfpAB) is discussed for single-molecule sensing of biopolymers. Using single-channel recording, the interaction of cyclic oligosaccharides such as cationic cyclodextrins (CDs) of different symmetries and charges with NfpAB is measured. Studies of the transport kinetics of CDs reveal asymmetric geometry and charge distribution of NfpAB. The applied potential promotes the attachment of the cationic CDs to the negatively charged pore surface due to electrostatic interaction. Further, the attached CDs are released from the pore by reversing the applied potential in time-resolved blockages. Release of CDs from the pore depends on its charge, size, and magnitude of the applied potential. The kinetics of CD attachment and release is controlled by fine-tuning the applied potential demonstrating the successful molecular transport across these nanopores. It is suggested that such controlled molecular interactions with protein nanopores using organic templates can be useful for several applications in nanopore technology and single-molecule chemistry.

Nocardia zhihengii sp. nov., an actinobacterium isolated from rhizosphere soil of Psammosilene tunicoides

A Nocardia-like actinobacterial strain, designated YIM TG2190^T, was isolated from rhizosphere soil of Psammosilene tunicoides collected from Gejiu, Yunnan province, China. The cells of strain YIM TG2190^T were observed to be Gram-stain positive and non-motile. The strain forms extensively branched substrate mycelia that fragments into rod-shaped elements. The 16S rRNA gene sequence analysis showed that strain YIM TG2190^T is closely related to Nocardia nova (97.5%), Nocardia jiangxiensis (97.1%) and Nocardia miyunensis (96.8%). Growth occurs at 4-30 °C (optimum 28 °C), pH 6.0-8.0 (optimum pH 7.0) and the strain can tolerate NaCl (w/v) up to 3% (optimum 0-1%). The cell walls were found to contain meso-diaminopimelic acid. The whole-cell sugars were identified as glucose, mannose, ribose, galactose, arabinose and fucose. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylglycerol and an unidentified phospholipid. The menaquinones detected were MK-9 (H₂) and MK-8 (H₄). The major fatty acids (> 5%) were found to be C_16:0 (33.9%), summed feature 3 (21.7%), C_18:0 10-methyl TBSA (13.7%) and C_18:1ω9c (7.0%). The DNA G+C content was determined to be 61.1 mol%. DNA-DNA relatedness between the strain YIM TG2190^T and N. nova CGMCC 4.1705^T, N. jiangxiensis CGMCC 4.1905^T and N. miyunensis CGMCC 4.1904^T were 46.9 ± 2.6, 36.8 ± 1.3, and 35.7 ± 2.6%, respectively, values which are less than the threshold value (70%) for the delineation of prokaryotic genomic species. The phenotypic, chemotaxonomic and phylogenetic data indicates that strain YIM TG2190^T represents a novel species of the genus Nocardia, for which the name Nocardia zhihengii sp. nov. is proposed. The type strain is YIM TG2190^T (=KCTC 39596^T = DSM 100515^T).

Role of FNA and Special Stains in Rapid Cytopathological Diagnosis of Pulmonary Nocardiosis

BACKGROUND

Nocardia, a gram-positive aerobic bacillus of the Actinomycetales family, is a significant opportunistic pathogen in immunocompromised individuals. Clinical and radiological features of pulmonary nocardiosis are nonspecific and can be misdiagnosed as tuberculosis, pneumocystis, staphylococcal or fungal infections, or as malignancy. Aspiration cytology with special stains is a quick and effective approach for accurate diagnosis.

MATERIALS AND METHODS

We present 7 cases of pulmonary nocardiosis, admitted to the pathology department in a tertiary-care hospital in Punjab. Clinical findings, immune status, laboratory tests, chest radiographs, and computed tomography scans were reviewed. Cytologically, special stains like 1% Ziehl-Neelsen (ZN), 20% ZN, periodic acid-Schiff (PAS), Grocott methenamine silver (GMS), and reticulin stains were studied along with May-Grünwald Giemsa, Papanicolaou, and hematoxylin and eosin.

RESULTS

All the patients were immunocompromised. The radiological changes were nonspecific. Cytomorphology showed acute and chronic inflammatory infiltrates with necrosis. None of the cases showed well-defined granulomas. GMS, modified 1% ZN and, Gordon and Sweet reticulin stains highlighted the delicate filamentous bacteria in all cases. PAS and 20% ZN stain for tuberculous bacilli were uniformly negative.

CONCLUSION

FNAC can provide a quick and accurate diagnosis of nocardiosis and thereby facilitate timely medical management.

A new α-pyrone from the deep-sea actinomycete Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111(T)

A new α-pyrone, nocapyrone S (1), together with five known compounds (2-6), were isolated from the deep-sea actinomycete Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111(T). Their structures were determined by spectroscopic analyses. The absolute configuration of 1 was established by quantum approaches. Cytotoxic activity of 1 was evaluated against K562, MCF-7, SGC7901, A375, Hela, and HepG2 cell lines.

Nabscessins A and B, Aminocyclitol Derivatives from Nocardia abscessus IFM 10029T

Two new aminocyclitol amide derivatives, nabscessins A (1) and B (2), were isolated from the culture broth of a pathogenic actinomycete species, Nocardia abscessus IFM 10029^T. The structures of nabscessins A and B were elucidated by spectral studies, and the compounds showed antifungal activity against Cryptococcus neoformans, with IC₅₀ values of 32 and 16 μg/mL, respectively.

Antagonistic Activity of Nocardia brasiliensis PTCC 1422 Against Isolated Enterobacteriaceae from Urinary Tract Infections

The main drawback of current antibiotic therapies is the emergence and rapid increase in antibiotic resistance. Nocardiae are aerobic, Gram-positive, catalase-positive, non-motile actinomycetes. Nocardia brasiliensis was reported as antibiotic producer. The purpose of the study was to determine antibacterial activity of N. brasiliensis PTCC 1422 against isolated Enterobacteriaceae from urinary tract infections (UTIs). The common bacteria from UTIs were isolated from hospital samples. Antimicrobial susceptibility test was performed for the isolated pathogens using Kirby-Bauer disk diffusion method according to clinical and Laboratory Standards Institute guideline. Antagonistic activity of N. brasiliensis PTCC 1422 was examined with well diffusion methods. Supernatant of N. brasiliensis PTCC 1422 by submerged culture was analyzed with gas chromatography-mass spectrometry. Isolated strains included Escherichia coli, Klebsiella pneumoniae, Serratia marcescens and Proteus mirabilis. The most common pathogen isolated was E. coli (72.5%). Bacterial isolates revealed the presence of high levels of antimicrobial resistances to ceftriaxone and low levels of resistance to cephalexin. Supernatant of N. brasiliensis PTCC 1422 showed antibacterial activity against all of the isolated microorganisms in well diffusion method. The antibiotic resistance among the uropathogens is an evolving process, so a routine surveillance to monitor the etiologic agents of UTI and the resistance pattern should be carried out timely to choose the most effective empirical treatment by the physicians. Our present investigation indicates that the substances present in the N. brasiliensis PTCC 1422 could be used to inhibit the growth of human pathogen. Antibacterial resistance among bacterial uropathogen is an evolving process. Therefore, in the field on the need of re-evaluation of empirical treatment of UTIs, our present. The study has demonstrated that N. brasiliensis PTCC 1422 has a high potential for the treatment of UTIs.

[Biological Properties of Nocardia vaccinii IMV B-7405 Surfactants Synthesized on Byproduct of Biodiesel Production]

AIM

Comparison of antimicrobial and anti-adhesive activity of Nocardia vaccinii ІMV B-7405 surfactants synthesized on purified and technical glycerol (byproduct of biodiesel production).

METHODS

Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). Antimicrobial against bacteria and yeast properties of the surfactant was determined by index of the minimum inhibitory concentration (MIC). The number of attached cells was determined spectrophotometrically.

RESULTS

The dependence of surfactant antimicrobial and anti-aghesive activity on the degree of glycerol purification (purified, technical), as well as the duration of N. vaccinii IMV B-7405 cultivation on these substrates was established. MIC against studied test cultures surfactants, synthesized on technical glycerol during 5 days, was 15–121 μg/ml, that lower than MIC of surfactant obtained on purified substrate (22.5−180 μg/ml). Increasing duration of N. vaccinii ІMV B-7405 cultivation accompanied by rise the MIC against some test cultures surfactants synthesized on both technical and purified glycerol. Adhesion of the bacteria Escherichia coli ІEM-1, Bacillus subtilis BT-2 (vegetative cells and spores) and the yeast Candida albicans Д-6 on abiotic surfaces treated with surfactants synthesized on technical glycerol for both 5 and 7 days, was an average of 11−12 % less than after materials treatment with surfactants obtained on the purified substrate.

CONCLUSIONS

Increasing activity of NADP+-dependent glutamate dehydrogenase − key enzyme of aminolipids biosynthesis (effective antimicrobial and anti-adhesion agents) in the presence of K+ and Na+ may indicate the possibility of biosynthesis intensification of these components of surfacrants complex under N. vaccinii ІMV B-7405 cultivation on technical glycerol, which is characterized by a high content of sodium and potassium cations. Replacing refined glycerol on byproduct of biodiesel production will not only reduce the cost of N. vaccinii ІMV B-7405 surfactant biosynthesis, but also to obtain the final product with high antiadhesive and antimicrobial activity.

[ANTIMICROBIAL ACTION OF NOCARDIA VACCINII IMV B-7405 SURFACTANTS]

AIM

To study the effect of Nocardia vaccinii IMV B-7405 surfactants on some bacteria (including pathogens of genera Proteus, Staphylococcus, Enterobacter), yeast of Candida species and fungi (Aspergillus niger R-3, Fusarium culmorum T-7).

METHODS

The antimi- crobial properties of surfactant were determined in suspension culture by Koch method and also by index of the minimum inhibitory concentration. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1).

RESULTS

It is shown that the antimicrobial properties of N. vaccinii IMV B-7405 surfactant depended on the degree of purification (supernatant, solution of surfactant), concentration and exposure. Survival of Escherichia coli IEM-1 and Bacillus subtilis BT-2 (both vegetative cells and spores) after treatment for 1-2 hours with surfactants solution and the supernatant (the surfactant concentration 21 µg/ml) was 3-28%. Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants on studied bacteria, yeast and micromycetes were 11.5-85.0; 11.5-22.5 and 165.0-325.0 µ/ml respectively.

CONCLUSIONS

Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants are comparable to those of the known microbial surfactants. The possibility of using the supernatant of culture liquid as an effective antimicrobial agent noticeably simplifies and reduces the cost of the technology of its obtaining.

Nocarbenzoxazoles A-G, Benzoxazoles Produced by Halophilic Nocardiopsis lucentensis DSM 44048

Seven new benzoxazole derivatives, nocarbenzoxazoles A-G (1-7), were isolated from the halophilic strain Nocardiopsis lucentensis DSM 44048. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic data, HRESIMS, and X-ray single-crystal diffraction. The isolated compounds were assayed for their cytotoxicity against a panel of human tumor cell lines (HepG2, MDA-MB-231, MDA-MB-435, HeLa, and PC3). Compounds 1-6 were found to have modest or no activity. Compound 7 showed selective activity against HepG2 and HeLa with IC₅₀ values of 3 and 1 μM, respectively.

Transport across the outer membrane porin of mycolic acid containing actinomycetales: Nocardia farcinica

The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Nocardia farcinica, which forms a hydrophilic pathway across the cell wall, was characterized. Single channel electrophysiology measurements and liposome swelling assays revealed the permeation of hydrophilic solutes including sugars, amino acids and antibiotics. The cation selective N. farcinica channel exhibited strong interaction with the positively charged antibiotics; amikacin and kanamycin, and surprisingly also with the negatively charged ertapenem. Voltage dependent kinetics of amikacin and kanamycin interactions were studied to distinguish binding from translocation. Moreover, the importance of charged residues inside the channel was investigated using mutational studies that revealed rate limiting interactions during the permeation.

[Antiadhesive properties of the surfactants of Acinetobacter calcoaceticus IMB B-7241, Rhodococcus erythropolis IMB Ac-5017, and Nocardia vaccinii IMB B-7405]

Attachment of the cells of some bacteria, yeasts, and micromycetes to various surfaces (catheters, dentures, plastic, polyvinyl chloride, tiles, and steel) treated with the surfactants fromAcinetobacter calcoace- ticus IMB B-7241, Rhodococcus erythropolis IMB Ac-5017, and Nocardia vaccinii IMB B-7405 was studied. Adhesion of microorganisms to all the studied surfaces depended on the surfactant concentration and purity, kind of surface, and the test culture. Treatment with the surfactants from N. vaccinii IMB B-7405 (0.005- 0.05 mg/mL), A. calcoaceticus IMB B-7241 (0.003-0.036 mg/mL), and R. erythropolis IMB Ac-5017 (0.03- 0.12 mg/mL) resulted in adhesion decreased respectively by 35-75, 60-75, and 25-90% for bacteria (Es- cherichia coli IEM-1, Bacillus subtilis BT-2, etc.), by 80-85, 55-90, and 15-60% for yeasts Candida albicans D-6, and by 40-50, 35-45, and 10-20% for micromycetes (Aspergillus niger P-3 and Fusarium culmorum T-7).

[Effect of surface-active substances of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017, and Nocardia vaccinii K-8 on phytopathogenic bacteria]

The effect of surface-active substances (SAS's) of Acinetobacter calcoaceticus IMV B-7241, Rhodococcus erythropolis IMV Ac-5017, and Nocardia vaccinii K-8 on phytopathogenic bacteria has been studied. It was shown that the survival of cells (10(5)-10(7) in a milliliter) of the Pseudomonas and Xanthomonas phytopathogenic bacteria was found to be 0-33% after treatment with SAS preparations of the IMV Ac-5017 and IMV B-7241 strains for 2 h (0.15-0.4 mg/mL). In the presence of N. vaccinii K-8 SAS preparations (0.085-0.85 mg/mL), the number of cells of the majority of the studied phytopathogenic bacteria decreased by 95-100%. These data show prospects for using microbial SAS's for the construction of ecologically friendly drugs for regulating the number of phytopathogenic bacteria.

A new phenoxazine derivative isolated from marine sediment actinomycetes, Nocardiopsis sp. 236

During screening of marine actinomycetes for anti-mycobacterial activity, a new phenoxazine derivative (1) was isolated, along with 6-phenazinediol (2), 6-methoxy-1-phenazinol (3), nocardamin (4), and 3-pyridinecarboxylic acid (5), from a culture of Nocardiopsis sp. 236 collected from the west Pacific. The chemical structure of 1 was established on the basis of 1D-, 2D-NMR, and HRQ-TOF MS data. All compounds were evaluated for their anti-mycobacterial activity in vitro, and only compounds 2 and 3 exhibited weak activity.

Nocardiamides A and B, two cyclohexapeptides from the marine-derived actinomycete Nocardiopsis sp. CNX037

Two new cyclic hexapeptides, nocardiamides A (1) and B (2), were isolated from the culture broth of marine-derived actinomycete CNX037 strain that was identified as a Nocardiopsis species. The planar structures of nocardiamides A (1) and B (2) were assigned on the basis of 1D and 2D NMR and HRESIMS spectroscopic analyses. Their absolute configurations were deduced by the advanced Marfey's method and chiral-phase HPLC analysis. The challenge of locating two d- and one l-valine residue in 1 and 2 was accomplished by total synthesis using solid-phase peptide synthetic methods. Both 1 and 2 showed negligible antimicrobial activities against seven indicator strains and exhibited no cytotoxicity against HCT-116.

Griseusins F and G, spiro-naphthoquinones from a tin mine tailings-derived alkalophilic Nocardiopsis species

Griseusins F (1) and G (2), two 2a-hydro-8a-(2-oxopropyl)-substituted spiro-naphthoquinones with a previously undescribed C23 polyketide skeleton, were isolated from a Yunnan tin mine tailings-derived alkalophilic actinomycete, Nocardiopsis sp. YIM DT266. Their complete structure assignments with the absolute stereochemistry were elucidated by spectroscopic data, X-ray crystal diffraction, calculation of optical rotation, and CD spectroscopic analysis. Compounds 1 and 2 exhibited strong cytotoxicity (IC50 0.37-0.82 μM) and antibacterial activity (MIC 0.80-1.65 μg/mL) against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) in vitro.

Calcium carbonate mineralization: involvement of extracellular polymeric materials isolated from calcifying bacteria

This study highlights the role of specific outer bacterial structures, such as the glycocalix, in calcium carbonate crystallization in vitro. We describe the formation of calcite crystals by extracellular polymeric materials, such as exopolysaccharides (EPS) and capsular polysaccharides (CPS) isolated from Bacillus firmus and Nocardia calcarea. Organic matrices were isolated from calcifying bacteria grown on synthetic medium--in the presence or absence of calcium ions--and their effect on calcite precipitation was assessed. Scanning electron microscopy observations and energy dispersive X-ray spectrometry analysis showed that CPS and EPS fractions were involved in calcium carbonate precipitation, not only serving as nucleation sites but also through a direct role in crystal formation. The utilization of different synthetic media, with and without addition of calcium ions, influenced the biofilm production and protein profile of extracellular polymeric materials. Proteins of CPS fractions with a molecular mass between 25 and 70 kDa were overexpressed when calcium ions were present in the medium. This higher level of protein synthesis could be related to the active process of bioprecipitation.

Total synthesis and biological evaluation of transvalencin Z

The emerging global epidemic of drug-resistant tuberculosis has created an urgent need to identify novel therapeutic approaches for disease treatment. Transvalencin Z (1) is a natural product from Nocardia transvalensis with relatively potent and selective antimycobacterial activity against Mycobacterium smegmatis, making it an attractive target for structure-activity and mechanism of action studies. The total synthesis of the four possible diastereomers of transvalencin Z was completed (1a-d), and the absolute configurations were defined using chemical synthesis, HPLC retention times, and optical rotation measurements. Surprisingly, none of the transvalencin Z diastereomers exhibited any inhibitory activity against a panel of microbial pathogens, including several species of mycobacteria.

Peptidolipins B-F, antibacterial lipopeptides from an ascidian-derived Nocardia sp

A marine Nocardia sp. isolated from the ascidian Trididemnum orbiculatum was found to produce five new lipopeptides, peptidolipins B-F (1-5), which show distinct similarities to the previously reported L-Val(6) analog of peptidolipin NA. Synthetic modification of peptidolipin E (4) was used to determine the location of an olefin within the lipid chain. The advanced Marfey's method was used to determine the absolute configurations of the amino acids. Peptidolipins B (1) and E (4) demonstrated moderate antibacterial activity against methicillin-resistant Staphylococcus aureus and methicillin-sensitive Staphylococcus aureus.

Study on mechanical properties of a new type micro/nano metal material based on bacteria shape

The functional groups and mechanical properties of Nocadia, a kind of bacteria with submicrometer in diameter and 3-10 microm in length, before and after metallization are determined by fourier transform infrared spectroscopy (FT-IR) and nanoindentation technology. The group -COOH exists on surface of Nocadia and the function groups of Nocadia decreases due to metallization. The elastic modulus of metallized Nocadia, Nocadia and resin is 42.583 GPa, 9.501 GPa and 5.723 GPa, respectively, and the hardness is 1.940 GPa, 0.265 GPa and 0.301 GPa, respectively. There is a great improvement of 5 times in elastic modulus and 9 times in hardness compared with bare Nocadia.

(1)H and (13)C NMR assignments of eight nitrogen containing compounds from Nocardia alba sp.nov (YIM 30243(T))

An unprecedented new natural product named nocarsin A (1), 5H-4a,6,7a-triazacyclopenta[cd]indene-5,7(6H)-dione (1), together with seven known compounds lumichrome (2), cyclo (L-Leu-L-Tyr) (3), cyclo (L-Ala-L-Ile) (4), cyclo (L-Ala-L-Leu) (5), cyclo (L-Val-L-Ala) (6), 5-methyluracil (7) and uracil (8), was isolated from Nocardia alba sp.nov (YIM 30243(T)), which was isolated from a soil sample collected from Yunnan Province, P. R. China. NMR techniques including COSY, HSQC, ROESY, and HMBC were used to elucidate the structures of these compounds. We report the unambiguous assignments of the (1)H and (13)C NMR spectra of the new compound nocarsin A (1).

Nocardia amamiensis sp. nov., isolated from a sugar-cane field in Japan

An actinomycete, strain TT 00-78T, was isolated from soil from a sugar-cane field on Amami Island in Japan, using an SDS/yeast extract pre-treatment method, and the taxonomy was studied using a polyphasic approach. The chemotaxonomic and morphological characterizations clearly demonstrated that the strain belongs to the genus Nocardia. 16S rRNA gene sequencing studies showed that the strain was closely related to the type strains of Nocardia pneumoniae (98.6 %), Nocardia araoensis (98.1 %), Nocardia arthritidis (97.9 %) and Nocardia beijingensis (97.7 %). However, the results of DNA–DNA hybridization and physiological and biochemical tests showed that strain TT 00-78T could be differentiated from its closest phylogenetic relatives both genotypically and phenotypically. Therefore this strain represents a novel species of the genus Nocardia, for which the name Nocardia amamiensis sp. nov. is proposed. The type strain is TT 00-78T (=NBRC 102102T=DSM 45066T=KCTC 19208T).

Nocardia terpenica sp. nov., isolated from Japanese patients with nocardiosis

Two bacterial strains isolated from different hospitals in Japan were subjected to a polyphasic analysis. Strains IFM 0406 and IFM 0706T, producers of novel terpenoid antibiotics, were found to have morphological, biochemical, physiological and chemotaxonomic properties consistent with their classification in the genus Nocardia, except for the presence of MK-8(H4) as one of the predominant menaquinones in addition to the major menaquinone MK-8(H4ω-cyc). The 16S rRNA gene sequence similarity of strains IFM 0406 and IFM 0706T was 99.9 %, and the closest members of Nocardia to these strains were the type strains of Nocardia nova and Nocardia mexicana, showing similarity of 97.5 and 97.1 %, respectively. Based on their characteristic phenotypic and phylogenetic properties, a novel species of the genus Nocardia, Nocardia terpenica sp. nov. is proposed for the two strains. The type strain is IFM 0706T (=JCM 13033T=DSM 44935T=NBRC 100888T).

Nocardichelins A and B, siderophores from Nocardia strain acta 3026

An actinomycete, strain Acta 3026, isolated from mangrove soil was characterized and found to belong to the genus Nocardia. The strain produces two new cytotoxic metabolites, nocardichelins A (1) and B (2). Each of the compounds strongly inhibited human cell lines from gastric adenocarcinoma, breast carcinoma, and hepatocellular carcinoma with GI50 values in a low micromolar to nanomolar range. The structural characterization of the compounds was performed by mass spectrometry and NMR spectroscopy. The nocardichelins represent a new group of siderophores that combine the structural elements of mycobactin-type siderophores from mycobacteria and hydroxamate-type siderophores (desferrioxamine B) produced by streptomycetes. The chromazurol S assay, characteristic for iron(III) complexation, was positive, confirming the role as a siderophore.

Nocardia acidivorans sp. nov., isolated from soil of the island of Stromboli

A Gram-positive, non-spore-forming bacterium (strain GW4-1778T) was isolated from soil of the Italian island of Stromboli. 16S rRNA gene sequence similarity studies showed that strain GW4-1778T is a member of the genus Nocardia, most closely related to Nocardia pseudobrasiliensis (GenBank accession no. DQ659914; 98.6 %), Nocardia nova (Z36930; 98.6 %), Nocardia niigatensis (AB092563; 98.4 %), Nocardia jiangxiensis (AY639902; 98.0 %), Nocardia uniformis (Z46752; 98.0 %) and Nocardia miyunensis (AY639901; 97.8 %). Strain GW4-1778T could be distinguished from any other established Nocardia species by sequence similarity values of less than 97.5 %. Strain GW4-1778T exhibited a quinone system with the predominant compound MK-8 (H4, ω-cycl) (99.5 %) and traces of MK-8 (H4), characteristic for the genus Nocardia. The polar lipid profile of strain GW4-1778T consisted of the predominant compound diphosphatidylglycerol, moderate amounts of phosphatidylethanolamine, phosphatidylinositol, two phosphatidylinositol mannosides, a unknown polar lipid and trace amounts of two unknown lipids and the major fatty acids were C15 : 0, C16 : 0, C17 : 1 ω8c and 10-methyl C17 : 0. The results of DNA–DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW4-1778T from related species with 16S rRNA gene similarities of >97.5 %. Therefore, strain GW4-1778T merits species status, for which the name Nocardia acidivorans sp. nov. is proposed, with the type strain GW4-1778T (=CCUG 53410T=CIP 109315T=DSM 45049T).

Thiols in nitric oxide synthase-containing Nocardia sp. strain NRRL 5646

Mycothiol (MSH) [1-D-myo-inosityl-2-(N-acetyl-l-cysteinyl)amido-2-deoxy-alpha-D-glucopyranoside], isolated as the bimane derivative, was established to be the major thiol in Nocardia sp. strain NRRL 5646, a species most closely related to Nocardia brasiliensis strain DSM 43758(T). Thiol formation and detection of MSH-dependent formaldehyde dehydrogenase activity in cell extracts are relevant to the possible modulation of nitric oxide toxicity generated by strain NRRL 5646.

Isolation and identification of 2alpha,25-dihydroxyvitamin D3, a new metabolite from Pseudonocardia autotrophica 100U-19 cells incubated with Vitamin D3

Pseudonocardia autotrophica converted Vitamin D(3) to 25-hydroxyvitamin D(3) and 1alpha,25-dihydroxyvitamin D(3). The hydroxylation of Vitamin D(3) with P. autotrophica was enhanced by the addition of cyclodextrin. In this microbial hydroxylation, a new Vitamin D(3) metabolite was observed in the reaction mixture of P. autotrophica and Vitamin D(3), and was isolated in a pure form by several steps of chromatography. The structure of the new metabolite was determined to be 2alpha,25-dihydroxyvitamin D(3) by UV, NMR and mass spectroscopic analyses. Biological evaluation of the new metabolite was conducted by means of several experiments.

Stability study on the nitrile hydratase of Nocardia sp. 108: from resting cell to crude enzyme preparation

In recent years, nitrile hydratases (NHases) have drawn increasing attentions due to their critical roles in organic synthesis. In present paper, extensive investigation on the stability and activity of the NHase from Nocardia sp. 108, which is succeed in the industrial application in China, were conducted by the bioconversion of acrylonitrile to acrylamide in a batch manner. Cultivation study demonstrated that biosynthesis of NHase changed significantly with culture time, and the optimal NHase biosynthesis phase was 45 h after inoculation with NHase activity of 1209.8 U/g of biomass. Stability study indicated that crude enzyme preparation both exhibit a good stability when exposed to the pH 7.2 tris-HCl buffer at 4 degrees C for 4 h.

[Peculiarities of cell wall ultrastructure of Nocardia dassonvilei]

Peculiarities of cell wall building and chemical content of Nocardia dassonvilei have been studied in conditions of culture growth and development. It has been established that according to the phases of actinomyces a mass of cell wall changes. In particular, it is maximal in logarithmic phase and minimal - in stationary phase. In the phase of dying an insignificant increase of cell wall is noted. It appears to be a result of the increase of amino acid content in peptic fraction of peptide-glycane in this phase. At the same time it has been established that according to the growth phases, in cell wall of the studied actynomyces the amount of teihoic acid appears to be a changeable value. In particular, it decreases from logarithmic to the phase of dying. The content of cell wall free polysaccharides also changes; their synthesis begins in logarithmic phase, reaches to maximum in stationary phase and is minimal in the phase of dying. According to the results of our investigations it has been established that chemical content of Nocardia dassonvilei cell wall is qualitatively stable in the dynamics of culture growth.

Nocardimicins G, H and I, siderophores with muscarinic M3 receptor binding inhibitory activity from Nocardia nova JCM 6044

In the screening for muscarinic M3 receptor binding inhibitors from microbial secondary metabolites, the extract of Nocardia nova JCM 6044 was found to be highly active. Bioassay-guided isolation led to the identification of three siderophores, nocardimicins G (1), H (2) and I (3). Their chemical structures were determined by spectroscopic analysis using NMR and MS. 1 and 2 inhibited the binding of tritium-labeled N-methylscopolamine to the muscarinic M3 receptor with Ki values of 0.44 microM and 0.37 microM, respectively, whereas 3 showed no inhibition at 10 microM. 1 and 2 also showed weak binding inhibitory activity to the M5 receptor but not to the M1, M2 and M4 receptors at 10 microM.

Nocardimicins A, B, C, D, E, and F, siderophores with muscarinic M3 receptor inhibiting activity from Nocardia sp. TP-A0674

In the screening for muscarinic M3 receptor binding inhibitors from microbial secondary metabolites, the extract of Nocardia sp. TP-A0674 was found to be highly active. Bioassay-guided fractionation of it led to the isolation of six new siderophores, nocardimicins A (1), B (2), C (3), D (4), E (5), and F (6), as active principles. Their chemical structures were determined by spectroscopic and degradation analysis. Of these congeners, nocardimicin B (2) inhibited the binding of tritium-labeled N-methylscopolamine to the muscarinic M3 receptor most potently with a Ki value of 0.13 microM. Compound 2 showed more selective activity to M3 and M4 receptors than other subtypes.

Nocardia elegans sp. nov., a member of the Nocardia vaccinii clade isolated from sputum

Two bacterial isolates from the sputa of a patient with a pulmonary infection were subjected to a polyphasic taxonomic study. Chemotaxonomic investigations revealed the presence of cell-wall chemotype IV and mycolic acids consistent with the profile for the genus Nocardia. Comparative 16S rRNA gene sequencing showed that these isolates constitute a distinct subline within the genus Nocardia, displaying 99·6–95·5 % sequence similarities with established species. However, DNA–DNA hybridization studies demonstrated unambiguously that the isolates are genealogically distinct from closely related species, namely Nocardia veterana and Nocardia africana, which show high levels of 16S rRNA sequence similarity (99·2 and 99·6 % sequence similarity, respectively). On the basis of both phenotypic and phylogenetic evidence, it is proposed that these isolates be classified as a novel species of the genus Nocardia, for which the name Nocardia elegans sp. nov. is proposed. The type strain is IMMIB N-402T (=CCUG 50200T=CIP 108553T).

Nocardia polyresistens sp. nov

A novel actinomycete strain YIM 33361T was isolated from a soil sample collected from Yunnan, China. Comparative 16S rRNA gene sequencing showed that the strain constituted a distinct subclade within the genus Nocardia, displaying more than 3 % sequence divergence from established species. Based on its morphological, chemotaxonomic, phenotypic and genotypic characteristics, strain YIM 33361T (=CCTCC AA 204004T=KCTC 19027T) is proposed as the type strain of a novel species, Nocardia polyresistens sp. nov.

Nocardia shimofusensis sp. nov., isolated from soil, and Nocardia higoensis sp. nov., isolated from a patient with lung nocardiosis in Japan

Three actinomycete strains isolated from soils and one strain isolated from a patient with lung nocardiosis in 1999 and 2001 in Japan have been provisionally assigned to the genus Nocardia on the basis of morphological criteria. These isolates were further investigated to determine their specific taxonomic status. Detailed chemotaxonomic characterization and 16S rRNA gene sequence analysis of these isolates confirmed that they belong to the genus Nocardia. The 16S rRNA gene sequences of the four strains were most similar to that of Nocardia farcinica. However, the sequence similarity values between these four strains and N. farcinica were <98.9 %. These four strains were susceptible to 5-fluorouracil, and they have the ability to decompose urea, which is a very characteristic trait. Furthermore, DNA-DNA relatedness data revealed that IFM 10311(T), IFM 10312 and IFM 10313 comprise a single novel species of Nocardia, that IFM 10084(T) represents another novel species of Nocardia and that these two novel species could be distinguished from N. farcinica. The names Nocardia shimofusensis sp. nov. and Nocardia higoensis sp. nov. are proposed, with IFM 10311(T) (=NBRC 100134(T)=JCM 12122(T)=DSM 44733(T)) and IFM 10084(T) (=NBRC 100133(T)=JCM 12121(T)=DSM 44732(T)) as the respective type strains.

NMR spectroscopic analysis of new spiro-piperidylrifamycins

New spiro-piperidylrifamycin derivatives are presented. These compounds were synthesized from the reaction of 3-amino-4-iminorifamycin S and enantiomerically pure 4-piperidones, which generate diasteroisomeric rifabutin analogues with a new stereocentre at the spiranic carbon. The (1)H and (13)C NMR spectra of these new compounds, and also the configuration of the new stereogenic centres, were assigned using 2D NMR spectroscopic techniques. A preliminary study of the (1)H and (13)C NMR spectra of the starting compounds rifamycin S, 3-amino-4-iminorifamycin S and the related rifabutin was also carried out and as a result, their previously published (13)C NMR data were corrected.

Nocardia aobensis Sp. Nov., isolated from patients in Japan

Five clinical isolates, strains IFM 0137, 0372(T), 0496, 0556, and 0952, were provisionally assigned to the genus Nocardia based on morphological criteria. Nearly complete 16S rDNA sequences were determined for these strains. These data showed that they are most similar to that of Nocardia africana, Nocardia cerradoensis and Nocardia veterana. However, DNA-DNA relatedness data showed that the five strains were of a single species and were distinguishable from N. africana, N. cerradoensis and N. veterana. Therefore, these strains represent a new species within the genus Nocardia. The designation of these five strains is Nocardia aobensis sp. nov. The type strain is IFM 0372(T) (=NBRC 100429(T)=JCM 12352(T)=DSM 44805(T)).

Brasilibactin A, a cytotoxic compound from actinomycete Nocardia brasiliensis

A new cytotoxic compound, brasilibactin A (1), has been isolated from the actinomycete Nocardia brasiliensis IFM 0995, and the structure was elucidated on the basis of spectroscopic data and chemical means.

Nocardia pigrifrangens sp. nov., a novel actinomycete isolated from a contaminated agar plate

A polyphasic study was undertaken to establish the taxonomic position of an actinomycete strain isolated from a contaminated agar plate. The strain, designated 7031T, had morphological and chemotaxonomic properties typical of the genus Nocardia. An almost-complete 16S rRNA gene sequence determined for the strain was aligned with available sequences for nocardiae, and phylogenetic trees were inferred using three tree-generating algorithms. Strain 7031T clustered with the type strains of Nocardia carnea and Nocardia flavorosea, showing low 16S rRNA gene sequence similarities to these species (97.2 and 97.5 %, respectively). The strain was also distinguished from the closest species by a range of phenotypic properties. It is proposed that the strain be recognized as a novel species of Nocardia, Nocardia pigrifrangens sp. nov., the type strain of which is 7031T (= AS 4.1808T = JCM 11884T).

Brasilicardins B–D, new tricyclic terpernoids from actinomycete Nocardia brasiliensis

Three new tricyclic terpenoids, brasilicardins B-D (2-4), were isolated together with brasilicardin A (1), a potent immunosuppressive compound, from the cultured broth of a pathogenic actinomycete Nocardia brasiliensis IFM0406, and the structures and stereochemistry were determined by spectroscopic data and a single crystal X-ray diffraction analysis. The immunosuppressive and cytotoxic activities of 2-4 were examined in the comparison with 1.

Transvalencin A, a Thiazolidine Zinc Complex Antibiotic Produced by a Clinical Isolate of Nocardia transvalensis: II.Structure Elucidation

A novel antifungal antibiotic, transvalencin A, is produced by Nocardia transvalensis IFM 10065 isolated from a patient with actinomycotic mycetoma in Japan. The antibiotic structure was elucidated using NMR, mass spectrometric investigations, and X-ray crystallographic analysis. Transvalencin A is a 1:1 complex of a zinc and an organic acid with a phenolic substituent. Transvalencin A is comprised of o-substituted p-chlorophenol, tetrasubstituted oxazoline, disubstituted thiazolyl-N-methylthiazolidine and monosubstituted N-methylthiazolidine.

Kribbella antibiotica sp. nov., a Novel Nocardioform Actinomycete Strain Isolated from Soil in Yunnan, China

A novel nocardioform actinomycete strain YIM 31530T was isolated from a soil in Yunnan, China. Based on the results of phenotypic characteristics, phylogenetic studies and DNA-DNA hybridization results, strain YIM 31530T should be assigned to a new species of the genus Kribbella, for which the name Kribbella antibiotica sp. nov. is proposed. The type strain is YIM 31530T(= CCTCC AA001021T = DSM 15501T). The GenBank accession number for the sequence reported in this paper is AY082063.

Transvalencin A, a Thiazolidine Zinc Complex Antibiotic Produced by a Clinical Isolate of Nocardia transvalensis: I.Taxonomy, Fermentation, Isolation and Biological Activities

A new thiazolidine-type antibiotic with zinc in its structure, designated transvalencin A, was isolated from Nocardia sp. IFM 10065, a clinical isolate from a patient with actinomycotic mycetoma. The strain was identified as Nocardia transvalensis based on its morphological, phenotypic and phylogenetic characteristics. Transvalencin A showed antimicrobial activity against fungi such as Trichophyton mentagrophytes and Cryptococcus neoformans. The antibiotic is also active against Gram-positive bacteria such as Micrococcus luteus. We observed higher activity for fungi in an acidic medium than in a neutral medium.

Nocathiacins, new thiazolyl peptide antibiotics from Nocardia sp. I. Taxonomy, fermentation and biological activities

Thiazolyl peptide antibiotics, nocathiacin I, II and III, were identified in a culture of Nocardia sp. WW-12651 (ATCC 202099). They exhibit potent in vitro activity (ng/ml) against a wide spectrum of gram-positive bacteria, including multiple-drug resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), multi-drug resistant Enterococcus faecium (MREF) and fully penicillin-resistant Streptococcus pneumoniae (PRSP), and demonstrate excellent in vivo efficacy in a systemic Staphylococcus aureus infection mice model.

Nocathiacins, new thiazolyl peptide antibiotics from Nocardia sp. II. Isolation, characterization, and structure determination

A new group of thiazolyl peptide antibiotics, the nocathiacins, was isolated from cultured broth of Nocardia sp. The major analogs nocathiacins I-III (1-3) were purified using silica gel and Sephadex LH-20 chromatography techniques. The structures of nocathiacins I-III were determined by spectroscopic (2D-NMR, MSn) methods, and share structural similarities to glycothiohexide-alpha (4).