Paenidigyamycin A, Potent Antiparasitic Imidazole Alkaloid from the Ghanaian Paenibacillus sp. DE2SH.

A new alkaloid paenidigyamycin A (1) was obtained from the novel Ghanaian Paenibacillus sp. isolated from the mangrove rhizosphere soils of the Pterocarpus santalinoides tree growing in the wetlands of the Digya National Park, Ghana. Compound 1 was isolated on HPLC at tR = 37.0 min and its structure determined by MS, 1D, and 2D-NMR data. When tested against L. major, 1 (IC50 0.75 µM) was just as effective as amphotericin B (IC50 0.31 µM). Against L. donovani, 1 (IC50 7.02 µM) was twenty-two times less active than amphotericin B (IC50 0.32 µM), reinforcing the unique effectiveness of 1 against L. major. For T. brucei brucei, 1 (IC50 0.78 µM) was ten times more active than the laboratory standard Coptis japonica (IC50 8.20 µM). The IC50 of 9.08 µM for 1 against P. falciparum 3d7 compared to artesunate (IC50 36 nM) was not strong, but this result suggests the possibility of using the paenidigyamycin scaffold for the development of potent antimalarial drugs. Against cercariae, 1 showed high anticercaricidal activity compared to artesunate. The minimal lethal concentration (MLC) and minimal effective concentration (MEC) of the compound were 25 and 6.25 µM, respectively, while artesunate was needed in higher quantities to produce such results. However, 1 (IC50 > 100 µM) was not active against T. mobilensis.

Extracellular Synthesis and Characterization of Gold Nanoparticles Using Mycobacterium sp. BRS2A-AR2 Isolated from the Aerial Roots of the Ghanaian Mangrove Plant, Rhizophora racemosa.

Through the use of genomes that have undergone millions of years of evolution, marine Actinobacteria are known to have adapted to rapidly changing environmental pressures. The result is a huge chemical and biological diversity among marine Actinobacteria. It is gradually becoming a known fact that, marine Actinobacteria have the capability to produce nanoparticles which have reasonable sizes and structures with possible applications in biotechnology and pharmacology. Mycobacterium sp. BRS2A-AR2 was isolated from the aerial roots of the mangrove plant Rhizophora racemosa. The Mycobacterium was demonstrated for the first time ever to produce AuNPs with sizes that range between 5 and 55 nm. The highest level absorbance of the biosynthesized AuNPs was typical for actinobacterial strains (2.881 at 545 nm). The polydispersity index was measured as 0.207 in DLS and the zeta potential was negatively charged (- 28.3 mV). Significant vibration stretches were seen at 3314, 2358, 1635 and 667 cm-1 in FT-IR spectra. This demonstrated the possible use of small aliphatic compounds containing -COOH, -OH, -Cl and -NH2 functional groups in the stabilization of the AuNPs. The effect of the biosynthesized AuNPs on HUVEC and HeLA cell lines was measured at 48 h. IC50 values were determined at 3500 µg/ml concentration for HUVEC and HeLA cell lines at 45.25 and 53.41% respectively.

Toxicity of Engineered Nickel Oxide and Cobalt Oxide Nanoparticles to Artemia salina in seawater.

In this study, the effects of exposure to engineered nickel oxide (NiO 40-60 nm) and cobalt oxide (CoO <100 nm) nanoparticles (NP) were investigated on Artemia salina. Aggregation and stability of the aqueous NP suspensions were characterized by DLS and TEM. Acute exposure was conducted on nauplii (larvae) in seawater in a concentration range from 0.2 to 50 mg/L NPs for 24 h (short term) and 96 h (long term). The hydrodynamic diameters of NiO and CoO NPs in exposure medium were larger than those estimated by TEM. Accumulation rate of NiO NPs were found to be four times higher than that of CoO NPs under the same experimental conditions. Examinations under phase contrast microscope showed that the nanoparticles accumulated in the intestine of artemia, which increased with increasing exposure concentration. Differences were observed in the extent of dissolution of the NPs in the seawater. The CoO NPs dissolved significantly while NiO NPs were relatively more stable. Oxidative stress induced by the NP suspensions was measured by malondialdehyde assay. Suspensions of NiO NPs caused higher oxidative stress on nauplii than those of CoO NPs. The results imply that CoO and NiO NPs exhibit toxicity on artemia (e.g., zooplankton) that are an important source of food in aquatic food chain.

Chronic exposure of tilapia (Oreochromis niloticus) to iron oxide nanoparticles: Effects of particle morphology on accumulation, elimination, hematology and immune responses.

Effects of chronic exposure to alpha and gamma iron oxide nanoparticles (α-Fe2O3 and γ-Fe2O3 NPs) were investigated through exposure of tilapia (Oreochromis niloticus) to 0.1, 0.5 and 1.0mg/L (9.2×10(-4), 4.6×10(-3) and 9.2×10(-3)mM) aqueous suspensions for 60days. Fish were then transferred to NP-free freshwater and allowed to eliminate ingested NPs for 30days. The organs, including gills, liver, kidney, intestine, brain, spleen, and muscle tissue of the fish were analyzed to determine the accumulation, physiological distribution and elimination of the Fe2O3 NPs. Largest accumulation occurred in spleen followed by intestine, kidney, liver, gills, brain and muscle tissue. Fish exposed to γ-Fe2O3 NPs possessed significantly higher Fe in all organs. Accumulation in spleen was fast and independent of NP concentration reaching to maximum levels by the end of the first sampling period (30th day). Dissolved Fe levels in water were very negligible ranging at 4-6µg/L for α-Fe2O3 and 17-21µg/L for γ-Fe2O3 NPs (for 1mg/L suspensions). Despite that, Fe levels in gills and brain reflect more dissolved Fe accumulation from metastable γ-Fe2O3 polymorph. Ingested NPs cleared from the organs completely within 30-day elimination period, except the liver and spleen. Liver contained about 31% of α- and 46% of γ-Fe2O3, while spleen retained about 62% of α- and 35% of the γ-polymorph. No significant disturbances were observed in hematological parameters, including hemoglobin, hematocrit, red blood cell and white blood cell counts (p>0.05). Serum glucose (GLU) levels decreased in treatments exposed to 1.0mg/L of γ-Fe2O3 NPs at day 30 (p<0.05). In contrast, GLU levels increased during the elimination period for 1.0mg/L α-Fe2O3 NPs treatments (p<0.05). Transient increases occurred in glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and lactate dehydrogenase (LDH). Serum Fe levels did not change during exposure (p>0.05), but increased significantly within elimination period due to mobilization of ingested NPs from liver and spleen to blood. Though respiratory burst activity was not affected (p>0.05), lysozyme activity (LA) was suppressed suggesting an immunosuppressive effects from both Fe2O3 NPs (p<0.05). In contrast, myeloperoxidase (MPO) levels increased significantly in treatments exposed to α-Fe2O3 NPs (p<0.05), and the effect from γ-polymorph was marginal (p≥0.05). The results indicate that morphological differences of Fe2O3 NPs could induce differential uptake, assimilation and immunotoxic effects on O. niloticus under chronic exposure.

Influence of Alpha and Gamma-Iron Oxide Nanoparticles on Marine Microalgae Species.

The effects of alpha-iron oxide (α-Fe2O3) and gamma-iron oxide (γ-Fe2O3) nanoparticles (NPs) on marine microalgae species (Nannochloropsis sp. and Isochrysis sp.) were investigated in this study. Both Fe2O3 NPs covered the surface of algae with the agglomerates of the nanoparticles. This form of physical NP toxicity significantly decreased the sizes of phytoplankton. Both NPs were toxic to the tested algal species, while α-Fe2O3 showed less toxicity than γ-Fe2O3 NPs for both algal species. A comparative analysis of growth data of the two algal species treated with α-Fe2O3 or γ-Fe2O3 NPs revealed that Isochrysis sp. are more sensitive than Nannochloropsis sp. Toxicity of these widely used NPs to primary producers forming the base of the food chain in aquatic environments might result in widespread adverse effects on aquatic environmental health.

Butrepyrazinone, a new pyrazinone with an unusual methylation pattern from a Ghanaian Verrucosispora sp. K51G.

We report the structural characterization of a new pyrazinone analogue; butrepyrazinone, which was isolated from a new actinomycete strain Verrucosispora sp. K51G recovered from Ghanaian mangrove river sediment. Spectroscopy-guided fractionation led to the isolation of a compound from the fermentation culture and a combination of NMR spectroscopy, high-resolution mass spectrometry and computer-aided calculations revealed that butrepyrazinone (10) possesses an unusual methylation pattern on the pyrazinone ring. Butrepyrazinone (10), however, displayed no antibacterial activity against Gram-positive S. aureus ATCC 25923, the Gram-negative E. coli ATCC 25922 and a panel of clinical isolates of methicillin-resistant S. aureus (MRSA) strains, suggesting that 10 may act as a signal molecule for this strain. Although the same molecule has been synthesized previously, this is the first report to disclose the discovery of butrepyrazinone (10) from nature.

Nocardia sungurluensis sp. nov., isolated from soil.

A novel Gram-reaction-positive, rod-shaped, non-motile and mycolic acid-containing strain, CR3272T, isolated from soil, was studied using a polyphasic approach. The organism showed a combination of chemotaxonomic and morphological properties typical of the genus Nocardia. The cell wall contained meso-diaminopimelic acid (type IV) and whole-cell sugars were galactose, glucose, arabinose and xylose. The predominant menaquinone was MK-8(H4cyc). The major phospholipids were diphosphatidylglycerol and phosphatidylinositol mannosides. Major fatty acids were C16:0, C18:1cis9, C18:0 10-methyl (TBSA) and C16:1cis9. The novel strain formed distinct phyletic line in the Nocardia 16S rRNA gene tree and was closely associated with Nocardia goodfellowii A2012T (98.6% 16S rRNA gene sequence similarity), Nocardia alba YIM 30243T (98.5%) and Nocardia caishijiensis F829T (97.9%). However, DNA-DNA relatedness values and phenotypic data demonstrated that strain CR3272T was clearly distinguished from all closely related species of the genus Nocardia. It is concluded that the organism be classified as representing a novel species of the genus Nocardia, for which the name Nocardia sungurluensis is proposed. The type strain is CR3272T (=DSM 45714T=KCTC 29094T).

Lechevalieria nigeriaca sp. nov., isolated from arid soil.

A novel actinobacterium, designated strain NJ2035(T), was isolated from soil collected from Abuja, Nigeria and was characterized to determine its taxonomic position. The isolate was found to have chemical and morphological properties associated with members of the genus Lechevalieria. Phylogenetic analyses based on almost-complete 16S rRNA gene sequences indicated that the isolate was closely related to members of the genus Lechevalieria, and was shown to form a distinct phyletic line in the Lechevalieria phylogenetic tree. Strain NJ2035(T) was most closely related to Lechevalieria roselyniae C81(T), Lechevalieria atacamensis C61(T) and Lechevalieria deserti C68(T) (98.5 % 16S rRNA gene sequence similarity). Sequence similarities with other members of the genus Lechevalieria were less than 98.2 %. The cell wall of the novel strain contained meso-diaminopimelic acid, and galactose, mannose and rhamnose as the diagnostic sugars. The predominant menaquinone was MK-9(H4). The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol. DNA-DNA relatedness and phenotypic data showed that the novel isolate and L. roselyniae C81(T), L. atacamensis C61(T) and L. deserti C68(T) belong to distinct genomic species. On the basis of data from this taxonomic study using a polyphasic approach, strain NJ2035(T) represents a novel species of the genus Lechevalieria, for which the name Lechevalieria nigeriaca sp. nov. is proposed. The type strain is NJ2035(T) ( = DSM 45680(T) = KCTC 29057(T) = NRRL B-24881(T)).

Methylobacterium tarhaniae sp. nov., isolated from arid soil.

A reddish-orange-pigmented, Gram-stain-negative, aerobic, facultatively methylotrophic strain, N4211(T), isolated from arid soil, collected from Abuja, Nigeria, was analysed by using a polyphasic approach. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain N4211(T) belonged to the genus Methylobacterium. Strain N4211(T) was most closely related to Methylobacterium aquaticum GR16(T) (98.56 %), Methylobacterium platani PMB02(T) (97.95 %) and Methylobacterium variabile GR3(T) (97.2 %), and the phylogenetic similarities to all other species of the genus Methylobacterium with validly published names were less than 97.0 %. The major ubiquinones detected were Q-10. The major fatty acids were summed feature 7 (C18 : 1 cis11/t9/t6). The DNA G+C content was 67.3 mol%. DNA-DNA relatedness of strain N4211(T) and the most closely related strains M. aquaticum DSM 16371(T) and M. platani KCTC 12901(T) were 60.0 and 48.2 %, respectively. On the basis of phenotypic, phylogenetic and DNA-DNA hybridization data, strain N4211(T) is assigned to a novel species of the genus Methylobacterium for which the name Methylobacterium tarhaniae sp. nov. is proposed. The type strain is N4211(T)( = KCTC 23615(T) = DSM 25844(T)).

Nonomuraea jabiensis sp. nov., isolated from arid soil.

A novel actinomycete, strain A4036(T), was isolated from a soil sample collected from the Jabi district in Abuja, Nigeria. The taxonomic position of strain A4036(T) was established using a combination of genotypic and phenotypic analyses. The organism formed extensively branched substrate and aerial hyphae that generated spiral chains of spores with warty surfaces. The cell wall contained meso-diaminopimelic acid and the cell-wall sugars were glucose, madurose, mannose and ribose. The predominant menaquinone was MK-9(H(4)). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylmethylethanolamine, phosphatidylinositol mannoside, hydroxy-phosphatidylethanolamine, hydroxy-phosphatidylmethylethanolamine, two unidentified phospholipids and four unknown glucosamine-containing phospholipids. The major cellular fatty acids were iso-C(16 : 0) 2-OH, iso-C(16 : 0) and 10-methyl C(17 : 0). On the basis of 16S rRNA gene sequence similarity studies, strain A4036(T) grouped in the genus Nonomuraea, being most closely related to Nonomuraea angiospora IFO 13155(T) (99.05 %), Nonomuraea candida HMC10(T) (98.78 %), Nonomuraea kuesteri GW 14-1925(T) (98.49 %), Nonomuraea endophytica YIM 65601(T) (98.42 %), Nonomuraea maheshkhaliensis 16-5-14(T) (98.40 %), Nonomuraea turkmeniaca DSM 43926(T) (98.38 %), Nonomuraea helvata IFO 14681(T) (98.29 %), Nonomuraea rubra DSM 43768(T) (98.10 %) and Nonomuraea salmonea DSM 43678(T) (98.06 %). Levels of 16S rRNA gene sequence similarity to the type strains of other species of the genus Nonomuraea were <98 %. Despite the high 16S rRNA gene sequence similarities, DNA-DNA relatedness values and phenotypic data demonstrated that strain A4036(T) was clearly distinguished from all closely related species of the genus Nonomuraea. Thus, this isolate is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea jabiensis sp. nov. is proposed. The type strain is A4036(T) (= DSM 45507(T) = KCTC 19870(T)).

Amycolatopsis magusensis sp. nov., isolated from soil.

A novel actinomycete, designated strain KT2025(T), was isolated from arid soil collected from Magusa, northern Cyprus. The taxonomic position of the novel strain was established by using a polyphasic approach. The organism had chemical and morphological features consistent with its classification in the genus Amycolatopsis. Phylogenetic analyses based on 16S rRNA gene sequences supported the classification of the isolate in the genus Amycolatopsis and showed that the organism formed a cluster with Amycolatopsis nigrescens CSC17-Ta-90(T), Amycolatopsis minnesotensis 32U-2(T), Amycolatopsis sacchari DSM 44468(T) and Amycolatopsis dongchuanensis YIM 75904(T). 16S rRNA gene sequence similarity analysis indicated that strain KT2025(T) was most closely related to Amycolatopsis lurida DSM 43134(T) (97.5 %), Amycolatopsis keratiniphila subsp. keratiniphila DSM 44409(T) (97.4 %), Amycolatopsis keratiniphila subsp. nogabecina DSM 44586(T) (97.1 %), Amycolatopsis nigrescens DSM 44992(T) (97.1 %), Amycolatopsis azurea DSM 43854(T) (97.1 %) and Amycolatopsis minnesotensis DSM 44988(T) (96.9 %). The organism was found to have chemical features typical of members of the genus Amycolatopsis such as meso-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan, and arabinose and galactose as diagnostic sugars. The predominant menaquinone was MK-9(H4). The polar lipids detected were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and hydroxy-phosphatidylethanolamine. The major fatty acids were iso-C16 : 0, iso-C15 : 0 and iso-C14 : 0. The G+C content of the genomic DNA was 70.8 mol%. Phenotypic data clearly distinguished the isolate from its closest relatives. The combined genotypic and phenotypic data and low levels of DNA-DNA relatedness with its closest relatives indicated that strain KT2025(T) represents a novel species of the genus Amycolatopsis, for which the name Amycolatopsis magusensis sp. nov. is proposed. The type strain is KT2025(T) ( = DSM 45510(T) = KCTC 29056(T)).

Streptosporangium anatoliense sp. nov., isolated from soil in Turkey.

A novel actinobacterium, strain N9999(T), was isolated from soil and its taxonomic position determined using a polyphasic approach. The organism formed abundant aerial hyphae that differentiated into spherical spore vesicles. The cell wall contained meso-diaminopimelic acid; the whole-cell sugars were galactose, glucose, mannose, madurose and ribose; the predominant menaquinones MK-9 (H(2)) and MK-9 (H(4)); the major phospholipids phosphatidylethanolamine, diphosphatidylglycerol, a phosphaglycolipid and phosphatidylinositol mannosides; while the cellular fatty acids were rich in iso-C(14:0), C(15:0), cis-9-C(17:1), iso-C(16:0) and 10-methyl C(17:0) components. Phylogenetic analyses based on an almost complete 16S rRNA gene sequence indicated that strain N9999(T) was closely related to a group that consisted of Streptosporangium pseudovulgare DSM 43181(T) and Streptosporangium nondiastaticum DSM 43848(T). However, DNA-DNA relatedness and phenotypic data demonstrated that strain N9999(T) was clearly distinguished from all closely related Streptosporangium species. The combined genotypic and phenotypic data demonstrate conclusively that the isolate should be classified as a new species of Streptosporangium.

Actinoplanes abujensis sp. nov., isolated from Nigerian arid soil.

A novel actinobacterial strain, A4029T, isolated from arid soil of Abuja, Nigeria, and provisionally assigned to the genus Actinoplanes, was subjected to a polyphasic taxonomic study. 16S rRNA gene sequence similarity studies showed that strain A4029T belonged to the genus Actinoplanes, being most closely related to Actinoplanes brasiliensis DSM 43805T (98.9 %) and Actinoplanes deccanensis DSM 43806T (98.0 %); similarity to other type strains of the genus Actinoplanes ranged from 96.2 to 97.9 %. Chemotaxonomic data [major menaquinone MK-9(H4); major polar lipids phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol; characteristic sugars arabinose and xylose; major fatty acids iso-C15:0, anteiso-C15:0, iso-C16:0, C17:1ω9c and iso-C14:0] confirmed the affiliation of strain A4029T to the genus Actinoplanes. The results of DNA-DNA hybridizations and phylogenetic analysis, together with phenotypic and biochemical test data, allowed strain A4029T to be differentiated from strains of other Actinoplanes species. Therefore, strain A4029T represents a novel species, for which the name Actinoplanes abujensis sp. nov. is proposed, with A4029T (=DSM 45518T=NRRL B-24835T=KCTC 19984T) as the type strain.

Nocardia goodfellowii sp. nov. and Nocardia thraciensis sp. nov., isolated from soil.

The taxonomic position of two soil actinomycetes, strains A2012(T) and A2019(T), isolated from Turkish soils, was determined using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that the strains belonged to the family Nocardiaceae. Strains A2012(T) and A2019(T) were most closely related to Nocardia caishijiensis DSM 44831(T) (98.9 %) and Nocardia mexicana CIP 108295(T) (98.6 %), respectively; similarity to other type strains of the genus Nocardia ranged from 96.9 to 97.9 %. However, DNA-DNA relatedness and phenotypic data demonstrated that strains A2012(T) and A2019(T) could be clearly distinguished from members of the most closely related Nocardia species. It is evident from the genotypic and phenotypic data that the two isolates represent two novel species of the genus Nocardia. It is proposed, therefore, that strains A2012(T) and A2019(T) be classified in the genus Nocardia as representatives of Nocardia goodfellowii sp. nov. (type strain A2012(T) = DSM 45516(T) = NRRL B-24833(T) = KCTC 19986(T)) and Nocardia thraciensis sp. nov. (type strain A2019(T) = DSM 45517(T) = NRRL B-24834(T) = KCTC 19985(T)), respectively.

Actinomadura geliboluensis sp. nov., isolated from soil.

A novel actinobacterium, strain A8036(T), isolated from soil, was investigated by using a polyphasic taxonomic approach. The organism formed extensively branched substrate hyphae that generated spiral chains of spores with irregular surfaces. The cell wall contained meso-diaminopimelic acid (type III) and cell-wall sugars were glucose, madurose, mannose and ribose. The predominant menaquinones were MK-9(H(6)) and MK-9(H(4)). The phospholipids were diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The major cellular fatty acids were iso-C(16:0), C(17:1)cis9, C(16:0), C(15:0) and 10-methyl C(17:0). Based on 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of strain A8036(T) were Actinomadura meyerae DSM 44715(T) (99.23% similarity), Actinomadura bangladeshensis DSM 45347(T) (98.9%) and Actinomadura chokoriensis DSM 45346(T) (98.3%). However, DNA-DNA relatedness and phenotypic data demonstrated that strain A8036(T) could be clearly distinguished from the type strains of all closely related Actinomadura species. Strain A8036(T) is therefore considered to represent a novel species of the genus Actinomadura, for which the name Actinomadura geliboluensis sp. nov. is proposed. The type strain is A8036(T) ( = DSM 45508(T) = KCTC 19868(T)).