Actinobacteria Research Papers - Academia.edu (original) (raw)

The aim of our study was to determine the efficacy of three different adsorbents, inorganic (modified zeolite), organic (esterified glucomannans) and mixed (inorganic and organic components, with the addition of enzymes), in protecting... more

The aim of our study was to determine the efficacy of three different adsorbents, inorganic (modified zeolite), organic (esterified glucomannans) and mixed (inorganic and organic components, with the addition of enzymes), in protecting broilers from the toxic effects of ochratoxin A in feed. Broilers were fed diets containing 2 mg/kg of ochratoxin A (OTA) and supplemented with adsorbents at the recommended concentration of 2 g/kg for 21 days. The presence of OTA led to a notable reduction in body weight, lower weight gain, increased feed conversion and induced histopathological changes in the liver and kidneys. The presence of inorganic, organic and mixed adsorbents in contaminated feed only partially reduced the negative effects of OTA on the broiler performances. Broilers that were fed with adsorbent-supplemented feed reached higher body weight (17.96%, 19.09% and 13.59%), compared to the group that received only OTA. The presence of adsorbents partially alleviated the reduction i...

The investigation of the microbial community of Lake Baikal by the methods of general and molecular microbiology showed that culturable bacterial strains were represented by various known genera. The lake water contains a great number of... more

The investigation of the microbial community of Lake Baikal by the methods of general and molecular microbiology showed that culturable bacterial strains were represented by various known genera. The lake water contains a great number of bacterial morphotypes, as revealed by electron microscopy, and a great diversity of nonculturable microorganisms belonging to different phylogenetic groups, as revealed by 16S rRNA gene fragment sequencing. The inference is made that the microbial community of Lake Baikal contains not only the known species but also new, possibly endemic to the lake, bacterial species.

This study was aimed to isolate and characterize actinomycetes having antagonist activity to Dickeya sp., the pathogen of pineapple soft rot. Soil samples were collected from four different pineapple plantation in Lampung. Samples were... more

This study was aimed to isolate and characterize actinomycetes having antagonist activity to Dickeya sp., the pathogen of pineapple soft rot. Soil samples were collected from four different pineapple plantation in Lampung. Samples were air-dried, serially diluted, and plated on actinomycetes isolation agar media; and potential colonies were selected and purified in malt agar medium. Isolates were grouped in different color series based on their aerial-mycelia color, and then morphologically characterized. Antagonist activity of the actinomycetes isolates on Dickeya sp. were evaluated using the same medium. From totally 51 actinomycetes isolates, only 34 isolates that grew well, then screened and tested for antagonistic activity. There were 35 tested isolates (including the control) exhibited a clear zone around the colonies indicating antagonistic activity; only 14 isolates showed clear zone higher than that of the positive control (chloramphenicol). From the smallholder pineapple p...

The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty... more

The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between floc-forming microorganisms and M. parvicella for long-chain fatty acids uptake under aerobic, anoxic, and anaerobic conditions was formulated. According to this hypothesis, M. parvicella exhibits similar long-chain fatty acids uptake capacity with floc-forming microorganisms even at relatively high floc loading values that are very often imposed at selector tanks. Following this hypothesis, the failure of selector tanks to provide for an effective M. parvicella control is evidenced. Based on the experimental results, the ability of M. parvicella to utilize long-chain fatty acids with rates comparable to those of floc formers, even in anoxic...

High G + C gram positive bacteria are in the phylum Actinobacteria. Many bacteria in this phylum are highly pleomorphic in their morphology; the genera ( examples : Corynebacterium and Gardnerella ) several genera such as Streptomyces... more

High G + C gram positive bacteria are in the phylum Actinobacteria. Many bacteria in this phylum are highly pleomorphic in their morphology; the genera ( examples : Corynebacterium and Gardnerella ) several genera such as Streptomyces grow only as extended, often branching filaments. Several important pathogenic genera are found in the Actinobacteria, such as the Mycobacterium species causing tuberculosis is and leprosy.

Dieback caused by the fungus Lasiodiplodia theobromae is an important disease on mango plantations in the United Arab Emirates (UAE). In this study, 53 actinobacterial isolates were obtained from mango rhizosphere soil in the UAE, of... more

Dieback caused by the fungus Lasiodiplodia theobromae is an important disease on mango plantations in the United Arab Emirates (UAE). In this study, 53 actinobacterial isolates were obtained from mango rhizosphere soil in the UAE, of which 35 (66%) were classified as streptomycetes (SA) and 18 (34%) as non-streptomycetes (NSA). Among these isolates, 19 (12 SA and 7 NSA) showed antagonistic activities against L. theobromae associated with either the production of diffusible antifungal metabolites, extracellular cell-wall-degrading enzymes (CWDEs), or both. Using a " novel " mango fruit bioassay, all isolates were screened in vivo for their abilities to reduce lesion severity on fruits inoculated with L. theobromae. Three isolates, two belonging to Streptomyces and one to Micromonospora spp., showed the strongest inhibitory effect against this pathogen in vitro and were therefore selected for tests on mango seedlings. Our results revealed that the antifungal action of S. samsunensis UAE1 was related to antibiosis, and the production of CWDEs (i.e., chitinase) and siderophores; whilst S. cavourensis UAE1 and M. tulbaghiae UAE1 were considered to be associated with antibiotic-and CWDE-production, respectively. Pre-inoculation in greenhouse experiments with the most promising actinobacterial isolates resulted in very high levels of disease protection in mango seedlings subsequently inoculated with the pathogen. This was evident by the dramatic reduction in the estimated disease severity indices of the mango dieback of individual biocontrol agent (BCA) applications compared with the pathogen alone, confirming their potential in the management of mango dieback disease. L. theobromae-infected mango seedlings treated with S. samsunensis showed significantly reduced number of defoliated leaves and conidia counts of L. theobromae by 2-and 4-fold, respectively, in comparison to the other two BCA applications. This indicates that the synergistic antifungal effects of S. samsunensis using multiple modes of action retarded the in planta invasion of L. theobromae. This is the first report of BCA effects against L. theobromae on mango seedlings by microbial antagonists. It is also the first report of actinobacteria naturally existing in the soils of the UAE or elsewhere that show the ability to suppress the mango dieback disease.

Marine actinobacteria isolated from Bay of Bengal and evaluated for the l-asparaginase production capability. A total of 75 actinobacterial strains were isolated and screened for antibacterial activity. Among them, 10 actinobacterial... more

Marine actinobacteria isolated from Bay of Bengal and evaluated for the l-asparaginase production capability. A total of 75 actinobacterial strains were isolated and screened for antibacterial activity. Among them, 10 actinobacterial strains showed significant antibacterial activity. Those strains were identified based on phenotypic and chemotaxonomic characteristics and screened for l-asparaginase production. During screening process, Streptomyces sp. (SS7) showed large pink colored zone (10 mm) around the colony. The strain was further studied for production and characterization of l-asparaginase enzyme. The preferable culture conditions for l-asparaginase were pH 8.5, temperature 40°C, maltose (22 IU) and soya bean meal (25.7 IU) as best carbon and nitrogen sources, respectively. Different substrates were used to optimize the l-asparaginase production. Among them, mangrove leaf extract-I showed maximum yield of 14.5 IU, the enzyme showed 18 fold during sephadex G-100 column purification. These results show that the great potential of Streptomyces sp. (SS7) for the production of l-asparaginase from cheaper source could lead to economic feasibility. The l-asparaginase from Streptomyces sp. (SS7) may be a new active source for natural anticancer agent with potential significance for therapeutic applications.

Endophytic actinomycetes from Azadirachta indica A. Juss. were screened and evaluated for their anti-microbial activity against an array of pathogenic fungi and bacteria. A total of 55 separate isolates were obtained from 20 plants, and... more

Endophytic actinomycetes from Azadirachta indica A. Juss. were screened and evaluated for their anti-microbial activity against an array of pathogenic fungi and bacteria. A total of 55 separate isolates were obtained from 20 plants, and 60% of these showed inhibitory activity against one or more pathogenic fungi and bacteria. Actinomycetes were most commonly recovered from roots (54.5% of all isolates), followed by stems (23.6%), and leaves (21.8%). The dominant genus was Streptomyces (49.09% of all isolates), while Streptosporangium (14.5%), Microbispora (10.9%), Streptoverticillium (5.5%), Sacchromonospora sp. (5.5%), and Nocardia (3.6%) were also recovered. Streptomyces isolates AzR 006, 011, and 031 (all from roots) had acute activity against Pseudomonas fluorescens, while AzR027, 032, and 051 (also all from roots) showed activity against Escherichia coli. Meanwhile, an isolate of Nocardia sp. from leaves (AzL025) showed antagonism against Bacillus subtilis. Overall, 32 of the 55 were found to have broad spectrum significant antimicrobial activity, while about 4% of them showed strong and acute inhibition to pathogenic fungi and bacteria. Isolates of Streptomyces AzR031, 008, and 047, Nocardia sp. AzL025, and Streptosporangium sp. AzR 021 and 048 are of particular interest because they showed significant antagonistic activity against root pathogens, including Pythium and Phytophthora sp. Thus, many of the isolates recovered from A. indica in this study may be used in developing potential bio-control agents against a range of pathogenic fungi and bacteria and in the production of novel natural antimicrobial compounds. These results not only further our understanding of plant–microbe interactions but also indicate that there is an untapped resource of endophytic microorganisms that could be exploited in the biotechnological, medicinal, and agricultural industries.

Thirty-five actinobacterial isolates obtained from Salicornia bigelovii rhizosphere in the United Arab Emirates were evaluated for their potential to produce polyamines and for their abilities to be rhizosphere-competent. The highly... more

Thirty-five actinobacterial isolates obtained from Salicornia bigelovii rhizosphere in the United Arab Emirates were evaluated for their potential to produce polyamines and for their abilities to be rhizosphere-competent. The highly polyamine-producing Actinoplanes deccanensis UAE1 and Streptomyces euryhalinus UAE1 were selected, and their inoculation impacts on S. bigelovii were assessed under greenhouse conditions. Application of any of the two isolates significantly increased the length and dry weight of shoot and root tissues, photosynthetic pigments, and seed yields compared to control plants, suggesting that A. deccanensis and S. euryhalinus can promote S. bigelovii growth. The application of these isolates resulted in significant increases in the levels of endogenous free polyamines and plant growth regulators (auxins, gibberellic acid, and cytokinins), but a concomitant reduction in abscisic acid in S. bigelovii-tested tissues. Specifically, we found that putrescine, spermidine, and spermine produced by S. euryhalinus were the major contributors to plant growth parameters, but to a lesser extent by A. deccanensis. Both A. deccanensis and S. euryhalinus were, however, not capable of producing significant levels of other plant growth regulators in vitro. Plant yield was higher in the presence of S. euryhalinus than with A. deccanensis, suggesting relative superiority of S. euryhalinus as a rhizosphere-competent isolate compared to the nonrhizosphere-competent isolate A. deccanensis. This is the first study reporting the production of polyamines by marine actinobacteria and demonstrating the potential of polyamine-producing actinobacteria to enhance growth of halophytic plants through the increase in the endogenous levels of free polyamines and other plant growth regulators.

Actinobacteria exclusively within the sub-class Acidimicrobidae were shown by 16S rDNA community analysis to be major components of the bacterial community associated with two sponge species in the genus Xestospongia. Four groups of... more

Actinobacteria exclusively within the sub-class Acidimicrobidae were shown by 16S rDNA community analysis to be major components of the bacterial community associated with two sponge species in the genus Xestospongia. Four groups of Actinobacteria were identified in Xestospongia spp., with three of these four groups being found in both Xestospongia muta from Key Largo, Florida and Xestospongia testudinaria from Manado, Indonesia. This suggests that these groups are true symbionts in these sponges and may play a common role in both the Pacific and Atlantic sponge species. The fourth group was found only in X. testudinaria and was a novel assemblage distantly related to any previously sequenced actinobacterial clones. The only actinobacteria that were obtained in initial culturing attempts were Gordonia, Micrococcus and Brachybacterium spp., none of which were represented in the clone libraries. The closest cultured actinobacteria to all the Acidimicrobidae clones from Xestospongia spp. are ‘Microthrix parvicella’ and Acidimicrobium spp. Xestospongia spp. can now be targeted as source material from which to culture novel Acidimicrobidae to investigate their potential as producers of bioactive compounds. Isolation of sponge-associated Acidimicrobidae will also make it possible to elucidate their role as sponge symbionts.

Alois Alzheimer might have mentioned plaques and tangles in a single short paper on pre-senile dementia in 1907 but it was the co-discover of Alzheimer's disease, Oskar Fischer, who in that same year far more extensively reported neuritic... more

Alois Alzheimer might have mentioned plaques and tangles in a single short paper on pre-senile dementia in 1907 but it was the co-discover of Alzheimer's disease, Oskar Fischer, who in that same year far more extensively reported neuritic plaque in 12 cases of senile dementia, a condition which he and many others refused to differentiate from Alzheimer's " pre-senile " dementia. Fischer, Al-zheimer's great rival, speculated that for the most part these plaques, found only in senile demented patients, caused their dementia. Moreover, Fischer felt such cerebral plaque to be the result of an infection and was very specific as to the sort of infection that might be involved. He felt that he had spotted, throughout his Alzheimer's brain autopsies, a tubercular-like Actinobacteria then called Streptothrix (Actinomycosis), often and repeatedly confused with the filamentous cell-wall-deficient (CWD) forms of the tubercular bacilli. At this point for Fischer, this was the possible infectious cause of Alzheimer's. To be sure, Oskar Fischer was the first on record to suggest that chronic infection might be causative for what we today call Alzheimer's disease. Fischer's infectious view never gained immediate popularity, although today, more than a century later, a volume of data supporting such an approach has begun to accumulate. But was Fischer's specific microbe on the right track to discovering the cause of Alzheimer's to begin with? Documents uncovered since then seem to suggest that he was considerably closer than anyone else –either then or since.

To isolate novel actinomycetes and to evaluate their antibacterial activity. Three soil samples were collected from Vengodu (village) in Kanchipuram district, Tamil Nadu, India. Actinomycetes were isolated using serial dilution and... more

To isolate novel actinomycetes and to evaluate their antibacterial activity. Three soil samples were collected from Vengodu (village) in Kanchipuram district, Tamil Nadu, India. Actinomycetes were isolated using serial dilution and plating method on actinomycetes isolation agar. Totally 35 isolates were obtained on the basis of colony characteristics on actinomycetes isolation agar. All the isolates were screened for antibacterial activity by cross streak method. Medium and optimization of day were done for the potent strains using Nathan's agar well diffusion method. Isolation of bioactive compounds from significant active isolates was done by using different media. The most active isolate VAS 10 was identified as Actinobacterium Loyola PBT VAS 10 (accession No. JF501398) using 16s rRNA sequence method. The hexane, ethyl acetate, dichloromethane and butanol extracts of VAS 10 were tested against bacteria. The maximum antibacterial activity was observed in dichloromethane and et...

Intestinal microbiota is composed by a community of microorganisms, which regulate intestinal functions and affect the global health. It is presumable that the well-known intestinal damages induced by Non Steroidal Antiinflammatory Drugs... more

Intestinal microbiota is composed by a community of microorganisms, which regulate intestinal functions and affect the global health. It is presumable that the well-known intestinal damages induced by Non Steroidal Antiinflammatory Drugs (NSAIDs) mirror on the homeostasis of microbiota, as confirmed by studies investigating this aspect. This review reports the evolving knowledge in this field taking into account both intestinal damage and microbiota involvement. In addition, we analyze a recent study reporting how NSAIDs change intestinal bacterial composition and, on this basis, hypothesize further possible interactions. Indeed, NSAIDs are responsible for a marked reduction of Lactobacilli, which act in the maintenance of luminal pH, mucosal permeability, enterocyte adhesion, mucus production, and immune system modulation. Moreover, Bifidobacteria are involved in the modulation of intestinal motility and local immunity and the demonstrated dangerous effect of NSAIDs could operate through an interference with these functions. A participation of microbiota in mesalazine and salycilate prevention of intestinal cancer may be supposed through their ability to stimulate bacterial production of molecules interfering with cell cycle on the basis of scanty available data. Finally, a supplementation with probiotics in chronic users of NSAIDs may help microbiota remodeling in a damaged intestine, but the poor current knowledge does not allow setting a clear indication for their use despite few evidences of a beneficial effect. In conclusion, it is presumable that the multiple effects of NSAIDs on the lower gastro-intestinal tract may involve microbiota alterations and this consideration suggests further investigations.

In assessing the bacterial populations present in spacecraft assembly, spacecraft test, and launch preparation facilities, extremophilic bacteria (requiring severe conditions for growth) and extremotolerant bacteria (tolerant to extreme... more

In assessing the bacterial populations present in spacecraft assembly, spacecraft test, and launch preparation facilities, extremophilic bacteria (requiring severe conditions for growth) and extremotolerant bacteria (tolerant to extreme conditions) were isolated. Several cultivation approaches were employed to select for and identify bacteria that not only survive the nutrient-limiting conditions of clean room environments but can also withstand even more inhospitable environmental stresses. Due to their proximity to spacefaring objects, these bacteria pose a considerable risk for forward contamination of extraterrestrial sites. Samples collected from four geographically distinct National Aeronautics and Space Administration clean rooms were challenged with UV-C irradiation, 5% hydrogen peroxide, heat shock, pH extremes (pH 3.0 and 11.0), temperature extremes (4 degrees C to 65 degrees C), and hypersalinity (25% NaCl) prior to and/or during cultivation as a means of selecting for extremotolerant bacteria. Culture-independent approaches were employed to measure viable microbial (ATP-based) and total bacterial (quantitative PCR-based) burdens. Intracellular ATP concentrations suggested a viable microbial presence ranging from below detection limits to 10(6) cells/m(2). However, only 0.1 to 55% of these viable cells were able to grow on defined culture medium. Isolated members of the Bacillaceae family were more physiologically diverse than those reported in previous studies, including thermophiles (Geobacillus), obligate anaerobes (Paenibacillus), and halotolerant, alkalophilic species (Oceanobacillus and Exiguobacterium). Non-spore-forming microbes (alpha- and beta-proteobacteria and actinobacteria) exhibiting tolerance to the selected stresses were also encountered. The multiassay cultivation approach employed herein enhances the current understanding of the physiological diversity of bacteria housed in these clean rooms and leads us to ponder the origin and means of translocation of thermophiles, anaerobes, and halotolerant alkalophiles into these environments.

A rod-shaped, motile, facultative anaerobic and moderately halotolerant plant growth promoting actinobacterial strain, designated as NCCP-11T, was isolated from paddy grains. To delineate its taxonomic position, the strain was subjected... more

A rod-shaped, motile, facultative anaerobic and moderately halotolerant plant growth promoting actinobacterial strain, designated as NCCP-11T, was isolated from paddy grains. To delineate its taxonomic position, the strain was subjected to polyphasic characterization. Cells of strain NCCP-11T grew at 10-37°;C (optimum 28-32°C), at pH ranges of 6&-9 (optimum growth at pH 7) and in 0-12% (optimum 1-2%) NaCl (w/v) in broth medium. Based on 16S rRNA gene sequence analysis, strain NCCP-11T showed highest similarity to type strains of Cellulomonas hominis (98.99%), and Cellulomonas denverensis (98.09%) and less than 97% with other closely related taxa. The chemotaxonomic data [major menaquinone, MK-9(H4); cell wall peptidoglycan, type A4β; major fatty acids, anteiso-C15:0 (55.7%), C16:0 (15.1%) and C14:0 (12.8%) and anteiso-C17:0 (6.3%); major polar lipids, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol-mannosides and two unknown polar lipids] also supported the affiliation of strain NCCP-11T to genus Cellulomonas. The level of DNA-DNA relatedness between strain NCCP-11T and the two type strains mentioned above was less than 42.7 %. On the basis of DNA-DNA relatedness, physiological and biochemical characteristics and phylogenetic position, strain NCCP-11T can be differentiated from the validly published Cellulomonas species and thus represents as new species, for which the name, Cellulomonas pakistanensis sp. nov. is proposed with the type strain NCCP-11T (= DSM 24792T = JCM 18755T = KCTC 19798T).