Xanthomonas Sp Research Articles

Antimicrobial Activities of Four Strains of <i>Streptomyces sp</i> Isolated from the Pond of the Village of Demba Tiarki Tara in Mali

The search for new molecules is needed to cope with the recrudescence of bacterial resistance. Actinomycetes, especially the genus Streptomyces remains the most requested for the production of bioactive substances. Nineteen samples of soil and mud from the pond of Demba Tiarki Tara were collected and treated. In total, 7 strains of Streptomyces were isolated by the calcium carbonate enrichment technique for the isolation of <i>Streptomyces</i>. The antimicrobial potency of isolated <i>Streptomyces</i> was assessed on human and plants pathogens (<i>Staphylococcus aureus, Aspergillus flavus, Penicillium sp, Xanthomonas sp, Salmonella thyphi, Helminthos sp</i>). Four of the tested actinmycetes strains showed antimicrobial activities against the pathogens used in the in vitro test. But only one strain showed high antagonist activity against <i>Staphylococcus aureus</i> and has a strong ability to produce melanin. Three strains were weakly active on <i>Salmonella typhi</i>. This result showed, for the first time, that the pond of Demba Tiarki Tara (DTT) contains bacteria producing bioactive compounds indicating the medical interest that the local population has in this pond. Secondary metabolite production by one strain may be an effective antibiotic for the management of resistant <i>Staphylococcus aureus</i> strains.

In vitro Antibacterial Activity of Four Essential Oils on Xanthomonas sp., Responsible of the Bacteriosis of the Cashew Tree

Cashew (Anacardium occidentale L.), an important crop in Côte d'Ivoire is prone to many diseases, one of the most redoutable of which is bacteriosis caused by Xanthomonas sp. To limit the use of pesticides in the fight against this bacteriosis, an alternative solution based on the use of essential oils has been evaluated. Antibacterial tests were carried out in vitro with the essential oils of Eucalyptus citriodora, Cymbopogon citratus, Citrus limon, NECO (formulation based on the essential oil of Ocimum gratissimum) and a synthetic pesticide, the callicuivre. The smallest MICs (10 ppm and 60 ppm respectively) were obtained with NECO and the essential oil of Cymbopogon citratus. The highest antibacterial activities were obtained with the essential oil of Cymbopogon citratus and NECO biopesticide. at the dose of 4000 ppm (for inhibition diameters of 20.67mm and 27.33mm respectively). NECO and the essential oil of Cymbopogon citratus could be used as an alternative to the synthetic product in the fight against bacteriosis of cashew.

A comparative study of utilization of single and mixed phenolic compounds by individual and mixed culture.

Three bacterial strains; Pseudomonas sp. TRMK1, Stenotrophomonas sp. TRMK2 and Xanthomonas sp. TRMK3 were isolated from agro-industrial waste by enrichment culture technique that are capable of utilizing phenolic acids as sole source of carbon and energy. These strains were found to utilize p-coumaric, ferulic and caffeic acid. The individual strains utilized 5mM of mixed phenolic acids within 20h of incubation. The bacterial consortium composing these strains was prepared and studied the efficient degradation of phenolic compounds. The bacterial consortium showed the enhanced utilization of 30mM individual and 25mM mixed phenolic acids within 32 and 40h of incubation, respectively. The degradation efficiency of these strains in all the above experiments was above 90%. The prepared bacterial consortium serves as a suitable method for the in situ application of sites contaminated with wide range of phenolic compounds.

Bacterial diseases of wheat caused by Xanthomonas sp. in the Southern Ural: Identification issues

The identification of pathogenic agents isolated from infected wheat seeds and plants, collected in the Southern Ural and characterized by an atypical manifestation of bacterial infection (yellow leaf tips), has been carried out by direct microbiological and molecular methods. In addition, an indirect identification by the hypersensitive reaction (HR) approach has been performed simultaneously with the pathogenicity assessment of isolates using an indicator plant Plectranthus australis R. Br. Isolated samples have been microbiologically identified as Xanthomonas sp. According to the results of the PCR identification with species-specific primers, isolated samples represent Xanthomonas translucens; the reliability of the obtained results is corroborated by the hypersensitive reaction approach used also to assess the pathogenicity of isolates. Winter wheat, especially cv. Pionerskaya 23, where both X. translucens and Pantoea agglomerans were found, suffered more severe symptoms than spring wheat that was only affected by strains of X. translucens. To improve the reliability of the primary diagnostics of a bacterial character of seed infection, the provoking of the pathogen development by temperature or pH stress is proposed.

Purification, Characterization and Antioxidant Activity of Green Seaweed Codium sp

In the present study the Codium sp. polysaccharide was extracted and partially purified in DEAE cellulose. The polysaccharide was estimated for carbohydrate, sulfate content and uronic acid. The elemental analysis of polysaccharides was analyzed for carbon, hydrogen, nitrogen and sulfur. The antibacterial activity of polysaccharide showed maximum 19 mm of inhibition zone against Bacillus cereus and 12 mm of inhibition zone against Xanthomonas sp. Free radical scavenging activity of polysaccharide from Codium sp. was assayed for total antioxidant capacity, reducing power, hydrogen peroxide scavenging activity, DPPH, ABTS, hydroxyl scavenging assay, superoxide anion radical scavenging and nitric oxide. The green seaweed Codium sp. polysaccharide showed rich sources of antibacterial and antioxidant activity.

Biofertilizantes no controle da mancha bacteriana (Xanthomonas spp.) do tomateiro

RESUMO A mancha bacteriana do tomateiro, causada por quatro espécies de Xanthomonas pode provocar perdas significativas na produção da cultura e a utilização de biofertilizantes na proteção de plantas tende a reduzir a incidência de doenças. O objetivo do trabalho foi avaliar o efeito dos biofertilizantes no controle preventivo e curativo da mancha bacteriana do tomateiro. Para o controle preventivo da doença, plantas de tomate cultivar Santa Cruz Kada, com 3 a 4 folhas foram pulverizadas com os biofertilizantes (Soil-Set, Agro-Mos e Cop-R-Quick) e água (testemunha); e dois dias após foram inoculadas por aspersão com a suspensão bacteriana nas concentrações 109 UFC mL-1 (OD550=0,5) e 106UFC mL-1, com o isolado UFU A35 de Xanthomonas sp. Para o controle curativo, as plantas foram inoculadas com a suspensão bacteriana, e dois dias após foram pulverizadas com os biofertilizantes e água. A severidade da mancha bacteriana foi avaliada usando uma escala diagramática; aos 3, 5, 8, 11 e 14 dias após a inoculação e calculada a área abaixo da curva de progresso de doença (AACPD). O controle preventivo foi mais eficiente no manejo da mancha bacteriana do tomateiro, e os diferentes biofertilizantes reduziram a severidade da doença.

Dental Bacterial DNA are Present in the Amniotic Cavity of Healthy Pregnant Women at Term

Aims: To determine if dental bacterial DNA are present in the amniotic cavity of healthy pregnant women undergoing an elective caesarean section at term utilising culture independent techniques. Methods: Pregnant Australian women undergoing an elective caesarean section were recruited. Women completed questionnaires addressing demographics, past and current pregnancies and medical history. One high vaginal swab and three amniotic cavity swabs (amniotic fluid, newborn axilla and placental) were collected under sterile conditions. Samples were analysed using culture-independent techniques to detect the presence of predefined pathogenic bacterial taxa of the oral microbiome. Taxa isolated from the amniotic cavity swabs were compared to those isolated from the vaginal swab. Results: DNA from taxa isolated from the amniotic cavity but not vagina included A. xylosoxidans, A. tumefaciens, B. subtilis, Bartonella sp, Bergeyella sp, C. concisus, C. curvus, C. durum, D. microaerophilus, G. haemolysans, G. morbillorum, G. adiacens, G. elegans, K. pneumoniae, L. casei, L. paracasei, L. fermentum, P. aeruginosa, P. fluorescens, P. pseudoalcaligenes, P. stutzeri, R. microluginosa, S. maltophilia, S. pneumoniae, S. salivarius, S. sanguinis, V. dispar, V. parvula and Xanthomonas sp. Conclusion: The DNA of many pathogenic oral bacteria can be identified in the amniotic cavity of healthy pregnant women at term when utilising culture-independent techniques. Given DNA is not always present in the vagina, the study findings fulfill one criterion necessary for oral haematogenous spread to the amniotic cavity.

Isolation and Characterization of Atrazine-Degrading Xanthomonas sp. ARB2 and Its Use in Bioremediation of Contaminated Soils

Isolation and Characterization of Atrazine-Degrading Xanthomonas sp. ARB2 and Its Use in Bioremediation of Contaminated Soils

Regeneration of inorganic nutrient in eutrophic environment by a bacterium, Xanthomonas sp.

Abstract not availableBangladesh J. Zool. 42(1): 123-127, 2014

Spectrophotometric Screening of Potent Bactericidal Property of Thevetia Peruviana Schum. Leaf and Fruit Rind Extracts on Clinical and Plant Pathogens

The development of multi drug resistance in human and plant pathogens, reconsidering the traditional medicines as antibacterial source and presence of promising phytochemicals in leaf and fruit rind of T. peruviana (S) (Nazneen et al., 2014) prompted the authors to take up the antibacterial evaluation of different extracts. Antibacterial activity, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of various extracts of T. peruviana (S) were measured using methods of National Committee for Clinical Laboratory Standards (NCCLS).The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) spectrophotometric determination of active extracts has found that the MICs of all the active extracts lies between the range of 250 μg to 1250 μg and bactericidal concentration in a range of 500 to 1250 μg. The percentage of inhibition was analysed, where in among all the extracts tested against B. subtilis and E. coli, fruit upper liquid (FUL) exhibited highest inhibition percentage of 33.75% and 30.31 % at 500 μg/ml respectively. Similarly, fruit hexane (FH) extract has the highest inhibition of 15.60% against B. cereus at 750 μg/ml. The Xanthomonas sp. was susceptible to leaf chloroform (LC) with 32.29% of inhibition at 1000 μg/ ml. The activity index and total antimicrobial activity indicates the antibacterial action of extracts.The present investigations have revealed that among the extracts, the fruit rind extracts have most prominent inhibition abilities against tested bacteria, which are validating the use of this plant in traditional system of medicine and this is the first report of exploration of above extracts for their antibacterial activities against B. subtilis, B. cereus, E. coli and Xanthomonas sp. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11206Int J Appl Sci Biotechnol, Vol. 2(4): 451-459

Stepwise bioprocess for exopolysaccharide production using potato starch as carbon source.

Xanthan gum is a biopolymer produced by Xanthomonas sp. XC6. In this study, xanthan gum is produced from potato starch using a stepwise bioprocess design. Potato starch is hydrolyzed using Bacillus sp. having amylase activity and 30.2 g/L reducing sugar was released, while Xanthomonas sp. XC6 can release only 14.5 g/L. Bacillus sp. hydrolyzed potato starch extract was further used as a carbon source for xanthan gum biosynthesis using Xanthomonas sp. XC6. Yeast extract acts as the best nitrogen source, and 10.0 g/L xanthan gum was recovered. Downstreaming process after stepwise bioprocess resulted in 17.4 g/L xanthan gum production, which is 2.8 times higher as compared to single step process.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-014-0273-2) contains supplementary material, which is available to authorized users.

In vitro control of plant pathogenic Xanthomonas spp. using Poncirus trifoliata Rafin.

The secondary metabolites such as essential oil and pure compounds (limonin and imperatorin) from Poncirus trifoliata Rafin were tested for in vitro control of phytopathogenic bacteria of Xanthomonas spp. In vitro studies showed that the oil had inhibitory effect on Xanthomonas campestris pv. compestris KC94-17-XCC, Xanthomonas campestris pv. vesicatoria YK93-4-XCV, Xanthomonas oryzae pv. oryzae KX019-XCO and Xanthomonas sp. SK12 with their inhibition zones and minimum inhibitory concentration (MIC) values ranging from 13.1~22.1 mm and 62.5~125 μg/ml, respectively. Limonin and imperatorin also had in vitro antibacterial potential (MIC: 15.62~62.5 μg/ml) against all the tested Xanthomonas spp. Furthermore, the SEM studies demonstrated that limonin and imperatorin caused morphological changes of Xanthomonas sp. SK12 at the minimum inhibitory concentration (15.62 μg/ml). These results of this study support the possible use of essential oil and natural compounds from P. Trifoliata in agriculture and agro-industries to control plant pathogenic microorganisms.

가금폐기물 처리를 위한 세균유래 케라틴 분해효소의 특성

Keratin wastes are generated in excess of million tons per year worldwide and biodegradation of keratin by microorganisms possessing keratinase activity can be used as an alternative tool to prevent environmental pollution. For practical use of keratinase, its physicochemical properties should be investigated in detail. In this study, we investigated characteristics of keratinase produced by Xanthomonas sp. P5 which is isolated from rhizospheric soil of soybean. The level of keratinase produced by the strain P5 increased with time and reached its maximum (10.6 U/ml) at 3 days. The production of soluble protein had the same tendency as the production of keratinase. Optimal temperature and pH of keratinase were 40℃-45℃ and pH 9, respectively. The enzyme showed broad temperature and pH stabilities. Thermostability profile showed that the enzyme retained 94.6%-100% of the original activity after 1 h treatment at 10℃-40℃. After treatment for 1 h at pH 6-10, 89.2%-100% of the activity was remained. At pH 11, 71.6% of the original activity was retained after 1 h treatment. Although the strain P5 did not degrade human hair, it degraded duck feather and chicken feather. These results indicate that keratinase from Xanthomonas sp. P5 could be not only used to upgrade the nutritional value of feather hydrolysate but also useful in situ biodegradation of feather.

Pseudomonas aeruginosa produces secondary metabolites that have biological activity against plant pathogenic Xanthomonas species

The bioactivity of compounds produced by Pseudomonas aeruginosa (LN strain), against three Xanthomonas species was investigated under greenhouse conditions and using electron microscopy. Chromatographic fractions EAP, VLC3, VLC4, VLC3d and VLC4f were tested against Xanthomonas axonopodis pv. malvacearum, X. axonopodis pv. phaseoli and X. axonopodis pv. citri by disc diffusion. Fractions with antibiotic activity were tested in vivo under greenhouse conditions and their bioactivity was evaluated. Scanning electron microscopy showed that VLC4f affects biofilm formation while VLC4f and VLC3d both affect cell morphology. The semi-purified fractions controlled bacterial diseases caused by Xanthomonas spp. when sprayed on plants under greenhouse conditions. The VLC4f fraction showed superior results in disease management, reducing the number of lesions on cotton and orange leaves by 94%, and reducing disease severity in bean leaves by 73%. The data suggest that the fractions were effective and have potential as an alternative to conventional bactericides in the control of plant diseases caused by Xanthomonas sp under greenhouse conditions.

First Thermostable Endo-β-1,4-Glucanase from Newly Isolated Xanthomonas sp. EC102

A novel gene encoding thermostable endoglucanase was identified in Xanthomonas sp. EC102 from soil. The gene had 1,458 base pairs of open reading frame, which encode a 52-kDa protein of 486 amino acid residues. Sequence of the amino acid residues was similar with the endoglucanase from Xanthomonas campestris pv. campestris ATCC33913 (GenBank Accession No. NP_638867.1) (94 % identity). The endoglucanase was overexpressed in Escherichia coli BL21 and purified. Temperature for the highest enzymatic activity was 70 °C and pH optima was pH 5.5. The specific activity of the endoglucanase toward carboxymethylcellulose (CMC) was approximately 2 μmol min⁻¹ mg⁻¹, V max for CMC was 1.44 μmol mg⁻¹ min⁻¹, and K m values was 25.6 mg mL⁻¹. The EC102 endoglucanase was stable at temperatures up to 60 °C, and it was activated by 0.1 mM of Mn²⁺ and Co²⁺. This is the first report about thermostable endoglucanase from Xanthomonas sp.

In Silico Mining of Simple Sequence Repeats in Whole Genome of Xanthomonas sp.

In current scenario, microsatellites are a large source of genetic markers. In this study, we mined simple sequence repeats in whole genome of Xanthomonas species (Xanthomonas axonopodis pv. citri, Xanthomonas oryzae pv. oryzae, Xanthomonas campestris pv. Campestris) by in silico methods. A total of 640 SSRs, 377 SSRs and 541 SSRs were detected in whole genome having density of 1SSR/8.08 kb, 1SSR/13.10 kb and 1SSR/9.510 kb for 5175.554 kb, 4941.439 kb and 5148.708 kb sequences length respectively. The results elucidated, only 32 types (0.618%), 39 types (0.789%) and 96 types (1.864%) of SSR sequences were present in Xanthomonas axonopodis pv. citri, Xanthomonas oryzae pv.oryzae and Xanthomonas campestris pv. campestis respectively. Depending on the repeat units, the length of SSRs ranged from 10 to 18 bp for di-, 12 to 27 bp for tri-, 12 to 24 bp for tetra-, 20 to 35 bp for penta-, 24 to 72 for hexa-, 21 to 133 bp for hepta-, 24 to 40 bp for octa- and 27 to 36 bp for nano nucleotide repeats. Di-nucleotide repeats were the most frequent repeat type (70.97%) followed by tri-nucleotide (22.23%), hepta–nucleotide (2.86%), hexa-nucleotide (1.91%) and tetra-nucleotide (1.392%) in all three species of Xanthomonas. Annotation of sequences containing SSRs were also carried out to assign function to each of the sequences. SSR containing sequences of Xanthomonas species could not assign any specific class of protein (77.56%) due to the absence of homologs in the protein sequence database and these could be treated as an ideal molecular marker.

The influence of bioaugmentation and biosurfactant addition on bioremediation efficiency of diesel-oil contaminated soil: Feasibility during field studies

The study focused on assessing the influence of bioaugmentation and addition of rhamnolipids on diesel oil biodegradation efficiency during field studies. Initial laboratory studies (measurement of emitted CO2 and dehydrogenase activity) were carried out in order to select the consortium for bioaugmentation as well as to evaluate the most appropriate concentration of rhamnolipids. The selected consortium consisted of following bacterial taxa: Aeromonas hydrophila, Alcaligenes xylosoxidans, Gordonia sp., Pseudomonas fluorescens, Pseudomonas putida, Rhodococcus equi, Stenotrophomonas maltophilia, Xanthomonas sp. It was established that the application of rhamnolipids at 150 mg/kg of soil was most appropriate in terms of dehydrogenase activity. Based on the obtained results, four treatment methods were designed and tested during 365 days of field studies: I) natural attenuation; II) addition of rhamnolipids; III) bioaugmentation; IV) bioaugmentation and addition of rhamnolipids. It was observed that bioaugmentation contributed to the highest diesel oil biodegradation efficiency, whereas the addition of rhamnolipids did not notably influence the treatment process.

Bahasa Indonesia

Nursery disease frequently found on Acacia crassicarpa seedlings is bacterial leaf blight caused by Xanthomonas sp. Disease symptom starts as a small fleck on the leaf which may then develop to leaf strike or leaf blight if the environmental factors are conducive to disease development. Actinomycetes are soil microorganisms that produce biologically active substances such as enzymes and antibiotics. These compounds could inhibit growth of other microorganisms, particularly bacteria. Thus, Actinomycetes are considered as potential candidates of biocontrol agents for plant pathogens. In the current study Actinomycetes isolated from a wide range of localities were screened for their efficacy against Xanthomonas sp. in vitro. The objective of this study was to obtain Actinomycete isolates effective against Xanthomonas, to mitigate impact of the pathogen on quality of A. crassicarpa seedlings. All Actinomycete collections were isolated from soil by a chain of enrichment isolation procedures. The antibiotic activities were investigated through antimicrobial screening tests using paper discs on assay plates. Of the 75 Actinomycete isolates originally collected and screened, 5 isolates showed good antimicrobial activities against Xanthomonas and are therefore considered as potential biocontrol agent candidates.

First Report in Hawai'i of Xanthomonas citri pv. mangiferaeindicae Causing Bacterial Black Spot on Mangifera indica.

Bacterial black spot of mango (Mangifera indica) caused by Xanthomonas citri pv. mangiferaeindicae (Xcm), is an economically important disease in tropical and subtropical areas (3). Xcm can infect a wide range of mango cultivars and induces raised, angular, black leaf lesions, sometimes with a chlorotic halo. Fruit symptoms appear as small, water-soaked spots on the lenticels that become star-shaped, erumpent, and exude an infectious gum (3). The bacterium can also cause latent infections (2). Immature mango fruit with black spots on the epidermis were collected in August 2012 from mango trees of the cvs. Raposa and Pirie at a residence in Pukalani, Hawai'i, on the island of Maui. Similar symptoms were seen on a tree of the mango cv. Common (also known as 'Spanish' or 'Lahaina') at a nearby golf course. Mango fruit with black lesions, and leaves showing black lesions with yellow halos, were collected in August 2012 from mango trees of the cv. Haden at a residence in Kaimuki, Hawai'i, on the island of O'ahu. Xanthomonas-like bacterial colonies were isolated on TZC agar. Suspect colonies were non-pigmented on YDC agar. A fruit strain of the bacterium from Maui (A6081A) and a strain from each of a fruit (A6081B) and a leaf (A6082) from O'ahu were each gram-negative, oxidative, positive for both starch and esculin hydrolysis, and negative for nitrate reduction, resulting in presumptive identification as a Xanthomonas sp. The three strains were further characterized by Microlog (Biolog, Inc. Hayward, CA), which showed the closest match with X. campestris. In addition, 16S rDNA PCR assays showed the closest match (99% similarity) with X. citri strains, and RIF marker analysis of dnaA (4) grouped the three strains with Xcm strain LMG 941 (Accession No. CAHO01000002.1). Hypersensitivity responses typical of xanthomonads were observed when these strains were infiltrated into tobacco leaves, whereas no response was observed using sterile water. Leaves of 3-week-old mango seedlings were infiltrated using 10 μl (~108 CFU/ml) of each strain suspended in sterilized water (six to eight inoculations per leaf, four leaves per plant, and three replicate plants per strain). The negative control treatments consisted of inoculation with sterile water, as well as an incompatible pathogen, X. hortorum pv. vitians (A6076), isolated from lettuce. Typical symptoms of bacterial black spot were observed for all strains assayed approximately 2 weeks after inoculation. No lesions were observed on the negative control plants. Koch's postulates were satisfied following reisolation and identification of the Xanthomonas strains from the infected plant tissues, using the biochemical and PCR methods described above. Results for strains from the two islands confirmed published descriptions of the pathogen, indicating that the pathogen causing symptoms on these mango trees is Xcm (1). Cultures and infected plant samples were sent to USDA APHIS and CPHST NPGLB facilities where this identification was confirmed. To our knowledge, this is the first report of bacterial black spot of mango in Hawai'i or anywhere in the United States. It is unknown whether this disease is a new occurrence or has not been reported previously. The origin of the primary inoculum is unknown.

Growth inhibitory potential of polyene type metabolite producing Streptomyces speibonae ERI-01

A Gram positive, filamentous, spore forming antagonistic Streptomyces speibonae ERI-01derived from Western Ghats of Tamil Nadu, India, was studied for its antagonistic activities. Preliminary screening revealed that 38% of Streptomyces strains showed activity against Bacillus subtilis (34%), Staphylococcus aureus (32.4%), Staphylococcus epidermidis (27%), Escherichia coli (27%) Enterococcus faecalis (25%), Pseudomonas aeruginosa (22%) (Klebsiella pneumonia) and 18% (Xanthomonas sp), respectively. However, Streptomyces sp. ERI-01 exhibited significant antimicrobial activity against all the tested bacteria compared to other Streptomyces strains. The 16S rDNA gene based phylogenetic affiliation was determined by using bioinformatic tools identifiedStreptomyces sp. ERI-01 with 99% sequence similarity to Streptomyces speibonae.Fermentation conditions for antibacterial compound production were optimized. The antibacterial substances were extracted using chloroform, ethyl acetate and methanolfrom modified nutrient glucose medium (MNGA) in which ERI-01 had grown for 8 days at 28°C. Antimicrobial activity was assessed using the broth microdilution technique. The lowest minimum inhibitory concentration (MIC) of crude extracts and column purifiedfractions of ERI-01 against Gram positive and Gram negative bacterial pathogens were determined. The lowest MIC of the extract for B. subtilis, S. aureus, S. epidermidis and P. aeruginosa were 0.25 mg/ml. respectively. Extracts were evaluated for their typical polyene-like property. Key words: Streptomyces, Antibacterial activity, minimum inhibitory concentration (MIC), polyene.