Arthrobacter Spp Research Articles

REMEDIATION POTENTIALS OF WHEAT-BRAN AND WOOD-CHIPS ON EFFLUENT CONTAMINATED SOILS FROM PAINT INDUSTRIES IN ABA, ABIA STATE NIGERIA

The remediation potentials of wheat bran and wood chips as Bulking-agents on paint effluent-Polluted Soils was evaluated. Different concentrations of bulking agents (10%, 30%, and 50%) were introduced into soils polluted with effluents and the physicochemical and microbiological properties of the soils were monitored for a period of 24 weeks. The Mean Heterotrophic Count (THC) of the Bacterial and fungal Isolates from the Paint effluents indicates that the effluents from sample F showed the highest bacterial count of 6.66±2.51 x 104cfu/ml, while sample B exhibited the least bacterial counts of 1.7±2.00x104 cfu/ml. Sample B showed the highest fungal count of 7.5±0.21 x104 cfu/ml while sample E showed the least count of 5.7±12.10x104 cfu/ml. The microorganisms isolated from the paint industry effluents include species of Staphylococcus, Klebsiella, Bacillus, Rhizobium, Pseudomonas, Salmonella, Mucor, Aspergillus niger, Fusarium, Aspergillus niger, Penicillium funiculosum and Geotrichum. Bacterial and fungal counts shows wood chips contain of 3.20x104cfu/g and 1.58x104cfu/g respectively while Wheat bran contains 3.47x104cfu/g and 1.77x104cfu/grespectively. Fungal isolates from the bulking agents include Saccharomyces cerevisiae, Rhodotorula species, Rhizopus species, Aspergillus niger, Aspergillus flavus and Penicillum notatum. The Bacterial and fungal counts of the paint-effluent polluted soil mixed with bulking agents over a 6-month remediation period increased progressively from the 1st week to the week 8, after which there was a decline from week 9 down. The polluted soil without amendment presented a slight increase in microbial growth. Higher microbial growth rates were manifested by the 50% amended option, followed by 30%, 10% and then the control. The Total Heterotrophic Bacteria isolated from the polluted soil amended with bulking agents include Pseudomonas putida, Serratia spp., Flavobacterium spp., Micrococcus spp., Bacillus spp., Klebsiella spp. and Arthrobacter spp. The Mean Physicochemical properties of the paint-effluent polluted soil mixed with bulking agents over the 24 weeks remediation reveals the pH ranges from 6.60±0.10 to 7.54±0.09 for the paint effluent polluted soil amended with a combination of the bulking agents. The concentrations of zinc, total nitrogen, total organic carbon and electrical conductivity levels had significant statistical difference across the samples through the period of remediation at p< 0.05. Germination test reveals growth of the bean seeds (Vicia faba) after 6 days of planting but significantly in the 50% treatment samples. The study however, demonstrates that paint effluent polluted soils treated with combination of bulking agents mainly at 50% amendment concentration reduces the toxicity of pollutants and increase the percentage of germination.

Bacteria isolated from Triticum monococcum ssp. monococcum roots can improve wheat hologenome in agriculture.

Triticum monococcum ssp. monococcum is an ancestral wheat species originated from Karacadağ Mountain of Turkey more than ten thousand years ago. Because of environmental and anthropogenic effects, food supply and demand are not balanced. Agricultural activities such as breeding, and fertilization are important to sustain the balance. Conventional breeding and fertilization applications usually neglect contribution of plant related hologenomes in agricultural yield. The disruption of plant growth promoting microorganisms results in intensive usage of chemical fertilizers. The harmony between plant and plant-associated microorganisms is important for sustainability. In this study, isolation, biochemical characterization, and impact on plant growth parameters of natural bacteria associated with Triticum monococcum ssp. monococcum hologenome were aimed. The collection of root samples and isolations of the root-associated bacterial species were carried out from local wheat lands. According to interpretation of three identification methods (MALDI-TOF, 16S rDNA, 16S-23S rDNA) eight isolates are Arthrobacter spp. ESU164, Arthrobacter spp. ESU193, Pseudomonas spp. ESU131, Pseudomonas spp. ESU141, Pseudomonas poae strain ESU182, Pseudomonas thivervalensis strain ESU192, Pseudomonas spp. ESU1531, Bacillus subtilis strain ESU181. For each isolate we investigated biochemical properties especially nitrogen fixation, phosphate solubilization, and indole-3-acetic acid production abilities. The results show that all isolates are nitrogen fixers and the best phosphate solubilizer have been reported as Pseudomonas spp. ESU131 with 2.805 ± 0.439. All isolates are indole-3-acetic acid productors. 2 isolates affected the coleoptile lengths, 7 bacterial isolates showed statistically positive effect on root number, and 5 isolates promote the root lengths and the root fresh weights.

Antibiotic resistance and cold-adaptive enzymes of antarctic culturable bacteria from King George Island

Cryotolerance in microorganisms from polar regions provides their survival through alternating freezing and thawing cycles. Our research was aimed at biodiversity analysis of culturable bacteria from the King George Island near Antarctica including their antibiotic resistance and cold-adaptive enzymes. Average bacterial density was estimated as 3 × 106 cells/mL but the number of colony-forming units (CFU) was essentially lower - (3.2–9.2)x103 cells/mL. Totally, 83 stable strains were isolated and identified using phylogenetic analysis of 16S rRNA gene nucleotide sequences and phenotypic traits. Main groups were the Gram-negative Pseudomonas and Duganella species as well as Gram-positive Arthrobacter spp. Besides, eubacteria Psychrobacter, Flavobacterium, Clavibacter, Aquaspirillum, Polaromonas, Actinibacterium, Shewanella, Kocuria and families Comamonadacea, Actinobacteridae were found. Genetic diversity of the bacteria was elevated with plasmids of different lengths in 33 strains but no correlation between the plasmids content and antibiotic resistance was found. Among cold-adapted enzymes antioxidant catalases (91.5%), peroxidases (57.5%), alkaline phosphatases (42.2%) prevailed; unspecific exonucleases were revealed in 16.9% strains and restriction endonucleases of type II - in 8.4% strains only. Lypases were detected in 24 strains (28.9%) and could facilitate membrane fluidity at low temperatures. Despite the antibiotic resistance the Antarctic cultivable eubacteria are mainly not pathogenic and may serve as sources of plasmids and cold-adapted enzymes for biotechnology.

Biological and chemical characterization of antimicrobial activity in Arthrobacter spp. isolated from disease-suppressive compost.

Antagonistic bacteria can act as biocontrol agents against various phytopathogens. Recently, Arthrobacter spp. demonstrated antifungal activity, but were not further characterized. In this study, the antimicrobial activity of Arthrobacter humicola strains M9-1A, M9-2, and M9-8, and Arthrobacter psychrophenolicus strain M9-17 were evaluated against nine plant pathogens in vitro, and their cell-free filtrates were additionally assessed for inhibition of Alternaria alternata and suppression of black mold disease on tomato fruit. Results indicated that A. humicola M9-1A and A. psychrophenolicus M9-17 were the most inhibitory, reducing growth of seven of the pathogens studied. Cell-free filtrates of A. psychrophenolicus M9-17 reduced the growth of most pathogens. All cell-free bacterial filtrates, except those from A. humicola M9-2, suppressed black mold on tomato fruit. Disk diffusion assays with ethyl acetate soluble culture filtrate extracts of all bacteria reduced the mycelial growth of A. alternata. Clear inhibition zones were observed for A. psychrophenolicus M9-17 extracts using drop bioassays. The antifungal compound N-acetyltryptamine was purified and characterized from the A. psychrophenolicus M9-17 cell-free ethyl acetate soluble extract. This study suggests that antibiosis may play a key role in the antimicrobial activity of Arthrobacter spp.

ПРОРАСТАНИЕ СЕМЯН ЗЛАКОВ ПОД ВЛИЯНИЕМ КОМПОЗИЦИЙ АЗОТФИКСИРУЮЩИХ И ФОСФАТМОБИЛИЗУЮЩИХ БАКТЕРИЙ ИЗ ПОЧВ, ВОЗДЕЛЫВАЕМЫХ В УСЛОВИЯХ ДАЛЬНЕГО ВОСТОКА

Mineral fertilizers which can significantly increase crop productivity have an adverse effect on the soil and the environment as a whole when used for a long time. Microorganisms, as an alternative to mineral fertilizers, stimulate plant growth and development due to their ability to fix nitrogen, produce siderophores, phytohormones and enzymes, dissolve inaccessible elements of mineral nutrition, suppress plant pathogens, and increase consumption of water and nutrients. However, the effectiveness of such preparations highly depends on factors of a new environment. We believe that bacteria from soils that have long been exposed to various agricultural practices may be good plant stimulants. In the presented study, for the first time, we have isolated local active strains of nitrogen-fixing and phosphate-mobilizing bacteria from soils subjected to 74-year stationary intensive farming in the conditions of the Russian Far East and revealed isolates and their combinations which stimulate wheat and barley seed germination and seedling growth. The aim of the work was to study the plant-stimulating properties of nitrogen-fixing and phosphate-mobilizing bacteria from soils that have been actively exposed to mineral fertilizers for a long time. Bacteria were isolated from soils sampled in October 2015 (the experimental field 8, Federal Research Center for Agrobiotechnology FEB RAS, Ussuriysk, Primorsky Territory, Russia). The seeds of wheat Triticum aestivum L. cultivar Primorskaya 50, and barley Hordeum vurlage L. cultivar Tikhookeanskii (collection of the Federal Research Center for Agrobiotechnology FEB RAS) were treated. Of 68 bacterial isolates with different cultural and morphological properties, three isolates, the Acinetobacter spp. N1, Azotobacter spp. N2, and Clostridium spp. N3 were nitrogen fixers, and four isolates, the Serratia spp. P6, Bacillus spp. P7), Arthrobacter spp. P8, and Pantoea spp. P19 were phosphate-mobilizing bacteria. Tests with the monocultures of nitrogen-fixing and phosphate-mobilizing isolates and their different binary compositions showed a 13-51 % increase (p ≤ 0.05) in wheat seed germination energy and 15-54 % increase (p ≤ 0.05) in barley seed germination energy compared to the untreated control. Laboratory germination of wheat seeds increased by 2-32 %, barley seeds by 7-30 % compared to untreated control. The barley seedlings were 1.8 times longer, and the roots were 2.7 times longer. Th binary combination N2P19, P6P19, and P8P19 caused the highest height of seedlings (120-140 mm, p ≤ 0.05), and with P6P7, N2P19, and P6P19 the roots were the longest (120-130 mm, p ≤ 0.05). These results allow us to conclude that short-term soaking seeds in the suspensions of the tested nitrogen-fixing and phosphate-mobilizing isolates improves seed germination energy and laboratory germination, and increases shoot and root length. Binary bacterial compositions have a greater effect on seed germination than monocultures. The strains N1 (Acinetobacter spp.), N2 (Azotobacter spp.), and P19 (Pantoea spp.) are the best stimulants. Species-specific differences in plant response to the treatment is probably due to lack of genetic, biochemical and physiological complementarities between specific plant species and the bacteria.

EFFECTS OF NITROGEN-FIXING AND PHOSPHATE-SOLUBILIZING MICROORGANISMS FROM THE FAR EAST AGRICULTURAL SOILS ON THE CEREAL SEED GERMINATION

Mineral fertilizers which can significantly increase crop productivity have an adverse effect on the soil and the environment as a whole when used for a long time. Microorganisms, as an alternative to mineral fertilizers, stimulate plant growth and development due to their ability to fix nitrogen, produce siderophores, phytohormones and enzymes, dissolve inaccessible elements of mineral nutrition, suppress plant pathogens, and increase consumption of water and nutrients. However, the effectiveness of such preparations highly depends on factors of a new environment. We believe that bacteria from soils that have long been exposed to various agricultural practices may be good plant stimulants. In the presented study, for the first time, we have isolated local active strains of nitrogen-fixing and phosphate-mobilizing bacteria from soils subjected to 74-year stationary intensive farming in the conditions of the Russian Far East and revealed isolates and their combinations which stimulate wheat and barley seed germination and seedling growth. The aim of the work was to study the plant-stimulating properties of nitrogen-fixing and phosphate-mobilizing bacteria from soils that have been actively exposed to mineral fertilizers for a long time. Bacteria were isolated from soils sampled in October 2015 (the experimental field 8, Federal Research Center for Agrobiotechnology FEB RAS, Ussuriysk, Primorsky Territory, Russia). The seeds of wheat Triticum aestivum L. cultivar Primorskaya 50, and barley Hordeum vurlage L. cultivar Tikhookeanskii (collection of the Federal Research Center for Agrobiotechnology FEB RAS) were treated. Of 68 bacterial isolates with different cultural and morphological properties, three isolates, the Acinetobacter spp. N1, Azotobacter spp. N2, and Clostridium spp. N3 were nitrogen fixers, and four isolates, the Serratia spp. P6, Bacillus spp. P7), Arthrobacter spp. P8, and Pantoea spp. P19 were phosphate-mobilizing bacteria. Tests with the monocultures of nitrogen-fixing and phosphate-mobilizing isolates and their different binary compositions showed a 13-51 % increase (p ≤ 0.05) in wheat seed germination energy and 15-54 % increase (p ≤ 0.05) in barley seed germination energy compared to the untreated control. Laboratory germination of wheat seeds increased by 2-32 %, barley seeds by 7-30 % compared to untreated control. The barley seedlings were 1.8 times longer, and the roots were 2.7 times longer. Th binary combination N2P19, P6P19, and P8P19 caused the highest height of seedlings (120-140 mm, p ≤ 0.05), and with P6P7, N2P19, and P6P19 the roots were the longest (120-130 mm, p ≤ 0.05). These results allow us to conclude that short-term soaking seeds in the suspensions of the tested nitrogen-fixing and phosphate-mobilizing isolates improves seed germination energy and laboratory germination, and increases shoot and root length. Binary bacterial compositions have a greater effect on seed germination than monocultures. The strains N1 (Acinetobacter spp.), N2 (Azotobacter spp.), and P19 (Pantoea spp.) are the best stimulants. Species-specific differences in plant response to the treatment is probably due to lack of genetic, biochemical and physiological complementarities between specific plant species and the bacteria.

Effect of the Simultaneous Action of Zinc and Chromium on Arthrobacter spp.

Bacteria are regarded as the most effective in the detoxification of heavy metals, being environmental compatible. Metalloresistant bacteria are usually found in nature in highly contaminated environment where they interact with a combination of several toxic metals. For the present research, Arthrobacter oxydans and Arthrobacter globiformis have been isolated from the soil samples of the most polluted regions of Georgia, rich with manganese and iron, and contain co-produced toxic metals such as Cr, V, Zn, Ni, Pb, and Mo. We have studied the effects of the metals with different valence/charge on the metalloresistant Arthrobacter spp., the divalent cation—Zn(II) and the hexavalent anion—Cr(VI). The permanent presence of a nontoxic concentration of zinc alone or zinc together with the subtoxic concentration of chromium at the growth of A. oxydans and A. globiformis as batch culture causes the activation of the zinc primary uptake system transporters from the ZIP family (Zrt1). Chromium does not affect the process. The studied Arthrobacter spp. differ by the character of the activation of the antioxidant defense system. Chromium and zinc concomitant action causes the strongest oxidative stress in the case of A. globiformis that is demonstrated by the increased activity of superoxide dismutase (SOD) and catalase. In the case of A. oxydans, the zinc separate action, and the joint action of zinc and chromium decreases the activity of SOD and catalase. The antioxidant system is active in A. globiformis at the prolonged action of metals (96 h), whereas the cells of A. oxyidans activate the other defense mechanisms to survive.

Characterization of agarolytic enzymes of Arthrobacter spp. AG-1 for the whole cell conversion of agar into 3,6-anhydro-α- l -galactose in one pot

Abstract 3,6-anhydro-α- l -galactose ( l -AHG) is a commercially unavailable monosaccharide with high therapeutic value, in particular, anti-viral. l -AHG is a selective inhibitor of HIV reverse transcriptase. Till date, the synthesis of l -AHG remains an intricate process and there is a need for a simpler approach producing l -AHG industrially. Herein, we report an agar-hydrolyzing Arthrobacter spp. AG-1 isolated from Gulf of Mannar, Tamil Nadu which completely converts agar to l -AHG with their extracellular agarase in one pot. The optimal temperature and pH for the maximal activity of Arthrobacter spp. strain AG-1 were 45 °C and pH 7 respectively. We purified and characterized the 44 kDa agarase involved in the glycoside hydrolysis. The Vmax, Km, and Kcat value of the agarase were determined as 1.7848 × 10−2 U/mg, 0.01825 ± 0.001 M and 0.1748 ± 0.006 S−1 respectively. Presence of l -AHG was confirmed by TLC. Detailed ESI–MS revealed the presence of a relatively higher abundance of l -AHG and chemical fingerprinting analysis by FT-IR, GC–MS and CD confirmed that the end product as l -AHG. Additionally, l -AHG exhibited notable anti-inflammatory and antibacterial activity. The whole cell biocatalytic system is predicted as a starting point for a more detailed study on Arthrobacter spp. extracellular agarase.

CYSTIC ENDOMETRIAL HYPERPLASIA AND BACTERIAL ENDOMETRITIS ASSOCIATED WITH AN INTRAUTERINE FOREIGN BODY IN A GUINEA PIG WITH OVARIAN CYSTIC DISEASE

A 3-year-old, 920g intact female guinea pig presented with a 4-month history of nonpruritic hair loss on the ventral abdomen. The physical examination revealed flank and ventral abdominal alopecia, mucoid vulvar discharge, and abdominal distension. Bilateral rounded masses just caudal to the kidneys and structures consistent with enlarged uterine horns were detected on abdominal palpation. Abdominal ultrasound revealed bilateral ovarian cysts, thickened uterine horns, and multiple circular hypoechoic and anechoic structures in the uterine wall. The patient underwent ovariohysterectomy. Gross examination of the uterus revealed a piece of hay in the left uterine horn. A final diagnosis was hormonally active ovarian follicular cysts, cystic endometrial hyperplasia, and purulent bacterial endometritis caused by Escherichia coli, Fusobacterium nucleatum, and Arthrobacter spp. Cystic endometrial hyperplasia is infrequently reported in guinea pigs, and this report describes an associated bacterial endometritis and uterine foreign body with concurrent ovarian cysts.

Evidences for Microbial Precipitation of Calcite in Speleothems from Krem Syndai in Jaintia Hills, Meghalaya, India

ABSTRACTSpeleothems from Krem Syndai, Meghalaya in Northeast India were studied for their microbial diversity using 16S rDNA-based phylogenetic approach and conventional microbiological techniques along with geochemistry, mineralogy and in vitro experiments to understand participation of microorganisms in CaCO3 precipitation. Speleothems imaged by scanning electron microscopy showed round coccoid-like, sporangia-like and spinose calcified structures, numerous broken cocci shells with spotted interiors inside a calcite crystal, honeycomb long reticulate, smooth, flat, twisted, ribbon-like, tubular, beaded, microbe-mineralized filaments and extracellular polymeric substances (EPS). Fourier spectroscopy indicated the presence of various organic compounds. δ13C and δ18O isotopic ratios of speleothems ranged from −4.65 to −7.34‰ and −3.06 to −6.80‰, respectively. Total number of microbial cells using SYBR Gold was high. Fluorescence in situ hybridization (FISH) indicated approximately 3 × 105 to 5 × 105 cells g sed–1 in the speleothems out of which the number of microbes belonging to Eubacteria ranged from 1.8 × 105 to 3.6 × 105 cells, g sed–1. FISH showed ∼45% active microbial cells of the total cell number in samples. DNA-based high-throughput amplicon sequencing revealed 19 bacterial phyla in the speleothem. Approximately 42% of the sequences were similar to Proteobacteria (Alphaproteobacteria: 22.4%, Betaproteobacteria: 8.9%, Gammaproteobacteria: 8.6%). Sequences similar to Nitrospiraceae (22.8%) had the highest proportion of sequences belonging to a single family. Bacterial strains isolated from the speleothems raised alkalinity and precipitated calcite in the laboratory cultures which was confirmed by X-ray diffraction (XRD) analyses. These isolates belonged to Bacillus spp., Actinomycetes spp., Streptomyces spp., Pseudomonas spp., Micrococcus spp., Staphylococcus spp., Xanthobacter spp. and Arthrobacter spp. Overall, the results showed unequivocal evidence of bacterial fingerprints during CaCO3 precipitation in the cave.

Life history correlates of fecal bacterial species richness in a wild population of the blue tit Cyanistes caeruleus.

Very little is known about the normal gastrointestinal flora of wild birds, or how it might affect or reflect the host's life-history traits. The aim of this study was to survey the species richness of bacteria in the feces of a wild population of blue tits Cyanistes caeruleus and to explore the relationships between bacterial species richness and various life-history traits, such as age, sex, and reproductive success. Using PCR-TGGE, 55 operational taxonomic units (OTUs) were identified in blue tit feces. DNA sequencing revealed that the 16S rRNA gene was amplified from a diverse range of bacteria, including those that shared closest homology with Bacillus licheniformis, Campylobacter lari, Pseudomonas spp., and Salmonella spp. For adults, there was a significant negative relationship between bacterial species richness and the likelihood of being detected alive the following breeding season; bacterial richness was consistent across years but declined through the breeding season; and breeding pairs had significantly more similar bacterial richness than expected by chance alone. Reduced adult survival was correlated with the presence of an OTU most closely resembling C. lari; enhanced adult survival was associated with an OTU most similar to Arthrobacter spp. For nestlings, there was no significant change in bacterial species richness between the first and second week after hatching, and nestlings sharing the same nest had significantly more similar bacterial richness. Collectively, these results provide compelling evidence that bacterial species richness was associated with several aspects of the life history of their hosts.

Paratransgenesis feasibility in the honeybee (Apis mellifera) using Fructobacillus fructosus commensal.

To establish the molecular tools for honeybee paratransgenesis. Commensal bacteria were isolated from two honeybees. Based on 16S ribosomal RNA sequence analysis, some isolates were identified as Fructobacillus fructosus, Lactobacillus kunkeei, Gilliamella apicola, Acinetobacter spp, Arthrobacter spp and Pseudomonas spp. Rolling circle and theta replicons were successfully introduced into F.fructosus and Lact.kunkeei. Green fluorescent protein was expressed into both species. The 7·3Kb Lactococcus lactis subsp. cremoris MG1363 operon encoding a cluster of five genes involved in the metabolism of galactose via the Leloir pathway was functionally expressed into a non-galactose-fermenting strain of F.fructosus enabling it to grow on galactose as a sole carbon source. Fructophilic lactic acid bacteria, F.fructosus and Lact.kunkeei, are amenable to extensive genetic manipulations. This is the first study demonstrating the feasibility of genetically engineering honeybee commensals, thus establishing the tools necessary for honeybee paratransgenesis.

Effect of dietary probiotic supplementation on growth and innate immune system in sole (Solea senegalensis Kaup, 1858) subjected to pathogenic bacteria infection and handling stress

Effect of dietary probiotic supplementation on growth and innate immune system in sole (Solea senegalensis Kaup, 1858) subjected to pathogenic bacteria infection and handling stress

Biodegradation of Pre-Treated Low Density Polyethylene Spent Saline Vials by selected Arthrobacter Spp.

Biodegradation of Pre-Treated Low Density Polyethylene Spent Saline Vials by selected Arthrobacter Spp.

An Arthrobacter spp. Bacteremia Leading to Fetal Death and Maternal Disseminated Intravascular Coagulation

A 34-year-old parous woman developed high fever and threatened preterm labor after a 1-day trip, for which she was receiving prenatal care at a hospital. Three days after onset, at 24 4/7 weeks of gestation, she was transferred to our hospital in an emergency. Soon after the woman's arrival at our hospital, the infant was spontaneously stillborn via a transvaginal delivery. Laboratory tests revealed severe maternal disseminated intravascular coagulation with renal and liver insufficiency. Histopathologic examination of the placenta revealed vast fibrin deposition and remarkable neutrophilic infiltration in the intervillous space, suggesting a rare bacterial infection caused by Arthrobacter spp. The bacteria were predominantly detected in the placenta and maternal blood serum by common bacterial 16S rRNA sequencing after polymerase chain reaction amplification. We report the first case, to our knowledge, of bacteremia with Arthrobacter spp., which may lead to maternal disseminated intravascular coagulation and intrauterine fetal death.

The Mutagenecity Effect of Aqueous Extracts of Malva parviflora by Bacterial System (part one)

his study was carried out in order to determine the toxic and mutagenic and antimutagenic effects for Mallow (Malva parviflora) against the mutagenic effect of Methotrexate (MTX).The effect was studied in a bacterial system (G-system). The used system consisted of three isolates G3 Bacillus spp, G12 Arthrobacter spp and G27 Brevibacterium spp. The study depended on recording survival fraction (Sx) as an indicator for the induction of Streptomycin and Refampicin resistance mutants as a genetic marker. Water Extract was prepared from fresh and dry mallow leaves, stems, flowers and roots Gradual concentrations of plant water extracts were use to choose the suitable concentration which is remembered the negative control. The interactions included three types of treatments (pre - MTX, with- MTX and post-MTX) as a chemical mutagen in order to determine the mechanisms of this plant extracts in preventing or reducing the genotoxic effect of MTX. The results showed that the interaction effect between the optimum concentration of water extract and the mutagen on survival fraction (Sx) increase the value of the survival fraction of G-system isolates to reach normal value compare with positive control (MTX ). The results of the interaction between optimum concentration for extracts and the treatment with mutagen to induce resistance mutant for streptomycin and refampicin found that the MTX had no effect to induce resistance mutant for these two antibiotics, for the three types of treatment (pre-MTX, with-MTX, and post- MTX) for all extracts, the water extract suppress or repair mutant and give protection 100% for bacterial cells.

Antagonistic activity of bacteria isolated from crops cultivated in a rotation system and a monoculture against Pythium debaryanum and Fusarium oxysporum

The effect of crop rotation and monocropping on the occurrence of bacteria with antagonistic activity toward Pythium debaryanum and Fusarium oxysporum was shown. Arthrobacter spp., fluorescent Pseudomonas spp. and actinomycetes were isolated from winter rape, sugar beet and winter barley rhizosphere and bulk soil from the plots of a long-term crop rotation experiment (18 years). The occurrence of mycoantagonistic isolates and their antibiosis level exhibited specificity for the site, crop and crop rotation. Mycoantagonistic activity was common among actinomycetes and fluorescent Pseudomonas spp. and less frequent among Arthrobacter spp. Antibiosis of fluorescent Pseudomonas spp. and Arthrobacter spp. was in general stronger against P. debaryanum than F. oxysporum. The highest percentage of antagonistic Pseudomonas spp. against P. debaryanum was in the plots of barley crop, while plots of winter rape showed higher frequency of antagonists against F. oxysporum. The highest antibiosis activity of Arthrobacter spp. against both pathogens occurred in isolates from barley and winter rape monoculture, and there were no F. oxysporum antagonists among these bacteria in sugar beet monoculture. Most of actinomycete isolates strongly inhibited growth of P. debaryanum and F. oxysporum. The percentage of mycoantagonistic actinomycetes and their antibiosis level were the highest in the 6-year crop rotation system.

ANTIMUTAGENIC EFFECT OF CARROT (Daucus carota) ON INDUCTION OF STREPTOMYCIN AND RIFAMPICIN RESISTANT MUTANTS IN BACTERIAL SYSTEMS

G-system was used to study the cytotoxicity and genotoxicity of carrot root juice. The system composed of three bacterial strains: G3 (Bacillus spp), G12 (Arthrobacter spp), G27 (Brevibacterium spp). The strains are Gram positive, sensitive to crystal violet, Streptomycin (10µg / ml) and Rifampicin (20µg / ml) (Chromosomal markers). Effect of carrot root juice at different concentrations 50, 100, 200µl on log culture suspended cells was studied. Cyclophosphamide (Cp) drug (Mutagen) was used at 1, 10, 50, 100 µg/ml. The juice and the mutagen were tested for cytotoxicity by estimating the survival index (Sx), and genotoxicity by estimating the mutant frequency of Streptomycin and Rifampicin resistance. Results showed that low conc (s) (50, 100µl) of carrot juice had no cytotoxic or genotoxic effect, while 200µl had slight cytotoxic and genotoxic activity, therefore 100µl quantity was used for subsequent investigations. Cp had both cytotoxic and genotoxic activity. The effect of different combinations between carrot and Cp was studied (Using juice and mutagen together, treating cells with juice before and after mutagen treatment), the results revealed that carrot juice provided cells with high protection against cytotoxicity and genotoxicity, the protection effect ranged 80– 100 %.

Mutagenic Effect of Crucifers Lepidium sativum and Eruca sativa in Comparison to Carrot Daucus carota

The mutagenic effect of some crucifers widely consumed Lepiduim sativum (Garden cress) and Arugula (Eruca sativa) was studied in comparison to carrot (Daucus carota), using bacterial mutagenic system composed of three bacterial isolates; (Bacillus spp)G3 (Arthrobacter spp)G12, and (Brevibacterium spp)G27 ,. Treatment of isolates with plant extracts led to reduction in survival fraction (Sx)at different levels except that Aurgula extract did not show any inhibitory effect in isolates G12 and G27. Crucifers extracts induced streptomycin resistant mutants in G12 at higher level than G3 , but not in G27. No resistance to rifimpacin was detected in all isolates.

Mutagenic Effect of Crucifers Lepidium sativum and Eruca sativa in Comparison to Carrot Daucus carota

The mutagenic effect of some crucifers widely consumed Lepiduim sativum (Garden cress) and Arugula (Eruca sativa) was studied in comparison to carrot (Daucus carota), using bacterial mutagenic system composed of three bacterial isolates; (Bacillus spp)G3 (Arthrobacter spp)G12, and (Brevibacterium spp)G27 ,. Treatment of isolates with plant extracts led to reduction in survival fraction (Sx)at different levels except that Aurgula extract did not show any inhibitory effect in isolates G12 and G27. Crucifers extracts induced streptomycin resistant mutants in G12 at higher level than G3 , but not in G27. No resistance to rifimpacin was detected in all isolates.