Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination

As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose.     

Effect of some essential oils on in vitro methane emission

The objectives of this study were to characterise four essential oils (EO) chemically and to evaluate their effect on ruminal fermentation and methane emission in vitro. The investigated EO were isolated from Achillea santolina, Artemisia judaica, Schinus terebinthifolius and Mentha microphylla, and supplemented at four levels (0, 25, 50 and 75 microl) to 75 ml of buffered rumen fluid plus 0.5 g of substrate. The main components of the EO were piperitone (49.1%) and camphor (34.5%) in A. judaica, 16-dimethyl 15-cyclooactdaiene (60.5%) in A. santolina, piperitone oxide (46.7%) and cis-piperitone oxide (28%) in M. microphylla, and gamma-muurolene (45.3%) and alpha-thujene (16.0%) in S. terebinthifolius. The EO from A. santolina (at 25 and 50 j1), and all levels of A. judaica increased the gas production significantly, but S. terebinthifolius (at 50 and 75 microl), A. santolina (at 75 microl) and all levels of M. microphylla decreased the gas production significantly in comparison with the control. The highest levels of A. santolina and A. judaica, and all doses from M. microphylla EO inhibited the methane production along with a significant reduction in true degradation of dry matter and organic matter, protozoa count and NH3-N concentration. It is concluded that the evaluated EO have the potential to affect ruminal fermentation efficiency and the EO from M. microphylla could be a promising methane mitigating agent.     

Essential oils from wild populations of Algerian Lavandula stoechas L.: composition, chemical variability, and in vitro biological properties

In an effort to develop local productions of aromatic and medicinal plants, a comprehensive assessment of the composition and biological activities of the essential oils (EOs) extracted from the aerial flowering parts of wild growing Lavandula stoechas L. collected from eleven different locations in northern Algeria was performed. The oils were characterized by GC‐FID and GC/MS analyses, and 121 compounds were identified, accounting for 69.88–91.2% of the total oil compositions. The eleven oils greatly differed in their compositions, since only 66 compounds were common to all oils. Major EO components were fenchone ( 2 ; 11.27–37.48%), camphor ( 3 , 1.94–21.8%), 1,8‐cineole ( 1 ; 0.16–8.71%), and viridiflorol ( 10 ; 2.89–7.38%). The assessed in vitro biological properties demonstrated that the DPPH‐based radical‐scavenging activities and the inhibition of the β‐carotene/linoleic acid‐based lipid oxidation differed by an eight‐fold factor between the most and the least active oils and were linked to different sets of molecules in the different EOs. The eleven EOs exhibited good antimicrobial activities against most of the 16 tested strains of bacteria, filamentous fungi, and yeasts, with minimum inhibitory concentrations (MICs) ranging from 0.16 to 11.90 mg/ml.     

Effect of Feeding Palm Oil By-Products Based Diets on Total Bacteria,Cellulolytic Bacteria and Methanogenic Archaea in the Rumen of Goats

Rumen microorganisms are responsible for digestion and utilization of dietary feeds by host ruminants. Unconventional feed resources could be used as alternatives in tropical areas where feed resources are insufficient in terms of quality and quantity. The objective of the present experiment was to evaluate the effect of diets based on palm oil (PO), decanter cake (DC) or palm kernel cake (PKC) on rumen total bacteria, selected cellulolytic bacteria, and methanogenic archaea. Four diets: control diet (CD), decanter cake diet (DCD), palm kernel cake diet (PKCD) and CD plus 5% PO diet (CPOD) were fed to rumen cannulated goats and rumen samples were collected at the start of the experimental diets (day 0) and on days 4, 6, 8, 12, 18, 24 and 30 post dietary treatments. Feeding DCD and PKCD resulted in significantly higher (P<0.05) DNA copy number of total bacteria, Fibrobacter succinogenes, Ruminococcus flavefeciens, and Ruminococcus albus. Rumen methanogenic archaea was significantly lower (P<0.05) in goats fed PKCD and CPOD and the trend showed a severe reduction on days 4 and 6 post experimental diets. In conclusion, results indicated that feeding DCD and PKC increased the populations of cellulolytic bacteria and decreased the density of methanogenic archaea in the rumen of goats.     

Postinoculation protozoan establishment and association patterns of methanogenic archaea in the ovine rumen

Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.     

Chemical composition and antigenotoxic properties of Lippia alba essential oils

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds.     

Effects of vanillin, quillaja saponin, and essential oils on in vitro fermentation and protein-degrading microorganisms of the rumen

This study investigated the effects of vanillin on methanogenesis and rumen fermentation, and the responses of ruminal protein-degrading bacteria to vanillin (at concentrations of 0, 0.76 and 1.52 g/L), essential oils (clove oil, 1 g/L; origanum oil, 0.50 g/L, and peppermint oil, 1 g/L), and quillaja saponin (at concentration of 0 and 6 g/L) in vitro. Methane production, degradabilities of feed substrate, and ammonia concentration decreased linearly with increasing doses of vanillin. Concentration of total volatile fatty acids also decreased, whereas proportion of butyrate tended to increase linearly with increasing doses of vanillin. Protozoa population decreased, but abundances of Ruminococcus flavefaciens, Prevotella bryantii, Butyrivibrio fibrisolvens, Prevotella ruminicola, Clostridium aminophilum, and Ruminobacter amylophilus increased with increasing doses of vanillin. Origanum and clove oils resulted in lower ammonia concentrations compared to control and peppermint oil. All the tested essential oils decreased abundances of protozoa, Selenomonas ruminantium, R. amylophilus, P. ruminicola and P. bryantii, with the largest decrease resulted from origanum oil followed by clove oil and peppermint oil. The abundances of Megasphaera elsdenii, C. aminophilum, and Clostridium sticklandii were deceased by origanum oil while that of B. fibrisolvens was lowered by both origanum and clove oils. Saponin decreased ammonia concentration and protozoal population, but increased the abundances of S. ruminantium, R. amylophilus, P. ruminicola, and P. bryantii, though the magnitude was small (less than one log unit). The results suggest that reduction of ammonia production by vanillin and saponin may not be caused by direct inhibition of major known proteolytic bacteria, and essential oils can have different inhibitory effects on different proteolytic bacteria, resulting in varying reduction in ammonia production.     

Inhibitory efficacy of different essential oils against storage carrot rot with antifungal and resistance‐inducing potential

The inhibitory effects of essential oils (EOs) derived from coriander, lavender, geranium, thyme, savoury and eucalyptus were assessed against Sclerotinia sclerotiorum, the causal agent of carrot white mould. All EOs showed antifungal activity against the pathogen in vitro and in vivo. In addition, all EOs markedly increased 6‐methoxymellein in the treated carrots. The EOs of thyme and savoury were found to be more effective than other tested EOs. The enzymatic tests showed that thyme and savoury EOs were more able than lavender EO to significantly increase the level of chitinases, peroxidases, β‐1,3‐glucanases, polyphenol oxidase, peroxidase and phenylalanine ammonia‐lyase in the treated carrots, indicating that the EOs of thyme and savoury have potential to be considered as effective inducers of resistance against carrot white mould. In this study, all EOs inhibited myceliogenic and carpogenic germination of sclerotia at concentrations 1 and 10 µl/ml sterile distilled water, respectively. After gas chromatography/mass spectrometry, major component in the thyme EO was found to be thymol (39.15%) followed by p‐cymene (13.85%) and carvacrol (10.36%), while in savoury EO were carvacrol (41.9%), γ‐terpinene (17.38) and p‐cymene (11.25%).     

Chemical Compositions,Antioxidant and Antimicrobial Activities of Essential Oils of Psidium guajava L. Leaves from Different Geographic Regions in China

Hydrodistilled essential oils (EO) of Psidium guajava L. leaves from different regions in China were analyzed by GC and GC/MS. The samples from Guangdong Province displayed high EO yields (0.61 – 0.75%, v/w). A total of 50 components, representing over 98.00% of the EOs, were identified and semi‐quantitatived. The major constituents of EOs included β‐caryophyllene (17.17 – 31.38%), γ‐gurjunene (9.17 – 15.22%), τ‐cadinol (1.35 – 10.02%) and calamenene (2.13 – 7.80%). The terpenoids in all sample oils were dominated by sesquiterpenes hydrocarbons (70.18 – 84.35%), followed by oxygenated sesquiterpenes (9.89 – 22.19%). The similarities and differences among EOs from different samples were evaluated by hierarchical cluster analysis and principal component analysis methods. The IC₅₀ values of EOs from different regions were between 18.52 – 33.72 mg/ml (DPPH) and 13.12 – 25.15 mg/ml (ABTS⁺). The FRAP value of EO from Guangdong Province was 7.34 – 9.13 mmol Vc/g DM, while the FRAP value of EO from Taiwan Province was 2.29 – 2.36 mmol Vc/g DM. The antimicrobial tests revealed that EO had a higher antimicrobial activity against all Gram‐positive bacteria and two fungi. Moreover, EO from P. guajava leaves of Guangdong Province showed the highest antimicrobial activity. These properties can be considered in the design of industrial products and for further application in the food, pharmaceutical and cosmetic industries.     

Contribution of Constituents in Rosemary-Magnolia Compound Essential Oil to Antibacterial,Antioxidant and Cytotoxicity Bioactivities Revealed by Grey Correlation Analysis

The compound of essential oils (EOs) is a key approach to achieving the superimposed efficacy of plant EOs. In this article, grey correlation analysis was applied for the first time to explore the compound ratios and contribution between constituents and the bioactivity of the compound EOs. There were 12 active constituents shared in rosemary and magnolia EOs prepared by negative pressure distillation. With different proportions, these two EOs were blended and analyzed for the antioxidant, bacteriostatic and antitumor effects. According to the results of the inhibition circle, minimum bactericidal and inhibitory concentration, the most obvious inhibition effect of the compound EOs on different strains of bacteria was shown in Staphylococcus aureus. The results of antioxidant test showed that single EO from rosemary had the best antioxidant effect, and its EO content was directly proportional to the antioxidant effect. The cytotoxicity results showed that, there was a significant difference in the lethality of the compound EOs between tumor cells Mcf-7 (human breast cancer cells) and SGC-7901 cells (human gastric cancer cells). Furthermore, single EO from magnolia had an obvious inhibitory effect on the growth of Mcf-7 cells and SGC-7901 cells, and the cell lethality rate was as high as 95.19 % and 97.96 %, respectively. As the results of grey correlation analysis, the constituents with the maximal correlation of inhibitory effects on bacteria were as follows: S. aureus – Terpinolene (0.893), E. coli – Eucalyptol (0.901), B. subtilis – α-Pinene (0.823), B. cereus – Terpinolene (0.913) and Salmonella – α-Phellandrene (0.855). For the ABTS and DPPH scavenging effects, the constituents with the maximal correlation were (−)-Camphor (0.860) and β-Pinene (0.780), respectively. In terms of the effects of the active constituents of compound EOs on the inhibitory activities of tumor cells Mcf-7 and SGC-7901, the three active constituents of γ-Terpinene, (R)-(+)-β-Citronellol and (−)-Camphor were in the top three, and their correlation were Mcf-7 (0.833, 0.820, 0.795) and SGC-7901 (0.797, 0.766, 0.740). Our study determined the contribution degree of active constituents in the antibacterial, antioxidant, and antitumor bioactivities of rosemary-magnolia compound EOs, and also provided new insights for the research of EOs combination formulations.     

Essential Oil of Azorella cryptantha Collected in Two Different Locations from San Juan Province, Argentina: Chemical Variability and Anti-Insect and Antimicrobial Activities

The essential oils (EOs) of two populations of Azorella cryptantha (Clos) Reiche, a native species from San Juan Province, were obtained by hydrodistillation in a Clevenger-type apparatus and characterized by GC-FID and GC/MS analyses. The compounds identified amounted to 92.3 and 88.7% of the total oil composition for A. cryptantha from Bauchaceta (Ac-BAU) and Agua Negra (Ac-AN), respectively. The EO composition for the two populations was similar, although with differences in the identity and content of the main compounds and also in the identity of minor components. The main compounds of the Ac-BAU EO were α-pinene, α-thujene, sabinene, δ-cadinene, δ-cadinol, trans-β-guaiene, and τ-muurolol, while α-pinene, α-thujene, β-pinene, γ-cadinene, τ-cadinol, δ-cadinene, τ-muurolol, and a not identified compound were the main constituents of the Ac-AN EO, which also contained 3.0% of oxygenated monoterpenes. The repellent activity on Triatoma infestans nymphs was 100 and 92% for the Ac-AN and Ac-BAU EOs, respectively. Regarding the toxic effects on Ceratitis capitata, the EOs were very active with LD(50) values lower than 11?μg/fly. The dermatophytes Microsporum gypseum, Trichophyton rubrum, and T. mentagrophytes and the bacterial strains Escherichia coli LM(1) , E. coli LM(2) , and Yersinia enterocolitica PI were more sensitive toward the Ac-AN EO (MIC 125?μg/ml) than toward the Ac-BAU EO. This is the first report on the composition of A. cryptantha EO and its anti-insect and antimicrobial properties.     

Effect of tea saponin on methanogenesis,microbial community structure and expression of mcrA gene,in cultures of rumen micro‐organisms

Aims: To determine the in‐vitro effect and mode of action of tea saponin on the rumen microbial community and methane production. Methods and Results: Saponin extracted from tea seeds was added to (1) an in‐vitro fermentation inoculated with rumen fluid and (2) a pure culture of Methanobrevibacter ruminantium. Methane production and expression of the methyl coenzyme‐M reductase subunit A (mcrA) were monitored in both cultures. Abundance of methanogens, protozoa, rumen fungi and cellulolytic bacteria were quantified using real‐time PCR, and bacterial diversity was observed using denaturing gradient gel electrophoresis. Addition of tea saponin significantly reduced methane production and mcrA gene expression in the ruminal fermentation but not with the pure culture of M. ruminantium. The abundance of protozoa and fungi were significantly decreased 50% and 79% respectively but methanogen numbers were not affected, and Fibrobacter succinogenes increased by 41%. Bacterial diversity was similar in cultures with or without tea saponin. Conclusions: Tea saponin appeared to reduce methane production by inhibiting protozoa and presumably lowering methanogenic activity of protozoal‐associated methanogens. Significance and Impact of the Study: Tea saponin may be useful as a supplement to indirectly inhibit methane production in ruminants without a deleterious effect on rumen function.     

Chemical Composition and Activity of Essential Oils of Carissa macrocarpa (Eckl.) A.DC. Cultivated in Tunisia and Its Anatomical Features

This is the first study investigating the chemical composition of essential oils (EOs) isolated from different tissues of Carissa macrocarpa (Eckl .) A.DC., their antimicrobial activity and the anatomical characters of the aerial organs and the fruits. The main EO components were pentadecanal and tetradecan‐1‐ol (31.9 and 16.5% in fresh leaf EO, respectively), (E)‐nerolidol and caryophyllene oxide (27.3 and 15.0% in fruit EO, respectively), linalool and hexahydrofarnesyl acetone (30.9 and 24.9% in stem EO, respectively), benzyl benzoate (24.3% in flower EO). The fruit EO was more active against Candida albicans (MIC = 0.46 mg/mL) compared to the reference antibiotic (17.66 mg/mL). Furthermore, at this concentration it inhibited all the Gram‐positive bacteria. Concerning the anatomical features, it is noteworthy to mention the presence of a large cluster of calcium oxalate crystals inside some parenchymatous cells. Large ducts corresponding to non articulated laticifers were identified in the cortex of leaf, stem and fruit pericarp. The laticifers categories and their distribution are taxonomically important to discriminate this species from others acclimated in different countries. Considering the obtained results, EOs of C. macrocarpa can be a good source of antimicrobial compounds, contributing to solve the problem of microbial resistance to antibiotics.     

Chemical Composition of Magonia pubescens Essential Oils and Gamma-Radiation Effects on Its Constituents and Cytotoxic Activity in Leukemia and Breast Cancer Model

Magonia pubescens A. St.-Hil. is a Brazilian species often used in ethnopharmacology for wound and pain healing and seborrhea treatment. For the first time, essential oils (EOs) obtained from M. pubescens inflorescences were studied. The plant materials (Montes Claros, Brazil, 2018) were submitted to different gamma-radiation doses and their chemical compositions were analyzed by GC/MS and GC-FID. The cytotoxic activity of the EOs was evaluated against K562 and MDA-MB-231 cancer cell lines. A total of 30 components were identified, being 24 compounds detected for the first time in M. pubescens. The main obtained components were hotrienol (35.9 %), cis-linalool oxide (17.0 %) and trans-linalool oxide (10.2 %). The chemical composition of the EO was slightly affected by the applied radiation doses. Irradiated and non-irradiated EOs showed cytotoxic activity against both cell lines and the non-irradiated EO sample was the most active against the K562 cell lines (IC₅₀=22.10±1.98).     

Ruminal cellulolytic bacteria and protozoa from bison, cattle-bison hybrids, and cattle fed three alfalfa-corn diets

Ruminal cellulolytic bacteria and protozoa and in vitro digestibility of alfalfa fiber fractions were compared among bison, bison hybrids, and crossbed cattle (five each) when they were fed alfalfa and corn in a ratio of 100:0, 75:25, and 50:50, respectively. The total number of viable bacteria (2.16 x 10(9) to 5.44 x 10(9)/ml of ruminal fluid) and the number of cellulolytic bacteria (3.74 x 10(7) to 10.9 x 10(7)/ml) were not different among groups of animals fed each diet. The genera of protozoa in all of the animal groups were similar; however, when either the 100:0 or 50:50 diet was used the percentage of Entodinium sp. was lower and the percentage of Diplodiniinae was higher (P less than 0.05) in bison than in bison hybrids or cattle. Bacteroides succinogenes made up the largest number of cellulolytic isolates from bison (58 and 36%, respectively, on the 100:0 and 75:25 diets), which were more numerous (P less than 0.05) than those from bison hybrids (36 and 12%) and cattle (33 and 18%). This was offset by a lower number of cellulolytic Butyrivibrio isolates. The numbers of Ruminococcus albus and R. flavefaciens isolates, in general, were similar among the bovid species, although R. flavefaciens generally made up less than 10% of the cellulolytic isolates. In vitro digestibility coefficients were greater (P less than 0.05) for the bison when the 75:25 diet was used and similar for the other two diets. The concentration of ruminal volatile fatty acids was larger (P less than 0.05) in bison than in bison hybrids and cattle when the 50:50 diet was used.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ruminal cellulolytic bacteria and protozoa from bison, cattle-bison hybrids, and cattle fed three alfalfa-corn diets.

Ruminal cellulolytic bacteria and protozoa and in vitro digestibility of alfalfa fiber fractions were compared among bison, bison hybrids, and crossbed cattle (five each) when they were fed alfalfa and corn in a ratio of 100:0, 75:25, and 50:50, respectively. The total number of viable bacteria (2.16 x 10(9) to 5.44 x 10(9)/ml of ruminal fluid) and the number of cellulolytic bacteria (3.74 x 10(7) to 10.9 x 10(7)/ml) were not different among groups of animals fed each diet. The genera of protozoa in all of the animal groups were similar; however, when either the 100:0 or 50:50 diet was used the percentage of Entodinium sp. was lower and the percentage of Diplodiniinae was higher (P less than 0.05) in bison than in bison hybrids or cattle. Bacteroides succinogenes made up the largest number of cellulolytic isolates from bison (58 and 36%, respectively, on the 100:0 and 75:25 diets), which were more numerous (P less than 0.05) than those from bison hybrids (36 and 12%) and cattle (33 and 18%). This was offset by a lower number of cellulolytic Butyrivibrio isolates. The numbers of Ruminococcus albus and R. flavefaciens isolates, in general, were similar among the bovid species, although R. flavefaciens generally made up less than 10% of the cellulolytic isolates. In vitro digestibility coefficients were greater (P less than 0.05) for the bison when the 75:25 diet was used and similar for the other two diets. The concentration of ruminal volatile fatty acids was larger (P less than 0.05) in bison than in bison hybrids and cattle when the 50:50 diet was used.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen

Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.     

Essential oils of medicinal plants from the central andes of Argentina: chemical composition, and antifungal, antibacterial, and insect-repellent activities

The antifungal, antibacterial, and insect‐repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000 μg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC‐FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli‐1(6)‐en‐5‐one, and terpinen‐4‐ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector‐control.     

Artemisia arborescens Essential Oil Composition,Enantiomeric Distribution,and Antimicrobial Activity from Different Wild Populations from the Mediterranean Area

Aerial parts of Artemisia arborescens were collected from different sites of the Mediterranean area (southwestern Algeria and southern Italy) and the chemical composition of their essential oil (EO) extracted by hydrodistillation was studied by both gas chromatography (GC) equipped with an enantioselective capillary column and GC/mass spectrometry (GC/MS). The EOs obtained were tested against several Listeria monocytogenes strains. Using GC and GC/MS, 41 compounds were identified, accounting for 96.0 – 98.8% of the total EO. All EOs showed a similar terpene profile, which was rich in chamazulene, β‐thujone, and camphor. However, the concentration of such compounds varied among the EOs. A. arborescens EO inhibited up to 83.3% of the L. monocytogenes strains, but the inhibitory spectrum varied among the EOs, with those from Algeria showing a higher inhibition degree than the Italian EOs. Such effect likely depended on the ketone (β‐thujone + camphor) content of the EO. The differences in the EO composition support the hypothesis that A. arborescens has at least two different chemotypes: a β‐thujone and a chamazulene type. The EO inhibitory spectrum indicates the A. arborescens EO as a valuable option in the control of the food‐borne pathogens.     

Incorporation of [(15)N] ammonia by the cellulolytic ruminal bacteria Fibrobacter succinogenes BL2, Ruminococcus albus SY3, and Ruminococcus flavefaciens 17

The origin of cell nitrogen and amino acid nitrogen during growth of ruminal cellulolytic bacteria in different growth media was investigated by using (15)NH(3). At high concentrations of peptides (Trypticase, 10 g/liter) and amino acids (15.5 g/liter), significant amounts of cell nitrogen of Fibrobacter succinogenes BL2 (51%), Ruminococcus flavefaciens 17 (43%), and Ruminococcus albus SY3 (46%) were derived from non-NH(3)-N. With peptides at 1 g/liter, a mean of 80% of cell nitrogen was from NH(3). More cell nitrogen was formed from NH(3) during growth on cellobiose compared with growth on cellulose in all media. Phenylalanine was essential for F. succinogenes, and its (15)N enrichment declined more than that of other amino acids in all species when amino acids were added to the medium.