Argentine Collection Research Articles

ВИВЧЕННЯ РІЗНОМАНІТТЯ ВІРУСІВ БАКТЕРІЙ, ВИДІЛЕНИХ ІЗ БІОТОПІВ МОХУ ТА ҐРУНТУ АНТАРКТИЧНОГО РЕГІОНУ

Until now, there is a little number of scientifically investigated phages, in comparison to other biological representatives of the micro and macro world. Their properties are well studies only for a small number of so-called model bacteriophages. At the same time, the extraction of phages from ecosystems that function in low temperatures represents considerable scientific interest and has some methodological difficulties. The aim of the research was to study the diversity of viruses of bacteria isolated from the moss and soil of Antarctic plants. Methods: isolation of bacteriophages from moss and soil specimens, titration by the Gratia method, accumulation of phages in a liquid nutrient medium with forced aeration, electron microscopy, statistical methods. Results: The isolation of bacterial viruses (bacteriophages) from moss and soil biotops has been carried out. The morphology of negative colonies and viral particles of obtained phage isolates is described. Start of the negative colonies formation was observed in 5–7 days, in others after 7–10 days. Their formation was completed after 10–12 days. The longest formation of negative colonies occurred precisely on strains of Antarctic bacterial cultures. Their taxonomic diversity is established. The detected viral particles were represented by different morphotypes, which are typical for the viruses of the families Myoviridae, Podoviridae and Siphoviridae of the Caudovirales order. Conclusions: isolates of phages to sensitive bacteria were extracted. A description of the diversity of bacteriophages has been made, which shows the taxonomic diversity of bacteriophages in the terrestrial biotopes of the islands of the Argentine archipelago and collection according to their characteristics was created.

Constituents of the Argentine Liverwort Plagiochila diversifolia and Their Insecticidal Activities.

Three new compounds, a bicyclogermacrene (1) and two 2,3-secoaromadendrane esters (2 and 3), together with (13S)-13-hydroxylabda-8,14-diene (4), fusicogigantone B (5), 3α,14-diacetoxy-2-hydoxybicyclogermacrene (6), fusicogigantone A (7), neofuranoplagiochilal (8), plagiochiline B (9), furanoplagiochilal (10), trans-nerolidol, spathulenol, α-tocopherol, and (+)-globulol were isolated from an Argentine collection of Plagiochila diversifolia. Their structures were elucidated by extensive mono and bidimensional NMR studies. Compounds 4, 5, and 6, incorporated to the larval diet at 100 μg per g of diet, reduced the larval growth of Spodoptera frugiperda (Lepidoptera: Noctuidae) by 70 ± 25, 57 ± 23, and 33 ± 16%, respectively. Compounds 4 and 5 produced 70% and 60% larval mortality at early instars. The latter also showed antifeedant properties in the Choice Test, with a feeding ratio of 0.54 ± 0.16.

A New Depigmenting-Antifungal Methylated Grindelane from Grindelia chiloensis.

The new methylated grindelane diterpenoid, 7β-hydroxy-8(17)-dehydrogrindelic acid (1b), together with the known 7α-hydroxy-8(17)-dehydrogrindelic acid (2a), 6-oxogrindelic acid (3a), 4β-hydroxy-6-oxo-19-norgrindelic (4a), 19-hydroxygrindelic acid (5a), 18-hydroxygrindelic acid (6a), 4α-carboxygrindelic acid (7a), 17-hydroxygrindelic acid (8a), 6α-hydroxygrindelic acid (9a), 8,17-bisnor-8-oxagrindelic acid (10a), 7α,8α-epoxygrindelic acid (11a), and strictanonic acid (12a) as methyl esters were obtained from an Argentine collection of Grindelia chiloensis (Cornel.) Cabrera. Their structures and relative configurations were established on the basis of spectroscopic analysis. CHCl3 extract from the aerial parts and their pure compounds were evaluated for their antifungal and depigmenting effects. Methyl ester derivative of 10a (10b) exhibited a remarkable mycelial growth inhibition against Botritis cinerea with an IC50 of 13.5μgml-1 . While the new grindelane 1b exerted a clear color reduction of the yellow-orange pigment developed by Fusarium oxysporum against UV-induced damage.

Bioactivity of the Essential Oil of an Argentine Collection of Acanthospermum hispidum (Asteraceae)

The essential oil of an Argentine collection of the annual herb Acanthospermum hispidum DC. (Asteraceae), which contains the sesquiterpenoids beta-caryophyllene (35.2%), alpha-bisabolol (11.4%), and germacrene D (11.1%) as major constituents, displayed molluscicidal effects on an adult population of Biomphalaria peregrina Orbigny (LD50 37.8 microg/mL) and produced alteration of the feeding and oviposition behavior of the polyphagous insect Spodoptera frugiperda Smith when incorporated in the larval diet at 250 microg/g. In addition, a selective antibacterial activity was observed against pathogenic strains of Staphylococcus aureus and Enterococcus faecalis (MICs 62.5 and 125 microg/mL), but was inactive at 125 microg/mL against three beneficial lactic acid bacteria. Synergistic interactions were further validated by FIC index determination of the combination of the antibiotics oxacillin and gentamicin and the essential oil on the four pathogenic strains evaluated.

Bioactive Sesqui- and Diterpenoids from the Argentine Liverwort Porella chilensis

Four fusicoccane-type diterpenoids (1-4), including the new 1 and 2; four pinguisane-type sesquiterpenoids (5-8); and two aromadendrane-type sesquiterpenoids (9 and 10) were isolated from an Argentine collection of the endemic liverwort Porella chilensis. The biofilm formation of the human pathogen Pseudomonas aeruginosa was inhibited by compounds 3 (53 and 47%), 9 (45 and 41%), and 10 (48 and 37%) at 50 and 5 μg/mL, respectively. Compounds 3, 9, and 10 also produced a slight decrease in bacterial growth and interfere with the process of quorum sensing at the same doses.

Structure-Molluscicidal Activity Relationships of Acylphloroglucinols from Ferns

The molluscicidal activity of 12 phloroglucinol derivatives previously isolated from Elaphoglossum piloselloides, E. gayanum, E. yungense, and E. lindbergii, as well as 3 known acylphloroglucinols, now reported from an Argentine collection of Dryopteris wallichiana, was evaluated against the schistosomiasis vector snail Biomphalaria peregrina. Molluscicidal effects were analyzed and compared with those previously observed for 4 acylphloroglucinols from E. piloselloides and their corresponding peracetylated derivatives, in order to draw structure-activity relationships. The most active compounds were the prenylated desaspidins elaphogayanin B and elaphopilosins A and B (LD50 = 1.90, 2.90, and 0.94 ppm, respectively), together with the only evaluated prenylated para-aspidin, elaphopilosin C (LD50 = 2.15 ppm). Quantitative structure-activity relationships (QSAR) were studied by means of a semiempirical method (PM3) for the 24 natural phloroglucinol derivatives included in this paper. The descriptor molecular volume was found to have good correlation with the observed molluscicidal activity (r2 = 0.77). The derived equation can be considered useful to predict the molluscicidal activity of bi and tricyclic acylphloroglucinols. The QSAR analysis showed that there is an optimum volume for high activity, probably related to the size of a receptor's active site. Bigger molecules display lower activity.

Antibacterial Prenylated Acylphloroglucinols from the Fern Elaphoglossum yungense

Seven new prenylated acylphloroglucinols, yungensins A-G, were isolated from the diethyl ether extract of the scaly rhizomes and roots of an Argentine collection of the fern Elaphoglossum yungense. All the compounds contained a geranyl group attached to the filicinic acid-type residue. The diethyl ether extract and yungensins A-F displayed antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa with MICs ranging from 10 to 200 μg/mL. All tested acylphloroglucinols, except for yungensin D, caused bacteriolysis of S. aureus at MBC or higher doses (50-200 μg/mL). At 10 μg/mL, the ether extract as well as yungensins A, B, and D-F altered the biofilm production in both microoganisms.

Two New Furanoeremophilanes from Senecio santelisis

From an Argentine collection of Senecio santelisis Phil., the new furanoeremophilanoids, (10betaH)-6beta-acetoxy-1alpha-hydroxyfuranoeremophilan-9-one (1) and (10betaH)-1alpha-hydroxy-6beta-(propanoyloxy)furanoeremophilan-9-one (2), together with the known (10alphaH)-6beta-acetoxy-1alpha-hydroxyfuranoeremophilan-9-one (3), (10alphaH)-1alpha,6beta-diacetoxyfuranoeremophilan-9-one (4), and (10alphaH)-1alpha-hydroxy-6beta-(propanoyloxy)furanoeremophilan-9-one (5) were isolated. Their structures and relative configurations were established on the basis of spectroscopic analysis. CHCl3 Extract and pure compounds were evaluated for their antifungal activity. Compound 5 exhibited remarkable mycelial growth inhibition against B. cinerea with an IC(50) value of 21.4 microg/ml.

Insecticidal Constituents from the Argentine Liverwort Plagiochila bursata

The new 2,3-secoaromadendrane 1, together with the known compounds plagiochilines A and M (2 and 3, resp.), fusicogigantone A (4), and 1,4-dimethylazulene (5) were isolated from an Argentine collection of the liverwort Plagiochila bursata. Structures were elucidated by extensive 1D- and 2D-NMR studies. Compounds 2 and 4, incorporated to the larval diet at 100 microg per g of diet, reduced the larval growth of Spodoptera frugiperda (Lepidoptera: Noctuidae) by 66+/-29% and 25+/-8% and produced 55 and 75% larval mortality at early instars and 20 and 25% pupal mortality, respectively. Treatment with compound 2 also produced abdomen and wing malformation in adults leading to impossibility to mate.

Molluscicidal Sesquiterpene Lactones from Species of the Tribe Vernonieae (Compositae)

Schistosomiasis is caused by parasitic flatworms of the genus Schistosoma, and some snails, particularly of the genus Biomphalaria (Planorbidae), are directly implicated in the transmission of the disease. Continuing with our investigations of bioactive plant constituents, we evaluated and report in the present article, the molluscicidal effects of 16 sesquiterpene lactones, as well as the commercial reagents tetrahydrofuran, furfural, and furfuryl alcohol, on an adult population of B. peregrina. The natural sesquiterpene lactones tested are characteristic constituents of species of the tribe Vernonieae, family Asteraceae. Compounds 1-3 and 7 came from a Bolivian collection of Vernonanthura pinguis, compounds 4 and 5 from an Argentine collection of Cyrtocymura cincta var. cincta, 6 was obtained from a Bolivian collection of Eirmocephala megaphylla, 8-14 from an Argentine collection of Centratherum punctatum ssp. punctatum, and compounds 15 and 16 were obtained by chemical derivatization from 5 and 14, respectively. Ten of the sesquiterpene lactones displayed moderate molluscicidal activity (LD50<100 microg/ml). Commercial reagents were inactive.

Molluscicidal Phloroglucinols from the Fern Elaphoglossum piloselloides

Two new bicyclic phloroglucinols were isolated from the diethyl ether extract of an Argentine collection of the fern Elaphoglossum piloselloides. Structures were established by analysis of their spectroscopic data ((1)H NMR, HRMS, IR) and chemical derivatization. Both compounds show an acute molluscicidal activity against the schistosomiasis vector snail Biomphalaria peregrina.

Effects of p-Vinylphenyl Glycosides and Other Related Compounds on the Oviposition Behavior of Ceratitis capitata

Elaphoside-A [p-vinylphenyl (beta-D: -glucopyranosyl)-(1-->3)-beta-D: -allopyranoside], a Mediterranean fruit fly oviposition deterrent, was previously isolated from an Argentine collection of the fern Elaphoglossum piloselloides. In order to establish the structural requirements for the observed oviposition inhibition, we synthesized and characterized 4 known and 21 new aromatic glycosides structurally related to elaphoside-A. Their effects on the oviposition behavior of Ceratitis capitata females are discussed.

Toxic effects of annonaceous acetogenins on Oncopeltus fasciatus

From an Argentine collection of Annona cherimolia and a Bolivian collection of Annona montana (Annonaceae), the acetogenins, squamocin, molvizarin, itrabin, almunequin, cherimolin-1, annonacin, annonacin-A, densicomacin-1, cis-annonacin-10-one and murihexocin-A, were obtained to study their toxicity against the cotton pest Oncopeltus fasciatus (Hemiptera: Lygaeidae). Topical ventral application of O. fasciatus nymphs with solutions of the mentioned acetogenins produced acute and delayed mortality.

Diterpenoid Glycosides from the Bitter Fern Gleichenia quadripartita

Fifteen new diterpenoid glycosides (1a-n, 2) were isolated from an Argentine collection of the bitter fern Gleichenia quadripartita along with the known flavonoid glycoside afzelin. Structure elucidation was accomplished by 1D and 2D NMR spectroscopy and by high-resolution MS analyses. In addition, X-ray crystallographic analysis of a monocrystal of 1a as well as chemical derivatization of 1h and 1m were performed to confirm their structures.

Antioxidant and XOD Inhibitory Coumarins from Pterocaulon polystachyum DC

The antioxidant capacity of prenyletin (6-hydroxy-7-isoprenyloxycoumarin (1), prenyletin-6-methylether (6-methoxy-7-isoprenyloxycoumarin (2), and ayapin (6,7-methylenedioxycoumarin (3), isolated from an Argentine collection of Pterocaulon polystachyum, was investigated. Compound 1 displayed a higher scavenging activity on DPPH (72%) and ABTS (89%), at 100 μg/mL, than 2 and 3. In the non-enzymatic system of O2•- generation, compound 1 scavenged (46%) superoxide radicals at a scavenging concentration (SC50) of 100 μg/mL. In addition, 1 inhibited 82% uric acid formation at 100 μg/mL, while allopurinol, employed as positive control, displayed 93% inhibition at the same concentration. The antioxidant ability of 1 is dose-dependant and apparently its OH group on C-6 is a structural requirement for the observed activity. A synergistic scavenging action of a ternary mixture (ratio 1:8:1) of 1, 2 and 3 was also observed.

Bioactive constituents from Rollinia emarginata (Annonaceae)

From an Argentine collection of the tropical tree Rollinia emarginata (Annonaceae), vomifoliol, dehydrovomifoliol, blumenol C, loliolide, 7-epiloliolide, vanillin, dihydroactinolide, as well as other common plant constituents were obtained, and identified by their NMR and MS features compared with authentic samples. Antifeedant and toxic actions were exerted to the polyphagous moth Spodoptera frugiperda by the ethanol extract of the plant, at 250 ppm in the larval diet. Additionally, in greenhouse studies, a 200 ppm aqueous solution of the extract produced a post-emergency herbicidal effect on the annual weed common lambsquarter (Chenopodium album).

Toxic effects of annonaceous acetogenins from Annona cherimolia (Magnoliales: Annonaceae) on Spodoptera frugiperda (Lepidoptera: Noctuidae)

Plants belonging to the family Annonaceae have been commonly described in traditional medicine as remedies against head lice, and for their insecticidal properties. Characteristic constituents from a few genera of these plants are the annonaceous acetogenins. Fourteen annonaceous acetogenins have been isolated from our Argentine collection of the seeds of A. cherimolia. We report herein the antifeedant and insecticidal effects of nine of those acetogenins on Spodoptera frugiperda (J. E. Smith). The acetogenin squamocin, one of the major constituents of the extract, displayed toxic effects on early larval instars when incorporated to the larval diet at a dose of 50 μg per g of diet. The remaining annonaceous acetogenins tested, itrabin, asimicin, neoanonin, cherimolin-1, cherimolin-2, almunequin, motrilin, and tucumanin produced pupal mortality and adult malformations leading to death, when incorporated to the larval diet at the same dose. The evaluation of indices of food consumption, growth, and food utilization indicated that squamocin was the only tested acetogenin to produce significant decrease in the growth rate and to reduce the efficiency with which larvae converted ingested food into biomass. All the acetogenins produced more than 80% pupal mortality with no dependence on the position of the THF rings or the number and location of the OH groups.

Drimanes and Other Terpenoids from the FernThelypteris hispidula (Decne.)Reed

The drimane-type sesquiterpenoids (-)-polygodial (1), (-)-isopolygodial (4), drimenin (5), and isodrimenin (6) were isolated from a pungent Argentine collection of the fern Thelypteris hispidula, along with other terpenoids. As the mentioned drimanes have been previously found in liverworts, the present results strongly support the theory that Pteridophytes and Bryophytes share the same line of evolution. Our present investigations indicate that two chemotypes of T. hispidula are widespread in the northwest of Argentina. Plants belonging to the pungent chemotype contain drimanes, while nonpungent plants lack drimanes.

Manoyl Oxide Diterpenoids from Grindelia scorzonerifolia

Two new norditerpenoids, 4beta-hydroxy-19-normanoyl oxide (1) and 4alpha-hydroxy-18-normanoyl oxide (2), the new 18-O-alpha-l-arabinopyranosylmanoyl oxide (3a), and the known diterpenoids jhanol (4) and 18-hydroxy-13-epi-manoyl oxide (5) were isolated, together with other common plant constituents from an Argentine collection of Grindelia scorzonerifolia. The structures of the new compounds were established by extensive 1D and 2D NMR techniques and chemical transformations. Structural features of compounds 2 and 4 were verified by X-ray crystallographic analyses. The insecticidal effect of compound 3a was evaluated against the polyphagous pest Spodoptera frugiperda. Pupal and adult malformations leading to death occurred when 3a was incorporated in a larval diet at a concentration of 100 ppm.

Africane-type sesquiterpenoids from the Argentine liverwort Porella swartziana and their antibacterial activity.

Seven africanes (1, 2a,b, 3-6), two of them new (1, 2a), three secoafricanes (7-9), one of them new (7), and two norsecoafricanes (10, 11a), one of them new (10), all of them swartzianin-type, have been isolated from an Argentine collection of the endemic liverwort Porella swartziana. The structures of the new compounds were established by extensive 1D and 2D NMR spectroscopic data. Absolute configurations of compounds 2a, 2b, and 10 were derived on the basis of CD spectra. The compounds were tested for activity against a variety of microbes, but none were found to exhibit significant antibacterial activity.