Cultivable gut bacteria provide a pathway for adaptation of Chrysolina herbacea to Mentha aquatica volatiles.

BACKGROUND: A chemical cross-talk between plants and insects is required in order to achieve a successful co-adaptation. In response to herbivory, plants produce specific compounds, and feeding insects respond adequately7 to molecules produced by plants. Here we show the role of the gut microbial community of the mint beetle Chrysolina herbacea in the chemical cross-talk with Mentha aquatica (or watermint). RESULTS: By using two-dimensional gas chromatography-mass spectrometry we first evaluated the chemical patterns of both M. aquatica leaf and frass volatiles extracted by C. herbacea males and females feeding on plants, and observed marked differences between males and females volatiles. The sex-specific chemical pattern of the frass paralleled with sex-specific distribution of cultivable gut bacteria. Indeed, all isolated gut bacteria from females belonged to either α- or γ-Proteobacteria, whilst those from males were γ-Proteobacteria or Firmicutes. We then demonstrated that five Serratia marcescens strains from females possessed antibacterial activity against bacteria from males belonging to Firmicutes suggesting competition by production of antimicrobial compounds. By in vitro experiments, we lastly showed that the microbial communities from the two sexes were associated to specific metabolic patterns with respect to their ability to biotransform M. aquatica terpenoids, and metabolize them into an array of compounds with possible pheromone activity. CONCLUSIONS: Our data suggest that cultivable gut bacteria of Chrysolina herbacea males and females influence the volatile blend of herbivory induced Mentha aquatica volatiles in a sex-specific way.

Facile synthesis, cytotoxic and antimicrobial activity studies of a new group of 6-aryl-3-[4-(methylsulfonyl)benzyl]-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines.

The reaction of 4-(methylsulfonyl)phenylacetohydrazide (3) with carbon disulfide and potassium hydroxide followed by hydrazine hydrate gave 4-amino-5-[4-(methylsulfonyl)benzyl]-4H-[1,2,4]triazole-3-thione (4). The resulting triazole was subjected to cyclocondensation reaction with different phenacyl bromides to afford 6-substituted-3-[4-(methylsulfonyl)benzyl]-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines (5a-i). All structures of the newly synthesized compounds were confirmed by IR, NMR, mass spectral studies and elemental analyses. The newly synthesized compounds were screened for their cytotoxic, antibacterial and antifungal activity. Some of the derivatives have exhibited promising biological activity.

Facile synthesis, characterization and pharmacological activities of 3,6-disubstituted 1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles and 5,6-dihydro-3,6-disubstituted-1,2,4-triazolo[3,4-b][1,3,4]thiadiazoles.

Two new series of compounds namely, 3,6-disubstituted-1,2,4-triazolo[3,4-b][1,3,4]thiadizoles (5a-j) and 5,6-dihydro-3,6-disubstituted-1,2,4-triazolo[3,4-b][1,3,4]thiadizoles (7a-j) were prepared. In continuation of a previously reported study, the first series (5a-j) were synthesized by the cyclocondensation of 4-amino-5-(2-bromo-5-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (4) with various substituted aromatic carboxylic acids in phosphorus oxychloride and the second series (7a-j) by the reaction of (4) with various substituted aromatic aldehydes in the presence of p-Toluene sulfonic acid. Reaction of (4) with the aldehyde (9) afforded the Schiff's base (10) and not the cyclised product (11) on treatment with p-Toluene sulfonic acid. Synthesized compounds were structurally confirmed by spectral analysis and studied for their anti-inflammatory, analgesic, anti-oxidant and antimicrobial activities. Some of the tested compounds showed significant pharmacological activities.

6-Chloro-2-cyclo-propyl-4-(trifluoro-meth-yl)quinoline.

In the title compound, C(13)H(9)ClF(3)N, the quinoline ring system makes a dihedral angle of 88.8 (2)° with the cyclo-propyl ring.

1-Chloro-4-(3,4-dichloro-phen-yl)-3,4-dihydro-naphthalene-2-carbaldehyde.

The title compound, C(17)H(11)Cl(3)O, was synthesized via the Vilsmeier-Haack reaction. The dihydro-naphthalene ring system is non-planar, the dihedral angle between the two fused rings being 10.87 (13)°; it forms a dihedral angle of 81.45 (10)° with the dichloro-phenyl ring. The crystal structure features inter-molecular C-H⋯O hydrogen bonds.

Synthesis and antimicrobial activity of 1,2,3-triazoles containing quinoline moiety.

A new series of substituted 1,2,3-triazoles (4a-n) were synthesized from 4-azido-2,8-bistrifluoromethylquinoline 2. The 1,3-dipolar cycloaddition reaction of 2 with ethyl acetoacetate afforded 1-(2,8-Bistrifluoromethylquinolin-4-yl)-5-methyl-1,2,3-triazole-4-carboxylic acid 3, which was then converted into its corresponding acid hydrazide 3a. Condensation of this hydrazide with different aromatic aldehydes resulted in the formation of Schiff's bases, N-[1-Arylmethylene]-1-[2,8-bistrifluoromethylquinoline-4-yl]-5-methyl-1H-1,2,3-triazole-4-carbohydrazides (4a-n). These newly synthesized 1,2,3-triazole derivatives were characterized by analytical and spectral data. All the synthesized compounds were evaluated in vitro for their antibacterial and antifungal activity. A brief investigation of the structure activity relationships revealed that the nature of the substituent on position 4 of the triazole ring influences the antimicrobial activity. Among the newly synthesized compounds, the most active compound was 4n, which contained the 3-methylthien-2-yl moiety and showed a broad spectrum of antimicrobial activity against all the strains used for testing. Compounds 4b, 4c, 4e, 4f, 4h and 4l showed significant antimicrobial activity at the concentration of 6.25 µg/mL.