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Bibenzyls are a specialized metabolite class found throughout the plant kingdom. One of the most prolific producers of bibenzyls are liverworts, specifically plants of the Radula genera. These plants possess an incredible diversity of bibenzyls, prenylated bibenzyls, and a few (bis)bibenzyls, several of which have medicinal properties, including perrottetinene, an analog of tetrahydrocannabinol from cannabis. To provide insight into the bibenzyls' biosynthesis in planta, exogenous phytohormones were applied to in vitro grown Radula complanata and bibenzyl metabolite production was monitored with targeted and untargeted metabolomics. The targeted metabolomic analysis of six prenylated bibenzyls revealed that production of these metabolites was largely reduced when plants were treated with abscisic acid (AA), salicylic acid (SA), 1-naphthaleneacetic acid (NAA), or 6-benzylaminopurine (BAP). The reduction of these metabolites in the BAP and NAA treatment suggests that prenylated bibenzyl production is negatively correlated with vegetative plant growth. The reduction of bibenzyls at low AA and SA concentrations and mild increase at higher AA and SA concentrations suggest that their production is regulated by these stress hormones. In addition, six other bibenzyl metabolites were tentatively identified from the untargeted analysis. These results provide insight into the influence of phytohormones on the bioactive bibenzyl content of R. complanata. Key words: liverwort, Radula complanata, prenylated bibenzyl, specialized metabolism, phytohormones, metabolomics, Introduction Liverworts (Phylum Marchantiophyta) are a widely distributed phylum of nonvascular plants that fall under the bryophyte classification (Soderstrom et al. 2016). They are incredibly chemically diverse plants and possess [...]

The filter-feeding ciliate Tetrahymena pyriformis is a popular organism for the study of phagocytosis. Nevertheless, fundamental questions remain as to how ingestion is triggered. Some have found that a particle's [...]

Little is known about the sources of cytosolic acetyl-CoA used for the synthesis of malonyl-CoA, a key regulator of fatty acid oxidation in the heart. We tested the hypothesis that citrate provides acetyl-CoA for malonyl-CoA synthesis after its mitochondrial effiux and cleavage by cytosolic ATP-citrate lyase. We expanded on a previous study where we characterized citrate release from perfused rat hearts (Vincent G, Comte B, Poirier M, and Des Rosiers C. Citrate release by perfused rat hearts: a window on mitochondrial cataplerosis. Am J Physiol Endocrinol Metab 278: E846-E856, 2000). In the present study, we show that citrate release rates, ranging from 6 to 22 nmol/min, can support a net increase in malonyl-CoA concentrations induced by changes in substrate supply, at most 0.7 nmol/min. In experiments with [U-[sup.13]C](lactate + pyruvate) and [1-[sup.13]C]oleate, we show that the acetyl moiety of malonyl-CoA is derived from both pyruvate and long-chain fatty acids. This [sup.13]C-labeling of malonyl-CoA occurred without any changes in its concentration. Hydroxycitrate, an inhibitor of ATP-citrate lyase, prevents increases in malonyl-CoA concentrations and decreases its labeling from [U-[sup.13]C](lactate + pyruvate). Our data support at least a partial role of citrate in the transfer from the mitochondria to cytosol of acetyl units for malonyl-CoA synthesis. In addition, they provide a dynamic picture of malonyl-CoA metabolism: even when the malonyl-CoA concentration remains constant, there appears to be a constant need to supply acetyl-CoA from various carbon sources, both carbohydrates and lipids, for malonyl-CoA synthesis. gas chromatography-mass spectrometry; adenosine 5'-triphosphate-citrate lyase; hydroxycitrate; acetyl-coenzyme A; citric acid cycle; [sup.13]C-substrate; isotopomer analysis

The authors review the publications on organic nitroso compound chemistry. The topics of interest include the syntheses and properties of the organic compounds and their reactions with metal centers.

Research reveals a negative regulator of the organic hydroperoxide resistance (ohr) gene, OhrR, in an operon association with ohr in Xanthomonas compestris pv. Phaseoli. Transcriptional analysis of ohr and ohrR suggest that ohr expression is regulated by ohrR promoter in combination with an RNA processing step.

The focus of this article is the to review the experimental thermochemical studies of the aromatic character of the organic compounds. The comparison of the thermochemical description of aromaticity and other criteria such as magnetic, spectroscopic and structural properties have been performed and analyzed.

Research has been conducted on the 1,3-proton migration. The mechanistic study of this migration in a series of dithiepines is presented.

Research has been conducted on the substituted 1-vinyl-1-(3-butenyl)cycloalkanes. The formation of the silylated spirocycles with excellent regio and diastereoselectivity has been carried out via the cyclization/hydrosilylation of these substituted 1-vinyl-1-(3-butenyl)cycloalkanes and the results are discussed.

Results demonstrate that organic hydroperoxide resistance (ohr) gene encoded product is involved in the decomposition (resistance) of organic hydroperoxides. Data reveal that upon exposure to organic hydroperoxides, a 15-fold increase in the transcriptional activity of ohr is observed.

Results demonstrate that the glutathione-dependent formaldehyde dehydrogenase sensor-regulator is a two-component system that regulates oxidation of formaldehyde, methanol, and methylamine. Data further indicate that regulation of C(sub)1 metabolism is also controlled by the sensor regulator, which prevents toxic levels of formaldehyde accumulating in the bacterium.

Results demonstrate that there is an obligatory nutritional relationship between methanotrophs and heterotrophs as well as metabolic interactions aiding the transformation of the complex linear alkylbenzenesulfonate molecule. Data further suggest that such interactions of the microbial populations favored adaptation to various environmental conditions as a community.

Results show that the sigma(sup)54-dependent Pu promoter activity of the TOL plasmid is stimulated by the alarmone ppGpp in Pseudomonas putida. Data also indicate that the stimulatory effect is moderate because of mild transcription activity of the alarmone.

Research has been conducted on the electrophilic addition of carbon dioxide to 2-lithio-1,3-dithiane-tetrahydrofuran-tetramethylethylendiamine. The mechanism of this addition and specific solvation effects have been investigated at the theoretical level.

Results show that in Pseudomonas sp. strain DP-4 the biodegradation of low level chemicals is influenced by the chemicals present at high concentration levels. Data indicate that the yield coefficient of 2,4-dichlorophenol is as an index of the extent of degradation.

The study shows that osmoregulation in cells of halophilic Tetragenococcus halophila bacterium is dependent on specific osmoprotectants and in their absence huge accumulation of sodium occurs. Data further point out that the salt concentration raises from 200 to 2,060 nanomoles per milligram of bacterial dry weight.

It is frequently stated that UV light would cause massive destruction of prebiotic organic compounds because of the absence of an ozone layer. The elevated UV flux of the early sun compounds this problem. This applies to organic compounds of both terrestrial and extraterrestrial origin. Attempts to deal with this problem generally involve atmospheric absorbers. We show here that prebiotic organic polymers as well as several inorganic compounds are sufficient to protect oceanic organic molecules from UV degradation. This aqueous protection is in addition to any atmospheric UV absorbers and should be a ubiquitous planetary phenomenon serving to increase the size of planetary habitable zones.

Cyanotriphenylborate (CTB) obstructs the recombinant alpha-subunit homooligomeric glycine receptor chloride channel with an inhibition rate of 50% with 50 microM glycine concentration. The alpha2 subunit homooligomers are unaffected by CTB. An interchange of the channel-lining transmembrane segment M2 of the alpha2 and alpha1 polypeptide helps transfer the CTB-resistivity of alpha2 subunit to alpha1 channels and reveals that the single 254 glycine residue of alpha1 subunit is essential for CTB sensitivity. CTB does not block the cation-selective nicotinic acetylcholine receptor channel.

The isolation and characterization of five new strains of mesophilic completely-oxidizing anaerobic sulfur-reducing bacteria capable of degrading a wide range of organic substrates were reported. All strains were gram-negative and grew by complete oxidation of organic compounds to CO2 and reduction of elemental sulfur to hydrogen sulfide. They were able to utilize acetate, propionate, lactate, pyruvate, succinate, oxaloacetate, maleinate, alanine, aspartate, glutamate and yeast extract.

Feeding deterrent effects of polyphenolic compounds from both terrestrial and marine environments have been well studied. However, the effects of this compound class on herbivore digestion and assimilation are less well known, particularly with respect to marine herbivores. This study found that the reduction of assimilation efficiency in Xiphister mucosus, a marine herbivorous fish, fed algae treated with marine polyphenolics (phlorotannins) was affected by phlorotannin molecular size (mass). In general, phlorotannins > 16.60 x 10 to the -21 (=>10 kDa) significantly decreased the assimilation of X. mucosus; those < 8.30 x 10 to the -21 (= 16.60 x 10 to the -21 g size range. Thus, the size range of phlorotannins that significantly reduced assimilation was also the size range in which they were most concentrated. This work supports the idea that polyphenolics as a chemical class do not all have the same bioactivity, but differ in their activity in a size-dependent manner. It also addresses some of the discrepancies seen in feeding-preference studies, providing an alternative explanation for results.

Ruminants take in considerable amounts of nitrogen in the form of ammonia, which is absorbed and converted to urea in the liver. Rising nitrogen intake causes an increase in both ammonia and urea production. This is associated with an increase in the liver clearance of amino acids. The cause of this association is undetermined, but the utilization of aspartate or glutamate in ureagenesis and its connection to other liver functions are implicated. Amino acids are also potential sources of carbon for glucose synthesis, therefore, gluconeogenesis may also contribute to the amino acid clearance rate of the liver.

Research has been conducted on the propargylic alcohols used as intermediates for the organic compound syntheses. The unexpected dimerization reactions of the 1,3-diarylpropargylic alcohol promoted by the Lewis acid have been investigated and the results are reported.

Research has been conducted on the cavitand phenol bowls, the derivatives of the resorcinarenes with enforced cavities binding organic compounds. Results indicate that the functionalized cavitand derivatives serve as building blocks for the novel host molecule synthesis.

This article describes metabolic engineering in Escherichia coli to introduce precursor pathways, such as the erythromycin precursor polyketide 6-deoxyerythronolide B, for the production of polyketides. The engineered E. coli produces methylmalonyl-CoA by the methylmalonyl-CoA mutase pathway and contains plasmids expressing 6-deoxyerytronolide B synthase. The 6-deoxyerythronolide B is generated from propionyl-CoA starter unit and (25)-methylmalonyl-CoA extender units.

Net ecosystem production (NEP) rates of dissolved organic carbon (DOC) are estimated in a coastal upwelling system. The study site is a large coastal inlet (2.76 [km.sup.3]) in the northern boundary (42-43 [degrees] N) of the eastern North Atlantic upwelling system. The two-dimensional circulation pattern in the system is governed by an offshore Ekman transport quite variable in magnitude and direction. A mass balance of the short-timescale (2-4 d) changes in measured DOC profiles is performed to obtain the NEP rates. Microbial oxidation of imported labile DOC (8% of total DOC, recycling time [Tau] [is less than] 5 d) at a maximum net rate of -37 mmol C [m.sup.-2] [d.sup.-1] occurred during a downwelling episode in the middle of the highly productive spring period. On the contrary, extensive export of labile DOC ([is less than] 15% of total DOC, [Tau] [is less than] 7 days) produced at net rates [is greater than] 42 mmol C [m.sup.-2] [d.sup.-1] took place during an upwelling episode in July, the middle of the upwelling season. This rate represents ~20% of the net primary production, demonstrating in the field the relative importance of horizontal offshore transport of labile DOC to the export of new production in upwelling systems. An autumn wind relaxation period results in dramatic changes in DOC standing stocks ([+ or -] 9/[micro]mol C [L.sup.-1]) caused by a conspicuous time segregation between sustained net phytoplankton production of labile DOC (+ 15 mmol C [m.sup.-2] [d.sup.-1], 11 d) and subsequent rapid bacterial degradation (-63 mmol C [m.sup.-2] [d.sup.-1], 3 d). Net horizontal export during this period was prevented by reduced offshore Ekman transport values, indicating that net DOC production is not always synonymous with net export. Finally, during the winter period, the large wind-driven net DOC horizontal exchange rates affected mainly the DOC standing stocks of no bioreactive materials in the system, whereas bacterial oxidation rates during this period reduced to less than -0.14 mmol C [m.sup.-2] [d.sup.-1].