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Lascivol was identified as the bitter compound in two Tricholoma species, T. aestuans and T. virgatum, and was previously isolated from the European mushroom T. lascivum. The structure of lascivol was previously solved by X-ray crystallographical analysis but its stereochemistry at C3 remained ambiguous. We thus re-examined the absolute configuration of C3 bearing a hydroxy group using the modified Mosher’s method.

Purpose A simple and high-throughput analytical method for determining clitidine in Paralepistopsis acromelalga using hydrophilic interaction liquid chromatography–tandem mass spectrometry (LC–MS/MS) was established. Methods To determine clitidine in the mushrooms, a simple procedure including dilution with methanol solution and filtering by cartridge was employed just before quantification by LC–MS/MS for high-throughput analysis. In this report, concentrations of clitidine in mushrooms were determined by the standard addition method. Results The present established method was successfully applied to the analysis of fruit bodies of P. acromelalga, which were obtained from five different locations in Japan. Results on concentrations of clitidine in each stem and cap of P. acromelalga specimens tested showed that their concentrations were quite different, not only between stems and caps, but also among locations and strains; the concentrations of clitidine in stems and caps ranged from 1.41 to 9.30 mg/g and 3.17 to 14.4 mg/g, respectively. Conclusions This is the first report to present a detailed quantitative analysis of clitidine by MS and the distribution of clitidine in stems and caps of P. acromelalga . This analytical method for clitidine was thought to be useful in P. acromelalga poisoning cases to identify the causative toxic mushroom.

We have isolated the small, highly strained carboxylic acid cycloprop-2-ene carboxylic acid from the Asian toxic mushroom Russula subnigricans . This compound is responsible for fatal rhabdomyolysis, a new type of mushroom poisoning that is indicated by an increase in serum creatine phosphokinase activity in mice. We found that polymerization of the compound at high concentrations via ene reaction abolishes its toxicity.

Steroidal saponins are widely distributed in many plant species. Their diverse structures have resulted in a wide range of applications, including drug and medicine production. It has been suggested that the nature of the non-saccharide and oligosaccharide portions of the saponin molecule both contribute to the properties of individual saponins. Despite numerous studies on the occurrence, chemical structure, and varying pharmaceutical activities of steroidal saponins, their biosynthesis pathway is poorly understood. Glycosylation is thought to be the final step in steroidal saponin biosynthesis and it is thought to be involved in regulating the biological activities of saponins. Isolation of the glycosyltransferases that catalyze the transfer of sugar molecules to steroidal compounds will help to clarify the mechanisms that produce diverse saponins and control their activities in plants. In this study, we obtained three cDNAs encoding putative glycosyltransferases from Solanum aculeatissimum. One of the three, SaGT4A showed UDP-glucosyltransferase activity. This is the first cloned glucosyltransferase involved in steroidal saponin biosynthesis. SaGT4A catalyzes the 3-O-glucosylation of steroidal sapogenins, such as diosgenin, nuatigenin, and tigogenin. This enzyme also glucosylates steroidal alkaloids, such as solanidine, solasodine, and tomatidine. Gene expression analysis revealed that the accumulation of SaGT4A transcripts showed a unique response to wounding stress indicating the involvement of SaGT4A in plant defense system.

Within a few minutes of perspiration, the colourless, viscous sweat of the hippopotamus gradually turns red, and then brown as the pigment polymerizes. Here we isolate and characterize the pigments responsible for this colour reaction. The unstable red and orange pigments turn out to be non-benzenoid aromatic compounds that are unexpectedly acidic and have antibiotic as well as sunscreen activity.

The red and orange pigments in this secretion account for its protective properties. Within a few minutes of perspiration, the colourless, viscous sweat of the hippopotamus gradually turns red, and then brown as the pigment polymerizes. Here we isolate and characterize the pigments responsible for this colour reaction. The unstable red and orange pigments turn out to be non-benzenoid aromatic compounds that are unexpectedly acidic and have antibiotic as well as sunscreen activity. Cool customer: hippos create their own antibiotic sunscreen. P. JOHNSON/CORBIS

Invasive species pose serious threats to global biodiversity, prompting studies to identify factors underlying invasion and establishment success. However, it's difficult to discern these factors due to the absence of survey data since the initial invasion, because introduced species often remain unnoticed until their population becomes large enough. Here, we investigated the establishment process of the alien zooplankton, Daphnia pulicaria , in the past 30 years using sedimentary archives at Lake Biwa. We performed genetic analysis on mitochondrial DNA sequences of the control region and ND5 gene of ephippia in sediments, as well as present females from water samples. Furthermore, we investigated the relationships between the abundance of D. pulicaria and its major predator fish, Ayu, based on the catch data, as well as its competitor, Daphnia galeata whose abundance was inferred from claw remains. Our analyses showed the studied mitochondrial sequences were identical between all samples. The abundance of D. pulicaria was not correlated with that of a competitor but was negatively with that of a predator. These findings suggest the successful establishment of D. pulicaria was primarily influenced by reduced predation pressure, with a limited impact from competitive interactions and potential hindrance for adaptation caused by loss of genetic variation.

According to quantum chromodynamics, vacuum is not an empty space, because it is filled with quark–antiquark pairs. The pair has the same quantum numbers as the vacuum and forms a condensate because the strong interaction of the quantum chromodynamics is too strong to leave the vacuum empty. This quark–antiquark condensation, the chiral condensate, breaks the chiral symmetry of the vacuum. The expectation value of the chiral condensate is an order parameter of the chiral symmetry, which is expected to decrease at high temperatures or high matter densities where the chiral symmetry is partially restored. Head-on collisions of nuclei at ultra-relativistic energies have explored the high-temperature regime, but experiments at high densities are rare. Here we measure the spectrum of pionic 121Sn atoms and study the interaction between the pion and the nucleus. We find that the expectation value of the chiral condensate is reduced at finite density compared to the value in vacuum. The reduction is linearly extrapolated to the nuclear saturation density and indicates that the chiral symmetry is partially restored due to the extremely high density of the nucleus.In quantum chromodynamics, the condensation of quark–antiquark pairs breaks the chiral symmetry of vacuum. Experiments with pionic tin atoms demonstrate that the symmetry is partially restored at high densities.

Background Intervention studies have shown that isoflavone treatment improved glucose metabolism, indicating that soy intake may have a potential role in diabetes prevention. Objectives We aimed to investigate the prospective association of soy isoflavone and soy food intakes with incidence of gestational diabetes mellitus (GDM) in a birth cohort study. Methods We recruited 97,454 pregnant women (median gestational age 12 weeks) between January 2011 and March 2014. Dietary intakes during the 12 months preceding study enrollment were assessed by a semi-quantitative food frequency questionnaire. The relative risks of GDM associated with soy isoflavone and soy food intakes were obtained by Poisson regression. Demographic information, histories of diseases, socioeconomic status, lifestyles, and dietary habits, obtained by a self-administrated questionnaire, were used for covariate adjustments. Results We identified 1904 cases of GDM (2.2%) among 84,948 women. Compared with those in the lowest quintile of soy isoflavone intake, women in the highest quintile were found to have experienced a significantly lower risk of GDM (multivariate relative risk = 0.82; 95% confidence interval: 0.70, 0.95; P for trend = 0.05). Similar results were observed for genistein and daidzein. Regarding soy foods, intakes of miso soup and natto were inversely associated with GDM incidence (both P for trend ≤ 0.01), whereas the association for tofu intake appeared to be nonlinear ( P for trend = 0.74). Conclusions Higher intakes of miso soup and natto before and during early pregnancy, compared with lower intakes, may be associated with a lower incidence of GDM.