The first occurrence in nature of two compounds from hops

Two compounds, (p-methoxyphenyl) diphenylmethanol (1) and tribenzylamine (2), were isolated from Humulus lupulus. Their structures were established on the basis of spectral evidence (MS, IR, NMR, HMBC, HMQC, 1H-1H COSY experiments). Compounds 1 and 2 were found as natural products at the first time.     

The first isolation of Borrelia burgdorferi sensu stricto in Russia

18 Borrelia isolates obtained from adult ticks of the Ixodes ricinus species, collected from different plants in April 2000 in the Khostinsk region of the Krasnodar Territory in the vicinity of the health resort of Matsesta not far from Sochi, were identified by means of PCR and the analysis of polymorphism of the restriction fragments of ribosomal rrf-rrl spacer amplicon. Among them, in addition to Borrelia species, found in Russia earlier (B. garinii, B. afzelii, B. valaisiana and B. lusitaniae), the classical causative agent of Lyme borreliosis (B. burgdorferi sensu stricto) was detected for the first time. The isolated strain (lr-4721) is now kept in the collection of the Borreliosis Center of the Ministry of Health of Russia (the Laboratory of Infections Vectors at the Gamaleya Research Institute of Epidemiology and Microbiology). The probable role of this infective agent in infectious pathology in Russia is discussed.     

Novel isolation of stilbenoids with enantiomeric and meso forms from a cyperus rhizome

Three stereoisomeric stilbene trimers bearing an (E)-2,3,5,6-tetraphenyl-4-styryl-2,3,5,6-tetrahydrobenzo[1,2-b:5,4-b′]difuran skeleton, (+)- and (?)-(E)-cyperusphenol A (1, 2) and (E)-mesocyperusphenol A (3), were isolated from a cyperus rhizome. Moreover, the geometrical isomers (4–6) were identified as the artifacts of their (E)-forms (1–3). The isolated products are the first instance of the co-occurrence of racemates (1, 2: new compounds) and a meso isomer (3), which resembles the C₂ symmetrical structure of an oligostilbenoid. These structures were characterized by NMR and CD spectroscopy. This is the first report that shows the occurrence of a racemate of a stilbenoid in the same plant material and the achievement of the optical separation of stilbene oligomers.     

The nature of interactions that contribute to postzygotic reproductive isolation in hybrid copepods

Deleterious interactions within the genome of hybrids can lower fitness and result in postzygotic reproductive isolation. Understanding the genetic basis of these deleterious interactions, known as Dobzhansky-Muller incompatibilities, is the subject of intense current study that seeks to elucidate the nature of these deleterious interactions. Hybrids from crosses of individuals from genetically divergent populations of the intertidal copepod Tigriopus californicus provide a useful model in which to study Dobzhansky-Muller incompatibilities. Studies of the basis of postzygotic reproductive isolation in this species have revealed a number of patterns. First, there is evidence for a breakdown in genomic coadaptation between mtDNA-encoded and nuclear-encoded proteins that can result in a reduction in hybrid fitness in some crosses. It appears from studies of the individual genes involved in these interactions that although this coadaptation could lead to asymmetries between crosses, patterns of genotypic viabilities are not often consistent with simple models of genomic coadaptation. Second, there is a large impact of environmental factors on these deleterious interactions suggesting that they are not strictly intrinsic in nature. Temperature in particular appears to play an important role in determining the nature of these interactions. Finally, deleterious interactions in these hybrid copepods appear to be complex in terms of the number of genetic factors that interact to lead to reductions in hybrid fitness. This complexity may stem from three or more factors that all interact to cause a single incompatibility or the same factor interacting with multiple other factors independently leading to multiple incompatibilities.     

The first isolation of Nocardia veterana from a human mycetoma

The clinical isolates from biopsy specimen human subcutaneous nodule developed orange-colored and wrinkled colonies on Sabouraud's dextrose agar at 24 C for 2 weeks. The isolates were aerobic and gram-positive. The bacteria were rod-shaped to coccoid and 1 x 5 microm in size. The assimilation tests revealed that the clinical isolate was identical to a reference strain of Nocardia veterana. A nucleotide sequence analysis of the 16S ribosomal DNA from the isolate and a reference strain of N. veterana showed 99.8% similarity. All data are consistent with the conclusion that the isolate in this human case of mycetoma is N. veterana.     

Novel isolation of resveratrol dimer O-glucosides with enantiomeric aglycones from the leaves of Shorea cordifolia

Two O-glucosides of resveratrol dimers, ampelopsin F-11b-O-β-glucopyranosides with enantiomeric aglycones [cordifoloside A (1) and cordifoloside B (2)] and an enantiomer of the aglycone [(?)-ampelopsin F] were isolated from the leaves of Shorea cordifolia (Dipterocarpaceae). These structures were identified on the basis of spectroscopic evidence and their absolute configurations were elucidated using circular dichroism data. This is the first report on oligostilbenoids that demonstrates the co-occurrence of diastereomeric O-glucosides with enantiomeric aglycones in this family.     

The genotoxicity of enantiomeric aliphatic epoxides

The (R)- and (S)-optical isomers of 9 epoxides, benzyloxymethyloxirane, epichlorohydrin, glycidol, glycidyl 3-nitrobenzenesulfonate, glycidyl 4-nitrobenzoate, glycidyl tosylate, styrene oxide, glycidyl 1-naphthyl ether and glycidyl 4-nitrophenyl ether, have been compared for their in vivo and in vitro genotoxicity. The in vitro short-term test employed was the Ames mutagenicity assay with Salmonella strain TA100. The in vivo tests were chromosomal aberrations (CA) as well as sister-chromatid exchange (SCE) in bone-marrow cells of mice following intraperitoneal administration of these epoxides. Differences in mutagenicity between isomers were established with TA100 for all the compounds. While 13 of the isomers were genotoxic compared to a negative control by CA measurements, only in the case of glycidyl 4-nitrobenzoate could a significant difference be found between isomers by this test. However, with SCE evaluations, differences were detected between the (R)- and (S)-isomers for all the pairs of compounds with the exception of those for benzyloxymethyloxirane and glycidyl 4-nitrophenyl ether. At least in part, differences in the patterns of genotoxicity among compounds can be related to their differences in reaction pathways.     

The first isolation of a cyanophage-Synechococcus system from the East China Sea

A cyanophage strain and its host Synechococcus were isolated from the East China Sea. The host Synechococcus sp. SJ01 was characterized by its 16S rRNA, ITS, and psbA gene sequences as well as by its morphological appearance and pigmentation. The cyanophage, strain S-SJ2, was able to cause a lytic infection of the coastal Synechococcus. TEM of negative-stained specimens showed that the phage isolate has an isometric head with a diameter of 68 nm and a long tail with a length of 280 nm. The cyanophage-Synechococcus system from the East China Sea shares many properties with other marine cyanophage-Synechococcus systems worldwide.     

Comparison of methods for isolation of dematiaceous fungi from nature

Direct plating and animal inoculation techniques were compared for effectiveness in isolating dematiaceous fungi from nature. The direct plating technique involved comparison of aqueous and mineral oil extraction of the samples with subsequent plating on Mycobiotic and Sabhi agar. Twenty four different organisms were recovered from 19 samples using both extraction procedures and both media. Dematiaceous fungi isolated by direct plating were Alternaria alternata, Cladosporium spp., Exophiala jeanselmei, Wangiella dermatitidis and 6 unidentified organisms. Direct plating resulted in more isolations of dematiaceous fungi partly because of the frequent isolations of A. alternata and W. dermatitidis. Both more and a larger variety of organisms were recovered on Mycobiotic than on Sabhi agar. The aqueous extraction of samples resulted in more direct plating isolations of fungi than oil extraction.Only dematiaceous fungi were isolated with the animal inoculation techniques. Fungi isolated from hamsters included Cladosporium spp., Exophiala spinifera, Phialophora verrucosa, Rhinocladiella sp. and 3 unidentified organisms. Fungi isolated by the mouse inoculation technique included Bispora betulina, Cladosporium spp., W. dermatitidis and 1 unidentified organism. In general there was variation in the types of organisms isolated from the same samples depending on the isolation procedure used.     

The nature of siliceous mosaics forming the first shell of the brachiopod Discinisca

The juvenile shell of the brachiopod Discinisca consists of a mosaic of micrometer-sized siliceous tablets embedded in a chitinous substrate. The first-formed tablets are secreted on glycocalyx by a newly differentiated collective of outer epithelial cells. They are mainly rhombic but may also be ellipsoidal, discoidal, or deformed and sporadically overlap one another. On the surrounding juvenile shell, secreted by an incipient outer mantle lobe, the tablets are nearly all perfect rhombic plates in rhombic arrays. Their constant size, arrangement, and centripetal crystallization suggest intracellular assembly. The tablets, which are normally bilamellar, consist of discrete aggregates of crystalline spherules of silica in rhombic arrays within an organic matrix of fibrous protein and, presumably, a soluble polysaccharide(s). Mosaic secretion ceases at about the time when juveniles settle on the sea bed, which more or less coincides with the secretion of a ring of lamellae around the mosaic, induced by rapid advances and retractions of the outer mantle lobe prior to deposition of the organophosphatic mature shell. Energy dispersion X-ray analyses of pelagic and newly settled juveniles show that phosphatic secretion, even in the site of the first-formed outer epithelial collective, does not begin until all siliceous secretion has ceased.     

The first isolation of two types of trifluoroleucine resistant mutants of Saccharomyces servazzii

Saccharomyces servazzii plays a crucial role in the making of Japanese radish pickles. To make more flavorsome pickles, we sought to generate trifluoroleucine-resistant mutants of S. servazzii. The three resulting mutants could be classified into two types: one that produces more isoamyl alcohol than the parental strain, and one that produces less. The first type has been well documented in Saccharomyces cerevisiae but the latter appears to be novel and has been characterized as such.     

Glycopentaphyllone: The first isolation of hydroperoxyquinolone from the fruits of Glycosmis pentaphylla

A new hydroperoxyquinolone alkaloid, glycopentaphyllone (1), along with nine compounds (2–10), was isolated from the fruits of Glycosmis pentaphylla. Their structures were elucidated on the basis of spectroscopic methods. The absolute configuration of glycopentaphyllone at C-2′ was established as S-configuration by applying Mosher's method. In addition, the completed assignments of ¹³C NMR as well as 2D NMR spectral data of compound 5 were reported herein for the first time. Also, all isolates were evaluated for antibacterial activity against Escherichia coli TISTR 780, Salmonella typhimurium TISTR 292, Staphylococcus aureus TISTR 1466, and Methicillin-resistant S. aureus SK1.     

The correlation of sweetness and bitterness of enantiomeric aminoacids

A correlation discovered between the sweetness of $\text{D}$ and the bitterness of $\text{L}$-aminoacids suggests the possible existence of corresponding taste receptors with enantiomeric active sites. They offer possible explanations for the reported taste characteristics of various other substances ($\text{L}$-aspartic acid amides, quinine, perillartine, etc.).