Discrimination of sunflower volatiles by the red sunflower seed weevil

Five principle monoterpenoid and other constituent volatile chemicals of sunflower heads were combined to resemble two lines of sunflower (Helianthus annuus L.): one U.S.D.A. standard line and one French line which was poorly visited by insects (Etievant et al., 1984). Field trials of attraction to red sunflower seed weevils (Smicronyx fulvus Le Conte, Coleoptera: Curculionidae) showed that one was clearly preferred over the other. The more attractive mixture contained -pinene, -pinene, limonene, camphene and bornyl acetate in a ratio resembling that of Flath et al. (1985) rather than that described by Etievant et al. (1984). One or two volatiles were deleted from the optimal blend but only mixtures of five volatiles showed the highest attraction. Substitution of sabinene, another volatile prominent in sunflower, for one of the five in the optimal blend also decreased attraction of seed weevils. When the monoterpenoid components and green leaf volatiles in the traps resembled the ratios of most of the prominent volatiles of sunflower, attraction was significantly greater than controls.     

Solid-Phase Products of Bacterial Oxidation of Arsenical Pyrite

Bacterial leaching of an As-containing pyrite concentrate produced acidic (pH < 1) leachates. During the leaching, the bacteria solubilized both As and Fe, and these two elements were distributed in solution-phase and solid-phase products. Jarosite and scorodite were the exclusive crystalline products in precipitate samples from the bacterial leaching of the sulfide concentrate.     

A cluster of fourteen genes from enteropathogenic Escherichia coli is sufficient for the biogenesis of a type IV pilus

Enteropathogenic Escherichia coli (EPEC) adhere to epithelial cells in microcolonies, a pattern termed localized adherence (LA). LA is dependent upon the presence of 50–70MDa plasmids, termed EPEC adherence factor (EAF) plasmids. Expression of an EAF plasm id-encoded type IV fimbria, the bundle-forming pilus (BFP), is associated with the LA phenotype. TnphoA insertions in bfpA, the gene encoding the major structural subunit of the BFP, abolish LA. While bfpA::TnphoA mutants cannot be complemented for LA by plasmids carrying the bfpA gene alone in trans, this work shows that they can be complemented by plasmids carrying the bfpA gene, as well as approximately 10kb of downstream sequence, suggesting that such mutations have polar effects on downstream genes. The identification and characterization of a cluster of 13 genes immediately downstream of bfpA are described. The introduction into a laboratory Escherichia coli strain of a plasmid containing these 14 bfp gene cluster genes, along with pJPN14, a plasmid containing another fragment derived from the EAF plasmid, confers LA ability and BFP biogenesis. However, when a mutation is introduced into the last gene of the bfp cluster, neither LA nor BFP biogenesis is conferred. This work also provides evidence to show that the fragment cloned in pJPN14 encodes a factor(s) which results in increased levels of the pilin protein. Finally, it is shown that expression of the 14 genes in the bfp cluster from an IPTG-inducible promoter, in the absence of pJPN14, is sufficient to reconstitute BFP biogenesis in a laboratory E. cob strain, but is insufficient for LA. This is the first report demonstrating the reconstitution of a type IV pilus in a laboratory E. coli strain with a defined set of genes. The 8FP system should prove to be a useful model for studying the molecular mechanisms of type IV pilus biogenesis.     

Susceptibility of Campylobacter jejuni and Yersinia enterocolitica to UV radiation

Two enteric pathogens, Campylobacter jejuni and Yersinia enterocolitica serogroup O:3, together with Escherichia coli, were investigated for susceptibility to UV radiation at 254 nm. The UV dose required for a 3-log reduction (99.9% inactivation) of C. jejuni, Y. enterocolitica, and E. coli was 1.8, 2.7, and 5.0 mWs/cm2, respectively. Using E. coli as the basis for comparison, it appears that C. jejuni and Y. enterocolitica serogroup O:3 are more sensitive to UV than many of the pathogens associated with waterborne disease outbreaks and can be easily inactivated in most commercially available UV reactors. No association was found between the sensitivity of Y. enterocolitica to UV and the presence of a 40- to 50-megadalton virulence plasmid.     

Conditioning of skin conductance levels through a combined instrumental-classical conditioning procedure

A paucity of studies and inconsistent results characterize attempts to instrumentally condition tonic electrodermal activity. The present study was conducted to further explore the classical and instrumental conditioning of skin conductance levels (SCLs) through auditory analogue feedback. Fifty undergraduates were randomly assigned to one of five groups of equal size: instrumental conditioning alone, classical conditioning alone, instrumental and classical conditioning combined, and two control groups. The combined training group achieved significantly higher SCLs relative to the group receiving instrumental conditioning alone.     

Chromatographic analysis of isoflavonoid accumulation in stressed Pisum sativum

High-performance liquid chromatography has been used to study isoflavonoid accumulation in copper(II) chloride stressed Pisum sativum. Liquiritigenin, isoliquiritigenin, formononetin, pseudobaptigenin, afrormosin and anhydropisatin have been identified in addition to the pterocarpan phytoalexin pisatin. The relationships of these metabolites to isoflavonoid biosynthesis and stress response in pea are discussed.     

Development and validation of genetic markers for sex and cannabinoid chemotype in Cannabis sativa L.

Hemp (Cannabis sativa L.) is an emerging dioecious crop grown primarily for grain, fiber, and cannabinoids. There is good evidence for medicinal benefits of the most abundant cannabinoid in hemp, cannabidiol (CBD). For CBD production, female plants producing CBD but not tetrahydrocannabinol (THC) are desired. We developed and validated high‐throughput PACE (PCR Allele Competitive Extension) assays for C. sativa plant sex and cannabinoid chemotype. The sex assay was validated across a wide range of germplasm and resolved male plants from female and monoecious plants. The cannabinoid chemotype assay revealed segregation in hemp populations, and resolved plants producing predominantly THC, predominantly CBD, and roughly equal amounts of THC and CBD. Cultivar populations that were thought to be stabilized for CBD production were found to be segregating phenotypically and genotypically. Many plants predominantly producing CBD accumulated more than the current US legal limit of 0.3% THC by dry weight. These assays and data provide potentially useful tools for breeding and early selection of hemp.     

Best environmental predictors of breeding phenology differ with elevation in a common woodland bird species

Temperatures in mountain areas are increasing at a higher rate than the Northern Hemisphere land average, but how fauna may respond, in particular in terms of phenology, remains poorly understood. The aim of this study was to assess how elevation could modify the relationships between climate variability (air temperature and snow melt‐out date), the timing of plant phenology and egg‐laying date of the coal tit (Periparus ater). We collected 9 years (2011–2019) of data on egg‐laying date, spring air temperature, snow melt‐out date, and larch budburst date at two elevations (~1,300 m and ~1,900 m asl) on a slope located in the Mont‐Blanc Massif in the French Alps. We found that at low elevation, larch budburst date had a direct influence on egg‐laying date, while at high‐altitude snow melt‐out date was the limiting factor. At both elevations, air temperature had a similar effect on egg‐laying date, but was a poorer predictor than larch budburst or snowmelt date. Our results shed light on proximate drivers of breeding phenology responses to interannual climate variability in mountain areas and suggest that factors directly influencing species phenology vary at different elevations. Predicting the future responses of species in a climate change context will require testing the transferability of models and accounting for nonstationary relationships between environmental predictors and the timing of phenological events.