323 research outputs found
Distinguishing the parasitic wasp, Peristenus howardi, from some of its congeners using polymerase chain reaction and restriction endonuclease digestion
A molecular procedure incorporating polymerase chain reaction (PCR) of the COI gene and restriction endonuclease digestion of PCR products was used to distinguish Peristenus howardi (Hymenoptera: Braconidae) from four other Peristenus species. Non-solvent extraction of parasite DNA using a commercially available kit proved to be very effective in producing amplifiable template. Use of SfcI endonuclease produced restriction fragments with banding patterns in agarose gel electrophoresis that readily separated P. howardi, P. digoneutis, P. conradi, P. pallipes, and P. pseudopallipes. However, while the restriction fragment banding patterns of both P. pallipes and P. pseudopallipes were easily distinguishable from the other Peristenus species, they could not be reliably separated from one another. This molecular procedure can be used in applied and ecological research to better understand the role of P. howardi in the Peristenus-Lygus parasite-host system within the Pacific Northwest. Consensus sequences of our amplimers for all five Peristenus spp. are deposited in GenBank under accession numbers AY626370, AY626371, AY626372, AY626373, and AY626374
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Genomes, expression profiles, and diversity of mitochondria of the White-footed Deermouse Peromyscus leucopus, reservoir of Lyme disease and other zoonoses.
The cricetine rodents Peromyscus leucopus and P. maniculatus are key reservoirs for several zoonotic diseases in North America. We determined the complete circular mitochondrial genome sequences of representatives of 3 different stock colonies of P. leucopus, one stock colony of P. maniculatus and two wild populations of P. leucopus. The genomes were syntenic with that of the murids Mus musculus and Rattus norvegicus. Phylogenetic analysis confirmed that these two Peromyscus species are sister taxa in a clade with P. polionotus and also uncovered a distinction between P. leucopus populations in the eastern and the central United States. In one P. leucopus lineage four extended regions of mitochondrial pseudogenes were identified in the nuclear genome. RNA-seq analysis revealed transcription of the entire genome and differences from controls in the expression profiles of mitochondrial genes in the blood, but not in liver or brain, of animals infected with the zoonotic pathogen Borrelia hermsii. PCR and sequencing of the D-loop of the mitochondrion identified 32 different haplotypes among 118 wild P. leucopus at a Connecticut field site. These findings help to further establish P. leucopus as a model organism for studies of emerging infectious diseases, ecology, and in other disciplines
Determination of the Relative and Absolute Configurations of the Female-produced Sex Pheromone of the Cerambycid Beetle Prionus californicus
We previously identified the basic structure of the female-produced sex attractant pheromone of the cerambycid beetle, Prionus californicus Motschulsky (Cerambycidae: Prioninae), as 3,5-dimethyldodecanoic acid. A synthesized mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid was highly attractive to male beetles. Here, we describe stereoselective syntheses of three of the four possible stereoisomers, and the results of laboratory and field bioassays showing that male beetles are attracted specifically to (3R,5S)-3,5-dimethyldodecanoic acid, but not to its enantiomer, (3S,5R)-3,5-dimethyldodecanoic acid, indicating that the (3R,5S)-enantiomer is the active pheromone component. The diastereomeric (3R,5R)- and (3S,5S)-enantiomers were excluded from consideration because their gas chromatographic retention times were different from that of the insect-produced compound. The mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid was as attractive to male P. californicus as the (3R,5S)-enantiomer, indicating that none of the other three stereoisomers inhibited responses to the active enantiomer. Beetles responded to as little as 10 ng and 10 μg of synthetic 3,5-dimethyldodecanoic acid in laboratory and field studies, respectively. Field studies indicated that capture rate did not increase with dosages of 3,5-dimethyldodecanoic acid greater than 100 μg. In field bioassays, males of a congeneric species, P. lecontei Lameere, were captured in southern California but not in Idaho
Absolute Present, Zen and Schrödinger’s One Mind
Erwin Schrödinger holds a prominent place in the history of science primarily due to his crucial role in the development of quantum physics. What is perhaps lesser known are his insights into subject-object duality, consciousness and mind. He documented himself that these were influenced by the Upanishads, a collection of ancient Hindu spiritual texts. Central to his thoughts in this area is that Mind is only One and there is no separation between subject and object. This chapter aims to bridge Schrödinger’s view on One Mind with the teachings of Dōgen, a twelfth century Zen master. This bridge is formed by addressing the question of how time relates to One Mind, and subject-object duality. Schrödinger describes the experience of One Mind to be like a timeless now, whereas subject-object duality involves a linear continuum of time. We show how these differing positions are unified in the notion of ‘absolute present’, which was put forward in the philosophy of Nishida Kitarō (1871–1945). In addition, we argue that it is in this notion of absolute present that the views of Schrödinger, Dōgen and Nishida meet
Nondestructive Evaluation of Standing Trees With a Stress Wave Method
The primary objective of this study was to investigate the usefulness of a stress wave technique for evaluating wood strength and stiffness of young-growth western hemlock and Sitka spruce in standing trees. A secondary objective was to determine if the effects of silvicultural practices on wood quality can be identified using this technique. Stress wave measurements were conducted on 168 young-growth western hemlock and Sitka spruce trees. After in situ measurements, a 0.61-m-long bole section in the test span was taken from 56 felled trees to obtain small, clear wood specimens. Stress wave and static bending tests were then performed on these specimens to determine strength and stiffness. Results of this study indicate that in situ stress wave measurements could provide relatively accurate and reliable information that would enable nondestructive evaluation of wood properties in standing trees. The mean values of stress wave speed and dynamic modulus of elasticity for trees agreed with those determined from small, clear wood specimens. Statistical regression analyses revealed good correlations between stress wave properties of trees and static bending properties of small, clear wood specimens obtained from the trees. Regression models showed statistical significance at the 0.01 confidence level. Results of this study also demonstrate that the effect of silvicultural practices on wood properties can be identified with the stress wave properties of trees. This indicates that this nondestructive stress wave technique can be used to track property changes in trees and help determine how forests could be managed to meet desired wood and fiber qualities
Poly[[tetrakis(μ2-pyrazine N,N′-dioxide-κ2 O:O′)holmium(III)] tris(perchlorate)]
The title three-dimensional coordination network, {[Ho(C4H4N2O2)4](ClO4)3}n, is isostructural to that of other lanthanides. The Ho+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square anti-prismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001) (110) and interact with the coordination network through C—H⋯O hydrogen bonds
Poly(alkyl methacrylate) tooth coatings for dental care: evaluation of the demineralisation-protection benefit using a time-resolved in vitro method
An in vitro method for the time-resolved quantification of acid-mediated tooth demineralisation has been developed and evaluated against putative non-permanent protective formulations based on a series of poly(alkyl methacrylate)s. Using a thermostatted carousel, dentally relevant substrates consisting of hydroxyapatite discs or sections of bovine teeth have been exposed to aqueous citric acid under controlled conditions, before and after being treated with the polymeric coatings. The dissolution of phosphate was monitored by the determination of 31P by Inductively Coupled Plasma—Mass Spectrometry and by the spectrophotometric phosphovanadomolybdate method. Dose-response plots constructed for both groups of treated substrates have revealed that the coatings significantly reduce erosion rates but are less effective at inhibiting tooth demineralisation than the standard fluoride treatment. The approach has enabled an evaluation of the erosion-protection efficiency of each coating
Poly[[tetrakis(μ2-pyrazine N,N′-dioxide-κ2 O:O′)erbium(III)] tris(perchlorate)]
The title three-dimensional coordination network, {[Er(C4H4N2O2)4](ClO4)3}n, is isostructural to that of other lanthanides. The Er+3 cation lies on a fourfold roto-inversion axis. It is coordinated in a distorted square-antiprismatic fashion by eight O atoms from bridging pyrazine N,N′-dioxide ligands. There are two unique pyrazine N,N′-dioxide ligands. One ring is located around an inversion center, and there is a a twofold rotation axis at the center of the other ring. There are also two unique perchlorate anions. One is centered on a twofold rotation axis and the other on a fourfold roto-inversion axis. The perchlorate anions are located in channels that run perpendicular to (001) and (110) and interact with the coordination network through C—H⋯O hydrogen bonds
Il monastero benedettino di S. Giorgio in Braida a Verona: nuove prospettive di ricerca sulla rifabbrica romanica (sec. XII)
L’attuale aspetto rinascimentale della chiesa di San Giorgio in Braida è frutto di una serie di interventi promossi dai canonici veneziani di San Giorgio in Alga a partire dalla fine del XV secolo. Il monastero benedettino, tuttavia, fu fondato nella metà dell’XI secolo e completamente ricostruito fra il terzo e il quarto decennio del secolo successivo per volere del vescovo Bernardo. L’articolo ripercorre le vicende storiche dell’istituzione in età medievale e rende nota l’esistenza di alcune parti della compagine romanica tuttora inedite, che permettono d’inserire il cantiere di San Giorgio in Braida nel contesto delle coeve manifestazioni architettoniche veronesi
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