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Original Observation (original + observation)
Selected AbstractsThe use of muscle protein for egg production in the Zebra Finch Taeniopygia guttataIBIS, Issue 2 2002Mat Cottam Pectoral muscle can be an important source of protein for birds. During egg formation Zebra Finches Taeniopygia guttata are able to compensate for nutritional inadequacies in their diet by utilization of the protein in their flight muscles. This analysis of flight muscle sarcoplasm supported earlier observations of protein depletion during egg production. However, SDS gel electrophoresis of the sarcoplasm produced no evidence to support a previous suggestion of the existence of a high molecular weight storage protein, and it is thought that the original observation may have arisen as an artefact of experimental methodology. During laying, protein removal from the sarcoplasm occurred over a range of different proteins and was not confined to any one specific protein band. Additionally, the protein band most reduced over the course of laying did not contain elevated levels of the amino acids most limiting to egg production. These results indicate that during laying, flight muscle sarcoplasm contributes towards the nutrient requirements of egg production from general protein reserves, rather than from a specific storage protein containing elevated levels of limiting amino acids. [source] Is the (E)- , -farnesene only volatile terpenoid in aphids?JOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2005F. Francis Abstract:, Herbivore insects use a broad range of chemical cues to locate their host to feed or to oviposit. Whether several plant volatiles are effective allelochemicals for insects, the latter also emit molecules which have infochemical role. The (E)- , -farnesene (EBF) is a well-known aphid alarm pheromone commonly found in all previously tested species. Analysis of the released molecules from 23 aphid species, mainly collected on their natural host plant from May to July, was performed by gas chromatography,mass spectrometry. While EBF was identified as the main volatile substance in 16 species, alone or associated with other molecules, the alarm pheromone was only a minor component of the volatile molecule pattern of five other species. Moreover, two species, Euceraphis punctipennis and Drepanosiphum platanoides, did not release EBF at all but other terpenes were identified. This original observation raised the question on the utility and the source of the non-EBF volatiles. Are these potential infochemical substances produced by the aphid or only absorbed from the host plant? Here we determined that terpenes released by insects were not only provided by the host plants. Indeed, Megoura viciae emitted additional molecules than the ones from several aphid species reared on the same host plant. Moreover, no systematic relation between the feeding behaviour of the aphid species and the volatile releases was observed. Aphid terpene composition and proportion would provide reliable cues to identify the emitting organism, plant or insect. The next step of this work will be to determine the infochemical role of terpenes found in the range of tested aphid samples to better understand the relations between the different tritrophic levels. [source] PHYLOGENY OF AULACOSEIRA (BACILLARIOPHYTA) BASED ON MOLECULES AND MORPHOLOGY,JOURNAL OF PHYCOLOGY, Issue 4 2004Stacy M. Edgar The phylogeny of 67 populations representing 45 species of Aulacoseira Thwaites was estimated by maximum parsimony methods using a combination of nucleotide sequence data and qualitative and quantitative morphological characteristics of the silica cell wall gathered primarily from original observation by LM and SEM. A new type of character using continuous quantitative variables that describe the ontogenetic-allometric trajectories of cell wall characteristics over the life cycle (size range) of diatoms is introduced. In addition to the 45 Aulacoseira species, the phylogeny also incorporated one Miosira Krammer, Lange-Bertalot, and Schiller species and two outgroup species (Melosira varians Agardh and Stephanopyxis nipponica Gran & Yendo). Fifteen species, represented by 24 populations, also contained molecular data from the nuclear genome (18S rDNA), and 11 of these species (18 populations) contained data from the chloroplast genome (rbcL) as well, which were sequenced or downloaded from GenBank. The phylogeny of Aulacoseira is composed of five major clades: 1) an A. crenulata (Ehrenburg) Thwaites and A. italica (Ehrenburg) Simonsen clade, which is the most basal; 2) an A. granulata (Ehrenburg) Simonsen complex clade; 3) an A. ambigua (Grunow) Simonsen clade; 4) an A. subarctica (O. Müller) Haworth and A. distans (Ehrenburg) Simonsen clade; and 5) an A. islandica (O. Müller) Simonsen clade that also contained endemic species from Lake Baikal, Siberia and many extinct Aulacoseira taxa. Monophyly of Aulacoseira can only be achieved if Miosira is no longer given separate generic status. [source] Systematics of Chaetocerotaceae (Bacillariophyceae).PHYCOLOGICAL RESEARCH, Issue 2 2003SUMMARY In order to construct a model of evolutionary relationships within the diatom family Chaetocerotaceae, 37 species of Chaetoceros Ehrenberg, representing all subgenera and 21 of 22 subgeneric sections of the genus, plus three Bacteriastrum Shadbolt species, representing both of its subgeneric sections, were subjected to cladistic analysis. One species each of Eucampia Ehrenberg, Cerataulina Peragallo, Hemiau-lus Ehrenberg, Attheya West and Gonioceros H. & M. Peragallo were used as outgroups. A matrix of 65 binary and multistate morphological characters was constructed, with data being gathered from original observation of material in the light and electron microscopes, and from the published literature. The analysis yielded 36 most-parsimonious cladograms of 316 steps; incongruence between trees is largely restricted to some taxa representing undersampled sections of Chaetoceros subg. Hyalochaete. The robustness of this hypothesis was examined in several ways. To assess the effect of character weighting, the bootstrap was used to randomly weight characters. The parsimony criterion was relaxed via a decay index, and finally, the tree length was compared to that of trees randomly generated from the data matrix. The majority of investigated species of Chaetoceros subg. Phaeoceros, Chaetoceros subg. Hyalochaete and Bacteriastrum appear to belong to a continuous grade, rather than comprising individual clades. Chaetoceros is paraphyletic. Thus, the traditional classification does not accurately reflect the hypothesized phylogenetic relationships of this family. [source] The petrosquamosal sinus in humansJOURNAL OF ANATOMY, Issue 6 2006Diego San Millán Ruíz Abstract This article provides a comprehensive description of the morphology of the human petrosquamosal sinus (PSS) derived from original observations made on 13 corrosion casts of the cranial venous system combined with routine clinical imaging studies in two patients. The PSS is not a rare finding in the adult human. In particular, continuous developments in imaging techniques have made radiologists become increasingly aware of this anatomical entity in recent years. The role of the PSS as a major encephalic drainage pathway and its potential implication in pathological conditions such as intracranial venous hypertension are discussed. [source] | ||||||||||