scholarly journals A Preliminary Report on the Use of Bench-Top X-Ray Micro-Computerised Tomography to Study the Malpighian Tubules of the Overwintering Seven Spotted LadybirdCoccinella septempunctataL. (Coleoptera: Coccinellidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Duncan Bell ◽  
Lewis Woolnough ◽  
David Mortimore ◽  
Nick Corps ◽  
Diana M. Hudson ◽  
...  
Keyword(s):  
Coccinella Septempunctata ◽  
Ct Scanning ◽  
Small Sample ◽  
Malpighian Tubules ◽  
Micro Ct ◽  
Computerised Tomography ◽  
X Ray ◽  
High Concentrations ◽  
Very High ◽  
Metallic Pollutants

The application of micro-CT scanning techniques on a small sample of “Seven-spot ladybirds”Coccinella septempunctata,collected in December 2009, identified an accumulation of material with a very high, relative X-ray attenuation value in the malpighian tubules of most but not all of the individuals sampled. The passage of metals such as cadmium in soil through a food chain to finally accumulate in high concentrations in ladybirds and lacewings has been previously reported. The identification of the dense material found in our sample of ladybirds, its origin, and the process by which it accumulates in, and is processed by, the malpighian tubules is the challenge ahead. The authors speculate that a straightforward means of monitoring levels of metallic pollutants in the environment might emerge.

The initial stages in the action of an insecticidal delta-endotoxin of Bacillus thuringiensis var. israelensis on the epithelial cells of the malpighian tubules of the insect, Rhodnius prolixus

1988 ◽  
Vol 90 (1) ◽  
pp. 131-144
Author(s):  
S.H. Maddrell ◽  
N.J. Lane ◽  
J.B. Harrison ◽  
J.A. Overton ◽  
R.B. Moreton
Keyword(s):  
Bacillus Thuringiensis ◽  
Intercellular Junctions ◽  
Fluid Secretion ◽  
Malpighian Tubules ◽  
Ultrastructural Changes ◽  
Cytoplasmic Vacuolization ◽  
Large Numbers ◽  
Delta Endotoxin ◽  
High Concentrations ◽  
Very High

The effects of the 27 X 10(3) Mr insecticidal delta-endotoxin from Bacillus thuringiensis var. israelensis have been studied using, as a model system, isolated insect Malpighian tubules. At all concentrations of the toxin higher than 1 microgram ml-1 (4 X 10(−8) moll-1) applied to the outer surface of the tubules, fluid secretion failed within about 30 min. Except at very high concentrations, where failure always takes at least 30 s, there was an inverse relationship between the concentration of toxin and the time of failure of toxin-treated tubules. During exposure to toxin, the tubules were initially unaffected for a relatively long period and then rapid failure occurred. If the tubules were removed into toxin-free saline just before failure would have occurred, fluid secretion remained normal for at least 2 h, but on return to the origin toxin-containing saline failure was almost immediate. The toxin was found not to bind to the basement membrane. Ultrastructural changes became evident as tubule failure occurred. These initially involved modifications to the basal side of the cells, but later also to the luminal microvilli. Intercellular junctions became disassociated and cytoplasmic vacuolization occurred. The population of intramembranous particles in the basal membranes became reduced with time. Our findings suggest the following hypothesis for the initial stages in the interaction of the toxin with the tubules. Toxin molecules attach to the accessible cell membranes progressively and irreversibly. They do not readily associate by diffusing laterally in the membrane, so that toxic effects develop only when sufficiently large numbers of them attach close together. The molecules may then associate in some way as a complex, perhaps forming a pore in the membrane. Relatively few such pores lead rapidly to cell failure and death.

scholarly journals Finding fossils in Malapa breccia – medical CT scanning or micro-CT scanning?

2017 ◽  
Vol 113 (11/12) ◽  
Author(s):  
Jacqueline S. Smilg
Keyword(s):  
Computed Tomography ◽  
Lower Energy ◽  
Ct Scanning ◽  
Cost Effective ◽  
High Energy ◽  
X Rays ◽  
Micro Ct ◽  
X Ray ◽  
Mechanical Preparation ◽  
X Ray Computed

Computed tomography (CT) imaging of fossils has revolutionised the field of palaeontology, allowing researchers to gain a better understanding of fossil anatomy, preservation and conservation. Micro focus X-ray computed tomography (μXCT) has been far more extensively used for these purposes than medical CT (XCT) – mostly because of the exquisite detail that the μXCT scanning modality, using slices of micron thicknesses, can produce. High energy X-rays can potentially penetrate breccia more effectively than lower energy beams. This study demonstrates that lower energy beams produce superior images for prioritising breccia for preparation. Additionally, XCT scanners are numerous, accessible, fast and relatively cost-effective when compared to μXCT scanners – the latter are not freely available, scanning times are much longer and there are significant limitations on the size and weight of scannable objects. Breccia blocks from Malapa were scanned at high and lower energy and images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of μXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. The ability to choose fossil-bearing breccia, ahead of manual mechanical preparation by laboratory technicians, would allow for the optimal use of limited resources, manual preparatory skills as well as the curtailment of costs.

scholarly journals X-ray micro-CT scanning reveals temporal separation of male harm and female kicking during traumatic mating in seed beetles

2017 ◽  
Vol 284 (1856) ◽  
pp. 20170550 ◽  
Author(s):  
Liam R. Dougherty ◽  
Leigh W. Simmons
Keyword(s):  
Callosobruchus Maculatus ◽  
Ct Scanning ◽  
Three Dimensions ◽  
Micro Ct ◽  
Temporal Separation ◽  
X Ray ◽  
Seed Beetle ◽  
Proximate Mechanisms ◽  
Fitness Consequences ◽  
Seed Beetles

In the seed beetle Callosobruchus maculatus , the male intromittent organ is covered in sharp spines that pierce the female copulatory tract wall during mating. Although the fitness consequences of traumatic mating are well studied in this species, we know much less about how the male and female genitalia interact during mating. This is partly due to the fact that genital interactions occur primarily inside the female, and so are difficult to observe. In this study, we use X-ray micro-CT scanning to examine the proximate mechanisms of traumatic mating in C. maculatus in unprecedented detail. We show that this technique can be used to identify female tissue damage before the melanization of wound sites. We visualize the positioning of the male intromittent organ inside the female copulatory tract during mating, and show how this relates to tract wounding in three dimensions. By scanning pairs flash-frozen at different times during mating, we show that significant tract wounding occurs before the onset of female kicking. There is thus some degree of temporal separation between the onset of wounding and the onset of kicking, which supports recent suggestions that kicking is not an effective female counter-adaptation to reduce copulatory wounding in this species. We also present evidence that the sharp teeth protruding from the female tract wall are able to pierce the spermatophore as it is deposited, and may thus function to aid sperm release.

A Malpighian Tubule Lime Gland in an Insect Inhabiting Alkaline Salt Lakes

1989 ◽  
Vol 145 (1) ◽  
pp. 63-78 ◽  
Author(s):  
DAVID B. HERBST ◽  
TIMOTHY J. BRADLEY
Keyword(s):  
Malpighian Tubule ◽  
Cell Types ◽  
Chemical Precipitation ◽  
Malpighian Tubules ◽  
Salt Lakes ◽  
Alkaline Salt ◽  
X Ray ◽  
Posterior Pair ◽  
High Concentrations ◽  
Scanning Electron

The alkali fly, Ephydra hians Say, inhabits alkaline salt lakes which can contain concentrations of dissolved carbonate and bicarbonate as high as 500 mmol l−1. Larvae of the alkali fly possess two pairs of Malpighian tubules. The posterior pair has a morphology similar to that of the tubules of most other insects, but the anterior pair is modified into an enlarged gland containing white microsphere concretions. We describe the ultrastructure of all cell types in both pairs of tubules. Using scanning electron microscope (SEM) X-ray microanalysis and chemical CO2 quantification, we demonstrate that the concretions in the lime glands are composed of nearly pure calcium carbonate. Isolated preparations of lime gland tubules accumulate 45Ca significantly more rapidly than do normal tubules. Although similar to the rime concretions found in the Malpighian tubules of other Diptera, the lime glands of this insect may function to regulate the high concentrations of carbonate and bicarbonate encountered in their aquatic environment. It is proposed that the mechanism of this regulation may be chemical precipitation of carbonate/bicarbonate with calcium in the lumen of these specialized lime gland tubules.

scholarly journals Morpho-densitometric traits for quinoa (Chenopodium quinoa Willd.) seed phenotyping by two X-ray micro-CT scanning approaches

2019 ◽  
Vol 90 ◽  
pp. 102829 ◽  
Author(s):  
Laura Gargiulo ◽  
Åsa Grimberg ◽  
Ritva Repo-Carrasco-Valencia ◽  
Anders S. Carlsson ◽  
Giacomo Mele
Keyword(s):  
Chenopodium Quinoa ◽  
Ct Scanning ◽  
Micro Ct ◽  
X Ray

scholarly journals Snow replica method for three-dimensional X-ray microtomographic imaging

2009 ◽  
Vol 55 (192) ◽  
pp. 631-639 ◽  
Author(s):  
Martin Heggli ◽  
Esther Frei ◽  
Martin Schneebeli
Keyword(s):  
High Vacuum ◽  
Three Dimensional ◽  
Electromagnetic Properties ◽  
Micro Ct ◽  
X Ray ◽  
Automatic Image Processing ◽  
Very High Spatial Resolution ◽  
Manual Interaction ◽  
Very High ◽  
Snow Samples

AbstractVisualization and quantification of snow structures at a scale of a few millimetres is important in understanding the mechanical, thermal and electromagnetic properties of snow. Surface sections and, to an even greater degree, three-dimensional (3-D) reconstructions of cast snow samples are difficult to prepare, and automatic image processing is notoriously difficult and often requires manual evaluation. Here, we present a new method to measure the 3-D structure of cast snow samples. Snow samples cast with diethyl phthalate (DEP) and frozen are cut to a sample size a few centimetres in diameter and up to 10 cm in height. The ice of these samples is then sublimated in high vacuum and the remaining negative structure (replica) is imaged using X-ray microtomography (micro-CT). The accuracy of the method is demonstrated by comparing micro-CT scans of the original snow structure and the replica. The method described here allows easy transportation of samples, requires little manual interaction, has a very high spatial resolution of up to 10 μm and is environmentally friendly.

scholarly journals Tracking the Magmatic Flow in a Dyke-Sill Hybrid System using a Multi-Method Approach (AMS, SPO, X-ray micro-CT) for Petrofabrics Characterization (Lessines, Belgium)

2020 ◽  
Author(s):  
Antoine Triantafyllou ◽  
Jean-Marc Baele ◽  
Hervé Diot ◽  
Veerle Cnudde ◽  
Redouane Meftah ◽  
...  
Keyword(s):  
Hybrid System ◽  
Ct Scanning ◽  
Hydrothermal Activity ◽  
Micro Ct ◽  
Upper Ordovician ◽  
Heterogeneous Distribution ◽  
X Ray ◽  
The North ◽  
Magmatic Body ◽  
Multi Method Approach

<p>Understanding how magmas are transported and collected within the crust is crucial for constraining the dynamic of shallow plumbing volcanic systems and associated hydrothermal activity. This study focuses on the Lessines dioritic intrusion exposed in the SW margin of the Brabant Massif in Belgium. The kilometric subvolcanic body was emplaced around 419 Ma and is thought to result from the emplacement of multiple sills which intruded a lithostratigraphic discontinuity within Upper Ordovician sedimentary units. Our study aims to constrain how magmatic flow is recorded through different fabrics, how this flow varies across the solidified magmatic intrusion and how primary fabrics can be affected by subsequent hydrothermal overprint.</p><p>The petrofabric of 40 oriented diorite samples was investigated with a multi-methods approach: (i) Anisotropy of Magnetic Susceptibility (AMS) along with K-temperature curves determined using low field KLY-4S Kappabridge susceptibilimeter (at LIENS lab, University of La Rochelle, France), (ii) Shape Preferred Orientations (SPO) of melanocratic phenocrysts (pseudomorphosed amphibole and biotite) as well as leucocratic phenocrysts (quartz and sericitized felspars s.l.) determined by the Intercepts method applied on optical scans of three adjacent cut faces of each sample, (iii) X-ray micro-CT scanning of five selected samples using the HECTOR device at UGCT lab (Ghent University, Belgium).</p><p>AMS and melanocratic fabrics SPO are mainly marked by prolate shaped ellipsoids. Both subsets show similar and homogeneous orientation of their structures through the studied area, with E-W striking foliations dipping 70° to the North to subvertical. Leucocratic petrofabric SPO shows more heterogeneous distribution with a similar E-W to N120-striking foliations but generally subhorizontal to low dipping structures (< 30°). This discrepancy is thought to be due to differential record of the subvolcanic phenocrysts during the ultimate emplacement and solidification of the Lessines magmatic body. These results combined to field observations (e.g., enclave orientations, columnar joints, borehole logs) suggest that the Lessines intrusion is a complex dyke-sill hybrid system, made of a main subvertical dyke-like structure that fed lateral sills bodies.</p>

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