The use of inherited abnormalities in studies on the embryogenesis of Dermestes maculatus (Coleoptera)

Development ◽  
1964 ◽  
Vol 12 (3) ◽  
pp. 539-549
Author(s):  
D. A. Ede ◽  
Anne M. Rogers
Keyword(s):  
Large Range ◽  
Normal Embryo ◽  
Primary Defect ◽  
Insect Embryogenesis ◽  
Dermestes Maculatus ◽  
Tissue Interactions ◽  
Developmental Mechanisms ◽  
Embryological Analysis

The possibility of using inherited abnormalities in place of conventional experimental embryological methods has been explored by several workers in Drosophila, where there is a large range of lethal and female sterile genes readily available (reviewed Waddington, 1956). These genes are usually pleiotropic, i.e. with manifold effects, and tracing these diverse effects back as far as possible to a single primary defect gives information about the corresponding developmental mechanisms in the normal embryo. Two disadvantages have attended these studies: (1) dipteran embryology is extremely specialized and difficult to relate to that of other insects, (2) it is almost entirely mosaic in character, and therefore throws no light on the important subject of tissue interactions. The present study was undertaken in order to extend this method of embryological analysis to an insect with a less specialized embryology, and hence to show its applicability to studies on insect embryogenesis in general.

Evolutionary developmental biology of the tetrapod limb

Development ◽  
1994 ◽  
Vol 1994 (Supplement) ◽  
pp. 163-168
Author(s):  
J. Richard Hinchliffe
Keyword(s):  
Gene Expression ◽  
Developmental Biology ◽  
Early Development ◽  
Homeobox Gene ◽  
Evolutionary Developmental Biology ◽  
Epigenetic Factors ◽  
Limb Buds ◽  
Developmental Mechanisms ◽  
Direct Gene ◽  
Embryological Analysis

New insights into the origin of the tetrapod limb, and its early development and patterning, are emerging from a variety of fields. A wide diversity of approaches was reported at the BSDB Spring Symposium on `The Evolution of Developmental Mechanisms' (Edinburgh, 1994); here I review the contributions these various approaches have made to understanding the evolutionary developmental biology of the tetrapod limb. The fields covered included palaeontology, descriptive embryology, experimental embryological analysis of interactions within developing limbs plus description and manipulation of homeobox gene expression in early limb buds. Concepts are equally varied, sometimes conflicting, sometimes overlapping. Some concern the limb `archetype' (can the palaeontologists and morphologists still define this with precision? how far is there a limb developmental bauplan?); others are based on identification of epigenetic factors (eg secondary inductions), as generating pattern; while yet others assume a direct gene-morphology relationship. But all the contributors ask the same compelling question: can we explain both the similarity (homology) and variety of tetrapod limbs (and the fins of the Crossopterygians) in terms of developmental mechanisms?

Developmental processes underlying heterochrony as an evolutionary mechanism

1984 ◽  
Vol 62 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Brian K. Hall
Keyword(s):  
Growth Rate ◽  
Morphological Change ◽  
Mitotic Activity ◽  
Skeletal Development ◽  
Relative Time ◽  
Evolutionary Mechanism ◽  
Rate Of Development ◽  
Tissue Interactions ◽  
Lower Jaw ◽  
Developmental Mechanisms

Heterochrony, the change in the relative time of appearance or rate of development of a character during phylogeny, has been an important mechanism for generating morphological change during evolution. Retardation and acceleration are two processes which drive heterochrony. I have considered the developmental mechanisms which govern three parameters of heterochrony (when growth starts, growth rate, when growth stops) during skeletal development and conclude that the number and mitotic activity of the cells in the initial skeletal condensation emerges as a fundamental level of control. A developmental explanation for heterochrony should therefore focus on what controls the size of condensation and where and when they arise. Inductive tissue interactions regulate the formation of the condensations in which skeletal elements form, and the timing of these interactions can be modified genetically. As an example, evidence is presented to show that the timing of the interaction which leads to the formation of Meckel's cartilage in the lower jaw varies from one vertebrate group to another, being earlier in birds and later in mammals than it is in amphibians. Variation in the timing of inductive tissue interactions is identified as one mechanism controlling skeletal condensations, and therefore as one possible basis for heterochrony.

An ultrastructural study of vegetative incompatibility in plants

1978 ◽  
Vol 36 (2) ◽  
pp. 436-437
Author(s):  
Randy Moore
Keyword(s):  
Ultrastructural Study ◽  
Cell Walls ◽  
Growth And Development ◽  
Solanum Pennellii ◽  
Initial Product ◽  
Basic Aspect ◽  
Tissue Interactions ◽  
Graft Interface ◽  
Antigen Antibody ◽  
Standard Fixation

Cell and tissue interactions are a basic aspect of eukaryotic growth and development. While cell-to-cell interactions involving recognition and incompatibility have been studied extensively in animals, there is no known antigen-antibody reaction in plants and the recognition mechanisms operating in plant grafts have been virtually neglected.An ultrastructural study of the Sedum telephoides/Solanum pennellii graft was undertaken to define possible mechanisms of plant graft incompatibility. Grafts were surgically dissected from greenhouse grown plants at various times over 1-4 weeks and prepared for EM employing variations in the standard fixation and embedding procedure. Stock and scion adhere within 6 days after grafting. Following progressive cell senescence in both Sedum and Solanum, the graft interface appears as a band of 8-11 crushed cells after 2 weeks (Fig. 1, I). Trapped between the buckled cell walls are densely staining cytoplasmic remnants and residual starch grains, an initial product of wound reactions in plants.

Small Computer System for Micrograph Analysis

1981 ◽  
Vol 39 ◽  
pp. 270-271
Author(s):  
J. F. Hainfeld ◽  
J. S. Wall
Keyword(s):  
Large Range ◽  
Small Computer ◽  
Black And White ◽  
Contour Maps ◽  
Points Of Interest ◽  
Computer Aided Analysis ◽  
Specialized Hardware ◽  
Additional Memory ◽  
Selection Of ◽  
Publication Quality

Cost reduction and availability of specialized hardware for image processing have made it reasonable to purchase a stand-alone interactive work station for computer aided analysis of micrographs. Some features of such a system are: 1) Ease of selection of points of interest on the micrograph. A cursor can be quickly positioned and coordinates entered with a switch. 2) The image can be nondestructively zoomed to a higher magnification for closer examination and roaming (panning) can be done around the picture. 3) Contrast and brightness of the picture can be varied over a very large range by changing the display look-up tables. 4) Marking items of interest can be done by drawing circles, vectors or alphanumerics on an additional memory plane so that the picture data remains intact. 5) Color pictures can easily be produced. Since the human eye can detect many more colors than gray levels, often a color encoded micrograph reveals many features not readily apparent with a black and white display. Colors can be used to construct contour maps of objects of interest. 6) Publication quality prints can easily be produced by taking pictures with a standard camera of the T.V. monitor screen.

Spherulite Structures in a Melt Spun Fe-Ni Austenitic Steel

1985 ◽  
Vol 43 ◽  
pp. 52-53
Author(s):  
G. M. Michal ◽  
T. K. Glasgow ◽  
T. J. Moore
Keyword(s):  
Austenitic Steel ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Large Range ◽  
Amorphous Structure ◽  
Nucleation And Growth ◽  
Ni Alloys ◽  
Melt Spun ◽  
Crystal Fibers ◽  
Rapidly Solidified

Large additions of B to Fe-Ni alloys can lead to the formation of an amorphous structure, if the alloy is rapidly cooled from the liquid state to room temperature. Isothermal aging of such structures at elevated temperatures causes crystallization to occur. Commonly such crystallization pro ceeds by the nucleation and growth of spherulites which are spherical crystalline bodies of radiating crystal fibers. Spherulite features were found in the present study in a rapidly solidified alloy that was fully crysstalline as-cast. This alloy was part of a program to develop an austenitic steel for elevated temperature applications by strengthening it with TiB2. The alloy contained a relatively large percentage of B, not to induce an amorphous structure, but only as a consequence of trying to obtain a large volume fracture of TiB2 in the completely processed alloy. The observation of spherulitic features in this alloy is described herein. Utilization of the large range of useful magnifications obtainable in a modern TEM, when a suitably thinned foil is available, was a key element in this analysis.

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

PHYTOCHEMICAL SCREENING AND LARVICIDAL EFFECT EVALUATION OF AZADIRACHTA INDICA (L) LEAF EXTRACT ON DERMESTES MACULATUS (DE GEER, 1774) INFESTATION OF SMOKED CLARIAS GARIEPINUS (BURCHELL, 1822)

2020 ◽  
Vol 4 (2) ◽  
pp. 41-45
Author(s):  
Sadam Sulaiman Indabo ◽  
Rufai Zakari
Keyword(s):  
Azadirachta Indica ◽  
Leaf Extract ◽  
Standard Procedure ◽  
Clarias Gariepinus ◽  
Phytochemical Screening ◽  
Range Finding ◽  
Dermestes Maculatus ◽  
Randomized Design ◽  
Fish Samples ◽  
Initial Source

Dermestes maculatus is a major pest of stored fish in Nigeria, fish is preserved with highly persistent synthetic chemicals. There have been an increasing effort at developing plant-based toxicants that are environmentally friendly. Therefore, this study was conducted to screen the leaf extract of Azadirachta indica for phytochemical constituents. The efficacy of the methanolic leaf extract of the plant against D. maculatus was also evaluated. The leaves of A. indica were obtained, processed and taken to laboratory for methanolic extraction. Phytochemical screening was carried out to identify saponins, flavonoids, alkaloids, tannins, steroids, cardiac glycosides, glycosides, triterpenes and carbohydrates using standard procedure.  Both clean and infested samples of smoke-dried Clarias gariepinus were purchased from Sabon Gari Market, Zaria. The infested samples were used as initial source of D. maculatus larvae. Range finding test was carried out prior to the bioassay. During the bioassay, clean un-infested fish samples were weighed and introduced into kilner jars and respective dosages of 0.2g, 0.4g, 0.6g and 0.8g of extract were added. Another set of fish samples without the extract were maintained as control. The experiment was arranged in Completely Randomized Design with three replicates. Fifteen larvae of D. maculatus were introduced into both treated and control containers and covered. Mortality was recorded after 24, 48, 72 and 96 hours. Data obtained revealed an increase in mortality with increasing dose and time. Mortality ranged from 1.67 to 11.00. Therefore, leaf extract of A. indica should be incorporated in the development of larvicide against D. maculatus.   

Relationship Analysis of Islamic Banking between Malaysia and Pakistan

2018 ◽  
Vol 5 (4) ◽  
pp. 1-6
Author(s):  
Khurram Faisal Jamal
Keyword(s):  
Large Range ◽  
Primary Objective ◽  
Islamic Banking ◽  
Islamic Banks ◽  
Relationship Analysis ◽  
Banking Institutions ◽  
Qualitative Technique ◽  
Performance Problem ◽  
Very High ◽  
Product Preference

Islamic banking is basically a system of financial intermediation, its primary objective is to avoid receipt and payment of interest. Islam does not only prohibit dealing with interest but also with liquor, pork, gambling, pornography and any other thing which are considered haram according to Shariah. The objectives of the research is to study and describe the Islamic financing techniques used by Islamic banking institutions in Malaysia and Pakistan. For this research seven variables Promotion, Product, Preference, Knowledge, Performance, Problem and Infrastructure was taken. Qualitative technique was used to answer the research objective. The findings of research indicate that lack of awareness of Islamic banking is very high in Pakistan as compared to Malaysia. A few promotions were used by Islamic banks in Pakistan while in Malaysia customers are knowledgeable about Islamic banking because banks promote them aggressively. There is a need of government and education sector support to promote Islamic banking in both countries. The study also found that Islamic banks in Malaysia have large range of products as compared to Pakistan. The practitioners from both countries are agreed at this point that BBA, Ijarah and Murabaha are more profitable and less risky than Musharaka and Mudaraba. The Islamic banking products are almost used for same purposes in both countries while some differences are also exists.  Keywords: Islamic Finance, Comparative Study, Malaysia, Pakistan

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