Structural analysis of embryogenesis of Leiarius marmoratus (Siluriformes: Pimelodidae)

Zygote ◽  
2014 ◽  
Vol 23 (5) ◽  
pp. 742-757
Author(s):  
Isângela Rodrigues Oliveira-Almeida ◽  
Hellen Buzollo ◽  
Raphael da Silva Costa ◽  
Rosicleire Veríssimo-Silveira ◽  
Fábio Porto-Foresti ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Analysis ◽  
Embryonic Development ◽  
Incubation Period ◽  
Reproductive Biology ◽  
Fish Species ◽  
Biological Data ◽  
Stages Of Development ◽  
Additional Information ◽  
Time Zero

SummaryEmbryological studies in fish species are useful to the understanding of their biology and systematics. The available biological data in Leiarius marmoratus are scarce and additional information about its reproductive biology is needed, mainly because this species has been commercially exploited and used in production of hybrid lineages. In order to evaluate the temporal–morphological embryonic modifications in L. marmoratus, samples of nearly 200 embryos were collected at random at different stages of development, starting from fecundation (time zero). Embryos were fixed in modified Karnovsk's solution and 2.5% glutaraldehyde, processed and analysed under optic and electron microscopy. The incubation period of L. marmoratus was equal to 14.42 h at a mean temperature of 28.3 ± 0.07°C. The following stages of embryonic development were established: zygote, cleavage, gastrula, organogenesis and hatching. These stages were divided into phases, as follows: cleavage – phases of 2, 4, 8, 16, 32 and 64 cells and morula; gastrula – phases of 25, 50, 75 and 90% of epiboly and blastopore closure; and organogenesis – neurula, segmentation and pre-larval phases. The embryogenesis of L. marmoratus was typical of neotropical teleosteans, with peculiarities in species development.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

scholarly journals Structural analysis of the human SYCE2–TEX12 complex provides molecular insights into synaptonemal complex assembly

Open Biology ◽  
2012 ◽  
Vol 2 (7) ◽  
pp. 120099 ◽  
Author(s):  
Owen R. Davies ◽  
Joseph D. Maman ◽  
Luca Pellegrini
Keyword(s):  
Structural Analysis ◽  
Synaptonemal Complex ◽  
Recurrent Miscarriage ◽  
Central Element ◽  
Biological Data ◽  
Structural Basis ◽  
Structural Framework ◽  
Chromosome Synapsis ◽  
Heterotypic Interactions ◽  
Physical Features

The successful completion of meiosis is essential for all sexually reproducing organisms. The synaptonemal complex (SC) is a large proteinaceous structure that holds together homologous chromosomes during meiosis, providing the structural framework for meiotic recombination and crossover formation. Errors in SC formation are associated with infertility, recurrent miscarriage and aneuploidy. The current lack of molecular information about the dynamic process of SC assembly severely restricts our understanding of its function in meiosis. Here, we provide the first biochemical and structural analysis of an SC protein component and propose a structural basis for its function in SC assembly. We show that human SC proteins SYCE2 and TEX12 form a highly stable, constitutive complex, and define the regions responsible for their homotypic and heterotypic interactions. Biophysical analysis reveals that the SYCE2–TEX12 complex is an equimolar hetero-octamer, formed from the association of an SYCE2 tetramer and two TEX12 dimers. Electron microscopy shows that biochemically reconstituted SYCE2–TEX12 complexes assemble spontaneously into filamentous structures that resemble the known physical features of the SC central element (CE). Our findings can be combined with existing biological data in a model of chromosome synapsis driven by growth of SYCE2–TEX12 higher-order structures within the CE of the SC.

Mitosis in Drosophila

1989 ◽  
Vol 92 (2) ◽  
pp. 137-146 ◽  
Author(s):  
D.M. Glover
Keyword(s):  
Genetic Analysis ◽  
Embryonic Development ◽  
Protein Interactions ◽  
Dynamic Process ◽  
Early Embryogenesis ◽  
Female Sterility ◽  
Protein Protein Interactions ◽  
Stages Of Development ◽  
Cell Cycles

Drosophila is an attractive organism in which to study both the rapid rounds of mitosis typical of embryonic development in many species, and the longer cell cycles of diploid tissues later in development. Mutations in genes essential for mitosis in Drosophila may result in lethality in late embryonic, larval or pupal stages of development. In addition, mutations in many genes required for the nuclear divisions of early embryogenesis have been found in screens for female sterility. The mitotic mutations have phenotypes indicative of lesions at a variety of mitotic stages. A combined molecular and genetic analysis of these genes has the potential to unravel the complex set of protein-protein interactions that occur in this dynamic process.

scholarly journals Light and electron microscopy study of late embryonic development in the land snail Limicolaria flammea (Müller) (Pulmonata, Achatinidae)

2007 ◽  
Vol 24 (2) ◽  
pp. 436-441 ◽  
Author(s):  
Rosemary I. Egonmwan
Keyword(s):  
Electron Microscopy ◽  
Embryonic Development ◽  
Light And Electron Microscopy ◽  
Microscopy Study ◽  
Land Snail ◽  
Electron Microscopy Study ◽  
Advanced Embryo ◽  
Embryonic Shell ◽  
Advanced Stages ◽  
Late Stages

The late stages of embryogenesis in the achatinid land snail Limicolariaflammea (Müller, 1774) were described using light and electron microscopy. Embryos at various stages of development were present in the eggs during the first hour after they were laid, from 4-cell blastulae to morulae and fairly advanced stages. The advanced embryo which was fully developed on the second day bears a long cephalic sac, first to be developed, attached to the embryo and a podocyst which is attached to the foot of the embryo. Both of these structures are reduced in size as embryogenesis progresses until they finally disappear at about the 7th day after the egg was deposited. The embryonic shell was apparent on the second day and spiral coiling was apparent at about day 5. The spiral shell had one whorl when formed and more spirals were added so that at hatching the young snails had three whorls.

scholarly journals SOME TRENDS IN FRESHWATER TROPICAL AQUACULTURE AND THEIR IMPACT ON STUDIES OF THE CLIMBING PERCH ANABAS TESTUDINEUS (ANABANTIDAE) REPRODUCTIVE BIOLOGY

Fisheries ◽  
2020 ◽  
Vol 2020 (4) ◽  
pp. 85-89
Author(s):  
Dmitry Zworykin
Keyword(s):  
Reproductive Biology ◽  
Fish Species ◽  
Applied Research ◽  
Tropical Fish ◽  
Native Fish ◽  
Turn Of The Millennium ◽  
Anabas Testudineus ◽  
Climbing Perch ◽  
Contemporary Science ◽  
Tropical Aquaculture

The dynamics of publication activities devoted to the climbing perch from 1969 to 2018 is analyzed. It is shown that sharp increases in the number of publications at the turn of the millennium coincide with changes in international and national strategies for tropical fish aquaculture, focusing on cultivation of fast-growing native fish species and small farms support. These programs have led to a surge in applied research and publications on the climbing perch, as one of the most promising species. Unfortunately, some of these papers have been published in journals that are unreliable according to the criteria of contemporary science and contain controversial conclusions. Certain consequences of these trends are noted and challenges outlined.

scholarly journals Reproductive Biology of Ovigerous Female Emerita emeritus (Crustacea, Decapoda) in Bengkulu Coastal Waters, Indonesia: Egg Production and Reproductive Output

2016 ◽  
Vol 74 (3) ◽  
pp. 103-109 ◽  
Author(s):  
Ouratul Edritanti ◽  
Achmad Farajallah ◽  
Yusli Wardiatno
Keyword(s):  
Embryonic Development ◽  
Surface Temperature ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Egg Production ◽  
Reproductive Output ◽  
Ovigerous Female ◽  
Abundant Species ◽  
Sea Surface ◽  
Egg Volume

Abstract Emerita emeritus is an abundant species in Bengkulu coastal waters, but the knowledge of its reproductive biology is poor. The present study was conducted to elucidate the reproductive aspects of ovigerous female E. emeritus, including fecundity, egg volume and reproductive output. This study was conducted between January 2015 and January 2016 in Bengkulu coastal waters, Indonesia. Samples were collected manually using shovels and hands. The results showed that ovigerous females occurred every month. Fecundity increased significantly in ovigerous females proportional to the size. No correlation was shown between sea surface temperature and egg production. Fecundity and reproductive output decreased throughout the embryonic development.

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