scholarly journals Genetics of Mutations Affecting the Development of a Barley Floral Bract

Genetics ◽  
2000 ◽  
Vol 154 (3) ◽  
pp. 1335-1346 ◽  
Author(s):  
Carlo Pozzi ◽  
Primetta Faccioli ◽  
Valeria Terzi ◽  
Antonio Michele Stanca ◽  
Sergio Cerioli ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sem Analysis ◽  
Floral Bract ◽  
Morphological Description ◽  
Wild Type ◽  
Linkage Groups ◽  
Recessive Mutations ◽  
D 23 ◽  
Vegetative Leaf ◽  
Scanning Electron

Abstract Two groups of mutants that affect the morphology of the lemma, a floral bract of barley, are described. The first comprises phenotypes associated with mutant alleles of calcaroides loci. On the lemma of these mutants, a well-organized neomorphic structure is formed, termed the sac. We provide a morphological description of wild-type (WT) and mutant lemmas, based on scanning electron microscopy (SEM), showing that both consist of similar tissues, but that the mutant is characterized by reversed growth polarity. The sac is a unique structure among grasses, and it is remarkable that recessive mutations at five different genetic loci lead to the same organ. The second group of mutants carry recessive alleles of two leafy lemma genes, both of which are necessary to cause the transformation of the lemma into a structure having all characteristics of a vegetative leaf, as shown by SEM analysis. The presence of sheath, blade, and ligule in the mutant lemma suggests that wild-type lemma development is interrupted at a leaf-like stage. The genes cal a, b, C, d, 23, lel1, and lel2 have now been mapped at precise positions on linkage groups 2, 7, 7, 3, 7, 5, and 7, respectively. The mutants considered in this article are unaffected in other floral organs. A model for lemma development is suggested.

scholarly journals External female genitalia of Triatoma jatai, Triatoma costalimai and Triatoma williami (Hemiptera: Reduviidae: Triatominae)

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Simone Caldas Teves ◽  
Teresa Cristina Monte Gonçalves ◽  
Simone Patrícia Carneiro de Freitas ◽  
Catarina Macedo Lopes ◽  
Ana Laura Carbajal-de-la-Fuente ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
External Genitalia ◽  
Sem Analysis ◽  
Morphological Description ◽  
Dichotomous Key ◽  
Laboratory Colony ◽  
Viii And Ix ◽  
Morphological Differences ◽  
Scanning Electron

Abstract Background Taxonomic identification of triatomines is generally performed based on aspects of their external morphology. However, the use of a multidisciplinary approach, considering morphological aspects of the external genitalia, morphometry, genetics, and phylogeography has been suggested, especially for similar and/or cryptic species. The rupestral species Triatoma jatai Gonçalves et al., 2013, Triatoma costalimai Verano & Galvão, 1959 and Triatoma williami Galvão et al., 1965, which are morphologically similar, have been found naturally infected with Trypanosoma cruzi (Chagas, 1909) in wild, peridomestic, and intradomestic environments, representing a risk of new outbreaks of Chagas disease. This study presents morphological description complementation of these species, with an emphasis on the structures of the female external genitalia, using scanning electron microscopy. Methods The females of T. jatai and T. costalimai (n = 10 of each) were captured in the Brazilian municipalities of Paranã and Aurora do Tocantins and were identified with the use of a dichotomous key for the Matogrossensis subcomplex. Females of T. williami (n = 5), were obtained from a laboratory colony. The females were cut transversely at the sixth abdominal segment and examined under scanning electron microscopy (SEM) at the Oswaldo Cruz/Fiocruz Institute Electronic Microscopy Platform. Results It was possible to differentiate the three species based on the characteristics of urotergites VII, VIII and IX and urosternite VII, as well as the genital plaques, gonocoxites, and gonapophyses. To our knowledge, morphological differences in the spines present on gonapophysis 8 in triatomines are described here for the first time. Conclusions The results show that external genitalia of females are useful structures to differentiate T. costalimai, T. jatai and T. williami. SEM analysis contributes to and corroborates, together with other tools morphological and molecular, the distinction of the three species.

SEM analysis of fish scale cross sections: A technique study

1992 ◽  
Vol 50 (1) ◽  
pp. 744-745
Author(s):  
M.E. Lee ◽  
A. Moller ◽  
P.S.O. Fouche ◽  
I.G Gaigher
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Sections ◽  
Soft Tissues ◽  
Close Association ◽  
Sem Analysis ◽  
Fish Scale ◽  
Fish Scales ◽  
Micro Structures ◽  
Scanning Electron

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.

Development of Alginate Based Active Films Containing Turmeric Essential Oil

2020 ◽  
Vol 861 ◽  
pp. 378-382
Author(s):  
Sophoan Phal ◽  
Muhammad Rafiullah Khan ◽  
Pattarin Leelaphiwat ◽  
Vanee Chonhenchob
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Water Vapor ◽  
Essential Oil ◽  
Sem Analysis ◽  
Film Properties ◽  
Elongation At Break ◽  
Control Film ◽  
Scanning Electron

Sodium alginate based films containing turmeric oil (TEO) at different concentrations (1, 2 and 3%) were developed. The film with no TEO was used as control. Incorporation of TEO had the effects on the film properties. With increasing TEO concentrations, thickness, elongation at break, permeability of oxygen and water vapor of the films significantly (p ≤ 0.05) increased. Whereas moisture content, tensile strength and modulus of elasticity significantly (p ≤ 0.05) decreased. Scanning electron microscopy (SEM) analysis showed more numerous pores and rougher surface of the antifungal films than the control film.

Redescription of Diplogasteroides nasuensis Takaki, 1941 and D. magnus Völk, 1950 (Nematoda: Diplogastrina) associated with Scarabaeidae (Coleoptera)

Nematology ◽  
2001 ◽  
Vol 3 (8) ◽  
pp. 817-832 ◽  
Author(s):  
Walter Sudhaus ◽  
Karin Kiontke ◽  
Albrecht Manegold
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Broad Sense ◽  
Morphological Description ◽  
Scanning Electron

AbstractA detailed morphological description is presented of Diplogasteroides nasuensis Takaki, 1941 and D. magnus Völk, 1950, using light and scanning electron microscopy. Neoaplectana melolonthae Weiser, 1958 and Diplogasteroides (Rhabdontolaimus) berwigi Rühm, 1959 are synonymised with D. nasuensis. This gonochoristic species is distinguished from the hermaphroditic D. magnus by the dorsal metastomal decoration which consists of bristle-like protrusions instead of a more or less uniform tooth. The spermatocytes in D. nasuensis are twice as big as those in hermaphrodites of D. magnus. Dauer juveniles of D. nasuensis are considerably bigger than those of D. magnus. Dauer juveniles of both species are present on wood cockchafer (Melolontha hippocastani) larvae and adults but, on adult beetles, D. nasuensis dauer juveniles enter the genital pouch, whereas those of D. magnus are found under the hind coxae. In Germany, D. nasuensis is found only on M. hippocastani. D. magnus dauer juveniles are also found on a variety of other Scarabaeidae. Further small differences distinguish the two species. The genus Diplogasteroides is proposed to be taken in a broad sense. Several genera names are synonymised with Diplogasteroides.

Deepwater sculpin, Myoxocephalus thompsoni (Girard) from a Pleistocene nodule, Green Creek, Ontario, Canada

1979 ◽  
Vol 16 (8) ◽  
pp. 1621-1628 ◽  
Author(s):  
Donald E. Champagne ◽  
C. R. Harington ◽  
Don E. McAllister
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Habitat Preferences ◽  
Sem Analysis ◽  
Lake Basin ◽  
Lacustrine Environment ◽  
Clay Matrix ◽  
Summer Temperatures ◽  
Scanning Electron ◽  
Ultraviolet Lamp

A nodule containing the cranium of a deepwater sculpin, Myoxocephalus thompsoni (Girard), was discovered in Pleistocene Champlain Sea deposits at Green Creek, 10 km east of Ottawa, Ontario, Canada, and represents the first fossil reported for the species. It provides an additional basis for refuting derivation of the species from a post-Wisconsin marine submergence and suggests an origin at the beginning of the Wisconsin or earlier. Habitat preferences of the species favour an oligotrophic lacustrine environment with bottom summer temperatures below 8 °C in the Champlain Sea or nearby lake basin. The head length of the fossil is 28 mm, the estimated standard length 86 mm. Use of a longwave ultraviolet lamp with the fossil improved contrast between the bones and the clay matrix in photographs. Scanning electron microscopy (SEM) analysis of bone in the fossil failed to detect the presence of strontium.

Morphology of Lignin-Polyurethane Blends

1989 ◽  
Vol 153 ◽  
Author(s):  
D. Feldman ◽  
M.A. Lacasse
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Sem Analysis ◽  
Accelerated Weathering ◽  
Dsc Analysis ◽  
Mechanical Mixing ◽  
Scanning Calorimetry ◽  
Two Phases ◽  
Scanning Electron

AbstractThe morphology of blended polyurethane (PU) sealants was studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The PU was modifided by mechanical mixing with various amounts of Lignin (L) to achieve a homogeneous blend. Specimens were subjected to control (C), accelerated weathering (AW), and natural weathering (NW) conditions. Results obtained from SEM analysis reveal an even distribution of L particles in the PU matrix. Furthermore, the SEM photomicrographs clearly emphasize the differing morphologies of the constituent phases. They also depict the differences in surface texture between control and aged specimens. The DSC analysis shows that the two phases are immiscible which is in agreement with observations by microscopy.

scholarly journals Use of different SEM techniques in the study of Tyrophagus putrescentiae (Acari: Acaridae) in Costa Rica

2013 ◽  
Vol 5 (2) ◽  
pp. 201-208
Author(s):  
Pamela Murillo ◽  
Hugo Aguilar ◽  
Ethel Sanchez
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Costa Rica ◽  
Morphological Characters ◽  
Morphological Description ◽  
Tyrophagus Putrescentiae ◽  
Viable Option ◽  
Efficient Procedure ◽  
Advantages And Disadvantages ◽  
Scanning Electron

Scanning electron microscopy (SEM) has been used as a tool to facilitate the morphological description of mites and to complement the information obtained from the light microscope. Unfortunately, several of SEM techniques used for soft-bodied mites such as Tyrophagus, have in many cases not shown the desired results. This investigation sought to develop an efficient procedure for preparing specimens of T. putrescentiae for SEM so that its major morphological characters could be observed and photographed. This species is the most important contaminant of tissue culture laboratories in Costa Rica. Seven methods were used to process the samples. The evaluated treatments showed differences in their ability to preserve the morphological structures of the specimens. The advantages and disadvantages of each treatment are discussed.  Mites processed using ethanol were the most viable option with method 3 being the procedure that showed the best results; this technique also reduced the time and costs of processing the specimens.KEY WORDSAcari, Acaridae, Tyrophagus putrescentiae, Scanning Electron Microscopy (SEM), SEM techniques

scholarly journals Detailed morphological description of Habronema clarki Foster & Chitwood, 1937, a nematode parasite of capybaras Hydrochoerus hydrochaeris (Linnaeus, 1766) in Brazil

2014 ◽  
Vol 23 (2) ◽  
pp. 251-254
Author(s):  
Estevam Guilherme Lux Hoppe ◽  
José Hairton Tebaldi ◽  
Daniel Fontana Ferreira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nematode Parasite ◽  
Morphological Data ◽  
Valid Species ◽  
Morphological Description ◽  
Hydrochoerus Hydrochaeris ◽  
Scanning Electron

The genus Habronema has four valid species, of which only two are properly known. The present study aimed to describe in detail the morphology of Habronema clarki through optical and scanning electron microscopy analyses. Our results showed that the labial morphology of this parasite is closer to H. muscae than to H. microstoma. Even so, the characteristic pseudolabia and the slightly convex border of the dorsal and ventral lips are sufficient to distinguish these nematodes. Additional morphological data are presented, thus contributing to the knowledge on this little known nematode. In addition, this study provides new locality records for this species.

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