The Thoracic Glands of Hemiptera Heteroptera

1954 ◽  
Vol s3-95 (30) ◽  
pp. 231-244
Author(s):  
M. J. WELLS
Keyword(s):  
Salivary Gland ◽  
Embryonic Development ◽  
Nerve Supply ◽  
Accessory Glands ◽  
Dysdercus Cingulatus ◽  
Almost All ◽  
Gland System

The thoracic glands of the pyrrhocorid Dysdercus cingulatus are described. They originate in the second maxillary segment and grow backwards with the salivary gland system. During post-embryonic development the gland nuclei increase in size but not in numbers. In each instar they enlarge, discharge their secretion, and shrink. The thoracic glands of ten other Heteroptera from eight families are described. All consist of large granular nuclei with little surrounding cytoplasm, most commonly arranged as a pair of elongated ductless glands lying parallel to the salivary ducts and attached distally to either the principal or the accessory glands. The thoracic glands are well supplied with tracheoles, but unlike other insects in which corresponding organs have been described, do not appear to have a nerve supply. The number of nuclei in each gland is surprisingly constant, being about 300 in almost all the species examined, the volume of the gland being greater in the larger insects by increase in the size of individual nuclei. The glands disappear very rapidly after the last moult.

Early changes in limb buds of chick embryos after thalidomide treatment

Development ◽  
1966 ◽  
Vol 16 (2) ◽  
pp. 289-300
Author(s):  
A. Jurand
Keyword(s):  
Embryonic Development ◽  
Experimental Investigations ◽  
Experimental Production ◽  
Chick Embryos ◽  
Teratogenic Effects ◽  
Limb Buds ◽  
Experimental Animals ◽  
Almost All ◽  
Thalidomide Treatment

Since the first observations of hypoplastic and aplastic thalidomide deformities in infants (McBride, 1961; Lenz, 1962), the literature on this subject has grown to many hundreds of communications. Experimental investigations in almost all cases have been undertaken to show whether thalidomide and its metabolites have any teratogenic effects in experimental animals. Numerous review papers are available on this subject, e.g. Giroud, Tuchmann-Duplessis & Mercier-Parot (1962), Somers (1963), and Salzgeber & Wolff (1964). Chick embryos did not seem for some time to be suitable for experimental production of typical thalidomide deformities. However, Kemper (1962a, b), Yang, Yang & Liang (1962). Boylen, Home & Johnson (1963) and Leone (1963) have shown that thalidomide can produce a whole range of ectromelian deformities provided that it is introduced into the egg at a particular period of embryonic development.

scholarly journals Exocrine glands of Schwarziana quadripunctata (Hymenoptera, Apinae, Meliponini)

2001 ◽  
Vol 61 (3) ◽  
pp. 497-505 ◽  
Author(s):  
C. CRUZ-LANDIM ◽  
R. D. REGINATO
Keyword(s):  
Salivary Gland ◽  
Dufour Gland ◽  
Exocrine Glands ◽  
Degree Of Maturity ◽  
Gland System

This article describes the location, anatomy, histology and ontogeny of adult Schwarziana quadripunctata exocrine glands. These glands appear either as individualized organs (salivary gland system and Dufour gland) or as epidermis differentiation (tegumentary glands). Variations in the occurrence and degree of development among colony components with regard to their degree of maturity are also described.

The Conversion of Yolk into Cytoplasm in the Chick Blastoderm as shown by Electron Microscopy

Development ◽  
1958 ◽  
Vol 6 (1) ◽  
pp. 149-161
Author(s):  
Ruth Bellairs
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Embryonic Development ◽  
Light Microscopy ◽  
Morphological Changes ◽  
Primitive Streak ◽  
Single Stage ◽  
Embryonic Cells ◽  
Chick Blastoderm ◽  
Almost All

In almost all embryos yolk becomes converted into cytoplasm. It has not previously been possible to describe in any detail the morphological changes involved in this process; indeed, when the yolk drops contained within embryonic cells are examined by light microscopy they seem to remain in much the same condition until they are suddenly used up. For this reason they have frequently been considered to be nothing but ‘inert, inactive’ stores of food. By using an electron microscope, however, it has been possible to trace some of the morphological changes which take place in the chick when intra-cellular yolk drops are converted into cytoplasm, and to show that these are not confined to a single stage of embryonic development. Moreover, the discovery of mitochondria within the yolk drops suggests that the yolk drops are not ‘inert’. The following stages have been examined: medium and long primitive streak (as defined by Waddington, 1932, and Abercrombie, 1950), head process, head fold, and 10–16 pairs of somites.

Apolar mode of gastrulation leads to the formation of polarized larva in a marine hydroid,Dynamena pumila

2021 ◽  
Author(s):  
Alexandra A. Vetrova ◽  
Tatiana S. Lebedeva ◽  
Aleena A. Saidova ◽  
Daria M. Kupaeva ◽  
Yulia A. Kraus ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Wnt Signaling ◽  
Body Axis ◽  
Cell Behavior ◽  
Axial Patterning ◽  
Molecular Patterning ◽  
Control Regulation ◽  
Morphological Polarity ◽  
Almost All ◽  
Canonical Wnt

AbstractBackgroundIn almost all metazoans examined to this respect, the axial patterning system based on canonical Wnt (cWnt) signaling operates throughout the course of development. In most metazoans, gastrulation is polar, and embryos develop morphological landmarks of axial polarity, such as blastopore under control/regulation from Wnt signaling. However, in many cnidarian species, gastrulation is morphologically apolar. The question remains whether сWnt signaling providing the establishment of a body axis controls morphogenetic processes involved in apolar gastrulation.ResultsIn this study, we focused on the embryonic development ofDynamena pumila, a cnidarian species with apolar gastrulation. We thoroughly described cell behavior, proliferation, and ultrastructure and examined axial patterning in the embryos of this species. We revealed that the first signs of morphological polarity appear only after the end of gastrulation, while molecular prepatterning of the embryo does exist during gastrulation. We have shown experimentally that inD. pumila,the morphological axis is highly robust against perturbations in cWnt activity.ConclusionOur results suggest that morphogenetic processes are uncoupled from molecular axial patterning during gastrulation inD. pumila. Investigation ofD. pumilamight significantly expand our understanding of the ways in which morphological polarization and axial molecular patterning are linked in Metazoa.

Diapause in Tarnished Plant Bug (Heteroptera: Miridae): Simulated Seasonal Occurrence in a Mississippi Population

2005 ◽  
Vol 40 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Eric J. Villavaso ◽  
Gordon L. Snodgrass
Keyword(s):  
Fat Body ◽  
Diapause Induction ◽  
Seasonal Occurrence ◽  
Lygus Lineolaris ◽  
Tarnished Plant Bug ◽  
Accessory Glands ◽  
Almost All

The incidence of diapause was determined in adult tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), reared in environmental cabinets that simulated daily field photoperiods occurring at Starkville, MS, during every month of the year. Temperature was held constant at 26.7°C. Photoperiod played a major role in diapause induction. Most nymphs (77.6 to 100%) hatching between 15 September and 15 February, about half of nymphs hatching in early March or early September, and few nymphs hatching between 15 March and 15 August (1.8 to 10.3%) developed into diapausing adults. Thus, early March and early September are transitional periods during which about half of newly-hatched nymphs will develop into diapausing adults. Between those periods, almost all bugs were reproductive, and outside of them, almost all were in diapause. Hypertrophied fat body coupled with underdeveloped accessory glands were used to classify male diapause, and hypertrophied fat body coupled with lack of mature eggs were used to classify female diapause.

Expression of tenascin during carcinogenesis and involution of hormone-dependent tissues

1994 ◽  
Vol 72 (11-12) ◽  
pp. 505-514 ◽  
Author(s):  
Günter Vollmer
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Embryonic Development ◽  
High Expression ◽  
Normal Adult ◽  
Tenascin C ◽  
Mesenchymal Tissue ◽  
Proliferative Endometrium ◽  
Almost All ◽  
Secretory Endometrium

Cytotactin/tenascin/hexabrachion, now referred to as tenascin-C (TN-C), is a hexameric glycoprotein of the extracellular matrix of mesenchymal tissue constituents. A high expression was found in embryonic development and during carcinogenesis of almost all organs. TN-C expression by the mesenchyme thereby appears to be induced by paracrine-acting, epithelial-derived (growth) factors. In normal adult organs there is little, if any, TN-C expression. In the human endometrium for instance, tenascin expression is low in the normal proliferative endometrium and undetectable in the normal secretory endometrium. In this paper, the appearance and expression of TN-C in hormone-dependent tissues, regressing hormone-dependent tissues, and tumors of the endometrium, breast and prostate is reviewed. Further, the regulation of TN-C expression is summarized and possible functions of TN-C during regression and carcinogenesis of hormone-dependent tissues are discussed.Key words: apoptosis, tenascin-C, extracellular matrix, prostate, mesenchyme, regression.

PHOSPHOMONOESTERASE ACTIVITY IN THE LIFE-CYCLE STAGES OF SCHISTOCERCA GREGARIA

1968 ◽  
Vol 100 (6) ◽  
pp. 649-655 ◽  
Author(s):  
S. N. H. Naqvi ◽  
Shahid H. Ashrafi ◽  
M. A. H. Qadri
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Embryonic Development ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Schistocerca Gregaria ◽  
Adult Males ◽  
First Instar ◽  
Almost All

AbstractThe acid and alkaline phosphatase activity was measured in the developing egg and in the alimentary canal of aging nymphs as well as adult males and females of different ages. Para-nitrophenol was used as colorimetric standard and disodium p-nitrophenyl phosphate as substrate. Activity was measured in terms of micromoles of p-nitrophenol liberated from the substrate as a result of enzyme action.Acid phosphatase activity was noticed to increase with the embryonic development and was higher than in the case of alkaline phosphatase. The alkaline phosphatase activity was lowest in the freshly laid egg, but increased more sharply than acid phosphatase during embryonic development.The activity of both the acid and alkaline phosphatases was highest in the first instar and declined gradually to the fifth instar. The activity of acid phosphatase was higher than alkaline phosphatase in all stages except the first instar where it was almost equal. The activity of both the enzymes was higher during the intermoulting period and declined at each moult indicating a hormone–enzyme relationship.In adults, activity of both the enzymes increased up to the maturation period after which the activity gradually decreased. Acid phosphatase activity was generally higher in males whereas alkaline phosphatase activity was generally higher in females. In almost all cases, the acid phosphatase activity was found to be higher than the alkaline phosphatase.

scholarly journals Vector Competence of Peruvian Mosquitoes for Two Orthobunyaviruses Isolated From Mosquitoes Captured in Peru

2020 ◽  
Author(s):  
M J Turell ◽  
D J Dohm ◽  
R Fernandez ◽  
T A Klein
Keyword(s):  
Salivary Gland ◽  
Amazon Basin ◽  
Vector Competence ◽  
Mosquito Species ◽  
Oral Exposure ◽  
Syrian Hamsters ◽  
Disseminated Infection ◽  
Transmitted Virus ◽  
Veterinary Importance ◽  
Almost All

Abstract We evaluated the potential for mosquitoes collected in the Amazon Basin, near Iquitos, Peru, to become infected with and transmit Murutucu (MURV) and Itaqui viruses (ITQV) (Order Bunyavirales, Family: Peribunyaviridae, Genus: Orthobunyavirus). Viremia levels in Syrian hamsters peaked 2 d after infection with either virus, and both viruses were highly lethal in hamsters with virtually all hamsters dying prior to 3-d postinfection. For almost all of the mosquito species tested some individuals were susceptible to infection and some developed a disseminated infection after oral exposure to either MURV or ITQV. However, only the Culex species (Culex (Culex) coronator Dyar and Knab [Diptera, Culicidae], Culex (Melanoconian) gnomatos Sallum, Huchings, and Ferreira [Diptera, Culicidae], Culex (Mel.) pedroi Sirivanakarn and Belkin [Diptera, Culicidae], and Culex (Mel.) vomerifer Komp [Diptera, Culicidae]) successfully transmitted virus by bite. However, even among these species, only about 37% of the individuals with a disseminated infection successfully transmitted these viruses, indicating a significant salivary gland barrier. Although little is known about the medical or veterinary importance of many members of the genus Orthobunyavirus, we have demonstrated that Culex spp. (Diptera, Culicidae) could be potential vectors.

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