Search results for "Exocrine gland"
showing 10 items of 29 documents
Cadmium binding proteins induced in exposed freshwater crayfish Procambarus clarkii.
1989
This work describes results on the characterization of cadmium binding proteins (Cd-BPs) obtained from cadmium exposed freshwater crayfish Procambarus clarkii. After acclimation to laboratory conditions, induction of Cd-BPs was achieved by water exposure at a concentration of 100 micrograms Cd/L during 2, 15, and 30 d. In accordance with the method followed by Engel and Brouwer, in each case two midgut glands were minced and homogenized in Tris-HC1 buffer with PMSF to prevent protease activity and DTT to maintain reducing conditions. The homogenate was centrifuged, heat treated, applied to a column of Sephadex G-75, and eluted with the same buffer (pH 8.6). Absorbances of the fractions coll…
Morphology and ultrastructure of paired prototergal glands in the adult rove beetle Philonthus varians (Coleoptera, Staphylinidae)
2002
Abstract Philonthus and other genera of Philonthina possess a pair of prototergal glands located in the first abdominal tergum and hidden at rest by hind wings and elytra. In Philonthus varians they occupy the whole length of the tergum and form a pouch-like invaginated reservoir with a scaly glandular zone and a smooth outlet. A grille of long setae covers the opening of each gland. The fine structure of these glands is given for the first time. Three types of cells are found in the glandular epithelium. Epidermal cells underlie the cuticular scales, numerous class 1 secretory cells open in the centre of calyces made of finger-like processes of the cuticle, and class 3 cells are connected …
Morphology of the male and female tergal glands of the woodroach Cryptocercus punctulatus (Insecta, Dictyoptera)
1989
Males and females of Cryptocercus punctulatus possess tergal glands which differ in position, size, morphology, and chemical composition of their secretions. Ultrastructural studies reveal the presence of class 1 and class 3 glandular units interspersed throughout the glands; class 3 glandular units are 30 times as numerous as in the female, but no cytological difference was found between the sexes. The morphology of the tergal glands is characterized by the occurrence of a subcuticular space reservoir, a dense tracheal system, and a thick collagenous layer instead of the typical basement membrane. Comparison with the termite abdominal gland system indicates a great similarity in the fine s…
The exocrine glands of Dysdercus cingulatus (Heteroptera, Pyrrhocoridae): Morphology and function of nymphal glands.
2018
The exocrine glandular system of the nymphs and the adults of Dysdercus cingulatus were studied. The D. cingulatus nymphs present 3 dorso-abdominal glands (lying under the 3rd, 4th, and 5th abdominal terga) and a pair of dorso-lateral pygidial glands on the pygidium (tergum 8). Histological and ultrastructural studies show that the upper and lower walls of the dorso-abdominal glands differ in structure; 3 types of cells were described: epidermal cells, unicellular secretory cells, and multicellular secretory units. Each of these exocrine glands plays an important part in the behavior of the nymphs (gregariousness, alarm, defense). The morphology of the various glands is discussed, and the c…
Molecular characterization of a male-specific glycosyl hydrolase, Lma-p72, secreted on to the abdominal surface of the Madeira cockroach Leucophaea m…
2003
0264-6021 (Print) Journal Article Research Support, Non-U.S. Gov't; The epicuticular surface protein Lma-p72 is specific to the abdominal secretions of Leucophaea maderae (Madeira cockroach) adult males. Natural Lma-p72 was purified and the complete cDNA sequence determined by reverse-transcription PCR using primers based on Edman degradation fragments. Northern blot and in situ hybridization analyses showed that Lma-p72 was expressed in the tergal and sternal glands. Sequence alignment indicates that Lma-p72 is closely related to the family 1 glycosyl hydrolases (EC 3.2.1). Native Lma-p72 was proved to be active in the abdominal secretions and exhibit a beta-galactosidase-like activity. Ho…
Fibroblast Growth Factor 21 (FGF21) Protects against High Fat Diet Induced Inflammation and Islet Hyperplasia in Pancreas
2015
Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic regulator expressed in multiple tissues including liver and adipose tissue. Although highest levels of expression are in pancreas, little is known about the function of FGF21 in this tissue. In order to understand the physiology of FGF21 in the pancreas, we analyzed its expression and regulation in both acinar and islet tissues. We found that acinar tissue express 20-fold higher levels than that observed in islets. We also observed that pancreatic FGF21 is nutritionally regulated; a marked reduction in FGF21 expression was noted with fasting while obesity is associated with 3–4 fold higher expression. Acinar and islet c…
Production, regeneration and biochemical precursors of the major components of the defensive secretion of Eurycotis floridana (Dictyoptera, polyzoste…
2000
0965-1748 (Print) Journal Article; The defensive secretion of the cockroach Eurycotis floridana contains three main components, (E)-2-hexenal, (E)-2-hexenol and (E)-2-hexenoic acid, which represented about 98% of the organic phase. The quantity of the aldehyde, alcohol, and acid present in the defensive secretion increased rapidly for 60 days from the imaginal moult. Following artificial discharge, the males were able to regenerate their initial volume of secretion over a 30 day period. To investigate the possible routes of biosynthesis of the three components, E. floridana was injected with 14C-labeled fatty acids and acetate, and the incorporation of 14C into the three components were qua…
Automatic classification of tissues on pelvic MRI based on relaxation times and support vector machine
2019
International audience; Tissue segmentation and classification in MRI is a challenging task due to a lack of signal intensity standardization. MRI signal is dependent on the acquisition protocol, the coil profile, the scanner type, etc. While we can compute quantitative physical tissue properties independent of the hardware and the sequence parameters, it is still difficult to leverage these physical properties to segment and classify pelvic tissues. The proposed method integrates quantitative MRI values (T1 and T2 relaxation times and pure synthetic weighted images) and machine learning (Support Vector Machine (SVM)) to segment and classify tissues in the pelvic region, i.e.: fat, muscle, …
Molecular characterization of a new adult male putative calycin specific to tergal aphrodisiac secretion in the cockroach Leucophaea maderae
2001
0014-5793 (Print) Journal Article Research Support, Non-U.S. Gov't; Lma-p18 is an epicuticular surface protein specific to the tergal gland aphrodisiac secretion of Leucophaea maderae adult males. Native Lma-p18 was purified and the complete cDNA sequence was determined by RT-PCR using primers based on Edman degradation fragments. Northern blot and in situ hybridization analyses showed that Lma-p18 is expressed exclusively in the anterior part of male tergal gland, which is exposed only during sexual behavior. Sequence analysis indicated that Lma-p18 belongs to the calycin superfamily and is very similar to Lma-p22, the first known male-specific tergal protein in L. maderae. Lma-p18 and Lma…
Effects of feminizing microsporidia on the masculinizing function of the androgenic gland in Gammarus duebeni
2013
Feminizing parasites enhance their vertical transmission to the host offspring by converting genetic male hosts into phenotypic females. Crustacea are the only invertebrates where sexual differentiation is controlled by a specialised endocrine organ, the androgenic gland, rather than by the gonads. We showed that a feminizing microsporidian Microsporidium sp. inhibits androgenic gland differentiation. We investigated the effect of Microsporidium sp. and a second feminizing microsporidium, Nosema granulosis, on the masculinizing function of the androgenic gland in Gammarus duebeni. Androgenic gland implants had a masculinizing effect on the sexual characteristics and sexual behaviour of reci…