scholarly journals Vacuolization of mucolipidosis type II mouse exocrine gland cells represents accumulation of autolysosomes

2011 ◽  
Vol 22 (8) ◽  
pp. 1135-1147 ◽  
Author(s):  
Marielle Boonen ◽  
Eline van Meel ◽  
Viola Oorschot ◽  
Judith Klumperman ◽  
Stuart Kornfeld

We previously reported that mice deficient in UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase (mucolipidosis type II or Gnptab −/− mice), the enzyme that initiates the addition of the mannose 6-phosphate lysosomal sorting signal on acid hydrolases, exhibited extensive vacuolization of their exocrine gland cells, while the liver, brain, and muscle appeared grossly unaffected. Similar pathological findings were observed in several exocrine glands of patients with mucolipidosis II. To understand the basis for this cell type–specific abnormality, we analyzed these tissues in Gnptab −/− mice using a combined immunoelectron microscopy and biochemical approach. We demonstrate that the vacuoles in the exocrine glands are enlarged autolysosomes containing undigested cytoplasmic material that accumulate secondary to deficient lysosomal function. Surprisingly, the acid hydrolase levels in these tissues ranged from normal to modestly decreased, in contrast to skin fibroblasts, which accumulate enlarged lysosomes and/or autolysosomes also but exhibit very low levels of acid hydrolases. We propose that the lysosomal defect in the exocrine cells is caused by the combination of increased secretion of the acid hydrolases via the constitutive pathway along with their entrapment in secretory granules. Taken together, our results provide new insights into the mechanisms of the tissue-specific abnormalities seen in mucolipidosis type II.

Author(s):  
Paul L. Krupa ◽  
Arya K. Bal ◽  
Gilles H. Cousineau

The fine structure of various gland cells and their secretory products was studied in the invasive stage (cercaria) of the platyhelminth parasite, Cryptocotyle lingua. Secretory granules or droplets occur in several different specialized cell types, but those that we call attention to here are found in the (1) surface cytoplasmic tegument or “cuticle”, (2) ducts of cephalic (penetration) glands, and (3) epithelial lining of the “excretory bladder”.The tegumental granules appear as numerous, membrane-bounded circular or oval profiles of uniform density (Fig. 1). They are scattered more or less randomly among mitochondria and other inclusion bodies of the tegument. Some of the longer granules, with a length to width ratio of about 7 to 1, have their long axes oriented perpendicularly to the surface plasma membrane of the parasite. In cercariae tested for acid hydrolases with sodium β-glycerophosphate in Barka and Anderson's modification of Gomori's medium, clumps of reaction product appear in the vicinity of the granules and elsewhere within the tegument, but not within the granules themselves. As granules that stain with periodic acid-Schiff, they are seen in certain subsurface gland cells as well as in the tegument under the light microscope.


2021 ◽  
Vol 27 ◽  
pp. 100747
Author(s):  
Parith Wongkittichote ◽  
Garland Michael Upchurch ◽  
Louis P. Dehner ◽  
Timothy Wood ◽  
Jorge L. Granadillo

Parasitology ◽  
1971 ◽  
Vol 62 (3) ◽  
pp. 355-360 ◽  
Author(s):  
Kenneth Smith ◽  
Eric Harness

A comparative study was made of defined regions of the alimentary tract of third-stage larvae of T. colubriformis and H. placei. The general organization of the tract was similar in both nematodes. The mouth, buccal cavity and oesophagus were lined with cuticle. Muscle cells, apical cells and gland cells were present in the oesophagus. In both species the gland cells contained secretory granules of similar morphology. The lumen of the intestine was ill-defined and apparently nonfunctional. Dense bodies observed in the intestinal cells differed in the two species.We are grateful to Dr D. W. Brocklesby for his help and advice. We would also like to thank Dr D. L. Lee and Dr W. G. MacMillan for helpful discussions.


2014 ◽  
Vol 26 (1) ◽  
pp. 52-53
Author(s):  
Chin-Chen Wen ◽  
Chun-Ying Weng ◽  
Meei-Ju Lin ◽  
Shao-Yin Chu
Keyword(s):  
Type Ii ◽  

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Sapna Sandal ◽  
Sunita Bijarnia Mahay ◽  
Deepti Gupta ◽  
Renu Saxena ◽  
Jyotsna Verma ◽  
...  

2009 ◽  
Vol 102 (5) ◽  
pp. 2834-2845 ◽  
Author(s):  
Andreas Husch ◽  
Moritz Paehler ◽  
Debora Fusca ◽  
Lars Paeger ◽  
Peter Kloppenburg

A diverse population of local interneurons (LNs) helps to process, structure, and spatially represent olfactory information in the insect antennal lobe. In Periplaneta americana, we identified two subtypes of nonspiking local interneurons (type II LNs) by their distinct morphological and intrinsic electrophysiological properties. As an important step toward a better understanding of the cellular mechanisms that mediate odor information processing, we present a detailed analysis of their distinct voltage-activated Ca2+ currents, which clearly correlated with their distinct intrinsic electrophysiological properties. Both type II LNs did not posses voltage-activated Na+ currents and apparently innervated all glomeruli including the macroglomerulus. Type IIa LNs had significant longer and thicker low-order neurites and innervated each glomerulus entirely and homogeneously, whereas type IIb LNs innervated only parts of each glomerulus. All type II LNs were broadly tuned and responded to odorants of many chemical classes with graded changes in the membrane potential. Type IIa LNs responded with odor-specific elaborate patterns of excitation that could also include “spikelets” riding on the depolarizations and periods of inhibition. In contrast, type IIb LNs responded mostly with sustained, relatively smooth depolarizations. Consistent with the strong active membrane properties of type IIa LNs versus type IIb LNs, the voltage-activated Ca2+ current of type IIa LNs activated at more hyperpolarized membrane potentials and had a larger transient component.


2000 ◽  
Vol 48 (6) ◽  
pp. 661 ◽  
Author(s):  
Johan Billen ◽  
Fuminori Ito ◽  
Christian Peeters

The third tarsomere of the hindlegs of both workers and queens of Nothomyrmecia macrops is almost entirely filled with a hitherto unknown exocrine gland (which does not occur in the closely related Myrmecia). Each of the approximately 30 secretory cells is connected to the outside via a duct cell. These open individually via large cuticular pores at the mesoventral side of the anterior part of the tarsomere. The diameter of the duct cells is narrow near the secretory cell, but gradually increases towards their opening site. The rounded secretory cells show a well developed Golgi apparatus and numerous clear vesicles. The function of this gland is not yet known, although its opening site may be indicative of the deposition of marking substances. At the mediodistal side of tarsomeres 2, 3 and 4 in the three pairs of legs, a glandular thickening of the epidermal epithelium occurs; this represents another novel exocrine structure in ants. This epithelial gland occurs in both Nothomyrmecia and Myrmecia.


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