AcPase Activity Research Articles

Interaction of phosphorus and GA3 improved oilseed flax grain yield and phosphorus-utilization efficiency.

Phosphorus nutrition and hormone concentration both affect crop yield formation. Ascertaining the interaction of phosphorus and GA3 has a synergistic effect on the grain yield and phosphorus utilization efficiency of oilseed flax in dryland. It is extremely important for improving grain yield and phosphorus utilization efficiency. A field experiment was conducted in 2019 and 2020 at the Dingxi Oil Crops Test Station to investigated the effects of phosphorus, gibberellin (GA3), and their interaction on the grain yield and phosphorus-utilization efficiency of oilseed flax plants. Phosphorus fertilizer was applied at three levels (0, 67.5, 135 kg P2O5·ha-1) and GA3 was also sprayed at three concentrations (0, 15, and 30 mg·L-1). The results showed that application of 67.5kg P2O5·ha-1 reduced leaves acid phosphatase (ACPase) activity, but increased phosphorus accumulation throughout the growth period, the 1000-kernel weight (TKW), and the number of grains per capsule. Spraying GA3 significantly increased the leaves ACPase activity, phosphorus accumulation after anthesis and its contribution to grain, phosphorus-utilization efficiency, the number of capsules per plant, and TKW. The phosphorus accumulation at the anthesis, kernel, and maturity stages under the treatment of fertilizing 67.5kg P2O5·ha-1 and spraying 30 mg·L-1 GA3 were increased by 56.06%, 73.51%, and 62.17%, respectively, compared with the control (no phosphorus, no GA3). And the phosphorus accumulation after anthesis and its contribution to grain also increased. 67.5kg P2O5·ha-1 combined with 30 mg·L-1 GA3 and 135kg P2O5·ha-1 combined with 15 mg·L-1 GA3 both significantly increased grain yield of oilseed flax, reaching 1696 kg·ha-1 and 1716 kg·ha-1 across two years, respectively. And there was no significant difference between them. However, the former treatment significant increased the apparent utilization rate, agronomic utilization rate, and partial productivity of phosphorus. The interaction between phosphorus and GA3 was significant for grain yield. Therefore, the application of 67.5kg P2O5·ha-1 in combination with 30 mg·L-1 GA3 is an effective fertilization approach for enhancing oilseed flax growth and grain yield in the experiment region and other similar areas.

Mycorrhizal fungus Serendipita indica-associated acid phosphatase rescues the phosphate nutrition with reduced arsenic uptake in the host plant under arsenic stress

Symbiotic interactions play a vital role in maintaining the phosphate (Pi) nutrient status of host plants and providing resilience during biotic and abiotic stresses. Serendipita indica, a mycorrhiza-like fungus, supports plant growth by transporting Pi to the plant. Despite the competitive behaviour of arsenate (AsV) with Pi, the association with S. indica promotes plant growth under arsenic (As) stress by reducing As bioavailability through adsorption, accumulation, and precipitation within the fungus. However, the capacity of S. indica to enhance Pi accumulation and utilization under As stress remains unexplored. Axenic studies revealed that As supply significantly reduces intracellular ACPase activity in S. indica, while extracellular ACPase remains unaffected. Further investigations using Native PAGE and gene expression studies confirmed that intracellular ACPase (isoform2) is sensitive to As, whereas extracellular ACPase (isoform1) is As-insensitive. Biochemical analysis showed that ACPase (isoform1) has a Km of 0.5977 µM and Vmax of 0.1945 Unit/min. In hydroponically cultured tomato seedlings, simultaneous inoculation of S. indica with As on the 14thday after seed germination led to hyper-colonization, increased root/shoot length, biomass, and induction of ACPase expression and secretion under As stress. Arsenic-treated S. indica colonized groups (13.33 µM As+Si and 26.67 µM As+Si) exhibited 8.28–19.14 and 1.71–3.45-fold activation of ACPase in both rhizospheric media and root samples, respectively, thereby enhancing Pi availability in the surrounding medium under As stress. Moreover, S. indica (13.33 µM As+Si and 26.67 µM As+Si) significantly improved Pi accumulation in roots by 7.26 and 9.46 times and in shoots by 4.36 and 8.85 times compared to the control. Additionally, S. indica induced the expression of SiPT under As stress, further improving Pi mobilization. Notably, fungal colonization also restricted As mobilization from the hydroponic medium to the shoot, with a higher amount of As (191.01 ppm As in the 26.67 µM As+Si group) accumulating in the plant's roots. The study demonstrates the performance of S. indica under As stress in enhancing Pi mobilization while limiting As uptake in the host plant. These findings provide the first evidence of the As-Pi interaction in the AM-like fungus S. indica, indicating reduced As uptake and regulation of PHO genes (ACPase and SiPT genes) to increase Pi acquisition. These data also lay the foundation for the rational use of S. indica in agricultural practices.

Determination of ANAE and AcP-ase Positivity in the Peripheral Blood of Pregnant Women with Hypothyroidism

Objective: Pregnancy is a stress factor for thyroid functions. The most commonly observed thyroid disorder is hypothyroidism. The immune system is affected both by pregnancy and hypothyroidism. This disorder causes a decrease in humoral and cell-mediated immune responses. This study was aimed at the comparison of alpha-naphthyl acetate esterase- and acid phosphatase-positive T lymphocyte distribution between healthy and hypothyroid pregnant women. Methods: Blood samples were taken from healthy and hypothyroid pregnant women between June-December 2016. The sampled subjects included 10 healthy non-pregnant women (HC), 10 healthy pregnant women (HP), and 30 hypothyroid pregnant women in different trimesters of pregnancy (HpPTRI, HpPTRII and HpPTRIII). From each of these groups, six smears were prepared and histologically stained for ANAE and AcP-ase activity and with May Grünwald-Giemsa. Results: The lowest ANAE- and AcP-ase-positive T lymphocyte percentages were detected in Group HP, and these percentages were higher in the hypothyroid pregnant groups, compared to Group HC (P<0.05). Based on PBL counts, the lowest lymphocyte and highest neutrophil leukocyte rates were detected in the pregnant groups. Hypothyroid pregnant women were determined to have monocytic leukocyte rates lower than those of Group HC and Group HP (P<0.05). Conclusions: In this study, it was concluded that significant alterations had occurred in the PBL and ANAE- and AcP-ase-positive T lymphocyte counts of Group HP and the hypothyroid pregnant groups. These findings provide important data about the immunity of hypothyroid pregnant women.

Effects of long term oral acrylamide administration on alpha naphthyl acetate esterase and acid phosphatase activities in the peripheral blood lymphocytes of rats

ABSTRACTAcrylamide is an important industrial chemical; it also is formed in starch-rich foodstuffs during baking, frying and roasting. Most acrylamide exposure occurs by ingestion of processed foods. We investigated possible immunotoxic effects of extended administration of low doses of acrylamide in rats. To do this, we measured alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACP-ase) activities in peripheral blood lymphocytes. Male and female weanling Wistar rats were administered 2 or 5 mg acrylamide/kg/day in drinking water for 90 days. Peripheral blood was sampled at the end of the administration period. We found ANAE staining in eosinophils and T-lymphocytes, but not in monocytes, platelets, B-lymphocytes and neutrophils. ACP-ase was found in B-lymphocytes. We found a significant reduction of the ratio of ANAE:ACP-ase in lymphocytes of the experimental animals compared to controls. We found no statistically significant differences between the doses or sexes. We found that acrylamide ingested in processed foods might affect the immune system adversely by decreasing the population of mature T- and B-lymphocytes.

Ultra-structural, histo-chemical and histo-enzymic activities in the large intestine of developing Guinea fowl

The ultrastructural, histochemical and histoenzymic activities in the large intestine of the post-hatch Guinea fowl were studied. Guinea fowl of days 1, 7, 15, 30, 90 and 180 were used. The distribution of histochemically active compounds and enzymes were correlated with age. The distributions of enzymes and histochemically reactive substance within the cytoplasm of intestinal epithelial cells have shown that the cytochemical pattern of the mature intestinal absorptive cell is the reflection of both its structural arrangement and its highly specialized function. The brush border showed a mild to moderate reaction with PAS which was resistant to diastase. The apical microvillus coating of glycocalyx, was very thin but it stained strongly with the Alcian Blue thus revealing the presence of acid mucopolysaccharides. The activity of AKPase, ACPase and lipase were observed in the surface epithelium and crypts which increased with the advancement of the age. Columnar cells of the villi and glycocalyx coat of the brush border of all segments of the large intestine showed a mild positive reaction for lipase activity. On ultra-structural study, the epithelial cells of large intestine were tall columnar in shape. They possessed well developed striated border and terminal web. The presence of numerous long micro-villi covered with glycocalyx.

Histology and Histochemistry of Interstitial Tissue of Testes in Mountain (Gaddi) Goats-A Postnatal Developmental Study

Testicular tissues obtained from 30 mountain (Gaddi) goats ranging from newborn to > 60 months age divided into 3 age groups viz; prepubertal (neonatal to 18 months to 60 months) with at least 10 animals in each group were studied for histological and histochemical changes in their interstitium at various stage of development. The loose connective tissue comprised of various mesenchymal cells, fibroblasts, undifferentiated and differentiated Leydig cells-in various stages of development with capillaries and lymphatics filled up the interstices between the sex cords/seminiferous tubules being more juvenile in neonates (with mesenchymal and young fibroblast cells) and mature (fibroblasts, fibrocytes and Leydig cells) in older animals. The latter also showed mononuclear cell infiltration as an autoimmune reaction of the ageing testicles. It contributed 65% of testicular tissues in neonates but 13–15% in pubertal and slightly less in postpubertal animals. Among the various cell types, Leydig cells were mostly PAS reactive. The Alcian Blue reaction was inconclusive, colloidal iron stained them mildly to moderately in neonates and prepubertal, moderately to strongly in pubertal and postpubertal groups. BPB reaction for protein and Feulgen for DNA was also strongly represented. Sudan black-B and oil red-O revealed an increasing trend with age. AKPase and ACPase activity was moderate in the Leydig cells.

Influence of Sudden Thermal Stresses on Growth Rate and Enzymatic Identification of Bombyx mori L. Larvae

Article History The purpose of this study is to determine the impact of different thermal stresses for different periods on univoltine Bombyx mori embryos and grown larvae in terms of larval growth rates, effective rate of rearing and the enzymatic proliferation of larval haemolymph. Egg groups was exposed to different temperatures; 0°C for one hour, 0°C for two hours, 40°C for one hour and 40°C for two hours, followed by 2 hours recovery at room temperature in addition to a control group, the same was applied to the grown larvae. Larval haemolymph of tested groups were subjected to enzyme electrophoretic analysis by native polyacrylamide gel electrophoresis (PAGE) for phosphatases and esterases identification. Exposure to sudden thermal stress of 0°C for one hour at larval stage recorded the highest growth rate. The sudden thermal stresses did not significantly affect the effective rate of rearing. However, thermal stresses increased ACPase and ALKPase activities and decreased α and β esterases activities comparing to control. These results suggest applying sudden heat thermal proteins in breeding strategy for inducing robustness in productive breeds.

A Study of Peripheral Blood in Hedgehogs in Turkey

The aim of this study was to determine diameters of blood cells, differential counts of peripheral blood leukocytes, alpha-naphthyl acetate esterase (ANAE), acid phosphatase (ACP-ase) activity of some leukocyte types, and enzymatic positivity percentages of peripheral blood lymphocytes in two hedgehogs species, Hemiechinus auritus, the long-eared hedgehog, and Erinaceus concolor, the southern white-breasted hedgehog. Air-dried peripheral blood smears were stained with May-Grünwald-Giemsa stain. ANAE and ACP-ase were stained in glutaraldehyde-acetone-fixed smears. ANAE-positive lymphocytes displayed a dot-like positivity pattern characterized with 1-5 reddish brown cytoplasmic granules, whereas ACP-ase positive lymphocytes displayed a dot-like positivity pattern characterized with 1-3 pinkish cytoplasmic granules. Monocytes gave a diffuse and strong reaction while neutrophils displayed a weak positive reaction for ANAE and ACP-ase. No difference was observed in mean diameters of peripheral blood cells of these species. It was found that lymphocytes made up the majority (64.3% and 65.5%) of leukocytes, followed by neutrophils (23.9% and 23.3%), eosinophils (9.0% and 7.6%), monocytes (1.8% and 2.3%), and basophils (1.0% and 1.3%) in H. auritus and E. concolor, respectively. Mean ANAE positivity oflymphocytes was 36.6% and 51.3% and ACP-ase positivity was 32.1% and 37.5% for H. auritus and E. concolor, respectively. The ANAE positivity of lymphocytes in E. concolor was significantly (P < 0.05) higher than that of H. auritus.

Localization of acid phosphatase activity in the apoplast of root nodules of pea (Pisum sativum)

Changes in the activity of acid phosphatase (AcPase) in the apoplast of pea root nodule were investigated. The activity was determined using lead and cerium methods. The results indicated a following sequence of AcPase activity appearance during the development of the infection thread: 1) low AcPase activity appears in the outer part of cells of symbiotic bacteria; 2) bacteria show increased AcPase activity, and the enzyme activity appears in the thread walls; 3) activity exhibits also matrix of the infection thread; 4) bacteria just before their release from the infection threads show high AcPase activity; 5) AcPase activity ceases after bacteria transformation into bacteroids. The increase in bacterial AcPase activity may reflect a higher demand for inorganic phosphorus necessary for propagation of the bacteria within the infection threads and/or involved in bacteria release from the infection threads.

Potentilla fulgens (Family Rosaceae), a medicinal plant of north-east India: a natural anthelmintic?

The cestode parasite, Raillietina echinobothrida and the trematode, Gastrothylax crumenifer were exposed to the ethanolic root peel extract of Potentilla fulgens, an antiparasitic local medicinal plant of Meghalaya, India, to evaluate the anthelmintic efficacy of the plant. The parasites were incubated in 1, 5, 10, 20, 50 and 100mg crude alcoholic extract per ml of phosphate buffered saline (PBS) at a temperature of 37±1°C. Paralysis and death were observed at 2.00±0.05 and 2.80±0.06h for the cestode and 1.21±0.06 and 2.18±0.04h for the trematode parasites at the highest test concentration of the plant extract. The commercial anthelmintic, Praziquantel (PZQ) showed higher activity at the tested concentration (0.02mg/ml). To further investigate the efficacy of the plant extract, vital tegumental enzymes of the parasite viz. Acid phosphatase (AcPase), Alkaline phosphatase (AlkPase) and Adenosine triphosphatase (ATPase) were studied. Quantitatively, the total enzyme activity of AcPase, AlkPase and ATPase was found to be reduced significantly by 69.20, 66.43 and 29.63% for R. echinobothrida and 47.96, 51.79 and 42.63% for G. crumenifer, respectively compared to the respective controls; histochemical study also showed reduction in the visible staining of the enzymes. The reference drug, PZQ also showed more or less similar effect like that of the plant extract. The result suggests that phytochemicals of P. fulgens have anthelmintic potential.

Ultrastructure of the pericardial cells in the 4th and 5th instars and AcPase activity of proteinic granules in the silkworm, Bombyx mori

Ultrastructure of the pericardial cells in the 4th and 5th instars and AcPase activity of proteinic granules in the silkworm, Bombyx mori

Ameliorative effect of curcumin on hepatotoxicity induced by chloroquine phosphate

India is one of the most endemic areas, where malaria predominates and its control has become a formidable task. Chloroquine phosphate (CQ) on account of its rapid action on blood schizontocide of all the malarial parasite strains has become the most widely prescribed drug for prophylaxis and treatment of malaria. Toxicity of CQ is most commonly encountered at therapeutic and higher doses of treatment. Thus, the present study was undertaken to evaluate the protective effect of Curcumin, a herbal antioxidant obtained from Curcuma longa, on hepatic biochemical and histopathological status of CQ induced male mice. Swiss albino male mice were administered oral doses of CQ (100 mg/kg body wt., 200 mg/kg body wt. and 300 mg/kg body wt.) and CQ + curcumin (300 mg/kg body wt. + 80 mg/kg body wt.) for 45 days. A withdrawal of high dose treatment for 45 days was also studied. Administration of CQ brought about a significant decrease in Protein content with a decline in SDH, ATPase and ALKase activities, whereas ACPase activity was found to be significantly increased following CQ treatment. Antioxidant enzyme SOD registered a significant reduction as opposed to TBARS which was found to be elevated in a significant manner in the CQ treated groups as compared to control. Gravimetric indices (body weight and organ weight) declined significantly following CQ treatment. Administration of curcumin exhibited significant reversal of CQ induced toxicity in hepatic tissue. Protein content, SDH, ATPase, ALKase, ACPase, SOD, TBARS, body weight and organ weight were found to be comparable to that of control group after curcumin administration. Thus, obtained results led us to conclude the curative potential of curcumin against CQ induced hepatotoxicity.

Efficiency of acid phosphatases secreted from the ectomycorrhizal fungus Hebeloma cylindrosporum to hydrolyse organic phosphorus in podzols

Ectomycorrhizal fungi may improve the phosphate nutrition of their host plants by secreting, into the soil solution, acid phosphatases (AcPases) able to release orthophosphate (Pi) from soil organic phosphorus (Po). Using cation-exchange chromatography, we separated four fractions with AcPase activity secreted by the ectomycorrhizal fungus Hebeloma cylindrosporum grown in a pure culture under P-starved conditions. Each AcPase active fraction displayed strong ability in vitro to hydrolyse a wide range of phosphate monoesters, but none of them efficiently hydrolysed phytate. Their efficiency to release Pi from soil NaHCO(3)-extractable Po was studied in a sandy podzol used intact or autoclaved. Soils were collected in a 15-year-old Pinus pinaster stand, receiving regular fertilization or not. Autoclaving increased the NaHCO(3)-extractable Po concentrations by 55% in unfertilized and by 32-43% in fertilized soils. The efficiency of each AcPase fraction was affected significantly by the soil fertilization regime and the soil treatment (intact vs. autoclaved). The proportion of labile Po enzyme ranged from 0% to 11% and 14% to 48% after 1 h of incubation in bicarbonate solutions extracted from intact and autoclaved soils, respectively. This work suggests that AcPases secreted from H. cylindrosporum could be efficient in recycling Po pools from soil microorganisms that may be delivered by soil autoclaving.

Anthelmintic efficacy of ethanolic shoot extract of Alpinia nigra on tegumental enzymes of Fasciolopsis buski, a giant intestinal parasite.

Ethanolic shoot extract of Alpinia nigra, a traditionally used anthelmintic medicinal plant among the Tripuri tribes of north-east India, was tested in vitro to determine its anthelmintic efficacy in gastrointestinal trematode Fasciolopsis buski, using alterations in the activity of vital tegumental enzymes viz. acid phosphatase (AcPase), alkaline phosphatase (AlkPase) and adenosine triphosphatase (ATPase). Live adult F. buski treated in vitro with different concentrations of the plant extract showed significant decline in the visible stain histochemically and enzyme activities. Quantitatively, the total enzyme activity of AcPase, AlkPase and ATPase was found to be reduced by 45, 41 and 43%, respectively compared to the control. The reference drug, praziquantel also showed more or less similar effect like that of the plant extract. The results suggest that the tegumental enzymes of the parasite may be an important target of action for active component(s) of A. nigra, which appears to act transtegumentally.

Beneficial Effects of Cocoa in Perivascular Mato Cells of Cerebral Arterioles in SHR-SP (Izm) Rats

As previously reported, the cerebral arterioles are surrounded by unique perivascular Mato cells. They contain many inclusion bodies rich in hydrolytic enzymes, and have strong uptake capacity. They are thus considered scavenger cells of vascular and neural tissues in steady-state. In this study, employing hypertensive SHR-SP (Izm) rats, the viability of Mato cells was investigated. In hypertensive rats, the capacity for uptake of horse radish peroxidase (HRP) and the activity of acid phosphatase (ACPase) of Mato cells were markedly reduced, and on electron-microscopic examination Mato cells were found to include heterogeneous contents and appeared electron-dense and degenerated. Vascular cells exhibited some signs of pathology. However, in hypertensive rats fed chow containing 0.25% cocoa, the uptake capacity and ACPase activity of Mato cells for HRP were enhanced, and on electron-microscopic examination Mato cells appeared healthy, with mitochondria with nearly normal profiles. Signs of pathology in vascular cells were also decreased. Superoxides may impair Mato cells and vascular cells.

RELATIONSHIPS AMONG SPECIFIC GROWTH, SECRETED ACID PHOSPHATASE, INTRACELLULAR AND TOTAL INORGANIC PHOSPHORUS CONCENTRATION IN CHLORELLA FUSCA CULTURED UNDER VARIOUS LEVELS OF NA2HPO4

The relationships among specific growth rates, intracellular inorganic phosphate (Pi) and total phosphorus concentrations and specific activities of acid phosphatase (acPase) were studied on the green unicellular alga Chlorella fusca at 1.0, 15.0 and 30.0 µM Na2HPO4. The specific growth, the intracellular Pi and total phosphorus concentration increased with increasing Na2HPO4 levels. The acid phosphatase activity was inversely correlated with the specific growth rate, the total P concentrations and the intracellular inorganic concentrations. The P-deficiency induction of acPase activity is related to a decrease in P-availability in Chlorella fusca.

Effects of Hg and Cu on the activities of soil acid phosphatase

Comparative study on the activity and kinectic properties of acid phosphatase (ACPase) of three soils amended with Hg and Cu at constant temperature and humidity was carried out. The results indicated that the inhibition on ACPase of the three sample soils by Hg and Cu varied with the content of soil organic matter and pH, where, Soil 1 was the most seriously contaminated due to its lowest content of organic matter and the lowest pH among three samples, Soil 2 took the second place, and Soil 3 was the least contaminated. Except Soil 3, the activity of soil ACPase tended to increase along with the contact time under the same type and the same concentration of heavy metal. In particular the Vmax values of ACPase in all three samples decreased with increasing Hg and Cu concentration, whereas the Km values were affected weakly. According to the change of Vmax and Km values, Cu and Hg had the same inhibition effect on soil ACPase. Both of them may be a type of compound of non-competitive and anti-competitive inhibition. Statistic analyses indicated that activities of soil ACPase and Vmax values could serve as bioindicator to partially denote the heavy metal Hg and Cu contamination degree.

Morphofunctional changes in Leydig cells throughout the continuous spermatogenesis of the freshwater teleost fish, Serrasalmus spilopleura (Characiformes, Characidae): an ultrastructural and enzyme study

The freshwater fish Serrasalmus spilopleura (piranha) has a continuous type of reproduction; gametes are constantly produced and released during the reproductive cycle. The testes do not undergo seasonal morphological changes but exhibit two constant regions throughout the year: the medullar region (involved with spermatogenesis) and the cortical region (involved with spermiation and sperm storage). We have evaluated the ultrastructure of the Leydig cells and the activity of 3beta-HSD (an essential enzyme related to steroid hormone biosynthesis) and acid phosphatase (AcPase; lysosomal marker enzyme) in these two regions. The activity of 3beta-HSD is stronger in the medullar region, and the Leydig cells in this region have a variety of cytological features that reflect differences in hormone synthesis and/or that could be linked to steroidogenic cells under various degrees of hormonal activity. In the cortical region, 3beta-HSD activity is weak and the Leydig cells exhibit signs of degeneration, as confirmed by their ultrastructure and intense AcPase activity. These degenerative signs are indicative of cytoplasmic remodelling to degrade steroidogenic enzymes, such as 3beta-HSD, that could lead to senescence or even to autophagic cell degeneration. S. spilopleura thus constitutes an interesting model for increasing our understanding of steroidogenesis control in freshwater teleost fish.

Localization of acid phosphatase activity in the apoplast of pea (Pisum sativum L.) root nodules grown under phosphorus deficiency

ACPase activity was localized in the apoplast of pea root nodules under phosphorus deficiency. Pea plants (Pisum sativum L. cv. Sze ciotygodniowy) where inoculated with Rhizobium leguminosarum bv. viciae 248 and were cultured on nitrogen-free medium with phosphate (−N/+P) or phosphate-deficient (−N/−P) one. In comparison with control nodules, P-deficient nodules showed the increase of ACPase activity in plant cell walls and the infection threads. The increase in bacterial ACPase activity under P-deficiency may reflect higher demand for inorganic phosphorus that is necessary for bacteria multiplication within the infection threads. The increase of ACPase activity in nodule apoplast under P stress may enlarge the availability of phosphate for plant and bacteria.

Glycosylation and sorting pathways of lysosomal enzymes in mussel digestive cells

Our aim was to contribute to the understanding of the synthesis, maturation and activation of lysosomal enzymes in an invertebrate cellular model: the endo-lysosomal system (ELS) of mussel digestive cells. The activities of 5'-nucleotidase (AMPase), arylsulphatase (ASase) and acid phosphatase (AcPase), which are transported towards acidic compartments as membrane proteins, were localised by enzyme cytochemistry. AcPase activity was found within large heterolysosomes and residual bodies. ASase was located in endosomes, endolysosomes and heterolysosomes. AcPase and ASase activities were recorded within small vesicles and cisterns of the trans-Golgi network. Conversely, AMPase activity was primarily found in microvilli and apical vesicles and, less conspicuously, in lysosomes and the cis-side of the Golgi and the cis-Golgi network (CGN). In order to understand the processes of synthesis and maturation of these lysosomal enzymes, selected glycoconjugates were localised after lectin cytochemistry. N-acetylglucosamine, mannose and fucose residues were almost ubiquitous in the ELS, as were galactose residues, which were apparently less abundant. N-acetylglucosamine residues occurred in the inner membrane co-localised with mannose residues within the lysosomal and pre-lysosomal acidic compartments. Based on these results, glycosylation and sorting pathways are proposed for both soluble and membrane enzymes. Unlike in mammalian cells, O-glycosylation is fully completed in the CGN, mannose addition in N-glycosylation extends beyond the CGN and galactose addition is fully achieved at the intermediate side. Sorting of soluble lysosomal enzymes, as in crustaceans, is mediated by the indirect transport of membrane-linked proteins with GlcNAc1-P6Man residues that are removed in endolysosomes and heterolysosomes.