RESUMO

Copper (Cu) mining has to address a critical environmental issue related to the disposal of heavy metals and metalloids (HMs). Due to their deleterious effects on living organisms, Cu and arsenic (As) have gained global attention, and thus their monitoring in the environment is an important task. The aims of this study were: 1) to evaluate the alteration of soil enzyme activities (EAs) and soil microbial functional diversity with Cu/As contamination, and 2) to select the most reliable biochemical indicators of Cu/As contamination. A twelve-week soil experiment was performed with four increasing levels of Cu, As, and Cu/As from 150/15 to 1000/100 mg Cu/As kg-1. Soil enzyme activities and soil community-level physiological profile (CLPP) using MicroResp™ were measured during the experiment. Results showed reduced EAs over time with increasing Cu and Cu/As levels. The most Cu-sensitive EAs were dehydrogenase, acid phosphatase, and arylsulfatase, while arginine ammonification might be related to the resilience of soil microbial communities due to its increased activity in the last experimental times. There was no consistent response to As contamination with reduced individual EAs at specific sampling times, being urease the only EA negatively affected by As. MicroResp™ showed reduced carbon (C) substrate utilization with increasing Cu levels indicating a community shift in C acquisition. These results support the use of specific EAs to assess the environmental impact of specific HMs, being also the first assessment of EAs and the use of CLPP (MicroResp™) to study the environmental impact in Cu/As contaminated soils.

Assuntos

RESUMO

The mammalian epididymis is an organ particularly rich in acid hydrolases, consistent with a developed lysosomal apparatus. However, some of these enzymes could also play a role in an extracellular environment, since they are actively secreted by the epithelium. In this study the authors measured the activity of five acid hydrolases distributed between the epithelium, fluid, small vesicles, and spermatozoa of the rat cauda epididymis in adult rats, and compared with that distribution under conditions of deprivation of luminal testosterone and testicular compounds (hemicastration). Lysosomal enzymes are differently compartmentalized in rat cauda epididymis. Most of beta-galactosidase (beta-GAL) and aryl sulfatase (approximately 70%) were found in soluble form within the fluid. Some 60% of N-acetyl-beta-D-glucosaminidase (beta-NAG) and alpha-mannosidase (alpha-MAN) become transiently bound to sperm, and beta-glucuronidase (beta-GLU) was mostly concentrated in the epithelium. After remotion of testis this distribution changed, as the retention of alpha-MAN, beta-GAL, beta-GLU, and beta-NAG by the epididiymal tissue increased. The increase of beta-GLU followed an increase of synthesis of the enzyme. The distribution of enzymes in the epididymis from the contralateral side was similar to that in normal rats. The different roles for each enzyme in the epididymis are discussed.

Assuntos

Assuntos

RESUMO

The activity of five acid hydrolases in the adrenal gland at the perinatal stage in adult rats was measured here and changes in alpha-mannosidase and N-acetyl-beta-D- glucosaminidase activity were detected. These enzymes increase after birth reaching a peak between days 4 and 7. Other enzymes such as beta-glucuronidase, arylsulfatase and beta-glucosidase did not significantly change at the ages studied. These data suggest that the enzymatic activity and development of the adrenal gland may be correlated during the first week after birth; this is critical since most of the changes occur in this organ.

Assuntos

RESUMO

The epithelium of caput and cauda epididymidis of the rat was studied with transmission electron microscopy (TEM) and freeze-fracture techniques. In thin sections of both zones, the tissue consisted mainly of tall columnar cells (principal cells) with long sterocilia. Clusters of small membrane-bound vesicles were located in the lumen between or immediately over the stereocilia. Freeze-fracture replicas also displayed groups of smooth-surface vesicles in the same location. Membrane-bound vesicles isolated from the lumen of the rat epididymis were studied by TEM. In thin sections, some of them contained an electron dense material and others looked empty. In addition, the hydrolases: beta-galactosidase, N-acetyl-glycosaminidase, alpha-mannosidase, aryl-sulfatase and beta-glucuronidase were detectable in pellets of vesicles treated with Triton X-100. The results presented here indicate the presence of membrane-bound vesicles observed by two different methodologies in the rat epididymal fluid and demonstrate five glycosidases in their content.

Assuntos

RESUMO

1. The Virginia opossum (Didelphis virginiana) possessed an arylsulfatase which had a relative molecular weight of 130 +/- 12 kDa, displayed anomalous kinetics, hydrolysed AA2S, and exhibited other properties of arylsulfatase A. No arylsulfatase B was found. 2. The arylsulfatase present in the gray short-tailed opossum (Monodelphis domestica) had a relative molecular weight of 56 +/- 4 kDa, exhibited linear kinetics, was inhibited by chloride, and possessed other characteristics of arylsulfatase B. No arylsulfatase A was found. 3. Arylsulfatases from both species occurred as multiple isozymes which were unaffected by neuraminidase or alkaline phosphatase treatment.

Assuntos

RESUMO

The cellular localization and activity of the lysosomal enzymes acid phosphatase, trimetaphosphatase, and arylsulfatase were studied in rat bone marrow-derived macrophages infected with Leishmania mexicana amazonensis amastigotes. The specific activity of acid phosphatase normalized for protein content was similar in normal macrophages and in isolated amastigotes, whereas the latter were markedly deficient in trimetaphosphatase and arylsulfatase activities. It is thus likely that trimetaphosphatase and arylsulfatase activities detected in infected macrophages were of host cell origin. The activities of the three enzymes, assayed biochemically, varied independently in the infected macrophages. While arylsulfatase activity was unchanged after infection, the activity of acid phosphatase increased by 19, 40, and 94% at 6, 24, and 48 hr, respectively. Trimetaphosphatase activity rose only slightly during the first 24 hr after infection but increased by 74% at 48 hr. The rise in acid phosphatase activity could be accounted for only partially by multiplication of the amastigotes. Thus, as for trimetaphosphatase, these results suggest enhanced macrophage synthesis of acid phosphatase and/or reduced enzyme degradation by the infected macrophages. The reduction in host cell lysosomes previously described (Ryter et al. 1983; Barbieri et al. 1985) was confirmed but appearance of lysosomal enzyme activity in the parasitophorous vacuole is documented in the present report. Thus, Leishmania do not seem to reduce the amount and the activity of host lysosomal enzymes.

Assuntos

RESUMO

Leishmania mexicana mexicana (M379) amastigotes were found to contain much higher activities than cultured promastigotes of five putative lysosomal enzymes: cysteine proteinase; arylsulfatase (EC 3.1.6.1); beta-glucuronidase (EC 3.2.1.31); DNase (EC 3.1.22.1), and RNase (EC 3.1.27.1). The release profiles of the first three of these enzymes from digitonin-permeabilized amastigotes suggests that they are located within organelles. Cytochemical staining for cysteine proteinase, using gold labeled antibodies and arylsulfatase, showed that both were present in large organelles previously named "megasomes." Comparative studies with L. mexicana amazonensis (LV78), L. donovani donovani (LV9), and L. major (LV39) revealed that L. mexicana amazonensis was similar to L. mexicana mexicana in possessing both high amastigote cysteine proteinase activity and large numbers of megasome organelles in amastigotes, whereas the other two species lacked both these features. The results suggest that the presence of numerous lysosome-like organelles in the amastigote is a characteristic of the L. mexicana group of parasites.

Assuntos

RESUMO

Leishmania amastigotes lodge and multiply within parasitophorous vacuoles, which can fuse with secondary lysosomes of the host macrophages. This study examines the effect of infection with amastigotes of L. mexicana amazonensis on the secondary lysosomes of mouse macrophage cultures. The cultures were stained for the activities of two lysosomal enzyme markers, acid phosphatase and arylsulfatase, and the light microscopic observations were supplemented by electron microscopy. Nearly all noninfected macrophages contained numerous stained secondary lysosomes. The number of such lysosomes was markedly reduced 24 h postinfection, and the reduction persisted for at least 10 days. Stained secondary lysosomes reappeared after the amastigotes were destroyed by exposure of the cultures to phenazine methosulfate or by placing them at 37.5 degrees C. The depletion of lysosomes shown by cytochemical methods may reflect a high rate of fusion of the lysosomes with the parasitophorous vacuoles, exceeding the rate of formation of new secondary lysosomes. Alternatively, the parasites may inhibit the synthesis of lysosomal hydrolases, or the assembly or formation of primary or secondary lysosomes.

Assuntos

RESUMO

Seven acid glycosidases activities have been measured in normal rat uterus during the oestrus cycle. It has been observed that alpha-fucosidase, alpha-mannosidase, beta-galactosidase, alpha-galactosidase, aryl sulfatase, acid phosphatase and hexosaminidase activities changed cyclically during the oestrus cycle. From onward oestrus to metaoestrus the enzyme activities are in their highest level, but then decline slightly towards the resting one, as the cycle progresses. It is possible that changes in glycosidases content bear a lysosomal relationship, since it is known the increase in the lysosome content of the uterus during the oestrus and metaoestrus. The increased enzyme content could be related to uterus glycoproteins secretion and degradation during the normal oestrus cycle.

Assuntos