Arylsulphatase activity of different latosol soils of Ghana cropped to cocoa (Theobroma cacao) and coffee (Coffea canephora var. robusta)

Summary A study was undertaken to investigate arylsulphatase activity in 15 soils cropped to cocoa (Theobroma cacao) and coffee (Coffea canephora var. robusta) in Ghana. The arylsulphatase activity was correlated positively and significantly with organic C, total N, and cation exchange capacity, and correlated negatively with acetate soluble sulphate. The enzyme was deactivated at an incubation temperature of over 60°C. Preheating and oven-drying of soils decreased arylsulphatase activity. Addition of 1.0 ml toluene during the assay resulted in a sharp decline in arylsuphatase activity. The addition of trace elements at a concentration of 1 ppm caused a reduction in soil arylsulphatase activity compared with that of the untreated samples.     

Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.     

Enzymatic activities and microbial communities in an Antarctic dry valley soil: Responses to C and N supplementation

The soils of the Antarctic dry valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain small communities of micro-organisms that contribute to the biogeochemical transformations of the bioelements, albeit at slow rates. We have determined the dehydrogenase, β-glucosidase, acid and alkaline phosphatase and arylsulphatase activities and the rates of respiration (CO₂ production) in laboratory assays of soils collected from a field experiment in an Antarctic dry valley. The objective of the field experiment was to test the responses of the soil microbial community to additions of C and N in simple (glucose and NH₄Cl) and complex forms (glycine and lacustrine detritus from the adjacent lake comprising principally cyanobacterial necromass). The soil samples were taken 3 years after the experimental treatments had been applied. In unamended soil, all enzyme activities and respiration were detected indicating that the enzymatic capacity to mineralize organic C, P and S compounds existed in the soil, despite the very low organic matter content. Relative to the control (unamended soil), respiration was significantly increased by all the experimental additions of C and N except the smallest NH₄Cl addition (1 mg N g⁻¹ soil) and the smallest detritus addition (1.5 mg C g⁻¹ soil and 0.13 mg N g⁻¹ soil). The activities of all enzymes except dehydrogenase were increased by C and combined large C (10 mg C g⁻¹ soil) and N additions, but either unchanged or diminished by addition of either N only or N (up to 10 mg N g⁻¹ soil) with only small C (1 mg C g⁻¹ soil) additions in the form of glucose and NH₄Cl. This suggests that in the presence of a large amount of N, the C supply for enzyme biosynthesis was limited. When normalized with respect to soil respiration, only arylsulphatase per unit of respiration showed a significant increase with C and N additions as glucose and NH₄Cl, consistent with S limitation when C and N limitations have been alleviated. Based on the positive responses of enzyme activity, detritus appeared to provide either conditions or resources which led to a larger biological response than a similar amount of C and more N added in the form of defined compounds (glucose, NH₄Cl or glycine). Assessment of the soil microbial community by ester-linked fatty acid (ELFA) analysis provided no evidence of changes in the community structure as a result of the C and N supplementation treatments. Thus the respiration and enzyme activity responses to supplementation occurred in an apparently structurally stable or unresponsive microbial community.     

Effects of N-enriched sewage sludge on soil enzyme activities

Sewage sludge is increasingly used as an organic amendment to soil, especially to soil containing little organic matter. However, little is known about utility of this organic amendment with N-enriched or adjusted C:N ratios in soil. We studied the effects of adding of different doses (0, 100, 200 and 300 t ha⁻¹) and C:N ratios (3:1, 6:1 and 9:1) of sewage sludge on enzyme activities (β-glucosidase, alkaline phosphatase, arylsulphatase and urease) in a clay loam soil at 25 °C and 60% soil water holding capacity. Nitrogen was added in the form of (NH₄)₂ SO₄ solution to the sludge to reduce the C:N ratio from 9:1 to 6:1 and 3:1. The addition of different doses and C:N ratios of the sludge caused a rapid and significant in the enzymatic activities in soils, this increase was specially noticeable in soil treated with high doses of the sludge. In general, enzymatic activities in sludge-amended soils tended to decrease with the incubation time. All activities reached peak values at 30 days incubation and then gradually decreased up to 90 days of incubation. Sewage sludges also the increased available metal (Cu, Ni, Pb and Zn) contents in the soils. However, the presence of available soil metals due to the addition of the sludge at all doses and C:N ratios did negatively affect all enzymatic activities in the soils. This experiment indicated that all doses and C:N ratios of sewage sludge applied to soil would have harmful effects on enzymatic activity. Some heavy metals found in sewage sludge may negatively influence soil enzyme activities during the decomposition of the sludge.     

Determination of available sulphate in some soils of Ghana using five extraction methods

Summary A study was undertaken to measure the sulphate-S in some representative soils cropped to cocoa (Theobroma cacao) and coffee (Coffea canephora var. robusta) in Ghana using five extraction methods at two soil-extractant ratios. The least extracting power was shown by 0.1 N HCL. A soil-extractant ratio of 1:10 extracted higher amounts of SO ₄ ^2– –S than a 1:5 ratio. There were highly significant differences among the extractants and among the soils. From the 15 soil samples, the highest amount of SO ₄ ^2– –S was extracted at the 1:5 ratio and at the 1:10 ratio by H₂O and the KH₂PO_4– extracting solution, respectively. There was no correlation between arylsulphatase activity and the various amounts of extractable SO_4/2– –S, and therefore soil arylsulphatase activity seems less appropriate as an indicator of plant-available inorganic SO ₄ ^2– –S. In the three soil profiles analysed, the amounts of H₂O-extractable SO ₄ ^2– –S decreased with depth while those extracted by sodium acetate buffer increased with depth. The possibility of large amounts of extractable SO ₄ ^2– –S in the subsoils should be considered along with the SO ₄ ^2– –S in the surface samples if an estimation is made of the available –S status of cocoa and coffee rooting zones.     

Determination of arylsulphatase and phosphatase enzyme activities in soil using screen-printed electrodes modified with multi-walled carbon nanotubes

Sustainability of agricultural systems has become an important issue all over the world. The activity of enzymes is potentially an important quality bioindicator in soils. The aim of the present study was to develop a simple and convenient assay to determine the activity of arylsulphatase (AS), acid (ACP) and alkaline phosphatase (ALP) in agricultural soil. The activities of these enzymes were detected using a non-electroactive substrate, which produces an electroactive product. To this end, p-aminophenyl phosphate (pAPP) was used as a substrate which is converted to p-aminophenol (pAP) after enzymatic dephosphorylation; and 4-nitrocatechol sulphate (4-NCS) was used as a substrate for AS activity based on its catalytic effect on the hydrolysis of 4-NCS into 4-nitrocatechol (4-NC). The products of both enzymatic reactions were quantified on carbon-based screen-printed electrodes (SPCEs) modified with carbon nanotubes (CNTs), using Osteryoung square-wave voltammetry (OSWV). The determination of the reaction products allowed more sensitive determination of ALP, ACP and AS activities in soil than that obtained with a spectrophotometric method. This assay also diminishes the generation of waste, which is desirable in green analytical chemistry. The optimization of the analytical procedure in terms of the nature of electrode type, applied potential, pH of solution, and precision of measurements is reported.     

Effect of the addition of municipal solid-waste compost on microbial biomass and enzyme activities in soil

Summary Changes in the content of C, N, P, and S in the soil biomass and in phosphatase, urease, protease, deaminase, and arylsulphatase activity, induced by amendment with municipal solid-waste compost, were determined in a clay loam soil during 1 year of incubation at 25° and 35°C.In the unenriched soil (control) decreasing trends in biomass C, biomass N, and biomass S were observed at both temperatures. In the enriched soil, these values increased, reaching a maximum after 1 month. Biomass P, probably due to a slower process of P immobilization, showed different trends. Alkaline phosphomonoesterase, phosphodiesterase, and deaminase activity remained constant after reaching maximum values (3–5 months). Arylsulphatase, urease, and protease activity tended to return to baseline after reaching a maximum (2–3 months).Atrazine, though applied at a dose that was 10 times higher than the recommended field rate, did not modify the chemical and biochemical properties of either the control or the enriched soil.Significant positive and negative correlations between changes in biomass values and changes in enzyme activity were found. The negative correlations are attributed to the delay in the enzymatic response compared with the changes in microbial biomass.     

Effects of ridging on crop performance and symbiotic N2 fixation of fababean (Vicia faba L.)

Abstract. The success of organic cropping systems depends on symbiotic N₂ fixation by leguminous crops, and it is important to explore new management systems to improve the nitrogen input through N₂ fixation. During two growing seasons the possible advantage of growing fababean ( Vicia faba L.) in ridges was studied in comparison to the traditional method on flat soil. Differences in soil physical parameters resulted in a significantly greater microbial activity and a deeper root system at the flowering stage when grown in the ridge than on the flat. Consequently, the amount of fixed N at flowering was significantly greater in ridges than in flat soil. However, during the period from flowering until harvest, when the major part of the N uptake and N₂ fixation took place, the differences between the treatments disappeared. Average values for the growing season of fluorescein diacetate hydrolysis, arylamidase activity and arylsulphatase activity were significantly greater in the ridge than on the flat, and the microbial biomass-C, derived from substrate induced respiration (SIR), was on average 232 and 223 μg C g⁻¹ soil in the ridge and on the flat, respectively. Measured total-N uptake, including root N (0–30 cm depth), ranged from 206 to 247 kg N ha⁻¹, of which 182–201 kg N ha⁻¹ was fixed N. From 154 to 173 kg N ha⁻¹ was removed in grain resulting in a soil-N balance of +28 kg N ha⁻¹ in both years. However, by including estimates of total root N and rhizodeposition-N the soil-N balance ranged from +52 to +62 kg N ha⁻¹.     

Fluoride-induced changes in chemical properties and microbial activity of mull,moder and mor soils

Summary Fluoride-induced changes of chemical properties and microbial activities in humus soils were investigated in 12-week lysimeter experiments. The mull soil showed the highest F-adsorption capacity, in which 94% of the fluoride added was retained after addition of 4.5 mg F/cm² as NaF. The moder and mor soils only adsorbed 52% and 41%, respectively. F-additions induced leaching of organic matter, Fe, Al and P and increases in soil pH in the moder and mor. In contrast no Al, Fe and P was leached from the mull and only minor amounts of organic matter dissolved after a single application of 4.5 mg F/cm². Treatments with NaF up to 3700 mg F/kg did not significantly reduce respiration in any of the humus forms. Dehydrogenase, alkaline phosphatase and arylsulfatase activities as well as nitrification were inhibited at much lower F-additions in the moder and mor soils. A significant decrease in ammonification was observed in the moder. In contrast, microbial processes in the mull soil were not inhibited. This is due to its high adsorption capacity and the relatively low toxicity of F-ions. According to computations using GEOCHEM, the F-ion was the most abundant species in mull lysimeter leachates. Leachates of moder and mor soils contained mainly AIF-complexes (90%–99%). The lack of any effects from NaF treatment on soil respiration is attributed to the observed positive effects, e.g. dissolution of organic matter, desorption of P and increases in soil pH.     

An ecological dose-response model approach to short- and long-term effects of heavy metals on arylsulphatase activity in soil

Summary The aim of this study was to provide data to evaluate the short- and long-term effects of heavy metals on arylsulphatase activity in five soils. The effects are fitted on a logistic dose-response model and are presented graphically as the ecological dose (heavy metal concentration corresponding to 50% inhibition; ED₅₀) and ecological dose range (heavy metal concentration range corresponding to 10–90% inhibition; EDR). In 7 out of 22 comparable soil-metal combinations the ED₅₀ decreased significantly over 6 weeks to 18 months of incubation and in two cases the ED₅₀ increased. Toxicity (defined as ED₅₀) was highest in sand and sandy loam and lowest in sandy peat. Cd toxicity in sand, silty loam, and clay varied from 1.08 to 9.04 mmol kg^-1. Both Cr and Ni toxicity varied strongly and decreased with time in some soils while increasing in others. The Cu toxicity ranged from 4.51 to 2 mmol kg^-1 in sand and silty loam, respectively, but remained fairly constant over time. Pb was the least toxic element (14.5 to 59.9 mmol kg^-1). The toxicity of Zn ranged from 5.73 to 148 mmol kg^-1 in sand and sandy peat, respectively. At critical concentrations set by the Dutch Soil Protection Act, Cr, Cu, Ni, and Zn inhibited arylsulphatase by 53, 35, 48 and 97%, respectively.