Riboflavin content in autofluorescent earthworm coelomocytes is species-specific

We have recently shown that a large proproportion of earthworm coelomocytes exhibit strong autofluorescence in some species (Dendrobaena veneta, Allolobophora chlorotica, Dendrodrilus rubidus, Eisenia fetida, and Octolasion spp.), while autofluorescent coelomocytes are very scarce in representatives of Lumbricus spp. and Aporrectodea spp. Riboflavin (vitamin B2) was identified as a major fluorophore in Eisenia jetida coelomocytes. The main aim of the present experiments was to quantify riboflavin content in autofluorescent coelomocytes (eleocytes) from several earthworm species through a combination of flow cytometric and spectrofluorometric measurements. Spectrofluorometry of coelomocyte lysates showed that riboflavin was non-detectable in the coelomocytes of Aporrectodea spp. and Lumbricus spp., but was a prominent constituent of lysates from species with autofluorescent eleocytes. In the latter case, riboflavin content was the highest in E. fetida, followed by Octolasion spp. > A. chlorotica > D. rubidus. The riboflavin content of coelomocytes correlates positively with eleocyte autofluorescence intensity measured by flow cytometry and visible with fluorescence microscopy.     

Distribution, abundance and species associations of earthworms (Lumbricidae) in a reclaimed peat soil in Ireland

Fifteen species of earthworm were collected from a reclaimed fen peat soil used for rough hay in County Offaly, Ireland. The most common species were Aporrectodea tuberculata, Allolobophora chlorotica, Eisenia rosea and Octolasion tyrtaeum. A. tuberculata, A. chlorotica and E. rosea formed a significant association. The total numbers of earthworms collected by hand-sorting reached a maximum of 197.1 m⁻². Compared with hand-sorting, formalin-expulsion was an inefficient sampling method for most species. Soil moisture varied within the study area. Total densities and biomasses of the earthworms were greater where the soil was drier. A. tuberculata, A. turgida, Satchellius mammale and the pink form of A. chlorotica were more common in the dry soils whilst O. tyrtaeum, Lumbricus rubellus and the green form of A. chlorotica were more common in the wet soils.     

Glutathione S-transferases in earthworms (Lumbricidae).

Glutathione S-transferase activity (EC 2.5.1.18) was demonstrated in six species of earthworms of the family Lumbricidae: Eisenia foetida, Lumbricus terrestris, Lumbricus rebellus, Allolobophora longa, Allolobophora caliginosa and Allolobophora chlorotica. Considerable activity was obtained with 1-chlorl-2,4-dinitrobenzene and low activity with 3,4-dichloro-1-nitrobenzene, but no enzymic reaction was detectable with sulphobromophthalein 1,2-epoxy-3-(p-nitrophenoxy)propane of trans-4-phenylbut-3-en-2-one as substrates. Enzyme prepartations from L. rubellus and A. longa were the most active, whereas A. chlorotica gave the lowest activity. The ratio of the activities obtained with 1-chloro-2,4-dinitrobenzene and 3,4-cichloro-1-nitrobenzene was very different in the various species, but no phylogenetic pattern was evident. Isoelectric focusing gave rise to various activity peaks as measured with 1-chloro-2,4-dinitrobenzene as a substrate, and the activity profiles of the species examined appeared to follow a taxonomic pattern. The activity of Allolobophora had the highest peak in the alkaline region, whereas that of Lumbricus had the highest peak in the acid region. Eisenia showed a very complex activity profile, with the highest peak ne pH 7. As determined by an enzymic assay, all the species contained glutathione, on an average about 0.5 mumol/g wet wt. Conjugation with glutathione catalysed by glutathione S-transferases may consequently be an important detoxification mechanism in earthworms.     

Opening a can of worms: unprecedented sympatric cryptic diversity within British lumbricid earthworms

Earthworms play a major role in many aspects of soil fertility, food web ecology and ecosystem functioning, and hence are frequently the subjects of, for example, ecological and toxicological research. Our aim was to examine the genetic structure of common earthworm species, to identify cryptic lineages or species that may be distinct ecotypes or biotypes (and hence confound current research based upon morphotypes) and to try to explain the massive cryptic diversity that eventually emerged. We demonstrated that species such as Allolobophora chlorotica, Aporrectodea longa, Aporrectodea rosea and Lumbricus rubellus all comprise highly divergent lineages with species-level divergence at the mitochondrial cytochrome oxidase I (COI) gene. In Allo. chlorotica alone, we found 55 haplotypes for COI, with 35 of these being found in pink and 20 in green morph worms. There were no cases of the two colour morphs sharing COI haplotypes. Phylogenetic analyses of mitochondrial COI and 16S genes showed the presence of five highly divergent lineages, suggesting the presence of multiple cryptic species within Allo. chlorotica. There was no clear geographical pattern to lineage distribution and many populations were polymorphic for both mitochondrial DNA lineage and colour morph. Amplified fragment length polymorphism results, based on two primer combinations, were broadly congruent with mitochondrial DNA results with one significant exception. Despite showing over 14% divergence at COI, amplified fragment length polymorphism markers showed that the two green morph lineages may be interbreeding and therefore represent a single taxon. The cryptic diversity revealed by these results has profound consequences for all areas of earthworm research.     

Autofluorescence in eleocytes of some earthworm species

Immunocompetent cells of earthworms, coelomocytes, comprise adherent amoebocytes and granular eleocytes (chloragocytes). Both cell populations can be expelled via dorsal pores of adult earthworms by exposure to an electric current (4.5 V) for 1 min. Analysis by phase contrast/fluorescence microscopy and flow cytometry demonstrated that eleocyte population of several species exhibits a strong autofluorescence. A high percentage (11-35%) of autofluorescent eleocytes was recorded in Allolobophora chlorotica, Dendrodrilus rubidus, Eisenia fetida, and Octolasion sp. (O. cyaneum, O. tyrtaeum tyrtaeum and O. tyrtaeum lacteum). In contrast, autofluorescent coelomocytes were exceptionally scarce (less than 1%) in representative Aporrectodea sp. (A. caliginosa and A. longa) and Lumbricus sp. (L. castaneus, L. festivus, L. rubellus, L. terrestris). Thus, this paper for the first time describes profound intrinsic fluorescence of eleocytes in some--but not all--earthworm species. The function (if any) and inter-species differences of the autofluorescent coelomocytes still remain elusive.     

A comparison of the effects of sward improvement on invertebrates, sward establishment and herbage yield

Field experiments were done at two widely separated sites in England (Tadcaster, North Yorkshire and North Wyke, Devon). In each case an old permanent sward was re-seeded after ploughing or by direct drilling, or was left intact and fertilised. The carbamate pesticide aldicarb was applied to half of each experimental plot. The effects of sward improvement and pesticide on various soil invertebrate groups were assessed. Soil-dwelling macrofauna arthropods were scarce at both sites. Stem-boring dipterous larvae, however, were numerous at both sites. At Tadcaster, Oscinella vastator was the only species present in the original sward, but 0. frit was by far the most prevalent species in re-seeded areas. These can only have arisen from direct oviposition of eggs by adults on or near the emerging seedlings and not by migration of larvae from buried turf or the desiccated old pasture.
Mites and Collembola were abundant. Their numbers were reduced initially by cultivation and pesticide usage, but the effects of these practices were transient and their numbers recovered to previous levels usually within 10 wk.
Earthworms were present at both sites. Deep burrowing species, e.g. Lumbricus terrestris and Allolobophora longa were less affected by the treatments imposed than species such as A. chlorotica and L. rubelius which usually live close to the soil surface. Effects on their numbers were in any case, short-lived.
No improvement method consistently provided the greatest herbage dry matter yield. Pesticide application, however, greatly increased seedling stand and/or herbage yield at both sites and showed the benefits of using crop protectants, especially on direct-drilled re-seeds.     

STUDIES ON THE RELATIONSHIPS BETWEEN EARTHWORMS AND SOIL FERTILITY: I. BIOLOGICAL STUDIES IN THE FIELD

Changes in the seasonal activity of several species of earthworms have been followed in a permanent pasture field for 18 months, 1945–6. The two soil conditions which chiefly determine activity are temperature and moisture. Other factors are the occurrence of an obligatory diapause in the two species Allolobophora nocturna and A. longa , and changes in population in A. chlorotica and Lumbricus terrestris.
Soil temperature and soil moisture also determined the weight of soil thrown up in the form of wormcasts during autumn, winter and spring. It is suggested that only two species, A. nocturna and A. longa , are responsible for wormcasts and that the other four common species present play little or no part in this activity.
At Rothamsted it was found that the previous agricultural history of the field is an important factor in determining the fauna. Old permanent pasture is characterized by a high percentage of A. nocturna and a rather lower percentage of A. caliginosa. Ploughing old permanent pasture and reseeding to grass after 1 or 2 years arable reduces the proportions of A. nocturna and A. caliginosa and increases that of Eisenia rosea. Arable fields have A. chlorotica as the dominant species and pasture fields 2–7 years grass after many years of arable fanning still show a high percentage of A. chlorotica and a low proportion of A. nocturna.
A survey of the Carse of Stirling, Scotland, showed that soil type is also an important factor in determining the earthworm fauna. A. caliginosa was the dominant species on the three soil types studied, but the subdominant species varied. On clay soil, A. longa was subdominant; on loam, A. longa and L. rubellus ; on sandy soil, A. longa, L. rubellus and A. chlorotica. The dominant species of pasture land at Rothamsted, A. nocturna , was not found at Stirling.     

Earthworm populations in conventional and integrated farming systems in the LIFE Project (SW England) in 1990–2000

Dilute formalin was used to sample earthworm populations in a field experiment comparing conventional (CFS) and integrated (IFS) farming systems, at Long Ashton in SW England during 1990–2000. Crops in the CFS were established by ploughing. Those in the IFS treatments were established by non‐inversion tillage: in the first 5 yrs using a Dutzi cultivator or by direct drilling (IFS‐1); from 1994 onwards using either a Vaderstad cultivator (IFS‐2) or a Dutzi cultivator (IFS‐3). These treatments had little or no effect on earthworm populations over the first 3 yrs of the experiment, but after this time total earthworm numbers and biomass were generally greater in the IFS treatments than in the CFS. Individual earthworm species (determined from 1995 onwards) differed in their response to the different farming systems. Numbers of Allolobophora chlorotica, Lumbricus festivus, L. rubellus and L. terrestris averaged over all years were significantly greater in IFS‐3 than in CFS, with densities in IFS‐2 nearly always intermediate and not significantly different from either extreme. Average treatment differences for other species were not significant, although in most years numbers of Aporrectodea longa, Lumbricus castaneus and Octolasion spp. were greatest in IFS‐3, with IFS‐2 similar to or less than CFS. There were no consistent differences between treatments for Aporrectodea caliginosa and A. rosea. Tillage method and the number of crop establishment passes were probably the main factors affecting earthworm populations, although the abundance and distribution of some species may also have been influenced by the amount of soil organic matter. During the period 1995–2000,13 species of earthworms were recorded from the site with A. caliginosa and Al. chlorotica the dominant species. These and other species which normally live in temporary burrows close to the soil surface formed about 80% of the total earthworms extracted, with the larger deep burrowing species, such as A. longa and L. terrestris, representing <20% of the total catch. Species diversity was consistently greater in the Dutzi‐based integrated system (IFS‐3) than in either the Vaderstad‐based integrated system (IFS‐2) or the conventional system (CFS). It is suggested that knowledge of the species composition of earthworm communities is essential in order to properly anticipate the likely impact of modified farming practices on earthworm populations. Careful consideration of the specific machine(s) used for tillage operations may also be required.     

Biogeographical zonation of the western Iberian peninsula on the basis of the distribution of earthworm species

We used TWINSPAN and CANOCO to investigate the biogeography of the western Iberian Peninsula on the basis of the distribution of earthworms among ninety areas of Galicia, Portugal, Asturias, León, Zamora, Salamanca, Cáceres, Badajoz and Huelva. This part of Iberia is clearly divisible into a Eurosiberian Region in the north and west and a Mediterranean Region in the south and east. For earthworm faunas, however, the limit between these regions is considerably further south than is conventionally accepted on the basis of Rivas Martinez's (1987) vegetation-type classification. Species character- istic of the Eurosiberian Region include Dendrobaena madeirensis, D. octaedra, Allolobophora caliginosa and various species of the genus Lumbricus . Within this region the earthworm fauna of Asturias is clearly distinct from that of Galicia and northern Portugal. Species characteristic of the Mediterranean Region include Allolobophora caliginosa , A. chlorotica and A. rosea , but inventories from this region are most easily identified by the absence or scarcity of those species characteristic of the Eurosiberian Region. Many areas show intermediate characteristics between the two major regions, and in some cases one region 'intrudes' into the other.     

Endodermal secretion of chitin in the 'cuticle' of the earthworm gizzard

The gizzard of earthworms is definitely of endodermal origin. Contrary to the opinion that tissue of endodermal origin is unable to synthesize chitin, the gizzard epithelium secretes large amounts of chitin-containing material which has special properties. 28.7 +/- 5.7% of the dry weight proved to be chitin; the microfibres form a random felt-like texture. They are not arranged in layers comparable to those found in arthropod cuticle. The protein content amounts to 44.9 +/- 7.1% of the dry weight; the remaining material contains at least uronic acids. In the protein matrix large amounts of the enzymes amylase and protease have been demonstrated. As the so-called cuticle is sloughed off at the lumen side, these enzymes are mingled with the gut contents. It might be called a gastric shield, as it closely resembles this structure, widespread among Mollusca. The thickness of the gizzard cuticle varies between 10 and 90 mum in Lumbricus terrestris and 10-50 mum in L. rubellus. Autoradiography has shown that it is replaced at a high rate. In Lumbricus terrestris it is renewed completely in less than 60 hr, and in smaller Lumbricus rubellus, this takes place in about 48 hr. These results are in agreement with the biochemical findings.     

Gizzard myoglobin contents and feeding habits in avian species

In an attempt to consider physiological function of myoglobin (Mb), we determined Mb contents of gizzard smooth muscles with special reference to feeding habits in 85 avian species of 19 orders. The Mb content in 44 species of herbivorous birds was 7.52+/-3.81 mg/g wet muscle, which was significantly higher than the value of 2.34+/-1.74 mg/g in 41 species of carnivorous ones (P<0.001). Buffering capacity, as determined by in vitro titration method, was 37.3+/-5.5 slykes/g in gizzard smooth muscles of 75 species and 60.7+/-10.5 slykes in breast skeletal muscles of 77 species (P<0.001), which suggests a significantly higher dependence, almost comparable to cardiac muscles, of the gizzard muscular function on aerobic metabolism. Together with the fact that blood circulation in the gizzard is very low at resting, and might be further limited during activity, we conclude that the higher Mb content in gizzards of herbivorous birds is an adaptation, to allow storage and/or facilitated diffusion of oxygen, during process of high mechanical work required to grind down hard and fibrous vegetable food under the conditions of limited circulatory supply.     

Characterization of cholinesterases in plasma of three Portuguese native bird species: application to biomonitoring

Over the last decades the inhibition of plasma cholinesterase (ChE) activity has been widely used as a biomarker to diagnose organophosphate and carbamate exposure. Plasma ChE activity is a useful and non-invasive method to monitor bird exposure to anticholinesterase compounds; nonetheless several studies had shown that the ChE form(s) present in avian plasma may vary greatly among species. In order to support further biomonitoring studies and provide reference data for wildlife risk-assessment, plasma cholinesterase of the northern gannet (Morus bassanus), the white stork (Ciconia ciconia) and the grey heron (Ardea cinerea) were characterized using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine sulphate, BW284C51, and iso-OMPA). Additionally, the range of ChE activity that may be considered as basal levels for non-exposed individuals was determined. The results suggest that in the plasma of the three species studied the main cholinesterase form present is butyrylcholinesterase (BChE). Plasma BChE activity in non-exposed individuals was 0.48±0.11 SD U/ml, 0.39±0.12 SD U/ml, 0.15±0.04 SD U/ml in the northern gannet, white stork and grey heron, respectively. These results are crucial for the further use of plasma BChE activity in these bird species as a contamination bioindicator of anti-cholinesterase agents in both wetland and marine environments. Our findings also underscore the importance of plasma ChE characterization before its use as a biomarker in biomonitoring studies with birds.     

Distribution, prevalence and intensity of earthworm populations in arable land and grassland in Scotland

The earthworms of arable and pasture fields from 100 randomly chosen arable farms were identified and counted and their relationship with soil factors examined. Thirteen species of earthworm were recorded including Lumbricus friendi from Scotland for the first time. The most prevalent and numerous species were Aporrectodea longa, Aporrectodea caliginosa and Lumbricus terrestris. All earthworm species had cosmopolitan distributions apart from Aporrectodea nocturna and Lumbricus festivus which were confined to southern/central Scotland. Four soil characteristics (% moisture, % sand, % organic matter and pH) shared no relationship with species recorded but tillage may have had a detrimental effect on species composition and size of population. It is suggested that the magnitudes of the earthworm populations found, particularly in permanent pasture, were important in maintaining soil structure and fertility, and the spread of the New Zealand flatworm (Artioposthia triangulata), an obligate predator of earthworms, could have a considerable impact on agricultural productivity and wildlife in Scotland.     

Coordinated peripheral neuronal activities among the different regions of the digestive tract in Aplysia

Peripheral neuronal somata are scattered throughout the enteric nervous system (ENS) in Aplysia. We found that somata on the outer surface of the digestive tract were more densely distributed on the stomatogastric ring and the posterior gizzard than on other regions. In preparations with or without the central nervous system, two types of synchronous bursting activity were recorded from the nerves of the ENS. Some of the synchronous bursts were recorded from nerves on the crop and stomatogastric ring, whereas others were recorded from nerves on the crop, stomatogastric ring, and gizzard. Experiments using preparations in which the different regions were separated suggested that the former bursts originated in neurons on the crop and the latter originated in neurons on the gizzard. Axonal projections of neurons on the different regions were examined by backfilling and analysis of the direction of impulse conduction. Blocking chemical synapses in separated gizzards depressed EPSP-like potentials and eliminated the bursting activities. When chemical synapses on the crop and stomatogastric ring but not on the gizzard were blocked in a whole digestive tract preparation, bursting activity recorded from nerves on all the regions was decreased, although the frequency of the bursting rhythm did not change. Stimulation of a neuron on the crop elicited bursts in nerves on the gizzard. These results suggest that chemical synaptic connections and a feedback loop along the digestive tract coordinate the synchrony of bursting activity originating in the gizzard.     

In vitro characterization of cholinesterases in the earthworm Eisenia andrei

Assessment of pollution impact in soil ecosystems has become a priority and interest has grown concerning the use of invertebrates as sentinel organisms. Inhibition of cholinesterase (ChE) activity has a great potential as a biomarker of pesticide exposure, and we evaluated the ChE kinetic parameters in the earthworm Eisenia andrei in the presence of acetylthiocholine (ASCh), proprionylthiocholine (PSCh) and butyrylthiocholine (BSCh). The highest ChE activity was found in the presence of ASCh and PSCh (42.45 and 49.82 nmol min(-1) mg protein(-1), respectively). BSCh was hydrolyzed at a rate of 4.04 nmol min(-1) mg protein(-1), but the time course did not reach a plateau under our experimental conditions. Km values were 0.142+/-0.006 and 0.183+/-0.053 mM for ASCh and PSCh, respectively. ASCh and PSCh hydrolysis were significantly inhibited by eserine (IC50 values were 1.44 x 10(-8) and 1.20 x 10(-8) M, respectively) and by carbaryl (IC50 values of 5.75 x 10(-9) and 4.79 x 10(-9) M). The presence of different ChEs in tissues from E. andrei was assessed by using selective inhibitors for AChE (BW284c51) and BChE (iso-OMPA). BW284c51 strongly reduced ASCh and PSCh hydrolysis and slightly affected that of BSCh, while iso-OMPA was without effect in all cases.     

Seasonal variation in the abundance, biomass and biodiversity of earthworms in soils contaminated with metal emissions from a primary smelting works

1. Earthworms (Annelida: Oligochaeta) were sampled on four occasions (spring, summer, autumn and winter) at 14 sites along two transects from a primary lead/ zinc/cadmium smelting works at Avonmouth, UK.
2. Total abundance and biomass of earthworms decreased with proximity to the smelter. No worms were collected from the two sites closest to the factory (<0·6 km) and catches were significantly lower than controls at a further five sites (<3 km).
3. Seasonal composition of sampled communities differed only for summer with lower numbers of individuals and species collected at all sites. Reduced catches in the summer sample is a response to drought.
4. Species richness was lowest at sites close to the factory. For example, worms such as Aporrectodea caliginosa (Savigny) and Allolobophora chlorotica (Savigny) that were dominant at relatively clean sites further from the smelter are absent from the most contaminated soils.
5. Reduced species richness resulted in lower Shannon–Weiner diversity and higher Berger–Parker dominance. Multivariate cluster analysis for spring, summer and winter indicated that sites could be split into three groups based upon relative species composition. In autumn, two clusters were identified.
6. The absence of sensitive species from sites close to the smelting works supports the inclusion of earthworms as a key group in a terrestrial prediction and classification scheme for quantifying the effects of pollutants on soil biodiversity. However, sampling should be carried out in spring or autumn to obtain an accurate picture of community structure.     

The possible roles of the monoaminergic system in the feeding of the snail Helix pomatia

The possible role of serotonin and dopamine in the feeding of Helix pomatia was studied applying immunocytochemical, biochemical, and behavioral techniques as well as bioassay experiments. Immunocytochemistry showed that dopamine-containing (thyrosin-hydroxylase-immunoreactive) neuronal elements of the crop and the gizzard belong to the intrinsic part, whereas serotonin-containing (serotonin-immunoreactive) neuronal elements belong to the extrinsic part of the gastrointestinal nervous system. Bioassay studies on the spontaneous contractions of the crop and the gizzard showed that dopamine affected only the longitudinal muscle contractions by increasing both the tonus and contractility, whereas serotonin was effective on both the longitudinal and circular muscle contractions. Serotonin increased the tonus and contractility of longitudinal muscles in the crop but decreased them in the gizzard. Serotonin decreased the tonus and contractility of the circular muscles in the crop but increased them in the gizzard. Serotonin effects on the circular muscle of the gizzard were concentration dependent between a range of 10(-5) M-3 x 10(-5) M. HPLC measurements of monoamines in starved and satiated animals showed that the concentration of both dopamine and serotonin significantly decreased in both the CNS and different parts of the gastrointestinal tract of satiated animals, suggesting a significant monoamine liberation during feeding. The injection of monoamines (10(-3) and 10(-2) M) into the body cavity of starved animals showed that only dopamine was able to induce feeding whereas serotonin increased the general activity of the animals suggesting that the initiation of feeding is rather dopamine than serotonin dependent.     

Characterization of plasma cholinesterase activity in the Eurasian Griffon Vulture Gyps fulvus and its in vitro inhibition by carbamate pesticides

The legal and illegal use of organophosphorus and carbamate pesticides represents one of many threats to birds. The activity of the cholinesterase enzyme in plasma is used as a non‐destructive biomarker to diagnose the exposure of birds to these pesticides. Scavengers are one of the most important bird groups threatened by the use of baits poisoned with anticholinesterase pesticides. Knowledge of the characteristics of this enzyme in each bird species is crucial, as several studies indicate that more than one cholinesterase form may be present in the plasma of birds. In this study, cholinesterase activity was characterized in the plasma of the Eurasian Griffon Vulture Gyps fulvus by using several substrates and inhibitors of the enzyme, and its normal activity value was also determined. The in vitro sensitivity of Gyps fulvus plasma cholinesterase to carbamate insecticides (aldicarb, carbaryl and methomyl) was also investigated. The results indicated that propionylthiocholine iodide was the preferred substrate to determine plasma cholinesterase activity, followed by acetylcholine iodide and S‐butyrylcholine iodide, and acetylcholinesterase was the predominant enzymatic activity in Gyps fulvus plasma. Aldicarb was the most potent in vitro inhibitor of plasma cholinesterase activity in this species. However, cholinesterase enzymatic activity was significantly inhibited by all tested carbamates, providing further evidence that this biomarker is a suitable tool to monitor the exposure to these poisons in the field, highlighting its utility in conservation programmes.     

Gill (Na+,K+)-ATPase in diadromous, freshwater palaemonid shrimps: species-specific kinetic characteristics and alpha-subunit expression

To better comprehend physiological adaptation to dilute media and the molecular mechanisms underlying ammonia excretion in palaemonid shrimps, we characterized the (Na+,K+)-ATPase from Macrobrachium amazonicum gills, disclosing high- (K(0.5) = 4.2+/-0.2 micromol L(-1); V = 33.9+/-1.9 U mg(-1)) and low-affinity (K(0.5) = 0.144+/-0.010 mmol L(-1); V = 232.9+/-15.3 U mg(-1)) ATP hydrolyzing sites. Stimulation by Na+ (K(0.5) = 5.5+/-0.3 mmol L(-1); V = 275.1+/-15.1 U mg(-1)), Mg2+ (K(0.5) = 0.79+/-0.06 mmol L(-1); V = 261.9+/-18.3 U mg(-1)), K+ (K(M) = 0.88+/-0.04 mmol L(-1); V = 271.8+/-10.9 U mg(-1)) and NH4(+) (K(M) = 5.0+/-0.2 mmol L(-1); V = 385.9+/-15.8 U mg(-1)) obeys single saturation curves, activity being stimulated synergistically by NH4(+) and K+. There is a single K+ binding site, NH4(+) binding to a second, exclusive site, stimulating activity by 33%, modulating K+ affinity. (Na+,K+)-ATPase activity constitutes approximately 80% of total ATPase activity (K(Iouabain) = 147.5+/-8.9 micromol L(-1)); Na+-, K+-, Ca2+-, V- and F(o)F(1)-ATPases are also present. M. amazonicum microsomal fractions possess approximately 2-fold less (Na+,K+)-ATPase alpha-subunit than M. olfersi, consistent with a 2.6-fold lower specific activity. These differences in (Na+, K+)-ATPase stimulation by ATP and ions, and specific activities of other ATPases, suggest the presence of distinct biochemical adaptations to life in fresh water in these related species.     

Arginase and ornithine, as markers in human non-small cell lung carcinoma

The arginase activity and ornithine level were determined in tissue obtained from patients with non-small cell lung carcinoma (NSLC). The arginase activity and ornithine level in tumor tissues were 1.89 +/- 1.28 U/mg protein and 42.32 +/- 25.82 nmol/mg protein, respectively versus 0.67 +/- 0.19 U/mg protein and 10.12 +/- 3.69 nmol/mg protein for normal tissues (p < 0.01).