Macroinvertebrate community response to natural and forest harvest gradients in western Oregon headwater streams

1. To examine the effects of forest harvest practices on headwater stream macroinvertebrates, we compiled a 167 site database with macroinvertebrate, fish, physical habitat and catchment land cover data from the three forested ecoregions in western Oregon. For our analysis, headwater streams were defined by catchment areas <10 km² and perennial water during summer low flows. Almost all sites in the database were selected using a randomised survey design, constituting a representative sample of headwater streams in these ecoregions. 2. Macroinvertebrate taxonomic and functional feeding group composition were very similar among the three ecoregions in the study area (Coast Range, Cascades and Klamath Mountains). On average, 55% of the individuals at each site were in the orders Ephemeroptera, Plecoptera or Trichoptera. Dipteran taxa (mostly chironomids) accounted for another 34%. At almost all sites, non‐insects made up <10% of the macroinvertebrate assemblage. Almost half (49%) of the assemblages were collectors; remaining individuals were about evenly divided among scrapers, shredders and predators. 3. There were 189 different macroinvertebrate taxa at the 167 sites with richness at individual sites ranging from 7 to 71 taxa. Ordination by non‐metric multidimensional scaling revealed a strong association between % Ephemeroptera, especially Baetis, and site scores along the first axis. This axis was also strongly related to % coarse substratum and fast water habitat. The second axis was strongly related to % intolerant individuals, site slope and altitude. No strong relationships were evident between any ordination axis and either logging activity, presence/absence of fish, catchment size or ecoregion. 4. Based on macroinvertebrate index of biotic integrity (IBI) scores, 62% of the sites had no impairment, 31% of the sites had slight impairment and only 6% of the sites had moderate or severe impairment. IBI scores were not strongly related to forest harvest history. All four severely impaired sites and five of the seven sites with moderate impairment were lower altitude, shallower slope stream reaches located in the Coast Range with evidence of agricultural activity in their catchment or riparian zone. % sand + fine substratum was the environmental variable most strongly related to macroinvertebrate IBI.     

Biomass and chemical composition of common forest plants in response to fire in western Norway

Abstract. The biomass and chemical composition in six dominant field and bottom layer species was followed during four years after a fire in a Pinus sylvestris forest in western Norway. Three fire intensity levels were distinguished: low, medium and high. The overall biomass in the different species was estimated from the biomass per shoot, the shoot densities in pure stands of the investigated species and the percentage cover at medium burned sites. Corresponding measurements were made at control plots outside the burned area. A strong post-fire increase in the overall biomass of Calluna vulgaris, Polytrichum spp., Deschampsia flexuosa and Pteridium aquilinum was found, against a much slower regrowth of Vaccinium myrtillus and V. vitis-idaea. The Vaccinium species and Calluna were the dominant species at the control plot. Accumulation of carbohydrates seemed to take place in green and non-green tissue of Pteridium and Deschampsia. A corresponding accumulation of nitrogen was found in green and non-green Calluna and in non-green Vaccinium myrtillus tissue, and of phosphorus in green and non-green tissue of both Vaccinium species and Calluna as a result of fire. The regrowth of Calluna was mainly from seeds that appeared to be present in the soil before the fire. The regeneration of Pteridium and the two Vaccinium species took place almost exclusively vegetatively from below-ground rhizomes that had survived the fire. Three years after the fire the overall biomass at the burned site was higher than at the control site, due to improved light and nutrient conditions. However, the biomass is expected to decrease in the future and the species composition will probably change as nutrients are leached out of the soil and Pinus and deciduous trees (Betula pubescens and Salix caprea) regenerate from seeds and roots, leading to increased competition in the field and shrub layer.     

Changes in soil pH across England and Wales in response to decreased acid deposition

Analysis of data from the National Soil Inventory of England and Wales obtained between 1978 and 2003 shows widespread increases in soil pH – i.e., soils became less acid – across both countries during the survey period. In general, soil pH increased under all land uses. At least part of the increase and its regional variation could be explained by decreased sulphur deposition from the atmosphere. Changes in liming practices on arable land probably also contributed. The effect of decreased sulphur deposition was moderated by land use, soil properties – particularly soil pH and organic carbon content – and the level of past sulphur deposition.     

Malonyl CoA control of fatty acid oxidation in the newborn heart in response to increased fatty acid supply

The concentration of fatty acids in the blood or perfusate is a major determinant of the extent of myocardial fatty acid oxidation. Increasing fatty acid supply in adult rat increases myocardial fatty acid oxidation. Plasma levels of fatty acids increase post-surgery in infants undergoing cardiac bypass operation to correct congenital heart defects. How a newborn heart responds to increased fatty acid supply remains to be determined. In this study, we examined whether the tissue levels of malonyl CoA decrease to relieve the inhibition on carnitine palmitoyltransferase (CPT) I when the myocardium is exposed to higher concentrations of long-chain fatty acids in newborn rabbit heart. We then tested the contribution of the enzymes that regulate tissue levels of malonyl CoA, acetyl CoA carboxylase (ACC), and malonyl CoA decarboxylase (MCD). Our results showed that increasing fatty acid supply from 0.4 mmol/L (physiological) to 1.2 mmol/L (pathological) resulted in an increase in cardiac fatty acid oxidation rates and this was accompanied by a decrease in tissue malonyl CoA levels. The decrease in malonyl CoA was not related to any alterations in total and phosphorylated acetyl CoA carboxylase protein or the activities of acetyl CoA carboxylase and malonyl CoA decarboxylase. Our results suggest that the regulatory role of malonyl CoA remained when the hearts were exposed to high levels of fatty acids.     

The response of soil solution chemistry in European forests to decreasing acid deposition

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al_tot) and dissolved organic carbon were determined for the period 1995–2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10–20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate () in soil solution; over a 10‐year period (2000–2010), decreased by 52% at 10–20 cm and 40% at 40–80 cm. Nitrate was unchanged at 10–20 cm but decreased at 40–80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca²⁺ + Mg²⁺ + K⁺) and Al_tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10–20 cm, ANC increased in acid‐sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid‐sensitive soils (base saturation ≤20%,  ≤ 4.5) and decreased in better‐buffered soils (base saturation >20%,  > 4.5). In addition, the molar ratio of Bc to Al_tot either did not change or decreased. The results suggest a long‐time lag between emission abatement and changes in soil solution acidity and underline the importance of long‐term monitoring in evaluating ecosystem response to decreases in deposition.     

The role of abscisic acid and salination in the adaptive response of plants to reduced root aeration

Cessation of root aeration to tobacco plants (Nicotiana rustica)growing in half-Hoagland nutrient solution resulted in rapidwilting of the shoot. Plants growing in salinated solutions,however, retained their turgor despite lack of aeration. Thisresistance to aeration stress was associated with increasedconcentration of abscisic acid in the leaves. Maximum amountsof abscisic acid in leaves were reached by the 4th day of salinationand coincided with the maximum resistance to lack of aeration.When the plants were returned to half-Hoagland, leaf-abscisicacid decreased to the presalination level. Resistance to lackof aeration also resulted when plants were pretreated with abscisicacid. We tentatively conclude that resistance to lack of rootaeration reflects adaptation to osmotic stress and is partlydue to an increase in the content of leaf-abscisic acid. ¹ Volcani Institute of Agricultural Research, Bet Dagan, Israel.Present address: Department of Horticulture, Michigan StateUniversity, East Lansing, Michigan 48823, U. S. A. (Received June 12, 1971; )     

Phosphoenolpyruvate carboxykinase of kidney. Subcellular distribution and response to acid–base changes

1. A method for the assay of phosphoenolpyruvate carboxykinase is presented, based on the enzymic determination of the phosphoenolpyruvate produced by the enzyme reaction. 2. The subcellular distribution of phosphoenolpyruvate carboxykinase in the kidney of several animal species resembled the distribution in the liver. 3. The rise in enzyme activity in the kidney cortex of rats made acidotic by feeding with ammonium chloride was not prevented by administration of ethionine or actinomycin. 4. The possibility is suggested that in the kidney acidosis causes activation of an inactive form of the enzyme already present.     

Comparative study of the quantitative determination of kanamycin sulfate in ophthalmic films with a collagen base by microbiological and chemical methods

The results of the comparative study on microbiological and chemical quantitative determination of kanamycin sulfate in the ophthalmic films with the collagen base are presented. The intraocular films prepared with the use of 1 per cent collagen solution contain dexamethasone and kanamycin. The agar diffusion method with Bacillus pumilus NCTC 8241 as the test microbe and the photocolorimetric method based on estimation of the optical density of the colored compound formed after acid hydrolysis of kanamycin with orcinol and ferric chloride were used for the quantitative determination of kanamycin. The results of the quantitative determinations of kanamycin in the films with the two methods did not differ significantly. However, the error of the microbiological method was +/- 3,75 per cent, whereas that of the chemical method was +/- 1.23 per cent or approximately 3 times lower. The time of the analysis decreased from 24 to 1.5-2 h. Moreover, the chemical method is simple and readily reproducible.     

Low and high nucleic acid content bacteria play discrepant roles in response to various carbon supply modes

Planktonic bacteria can be grouped into ‘high nucleic acid content (HNA) bacteria’ and ‘low nucleic acid content (LNA) bacteria.’ Nutrient input modes vary in environments, causing nutrient availability heterogeneity. We incubated them with equal amounts of total glucose added in a continuous/pulsed mode. The pulse-treated LNA bacteria exhibited twice the cell abundance and four times the viability of the continuous-treated LNA, while HNA did not show an adaptation to pulsed treatment. In structural equation modelling, LNA bacteria had higher path coefficients than HNA, between growth and carbon-saving metabolic pathways, intracellular ATP and the inorganic energy storage polymer, polyphosphate, indicating their low-cost growth, and flexible energy storage and utilisation. After incubation, the pulse-treated LNA bacteria contained more proteins and polysaccharides (0.00064, 0.0012 ng cell⁻¹) than the continuous-treated LNA (0.00014, 0.00014 ng cell⁻¹), conferring endurance and rapid response to pulses. Compared to LNA, HNA keystone taxa had stronger correlations with the primary glucose metabolism step, glycolysis, and occupied leading positions to explain the random forest model. They are essential to introduce glucose into the element cycling of the whole community under both treatments. Our work outlines a systematic bacterial response to carbon input.     

Effect of gastrin monoclonal antibody 28.2 on acid response to chemical vagal stimulation in rats

The role of gastrin in mediating the acid response to chemical vagal stimulation was evaluated by intravenous injection of the gastrin monoclonal antibody 28.2 (2.6 mg/rat). The antibody was injected 30 min prior to the administration of vagal stimulants in urethane-anesthetized rats equipped with a double lumen gastric cannula. The gastrin monoclonal antibody 28.2 prevented gastrin-17- but not carbachol-stimulated gastric acid secretion. The gastric acid response to vagal stimulation produced by thyrotrophin-releasing hormone (TRH) injected into the cisterna magna or the dorsal vagal complex and by the GABAB agonist, baclofen, infused intravenously was reduced by 33, 22 and 33% respectively in rats administered with gastrin monoclonal antibody 28.2. These immunoneutralization studies provide evidence that approximately 75% of the acid response to vagal stimulation is not mediated by gastrin in urethane-anesthetized rats.     

Factors controlling cell proliferation and antibody production in mouse hybridoma cells: I. Influence of the amino acid supply

To investigate the influence of medium amino acid resources on hybridoma cell proliferation and monoclonal antibody secretion, we first determined, in two different cell lines, the pattern of amino acid consumption. We then showed that complementation of each cell line by an amino acid solution prepared to cover its needs led in both cases to a marked increase in cell density and monoclonal antibody production. This observation suggests that the amino acid supply is one of the factors limiting cell growth and productivity in typical batch processes, and we demonstrated that a similar limitation occurs in a semicontinuous culture. Finally, we showed that the cell decline observed after a period of amino acid deficiency is not irreversible and that proliferation could be resumed if the required amino acids were added.     

Foraminiferal response to the Northeast Monsoon in the western and southern Arabian Sea

Sediments from the western and southern part of the Arabian Sea were collected periodically in the spring intermonsoon between March and May 1997 and additionally at the end of the Northeast Monsoon in February 1998. Assemblages of Rose Bengal stained, living deep-sea benthic foraminifera, their densities, vertical distribution pattern, and diversity were analysed after the Northeast Monsoon and short-time changes were recorded. In the western Arabian Sea, foraminiferal numbers increased steadily between March and the beginning of May, especially in the smaller size classes (30–63 μm, 63–125 μm). At the same time, the deepening of the foraminiferal living horizon, variable diversity and rapid variations between dominant foraminiferal communities were observed. We interpret these observations as the time-dependent response of benthic foraminifera to enhanced organic carbon fluxes during and after the Northeast Monsoon. In the southern Arabian Sea, constant low foraminiferal abundances during time, no distinctive change in the vertical distribution, reduced diversity, and more stable foraminiferal communities were noticed, which indicates no or little influence of the Northeast Monsoon to benthic foraminifera in this region.     

Roles of diet and the acid tolerance response in survival of common Salmonella serotypes in feces of finishing pigs

The persistence of Salmonella in the environment is an important factor influencing the transmission of infection in pig production. This study evaluated the effects of acid tolerance response (ATR), organic acid supplementation, and physical properties of feed on the survival of a five-strain Salmonella mixture in porcine feces held at 4 and 22°C for 88 days. Acid-adapted or non-acid-adapted nalidixic acid-resistant Salmonella strains were used to inoculate feces of pigs fed four different diets, which consisted of a nonpelleted, finely ground meal feed or a finely ground, pelleted feed that was left unsupplemented or was supplemented with K-diformate. Organic acid supplementation and physical properties of feed markedly influenced Salmonella survival, but the effects were highly dependent on storage temperature; survival was unaffected by ATR. The most pronounced effects were observed at 22°C, a temperature similar to that of finishing pig houses. The supplementation of meal diets with K-diformate significantly reduced the duration of survival (P < 0.1) and increased rates of decline (P < 0.0001) of salmonellae in feces compared to survival in feces of pigs fed unsupplemented meal. The pelleting of feed, compared to feeding meal, significantly reduced (P < 0.1) the duration of survival in feces held at 22°C. Only minor effects of feed form and acid supplementation on survivor numbers were observed at 4°C. Differences in the fecal survival of Salmonella could not be related to diet-induced changes in fecal physiochemical parameters. The predominant survival of S. enterica serovar Typhimurium DT193 and serotype 4,[5],12:i:- in porcine feces demonstrates the superior ability of these serotypes to survive in this environment. Fecal survival and transmission of Salmonella in pig herds may be reduced by dietary approaches, but effects are highly dependent on environmental temperature.