FITC-labeled lectins and calcofluor white ST as probes for the investigation of the molecular architecture of cell surfaces. Studies on conjugatophycean species

Summary In a screening program with 7 FITC-labeled lectins as probes, ConA receptors were identified in all of the 28 members of theConjugatophyceae, being under investigation. In nearly all of them RCA₁₂₀ receptors, too, are expressed. In 3 species only, PNA receptors, and in 2 species UEA receptors have been detected. No binding of DBA, SBA, and WGA was observed. The receptors for ConA, RCA₁₂₀, and UEA were shown to be associated with different molecules. Each lectin exhibits a unique and specific binding pattern, both chemically, as well as with regard to the topographic distribution on cell surfaces. While ConA receptors predominantly are associated with constituents of the cell wall, RCA₁₂₀ receptors mostly form part of the surrounding mucilage; the same holds for UEA receptors. Besides a variability of topographic distribution and species-to-species variation, a cell-to-cell variation exists in many species, suggesting that the expression of a lectin receptor is due to the developmental state of the cell and/or depends on external stimuli. In conclusion, we may point out, that FITC-labeled lectins turned out to be extremely useful probes for the investigation of the molecular architecture of cell walls. Calcofluor white ST binding to fibrillar polysaccharides (most probably cellulose) was shown to be inhibited by external incrustations of the cell wall. One species does not show any reaction with calcofluor white ST at all.     

Dynamics of Docosahexaenoic Acid Metabolism in the Central Nervous System: Lack of Effect of Chronic Lithium Treatment

Using a method and model developed in our laboratory to quantitatively study brain phospholipid metabolism, in vivo rates of incorporation and turnover of docosahexaenoic acid in brain phospholipids were measured in awake rats. The results suggest that docosahexaenoate incorporation and turnover in brain phospholipids are more rapid than previously assumed and that this rapid turnover dilutes tracer specific activity in brain docoshexaenoyl-CoA pool due to release and recycling of unlabeled fatty acid from phospholipid metabolism. Fractional turnover rates for docosahexaenoate within phosphatidylinositol, choline glycerophospholipids, ethanolamine glycerophospholipids and phosphatidylserine were 17.7, 3.1, 1.2, and 0.2 %.h^–1, respectively. Chronic lithium treatment, at a brain level considered to be therapeutic in humans (0.6 mol.g^–1), had no effect on turnover of docosahexaenoic acid in individual brain phospholipids. Consistent with previous studies from our laboratory that chronic lithium decreased the turnover of arachidonic acid within brain phospholipids by up to 80% and attenuated brain phospholipase A₂ activity, the lack of effect of lithium on docosahexaenoate recycling and turnover suggests that a target for lithium's action is an arachidonic acid-selective phospholipase A₂.     

Elsinochrome A production by the bindweed biocontrol fungus Stagonospora convolvuli LA39 does not pose a risk to the environment or the consumer of treated crops

Biological control as an alternative to chemical pesticides is of increasing public interest. However, to ensure safe use of biocontrol methods, strategies to assess the possible risks need to be developed. The production of toxic metabolites is an aspect which has so far largely been neglected in the risk assessment and the registration process for biocontrol products. We have evaluated the risks of elsinochrome A (ELA) and leptosphaerodione production by the fungus Stagonospora convolvuli LA39, an effective biocontrol agent used against bindweeds. The toxicity of the two metabolites to bacteria, protozoa, fungi and plants was evaluated in in vitro assays. The most sensitive bacteria and fungi were already affected at 0.01-0.07 microM ELA, whereas plants were far less sensitive. Leptosphaerodione was less toxic than ELA. Subsequently, it was investigated whether ELA is present in the applied biocontrol product or LA39-treated bindweed and crop plants. In plants ELA was never detected and in the biocontrol product the ELA concentration was far too low to have toxic effects even on the most sensitive organisms. We conclude that the production of ELA by biocontrol strain LA39 does not pose a risk to the environment or to the consumer.     

Golden hamsters are nocturnal in captivity but diurnal in nature

Daily activity rhythms are nearly universal among animals and their specific pattern is an adaptation of each species to its ecological niche. Owing to the extremely consistent nocturnal patterns of activity shown by golden hamsters (Mesocricetus auratus) in the laboratory, this species is a prime model for studying the mechanisms controlling circadian rhythms. In contrast to laboratory data, we discovered that female hamsters in the wild were almost exclusively diurnal. These results raise many questions about the ecological variables that shape the activity patterns in golden hamsters and the differences between laboratory and field results.     

Intact carcasses as enrichment for large felids: Effects on on‐ and off‐exhibit behaviors

Reducing stereotypic behaviors in captive animals is a goal for zoological institutions worldwide, and environmental enrichment is one tool commonly used to meet that end. Behavioral needs associated with feeding, however, are often neglected in large carnivores. To address these needs, I tested the effects of calf carcasses as enrichment for large felids. Over 14 weeks, I provided nine animals with up to seven intact carcasses. The cats were housed at Toledo Zoo, Potawatomi Zoo, and Binder Park Zoo. Animals were observed off and on exhibit for changes in feeding, natural, stereotypic, active, and inactive behaviors. I compared treatment behaviors with behaviors observed during a baseline period in which the animals were fed traditional processed diets. For these nine cats, carcass provision decreased off‐exhibit stereotypic behaviors but had little impact on on‐exhibit behaviors. Zoo Biol 21:37–47, 2002. © 2002 Wiley‐Liss, Inc.     

Attitudes of Dutch Citizens toward Sow Husbandry with Regard to Animals,Humans, and the Environment

The pig industry is struggling with negative attitudes of people toward sow husbandry. To be able to respond to these attitudes, the pig industry first has to understand people’s attitudes. The first objective of this study was to determine the attitudes of Dutch people toward sow husbandry with regard to animals, humans, and the environment. The second objective was to group people based on their attitudes toward sow husbandry and determine and compare the socio-demographic characteristics of these groups. An online survey was conducted in the Netherlands and there were 1,607 respondents. On average, respondents had negative attitudes toward all issues defined in this study. The most negative attitudes were toward the effect on both animals and consumers of the use of antibiotics, the number of animals kept per square meter, the possibility for animals to go outside, food safety risks, public health risks, and environmental waste. The findings indicate the importance of considering all the issues identified in this study during the process of developing measures to improve people’s attitudes toward sow husbandry. Respondents could be divided into four clusters; each cluster represented different attitudes toward sow husbandry and had different socio-demographic characteristics. This makes it possible for the pig industry to assign people with specific socio-demographic characteristics to one of the clusters and predict their attitudes toward sow husbandry. Knowledge of these attitudes enables the pig industry to predict how different groups of people will respond to different animal welfare measures. Results of this study are therefore useful for the pig industry to help improve people’s attitudes toward sow husbandry.     

Male golden hamsters (<Emphasis Type="Italic">Mesocricetus auratus</Emphasis>) are more reactive than females to a visual predator cue

In most species of small mammals, males are exposed to higher levels of risk than females because they compete for mates, travel greater distances to find and procure mates, and/or defend a territory. This suggests that males and females might have different responses to risky situations, such as the presence of a predator. We tested responses to a visual predator cue (an owl silhouette) in male and female golden hamsters (Mesocricetus auratus). In a laboratory arena, there was no significant sex difference in the latency to enter the burrow or time spent in the burrow immediately after exposure to the owl silhouette. Males, however, were less likely to be active during the 3-min period following the animal’s exposure to the silhouette, indicating that male golden hamsters are more wary after exposure to an aerial predator cue than females. Most studies of responses to predators or predator cues have not considered sex differences, but our results show that males and females may have quite different responses to predator cues. Further work should be done to characterize and quantify sex differences in response to predators or predator cues.