Non-invasive measurement of faecal glucocorticoid metabolites in Upland Geese <Emphasis Type="Italic">Chloephaga</Emphasis><Emphasis Type="Italic">picta</Emphasis>

Glucocorticoid (GC) hormones rise in response to stressors, including natural events including weather or predator presence, and human activities, such as hunting, scientific research or recreational visits. However, because blood sampling itself causes stress and is dangerous or even impossible in some wildlife species, feedback-free methods for GC determination are needed to assess stress in these animals. Faecal GC analyses have thus gained interest. Here, we validate a non-invasive method to estimate the physiological stress in the Upland goose Chloephaga picta. An adrenocorticotropin hormone (ACTH) challenge was conducted in captive adults (female and male), and droppings were collected before, during and after the experiment. Corticosterone metabolite (CM) secretion in response to the ACTH challenge was measured with several enzyme immunoassays (EIA) to find the most appropriate test. We used CM levels during the periods before and after the experiment as control data. An EIA for 11-oxoetiocholanolone achieved the highest response to the ACTH challenge and also reflected a stress response to unfamiliar environment. Furthermore, CM concentrations of dry samples were highly correlated with the corresponding non-dried (frozen) samples. The data suggest that this method is appropriate to measure the stress in Upland geese, and that samples can be stored either frozen or dry form.     

Activity of cytochrome P-450 in whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> and pike <Emphasis Type="Italic">Esox lucius</Emphasis> from subarctic water bodies exposed to waste water of mining enterprises

The response of hydroxylase activity of cytochrome P-450 from the microsomes of fish liver depends on fish species and on the kind of pollution. Differences in activity of the enzyme in whitefish Coregonus lavaretus and Pike Esox lucius depend on differences in ecology and in sensitivity of species to industrial effluents. Whitefish reacted to pollution by decrease in the activity of cytochrome P-450. In pike the activity of the enzyme increased under the influence of industrial wastewater. Males of both species are less resistant than females to the aforementioned pollutants. With consideration to the obtained results, the determination of activity of cytochropme P-450 may be recommended as the indicator of pollution level of the aquatic environment with industrial waste products, including those containing heavy metals.     

The influence of predator regime on reproductive traits in <Emphasis Type="Italic">Gammarus</Emphasis> <Emphasis Type="Italic">pulex</Emphasis> populations

Selection on traits conferring reduced predation may be opposed by selection on other traits associated with reproduction. Here, we examined the hypothesis that traits associated with reproduction in Gammarus pulex are driven by predation. We studied G. pulex originating from ponds with two different kinds of predator regimes: (1) ponds with fish—often large, non-gap-limited predators and (2) ponds without fish where invertebrates are the dominant predators—often small, gap-limited predators with a much more restricted prey size range. We examined the body size of males and females in G. pulex amplexus pairs originating from fish and fishless ponds. We also examined, in the laboratory, their mating success, the number of offspring per female and offspring mortality under different rearing conditions, with or without fish cue. Mating success, defined as the percentage of amplexus pairs that produced live offspring, was higher for G. pulex from fishless ponds independent of rearing condition. Individuals from fish ponds were larger and they produced a higher number of offspring which tended to be related to female body size. Offspring mortality was higher in populations from fish ponds compared to populations from fishless ponds. Despite the higher offspring mortality, females from fish ponds had a higher number of offspring alive after 13 weeks, which is the approximate time it takes for G. pulex to reach maturity. Our data imply that no trade-off between reducing body size to reduce mortality caused by fish and maximising reproductive success exist in G. pulex from fish ponds. The strategy with many offspring may be the correct strategy in fishponds where predation pressure generally is higher than in fishless ponds.     

Magnetic field perception in the Rainbow Trout, <Emphasis Type="Italic">Oncorhynchus</Emphasis> <Emphasis Type="Italic">mykiss</Emphasis>

In this study, we present evidence for the perception of different magnetic field parameters in a facultative anadromous fish species of the family Salmonidae. Magnetic field perception of the rainbow trout, Oncorhynchus mykiss, was demonstrated with a heartbeat conditioning test. The electrocardiogram was measured with subcutaneously inserted silver wire electrodes in freely swimming fish. We demonstrate a conditioned response (i.e. a significant longer interval between two heartbeats) to an intensity/inclination shift for three adult and two juvenile rainbow trouts. Moreover, a conditioned response to a 90° direction shift was demonstrated for three adult and two juvenile trouts. These findings support the hypothesis that the rainbow trout is able to perceive different magnetic field parameters. Furthermore, the study demonstrates magnetosensation in different developmental stages in the rainbow trout, i.e. juvenile and adult fish.     

<Emphasis Type="Italic">Ochroconis calidifluminalis</Emphasis>, a Sibling of the Neurotropic Pathogen <Emphasis Type="Italic">O. gallopava</Emphasis>, Isolated from Hot Spring

Two strains resembling the neurotropic fungus Ochroconis gallopava were isolated from hot spring river water (IFM 54738 and IFM 54739). The isolates showed optimal growth at 42°C, while the maximum growth temperature was 49°C, thus having temperature relationships similar to those of O. gallopava. Colonies were light olive green, with a color change to dark reddish brown after several passages, which was also observed in O. gallopava. Conidia were indistinguishable from those of O. gallopava. The antifungal susceptibility profile of the isolates was also similar to that of O. gallopava, except for a lower susceptibility to micafungin. The two isolates had 100% homologous rRNA genes including the internal transcribed spacer (ITS) region and the D1/D2 region of the large subunit. The gene fragments, as O. gallopava, could be amplified with species-specific rDNA primers, and loop-mediated isothermal amplification designed for O. gallopava yielded positive results in the two isolates. However, homologies with O. gallopava in ITS and D1/D2 regions were 79.2 and 95.9%, respectively, widely exceeding generally accepted species boundaries. These differences were corroborated in virulence tested in experimental infection. The two isolates did not kill a mouse even until 28 days. However, mortalities of four O. gallopava strains ranged from 40 to 100%. The new isolates mainly affected the kidneys; whereas O. gallopava had a strong preference for the brain. We therefore propose a new species, Ochroconis calidifluminalis, for the two isolates.     

Muscular architecture of <Emphasis Type="Italic">Milnesium tardigradum </Emphasis>and <Emphasis Type="Italic">Hypsibius </Emphasis>sp. (Eutardigrada,Tardigrada) with some data on <Emphasis Type="Italic">Ramazottius oberhaeuseri</Emphasis>

The architecture of the musculature of the eutardigrade species Milnesium tardigradum Doyère, 1840, Hypsibius sp. and Ramazzottius oberhaeuseri (Doyère in Ann Sci Nat Zool Sér 2(14):269–369, 1840) is investigated by phalloidin staining and confocal laser scanning microscopy. There are methodological problems in staining eutardigrades due to physiological alterations under stress (anhydrobiosis) and due to penetration problems of the cuticle. It is helpful to fix specimens in the state of asphyxy, where animals are stretched following an oxygen shortage in their environment. The musculatures of all three species correspond in their general architecture, but differ in detail, such as in the number of muscles. All muscles are isolated muscle strands. There are on each body side two dorsal and one ventral muscle strands, in addition to a system of dorsoventral, lateral and lateroventral muscles. Seven median ventral attachment points give rise to dorsoventral, ventrolateral and appendage muscles. The appendages receive several muscles originating dorsally and ventrally. The number of muscles and the arrangement differ in each appendage. The fourth appendage shows the greatest differences with a far smaller number of muscles compared to other species. The musculature shows comparably few strict segmental patterns, for example, the musculature of each appendage differs from the other ones. By comparison with literature data on the same species and data of Macrobiotus hufelandi it can be shown that eutardigrades have a roughly comparable muscular architecture, but that there are several differences in detail. Dedicated to Professor Westheide on the occasion of his 70th birthday.     

Relationship between glucose catabolism and xanthan production in <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis>

Two genes involved in central carbon metabolism were inactivated to modulate intracellular glucose 6-phosphate and to evaluate its effects on xanthan production in wild-type Xanthomonas oryzae pv. oryzae. Upon the inactivation of the phosphogluconate dehydratase gene (edd), intracellular glucose 6-phosphate increased from 0.05 to 1.17 mmol/g (dry cell wt). This was accompanied by increased xanthan production of up to 2.55 g/l (culture medium). In contrast, inactivation of 6-phosphogluconate dehydrogenase gene (gndA) did not influence intracellular glucose 6-phosphate nor xanthan production. The intracellular availability of glucose 6-phosphate is proposed as a rate-limiting factor in xanthan production, and it may be possible to increases production of xanthan by modulating the activities of enzymes in central carbon metabolism.     

Seasonality of glycogen phosphorylase activity in crucian carp (<Emphasis Type="Italic">Carassius carassius</Emphasis> L<Emphasis Type="Italic">.</Emphasis>)

Seasonal changes in the activity of glycogen phosphorylase (GP), a rate-limiting enzyme of glycogen degradation, were examined in an anoxia-tolerant fish species, the crucian carp (Carassius carassius L.). In muscle and brain, the activity of GP remained constant throughout the year when tested at 25°C. In contrast, the activities of liver and heart GP displayed striking increases in summer. When seasonal temperature changes are taken into account, the activity of GP during the anoxic mid-winter is only 4–6% of its summer time activity in the muscle, heart and liver, and 13% in brain. In winter-acclimatized fish, experimental anoxia (1–6 weeks) caused sustained depression of the GP activity in heart and gills. In liver and muscle, a transient depression of GP activity occurred during the first week of anoxia but later GP activity recovered back to the normoxic level. GP of the brain was completely resistant to anoxia. In all studied tissues, the constitutive activity of GP is more than sufficient to degrade glycogen deposits during winter anoxia without anoxia-induced activation of GP. The seemingly paradoxical summer-time increase in the activity of liver and heart GP could be related to active life-style of the summer-acclimatized fish (growth, reproduction), the increased demand of energy and molecular precursors of anabolic metabolism being satisfied by preferential degradation of glycogen. The high glycogen content of winter-acclimatized crucian carp is not associated with the elevated GP activity or anoxic activation of GP.     

Effects of sugars and growth regulators on <Emphasis Type="Italic">in vitro</Emphasis> growth of <Emphasis Type="Italic">Dactylorhiza</Emphasis> species

The influence of sugars and growth regulators on shoot and root growth of Dactylorhiza species was studied under in vitro conditions. The seedling development was stimulated with the application of glucose and sucrose at concentration of 10 g dm⁻³ each. The improvement of shoot growth rate and shoot length was enhanced by cytokinins N ⁶-(2-isopentenyl)adenine or N ⁶-benzyladenine and their combination with auxin indolebutyric acid (IBA). The root growth rate and root length of seedlings increased in the presence of IBA and α-naphthaleneacetic acid. Individual Dactylorhiza species showed statistically significant differences in shoot and root development depending on sugar and growth regulator combinations.     

Potential long-term storage of the predatory mite <Emphasis Type="Italic">Phytoseiulus</Emphasis><Emphasis Type="Italic">persimilis</Emphasis>

Increasing the ability to store mass-reared natural enemies during periods or seasons of low demand is a critical need of the biocontrol industry. We tested the hypothesis that chemicals can enhance long-term cold storage of a predatory mite Phytoseiulus persimilis Athias-Henriot. The research objective was to determine the effect of cryoprotectant and carbohydrate chemicals on in-storage survival of predators. In-storage survival at 8°C was greater for predators sprayed with glycerol (5%, v/v) or glucose (10% and 20%, v/v) than with water spray controls. After 74 days in the cryoprotectant experiment, predator survival declined to 11.5% in the 5% glycerol treatment and 7.8% in the water spray control. After 88 days in the carbohydrate experiment, predator survival declined to 22% in the 20% glucose treatment and 2% in the water spray control. Although many individuals expired within 50 days in both experiments, a few females survived more than 200 days. This research suggests that select cryoprotectants and carbohydrates have a limited capacity to facilitate long-term storage of P. persimilis.     

Development of a species-specific fractionation equation for Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis> (L.)): an experimental approach

A species-specific fractionation equation for Arctic charr (Salvelinus alpinus (L.)) was developed experimentally for use in ecological studies of temperature-driven phenologies for the species. Juvenile Arctic charr were reared in controlled conditions at different temperatures (2–14°C), with three replicates of each temperature. Otoliths from the fish and water samples from the chambers were analysed for oxygen isotope composition and used to estimate temperature-dependent fractionation equations relating the isotopic ratio to rearing temperature. A linear and a second order polynomial relationship were estimated and validated using comparable Arctic charr data from another study. Temperatures predicted using the polynomial equation were not significantly different from recorded experimental temperatures, whereas with the linear equation there were significant differences between the predicted and measured temperatures. The polynomial equation also showed the least bias as measured by mean predictive error. Statistical comparisons of the polynomial fractionation equation to a similarly estimated equation for brook charr (Salvelinus fontinalis (Mitchill)) indicated significant differences. Results imply the need for species-specific fractionation equations, even for closely related fish. Results further suggest the polynomial form of the fractionation equation will facilitate more accurate characterisation of water temperatures suitable for use in ecological studies of temperature-driven phenologies of Arctic charr.     

Effect of <Emphasis Type="Italic">Caryophyllaeus laticeps</Emphasis> (Cestoda,Caryophyllidea) upon activity of digestive enzymes in bream

The activities of the main digestive hydrolases were comparatively studied in bream infected and noninfected with cestodes Caryophyllaeus laticeps (Pallas, 1781). It was shown that enzyme activities are distributed in the fish intestine in an irregular manner; the gradient of protease and lipase activities along the gut is presented. Following the infection of bream by cestodes, the activities of the studied enzymes decreased and the percentages of activities of various proteinase subclasses changed. No relation between the distribution of worms along the intestine and the levels of activities of digestive hydrolases was revealed.     

Detecting <Emphasis Type="Italic">Suaeda salsa</Emphasis> L<Emphasis Type="Italic">.</Emphasis> chlorophyll fluorescence response to salinity stress by using hyperspectral reflectance

Measurements of chlorophyll fluorescence and hyperspectral reflectance were used to detect salinity stress in Suaeda salsa L., beach of Dongtai, Jiangsu Province, China. Three experimental sites were used in our study, which belong to low salinity, middle salinity and high salinity. The results showed that leaf chlorophyll fluorescence changed along salinity gradient. To select the sensitive hyperspectral ranges of leaf chlorophyll fluorescence, the correlationship between leaf chlorophyll fluorescence and hyperspectral reflectance was regressed and analyzed. Statistical results indicated that the 680 and 935 nm were the most sensitive hyperspectral bands for estimating leaf chlorophyll fluorescence. Then, 11 relative hyperspectral indices were selected based on the sensitive bands and previous literature. (R ₆₈₀ − R ₉₃₅)/(R ₆₈₀ + R ₉₃₅) and R ₆₈₀/R ₉₃₅ have higher correlationship coefficient (R) and lower root mean square error, may be used for detecting chlorophyll fluorescence, such as F _o, F _m, F _v/F _m, qP, and ΦPSII, while NPQ may be detected by (R ₇₈₀ − R ₇₁₀)/(R ₇₈₀ − R ₆₈₀). These results suggest that chlorophyll fluorescence of halophyte response to salinity stress could be identified by remote sensing.     

Alternative mating tactics of the gobiid fish <Emphasis Type="Italic">Bathygobius</Emphasis><Emphasis Type="Italic">fuscus</Emphasis>

The reproductive ecology of the gobiid fish Bathygobius fuscus was studied at Nobeoka, Miyazaki, Japan. Males of this species maintain small rock holes as a nest and females spawn an egg mass on the wall of the nest. The males employed two forms of mating tactic: nest holding and sneaking. A nest holder stayed in the nest and waited for a female to visit, whereas a sneaker intruded into a nest while a pair was engaged in reproduction. Males larger than 55 mm standard length were always nest holders; those of smaller size employed both tactics. As the larger males excluded the smaller males, the latter did not occupy a nest hole. With a decrease in the number of larger males, smaller males changed their mating tactic from sneaking to nest holding. The results suggest that male Bathygobius fuscus adopt a conditional strategy whereby they change their tactic depending on their social status. Electronic Publication     

Mapping species differences for adventitious rooting in a <Emphasis Type="Italic">Corymbia torelliana</Emphasis> × <Emphasis Type="Italic">Corymbia citriodora</Emphasis> subspecies <Emphasis Type="Italic">variegata</Emphasis> hybrid

Quantitative trait loci (QTL) detection was carried out for adventitious rooting and associated propagation traits in a second-generation outbred Corymbia torelliana × Corymbia citriodora subspecies variegata hybrid family (n = 186). The parental species of this cross are divergent in their capacity to develop roots adventitiously on stem cuttings and their propensity to form lignotubers. For the ten traits studied, there was one or two QTL detected, with some QTL explaining large amounts of phenotypic variation (e.g. 66% for one QTL for percentage rooting), suggesting that major effects influence rooting in this cross. Collocation of QTL for many strongly genetically correlated rooting traits to a single region on linkage group 12 suggested pleiotropy. A three locus model was most parsimonious for linkage group 12, however, as differences in QTL position and lower genetic correlations suggested separate loci for each of the traits of shoot production and root initiation. Species differences were thought to be the major source of phenotypic variation for some rooting rate and root quality traits because of the major QTL effects and up to 59-fold larger homospecific deviations (attributed to species differences) relative to heterospecific deviations (attributed to standing variation within species) evident at some QTL for these traits. A large homospecific/heterospecific ratio at major QTL suggested that the gene action evident in one cross may be indicative of gene action more broadly in hybrids between these species for some traits.     

Occurrence of the parasitic sea lamprey<Emphasis Type="Italic">Petromyzon marinus</Emphasis> on western North Atlantic right whales <Emphasis Type="Italic">Eubalaena glacialis</Emphasis>

Few data exist on the marine distribution and host organisms of the parasitic sea lamprey, Petromyzon marinus. Some observers have speculated that cetaceans serve as hosts for these fish based on scars, but few lamprey – cetacean interactions have been described in detail in the literature. Here we discuss 35 previously unreported records of sea lampreys that were observed while attached to western North Atlantic right whales, Eubalaena glacialis, during the period 1984 – 2002. Of these observations, 11 were photographically documented with images of sufficient quality to identify the lamprey as P. marinus based on morphological characteristics. The majority of the attachments were recorded in the Bay of Fundy during the summer months when P. marinus are preparing to spawn. It is unknown how lampreys might benefit from this association or what cost may be incurred by their right whale hosts. Feeding and transport are two possible reasons for the attachments.     

Strong body mass decrease of the invasive clam <Emphasis Type="Italic">Corbicula fluminea</Emphasis> during summer

The filter-feeding clam Corbicula fluminea has widely spread from its Asiatic origin into freshwater habitats on several continents, where it often has a considerable impact on ecosystem processes. The present study was stimulated by the observation that C. fluminea can experience mass mortality during warm summers, even when temperatures are still far below the lethal level. We hypothesized that starvation due to low food quantities during summer is a main factor in this context. In order to test nutritional conditions in an environment where summer mortality occurred, the clams’ body mass was tracked in river bypass systems installed at the Lower River Rhine (Germany and The Netherlands). Two food levels were adjusted in the bypass channels: one corresponding to the original chlorophyll level in the river (ambient food) and one with a chlorophyll a level reduced by about 50% (low food). The clams kept at the ambient food level increased their shell length during summer, although growth rates decreased at low food levels in the River Rhine in late summer. In contrast to shell length, body mass decrease in late summer cumulated in 94% reduction from August until October. This trend was enhanced by the experimental food reduction, i.e., clams kept in the low food level treatments weighed 60% less than the clams in the ambient food treatment at the end of summer. However, mortality was low in both treatments. The data demonstrate a high plasticity in the body mass of C. fluminea. The corresponding possibility to respire body mass can be seen as one strategy to survive longer starvation periods.