Habitat correlates of the distribution and biomass of Seychelles' reef fishes

Synopsis Relationships between quantitative measures of habitat type and the biomass of Chaetodon, Scarus and Parupeneus species were investigated across 35 reef sites in the Inner Seychelles Group. Multiple regression was used to determine the proportion of variance in biomass between sites which could be explained by depth, exposure, vertical relief, topographic complexity, live coral cover, coral rubble cover, rock cover, sand cover, underlying carbonate substrate, underlying sand substrate, underlying rock substrate and an index of fishing intensity. A significant proportion of the variance in biomass was explained by habitat variables and the index of fishing intensity for 7 of 12 Chaetodon species (23–52% of variance explained), 3 of 6 Parupeneus species (33–40%), and 10 of 13 Scarus species (14–46%). Within genera, different groups of habitat variables explained the variance in biomass for different species and, of the variables studied, only the proportion of underlying sand substrate failed to explain a significant proportion of the variance in biomass for any species. Quantitative relationships between the biomass of Chaetodon and habitat were often in accordance with those suggested by previous studies of their ecology, life-history and distribution at other Indo-Pacific locations. However, the habitat associations of the Parupeneus and some Scarus species have not been studied at other locations and clearly warrant further investigation. It was concluded that habitat was an important determinant of the distribution of many Seychelles reef fishes, but that the habitat variables examined were rarely the most important determinant of biomass. However, the inclusion of a procedure to collect habitat data provided a useful means by which to reduce the unexplained variance associated with visual census biomass estimates and therefore improves the possibility of elucidating the effects of other factors on the biomass of Seychelles reef fishes.     

Enhancement of sporulation in species of Bipolaris, Curvularia, Drechslera, and Exserohilum by growth on cellulose-containing substrates

Nine species of Bipolaris, Curvularia, Drechslera, and Exserohilum were compared for sporulation on agar media and for enhancement of sporulation by growth on four cellulose-containing substrates (index card, filter paper, cheesecloth, cotton fabric). On two natural and one synthetic agar media, sporulation varied from profuse to nonexistent among three isolates of each species. Growth of all species on cellulose substrates resulted in large and significant increases in sporulation. Growth on index card pieces often provided the greatest increases, but no single substrate was superior for all species, and significant substrate × isolate interactions were observed within species. Overlay of filter paper onto whole colonies in agar plates resulted in 2 to 18-fold increases in sporulation for eight of nine species and production of spores in sufficient quantity for most experimental purposes. Overlay of soil dilution plates with filter paper to promote sporulation of colonies enabled detection of B. spicifera, B. hawaiiensis, C. lunata, and E. rostratum at relatively low population levels (≤1.3 × 10³ colony-forming units per gram of soil) in samples of a naturally infested soil. Results indicate that enhancement of sporulation by growth of species of Bipolaris, Curvularia, Drechslera, and Exserohilum on cellulose substrates may facilitate (i) their identification in culture, (ii) production of spores at relatively high concentrations, and (iii) detection and enumeration of these fungi in soil.     

Foraging activity and behaviour of two goatfish species (Perciformes: Mullidae) at Fernando de Noronha Archipelago, tropical West Atlantic

The goatfishes (Mullidae) include about 50 bottom-foraging fish species. The foraging activity of the yellow goatfish, Mulloidichthys martinicus, and the spotted goatfish, Pseudupeneus maculatus, was studied comparatively at Fernando de Noronha Archipelago, off coast of Northeast Brazil tropical West Atlantic. Pseudupeneus maculatus fed over a larger variety of substrate types, had lower feeding rate, roamed more per given time, spent less time in a feeding event, and displayed a more diverse repertoire of feeding modes than M. martinicus. The differences in the foraging activity and behaviour between the two species possibly minimize a potential resource overlap, as already recorded for other sympatric mullids. Pseudupeneus maculatus had lower feeding rate most likely because it feeds on larger items, and roamed over greater distance per time. Possibly this is because it foraged over a greater variety of substrate distributed over a larger area than that used by M. martinicus. Notwithstanding the overall morphological and behavioural similarity of goatfishes in general, they do differ in their substrate preferences and foraging activity, which indicates that these fishes should not be simply considered generalized bottom foragers.     

The distribution of submerged aquatic macrophyte biomass in a eutrophic stream,Badfish Creek: the effect of environment

The distribution of biomass of the macrophyte community in Badfish Creek was examined in three sections (A–C) totaling ten kilometers. Biomass samples were taken in a stratified-random manner, with sediment characteristics, depth, current velocity and incident light measured at each site to correlate individual biomass samples with environmental factors. Total community biomass decreased in the downstream section (C), with the biomass ofElodea canadensis decreasing abruptly below section A. The only environmental factors which were correlated with the decrease in macrophyte community biomass, especially that ofPotamogeton pectinatus, in section C was the increase in substrate heterogeneity and sand substrates which lacked surface gravel. The change in substrate was related to channelization. Considering the stream as a whole, the biomass of the dominant species,Potamogeton pectinatus, was correlated with incident light. Other species present wereCeratophyllum demersum andCladophora glomerata. Analysis of riparian vegetation type indicates that tree cover significantly reduced macrophyte biomass by incident light reduction.     

Biodiversity patterns of macro-epifauna on different lamina parts of Laminaria digitata and Saccharina latissima collected during spring and summer 2004 in Kongsfjorden, Svalbard

The epifauna associated with two of the most common species of kelp in the Arctic, Laminaria digitata (Hudson) Lamouroux, 1813 and Saccharina latissima (Linnaeus) Lane, , Mayes, Druehl and Saunders 2006 [synonym: L. saccharina (Linnaeus) Lamouroux, 1813] were examined in Kongsfjorden, Svalbard. The aim of this study was to test whether species richness of epifauna was influenced by seasonality of recruitment supply (spring and summer) or by age of the substrate (lamina). From 20 algae specimens (ten—L. digitata, ten—S. latissima), a total of 27 epifaunal taxa were identified with bryozoans as the most species-rich group. Total species richness ranged from one to nine species per lamina. No significant difference in species richness was observed between the two kelp species. In both macroalgae, more epifauna taxa were registered on lamina in May (mean 6) than in August (mean 3). This indicates that the time chosen for sampling had a significant impact on the species richness pattern. The number of epifaunal species was significantly negatively correlated with increasing age of the lamina. There are indications that diversity of the epifauna on lamina is influenced to a large extent by substrate (lamina) surface area, environmental stress and the presence of meroplankton in the water column.     

On the ecology of Cephalodella

A material consisting of 66 species of Cephalodella (Rotifera), from diverse waters in south and central Sweden, was analyzed to reveal their possible relationships to substrate and habitat. Most species preferred periphytic environments. Most species have a broad ecological range, only a few being bog specialists. An artificial substrate, white cotton, was colonized by several species, even some without eyes.     

Effects of cell entrapment on growth rate and metabolic activity of pure cultures commonly found in biological wastewater treatment

The effects of cell entrapment on the growth rate and metabolic activity of major groups of bacteria (betaproteobacteria and gammaproteobacteria) in biological municipal wastewater treatment were investigated. Three different cell entrapment media (alginate, carrageenan and polyvinyl alcohol) and three cell-to-matrix ratios (0.1%, 0.2% and 0.6%, w v⁻¹) were examined. Representative species of betaproteobacteria were Alcaligenes faecalis and Comamonas testosteroni whereas Pseudomonas putida was a gammaproteobacteria species studied. Free (non-entrapped) cells were included in the study for comparative purpose. Results indicated that the entrapment, type of entrapment media, and cell-to-matrix ratio had significant effects on the growth and metabolic activity of major groups of bacteria in wastewater treatment. Polyvinyl alcohol entrapped cells had the highest specific growth and specific substrate utilization rates. Increase of cell-to-matrix ratio (from 0.1% to 0.2% or 0.6%) did not improve the specific growth and specific substrate utilization rates. The relative performances provided by different entrapment media of the three species studied were quite consistent. This study showed that the suitable choices of entrapment media and cell-to-matrix ratio are important but similar for major groups of bacteria in wastewater treatment.     

Brachyurins, Serine Collagenolytic Enzymes from Crabs

The properties of brachyurins, proteolytic enzymes belonging to a new subfamily of chymotrypsin-like proteases, are considered. These enzymes, found in various species of crustacean, exhibit mixed substrate specificity and a marked collagenolytic activity. The enzymatic and physicochemical properties of brachyurins I and their primary and spatial structures are discussed in detail. A separate chapter is devoted to the preparations of collagenases from the hepatopancreas of king crab: their action on the damaged skin and use in medicine.     

Differential Patterns of Constitutive Intracellular Laccases of the Vegetative Phase of Pleurotus Species

The constitutive intracellular laccase activity of ten strains of Pleurotus spp. was determined in vitro and by zymograms, using different substrates. Differences in the in vitro activities were observed between all the strains; however, zymogram patterns were only similar for strains within same species, independently of any of the three substrate (2,6-dimethoxyphenol, p-anisidine or o-tolidine) used. The differences observed in the number and positions of the isoforms in the gel suggest that laccase zymograms can be used to differentiate species of this organism.     

On the ecology of Lecane (Rotifera)

A material consisting of 49 taxa of Lecane (Rotifera), from diverse waters in south and Central Sweden, was analyzed to reveal their relationships to substrate and habitat. Most species did not show any pronounced preference for any substrate, occurring in several diverse substrates, and especially in periphytic environments. Only a few species seemed to specialize in bog substrates. Some taxa were found, sometimes at a high frequency, on an artificial substrate, white cotton, indicating a high degree of mobility.     

Role of arylalkylamine <Emphasis Type="Italic">N</Emphasis>-acetyltransferase in regulation of biogenic amines levels by gonadotropins in <Emphasis Type="Italic">Drosophila</Emphasis>

The effect of 20-hydroxyecdysone (20E) and the juvenile hormone (JH) on the activity of the arylalkylamine N-acetyltransferase (AANAT) was studied in young females of wild-type D. virilis and D. melanogaster. 20E feeding of the flies led to a decrease in AANAT activity in both species when dopamine (DA) was used as substrate, but did not affect the enzyme activity when octopamine (OA) was used as substrate. JH application increased AANAT activity with DA as substrate in both species, but did not change it with OA as substrate. AANAT activity was also measured in young females of a JH-deficient strain of D. melanogaster, apterous ^56f . A decrease in the enzyme activity was observed in the mutant females as compared to wild-type. Mechanisms of regulation of DA level by gonadotropins in Drosophila are discussed.     

The cation status of some indigenous plants from a Cango valley limestone-sandstone transition,South Africa

Leaf tissue of four representative species from a limestone-sandstone transition, together with their respective soils, were analysed for cations. The species studied comprisedLeucospermum cuneiforme (Proteaceae) from the acid sandstone,Indigofera sp. nov. (Fabaceae) from the base-rich limestone,Elytropappus rhinocerotis (Asteraceae) from the transition zone andDodonaea angustifolia (Sapindaceae) which occured on all three substrates. The sandstone substrate is low in cations, particularly K and it is suggested that the Leucospermum may supplement its K nutrition with Na. Despite growing on soils of differing cation content, Dodonaea maintained a constant leaf cation content over the three substrates.     

Physiological characteristics of several rumen protozoa grown in vitro with observations on within and among species variation

When fed equal amounts of substrate, two Epidinium caudatum clone cultures of markedly different size produced similar volumes of microbial protoplasm. Addition of up to 50% volume of 72 h culture medium had no inhibitory effects on growth of Epidinium. Two clone cultures of Epidinium caudatum from Australia had longer generation times and showed less substrate attachment when compared to Ohio clones of this same species. Substitution of alfalfa for orchardgrass in the normal substrate increased Epidinium concentrations, while feeding only ground orchardgrass or alfalfa resulted in a marked decrease or disappearance of the protozoa. Eudiplodinium impalae, isolated from rumen contents of a steer in Australia, was successfully cultured, with generation times for this species averaging 11.3 h. Reducing particle size of the substrates by ball-milling was detrimental for growth of Entodinium and Epidinium; however, Eudiplodinium increased in concentration. Significant concentration differences were observed among six clone cultures of Epidinium obtained from Europe. A generation time of 18.7 h was measured for Enoploplastron triloricatum when the culture was transferred every 12 h. Lowering the incubation temperature to 34 °C completely inhibited protozoal growth of Epidinium and Entodinium exiguum after 12 days, but not for Entodinium caudatum.     

Majority of Actinomadura clinical isolates from sputa or bronchoalveolar lavage fluid in Japan belongs to the cluster of Actinomadura cremea and Actinomadura nitritigenes, and the description of Actinomadura chibensis sp. nov

In Japan during 1996-2004, 21 actinomycete strains that have madurose as the diagnostic cell-wall sugar and show true branching in their substrate and aerial mycelia were isolated from sputa or bronchoalveolar lavage (BAL) fluid of patients with pulmonary infections or who were suspected of having related infections. Chemotaxonomic studies showed that all the isolates belong to the genus Actinomadura. Among them, six and seven strains were classified respectively into clusters of Actinomadura nitritigenes and Actinomadura cremea based on 16S rDNA analyses because their 16S rDNA similarities to those respective species were greater than 99.5%. To our knowledge, this is first report that strains of above two species were isolated from clinical specimens. Neither Actinomadura madurae nor Actinomadura pelletieri strain was isolated, and one new species, Actinomadura chibensis, was proposed; the remaining seven strains were not assigned into any known species, suggesting the presence of another new Actinomadura species.     

Effect of habitat structure on positional behavior and support use in three species of lemur

This study compares locomotor and postural behavior and substrate use of three species of lemur, the diademed sifaka (Propithecus diadema edwardsi), the brown lemur (Eulemur fulvus rufus), and the red-bellied lemur (Eulemur rubriventer) at two different localities within Ranomafana National Park. The object of the study is to see if there are quantitative differences in the behavior of the lemurs or their choice of substrates in forests that have different structural attributes. Analysis of the physical characteristics of the habitat demonstrates that compared to the Talatakely area, the forest at Vatoharanana has a higher proportion of larger, taller trees. The behavior of the lemurs also differs in the two areas: all species leap less and climb and move quadrupedally more at Vatoharanana. All species use small size supports less frequently at Vatoharanana, choosing insted medium size supports (all three species) or tiny supports (Propithecus andE. fulvus) found in tree crowns and terminal branches. The lemurs prefer (i.e. use more often than would be expected based on abundance) large trees at both sites. At Vatoharanana however, they are more frequently observed higher in trees and in taller trees with greater trunk breadth. The differences in locomotor behavior are in part due to the fact that at Vatoharanana, more bouts are collected during feeding and foraging than during travel. The relationship between this difference in activity pattern and the structural differerences in the two forests, however, is not clear. This study points out the need for longer term field studies of positional behavior and substrate use that incorporate the variety of forest types the subject species inhabit.     

Competition and coexistence of rhizomatous perennial plants along a nutrient gradient

I studied competition and coexistence of three tall clonal perennial plant species, Calamagrostis epigejos (L.) Roth, Solidago canadensis L., and Tanacetum vulgare L. along a gradient of soil productivity over five years. A replacement series field experiment was conducted with high, moderate and low fertility levels in 1m×1m plots. There were significant effects of soil type on ramet density (P<0.001), mean height (P<0.01), and total biomass (P<0.01). Ramet density, mean height, and total biomass increased with increasing soil fertility. There were also significant effects of mixture on ramet density (P<0.01), but not on mean height and total biomass for all species. Significant neighbor effects on ramet density and total biomass (P<0.01) were found for Solidago, showing that it is important whether Tanacetum or Calamagrostis is its neighbor within mixtures. During the five years there was only one case of competitive exclusion: Calamagrostis excluded Solidago on the most fertile substrate in the fifth growing season. In most cases species coexisted over the five years. Each of the three species was able to dominate in at least one combination of substrate type and mixture. The experiment showed that asymmetric competition for light on substrates of high fertility, symmetric competition for nutrients on nutrient-poor soil and positive interactions especially on substrates of intermediate fertility played a role. A founder effect was evident in aggregated mixtures of Calamagrostis and Solidago on the nutrient-rich substrate. A conceptual model of the relative importance of root competition for soil nutrients, shoot competition for light, and positive interactions along the fertility gradient is presented. The model emphasizes that positive interactions play an important role over a broad range of the productivity scale with a peak at intermediate levels of fertility. On the substrate of high productivity shoot competition for light is more important than positive interactions and root competition for soil nutrients as well. The competitive superiority of Calamagrostis on the most productive substrate was evident only in the long run. Rare events like extreme summer drought or selective herbivore pressure caused a switch in dominance in mixtures with Solidago, respectively Tanacetum. The guerrilla growth strategy of Calamagrostis and interference competition through a dense cover of aboveground biomass and litter could further cause competitive exclusion.     

Comparative studies on ectomycorrhizae synthesized with various in vitro techniques using Picea abies and two Hebeloma species

Summary Various in vitro synthesis techniques with Picea abies and two Hebeloma species showed that structures of the mantle and Hartig net of synthesized ectomycorrhizae within the given two fungus species are stable. However, thickness of mantle, and penetration depth and number of hyphal cell rows between cortical cells of the Hartig net are dependent on techniques and substrates. Porous glass balls as substrate in the Erlenmeyer technique seem to suppress or delay mantle and Hartig net formation. With the other techniques (growth pouch, open cuvette, Erlenmeyer with a vermiculite-peat moss mixture) development of the mantle is simultaneous with or shortly in advance of Hartig net formation. The ectomycorrhizae of the two tested Hebeloma species are similar and cannot be morphologically differentiated by the in vitro techniques used.     

Oxidation of amines by yeasts grown on 1-aminoalkanes or putrescine as the sole source of carbon,nitrogen and energy

The maximum growth rate of Trichosporon cutaneum CBS 8111 in chemostat cultures was 0.185 h^-1 on ethylamine and 0.21 h^-1 on butylamine, that of Candida famata CBS 8109 was 0.32 h^-1 on putrescine.The amine oxidation pattern of the ascomycetous strains studied, viz. Candida famata CBS 8109, Stephanoascus ciferrii CBS 4856 and Trichosporon adeninovorans CBS 8244 was independent of the amine that had been used as the growth substrate. It resembled that of benzylamine/putrescine oxidase found in other ascomycetous yeasts. However, differences in pH optimum and substrate specificity were observed between the amine-oxidizing systems of these three species.The amine oxidation pattern of cell-free extracts of Trichosporon cutaneum CBS 8111 varied with the amine that was used as growth substrate. The enzyme system produced by Cryptococcus laurentii CBS 7140 failed to oxidize isobutylamine and benzylamine, and showed a high pH optimum.The synthesis of amine oxidase in the four yeast strains studied was not repressed by ammonium chloride and was weakly repressed by glucose but was strongly repressed if both compounds were present in the growth medium.     

Effects of substrate nitrate concentration on symbiotic nodule formation in actinorhizal plants

The response ofAlnus glutinosa, Casuarina cunninghamiana, Elaeagnus angustifolia andMyrica cerifera to a range of substrate nitrogen levels in solution, in relation to plant growth, infection, nodulation and root fine structure was studied. Nine concentrations of potassium nitrate ranging from 0.05 to 3.0 mM, were tested on each of the species. Plants were inoculated withFrankia pure cultures after a two week exposure to one of the nine levels of added nitrate. After six more weeks with constant exposure to nitrate, plants were harvested and assayed. With the exception of Myrica, regression analyses of whole plant dry weights as a function of added nitrate were highly significant. There was a tendency for nodulated plants grown at intermediate levels of added nitrate to exhibit higher relative growth rates, probably due to the additive effect of substrate nitrogen and fixation of atmospheric nitrogen. The mean numbers of nodules per plant were, with the exception of Alnus, significantly higher at intermediate levels of added nitrate, as were mean nodule dry weights. A highly significant inverse relationship between nodule weight as a percentage of whole plant weight was found in Elaeagnus and Myrica. The observed response of Elaeagnus to added nitrate compared to other actinorhizal plants appears to demonstrate that root hair infected plants are much more sensitive to the inhibitory effects of added nitrate than plants infected by intercellular penetration. A sharp reduction in the presence of root hairs at high concentrations of nitrate was observed. This indicates that the inhibition of nodulation in some actinorhizal plant species results from nitrate induced root hair suppression.     

The impact of changing irrigation practices in rice fields on frog populations of the Kanto Plain, central Japan

Rice fields are important substitute wetlands for frogs. Traditionally, rice fields in Japan were supplied with water and drained via shallow earth ditches (old-style). In the last 30 years, however, more than 80% of rice fields have been converted to a new irrigation system in which water is typically supplied through underground pipes via taps and is drained into deep, concrete-sided ditches (new-style). We compared the occurrence of frogs in paired areas of old- and new-style rice fields at six locations in Ibaraki Pref., central Japan, from May to August 1995. The Japanese tree frog (Hyla japonica) did not differ in abundance between the two types of rice fields, but the Japanese brown frog (Rana japonica) and the Tokyo daruma pond frog (Rana porosa porosa) preferred the old-style rice fields. These findings suggest that the status ofRana species has been adversely affected by the conversion of rice fields to the new irrigation system. Modification of the deep, U-shaped concrete ditches and the water management regime during the spawning season is needed to safeguard these species.