Ecology and diversity of waxcap (Hygrocybe spp.) Fungi

Summary

Members of the genus Hygrocybe are ubiquitous and colourful components of many undisturbed and nutrient-poor grasslands in the UK. Through a number of detailed surveys of the distribution of Hygrocybe spp. and of genera showing similar patterns of occurrence (e.g. Clavaria spp., Entoloma spp., Geoglossum spp.) a picture is gradually emerging of the more important ‘waxcap grassland’ sites, and of those species in greatest need of protection. Waxcap fungi are far from ideal experimental organisms which explains why so little has been published about their biology and ecology. They cannot be cultured on laboratory media and the correct conditions for inducing spores of most species to germinate have yet to be established. Nevertheless approaches such as isotope ratio mass spectrometry and the use of molecular biology techniques are beginning to provide an insight into the role played by these organisms in grassland ecosystems, and why they are so adversely affected by many agricultural practices. Current field experiments at various sites including Sourhope near Kelso will also permit investigations into waxcap ecology to be correlated with parallel studies of other members of the soil biota.     

Characterization of microsatellite markers for rough fescue species (Festuca spp.)

One major challenge in genetic diversity analysis of minor grass species is the lack of informative molecular markers. A set of 210 simple sequence repeat (SSR) markers developed from wheat and barley were evaluated for their transferability to three rough fescue species [Festuca altaica Trinius, F. campestris (Rydb.) and F. hallii (Vassey) Piper]. Twelve SSR primer pairs displayed scorable polymorphism among and within the species. The number of alleles per primer pair ranged from three to 17 with an average of 8.3 for all the species and greatly varied for each species. About 82% of SSR variation resided within the species. Festuca hallii was genetically most distinct among the three species.     

Virulence and antimicrobial resistance potential of Aeromonas spp. associated with shellfish

Aeromonas spp. are associated with seafood-related outbreaks worldwide. In seafood industry, shellfish play a major role in global seafood production. With this emerging trend of shellfish consumption, shellfish-related bacterial infections are being reported frequently. Aeromonas spp. are natural contaminants found in shellfish. Although 36 species have been identified, some species including Aeromonas hydrophila, Aeromonas caviae and Aeromonas veronii biotype sobria have dragged major attention as foodborne pathogenic bacteria. The ability to elaborate a variety of virulence factors of Aeromonas spp. contributes to the pathogenic activities. Also, emerging antimicrobial resistance in Aeromonas spp. has become a huge challenge in seafood industry. Furthermore, multidrug resistance increases the risk of consumer health. Studies have supplied pieces of evidence about the emerging health risk of Aeromonas spp. isolated from seafood. Therefore, the present review was intended to highlight the prevalence, virulence and antimicrobial resistance of Aeromonas spp. isolated from various types of shellfish.     

Isolation, characterization and mapping of simple sequence repeat markers in zoysiagrass (Zoysia spp.)

The genus Zoysia consists of 16 species that are naturally distributed on sea coasts and grasslands around the Pacific. Of these, Zoysia japonica, Zoysia matrella, and Zoysia tenuifolia are grown extensively as turfgrasses, and Z. japonica is also used as forage grass in Japan and other countries in East Asia. To develop simple sequence repeat (SSR) markers for zoysiagrass (Zoysia spp.), we used four SSR-enriched genomic libraries to isolate 1,163 unique SSR clones. All four libraries contained a high percentage of perfect clones, ranging from 67.1 to 96.0%, and compound clones occurred with higher frequencies in libraries A (28.6%) and D (11.6%). From these clones, we developed 1,044 SSR markers when we tested all 1,163 SSR primer pairs. Using all 1,044 SSR markers, we tested one screening panel consisting of eight Zoysia clones for testing PCR amplifications, from which five unrelated clones, among the eight, were used for polymorphism assessment, and found that the polymorphic information content ranged from 0 (monomorphic loci) to 0.88. Of the 1,044 SSR markers, 170 were segregated in our mapping population and we mapped 161 on existing amplified fragment length polymorphism-based linkage groups, using this mapping population. These SSR markers will provide an ideal marker system to assist with gene targeting, quantitative trait locus mapping, variety or species identification, and marker-assisted selection in Zoysia species.Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Chemosensory responses of juvenile Coho salmon, Oncorhynchus kisutch, Dolly Varden, Salvelinus malma, and sculpins (Cottus spp.) to eggs and other tissues from adult Pacific salmon

The carcasses of semelparous Pacific salmon (Oncorhynchus spp.) provide nutrients that enter aquatic ecosystems by various pathways, including direct consumption of tissue by fishes. Salmonids and other species frequently eat eggs and other tissues from dead salmon but the roles of vision and olfaction are unclear, as is the relative attraction to different tissues. Accordingly, we conducted a series of in situ experiments using minnow traps in two natural streams in Alaska to test the relative roles of chemosensory and visual cues in attraction of fishes to eggs from adult Pacific salmon, and then compared catch rates of traps baited with eggs, muscle, liver, and testis. Experiments indicated that chemical traces were necessary and sufficient to attract juvenile Dolly Varden (Salvelinus malma), coho salmon (Oncorhynchus kisutch), and sculpins (Cottus spp.) into traps. Combining both sites, 70 salmonids and 19 sculpins were trapped using visual and chemical cues, and 53 and 21, respectively, for traps with only chemical cues. Traps with only the sight of eggs caught no salmonids and only 5 sculpins, comparable to empty control traps. In addition, eggs were markedly more attractive than the other tissues, trapping 68?% of the salmonids and 69?% of the sculpins, compared to 14?% and 15?% for muscle tissue, 12?% and 11?% for liver, and 6?% and 5?% for the testis. Visual cues undoubtedly play a role in egg consumption in streams, but these experiments indicated a very important role of chemical traces in attracting fish to the vicinity of the eggs, and selective attraction of eggs over other salmon tissues.     

Structure of herbivore communities in two oak (Quercus spp.) hybrid zones

Summary We examined patterns of density and species diversity for leaf-mining Lepidopterans and gall-forming Hymenopterans in two oak (Quercus spp.) hybrid zones: Quercus depressipes x Q. rugosa and Q. emoryi x Q. coccolobifolia. In both species complexes, hybrid hosts typically supported significantly lower densities and species diversity of parasites than did parental types. This contradicts the findings of Whitham (1989) that suggested that hybrid hosts may act as parasite sinks both in ecological and evolutionary time. We discuss features of hybrid zones that are likely to influence patterns of herbivory.     

Allantus luctifer (Hymenoptera: Tenthredinidae), a candidate agent for the biological control of Rumex spp.

The dock plant (Rumex spp.) is one of the most problematic pasture weeds worldwide. Allantus luctifer was selected as a potential biological control agent for Rumex spp. Continuous rearing of A. luctifer was carried out from 2005 to 2006, and its general biology is presented in this report. The preliminary host specificity test showed a promising result for using A. luctifer to control Rumex spp.     

Liver iron overloading in captive muriquis (Brachyteles spp.)

Background Iron accumulation was investigated qualitatively and quantitatively in the liver of 15 captive Brachyteles spp. Methods Hepatic hemosiderosis index (HHI) was determined as the area percentage of the liver parenchyma occupied by hemosiderin and ferritin deposits, through computerized histomorphometric analysis of Prussian blue–stained histologic sections. Results All studied animals presented liver hemosiderosis, and HHI ranged from 0.2% to 41.7%. There were no significant differences in HHI between muriqui species or genders, and no correlations were detected among HHI and age, time in captivity or body mass. Iron deposits were accompanied by other hepatic disorders. Conclusions This is the first study addressing the occurrence and consequences of iron overloading in the liver of muriquis. We propose that hemosiderosis may act as a contribute factor for the development of hepatic injuries. Further studies are advised to clarify the role of diet in the pathogenesis of hemosiderosis in these atelids.     

Chaff piles of harvester ant (Messor spp.) nests in a desert ecosystem

Summary The plant species composition of the chaff piles of three species of harvester ant (Messor spp.) and the contribution of the chaff to the organic pool were studied from August 1985 to July 1987. There were distinct differences in the plant species composition of the chaff of the three species. We attribute this to the different diets of the three species, which reflect the relative sizes of their individuals and their foraging strategies. The amount of chaff accumulated varies greatly between the three species (Messor rugossus: 127–196 g · ha^–1 · y^–1;Messor ebeninus: 2823–4437 g · ha^–1 · y^–1;Messor arenarius: 2165–2535 g · ha^–1 · y^–1), although the number of nests per hectare is virtually the same. We found that the amount of chaff is related to the rate of activity and the size of the individuals of each of the three ant species. The total chaff accumulated during the study period was 19.2 kg · ha^–1, which is an important contribution to the organic matter in the soil in the Negev desert ecosystem.     

Evaluation of Streptomyces spp. and Bacillus spp. for biocontrol of Fusarium wilt in chickpea (Cicer arietinum L.)

A study was carried out to test direct and indirect antagonistic effect against Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceri (FOC), and plant growth-promoting (PGP) traits of bacteria isolated from rhizosphere soils of chickpea (Cicer arietinum L.). A total of 40 bacterial isolates were tested for their antagonistic activity against FOC and of which 10 were found to have strong antagonistic potential. These were found to be Streptomyces spp. (five isolates) and Bacillus spp. (five isolates) in the morphological and biochemical characterisation and 16S rDNA analysis. Under both greenhouse and wilt sick field conditions, the selected Streptomyces and Bacillus isolates reduced disease incidence and delayed expression of symptoms of disease, over the non-inoculated control. The PGP ability of the isolates such as nodule number, nodule weight, shoot weight, root weight, grain yield and stover yield were also demonstrated under greenhouse and field conditions over the non-inoculated control. Among the ten isolates, Streptomyces sp. AC-19 and Bacillus sp. BS-20 were found to have more potential for biocontrol of FOC and PGP in chickpea. This investigation indicates that the selected Streptomyces and Bacillus isolates have the potential to control Fusarium wilt disease and to promote plant growth in chickpea.     

The diet of Weddell seals in McMurdo Sound, Antarctica as determined from scat collections and stable isotope analysis

The diet of adult and juvenile Weddell seals (Leptonychotes weddellii) in McMurdo Sound, Antarctica, was determined from both scat and stable isotope analyses, to ascertain if foraging behavior varied with age, season, or diving pattern. Scats were collected over 6 years and recovered hard parts identified. Stable carbon and nitrogen isotope values were determined for seal blood samples and potential prey items and used to identify primary prey species and assess trophic interactions. Pleuragramma antarcticum remains were recovered from between 70 and 100% of the scats, and there was little evidence for inter-annual or age-specific variation in foraging behavior. However, stable isotope and dive data analyses indicated that while most seals foraged predominantly on pelagic fish and squid, some juveniles concentrated on shallow benthic Trematomus spp. Combining these three methods permitted firm conclusions about diet and foraging behavior to be drawn. Received: 10 June 1997 / Accepted: 8 November 1997     

Latitudinal gradients in the species richness of Australian termites (Isoptera)

Abstract Using data on the geographic range of 260 described species in the Atlas of Australian Termites, seven ‘regions’ with more complete data, across a wide range of latitudes were selected for further analysis. For these regions, mean species richness (± SE) was calculated for (i) all species from all families, (ii) Termitidae (197 spp.), (iii) Amitermes spp. (Termitidae, 58 spp.), (iv) all families excluding Amitermes spp. (139 spp.), (v) Termopsidae (5 spp.), (vi) Kalotermitidae (32 spp.) and (vii) Rhinotermitidae (25 spp.). In addition, we compared the Atlas data with species richness for five regions, across a comparable range of latitudes, based on the pooled species richness of described and un-described species given in community studies. No group of termites showed a consistent decline in species richness from tropical to temperate latitudes for either data set. The Atlas data showed similar total species richness from the tropics to the mediterranean southwest, before declining to lowest species richness at the highest latitudes. Species richness of Amitermes spp. and Rhinotermitidae was highest in the southwest. Termopsidae and Kalotermitidae showed no latitudinal pattern in species richness. Community studies showed highest and lowest total species richness in the southwest and at the highest latitudes (south-coastal Western Australia), respectively, and similar species richness from the tropics to arid central Australia. Species richness of. Amitermes spp. was highest in the southwest (31 spp.). Kalotermitidae and Rhinotermitidae showed no clear latitudinal pattern. The latitudinal patterns of species richness for the Australian termites is consistent with that for the Australian vertebrates and ants in that they differ from patterns established for these taxa on other continents.     

Distribution and Seasonal Abundance of Trematode Parasites (Trematoda: Allocreadiidae: <Emphasis Type="Italic">Crepidostomum</Emphasis> spp.) in burrowing-mayfly nymphs (Ephemeroptera: Ephemeridae: <Emphasis Type="Italic">Hexagenia</Emphasis> spp.) from Connecting Rivers of the Laurentian Great Lakes

Burrowing-mayfly nymphs such as Hexagenia spp. have been used extensively in North America and Europe as a biomonitoring tool to indicate mesotrophic water quality, yet infestation by associated parasites has not been well documented. We performed laboratory analysis of archived samples of Hexagenia spp. nymphs collected in 1985 and 1986 to provide base-line data on the distribution (1985) and seasonal infestation (1986) of the trematode parasite Crepidostomum spp. in Hexagenia spp. nymphs in connecting rivers between Lakes Superior and Erie of the Laurentian Great Lakes. In May and June 1985, frequency of occurrence of metacercariae was widely distributed throughout the connecting rivers (63% of 203 stations with nymphs), except in areas where nymph densities were relatively low (i.e.,≤69 nymphs/m²). Distribution was probably underestimated in the present study because of low probability (mean = 31%, range = 0–57%) of detecting infestation in a small number of collected nymphs ( ≤10) at nymph densities ≤69/m². In 1986, seasonal infestation between April and October occurred in 3.3% (627) of 18696 nymphs. Overall prevalence, mean intensity, and mean abundance of parasites at one station in the St. Marys River indicate parasite transmission occurred between June and September. This period of transmission is dependent on the life-cycle of the parasite. In addition, the life-cycle of Hexagenia spp. determines which annual cohort of nymphs is infested and therefore, the duration of infestation. Although, no impacts of infestation on Hexagenia spp. nymphs were observed in the present study, infestation intensities were high enough (≥25 metacercariae per nymph) at one station in the St. Marys River to potentially cause tissue damage in a high proportion (53%) of infested nymphs.     

Biology and host range of Ophiomyia camarae Spencer (Diptera: Agromyzidae), a potential biocontrol agent for Lantana spp. (Verbenaceae) in Australia

The life history and host range of the herringbone leaf-mining fly Ophiomyia camarae, a potential biological control agent for Lantana spp., were investigated. Eggs were deposited singly on the underside of leaves. Although several eggs can be laid on a single leaf and a maximum of three individual mines were seen on a single leaf, only one pupa per leaf ever developed. The generation time (egg to adult) was about 38 days. Females (mean 14 days) lived longer than males (mean 9 days) and produced about 61 mines. Oviposition and larval development occurred on all five lantana phenotypes tested. Eleven plant species representing six families were tested to determine the host range. Oviposition and larval development occurred on only lantana and another nonnative plant Lippia alba (Verbenaceae), with both species supporting populations over several generations. A CLIMEX model showed that most of the coastal areas of eastern Australia south to 30°16′ S (Coffs Harbour) would be suitable for O. camarae. O. camarae was approved for release in Australia in October 2007 and mines have been observed on plants at numerous field sites along the coast following releases.     

Bio-deposition of Amorphous Silica by an Extremely Thermophilic Bacterium,Thermus spp.

The bio-deposition of amorphous silica, which occurred in vitro by exposure to the extremely thermophilic bacterium Thermus spp. began from the latter part of the exponential phase of growth of the bacteria. The concentration with which the deposition occurred exceeded the solubility of amorphous silica of neutral pH at the temperature 60~85°C. Our observations suggest that Thermus spp. promotes the formation of siliceous minerals in a geothermal environment.     

The action of post-dispersal beetles (Coleoptera: Scarabaeidae) and ants (Hymenoptera: Formicidae) on scats of Didelphis spp. (Mammalia: Didelphidae)

A two year study of dung beetles and ants acting on scats of two species of opossum (Didelphis spp.) was carried out. Scats were left in the field in order to detect post-dispersal agents. A portion of each scat (30 %) was examined for seeds in the laboratory. Beetles were recovered from burrows (51% of 84 faecal samples left in the field) where they either buried scats of opossums or were attracted, together with ants, to pitfalls (N = 10) baited with opossum scats. Dung beetles were the main post-dispersal agents of seeds found in scats of opossums, rolling the scats away or burying then on the site of deposition. They buried faeces at 4 to 15 cm in depth (N = 22 tunnels). The main dung beetles identified (medium to large size) were Eurysternus (28.7 % in pitfalls) and Dichotomius (13.7 %), Coprophanaeus (seen only directly on faeces), besides small-bodied beetles (< 10 mm; 57.6 %). The ant Acromirmex sp. transported some seeds from scats. This species was present in 25.5 % of all Formicidae samples (pitfall). These post-dispersal agents contribute to avert scat seed predators such as rodents, and to accelerate seed bank formation.     

Resistenz verschiedener Kultur- und Wildtomatenpflanzen (Lycopersicon spp.) gegenüber Botrytis cinerea Pers.

Resistance of different cultivated and wild tomato plants (Lycopersicon spp.) to Botrytis cinerea Pers. 20 provenances of different cultivated and wild tomato plants (Lycopersicon spp.) were screened for resistance to Botrytis cinerea Pers. using an in vitro-leaf necrosis test. The Botrytis resistance decreased with increasing age of the leaves corresponding to their insertion height (relative youth resistance respectively senescence susceptibility). The 6 B. cinerea-isolates used for inoculation differed significantly in virulence. With increasing inoculum age a virulence reduction of the various B. cinerea-isolates occurred. Within the investigated test plant collection 2 wild species –L. columbianum and L. hirsutum– proved to be resistant in each stage of development to all B. cinerea-isolates and additionally showed field resistance.     

Occurrence,antibiotic resistance and enteroxigenicity of Staphylococcus spp. in tonsils of slaughtered pigs in Greece

The aims of the present study were to examine the occurrence of Staphylococcus spp. in the tonsils of slaughtered pigs in a regional slaughterhouse in Greece, the antibiotic resistance of the Staphylococcus spp. isolates, and the enteroxigenicity of the S. aureus isolates. Staphylococcus spp. were isolated in 70 (48·61%) out of the total 144 tonsil samples. The predominant species was S. aureus in coagulase-positive staphylococci (CoPS), while the predominant species were Staphylococcus epidermidis and Staphylococcus saprophyticus in the coagulase-negative staphylococci (CoNS). Staphylococcus spp. isolates presented high antibiotic resistance frequencies to tetracycline (97·1%) or clindamycin (80·0%) and low antibiotic resistance frequencies to fusidic acid (14·3%). No methicillin-resistant S. aureus (MRSA) strains were identified, and all Staphylococcus spp. isolates were susceptible to vancomycin. Among the 26 S. aureus isolates, 21 (80·76%) possessed staphylococcal enterotoxin genes with seven different enterotoxin gene profiles. The predominant enterotoxin profile was seg, sei and sej with seven S. aureus isolates. The occurrence of multidrug resistant Staphylococcus spp. in pig tonsils indicate public health risk to pork consumers and handlers in developing antimicrobial resistance.     

Characterisation of the double genome structure of modern sugarcane cultivars (Saccharum spp.) by molecular cytogenetics

Cultivated sugarcane clones (Saccharum spp., 2n=100 to 130) are derived from complex interspecific hybridizations between the speciesS. officinarum andS. spontaneum. Using comparative genomic DNA in situ hybridization, we demonstrated that it is possible to distinguish the chromosomes contributed by these two species in an interspecific F1 hybrid and a cultivated clone, R570. In the interspecific F1 studied, we observed n+n transmission of the parental chromosomes instead of the peculiar 2n+n transmission usually described in such crosses. Among the chromosomes of cultivar R570 (2n=107–115) about 10% were identified as originating fromS. spontaneum and about 10% were identified as recombinant chromosomes between the two speciesS. officinarum andS. spontaneum. This demonstrated for the first time the occurrence of recombination between the chromosomes of these two species. The rDNA sites were located by in situ hybridization in these two species and the cultivar R570. This supported different basic chromosome numbers and chromosome structural differences between the two species and provided a first bridge between physical and genetical mapping in sugarcane.