Slow and steady wins the race: contrasted phylogeographic signatures in two Alpine amphibians

A deeper phylogeographic structure is expected for slow-dispersing habitat specialists compared to widespread adaptable species, especially in topographically complex regions. We tested this classic assumption by comparing the genomic (RAD-sequencing) phylogeographies of 2 amphibians inhabiting the Swiss Alps: the mobile, cosmopolitan common frog (Rana temporaria) against the stationary, mountain endemic Alpine salamander (Salamandra atra). Our results ran opposite of predictions: the frog displayed significantly higher genetic divergences and lower within-population variation compared to the salamander. This implies a prominent role for their distinctive glacial histories in shaping intraspecific diversity and structure: diversification and recolonization from several circum-Alpine micro-refugia for the frog versus a single refugium for the salamander, potentially combined with better population connectivity and stability. These striking differences emphasize the great variability of phylogeographic responses to the Quaternary glaciations, hence the complexity to predict general patterns of genetic diversity at the regional scale, and the forces that underlie them.     

Factors affecting the breeding success of the African Black Oystercatcher (Haematopus moquini): a perspective on protection and food availability

Breeding success (fledglings pair^?1 y^?1) of the Red-listed African Black Oystercatcher (Haematopus moquini) is highly variable, both spatially and temporally. Despite a diversity of natural factors causing this variability, there is evidence that two anthropogenic factors, i.e. disturbance and an introduced mussel (Mytilus galloprovincialis), are having an impact on the local breeding success of this species. Using a data set comprising 87 site-years of nest-monitoring data across most of the species’ breeding range, we analysed the extent and causes of variability in breeding success. Breeding success differed across three population categories defined by varying levels of human disturbance: island populations, protected mainland populations, and unprotected mainland populations. Differences in breeding success between island populations and protected mainland populations were likely due to differing exposure to predators; however, differences between protected and unprotected mainland populations were unlikely caused by this as both experience equivalent predation levels (although from different predators). Protection only improved the breeding success of oystercatchers in very high-quality habitats (with a high biomass of alien mussels), and where populations were ‘released’ from high levels of human disturbance. In unprotected mainland areas, human activity impacted on the breeding success of local populations primarily through predation of small chicks by uncontrolled dogs, and by rising tides drowning chicks that were hiding from human disturbance. The findings of this study note the potential conservation dilemma resulting from an invasive species improving the conservation status of a Red-listed species, and encourage the implementation of restricted sites in high-quality habitats with high breeding pair densities.     

Feeding ecology of three inshore fish species at Marion Island (Southern Ocean)

The diets, morphological features and habitats of 258 specimens of the three inshore fish species Notothenia coriiceps, N. macrocephala and Harpagifer georgianus from Marion Island are described and compared. Correspondence analysis of the three diets shows the existence of three clearly defined feeding niches despite the occurrence of some common prey species. Inter-and intraspecific similarities and differences in the diets of small and large size classes of each species are also displayed by correspondence analysis. Size-limited predation by N. coriiceps of the limpet Nacella delesserti is described. Differences in the habitats occupied by the fish appear to be important in determining the species composition of their diets.     

Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs

Objective

To explore the diversity among isolates of the Actinobacillus pleuropneumoniae serovars most common in Australia (serovars 1, 5, 7 and 15) and to examine the Apx toxin profiles in selected representative isolates.

Design

A total of 250 isolates selected from different farms were examined for their genotypic profiles and a subset of 122 isolates for their toxin profiles.

Methods

The isolates of serovars 1, 5, 7 and 15 selected for this study came from different farms and different Australian states and were submitted for serotyping to the reference laboratory. The overall diversity of the strains was explored with the enterobacterial repetitive intergenic consensus (ERIC) PCR and the presence of the toxin genes was investigated with a toxin PCR assay.

Results

Some degree of variation was observed in the ERIC‐PCR pattern within all four serovars, ranging from 38% to 61% genetic diversity. When looking at the toxin gene profile and, therefore, the predicted ability to produce the expected toxin pattern, one isolate each of serovars 1 (n = 20) and 7 (n = 47) and 17 isolates of serovar 15 (n = 40) showed variation to the expected gene profile.

Conclusion

The variations in toxin gene patterns, as detected by PCR, found in this study could be related to significant changes in the gene sequence or total absence of the gene. Variation in toxin gene sequences has been observed in other countries. This variation in the toxin profile could also explain possible variation in pathogenicity observed in the field.     

Temperature-induced plasticity at cellular and organismal levels in the lizard Anolis carolinensis

Among ectotherms, individuals raised in cooler temperatures often have larger body size and/or larger cell size. The current study tested whether geographic variation in cell size and plasticity for cell size exist in a terrestrial, ectothermic vertebrate, Anolis carolinensis Voigt, 1832. We demonstrated temperature-induced plasticity in erythrocytes and epithelial cells of hatchlings lizards derived from the eggs of females sampled from four populations and incubated at multiple temperatures. Larger cells were produced in hatchlings from cooler treatments; however, hatchling body size was unaffected by temperature. Therefore, temperature-induced plasticity applies at the cellular, but not organismal, level in A. carolinensis. In addition, reaction norms for cell size differed among populations. There was a latitudinal trend in cell size and in plasticity of cell size among our study populations. The two southernmost populations showed plasticity in cell size, whereas the two northernmost ones did not. We suggest that selection pressure for larger cell size in northern, cooler environments has restricted plasticity in A. carolinensis applied at the cellular level in response to variable incubation environments.     

Genetic diversity within two Tunisian wild jirds: Meriones shawi and Meriones libycus (Rodentia,Gerbillinae)

Three Meriones species inhabit Tunisia, namely M. shawi, M. libycus and M. crassus, but little genetic data exist on these gerbils. We collected Meriones from eight localities in Tunisia, and obtained mitochondrial (cytochrome b) and nuclear (IRBP) gene sequence data for 37 and 13 specimens, respectively, belonging to two species: M. shawi and M. libycus. We also optimised three microsatellite markers previously described in M. unguiculatus to obtain a finer analysis of their genetic diversity and geographic structure, given their wide distribution. Phylogenetic inferences of cyt b and IRBP data for these species, in the context of other gerbillin data, corroborate their taxonomic affinities reported by previous studies. High cyt b haplotype diversity was observed in both species (25 haplotypes in 29 and 27 sequences for M. shawi and M. libycus, respectively) with little geographical structure for M. shawi but three divergent groups in M. libycus. The average microsatellite diversity within each population was high (H_O ≥ 0.6, H_E ≥ 0.8) with M. libycus populations attaining the highest values. Population differentiation was moderate for several population pairs (F_st ≥ 0.1), the highest being between M. shawi populations. However, genetic distance among populations was not significantly correlated with geographic distance in either M. shawi or M. libycus. Our results contribute to a better characterisation of Tunisian Meriones species, suggesting high geographic structure in mtDNA of M. libycus populations within North Africa.     

Hypomagnesaemia in cattle

Leptospirosis is an important animal and human health problem in New Zealand, and the epidemiological and ecological aspects of infection in domestic species and free-living species are described. The characteristics of infection with a particular serovar are often considerably different in different species of animal and primary epidemiological investigations involve differentiating between maintenance-host populations and accidental-host populations for the serovars present in a particular ecosystem.

Cattle and pigs are maintenance hosts for hardjo and pomona respectively. Balcanica is maintained by possums (Trichosurus vulpecula) and ballum is maintained by the house mouse (Mus musculus), ship rat (Rattus rattus) and hedgehog (Erinaceus europaeus). In some regions, foci of copenhageni infection are maintained by Norway rats (Rattus norvegicus). Each serovar shows a high degree of parasitic adaption to its maintenance-host species and this is reflected in the nidality of leptospirosis in intensive farming environments. Accidental infections in domestic animals and man are the consequence of ecological associations with maintenance-host populations for particular serovars.

Control of leptospirosis in domestic animals depends on decreasing the prevalence of infection with serovars maintained within populations of domestic animals, and decreasing the degree of ecological association with free-living maintenance-host populations. Vaccination of cattle against hardjo. will considerably reduce the prevalence of infection in vaccinated herds and therefore decrease the prevalence of accidental hardjo infections in man.     

Molecular identification of polydorid polychaetes (Annelida: Spionidae): is there a quick way to identify pest and alien species?

The early detection and correct identification of polydorid polychaete species is essential as they are often encountered as invasive alien pests in aquaculture facilities or the intertidal where they may modify the ecosystem. Accurate identification is, however, often hampered by high levels of morphological similarity among species. This taxon will therefore benefit from the development of a library of sequences, such as COI barcodes, to aid identification. However, the universal primers for the cytochrome c oxidase I (COI) DNA barcoding marker has failed to consistently amplify this gene for polydorids, greatly hampering the development of such a library. We describe the development of unique PCR primers for the COI gene that work across four genera and nine species of polydorids. We also compared its efficacy with sequence data for mitochondrial cytochrome b and nuclear 18S rRNA, and a concatenated dataset consisting of all three markers. The nuclear 18S rRNA gene showed the least variation both intra- (0.0–1.2%) and interspecifically (0.6–4.3%), and was the most accurate for species identifications among the three markers. Although COI was characterised by higher intraspecific variation compared with Cyt b (0.0–14.5% and 0.0–4.2%, respectively), Cyt b showed considerably higher levels of interspecific variation (16.6–30.2%) compared with COI (2.2–20.7%). Of the two mitochondrial DNA markers, COI was actually less accurate for species identifications, having suggested two species within Boccardia pseudonatrix that was not supported by the other markers. Overall, the concatenated dataset yielded the most consistent intraspecific groupings, suggesting that this is the most accurate means of identifying polydorids using DNA sequence data. Thus, there may not be a quick and easy way to identify these species accurately using only molecular data.     

Skull size and shape variation in Psammomys spp. (Rodentia,Gerbillinae) from Tunisia,with emphasis on the impact of allometric variation on species recognition

In Tunisia both Psammomys obesus and P. vexillaris are found. These taxa have been the subject of taxonomic controversy for some time, due to variability in the classical morphological characters used for taxonomic recognition. In this study we investigated skull size and shape variation in the genus Psammomys by using geometric morphometrics to evaluate the extent of intra- and interspecific shape variation and explicitly tested for the impact of allometric shape variation on species discrimination. Eleven populations of the two species from 10 localities in Tunisia were studied. Statistical analyses of size and shape showed large size variation within P. obesus, but no shape differences were revealed among populations of this species. Interspecific analysis revealed that P. vexillaris had the smallest skull. Principal component analysis and Procrustes distances showed good discrimination between the two species after removal of the allometric component of shape variation. The results obtained show that allometric-related shape variation could mask discrimination between the two Psammomys species. This finding might explain the uncertainty in classification of these species in the past. The interspecific allometric-free phenotypic differences observed may be associated with adaptive processes linked to the different environmental and trophic preferences of the two species.     

Preliminary molecular analysis of Clostridium difficile isolates from healthy horses in northern Italy

Clostridium difficile, associated with a wide spectrum of diseases in humans, as well as in several animal species, is an important cause of colitis in adult horses and foals. The aim of this study was to investigate by toxin gene profile and PCR-ribotyping the molecular characteristics of 14 C. difficile strains isolated from 42 faeces of healthy horses. Both toxin genes, tcdA and tcdB, were present in only 1 isolate (7.1%). Six isolates (42.9%) demonstrated tcdA−/tcdB+ genotype, and seven isolates (50.0%) were tcdA−/tcdB−. All strains were binary toxin genes negative (cdtA−/cdtB−). The PCR-positive strains, except for the tcdA+/tcdB+ isolate, tested negative for, in vitro, A and/or B toxins production by EIA. Eleven distinct ribotypes were observed.In conclusion, C. difficile can be present in the normal intestinal flora of healthy adult horses, in addition to foals. These animals could therefore play an important role as potential reservoirs of toxigenic strains.     

Fusarium crookwellense-produced zearalenone in maize stubble in the field

Waste grain and vegetative material (stems and leaves) collected from a maize field several months after harvest was analysed by bi-dimensional thin layer chromatography for the presence of aflatoxins, deoxynivalenol, ochratoxin A, sterigmatocystin, T-2 toxin and zearalenone. Deoxinivalenol (0.7 mg/kg) and T-2 toxin (4.1 mg/kg) were found in the grain and zearalenone (3.0 mg/ kg) was found in the stem and leaf. No other toxins were detected. The stubble was examined for the presence of potentially toxigenic Fusarium species, and F. poae, F. moniliforme var. subglutinans and F. crookwellense were isolated and identified. When these isolates were cultured on cracked corn, only F. crookwellense was found to produce micotoxins and then only zearalenone was detected. As corn stubble is commonly grazed in Argentina and in other countries, these findings identify a further source of mycotoxins that may adversely affect animal health and productivity.     

Role of Low-Molecular-Weight Ciliostatic Toxins in Vibriosis of Bivalve Mollusks

Abstract

Toxins play a major role in bacillary necrosis of hatchery-reared bivalve larvae. Two principal types of toxin of Vibrio spp. have been identified: A proteinase (molecular weight = 40,000) that degrades connective tissue and at least one ciliostatic toxin (molecular weight = 500–1,000). The ciliostatic toxin is stable at 100°C for 10 min and probably accounts for the cessation of feeding and swimming in the early stages of bacillary necrosis. Ciliostatic toxins were produced by 17 of 20 Vibrio spp. that are pathogenic to fish or that were isolated from diseased mollusks and included Vibrio tubiashii, V. anguillarum, and V. alginolyticus. Of 53 Vibrio and Aeromonas isolates not associated with bivalve infections, only 15 produced a ciliostatic toxin.     

Prevalence of genes for enterotoxins,toxic shock syndrome toxin 1 and exfoliative toxin among clinical isolates of Staphylococcus pseudintermedius from canine origin

A total of 74 Staphylococcus pseudintermedius strains were isolated from the 99 clinical cases of canine pyoderma or chronic otitis in our veterinary teaching hospital during May 2006–February 2008. In this study, we examined the genetic distribution of staphylococcal pyogenic toxins such as staphylococcal enterotoxins A (sea), B (seb), C (sec), D (sed), E (see), and toxic shock syndrome toxin 1 (tst) as well as the previously characterized S. intermedius exfoliative toxin (siet) among those isolates. The polymerase chain reaction analyses with the toxin gene‐specific primers revealed that 18 (24.3%) of 74 S. pseudintermedius isolates carried the sec genes, but none of the sea, seb, sed, see and tst genes. Further DNA sequencing analysis of the amplified sec genes revealed that they all belonged to the canine type C staphylococcal enterotoxin (SEC_canine) whose superantigenic activity has been demonstrated. In addition to the sec_canine genes, our polymerase chain reaction results showed that all the 74 isolates carried the siet gene. Since both SEC_canine and SIET toxins are known to be biologically active, it would be interesting to investigate how those toxins are involved in the pathogenesis of the canine diseases by S. pseudintermedius such as pyoderma or chronic otitis.     

The prevalence of Proctoeces (Trematoda: Fellodistomidae) metacercarial infections in the brown mussel Perna perna (Bivalvia: Mytilidae) around the southern African coast

Unencysted trematode metacercariae of the genus Proctoeces were found embedded in the mantle tissue and visceral mass of the intertidal mussel Pema pema. Data on the prevalence and intensity of infection in southern African populations of Pema are presented. Results from a geographic survey indicated that Proctoeces infections were more prevalent in the region Port Elizabeth to Isilaka. At the majority of sites both prevalence and intensity of infection increased in conjunction with host size. Detailed studies of mussels from Dwesa failed to show seasonal changes in metacercarial infection. A strong relationship, however, was found between sex of host and parasitic infection, with female mussels harbouring the most metacercariae. The most heavily infected mussels examined came, ironically, from two nature reserves situated on a stretch of coastline where otherwise unprotected mussel stocks are subjected to intense exploitation by man. The possible pathogenic effects of Proctoeces on such highly stressed mussel populations clearly merits further attention.     

Phylogenetic relationship and variation of alarm call traits of populations of red‐cheeked ground squirrels (Spermophilus erythrogenys sensu lato) suggest taxonomic delineation

Distribution area and taxonomic borders within the species complex Spermophilus erythrogenys sensu lato remain questionable. Early evidence suggests that red‐cheeked ground squirrels of Southeast Kazakhstan are remarkably different in terms of the acoustic structure of their alarm calls from the red‐cheeked ground squirrels of the Kurgan region in Russia. In this study, we analyzed the differences in the acoustic structure of the alarm call and mitochondrial DNA (complete control region, 1005–1006 bp and complete cytochrome b gene, 1140 bp) in 3 populations of red‐cheeked ground squirrels (Tara, Altyn‐Emel and Balkhash), all located within areas isolated by geographical barriers in Southeast Kazakhstan. We found that the alarm call variables were similar between the 3 study populations and differed by the maximum fundamental frequency (8.46 ± 0.75 kHz) from the values (5.62 ± 0.06 kHz) reported for the red‐cheeked ground squirrels from the Kurgan region of Russia. Variation in mtDNA control region was only 3% and variation in cytochrome b gene was only 2.5%. Phylogenetic trees based on cytochrome b gene polymorphism of 44 individuals from the study area and adjacent territories indicated 3 clades with high (98–100%) bootstrap support: “intermedius,” “brevicauda” and “iliensis”). We conclude that the 3 study populations in Southeast Kazakhstan belong to the clade intermedius and suggest a taxonomical revision of the species complex Spermophilus erythrogenys sensu lato, including analyses of nuclear DNA and alarm calls for populations of the brevicauda and iliensis clades.     

Prevalence of the Bacterium Coxiella burnetii in Wild Rodents from a Canadian Natural Environment Park

Zoonotic diseases impact both wild and domestic animal populations and can be transmitted to humans through close contact with animal species. Reservoir species acting as vectors are major traffickers of disease. Rodents contribute to the transmission of Coxiella burnetii although little is known about its prevalence in wild animal populations. DNA was extracted from genital swabs collected from woodland jumping mice, deer mice, Southern red‐backed voles, Eastern chipmunks, North American red squirrels, as well as Southern and Northern flying squirrels collected from Algonquin Park, Canada. The presence of C. burnetii was determined through real‐time PCR. All species sampled had some prevalence of infection, except Eastern chipmunks, indicating wild rodents in Algonquin Park are reservoirs for C. burnetii. Emerging zoonotic diseases are linked to increasing globalization. Contact amongst individuals increases as crowding, habitat loss and fragmentation increase within wild spaces. Parks often act as a last refuge for wildlife but may also be an important transmission zone of wildlife disease to humans. Investigations that attempt to discover wild reservoir species of zoonotic disease are critically important to understanding the risk of pathogen exchange between wild and human populations.     

Habitat evaluation for outbreak of Yangtze voles (Microtus fortis) and management implications

Rodent pests severely damage agricultural crops. Outbreak risk models of rodent pests often do not include sufficient information regarding geographic variation. Habitat plays an important role in rodent–pest outbreak risk, and more information about the relationship between habitat and crop protection is urgently needed. The goal of the present study was to provide an outbreak risk map for the Dongting Lake region and to understand the relationship between rodent–pest outbreak variation and habitat distribution. The main rodent pests in the Dongting Lake region are Yangtze voles (Microtus fortis). These pests cause massive damage in outbreak years, most notably in 2007. Habitat evaluation and ecological details were obtained by analyzing the correlation between habitat suitability and outbreak risk, as indicated by population density and historical events. For the source‐sink population, 96.18% of Yangtze vole disaster regions were covered by a 10‐km buffer zone of suitable habitat in 2007. Historical outbreak frequency and peak population density were significantly correlated with the proportion of land covered by suitable habitat (r = 0.68, P = 0.04 and r = 0.76, P = 0.03, respectively). The Yangtze vole population tends to migrate approximately 10 km in outbreak years. Here, we propose a practical method for habitat evaluation that can be used to create integrated pest management plans for rodent pests when combined with basic information on the biology, ecology and behavior of the target species.     

Predicted Redistribution of Ceratomyxa shasta Genotypes with Salmonid Passage in the Deschutes River,Oregon

Abstract

A series of dams on the Deschutes River, Oregon, act as migration barriers that segregate the river system into upper and lower basins. Proposed fish passage between basins would reunite populations of native potamodromous fish and allow anadromous fish of Deschutes River origin access to the upper basin. We assessed the potential redistribution of host-species-specific genotypes (O, I, II, III) of the myxozoan parasite Ceratomyxa shasta that could occur with fish passage and examined the influence of nonnative fish on genotype composition. To determine the present distribution of the parasite genotypes, we exposed eight salmonid species—three native and five stocked for sport fishing—in present and predicted anadromous salmonid habitats. We monitored fish for infection by C. shasta and sequenced a section of the parasite ribosomal DNA gene from fish and water samples to determine parasite genotype. Genotype O was present in both upper and lower basins and detected only in steelhead Oncorhynchus mykiss. Genotype I was spatially limited to the lower basin, isolated predominately from Chinook salmon O. tshawytscha, and lethal for this species only. Genotype II was detected in both basins and in multiple species, but only as a minor component of the infection. Genotype III was also present in both basins, had a wide host range, and caused mortality in native steelhead and multiple nonnative species. Atlantic salmon Salmo salar and kokanee O. nerka were the least susceptible to infection by any genotype of C. shasta. Our findings confirmed the host-specific patterns of C. shasta infections and indicated that passage of Chinook salmon would probably spread genotype I into the upper Deschutes River basin, but with little risk to native salmonid populations.

Received April 20, 2012; accepted July 19, 2012     

Significance of β2‐Toxigenic Clostridium perfringens Infections in Animals and Their Predisposing Factors – A Review

The novel β2‐toxin of Clostridium perfringens has recently been described as the cause of enteric diseases in animals. The biological activity of β2‐toxin is similar to that of the β1‐toxin with a possibly weaker cytotoxic activity. However, the production of β2‐toxin in vitro is not seen in all β2‐toxin‐gene (cpb2)‐positive C. perfringens strains, and to deduce a clinical importance solely from the detection of cpb2 is difficult. Detection of cpb2‐positive C. perfringens from various animal species with and without enteric diseases demonstrates the wide distribution of cpb2 in nature, and the presence of cpb2 gene is therefore not considered a risk by itself. Predisposing factors like low trypsin activity in the intestinal tract, antibiotic and/or antiphlogistic treatment or changes in diet can result in the selection of β2‐toxigenic C. perfringens which may lead to enteritis or enterotoxaemia.     

The occurrence of Clostridium botulinum at aquatic sites in and around Auckland and other urban areas of the North Island

Samples of bottom muds from lakes and waterways in the Auckland area were inoculated into bottles of cooked meat medium. After incubation, the media were tested for reduction of Clostridium botulinum toxin which was detected with samples from 11 of the 20 sites examined. Although toxins produced from all positive samples were neutralized by specific antisera to both type C and D toxins, it is likely that C. botulinum type Cα is the only type present in the Auckland area. All samples from other urban areas of the North Island gave negative results.