Molecular and morphometric study of metacercariae and adults of Pseudamphistomum truncatum (Opisthorchiidae) from roach (Rutilus rutilus) and wild American mink (Mustela vison)

The presence of metacercariae and adults of the trematode Pseudamphistomum truncatum in roach and mink, respectively, was recorded in Lake Fure North of Copenhagen, Denmark. This zoonotic digenean opisthorchiid represents a threat to humans due to its ability to infect the biliary system following ingestion of inadequately processed infected fish. Therefore precise species identification of infective metacercariae in fish used for human consumption is essential. Due to the relatively limited information on metacercarial identity obtained by morphometric studies a series of molecular techniques were used to link the larval parasite in fish with the un-equivocally diagnosed adults in the biliary system of the mink. By the use of carefully selected polymerase chain reaction (PCR) primers and subsequent sequencing of the ITS region from both metacercariae and adults full sequence identity of both metacercariae and adults were confirmed. The presence of this parasitosis in fish from a lake used for both commercial and recreational fisheries call for hygienic alerts in order to prevent accidental human infection with this opisthorchiid.     

Impact of scale on morphological spatial pattern of forest

Assessing and monitoring landscape pattern structure from multi-scale land-cover maps can utilize morphological spatial pattern analysis (MSPA), only if various influences of scale are known and taken into account. This paper lays part of the foundation for applying MSPA analysis in landscape monitoring by quantifying scale effects on six classes of spatial patterns called: core, edge, perforation, branch, connector and islet. Four forest maps were selected with different forest composition and configuration. The sensitivity of MSPA to scale was studied by comparing frequencies of pattern classes in total forest area for various combinations of pixel size (P) and size parameter (S). It was found that the quantification of forest pattern with MSPA is sensitive to scale. Differences in initial composition and configuration influence the amount but not the general tendencies of the variations of morphological spatial pattern (MSP) class proportions with scale. Increase of P led to data generalization resulting in either a removal of the small size features or their potential transformation into other non-core MSP classes, while an increase of S decreases the MSP core area and this process may transform small core areas into the MSP class islet. We established that the behavior of the MSPA classes with changing scale can be categorized as consistent and robust scaling relations in the forms of linear, power, or logarithmic functions over a range of scales.     

Identification and characterization of pathotypes in <Emphasis Type="Italic">Puccinia horiana</Emphasis>, a rust pathogen of <Emphasis Type="Italic">Chrysanthemum</Emphasis> x <Emphasis Type="Italic">morifolium</Emphasis>

Puccinia horiana is the causal agent of chrysanthemum white rust or Japanese rust. This microcyclic autoecious rust has a quarantine status and can cause major damage in the commercial production of Chrysanthemum x morifolium. Given the international and often trans-continental production of planting material and cut flowers of chrysanthemum and the decreasing availability of registered fungicides in specific regions, breeding for resistance against P. horiana will gain importance and will need to involve the appropriate resistance genes for the pathotypes that may be present. As pathotypes have not been well characterized in this system, the main objective was to build an international collection of isolates and screen these on a large collection of cultivars to identify different pathotypes. Using a robust and high throughput bioassay, we tested 36 selected cultivars with 22 individual single-pustule isolates of P. horiana. The isolates originated from three different continents over 4 different collection years and included some isolates from cultivars previously reported as resistant. In most cases the bioassays resulted in a clear scoring of interaction phenotypes as susceptible or resistant, while in several cases consistent intermediate phenotypes were found, often on specific cultivars. Twenty-four of the cultivars gave a differential interaction phenotype profile. All isolates produced a unique profile, infecting a minimum of 4 and a maximum of 19 differential cultivars. Based on the Person analysis of these profiles, this pathosystem contains at least seven resistance genes (and seven avirulence genes), demonstrating the highly complex race structure in this pathosystem.     

Growth Response of Various Perennial Grasses to Increasing Salinity

ABSTRACT

Although the effect of salinity on plant growth has been the focus of a substantive research effort, much of this research has failed adequately to separate the various growth-limiting aspects of salinity; thus, the results are confounded by multiple factors. Eight perennial grass species were grown in a sand-culture system dominated by sodium chloride (NaCl) [electrical conductivities (ECs) between 1.4 and 38 dS m^?1], with sufficient calcium (Ca) added to each treatment to ensure that Na-induced Ca deficiency did not reduce growth. Of the eight perennial grass species examined, Chloris gayana cv. ‘Pioneer’ (Rhodes grass) was the most salt-tolerant species, while Chrysopogon zizanioides cv. ‘Monto’ (vetiver) was of only moderate tolerance. However, observed salinity tolerances tended to be lower than those expected from published values based on the threshold-salinity (bent-stick) model. This discrepancy may be due in part to differences in the evapotranspirational demand between studies; i.e., an increase in demand accelerates the accumulation of sodium (Na) in the shoots and hence decreases apparent salinity tolerance. It was also observed that the use of a non-saline growth period (to allow seed germination and establishment) results in the overestimation of vegetative salinity tolerance if not taken into consideration. This situation is particularly true for species of low salt tolerance, due to their comparatively rapid growth in the non-saline medium compared with growth at full salinity.     

Mechanical transmission of porcine reproductive and respiratory syndrome virus throughout a coordinated sequence of events during warm weather

Mechanical transmission of porcine reproductive and respiratory syndrome virus (PRRSV) throughout a coordinated sequence of events that replicated common farm worker behavior during warm weather (10°C to 16°C) was assessed using a field-based model. The model involved fomites (boots and containers), vehicle sanitation, transport, and personnel movement. In a previous study, the model successfully demonstrated mechanical transmission of PRRSV in 8 out of 10 replicates during cold weather. A field strain of PRRSV was inoculated into carriers consisting of soil samples, which were adhered to the undercarriage of a vehicle. The vehicle was driven approximately 50 km to a commercial truck washing facility where the driver's boots contacted the carriers during washing, introducing the virus to the vehicle interior. The vehicle was then driven 50 km to a simulated farm site, and the driver's boots mechanically spread virus into the farm anteroom. Types of containers frequently employed in swine farms contacted drippings from the footwear on the anteroom floor. The truck wash floor, vehicle cab floor mats, boot soles, anteroom floor, and the ventral surface of containers were sampled to track the virus throughout the model. Ten replicates were conducted, along with sham-inoculated controls, and control replicates. In 2 replicates, infectious PRRSV was detected on the anteroom floor and in 1 replicate, infectious PRRSV was detected on the surface of the container by swine bioassay. All sham-inoculated controls and protocol controls were negative. These results indicate that mechanical transmission of PRRSV throughout a coordinated sequence of events in warm weather can occur, but in contrast to data from studies conducted during cold weather, it appears to be a relatively infrequent event.     

IMAGING DIAGNOSIS—RADIOGRAPHIC,ULTRASONOGRAPHIC, COMPUTED TOMOGRAPHIC,AND FLUOROSCOPIC APPEARANCE OF A DISTAL PELVIC LIMB ARTERIOVENOUS MALFORMATION IN A YOUNG GERMAN SHEPHERD DOG

A German shepherd puppy presented for evaluation of a suspected arteriovenous fistula on the distal aspect of the right pelvic limb. Radiographs demonstrated expansion and resorption of the tarsal and metatarsal bones, and ultrasound detected a vascular abnormality. Using computed tomographic angiography, a complex arteriovenous malformation (AVM) involving the distal tibia, tarsus, and the metatarsus and an osteochondritis dissecans (OCD) lesion of the talus were identified. Based on these findings, therapeutic limb amputation was performed. Fluoroscopic angiography, vascular casting, and dissection were then used to further characterize features of this previously unreported AVM with concurrent bony lesions and OCD.