Characterization ofSolanum tuberosum simple sequence repeats and application to potato culiwar identification

With the continued introduction of new potato cultivars, accurate identification is becoming difficult but is essential for maintaining cultivar integrity and Plant Breeders’ Rights. Hypervariable DNA sequences, referred to as simple sequence repeats (SSRs) or microsatellites, have been reported to be an excellent source of genetic markers. To determine the abundance, distribution, and composition of SSRs withinSolanium tuberosum, 252 sequences were searched for tetranucleotide and smaller SSRs with a minimum length of 20 nucleotides and a maximum discrepancy of two nucleotides. In total, 40 unique SSRs were observed in the 252S. tuberosum sequences examined and occurred at a frequency of one SSR every 8.1 kb. To assess the ability of site-specific amplified SSRs to identify potato cultivars, a simple (TCAC)_m and compound (TCAC)_m ? (CTT)_n SSR 5’ to the starch synthase gene and a compound (C)_p ? (CT)_q ? (AT)_r ? (G)_s SSR 5’ to the sequence encoding mature proteinase inhibitor I, were examined and shown to produce unique DNA profiles for 73 of 95 tetraploid cultivars. In total, 24 alleles were observed at these loci and the accurately sized amplified DNA products can be used to establish a database for cultivar identification. Site-specific amplified alleles were somatically stable and have been conserved in clonal variants of Russet Burbank independently maintained for almost seven decades, a characteristic essential for cultivar identification. As genetic markers, the abundant, informative, and easily examined site-specific amplified alleles of SSRs are ideal for quickly and accurately determining cultivar identity of S.tuberosum ssp.tuberosum.     

Rhabdochona longleyi sp. n. (Nematoda: Rhabdochonidae) from blind catfishes, Trogloglanis pattersoni and Satan eurystomus (Ictaluridae) from the subterranean waters of Texas

A new nematode species, Rhabdochona longleyi sp. n. is described from the intestine of two species of blind catfishes, Trogloglanis pattersoni Eigenmann (type host) and Satan eurystomus Hubbs et Bailey (both fam. Ictaluridae, Siluriformes) from the subterranean waters (artesian wells penetrating San Antonio pool of Edwards Aquifer) of Texas, USA. It is characterized largely by the presence of only six anterior teeth in the prostom, simple deirids, by the shape and length of spicules (0.42 to 0.50 mm and 0.093-0.102 mm), shape of the tail tip (rounded), and by filamented eggs. R. longleyi probably adapted to the environment of the aquifer by utilizing available troglobitic crustaceans instead of aquatic insects as an intermediate host.     

Induction of estrus in greyhound bitches with prolonged idiopathic anestrus or with suppression of estrus after testosterone administration

Twelve anestrous adult Greyhound bitches were used to study a regimen for induction of estrus. Once daily, 7 bitches were given diethylstilbestrol (DES; 5 mg, PO) until sanguineous vaginal discharge and vulvar edema were observed (designated as day 1 of proestrus) and for 2 days thereafter. If no response was elicited after 7 days, a doubled DES dose was given for up to an additional 7 days. Luteinizing hormone (5 mg, IM) was given on day 5 of proestrus, and follicle-stimulating hormone (10 mg, IM) was given on days 9 and 11 of proestrus. Bitches were bred once on day 13. Five bitches were used as a control group; they were given candy tablets for 7 days (first day on tablets, treatment day 1) and 0.9% NaCl (1.0 ml, IM) on treatment days 12, 16, and 18. The 7 bitches treated with DES had a mean proestrus period of 7.7 days and a mean estrus period of 5.7 days up to the day of mating. After mating, they had a mean gestation interval of 64 days and delivered a mean of 4 pups/litter. In 5 bitches, initial treatment with 5 mg of DES/day induced proestrus within 7 days; however, in 2 bitches, additional treatment with 10 mg of DES/day was needed for 5 and 6 days, respectively. Serum estradiol-17 beta and progesterone concentrations remained at base line during the period of DES treatment. Concentrations of both hormones increased after injection with luteinizing hormone and remained high for the next 4 days.(ABSTRACT TRUNCATED AT 250 WORDS)     

Breeding for Highly Fertile Isolates of Nectria haematococca MPVI that are Highly Virulent on Pea and In Planta Selection for Virulent Recombinants

ABSTRACT The heterothallic ascomycete Nectria haematococca mating population VI (anamorph Fusarium solani) is a broad host range pathogen. Field isolates of this fungus that are pathogenic on pea tend to be female sterile, of low fertility, and the same mating type (MAT-1), whereas female fertile isolates of either mating type that are highly fertile tend to be nonpathogenic on this plant. To facilitate genetic analysis of traits that may be important in the ability of N. haematococca to parasitize peas, a breeding project was undertaken to produce hermaphroditic isolates of each mating type that are highly fertile and highly virulent on peas. Although the association of high virulence on peas with female sterility and the MAT-1 mating type was not completely broken, isolates with high fertility and high virulence on peas were bred within two generations. Highly virulent progeny were also isolated by an alternative method in which pea plants were inoculated with a mixture of ascospores from a cross between two moderately virulent parents. Whereas all ascospores isolated without selection in planta had lower virulence than the parents, many isolates recovered from diseased tissue were more virulent than the parental isolates. Some of the recovered isolates were shown by restriction fragment length polymorphism analysis to be genetic recombinants of the parents, demonstrating that the pea tissue selected virulent recombinants. All highly virulent isolates tested had the ability to detoxify the pea phytoalexin pisatin, again showing a link between this trait and pathogenicity on the pea.     

Pathological fractures secondary to metaphyseal osteopathy in a dog.

A four-month-old German Shepherd Dog (GSD) was admitted with bilateral non-weight bearing hindlimb lameness and pyrexia. A diagnosis of bilateral distal femoral fractures secondary to metaphyseal osteopathy was made on the basis of clinical signs, radiography and biopsy. The dog returned to normal function following conservative management. As far as the authors are aware there are no previous reports of pathological fractures secondary to this condition.