The potential for the Rapid Screening of Potato Cultivars (Solanum tuberosum) for Resistance to Powdery Scab (Spongospora subterranea) using a Laboratory Bioassay

Powdery scab of potato, once established in a field, is difficult to control because of the longevity of the resting spores (cystosori) of the causal organism, Spongospora subterranea f.sp. subterranea. Host resistance is likely to be the most efficient in a long-term control strategy for preventing build-up of field inoculum and spread of the disease. Resistance screening of potato cultivars is mostly done in laborious field trials where disease development is likely to be unpredictable. A bioassay with potato tissue cultured plantlets and cystosori as inoculum is described and was tested for its potential to screen potato cultivars at an early stage for their relative susceptibility to powdery scab by comparing the lab results with field data. With cystosori inoculum of Swiss origin, the laboratory test showed clear differences between the potato cultivars in the severity of zoosporangial root infection which correlated better with ranked tuber infection data, compared to root galling. There are apparent differences in the relative trends in susceptibility between roots and tubers of five selected cultivars when using naturally infested soil instead of prepared cystosori as inoculum in the lab bioassay. Furthermore, differences in the severity of zoosporangial root infection of two selected cultivars were found when cystosori from different countries where used as inoculum. A possible host genotype × pathogen interaction is discussed. The bioassay has the potential to screen and select for resistant material at an early breeding stage thus making field trials not unnecessary but more economical. It will allow the use of a standard set of pathogen collections and facilitate testing for inoculum virulence in infested soils.     

Influence of time of initiation of a prostaglandin F2alpha protocol in dairy cows with puerperal endometritis

A field trial was conducted to elucidate the effect of the time of initiation of a repeated PGF2alpha-application in a 14 day interval for treatment of endometritis in dairy cows. On a commercial dairy farm in Brandenburg, Germany, a total of 494 dairy cows were examined by rectal palpation and adspection for signs of endometritis (vaginal discharge, enlarged uterus) between day 20 to 26 post partum (dpp). We performed two further examinations by rectal palpation and external adspection to monitor the puerperal phase (34.-40. dpp, 55.-61. dpp). All cows with symptoms of an endometritis were treated with PGF2alpha (0.15 mg R-Cloprostenol, Preloban, Intervet Deutschland GmbH Unterschleissheim) twice in a 14-day interval. In the group "Early" (n = 146) the first injection of Cloprostenol was administered at time of the 1st examination. In the group "Late" (n = 129) an identical treatment was administered in cows with endometritis, however it was started 14 days later (34.-40. dpp). The incidence of endometritis was 57.7% in the group "Early" and 53.5% in the group "Late" at the first time of examination. The 1st service conception rates for treated cows were 34% in the group "Early" vs. 37% in the group "Late". In the group "Early" differences were found in days open between treated cows with endometritis and untreated controls without symptoms of endometritis (99.1 d vs. 110.8 d, p > 0.05). In the group "Late", days open for treated (106.8 d) and untreated cows (108.0 d) were similar. The severity of endometritis influenced the percentage of cows pregnant at 200 dpp. Regarding cows with a severe endometritis (E2 and E3) the percentage of pregnant cows 200 dpp was higher in the group treated early (E2: 78.4%; E3: 80.0%) than in the group with the late initiation of the treatment (E2: 68.6%; E3: 54.5%, p < 0.05). Cows with a moderate endometritis (E1) had a similar percentage of pregnant cows (200 dpp) as the untreated cows without endometritis. It is concluded that application of PGF2alpha in the 4th and 6th week post partum in a 14 day interval in cases of severe endometritis is more effective than the application of the same treatment two weeks later.     

Preliminary studies of serum acute-phase protein concentrations in hematologic and neoplastic diseases of the dog

Serum concentrations of acute-phase proteins (APPs): haptoglobin (Hp), ceruloplasmin (Cp), serum amyloid A (SAA), and C-reactive protein (CRP) were determined in healthy dogs (n = 15) and dogs with different diseases grouped as acute inflammation (I, n = 12), hematologic neoplasias (HT, including leukemia and lymphoma, n = 16), nonhematologic neoplasias (NHT, including epithelial, mesenchymal, and mixed, n = 20), and autoimmune hemolytic anemia (AIHA, n = 8). SAA and CRP were analyzed using commercially available enzyme-linked immunosorbent assay (ELISA) kits, and Hp and Cp were measured using colorimetric methods, all previously validated for use in dogs. Increased concentrations of all APPs were observed in all groups of diseased dogs, but statistical significance only was observed with Hp (I, P < .001; HT, P < .05), Cp (I, P < .05; AIHA, P < .01), and CRP (I, P < .001; HT, P < .001; AIHA, CRP P < .05). High variability in individual APPs within each group of diseases was found with no significant differences between leukemia and lymphoma as well as among different types of neoplasia. The AIHA group had smaller increases in Hp, SAA, and CRP but higher concentrations of Cp. When follow-up of individual cases was possible, a decrease in APPs generally was found in cases with favorable outcome. The results of this study suggest that neoplasia and hematologic diseases such as AIHA should be considered as possible causes of mild increases in APPs in dogs. Measurement of APPs may be helpful to assess clinical evolution and monitor treatment of these processes.     

Identification of ALS inhibitor‐resistant Amaranthus biotypes using polymerase chain reaction amplification of specific alleles

Summary Polymerase chain reaction (PCR) amplification of specific alleles (PASA) was adapted as a molecular marker‐based method for the rapid detection of point mutations in Amaranthus retroflexus and Amaranthus rudis leading to ALS inhibitor resistance. Two pairs of primers were designed for the specific amplification of alleles of the ALS gene of susceptible and resistant biotypes. The allele‐specific primer matched the desired allele, but mismatched the different allele at its 3′ end. Differentiation was carried out by comparison of the amplified DNA fragments in gel electrophoresis after PASA‐PCR. In A. rudis, differentiation was possible with one PCR and genomic DNA as probe. A ‘nested’ PCR was necessary for the differentiation of sensitive and resistant A. retroflexus. PASA is useful for the identification of resistant weed biotypes and also as a monitoring tool to map resistance occurrence and distribution. Advantages include the fast and clear separation of those plants with and without mutations at an early stage of development, its easy and consistent performance and quick results compared with existing resistance detection tests. These advantages, when combined with management strategies, enable further activities to reduce herbicide resistance.     

Infection of Tomicus piniperda (Col., Scolytidae) with Canningia tomici sp. n. (Microsporidia, Unikaryonidae)

Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8±0.4× 1.4±0.4m and 3.8±0.3×2.0±0.2m. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.     

Population Structure and Disease Development of Cryphonectria parasitica in European Chestnut Forests in the Presence of Natural Hypovirulence

ABSTRACT The Cryphonectria parasitica populations in two 6-year-old European chestnut (Castanea sativa) coppices were investigated in southern Switzerland over a period of 4 years. Occurrence of white isolates indicating an infection with Cryphonectria hypovirus, vegetative compatibility groups (VCGs), hypovirulence conversion capacity, and mating types were used to characterize the populations. Sampling of randomly chosen cankers in the first year yielded 59% white isolates in one and 40% in the other population. The distribution of the VCGs and mating types was similar among white and orange isolates, indicating a homogeneous infection of the two populations by the hypovirus. Fourteen VCGs were found in the first population, 16 VCGs in the second. Altogether, 21 VCGs were determined. The same three VCGs dominated in both populations, comprising more than 60% of all isolates. Several VCGs were represented only by white isolates. Five of the six most common VCGs were clustered in two hypovirulence conversion groups, with almost 100% hypovirus transmission within each cluster. Repeated sampling of the same cankers in 1990, 1992, and 1994 did not reveal an increase of white isolates. The portion of blighted stems rose from 37% to about 60% in both plots within 4 years. In this time, chestnut blight killed 15% and competition an additional 21% of the sprouts. Predominantly, sprouts with low diameters at breast height were killed. The growth rate of new cankers was high in their first year and decreased gradually in the following years. A role of hypovirulence in the decline of disease severity was evident since (i) cankers yielding white isolates grew slower and killed considerably fewer sprouts than cankers with orange isolates; and (ii) the majority of the cankers yielded white isolates at least once during the 4-year observation period.     

Effect of the manganese content in laying hen feed with different Ca and mineral levels on the egg shell quality and bone mineralization of hens]

Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality. Addition of mineral mixture or Ca grit to layer rations with adequate or higher Mn levels did not influence egg shell strength. High mineral content in a low manganese diet increased number of cracks by 3%. Strength, weight and ash content of tibia were significantly reduced by feeding a low mineral level. Addition of 50-150 mg Mn per kg low mineral diet normalized partially tibia stability in young hens. It was concluded that supplied dietary Manganese influences calcification positively only in young hens. High levels of Ca did not influence the effects of Mn. 50 mg Mn per kg layers mixture have been considered as an essential supply.     

Effect of heat treatment on the antioxidant activity of extracts from citrus peels

The effect of heat treatment on the antioxidant activity of extracts from Citrus unshiu peels was evaluated. Citrus peels (CP) (5 g) were placed in Pyrex Petri dishes (8.0 cm diameter) and heat-treated at 50, 100, or 150 degrees C for 10, 20, 30, 40, 50, and 60 min in an electric muffle furnace. After heat treatment, 70% ethanol extract (EE) and water extract (WE) (0.1 g/10 mL) of CP were prepared, and total phenol contents (TPC), radical scavenging activity (RSA), and reducing power of the extracts were determined. The antioxidant activities of CP extracts increased as heating temperature increased. For example, heat treatment of CP at 150 degrees C for 60 min increased the TPC, RSA, and reducing power of EE from 71.8 to 171.0 microM, from 29.64 to 64.25%, and from 0.45 to 0.82, respectively, compared to non-heat-treated control. In the case of WE from CP heat-treated at the same conditions (150 degrees C for 60 min), the TPC, RSA, and reducing power also increased from 84.4 to 204.9 microM, from 15.81 to 58.26%, and from 0.27 to 0.96, respectively. Several low molecular weight phenolic compounds such as 2,3-diacetyl-1-phenylnaphthalene, ferulic acid, p-hydroxybenzaldoxime, 5-hydroxyvaleric acid, 2,3-diacetyl-1-phenylnaphthalene, and vanillic acid were newly formed in the CP heated at 150 degrees C for 30 min. These results indicated that the antioxidant activity of CP extracts was significantly affected by heating temperature and duration of treatment on CP and that the heating process can be used as a tool for increasing the antioxidant activity of CP.