Genetic resistance to Leukosis virus infection: effects on mortality and egg production in Leghorn hens

The influence of genotypic differences in resistance to infection from Lymphoid Leukosis (LL) on mortality and egg production was studied in three pairs of sublines. One subline of each pair had been selected for resistance and the other for susceptibility to infection. At 10 months of age, almost no hens with neutralising antibodies against LL were found in the resistant sublines, while in each susceptible subline more than 40% of the hens had LL antibodies. At 21 months of age, very few hens of the resistant sublines had group-specific (gs) antigen in their eggs. Susceptible sublines differed considerably in this respect, from 81% gs antigen-positive hens in one subline to 9% or no positive hens in the others. On the whole, the susceptible sublines had 6% higher mortality during the laying period (8 months) but the size of the difference was influenced by vaccination against Marek's disease (MD) and varied considerably between pairs of sublines. Significant interactions between strain and genotype of resistance to LL infection were observed for mortality from "other causes" in hens vaccinated against MD, as well as for mortality from "Leukosis" and from "MD" in non-vaccinated hens. The average rate of lay from 1 to 8 months was 8% lower in susceptible hens. In the subline with the highest frequency of eggs containing LL group-specific antigen in the albumen, the reduction of laying rate was twice as large as in the other susceptible sublines.     

Immunohistochemical expression of HER - 2 and Ki - 67 in granulosa cell tumor in bitches

Granulosa cell tumour, an ovarian neoplasm of stromal origin, is an important tumour related to oestrogenic dominance syndrome and cystic endometrial hyperplasia–pyometra complex. In order to analyse ovarian tumour´s malignant potential, immunohistochemical markers can be used, such as anti-HER2 and anti-Ki-67. The aim of this study was to evaluate the expression of immunohistochemical markers HER-2 and Ki-67 in granulosa cell tumour from bitches´ ovaries. In HER-2 immunomarker analysis using the HercepTest^® method, most tumours were classified as 2+ (moderate labelling). Concerning Ki-67 immunomarker, only one case was described as having a high proliferative index. An association was found between immunostained cell percentage by anti-HER-2 antibodies and high pleomorphism, represented by the pattern of follicular/trabecular tumour arrangement. There was no correlation between anti-Ki-67 and anti-HER-2 antibody immunostaining intensities, probably due to only one case with a high Ki-67 index. With an effective protocol for HER-2 and Ki-67 immunohistochemical identification in granulosa cell tumours in bitches, it was possible to characterize this neoplasm proliferation profile.     

The Ecological Concept of Costs of Induced Systemic Resistance (ISR)

Plant defence is thought to provide benefits for the defended plants. Theoretical concepts must, therefore, explain why there is variation in defensive traits, which naively might be assumed to be present constitutively in fixed high amounts. Explanations are mainly based on the assumption of fitness costs. Investment in defence is thought to reduce the fitness of plants in enemy-free environments. Fitness costs often result from allocation costs, i.e. allocation of limited resources to defence, which then cannot be used for growth or other fitness-relevant processes. This theoretical concept can provide a useful tool for the interpretation of induced plant responses against pathogens, named induced systemic (or systemic acquired) resistance (ISR or SAR). Phenotypic plasticity, leading to induced responses, might have evolved mainly to reduce costs, since investment in defence is restricted to situations actually requiring defence. ISR can incur allocation costs and other, indirect costs, which ultimately may lead to fitness costs. Evolution of any defensive trait depends on both what a plant ideally 'should do and what it actually 'is able to do. Costs of defence constrain its expression. This might have important influences on the evolution of plant defensive traits, as well as on the exploitation of natural defences in agricultural crop protection.     

Some long-term observations on cyclical and seral processes in Dutch heathlands

Changes over a period of 10–30 years in the vegetation of some Dutch heathlands were studied, using aerial photographs and information derived from observations and permanent plots. The sites studied are situated in (formerly) Calluna vulgaris-dominated heathlands, known to be infested in the past by the heather beetle Lochmaea suturalis, Thoms., followed by a Calluna die-off. No interference by management practices had interrupted the natural changes in the vegetation following the infestation. Evidence for both seral and cyclical changes is presented. It is concluded that abiotic factors, i.e. physiographically controlled minor differences in the soil type, determine whether a cyclical or seral change will occur.     

Histopathological findings in the early diagnosis of granulosa cell tumour in bitches

Granulosa cell tumour (GCT) is a majorly observed ovarian tumour in female dogs. It is essential to diagnose GCT in its initial phase before any symptoms occur, as histological and physiological differences may be observed based on the evolution of this neoplasia. This study aimed to analyse the anatomic histopathology of GCT in its initial stage, with findings of ovaries not yet with the suspicion of neoplasms in the Canis familiaris. A sample including 55 ovaries presented GCT in 40 female dogs. The histopathological analysis was performed considering the intensity of pleomorphism, vascularization and inflammatory infiltrate. Furthermore, we evaluated the mitoses count in 10 fields using 40× magnification. Out of the 40 animals evaluated, 62.5% (25/40) presented the tumour in only one ovary. The Call‐Exner corpuscle was present in 65% (26/40) of the cases. The follicular histological pattern was present in 52.5% (21/40) of the animals. The presence of the Call‐Exner bodies and the degree of tumour cell pleomorphism (p = 0.033) were associated. Moreover, the degree of vascularization and the intensity of the inflammatory infiltrate were also related (p = 0.001). In addition, there was a positive relationship between the increase in pleomorphism and the mean age of the animals (p = 0.044). This study confirmed that the appearance of this tumour may precede any clinical symptomatology. In this study, the most frequent histopathological pattern was the follicular. The characteristics of the granulosa cell tumour diagnosed early were poorly pleomorphic cells, low mitotic index and presence of Call‐Exner body.     

Untersuchungen über die Nahrungsaufnahme der Stabheuschrecke(Carausius morosus)

Ohne Zusammenfassung Mit 3 Abbildungen     

Species-specific recognition of single-stranded RNA via toll-like receptor 7 and 8

Double-stranded ribonucleic acid (dsRNA) serves as a danger signal associated with viral infection and leads to stimulation of innate immune cells. In contrast, the immunostimulatory potential of single-stranded RNA (ssRNA) is poorly understood and innate immune receptors for ssRNA are unknown. We report that guanosine (G)- and uridine (U)-rich ssRNA oligonucleotides derived from human immunodeficiency virus-1 (HIV-1) stimulate dendritic cells (DC) and macrophages to secrete interferon-alpha and proinflammatory, as well as regulatory, cytokines. By using Toll-like receptor (TLR)-deficient mice and genetic complementation, we show that murine TLR7 and human TLR8 mediate species-specific recognition of GU-rich ssRNA. These data suggest that ssRNA represents a physiological ligand for TLR7 and TLR8.     

Capture of atmospheric ammonium by grassland canopies

Air pollution can cause a decline in species through acidification of the habitat. New data suggest that the decline may be due to eutrophication rather than acidification. In Western Europe, eutrophication largely results from atmospheric ammonium deposition. The amount deposited on vegetation is a function of its canopy structure. Deposition on grasslands has been underestimated, and a significant amount of the deposited ammonium appears to be assimilated by the plant canopy. These quantities are sufficient to initiate changes in the competitive relations among the plant species.     

Zinc experiments on potatoes in the San Luis Valley of Colorado

Seven field trials with Zn were carried out in 1965, 1966, and 1967 to determine source and placement effects of ZnEDTA (Zn ethylene-diaminetetraacetate) and ZnSO₄ on the yield and composition of potatoes grown in the San Luis Valley of Colorado. Application of Zn increased the yield of U.S. No. 1 potatoes from 16 to 95% on soils having less than 4.8 ppm of 0.1NHCI-extractable Zn. No yield response was obtained on soils having greater than 5.5 ppm of extractable Zn. Uptake of Zn was greater from soil-applied ZnEDTA than from soilapplied ZnSO₄. Banding ZnSO₄ approximately 3 inches (7.6 cm) directly below the seed piece was more efficient than discing it or sidebanding it 5 inches (12.7 cm) to the side and 3 inches (7.6 cm) below the seed piece. Two foliar sprays of either ZnSO₄ or ZnEDTA solutions (0.5%) were also effective in correcting Zn deficiency. Zinc content of the foliage was not a good indicator of the Zn nutrition of potato plants.