Correction to: Population genetic structure of lumpfish along the Norwegian coast: aquaculture implications

The original version of this article unfortunately contained an error where the figure caption for Figures 3 and 4 was mixed.     

Variations of Neospora caninum antibody levels in milk during lactation in dairy cows

A longitudinal study was performed to investigate the variations of Neospora caninum antibody levels in individual milk during lactation as well as the association between antibody levels in serum and milk. Serum and milk samples of 15 milking cows were collected between February 2003 and September 2004 in three smallholder dairy farms in Khon Kaen province in northeast Thailand. All samples were analyzed for presence of antibodies by an N. caninum iscom ELISA test kit and the results were given as percent positivity (PP). The effects of time between calving and sampling, lactation number, and season on milk and serum PP were studied using Generalized Estimation Equations methods. All cows were antibody positive in either milk or serum at the first two consecutive samplings. Although serum and milk PP varied considerably, milk PP was consistently positive throughout the study. Cows of all lactation groups had a higher adjusted mean of milk PP at calving compared to later months after calving although the only significant difference was in first lactation. Serum and milk PP were always lower in first lactation than in second and later lactations. An adjusted mean of milk PP for cows classified as having serum PP> or =55 was significantly (P<0.05) higher than that of cows classified as having lower serum PP. Our results indicate that individual milk can be an alternative material to demonstrate presence of N. caninum antibodies in lactating cows.     

Evaluation of an iscom ELISA used for detection of antibodies to Neospora caninum in bulk milk

The intracellular parasite Neospora caninum is increasingly recognized as an important cause of abortion and stillbirth in cattle. Presence of specific antibodies indicates infection, and the immunostimulating complex (iscom) enzyme-linked immunoassay (ELISA) has previously been evaluated for use on individual milk and sera. In the present study, this test is investigated for use on bulk milk. In this study, 124 herds were used to analyse the relationship between within-herd prevalences based on individual sera and bulk milk optical densities. The individual test results were translated into a herd-level result, which enabled comparison of the bulk milk test result to the aggregate of individual serum results. The relative contribution of milk from cows with different milk yield and antibody status to the tank, i.e. its composition, was expected to influence the outcome of the bulk milk test. Therefore, sensitivity and specificity were calculated at different cut-off levels, not only using a standard cross-tabulation technique, but also a logistic regression model. By using the latter method, the sensitivity and specificity could be estimated adjusting for milk yield covariates. Specificity was estimated to be high ( approximately 98%) at the 0.20 cut-off, which can be used as a decision threshold to rule in infection. With more equal emphasis on sensitivity and specificity, a lower cut-off should be used. Although infection cannot be completely ruled out, herds with test results below 0.05 are highly likely to be non-infected. The within-herd prevalence of false negative herds is probably less than 10-15% at this level. From what is known about test performance at the individual level and the prevalence of infection, the estimate of the specificity of the bulk milk test should be quite accurate while the sensitivity is likely to be underestimated. We confirmed that the performance of the bulk milk test depends on the milk tank composition. In particular the milk yield of cows with high antibody levels affects the probability of a positive outcome of the bulk milk test.     

两种普鲁兰类酵母菌株Aureobasidium pullulans对三种核果类褐腐病菌Monilinia laxa,Monilinia fructicola和Monilinia fructigena的生物控制作用

本试验研究了从"Redhaven"桃果肉中分离得到的两种拮抗酵母菌株L1和L8对三种核果类褐腐病原菌(Monilinia laxa,Monilinia fructicola及Monilinia fructigena)的离体和活体拮抗效果。这两种拮抗菌株是经初步验证能够减轻桃和油桃的褐腐病症状后筛选出的,并最终通过分子生物学及形态学手段鉴定为Aureobasidium pullulans(出芽短梗霉菌)。通过活体接种三种褐腐病菌的试验研究发现,两种拮抗菌的高压灭菌悬液及无菌过滤液对果实褐腐病的发生均无抑制作用,而含有L1和L8菌株的菌悬液可完全抑制M.laxa和M.fructicola引起的褐腐病的发生,并使M.fructigena引起的褐腐病发病率分别降低70%和90%。在另一项试验中,将油桃用两种拮抗菌液处理后接种三种褐腐病菌,然后将其在0℃下贮藏21 d,再在20℃下放置7 d。结果表明,低温抑制了褐腐病的发生,处理和对照果实均无褐腐病的症状。但在20℃下放置7 d后,对照果实的褐腐病发病率均超过了45%,而LI和L8处理分别可以将接种M.fructigena病原菌果实褐腐病的发病率降低89.8%和91.2%,说明两种拮抗菌的处理可完全抑制接种M.laxa和M.fructicola引起的果实褐腐病的发生。两种拮抗酵母菌株的最佳抑菌浓度为108CFU.mL-1,L1在107CFU.mL-1浓度时也具有较好的抑菌效果。L8菌株在107CFU.mL-1浓度时对由M.fructigena和M.fructicola引起的果实褐腐病无抑制活性,处理与对照果实无差异。而对于接种了M.laxa的油桃果实,与对照相比,107CFU.mL-1浓度的L8菌株却可显著降低褐腐病的发病率。尽管在0℃和20℃下贮藏的油桃果实伤口处的L1和L8菌的数量增长较慢,但已经足够控制果实褐腐病的发生。综上所述,本项研究确定了可作为开发采后生物杀菌剂活性成分的两种A.pullulans拮抗菌株,并用于抑制引起核果类作物采后严重经济损失的三种Monilinia真菌。     

Validation of a Neospora caninum iscom ELISA without a gold standard

Neospora caninum is an intracellular parasite which causes abortion in cattle worldwide. One problem in the validation of the different methods for demonstration of this parasite is the lack of an appropriate gold standard. To validate an immunostimulating complex (iscom) enzyme-linked immunoassay (ELISA) used to detect antibodies to N. caninum, sera from 244 cattle in five Swedish dairy herds infected with N. caninum were analysed. The sera also were analysed by a standard indirect-fluorescent antibody test (IFAT). The results obtained by the two tests were compared using the Gibbs sampler. Gibbs sampling is a latent-class approach based on Bayesian statistics; neither test is assumed to be more correct in stating the true status of infection. The Gibbs sampler was run using both informative and non-informative prior probabilities. We also simulated different cut-offs in the iscom ELISA (providing data to inform selection of optimal cut-off values for different applications).The ELISA produced fewest incorrect test results over all at a cut-off value of 0.200. The sensitivity and specificity at this cut-off were 99 and 96%, respectively. The IFAT had a high specificity (99%) but a lower sensitivity (78%) than expected-confirming that the IFAT cannot be treated as a true gold standard. Sensitivity and specificity of the ELISA were presented in a two-graph receiver operating characteristic (TG-ROC) plot. Any cut-off between 0.150 and 0.300 will have both sensitivity and specificity > or =95%. Optical densities of < or =0.150 and > or =0.550 (or > or =0.350) were suggested as limits to rule out and rule in infection, respectively.     

Investigation of Chlamydophila spp. in dairy cows with reproductive disorders

Background

Reports worldwide indicate high prevalence of Chlamydophila spp. infection in cattle. To assess the prevalence in Sweden, 525 cows in 70 dairy herds with reproductive disorders was investigated.

Methods

To detect antibodies two commercially available kits were used. Moreover, 107 specimens, including vaginal swabs, organ tissues and milk were analysed by Polymerase Chain Reaction (PCR).

Results

Two (0.4%) cows were seropositive in the Pourquier Cp. abortus ELISA. The seroprevalence with the Chekit ELISA was 28% with no difference between cases and controls. Five specimens were positive in real-time PCR and further analysed by nested PCR. Cp. pecorum was confirmed by partial omp1 DNA sequencing of the nested PCR product of vaginal swabs from control cows.

Conclusion

The results suggest that Cp. abortus infection is absent or rare in Swedish cows whereas Cp. pecorum is probably more spread. They also suggest that Chlamydophila spp. are not related to reproduction disorders in Swedish cattle.     

PML regulates apoptosis at endoplasmic reticulum by modulating calcium release

The promyelocytic leukemia (PML) tumor suppressor is a pleiotropic modulator of apoptosis. However, the molecular basis for such a diverse proapoptotic role is currently unknown. We show that extranuclear Pml was specifically enriched at the endoplasmic reticulum (ER) and at the mitochondria-associated membranes, signaling domains involved in ER-to-mitochondria calcium ion (Ca(2+)) transport and in induction of apoptosis. We found Pml in complexes of large molecular size with the inositol 1,4,5-trisphosphate receptor (IP(3)R), protein kinase Akt, and protein phosphatase 2a (PP2a). Pml was essential for Akt- and PP2a-dependent modulation of IP(3)R phosphorylation and in turn for IP(3)R-mediated Ca(2+) release from ER. Our findings provide a mechanistic explanation for the pleiotropic role of Pml in apoptosis and identify a pharmacological target for the modulation of Ca(2+) signals.     

Climate change,human impacts,and the resilience of coral reefs

The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.