Behavioural responses to visual environment in early stage Atlantic cod Gadus morhua L. larvae

Marine fish larvae exhibit species‐specific sensitivity to light, which changes during ontogeny. Our aim was to explore how visual environment, characterized by light intensity, microalgae addition and wall colour, affects spatial distribution of Atlantic cod larvae. We applied two different small‐scale factorial designs, each of them as a series of independent short‐term trials at fixed larval ages from 5 to 35 days post hatch (DPH). Positive phototaxis increased in larvae from 5 to ≈24 DPH, followed by reduced response at later ages. Effects from the experimental factors on larval behaviour changed with age, and significant interactions between factors were present. Algae significantly affected larvae only at 5 DPH, increasing phototactic response. White wall colour induced distribution of larvae close to the tank walls at all ages. The experimental approach demonstrated clear effects from visual environment on larval distribution, and revealed both relative importance of individual factors, interactive effects and temporal changes due to larval ontogeny. Our results suggest that by fine‐tuning the visual environment in tanks, the larval distribution may be managed to improve overall rearing conditions through a more even distribution with reduced closeness to tank walls.     

Immunisation with a combination of two complementary feline calicivirus strains induces a broad cross-protection against heterologous challenges

Feline calicivirus (FCV) is characterised by a high degree of antigenic variation potentially compromising vaccine efficacy. Inclusion of several FCV strains or antigens in current vaccines could be a means to improve protection against antigenically distinct isolates. This study evaluated the synergy between two FCV strains (FCVG1 and FCV431) by comparing immunity induced by either strain with that provided by a combination of the two strains against an heterologous challenge with antigenically distant FCV strains (FCV393 and FCV220). Thirty-two SPF kittens were randomly allocated to four groups of eight cats in each group. Groups B, C and D cats were vaccinated once subcutaneously with strains FCVG1, FCV431, and FCVG1 + FCV431, respectively. Each kitten received a total dose of 10(3.4) CCID50 of FCV. Control group A was not immunised. On day 31, four cats from each group were challenged oronasally with FCV220 and four cats with FCV393. Following challenge, the cats were monitored for clinical signs, viral shedding and antibody responses. FCV220 and FCV393 induced severe clinical signs in control cats typical of FCV infection. Immunisation with both strains mixed together induced higher neutralizing antibody titres against FCV220 and FCV393 strains on average. Protection was observed in all groups, however combination of the two strains resulted in a better clinical protection and reduction of virus shedding after heterologous challenge. A moderate correlation was observed between neutralizing antibody titres at the time of challenge and protection against clinical signs. These results indicated that vaccines combining antigens from different FCV strains may induce a broader heterologous protection.     

The fate of condensed tannins during litter consumption by soil animals

Condensed tannins (CT) can strongly affect litter decomposition, but their fate during the decomposition process, in particular as influenced by detritivore consumption, is not well understood. We tested the hypothesis that litter CT are reduced by the gut passage of two functionally distinct detritivores of Mediterranean forests, the millipede Glomeris marginata, and the land snail Pomatias elegans, as a fixed proportion of initial litter CT, but more so in Pomatias since snails are known to have a more efficient enzymatic capacity. Contrary to our hypothesis, both detritivore species reduced litter CT to near zero in their faecal pellets irrespective of the wide range in initial leaf litter CT concentrations of 9-188 mg g⁻¹ d m among three Mediterranean tree species (Pistacia terebinthus, Quercus ilex, Alnus glutinosa) and different decomposition stages of their litter. The almost complete disappearance of CT even from some litter types highly concentrated in CT, due to either degradation by gut microorganism or complexation of CT into insoluble high molecular weight structures, suggests a high “de-tanning” efficiency across functionally distinct detritivore species. The transformation of CT-rich litter into virtually CT-free faecal pellets by detritivores might be highly relevant for the subsequent decomposition process in ecosystems with a high macrofauna abundance and CT-rich plant species such as Mediterranean forests.     

在人工接种和自然感虫情况下美洲黑杨后代对桑天牛抗性的研究

杨树 (Ｐｏｐｕｌｕｓｓｐｐ .)是我国主要造林和工业用材树种之一 ,据统计我国杨树人工林面积达 666×1 0 4ｈｍ2 (王世绩 ,1 995 )。但杨树天牛危害十分猖獗 ,其中光肩星天牛 (Ａｎｏｐｌｏｐｈｏｒａｇｌａｂｒｉｐｅｎｎｉｓ)和黄斑星天牛 (Ａｎｏｐｌｏｐｈｏｒａｎｏｂｉ     

Induction of T helper type 2 immunity by a point mutation in the LAT adaptor

The transmembrane protein LAT (linker for activation of T cells) couples the T cell receptor (TCR) to downstream signaling effectors. Mice homozygous for a mutation of a single LAT tyrosine residue showed impeded T cell development. However, later they accumulated polyclonal helper T (TH) cells that chronically produced type 2 cytokines in large amounts. This exaggerated TH2 differentiation caused tissue eosinophilia and massive maturation of plasma cells secreting to immunoglobulins of the E and G1 isotypes. This paradoxical phenotype establishes an unanticipated inhibitory function for LAT that is critical for the differentiation and homeostasis of TH cells.     

CoRoT measures solar-like oscillations and granulation in stars hotter than the Sun

Oscillations of the Sun have been used to understand its interior structure. The extension of similar studies to more distant stars has raised many difficulties despite the strong efforts of the international community over the past decades. The CoRoT (Convection Rotation and Planetary Transits) satellite, launched in December 2006, has now measured oscillations and the stellar granulation signature in three main sequence stars that are noticeably hotter than the sun. The oscillation amplitudes are about 1.5 times as large as those in the Sun; the stellar granulation is up to three times as high. The stellar amplitudes are about 25% below the theoretic values, providing a measurement of the nonadiabaticity of the process ruling the oscillations in the outer layers of the stars.     

Ultrasound-guided core needle biopsy in dogs with thyroid carcinoma

Currently, a histological diagnosis of highly vascularized canine (c) thyroid carcinoma (TC) is primarily obtained following excisional biopsy (EB) through thyroidectomy. Non-EBs are contraindicated in unresectable invasive cTCs due to their highly vascularized nature, which subsequently, lack histological diagnosis. We hypothesised ultrasound-guided core needle biopsy (UGCNB) to be a safe biopsy technique to obtain an accurate histological diagnosis in unresectable TCs. Nine client-owned dogs with suspected naturally occurring TC, presented for surgical excision, were included. First, a UGCNB was taken from the cervical tumour, followed by EB. Haemorrhage following UGCNB was evaluated preoperatively and once the tumour was surgically exposed by visual inspection and ultrasonography. Histological analysis, including cell organisation, tumour capsular and vascular invasion, and immunohistochemistry were performed and compared between both biopsy specimens (i.e., UGCNB and EB) of the same dog. Pre- and peroperative visual inspection revealed minor, localised haemorrhage, subsequent to the UGCNB, in 7/9 dogs. Histology of the EBs confirmed TC in 8/9 dogs and was inconclusive in 1/9 dogs. Histology of the UGCNBs revealed neoplastic thyroid tissue in 7/9 UGCNBs and was inconclusive in 1/9 UGCNBs. The remaining UGCNB contained no mass related tissue and was, therefore, excluded. Histological parameters (i.e., cell organisation, tumour capsular and vascular invasion) were not concordant between 6/8 included UGCNBs and their respective EB. Immunolabelling for thyroglobulin and calcitonin was concordant between all eight included UGCNBs and their respective EB. The remaining evaluated immunohistochemical markers (i.e., cyclooxygenase-2 [COX-2], P-glycoprotein and vascular endothelial growth factor [VEGF]) were concordant between the included UGCNBs and the EBs in 6/8 dogs. To conclude, UGCNBs can be safely obtained in suspected cTCs and enable a reliable diagnosis of the thyroid origin, thyroid cell origin and potential therapeutic markers such as COX-2, P-glycoprotein and VEGF. Subsequently, UGCNB enables clinicians to establish an individually tailored treatment plan in dogs with unresectable TC.     

Climate change will affect the ability of forest management to reduce gaps between current and presettlement forest composition in southeastern Canada

Landscape Ecology - Forest landscapes at the boreal–temperate ecotone have been extensively altered. Reducing the gap between current and presettlement forest conditions through...     

How climate change might affect tree regeneration following fire at northern latitudes: a review

New Forests - Climate change is projected to increase fire severity and frequency in the boreal forest, but it could also directly affect post-fire recruitment processes by impacting seed...