Alterations in glutamatergic transmission onto developing GABAergic systems, in particular onto parvalbumin-positive (Pv(+)) fast-spiking interneurons, have been proposed as underlying causes of ...several neurodevelopmental disorders, including schizophrenia and autism. Excitatory glutamatergic transmission, through ionotropic and metabotropic glutamate receptors, is necessary for the correct postnatal development of the Pv(+) GABAergic network. We generated mutant mice in which the metabotropic glutamate receptor 5 (mGluR5) was specifically ablated from Pv(+) interneurons postnatally, and investigated the consequences of such a manipulation at the cellular, network and systems levels. Deletion of mGluR5 from Pv(+) interneurons resulted in reduced numbers of Pv(+) neurons and decreased inhibitory currents, as well as alterations in event-related potentials and brain oscillatory activity. These cellular and sensory changes translated into domain-specific memory deficits and increased compulsive-like behaviors, abnormal sensorimotor gating and altered responsiveness to stimulant agents. Our findings suggest a fundamental role for mGluR5 in the development of Pv(+) neurons and show that alterations in this system can produce broad-spectrum alterations in brain network activity and behavior that are relevant to neurodevelopmental disorders.
A group of captive white‐spotted eagle rays Aetobatus narinari produced 20 offspring, with an unknown father. Part of the poisonous sting was removed from each fish and DNA was extracted from the ...epidermis for paternity research using eight microsatellite markers of which four were from another species Aetobatus flagellum. This non‐invasive sampling technique can be applied on all members of Myliobatiformes.
Koi herpesvirus (KHV) causes KHV disease (KHVD). The virus is highly contagious in carp or koi and can induce a high mortality. Latency and, in some cases, a lack of signs presents a challenge for ...virus detection. Appropriate immunological detection methods for anti‐KHV antibodies have not yet been fully validated for KHV. Therefore, it was developed and validated an enzyme‐linked immunosorbent assay (ELISA) to detect KHV antibodies. The assay was optimized with respect to plates, buffers, antigens and assay conditions. It demonstrated high diagnostic and analytical sensitivity and specificity and was particularly useful at the pond or farm levels. Considering the scale of the carp and koi industry worldwide, this assay represents an important practical tool for the indirect detection of KHV, also in the absence of clinical signs.
Up to now, the caryophyllid cestode Atractolytocestus huronensis Anthony, 1958, a parasite of common carp, has attracted little attention in Germany. Based on recent publications from the Czech ...Republic and Hungary, it appears probable that this cestode may be increasingly common in Germany. There is a strong connection between the occurrence of A. huronensis and imports of common carp from the Czech Republic and southern Germany. Although in most cases no clinical alterations in parasitized carp have been observed, care should be taken to avoid further dissemination and to prevent possible losses in commercial pond farming.
Using flow-microfluorometry analysis and cluster determinant (CD) markers, we studied how lymphocyte subpopulations in lymphoid organs of specific-pathogen-free pigs developed in pigs from birth to ...young adulthood. Cell suspensions of the thymus and spleen were prepared and peripheral blood cells were collected at 1, 4, 10, and 40 weeks of age. Tissue sections of the thymus and spleen were stained with monoclonal antibodies directed against CD2 and immunoglobulin to localize the CD2-Ig- lymphocyte subpopulation. In the thymus, only limited changes were observed in the lymphocyte subpopulations with time. Most thymocytes expressed CD4 or CD8 or both. Most CD2-Ig- cells or, 'null cells', (5-13%) were observed in the medulla of the thymus and probably represented a recirculating cell type. In the spleen and blood the percentage of CD2+ and Ig+ cells increased significantly with time, the former increasing from about 30-60% owing to an increase of CD8+ cells. Therefore, the selective increase of the CD8+ population also caused the CD4/CD8 ratio to change. Although CD2+ cells in the spleen and blood are positive for CD4 or CD8, but not for both, quantities of CD4+ CD8+ cells were also observed. Half of the lymphocytes in the spleen and blood were typed as null cells at 1 week of age and decreased in proportion to the increase of the CD8+ and Ig+ cells. Nevertheless, quantities of null cells were still present in the spleen blood at 40 weeks of age. Almost all these were located in the red pulp of the spleen. This study indicates an effect of age and housing conditions on the distribution of the lymphocyte subpopulations, and especially on the CD8+ subset. Quantities of CD4+CD8+ cells as well as CD4-CD8- were observed in blood, but also in spleen of pigs. The function of high numbers of null cells directly after birth are discussed.
Genetic variation in two harbour seal (Phoca vitulina) populations from the Dutch Wadden Sea and Scotland was examined by RAPD analysis and DNA fingerprinting. For comparison a population of grey ...seals (Halichoerus grypus) was studied. The RAPD method revealed a very low number of polymorphic bands. The multilocus DNA fingerprinting technique showed very low levels of variation both within and between populations of the harbour seals. For one probe a significant difference in variation between populations was demonstrated. The estimated average heterozygosity, however, diverged more strongly between the two harbour seal populations because of more frequent occurrence of rare alleles in the Scottish population. Low levels of genetic variation seem to be characteristic for the subspecies Phoca vitulina vitulina, but not for all marine mammals in the North Sea, as the grey seal population showed significantly higher variation.
The structure and amount of genetic variation within and between three subspecies of the harbour seal Phoca vitulina was assessed by multilocus DNA fingerprinting. Bandsharing similarity indicates ...that the subspecies Phoca vitulina richardsi (Alaska, East Pacific) is clearly separated from the other two subspecies, Phoca vitulina concolor (Sable Island, West Atlantic) and Phoca vitulina vitulina (North Sea, East Atlantic). The subspecies also differ significantly in the estimated amount of heterozygosity. Phoca vitulina richardsi has by far the highest amount of genetic variation, whereas P. vitulina vitulina has very low levels of genetic variation. Within the subspecies P. vitulina vitulina, especially the Wadden Sea population is depauperate of genetic variation. The findings are discussed in a historical, biogeographical and a conservation biological context.
An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. ...During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg
h
−1
m
−2 (30–60 ng
h
−1 per g dry plant––540–1080 ng
h
−1 per plant), in total. Limonene, α-thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (
M
S) and temperature coefficients were determined:
β
limonene=0.108 K
−1 and
M
S=14.57 μg
h
−1
m
−2;
β
sabinene=0.095 K
−1 and
M
S=5.39 μg
h
−1
m
−2.
The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.
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