An immunohistochemical study of canine disseminated aspergillosis

An immunohistochemical study of 25 lesions from 7 dogs with disseminated aspergillosis (Aspergillus terreus) is presented. All had multiple fungal granulomas in many viscera, with centres of necrotic tissue and hyphal elements surrounded by a mixed infiltrate of predominantly mononuclear cells. Within these lesions, hyphae coated with immunoglobulin (IgG, IgM, IgA) and complement (C3, C4) were identified, together with peri-lesional mononuclear cells that reacted with antisera directed towards either IgG, IgM, IgA or a T lymphocyte marker (MUII). A conspicuous feature was the prominent hyphal fluorescence seen with IgA and C3 antisera. The IgA reagent also marked large numbers of mononuclear cells both around lesions and scattered throughout interstitial tissue, suggesting an abnormality of IgA production or regulation as a factor predisposing to this condition.     

The pathogenesis of the nervous syndrome of Phalaris aquatica toxicity in sheep

The clinical signs displayed by 96 sheep affected by the nervous syndrome of Phalaris aquatica toxicity and 10 normal sheep injected intravenously with the phalaris alkaloid, 5-methoxy dimethyltryptamine (dose range 0.01 to 5.0 mg/kg), were observed. The distributions of phalaris indole-like cytoplasmic pigments in nuclei of the brains and spinal cords of 9 naturally affected sheep were determined microscopically. Based on the relationship between clinical signs and the central nervous system nuclei involved in their production, the distribution of phalaris indole-like pigments, and the pharmacology of dimethylated tryptamines, it is suggested that the nervous syndrome induced by Phalaris aquatica results from a direct action of phalaris alkaloids upon serotonergic receptors in specific brain and spinal cord nuclei.     

Effect of Cryopreservation on the Sperm DNA Fragmentation Dynamics of the Bottlenose Dolphin (Tursiops truncatus)

Sperm DNA fragmentation is one of the major causes of infertility; the sperm chromatin dispersion test (SCDt) evaluates this parameter and offers the advantage of species‐specific validated protocol and ease of use under field conditions. The main purpose of this study was to evaluate sperm DNA fragmentation dynamics in both fresh and post‐thaw bottlenose dolphin sperm using the SCDt following different cryopreservation protocols to gain new information about the post‐thaw differential sperm DNA longevity in this species. Fresh and cryopreserved semen samples from five bottlenose dolphins were examined for sperm DNA fragmentation dynamics using the SCDt (Halomax^®). Sperm DNA fragmentation was assessed immediately at collection and following cryopreservation (T0) and then after 0.5, 1, 4, 8, 24, 48 and 72 h incubation at 37°C. Serially collected ejaculates from four dolphins were frozen using different cryopreservation protocols in a TES‐TRIS‐fructose buffer (TTF), an egg‐yolk‐free vegetable lipid LP1 buffer (LP1) and human sperm preservation medium (HSPM). Fresh ejaculated spermatozoa initially showed low levels of DNA fragmentation for up to 48 h. Lower Sperm DNA fragmentation (SDF) was found in the second fresh ejaculate compared to the first when more than one sample was collected on the same day (p < 0.05); this difference was not apparent in any other seminal characteristic. While there was no difference observed in SDF between fresh and frozen–thawed sperm using the different cryopreservation protocols immediately after thawing (T0), frozen–thawed spermatozoa incubated at 37°C showed an increase in the rate of SDF after 24 h. Sperm frozen in the LP1^? buffer had higher levels (p < 0.05) of DNA fragmentation after 24‐ and 48‐h incubation than those frozen in TTF or HSPM. No correlation was found between any seminal characteristic and DNA fragmentation in either fresh and/or frozen–thawed samples.     

Aetiology of leaf spot of garlic and onion caused by Stemphylium vesicarium in Spain

Surveys between 1989 and 1993 in the major garlic production areas of Spain identified a new leaf spot disease, characterized by white and purple lesions followed by extensive necrosis. Isolation and pathogenicity tests with fungal isolates taken from these spots indicated that Stemphylium vesicarium was the causal agent. Pseudothecia of the teleomorph stage, Pleospora sp., were found on leaf debris from affected plants. Inoculation of garlic and onion plants with residues carrying mature pseudothecia, or with ascospore suspensions obtained from the pseudothecia, resulted in the development of white and purple leaf spots. Wetness periods longer than 24 h were required for symptom development under controlled conditions. Isolates of S. vesicarium from garlic, onion and asparagus caused disease in all three hosts. In garlic, cv. Blanco de Vallelado was most susceptible, while lines B4P17 and B6P1, and cvs Iberose and Golourose were less susceptible to the disease.     

The Solar Acoustic Spectrum and Eigenmode Parameters

The Global Oscillation Network Group (GONG) project estimates the frequencies, amplitudes, and linewidths of more than 250,000 acoustic resonances of the sun from data sets lasting 36 days. The frequency resolution of a single data set is 0.321 microhertz. For frequencies averaged over the azimuthal order m, the median formal error is 0.044 microhertz, and the associated median fractional error is 1.6 x 10(-5). For a 3-year data set, the fractional error is expected to be 3 x 10(-6). The GONG m-averaged frequency measurements differ from other helioseismic data sets by 0.03 to 0.08 microhertz. The differences arise from a combination of systematic errors, random errors, and possible changes in solar structure.     

Primary production of the biosphere: integrating terrestrial and oceanic components

Integrating conceptually similar models of the growth of marine and terrestrial primary producers yielded an estimated global net primary production (NPP) of 104.9 petagrams of carbon per year, with roughly equal contributions from land and oceans. Approaches based on satellite indices of absorbed solar radiation indicate marked heterogeneity in NPP for both land and oceans, reflecting the influence of physical and ecological processes. The spatial and temporal distributions of ocean NPP are consistent with primary limitation by light, nutrients, and temperature. On land, water limitation imposes additional constraints. On land and ocean, progressive changes in NPP can result in altered carbon storage, although contrasts in mechanisms of carbon storage and rates of organic matter turnover result in a range of relations between carbon storage and changes in NPP.