Volatile compounds of selected strawberry varieties analyzed by purge-and-trap headspace GC-MS

Six strawberry (Fragaria x ananassa Duch.) varieties, Senga Sengana, Jonsok, Polka, Korona, Bounty, and Honeoye, were studied in relation to composition of their volatile headspace compounds collected by dynamic purge-and-trap concentration. Also, the influence of cultivation technique on the volatile compounds was tested by comparing conventionally and organically cultivated strawberry varieties. In addition, the effect of geographical origin on strawberry volatiles was investigated. The emphasis of this study was lay in the industrial utilization of strawberry. A total of 52 different volatile compounds were determined from frozen strawberries grown in 1997 and 1998. In addition to individual compounds, total areas of chromatogram profiles were compared. The major esters were found to be methyl butanoate, ethyl butanoate, methyl hexanoate, and ethyl hexanoate. With the application of principal component analysis and analysis of variance to the data matrix, the varieties were classified into three groups. Var. Honeoye was most different from the others. Organic cultivation had no effect on strawberry volatiles.     

Pulmonary edema in a dog with acute pancreatitis and cardiac disease

Acute pancreatitis and cardiac disease were diagnosed in a dog with pulmonary edema. The early clinical course and initial thoracic radiographs suggested that the pulmonary edema was noncardiogenic. The late clinical course was complicated by heart failure. The dog died, and a necropsy was performed. Histologically, an acute, severe capillary-alveolar membrane lesion was found in the lungs. Review of the human medical literature indicated that respiratory complications, including pulmonary edema, are commonly recognized in people with acute pancreatitis. Furthermore, in acute pancreatitis of human beings, the existence of specific mechanisms of pulmonary injury is suspected. Retrospective consideration of this case suggested that the initial pulmonary edema was induced by acute pancreatitis.     

The fermentative capacity of growing pigs and adult sows fed diets with contrasting type and level of dietary fibre

Adult sows have a more developed gastro-intestinal system than young growing pigs resulting in a superior capacity to digest fibrous components. The main objective of this study was to describe the capacity of sows and growing pigs to digest the fibre components in concentrated low dietary fibre (DF) diet and two high DF diets similar in DF but with contrasting DF solubility. Six sows and four growing pigs were fitted with a simple T-cannula at the terminal ileum. Each balance experiment consisted of a 7-day initial period followed by a 3-day collection of faeces and a 2 or 3-day collection of ileal digesta for growing pigs and adult sows, respectively. When feeding diets with high proportions of soluble non-starch polysaccharides (NSP), the difference in fermentation capacity between growing pigs and adult sows was small. The adult sows showed a higher fermentative capacity, evidenced by a higher fermentation and a higher methane production, when high fibre diet with high amount of insoluble fibre was fed.     

Effects of wood char and activated carbon on the hydrolysis of cellobiose by β-glucosidase from Aspergillus niger

Biochar amendments to soils have been suggested as a strategy to sequester carbon and therefore mitigate global climate change. The enrichment of soils with charred materials also increases their fertility. This fertilising effect of biochar may be caused by various mechanisms; an acceleration of nutrient cycling has been suggested as one such mechanism. The rate-limiting step in nutrient cycling is thought to be the extracellular enzymatic attack on biological macromolecules. In this study, therefore, the effects of chestnut wood char (specific surface area 2.0 m² g⁻¹) and of activated carbon (specific surface area approximately 900 m² g⁻¹) on an extracellular enzymatic reaction involved in the degradation of cellulose (i.e., hydrolysis of cellobiose by β-glucosidase from Aspergillus niger) were investigated. Cellobiose was not adsorbed by chestnut wood char, whereas activated carbon absorbed more than 97% of it. Both charred materials adsorbed more than 99% of β-glucosidase. For chestnut wood char, adsorption of the enzyme caused a decrease of approximately 30% in the reaction rate, whereas for activated carbon, the nearly complete absorption of both substrate and enzyme entirely inhibited the reaction. These results show that β-glucosidase from A. niger retains most of its activity when adsorbed to chestnut wood char and that the reaction it catalyses in nature is only slightly affected by this charred material. On the other hand, a material characterised by a high specific surface area and high porosity, such as activated carbon, can make even a highly soluble substrate unavailable for soil enzymes and therefore completely inhibit the reaction. Thus, charred materials may affect nutrient cycling mainly by regulating the availability of substrates: the degradation of highly soluble substrates may be accelerated by materials with low specific surface area, which maintain an active and protected enzyme pool, whereas materials with high specific surface and high porosity may slow down the degradation by making substrates unavailable.     

Artificial infection of Vaccinium vitis-idaea L. and defence responses to Exobasidium species

An inoculation method for Exobasidium splendidum and Exobasidium vaccinii was developed on the dwarf shrub Vaccinium vitis-idaea. Using inoculated ramets, we investigated whether there are differences between V. vitis-idaea populations in the susceptibility to Exobasidium infections and whether the defence reaction of V. vitis-idaea is visible at a molecular level. Sixteen V. vitis-idaea clones from four populations were propagated in tissue cultures and the ramets were inoculated with E. splendidum or E. vaccinii fungi. The expression of three flavonoid biosynthetic genes (chalcone synthase, dihydroflavonol 4-reductase and anthocyanidin synthase) and the accumulation of flavonoids and hydroxycinnamic acids were determined in response to E. splendidum infection. A pathogenesis-related (PR 4) gene was isolated and its expression was studied in host ramet leaves. To our knowledge, this was the first successful artificial infection reported with E. splendidum. Disease frequencies of the inoculated ramets were between 32% and 47% for E. splendidum and 33% for E. vaccinii, but below 10% in uninoculated control ramets. There were no differences in disease frequencies between V. vitis-idaea populations. Both symptomatic leaves and healthy leaves of diseased ramets showed activation of flavonoid biosynthesis at the gene level, whereas expression of PR 4 was observed only in symptomatic leaves. The increase of flavonoid biosynthesis in healthy leaves of diseased ramets may represent a general response to stress or a role in defence against the pathogen E. splendidium. Ability of V. vitis-idaea to defend chemically against Exobasidium fungi and the heterogeneity of genotypes, age, size, and growth rates in host plant populations might be reasons for the low infection incidence of Exobasidia in nature.     

<Emphasis Type="Italic">Eimeria bovis</Emphasis> meront I-carrying host cells express parasite-specific antigens on their surface membrane

Host immune responses conducted against antigens of Eimeria bovis are key factors for the development of protective immunity against this protozoan disease. In this study we investigated the expression of E. bovis-derived antigens on the host cell surface membrane during E. bovis first merogony in vitro. Host cells carrying E. bovis-meront I stages expressed E. bovis host cell surface antigens (EbHCSAg) on their surface membrane which were recognised by hyperimmune sera of calves and by sera from rats immunized with E. bovis merozoites I, when tested by indirect immune fluorescent antibody test (IIFAT), laser scanning confocal microscopy (LSCM) and immune electron microscopy. Expression of EbHCSAg on permissive host cells was earliest detected 7 days p. i., thus coinciding with the onset of the parasite replication. Membrane-associated EbHCSAg were removed from infected host cells by proteinase K, partially by Triton X-100, Triton X-114 and Triton X-405, but not by 1 M NaCl, CHAPS or phospholipase C treatment. Antibodies, affinity-purified on paraformaldehyde/glutardialdehyde (PAGA)-fixed E. bovis meront I-infected bovine host cells bound to the surface meront I-carrying cells and to merozoites I (IIFAT, LSCM) but, in contrast to untreated sera, not to sporozoites. When tested on methanol-fixed merozoites I and sporozoites by IIFAT, affinity-purified antibodies bound to structures in the apical complex area of merozoites I, but not to sporozoites, whilst untreated sera caused diffuse labelling of internal structures of both parasite stages. Immune electron microscopy demonstrated binding of affinity-purified antibodies to micronemes and dense granules of merozoites I. Although the function of EbHCSAg is still unknown, results of this study might suggest an involvement in the development of protective immunity against E. bovis infections.