Nutrient responses to the liming of lake Gårdsjön

The acidified lakes Lake Gårdsjön and Lake Stora Hästevatten the reference lake have been monitored since 1979 and 1980 respectively. The lakes are situated in SW Sweden; in an area severly affected by acid deposition. Lake Gårdsjön was limed in spring 1982. This paper analyses changes in nutrient concentrations upon liming of Lake Gårdsjön. The liming of Lake Gårdsjön was followed by a slight increase in ammonium, nitrate, and dissolved organic nitrogen concentrations. A drastic decrease occurred in particulate nitrogen and particulate carbon, whereas dissolved organic carbon increased. Total phosphorus and particulate phosphorus concentrations were similar to pre-limed conditions. The long-term decrease in phosphorus concentration, exhibited by the reference lake, was not identified in Lake Gårdsjön after liming, but total phosphorus concentration was still less than half compared to Lake Gårdsjön in the early 1970's. Additional measures such as phosphorus fertilization, should in certain cases be considered in addition to liming if the goal is to restore lakes to their pre-acidic conditions.     

An association between a lymphocyte antigen in sheep and the response to vaccination against the parasite Trichostrongylus colubriformis

Lymphocyte antigens were tested in sheep which had been selected for responsiveness to vaccination against the intestinal nematode Trichostrongylus colubriformis. These sheep had been bred in an assortative mating programme which produced offspring designated as either “high responders” or “low responders”, with highly heritable resistance or susceptibility.Ovine lymphocyte antigen (OLA) typing antisera were obtained from parous ewes in the course of matings which produced the high and low responder flocks. A particular antigen (SY1) was found to be present in high frequency on the lymphocytes of high responder (72·2%) and in lower frequency (21·9%) on the lymphocytes of low responder rams. In ewes, the frequency for high responders was 65·7% and for low responders it was 33·5%. A similar association between the SY1 antigen and low faecal egg count was found in random-bred sheep which had been vaccinated with irradiated larvae and challenged with normal larvae. The conclusion was drawn that this lymphocyte antigen was likely to be part of the sheep major histocompatibility complex which influenced the immune response of sheep to vaccination against the parasite.     

Preparation of capacitor’s electrode from sunflower seed shell

Series of nanoporous carbons are prepared from sunflower seed shell (SSS) by two different strategies and used as electrode material for electrochemical double-layer capacitor (EDLC). The surface area and pore-structure of the nanoporous carbons are characterized intensively using N₂ adsorption technique. The results show that the pore-structure of the carbons is closely related to activation temperature and dosage of KOH. Electrochemical measurements show that the carbons made by impregnation-activation process have better capacitive behavior and higher capacitance retention ratio at high drain current than the carbons made by carbonization-activation process, which is due to that there are abundant macroscopic pores and less interior micropore surface in the texture of the former. More importantly, the capacitive performances of these carbons are much better than ordered mesoporous carbons and commercial wood-based active carbon, thus highlighting the success of preparing high performance electrode material for EDLC from SSS.     

Development of sporeless/low sporing strains of Pleurotus through mutation

Summary The sporophores of Pleurotus are gymnocarpous and continuously release spores in the atmosphere causing respiratory allergies like hay fever and farmer’s lung disease among workers. The allergy is caused by the antigens present on the walls of the spores. Apart from this, during commercial production, these spores settle on the fruit bodies, germinate and form a velvety film which gives an unpleasant appearance to the mushrooms. The spores emitted may include new genotypes likely to attack wood or trees. Spore allergy is one of the most important limiting factors for the large scale cultivation of this species. Different approaches are being adopted at IIHR for the production of commercial sporeless/low-sporing strains of Pleurotus to alleviate the spore allergy problem. Attempts were made during the present investigation to produce sporeless or low-sporing mutants through u.v. mutation. Mutation of the mycelium did not yield the desired results. Mutation of the spores of Pleurotus sajor-caju yielded an extremely low-sporing mutant after 75 min exposure. The character has been found to be stable for more than 10 generations of subculturing.     

Aging-related changes in the sensitivity of the system of respiratory control and the intensity of free-radical processes in humans

Results of a comparative study of the sensitivity of the system of respiratory control to increases in the CO₂ concentration and the intensity of free-radical processes in young and elderly subjects are described. It is shown that normal (natural) aging is accompanied by a decrease in the sensitivity of the respiratory system to hypercapnic stimulation and a parallel significant decrease in the activity of catalase in the blood of examined subjects. Mechanisms responsible for the modifications of the sensitivity of the system of respiratory control to hypercapnia are discussed; these shifts can be at least partly related to changes in the intensity of production of free radicals observed in elderly subjects. Neirofiziologiya/Neurophysiology, Vol. 40, No. 1, pp. 53–57, January–February, 2008.