Months Of Preservation Research Articles

The use of an electric freezer in human semen banking

The use of an electric freezer for cryostorage of human semen is described. A simple method for semen freezing in liquid nitrogen after dilution with 7.5% glycerol was used. Thawing for quality analysis revealed only a small decrease (10%) in post-thaw sperm motility (59 ± 1.4 vs. 53 ± 1.8%; mean ± SE, n = 12, P < 10 −5) and 14% in post-thaw sperm vitality (85.0 ± 1.3 vs. 72.9 ± 1.8%). After the freezing process, the samples, three of each donor, were cryopreserved in a regular electric freezer which maintained temperatures in the range of −85 °C (±2 °C). The samples were stored for 1 week, 2 and 6 months, thawed and then assayed for motility and vitality. No effect of storage was found for a period up to 2 months. An additional decrease of 17.2% in sperm motility and 18% in sperm vitality were noted only after 6 months of preservation. The final motility and vitality rates of these sperm samples were 44 ± 2.4 and 60 ± 3.0%, respectively. According to these results, in cases of sperm storage for limited periods, it is recommended to cryopreserve human semen by the use of a combination of freezing in liquid nitrogen and storage of the samples in an electric freezer at −85 °C.

Bacterial Canker of Sweet Cherry (Prunus avium) in Poland

AbstractIn Polish climatic conditions cherry cankers resulting from infection by Pseudomonas morsprunorum continue development in summer, but the rate may be slower than in the period from April to June.However, from the well established, active canker developing under the dwarf shoot of the susceptible variety‘Hedelfińska’in July no P. morsprunorum were isolated. On the other hand, numerous strains of the genus Erwinia were found there which caused a hyper sensitivity reaction (HR) on tobacco leaves. From the cracks on the current‐year cherry shoots, due to fresh infection and from symptomless leaves P. morsprunorum strains were isolated, always accompanied by those of the Erwinia genus in the approximate proportion 1: 1 or 1:2.The strains of Erwinia genus seemed similar to the DC and YC strains isolated by BILLING and BAKER from pear and apple trees infected by fireblight and also to the strains in group III of the bacteria isolated by CROSSE from cherry leaves.In two tests (immediately after isolation and after 4 months of storage) the strains of the Erwinia genus and 3 nonidentified isolates induced HR. At a third test, after 10 months of preservation these strains were HR‐negative in contrast to the P. morsprunorum isolates.The fact that strains of the Erwinia genus inducing HR were isolated in large numbers from active cherry canker where pathogenic bacteria were not detected, may indicate that they play some role in the development of cherry tree canker.

Apercu Sur L'Action Des Procedes De Conservation Sur La Biomasse D'Organismes Micronectoniques Et Macroplanctoniques

Sixty-eight micronekton and macroplankton samples collected with a 3 m Isaacs-Kidd Midwater Trawl were preserved with ten percent buffered formaldehyde solution. An investigation of wet weight loss was carried out over a period of 7 months. The loss varies according to the material and reached 45% of the live weight with gelatinous organisms. A few samples were frozen in seawater at a temperature of −20°C. The weight loss subsequent to thawing reached higher percentages than with preservation in formaldehyde. Dry weight determinations have been made for a few samples. Wet weight loss subsequent to preservation and freezing seems to be directly related to the water content of organisms. It is recommended not to estimate biomass before several months of preservation.