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1

Lysozyme-like activity in eggs and in some tissues of land snails Helix aspersa maxima and Achatina achatina

100%

Fiolka M. J., Witkowski A.

Folia Biologica

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2004

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vol. 52

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issue 3-4

233-237

EN

Antibacterial lysozyme-like activity against Micrococcus luteus in eggs and some tissues of snails Helix aspers maxima and Achatina achatina was detected in a turbidimetric standard assay. The bacteriolytic activity in Helix aspersa maxima was higher than in Achatina achatina. After the application of the bioautography technique, several lytic zones of Micrococcus luteus were observed in both studied species. Electrophoresis in denaturing conditions followed by immunodetection of lysozyme using EWL antibodies indicated the presence of several lysozyme forms in the tested snails.

2

Laying characteristics of one- and twoyear old pheasants (Phasianus colchicus, L.)

100%

Krystianiak S., Kontecka H., Nowaczewski S., Rosinski A.

Folia Biologica

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2007

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vol. 55

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issue 1-2

65-72

EN

The aim of the study was to assess laying traits, the weight of eggs and characters of the laying rhythm of pheasants in the first and second years of reproduction. Pheasants (10 cockerels and 50 hens) were kept in aviaries. Daily, individual control of laying was performed beginning with the day of the first laying and ending with the last egg. The following parameters were evaluated: age at first laying, length of the laying period, number of laid eggs and the average weight of the egg in the 8th week of laying. The laying rhythm was also assessed and comprised: the number of egg clutches, the number of eggs in a clutch, the number of eggs in the longest clutch, the number of intervals, the length of intervals and the longest interval between clutches. During the first period of reproduction, in comparison with the second, pheasants laid slightly more eggs of similar average weight. The first laying period was longer than the second and was characterised by a greater number of egg clutches and greater number of intervals between clutches. The greatest number of eggs was laid in 10-egg and longer clutches, although the 1-egg clutches were the most numerous. A positive correlation was found between the number of eggs and the number of clutches, the greatest number of eggs in a clutch and the number of intervals between clutches. The similar values of the reproductive characters of one- and two-year old pheasants point to the possibility of longer utilization of these birds than only for one laying period. On the other hand, the considerable variability between the experimental hens with regard to the number and the length of egg clutches, as well as the intervals between them, indicate the possibility to carry out selection taking into account traits characterising the laying rhythm.

3

Observations on embryogenesis of Notothenia neglecta Nybelin in Admiralty Bay (King George Island, South Shetland Islands, Antarctica)

100%

Sapota M. R.

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4

Predetermination of cytokinesis and transition from holoblastic to partial superficial cleavage in early embryonic development of Tetrodontophora bielanensis (Collembola)

88%

Klag J., Krzysztofowicz A., Jura C., Kisiel E.

Folia Biologica

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2000

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vol. 48

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issue 3-4

137-142

EN

In the T. bielanensis embryo, only karyokinesis occurs during the first cleavage division, and a two-nuclear syncytial embryo forms. Then, two cytoplasmic concentrations in the form of elongated rolls perpendicular to each other develop below the periplasm at the animal pole of the egg. The second cleavage division is also associated with karyokineses only. After the embryo reaches the four-nuclear stage, cytokineses occur at its animal pole, and two cleavage furrows perpendicular to each other develop in the periplasm above the cytoplasmic concentrations. The cell membranes forming within the furrows do not invade the cytoplasmic concentrations, but their growing tips push them into the egg interior, where they merge and form the central cytoplasmic concentration. The developing cell membranes do not invade the central cytoplasm; they band and grow above its surface. Four pyramidal blastomeres form as a result of this. The eight-blastomere embryo forms through both karyokinesis and cytokinesis, but the growing cell membranes now band below the previous ones and cut off anucleate parts of the mother blastomeres, which fuse with the central cytoplasm. Thus, during this phase of development the transition from holoblastic to partial superficial cleavage is initiated. Morphological analysis suggests that the formation of the first two cytokineses is predetermined by and depends on factors connected with the animal pole periplasm. It also suggests that the central cytoplasm constitutes the morphological field, inducing the transition from holoblastic to partial superficial cleavage.

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Lysozyme-like activity in eggs and in some tissues of land snails Helix aspersa maxima and Achatina achatina

Laying characteristics of one- and twoyear old pheasants (Phasianus colchicus, L.)

Observations on embryogenesis of Notothenia neglecta Nybelin in Admiralty Bay (King George Island, South Shetland Islands, Antarctica)

Predetermination of cytokinesis and transition from holoblastic to partial superficial cleavage in early embryonic development of Tetrodontophora bielanensis (Collembola)