World Congress of Malacology Antwerp ... - Unitas Malacologica

GST/S-crystallins are enzymatically inactive, except for one without an insert peptide. Ω-crystallin, a
minor cephalopod crystallin, descended from aldehyde dehydrogenase (ALDH) and lacks enzyme
activity. Scallop lenses lack S-crystallins and accumulate inactive Ω-crystallin (ScΩ-crystallin;
ALDH1A9). Cytoplasmic ScΩ-crystallin aligns best with mitochondrial ALDH2 but lacks a
mitochondrial N-terminal signal sequence. ScΩ-crystallin does not bind NAD(P) possibly due to I to
V modifications at positions 278 and 282. ScΩ-crystallin comprises 4 ~50 kilodalton subunits, yet,
unlike ALDH2, chromatographs as a ~100 kilodalton protein. The ScΩ-crystallin promoter, like other
crystallin promoters, contains transcription factor binding sites for Maf, CRE, Retinoic acid receptor
and Pax. Crystallin promoters utilize Pax6 for all species tested except jellyfish, which use PaxB
containing a Pax2/5/8 paired domain. The ScΩ-crystallin promoter has two putative Pax binding sites
that can interact with Pax6. Site 2, however, has a 3’ C consistent with preferential binding by Pax2.
Possibly then the ScΩ-crystallin gene is activated by Pax6 and/or Pax2 (both are present in scallops).
Thus, mollusc crystallins evolved from GST and ALDH by convergent events employing gene
duplication, profound changes in promoter activity, and multiple alterations in protein structure.
Adverse effects of the Zebra mussel (Dreissena polymorpha) on the Swollen river mussel (Unio
tumidus) in a riverine habitat
Piechocki, Andrzej
Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Banacha 12/16, 90-237
Lodz, Poland
Email: andrzej.piechocki1@neostrada.pl
The study was carried out in a mid-forest part of the Wielki Kanał Brdy (River Brda Great Canal)
downstream of the village of Rytel in the Tucholskie Forest (NW Poland). The canal section sampled
is 20 - 30 m wide and 0.5-1.5 m deep; the bottom is sandy-gravelly. The most common molluscs in
the samples included Viviparus viviparus, Dreissena polymorpha, and unionids, represented
primarily by Unio tumidus.
All the U. tumidus individuals collected were covered by clumps of zebra mussel, the density of the
latter varying from 2 to 44 individuals per unionid (mean of 15,2). In most cases, the total weight of
the zebra mussel exceeded that of the swollen river mussel and ranged from 0,9 to 30,9 g (mean of
10, 1 g). The zebra mussel to the infested mussel weight ratio was 0,2 – 6,8 (mean of 2,4 g). The
zebra mussel shells measured. 5,0 – 23,6 mm; most of the D. polymorpha individuals being adults.
The observations showed the zebra mussel to negatively affect the swollen river mussel. The adverse
effects were manifested as a small size of the infested U. tumidus (mean shell length of 39, 1 mm),
thinning and perforation of their shells, and increased mortality. A 15.1-20.0 g zebra mussel load per
unionid was found to constitute a critical level marking the beginning of U. tumidus die-off. Dead
individuals accounted for 35.2 % of the population studied, their proportion being much higher than
that in river and lakes free of D. polymorpha.
Molecular characteristics of the part of Na,K-ATPase alpha subunit isolated
from Helix pomatia L.
Pienkowska, Joanna; Lesicki, Andrzej
Department of Cell Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland,
Email: pienkowj@amu.edu.pl; alesicki@amu.edu.pl
The Na,K-ATPase, or a sodium pump, belongs to the very important family of enzymes mediating
the ATP-dependent transport of Na + and K + ions against their electrochemical gradients across the
plasma membrane. All animal cells have a sodium pump, which is crucial to various physiological
processes, including osmoregulation, cell volume regulation, transport of certain amino acids and
sugars, and maintenance of membrane excitability. Na,K-ATPase is composed of two noncovalently
linked subunits: Na,K-α (catalytic subunit) and Na,K-β (subunit required for the translation,
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