Phenology of cryptomonads and the CRY1 lineage in a coastal brackish lagoon (Vistula Lagoon,Baltic Sea)

Cryptomonadales have acquired their plastids by secondary endosymbiosis. A novel clade—CRY1—has been discovered at the base of the Cryptomonadales tree, but it remains unknown whether it contains plastids. Cryptomonadales are also an important component of phytoplankton assemblages. However, they cannot be readily identified in fixed samples, and knowledge on dynamics and distribution of specific taxa is scarce. We investigated the phenology of the CRY1 lineage, three cryptomonadales clades and a species Proteomonas sulcata in a brackish lagoon of the Baltic Sea (salinity 0.3–3.9) using fluorescence in situ hybridization. A newly design probe revealed that specimens of the CRY1 lineage were aplastidic. This adds evidence against the chromalveolate hypothesis, and suggests that the evolution of cryptomonadales’ plastids might have been shorter than is currently assumed. The CRY1 lineage was the most abundant cryptomonad clade in the lagoon. All of the studied cryptomonads peaked in spring at the most freshwater station, except for P. sulcata that peaked in summer and autumn. Salinity and concentration of dissolved inorganic nitrogen most significantly affected their distribution and dynamics. Our findings contribute to the ecology and evolution of cryptomonads, and may advance understanding of evolutionary relationships within the eukaryotic tree of life.     

Novel DNA-binding element within the C-terminal extension of the nuclear receptor DNA-binding domain

The heterodimer of the ecdysone receptor (EcR) and ultraspiracle (Usp), members of the nuclear receptors superfamily, is considered as the functional receptor for ecdysteroids initiating molting and metamorphosis in insects. Here we report the 1.95Å structure of the complex formed by the DNA-binding domains (DBDs) the EcR and the Usp, bound to the natural pseudopalindromic response element. Comparison of the structure with that obtained previously, using an idealized response element, shows how the EcRDBD, which has been previously reported to possess extraordinary flexibility, accommodates DNA-induced structural changes. Part of the C-terminal extension (CTE) of the EcRDBD folds into an α-helix whose location in the minor groove does not match any of the locations previously observed for nuclear receptors. Mutational analyses suggest that the α-helix is a component of EcR-box, a novel element indispensable for DNA-binding and located within the nuclear receptor CTE. This element seems to be a general feature of all known EcRs.     

Evaluation of Mineral Concentrations in Maternal Serum Before and After Birth and in Newborn Cord Blood Postpartum—Preliminary Study

The mineral levels in maternal serum change during pregnancy and may be correlated with those of newborn cord blood. The aim of this study was to evaluate the concentrations of calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), and copper (Cu) in maternal blood before and after delivery and in umbilical cord vein and artery serum. The study was carried out in 64 Caucasian pregnant women who delivered in a district hospital in Greater Poland region, aged 28.1 ± 5.4 years, with a mean gestational age of 39.2 ± 1.3 weeks. Blood samples were taken from women 2–8 h before delivery and immediately after childbirth. The umbilical cord artery and vein blood of newborns was obtained immediately after childbirth. The levels of minerals in serum were determined by flame atomic absorption spectrometry. A significant drop in the concentrations of Mg (17.71 ± 1.51 vs 17.07 ± 1.61 μg/ml; p < 0.007), Fe (1.08 ± 0.46 vs 0.82 ± 0.35 μg/ml; p < 0.0004), and Zn (0.63 ± 0.17 vs 0.46 ± 0.16; p < 0.0001) in maternal serum was found after delivery. Moreover, higher levels of Ca, Fe, and Zn and lower levels of Cu were observed in the umbilical vein (Ca: 102.80 ± 7.80 μg/ml; p < 0.0001, Fe: 1.96 ± 0.43 μg/ml; p < 0.0001, Zn: 0.65 ± 0.16 μg/ml; p < 0.0001, Cu: 0.36 ± 0.09 μg/ml; p < 0.0001) and in the umbilical artery cord blood (Ca: 98.07 ± 8.18 μg/ml; p < 0.0001, Fe: 1.63 ± 0.30 μg/ml; p < 0.0001, Zn: 0.65 ± 0.15 μg/ml; p < 0.0001, and Cu: 0.36 ± 0.10 μg/ml; p < 0.0001) compared to the maternal serum (Ca: 85.05 ± 10.76 μg/ml, Fe: 0.82 ± 0.35 μg/ml, Zn: 0.46 ± 0.16 μg/ml, and Cu: 1.90 ± 0.35 μg/ml). Fe levels in the cord artery serum negatively correlated with blood loss during delivery (R = ?0.48; p = 0.01), while the Ca concentration in the maternal serum after birth decreased with the age of the women (R = ?0.25; p = 0.03). In conclusion, it seems that the process of birth alters the mineral levels in pregnant women’s blood. Moreover, it was found that blood loss and the age of the mother are associated with mineral concentrations in the maternal serum and cord artery blood.     

Clearance of chicken cystatin from the rat circulation

Chicken cystatin (mixed form) was prepared from egg white. Radioactively labeled preparations were administered intravenously to rats. ¹²⁵I-cystatin disappeared from the rat circulation with a half-life of -73 min. The radiolabeled inhibitor was rapidly taken up by the kidneys. Percoll density gradient analysis showed that it was incorporated into lysosomes. Within 24 hr after the injection of ¹²⁵I-cystatin, 25% of the administered radioactivity was recovered in the urine, but only 2% was in the protein-bound form.     

Insertion of peptide chains into lipid membranes: An off-lattice Monte Carlo dynamics model

A combination of dynamic Monte Carlo simulation techniques with a hydropathy scale method for the prediction of the location of transmembrane fragments in membrane proteins is described. The new hydropathy scale proposed here is based on experimental data for the interactions of tripeptides with phospholipid membranes (Jacobs, R.E., White, S.H. Biochemistry 26:6127–6134, 1987) and the self-solvation effect in protein systems (Roseman, M.A., J. Mol. Biol. 200:513–522, 1988). The simulations give good predictions both for the state of association and the orientation of the peptide relative to the membrane surface of a number of peptides including Magainin2, M2δ, and melittin. Furthermore, for Pf1 bacterio-phage coat protein, in accord with experiment, the simulations predict that the C-terminus forms a transmembrane helix and the N-terminus forms a helix which is adsorbed on the surface of the bilayer. Finally, the present series of simulations provide a number of insights into the mechanism of insertion of peptides into cell membranes. © 1993 Wiley-Liss, Inc.     

Influence of temperature on the growth and survivability of sichel larvae Pelecus cultratus reared under controlled conditions

Ichthyological Research - This study analyzed the influence of temperature on the rearing of sichel Pelecus cultratus larvae under controlled conditions. Five constant temperature regimes were...     

Structural aspects of L-asparaginases, their friends and relations

Enzymes capable of converting L-asparagine to L-aspartate can be classified as bacterial-type or plant-type L-asparaginases. Bacterial-type L-asparaginases are further divided into subtypes I and II, defined by their intra-/extra-cellular localization, substrate affinity, and oligomeric form. Plant-type L-asparaginases are evolutionarily and structurally distinct from the bacterial-type enzymes. They function as potassium-dependent or -independent Ntn-hydrolases, similar to the well characterized aspartylglucosaminidases with (alphabeta)2 oligomeric structure. The review discusses the structural aspects of both types of L-asparaginases and highlights some peculiarities of their catalytic mechanisms. The bacterial-type enzymes are believed to have a disordered active site which gets properly organized on substrate binding. The plant-type enzymes, which are more active as isoaspartyl aminopeptidases, pose a chemical challenge common to other Ntn-hydrolases, which is how an N-terminal nucleophile can activate itself or cleave its own alpha-amide bond before the activation is even possible. The K+ -independent plant-type L-asparaginases show an unusual sodium coordination by main-chain carbonyl groups and have a key arginine residue which by sensing the arrangement at the oligomeric (alphabeta)-(alphabeta) interface is able to discriminate among substrates presented for hydrolysis.     

Neuroendocrine tumors of gastrointestinal tract in own material

Neuroendocrine tumors are rare gastrointestinal tract disorders, in which diagnosis and treatment are often difficult. The aim of the paper is to present two cases of patients with neuroendocrine tumor of gastrointestinal tract, who underwent surgical procedure in II Department of General and Gastroenterological Surgery of Medical University of Bia?ystok in 2005. A 63-year-old female patient with primary diagnosis of neuroendicrine tumor metastases in liver was not successfully investigated for primary tumor in the preoperative period. The laparotomy procedure indicated the malignant neuroendocrine tumor in the terminal ileum and metastases to the liver and to the greater omentum. The right hemicolectomy and liver metastatic segment VII and VIII resection were performed. The neurological disturbances of obscure origin were observed in the postoperative period and the patient suddenly died on the 15(th) day after surgery. A 57-years-old male patient was operated on for lymph node recurrence of gastric tumor. Pathologic examination of tissue sample revealed the diagnosis of carcinoid. The patient underwent subtotal gastric resection for a pyloric ulcer, diagnosed as Adenocarcinoma G2 pT2N0M0 6 years before. Liver and abdominal node metastases, confirmed by octreoscan, were observed after lymphadenectomy, The treatment of somatostatin analogues (LAR octreotide) was used. In spite of therapy the patient died. The authors present their own experiences and show the preoperative diagnostic difficulties in patients with neuroendocrine gastrointestinal tumors. Unexpected neurological complications in the treatment course were described.