Structural comparison of the 68 kDa laminin-binding protein and 5'-nucleotidase from chicken muscular sources: evidence against a gross structural similarity of both proteins

The 68 kDa laminin-binding protein purified from chicken skeletal muscle and the ectoenzyme 5'-nucleotidase from chicken gizzard are both able to interact with laminin. They were both shown to possess a nearly identical amino acid composition. The 79 kDa glycosylated form of 5'-nucleotidase can be transformed into an enzymatically active form by treatment with endoglycosidase F (Endo F). Deglycosylated (Endo F-treated) 5'-nucleotidase exhibits an apparent molecular mass of 68 kDa. Using immunological and finger-printing techniques, both proteins were analysed to determine their structural relatedness. The results obtained indicate that both proteins are not identical but may posses a few common peptides of yet unknown sequence and length.     

The heat generated by yeast cultures with a mixed metabolism in the transition between respiration and fermentation

The heat generated by both batch and continuous cultures of the yeast K. fragilis was studied using a modified Bench Scale Calorimeter. Batch cultures were used to measure the heat dissipation rates and the heat yields during fully aerobic and completely anaerobic growth, whereas continuous cultures enabled, in addition, a quantitative study of heat dissipation rates during growth on mixed metabolism. In this case, the extent of fermentation versus respiration could be specified and controlled by varying the degree of oxygen limitation. The heat dissipated per unit biomass formed was highest for fully respirative catabolism and fell continuously to a much lower value typical of anaerobic cultures as the catabolism was shifted increasingly to the fermentative mode. The heat generated per mole of oxygen taken up stayed quite close to the fully aerobic value of 506 kJ mol(-1) even when a sizable fraction of the substrate available to catabolism was fermented. If the fraction of respiration in the metabolism is lowered beyond a certain threshold, the ratio of the heat generation to oxygen consumption starts to increase dramatically and finally tends to infinity for fully anaerobic growth. All experimental results were quantitatively analyzed and explained on the basis of a simple model which formally describes the cultures in terms of two parallel "chemical" reactions. In simple cases such as the one presented here, the model enables calculation of the whole stoichiometry of the culture from a single measured heat yield.     

Cell attachment properties of collagen type VI and arg-gly-asp dependent binding to its α2(VI) and α3(VI) chains

Twelve of sixteen different cell types including fibroblasts and tumor cells were able to attach and spread on substrates of pepsin-solubilized or intact collagen VI, and on its triple helical domain. Attachment and spreading were independent of soluble mediator proteins (fibronectin, laminin) and collagen VI was distinct from collagens I, IV and V in the cells with which it interacted. Many of the same cells bound and spread on substrates prepared from unfolded α2(VI) and α3(VI) chains but not on the α1(VI) chain. The interactions with the chains were inhibited by low concentrations (10–100 μM) of synthetic RGDS and RGDT but not RGES peptides while the binding of cells to pepsin-solubilized collagen VI was more than 20-fold less sensitive to these peptides. The data incidate that cells have the ability to bind to collagen VI in a specific manner suggesting a similar function for collagen VI in situ.     

Brutbiologie des Turmfalken (Falco tinnunculus): 16j?hrige Untersuchungen in Westfalen

Zusammenfassung Anhand einer 16jährigen Untersuchung im Raum Ostwestfalen/Bielefeld wird der Bruterfolg des Turmfalken anhand von 439 Gelegen und 2256 Eiern beschrieben. Drei Brutplatztypen können unterschieden werden: A. Baumbruten in Nestern; B₁. Baumbruten in Nistkästen; B₂. Gebäudebruten in Nischen oder Nistkästen. Zwischen Baumbruten (A) und Nistkastenbruten (B_1/2) werden signifikante Unterschiede beschrieben, die für Nistkästen größere Gelege (ca. ein Ei mehr) und größeren Ausfliegeerfolg belegen. Zwischen Nistkästen in Bäumen (B₁) oder an Gebäuden (B₂) konnten keine signifikanten Unterschiede festgestellt werden. Weiterhin werden Lege- und Schlupftermine, Legerhythmus und oologische Daten aus dem Untersuchungsgebiet angegeben.

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Breeding biology of Kestrels (Falco tinnunculus) in Eastern Westfalia 1972–1987

Summary The 16 years of study gave 439 clutches with 2,256 eggs. We separated three types of breeding sites: the use of (a) stick nests, mostly built by corvids (cf. Tab., Fig. 3), (b₁) nest boxes attached to trees or telegraph poles (Fig. 2) and (b₂) nest boxes or cavities at or in buildings (Fig. 1). Within these different types of breeding places we found some significant differences. Stick nests had less eggs and though less breeding success, which was possibly caused by predation of corvids, especially magpies. Within the two types of places with nest boxes no significant differences could be established. We concluded, that stick nests were marginal in Kestrels and nest boxes were optimal despite of their placement in trees, at poles or in buildings. Furthermore, the timing of breeding cycle was described (Fig. 4) and laying interval was determind to an average value of approximately two days (Fig. 5). Mean egg size was and average volume 21.2 cm². Two daily controlled clutches lost 15.5% and 16.1% of mass (Fig. 6) pressumably mostly due to water losses.

     

Sequence differences between glycosylated and non-glycosylated Asn-X-Thr/Ser acceptor sites: implications for protein engineering

In N-glycosylated glycoproteins, carbohydrate is attached to Asn in the sequence Asn-X-Ser/Thr, where X denotes any amino acid. However, the presence of this consensus peptide does not always lead to glycosylation. We have compiled an extensive collection of glycosylated and non-glycosylated Asn-X-Thr/Ser sites and present a statistical study based on this data set. Our results indicate that non-glycosylated sites tend to be found more frequently towards the C termini of glycoproteins, and that proline residues in positions X and Y in the consensus Asn-X-Thr/Ser-Y strongly reduce the likelihood of N-linked glycosylation. Beyond this, there are no obvious local sequence features that seem to correlate with the absence or presence of N-linked glycosylation. These findings are discussed in terms of the prediction and engineering of glycosylation sites in secretory proteins.     

Cleavage-site motifs in mitochondrial targeting peptides

Although mitochondrial targeting peptides lack a common consensus sequence, a certain bias in the positional distribution of amino acids has recently been found. These patterns seem to be associated with cleavage of the precursor proteins by matrix processing proteases. We have extended the previous studies and found new sequence motifs that are conserved within subgroups of mitochondrial targeting peptides. These motifs have certain common themes, indicating that they are associated with cleavage by one single protease. Two of the conserved patterns have a high predictive value, but even for sequences that do not possess these patterns, a fairly accurate prediction of the cleavage site is shown to be possible. We also suggest that a well-conserved RXY decreases (S/A) pattern may be used to engineer efficiently recognized cleavage sites into uncleaved or artificial mitochondrial targeting peptides.     

Mannose 6-phosphate/insulin-like growth factor II-binding proteins in human serum and urine. Their relation to the mannose 6-phosphate/insulin-like growth factor II receptor.

Human serum and urine contain polypeptides which bind mannose 6-phosphate (M6P) and insulin-like growth factor II (IGF II) and crossreact with antibodies against the M6P/IGF II receptor. These polypeptides are considered to be fragments of the M6P/IGF II receptor. The major Mr approx. 205,000 fragment in serum and urine is about 10 kDa smaller in size than the membrane-associated receptor and is accompanied by minor forms with Mr values ranging from 104,000 to 180,000. The presence of receptor fragments in biological fluids indicates that shedding is one of the mechanisms contributing to the turnover of the M6P/IGF II receptor and that receptor fragments are part of the heterogenous group of serum proteins whic bind IGF II.     

Neonatal screening for congenital adrenal hyperplasia using 17-hydroxyprogesterone assay in filter paper blood spots

Screening of infants for congenital adrenal hyperplasia (CAH) using filter paper blood samples collected on the 5th day of life was performed with a radioimmunoassay for 17-hydroxyprogesterone without extraction with organic solvents. A total of 153,000 newborns were screened and 12 cases of CAH were detected (1:12,800). With recall levels related to gestational age, the recall rate could be lowered to 0.05%.