Matrix Gla protein C-terminal region binds to vitronectin. Co-localization suggests binding occurs during tissue development.

Matrix Gla protein (MGP) regulates calcification in cartilage and arteries. MGP synthesis during embryonic development and its binding and regulation of growth factors and morphogens of the TGF-beta/BMP superfamily suggests that it has additional functions. Assay by far-western gel overlays and gel filtration shift shows MGP binds vitronectin. Binding is saturable and consistent with a single class of binding sites. MGP binds to vitronectin but not collagen, fibromodulin, heparin, osteocalcin, chondroitin sulfate, laminin, ovalbumin or albumin. We have identified a vitronectin binding site within a 17-amino acid peptide 61-77 near the carboxyl-terminus that corresponds to a naturally occurring MGP C-terminus. MGP and the 61-77 MGP peptide also binds to fibronectin. MGP and vitronectin are focally co-localized in embryonic tissues. Co-localization in vivo suggests that the MGP and vitronectin interactions may modify cell-matrix interactions. Alternatively, vitronectin-bound MGP may have altered function for modulating BMP2 or TGF-beta activity. The current study demonstrates that MGP has a novel binding activity for vitronectin, an extracellular protein that promotes cell-matrix interactions and regulates coagulation.     

Ruddy turnstones Arenaria interpres rapidly build pectoral muscle after raptor scares

To cope with changes in the environment, organisms not only show behavioural but also phenotypic adjustments. This is well established for the digestive tract. Here we present a first case of birds adjusting their flight machinery in response to predation risk. In an indoor experiment, ruddy turnstones Arenaria interpres were subjected to an unpredictable daily appearance of either a raptor or a small gull (as a control). Ruddy turnstones experiencing threat induced by a flying raptor model, longer than after similar passage by the gull model, refrained from feeding after this disturbance. Pectoral muscle mass, but not lean mass, responded in a course of a few days to changes in the perceived threat of predation. Pectoral muscle mass increased after raptor scares. Taking the small increases in body mass into account, pectoral muscle mass was 3.6% higher than aerodynamically predicted for constant flight performance. This demonstrates that perceived risk factors may directly affect organ size.     

Purification and characterization of a hemagglutinin isolated from the leaves of Chenopodium (Chenopodium amaranticolor).

A hemagglutinin was isolated and purified from the leaves of Chenopodium (Chenopodium amaranticolor) using ion-exchange chromatography and affinity chromatography on fetuin-agarose matrix. It agglutinated rabbit erythrocytes. The hemagglutinin had a native molecular mass of 58 kDa, as estimated by gel filtration and showed a single band of molecular mass of 33 kDa on SDS-PAGE. It showed hemagglutination activity over the pH range 3-12 and was found to be stable up to 70 degrees C. On isoelectrofocussing, the pI of this hemagglutinin was estimated to be 5.25. However, it was found to contain seven charge variants when isoelectrofocussing was performed in presence of 6M urea.     

Aspects of the feeding habits and reproductive biology of the Ghana mole-rat Cryptomys zechi (Rodentia, Bathyergidae)

The feeding habits and reproductive biology of the Ghana mole‐rat, Cryptomys zechi (Matchie), were studied in a Guinea savanna woodland in Ghana. Both tunnel contents and stomach content analysis indicated that bulbs and tubers constituted the commonest and most preferred food items, although some animal food materials were also consumed. Five plant species, Urgenia altissima, Manihot utilisima, Curuligo sp., Oxalis corniculata and Archis hypogea, were the most popular plant food source. Breeding occurred during the rainy season (March–August) and was at its peak in July. There is evidence that the species is capable of producing two litters in a year. In a colony, reproduction is restricted to one female and one male. Males reached sexual maturity at a lower body weights (105 g) than females (155 g). Estimated mean litter size was 1.5 (range 1–2), the smallest among the bathergids. Available data on birth weights of three other species of social Cryptomys indicate that C. zechi has the highest birth weight, which is comparable to that of solitary bathyergids.     

Haemophilus influenzae antibiotic resistant strains isolated in Moscow in 2002-2004]

The results of 3-year observation on emergence of H. influenzae antibiotic resistant strains in Moscow are summarized. The study included 566 strains isolated from patients in 2002-2004. The susceptibility was determined by the 2-fold microdilution method on the Haemophilus test medium. The percentage of the resistant strains isolated in 2002, 2003 and 2004 was the following: ampicillin --4.9, 3.2 and 3.6%, tetracycline--3.3, 3.2 and 1.8% and co-trimoxazole--10.9, 20.9 and 20% respectively. The strains isolated in 2003 and 2004 were resistant to azithromycin in 0.6 and 1.8% of the isolates and to clarithromycin in 1.3 and 3.2% of the isolates respectively. Five isolates differed by the minimum resistance to ampicillin whereas producing no beta-lactamase (BLNAR strains). The drugs of choice for the treatment of respiratory tract infections mainly due to H. influenzae, i.e. acute otitis and sinusitis, chronic bronchitis exacerbation and sometimes pneumonia remain betalactam antibiotics. From the microbiological viewpoint the inhibitor-protected aminopenicillins, cefuroxime and cefotaxime have no significant advantages vs. amoxycillin. The use of cotrimoxazole and chloramphenicol should be considered inexpedient.     

Fine structural recognition specificities of IgE antibodies distinguishing amoxicilloyl and amoxicillanyl determinants in allergic subjects.

IgE antibodies in the sera of subjects allergic to beta-lactam antibiotics detect a spectrum of specificities ranging from side-chain groups to an entire penicillin or cephalosporin molecule. In addition to such structural heterogeneity of allergenic determinants, IgE antibodies in the sera of different allergic subjects show heterogeneous recognition responses. Detailed immunochemical studies were carried out on the sera of penicillin-allergic subjects that showed selective and unexpected reactions with the frequently prescribed penicillin, amoxicillin. Antibodies from one subject reacted only with the amoxicilloyl determinant while IgE from another subject showed multiple reactivity with penicilloyl and penicillanyl determinants of different penicillins but not with the amoxicilloyl determinant. Quantitative hapten inhibition studies revealed that the combining sites of the former antibodies were complementary to amoxicillin in a form that permits binding to the hydroxyaminobenzyl side-chain and the thiazolidine ring carboxyl. These conditions are satisfied with the drug in the '-oyl' but not in the '-anyl' form which involves linkage through the 2-carboxyl of the thiazolidine ring. With the second serum, adsorption studies showed that the wide-ranging reactivity of IgE was due to a single population of antibodies that detected a common specificity on the different penicillins. Combining site studies revealed clear recognition of the benzyl portion of the side-chain of benzylpenicilloyl, benzylpenicillanyl, ampicilloyl, ampicillanyl and amoxicillanyl determinants when free antibody access to the side-chain was possible but little or no recognition of the ring hydroxyl of amoxicillin. Such uninhibited access may not occur, however, when amoxicillin is conjugated in the '-oyl' form since opening the beta-lactam ring allows increased flexibility and rotation of the molecule and the possibility of close association of the hydroxyaminobenzyl side-chain of amoxicillin with the linked peptide carrier. In such close steric association, H-bonding involving the ring hydroxyl and amino acids of the carrier may prevent antibody access to the side-chain region of the amoxicilloyl determinant.     

Specific targeting of insect and vertebrate telomeres with pyrrole and imidazole polyamides.

DNA minor groove-binding compounds (polyamides) that target insect and vertebrate telomeric repeats with high specificity were synthesized. Base pair recognition of these polyamides is based on the presence of the heterocyclic amino acids pyrrole and imidazole. One compound (TH52B) interacts uniquely and with excellent specificity (K(d) = 0.12 nM) with two consecutive insect-type telomeric repeats (TTAGG). A related compound, TH59, displays high specificity (K(d) = 0.5 nM) for tandem vertebrate (TTAGGG) and insect telomeric repeats. The high affinity and specificity of these compounds were achieved by bidentate binding of two flexibly linked DNA-binding moieties. Epifluorescence microscopy studies show that fluorescent derivatives of TH52B and TH59 stain insect or vertebrate telomeres of chromosomes and nuclei sharply. Importantly, the telomere-specific polyamide signals of HeLa chromosomes co-localize with the immunofluorescence signals of the telomere-binding protein TRF1. Our results demonstrate that telomere-specific compounds allow rapid estimation of relative telomere length. The insect-specific compound TH52 was shown to be incorporated rapidly into growing Sf9 cells, underlining the potential of these compounds for telomere biology and possibly human medicine.     

Frost Injury as a Possible Inciting Factor in Bud and Shoot Necroses of Fraxinus excelsior L.

Large numbers of European ash have died in Poland in all age classes during the last ten years. The characteristic symptom occurring on shoots of planted and self‐sown seedlings was bark necroses starting from the shoot apex, necrotic buds, or leaf and twig scars. The results showed that in the bud tissue of cold acclimated European ash extracellular and intracellular ice formation occurred at approximately ?9 and ?32°C, respectively. In deacclimated plants in spring water supercooling is limited by the heterogenous ice nucleation temperature and consequently the cold tolerance is ?9 to ?4°C for bud tissues and ?13 to ?9°C for shoots. Isolations of fungi were performed from dead buds and from necroses occurring on the main stem. Alternaria alternata, Fusarium lateritium and Phomopsis scobina were among the fungi occurring in both these organs at frequencies of more than 7%. Cylindrocarpon heteronemum, Diplodia mutila and Tubercularia vulgaris from necroses were only isolated in frequencies; 3.3, 1.2 and 5.4%, respectively. It seems likely that freezing injury is the inciting factor, which combined with fungal colonization manifests itself as fatal damage to European ash buds and shoots.