Implications of conspecific background noise for features of blue tit, Cyanistes caeruleus , communication networks at dawn

Communication among animals often comprises several signallers and receivers within the signal’s transmission range. In such communication networks, individuals can extract information about differences in relative performance of conspecifics by eavesdropping on their signalling interactions. In songbirds, information can be encoded in the timing of signals, which either alternate or overlap, and both male and female receivers may utilise this information when engaging in territorial interactions or making reproductive decisions, respectively. We investigated how conspecific background noise at dawn may overlay and possibly constrain the perception of such singing patterns. We simulated a small communication network of blue tits, Cyanistes caeruleus, at dawn in spring. Two loudspeakers simulated a singing interaction which was recorded from four different receiver positions simulating potential eavesdroppers. During the recordings, resident blue tit males were vocalising and created natural conspecific background noise. Levels of conspecific background noise were high and varied among positions of potential eavesdroppers. We conclude that conspecific background vocalisations may potentially constrain the perception of singing patterns and may constitute costs for eavesdroppers. On the other hand, signallers may position themselves strategically and privatise their interactions.     

Schinzel acrocallosal syndrome: a variant example of the Greig syndrome?

A 5-month-old male is reported with clinical and radiological findings identical to those present in the Schinzel acrocallosal syndrome. The similarity with the Greig syndrome is discussed and the question is raised whether both syndromes are variant examples of the same autosomal dominant condition.     

Wheat cultivar reactions to deleterious rhizosphere bacteria under gnotobiotic conditions

With the aim of elucidating mechanisms behind bacteria-induced deleterious effects and differential cultivar responses to bacterial inoculations, wheat seedlings were subjected to various tests under gnotobiotic conditions. Inoculation with two deleterious Pseudomonas isolates, Å 112 (fluorescent) and Å 313 (nonfluorescent), induced leaf symptoms and shoot and root growth inhibition, while inoculation with growthneutral bacteria (Serratia liquefaciens andEscherichia coli) had no such effects. Deleterious effects were induced at low inoculum densities (<10³ cells per plant), but required addition of nutrient broth in small amounts for consistency. Effects similar to those obtained with living inoculum could be induced by treating plants with sterile culture filtrates from isolate Å 313 or volatile bacterial metabolites from isolate Å 112. Wheat cultivars previously found to differ in their reaction to inoculation under non-sterile conditions, responded differentially to Å 112 and Å 313 also in the gnotobiotic assay. The results agree with the hypothesis that neither cultivar reaction nor the bacterial effects as such are mediated by interactions with an indigenous rhizosphere microflora.     

A cDNA encoding a small common precursor for human pancreatic polypeptide and pancreatic icosapeptide.

A cDNA for the hormone, human pancreatic polypeptide (PP), was isolated by oligodeoxynucleotide screening from a cDNA library constructed from normal human pancreatic mRNA. The primary structure of the precursor protein as deduced from the cDNA sequence is 95 amino acids long and is composed of a typical, but rather long signal peptide of 29 residues, followed by the sequence of the 36 amino acid human pancreatic polypeptide, which again is separated from the human pancreatic icosapeptide sequence by a classic cleavage and amidation site, Gly-Lys-Arg. The precursor terminates in a heptapeptide which is cleaved from the icosapeptide at a monobasic processing site. Both the size and the structure of the PP precursor was supported by the results of peptide analysis of biosynthetically labeled pro-PP isolated from canine PP cells in which processing was prevented by the arginine analogue canavanine. It is concluded that the precursor for mammalian PP gives rise to two peptide products, the well preserved, carboxyamidated PP and an icosapeptide which is preserved only in its COOH-terminal end, plus a small highly variable COOH-terminal oligopeptide.     

Cardiac troponin I levels in canine pyometra

Background  

Myocardial injury may contribute to unexpected deaths due to pyometra. To detect myocardial damage, measurement of cardiac troponin I (cTnI) is currently the most sensitive and specific method. The aims of the present study were to evaluate presence of myocardial damage in canine pyometra by analysis of cTnI, to explore whether myocardial injury was associated with systemic inflammatory response syndrome (SIRS) and to evaluate whether other clinical or laboratory parameters were associated with cTnI increase.     

Visibility conditions and diel period affect small-scale spatio-temporal behaviour of pike Esox lucius in the absence of prey and conspecifics

Pike Esox lucius in the absence of prey and conspecifics were shown to have the highest habitat-change activity during dusk and to decrease preference for complex habitats in turbid water. As the behaviours indicate routine responses in the absence of behavioural interactions, E. lucius spatio-temporal distributions should be directly affected and thereby more easily assessed and avoided by prey, with potential consequences for encounter rates.     

High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues

Background  

In biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR) method for ex vivo angiography and to compare the findings with computed tomography (CT). To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle.     

Characteristics of a plant deleterious rhizosphere pseudomonad and its inhibitory metabolite(s)

A cell-free culture filtrate of the plant growth inhibitory bacterial isolate Å313, identified as Pseudomonas fluorescens, was tested for its effect on wheat root elongation in vitro, with and without various pretreatments. The filtrate showed a strongly inhibitory effect on root elongation and could be heated to 100°C for 5 min or incubated at a pH within the range of 4–10 without losing its activity. Unlike other root growth-inhibitory bacterial metabolites the effect of the filtrate was not reversed by methionine, nor was any inhibitory activity present in the water phase after extraction with chloroform. The inhibitory agent(s) was formed when the bacterium was grown in an artificial medium as well as in root exudates from wheat. Two wheat cultivars differing in reaction to inoculation with living cells of Å313 showed the expected difference in growth reduction when exposed to culture filtrate, indicating a cultivar difference in sensitivity to the metabolite(s) formed by the bacterium. Isolate Å313 invaded intercellular spaces of the root cortex of gnotobiotically grown wheat plants, but did not produce pectolytic enzymes in vitro, nor induce a hypersensitive response in tobacco plants.