Correcting eggshell indices of raptor eggs for hole size and eccentricity

Eggshell thickness is often expressed by means of an index based on the length, breadth and weight of the shell. The effect of the blow-hole and egg eccentricity on Ratcliffe's shell thickness index was investigated in a sample of 585 eggs from six raptor species. Corrections for the size of the hole and egg eccentricity are proposed, as is a combined formula to correct both sources of error at the same time. It is shown that by using these formulae, considerable improvements in estimates of shell thinning are obtained. These may be especially useful when sample sizes are small, which is often the case when working with species that have been reduced in numbers.     

Magnetic Dynabeads detection by sensitive element based on giant magnetoimpedance

A GMI-biosensor prototype was designed and fabricated using an amorphous ribbon. As a first step, a GMI response was measured with a model liquid media: suspension containing magnetisable Dynabeads M-450. These beads can be used as biomolecular labels when coated with a specific antibody. The GMI change caused by their presence was measured with a biosensor prototype designed with a measuring cell containing an amorphous CoFeMoSiB-ribbon element. GMI was measured at a range of current frequencies from 0.3 to 10 MHz and at intensities of either Irms=3 or 4.5 mA. Commercial Dynabeads M-450 were supplied as a suspension in a phosphate buffered saline. A maximum difference of 25% in the GMI ratio measured with and without Dynabeads was obtained at a frequency of 3.5 MHz and Irms=3 mA. Some potential applications for GMI-biosensor and further directions are proposed.     

At home among strangers: Alfred Russel Wallace in Russia

Alfred Russel Wallace (1823–1913) was an influential figure within Russian pre-Synthetic evolutionary biology, i.e. the time period before the Synthetic Theory of Evolution was established (ca. 1880–1930s). His major works were translated into Russian and his general ideas were read and discussed by both insiders and outsiders of scientific evolutionism. At the same time, Wallace played a controversial role in the growth of Darwinism in Russia, and Charles Robert Darwin (1809–1882) has eclipsed Wallace in his influence on Russian evolutionary thinking. In this paper we briefly outline Wallace’s impact on Russian pre-Synthetic scientific evolutionism and its general intellectual climate. We demonstrate that both Russian pro-Darwinian evolutionists and anti-Darwinians (scientific anti-Darwinians as well as creationists) were fully aware of Wallace’s contributions to the development of evolutionary theory. Yet, Wallace’s radical selectionism, as well as his controversial arguments for “design in nature”, predetermined his special place within the Russian intellectual landscape.     

150 Jahre Mendel

The monk and his legacy: 150 years of Mendel The paper demonstrates how the experiments of Gregor Johann Mendel (1822–1884) with plant hybrids in the late 1860s revolutionized modern biology. It also shows how the commemoration of his anniversaries during the 20th century reflected the change of scientific epochs determined by the growth of genetics and related fields.     

Bias Assessment of General Chemistry Analytes using Commutable Samples

Harmonisation of reference intervals for routine general chemistry analytes has been a goal for many years. Analytical bias may prevent this harmonisation. To determine if analytical bias is present when comparing methods, the use of commutable samples, or samples that have the same properties as the clinical samples routinely analysed, should be used as reference samples to eliminate the possibility of matrix effect. The use of commutable samples has improved the identification of unacceptable analytical performance in the Netherlands and Spain. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has undertaken a pilot study using commutable samples in an attempt to determine not only country specific reference intervals but to make them comparable between countries. Australia and New Zealand, through the Australasian Association of Clinical Biochemists (AACB), have also undertaken an assessment of analytical bias using commutable samples and determined that of the 27 general chemistry analytes studied, 19 showed sufficiently small between method biases as to not prevent harmonisation of reference intervals. Application of evidence based approaches including the determination of analytical bias using commutable material is necessary when seeking to harmonise reference intervals.     

Signal transduction: hair brains in bacterial chemotaxis

The conserved cytoplasmic domains of bacterial chemotaxis receptors are a fibrous arrangement of alpha-helical coiled coils that look a lot like hair. Such bundles of alpha-helical filaments mediate sensory-motor responses in all prokaryotic cells. How do they work? Very nearly perfectly is probably as good an answer as any.     

Armin von Tschermak-Seysenegg (1870–1952): Physiologist and Co-‘Rediscoverer’ of Mendel’s laws

The ‘rediscovery’ of Mendel’s laws in 1900 was a turning point in modern research of heredity/genetics. According to the traditional view, adopted and fostered by many textbooks of genetics, Mendel’s principles were presented in the first half of 1900 simultaneously and independently by three biologists (H. de Vries, C. Correns, E. v. Tschermak-Seysenegg). Having thus laid the foundations of further development, the ‘rediscovery’ continues to attract considerable interest. Since the 1950s, however, serious questions arose concerning both the chronology and specific conceptual achievement of the scientists involved. Not only the independence but also parallelism was analysed in the context of individual research programmes of these three scholars. The youngest of them, Erich v. Tschermak-Seysenegg, was even excluded from the list of ‘rediscoverers’. The aim of this paper is to use new archival evidence and approximate the contribution of the physiologist and ophthalmologist Armin von Tschermak-Seysenegg (1870–1952) to the events of 1900 and 1901.     

Monoclonal antibodies against chicken type V collagen: production, specificity, and use for immunocytochemical localization in embryonic cornea and other organs

Two monoclonal antibodies have been produced against chick type V collagen and shown to be highly specific for separate, conformational dependent determinants within this molecule. When used for immunocytochemical tissue localization, these antibodies show that a major site for the in situ deposition of type V is within the extracellular matrices of many dense connective tissues. In these, however, it is largely in a form unavailable to the antibodies, thus requiring a specific “unmasking” treatment to obtain successful immunocytochemical staining. The specificity of these two IgG antibodies was determined by inhibition ELISA, in which only type V and no other known collagen shows inhibition. In ELISA, mixtures of the two antibodies give an additive binding reaction to the collagen, suggesting that each is against a different antigenic determinant. That both antigenic determinants are conformational dependent, being either in, or closely associated with, the collagen helix is demonstrated by the loss of antibody binding to molecules that have been thermally denatured. The temperature at which this occurs, as assayed by inhibition ELISA, is very similar to that at which the collagen helix melts, as determined by optical rotation. This gives strong additional evidence that the antibodies are directed against the collagen. The antibodies were used for indirect immunofluorescence analyses of cryostat sections of corneas and other organs from 17 to 18-day-old chick embryos. Of all tissues examined only Bowman’s membrane gave a strong staining reaction with cryostat sections of unfixed material. Staining in other areas of the cornea and in other tissues was very light or nonexistent. When, however, sections were pretreated with pepsin dissolved in dilute HAc or, surprisingly, with the dilute HAc itself dramatic new staining by the antibodies was observed in most tissues examined. The staining, which was specific for the anti-type V collagen antibodies, was largely confined to extracellular matrices of dense connective tissues. Experiments using protease inhibitors suggested that the “unmasking” did not involve proteolysis. We do not yet know the mechanism of this unmasking; however, one possibility is that the dilute acid causes swelling or conformational changes in a type-V collagen-containing supramolecular structure. Further studies should allow us to determine whether this is the case.