Determination of the polymorphic composition of smooth pea starch

A method for estimating the proportions of ‘A’ and ‘B’ polymorphs comprising a sample of ‘C’ type starch is proposed which uses established experimental techniques with commercially available spreadsheet and X-ray analysis software. Waxy maize, potato and smooth pea starches were used to provide X-ray diffraction patterns characteristic of the ‘A’, ‘B’ and ‘C’ starch polymorphs. Samples of amorphous starches were also prepared. The method initially involved subtraction of the amorphous phase and instrumental background from the X-ray diffraction patterns of each starch sample using the spreadsheet program, Lotus 1-2-3. The remainder of the pattern, representing the crystalline portion of the starch sample, was then analysed by profile fitting to elucidate the positions and areas of individual diffraction peaks. The ratio of the total peak area to the areas under peaks characteristic of ‘A’ and ‘B’ type starches, respectively, were used to calculate the relative proportions of these polymorphs in smooth pea starch. These proportions were found to be 56±3% ‘A’ polymorph to 44±3% ‘B’ polymorph. A ‘C’ type pattern was constructed by using Lotus 1-2-3 to combine diffraction patterns from the crystalline portions of ‘A’ and ‘B’ type starches in the proportions given above. Polymorph patterns were obtained by manipulation of the diffraction patterns from the crystalline portions of starches using Lotus 1-2-3. An ‘A’ type pattern was obtained by subtraction of a ‘B’ type pattern from that of a ‘C’ type. Similarly, a ‘B’ type pattern was obtained by subtraction of an ‘A’ type pattern from that of a ‘C’ type.     

Biosynthesis of Hb in individual fetal liver bursts : γ-Chain production peaks earlier than β-chain in the erythropoietic pathway

The relative synthesis of α-, β-, ^Gγ- and ^Aγ-globin chains has been evaluated in single fetal liver bursts, which were grown in methylcellulose cultures, individually labelled with [³H]leucine and then analysed via iso-electric focusing. Well-hemoglobinized bursts demonstrate a homogeneous globin synthetic pattern, characterized by prevalent HbF (+some HbA) synthesis: thus, they apparently originate from a homogeneously programmed population of erythroid burst-forming unit (BFU-E). On day 8–9 of culture, the synthetic pattern in ‘mature’ (i.e., well-hemoglobinized) bursts has been compared with that in simultaneously-grown, ‘immature’ (i.e., poorly-hemoglobinized) colonies. These patterns have been further compared with that in ‘matured’ bursts (identified in situ as immature on day 8–9 and labelled 2–4 days later when matured). The ‘immature’ colonies showed very low levels of relative β-globin synthesis, while the ‘mature’ ones demonstrated a more elevated production of β-chain. Significantly, the ‘matured’ bursts showed a globin chain synthetic pattern similar to that of previously labelled ‘matured’ colonies. It is postulated therefore that in fetal liver (and also in adult marrow) the synthesis of γ-chain is linked to an early differentiation stage of erythroblasts, while β-globin synthesis is largely activated at a more advanced maturation stage.     

Effect of epiphytes on the extent of necrotic injuries of resistant and susceptible poplar clones infected with Dothichiza populea.

Poplar cuttings of a resistant clone, Populus ‘Grandis’, and susceptible clones, Populus nigra ‘Italica’ and Populus ‘Robusta’, were infected with the pathogenic fungus Dothichiza populea alone, or with the pathogen and one of five strains of epiphytes antagonistic towards it (in vitro), isolated from poplar bark. The extent of injury was examined for 28 days after infection by determining the length of necrotic patches and their area as expressed in per cent of the total area of a cutting or the area of necrotic injuries caused by the pathogen alone.

All the poplar cuttings of both the resistant and susceptible clones became diseased when infected with the pathogen alone. Surprisingly enough, however, the least affected clone was the susceptible P. ‘Robusta’, in which necrotic injuries covered 28% of the total area, as against 40% and 70% in the resistant P. ‘Grandis’ and the susceptible P. nigra ‘Italica’, respectively.

When the cuttings were infected simultaneously with Dothichiza populea and its antagonistic epiphytes, the diseased area in the resistant clone diminished by as much as two-thirds, and in the susceptible P. nigra ‘Italica’, by one-third in comparison with the area affected by the pathogen alone. In turn, in the susceptible P. ‘Robusta’ the introduction of three out of five epiphytes stimulated the growth of the pathogenic fungus producing on average a double increase in the necrotic area. The differences in the response of the pathogen to the presence of epiphytes recorded in the susceptible clones indicate a marked influence of the plant on the nature of interactions between its epiphytic microflora and the pathogen.     

Ultrastructure of meristematic cells of dormant and released buds in Tradescantia paludosa

The lateral bud meristems of Tradescantia paludosa show a characteristic cytohistological zonation during dormancy. The cells comprising this so called ‘zone of inhibition’, which is located at the extreme tip of the bud apex, rarely synthesize nuclear DNA or undergo mitotic division. These nuclei are as large as prophase nuclei, yet contain only telophase (2C) amounts of DNA and significantly lower amounts of histone as compared to the 2C nuclei of the actively dividing cells.Ultrastructural observations of the nuclei in the ‘zone of inhibition’ show that a large proportion of the chromatin is organized as less condensed, diffuse, euchromatin fibrils; however, the chromatin of the actively dividing nuclei of the cells outside the ‘zone of inhibition’ or in the released bud meristems is organized to a greater extent as condensed clumps of heterochromatin. When the dormancy is released, the nuclei in the ‘zone of inhibition’ synthesize DNA and histone and undergo cell division in approx. 4 days. Striking changes in the organization of chromatin fibrils take place during this transition period. The diffuse chromatin fibrils of the nuclei in the ‘zone of inhibition’ progressively become more and more condensed as the cell prepares to undergo the first mitotic division after the release of dormancy. This change which is coupled with the synthesis of histones in the nuclei of the ‘zone of inhibition’ suggests a prominent structural role of these basic proteins in the organization of the chromatin. The large volume of 2C nuclei of the ‘zone of inhibition’ seems, therefore, to result not from a great nuclear mass, but probably from a relatively small degree of condensation of chromatin.     

Double infection experiments with echinostomatids (Trematoda) in Lymnaea stagnalis by implantation of rediae and exposure to miracidia

1972. Double infection experiments with echinostomatids (Trematoda) in Lymnaea stagnalis by implantation of rediae and exposure to miracidia. International Journal for Parasitology, 2: 409–423. Echinostomatid species parasitizing Lymnaea stagnalis as first intermediate hosts in a South German Lake have been found present in natural double infections, but at frequencies lower than expected. Simultaneous double infection and superinfection experiments in Lymnaea stagnalis with Isthmiophora melis, Echinoparyphium aconiatum and Echinostoma revolutum were performed by redial implantation and by exposure to miracidia. All three combinations possible of these echinostomatids proved to be unstable, one species being eliminated by another ‘stronger’ one after an invariable suppression order. The degree of vigour of Isthmiophora melis in this suppression order is greater if mother rediae (macropharyngeate) are present, i.e. after miracidial invasion instead of daughter redial implantation. Snails parasitized by rediae of a ‘weak’ type could be superinfected by implantation of rediae of a ‘strong’ type, but not if the first (‘weak’) infection had reached the stage of shedding cercariae. Superinfection by implantation of Echinoparyphium aconiatum rediae (‘strong’ type) was not successful when the first infection consisted of sporocysts of plagiorchiids, or of Apatemon sp. (Strigeidae) that had reached the stage of shedding cercariae.     

Historical review: another 50th anniversary--new periodicities in coiled coils

In 1953, Francis Crick and Linus Pauling both proposed models of supercoiled helices (‘coiled coils’) for the structure of keratin. These were the first attempts at modelling the tertiary structure of a protein. Crick emphasized the packing mode of the side-chains (‘knobs-into-holes’), which required a periodicity of seven residues over two helical turns (7/2) and a supercoil in the opposite sense of the constituent helices. By contrast, Pauling envisaged a broader set of periodicities (4/1, 7/2, 18/5, 15/4, 11/3) and supercoils of both senses. Crick's model became canonical and the ‘heptad repeat’ essentially synonymous with coiled coils, but 50 years later new crystal structures and protein sequences show that the less common periodicities envisaged by Pauling also occur in coiled coils, adding a variant packing mode (‘knobs-to-knobs’) to the standard model. Pauling's laboratory notebooks suggest that he searched unsuccessfully for this packing mode in 1953.     

A characteristic pharmacological action of ‘Yang-invigorating’ Chinese tonifying herbs: Enhancement of myocardial ATP-generation capacity

In order to investigate the pharmacological basis of ‘Yang-invigorating’ action, the effect of oral treatment with the methanolic extract of ‘Yang-invigorating’ herbs on ATP-generation capacity was examined, using heart homogenates prepared from herb-pretreated mice. Tonifying (i.e., health-promoting) herbs of other functional categories were also included for comparison. The results indicated that ‘Yang-invigorating’ Chinese tonifying herbs could invariably enhance myocardial ATP-generation capacity, with the extent of stimulation varying among the herbs. In contrast, ‘Yin-nourishing’ herbs either did not stimulate or even decreased myocardial ATP-generation capacity. While ‘Qi-invigorating’ herbs produced variable effects on myocardial ATP-generation capacity, most of the ‘blood-enriching’ herbs did not cause any significant changes. The results obtained from studies using myocardial mitochondrial fractions isolated from herb-pretreated mice suggest that ‘Yang-invigorating’ herbs might speed up ATP generation by increasing mitochondrial electron transport. The ensemble of results has provided evidence for the first time to support the pharmacological basis of ‘Yang invigoration’ in Chinese medicine.     

Catalase-positive particles (“microperoxisomes”) from rat preputial gland and bovine adrenal cortex

Catalase activity was detected histochemically within membrane-bound cell organelles in epithelial cells of rat preputial gland and bovine adrenal cortex. These particles are oval to worm-like in rat preputial gland, 0.08 – 0.15 μm thick and up to 1.0 μm long. In bovine adrenal cortex the shape of catalase-positive particles is rather spherical (diameter 0.1 to 0.3 μm). Particles of both organs lack crystalline or dense cores.Biochemical examination of cell fractions prepared from tissue homogenates by differential centrifugation revealed the presence of two typical peroxisomal oxidases, viz. α-hydroxy acid and -amino acid oxidase, with maximal relative specific activities in the ‘microsomal’ fraction (preputial gland) and in the ‘lysosomal’ fraction (adrenal cortex), respectively. Urate oxidase is absent in both tissues.The concomitant occurrence of catalase and hydrogen peroxide producing oxidases in the particles described characterizes them as true peroxisomal systems (‘microperoxisomes’).     

Isolation of autofluorescent ‘aged’ human fibroblasts by flow sorting : Morphology, enzyme activity and proliferative capacity

In cultures of human fibroblasts the percentage of bright autofluorescent (AF) cells increases with increasing passage number. These autofluorescent cells were isolated using a FACS II cell sorter and compared with sorted non-fluorescent (NF) cells. The AF cells showed an increase in population doubling time (2.3-fold), cell protein (1.9-fold), and in specific activities of the lysosomal enzymes: β-hexosaminidase (4.2-fold), β-galactosidase (3.8-fold) and acid phosphatase (2.5-fold). The specific activities of two non-lysosomal enzymes glucose-6-phosphate dehydrogenase and lactate dehydrogenase had increased only slightly (1.1-fold) respectively (1.5-fold).The autofluorescence in the AF cells was restricted to small round organelles. The distribution and size of these autofluorescence granules were similar to the acid phosphatase-containing granules in the cytochemically stained cells. Electronmicroscopical examination showed that these AF cells contained a large amount of small electron-dense granules containing amorphosmophilic material. These granules which were positive for the acid phosphatase reaction, were classified as secondary lysosomes. The low percentage of the sorted AF cells which incorporate [³H]thymidine during a 24 h test period (19%) as compared with the labelling percentage of sorted NF cells (73%) from the same culture, indicate that the autofluorescent cells in a ‘young’ culture have a very limited remaining proliferative capacity. The results imply, that by flow sorting it is possible to isolate ‘aged’ cells with characteristics of ‘phase III’ cells out of non-aged fibroblast cultures.     

The response of young Romney lambs to immunization with Trichostrongylus colubriformis larvae

1988. The response of young Romney lambs to immunization with Trichostrongylus colubriformis larvae. International Journal for Parasitology 18: 1035–1038. Groups of weaned Romney ewe lambs were immunized with two doses of 28,000, 35,000 or 42,000 (2000 kg⁻¹) infective larvae of Trichostrongylus colubriformis at 8, 12 or 16 weeks of age, respectively. Each group and helminthfree control lambs of similar age were challenged with T. colubriformis at the same dose rate as used for immunization. Faecal egg counts (FEC) and haematological observations were made during the experiment, and at slaughter, 42 days after challenge, worm burdens were determined and small intestinal histology was examined.

Lambs in each immunized group were identified as ‘responders’ or ‘non-responders’ on the basis of both FEC and worm burdens. A significant (P<0.001) decrease in the worm burdens recovered as a proportion of the challenge infections in both unimmunized and immunized lambs with increasing age was observed.

Globule leukocyte numbers increased with the age of lambs. In addition, within each age group globule leukocyte numbers reflected individual responsiveness to immunization, significantly (P<0.01) greater numbers being present in ‘responders’ than ‘non-responders’ or unimmunized lambs. No difference in haematological responses were found in relation to the lambs' responsiveness to immunization.     

Sequence dependent hydration of DNA

The transitions between the different helical conformations of DNA depend on the base sequence and the ambient conditions such as humidity and counter-ion concentration. In this study energy minimization techniques have been used to locate water molecule sites around nucleotides especially those which form hydrogen bonds between two or more nucleotide atoms and thus form solvent mediated bridges. We have studied several sequences and find that those which are known not to exist in the low hydration ‘A’ form have very similar number of bridging sites in both ‘A’ and ‘B’ conformations. Those sequences which are found in the ‘A’ conformation have considerably more bridging sites in this low hydration form than in the ‘B’ conformation. Sequence related solvent effects for a given conformation have also been analysed.     

Quantification of high-frequency sea-level fluctuations in shallow-water carbonates: an example from the Berriasian–Valanginian (French Jura)

When quantifying sedimentary processes on shallow carbonate platforms, it is important to know the high-frequency accommodation changes through time. Accommodation changes in cyclic successions are often analysed by simply converting cycle thickness to Fischer plots. This approach is not satisfactory, because it does not account for differential compaction, possible erosion, sea-level fall below the depositional surface, or subtidal cycles. An attempt is made here to reconstruct a realistic, high-frequency accommodation and sea-level curve based on a detailed facies and cyclostratigraphical analysis of Middle Berriasian to Lower Valanginian sections in the French Jura Mountains. The general depositional environment was a shallow-marine carbonate platform on a passive margin. Our approach includes the following steps: (1) facies interpretation; (2) cyclostratigraphical analysis and identification of Milankovitch parameters in a well-constrained chronostratigraphic framework; (3) differential decompaction according to facies; (4) estimation of depth ranges of erosion and vadose zone; (5) estimation of water-depth ranges at sequence boundaries and maximum flooding intervals; (6) estimation of mean subsidence rate; (7) classification of depositional sequences according to types of facies evolution: ‘catch-up’, ‘catch-down’, ‘give-up’, or ‘keep-up’; (8) classification of depositional sequences according to long-term sea-level evolution: ‘rising’, ‘stable’, ‘falling’; (9) calculation of ‘eustatic’ sea-level change for each depositional sequence using the parameters inferred from these scenarios, assuming that sea-level cycles were essentially symmetrical (which is probable in Early Cretaceous greenhouse conditions); (10) calculation of a sea-level curve for each studied section; (11) comparison of these curves among each other to filter out differential subsidence; (12) construction of a ‘composite eustatic’ sea-level curve for the entire studied platform; (13) spectral analysis of the calculated sea-level curves. Limitations of the method are those common to every stratigraphic analysis. However, the method has the potential to improve the original cyclostratigraphical interpretations and to better constrain the high-frequency sea-level changes that control carbonate production and sediment fluxes.     

Intracellular signalling proteins as ‘smart’ agents in parallel distributed processes

In eucaryotic organisms, responses to external signals are mediated by a repertoire of intracellular signalling pathways that ultimately bring about the activation/inactivation of protein kinases and/or protein phosphatases. Until relatively recently, little thought had been given to the intracellular distribution of the components of these signalling pathways. However, experimental evidence from a diverse range of organisms indicates that rather than being freely distributed, many of the protein components of signalling cascades show a significant degree of spatial organisation. Here, we briefly review the roles of ‘anchor’, ‘scaffold’ and ‘adaptor’ proteins in the organisation and functioning of intracellular signalling pathways. We then consider some of the parallel distributed processing capacities of these adaptive systems. We focus on signalling proteins-both as individual ‘devices’ (agents) and as ‘networks’ (ecologies) of parallel processes. Signalling proteins are described as ‘smart thermodynamic machines’ which satisfy ‘gluing’ (functorial) roles in the information economy of the cell. This combines two information-processing views of signalling proteins. Individually, they show ‘cognitive’ capacities and collectively they integrate (cohere) cellular processes. We exploit these views by drawing comparisons between signalling proteins and verbs. This text/dialogical metaphor also helps refine our view of signalling proteins as context-sensitive information processing agents.     

Transitions between cooperative and non-cooperative responding in the 'Pigeon's Dilemma'

Two pigeons played Iterated Prisoner's Dilemma (IPD) against a simulated opponent pre-programmed to play ‘Tit-For-Tat’ (TFT) and ‘Random’ (RND) strategies. Each pigeon received differential amounts of access to food following choices of either ‘cooperate’ or ‘defect’ on a trial. After 1000 trials against TFT and 500 trials against RND, results indicated that choice allocation was optimal when the birds played against RND but was sub-optimal when the birds played against TFT. In order to determine why the pigeons responded suboptimally against TFT, a trial-by-trial analysis of the data was conducted. The analysis revealed that once a pigeon had received the ‘Sucker's’ payoff (S), it was more likely to defect and receive the ‘Temptation’ payoff (T) than to cooperate and receive the ‘Reward’ (R) payoff. Local reinforcement contingencies appear to determine suboptimal responding against TFT in the iterated Pigeon's Dilemma.     

Formation of triton WR 1339-filled rat liver lysosomes : II. Involvement of autophagy and of pre-existing lysosomes

The participation of endocytosis in the formation of Triton-filled lysosomes was followed after injecting Triton WR 1339 simultaneously with colloidal gold or horseradish peroxidase. According to cytomorphometric measurements Triton WR 1339 also significantly enhances autophagy. The analysis of the influence of Triton WR 1339 subfractions shows that autophagy is only augmented by the polymer component (‘macrotriton’) but not by the low molecular component (‘microtriton’) alone. When the latter was injected combined with either macrotriton or colloidal gold particles, autophagy increased to a level observed with Triton WR 1339 and beyond the levels determined for either component alone. Thus, autophagy appears to be stimulated by endocytosis. Autolysosomes are transformed within a few hours to peribiliary ‘dense bodies’. These do not display any significant turnover rate within a period of several days; therefore, dense bodies could be prelabelled with colloidal gold in order to show that they are the target organelles ingesting (macro-)Triton. According to difference spectra autophagy leads to a considerable concentration of microsomal and mitochondria! cytochromes in (macro-)Triton-filled lysosomes far beyond the level detected in ‘normal’ lysosomes. Because of the participation of both hetero- and autophagy in the formation of Triton WR 1339-filled lysosomes they have to be classified as telolysosomes.     

Human time in tree rings

‘Human time’ means time in the context of human culture and activities. It is shown how ‘human time’ is biologically archived in and dendrochronologically extracted from tree rings. For illustration, examples in the late medieval Hanseatic city of Lübeck are selected.     

Some Aspects of Spermiogenesis and Spermatozoan Ultrastructure in Echiniscoides sigismundi (Heterotardigrada: Echiniscoididae)

Some stages of spermiogenesis of the marine heterotardigrade Echiniscoides sigismundi were investigated employing conventional electron microscopy. Spermatids are connected to each other by cytoplasmic bridges. A large vesicle originating from dictyosomes is formed in early spermatids; it becomes condensed in later stages (‘dense body’). Early spermatids contain two mitochondria closely attached and largely unmodified. In an advanced stage of development a (pseudo?) acrosome is formed close to the nucleus. Formation takes place at the face of the nucleus opposite the dictyosomes that had contributed to the dense body. Numerous microtubules lie near the centriole and throughout the cytoplasm. In late spermatids mitochondria located in a membrane-bounded sac lying more or less parallel to the flagellum. These ‘free mitochondria’ as well as the elongated nucleus with the (pseudo?) acrosome give the spermatozoon two additional ‘tails’. Data on spermiogenesis and spermatozoon ultrastructure mainly in marine Heterotardigrada are still very limited and often too anecdotal to allow reasonable conclusions to be drawn. However, structural features shared by Eu- and Heterotardigrada are emphasised.     

Fatty acid composition in microspore-derived secondary embryos of Brassica napus L.

Fatty acid (FA) composition was determined in secondary embryos (SeEs) of Brassica napus L. of the cv. ‘Topas’ and ‘Janetzki’, and compared with the FA composition in microspore-derived embryos (MDEs) and seeds. SeEs of ‘Topas’, a rapessed cultivar with low erucic acid, revealed the same FA composition as observed in the MDEs. The FA pattern was, in most of the cases, independent of the procedures used for induction of SeEs e.g. low density cultures, transversal wounding, auxin treatment, and light conditions. However, non-embryogenic calli, as well as leaves from greenhouse- and in vitro-grown material had a FA composition distinctly different from the MDEs or SeEs. SeEs with an abnormal phenotype revealed differences in FA composition compared to MDEs or SeEs, but was distinct from the composition of non-embryogenic tissues. Virtually no erucic acid (22:1) or eicosaenoic acid (20:1) could be detected in SeEs of ‘Topas’. However, its presence in SeEs of ‘Janetzki’, a high erucic acid rapeseed cultivar, demonstrates that SeEs contain embryo-specific FAs. Under standard culture conditions, the levels of 22:1 and 20:1 were the same as observed in MDEs, which was approximately half the content observed in the seeds. The similarity in FA composition between SeEs and MDEs, of both low and high erucic acid rapeseed cultivars, is a unique characteristic which differs from most other somatic embryogenic systems.