Malacosporean-like spores in urine of rainbow trout react with antibody and DNA probes to Tetracapsuloides bryosalmonae

Tetracapsuloides bryosalmonae is the myxozoan parasite causing proliferative kidney disease (PKD) of salmonid fishes in Europe and North America. The complete life cycle of the parasite remains unknown despite recent discoveries that the stages infectious for fish develop in freshwater bryozoans. During the course of examinations of the urine of rainbow trout (Oncorhynchus mykiss) with or recovering from PKD we identified spores with features similar to those of T. bryosalmonae found in the bryozoan host. Spores found in the urine were subspherical, with a width of 16 mum and height of 14 mum, and possessed two soft valves surrounding two spherical polar capsules (2 mum in diameter) and a single sporoplasm. The absence of hardened valves is a distinguishing characteristic of the newly established class Malacosporea that includes T. bryosalmonae as found in the bryozoan host. The parasite in the urine of rainbow trout possessed only two polar capsules and two valve cells compared to the four polar capsules and four valves observed in the spherical spores of 19 mum in diameter from T. bryosalmonae from the bryozoan host. Despite morphological differences, a relationship between the spores in the urine of rainbow trout and T. bryosalmonae was demonstrated by binding of monoclonal and polyclonal antibodies and DNA probes specific to T. bryosalmonae.

Seasonal 'fall out' of sessile macro-fauna from submarine cliffs: quantification, causes and implications

Submarine cliffs are typically crowded with sessile organisms, most of which are ultimately exported downwards. Here we report a 24 month study of benthic fauna dropping from such cliffs at sites of differing cliff angle and flow rates at Lough Hyne Marine Nature Reserve, Co. Cork, Ireland. The magnitude of 'fall out' material collected in capture nets was highly seasonal and composed of sessile and mobile elements. Sponges, ascidians, cnidarians, polychaetes, bryozoans and barnacles dominated the sessile forms. The remainder (mobile fauna) were scavengers and predators such as asteroid echinoderms, gastropod molluscs and malacostracan crustaceans. These were probably migrants targeting fallen sessile organisms. 'Fall out' material (including mobile forms) increased between May and August in both years. This increase in 'fall out' material was correlated with wrasse abundance at the cliffs (with a one month lag period). The activities of the wrasse on the cliffs (feeding, nest building and territory defence) were considered responsible for the majority of 'fall out' material, with natural mortality and the activity of other large mobile organisms (e.g. crustaceans) also being triplicated. Current flow rate and cliff profile were important in amount of 'fall out' material collected. In low current situations export of fallen material was vertical, while both horizontal and vertical export was associated with moderate to high current environments. Higher 'fall out' was associated with overhanging than vertical cliff surfaces. The 'fall out' of marine organisms in low current situations is likely to provide ail important source of nutrition in close proximity to the cliff, in an otherwise impoverished soft sediment habitat. However, in high current areas material will be exported some distance from the source, with final settlement again occurring in soft sediment habitats (as current speed decreases).

Analysis of the antigen combining site: Correlations between length and sequence composition of the hypervariable loops and the nature of the antigen

It has long been suggested that the overall shape of the antigen combining site (ACS) of antibodies is correlated with the nature of the antigen. For example, deep pockets are characteristic of antibodies that bind haptens, grooves indicate peptide binders, while antibodies that bind to proteins have relatively flat combining sites. In. 1996, MacCallum, Martin and Thornton used a fractal shape descriptor and showed a strong correlation of the shape of the binding region with the general nature of the antigen. However, the shape of the ACS is determined primarily by the lengths of the six complementarity-determining regions (CDRs). Here, we make a direct correlation between the lengths of the CDRs and the nature of the antigen. In addition, we show significant differences in the residue composition of the CDRs of antibodies that bind to different antigen classes. As well as helping us to understand the process of antigen recognition, autoimmune disease and cross-reactivity these results are of direct application in the design of antibody phage libraries and modification of affinity. (C) 2003 Elsevier Science Ltd. All rights reserved.

X-ray scattering study of the effect of hydration on the cross-beta structure of amyloid fibrils

We have investigated the effect of sample hydration on the wide-angle X-ray scattering patterns of amyloid fibrils from two different sources, hen egg white lysozyme (HEWL) and an 11-residue peptide taken from the sequence of transthyretin (TTR105-115). Both samples show an inter-strand reflection at 4.7 Å and an inter-sheet reflection which occurs at 8.8 and 10 Å for TTR105-115 and HEWL fibrils, respectively. The positions, widths, and relative intensities of these reflections are conserved in patterns obtained from dried stalks and hydrated samples over a range of fibril concentrations. In 2D scattering patterns obtained from flow-aligned hydrated samples, the inter-strand and inter-sheet reflections showed, respectively, axial and equatorial alignment relative to the fibril axis, characteristic of the cross-β structure. Our results show that the cross-β structure of the fibrils is not a product of the dehydrating conditions typically employed to produce aligned samples, but is conserved in individual fibrils in hydrated samples under dilute conditions comparable to those associated with other biophysical and spectroscopic techniques. This suggests a structure consisting of a stack of two or more sheets whose interfaces are inaccessible to bulk water.

Interaction of heat-moisture conditions and physical properties in oat processing: I. Mechanical properties of steamed oat groats

Research interest in oats has focussed on their nutritional value, but there have been few studies of their food processing. Heat treatment is characteristic of oat processing, as it is needed to inactivate lipase and to facilitate flaking. A Texture Analyser was used to characterise the mechanical properties of unkilned and kilned oat groats after steaming and tempering in an oven for 30, 60 and 90 min at 80, 95 and 110 degrees C. Maximum force, number of peaks before maximum and final force after 5s hold were used to characterise the behaviour of the groats during compression. Kilned groats were larger and softer before steaming. After steaming and tempering, the moisture content of the kilned groats was higher than for unkilned groats. Hot, steamed oats were softer than cold, unsteamed groats, indicated by a decrease in maximum force from 59 to 55 N, and there was no significant difference between kilned and unkilned groats. However, higher temperatures during tempering increased maximum force. These results suggest that mild steam treatment yields softer oat groats, whereas cold or over-treated groats tend to be harder. (c) 2007 Elsevier Ltd. All rights reserved.

Induction of aquaporin 1 but not aquaporin 4 messenger RNA in rat primary brain microvessel endothelial cells in culture

Aquaporins (AQPs) are a family of proteins that mediate water transport across cells, but the extent to which they are involved in water transport across endothelial cells of the blood-brain barrier is not clear. Expression of AQP1 and AQP4 in rat brain microvessel endothelial cells was investigated in order to determine whether these isoforms were present and, in particular, to examine the hypothesis that brain endothelial expression of AQPs is dynamic and regulated by astrocytic influences. Reverse-transcriptase-polymerase chain reaction (RT-PCR) and immunocytochemistry showed that AQP1 mRNA and protein are present at very low levels in primary rat brain microvessel endothelial cells, and are up-regulated in passaged cells. Upon passage, endothelial cell expression of mdr1a mRNA is decreased, indicating loss of blood-brain barrier phenotype. In passage 4 endothelial cells, AQP1 mRNA levels are reduced by coculture above rat astrocytes, demonstrating that astrocytic influences are important in maintaining the low levels of AQP1 characteristic of the blood-brain barrier endothelium. Reverse-transcriptase-PCR revealed very low levels of AQP1 mRNA present in the RBE4 rat brain microvessel endothelial cell line, with no expression detected in primary cultures of rat astrocytes or in the C6 rat glioma cell line. In contrast, AQP4 mRNA is strongly expressed in astrocytes, but no expression is found in primary or passaged brain microvessel endothelial cells, or in RBE4 or C6 cells. Our results support the concept that expression of AQP1, which is seen in many non-brain endothelia, is suppressed in the specialized endothelium of the blood-brain barrier.

The role of monounsaturated fatty acids in the mitigation of insulin resistance

With the rising rate of obesity, there is considerable interest in dietary strategies to reduce insulin resistance, a major characteristic of the metabolic syndrome and type 2 diabetes. Diets rich in monounsaturated fatty acids (MUFA) have been suggested as an alternative to low-fat, high-carbohydrate diets to improve glycemic control. However, inconsistent effects have been observed with MUFA-rich diets in both healthy and insulin-resistant individuals. In studies that have reported favorable effects on insulin sensitivity, Mediterranean-style diets have been used that are rich not only in MUFA but also whole-grain foods, fiber, and carbohydrates with a low glycemic index. There is a need for intervention studies to examine the true impact of MUFA-rich oils on glycemic control in both Mediterranean and non-Mediterranean populations. In addition, the metabolic and genotypic status of the participants may also play a role in the inter-individual variability in insulin sensitivity in response to MUFA-rich diets.

Spectral invariant behavior of zenith radiance around cloud edges observed by ARM SWS

The ARM Shortwave Spectrometer (SWS) measures zenith radiance at 418 wavelengths between 350 and 2170 nm. Because of its 1-sec sampling resolution, the SWS provides a unique capability to study the transition zone between cloudy and clear sky areas. A spectral invariant behavior is found between ratios of zenith radiance spectra during the transition from cloudy to cloud-free. This behavior suggests that the spectral signature of the transition zone is a linear mixture between the two extremes (definitely cloudy and definitely clear). The weighting function of the linear mixture is a wavelength-independent characteristic of the transition zone. It is shown that the transition zone spectrum is fully determined by this function and zenith radiance spectra of clear and cloudy regions. An important result of these discoveries is that high temporal resolution radiance measurements in the clear-to-cloud transition zone can be well approximated by lower temporal resolution measurements plus linear interpolation.

Time-resolved gas-phase kinetic, quantum chemical and RRKM studies of reactions of silylene with cyclic ethers

Time-resolved kinetic studies of silylene, SiH2, generated by laser flash photolysis of phenylsilane, have been carried out to obtain rate constants for its bimolecular reactions with oxirane, oxetane, and tetrahydrofuran (THF). The reactions were studied in the gas phase over the pressure range 1-100 Torr in SF6 bath gas, at four or five temperatures in the range 294-605 K. All three reactions showed pressure dependences characteristic of third-body-assisted association reactions with, surprisingly, SiH2 + oxirane showing the least and SiH2 + THF showing the most pressure dependence. The second-order rate constants obtained by extrapolation to the high-pressure limits at each temperature fitted the Arrhenius equations where the error limits are single standard deviations: log(k(oxirane)(infinity)/cm(3) molecule(-1) s(-1)) = (-11.03 +/- 0.07) + (5.70 +/- 0.51) kJ mol(-1)/RT In 10 log(k(oxetane)(infinity)/cm(3) molecule(-1) s(-1)) = (-11.17 +/- 0.11) + (9.04 +/- 0.78) kJ mol(-1)/RT In 10 log(k(THF)(infinity)/cm(3) molecule(-1) s(-1)) = (-10.59 +/- 0.10) + (5.76 +/- 0.65) kJ mol(-1)/RT In 10 Binding-energy values of 77, 97, and 92 kJ mol(-1) have been obtained for the donor-acceptor complexes of SiH2 with oxirane, oxetane, and THF, respectively, by means of quantum chemical (ab initio) calculations carried Out at the G3 level. The use of these values to model the pressure dependences of these reactions, via RRKM theory, provided a good fit only in the case of SiH2 + THF. The lack of fit in the other two cases is attributed to further reaction pathways for the association complexes of SiH2 with oxirane and oxetane. The finding of ethene as a product of the SiH2 + oxirane reaction supports a pathway leading to H2Si=O + C2H4 predicted by the theoretical calculations of Apeloig and Sklenak.

Floral ontogeny in Polygalaceae and its bearing on the homologies of keeled flowers in Fabales

Keeled flowers are characteristic of many species of Polygalaceae (tribe Polygaleae), in which there is often a distinctive crest located at the abaxial petal. This study of floral ontogeny across the entire family highlights potential suites of characters that relate to the evolution of keeled and crested flowers. One character suite encompasses interconnected transformations of the lateral perianth organs acting as an evolutionary module: bracteoles, lateral sepals (with delayed initiation and petaloid appearance), and lateral petals (suppressed or lost). The plastochron between initiation of the lateral sepals and that of the other sepals is relatively long in the tribe Polygaleae, in which the calyx is usually heteromorphic. By contrast, in the petal whorl, the difference between a zygomorphic and an actinomorphic corolla involves organ suppression rather than heterochrony. Four primary androecial patterns are identified in the family, and the gynoecium ranges between syncarpous‐bicarpellate and multicarpellate. Stigma diversity is based on two primary morphological types: one in which the papillate stigmatic surfaces lie close together, the other in which they are physically separated. The floral ontogeny of Polygalaceae is considered alongside comparative data available for other members of the order Fabales, and hypotheses to account for the similarities and differences between keeled flowers are discussed.

Adaptive divergence and speciation among sexual and pseudoviviparous populations of Festuca

Pseudovivipary is an environmentally induced flowering abnormality in which vegetative shoots replace seminiferous (sexual) inflorescences. Pseudovivipary is usually retained in transplantation experiments, indicating that the trait is not solely induced by the growing environment. Pseudovivipary is the defining characteristic of Festuca vivipara, and arguably the only feature separating this species from its closest seminiferous relative, Festuca ovina. We performed phylogenetic and population genetic analysis on sympatric F. ovina and F. vivipara samples to establish whether pseudovivipary is an adaptive trait that accurately defines the separation of genetically distinct Festuca species. Chloroplast and nuclear marker-based analyses revealed that variation at a geographical level can exceed that between F. vivipara and F. ovina. We deduced that F. vivipara is a recent species that frequently arises independently within F. ovina populations and has not accumulated significant genetic differentiation from its progenitor. We inferred local gene flow between the species. We identified one amplified fragment length polymorphism marker that may be linked to a pseudovivipary-related region of the genome, and several other markers provide evidence of regional local adaptation in Festuca populations. We conclude that F. vivipara can only be appropriately recognized as a morphologically and ecologically distinct species; it lacks genetic differentiation from its relatives. This is the first report of a ‘failure in normal flowering development’ that repeatedly appears to be adaptive, such that the trait responsible for species recognition constantly reappears on a local basis.

Convergence analysis of stochastic diffusion search

In this paper we present a connectionist searching technique - the Stochastic Diffusion Search (SDS), capable of rapidly locating a specified pattern in a noisy search space. In operation SDS finds the position of the pre-specified pattern or if it does not exist - its best instantiation in the search space. This is achieved via parallel exploration of the whole search space by an ensemble of agents searching in a competitive cooperative manner. We prove mathematically the convergence of stochastic diffusion search. SDS converges to a statistical equilibrium when it locates the best instantiation of the object in the search space. Experiments presented in this paper indicate the high robustness of SDS and show good scalability with problem size. The convergence characteristic of SDS makes it a fully adaptive algorithm and suggests applications in dynamically changing environments.

Amyloid-like fibrillogenesis through supramolecular helix-mediated self-assembly of tetrapeptides containing non-coded alpha-aminoisobutyric acid (Aib) and 3-aminobenzoic acid (m-ABA)

Single-crystal X-ray diffraction studies of two terminally protected tetrapeptides Boc-Ile-Aib-Val-m-ABA-OMe (I) and Boc-Ile-Aib-Phe-m-ABA-OMe (II) (Aib = alpha-aminoisobutyric acid; m-ABA = meta-aminobenzoic acid) reveal that they form continuous H-bonded helices through the association of double-bend (type III and I) building blocks. NMR Studies support the existence of the double-bend (type Ill and I) structures of the peptides in solution also. Field emission scanning electron-microscopic (FE-SEM) and high-resolution transmission electron-microscopic (HR-TEM) images of the peptides exhibit amyloid-like fibrils in the solid state. The Congo red-stained fibrils of peptide I and II, observed between crossed polarizers, show green-gold birefringence, a characteristic of amyloid fibrils.

Fatty acid compositions of inositol and choline phospholipids of breast tumours and normal breast tissue

The fatty acid compositions of the -choline and -inositol phospholipids of breast tumours of women undergoing surgery for treatment of breast disease (malignant n = 12; benign n = 10) and normal breast tissue of women undergoing breast reduction surgery (n = 6) were determined. The fatty acid compositions of erythrocyte phospholipids were also determined in the same subjects and in an additional number of normal healthy volunteers (n = 16). Levels of oleic acid were lower in both phospholipid fractions of erythrocytes of women with breast disease and in the phosphatidylcholine fraction of breast tumours compared with normal breast tissue. Significantly higher levels of linoleic acid were found in erythrocytes of tumour-bearing subjects and a similar trend was evident in the phosphatidylcholine fraction of tumour compared with normal breast tissues. Conversely, lower levels of two of the products of linoleic acid chain elongation and desaturation, dihomogamma-linolenic and arachidonic acids, were found in the erythrocyte phospholipids of tumour-bearing subjects and in the choline phospholipids of breast tumour tissues. These data suggest that in women with breast disease, there may be inhibition of 6-desaturase, and enhanced activity of 9-desaturase, enzymes which play an important role in determining membrane phospholipid fatty acid composition. This pattern of altered fatty acid composition characteristic of erythrocyte phospholipids of tumour-bearing subjects and phosphatidylcholine of breast tumour tissue was less evident in the case of the breast tumour phosphatidylinositol in which differences other than those described were seen.

Changes in the intestinal microbiota after a short period of dietary over-indulgence, representative of a holiday or festival season

The effects on the intestinal microbiota of a short period of marginal over-eating, characteristic of holiday or festival periods, were investigated in a pilot study. Fourteen healthy male subjects consumed a diet rich in animal protein and fat for seven days. During this period, the subjects significantly increased their dietary energy, protein, carbohydrate and fat intakes by 56, 59, 53 and 58%, respectively (all P < 0.05). The mean weight gain of 0.27 kg was less than the expected 1 kg, but this was consistent with a degree of under-reporting on the baseline diet. Fluorescence in situ hybridisation analysis confirmed the relative stability of each individual’s faecal microbiota but showed considerable variations between them. The diet was associated with a significant increase in numbers of total faecal bacteria and the bacteroides group, as detected by the universal bacterial probe (DAPI) and Bacteroides probe (Bac 303), respectively. Overall, there was a decrease in numbers of the Lactobacillus/Enterococcus group (Lab 158 probe; 2.8 ± 3.0% to 1.8 ± 1.8%) and the Bifidobacterium group (Bif 164 probe; 3.0 ± 3.7% to 1.7 ± 1.2%), although there was considerable inter-individual variation. Analysis of the relative proportions of each bacterial group as a percentage of the subject’s total bacteria showed a trend for a change in the intestinal microbiota that might be considered potentially unhealthy.