Impact of Endocrine‐Disrupting Chemicals on Reproductive Function in Zebrafish (Danio rerio)

The prevalence of endocrine‐disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex‐steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild‐type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure.     

Wheat Bran AX Properties and Choice of Xylanase Affect Enzymic Production of Wheat Bran‐Derived Arabinoxylan‐Oligosaccharides

Wheat bran‐derived arabinoxylan‐oligosaccharides (AXOS) recently have been shown to potentially exert prebiotic effects. In this study, 15 bran samples obtained by milling different wheat cultivars were treated with xylanases from Hypocrea jecorina (XHJ), Aspergillus aculeatus (XAA), and Pseudoalteromonas haloplanktis (XPH) to assess the effect of bran source and xylanase properties on the AXOS yield and structure. The total arabinoxylan (AX) extraction yield was higher with XHJ (8.2–10.7%) and XAA (8.2–10.8%) than with XPH (6.9–9.5%). Irrespective of the enzyme, a significant negative correlation was observed between extraction yield and arabinose to xylose (A/X) ratio of bran AX (r = –0.7), but not between yield and bran AX level. The A/X ratio of the extracted material was 0.27–0.34 for all bran samples and all enzymes, which combined with yield data and microscopic analysis, indicated primary hydrolysis of aleurone and nucellar epidermis AX. The average degree of polymerization (avDP) of the extracted AX was very low for all enzymes (2–3), owing to the release of high levels of monomeric arabinose and xylose. The release of these monosaccharides could be ascribed to 1) the activity of wheat bran‐associated enzymes (arabinofuranosidases and xylosidases); 2) the hydrolytic properties of the xylanases themselves; and 3) the presence of xylosidases as contaminations in enzyme preparation, in that order of importance. Heat treatment of bran before xylanase treatment significantly decreased the levels of monomeric arabinose and xylose in the extract, without affecting the extraction yield, resulting in a higher avDP of 3–7, thus yielding true AXOS. Overall, for AXOS production, wheat cultivars with a low bran A/X ratio of the AX are preferable as starting materials, and inactivation of bran‐associated enzymes before incubation is desirable. The XHJ xylanase was the best enzyme for wheat bran‐derived AXOS production.     

Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.     

Measurements of the equation of state of deuterium at the fluid insulator-metal transition

A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography.     

Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.     

Enzymatic Hydrolysis of Barley Starch Lipids

The efficiency of phospholipase and lipase preparations in the hydrolysis of lysophospholipids of native and gelatinized barley starch was examined. The degree of hydrolysis was analyzed by determination of the amount of released fatty acids by an enzymatic method. Thermal and structural properties of the enzyme-treated starch were studied by differential scanning calorimetry and light microscopy. Lysophospholipids of the gelatinized barley starch were easily hydrolyzed, in contrast to the lipids of the granular starch. The maximum degree of hydrolysis achieved for the gelatinized starch was 80% and for the native starch ≈20%. Gelatinization enthalpies and micrographs indicated that even though the amount of the released fatty acids from the native starch was small, formation of free fatty acids inhibited swelling and gelatinization of starch granules.     

Impact of water content on the solubilisation of arabinoxylan during xylanase treatment of wheat bran

Arabinoxylan (AX) has a major impact on the functional properties of wheat bran, and it has been shown that technological properties of bran can be improved by using endoxylanases. Enzymatic treatments are typically conducted at high water content. However, in industrial applications, low water content may be advantageous, especially when targeting dry end products. The aim of the study was to examine the impact of water content, ranging from 20 to 90%, on the efficiency of endoxylanase treatment of wheat bran. Interestingly, AX solubilisation was highest at the water contents of 40 and 90%. At water contents 50–80%, AX solubilisation was lower than at 40 and 90%. Furthermore, at low water content, less depolymerisation was detected. At water content of 40%, the bran-water mixture was transformed from powder-like into compact mass. Probably the compact consistency of the material enhanced AX solubilisation by increased breakdown of bran cell walls due to shear forces or via enhanced enzyme binding to the substrate. The results show that solubilisation of bran AX can also be efficiently performed at low water content.     

Fundamental evaluation of the impact of high Hydrostatic Pressure on oat batters

The use of grains alternative to wheat or rye is a challenging task for cereal technologists, and currently new technologies are under investigation as tools to improve the performances of these alternative grains. In this work the effects of high Hydrostatic Pressure (HP) on oat batters were investigated. Oat batters were treated for 10 min at 200, 300, 350, 400 or 500 MPa. Scanning electron microscopy and bright field microscopy showed that high HP significantly affected oat batter microstructure, and both starch and proteins were affected. Treatment at high HP significantly improved batter viscosity and elasticity. At pressures ≤300 MPa the increase in the viscous component was higher than the increase in the elastic component. On the contrary, at pressures ≥350 MPa the elastic component was predominant. Differential scanning calorimetry revealed that high HP induced starch gelatinisation, which started at 300 MPa and was almost complete after treatment at 500 MPa. High HP also affected water- and salt-soluble as well as urea-soluble oat proteins. Analysis of proteins soluble in different buffers revealed that pressures ≥300 MPa induced the formation of urea-insoluble complexes and/or disulfide bonds. Overall, the extent of starch gelatinisation and protein modification was dependent on the applied pressure, but the results collected so far clearly show that high HP can be used to improve the functionality of oat batters.     

Rye phenolics in nutrition and health

Dietary intake of whole-grain foods is associated with a decreased risk of chronic diseases such as diabetes, obesity and heart disease. In addition to dietary fibre, various phytochemicals have been suggested to contribute to the health effects of whole grain products. This review focuses on phenolic compounds in rye (Secale cereale L.), which is one of the major bread grains in Europe. Data on phenolic concentrations in rye grain and foods, their bioavailability to tissues and effects in vivo, and their potential contributions to health are presented. Phenolic compounds in rye, such as phenolic acids, alkylresorcinols and lignans, are concentrated in the outer layers of the grain. Phenolic acids are the major phenolic compounds in whole grain rye (103–300 mg/100 g grain), ferulic acid being the most abundant. Rye lignans are present at concentrations of 2 mg/100 g grain and had been shown to be converted by the intestinal microflora to the mammalian lignans enterodiol and enterolactone in human intervention studies. Alkylresorcinols (36–320 mg/100 g grain), which have been found to be incorporated into human erythrocyte membranes, are of particular interest due to their potential use as biomarkers of the intake of rye and wheat.     

Fermentation-induced changes in the nutritional value of native or germinated rye

Processing is important both for the sensory and nutritional quality of grains. In the case of whole grains, it especially may influence the levels and bioavailability of the bioactive compounds. Yeast, lactic acid and mixed fermentation were shown to vary in their effects on native and germinated wholemeal rye flour. The presence of Saccharomyces cerevisiae was important for enhanced levels of the analysed compounds. The levels of folates, free phenolic acids, total phenolic compounds, lignans and alkylresorcinols were increased especially by fermentation of germinated rye, which also resulted in lower pH when compared with native rye flour, the level of folate was increased up to seven-fold and that of free phenolic acids by up to ten-fold after germination and fermentation. Tailored fermentation thus offers a tool to further increase the bioactive potential of wholemeal rye.