A mutation of the cellulose-synthase-like (CslF6) gene in barley (Hordeum vulgare L.) partially affects the β-glucan content in grains

The chemical induced barley mutant m351 was first selected for its low level of mixed-linkage (1–3,1–4) beta-D-glucan (MLG) in an experimental effort to search for barley lines with varied grain MLG contents. The MLG decrease in m351 was associated with increased levels of fructans and crude fiber, but maintained the same plant characteristics under field conditions. The mutation was mapped to a genetic locus flanked by two SSR markers, Bmag369 and Bmag564, on chromosome 7H. Molecular cloning of the CslF6 gene from the m351 line revealed the presence of a point mutation, causing a substitution of an alanine for threonine at position 849 in the amino acid sequence of the corresponding protein. The resultant protein retains some functionality and affects other components in the m351 grain. Those metabolic changes associated with MLG reduction in m351 is the first case reported of a partially functional CslF6 gene in cereal grains. The results contribute to better understanding of the functional effects of the CslF6 gene and the mutant has potential implications in grain end-use quality improvement.     

Coccolithophores: functional biodiversity, enzymes and bioprospecting

Emiliania huxleyi is a single celled, marine phytoplankton with global distribution. As a key species for global biogeochemical cycling, a variety of strains have been amassed in various culture collections. Using a library consisting of 52 strains of E. huxleyi and an 'in house' enzyme screening program, we have assessed the functional biodiversity within this species of fundamental importance to global biogeochemical cycling, whilst at the same time determining their potential for exploitation in biocatalytic applications. Here, we describe the screening of E. huxleyi strains, as well as a coccolithovirus infected strain, for commercially relevant biocatalytic enzymes such as acid/alkali phosphodiesterase, acid/alkali phosphomonoesterase, EC1.1.1-type dehydrogenase, EC1.3.1-type dehydrogenase and carboxylesterase.     

Overweight in urban, low-income, African American and Hispanic children attending Los Angeles elementary schools: research stimulating action

OBJECTIVE: This study was undertaken to establish the prevalence and severity of nutritional problems among low-income children of elementary school age in the Los Angeles Unified School District (LAUSD) in order to collect baseline data to inform policy-makers. DESIGN AND METHODS: A cross-sectional survey of children in 14 elementary schools was conducted from January to June, 1998. Nine hundred and nineteen children were measured and interviewed. The planning, design and data analysis were carried out in collaboration with key LAUSD policy-makers. RESULTS: More than 35% of the sample was classified as being at risk for overweight or overweight according to body mass index. CONCLUSION: There is a high prevalence of children who are at risk for overweight or who are overweight in Los Angeles. This finding has triggered the development of multiple school-based intervention programmes.     

Prolonged transit time through the stomach and small intestine improves iron dialyzability and uptake in vitro

The iron dialyzability and uptake in relation to transit time through the stomach and small intestine was investigated using a dynamic in vitro gastrointestinal model in combination with Caco-2 cells. Three test meals were evaluated, consisting of lactic fermented vegetables with white (I) or whole meal bread (II) and of sourdough-fermented rye bread (III). Three transit times were tested (fast, medium, and slow transport). Iron dialyzability and absorption differed significantly between medium and slow transit time for meal I and between fast and medium transit time for meal III. For meal II, high in phytate, the iron dialyzability and absorption were low irrespective of transit time. The meals could be ranked with respect to iron dialyzability and uptake in the order I > III > II. Although the in vitro models used have limitations compared to in vivo experiments, the results suggest that an increased transit time may improve iron availability.     

Zinc hyperaccumulation in Thlaspi caerulescens. II. Influence on organic acids

The influence of different zinc (Zn) concentrations (1.5 to 1500 μM) on organic acid levels in roots and shoots of the Zn‐hyperaccumulator plant Thlaspi caerulescens was investigated. In shoots, malate was the most abundant organic acid (164 to 248 μmol/g f.w.), followed by citrate, succinate, and oxalate. A significant correlation between soluble Zn and both malate and oxalate was observed in shoots, but not in roots. In shoots, a significant correlation between inorganic cation equivalents and organic acid anion equivalents was found. These observations and the finding, that organic acid concentrations were high even under suboptimal Zn supply (1.5 μM) suggest that in T. caerulescens the high organic acid concentration in shoots is a constitutive property. The variation of the organic acid concentrations seem to be a consequence of the cation‐anion balance rather than a specific Zn tolerance mechanism. The constitutively high organic acid concentration may be responsible for the high Zn and iron (Fe) tissue concentrations required for optimum growth in T. caerulescens.     

Effects of maternal nutrition and porcine growth hormone (pGH) treatment during gestation on endocrine and metabolic factors in sows, fetuses and pigs, skeletal muscle development, and postnatal growth

Prenatal growth is very complex and a highly integrated process. Both maternal nutrition and the maternal somatotropic axis play a significant role in coordinating nutrient partitioning and utilization between maternal, placental and fetal tissues. Maternal nutrition may alter the nutrient concentrations and in turn the expression of growth regulating factors such as IGFs and IGFBPs in the blood and tissues, while GH acts in parallel via changing IGFs/IGFBPs and nutrient availability. The similarity in the target components implies that maternal nutrition and the somatotropic axis are closely related to each other and may induce similar effects on placental and fetal growth. Severe restriction of nutrients throughout gestation has a permanent negative effect on fetal and postnatal growth, whereas the effects of both temporary restriction and feeding above requirements during gestation seem to be of transitional character. Advantages in fetal growth gained by maternal growth hormone treatment during early to mid-gestation are not maintained to term, whereas treatment during late or greatest part of gestation increases progeny size at birth, which could be of advantage for postnatal growth. This review summarizes the available knowledge on the effects of different maternal feeding strategies and maternal GH administration during pregnancy and their interactions on metabolic and hormonal (especially IGFs/IGFBPs) status in the feto-maternal unit, skeletal muscle development and growth of the offspring in pigs.     

Relationship Between Echocardiographic Measurements and Body Size in Horses

The objectives of this study were to evaluate the optimal body size variable, and to determine mathematical model that best fits echocardiographic measurements to body size in the equine species. One hundred fifty horses of various breeds, aged 1 week to 17 years, body weight (BW) 38-890 kg, and free from cardiac disease were used in this study. Based on their age (ie, younger or older than 2 years), animals were separated into two groups. In each horse, the BW, height at withers (HT), thoracic circumference (TC), and the body length were measured; the body surface area was calculated; and a standard two-dimensional and M-mode echocardiography was performed allowing classic cardiac measurements to be taken. Correlations between each echocardiographic measurement and each of the anthropometric variables were assessed via a Pearson's product-moment analysis and using linear, logarithmic, and power regression analysis in all animals and within the two groups. The dimensional, but not functional, echocardiographic measurements showed a close correlation with all body size variables, especially during growth. The relationship between cardiac measurements and body size was best described using power regression models with TC as the anthropometric variable, but the relationship was also very accurately described using BW, body surface area, or body length. In the equine species, dimensional echocardiographic reference values should be established using power regression equations on TC. Such a correction for body size could increase the diagnostic value of echocardiography in equine cardiology.     

Effect of infectious dose and season on development of hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

Hemorrhagic pneumonia is an acute and fatal disease of farmed mink caused by Pseudomonas aeruginosa. The pathogenesis of this disease has not yet been resolved. Mink are the only animals known to be susceptible to acute, contagious, and fatal lung infections caused by P. aeruginosa. The purpose of this study was to investigate the correlation between dose-response and season of infection and to clarify whether Danish mink are carriers of P. aeruginosa on their nasal mucosa during the season for hemorrhagic pneumonia. To elucidate the pathogenesis of the disease, an infectious dose-response trial was carried out on adult mink and mink kits, both in the season for hemorrhagic pneumonia (November) as well as out of season (July). It proved difficult to infect mink via the intra-nasal route. Only 4 out of 60 infected mink developed clinical disease and were euthanized, all of them in November, illustrating that predisposing factors in the mink itself and not infectious dose might be crucial for disease development. We were able to culture P. aeruginosa from the nasal cavity of the clinically healthy experimental mink 8 d after inoculation. This indicated that the mink can carry P. aeruginosa on their nasal mucosa without developing the disease. It was not possible, however, to culture P. aeruginosa from the nasal cavity of clinically healthy mink obtained from farms in November, which indicates that the organism is not a normal part of the nasal mucosal flora of mink.