Proposal to reclassify Paenibacillus larvae subsp. pulvifaciens DSM 3615 (ATCC 49843) as Paenibacillus larvae subsp. larvae. Results of a comparative biochemical and genetic study

The bacterial pathogen Paenibacillus larvae subsp. larvae (P. l. larvae), is the etiological agent of American foulbrood, an extremely contagious and disastrous disease of honeybee brood. In case of American foulbrood the destruction of infected colonies is often considered the only workable control measure. Therefore, the ability to diagnose this disease properly is important to prevent unnecessary economic loss to beekeepers. The development of suitable methods for the early and reliable detection of P. l. larvae is hampered by the fact that the two subspecies of Paenibacillus larvae, P. l. larvae and Paenibacillus larvae subsp. pulvifaciens (P. l. pulvifaciens), seem to be indistinguishable by cultural characteristics as well as by PCR protocols. Here we present an extensive analysis of several P. larvae reference strains. We employed conventional culture techniques, morphological and biochemical identification, PCR-based methods and sequencing of the 16S rDNA. We found indeed that P. l. pulvifaciens strain DSM 3615 is indistinguishable from P. l. larvae (DSM 7030). We did not face any problems to discriminate between P. l. larvae and P. l. pulvifaciens strains DSM 8442 and DSM 8443. Therefore, classification of DSM 3615 as type strain of P. l. pulvifaciens seems not to be justified. We propose to reclassify this strain as P. l. larvae. Former problems in differentiating the two subspecies might have arisen from this misclassification. PCR-based methods as well as appropriate biochemical identification systems provide a reliable means for the discrimination between the two subspecies P. l. larvae and P. l. pulvifaciens.     

Influence of lipid physical state on the in vitro digestibility of emulsified lipids

The objective of this study was to investigate the influence of the physical state of emulsified lipids on their in vitro digestibility by pancreatic lipase. A 10 wt % tripalmitin oil-in-water emulsion stabilized by sodium dodecyl sulfate (0.9 wt % SDS) was prepared at a temperature (>70 degrees C) above the melting point of the lipid phase (T(m) approximately 60 degrees C). A portion of this emulsion was cooled to a temperature (0 degrees C for 15 min) well below the crystallization temperature of the emulsified lipid (T(c) approximately 22 degrees C) and then warmed to 37 degrees C so as to have completely solid lipid particles. Another portion of the emulsion was directly cooled from 70 to 37 degrees C (which is above the T(c)) to have completely liquid (supercooled) lipid particles. Pancreatic lipase (8 mg/mL) and bile extract (5.0 mg/mL) were then added to each emulsion at 37 degrees C, and the evolution of the particle charge, particle size, appearance, and free fatty acid release were measured over a period of 2 h. It was found that the rate and extent of lipid digestion were higher in the emulsion containing liquid particles but that appreciable lipid digestion still occurred in the emulsion containing solid particles (i.e., >35% lipid digestion after 2 h). These results may have important consequences for controlling the digestion rate of lipids or for developing solid lipid particle delivery systems for lipophilic functional components.     

The fog problem in Central Asia – Deficiencies in international community research to support water and food security

Central Asian water planning following international policy recommendations and ‘blue prints’ has caused more harm rather than benefiting local communities. International research has not been sufficient to contribute in practical terms to water and food security. This paper reflects potential factors that limit understanding the complexity of water management in Central Asia. Five factors are identified which prevent cross linking of research across international boundaries and within countries. These are: (1) language, (2) access, (3) wikipediarism, (4) smattering and (5) outdating. To change the situation two factors are still missing – a lost generation of local experts and an internal critical review.     

Genomic prediction of sunflower hybrid performance

Predicting single‐cross performance is of high importance to improve the efficiency of sunflower (Helianthus annuus L.) hybrid breeding programmes. We used experimental data from inter‐ and intragroup sunflower hybrids and their parental lines adapted to Central Europe to (i) study the genetic diversity and combining ability and (ii) examine the accuracy to predict hybrid performance based on phenotypic and genomic data. We evaluated 133 intragroup and 104 intergroup hybrids with their parental lines in replicated trials at four environments for grain yield, oil yield and oil content. Furthermore, the parental lines were fingerprinted with 572 AFLP markers. Variance due to specific combining ability was comparable for intergroup and intragroup crosses. This suggested a lack of clearly defined heterotic groups for the sample of studied sunflower lines. Prediction accuracy of hybrid performance based on general combining ability effects was high and could not be increased using genomic selection approaches. For situations where no information on GCA effects of parental lines was available, hybrid prediction based on genomic selection methods was accurate for groups of related lines. For groups of unrelated lines, however, we observed a strong decrease in the prediction accuracy. This suggests that prediction of hybrid performance for crosses based on genetically distant parents remains challenging.     

Combining frost tolerance,high grain yield and good pasta quality in durum wheat

Growing in Central Europe winter instead of spring durum wheat would substantially increase yield potential but is currently hampered by the lack of knowledge of frost tolerance present in elite material. The objectives of our survey were to (i) study the genetic variability and heritability of frost tolerance and its association with other important agronomic and quality traits in durum wheat, (ii) examine the potential to combine frost tolerance with high quality and high grain yield and (iii) investigate the consequences of the heritabilities and associations among traits on the optimum design of a multistage selection programme for winter durum wheat. We investigated 101 elite winter durum wheat lines and four commercial checks in field trials at four locations. Four agronomic as well as nine quality traits were recorded. In addition, frost tolerance was evaluated using a semi‐controlled test resulting in high‐quality phenotypic data. Genotypic variances (σ²_G) were significantly larger than zero for all traits, and heritabilities were moderate to high. Several elite durum wheat lines exhibited a frost tolerance comparable to that of two frost‐tolerant Triticum aestivum varieties. Frost tolerance was not negatively associated with other important agronomic and quality traits. The high quality of the phenotypic data for frost tolerance evaluated in a semi‐controlled test suggests that this is a cost‐efficient approach to consider frost tolerance at early stages of a multistage durum wheat breeding programme.     

Factors affecting lycopene oxidation in oil-in-water emulsions

Evidence that dietary lycopene decreases the risk for a number of health conditions has generated new opportunities for the addition of lycopene to functional foods. This work examined the potential of oil-in-water emulsions as a lycopene delivery system for foods. Oil-in-water emulsions containing lycopene were prepared using different kinds of surfactant (cationic, anionic, and nonionic) and oil types (corn oil, stripped corn oil, and hexadecane). The formation of fatty acid oxidation products and the degradation of lycopene and tocopherol were then monitored. Fatty acids and lycopene had greater stability in oil-in-water emulsions stabilized by cationic dodecyltrimethylammonium bromide (DTAB) or nonionic polyoxyethylene (23) lauryl ether than by anionic sodium dodecyl sulfate (SDS). Oxidative stability in the corn oil-in-water emulsions stabilized by SDS was in the following order: tocopherolhexadecane>tocopherol-stripped corn oil. Lycopene degradation rates were similar in emulsions with and without fatty acids, suggesting that lycopene loss was independent of the presence of fatty acids. These results suggest that the stability of lycopene in oil-in-water emulsions could be inhibited by altering the emulsion droplet interface and by the presence of tocopherols.