Variation of DNA fingerprints among accessions within maize inbred lines and implications for identification of essentially derived varieties.

Genetic distances (GDs) based on molecular markers are important parameters for identifying essentially derived varieties (EDVs). In this context information about the variability of molecular markers within maize inbred lines is essential. Our objectives were to (1) determine the variation in the size of simple sequence repeat (SSR) fragments among different accessions of maize inbreds and doubled haploid (DH) lines, (2) attribute the observed variation to genetic and marker system-specific sources, and (3) investigate the effect of SSR fragment size differences within maize lines on the GD between maize lines and their consequences for the identification of essentially derived varieties. Two to five accessions from nine inbred lines and five DH lines were taken from different sources or drawn as independent samples from the same seed lot. Each accession was genotyped with 100 SSR markers that evenly covered the whole maize genome. In total, 437 SSR fragments were identified, with a mean of 4.4 alleles per locus. The average polymorphic information content (PIC) was 0.58. GD estimates between two accessions of the same genotype ranged from 0.00 to 0.12 with an average of 0.029 for inbred lines and 0.001 for DH lines. An average of 11.1 SSRs was polymorphic between accessions of the same inbred line due to non-amplification (8.1 SSRs), heterogeneity (4.0 SSRs) or unknown alleles (2.6 SSRs). In contrast to lab errors, heterogeneity contributed considerably to the observed variation for GD. In order to decrease the probability to be suited for infringing an EDV threshold by chance, we recommend to increase the level of homogeneity of inbred lines before applying for plant variety protection.     

Lack of interaction between the milky disease bacterium Paenibacillus popilliae and stilbene-derived optical brighteners in Japanese beetle larvae

Optical brighteners cansynergistically enhance nucleopolyhedrovirusinfectivity to lepidopteran larvae by blockingthe sloughing of infected primary midgut cellsand inhibiting the formation of the peritrophicmembrane in the hosts. Because of similaritiesin the route of infection, we investigatedwhether optical brighteners would also enhanceinfection with the milky disease bacterium,Paenibacillus popilliae, of Japanesebeetle, Popillia japonica, larvae. Thelarvae were kept in soil mixed with P.popilliae spore preparations and the opticalbrighteners Blankophor BBH, P167, or RKH withperennial ryegrass provided as food. Noenhancing effect of any of the opticalbrighteners on P. popilliae infection wasobserved at a concentration of 0.1% (w/w). Rather, when mixed into the soil at 0.02, 0.1,or 0.5% (w/w) BBH reduced P. popilliaeinfection at the highest rate.     

Incidence of Virulence Factors and Antibiotic Resistance among Enterococci Isolated from Food

The incidence of virulence factors among 48 Enterococcus faecium and 47 Enterococcus faecalis strains from foods and their antibiotic susceptibility were investigated. No strain was resistant to all antibiotics, and for some strains, multiple resistances were observed. Of E. faecium strains, 10.4% were positive for one or more virulence determinants, compared to 78.7% of E. faecalis strains. Strains exhibiting virulence traits were not necessarily positive for all traits; thus, the incidence of virulence factors may be considered to be strain specific.     

Evidence that Sry is expressed in pre-Sertoli cells and Sertoli and granulosa cells have a common precursor.

The expression of Sry in the undifferentiated, bipotential genital ridges of mammalian XY fetuses initiates testis development and is hypothesized to do so by directing supporting cell precursors to develop as Sertoli cells and not as granulosa cells. To directly test this hypothesis, transgenic mice expressing EGFP under the control of the Sry promoter were produced. After establishing that the transgene was expressed in fetal gonads similarly to endogenous Sry, the spatial and temporal expression of the Sry-EGFP transgene was investigated in developing gonads by using confocal microscopy and immunofluorescent histochemistry. This analysis indicated: (1) Sry is first expressed in cells located centrally in the genital ridge and then later in cells located at the cranial and caudal poles, (2) Sry is expressed exclusively in pre-Sertoli cells in the urogenital ridge, and (3) Sertoli and granulosa cells develop from a common precursor. These results support the hypothesis that Sry initiates testis differentiation by directing the development of supporting cell precursors as Sertoli rather than granulosa cells. Furthermore, the Sry expression pattern explains the nonrandom distribution of testicular and ovarian tissue in mammalian ovotestes.     

Anatomical features and histology of the digestive tract of two related neotropical omnivorous fishes (Characiformes; Anostomidae)

The estimated mean intestinal coefficients of Leporinus friderici Bloch, 1794 and L. taeniofasciatus Britski, 1997, from the Upper Tocantins River, central-western Brazil, were 1·25±0·15 and 1·14±0·07, respectively. The external surfaces of the lips have taste buds. The histological structure is composed of four layers: mucosa, submucosa, muscular, and serosa. No muscularis mucosa is detected. The oesophageal epithelium is stratified in L. friderici and pseudostratified in L. taeniofasciatus , the latter with PAS+ basal cells and eosinophilic apical cells. A thick layer of adipose tissue was found within the submucosa. Leporinus taeniofasciatus has a sphincter separating the cardiac and fundic portions of the stomach. In both species, gastric glands are present in the stomach, except in its pyloric portion. The pyloric caeca possess a simple columnar epithelium with brush border and three types of goblet cells. Rodlet cells were found in L. friderici . The three portions of the intestine showed no histological differences. Anatomical and histological features of the digestive tract are consistent with the omnivorous habit of both these species.     

The effectiveness of flower strips and hedgerows on pest control,pollination services and crop yield: a quantitative synthesis

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.     

Perovskite Solar Cells go Outdoors: Field Testing and Temperature Effects on Energy Yield

Perovskite solar cells (PSC) have shown that under laboratory conditions they can compete with established photovoltaic technologies. However, controlled laboratory measurements usually performed do not fully resemble operational conditions and field testing outdoors, with day‐night cycles, changing irradiance and temperature. In this contribution, the performance of PSCs in the rooftop field test, exposed to real weather conditions is evaluated. The 1 cm² single‐junction devices, with an initial average power conversion efficiency of 18.5% are tracked outdoors in maximum power point over several weeks. In parallel, irradiance and air temperature are recorded, allowing us to correlate outside factors with generated power. To get more insight into outdoor device performance, a comprehensive set of laboratory measurements under different light intensities (10% to 120% of AM1.5) and temperatures is performed. From these results, a low power temperature coefficient of ?0.17% K^?1 is extracted in the temperature range between 25 and 85 °C. By incorporating these temperature‐ and light‐dependent PV parameters into the energy yield model, it is possible to correctly predict the generated energy of the devices, thus validating the energy yield model. In addition, degradation of the tested devices can be tracked precisely from the difference between measured and modelled power.     

Patterns of host–parasite associations in tropical lice and their passerine hosts in Cameroon

Coevolutionary processes that drive the patterns of host–parasite associations can be deduced through congruence analysis of their phylogenies. Feather lice and their avian hosts have previously been used as typical model systems for congruence analysis; however, such analyses are strongly biased toward nonpasserine hosts in the temperate zone. Further, in the Afrotropical region especially, cospeciation studies of lice and birds are entirely missing. This work supplements knowledge of host–parasite associations in lice using cospeciation analysis of feather lice (genus Myrsidea and the Brueelia complex) and their avian hosts in the tropical rainforests of Cameroon. Our analysis revealed a limited number of cospeciation events in both parasite groups. The parasite–host associations in both louse groups were predominantly shaped by host switching. Despite a general dissimilarity in phylogeny for the parasites and hosts, we found significant congruence in host–parasite distance matrices, mainly driven by associations between Brueelia lice and passerine species of the Waxbill (Estrildidae) family, and Myrsidea lice and their Bulbul (Pycnonotidae) host species. As such, our study supports the importance of complex biotic interactions in tropical environments.     

Cloning and Characterization of a Gene (mspA) Encoding the Major Sheath Protein of Treponema maltophilum ATCC 51939T

The major sheath protein-encoding gene (mspA) of the oral spirochete Treponema maltophilum ATCC 51939^T was cloned by screening a genomic library with an anti-outer membrane fraction antibody. The mspA gene encodes a precursor protein of 575 amino acids with a predicted molecular mass of 62.3 kDa, including a signal peptide of 19 amino acids. The native MspA formed a heat-modifiable, detergent- and trypsin-stable complex which is associated with the outer membrane. Hybridization with an mspA-specific probe showed no cross-reactivity with the msp gene from Treponema denticola.