Identification of quantitative trait loci for resistance to Verticillium wilt and yield parameters in hop (Humulus lupulus L.)

Verticillium wilt (VW) can cause substantial yield loss in hop particularly with the outbreaks of the lethal strain of Verticillium albo-atrum. To elucidate genetic control of VW resistance in hop, an F₁ mapping population derived from a cross of cultivar Wye Target, with the predicted genetic basis of resistance, and susceptible male breeding line BL2/1 was developed to assess wilting symptoms and to perform QTL mapping. The genetic linkage map, constructed with 203 markers of various types using a pseudo-testcross strategy, formed ten major linkage groups (LG) of the maternal and paternal maps, covering 552.98 and 441.1 cM, respectively. A significant QTL for VW resistance was detected at LOD 7 on a single chromosomal region on LG03 of both parental maps, accounting for 24.2–26.0 % of the phenotypic variance. QTL analysis for alpha-acid content and yield parameters was also performed on this map. QTLs for these traits were also detected and confirmed our previously detected QTLs in a different pedigree and environment. The work provides the basis for exploration of QTL flanking markers for possible use in marker-assisted selection.     

Computer-guided surgery for gastric carcinoma

Lymphadenectomy offers the only hope for cure when lymph nodes are involved. In gastric cancer, three approaches have been pursued to preoperatively predict node status in individual patients, modern radiological imaging techniques, sentinel node and technique that uses a computerized database of information to convert a large amount of information and experience to a treatment decision for an individual patient. The aim of this study was to evaluate accuracy in preoperative prediction of lymph node status in selected patients with the help of computer analysis for stage-appropriate surgery. With the help of computer programs Win Estimate and Microsoft Access, we constructed an artificial neural network that calculated a statistical prediction of nodal status in an observed patient with preoperatively gathered data. In 110 patients who have undergone R0 resection with D2 lymphadenectomy, the differences between the individual results generated by artificial neural network calculation and the actual data were compared. The accuracy of computerized predictions of N0 stage for study group is 91%, sensitivity 94% and specificity 87%. The results of accuracy of computerized preoperative prediction of N2 stage are 88%, with sensitivity 94% and specificity 88%. Preoperative analyses of patient data and tumour characteristics offers a rational approach to individualizing tumour therapy where the extent of lymph node dissection is tailored to the type, site, and stage of the tumour, thereby minimizing the disadvantages associated with the extensive operative procedure.     

Endosymbiotic bacteria nodulating a new endemic lupine Lupinus mariae-josephi from alkaline soils in Eastern Spain represent a new lineage within the Bradyrhizobium genus

Lupinus mariae-josephi is a recently described endemic Lupinus species from a small area in Eastern Spain where it thrives in soils with active lime and high pH. The L. mariae-josephi root symbionts were shown to be very slow-growing bacteria with different phenotypic and symbiotic characteristics from those of Bradyrhizobium strains nodulating other Lupinus. Their phylogenetic status was examined by multilocus sequence analyses of four housekeeping genes (16S rRNA, glnII, recA, and atpD) and showed the existence of a distinct evolutionary lineage for L. mariae-josephi that also included Bradyrhizobium jicamae. Within this lineage, the tested isolates clustered in three different sub-groups that might correspond to novel sister Bradyrhizobium species. These core gene analyses consistently showed that all the endosymbiotic bacteria isolated from other Lupinus species of the Iberian Peninsula were related to strains of the B. canariense or B. japonicum lineages and were separate from the L. mariae-josephi isolates. Phylogenetic analysis based on nodC symbiotic gene sequences showed that L. mariae-josephi bacteria also constituted a new symbiotic lineage distant from those previously defined in the genus Bradyrhizobium. In contrast, the nodC genes of isolates from other Lupinus spp. from the Iberian Peninsula were again clearly related to the B. canariense and B. japonicum bv. genistearum lineages. Speciation of L. mariae-josephi bradyrhizobia may result from the colonization of a singular habitat by their unique legume host.     

Development of transcript-associated microsatellite markers for diversity and linkage mapping studies in hop (<Emphasis Type="Italic">Humulus lupulus</Emphasis> L.)

Data mining of gene sequences available from various projects dealing with the development of expressed sequence tags (ESTs) can contribute to the discovery of new microsatellite markers. Our aim was to develop new microsatellite markers in hop isolated from an enriched cDNA library and from coding GenBank sequences and to test their suitability in hop diversity studies and for construction of a linkage map. In a set of 614 coding GenBank sequences, 72 containing microsatellites were found (11.7%); the most frequent were trinucleotide repeats (54.0%) followed by dinucleotide repeats (34.5%). Additionally, 11 sequences containing microsatellites were isolated from an enriched cDNA library. A total of 34 primer pairs were designed, 29 based on GenBank sequences and five on sequences from the cDNA enriched library. Twenty-seven (79.4%) coding microsatellites were successfully amplified and used in diversity and linkage mapping studies. Eleven primer pairs amplified 12 coding microsatellite loci suitable for mapping and were placed on female and male linkage maps. We were able to extend previous simple sequence repeat (SSR) female, male and integral maps by 38.8, 25.8 and 40.0 cM, respectively. In the diversity study, 36 diverse hop genotypes were analyzed. Twenty-four coding microsatellites were polymorphic, 17 showing co-dominant behavior and 7 primer pairs amplifying three or more bands in some hop genotypes. Altogether, 143 microsatellite DNA fragments were amplified and they revealed a clear separation of hop genotypes according to geographical region, use or breeding history. In addition, a discussion and comparison of results with other plant coding/EST SSR studies is presented. Our results showed that these microsatellite markers can enhance hop diversity and linkage mapping studies and are a comparable marker system to non-coding SSRs.     

Synthesis and antimalarial activities of novel 3,3,6,6-tetraalkyl-1,2,4,5-tetraoxanes

The oxidative system H2O2/fluorinated alcohol (TFE, HFIP) was used for direct acid- and MeReO3-catalyzed synthesis of 1,2,4,5-tetraoxanes from cyclic (C6, C7, and C12) and acyclic ketones. The influence of ring size and alkyl chain length were studied and antimalarial activities of synthetic 3,3,6,6-tetraalkyl-1,2,4,5-tetraoxanes were determined. Variations in their antimalarial activities were significant, although they share similar electrochemical properties of the peroxide bond.     

Palomena prasina (Hemiptera: Pentatomidae) vibratory signals and their tuning with plant substrates

Palomena prasina is interesting for the study of vibrational communication within the Pentatomid subfamily Pentatominae, because its host range is limited to woody plants, unlike the better known Nezara viridula, whose vibrational communication is commonly used as a model for the whole family. The vibrational repertoire of P. prasina was described several decades ago and is redescribed in this paper using modern methods for non-contact vibration recording. Additionally, we hypothesized that this species has retained the capacity for signal frequency variation necessary for tuning to resonance properties of various host plants of Pentatominae, but if the signals are emited in the absence of mechanical feedback, they are tuned more specifically to their native acoustic environment — woody plants. By recording live bugs signalling on different substrates and comparing spectral properties of their signals among substrates, we found that there is a match between the signals emitted on a woody branch and those emitted on a non-resonant surface, while spectral properties of signals emitted on herbaceous plants differ. Our findings provide evidence in support of the signal tuning hypothesis and shed further light on the crucial role of substrate in vibrational communication of insects.