Three new species of <Emphasis Type="Italic">Luetzelburgia</Emphasis> (<Emphasis Type="Italic">Leguminosae</Emphasis>, <Emphasis Type="Italic">Papilionoideae</Emphasis>) from the caatinga of Bahia,Brazil and an identification key to all species of the genus

Three new species of the Brazilian genus Luetzelburgia Harms (Leguminosae, Papilionoideae, Sophoreae sensu lato (Vataireoid clade)) are described and illustrated under the names Luetzelburgia harleyi D. Cardoso, L. P. Queiroz &; H. C. Lima, L. neurocarpa D. Cardoso, L. P. Queiroz &; H. C. Lima and L. purpurea D. Cardoso, L. P. Queiroz &; H. C. Lima. All three occur in the caatinga vegetation of the State of Bahia, Eastern Brazil. A discussion of the morphological characters distinguishing the new species from their close relatives, as well as an identification key to all known species of Luetzelburgia, are presented.     

Identification of a Low Digestibility δ-Conglutin in Yellow Lupin (Lupinus luteus L.) Seed Meal for Atlantic Salmon (Salmo salar L.) by Coupling 2D-PAGE and Mass Spectrometry

The need of quality protein in the aquaculture sector has forced the incorporation of alternative plant proteins into feeding diets. However, most plant proteins show lower digestibility levels than fish meal proteins, especially in carnivorous fishes. Manipulation of protein content by plant breeding can improve the digestibility rate of plant proteins in fish, but the identification of low digestibility proteins is essential. A reduction of low digestibility proteins will not only increase feed efficiency, but also reduce water pollution. Little is known about specific digestible protein profiles and/or molecular identification of more bioavailable plant proteins in fish diets. In this study, we identified low digestibility L. luteus seed proteins using Atlantic salmon (Salmo salar) crude digestive enzymes in an in vitro assay. Low digestibility proteins were identified by comparing SDS-PAGE banding profiles of digested and non-digested lupin seed proteins. Gel image analysis detected a major 12 kDa protein band in both lupin meal and protein isolate digested products. The 12 kDa was confirmed by 2D-PAGE gels and the extracted protein was analyzed with an ion trap mass spectrometer in tandem mass mode. The MS/MS data showed that the 12 kDa low digestibility protein was a large chain δconglutin, a common seed storage protein of yellow lupin. Comparison of the protein band profiles between lupin meal and protein isolates showed that the isolatation process did not affect the low digestibility of the 12 kDa protein.     

The distribution of transgene insertion sites in barley determined by physical and genetic mapping

The exact site of transgene insertion into a plant host genome is one feature of the genetic transformation process that cannot, at present, be controlled and is often poorly understood. The site of transgene insertion may have implications for transgene stability and for potential unintended effects of the transgene on plant metabolism. To increase our understanding of transgene insertion sites in barley, a detailed analysis of transgene integration in independently derived transgenic barley lines was carried out. Fluorescence in situ hybridization (FISH) was used to physically map 23 transgene integration sites from 19 independent barley lines. Genetic mapping further confirmed the location of the transgenes in 11 of these lines. Transgene integration sites were present only on five of the seven barley chromosomes. The pattern of transgene integration appeared to be nonrandom and there was evidence of clustering of independent transgene insertion events within the barley genome. In addition, barley genomic regions flanking the transgene insertion site were isolated for seven independent lines. The data from the transgene flanking regions indicated that transgene insertions were preferentially located in gene-rich areas of the genome. These results are discussed in relation to the structure of the barley genome.     

An efficient method for the physical mapping of transgenes in barley using in situ hybridization.

The genetic transformation of crops by particle bombardment and Agrobacterium tumefaciens systems have the potential to complement conventional plant breeding programmes. However, before deployment, transgenic plants need to be characterized in detail, and physical mapping is an integral part of this process. Therefore, it is important to have a highly efficient method for transgene detection by fluorescence in situ hybridization (FISH). This study describes a new approach, which provides efficient control of probe length and labelling, both of which play an important role in in situ hybridization of transgenes. The approach is based on reducing the size of the plasmid prior to labelling by nick translation, rather than using the whole or linearized plasmid, or varying the amounts of DNaseI in the nick translation mixture. This provided much more efficient labelling of the probe, which yielded optimal hybridization. minimal fluorescent background, and accurate physical location of the transgene.     

An RFLP map of diploid Hordeum bulbosum L. and comparison with maps of barley (H. vulgare L.) and wheat (Triticum aestivum L.)

This paper describes the first extensive genetic map of Hordeum bulbosum, the closest wild relative of cultivated barley. H. bulbosum is valuable for haploid production in barley breeding, and because of desirable agronomic characteristics, it also has potential for trait introgression into barley. A H. bulbosum map will assist introgression and provide a basis for the identification of QTLs for crossability with barley and other potentially useful genes. The present study used a population of 111 individuals from a PB1×PB11 cross to develop a genetic linkage map of diploid H. bulbosum (2n=2x=14) based on barley, wheat and other ”anchor” cereal RFLP markers previously mapped in other species. Because of the cross-pollinating and highly polymorphic nature of H. bulbosum, up to four alleles showed segregation at any one locus, and five different segregation types were found. This enabled maps to be developed for the PB1 and PB11 parents, as well as a combined map. In total, 136 RFLP loci were mapped with a marker coverage of 621 cM. The markers were generally colinear with barley but H. bulbosum had less recombination in the centromeric regions and similar or more in the distal regions. Cytological studies on pollen mother cells at metaphase-I showed marked distal localization of chiasmata and a frequency consistent with the genetic map length. This study showed that H. bulbosum was highly polymorphic, making it suitable for trait analysis and supplementing maps of barley. Received: 20 November 2000 / Accepted: 5 January 2001     

The chicken or the egg? Plastome evolution and an independent loss of the inverted repeat in papilionoid legumes

The plastid genome (plastome), while surprisingly constant in gene order and content across most photosynthetic angiosperms, exhibits variability in several unrelated lineages. During the diversification history of the legume family Fabaceae, plastomes have undergone many rearrangements, including inversions, expansion, contraction and loss of the typical inverted repeat (IR), gene loss and repeat accumulation in both shared and independent events. While legume plastomes have been the subject of study for some time, most work has focused on agricultural species in the IR-lacking clade (IRLC) and the plant model Medicago truncatula. The subfamily Papilionoideae, which contains virtually all of the agricultural legume species, also comprises most of the plastome variation detected thus far in the family. In this study three non-papilioniods were included among 34 newly sequenced legume plastomes, along with 33 publicly available sequences, to assess plastome structural evolution in the subfamily. In an effort to examine plastome variation across the subfamily, approximately 20% of the sampling represents the IRLC with the remainder selected to represent the early-branching papilionoid clades. A number of IR-related and repeat-mediated changes were identified and examined in a phylogenetic context. Recombination between direct repeats associated with ycf2 resulted in intraindividual plastome heteroplasmy. Although loss of the IR has not been reported in legumes outside of the IRLC, one genistoid taxon was found to completely lack the typical plastome IR. The role of the IR and non-IR repeats in the progression of plastome change is discussed.     

Transient Superdiffusion and Long-Range Correlations in the Motility Patterns of Trypanosomatid Flagellate Protozoa

We report on a diffusive analysis of the motion of flagellate protozoa species. These parasites are the etiological agents of neglected tropical diseases: leishmaniasis caused by Leishmania amazonensis and Leishmania braziliensis, African sleeping sickness caused by Trypanosoma brucei, and Chagas disease caused by Trypanosoma cruzi. By tracking the positions of these parasites and evaluating the variance related to the radial positions, we find that their motions are characterized by a short-time transient superdiffusive behavior. Also, the probability distributions of the radial positions are self-similar and can be approximated by a stretched Gaussian distribution. We further investigate the probability distributions of the radial velocities of individual trajectories. Among several candidates, we find that the generalized gamma distribution shows a good agreement with these distributions. The velocity time series have long-range correlations, displaying a strong persistent behavior (Hurst exponents close to one). The prevalence of “universal” patterns across all analyzed species indicates that similar mechanisms may be ruling the motion of these parasites, despite their differences in morphological traits. In addition, further analysis of these patterns could become a useful tool for investigating the activity of new candidate drugs against these and others neglected tropical diseases.