An early record of Meloidogyne fallax from Ireland

Root-knot nematodes, Meloidogyne spp., cause huge economic losses worldwide. Currently, three Meloidogyne spp. are present on the quarantine A2 list of EPPO, M. chitwoodi, M. fallax and M. enterolobii. As a quarantine organism, M. fallax has been detected in England and Northern Ireland on sport turf in 2011, and in England on leek in 2013. However, its presence in Ireland has probably been overlooked since 1965, when Mr. John F. Moore and Dr. Mary T. Franklin had detected a new Meloidogyne species for that time. While the relevant data was recorded and a preliminary manuscript describing the species was prepared but never submitted for publication, and together with the original slides, pictures and drawings, it was restudied recently. We compared the population of Irish Meloidogyne sp. to other similar Meloidogyne spp. Careful observation and comparison shows that it belongs to M. fallax. The characters found to be common for Irish Meloidogyne sp. and M. fallax are female stylet length (14.6 mu m) with oval to rounded basal knobs, oval shaped perineal pattern with moderately high dorsal arch, slender stylet in males (18.5 mu m) with set off and rounded basal knobs, slightly set off male head with one post-labial annule and incomplete transverse incisures, and second-stage juveniles with large and rounded stylet basal knobs, and a gradually tapering tail (46.9 mu m) with a broadly rounded tip and a clearly delimitated smooth hyaline part sometimes marked by constrictions (12.9 mu m). The host test and gall formation also correspond to M. fallax. The identification could not be additionally supported by molecular analysis, as we were unable to extract DNA from the old permanent slides. Nevertheless, our study reveals that the Meloidogyne species detected in Ireland in 1965 belongs to M. fallax

A review of the correlation of tergites, sternites, and leg pairs in diplopods

In some arthropods there is a discrepancy in the number of dorsal tergites compared to the number of ventral sternites and leg pairs. The posterior tergites of the Diplopoda (millipedes) each cover two sternites and two pairs of legs. This segment arrangement is called diplosegmentation. The molecular nature of diplosegmentation is still unknown. There are even conflicting theories on the way the tergites and sternites/leg pairs should be correlated to each other. The different theories are based either on embryological analyses or on studies of the adult morphology and turned out to be not compatible with each other. We have previously used the expression patterns of segmentation genes in the pill millipede Glomeris marginata (Myriapoda: Diplopoda) to study millipede segmentation. Here we review the existing models on the alignment of tergites and leg pairs in millipedes with special emphasis on the implications the gene expression data have on the debate of tergite and leg pair assignment in millipedes. The remarkable outcome of the gene expression analysis was that (1) there is no coupling of dorsal and ventral segmentation and, importantly, that (2) the boundaries delimiting the tergites do neither correlate to the embryonic boundaries of the dorsal embryonic segments nor to the boundaries of the ventral embryonic segments. Using these new insights, we critically reinvestigated the correlation of tergites, sternites, and leg pairs in millipedes. Our model, which takes into account that the tergite boundaries are different from the dorsal embryonic segment boundaries, provides a solution of the problem of tergite to sternite/leg pair correlation in basal milipedes with non-fused exoskeletal elements and also has implications for derived species with exoskeletal rings. Moreover, lack of coupling of dorsal and ventral segmentation may also explain the discrepancy in numbers of dorsal tergites and ventral leg pairs seen in some other arthropods

Expression of collier in the premandibular segment of myriapods: support for the traditional Atelocerata concept or a case of convergence?

<p>Abstract</p> <p>Background</p> <p>A recent study on expression and function of the ortholog of the <it>Drosophila collier </it>(<it>col</it>) gene in various arthropods including insects, crustaceans and chelicerates suggested a <it>de novo </it>function of <it>col </it>in the development of the appendage-less intercalary segment of insects. However, this assumption was made on the background of the now widely-accepted Pancrustacea hypothesis that hexapods represent an in-group of the crustaceans. It was therefore assumed that the expression of <it>col </it>in myriapods would reflect the ancestral state like in crustaceans and chelicerates, i.e. absence from the premandibular/intercalary segment and hence no function in its formation.</p> <p>Results</p> <p>We find that <it>col </it>in myriapods is expressed at early developmental stages in the same anterior domain in the head, the parasegment 0, as in insects. Comparable early expression of <it>col </it>is not present in the anterior head of an onychophoran that serves as an out-group species closely related to the arthropods.</p> <p>Conclusions</p> <p>Our findings suggest either that i) the function of <it>col </it>in head development has been conserved between insects and myriapods, and that these two classes of arthropods may be closely related supporting the traditional Atelocerata (or Tracheata) hypothesis; or ii) alternatively <it>col </it>function could have been lost in early head development in crustaceans, or may indeed have evolved convergently in insects and myriapods.</p

Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam

Recently, the extremely sensitive torsion-rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton-to-electron mass ratio over cosmological time scales. In order to improve this constraint, laboratory data of increased accuracy will be required. Here, we explore the possibility for performing high-resolution spectroscopy on methanol in a Stark-deflected molecular beam. We have calculated the Stark shift of the lower rotational levels in the ground torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to simulate trajectories through a typical molecular beam resonance setup. Furthermore, we have determined the efficiency of non-resonant multi-photon ionization of methanol molecules using a femtosecond laser pulse. The described setup is in principle suited to measure microwave transitions in CH3OH at an accuracy below 10^{-8}

The Sit-to-Stand Movement recovery after stroke and objective assessment

The Sit-to-Stand (STS) movement can be described as the change in body posture from a sitting to standing position. In more biomechanical terms, it can be defined as a transitional movement to the upright posture requiring movement of the center of mass from a stable to a less stable position over extended lower extremities. The STS movement is an important skill because it is related to functioning and mobility, and is a prerequisite for walking. The execution of the STS movement varies within and between persons, because many factors influence the way how people perform an STS movement, e.g. seat height, arm rests, feet position, age, and lower extremity muscle strength. Literature indicates that also health condition, e.g. neuromuscular disorders, joint disorders and stroke, can result in specific changes in the execution of the STS movement

Mitochondrial coding genome analysis of tropical root-knot nematodes (Meloidogyne) supports haplotype based diagnostics and reveals evidence of recent reticulate evolution

The polyphagous parthenogenetic root-knot nematodes of the genus Meloidogyne are considered to be the most significant nematode pest in sub-tropical and tropical agriculture. Despite the crucial need for correct diagnosis, identification of these pathogens remains problematic. The traditionally used diagnostic strategies, including morphometrics, host-range tests, biochemical and molecular techniques, now appear to be unreliable due to the recently-suggested hybrid origin of root-knot nematodes. In order to determine a suitable barcode region for these pathogens nine quickly-evolving mitochondrial coding genes were screened. Resulting haplotype networks revealed closely related lineages indicating a recent speciation, an anthropogenic-aided distribution through agricultural practices, and evidence for reticulate evolution within M. arenaria. Nonetheless, nucleotide polymorphisms harbor enough variation to distinguish these closely-related lineages. Furthermore, completeness of lineage sorting was verified by screening 80 populations from widespread geographical origins and variable hosts. Importantly, our results indicate that mitochondrial haplotypes are strongly linked and consistent with traditional esterase isozyme patterns, suggesting that different parthenogenetic lineages can be reliably identified using mitochondrial haplotypes. The study indicates that the barcode region Nad5 can reliably identify the major lineages of tropical root-knot nematodes

Achieving E-learning with IMS Learning Design - Workflow Implications at the Open University of the Netherlands

Please refer to the original article in: Westera, W., Brouns, F., Pannekeet, K., Janssen, J., & Manderveld, J. (2005). Achieving E-learning with IMS Learning Design - Workflow Implications at the Open University of the Netherlands. Educational Technology & Society, 8 (3), 216-225. (URL: http://www.ifets.info/others/abstract.php?art_id=570)This paper uses the Open University of the Netherlands as an instructive case for the introduction of e-learning based on the IMS Learning Design specification (IMS LD). The IMS LD specification, as approved by the IMS Global Learning Consortium in 2003, enables the specification and encoding of learning scenarios that describe any design of a teaching-learning process, i.e. support events, exchanges of projects, interactions and communications between participants. In 2004, after several years of small-scale pilots, the Open University of the Netherlands launched IMS LD-based online learning in an operational setting (over 3000 students). Rather than technology, the paper describes the implications for the workflow. The paper explains the processes involved with both IMS LD-based course creation and course delivery. Preliminary findings establish severe inconveniences for developers in the process of course creation, due to immature IMS LD tooling. Tutors, however, comment positively on course delivery, in particular on the way IMS LD supports course logistics, i.e. the arrangement of course runs, the control of student groups, tracking the students’ progress and the support to the exchange of messages and papers. Even though the applied IMS LD-models were deliberately kept simple with respect to interactions and methods, students for their part appreciated the online courses, in particular the functionalities typically enabled by IMS LD, like personalised flow, tailored feedback and portfolios. In sum, taking for granted the immature tooling, the IMS LD specification seems to work in large-scale operational settings