Broad Defense Research Articles

Brood Guarding by an Adult Parasitoid Reduces Cannibalism of Parasitoid-Attacked Conspecifics by a Caterpillar Host

Adult female bethylid parasitoids (Hymenoptera: Bethylidae) commonly guard their offspring until they develop into later immature stages to protect them from competing parasitoids and predators. Another possible mortality factor is from caterpillar larvae that cannibalize parasitized conspecific larvae. This study determined the effect of brood guarding on the occurrence of host cannibalism by using a brood guarding bethylid parasitoid Goniozus legneri and a non-guarding braconid parasitoid Habrobracon gelechiae (Hymenoptera: Braconidae), both are gregarious ectoprasitoids that attack the obliquebanded leafroller Choristoneura rosaceana (Lepidoptera: Tortricidae). When a C. rosaceana larva parasitized by G. legneri was presented to a live conspecific larva, the frequency of cannibalism on the parasitized conspecific was lower in the presence than in the absence of a guarding female G. legneri. In contrast, when a C. rosaceana larva parasitized by H. gelechiae was presented to a live conspecific larva, the presence or absence of H. gelechiae did not affect cannibalism frequency. Cannibals did not gain a fitness advantage in terms of larval survival, developmental time, or body mass of developed pupae; therefore, cannibalism by the host larva may be a group defense against increased parasitism in subsequent population generations. We suggest that brood guarding by parasitoids can act as a broad defense strategy to protect offspring from the cannibalism of parasitized conspecifics by the host larvae.

A GUIDE-POST FOR THE SECOND DECADE OF THE BULLETIN OF THE SLOVENIAN ARMED FORCES

A GUIDE-POST FOR THE SECOND DECADE OF THE BULLETIN OF THE SLOVENIAN ARMED FORCES

The pathogenic white-rot fungus Heterobasidion parviporum triggers non-specific defence responses in the bark of Norway spruce

Norway spruce [Picea abies (L.) Karst.] is one of the economically most important conifer species in Europe. The major pathogen on Norway spruce is Heterobasidion parviporum (Fr.) Niemelä & Korhonen. To achieve a better understanding of Norway spruce's defence mechanisms, transcriptional responses in bark to H. parviporum infection were compared with the response to wounding using cDNA-amplified fragment length polymorphism. The majority of the recovered transcript-derived fragments (TDFs) showed a similar expression pattern for infection and wounding treatment, although inoculated samples showed an enhanced reaction. Genes related to systemic acquired resistance, e.g., PR1, accumulated after H. parviporum infection. Simultaneously, several transcripts involved in various aspects of jasmonic acid (JA)- and ethylene (ET)-mediated signalling accumulated. Genes involved in the ubiquitin/proteasome system were also regulated. Expression patterns have been confirmed by quantitative polymerase chain reaction. The expression patterns of the isolated TDFs suggest that infection with H. parviporum in Norway spruce induces a broad defence, with many similarities to non-specific defence responses in angiosperms. The parallel induction of salicylic acid- and JA/ET-mediated pathways implies spatially separated responses in different cell layers, with and without hyphal contact. A set of TDFs were analysed in an independent experiment with unrelated material treated with wounding or with inoculation with H. parviporum or Phlebiopsis gigantea, verifying the original observations and underlining the non-specific defence responses. In addition, our data suggest that rerouting of carbon in secondary metabolism is an integral part of Norway spruce induced defence. We report the sequences of three 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase genes (PaDAHP1, PaDAHP2 and PaDAHP3) and their relative expression in response to wounding and infection with H. parviporum and P. gigantea. The results clearly indicate differential regulation of the three DAHPs in the induced defence responses in Norway spruce. This study gives insights into the central mechanisms in the induced defences in Norway spruce.

Heterobasidionspp, triggers non-specific defence responses in bark of Norway spruce

Norway spruce [Picea abies (L.) Karst.] is one of the economically most important conifer species in Europe. The major pathogen on Norway spruce is Heterobasidion parviporum (Fr.) Niemela & Korhonen. The completed genome sequence of H. irregulare opens up new possibilities to understand the interactions between Heterobasidion spp. and spruce. However to date there are no completed genome sequencing projects of conifer genomes available for complementing studies. To achieve a better understanding of induced transcriptional defence responses in Norway spruce upon Heterobasidion spp. attack, we compared transcriptional responses in bark to H. parviporum infection to the response to wounding using cDNA-AFLP and transcriptome sequencing. In an initial study bark samples were harvested at 3, 7 and 14 days post inoculation (dpi) and untreated bark was used as negative control. About 2500 transcribed derived fragments (TDFs) generated by cDNA-AFLP were screened. 199 TDFs were investigated further based on band intensity in the inoculated bark in relation to either untreated bark or wounded bark. Out of these, 119 TDFs had a putative homology and a consistent band intensity pattern between replications. A majority of these TDFs showed homology to genes known to associate with defence e.g. 3-deoxy-d-arabino-heptulosonate 7-phosphate synthetase (DAHP), Pathogenesis-related protein 1 (PR1), Lipoxygenase (LOX), ACC-synthase (ACS), ACC-oxidase (ACO) and Jasmonate ZIM-domain 1 (JAZ1). Many of these are found in Salicylic acid- or Jasmonic acid/ethylene-signalling pathways. The majority of the TDFs showed a similar expression pattern for all treatments but samples inoculated with H. parviporum generally showed an enhanced reaction (induction/repression) compared to wounding alone. Expression patterns were confirmed by qPCR in material treated with wounding and inoculation with H. parviporum or Phlebiopsis gigantea. Our data suggest that infection with H. parviporum in Norway spruce induces a broad defence, with many similarities to non-specific defence responses in angiosperms. Additionally signs of reallocation of carbon from primary to secondary metabolism were evident. With this information at hand we analysed four Norway spruce genotypes with either high or low susceptibility to Heterobasidion spp. [1] sampled 0, 5, 15 and 28 dpi with H. annosum. The bark phenol-composition was profiled in each sample. The 500,000 454-reads were assembled into 17,228 contigs that assembled in 14,364 putative transcript units (PTU) using the sequence assembler software Newbler™ (http://www.454.com). The assembled reference file was annotated with the software Blast2Go and the PTUs were submitted to differential expression analysis. Data on associations between gene expression levels and phenol composition in bark upon H. annosum inoculation and level of susceptibility will be presented.

Preventive Antibiotics in Stroke Study: Rationale and Protocol for a Randomised Trial

Stroke is a leading cause of death worldwide. Fever after stroke is a strong predictor of a poor outcome. Infections occur in up to 40% of patients with stroke and have also been associated with poor outcomes. Preventive antibiotic therapy lowers the infection rates in patients after stroke, as shown in a recent meta-analysis of randomised studies. Phase III trials evaluating the effect of antibiotic prophylaxis on clinical outcomes in sufficient numbers of patients with stroke have, however, not been performed to date. Ceftriaxone, an off-patent medicine, is an antibiotic with a broad defence against the bacteria that cause the most common infections after stroke. Preventive antibiotic therapy with ceftriaxone may potentially reduce poor outcome after acute stroke and, therefore, a randomised clinical trial is warranted. The aim of the present study is to investigate whether the preventive use of the antibiotic ceftriaxone improves functional outcome in patients with stroke. We will conduct a multicentre prospective, randomised, open-label, blinded end point trial of standard care with preventive ceftriaxone treatment and compare it with standard care without preventive ceftriaxone. Adult patients with stroke (both ischaemic and haemorrhagic) and a score ≥ 1 on the National Institutes of Health Stroke Scale will be included. The 3200 patients will be randomly assigned to two groups of 1600 patients. One group will receive standard care and ceftriaxone at a dose of 2 g, given every 24 h intravenously for four-days, and the other group will receive stroke-unit care without preventive antibiotic treatment. The primary end point will be functional outcome at a three-month follow-up on the modified Rankin Scale, dichotomised as a favourable outcome (0-2) or an unfavourable outcome (3-6). Secondary outcome measures will be death rate at discharge and three-months, infection rate during hospital admission, length of hospital admission, volume of poststroke care, use of antibiotics during the three-month follow-up, functional outcome using the full ordinal scoring range of the modified Rankin Scale, quality-adjusted life years and costs.

Subgroup 4 R2R3-MYBs in conifer trees: gene family expansion and contribution to the isoprenoid- and flavonoid-oriented responses.

Transcription factors play a fundamental role in plants by orchestrating temporal and spatial gene expression in response to environmental stimuli. Several R2R3-MYB genes of the Arabidopsis subgroup 4 (Sg4) share a C-terminal EAR motif signature recently linked to stress response in angiosperm plants. It is reported here that nearly all Sg4 MYB genes in the conifer trees Picea glauca (white spruce) and Pinus taeda (loblolly pine) form a monophyletic clade (Sg4C) that expanded following the split of gymnosperm and angiosperm lineages. Deeper sequencing in P. glauca identified 10 distinct Sg4C sequences, indicating over-represention of Sg4 sequences compared with angiosperms such as Arabidopsis, Oryza, Vitis, and Populus. The Sg4C MYBs share the EAR motif core. Many of them had stress-responsive transcript profiles after wounding, jasmonic acid (JA) treatment, or exposure to cold in P. glauca and P. taeda, with MYB14 transcripts accumulating most strongly and rapidly. Functional characterization was initiated by expressing the P. taeda MYB14 (PtMYB14) gene in transgenic P. glauca plantlets with a tissue-preferential promoter (cinnamyl alcohol dehydrogenase) and a ubiquitous gene promoter (ubiquitin). Histological, metabolite, and transcript (microarray and targeted quantitiative real-time PCR) analyses of PtMYB14 transgenics, coupled with mechanical wounding and JA application experiments on wild-type plantlets, allowed identification of PtMYB14 as a putative regulator of an isoprenoid-oriented response that leads to the accumulation of sesquiterpene in conifers. Data further suggested that PtMYB14 may contribute to a broad defence response implicating flavonoids. This study also addresses the potential involvement of closely related Sg4C sequences in stress responses and plant evolution.

An Outlook on the Localisation and Structure-Function Relationships of R Proteins in Solanum

The co-evolution of plants and plant-pathogens shaped a multi-layered defence system in plants, in which Resistance proteins (R proteins) play a significant role. A fundamental understanding of the functioning of these R proteins and their position in the broader defence system of the plant is essential. Sub-project 3 of the BIOEXPLOIT programme studies how R proteins are activated upon effector recognition and how recognition is conveyed in resistance signalling pathways, using the solanaceous R proteins Rx1 (from S. tuberosum spp. andigena; conferring extreme resistance against Potato Virus X), I-2 (from S. lycopersicon; mediating resistance to Fusarium oxysporum) and Mi-1.2 (from S. lycopersicon; conferring resistance to Meloidogyne incognita) as model systems. The results obtained in this project will serve as a model for other R proteins and will be translated to potential applications or alternative strategies for disease resistance. These include the modification of the recognition specificity of R proteins with the aim to obtain broad spectrum resistance to major pathogens in potato.

Keeping Things Quiet

Among its many functions, RNA silencing provides broad cellular defense against viruses in many plant and animal species. To perform defense functions, microRNAs (miRNAs) arm an RNA-induced silencing complex (RISC), which either degrades messenger RNA or inhibits its translation. Triboulet et al . show that proteins responsible for generating miRNA potently inhibit human immunodeficiency virus-type 1 (HIV-1) in naturally infected cells and that HIV-1 counters this by down-modulating the expression of selected cellular miRNAs to favor replication. Targeting the miRNA processing pathway may offer a strategy for activating latent viral reservoirs, which remain barriers to eliminating chronic HIV-1 infection. R. Triboulet, B. Mari, Y.-L. Lin, C. Chable-Bessia, Y. Bennasser, K. Lebrigand, B. Cardinaud, T. Maurin, P. Barbry, V. Baillat, J. Reynes, P. Corbeau, K.-T. Jeang, M. Benkirane, Suppression of microRNA-silencing pathway by HIV-1 during virus replication. Science 315 , 1579-1582 (2007). [Abstract] [Full Text]

‘The Privileged Few’ and the Classification of Henwood v Harrison

This article considers the treatment of one nineteenth century English defamation decision, Henwood v Harrison, in light of Michel Foucault’s understanding of the construction of discourses. In particular, the processes of classification applied to the decision are examined. That is, the manner in which later barristers, judges, commentators and digest compilers categorised Henwood v Harrison is argued to be an example of an internal discursive control. The treatment of the decision as representing a precedent for either a broad privilege defence to defamatory statements or narrower defences of comment or qualified privilege can be seen as both representing the arbitrary nature of classification and as indicative of the changes taking place in English common law at the time.

Beyond reason: A feminist theory of ethics for journalists

In ethical decision making, emotion can be superior to reason, although historically emotion has been generally considered inferior to reason. A single concept serves as the principle for emotional development and decision making—empathy. For journalists, legal questions are often easy, ethical questions hard. “Newsworthiness” gives journalists a broad defense against privacy suits. Photographs have caused much controversy. As this article shows, usually journalists win suits involving photographs. Still, ethical questions persist. In the heat of time pressure, emotivism provides a fairly simple and accurate method of deciding whether to use photographs, and this article provides steps for applying emotivism.

Aerospace defense requirements in post‐Soviet Russia

Abstract Throughout 1989–1991, the officer corps of the Soviet Air Defense Forces, the PVO, held a lengthy discussion of the missions and roles of air defense in a changing strategic environment. As a result of this discussion, the Soveit PVO mission was changed from one of broad perimeter defense to more limited missions of selective area and point defense against attacks from air and space. This change would require increased mobility and modernization; however, the demise of the Soviet Union and continuing economic disarray makes such a transition to a modernized air defense nearly impossible. It may be the desire to achieve such modernization that led the Russian government in January 1992 to seek cooperation with the United States in a “Global Protection System.”.