Extreme heterochiasmy and nascent sex chromosomes in European tree frogs.

We investigated sex-specific recombination rates in Hyla arborea, a species with nascent sex chromosomes and male heterogamety. Twenty microsatellites were clustered into six linkage groups, all showing suppressed or very low recombination in males. Seven markers were sex linked, none of them showing any sign of recombination in males (r=0.00 versus 0.43 on average in females). This opposes classical models of sex chromosome evolution, which envision an initially small differential segment that progressively expands as structural changes accumulate on the Y chromosome. For autosomes, maps were more than 14 times longer in females than in males, which seems the highest ratio documented so far in vertebrates. These results support the pleiotropic model of Haldane and Huxley, according to which recombination is reduced in the heterogametic sex by general modifiers that affect recombination on the whole genome.

Range-Wide Sex-Chromosome Sequence Similarity Supports Occasional XY Recombination in European Tree Frogs (Hyla arborea).

In contrast with mammals and birds, most poikilothermic vertebrates feature structurally undifferentiated sex chromosomes, which may result either from frequent turnovers, or from occasional events of XY recombination. The latter mechanism was recently suggested to be responsible for sex-chromosome homomorphy in European tree frogs (Hyla arborea). However, no single case of male recombination has been identified in large-scale laboratory crosses, and populations from NW Europe consistently display sex-specific allelic frequencies with male-diagnostic alleles, suggesting the absence of recombination in their recent history. To address this apparent paradox, we extended the phylogeographic scope of investigations, by analyzing the sequences of three sex-linked markers throughout the whole species distribution. Refugial populations (southern Balkans and Adriatic coast) show a mix of X and Y alleles in haplotypic networks, and no more within-individual pairwise nucleotide differences in males than in females, testifying to recurrent XY recombination. In contrast, populations of NW Europe, which originated from a recent postglacial expansion, show a clear pattern of XY differentiation; the X and Y gametologs of the sex-linked gene Med15 present different alleles, likely fixed by drift on the front wave of expansions, and kept differentiated since. Our results support the view that sex-chromosome homomorphy in H. arborea is maintained by occasional or historical events of recombination; whether the frequency of these events indeed differs between populations remains to be clarified.

Successful Tree Planting, March 2002

Advance planning, proper species selection, site preparation, careful handling of tree seedlings, and a good weed control program will help assure a successful tree planting. A commitment to plant with care, is an important first step that leads to successful establishment of tree and shrub seedlings.

Biotic and abiotic variables show little redundancy in explaining tree species distributions

Abiotic factors such as climate and soil determine the species fundamental niche, which is further constrained by biotic interactions such as interspecific competition. To parameterize this realized niche, species distribution models (SDMs) most often relate species occurrence data to abiotic variables, but few SDM studies include biotic predictors to help explain species distributions. Therefore, most predictions of species distributions under future climates assume implicitly that biotic interactions remain constant or exert only minor influence on large-scale spatial distributions, which is also largely expected for species with high competitive ability. We examined the extent to which variance explained by SDMs can be attributed to abiotic or biotic predictors and how this depends on species traits. We fit generalized linear models for 11 common tree species in Switzerland using three different sets of predictor variables: biotic, abiotic, and the combination of both sets. We used variance partitioning to estimate the proportion of the variance explained by biotic and abiotic predictors, jointly and independently. Inclusion of biotic predictors improved the SDMs substantially. The joint contribution of biotic and abiotic predictors to explained deviance was relatively small (similar to 9%) compared to the contribution of each predictor set individually (similar to 20% each), indicating that the additional information on the realized niche brought by adding other species as predictors was largely independent of the abiotic (topo-climatic) predictors. The influence of biotic predictors was relatively high for species preferably growing under low disturbance and low abiotic stress, species with long seed dispersal distances, species with high shade tolerance as juveniles and adults, and species that occur frequently and are dominant across the landscape. The influence of biotic variables on SDM performance indicates that community composition and other local biotic factors or abiotic processes not included in the abiotic predictors strongly influence prediction of species distributions. Improved prediction of species' potential distributions in future climates and communities may assist strategies for sustainable forest management.

Matters Relating to a Forced Move of, Use of a Chemical Agent on and Withdrawal of Medication for Inmate Craig Gardner, 1994

Case Number 91-151 Craig Gardner, an inmate in the Iowa prison system, was the subject of a force move by correctional officers while incarcerated at the Iowa State Penitentiary (ISP). This action involved the use of a chemical agent. This investigation began as a review of the use of a chemical agent in a forced cell move on June 30, 1991.

The sigma factor AlgU (AlgT) controls exopolysaccharide production and tolerance towards desiccation and osmotic stress in the biocontrol agent Pseudomonas fluorescens CHA0.

A variety of stress situations may affect the activity and survival of plant-beneficial pseudomonads added to soil to control root diseases. This study focused on the roles of the sigma factor AlgU (synonyms, AlgT, RpoE, and sigma(22)) and the anti-sigma factor MucA in stress adaptation of the biocontrol agent Pseudomonas fluorescens CHA0. The algU-mucA-mucB gene cluster of strain CHA0 was similar to that of the pathogens Pseudomonas aeruginosa and Pseudomonas syringae. Strain CHA0 is naturally nonmucoid, whereas a mucA deletion mutant or algU-overexpressing strains were highly mucoid due to exopolysaccharide overproduction. Mucoidy strictly depended on the global regulator GacA. An algU deletion mutant was significantly more sensitive to osmotic stress than the wild-type CHA0 strain and the mucA mutant were. Expression of an algU'-'lacZ reporter fusion was induced severalfold in the wild type and in the mucA mutant upon exposure to osmotic stress, whereas a lower, noninducible level of expression was observed in the algU mutant. Overexpression of algU did not enhance tolerance towards osmotic stress. AlgU was found to be essential for tolerance of P. fluorescens towards desiccation stress in a sterile vermiculite-sand mixture and in a natural sandy loam soil. The size of the population of the algU mutant declined much more rapidly than the size of the wild-type population at soil water contents below 5%. In contrast to its role in pathogenic pseudomonads, AlgU did not contribute to tolerance of P. fluorescens towards oxidative and heat stress. In conclusion, AlgU is a crucial determinant in the adaptation of P. fluorescens to dry conditions and hyperosmolarity, two major stress factors that limit bacterial survival in the environment.

Improvement of the specificity of cancer detection by autofluorescence imaging in the tracheo-bronchial tree using backscattered violet light.

BACKGROUND: Autofluorescence bronchoscopy (AFB) is a highly sensitive tool for the detection of early bronchial cancers. However, its specificity remains limited due to primarily false positive results induced by hyperplasia, metaplasia and inflammation. We have investigated the potential of blue-violet backscattered light to eliminate false positive results during AFB in a clinical pilot study. METHODS: The diagnostic autofluorescence endoscopy (DAFE) system was equipped with a variable band pass filter in the imaging detection path. The backscattering properties of normal and abnormal bronchial mucosae were assessed by computing the contrast between the two tissue types for blue-violet wavelengths ranging between 410 and 490 nm in 12 patients undergoing routine DAFE examination. In a second study including 6 patients we used a variable long pass (LP) filter to determine the spectral design of the emission filter dedicated to the detection of this blue-violet light with the DAFE system. RESULTS: (Pre-)neoplastic mucosa showed a clear wavelength dependence of the backscattering properties of blue-violet light while the reflectivity of normal, metaplastic and hyperplastic autofluorescence positive mucosa was wavelength independent. CONCLUSIONS: Our results showed that the detection of blue-violet light has the potential to reduce the number of false positive results in AFB. In addition we determined the spectral design of the emission filter dedicated to the detection of this blue-violet light with the DAFE system.

Guayule and Russian dandelion as alternative sources of natural rubber.

Natural rubber, obtained almost exclusively from the Para rubber tree (Hevea brasiliensis), is a unique biopolymer of strategic importance that, in many of its most significant applications, cannot be replaced by synthetic rubber alternatives. Several pressing motives lead to the search for alternative sources of natural rubber. These include increased evidence of allergenic reactions to Hevea rubber, the danger that the fungal pathogen Microcyclus ulei, causative agent of South American Leaf Blight (SALB), might spread to Southeast Asia, which would severely disrupt rubber production, potential shortages of supply due to increasing demand and changes in land use, and a general trend towards the replacement of petroleum-derived chemicals with renewables. Two plant species have received considerable attention as potential alternative sources of natural rubber: the Mexican shrub Guayule (Parthenium argentatum Gray) and the Russian dandelion (Taraxacum koksaghyz). This review will summarize the current production methods and applications of natural rubber (dry rubber and latex), the threats to the production of natural rubber from the rubber tree, and describe the current knowledge of the production of natural rubber from guayule and Russian dandelion.

Parachlamydia acanthamoebae, an emerging agent of pneumonia.

Parachlamydia acanthamoebae is a Chlamydia-like organism that easily grows within Acanthamoeba spp. Thus, it probably uses these widespread free-living amoebae as a replicative niche, a cosmopolite aquatic reservoir and a vector. A potential role of P. acanthamoebae as an agent of lower respiratory tract infection was initially suggested by its isolation within an Acanthamoeba sp. recovered from the water of a humidifier during the investigation of an outbreak of fever. Additional serological and molecular-based investigations further supported its pathogenic role, mainly in bronchiolitis, bronchitis, aspiration pneumonia and community-acquired pneumonia. P. acanthamoebae was shown to survive and replicate within human macrophages, lung fibroblasts and pneumocytes. Moreover, this strict intracellular bacterium also causes severe pneumonia in experimentally infected mice, thus fulfilling the third and fourth Koch criteria for a pathogenic role. Consequently, new tools have been developed for the diagnosis of parachlamydial infections. It will be important to routinely search for this emerging agent of pneumonia, as P. acanthamoebae is apparently resistant to quinolones, which are antibiotics often used for the empirical treatment of atypical pneumonia. Other Chlamydia-related bacteria, including Protochlamydia naegleriophila, Simkania negevensis and Waddlia chondrophila, might also cause lung infections. Moreover, several additional novel chlamydiae, e.g. Criblamydia sequanensis and Rhabdochlamydia crassificans, have been discovered and are now being investigated for their human pathogenicity.

A Multi-Center Phase II Study (SAKK 36/06) of Single Agent Everolimus (RAD001) In Patients with Relapsed or Refractory Mantle Cell Lymphoma

Introduction: Mantle cell lymphoma (MCL) accounts for 6% of all B-cell lymphomas and remains incurable for most patients. Those who relapse after first line therapy or hematopoietic stem cell transplantation have a dismal prognosis with short response duration after salvage therapy. On a molecular level, MCL is characterised by the translocation t[11;14] leading to Cyclin D1 overexpression. Cyclin D1 is downstream of the mammalian target of rapamycin (mTOR) kinase and can be effectively blocked by mTOR inhibitors such as temsirolimus. We set out to define the single agent activity of the orally available mTOR inhibitor everolimus (RAD001) in a prospective, multi-centre trial in patients with relapsed or refractory MCL (NCT00516412). The study was performed in collaboration with the EU-MCL network. Methods: Eligible patients with histologically/cytologically confirmed relapsed (not more than 3 prior lines of systemic treatment) or refractory MCL received everolimus 10 mg orally daily on day 1 - 28 of each cycle (4 weeks) for 6 cycles or until disease progression. The primary endpoint was the best objective response with adverse reactions, time to progression (TTP), time to treatment failure, response duration and molecular response as secondary endpoints. A response rate of ≤ 10% was considered uninteresting and, conversely, promising if ≥ 30%. The required sample size was 35 pts using the Simon's optimal two-stage design with 90% power and 5% significance. Results: A total of 36 patients with 35 evaluable patients from 19 centers were enrolled between August 2007 and January 2010. The median age was 69.4 years (range 40.1 to 84.9 years), with 22 males and 13 females. Thirty patients presented with relapsed and 5 with refractory MCL with a median of two prior therapies. Treatment was generally well tolerated with anemia (11%), thrombocytopenia (11%), neutropenia (8%), diarrhea (3%) and fatigue (3%) being the most frequent complications of CTC grade III or higher. Eighteen patients received 6 or more cycles of everolimus treatment. The objective response rate was 20% (95% CI: 8-37%) with 2 CR, 5 PR, 17 SD, and 11 PD. At a median follow-up of 6 months, TTP was 5.45 months (95% CI: 2.8-8.2 months) for the entire population and 10.6 months for the 18 patients receiving 6 or more cycles of treatment. Conclusion: This study demonstrates that single agent everolimus 10 mg once daily orally is well tolerated. The null hypothesis of inactivity could be rejected indicating a moderate anti-lymphoma activity in relapsed/refractory MCL. Further studies of either everolimus in combination with chemotherapy or as single agent for maintenance treatment are warranted in MCL.

Evaluation cardiologique préopératoire avant chirurgie non cardiaque: du choix cornélien a l'arbre décisionnel [Pre-operative cardiac assessment in non-cardiac surgery: a frequent dilemma simplified by a decision tree].

In patients undergoing non-cardiac surgery, cardiac events are the most common cause of perioperative morbidity and mortality. It is often difficult to choose adequate cardiologic examinations before surgery. This paper, inspired by the guidelines of the European and American societies of cardiology (ESC, AHA, ACC), discusses the place of standard ECG, echocardiography, treadmill or bicycle ergometer and pharmacological stress testing in preoperative evaluations. The role of coronary angiography and prophylactic revascularization will also be discussed. Finally, we provide a decision tree which will be helpful to both general practitioners and specialists.

Wood ants protect their brood with tree resin

Social insects use multiple lines of collective defences to combat pathogens. One example of a behav- ioural group defence is the use of antimicrobial plant compounds to disinfect the nest. Indeed, wood ants collect coniferous tree resin, and the presence of resin in their nest protects them against fungal and bacterial pathogens. Many questions remain on the mechanisms of resin use, including which factors elicit resin collection and placement within nests. Here, we investigated whether the presence of brood induces Formica paralugubris workers to collect more resin, and whether the workers preferentially place resin near the brood. We also tested whether the collection and placement of resin depends on the presence of the fungal entomopathogen Beauveria bassiana. Workers brought more resin to their nest when brood was present, and preferentially placed the resin near the brood. In contrast, workers did not increase resin collection in response to exposure to B. bassiana, nor did they place resin closer to contaminated brood or contaminated areas of the nest. This lack of response may be explained by a limited effect of resin against the germination and growth of B. bassiana in vitro. Overall, our main result is that woods ants actively position resin near the brood, which probably confers prophylactic protection against other detrimental microorganisms.

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil

Terrestrial arthropods from tree canopies in the Pantanal of Mato Grosso, Brazil. This study represents a contribution to the knowledge of the diversity of arthropods associated to the canopy of Vochysia divergens Pohl (Vochysiaceae). Three trees individuals were sampled during two seasonal periods in this region: a) by spraying one tree canopy during high water (February); b) by fogging two tree canopies during low water (September/October). The 15,744 arthropods (183.2±38.9 individuals/m²) obtained from all three trees (86 m²) represented 20 taxonomic orders, 87.1% were Insecta, and 12.9% Arachnida. The dominant groups were Hymenoptera (48.5%; 88.9 individuals/m²), mostly Formicidae (44.5%; 81.4 individuals/m²), followed by Coleoptera (14.0%; 25.5 individuals/m²) and Araneae (10.2%; 19.5 individuals/m²), together representing 62.5% of the total catch. Fourteen (70%) of all orders occurred on three trees. Dermaptera, Isoptera, Neuroptera, Odonata, Plecoptera and Trichoptera were collected from only one tree. Of the total, 2,197 adult Coleoptera collected (25.5±11.3 individuals/m²), 99% were assigned to 32 families and 256 morphospecies. Nitidulidae (17.9% of the total catch; 4.6 individuals/m²), Anobiidae (16.7%; 4.3 individuals/m²), Curculionidae (13.2%; 3.4 individuals/m²) and Meloidae (11.4%; 2.9 individuals/m²) dominated. The communitiy of adult Coleoptera on V. divergens indicated a dominance of herbivores (37.8% of the total catch, 127 spp.) and predators (35.2%, 82 spp.), followed by saprophages (16.2%, 32 spp.) and fungivores (10.8%, 15 spp.). The influence of the flood pulse on the community of arboreal arthropods in V. divergens is indicated by the seasonal variation in evaluated groups, causing changes in their structure and composition.