An extract of Commiphora erythraea: a repellent and toxicant against ticks

A hexane extract of the gum of an African plant, Commiphora erythraea Engler (Burseraceae), has larvicidal and repellent activity against the lone star tick, Amblyomma americanum (L.) and the American dog tick, Dermacentor variabilis (Say). Adult deer ticks, Ixodes dammini Spielman, Clifford, Piesman and Corwin, were also repelled by the extract. Concentrations of 0.02 mg/cm² of the extract impregnated onto filter paper killed 96.15 (±3.56)% of A. americanum larvae exposed to it for 24h. A concentration of 0.16 mg/cm² was needed to kill 80.3% of D. variabilis larvae. The extract was less effective as a larvicide against A. americanum and D. variabilis than permethrin. Less than 15.5% of A. americanum larvae and adults and D. variabilis and I. dammini adults entered and remained for 2 or 3 min on areas of cloth strips treated with the extract at the rate of 0.2 mg/cm². However, 73.3 to 83.3% of the ticks tested entered and remained in areas treated with hexane. Permethrin was about 1 or 2 orders of magnitude more effective against A. americanum larvae as a repellent than the extract.

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Résumé Un extrait à l'hexane de la gomme de la plante africaine, C. erythraea Engler (Burseraceae) a des effets larvicides et répulsifs contre les tiques, Amblyomma americanum L. et Dermacentor variabilis Say; les adultes de Ixodes dammini Spielman, Clifford, Piesman & Corwin, ont été aussi éloignés par l'extrait. Une concentration de 0,02 mg/cm² de l'extrait imprégnant du papier filtre a tué 96,15% (±3,56) larves de A. americanum exposées pendant 24 h. Une concentration de 0,16 mg/cm² a été nécessaire pour tuer 80,3% des larves de D. variabilis. L'extrait a été moins efficace que la perméthrine comme larvicide contre A. americanum et D. variabilis. Moins de 15,5% des larves et des adultes de A. americanum et des adultes de D. variabilis et de I. dammini pénétrèrent et séjournèrent 2 à 3 minutes dans des morceaux de tissu traités avec l'extrait à raison de 0,2 mg/cm², contre 73,3 et 83,3% qui pénétrèrent et restèrent lors de traitement avec de l'hexane. Contre A. americanum, la perméthrine est un répulsif d'un ordre de grandeur une à deux fois supérieur à l'extrait de C. erythraea.

     

6-d-glucopyranosyl fatty acid esters from Brassica napus pollen

6-d-Glucopyranosyl esters of palmitic, oleic, linoleic and linolenic acids were identified in Brassica napus (rape) pollen. These esters are inactive as plant growth promoters in the bean second-internode bioassay.     

Immunohistochemistry in the evaluation of neovascularization in tumor xenografts

Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry is widely used in experimental studies for quantifying tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected by variations in the methodology used to measure vascularization including antibody selection, antigen retrieval (AR) pretreatment, and evaluation techniques. To examine this further, we investigated the microvessel density (MVD) and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg immunohistochemical staining. Different AR methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, anti-CD31 highlighted small vessels better than F VIII RAg. Furthermore, the MVD of CD31 was significantly greater than that of F VIII RAg decorated vessels (p<0.001). The choice of antibody and AR method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.     

Dietary input of microbes and host genetic variation shape among-population differences in stickleback gut microbiota

To explain differences in gut microbial communities we must determine how processes regulating microbial community assembly (colonization, persistence) differ among hosts and affect microbiota composition. We surveyed the gut microbiota of threespine stickleback (Gasterosteus aculeatus) from 10 geographically clustered populations and sequenced environmental samples to track potential colonizing microbes and quantify the effects of host environment and genotype. Gut microbiota composition and diversity varied among populations. These among-population differences were associated with multiple covarying ecological variables: habitat type (lake, stream, estuary), lake geomorphology and food- (but not water-) associated microbiota. Fish genotype also covaried with gut microbiota composition; more genetically divergent populations exhibited more divergent gut microbiota. Our results suggest that population level differences in stickleback gut microbiota may depend more on internal sorting processes (host genotype) than on colonization processes (transient environmental effects).     

Caspase-mediated cleavage of the exosome subunit PM/Scl-75 during apoptosis

Recent studies have implicated the dying cell as a potential reservoir of modified autoantigens that might initiate and drive systemic autoimmunity in susceptible hosts. A number of subunits of the exosome, a complex of 3'→5' exoribonucleases that functions in a variety of cellular processes, are recognized by the so-called anti-PM/Scl autoantibodies, found predominantly in patients suffering from an overlap syndrome of myositis and scleroderma. Here we show that one of these subunits, PM/Scl-75, is cleaved during apoptosis. PM/Scl-75 cleavage is inhibited by several different caspase inhibitors. The analysis of PM/Scl-75 cleavage by recombinant caspase proteins shows that PM/Scl-75 is efficiently cleaved by caspase-1, to a smaller extent by caspase-8, and relatively inefficiently by caspase-3 and caspase-7. Cleavage of the PM/Scl-75 protein occurs in the C-terminal part of the protein at Asp369 (IILD³⁶⁹↓G), and at least a fraction of the resulting N-terminal fragments of PM/Scl-75 remains associated with the exosome. Finally, the implications of PM/Scl-75 cleavage for exosome function and the generation of anti-PM/Scl-75 autoantibodies are discussed.     

Issues in using whole slide imaging for diagnostic pathology: “routine” stains,immunohistochemistry and predictive markers

The traditional microscope, together with the “routine” hematoxylin and eosin (H & E) stain, remains the “gold standard” for diagnosis of cancer and other diseases; remarkably, it and the majority of associated biological stains are more than 150 years old. Immunohistochemistry has added to the repertoire of “stains” available. Because of the need for specific identification and even measurement of “biomarkers,” immunohistochemistry has increased the demand for consistency of performance and interpretation of staining results. Rapid advances in the capabilities of digital imaging hardware and software now offer a realistic route to improved reproducibility, accuracy and quantification by utilizing whole slide digital images for diagnosis, education and research. There also are potential efficiencies in work flow and the promise of powerful new analytical methods; however, there also are challenges with respect to validation of the quality and fidelity of digital images, including the standard H & E stain, so that diagnostic performance by pathologists is not compromised when they rely on whole slide images instead of traditional stained tissues on glass slides.     

Gene structure,transcripts and calciotropic effects of the PTH family of peptides in <Emphasis Type="Italic">Xenopus</Emphasis> and chicken

Background  

Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) belong to a family of endocrine factors that share a highly conserved N-terminal region (amino acids 1-34) and play key roles in calcium homeostasis, bone formation and skeletal development. Recently, PTH-like peptide (PTH-L) was identified in teleost fish raising questions about the evolution of these proteins. Although PTH and PTHrP have been intensively studied in mammals their function in other vertebrates is poorly documented. Amphibians and birds occupy unique phylogenetic positions, the former at the transition of aquatic to terrestrial life and the latter at the transition to homeothermy. Moreover, both organisms have characteristics indicative of a complex system in calcium regulation. This study investigated PTH family evolution in vertebrates with special emphasis on Xenopus and chicken.     

Morphological and molecular characterization of populations of plains bristlegrass (<i>Setaria macrostachya</i> Kunth) in Chihuahua,México

Plains bristlegrass (Setaria macrostachya Kunth) is a native grass with forage value. However, due to the lack of grazing management practices, populations and thus genetic diversity, have been reduced. Morphological and genetic variability were analyzed on 44 populations of plains bristlegrass in the State of Chihuahua. Plants were transplanted in a common area under natural conditions. Two years later, morphological characterization was evaluated measuring nine variables, and genetic variability using AFLP molecular markers. The principal components analysis (PC) showed that the three first principal components explained 73.74% of the variation. The variables with the greatest contribution to the variance in PC1 were plant height and inflorescence length; in CP2, tiller number and leaf width; and in PC3, tiller thickness. Application of four pairs of primers, presented 186 total bands, from which 87.10% showed polymorphism and 12.90% monomorphism. The combination of EcoRI-AGG MseI-CAG primers detected the highest percentage (93%) of polymorphism with 40 polymorphic bands. The cluster analysis and Dice coefficient indicated that populations clump into two groups. The wide genetic variability and morphological characteristics detected among populations represent the basis for the selection of populations that could be used with different purposes in the rehabilitation of ecosystems. In addition, this study will allow establishment of in situ conservation strategies.     

Identification of DNA sequence variation in Campylobacter jejuni strains associated with the Guillain-Barré syndrome by high-throughput AFLP analysis

Background  

Campylobacter jejuni is the predominant cause of antecedent infection in post-infectious neuropathies such as the Guillain-Barré (GBS) and Miller Fisher syndromes (MFS). GBS and MFS are probably induced by molecular mimicry between human gangliosides and bacterial lipo-oligosaccharides (LOS). This study describes a new C. jejuni-specific high-throughput AFLP (htAFLP) approach for detection and identification of DNA polymorphism, in general, and of putative GBS/MFS-markers, in particular.