A benign approach to the preparation of freshwater bryozoan statoblasts for scanning electron microscopy (SEM) imaging

Abstract

Several different species of freshwater Bryozoa, belonging to the genera Plumatella, Rumarcanella and Fredericella, were detected within the Northern Mallee Pipeline (NMP) system in Victoria, Australia, that required definitive identification. These organisms produce asexual buds called statoblasts, with valves composed of sclerotised chitin that bear minute micro-ornamentations of considerable taxonomical significance. Imaging and analysis of these distinctive micro-ornamentations using scanning electron microscopy (SEM) is often employed for species identification. Meticulous preparation of statoblast samples is therefore required that necessitates the removal of adhering debris, dehydration and drying—whilst mitigating specimen damage and distortion. This technical note describes an approach whereby each of these three steps have been individually designed to be as benign as possible, using mild detergent/sonication to remove debris, a gradual and gentle dehydration procedure using ethanol, and critical point drying. For the overall process, these methods are chosen to optimise control and to minimise the use of harsh and hazardous chemicals.     

Genetic bases for heterogeneity of a population of omnivorous Archips podana Scop. leaf roller moths (Lepidoptera: Tortricidae) by morphological and behavioral traits

Inheritance of morphological characters related to male and female genitalia was examined in Archips podana Scop. The position and number of aedeagus prongs had a monogenic diallelic mode of inheritance. In contrast to homozygous for P1 (prong A) and heterozygous (prong A + B) males, males homozygous for P2 (prong B) were characterized by much more active courtship. The gene correlates with a set of characters controlling individual ecology, exploring behavior of females, and feeding on different cultures. Morphological adult type 0 is an extremely weak form of phenotype B. Exploring activity of adults having phenotype B is the highest at the ratio of cis-tetradecenol to the other components of the female sex pheromone that leads to a somewhat lower activity of males of other phenotypes. In females, no regularities in inheritance of phenotypic characters were revealed. A hypothesis on a mechanism for maintenance of population stability for the given phenotypes is advanced and a possible mechanism for microevolution of a polymorphic species is proposed.     

The use of adjunctive GPIIb/IIIa inhibitors in patients with unstable angina/non-Q-wave MI undergoing percutaneous coronary intervention

Glycoprotein IIb/IIIa receptor inhibitors represent a relatively new therapeutic approach in the field of antiplatelet therapy. Following the development of abciximab a number of small molecule GPIIb/IIIa inhibitors have been introduced such as tirofiban and eptifibatide. In this fast-moving field the interventional cardiologist needs a framework to guide decision-making for the individual patient. This review covers the efficacy and safety data from the clinical trials of GPIIb/IIIa inhibitors in the context of patients undergoing percutaneous coronary intervention for unstable angina/non-Q-wave myocardial infarction. There is an increasing body of evidence to support the efficacy of GPIIb/IIIa inhibitors in reducing the risk of adverse ischemic events in high and low risk patients undergoing percutaneous coronary intervention. A number of unresolved efficacy and safety issues remain, including the duration of treatment before and after intervention; whether a reduction in the heparin dose would further decrease the risk of hemorrhage without affecting the periprocedural thrombotic rate in patients undergoing PTCA with adjunctive GPIIb/IIIa inhibitors; and the cost-effectiveness of this therapy. When a thorough analysis of cost-effectiveness has been made, it will be easier to advocate the widespread use of these agents in all patients undergoing coronary intervention.     

A high-throughput cloning system for reverse genetics in <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis>

Background  

The three trypanosomatids pathogenic to men, Trypanosoma cruzi, Trypanosoma brucei and Leishmania major, are etiological agents of Chagas disease, African sleeping sickness and cutaneous leishmaniasis, respectively. The complete sequencing of these trypanosomatid genomes represented a breakthrough in the understanding of these organisms. Genome sequencing is a step towards solving the parasite biology puzzle, as there are a high percentage of genes encoding proteins without functional annotation. Also, technical limitations in protein expression in heterologous systems reinforce the evident need for the development of a high-throughput reverse genetics platform. Ideally, such platform would lead to efficient cloning and compatibility with various approaches. Thus, we aimed to construct a highly efficient cloning platform compatible with plasmid vectors that are suitable for various approaches.     

Immunoprophylaxis of respiratory syncytial virus: global experience

In sarcoidosis, host genetic factors are discussed as contributing to disease susceptibility and course. Since tumor necrosis factor (TNF)-α is a central mediator of granuloma formation and since elevated TNF-α levels are found during active phases of sarcoidosis, genetic polymorphisms correlating with influences on TNF-α levels are of special interest. The complete sequencing of the MHC region and the increase in the number of identified gene polymorphisms in this locus associated with TNF-α production offer the opportunity of detecting new genes associated with sarcoidosis and perhaps of defining disease-associated haplotypes that bear the potential of serving as predictive markers for this disease.     

Evolution of postgonites in frit flies (Diptera,Chloropidae, <Emphasis Type="Italic">Meromyza</Emphasis>)

Evolutionary trends of the morphometric characteristics of postgonites (structures important for copulation) and variability of the mtDNA COI gene region were analyzed for 27 species of the genus Meromyza Mg. The total area, the area and height of the protuberance, and the length ratio of the main part and the protuberance were analyzed for the anterior process of the postgonite. The height and way of attachment were analyzed for the posterior process of the postgonite. Based on the mtDNA COI locus, eight clusters were distinguished in Network; they formed three groups differing in the area of the anterior process and the way of attachment of the posterior process. The size characteristics of the male sexual appendages of the ancestral forms within the genus Meromyza show an evolutionary trend toward an increase in the postgonite area, while within the clusters there is a trend toward a decrease in this area relative to the species most resembling the hypothetical ancestor. The ancestral forms were characterized by a small area of the postgonite and a short and narrow protuberance of its anterior process. An increase in this area may have led to reduction of the statistical significance of differences in the protuberance and to the appearance of a flap on the lateral part of the postgonite. The functional significance of the postgonite elements and the flap is discussed. Based on the studied morphometric characteristics, the species M. maculata and M. cognata can be placed in the known clusters, even though their COI sequences have not been determined.     

Flexibility in crosstalk between H2B ubiquitination and H3 methylation in vivo

Histone H2B ubiquitination is a dynamic modification that promotes methylation of histone H3K79 and H3K4. This crosstalk is important for the DNA damage response and has been implicated in cancer. Here, we show that in engineered yeast strains, ubiquitins tethered to every nucleosome promote H3K79 and H3K4 methylation from a proximal as well as a more distal site, but only if in a correct orientation. This plasticity indicates that the exact location of the attachment site, the native ubiquitin-lysine linkage and ubiquitination cycles are not critical for trans-histone crosstalk in vivo. The flexibility in crosstalk also indicates that other ubiquitination events may promote H3 methylation.