RIBOSOMAL SUBUNITS FROM NEONATAL MOUSE BRAIN HIGHLY ACTIVE IN POLYPHENYLALANINE SYNTHESIS

Abstract— A highly active subcellular protein synthesising system is described, in which uncomplexed ribosomes isolated from 5 to 7 day old mouse brain can be reprogrammed with polyuridylic acid. Either purified free polyribosomes or microsomes were used as the starting material for the preparation of uncomplexed ribosomes by treatment with 0.5 m -KCl and puromycin. After reduction of the salt concentration 80S ribosomes were isolated by washing through sucrose. When, subsequently, zonal centrifugation in equivolumetric sucrose gradients containing 0.5 m -KCI was performed, purified ribosomal subunits were obtained. Cross-contamination of subunits was less than 5%. Re-associated ribosomes and recombined isolated ribosomal subunits both showed high activities in vitro. Incorporation levels of 50–60 phenylalanine residues per ribosome could be reached, at a rate of 0.5–2.0 residues/min/ribosome, depending on the activity of the high speed supernatant enzymes added. It was shown by paper chromatography of the cell-free product that only oligophenylalanine formation takes place. It was estimated that 6&70% of the ribosomes present in vitro were actively participating in the protein synthesis process.     

One fig to bind them all: host conservatism in a fig wasp community unraveled by cospeciation analyses among pollinating and nonpollinating fig wasps

The study of chalcid wasps that live within syconia of fig trees (Moraceae, Ficus ), provides a unique opportunity to investigate the evolution of specialized communities of insects. By conducting cospeciation analyses between figs of section Galoglychia and some of their associated fig wasps, we show that, although host switches and duplication have evidently played a role in the construction of the current associations, the global picture is one of significant cospeciation throughout the evolution of these communities. Contrary to common belief, nonpollinating wasps are at least as constrained as pollinators by their host association in their diversification in this section. By adapting a randomization test in a supertree context, we further confirm that wasp phylogenies are significantly congruent with each other, and build a "wasp community" supertree that retrieves Galoglychia taxonomic subdivisions. Altogether, these results probably reflect wasp host specialization but also, to some extent, they might indicate that niche saturation within the fig prevents recurrent intrahost speciation and host switching. Finally, a comparison of ITS2 sequence divergence of cospeciating pairs of wasps suggests that the diversification of some pollinating and nonpollinating wasps of Galoglychia figs has been synchronous but that pollinating wasps exhibit a higher rate of molecular evolution.     

Defining the cost of the Egyptian lymphatic filariasis elimination programme

BACKGROUND: Ultrasonography (USG) is known to be a suitable tool for diagnosis in lymphatic filariasis as the adult filarial nematode Wuchereria bancrofti in scrotal lymphatic vessels of infected men can be detected by the characteristic pattern of movement, the Filaria Dance Sign. In onchocerciasis, moving adult worms have not yet been demonstrated by USG. In addition the verification of drug effects on living adult Onchocerca volvulus filariae in trials is hampered by the lack of tools for longitudinal observation of alterations induced by potentially macrofilaricidal drugs in vivo. The present study was carried out to determine the frequency of detection of moving adult filariae of O. volvulus by USG. METHODS: In an endemic region for onchocerciasis in Ghana, 61 patients infected with onchocerciasis were recruited by palpation and onchocercomas examined by USG using an ultrasound system equipped with a 7.5 - 10 MHz linear transducer. Onchocercomas were recorded on videotape and evaluated with regard to location, number and size, as well as to movements of adult filariae. RESULTS: In the 61 patients 303 onchocercomas were found by palpation and 401 onchocercomas were detected by USG. In 18 out of 61 patients (29.5%), altogether 22 nodules with moving adult O. volvulus filariae were detected and are presented in animated ultrasound images as mp-4 videos. CONCLUSION: Ultrasonographical examinations of onchocercomas where living adult filariae can be displayed may serve as a new tool for the longitudinal observation in vivo of patients with onchocerciasis undergoing treatment and as an adjunct to histological evaluation.     

Spermicide by females: what should males do?

The female reproductive tract can be particularly aggressive towards ejaculates, often leading to the death of large numbers of sperm. It has been suggested that males can respond to these actions by investing more in sperm and donating larger ejaculates. Such counteractions may lead to arms races, which can have significant implications for the mating system. In a series of simple models we first show that arms races are not necessarily supported: in fact, sperm killing may even favour no change or reductions in sperm allocation. Second, we identify a simple mechanistic rule for sperm killing that determines whether an arms race or sperm reduction will be favoured. Which of these responses is favoured by selection depends on whether a certain number, or proportion, of sperm are killed. When a specific number is killed, larger investment in sperm is favoured and when a specific proportion is killed, no change or lower investment in sperm is favoured. Both of these mechanisms are biologically plausible.     

Irisin immunohistochemistry in gastrointestinal system cancers

Cancer is the leading cause of morbidity and mortality worldwide. Some studies have shown that high heat kills cancer cells. Irisin is a protein involved in heat production by converting white into brown adipose tissue, but there is no information about how its expression changes in cancerous tissues. We used irisin antibody immunohistochemistry to investigate changes in irisin expression in gastrointestinal cancers compared to normal tissues. Irisin was found in human brain neuroglial cells, esophageal epithelial cells, esophageal epidermoid carcinoma, esophageal adenocarcinoma and neuroendocrine esophageal carcinoma, gastric glands, gastric adenosquamous carcinoma, gastric neuroendocrine carcinoma, gastric signet ring cell carcinoma, neutrophils in vascular tissues, intestinal glands of colon, colon adenocarcinoma, mucinous colon adenocarcinoma, hepatocytes, hepatocellular carcinoma, islets of Langerhans, exocrine pancreas, acinar cells and interlobular and interlobular ducts of normal pancreas, pancreatic ductal adenocarcinoma, and intra- and interlobular ducts of cancerous pancreatic tissue. Histoscores (area × intensity) indicated that irisin was increased significantly in gastrointestinal cancer tissues, except liver cancers. Our findings suggest that the relation of irisin to cancer warrants further investigation.     

Patterns of diversification of Afrotropical Otiteselline fig wasps: phylogenetic study reveals a double radiation across host figs and conservatism of host association

We studied the phylogenetic relationships of Otiteselline fig waSPS associated with Ficus in the Afrotropical region using rDNA sequences. African fig species usually host two species of Otiteselline fig waSPS. Phylogenetic analyses reveal that this pattern of association results from the radiation of two clades of waSPS superimposed on the fig system. Within each clade, wasp species generally cluster according to their host classification. The phylogenies of the two clades are also generally more congruent than expected by chance. Together these results suggest that Otiteselline wasp speciation is largely constrained by the diversification of their hosts. Finally, we show a difference in ovipositor length between the two Otiteselline species coexisting in the same Ficus species, which probably corresponds to ecological differences. The diversification of ecological niches within the fig is probably, with cospeciation, one of the key factors explaining the diversification and maintenance of species of parasites of the fig/pollinator system.     

Evidence for an early evolutionary emergence of γ-type carbonic anhydrases as components of mitochondrial respiratory complex I

Background  

The complexity of mitochondrial complex I (CI; NADH:ubiquinone oxidoreductase) has increased considerably relative to the homologous complex in bacteria. Comparative analyses of CI composition in animals, fungi and land plants/green algae suggest that novel components of mitochondrial CI include a set of 18 proteins common to all eukaryotes and a variable number of lineage-specific subunits. In plants and green algae, several purportedly plant-specific proteins homologous to γ-type carbonic anhydrases (γCA) have been identified as components of CI. However, relatively little is known about CI composition in the unicellular protists, the characterizations of which are essential to our understanding of CI evolution.