Effect of electromagnetic nanopulses on C. elegans fertility

Electromagnetic nanopulse exposure results in decreased fertility of C. elegans, a well studied, multicellar organism. Experiments indicate that this effect is unlikely to be due to heating. Instead, nanopulses interfere with fertilization or development by an as yet undetermined mechanism. Study of nanopulse exposure of C. elegans could help to understand more generally how living organisms interact with electromagnetic fields.     

Postnatal Expression of GAD67

N-methyl-d-aspartate receptor blockade promotes apoptosis at postnatal day 7 (P7) and is linked to loss of glutamic acid decarboxylase 67 (GAD67) expression in older animals. To more fully appreciate this relationship we must first understand how GAD67 is regulated postnatally. Thus, the brains of P7, P14 and P21 rats were examined for expression of GAD67 protein and we found that levels of this GABAergic marker increased steadily with age, such that by P21 there was as much as a 6-fold increase compared to P7 animals and a 1.5- to 2-fold increase compared to P14 animals, depending on the region sampled. At P7, GAD67 was almost exclusively detected in puncta, with very few cell bodies displaying this marker. In contrast, at P14 and especially P21, both puncta and cell bodies were robustly labeled. Our data indicate that adult-like expression of GAD67 emerges quite late in the postnatal period.     

Gene disruption by structural mutations drives selection in US rice breeding over the last century

The genetic basis of general plant vigor is of major interest to food producers, yet the trait is recalcitrant to genetic mapping because of the number of loci involved, their small effects, and linkage. Observations of heterosis in many crops suggests that recessive, malfunctioning versions of genes are a major cause of poor performance, yet we have little information on the mutational spectrum underlying these disruptions. To address this question, we generated a long-read assembly of a tropical japonica rice (Oryza sativa) variety, Carolina Gold, which allowed us to identify structural mutations (>50 bp) and orient them with respect to their ancestral state using the outgroup, Oryza glaberrima. Supporting prior work, we find substantial genome expansion in the sativa branch. While transposable elements (TEs) account for the largest share of size variation, the majority of events are not directly TE-mediated. Tandem duplications are the most common source of insertions and are highly enriched among 50-200bp mutations. To explore the relative impact of various mutational classes on crop fitness, we then track these structural events over the last century of US rice improvement using 101 resequenced varieties. Within this material, a pattern of temporary hybridization between medium and long-grain varieties was followed by recent divergence. During this long-term selection, structural mutations that impact gene exons have been removed at a greater rate than intronic indels and single-nucleotide mutations. These results support the use of ab initio estimates of mutational burden, based on structural data, as an orthogonal predictor in genomic selection.     

Detection of oxidative stress induced by low- and high-linear energy transfer radiation in cultured human epithelial cells

A standardized dichlorofluorescin (DCF) fluorometric assay capable of measuring radiation-induced oxidative stress was used to determine the effectiveness of protons and high-mass, high-atomic number (Z) and high-energy (HZE) particles to produce oxidative stress in vitro. Protons were found to be about equally as effective as X rays in the generation of oxidative stress in cultured cells. However, 56Fe-ion beams with energies of 1 GeV/nucleon and 5 GeV/nucleon were less effective than X rays or gamma rays in inducing dichlorofluorescin (DCFH) oxidation. The relatively lower slope values for the dose responses of HZE-particle radiation-induced DCFH oxidation indicate that the sensitivity of the DCF fluorometric assay is probably dependent on the linear energy transfer (LET) of the radiation beam.     

Chemical protection of Calvia quatuordecimguttata eggs against intraguild predation by the invasive ladybird Harmonia axyridis

Intraspecific and interspecific predation of eggs is a well documented phenomenon amongst aphidophagous coccinellids. The invasive species Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is known to be a top intraguild predator and reported to attack the eggs of many coccinellid species both in a laboratory setting and in the wild. A previous laboratory study highlighted that while many species’ eggs were highly palatable to H. axyridis, the eggs of Calvia quatuordecimguttata (Linnaeus) (Coleoptera: Coccinellidae) appeared to be extremely well protected from attack. Here we present the results of behavioural experiments testing the hypothesis that substances on the egg surface are responsible for this protection, and report preliminary results of GC-MS analysis of these compounds. When the coatings of C. quatuordecimguttata eggs were removed using hexane, they became significantly more susceptible to predation by neonate H. axyridis larvae. However, their overall palatability was not affected, in that complete consumption was never or rarely observed. This suggests that the surface compounds are a true indicator of unpalatability in this species. The effect of hexane-washing on already palatable conspecific eggs was also analysed but had no significant effect on the susceptibility of eggs to cannibalism. We conclude that the eggs of at least one European species are effectively protected by surface deterrents from intraguild predation by H. axyridis. This effect might be due to both the diversity and abundance of hydrocarbons present within the egg coating, the presence of alkenes and/or the presence of patches of a red substance on the eggs’ surface, which is thought to belong to the acid group. In conjunction with data on the susceptibility of other immature stages of C. quatuordecimguttata, this finding may indicate a decreased risk of the species falling victim to invasive H. axyridis, despite their coincident habitat ranges.     

Intraguild predation involving Harmonia axyridis: a review of current knowledge and future perspectives

As an effective generalist predator of aphids and other hemipteran pests H. axyridis has been a successful biological control agent. However, the very functional traits that have contributed to its success in this regard also implicate it as an intraguild predator that poses a significant risk not only to the diversity of other natural enemies of Hemiptera (and their associated ecosystem services), but to biodiversity more widely. In this paper we will specifically review the existing data on intraguild predation involving H. axyridis, and consider the strength and symmetry of such interactions both within its native guild and within exotic guilds where it has established as an invasive alien. We will use these studies to interpret the observed population declines in predator diversity in the field, predict species at risk in regions not yet invaded and consider implications for resulting ecosystem services. We will also indicate gaps in our knowledge that require further study in order to identify opportunities for mitigation.     

Keratinocyte and hepatocyte growth factors in the lung: roles in lung development, inflammation, and repair

A growing body of evidence indicates that the epithelial-specific growth factors keratinocyte growth factor (KGF), fibroblast growth factor (FGF)-10, and hepatocyte growth factor (HGF) play important roles in lung development, lung inflammation, and repair. The therapeutic potential of these growth factors in lung disease has yet to be fully explored. KGF has been best studied and has impressive protective effects against a wide variety of injurious stimuli when given as a pretreatment in animal models. Whether this protective effect could translate to a treatment effect in humans with acute lung injury needs to be investigated. FGF-10 and HGF may also have therapeutic potential, but more extensive studies in animal models are needed. Because HGF lacks true epithelial specificity, it may have less potential than KGF and FGF-10 as a targeted therapy to facilitate lung epithelial repair. Regardless of their therapeutic potential, studies of the unique roles played by these growth factors in the pathogenesis and the resolution of acute lung injury and other lung diseases will continue to enhance our understanding of the complex pathophysiology of inflammation and repair in the lung.     

Phospholipid dependence of calcium ion effects on electrophoretic mobilities of liposomes

Electrophoretic light scattering (ELS) and depolarization of fluorescence have been used to determine the effect of membrane fluidity on the binding of Ca2+ to liposomes. ELS was used to measure the electrophoretic mobilities of the liposomes. Fluorescence depolarization was used to determine membrane fluidity. Zero to 30 mol% phosphatidylserine (PS) was incorporated into liposomes containing, as bulk phospholipids, one of the following: dimyristoyl-phosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC), egg phosphatidylcholine (PC), or hydrogenated egg phosphatidylcholine (H egg PC). The binding of Ca2+ to the liposomes appears to be influenced by membrane fluidity. Liposomes containing bulk phospholipids whose phase transition temperature is higher than the experimental temperature exhibit enhanced binding of CA2+.     

Expression of Lex antigen in Schistosoma japonicum and S.haematobium and immune responses to Lex in infected animals: lack of Lex expression in other trematodes and nematodes

Adults of the human parasitic trematode Schistosoma mansoni, which causes hepatosplenic/intestinal complications in humans, synthesize glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1-- >3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now report on our analyses of Lexand sLexexpression in S.haematobium and S.japonicum, which are two other major species of human schistosomes that cause disease, and the possible autoimmunity to these antigens in infected individuals. Antigen expression was evaluated by both ELISA and Western blot analyses of detergent extracts of parasites using monoclonal antibodies. Several high molecular weight glycoproteins in both S. haematobium and S. japonicum contain the Lexantigen, but no sialyl Lexantigen was detected. In addition, sera from humans and rodents infected with S.haematobium and S.japonicum contain antibodies reactive with Lex. These results led us to investigate whether Lexantigens are expressed in other helminths, including the parasitic trematode Fasciola hepatica , the parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant nematode Haemonchus contortus , and the free-living nematode Caenorhabditis elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths. Furthermore, none of the helminths, including schistosomes, express Lea, Leb, Ley, or the H- type 1 antigen. However, several glycoproteins from all helminths analyzed are bound by Lotus tetragonolobus agglutinin , which binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be unique among helminths in expressing the Lexantigen, whereas many different helminths may express alpha1,3-fucosylated glycans and the LDN motif.