Monitoring of early events of experimental woodchuck hepatitis infection: Studies of peripheral blood mononuclear cells by cytofluorometry and PCR

Abstract The peripheral blood mononuclear cells (PBMC) of woodchucks experimentally infected by woodchuck hepatitis virus (WHV) were examined simultaneously for the presence of membrane associated WHV antigens by cytofluorometry, and for WHV DNA and RNA sequences by the polymerase chain reaction (PCR). Four woodchucks were inoculated: two with a well-defined infectious inoculum and two with an inoculum obtained from an animal at the late incubation phase, which was positive for WHV DNA by PCR but still devoid of WHV markers. Infection was demonstrated in all four inoculated woodchucks by the appearance at different times of WHV DNA and WHV antigens in both leucocytes and serum. WHV DNA was first detected by PCR either in the serum (two cases) or in leucocytes (two cases). The mean percentage of cells positive for membrane associated WHsAg or WHcAg detected by cytofluorometry were 37%±25 and 17%±15 respectively. After 8 weeks, all inoculated animals were WHsAg positive in serum. These data suggest that PBMC are involved in the early events of hepadnavirus infection. They also show that sera which are positive by PCR for WHV DNA may transmit viral infection even while still seronegative for WHV markers and for WHV DNA by dot blot.     

Identification and characterization of 10 polymorphic microsatellite loci in the German cockroach,Blattella germanica

Primer sequences and initial characterization are presented for 10 microsatellite loci isolated from the German cockroach, Blattella germanica. In a sample of 30 individuals from a single population sample, all loci were polymorphic with two to 12 alleles segregating per locus and levels of observed heterozygosity ranging from 0.27 to 0.92. One locus showed a deficit of heterozygotes. Experimental conditions are described for polymerase chain reaction multiplexing, which enables the genotyping of eight loci in three electrophoretic runs consisting of one set of three and two sets of two markers. Seven primer sets cross‐amplify in the related Blattella asahinai.     

Impact of exogenous lysolipids on sensitive and multidrug resistant K562 cells: 1H NMR studies

The ability of lysolipids to enter into a membrane bi-layer and disturb the membrane structure was used to study the behavior of K562 erythroleukemic cells, K562 wild type (K562wt) as well as the multidrug resistant cells K562adr. Both types of cells, when analyzed by proton NMR spectroscopy exhibit the high resolution signals assigned to so-called "mobile lipid" signals, which, in most cases, are located outside the lipid bi-layer as lipid droplets. In order to perform these studies, the K562wt and K562adr cells were treated for 48h with lysophosphatidylcholine oleoyl (LPC18), lysophosphatidylcholine palmitoyl (LPC16) and L-alpha-lysophosphatidyslerine (LPS). After evaluating toxicity of lysolipids, proton NMR of whole treated cells was used to analyze the mobile lipid content. Nile red staining and fluorescence microscopy were used to detect the presence of intracellular lipid droplets. Membrane lipid asymmetry perturbation was estimated by annexin V staining with use of flow cytometry. Using fluorescence spectroscopy the functioning of P-glycoprotein (P-gp) responsible for multidrug resistance was also evaluated after the treatment with lysolipids. Lysolipids were found to be more toxic for K562wt than for K562adr cells. LPS and LPC16 produced an increased of a mobile lipid NMR signal and amount of lipid droplets in K562wt cells only. LPC18, with the lowest toxicity, has shown more intense effects on NMR spectra with a large increase of lipid NMR signal without changes in lipid droplet staining. The functioning of the P-gp pump and membrane asymmetry were not modified by any of the lysolipids used.     

Reshaping of sandstone surfaces by cryptoendolithic cyanobacteria: bioalkalization causes chemical weathering in arid landscapes

We report a novel weathering mechanism in South African sandstone formations, where cryptoendolithic cyanobacteria induce weathering by substrate alkalization during photosynthesis. As a result, the upper rock part is loosened and then eroded away by physical forces such as wind, water, trampling. This special type of ‘exfoliation’ is widely distributed and affects the geomorphology of whole sandstone mountain ranges and outcrops across several biomes. We show, that this weathering type is initiated by bioalkalization because of the photosynthesis of cryptoendolithic (i.e. those organisms living in small tight open spaces between the sand grains) cyanobacteria causing pH values high enough to enhance silica solution in the cryptoendolithic zone. As modern cyanobacteria are the initial photoautotrophic colonizers of bare rocks in arid and semiarid landscapes, it is possible that they may also have played a significant role in shaping sandstone landscapes in the geological past.     

Linear and threshold-dependent expression of secondary sexual traits in the same individual: insights from a horned beetle (Coleoptera: Scarabaeidae)

Elaborate horns or horn‐like structures in male scarab beetles commonly scale with body size either (a) in a linear fashion with horn size increasing relatively faster than body size or (b) in a threshold‐dependent, sigmoid fashion; that is, males smaller than a certain critical body size develop no or only rudimentary horns, whereas males larger than the threshold size express fully developed horns. The development of linear vs. sigmoid scaling relationships is thought to require fundamentally different regulatory mechanisms. Here we show that such disparate regulatory mechanisms may co‐occur in the same individual. Large males of the south‐east Asian Onthophagus (Proagoderus) watanabei (Ochi & Kon) (Scarabaeidae, Onthophagini) develop a pair of long, curved head horns as well as a single thoracic horn. We show that unlike paired head horns in a large number of Onthophagus species, in O. watanabei the relationship between head horns and body size is best explained by a linear model. Large males develop disproportionately longer horns than small males, but the difference in relative horn sizes across the range of body sizes is small compared to other Onthophagus species. However, the scaling relationship between the thoracic horn and body size is best explained by a strongly sigmoid model. Only males above a certain body size threshold express a thoracic horn and males smaller than this threshold express no horn at all. We found a significant positive correlation between head and thoracic horn length residuals, contrary to what would be expected if a resource allocation tradeoff during larval development would influence the length of both horn types. Our results suggest that the scaling relationship between body size and horn length, and the developmental regulation underlying these scaling relationships, may be quite different for different horns, even though these horns may develop in the same individual. We discuss our results in the context of the developmental biology of secondary sexual traits in beetles. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 473–480.     

Combined monte carlo and molecular dynamics simulation of fully hydrated dioleyl and palmitoyl-oleyl phosphatidylcholine lipid bilayers

We have applied a new equilibration procedure for the atomic level simulation of a hydrated lipid bilayer to hydrated bilayers of dioleyl-phosphatidylcholine (DOPC) and palmitoyl-oleyl phosphatidylcholine (POPC). The procedure consists of alternating molecular dynamics trajectory calculations in a constant surface tension and temperature ensemble with configurational bias Monte Carlo moves to different regions of the configuration space of the bilayer in a constant volume and temperature ensemble. The procedure is applied to bilayers of 128 molecules of POPC with 4628 water molecules, and 128 molecules of DOPC with 4825 water molecules. Progress toward equilibration is almost three times as fast in central processing unit (CPU) time compared with a purely molecular dynamics (MD) simulation. Equilibration is complete, as judged by the lack of energy drift in 200-ps runs of continuous MD. After the equilibrium state was reached, as determined by agreement between the simulation volume per lipid molecule with experiment, continuous MD was run in an ensemble in which the lateral area was restrained to fluctuate about a mean value and a pressure of 1 atm applied normal to the bilayer surface. Three separate continuous MD runs, 200 ps in duration each, separated by 10,000 CBMC steps, were carried out for each system. Properties of the systems were calculated and averaged over the three separate runs. Results of the simulations are presented and compared with experimental data and with other recent simulations of POPC and DOPC. Analysis of the hydration environment in the headgroups supports a mechanism by which unsaturation contributes to reduced transition temperatures. In this view, the relatively horizontal orientation of the unsaturated bond increases the area per lipid, resulting in increased water penetration between the headgroups. As a result the headgroup-headgroup interactions are attenuated and shielded, and this contributes to the lowered transition temperature.     

17β-Estradiol responsiveness of MCF-7 laboratory strains is dependent on an autocrine signal activating the IGF type I receptor

Background  

Human MCF-7 cells have been studied extensively as a model for breast cancer cell growth. Many reports have established that serum-starved MCF-7 cells can be induced to proliferate upon the sole addition of 17β-estradiol (E2). However, the extent of the mitogenic response to E2 varies in different MCF-7 strains and may even be absent. In this study we compared the E2-sensitivity of three MCF-7 laboratory strains.     

Seed dormancy release and germination characteristics of <i>Corispermum lehmannianum</i> Bunge,an endemic species in the Gurbantunggut desert of China

Seed dormancy release and germination of Corispermum lehmannianum Bunge were tested using various treatments: temperature, cold stratification, gibberelins (GA3), dry storage and sand burial. Results showed that temperature and light did not affect the germination of fresh seeds, cold stratification and GA3 could improve seed germination, whereas dry storage and sand burial did not. The germination percentage was highest at 35/20 °C after the cold stratification and GA3 treatments. Corispermum lehmannianum seeds were classified as non-deep, Type-2, physiological dormancy (PD), whose seed dormancy could be released by cold stratification and GA3.     

Psychosocial perception of adults with onychomycosis: a blinded,controlled comparison of 1,017 adult Hong Kong residents with or without onychomycosis

Background

A survey was conducted amongst 1,017 Hong Kong residents ages 18 and over to determine their knowledge of fungal nail infections (onychomycosis) and the psychosocial impact of the disease on the relationships, social lives and careers of sufferers.

Methods

The Fungal Nail Perception Survey was conducted by email and online between May 29th and June 10th, 2013. Participants were shown three photographs of people with and without onychomycosis of the toenails. Respondents were asked ten questions (repeated for each picture) to ascertain their perceptions of the people in the pictures. Questions were related to perceptions around the ability of sufferers and non-sufferers to form relationships with others, social activities of sufferers and non-sufferers, perceptions of the effect of the disease on the potential for career success, and awareness of fungal nail disease and health. The sub-population who themselves suffered from onychomycosis were asked about self-perception as well as their perception of others with onychomycosis.

Results

Compared with non-sufferers, survey respondents perceived those with onychomycosis as less likely to be able to form good relationships. They also indicated that they would be more likely to exclude sufferers than non-sufferers from social activities and that they would be more likely to feel uncomfortable when sitting or standing beside an infected person than beside an uninfected person. Respondents perceived people with onychomycosis to be less able to perform well in their chosen career than with someone without onychomycosis. Interestingly, those respondents who themselves were infected felt socially excluded, upset and embarrassed by their infection.

Conclusions

Onychomycosis may lead to stigmatization and social exclusion. Misconceptions of onychomycosis are high and education about the disease needs to be improved. Early recognition and treatment of the disease is essential to avoid complications and improve treatment outcomes, which would lead to reduced psychosocial impact on those with fungal nail infections.