Plasmodium sasai n. sp. from the Japanese Lizard Takydromus tachydromoides

SYNOPSIS. This is the 1st reptilian Plasmodium to be described from eastern Asia. It is apparently of limited geographic distribution. Experimental infections may result in the production of more parasites than red cells in the circulating blood. A single erythrocyte may be infected by as many as 11 parasites. Despite the heavy parasitemia and destruction of erythrocytes, the hosts are apparently not affected by the infection. Mature schizonts are frequently fan-shaped; they produce 7–17 merozoites. The asexual cycle has a high degree of synchrony.     

Cryptosporidium parvum merozoites share neutralization-sensitive epitopes with sporozoites

Sporozoites and merozoites are stages in the life cycle of Cryptosporidium parvum that can cyclically infect intestinal cells, causing persistent infection and severe diarrhea in immunodeficient patients. Infection by sporozoites can be neutralized by surface-reactive mAb. We show that merozoite infectivity can also be neutralized by surface-reactive mAb. To do this, viable C. parvum merozoites were isolated by differential and isopycnic. centrifugation, and distinguished from sporozoites by transmission electron microscopy. Differential reactivity with a panel of seven mAb was used to determine the amount of sporozoite contamination in isolated merozoite preparations. The isolated merozoites were distinguished from sporozoites (p less than 0.0001) by four sporozoite-specific mAb (16.332, 16.502, 17.25, and 18.357) in an indirect immunofluorescence assay. Three mAb (16.29, 17.41, and 18.44) consistently reacted with both merozoites and sporozoites. Isolated merozoites were infectious for neonatal mice when administered by intraintestinal injection. Infectivity for mice was significantly neutralized (p less than 0.05) when 1 to 2 x 10(5) merozoites were incubated with sporozoite-neutralizing mAb 17.41 or 18.44, before inoculation. Merozoites incubated with an isotype control mAb remained infectious for neonatal mice. We conclude that C. parvum merozoites share neutralization-sensitive epitopes with sporozoites.     

Ordination and significance testing of microbial community composition derived from terminal restriction fragment length polymorphisms: application of multivariate statistics

Terminal restriction fragment length polymorphism (T-RFLP) is increasingly being used to examine microbial community structure and accordingly, a range of approaches have been used to analyze data sets. A number of published reports have included data and results that were statistically flawed or lacked rigorous statistical testing. A range of simple, yet powerful techniques are available to examine community data, however their use is seldom, if ever, discussed in microbial literature. We describe an approach that overcomes some of the problems associated with analyzing community datasets and offer an approach that makes data interpretation simple and effective. The Bray-Curtis coefficient is suggested as an ideal coefficient to be used for the construction of similarity matrices. Its strengths include its ability to deal with data sets containing multiple blocks of zeros in a meaningful manner. Non-metric multi-dimensional scaling is described as a powerful, yet easily interpreted method to examine community patterns based on T-RFLP data. Importantly, we describe the use of significance testing of data sets to allow quantitative assessment of similarity, removing subjectivity in comparing complex data sets. Finally, we introduce a quantitative measure of sample dispersion and suggest its usefulness in describing site heterogeneity. This revised version was published online in June 2006 with corrections to the Cover Date.     

Phospholemman is a substrate for myotonic dystrophy protein kinase

The genetic abnormality in myotonic muscular dystrophy, multiple CTG repeats lie upstream of a gene that encodes a novel protein kinase, myotonic dystrophy protein kinase (DMPK). Phospholemman (PLM), a major membrane substrate for phosphorylation by protein kinases A and C, induces Cl currents (I(Cl(PLM))) when expressed in Xenopus oocytes. To test the idea that PLM is a substrate for DMPK, we measured in vitro phosphorylation of purified PLM by DMPK. To assess the functional effects of PLM phosphorylation we compared I(Cl(PLM)) in Xenopus oocytes expressing PLM alone to currents in oocytes co-expressing DMPK, and examined the effect of DMPK on oocyte membrane PLM expression. We found that PLM is indeed a good substrate for DMPK in vitro. Co-expression of DMPK with PLM in oocytes resulted in a reduction in I(Cl(PLM)). This was most likely a specific effect of phosphorylation of PLM by DMPK, as the effect was not present in oocytes expressing a phos(-) PLM mutant in which all potential phosphorylation had been disabled by Ser --> Ala substitution. The biophysical characteristics of I(Cl(PLM)) were not changed by DMPK or by the phos(-) mutation. Co-expression of DMPK reduced the expression of PLM in oocyte membranes, suggesting a possible mechanism for the observed reduction in I(Cl(PLM)) amplitude. These data show that PLM is a substrate for phosphorylation by DMPK and provide functional evidence for modulation of PLM function by phosphorylation.     

Longline Fisheries and Foraging Distribution of Flesh-Footed Shearwaters in Eastern Australia

ABSTRACT Incidental seabird mortality associated with bycatch during longline commercial fishing is a conservation concern. An initial step to estimating likelihood of seabird bycatch and conceiving conservation strategies is determining amount of overlap between foraging birds and commercial fishing effort, identifying oceanographic features associated with foraging birds, and quantifying dive characteristics. We tracked 24 adult flesh-footed shearwaters (Puffinus carneipes) breeding on Lord Howe Island located east of Australia during incubation and early and late chick-rearing periods from 6 January to 17 April 2005. At-sea foraging distribution of flesh-footed shearwaters was primarily confined within the jurisdictional Australian Fishing Zone. Foraging was strongly associated with sea-surface temperature >24°C. Spatial and temporal overlap of longline fishing with foraging shearwaters varied throughout the breeding season, but was greatest (63% overlap) during early chick-rearing. Mean maximum distance reached from the breeding colony during a foraging event was 804 km (SD = 280) from Lord Howe Island. Foraging behavior was strongly diurnal, with 91% of dives occurring during daylight, and most dives (77%) were <5 m. Given that longline fishing and flesh-footed shearwaters overlap substantially, the Australian Fisheries Management Authority should consider implementing additional regulations to further reduce bycatch. Conservation strategies such as setting longlines at nights may reduce flesh-footed shearwater bycatch.     

Use of SSCP to improve the efficiency of microsatellite identification from microsatellite‐enriched libraries

An inefficient aspect of marker identification from microsatellite‐enriched libraries is the proportion of clones with identical sequences. This can substantially increase the number of clones that need to be sequenced in order to identify a sufficient number of microsatellite loci. We propose the use of single‐stranded conformation polymorphism (SSCP) analysis to identify unique clones prior to sequencing. We used this approach prior to sequencing from microsatellite‐enriched libraries for three marine invertebrate species and were able to obtain a given number of unique clone sequences for only 28% of the sequencing effort that would have been required without SSCP screening.     

Human creatine kinase: isolation and sequence analysis of cDNA clones for the B subunit, development of subunit specific probes and determination of gene copy number

cDNA clones for human B creatine kinase were isolated from human brain and placenta libraries. The entire coding and 3' untranslated regions, as well as 23 bp of the 5' untranslated region were sequenced. Complete sequence identity was found among the clones, with the exception of an area of heterogeneity among the 3' untranslated region of the brain and placenta clones. A 77.7% nucleotide sequence identity was found between the coding region of human B creatine kinase and our previously reported human M creatine kinase. In contrast, no homology was found in the 3' untranslated regions. Probes were constructed from the nonconserved 3' untranslated regions of human M and B creatine kinase and were shown to be highly specific. Southern transfers of total genomic DNA derived from human placenta and digested to completion with several restriction enzymes were probed with the MCK and BCK specific probes producing single hybridization bands. These results suggest that creatine kinase M and B are single copy genes in the human genome.