Dehydration does not affect the radial pressures produced by the earthworm Aporrectodea caliginosa

As a soil dries, the earthworms in that soil dehydrate and become less active. Moisture stress may weaken an earthworm, lowering the radial pressure that the animal can produce. This possibility was investigated for the earthworm Aporrectodea caliginosa (Savigny). Pressures were compared for saturated earthworms (worms taken from saturated soil) and stressed earthworms (worms that had been partially dehydrated by leaving them in dry soil). A load cell was used to record the forces that earthworms produced as they moved through artificial burrows (holes that had been drilled through blocks of aluminium or Perspex). The radial pressure was calculated using the forces exerted and the dimensions of the artificial burrows. There was a negative correlation between burrow diameter and radial pressure, although radial pressure was independent of the length of the block through which the earthworms had burrowed. The highest radial pressures were produced by the anterior segments of the animal. Partial dehydration caused the earthworms to become quiescent, but did not decrease the radial pressure that the earthworms produced. It is suggested that coelomic fluid is retained in the anterior segments while the rest of the animal dehydrates. Dehydrated earthworms became lethargic, and we suggest that lethargy is due to the loss of coelomic fluid from the posterior segments. Coelomic fluid is known to be lost through dorsal pores. In burrowing species of earthworm such as Aporrectodea caliginosa, these pores are only present on the posterior segments.

Coxsackievirus B3-associated myocardial pathology and viral load reduced by recombinant soluble human decay-accelerating factor in mice

Coxsackievirus B3 (CVB3) infection can result in myocarditis, which in turn may lead to a protracted immune response and subsequent dilated cardiomyopathy. Human decay-accelerating factor (DAF), a binding receptor for CVB3, was synthesized as a soluble IgG1-Fc fusion protein (DAF-Fc). In vitro, DAF-Fc was able to inhibit complement activity and block infection by CVB3, although blockade of infection varied widely among strains of CVB3. To determine the effects of DAF-Fc in vivo, 40 adolescent A/J mice were infected with a myopathic strain of CVB3 and given DAF-Fc treatment 3 days before infection, during infection, or 3 days after infection; the mice were compared with virus alone and sham-infected animals. Sections of heart, spleen, kidney, pancreas, and liver were stained with hematoxylin and eosin and submitted to in situ hybridization for both positive-strand and negative-strand viral RNA to determine the extent of myocarditis and viral infection, respectively. Salient histopathologic features, including myocardial lesion area, cell death, calcification and inflammatory cell infiltration, pancreatitis, and hepatitis were scored without knowledge of the experimental groups. DAF-Fc treatment of mice either preceding or concurrent with CVB3 infection resulted in a significant decrease in myocardial lesion area and cell death and a reduction in the presence of viral RNA. All DAF-Fc treatment groups had reduced infectious CVB3 recoverable from the heart after infection. DAF-Fc may be a novel therapeutic agent for active myocarditis and acute dilated cardiomyopathy if given early in the infectious period, although more studies are needed to determine its mechanism and efficacy.

Quantification of mitochondrial DNA mutation load

Mitochondrial DNA (mtDNA) mutations are an important cause of genetic disease and have been proposed to play a role in the ageing process. Quantification of total mtDNA mutation load in ageing tissues is difficult as mutational events are rare in a background of wild-type molecules, and detection of individual mutated molecules is beyond the sensitivity of most sequencing based techniques. The methods currently most commonly used to document the incidence of mtDNA point mutations in ageing include post-PCR cloning, single-molecule PCR and the random mutation capture assay. The mtDNA mutation load obtained by these different techniques varies by orders of magnitude, but direct comparison of the three techniques on the same ageing human tissue has not been performed. We assess the procedures and practicalities involved in each of these three assays and discuss the results obtained by investigation of mutation loads in colonic mucosal biopsies from ten human subjects.

Quantification of mitochondrial DNA mutation load

Mitochondrial DNA (mtDNA) mutations are an important cause of genetic disease and have been proposed to play a role in the ageing process. Quantification of total mtDNA mutation load in ageing tissues is difficult as mutational events are rare in a background of wild-type molecules, and detection of individual mutated molecules is beyond the sensitivity of most sequencing based techniques. The methods currently most commonly used to document the incidence of mtDNA point mutations in ageing include post-PCR cloning, single-molecule PCR and the random mutation capture assay. The mtDNA mutation load obtained by these different techniques varies by orders of magnitude, but direct comparison of the three techniques on the same ageing human tissue has not been performed. We assess the procedures and practicalities involved in each of these three assays and discuss the results obtained by investigation of mutation loads in colonic mucosal biopsies from ten human subjects.