A comparison of the intestinal helminth communities of Equidae in Southern Africa

The intestinal helminth communities of 8 horses, 12 donkeys, 21 Hartmann's mountain zebras, and 44 Burchell's zebras were compared using the original data from 6 studies in South Africa and Namibia. Necropsy and worm recovery techniques were comparable between the studies. Sixty helminth species (58 nematode, 1 cestode, and 1 trematode species) were recorded. There were significant differences in the helminth community structures of the 4 Equus species. The helminth communities of the 2 closely related zebra subspecies were most similar, and they jointly shared 7 helminth species with donkeys and only 1 with horses. Geographic variation and host-mixing contributed to the helminth species composition. Multiple confamilial species infections were the norm in the donkeys and zebra subspecies, and no single-species infection was recorded for the Strongylidae. Congeneric species were commonly recorded in 3 genera (Cyathostomum, Cylicocyclus, and Cylicostephanus). The shape of the occupancy frequency distributions for the donkeys and zebra subspecies was multimodal, with no clear satellite or core modes. Despite the presence of environmental variability and comparatively low parasite-host specificity, the phylogenetic signal within Equus helminth communities remains strong.     

Ethological analyses of the effects of naloxone and the opiate antagonist ICI 154, 129 on social interactions in male house mice

The influences of the mu blocker naloxone and the novel opioid delta receptor antagonist ICI, 154, 129 on videotaped encounters between individually-housed, male Swiss mice and anosmic male ‘standard opponents’ were assessed using a variety of ethological analyses. The effects of drugs were studied on individual elements and on the times allocated by subjects to broad categories of behaviour. Neither of the drugs significantly altered times allocated to broad categories of behaviour. Both doses of both compounds significantly increased the incidences of some ‘fearful’/defensive postures. A more detailed analysis considered the effects of the drugs on the sequences of postures used in the resident's behaviour. This involved the generation of ‘dendrograms’ which provided support for the view that both naloxone and ICI 154, 129 altered the associations between behavioural elements seen in saline controls (especially at higher doses) and that the effects of these antagonists were qualitatively different.     

A fourth gene from the Candida albicans CDR family of ABC transporters

Using primers derived from a region of the Candida albicans CDR1 (Candida drug resistance) gene that is conserved in other ABC (ATP-binding cassette) transporters, a DNA fragment from a previously unknown CDR gene was obtained by polymerase chain reaction (PCR). After screening a C. albicans genomic library with this fragment as a probe, the complete CDR4 gene was isolated and sequenced. CDR4 codes for a putative ABC transporter of 1490 amino acids with a high degree of homology to Cdr1p, Cdr2p and Cdr3p from C. albicans (62, 59 and 57% amino acid sequence identity, respectively). Cdr4p has a predicted structure typical for cluster I.1 of yeast ABC transporters, characterized by two homologous halves, each comprising an N-terminal hydrophilic domain with consensus sequences for ATP binding and a C-terminal hydrophobic domain with six transmembrane helices. In contrast to the CDR1/CDR2 genes, the genetic structure of the CDR4 gene was conserved in 59 C. albicans isolates from six different patients. Northern hybridization analysis showed that the CDR4 gene was expressed in most isolates, but no correlation between CDR4 mRNA levels and the degree of fluconazole resistance of the isolates was found. In addition, a C. albicans mutant in which both copies of the CDR4 gene were disrupted by insertional mutagenesis was not hypersusceptible to fluconazole as compared to the parent strain. Unlike CDR1 and CDR2, CDR4 does not, therefore, seem to be involved in fluconazole resistance in C. albicans.     

Effects of depth, sediment and grazers on the degradation of drifting filamentous algae (Cladophora glomerata and Pilayella littoralis)

Eutrophication in the northern Baltic Sea promotes growth of annual filamentous algae. The algae detach, gather at the bottom and give rise to algal mats of varying size, density, composition and condition. Dense mats of filamentous algae induce anoxia, which in turn leads to faunal mortality. By a set of field experiments, we have studied the fate of the abundant Cladophora glomerata after detaching from the rocky substrate, and the effect of water depth and sediment on its decay. Further, we have studied the importance of common mesograzers (Gammarus and Idotea) on the rate of degradation of C. glomerata and Pilayella littoralis.Our results show that loose algae at shallow sites (8 m) decompose faster than algae in deeper (18 m) areas. Drifting C. glomerata on the sediment is more rapidly broken down and dissolved than algae floating in the water column, which depends on higher microbiological activity. Dominant amphipods (Gammarus spp) colonise near-shore drift algae quickly, and juvenile bivalves (Cerastoderma glaucum) utilise algae in the water column for settling. Moderate natural densities of grazers (Gammarus spp and Idotea baltica) in the drifting algae did not increase the degradation rates of C. glomerata and P. littoralis. C. glomerata was completely decomposed in 4 months.Our experiments demonstrate the effects of position (depth, water/sediment) and grazing on the degradation of drifting filamentous algae. Mass developments of opportunistic algae occur annually in the study area, and information on the destiny of detached drift algae may help us to predict their longevity and the damage they cause, and hence, to decide on long-term measures needed to improve environmental conditions.     

Microfluidic-based enzymatic on-chip labeling of miRNAs

Small noncoding RNAs (sncRNAs) have moved from oddity to recognized important players in gene regulation. Next generation sequencing approaches discover more and more such molecules from a variety of different groups, but flexible tools translating this sequence information into affordable high-throughput assays are missing. Here we describe a microfluidic primer extension assay (MPEA) for the detection of sncRNAs on highly flexible microfluidic microarrays which combines several beneficial parameters: it can effortless incorporate any new sequence information; it is sensitive enough to work with as little as 20ng of total RNA and has a high level of specificity owing to a combination of a conventional hybridization assay and an enzymatic elongation step. Importantly, no labeling step is needed before hybridization and - because of its high sensitivity - no amplification is required. Both aspects ensure that no bias is introduced by such processes. Although the assay is exemplified with miRNAs, the flexibility of the technology platform allows the analysis of any type of sncRNA, such as piRNAs.