Sensitivity assessment of sea lice to chemotherapeutants: Current bioassays and best practices.

Traditional bioassays are still necessary to test sensitivity of sea lice species to chemotherapeutants, but the methodology applied by the different scientists has varied over time in respect to that proposed in "Sea lice resistance to chemotherapeutants: A handbook in resistance management" (2006). These divergences motivated the organization of a workshop during the Sea Lice 2016 conference "Standardization of traditional bioassay process by sharing best practices." There was an agreement by the attendants to update the handbook. The objective of this article is to provide a baseline analysis of the methodology for traditional bioassays and to identify procedures that need to be addressed to standardize the protocol. The methodology was divided into the following steps: bioassay design; material and equipment; sea lice collection, transportation and laboratory reception; preparation of dilution; parasite exposure; response evaluation; data analysis; and reporting. Information from the presentations of the workshop, and also from other studies, allowed for the identification of procedures inside a given step that need to be standardized as they were reported to be performed differently by the different working groups. Bioassay design and response evaluation were the targeted steps where more procedures need to be analysed and agreed upon.

Endohelminth parasites from salmonids in intensive culture from southern Chile.

A total of 228 salmonids (90 Oncorhynchus mykiss, 48 Oncorhynchus kisutch, and 90 Salmo salar) from 8 intensive aquaculture centers in the south of Chile were examined for endohelminths parasites between December 2008 and May 2009. The body cavities of 2 O. mykiss were infected by Diphyllobothrium sp. plerocercoids (prevalence: 6.7%, mean intensity: 1.0, mean abundance: 0.07) from the Lake Tarahuin hatchery on the south of Chiloé Island. Also, tetraphyllidean plerocercoids (prevalence: 3.3%, mean intensity: 1, mean abundance: 0.03) and fourth-stage larvae of Hysterothylacium aduncum (prevalence: 6.7%, mean intensity: 1, mean abundance 0.07) were observed in O. kisutch from a marine hatchery in Chiloé. The occurrences of Diphyllobothrium sp. in a lake and a tetraphyllidean plerocercoid from marine cultured salmonid in Chiloé are reported for first time. No muscular infection by helminths was recorded in the fish examined.

A conserved mode of head segmentation in arthropods revealed by the expression pattern of Hox genes in a spider.

Chelicerates constitute a basic arthropod group with fossil representatives from as early as the Cambrian period. Embryonic development and the subdivision of the segmented body region into a prosoma and an opisthosoma are very similar in all extant chelicerates. The mode of head segmentation, however, has long been controversial. Although all other arthropod groups show a subdivision of the head region into six segments, the chelicerates are thought to have the first antennal segment missing. To examine this problem on a molecular level, we have compared the expression pattern of Hox genes in the spider Cupiennius salei with the pattern known from insects. Surprisingly, we find that the anterior expression borders of the Hox genes are in the same register and the same relative segmental position as in Drosophila. This contradicts the view that the homologue of the first antennal segment is absent in the spider. Instead, our data suggest that the cheliceral segment is homologous to the first antennal segment and the pedipalpal segment is homologous to the second antennal (or intercalary) segment in arthropods. Our finding implies that chelicerates, myriapods, crustaceans, and insects share a single mode of head segmentation, reinforcing the argument for a monophyletic origin of the arthropods.

[The detection of soluble bacterial antigens studied in various pathological substances using counterimmunoelectrophoresis. Contribution to diagnosis(151 cases)]. / Recherche d'antigènes bactériens solubles dans divers produits pathologiques par contre-immuno-électrophorèse. Apport diagnostique (151 cas).

Examinations for soluble bacterial antigens using counter-immunoelectrophoresis (C.I.E.) was carried out in 151 patients suspected of suffering from various infectious syndrome were successful for S. pneumoniae, H. influenzae b, N. meningitis, sero-group B and D streptococcus. Thus meningitis and pneumonia represent those areas in which the technique is particularly useful. Apart from its rapidity--result in a hour--C.I.E., in association with bacteriology, makes possible an increase in aetiological diagnosis of 27% with H. influenzae b, 24% with S. pneumoniae and 6% with N. meningitidis (lower result by virtue of technical difficulties with sero-group B). Thus using this technique we were able to reach an aetiological diagnosis in 10 (23.8%) out of 42 cases of purulent meningitis where blind antibiotic therapy had already been given. These two advantages--rapidity and increase in aetiological diagnosis--justify the introduction of this simple technique in every medical microbiology laboratory.