Leopold Auerbach's heritage in the field of morphology and embryology with special emphasis on gametogenesis of invertebrates.

Plexus myentericus Auerbachi and Friedreich-Auerbach disease are widely used eponyms that are associated with eminent morphologist Leopold Auerbach (1828-1897), whose life is relatively little known due to limited access to his German-written XIX century biographies and lack of English biographical papers about him in world literature. Hereby we focused on hardly known achievements of Leopold Auerbach in the field of gametogenesis and embryology of invertebrates. Auerbach did not only confirm unicellularity of amoebas, which was previously discovered. He described cleavage of fertilized eggs of Ascaris nigrovenosa and Strongylus auricularis. Moreover, his accurate descriptions on germination of Paracentrotus lividus inspired a recognized German zoologist Oscar Hertwig (1849-1922). Auerbach also profoundly studied an encystation of Oxytricha pellionella on morphological grounds. His descriptions referred to karyokinesis as well as oogenesis and spermatogenesis to discover conjugations of spermatozoa in pairs in the epididymis of a beetle, Dytiscus marginalis. He also distinguished two types of spermatozoa of Paludina vivipara: the hairlike-shaped (German: haarförmigen) and the worm-shaped (wurmförmigen) ones of these fresh water (river) snails. His studies on germination (including cell division during cleavage of nematodes) inspired the others, e.g., Oscar Hertwig, and following generations to conclude that "Auerbach deserves the credit for having provided the first scientific foundation for modern teaching on fertilization" according to professor of anatomy Gustav Born (1851-1900) at Breslau University.

Microfocus X-ray CT (microCT) Imaging of Actinia equina (Cnidaria), Harmothoe sp. (Annelida), and Xenoturbella japonica (Xenacoelomorpha).

Traditionally, biologists have had to rely on destructive methods such as sectioning in order to investigate the internal structures of opaque organisms. Non-destructive microfocus X-ray computed tomography (microCT) imaging has become a powerful and emerging protocol in biology, due to technological advancements in sample staining methods and innovations in microCT hardware, processing computers, and data analysis software. However, this protocol is not commonly used, as it is in the medical and industrial fields. One of the reasons for this limited use is the lack of a simple and comprehensible manual that covers all of the necessary steps: sample collection, fixation, staining, mounting, scanning, and data analyses. Another reason is the vast diversity of metazoans, particularly marine invertebrates. Because of marine invertebrates' diverse sizes, morphologies, and physiologies, it is crucial to adjust experimental conditions and hardware configurations at each step, depending on the sample. Here, microCT imaging methods are explained in detail using three phylogenetically diverse marine invertebrates: Actinia equina (Anthozoa, Cnidaria), Harmothoe sp. (Polychaeta, Annelida), and Xenoturbella japonica (Xenoturbellida, Xenacoelomorpha). Suggestions on performing microCT imaging on various animals are also provided.

Methods for Image-based Surveys of Benthic Macroinvertebrates and Their Habitat Exemplified by the Drop Camera Survey for the Atlantic Sea Scallop.

Underwater imaging has long been used in the field of marine ecology but decreasing costs of high-resolution cameras and data storage have made the approach more practical than in the past. Image-based surveys allow for initial samples to be revisited and are non-invasive compared to traditional survey methods that typically involve nets or dredges. Protocols for image-based surveys can vary greatly but should be driven by target species behavior and survey objectives. To demonstrate this, we describe our most recent methods for an Atlantic sea scallop (Placopecten magellanicus) drop camera survey to provide a procedural example and representative results. The procedure is divided into three critical steps that include survey design, data collection, and data products. The influence of scallop behavior and the survey goal of providing an independent assessment of the U.S. sea scallop resource on the survey procedure are then discussed in the context of generalizing the method. Overall, the broad applicability and flexibility of the University of Massachusetts Dartmouth School for Marine Science and Technology (SMAST) drop camera survey demonstrates the method could be generalized and applied to a variety of sessile invertebrates or habitat focused research.

Correlation of phospholipase and proteinase production of Candida with in vivo pathogenicity in Galleria mellonella

An essential factor to the virulence of the genus Candida is the ability to produce enzymes and this may be crucial in the establishment of fungal infections. AIM:This study investigated in vitro enzymatic activities of Candida species and their virulence in an in vivo Galleria mellonella experimental model. METHODS: Twenty-four clinical strains of Candida spp. isolated from the human oral cavity were evaluated, including the following species: C. albicans, C. dubliniensis, C. glabrata, C. tropicalis, C. krusei, C. parapsilosis, C. norvegensis, C. lusitaniae and C. guilliermondii. All Candida strains were tested in vitro for production of proteinase and phospholipase. The Candida strains were also injected into Galleria mellonella larvae to induce experimental candidiasis, and after 24 hours, the survival rate was assessed. RESULTS: Phospholipase and proteinase activity were observed in 100% of the C. albicans strains. In the non-albicans species, proteinase and phospholipase activity were observed in 25 and 43% of the studied strains, respectively. The most pathogenic Candida species in G. mellonella were C. albicans, C. dubliniensis and C. lusitaniae, whereas C. glabrata was the least virulent species. Furthermore, a positive significant correlation was found between both enzymatic activities with virulence in G. mellonella. CONCLUSIONS: The virulence of Candida strains in G. mellonella is related to the quantity of proteinases and phospholipases production of each strain.

Pathogenicity and virulence.

Invertebrate pathologists have multiple definitions for the terms pathogenicity and virulence, and these definitions vary across disciplines that focus on host-pathogen interactions. We surveyed various literatures, including plant pathology, invertebrate pathology, evolutionary biology, and medicine, and found most define pathogenicity as the broader term, which incorporates virulence. Virulence is seen as the severity of disease manifestation that can only be measured in infected individuals. These definitions readily apply to both lethal and non-lethal diseases. Invertebrate pathologists commonly use dose-response bioassays to estimate LD(50) or LC(50) (dose or concentration needed to kill 50% of hosts exposed). These bioassays measure pathogenicity if the bioassay includes a transmission component, and measure virulence if the bioassay is measured in infected individuals only. Another common bioassay estimate is LT(50) (median time to death of infected hosts), which is a measure of virulence as long as survivors are not included in its calculation.

[Cephalic region damage in the nemertean Lineus ruber by the orthonectid Intoshia linei]. / Porazhenie golovnogo otdela nemertiny Lineus ruber plazmodiiami ortonektidy Intoshia linei.

Previous investigators believed, that the plasmodia of Intoshia linei can affect all part of nemerteans body except the cephalic lobe. Our results indicate that in strongly infected worms mature plasmodia can settle inside of the cephalic region and form the large conglomerates. Common places of plasmodia localization in hosts are not only the tegument, connective tissue, gonads, muscles of body wall and proboscis, but also the nervous tissue. We found a lot of the mature plasmodia in all four lobes of the nemerteans brain and in the lateral nerve trunks. Furthermore the plasmodia can settle in the cerebral organs, in the walls of blood lacunae and rhynchcoel. In spite of the strong invasion of the cephalic lobe we have never observed a plasmodial outgrowths in the tegument of this region. This phenomena can be explained by the assumption, that plasmodia usually intrude into the cephalic region relatively late and have no time to form outgrowths up to the moment when starts the emission of adult males and females in the rest parts of nemertean body. Moreover, single parasite cells were repeatedly found in the host tissue near the mature plasmodium. These cells had few cytoplasm and large vesicular nuclei, which were very similar in size to the nuclei of the host cells. General morphology of single cells was very similar to the generative cells of the plasmodium. At present, the function of these cells is not evident, but we believe, they appearance is concerned with the proliferation of plasmodiuma and agglomeration of the parasite in the body of Lineus ruber.

[The multiyear dynamics of infection and of the distribution of 3 species of Orthonectida in the White and Barents seas]. / Mnogoletnaia dinamika zarazheniia i raspredeleniia trekh vidov ortonektid na Belom i Barentsevom moriakh.

Annual dynamics and distribution of three Orthonectida species--Intoshia variabili, I. linei, Rhopalura littoralis--have been studied in the invertebrates in the White and Barents seas. Throughout years of observations orthonectids show high stability, constant percent of infection and permanent location of the same spots. Mosaic pattern of their distribution has been revealed. Possible causes of difficulties in finding orthonectids in nature are discussed.

Intestinal parasites of raccoons (Procyon lotor) from southwest British Columbia.

This is the first extensive survey of metazoan parasites (particularly of the roundworm Baylisascaris procyonis) from the intestines of raccoons in British Columbia. The sample collected in 1997-1998 consisted of 82 raccoons that had been sick or had been killed accidentally by automobiles. Fifteen parasite taxa were found: 3 nematodes, 9 digenetic trematodes, 2 acanthocephalans and 1 cestode. Ten of these parasites constitute new host records for raccoons, including 4 digenetic trematodes that have been reported in marine birds and mammals on the Pacific Coast of North America. Baylisascaris procyonis infected 61% of the raccoons with a mean intensity of 27. The high rate of infection indicates a large potential for environmental contamination and, thus, human and animal exposure to infectious eggs. Prevention of larva migrans is discussed, particularly for people in contact with raccoons in wildlife rehabilitation centers.

[Acanthamoeba, Naegleria and invertebrates in wet areas of physiotherapy equipment in hospitals]. / Acanthamoeben, Naeglerien und Invertebraten in Feuchtbereichen von Physiotherapieeinrichtungen in Krankenhäusern.

In the course of investigations on the occurrence of primary free-living amoebae in different aquatic habitats, especially Naegleria and Acanthamoeba, we now investigated the moist areas in physiotherapeutic departments of 10 hospitals. As a result 61% of the swabs taken in those areas were positive with one or several species of amoebae cultivated on NN-agar according to Page. Among many other species observed during this study we were able to isolate 47 strains of Acanthamoeba and only two strains of Naegleria. The Naegleria-strains did not appear to be thermophilic. Therefore they are part of the N. gruberi-complex, which is considered to include only non pathogenic strains. Six from 47 strains of Acanthamoebae isolated revealed pathogenic characters as demonstrated in the MIT (Mice inoculation test). As a remarkable result four of these 6 strains with proven pathogenicity were not thermophilic at + 40 degrees C. Eventually all strains even not being thermophilic should in future be tested on pathogenicity. Additionally, nematodes and rotifers were isolated from several samples.