"How Many Individuals Consider Themselves to Be Cell Biologists but Are Informed by the Journal That Their Work Is Not Cell Biology".

What can we gain from co-analyzing experimental cultures, regionalization, and disciplinary phenomena of late twentieth century life sciences under our historiographic looking glass? This essay investigates the potential of such a strategy for the case of cell biology after 1960. By merging perspectives from historical epistemology inspired by the work of Hans-Jörg Rheinberger with a focus on boundary work in the realm of scientific publishing, community building, and disciplinary norms, a set of understudied scientific practices is exposed. These practices, historically subsumed under the label descriptive, have been as central in cell biology as hypothesis-driven research aiming at mechanistic explanations of cellular function. Against the background of an increasing molecular-mechanistic imperative in cell biology since the late 1960s, knowledge from descriptive practices was often judged as having low value but was nonetheless frequently cited and considered essential. Investigating the underlying epistemic practices and their interactions with disciplinary gatekeeping phenomena (as policed by journals and learned societies) provides historiographic access to the plurality of experimental cultures of cell biology, scattered into many interdisciplinary research fields-with some of them only partially engaged with mechanistic questions.

Superinfection of sows with Cystoisospora suis ante partum leads to a milder course of cystoisosporosis in suckling piglets.

Cystoisospora (syn. Isospora) suis is a leading cause of diarrheal disease in neonatal piglets. To address the possibility of maternal immunization against C. suis infection six non-naïve pregnant sows were superinfected with 100,000 oocysts 2 weeks ante partum and compared to non-superinfected animals. Their piglets were infected with 1000 oocysts on the third day of life. Clinical and parasitological parameters as well as antibody titers in colostrum/milk and blood of sows and in the blood of piglets were evaluated by IFAT against sporozoites and merozoites from 2 weeks ante partum until the 35th day after birth. For IFAT two different invasive stages of C. suis were used to find possible differences between the immune response against the initially infectious stages (sporozoites) and later occurring asexual developmental stages (merozoites), which might be responsible for persisting/extraintestinal infections. IFN-γ production of PBMC and piglet splenocytes was determined by ELISPOT. Maternal superinfection resulted in increased titers of IgA, IgM and IgG in colostrum and milk as well as in the blood of sows and their piglets. Oocyst shedding and diarrhea were observed in the offspring of both groups, but piglets of superinfected sows showed significantly reduced oocyst shedding and less diarrhea. This protective effect was correlated with increased titers of antibodies, especially IgA, in colostrum, milk and blood serum of sows and piglets, and with the reactivity of splenocytes to parasite antigen. Superinfection of sows ante partum could partially protect piglets against the clinical outcome of experimental infection. Both colostrum and milk contain maternal protective substances as the effect of protection was highly correlated with antibody titers during the first 2 weeks of life. IgA in different substrates may serve as a marker for the level of protection against clinical cystoisosporosis.

Transfer of Cystoisospora suis-specific colostral antibodies and their correlation with the course of neonatal porcine cystoisosporosis.

Cystoisospora suis is the most pathogenic species of coccidia in suckling piglets, affecting them predominantly within their first three weeks of life. The clinical signs of neonatal cystoisosporosis include watery diarrhea and wasting, leading to significant economic losses for the farmer. Since neonatal piglets have an immature immune system, colostral transfer of maternal factors such as immune cells or antibodies is essential for controlling infections at that age. However, the role of C. suis-specific antibodies transferred from the sow to the piglets and possible correlations between antibody levels in the piglets acquired from colostrum with the clinical outcome of disease are currently not understood. To address this issue, 12 non-infected piglets and 14 piglets experimentally infected with C. suis on the third day of life were examined during their first four weeks of life. IgG, IgA, and IgM titers in the blood serum specific for sporozoites and merozoites of C. suis were evaluated, along with oocyst excretion and fecal consistency. Additionally, the antibody content in the colostrum and milk of three mother sows was determined. A transfer of naturally acquired C. suis-specific antibodies from sows to piglets with the colostrum could be demonstrated. Maternal antibodies in piglets' blood sera did not persist for longer than 14-21 days except for IgG which was present in high titers until the end of the study. Within 2-3 weeks after birth the onset of endogenous antibody production was noticed. Titers in blood serum showed a correlation with the severity of diarrhea which was positive for IgG and IgM (possibly due to increased consumption or loss of these antibodies) and negative for IgA. C. suis-specific mucus antibodies isolated from infected and non-infected piglets (n=6/group) on the 28th day of life were present in both groups, showing significantly higher titers of IgA and IgM in infected piglets. Maternally transferred antibodies acquired by natural infections of sows as observed in this study did not provide protection against the clinical manifestation of disease. The level and effect of transferrable maternal factors necessary for protection still need to be elucidated. However, correlations between antibody titers and fecal consistency in the piglets indicate that C. suis-specific antibodies might be useful markers for the expectable clinical severity of cystoisosporosis.

Isospora suis in an epithelial cell culture system - an in vitro model for sexual development in coccidia.

Coccidian parasites are of major importance in animal production, public health and food safety. The most frequently used representative in basic research on this group is Toxoplasma gondii. Although this parasite is well investigated there is no adequate in vitro model for its sexual development available and knowledge on this important life cycle phase is therefore scarce. The use of Isosporasuis, a sister taxon to T. gondii and the causative agent of piglet coccidiosis, could provide a solution for this. In the present study an in vitro model for neonatal porcine coccidiosis in cells representative for the in vivo situation in the piglet gut was developed and evaluated. The parasite development was investigated by light and transmission electron microscopy and optimum culture conditions were evaluated. Intestinal porcine epithelial cells (IPEC-J2) adequately representing the natural host cells supported the development of all endogenous life cycle stages of I. suis, including gametocytes and oocysts. A concentration of 5% fetal calf serum in the culture medium led to highest gametocyte densities on day 12 post infection. Low infection doses (≤1 sporozoite for 100 host cells) were best for oocyst and gametocyte development. The presented system can also be used for immunostaining with established antibodies developed against T. gondii (in our case, anti-TgIMC3 antibodies directed against the inner membrane complex 3). The complete life cycle of I. suis in a cell line representing the natural host cell type and species provides a unique model among coccidian parasites and can be used to address a wide range of topics, especially with regard to the sexual development of coccidia.

Immunohistochemical detection and quantification of T cells in the small intestine of Isospora suis-infected piglets--influence of fixation technique and intestinal segment.

Quantification of immunohistochemical results constitutes an important tool in the analysis of cells and tissue that is not readily replaced by other techniques. For reliable quantification, it is essential to consider factors such as tissue fixation and tissue sampling. We report a study on the model of the intestine of Isospora suis-infected piglets, in which we addressed (1) whether the quantity of detectable T cells in the intestinal mucosa is the same in formalin-, HOPE®-, and cryo-conserved material or whether the amounts of T cells at least correlate with one another; and (2) whether single jejunal segments differ in regard to the quantity of mucosal T cells and variability of lymphocyte infiltration. Quantification of T cells in histological sections of different parts of the jejunum of 15-22 day old piglets infected with I. suis was performed using an anti-CD3-antibody and stereological point counting. Area fractions of T-cell profiles per intestinal mucosa profile were higher in cryo-conserved samples than in HOPE®- and formalin-conserved material but no correlation between different fixations could be found. The proximal part of the jejunum contained fewer T cells compared with mid- and end-jejunum. Coefficients of variation did not differ between the intestinal segments. For quantification of T cells in the gut mucosa of piglets infected with I. suis, the cryo-conserved mid jejunum seems most suitable in cases when unbiased sampling of the complete intestine is not feasible. It is generally not possible to compare quantitative results of immunostaining in samples conserved by different methods.

Influence of toltrazuril treatment on parasitological parameters and health performance of piglets in the field--an Austrian experience.

Porcine coccidiosis caused by Isospora suis is one of the leading causes of neonatal diarrhea in suckling piglets. Currently the only registered drug for metaphylaxis is toltrazuril. To evaluate the effect of treatment on piglets from 7 Austrian farms without and 8 Austrian farms with toltrazuril application we examined oocyst excretion (including determination of oocysts per gram of feces; OPG), diarrhea (fecal score FS 1-4 with 3 and 4 being diarrhea), and general health (health score HS 1-4 with 3 and 4 describing poor health). Both groups included farms with different levels of hygiene. Samples from 265 litters without treatment, comprising 1588 individual samples, and 1548 samples from 258 treated litters were taken twice (around the 14th and the 21st day of life, respectively), examined by autofluorescence and, if positive, by McMaster counting. In both groups animals had less diarrhea and lower health scores during the second sampling but the treated piglets were always significantly healthier and had less diarrhea. The percentage of weaned piglets was higher in treated animals although this was not significant (p=0.052). In the first round of sampling 17.8% of the individual samples from untreated piglets were positive for oocysts (with a maximum prevalence on the 12-15th day of life) while in the treated piglets only 0.4% shed oocysts p<0.001). At the second sampling only 2.1% of the untreated animals and none of treated piglets excreted I. suis (p=0.083). Positive animals shed up to 8 × 10(3)OPG. There was an increased risk for infected piglets to develop diarrhea (odds ratio, OR 4.73) and poor health (OR 5.05) in untreated piglets, and poor hygiene without disinfection was identified as a risk factor for poor health (OR 1.90), diarrhea (OR 1.42) and oocyst excretion (OR 1.73). The risk of poor health (OR 2.89) and diarrhea (OR 1.44) was also increased for piglets under poor hygienic conditions receiving toltrazuril, so both metaphylaxis of coccidiosis and good hygiene are necessary to effectively control neonatal diarrhea. The costs of treatment are considerably lower than the estimated financial production losses. Therefore, treatment is recommended for farms where clinical coccidiosis is diagnosed.

Proposal of Viridibacillus gen. nov. and reclassification of Bacillus arvi, Bacillus arenosi and Bacillus neidei as Viridibacillus arvi gen. nov., comb. nov., Viridibacillus arenosi comb. nov. and Viridibacillus neidei comb. nov.

A polyphasic study was undertaken to clarify the taxonomic position of endospore-forming strains 433-D9, 433-E17 and 121-X1. BOX-PCR-generated fingerprints indicated that they may be members of a single species. 16S rRNA gene sequence similarity demonstrated that a representative of this group, 433-D9, is affiliated closely with Bacillus arvi DSM 16317(T) (100 %), Bacillus arenosi DSM 16319(T) (99.8 %) and Bacillus neidei NRRL BD-87(T) (97.1 %). Sequence similarities revealed Bacillus pycnus NRRL NRS-1691(T) and several Kurthia species as the next nearest relatives. DNA-DNA hybridization results showed that strain 433-D9 is a member of B. arvi. Detection of l-Lys-d-Asp-based peptidoglycan in strain 433-D9, B. arvi DSM 16317(T) and B. arenosi DSM 16319(T) was in agreement with their close relationship, but differentiated these strains from B. neidei NRRL BD-87(T) and B. pycnus NRRL NRS-1691(T), for which l-Lys-d-Glu was reported. A similar quinone system was detected in strains 433-D9, 433-E17, 121-X1, B. arvi DSM 16317(T), B. arenosi DSM 16319(T) and B. neidei NRRL BD-87(T). This system, unusual for bacilli, consisted of the major compound menaquinone MK-8 (69-80 %) and moderate amounts of MK-7 (19-30 %). This observation was in contrast to the predominance of MK-7 of the closest relative B. pycnus NRRL NRS-1691(T), as also reported for representatives of the closely related non-endospore-forming genus Kurthia. Strains 433-D9, B. arvi DSM 16317(T) and B. arenosi DSM 16319(T) exhibited homogeneous and discriminative polar lipid profiles and fatty acid profiles consisting of major acids i-C(15 : 0) and ai-C(15 : 0) and moderate amounts of i-C(17 : 1)omega10c and i-C(17 : 1) I/ai-C(17 : 1) B that discriminated them from closely related strains such as B. neidei NRRL BD-87(T). On the basis of clear-cut discriminative chemotaxonomic markers, we propose strains 433-D9, 433-E17 and 121-X1, B. arvi DSM 16317(T), B. arenosi DSM 16319(T) and B. neidei NRRL BD-87(T) to be reclassified within a separate genus. For this new taxon, we propose the name Viridibacillus gen. nov., and we propose the reclassification of Bacillus arvi, Bacillus arenosi and Bacillus neidei as Viridibacillus arvi gen. nov., comb. nov. (the type species of Viridibacillus, with the type strain DSM 16317(T) =LMG 22165(T)), Viridibacillus arenosi comb. nov. (type strain DSM 16319(T) =LMG 22166(T)) and Viridibacillus neidei comb. nov. (type strain NRRL BD-87(T) =DSM 15031(T) =JCM 11077(T)).

Polar lipid and fatty acid profiles--re-vitalizing old approaches as a modern tool for the classification of mycoplasmas?

A set of 20 Mollicutes strains representing different lines of descent, including the type species of the genus Mycoplasma, Mycoplasma mycoides, Acholeplasma laidlawii and a strain of Mesoplasma, were subjected to polar lipid and fatty acid analyses in order to evaluate their suitability for classification purposes within members of this group. Complex polar lipid and fatty acid profiles were detected for each examined strain. All strains contained the polar lipids phosphocholine-6'-alpha-glucopyranosyl-(1'-3)-1, 2-diacyl-glycerol (MfGL-I), 1-O-alkyl/alkenyl-2-O-acyl-glycero-3-phosphocholine (MfEL), sphingomyelin (SphM), 1-O-alkyl/alkenyl-glycero-3-phosphocholine (lysoMfEL), the unknown aminophospholipid APL1 and the cholesterol Chol2. A total of 19 strains revealed the presence of phosphatidylethanolamine (PE) and/or phosphatidylglycerol (PG), and the presence of diphosphatidylglycerol (DPG) was detected in 13 strains. The unknown aminolipid AL1 was found in the extracts of 17 strains. Unbranched saturated and unsaturated compounds predominated in the fatty acid profiles. Major fatty acids were usually C16:0, C18:0, C18:1 omega9c and 'Summed feature 5' (C18:2 omega6, 9c/C18:0 anteiso). Our results demonstrated that members of the M. mycoides cluster showed rather homogenous polar lipid and fatty acid profiles. In contrast, each of the other strains was characterized by a unique polar lipid profile and significant quantitative differences in the presence of certain fatty acids. These results indicate that analyses of both polar lipid and fatty acid profiles could be a useful tool for classification of mycoplasmas.