Detection of Staphylococcal Enterotoxin A,B, and C in Milk By an Elisa Procedure

Enterotoxigenic reference strains of Staphylococcus aureus were cultivated in sterile whole and skim milk for 18 h at 37°G. Staphylococcal enterotoxin A, B, and C were detected directly in the milk by an enzyme linked immunosorbent assay (ELISA), sensitive down to 1 ng/ml. Enterotoxins in the range of 1 ng–20 µg/ml milk were detected without any concentration or extraction. Skim and whole milk were almost identical as medium for enterotoxin production.     

Microclimates and water budget of algae,lichens and a moss on some nunataks in Queen Maud Land

During the Norwegian Antarctic Expedition of 1984–1985, land parties worked in the area of Mühlig-Hofmannfjella and Gjelsvikfjella in Queen Maud Land (5° 20E, 1° 37W, 1000–1600 m a.s.l.). The nunataks in this area, which represents one of the climatic limits for terrestrial life on earth, is among those areas absorbing the highest quantity of shortwave radiation during a period of 24 h in summer. In spite of this the air temperature never, or very seldom, exceeds 0° C. The limiting factor for photosynthesis over most of the summer was water availability. Melt-water plays an important role in spring. During rest of the growth season, water from condensation is probably the most important water source for plants. On calm nights the rate of condensation during 6 h may reach 0.5 mm, which constitutes only 10%–30% of daily potential evapotranspiration. Plants situated in narrow clefts or shielded by stone blocks have the highest rate of potential photosynthesis. These locations are shielded from direct solar radiation most of the time, but the radiation from surrounding stone surfaces is higher than from the atmosphere and heat loss by turbulence is smaller than for exposed locations. These locations also probably have the highest rate of actual photosynthesis.     

Starvation survival and body composition in mammals with particular reference toHomo sapiens

A computer model of body mass and composition in relation to gross energy balance is constructed. The model is built using conventional empirical physiological formulae rather than statistical or analytical mathematical techniques. The model is applied to the Minnesota and other experiments and produces as good or better simulations of observed values of changes in body weight than reported for other formulae or models. Alternative physiological mechanisms concerning metabolic adaptions to starvation, changes in time activity budgets and the energy equivalents of weight loss offer equally good simulations of experimental results. The present analysis highlights the survival value of a basal metabolic depression during starvation and indicates an optimal body composition of 10% mobilizable fat for starvation survival for a 70 kg man. Proper quantification of the effects of the physiological mechanisms involved depends on new experimental data, however. Long term continuous monitoring of time activity budgets are a necessary part of such experiments.     

Immunohistochemistry of epithelial cell markers in normal and pathological colon mucosa

Summary The purpose of this study was to examine whether formal-dehyde-fixed tissue may afford reproducible and reliable immunhistochemical results when carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA are evaluated semiquantitatively in normal and pathological colon specimens. Proximate tissue samples were processed by routine formalin fixation and by a cold-ethanol fixation method, respectively, and the immunofluorescence intensities obtained for the three antigens were scored. After formalin fixation SC and epithelial IgA were generally undetectable and also the staining for CEA was markedly reduced compared with that seen after ethanol fixation. Significant antigenic unmasking was obtained by enzyme treatment of the formalin-fixed tissue sections-resulting in enhanced staining for SC and epithelial IgA but not consistently so for CEA. With this modification scores from duplicate tissue samples processed by the two methods showed significant correlations for all the three epithelial markers; small amounts of CEA and epithelial IgA, and especially SC, nevertheless remained undetectable after formalin fixation. This result should be taken into account when epithelial markers are applied in studies of premalignant lesions of the colon where minor changes in the antigen pattern may be of diagnostic importance.     

The model organism as a system: integrating 'omics' data sets

Various technologies can be used to produce genome-scale, or 'omics', data sets that provide systems-level measurements for virtually all types of cellular components in a model organism. These data yield unprecedented views of the cellular inner workings. However, this abundance of information also presents many hurdles, the main one being the extraction of discernable biological meaning from multiple omics data sets. Nevertheless, researchers are rising to the challenge by using omics data integration to address fundamental biological questions that would increase our understanding of systems as a whole.     

Deep sequencing reveals clonal evolution patterns and mutation events associated with relapse in B-cell lymphomas

Background

Molecular mechanisms associated with frequent relapse of diffuse large B-cell lymphoma (DLBCL) are poorly defined. It is especially unclear how primary tumor clonal heterogeneity contributes to relapse. Here, we explore unique features of B-cell lymphomas - VDJ recombination and somatic hypermutation - to address this question.

Results

We performed high-throughput sequencing of rearranged VDJ junctions in 14 pairs of matched diagnosis-relapse tumors, among which 7 pairs were further characterized by exome sequencing. We identify two distinctive modes of clonal evolution of DLBCL relapse: an early-divergent mode in which clonally related diagnosis and relapse tumors diverged early and developed in parallel; and a late-divergent mode in which relapse tumors developed directly from diagnosis tumors with minor divergence. By examining mutation patterns in the context of phylogenetic information provided by VDJ junctions, we identified mutations in epigenetic modifiers such as KMT2D as potential early driving events in lymphomagenesis and immune escape alterations as relapse-associated events.

Conclusions

Altogether, our study for the first time provides important evidence that DLBCL relapse may result from multiple, distinct tumor evolutionary mechanisms, providing rationale for therapies for each mechanism. Moreover, this study highlights the urgent need to understand the driving roles of epigenetic modifier mutations in lymphomagenesis, and immune surveillance factor genetic lesions in relapse.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-014-0432-0) contains supplementary material, which is available to authorized users.     

Spermatogenesis and related plasma androgen levels in Atlantic halibut (Hippoglossus hippoglossus L.)

Spermatogenesis in male Atlantic halibut (Hippoglossus hippoglossus L.) was investigated by sampling blood plasma and testicular tissue from 15-39-month-old fish. The experiment covered a period in which all fish reached puberty and completed sexual maturation at least once. The germinal compartment in Atlantic halibut testis appears to be organized in branching lobules of the unrestricted spermatogonial type, because spermatocysts with spermatogonia were found throughout the testis. Spermatogenesis was characterized histologically, and staged according to the most advanced type of germ cell present: spermatogonia (Stage I), spermatogonia and spermatocytes (Stage II), spermatogonia, spermatocytes and spermatids (Stage III), spermatogonia, spermatocytes, spermatids and spermatozoa (Stage IV), and regressing testis (Stage V). Three phases could be distinguished: first, an initial phase with low levels of circulating testosterone (T; quantified by RIA) and 11-ketotestosterone (11-KT; quantified by ELISA), spermatogonial proliferation, and subsequently the initiation of meiosis marked by the formation of spermatocytes (Stage I and II). Secondly, a phase with increasing T and 11-KT levels and with haploid germ cells including spermatozoa present in the testis (Stage III and IV). Thirdly, a phase with low T and 11-KT levels and a regressing testis with Sertoli cells displaying signs of phagocytotic activity (Stage V). Circulating levels of 11-KT were at least four-fold higher than those of T during all stages of spermatogenesis. Increasing plasma levels of T and 11-KT were associated with increasing testicular mass throughout the reproductive cycle. The absolute level of, or the relation between, testis growth and circulating androgens were not significantly different in first time spawners compared to fish that underwent their second spawning season. These results provide reference levels for Atlantic halibut spermatogenesis.