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At least 19 recordsLinked to original sources
PubMed1976

Influenza A virus interaction with murine lymphocytes. I. The influence of influenza virus A/Japan 305 (H2N2) on the pattern of migration of recirculating lymphocytes.

The effect of influenza virus A/Japan 305 (H2N2) on the path of migration of recirculating lymphocytes has been studied. 51Cr-labeled rat thoracic duct lymphocytes (TDL) were incubated with virus at 37 degrees C for 1 hr and then infused i.v. into syngeneic recipients which were killed 1 hr later. Virus-treated TDL accumulated in the liver and their recovery in lymph nodes and spleen was severely reduced. Changes in lymphocytes induced by virus developed rapidly and were evident after incubation for only 15 min. UV-irradiated virus altered the pattern of lymphocyte localization but attachment of heat-inactivated virus to lymphocytes in vitro had no effect on their distribution in vivo. Evidence was obtained that some virus-treated TDL, initially sequestered in the liver, subsequently recovered their ability to circulate normally. Recovery was not complete and a population of cells failed to regain their ability to home into lymph nodes. Evidence is also presented demonstrating that influenza virus affected the homing properties of both T and B cells. It is suggested that aberrations in lymphocyte homing were mediated by the viral neuraminidase which induces changes in the cell membrane leading to their accumulation in the liver.

Animals↗
PubMed1976

New temperate bacteriophage for Bacillus subtilis, rho 11.

A new temperate bacteriophage, rho11, isolated by J. Hoch, has been characterized. This new phage is very similar to the temperate phage phi3T in size (380 nm), host range, homoimmunity, DNA buoyant density (1.694 g/ml), antigenicity, and molecular weight (around 6.0 X 10(7)) as determined in gels. Like phi3T, rho11 converts thymine auxotrophs to prototrophy at high frequency (250 out of 250 tested). Phage rho11 differs from phi3T in plaque morphology and in the endonuclease R-EcoRI digest pattern. Sixteen of the 20 rho11 DNA fragments have migration patterns corresponding to those of the 21 fragments of phi3T. The close similarities yet clear differences between these phages suggest that the two phages have a common ancestor.

Bacillus subtilis↗
PubMed1979

Immunochemical cross-reactions between type III group B Streptococcus and type 14 Streptococcus pneumoniae.

Serological cross-reactions between certain streptococci and some serotypes of Streptococcus pneumoniae have been reported. These studies detail the serological cross-reactivity observed between hot HCl-extracted group b streptococcus type III (GBS III) antigens and S. pneumoniae type 14 (Pn 14) polysaccharide. Similar electrophoretic migration patterns of GBS III and Pn 14 were observed when either type-specific BGS III antisera or pneumococcal omniserum was utilized to precipitate these antigens. Both the GBS III antigen and the Pn 14 polysaccharide migrated toward the cathode, whereas all other pneumococcal polysaccharides migrated toward the anode. No cross-reactions were observed between GBS III antisera and the 11 other types of pneumococcal polysaccharides. Lines of identity were observed between type-specific GBS III antisera and monospecific Pn 14 antiserum with either GBS III antigens or purified Pn 14 polysaccharide. The cross-reacting antigens of GBS III and Pn 14 appear to be identical by immunodiffusion and immunoelectrophoresis.

Antigens, Bacterial↗
PubMed2026

Genomic reconstruction of the Pakistani Roma reveals dual South Asian ancestry, medieval bottlenecks, and the early dispersal routes of the Romani people.

The Roma people represent one of the largest and most historically enigmatic diasporas in Eurasia, illuminating human migration patterns and cultural resilience across continents. Despite extensive research on European Roma as the diaspora endpoint, the genetic legacy of their putative South Asian source populations remains critically underexplored, leaving fundamental gaps in understanding the pre-diaspora demographic structure and early dispersal dynamics. This study uniquely positions Pakistani Roma as a potential ancestral reservoir, offering a rare window into the pre-migration phase distinct from derived European Roma populations shaped by centuries of post-dispersal admixture. We analyze 82 Pakistani Roma from Punjab using high-resolution genome-wide SNP data and comprehensive mitochondrial haplogroup profiling to reconstruct their genetic origins, population structure, and historical trajectory. Analyses reveal a dual ancestry profile comprising 50-82% Indus Valley related, 20-30% Onge related, and up to 26% Steppe derived components, with three distinct subgroups exhibiting varying affinities along a South Asian to Central Western Eurasian continuum reflecting jati-like endogamy. A severe demographic bottleneck ~800 years ago coincides with medieval socio-political upheavals, while major Eurasian admixture is dated to ~660 years ago. Mitochondrial haplogroups H (45.12%) and M (26.83%) underscore dual maternal influences from West and South Eurasia. Pakistani Roma retain substantially higher South Asian ancestry than their European counterparts, establishing them as a genetically distinct population preserving the ancestral pre-diaspora state. These findings redefine the Romani origin narrative and underscore the critical value of understudied South Asian minorities in reconstructing complex human migration pathways and diaspora formation mechanisms.

Humans↗
PubMed1979

A human breast tumor cell line (BT-474) that supports mouse mammary tumor virus replication.

A human breast tumor cell line BT-474 derived from an invasive ductal carcinoma was experimentally infected in vitro with a mouse mammary tumor virus from the TIII strain (RIII-MuMTV). The virus that replicated in the human cells was characterized as a mouse virus by immunofluorescence, electron microscopy and the presence of a specific RNA-directed DNA polymerase. The cells themselves were human as per the karyotype and isoenzyme migration patterns. It is concluded that human cells are susceptible to the mouse mammary tumor virus and can, eventually, support its replication.

Antigens, Viral↗
PubMed1977

Immunochemical evidence for an additional H-2 region closely linked to H-2D.

Anti-H-2 reagents have been tested on solubilized spleen cell preparations in combinations expected to be specific for D region products. Two different types of molecules were detected. One showed the expected reactivity with both antisera to private and antisera to public specificities. However, an additional molecule was detected which reacted only with antisera to public specificities. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis migration patterns indicated that both products have a similar molecular size of approximately 45,000 daltons. The data therefore present chemical evidence for the existence of a third H-2-associated gene product of 45,000 mol wt in addition to the classical H-2K and H-2D antigens.

Animals↗
PubMed2025

SISTEM: simulation of tumor evolution, metastasis, and DNA-seq data under genotype-driven selection.

SUMMARY: SISTEM is a software package and mathematical framework for simulating tumor evolution and cell migrations at single-cell resolution. Unlike existing frameworks which simulate cancer cell populations under the neutral coalescent or using simple birth-death models, SISTEM simulates tumor populations under somatic clonal selection using an agent-based framework. SISTEM can generate mutation profiles, read counts, and DNA sequencing reads along with ground truth cell lineages and migration graphs under a number of easily customizable mutation and selection models. For improved realism, SISTEM allows for cell fitness to be driven by genomic events of various scales including single nucleotide variants, segmental gains and losses, whole-chromosomal and chromosome-arm aberrations, and whole-genome duplications. SISTEM also includes numerous migration models to simulate metastatic cancers, facilitating the exploration and evaluation of diverse migration patterns. AVAILABILITY AND IMPLEMENTATION: SISTEM is written in Python and is freely available open-source under GNU GPLv3 from: https://github.com/samsonweiner/sistem.

Software↗
PubMed1977

Radioimmunoassay for the antigenic determinants of cholera toxin and its components.

A radioimmunoassay procedure is described for the detection of cholera toxin and its component polypeptide chains. Cholera toxin, A subunit, B subunit, alpha chain, and gamma chain were iodinated by the chloramine T procedure. Radiolabeling did not significantly alter the polyacrylamide electrophoretic migration patterns of the toxin or its components. Moreover, radiolabeled toxin, B subunit, and alpha chain preparations retained substantial ability to bind to intestinal mucosal homogenates. The minimal amount of antitoxin detectable with radiolabeled toxin was 0.04 antitoxin units/ml. Substitution of radiolabeled B subunit, A subunit, and alpha chain for radiolabeled toxin decreased the sensitivity of the test. Radiolabeled gamma chain did not bind to the antitoxin preparation. Competitive inhibition studies, with titrated anti-choleragen serum and radiolabeled toxin or components, indicated that the minimum concentration of toxin detectable was 7.0 x 10(-8) mumol/ml at a 90% inhibition level. The A subunit and alpha chain preparations inhibited the binding of the radiolabeled B subunit to antitoxin sites. Conversely, B subunit inhibited the binding of radiolabeled A subunit and alpha chain to antitoxin. The gamma chain did not show any reaction with antitoxin or cross-reaction with either whole toxin or its components. These results strongly suggest that the A subunit and the alpha chain contain antigenic determinant(s) that are common to the B subunit. The B subunit (beta chain) and the alpha chain of cholera toxin may therefore contain region(s) of chemical similarity.

Antigens, Bacterial↗
PubMed1977

Rabbit intestinal fluid stimulation by an enterotoxigenic factor of Staphylococcus aureus.

An exoprotein of Staphylococcus aureus 100 that elicited a positive ileal loop response in the rabbit model was investigated in this study. The protein, as it occurred in the culture supernatant fluid, could be detected initially in the late log phase of growth under aerobic and anaerobic conditions. It was stable under acidic conditions to pH 2.0 after 24 h at 4 degrees C. Thirty-minute treatments at 80 degrees C destroyed the ileal loop activity whereas similar trials at 70 degrees C had no effect. Although preparations of staphylococcal enterotoxins purified by other investigators did not produce positive ileal loops, the enterotoxigenic activity of the S. aureus 100 supernatant fluid could be neutralized by antisera prepared against enterotoxins A and B. Throughout purification studies, the active moiety reacted serologically with antiserum A. Polyacrylamide gel electrophoresis of the partially purified protein produced migration patterns nearly identical to those of enterotoxin A.

Animals↗
PubMed1978

Different behaviour of 19S thyroglobulin extracted from normal thyroid, simple goitre and toxic goitre in polyacrylamide slab gel isoelectric focusing.

19S thyroglobulin (19S TG) was isolated from normal thyroids, simple goitres and one case of toxic goitre (Graves' disease). With isoelectric focusing on polyacrylamide gel slabs (pH 4--6) several bands for each specimen were detected. The migration patterns of the toxic goitre 19S TG were clearly different from the patterns of normal 19S TG and simple goitre 19S TG.

Electrophoresis, Polyacrylamide Gel↗
PubMed1978

[Molecular weight of lipovitellins during egg development in the crustacean amphipod Orchestia gammarella (Pallas)].

Egg lipovitellins of Orchestia gammarella tested by electrophoresis on gels of different acrylamide concentrations, following the procedure of Hedrick and Smith (1968), display a migration pattern identical to that of proteins with molecular weights of congruent to 3.2 x 10(5) (lipovitellin I) and congruent to 5.5 x 10(5) (lipovitellin II) respectively. Since their molecular weight remains constant during embryogenesis, the changes of their relative mobility in disc gels indicates alterations in their ionic charges.

Animals↗
PubMed1975

Maturation of B lymphocytes in the rat. II. Subpopulations of virgin B lymphocytes in the spleen and thoracic duct lymph.

Thoracic duct and spleen cells of normal (unimmunized) adult rats were fractionated according to size by 1 times G velocity sedimentation. Fractions were tested for their ability to restore the adoptive antibody response of irradiated hosts to horse spleen ferritin. A constant source of T cells (small numbers of unfractionated thoracic duct cells) was added to each fraction in order to monitor the B cell activity of the latter. Although large and small cell fractions of the spleen showed restorative activity, only the small cell fractions of the thoracic duct lymph showed activity. The turnover rate of the spleen cell fractions was determined by treating donors with high specific-activity 3H-thymidine for 48 hr before splenectomy. Rapidly dividing cells are preferentially killed by this treatment. The results suggest that a considerable proportion of large, intermediate, and small virgin B cells turn over within 48 hr. The cell surface of the various spleen cell fractions was examined for the presence of immunoglobulin (Ig) and a receptor for complement. The percentage of Ig-bearing cells in the large cell fractions was similar to the percentage of cells bearing IgM and a receptor for complement. However, the majority of Ig-bearing cells in the small cell fractions did not show the latter two surface markers. Experiments with the fluorescence-activated cell sorter showed that the large functionally active B cells bore surface IgM. The experimental findings suggest that there are subpopulations of virgin B cells in the spleen of the adult rat which differ with respect to size, migration pattern, turnover rate, and cell surface characteristics. The relationship of these cells to one another is discussed in the framework of an antigen-independent model of B cell maturation in the rat.

Animals↗
PubMed1979

The development of the hippocampus and dentate gyrus in normal and reeler mice.

The histogenesis, the time of origin and the pattern of migration of the cells in the hippocampus and dentate gyrus, have been studied in normal and reeler mice. The earliest indication of a defect in the reeler hippocampus is seen on the fifteenth embryonic day (E15) which is at least 24 hours after the first indication of a defect in the neocortex. It is not until E18, that the dentate gyrus shows signs of its incipient abnormality. It appears then, that in both the hippocampus and the dentate gyrus the gene defect first manifests itself at the stage at which the definitive cellular layers are assembled. Experiments involving the injection of 3H-thymidine (3H-TdR) at different developmental stages have confirmed that the site and rate of cellular proliferation in the reeler hippocampus and dentate gyrus are normal, as is the initial pattern of cell migration. However, in the reeler dentate gyrus, most postnatal cell proliferation occurs ectopically and in the hippocampus the normal "inside-out" sequence of neurogenesis is reversed, the earliest pyramidal cells generated coming to lie superficially within the stratum pyramidale and the later formed cells being added at progressively deeper levels. There is no discernible gradient in the time of origin of the granule cells in the radial dimension of the reeler dentate gyrus, whereas there is an obvious "outside-in" gradient in the normal animal. The characteristic gradients in cell proliferation seen in the transverse and longitudinal dimensions of the normal dentate gyrus are, however, also evident in the reeler mouse. Taken together, these observations suggest that the reeler gene exerts its effect on neuronal position only in the radial dimension, and does so at a stage of development subsequent to the proliferation and initial migration of the relevant neurons. Timm's sulfide silver preparations indicate that the characteristic staining patterns seen in the dentate gyrus and hippocampus appear at the same time, and mature at the same rate in normal and reeler mice.

Animals↗
PubMed2025

SimHumanity: Using SLiM 5.0 to run whole-genome simulations of human evolution.

The reconstruction of human evolutionary history has undergone repeated advances, each made possible by methodological innovations. In recent decades, genetic and genomic data played a central role in the reconstruction of major evolutionary events such as the out-of-Africa migration, and genetic simulations of human evolutionary history have come to play a major role in testing more specific hypotheses including proposed patterns of migration and admixture with archaic hominins. Increasing computational power has allowed human evolutionary history to be modeled at ever-larger scales, but simulations that encompass the complete human genome, including sex chromosomes and mitochondrial DNA, have been difficult due to the lack of support for whole-genome models in commonly used evolutionary simulation frameworks. With the recent introduction of SLiM 5 such simulations are now straightforward to construct, allowing the easy simulation of humans at whole-genome scale under different demographic models and evolutionary dynamics. We here present three versions of a reusable, customizable, open-source SLiM 5 model for simulating the molecular evolution of the full human genome. We also show some simple analyses of results from the model, to illustrate its utility. We hope this model, which we have nicknamed "SimHumanity" in jest, will facilitate further progress in the field of human evolutionary simulations.

SLiM↗
PubMed2025

Migration strategies, connectivity and corridor features of the partial migrant little bustard (Tetrax tetrax) across the Iberian Peninsula.

The study of migration ecology is crucial for understanding the factors and pressures affecting migratory species. Here, we studied the migratory ecology of the little bustard (Tetrax tetrax), a steppe bird that has suffered a sharp decline over recent decades, mainly due to agricultural intensification. Using 105 adult birds tagged across the main Iberian regions where the species is present (Alentejo, Extremadura, Ebro Valley, Northern Plateau, Southern Plateau and Guadalquivir Valley), we analysed the ratio of migratory and resident birds in each population and assessed their connectivity during the three main migratory periods (summer, winter and pre-breeding). Additionally, we describe the features of the migrations recorded in terms of length, duration and day period. Our results corroborate that little bustards can be considered partial migrants across Iberia, although the proportion of residents versus migrants varied between populations: the Alentejo (94.74%) and Northern Plateau (93.75%) had the highest proportion of migrants, followed by Guadalquivir Valley (81.82%), Extremadura (65.38%), Southern Plateau (55.56%) and Ebro Valley (25.93%). Migratory connectivity varied between periods: the pre-breeding and summering migrations showed a trend to move northwards, while birds moved southwards for winter. Regarding the migratory corridors obtained from the 253 migrations identified, we found three main routes: one corridor that connects the Northern Plateau with the western part of the Southern Plateau and Extremadura, another one that connects the Southern Plateau, Extremadura, Alentejo and Guadalquivir Valley, and one corridor that concentrates migrations within the Ebro Valley, and between the Ebro Valley and the Southern Plateau. Finally, analyses showed that little bustards migrate at night through areas dominated by herbaceous cover (avoiding tree-covered land and water bodies) and of low elevation and terrain roughness. Our results highlight the importance of developing an international and inter-regional conservation strategy to protect not only the breeding and wintering quarters, but also this endangered species' migratory corridors, thus supporting the viability of the metapopulation.

Brownian bridge kernel↗
PubMed1979

Rapid change of chromomeric and pairing patterns of polytene chromosome tips in D. melanogaster: migration of polytene-nonpolytene transition zone?

The high variability of chromomeric patterns in near-terminal regions of polytene chromosome arms has been explored in a number of races, strains and hybrids of Drosophila melanogaster. Traditional explanations for tip differences between strains (differential compaction of chromatin, somatic or germinal deletion) are examined and, in the light of the reported observations, rejected. The range of polytene tip variability and rates of change in wild races are greater than has been supposed: strains formerly considered to be terminally deleted appear to gain terminal bands; others, formerly considered normal, appear to have lost them. Strains with high cell-to-cell tip variability are also described. Cell-to-cell variations, as well as much of the observed rapid changes in tip appearance, are probably due to heritable differences in the location of an abrupt transition zone between polytene and nonpolytene chromatin. A quantitative relationship between the amount of certain subterminal bands present and the frequency of tip association of nonhomologous chromosomes is shown and its possible significance for chromosome is shown and its possible for chromosome pairing discussed.

Animals↗
PubMed1977

A new variant of glucosephosphate isomerase deficiency: GPI-Kortrijk.

A new case of glucosephosphate isomerase deficiency in a Belgian family is described. The activity of the enzyme was decreased to about 25-30% of the normal value. Characterization of the defect enzyme showed a decreased thermostability. Heating of the enzyme at 45 degrees C showed a loss of activity of 50% after 90 min. The pH-optimum and the KM-value for fructose 6-phosphate were normal. The electrophoretic pattern showed a faster migration. The variant described here differs from all known variants. Therefore we propose to give to this new variant the name GPI-Kortrijk.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed2025

The new frontier in understanding human and mammalian brain development.

Neurodevelopmental disorders that cause cognitive, behavioural or motor impairments affect around 15% of children and adolescents worldwide1, with diagnoses of profound autism and attention deficit hyperactivity disorder increasing in the USA and contributing to a major economic burden2,3. Yet the origins and mechanisms of these conditions remain poorly understood, limiting progress in therapies. Comprehensive cell atlases of the developing human brain, alongside those of model organisms such as mice and non-human primates, are now providing high-resolution measures of gene expression, cell-type abundance and spatial distribution. In this Perspective, we highlight recent studies that have identified novel developmental cell populations, revealed conserved and divergent patterns of cell genesis, migration and maturation across species, and begun testing hypotheses that link them to processes ranging from transcriptional control of cell fate specification to the emergence of complex behaviours. We present remaining conceptual and technical challenges and provide an outlook on how further studies of human and mammalian brain development can empower a deeper understanding of neurodevelopmental and neuropsychiatric disorders. Future efforts expanding to additional developmental stages, including adolescence, as well as whole-brain, multimodal and cross-species integration, will yield new insights into how development shapes the brain. These atlases promise to serve as essential references for unravelling mechanisms of brain function and disease vulnerability, and for advancing precision medicine.

Humans↗