Satellite RNA (RNA3) of tomato black ring virus is found with one of the 2 major RNAs (RNA2) in a new capsid nucleoprotein]

Tomato Black Ring Virus (TBRV) like other NEPOviruses posseses two nucleoproteins M and B and two major RNAs, RNA1 and RNA2 respectively distributed in B and M. A new nucleoprotein has just been discovered and comprises one molecule of RNA2 associated with one molecule of RNA3. RNA3 is a small RNA of molecular weight 500,000 d considered to be a satellite RNA. Its level appears to depend on the infection stage, local or systemic. RNA3 is able to modify the relative proportions of nucleoproteins M and B and their respective RNAs. The satellite RNA, might be part of the genome and represent a monocistronic mRNA for protein capsid synthesis. However it seems perhaps more tempting to correlate TBRV-RNA3 with satellite RNA5 of certain strains of Cucumber mosaic virus.     

Demonstration of Yersinia pseudotuberculosis in in cultivated soils]

The bacteriological analysis of 37 pools of cultivated soils collected in a limited area in the Parisian district permits the isolation of 14 strains of Y. pseudotuberculosis: 9 strains are of serotype II, 3 of serotype I, 1 of serotype III, and of serotype IV. This diversity contrasts with the prevalence of serotype I in infections of man and animals and the scarcity of type III and IV in these species. The abundance of our isolates is in favour of a large distribution of the germ in this substratum, which can be considered as a potential contamination source.     

Inhibition of granulocyte-macrophage (GM) colony formation by basic polypeptides from mouse Ehrlich ascites tumor cells

Summary The polypeptides isolated from mouse Ehrlich ascites tumor cells were tested for their inhibitory activity against GM colony formation. It was found that basic polypeptides with low molecular weight evidently inhibit colony formation. Our data reveal that the tested polypeptides may show chalone activity.     

Iclusion proteins and viral proteins of the baculovirus of the dipteran Tipula paludosa (Meigen)]

Examination of the polyhedron protein by polyacrylamide gel electrophoresis shows only one polypeptide with a molecular weight of 25,500 +/- 500 daltons, while that of virion proteins reveals 13 polypeptides. No antigenic community could be demonstrated between the polyhedron protein of the Baculovirus of T. paludosa and the polyhedron protein of several other Baculoviruses.     

Nuclear envelope and nuclear matrix: interactions and dynamics

The peripheral nuclear lamina is located near the nuclear inner membrane and consists of lamin filaments and integral membrane proteins, including the lamin B receptor and various isoforms of lamina-associated polypeptides (LAP) 1 and 2. Several nuclear membrane proteins also interact with chromatin proteins BAF and Hp1. Lamins in the nuclear interior associate with at least one soluble (non-membrane-bound) LAP2 isoform named LAP2alpha. The internal lamins, together with Tpr-based filaments that connect to nuclear pore complexes, are proposed to be major structural elements of the internal nuclear matrix. We describe the structural links between the peripheral lamina and the internal nuclear matrix that are thought to be mediated by LAP2 family members, filament protein Tpr and nucleoporin Nup153. These findings are discussed in relation to human diseases that arise from mutations in nuclear lamina proteins.     

Presence of viruses in a strain of mycoplasma pulmonis.

Filtrates prepared from heavily grown agar cultures of M. pulmonis strain Negroni-52 formed plaques on lawns of A. laidlawii strain JAl but not on those of M. pulmonis strains Ash or Negroni-52. The plaque-forming agent proved to be rod-shaped particles morphologically identical with mycoplasmavirus group 1. Evidence supporting the conclusion that the virus originated from Negroni-52 has been obtained. Electron microscopy revelaed that Negroni-52 is also a carrier of long-tailed phage-like particles.     

Influence of sulfhydryl reagents on the structural and molecular organization of crayfish photoreceptor microvilli

Summary SDS-polyacrylamide gel electrophoresis of isolated photoreceptor membrane from crayfish compound eyes in the absence and presence of the sulfhydryl-reducing agent 2-mercaptoethanol revealed major qualitative and quantitative differences in electrophoretic behaviour of polypeptides. Two peptides of 37 and 69 KD show abnormal migration patterns under the experimental conditions, indicating a possible significance of disulfide bridges for the structural integrity of invertebrate photoreceptor membrane.     

Über den Auslesewert chromosomaler Strukturtypen vonDrosophila subobscura unter experimentellen Bedingungen

Summary In artificial populations ofDrosophila subobscura, arising from the mating of strains of different origin and different chromosomal structure, it was demonstrated that also in the X-chromosome an adaptive equilibrium is reached between two different structural types, although heterosis only acts in the females. There is a significant excess of females in the hybrid-generation in both reciprocal matings, especially at low temperature. The sexratio of the pure strains is 1:1. The excess may be caused by a selective advantage of the structurally heterozygous females in competition with the hemizygous males.     

Structure and dynamics of rotary V<Subscript>1</Subscript> motor

Rotary ATPases are unique rotary molecular motors that function as energy conversion machines. Among all known rotary ATPases, F₁-ATPase is the best characterized rotary molecular motor. There are many high-resolution crystal structures and the rotation dynamics have been investigated in detail by extensive single-molecule studies. In contrast, knowledge on the structure and rotation dynamics of V₁-ATPase, another rotary ATPase, has been limited. However, recent high-resolution structural studies and single-molecule studies on V₁-ATPase have provided new insights on how the catalytic sites in this molecular motor change its conformation during rotation driven by ATP hydrolysis. In this review, we summarize recent information on the structural features and rotary dynamics of V₁-ATPase revealed from structural and single-molecule approaches and discuss the possible chemomechanical coupling scheme of V₁-ATPase with a focus on differences between rotary molecular motors.     

Biomedicine and Diseases: Review¶Assembling the human immunodeficiency virus type 1

Retroviral assembly proceeds through a series of concerted events that lead to the formation and release of infectious virion particles from the infected cell. Upon translation, structural proteins are targeted to the plasma membrane where they accumulate. There, the nascent particle forces the plasma membrane to form a bud, which pinches off releasing the virion particle from the cell. In this review we describe the molecular mechanisms now known to be behind the process of virion assembly. In particular, we focus on the human immunodeficiency virus type 1, the prototype member of the lentivirus subfamily of the Retroviridae.     

Presence of viruses in a strain ofMycoplasma pulmonis

Summary Filtrates prepared from heavily grown agar cultures ofM. pulmonis strain Negroni-52 formed plaques on lawns ofA. laidlawii strain JA1 but not on those ofM. pulmonis strains Ash or Negroni-52. The plaque-forming agent proved to be rod-shaped particles morphologically identical with mycoplasmavirus group 1. Evidence supporting the conclusion that the virus originated from Negroni-52 has been obtained. Electron microscopy revelaed that Negroni-52 is also a carrier of long-tailed phage-like particles.     

Cellular contaminants and structural proteins of Rous sarcoma virus (RSV), studied by polyacrylamide gel electrophoresis]

The number of polypeptides in highly purified preparations of RSV, of two different subgroups, produced in culture, has been compared to the polypeptides present in the supernatant of uninfected cultures and processed in identical manner. The analysis of PAGE-SDS shows that from 13 to 18 polypeptides present in viral preparations may be cellular contaminants. Fewer contaminating polypeptides are found in the myeloblastosis virus purified from plasma of Chicken.     

Molecular aspects of the epidemiology of virus disease

With regard to molecular epidemiology, influenza A viruses belong to the best-studied virus systems. At least two large reservoirs of influenza A viruses have been built up in nature, one in humans and another one in water fowls. The latter one is very heterogenous, consisting of viruses belonging to 13 hemagglutinin (HA) and 9 neuraminidase (NA) subtypes in almost all possible combinations. The segmented structure of the influenza virus genome allows the creation of new influenza strains by reassortment. By replacement of the HA gene of human strains new pandemic viruses can be generated (antigenic shift). The particular structure of the HA enables the human influenza A-viruses to create variants which can escape the immune response of the host (antigenic drift). The nucleoprotein is responsible for keeping those two large reservoirs apart. Mixing of genes of viruses from these two reservoirs seems to happen predominantly by double infection of pigs, which apparently are tolerant for infection by either human or avian influenza viruses. The molecular mechanisms described for influenza viruses can be explained by the particular structure of their genome and their components and cannot be generalized. Each virus has developed its own strategy to multiply and to spread.     

Aggrecan, aging and assembly in articular cartilage

The primary function of articular cartilage to act as a self-renewing, low frictional material that can distribute load efficiently at joints is critically dependent upon the composition and organisation of the extracellular matrix. Aggrecan is a major component of the extracellular matrix, forming high molecular weight aggregates necessary for the hydration of cartilage and to meet its weight-bearing mechanical demands. Aggregate assembly is a highly ordered process requiring the formation of a ternary complex between aggrecan, link protein and hyaluronan. There is extensive age-associated heterogeneity in the structure and molecular stoichiometry of these components in adult human articular cartilage, resulting in diverse populations of complexes with a range of stabilities that have implications for cartilage mechanobiology and integrity. Recent findings have demonstrated that aggrecan can form ligands with other matrix proteins. These findings provide new insights into mechanisms for aggregate assembly and functional protein networks in different cartilage compartments with maturation and aging.     

Intrinsic disorder in proteins involved in amyotrophic lateral sclerosis

Five structurally and functionally different proteins, an enzyme superoxide dismutase 1 (SOD1), a TAR-DNA binding protein-43 (TDP-43), an RNA-binding protein FUS, a cofilin-binding protein C9orf72, and polypeptides generated as a result of its intronic hexanucleotide expansions, and to lesser degree actin-binding profilin-1 (PFN1), are considered to be the major drivers of amyotrophic lateral sclerosis. One of the features common to these proteins is the presence of significant levels of intrinsic disorder. The goal of this study is to consider these neurodegeneration-related proteins from the intrinsic disorder perspective. To this end, we employed a broad set of computational tools for intrinsic disorder analysis and conducted intensive literature search to gain information on the structural peculiarities of SOD1, TDP-43, FUS, C9orf72, and PFN1 and their intrinsic disorder predispositions, and the roles of intrinsic disorder in their normal and pathological functions.     

Using genetically-defined rodent strains for the identification of hippocampal traits relevant for two-way avoidance behavior: a non-invasive approach

Genetically-defined rodent strains permit the identification of hippocampal traits which are of functional relevance for the performance of two-way avoidance behavior. This is exemplified here by analyzing the relationship between infrapyramidal mossy fibers (a tiny projection terminating upon the basal dendrites of hippocampal pyramidal neurons) and two-way avoidance learning in about 800 animals. The necessary steps include 1) identification of structural traits sensitive to selective breeding for extremes in two-way avoidance, 2) testing the robustness of the associations found by studying individual and genetical correlations between hippocampal traits and behavior, 3) establishing causal relationships by Mendelian crossing of strains with extreme structural traits and studying the behavioral consequences of such structural 'randomization', 4) confirming causal relationships by manipulating the structural variable in inbred (isogenic) strains, thereby eliminating the possibility of genetic linkage, and 5) ruling out the possibility of spurious associations by studying the correlations between the hippocampal trait and other behaviors known to depend on hippocampal functioning. In comparison with the classical lesion approach for identifying relationships between brain and behavior, the present procedure appears to be superior in two aspects: it is non-invasive, and it focuses automatically on those brain traits which are used by natural selection to shape behaviorally-defined animal populations, i.e., it reveals the natural regulators of behavior.     

Isolation of a pathogenic rhabdovirus of brown trout (Salmo trutta L., 1766)]

A Rhabdovirus pathogenic both for Rainbow and Brown Trout has been isolated from Brown Trout suffering heavy mortalities associated with muscular haemorrages and necrotic lesions of kidney and spleen. According to seroneutralization tests and host range, this virus appears to be different from the other known salmonids rhabdoviruses. Upon the basis of its in vitro gross characteristics, it is identical to Viral Haemorragic Septicemia Virus (VHS), F1 serotype, but differs from Infectious Hematopo?etic Necrosis and VHS type II viruses.     

Use of Cowan strain I of Staphylococcus aureus for radio-immunological determination of retrovirus proteins]

The use of Staphylococcus aureus for the radio-immunoassay of C-type virus polypeptides provided very specific results and proved to present several advantages over the classical methods of precipitation of immune complexes.