Male sleeping aggregations of solitary oil-collecting bees in Brazil (Centridini, Tapinotaspidini, and Tetrapediini; Hymenoptera: Apidae).

Males of solitary bees usually spend the night in clusters on small branches of plants, cavities and flowers. The individuals usually return to the same location each evening during their life, exhibiting site fidelity to a particular plant. We report on the sleeping roosts of the males of some oil-collecting bees of the genera Centris, Paratetrapedia, Lanthanomelissa, Monoeca, and Tetrapedia, as well as the host plants. We discuss the role of the male clusters to the associated plants.

Documenting the diet in ancient human populations through stable isotope analysis of hair.

Fundamental to the understanding of human history is the ability to make interpretations based on artefacts and other remains which are used to gather information about an ancient population. Sequestered in the organic matrices of these remains can be information, for example, concerning incidence of disease, genetic defects and diet. Stable isotopic compositions, especially those made on isolates of collagen from bones, have been used to help suggest principal dietary components. A significant problem in the use of collagen is its long-term stability, and the possibility of isotopic alteration during early diagenesis, or through contaminating condensation reactions. In this study, we suggest that a commonly overlooked material, human hair, may represent an ideal material to be used in addressing human diets of ancient civilizations. Through the analysis of the amino-acid composition of modern hair, as well as samples that were subjected to radiation (thus simulating ageing of the hair) and hair from humans that is up to 5200 years old, we have observed little in the way of chemical change. The principal amino acids observed in all of these samples are essentially identical in relative abundances and content. Dominating the compositions are serine, glutamic acid, threonine, glycine and leucine, respectively accounting for approximately 15%, 17%, 10%, 8% and 8% of the total hydrolysable amino acids. Even minor components (for example, alanine, valine, isoleucine) show similar constancy between the samples of different ages. This constancy clearly indicates minimal alteration of the amino-acid composition of the hair. Further, it would indicate that hair is well preserved and is amenable to isotopic analysis as a tool for distinguishing sources of nutrition. Based on this observation, we have isotopically characterized modern individuals for whom the diet has been documented. Both stable nitrogen and carbon isotope compositions were assessed, and together provide an indication of trophic status, and principal type (C3 or C4) of vegetation consumed. True vegans have nitrogen isotope compositions of about 7/1000 whereas humans consuming larger amounts of meat, eggs, or milk are more enriched in the heavy nitrogen isotope. We have also analysed large cross-sections of modern humans from North America and Europe to provide an indication of the variability seen in a population (the supermarket diet). There is a wide diversity in both carbon and nitrogen isotope values based at least partially on the levels of seafood, corn-fed beef and grains in the diets. Following analysis of the ancient hair, we have observed similar trends in certain ancient populations. For example, the Coptics of Egypt (1000 BP) and Chinchorro of Chile (5000-800 BP) have diets of similar diversity to those observed in the modern group but were isotopically influenced by local nutritional sources. In other ancient hair (Egyptian Late Middle Kingdom mummies, ca. 4000 BP), we have observed a much more uniform isotopic signature, indicating a more constant diet. We have also recognized a primary vegetarian component in the diet of the Neolithic Ice Man of the Oetztaler Alps (5200 BP). In certain cases, it appears that sulphur isotopes may help to further constrain dietary interpretations, owing to the good preservation and sulphur content of hair. It appears that analysis of the often-overlooked hair in archaeological sites may represent a significant new approach for understanding ancient human communities.

Molecular characterization of a new whitefly-transmissible bipartite geminivirus infecting tomato in Panama.

The nucleotide sequence of infectious clones of a tomato-infecting geminivirus from Panama [named tomato leaf curl virus (ToLCV-Pan) because of symptoms produced in infected tomato (plant stunting and mild leaf curling)] was determined. ToLCV-Pan has a bipartite genome (DNAs A and B) and computer analysis showed that the genome resembles that of other bipartite, whitefly-transmitted geminiviruses. DNA A (2584 nt) and B (2542 nt) have little sequence homology other than within the common region. ToLCV-Pan clones were introduced into Lycopersicon esculentum and infected plants developed the same symptoms as naturally infected tomatoes. Homology analysis of DNA A and B showed that ToLCV-Pan is most closely related to potato yellow mosaic virus (PYMV) from Venezuela. Pseudorecombination between ToLCV-Pan and PYMV did not give viable pseudorecombinant viruses. However, in some plants infected with the pseudorecombinant virus produced by ToLCV-Pan DNA A and PYMV DNA B, systemic movement of ToLCV-Pan DNA A was observed.

[The frontiers of 'abnormality': psychiatry and social control]. / As fronteiras da 'anormalidade': psiquiatria e controle social.

The article examines some of the main aspects governing psychiatry's role in the Brazilian political and social context at the close of the nineteenth century and beginning of the twentieth. It analyzes certain themes - civilization, race, labor, fanaticism, political dissent, sexuality - that were emphasized by specialists in their construction of a very broad notion of 'mental illness'. Through the analysis of texts produced by psychiatrists and legal experts (including dissertations written at the Faculdade de Medicina do Rio de Janeiro, reports from the Serviço de Assistência a Alienados, and works and articles by specialists), the relation between the psychiatric definition of the frontiers of 'abnormality' and efforts to implement new strategies of social control is discussed.

Nucleotide sequence of a new bipartite geminivirus isolated from the common weed Sida rhombifolia in Costa Rica.

The nucleotide sequence of infectious clones of a geminivirus from Costa Rica that infects Sida rhombifolia was determined. Sida golden mosaic virus (SiGMV-Co) has a bipartite genome (DNAs A and B). Computer analysis showed that the bipartite genome of SiGMV-Co resembles that of other whitefly-transmitted geminiviruses. The DNA A (2605 nt) and DNA B (2587 nt) components have little sequence homology other than within the common region (CR). Analysis of DNAs A and B showed that SiGMV-Co is closely related to bean dwarf mosaic virus (BDMV). SiGMV-Co was introduced via agroinoculation into seven plant species, including tomato and bean.

Nucleotide sequence evidence for the occurrence of three distinct whitefly-transmitted, Sida-infecting bipartite geminiviruses in Central America.

The nucleotide sequences of two Sida-infecting geminiviruses from Honduras were determined. The symptoms of both viruses are identical in Sida rhombifolia but different in Nicotiana benthamiana. An additional symptom of one virus was yellow vein clearing on infected N. benthamiana leaves. Both Sida golden mosaic viruses (SiGMV-Ho and SiGMV-Ho(yv)) have bipartite genomes (DNAs A and B). From the SiGMV-Ho(yv)-infected S. rhombifolia plant two different DNA B molecules were isolated and cloned. They differ in length by 24 nucleotides [SiGMV-Ho(yv) B1 (2593 nt) and B2 (2569 nt)] and at eight nucleotide positions. Both proteins encoded by DNA B (BV1 and BC1) are affected by these substitutions. Computer analysis shows that the bipartite genomes resemble those of other whitefly-transmitted geminiviruses. From homology analyses we conclude that both viruses are closely related but distinct. Comparison with a Sida-infecting virus from Costa Rica (SiGMV-Co) showed that the two viruses from Honduras are more similar to each other than either of them are to SiGMV-Co. Exchange of SiGMV-Ho and SiGMV-Ho(yv) genomic components resulted in viable pseudorecombinant viruses. SiGMV-Ho DNA A was able to produce a viable pseudorecombinant with SiGMV-Co DNA B while the reciprocal exchange was not infectious in N. benthamiana. SiGMV-Ho(yv) DNA A and SiGMV-Co DNA B produced a viable pseudorecombinant virus whereas only pseudorecombination of SiGMV-Co DNA A with SiGMV-Ho(yv) DNA B2, and not with DNA B1, was infectious in N. benthamiana.

Inhibition of nucleoside diphosphate kinase activity by in vitro phosphorylation by protein kinase CK2. Differential phosphorylation of NDP kinases in HeLa cells in culture.

Although a number of nucleoside diphosphate kinases (NDPKs) have been reported to act as inhibitors of metastasis or as a transcription factor in mammals, it is not known whether these functions are linked to their enzymatic activity or how this protein is regulated. In this report, we show that in vitro protein kinase CK2 catalyzed phosphorylation of human NDPK A inhibits its enzymatic activity by inhibiting the first step of its ping-pong mechanism of catalysis: its autophosphorylation. Upon in vivo 32P labeling of HeLa cells, we observed that both human NDPKs, A and B, were autophosphorylated on histidine residues, however, only the B isoform appeared to be serine phosphorylated.

Discrimination between acid and alkali-labile phosphorylated residues on Immobilon: phosphorylation studies of nucleoside diphosphate kinase.

We have critically analyzed current methodologies for distinguishing histidine and serine phosphorylated residues in proteins and report a simple technique that assures a reliable discrimination. Electro-transfer of a phosphorylated enzyme to Immobilon membranes and its treatment at pH 1 and 14 in buffers containing 5% methanol allows unambiguous distinction between serine/threonine and histidine phosphorylation (O-phosphomonoesters and phosphoramide, respectively) since under these conditions only one type of residue is dephosphorylated. The addition of 5% methanol to all buffers was indispensable to deplete phosphate from membranes incubated successively under acid and basic conditions. The technique was applied to the study of nucleoside diphosphate kinase (NDP kinase) phosphorylation. In this enzyme, autophosphorylation of active site histidine is an accepted intermediate step in the catalytic phosphate transfer activity of nucleoside diphosphate kinase (NDP kinase). Nonetheless, a significant degree of autophosphorylation on other residues has been reported by several laboratories, and the hypothesis has been advanced that this nonhistidine phosphorylation may play an important role in NDP kinase cellular function, signaling the suppression of metastasis in the case of human NDP kinase A. Using this improved method, we show that human, Escherichia coli and Candida albicans NDP kinases are only autophosphorylated on histidine residues. In addition, we present evidence that the presence of phosphoserine after strong acid hydrolysis of the histidine autophosphorylated enzyme is in fact a nonenzymatic transphosphorylation from phosphohistidine due to the harsh acid treatment. This methodology was also applied to in vivo phosphorylation studies of C. albicans NDP kinase. We believe that the technique will be generally useful in histidine phosphorylation screenings.