Accessory cell stimulation of T cell proliferation requires active antigen processing, Ia-restricted antigen presentation, and a separate nonspecific 2nd signal

The roles of Ia+ accessory cells in H-2-restricted stimulation of antigen-specific T cell proliferation were explored in an in vitro model. L-glutamic acid60-L-alanine30-L-tyrosine10-(GAT) primed BALB/c nylon wool-passed T cells were depleted of Ia+ antigen-presenting cells (APC) by treatment with monoclonal anti-Ia antibody plus complement. Such cells failed to respond to soluble GAT, or to soluble GAT in the presence of phorbol myristic acetate (PMA), which is known to stimulate production of, or replace, IL-1 in vitro. Addition of gamma-irradiated syngeneic spleen cells reconstituted the response to soluble GAT, but addition of ultraviolet (UV) light-irradiated spleen cells did not, even in the presence of PMA. Preincubation of cells with GAT for 24 hr, followed by washing, then gamma irradiation, generated a cell population able to stimulate GAT-primed T cells to proliferate. The same pulsed cells exposed to UV irradiation failed to stimulate T cell responses unless PMA was added to the cultures. The relevant cells in this UV-irradiated population are Ia+. It is concluded that a finite period of time for interaction of metabolically intact APC with antigen is required before creation of an appropriate (Ia + antigen) signal recognized by the T cell. In addition to such Ia-restricted antigen presentation, however, a 2nd nonspecific signal, again requiring metabolically active APC for elaboration, is necessary for detectable T cell activation. These studies thus define 3 separable activities of APC during the process of H-2 restricted T cell activation.     

Humirianthenolides,new degraded diterpenoids from Humirianthera rupestris

The tuber of Humirianthera rupestris (Icacinaceae) contains the degraded diterpenoids 3β,20-epoxy-30α- hydroxy- 14-oxo-9β-podocarpan-19,6β-olide (humirianthenolide A), 3β,20-epoxy-3α,14α-dihydroxy-9β-podocarpan-19,6β- olide (humirianthenolide B), 3β,20; 16,14-diepoxy-3α-hydroxy-17-nor-15-oxo-9β-abiet-13-en-19,6β-olide (humirianthenolide C), 3β,20-epoxy-3α,14-dihydroxy-13-oxo-9β-podocarp-8(14)-en-19,6β-olide (humirianthenolide D), 3β,20-epoxy-3α-hidroxy-14-oxo-8α,9β-podocarpan-19,6β-olide (humirianthenolide E) and 3β,20-epoxy-3α,14β- dihydroxy-8α,9β-podocarpan-19,6β-olide (humirianthenolide F). ¹H NMR and ¹³C NMR spectroscopy were efrective for the determination of the humirianthenolide structures.     

The use of azidoarylimidoesters in RNA-protein cross-linking studies with Escherichia coli ribosomes

A series of related hetero-bifunctional RNA-protein cross-linking reagents has been prepared, carrying an imidoester or N-hydroxysuccinimide ester function at one end of the molecule, and a phenylazido function at the other. These compounds have been applied to RNA-protein cross-linking studies with ribosomal subunits, and one of them, p-azido-phenylacetic imidoester, has proved to be a particularly useful reagent for this purpose. The reagent first reacts specifically with protein amino groups, and subsequent photolysis of the azide group leads to cross-linking to the RNA in yields of up to 8% of the total protein. The whole reaction takes place under very mild conditions in aqueous solution.The individual proteins concerned in the cross-links have been identified by two-dimensional gel electrophoresis, and the existence of a covalent cross-link was confirmed by the isolation by two different methods of protein-oligonucleotide complexes carrying a ³²P label. Although most of the ribosomal proteins could be cross-linked to their corresponding ribosomal RNA within the individual subunits, RNA-protein cross-links at the ribosomal subunit interface were only detectable in vanishingly small amounts.The advantages of this type of genuine hetero-bifunctional reagent in RNA-protein cross-linking studies are discussed.     

Dehydrodieugenols from Ocotea cymbarum

The trunk wood of Ocotea cymbarum from the Amazon basin contains α-phellandrene, α-pinene, eugenol, dehydrodieugenol and its monomethyl ether, as well as the previously unknown dehydrodieugenol-B (4,5′-diallyl-2′-hydroxy-2,3′-dimethoxydiphenyl ether).     

Idiotypic analysis of anti-GAT antibodies. VII. Common idiotype on hybridoma antibodies to poly(Glu60 Ala40)

A single DBA/2 mouse, immunized with L-glutamic acid60-L-alanine40 (GA), was used to produce hybridoma cell lines. Seven hybridoma anti-GA antibodies were obtained for idiotypic analyses. Two hybridoma anti-L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) antibodies, preferentially reactive to GA, were studied in parallel. Anti-idiotypic antisera to purified anti-GAT and anti-GA serum antibodies and to hybridoma anti-GA antibodies were analyzed by idiotype binding and inhibition of idiotype binding assays. Five of the nine hybridoma antibodies exhibited common GA-1 idiotypic specificities previously demonstrated on the majority of anti-GA antibodies of inbred mouse strains of differing immunoglobulin heavy chain linkage groups; these hybridoma antibodies also possessed private idiotypic determinants. Two GA-1 negative hybridoma anti-GA antibodies appeared identical by immunochemical criteria, arguing that somatic hybridization does not artifactually generate private idiotypic determinants. The results demonstrate that the common GA-1 idiotype system is associated with a family of nonidentical but idiotypically related antibody molecules present in a single DBA/2 mouse, and these antibodies are part of the "GA-1 idiotypic family".     

1,3-diaryl-propanes and propan-2-ols from Virola species

The trunk woods of two Amazonian Myristicaceae, Virola minutiflora and V. elongata, contain respectively 1-(2-hydroxy-4-methoxyphenyl)-3-(3,4-m     

Diterpenoids from Micrandropsis scleroxylon

The structure of micrandrol-C from Micrandropsis scleroxylon (Euphorbiaceae) is revised to 2,6-dihydroxy-7-methyl-1-methylthiophenanthrene. This and other micrandrols are probably diterpenes in view of their co-occurrence with micrandrol-D, the hemiketal of 1,2,3,4,9,10-hexahydro-6-hydroxy-4a-hydroxymethyl-1,1,7-trimethy-2-oxophenanthrene.     

Primary Malignant Tumors of the Heart

Because of their rarity, primary malignant tumors of the heart continue to evade clinical preoperative diagnosis. In five cases of malignant heart tumor that were reviewed from the diagnostic point of view, the clinical symptoms and radiographic abnormalities were found to be similar to those produced by more common heart diseases. The diagnosis of malignant cardiac tumor should be considered in a patient with heart disease who has (1) an unusual cardiomediastinal silhouette, (2) an atypical cardiac calcification, and (3) clinical or radiographic cardipulmonary findings which do not conform to the expected behavior of the common forms of heart disease.     

Evolutionary history of the European free-tailed bat,a tropical affinity species spanning across the Mediterranean Basin

The Mediterranean Basin is a global biodiversity hotspot, hosting a number of native species belonging to families that are found almost exclusively in tropical climates. Yet, whether or not these taxa were able to survive in the Mediterranean region during the Quaternary climatic oscillations remains unknown. Focusing on the European free-tailed bat (Tadarida teniotis), we aimed to (a) identify potential ancient populations and glacial refugia; (b) determine the post-glacial colonization routes across the Mediterranean; and (c) evaluate current population structure and demography. Mitochondrial and nuclear markers were used to understand T. teniotis evolutionary and demographic history. We show that T. teniotis is likely restricted to the Western Palearctic, with mitochondrial phylogeny suggesting a split between an Anatolian/Middle East clade and a European clade. Nuclear data pointed to three genetic populations, one of which is an isolated and highly differentiated group in the Canary Islands, another distributed across Iberia, Morocco, and France, and a third stretching from Italy to the east, with admixture following a pattern of isolation by distance. Evolutionary and demographic reconstruction supports a pre-Last Glacial Maximum (LGM) colonization of Italy and the Anatolian/Middle East, while the remaining populations were colonized from Italy after the Younger Dryas. We also found support for demographic expansion following the Iberian colonization. The results show that during the LGM T. teniotis persisted in Mediterranean refugia and has subsequently expanded to its current circum-Mediterranean range. Our findings raise questions regarding the physiological and ecological traits that enabled species with tropical affinities to survive in colder climates.