Teixeiria lusitanica, a new fossil flower from the Early Cretaceous of Portugal with affinities to Ranunculales

A charcoalified fossil flower bud of a new genus and species (Teixeiria lusitanica) is described from the Early Cretaceous of Portugal. The flower is actinomorphic and unisexually male. At the base of the bud there are several bracts of different sizes, which are followed by sepal-like and petal-like tepals. Bracts and perianth organs seem to be arranged spirally and to exhibit transitions between different organ categories. The androecium has numerous stamens in two sizes, but with unclear arrangement. Pollen is small and tricolpate with a perforate tectum and a densely columellate infratectal layer. No carpels or remains of carpels could be observed on the floral axis. Teixeiria lusitanica shows most affinities to members of Ranunculales. There are also some similarities with Berberidopsis (Berberidopsidaceae, Berberidopsidales) and members of the Saxifragales (Hamamelidaceae and Daphniphyllaceae).     

Effects of glucose, tetrapyrroles and protein kinase C activators on cell proliferation in cultures of Saccharomyces cerevisiae

Abstract Saccharomyces cerevisiae was inoculated into a yeast nitrogen base with either glycerol or glucose as carbon source. Cell proliferation was followed by colony counts on agar medium. Cells in the glycerol-supplemented medium divided less than once in 10 days. When glucose, 6-deoxy-glucose or protoporphyrin IX was added, the cells had doubling times of about 24 h and increased in number to about 0.5 × 10⁶ cells ml⁻¹ Addition of either of the protein kinase C activators oleoyl-acetylglycerol or phorbol-12-myristate-13-acetate did not activate cell proliferation in the glycerol medium. However, when (i) glucose was combined with either protoporphyrin IX or chlorophyllin, or (ii) either protoporphyrin IX or chlorophyllin was combined with either of the protein kinase C activators, the cells had doubling times of about 12 h. Hence, (i) glucose can act as both a carbon source and a signalling molecule for proliferation, and (ii) two systems are involved in activating cell proliferation in S. cerevisiae : one operating through a protein kinase C system and another through a guanylate cyclase system.     

Stable Associations Masked by Temporal Variability in the Marine Copepod Microbiome

Copepod-bacteria interactions include permanent and transient epi- and endobiotic associations that may play roles in copepod health, transfer of elements in the food web, and biogeochemical cycling. Microbiomes of three temperate copepod species (Acartia longiremis, Centropages hamatus, and Calanus finmarchicus) from the Gulf of Maine were investigated during the early summer season using high throughput amplicon sequencing. The most prominent stable component of the microbiome included several taxa within Gammaproteobacteria, with Pseudoalteromonas spp. especially abundant across copepod species. These Gammaproteobacteria appear to be promoted by the copepod association, likely benefitting from nutrient enriched microenvironments on copepods, and forming a more important part of the copepod-associated community than Vibrio spp. during the cold-water season in this temperate system. Taxon-specific associations included an elevated relative abundance of Piscirickettsiaceae and Colwelliaceae on Calanus, and Marinomonas sp. in Centropages. The communities in full and voided gut copepods had distinct characteristics, thus the presence of a food-associated microbiome was evident, including higher abundance of Rhodobacteraceae and chloroplast sequences in the transient communities. The observed variability was partially explained by collection date that may be linked to factors such as variable time since molting, gender differences, and changes in food availability and type over the study period. While some taxon-specific and stable associations were identified, temporal changes in environmental conditions, including food type, appear to be key in controlling the composition of bacterial communities associated with copepods in this temperate coastal system during the early summer.     

Phospholipid composition of plasma and erythrocytes in the neonate

The total phospholipids and their various classes in erythrocytes and blood plasma were determined quantitatively by means of two-dimensional thin-layer chromatography. The total amount of phospholipids in neonate plasma was approximately half of that found in adult plasma, however, the amount of phospholipids in erythrocytes of the neonate was significantly higher. The differences were observed in some classes of phospholipids in the plasma and erythrocytes of neonates as well as adult human beings.     

Regulation of type VI collagen synthesis in transformed mesenchymal cells.

We have analysed the effects of oncogenic transformation on the expression of type VI collagen in mesenchymal cells. Synthesis of type VI collagen was almost completely inhibited in fibroblasts transformed by DNA or RNA tumour viruses or in cells derived from spontaneous mesenchymal tumours. Inhibition of type VI collagen synthesis appears, therefore, to be a common phenomenon of transformed mesenchymal cells. When introduced into normal cells by viral vectors, the 'nuclear' oncogene v-myc had an inhibitory effect similar to that of the 'cytoplasmic' oncogene v-src. Fibroblasts infected with a temperature-sensitive strain of Rous sarcoma virus (NY68) produced type VI collagen at the restrictive, but not at the permissive temperature. If such cells were shifted from the permissive to the restrictive temperature, synthesis of the individual subunits of type VI collagen was co-ordinately induced. These results demonstrate that the activity of a single oncogene product is sufficient to inhibit type VI collagen expression.