Karyological studies in Sonchus section Muritimi (Asteraceae) from the Iberian Peninsula

MEJÍAS, J. A. & VALDÉS, B., 1988. Karyologiepl studies in Sonchus section Madtimi (Asteraceae) from the Iberian Peninmula. Karyological data support the distinction of S. aquatilis Pourret and S. maritimus L. at the specific level. Karyological data and hybridization experiments support the idea that S. × novocaslcllanus Cirujano has been produced by the hybridization of S. crassifolius Pourret ex Willd. and S. maritimus L.     

TH2 cytokines modulate the IL-9R expression on human neutrophils

Interleukin (IL)-9 is associated with key pathological features of asthma such as airway hyperresponsiveness, bronchoconstriction and mucus production. Inflammatory responses mediated by IL-9 rely on the expression of the IL-9R which has been reported on lung epithelial cells, T lymphocytes and recently on airway granulocyte infiltrates. In this study, we assessed the regulatory and constitutive cell surface expression of the IL-9Rα in unfractionated and purified human neutrophils from atopic asthmatics, atopic non-asthmatics and healthy normal controls. We demonstrate that T_H2 cytokines (IL-4 or IL-13) and granulocyte macrophage-colony stimulating factor (GM-CSF) up-regulated mRNA and cell surface expression levels of the IL-9Rα in primary human and HL-60 differentiated neutrophils. Pharmacological inhibition of NF-κB did not affect T_H2-mediated IL-9Rα expression in human neutrophils although IFN-γ and IL-10 down-regulated IL-9Rα expression when co-incubated with IL-4, IL-13 or GM-CSF. Collectively, our results reveal a regulatory function for IFN-γ and IL-10 on modulating the inducible IL-9Rα expression levels on peripheral blood neutrophils by T_H2 cytokines.     

Targeting HER2: A report on the in vitro and in vivo pre-clinical data supporting trastuzumab as a radioimmunoconjugate for clinical trials

The potential of the HER2-targeting antibody trastuzumab as a radioimmunoconjugate useful for both imaging and therapy was investigated. Conjugation of trastuzumab with the acyclic bifunctional chelator CHX-A″-DTPA yielded a chelate:protein ratio of 3.4 ± 0.3; the immunoreactivity of the antibody unaffected. Radiolabeling was efficient, routinely yielding a product with high specific activity. Tumor targeting was evaluated in mice bearing subcutaneous (s.c.) xenografts of colorectal, pancreatic, ovarian and prostate carcinomas. High uptake of the radioimmunoconjugate, injected intravenously (i.v.), was observed in each of the models and the highest tumor %ID/g (51.18 ± 13.58) was obtained with the ovarian (SKOV-3) tumor xenograft. Specificity was demonstrated by the absence of uptake of ¹¹¹In-trastuzumab by melanoma (A375) s.c. xenografts and ¹¹¹In-HuIgG by s.c. LS-174T xenografts. Minimal uptake of i.v. injected ¹¹¹In-trastuzumab in normal organs was confirmed in non-tumor-bearing mice. The in vivo behavior of ¹¹¹In-trastuzumab in mice bearing intraperitoneal (i.p.) LS-174T tumors resulted in a tumor %ID/g of 130.85 ± 273.34 at 24 h. Visualization of tumor, s.c. and i.p. xenografts was achieved by γ-scintigraphy and PET imaging. Blood pool was evident as expected but cleared over time. The blood pharmacokinetics of i.v. and i.p. injected ¹¹¹In-trastuzumab was determined in mice with and without tumors. The data from these in vitro and in vivo studies supported advancement of radiolabeled trastuzumab into two clinical studies, a Phase 0 imaging study in the Molecular Imaging Program of the National Cancer Institute and a Phase 1 radioimmunotherapy study at the University of Alabama.Key words: monoclonal antibody, HER2, trastuzumab, radioimmunodiagnosis, radioimmunotherapy     

A high level interface to SCOP and ASTRAL implemented in Python

Background  

Benchmarking algorithms in structural bioinformatics often involves the construction of datasets of proteins with given sequence and structural properties. The SCOP database is a manually curated structural classification which groups together proteins on the basis of structural similarity. The ASTRAL compendium provides non redundant subsets of SCOP domains on the basis of sequence similarity such that no two domains in a given subset share more than a defined degree of sequence similarity. Taken together these two resources provide a 'ground truth' for assessing structural bioinformatics algorithms. We present a small and easy to use API written in python to enable construction of datasets from these resources.     

Phosphorus supply drives rapid turnover of membrane phospholipids in the diatom Thalassiosira pseudonana

In low-phosphorus (P) marine systems, phytoplankton replace membrane phospholipids with non-phosphorus lipids, but it is not known how rapidly this substitution occurs. Here, when cells of the model diatom Thalassiosira pseudonana were transferred from P-replete medium to P-free medium, the phospholipid content of the cells rapidly declined within 48 h from 45±0.9 to 21±4.5% of the total membrane lipids; the difference was made up by non-phosphorus lipids. Conversely, when P-limited T. pseudonana were resupplied with P, cells reduced the percentage of their total membrane lipids contributed by a non-phosphorus lipid from 43±1.5 to 7.3±0.9% within 24 h, whereas the contribution by phospholipids rose from 2.2±0.1 to 44±3%. This dynamic phospholipid reservoir contained sufficient P to synthesize multiple haploid genomes, suggesting that phospholipid turnover could be an important P source for cells. Field observations of phytoplankton lipid content may thus reflect short-term changes in P supply and cellular physiology, rather than simply long-term adjustment to the environment.     

Seed germination temperatures of eight Mexican Agave species with economic importance

The genetic diversity of Agave plants is threatened by clonal commercial reproduction and climatic change. Sexual reproduction is uncommon and research on seed germination is scarce. The present study evaluated the seed germination of Agave lechuguilla, Agave striata, Agave americana var. marginata, Agave asperrima, Agave cupreata, Agave duranguesis, Agave angustifolia ssp. tequilana and Agave salmiana at constant temperatures (10, 15, 20, 25, 30, 35 and 40°C). Initial imbibition (after the first 12 h) was significantly variable among species, positively correlated with seed weight (r = 0.6560, P < 0.001) and increased with temperature (from 35% at 10°C to 66% at 40°C). Temperature affected maximum imbibition (83–150%) for A. asperrima, A. lechuguilla, A. salmiana and A. striata; other species averaged 110%. Most germination kinetics best fitted a logistic model, whereas only a few treatments fit a Weibull model. The time to germination onset diminished (P < 0.05) from 125–173 h at 15°C to 68–84 h at 25°C, and then ascended to 84–196 h at 35°C. The mean germination rate and seed germination percentage after 312 h peaked at 25°C (0.50–0.95% seeds/h and 85–99%, respectively) and fell (P < 0.05) to near zero at 10 and 40°C. Temperatures of 10, 35 and 40°C were partially lethal to A. asperrima, A. duranguensis and A. salmiana seeds. The time to germination onset, seed germination percentage after 312 h and mean germination rate are best described by a Gaussian distribution, with its optimum at approximately 25°C. Thus, optimum temperatures are related to the ecological characteristics of each species area.