Conditional association between melanism and personality in Israeli Barn Owls

Capsule Boldness defines the extent to which animals are willing to take risks in the presence of a predator. Late, but not early, in the breeding season, Israeli nestling Barn Owls displaying larger black feather spots were more docile, feigned death longer and had a lower breathing rate when handled than smaller-spotted nestlings. Larger-spotted breeding females were less docile if heavy but more more docile if light. The covariation between personality (boldness vs. timid) and melanin-based colouration is therefore conditional on environmental factors.     

Remote sensing of chlorophyll in Lake Kinneret using highspectral-resolution radiometer and Landsat TM: spectral features of reflectance and algorithm development

High-resolution reflectance spectra in the range of 400–850nm were obtained from Lake Kinneret during a period when densepopulations of the dinoflagellate Peridinium gatunense dominatedthe phytoplankton. Chlorophyll (Chl) concentrations ranged from5.1 to 185 mg m^–3 and from 2.4 to 187.5 mg m^–3 inthe samples of two independent experiments. The most prominentfeatures of the reflectance spectra were: (i) a wide minimumfrom 400 to 500 nm; (ii) a maximum at 550–570 nm, whichdid not surpass 3% in samples with high Chl concentration (>20mgm^–3), indicating a strong absorption by pigments in thegreen range of the spectrum; (iii) a minimum at 676 nm; thiswas {small tilde}1% and was almost insensitive to variationin Chl concentration >10 mg m^–3; (iv) a maximum reflectanceshowed near 700 nm; its magnitude and position were highly dependenton chlorophyll concentration. High-spectral-resolution datawere used as a guideline for selection of the most suitablespectral bands for chlorophyll remote sensing. Models were devised,based on the calculation of the integrated area above the baselinefrom 670 to 850 nm and the reflectance maximal height withinthis range. Some algorithms already used m previous studieswere tested and showed a plausible degree of accuracy when appliedto the current data base. However, novel models devised in thisstudy improved substantially the accuracy of Chl estimationby remotely sensed data, by reducing the estimation error from>11 to 6.5 mg m^–3 Those models were validated by anindependent data set where Chl concentration ranged over twoorders of magnitude. The use of three relatively narrow spectralbands was sufficient for Chl mapping in Lake Kinneret. Therefore,a relatively simple sensor, measuring only a few bands willbe employed in future applications for Chl monitoring in inlandwaters. Radiometric data were also used to simulate radiancesin the channels of TM Landsat and to find the algorithm forChl assessment. The ratio of channel 4 to channel 3 was usedand enabled Chl estimation with an error of <15mg m^–3This algorithm was employed to map Chl in the entire area ofLake Kinneret with 10 gradations.     

N-type Calcium Channel in the Pathogenesis of Experimental Autoimmune Encephalomyelitis

One of the family of voltage-gated calcium channels (VGCC), the N-type Ca²⁺ channel, is located predominantly in neurons and is associated with a variety of neuronal responses, including neurodegeneration. A precise mechanism for how the N-type Ca²⁺ channel plays a role in neurodegenerative disease, however, is unknown. In this study, we immunized N-type Ca²⁺ channel α_1B-deficient (α_1B^−/−) mice and their wild type (WT) littermates with myelin oligodendrocyte glycoprotein 35–55 and analyzed the progression of experimental autoimmune encephalomyelitis (EAE). The neurological symptoms of EAE in the α_1B^−/− mice were less severe than in the WT mice. In conjunction with these results, sections of the spinal cord (SC) from α_1B^−/− mice revealed a reduction in both leukocytic infiltration and demyelination compared with WT mice. No differences were observed in the delayed-type hypersensitivity response, spleen cell proliferation, or cytokine production from splenocytes between the two genotypes. On the other hand, Western blot array analysis and RT-PCR revealed that a typical increase in the expression of MCP-1 in the SC showed a good correlation with the infiltration of leukocytes into the SC. Likewise, immunohistochemical analysis showed that the predominant source of MCP-1 was activated microglia. The cytokine-induced production of MCP-1 in primary cultured microglia from WT mice was significantly higher than that from α_1B^−/− mice and was significantly inhibited by a selective N-type Ca²⁺ channel antagonist, ω-conotoxin GVIA or a withdrawal of extracellular Ca²⁺. These results suggest that the N-type Ca²⁺ channel is involved in the pathogenesis of EAE at least in part by regulating MCP-1 production by microglia.     

Cell lineage analysis of the mammalian female germline

Fundamental aspects of embryonic and post-natal development, including maintenance of the mammalian female germline, are largely unknown. Here we employ a retrospective, phylogenetic-based method for reconstructing cell lineage trees utilizing somatic mutations accumulated in microsatellites, to study female germline dynamics in mice. Reconstructed cell lineage trees can be used to estimate lineage relationships between different cell types, as well as cell depth (number of cell divisions since the zygote). We show that, in the reconstructed mouse cell lineage trees, oocytes form clusters that are separate from hematopoietic and mesenchymal stem cells, both in young and old mice, indicating that these populations belong to distinct lineages. Furthermore, while cumulus cells sampled from different ovarian follicles are distinctly clustered on the reconstructed trees, oocytes from the left and right ovaries are not, suggesting a mixing of their progenitor pools. We also observed an increase in oocyte depth with mouse age, which can be explained either by depth-guided selection of oocytes for ovulation or by post-natal renewal. Overall, our study sheds light on substantial novel aspects of female germline preservation and development.     

Proteins and DNA elements essential for the CRISPR adaptation process in Escherichia coli

The clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR/Cas) constitute a recently identified prokaryotic defense mechanism against invading nucleic acids. Activity of the CRISPR/Cas system comprises of three steps: (i) insertion of alien DNA sequences into the CRISPR array to prevent future attacks, in a process called 'adaptation', (ii) expression of the relevant proteins, as well as expression and processing of the array, followed by (iii) RNA-mediated interference with the alien nucleic acid. Here we describe a robust assay in Escherichia coli to explore the hitherto least-studied process, adaptation. We identify essential genes and DNA elements in the leader sequence and in the array which are essential for the adaptation step. We also provide mechanistic insights on the insertion of the repeat-spacer unit by showing that the first repeat serves as the template for the newly inserted repeat. Taken together, our results elucidate fundamental steps in the adaptation process of the CRISPR/Cas system.     

Phylogenetic,Metabolic, and Taxonomic Diversities Shape Mediterranean Fruit Fly Microbiotas during Ontogeny

The Mediterranean fruit fly (medfly) (Ceratitis capitata) lays eggs in fruits, where larvae subsequently develop, causing large-scale agricultural damage. Within its digestive tract, the fly supports an extended bacterial community that is composed of multiple strains of a variety of enterobacterial species. Most of these bacteria appear to be functionally redundant, with most strains sustaining diazotrophy and/or pectinolysis. At least some of these bacteria were shown to be vertically inherited, but colonization, structural, and metabolic aspects of the community''s dynamics have not been investigated. We used fluorescent in situ hybridization, metabolic profiling, plate cultures, and pyrosequencing to show that an initial, egg-borne, diverse community expands throughout the fly''s life cycle. While keeping “core” diazotrophic and pectinolytic functions, it also harbors diverse and fluctuating populations that express varied metabolic capabilities. We suggest that the metabolic and compositional plasticity of the fly''s microbiota provides potential adaptive advantages to the medfly host and that its acquisition and dynamics are affected by mixed processes that include stochastic effects, host behavior, and molecular barriers.     

Mutant p53 Attenuates the Anti-Tumorigenic Activity of Fibroblasts-Secreted Interferon Beta

Mutations in the p53 tumor suppressor protein are highly frequent in tumors and often endow cells with tumorigenic capacities. We sought to examine a possible role for mutant p53 in the cross-talk between cancer cells and their surrounding stroma, which is a crucial factor affecting tumor outcome. Here we present a novel model which enables individual monitoring of the response of cancer cells and stromal cells (fibroblasts) to co-culturing. We found that fibroblasts elicit the interferon beta (IFNβ) pathway when in contact with cancer cells, thereby inhibiting their migration. Mutant p53 in the tumor was able to alleviate this response via SOCS1 mediated inhibition of STAT1 phosphorylation. IFNβ on the other hand, reduced mutant p53 RNA levels by restricting its RNA stabilizer, WIG1. These data underscore mutant p53 oncogenic properties in the context of the tumor microenvironment and suggest that mutant p53 positive cancer patients might benefit from IFNβ treatment.     

Design, synthesis and characterization of podocarpate derivatives as openers of BK channels

We found that the podocarpic acid structure provides a new scaffold for chemical modulators of large-conductance calcium-activated K(+) channels (BK channels). Structure-activity analysis indicates the importance of both the arrangement (i.e., location and orientation) of the carboxylic acid functionality of ring A and the hydrophobic region of ring C for expression of BK channel-opening activity.     

Purification and physicochemical and immunological analysis of chicken alpha-fetoprotein

Chicken alpha-fetoprotein was isolated from 12 to 13-day-old embryonic chicken serum by column chromatography on CM-Sephadex C-50. Hydroxyapatite and DEAE-Sephadex A-25. The purified protein was homogeneous based on polyacrylamide gel electrophoresis, immunoelectrophoresis and isoelectric focusing. The purified protein had the following physicochemical and immunological properties. (1) It was a glycoprotein with a single polypeptide chain. (2) The molecular weight of the protein was estimated at 71,000 by SDS-polyacrylamide gel electrophoresis. (3) The isoelectric point of the protein was 4.90. (4) The amino acid composition of the protein was similar to those of mammalian alpha-fetoproteins. (5) The protein showed no steroid-binding capacity. (6) It was immunologically distinct from mammalian alpha-fetoprotein. (7) No immunological cross-reaction was observed between the protein and chicken albumin.