Revision of the plant geographical territories of Israel and Sinai

The phytogeographical territories of Israel and Sinai are revised using a large mass of species distribution data. With the help of chorotype frequencies for 25 km² individual squares in Israel, territories were defined on the basis of the first two most frequent chorotypes. The similarity of boundaries in the resulting phytogeographical map with a physiognomic map suggests that the latter may be used in preliminary stages of the preparation of plant geographical maps.     

Meiotic behavior of an unequal bivalent in the grasshopper Calliptamus palaestinensis Bdhr.

Summary Unequal bivalents were found in two of four populations of the short horned grasshopper, Calliptamus palaestinensis bdhr. sampled in Israel.The inequality of the homologues was due to an extra segment which was heterochromatic and apparently terminal. Pairing configurations at pachytene and position of chiasmata at later stages revealed however that the extra segment was interstitial, and the long member terminated in a minute segment homologous to the terminal part of its normal partner. The percentage of reductional divisions at anaphase I corresponded well with the percentage of terminal chiasmata (i.e. distal to the extra segment) observed at diakinesis.The assumption of an interstitial position of the extra segment would explain the previously puzzling examples of unequal bivalents in Orthoptera whose reductional divisions have not been readily accounted for otherwise.     

Comparison of cytoplasmic superoxide dismutase in liver,heart and brain of aging rats and mice

Comparisons of the specific activity of cytoplasmic superoxide dismutase, in homogenates of liver, brain and heart demonstrate considerably reduced activity in livers of aging rats and mice, a very small reduction in specific activity in the heart and no reduction in the brain of aging animals.Antisera elicited in rabbits against purified superoxide dismutase from liver of either young or old rats revealed complete cross-reactivity with the heart and brain enzymes. They also exhibited complete cross-reactivity with the mouse enzymes from all three organs. This finding has, for the first time, enabled a comparison of possible age-dependent alterations in the same enzyme antigen in different cell types.Despite the differences in age-related changes in specific activity in homogenates of liver, heart and brain the enzyme shows a considerable decline in catalytic activity per antigenic unit in $\text{all}$ three organs in both aging rats and mice.     

Ethnic groups and high sensitivity C-reactive protein in Israel

Abstract

High-sensitivity C-reactive protein (hs-CRP) is a biomarker that correlates with atherothrombotic risk and outcome. hs-CRP is influenced by various modifiable and non-modifiable factors. We studied the relationship between ethnic background and hs-CRP level, among the Jewish population in Israel. A total of 3659 men and 2180 women were divided into two ethnic groups (Ashkenazi and Sephardic Jews), based on the knowledge of Jewish immigration patterns throughout the centuries. Mean hs-CRP levels were calculated for each group and were adjusted for various factors known to influence hs-CRP. Sephardic Jews were found to have higher adjusted mean hs-CRP levels (2.0 mg l^?1 for men and 3.9 mg l^?1 for women) compared with Ashkenazi Jews (1.5 mg l^?1 for men and 2.9 mg l^?1 for women). Ethnic background emerged as an independent significant predictor of hs-CRP levels. We demonstrated that ethnicity is an important factor when considering hs-CRP as a marker of atherothrombotic risk.     

Dendritic cell function can be modulated through cooperative actions of TLR ligands and invariant NKT cells

The quality of signals received by dendritic cells (DC) in response to pathogens influences the nature of the adaptive response. We show that pathogen-derived signals to DC mediated via TLRs can be modulated by activated invariant NKT (iNKT) cells. DC maturation induced in vivo with any one of a variety of TLR ligands was greatly improved through simultaneous administration of the iNKT cell ligand alpha-galactosylceramide. DC isolated from animals treated simultaneously with TLR and iNKT cell ligands were potent stimulators of naive T cells in vitro compared with DC from animals treated with the ligands individually. Injection of protein Ags with both stimuli resulted in significantly improved T cell and Ab responses to coadministered protein Ags over TLR stimulation alone. Ag-specific CD8(+) T cell responses induced in the presence of the TLR4 ligand monophosphoryl lipid A and alpha-galactosylceramide showed faster proliferation kinetics, and increased effector function, than those induced with either ligand alone. Human DC exposed to TLR ligands and activated iNKT cells in vitro had enhanced expression of maturation markers, suggesting that a cooperative action of TLR ligands and iNKT cells on DC function is a generalizable phenomenon across species. These studies highlight the potential for manipulating the interactions between TLR ligands and iNKT cell activation in the design of effective vaccine adjuvants.     

The dynamic of the t-haplotype in wild populations of the house mouse Mus musculus domesticus in Israel

The t-haplotype, a variant of the proximal part of the mouse chromosome 17, is composed of at least four inversions and is inherited as a single genetic unit. The haplotype causes embryonic mortality or male sterility when homozygous. Genes within the complex are responsible for distortion of Mendelian transmission ratio in males. Thus, the t-haplotype in heterozygous males is transferred to over 95% of the progeny. We examined the dynamic and behavior of the t-haplotype in wild populations of the house mouse in Israel. The Israeli populations show high frequency (15%–20%) of both partial and complete t-carrying mice, supporting the suggestion that the t-complex evolved in the M. domesticus line in the Israeli region. In one population that had the highest frequency of t-carrying individuals, we compared the level of gene diversity between t-carrying and normal mice in the marker’s loci: H-2 locus of the major histocompatibility complex (MHC) on the t-haplotype of chromosome 17, three microsatellites on other chromosomes, and the mitochondrial D-loop. Genetic variability was high in all tested loci in both t and (+) mice. All t mice carried the same chromosome and showed the same H-2 haplotype. While t-carrying mice showed significant H-2 heterozygotes access, (+) mice expressed significant H-2 heterozygote deficiency. There were no differences in the level of gene diversity between t and (+) mice in the other loci. Heterozygosity level at the MHC may be an additional factor in the selective forces balancing the t-haplotype polymorphism.     

Individual-learning ability predicts social-foraging strategy in house sparrows

Social foragers can use either a ‘producer’ strategy, which involves searching for food, or a ‘scrounger’ strategy, which involves joining others'' food discoveries. While producers rely on personal information and past experience, we may ask whether the tendency to forage as a producer is related to being a better learner. To answer this question, we hand-raised house sparrow (Passer domesticus) nestlings that upon independence were given an individual-learning task that required them to associate colour signal and food presence. Following the testing phase, all fledglings were released into a shared aviary, and their social-foraging tendencies were measured. We found a significant positive correlation between individual''s performance in the individual-learning task and subsequent tendency to use searching (producing) behaviour. Individual-learning score was negatively correlated with initial fear of the test apparatus and with body weight. However, the correlation between individual learning and searching remained significant after controlling for these variables. Since it was measured before the birds entered a social group, individual-learning ability could not be the outcome of being a producer. However, the two traits may be initially associated, or individual learning could facilitate producing behaviour. To our knowledge, this is the first evidence that associates individual-learning abilities with social-foraging strategies in animal groups.     

Immunization with a lentivector that targets tumor antigen expression to dendritic cells induces potent CD8+ and CD4+ T-cell responses

Lentivectors stimulate potent immune responses to antigen transgenes and are being developed as novel genetic vaccines. To improve safety while retaining efficacy, we constructed a lentivector in which transgene expression was restricted to antigen-presenting cells using the mouse dectin-2 gene promoter. This lentivector expressed a green fluorescent protein (GFP) transgene in mouse bone marrow-derived dendritic cell cultures and in human skin-derived Langerhans and dermal dendritic cells. In mice GFP expression was detected in splenic dectin-2⁺ cells after intravenous injection and in CD11c⁺ dendritic cells in the draining lymph node after subcutaneous injection. A dectin-2 lentivector encoding the human melanoma antigen NY-ESO-1 primed an NY-ESO-1-specific CD8⁺ T-cell response in HLA-A2 transgenic mice and stimulated a CD4⁺ T-cell response to a newly identified NY-ESO-1 epitope presented by H2 I-A^b. As immunization with the optimal dose of the dectin-2 lentivector was similar to that stimulated by a lentivector containing a strong constitutive viral promoter, targeting antigen expression to dendritic cells can provide a safe and effective vaccine.     

Pattern of settlement and natural chimerism in the colonial urochordate Botryllus schlosseri

Colonies of the cosmopolitan urochordate Botryllus schlosseri that share one or both alleles at a single allorecognition locus (Fu/HC) and come into tissue contacts, may fuse and form a mixed entity, a chimera. Botryllus populations worldwide exhibit unprecedented extensive polymorphism at this locus, a result that restricts fusions to kin encounters. This study aims to compare spatiotemporal configurations in source and introduced B. schlosseri populations, residing on natural and man-made substrata, respectively. By using four microsatellite loci, we tested genetic consanguinity of colonies settled naturally along spatial vectors on both, natural (native populations) and man-made (introduced) substrates. Four populations were studied. Results revealed that B. schlosseri colonies, on both substrate types, assemble in groups of relatives that share similar microsatellite profiles. We suggest that this pattern of settlement promotes the formation of chimeras, which evoke conflicting interactions: cooperation between different somatic cell lines that constitute the colonial soma and competition between germ cells that inhabit the chimera gonads. Under natural conditions, the chimera may allow genetic flexibility that depends on joint genomic fitness of its partners. This is probably one of the life history characteristics that led to the worldwide distribution success of this species.