Allofeeding in Arabian Babblers (Turdoides squamiceps)

Allofeeding is a common social display among adult Arabian babblers (Turdoides squamiceps). The sociology and rates of allofeeding were studied with a tame population of babblers at the Shezaf Nature Reserve in the Rift Valley, Israel. Allofeeding rate varies with the season and food availability. Experimental supplementation to the whole group or to certain individuals greatly increased the rate of allofeeding, but it did not change the social order of the interactions. The interactions were almost always unidirectional: the donor allofed an individual lower in rank. Most of the few exceptions were reciprocal allofeeding among pairs of low-ranking individuals, correlated with a change in dominance between a young male and a young female. Higher-ranking individuals sometimes interfered with allofeedings by lower-ranking ones, and receivers frequently refused to accept the food offered. Allofeeding may therefore be considered as a display of dominance. However, as dominance rank rarely changes, except in very young birds, we suggest that allofeeding interactions display the prestige of the donors, that is, the degree of dominance of one individual over the other.Electronic Supplementary Material Supplementary material is available for this article at .     

α-1-antitrypsin gene delivery reduces inflammation, increases T-regulatory cell population size and prevents islet allograft rejection

Antiinflammatory clinical-grade, plasma-derived human α-1 antitrypsin (hAAT) protects islets from allorejection as well as from autoimmune destruction. hAAT also interferes with disease progression in experimental autoimmune encephalomyelitis (EAE) and in collagen-induced arthritis (CIA) mouse models. hAAT increases IL-1 receptor antagonist expression in human mononuclear cells and T-regulatory (Treg) cell population size in animal models. Clinical-grade hAAT contains plasma impurities, multiple hAAT isoforms and various states of inactive hAAT. We thus wished to establish islet-protective activities and effect on Treg cells of plasmid-derived circulating hAAT in whole animals. Islet function was assessed in mice that received allogeneic islet transplants after mice were given hydrodynamic tail-vein injection with pEF-hAAT, a previously described Epstein-Barr virus (EBV) plasmid construct containing the EBV nuclear antigen 1 (EBNA1) and the family of repeat EBNA1 binding site components (designated "EF") alongside the hAAT gene. Sera collected from hAAT-expressing mice were added to lipopolysaccharide (LPS)-stimulated macrophages to assess macrophage responsiveness. Also, maturation of peritoneal cells from hAAT-expressing mice was evaluated. hAAT-expressing mice accepted islet allografts (n = 11), whereas phosphate-buffered saline-injected animals (n = 11), as well as mice treated with truncated-hAAT-plasmid (n = 6) and untreated animals (n = 20) rapidly rejected islet allografts. In hAAT-expressing animals, local Treg cells were abundant at graft sites, and the IL-1 receptor antagonist was elevated in grafts and circulation. Sera from hAAT-expressing mice, but not control mice, inhibited macrophage responses. Finally, peritoneal cells from hAAT-expressing mice exhibited a semimature phenotype. We conclude that plasmid-derived circulating hAAT protects islet allografts from acute rejection, and human plasma impurities are unrelated to islet protection. Future studies may use this in vivo approach to examine the structure-function characteristics of the protective activities of AAT by manipulation of the hAAT plasmid.     

Stabilization of metapopulation cycles: toward a classification scheme

The stability of population oscillations in ecological systems is considered. Experiments suggest that in many cases the single patch dynamics of predator-prey or host-parasite systems is extinction prone, and stability is achieved only when the spatial structure of the population is expressed via desynchronization between patches. A few mechanisms have been suggested so far to explain the inability of dispersal to synchronize the system. Here we compare a recently discovered mechanism, based on the dependence of the angular velocity on the oscillation amplitude, with other, already known conditions for desynchronization. Using a toy model composed of diffusively coupled oscillators we suggest a classification scheme for stability mechanisms, a scheme that allows for either a priori (based on the system parameters) or a posteriori (based on local measurements) identification of the dominant process that yields desynchronization.     

Isolation and purification of a squamous cell carcinoma of the head and neck-associated antigen identified by autologous antibody

We have previously shown that detection of autologous antibody activity to squamous cell carninoma of the head and neck many be augmented by dissociation in immune complexes. Western blot analysis with autologous antibody has identified a 60 kDa squamous cell carcinoma of the head and neck-associated antigen in spent media and immune complex-dissociated serum ultrafiltrate not recognized by normal human area. Antigen-containing fractions of spent media were eluted from anion exchange columns immediately after serum albumin indicating that the antigen has an acidic PI < 4. Preparative purification of the squamous cell carcinoma antigen was accomplished by anion exchange of concentrated spent media (protein concentration 300 mg/ml) followed by lectin affinity chromotography with a Triticum vulgaris column. A single 60 kDa band was detected by silver stain and Western blot in antigen-containing fractions eluted following lectin affinity chromotography and SDS-PAGE. Final concentration of the antigen was determined to be 1 μm/ml of protein with relative activity increased 1600 × over unfractionated spent media. We conclude that a squamous cell carcinoma of the head and neck-associated antigen, detected by autologous antibody, is an acidic kDa glycoprotein.     

Left Atrial Appendages from Adult Hearts Contain a Reservoir of Diverse Cardiac Progenitor Cells

Aims

There is strong evidence supporting the claim that endogenous cardiac progenitor cells (CPCs) are key players in cardiac regeneration, but the anatomic source and phenotype of the master cardiac progenitors remains uncertain. Our aim was to investigate the different cardiac stem cell populations in the left atrial appendage (LAA) and their fates.

Methods and Results

We investigated the CPC content and profile of adult murine LAAs using immunohistochemistry and flow cytometry. We demonstrate that the LAA contains a large number of CPCs relative to other areas of the heart, representing over 20% of the total cell number. We grew two distinct CPC populations from the LAA by varying the degree of proteolysis. These differed by their histological location, surface marker profiles and growth dynamics. Specifically, CD45^pos cells grew with milder proteolysis, while CD45^neg cells grew mainly with more intense proteolysis. Both cell types could be induced to differentiate into cells with cardiomyocyte markers and organelles, albeit by different protocols. Many CD45^pos cells expressed CD45 initially and rapidly lost its expression while differentiating.

Conclusions

Our results demonstrate that the left atrial appendage plays a role as a reservoir of multiple types of progenitor cells in murine adult hearts. Two different types of CPCs were isolated, differing in their epicardial-myocardial localization. Considering studies demonstrating layer-specific origins of different cardiac progenitor cells, our findings may shed light on possible pathways to study and utilize the diversity of endogenous progenitor cells in the adult heart.     

Changes in sialyltransferase activity during murine T cell differentiation

The main aim of our study was to investigate whether the marked decrease in the expression of peanut agglutinin (PNA) receptors during T-cell maturation in the mouse is accompanied by increased activity of sialyltransferase. By differential agglutination with PNA, mature thymocytes (PNA-) were separated from immature ones (PNA+) and the separated fractions were tested for their sialyltransferase activity with asialofetuin as acceptor. In parallel, sialyltransferase activities of hydrocortisone-resistant thymocytes and untreated thymocytes were also compared. Optimization of the enzyme assay revealed that previous results in the literature were obtained under suboptimal conditions. Using manganese chloride instead of magnesium chloride, we have now found that hydrocortisone-resistant thymocytes contain 3.3-fold more sialyltransferase activity compared to untreated thymocytes. PNA- thymocytes contain 8.1-fold more enzyme activity compared to the PNA+ cells. Studies with fluorescein conjugated PNA of the agglutinated and unagglutinated thymocyte fractions suggest that the trace amount of sialyltransferase activity found in the PNA+ fraction may result from 5 to 10% cross-contamination with PNA- cells. These results suggest that the cellular levels of sialyltransferase specific for asialofetuin may play an important role in T-cell differentiation.     

Field evaluation of cotton near-isogenic lines introgressed with QTLs for productivity and drought related traits

Quantitative trait loci (QTLs) for yield and drought related physiological traits, osmotic potential (OP), carbon isotope ratio (δ¹³C, an indicator of water use efficiency), and leaf chlorophyll content (Chl), were exchanged via marker-assisted selection (MAS) between elite cultivars of the two cotton species Gossypium barbadense cv. F-177 and G. hirsutum cv. Siv’on. The resulting near isogenic lines (NILs) were examined in two field trials, each with two irrigation regimes, in order to (1) evaluate the potential to improve cotton drought resistance by MAS and (2) test the role of physiological traits in plant productivity. NILs introgressed with QTLs for high yield rarely exhibited an advantage in yield relative to the recipient parent, whereas a considerable number of NILs exhibited the expected phenotype in terms of lower OP (5 out of 9), higher δ¹³C (4 out of 6) or high Chl (2 out of 3). Several NILs exhibited considerable modifications in non-targeted traits including leaf morphology, stomatal conductance and specific leaf weight (SLW). In G. barbadense genotypes, yield was correlated negatively with δ¹³C and OP and positively with stomatal conductance, SLW and Chl, whereas in G. hirsutum yield was negatively correlated with δ¹³C, SLW and Chl. This dissimilarity suggests that each of the respective species has evolved different mechanisms underlying plant productivity. We conclude that the improvement of drought related traits in cotton NILs may lead to improved drought resistance via MAS, but that conventional breeding may be necessary to combine the introduced QTL(s) with high yield potential.     

Metabolite and mineral analyses of cotton near-isogenic lines introgressed with QTLs for productivity and drought-related traits

Quantitative trait loci (QTLs) for yield and drought-related traits were exchanged via marker-assisted selection between elite cultivars of two cotton species, Gossypium barbadense (GB) cv. F-177 and Gossypium hirsutum (GH) cv. Siv'on. Three of the resultant near-isogenic lines (NILs), each introgressed with a different QTL region, expressed an advantage in osmotic adjustment (OA) and other drought-related traits relative to their recipient parents. These NILs and the parental genotypes were field-grown under well-watered and water-limited conditions, and characterized for their metabolic and mineral compositions. Comparisons were then made between (1) GB and GH genotypes, (2) the contrasting water regimes and (3) each NIL and its recipient parent. Hierarchical clustering analysis clearly distinguished between GB and GH genotypes based on either metabolite or mineral composition. Comparisons between well-watered and water-limited conditions in each of the genotypes showed differing trends in the various solutes. The greater concentrations of potassium, magnesium and calcium under water stress, when compared with well-watered conditions, may have enhanced OA or osmoprotection. All NILs exhibited significantly modified solute composition relative to their recipient parents. In particular, increased levels of alanine, aspartic acid, citric acid, malic acid, glycerol, myoinositol, threonic acid, potassium, magnesium and calcium were found under drought conditions in one or more of the NILs relative to their recipient parents. The increased values of these solutes could contribute to the superior capacity of these NILs to cope with drought.     

Does Homo neanderthalensis play a role in modern human ancestry? The mandibular evidence

Data obtained from quantifying the upper part of the mandibular ramus (the coronoid process, the condylar process, and the notch between them) lead us to conclude that Neanderthals (both European and Middle Eastern) differ more from Homo sapiens (early specimens such as Tabun II, Skhul, and Qafzeh, as well as contemporary populations from as far apart as Alaska and Australia) than the latter differs from Homo erectus. The specialized Neanderthal mandibular ramus morphology emerges as yet another element constituting the derived complex of morphologies of the mandible and face that are unique to Neanderthals. These morphologies provide further support for the contention that Neanderthals do not play a role in modern human biological ancestry, either through "regional continuity" or through any other form of anagenetic progression.     

Effect of red and far-red illuminations at the end of short days and their interaction with night-break illuminations, on flowering of Chrysanthemum morifolium plants

Flowering of chrysanthemum plants grown for 8 hr in sunlightwas delayed by 20 min of FR given prior to 16 hr dark periods.These FR illuminations increased the inhibition caused by thresholdamounts of night-break illuminations. On the other hand, 20min of R at the start of the dark period alleviated some ofthe inhibitory effects of the threshold of night-break illuminations. ¹Contribution from The Volcani Center, Agricultural ResearchOrganization, Bet Dagan, Israel, 1972 Series No. 2184 E. (Received August 26, 1972; )