Ultrastructural visualization of low-density lipoproteins during receptor binding and cellular endocytosis

Human fibroblasts possess surface receptors which have a high affinity for low-density lipoproteins (LDL). However, previous studies have not provided direct ultrastructural visualization of LDL bound to the receptor. To permit direct observation of unlabeled LDL during receptor binding and cellular endocytosis, we examined several fixative regimens which employ lipophilic stains. Staining with tannic acid, an oxidized form of ruthenium red, or potassium ferrocyanide imparted sufficient contrast to individual molecules of LDL to permit high-resolution electron microscopy of receptor binding and endocytosis. The LDL molecule was observed in immediate contact with the receptor and the coated vesicle, indicating that receptor-ligand binding occurs by short-range interactions.     

Antifungal diene in leaves of various avocado cultivars

Leaves (both young and mature) of seventeen commercial avocado (Persea americana) cultivars have been analysed monthly throughout the year to measure the concentration and seasonal variation of the antifungal diene (Z,Z)-2-hydroxy-4-oxohenicosa-12,15-dien-1-yl acetate (persin).     

Plant regeneration of Solanum lycopersicoides Dun. from stem explants,callus and suspension cultures

Protocols were established for achieving plant regeneration from stem internode, callus, and cell suspension cultures of Solanum lycopersicoides Dun. Two accessions of S. lycopersicoides exhibited different responses as to callus formation on various media, requirement of gibberellic acid for shoot regeneration, and ability to grow in suspension culture. The optimum medium for initiation and maintenance of cell suspension cultures was Murashige and Skoog [9] medium with 15 mg l^– NAA. For shoot regeneration, of three cytokinins tested, zeatin was found most effective relative to number, rapidity of response and overall quality of shoots. Shoot regeneration from stem explants, callus and suspension cultures was optimum on MS + 3.0 mg l^–1 zeatin + 0.1 mg l^–1 gibberellic acid.Michigan Agricultural Experiment Station Journal Article No. 11589.     

<Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis> chloroplasts express an orally immunogenic protein targeting the p210 epitope implicated in atherosclerosis immunotherapies

Key message

An algae-based vaccine model against atherosclerosis was developed with positive findings in terms of antigen yield and immunogenicity in mouse.

Abstract

Several immunotherapies against atherosclerosis have been evaluated at the preclinical level thus far, with some of them currently under evaluation in clinical trials. In particular, the p210 epitope from ApoB100 is known to elicit atheroprotective responses. Considering that Chlamydomonas reinhardtii is an attractive host for the production and delivery of subunit vaccines, in this study a chimeric protein consisting of the B subunit of the cholera toxin and the p210 epitope from ApoB100 (CTB:p210) has been expressed in C. reinhardtii chloroplast as an attempt to establish an oral vaccine candidate against atherosclerosis. The Chlamydomonas-made CTB:p210 protein was successfully expressed at levels of up to 60 µg per g of fresh weight biomass. The antigenic activity of the CTB and the p210 moiety was preserved in the CTB:p210 chimera. Moreover the algae-made CTB:p210 showed an immunogenic activity, when orally administered to BALB/c mice, as evidenced the presence of anti-p210 serum antibodies in mice treated with the algae-derived CTB:p210. The antibody response lasts for at least 80 days after the last boost. This experimental model is proposed as a convenient tool in the development of low cost atherosclerosis vaccines of easy compliance and friendly delivery. Further studies will determine the therapeutic potential of this algae-made vaccine in atherosclerosis animal models.

     

Kleptoparasitism in foraging gentoo penguins <Emphasis Type="Italic">Pygoscelis papua</Emphasis>

An ongoing challenge in marine top predator research is understanding processes that are responsible for patterns that are often derived from land-based access to individuals. The use of animal-borne camera loggers, however, is proving useful in this regard as researchers can directly observe species and habitat-associated interactions. During an ongoing study investigating the foraging ecology of gentoo penguins (Pygoscelis papua) at the Falkland Islands, we observed the first attempted underwater intraspecific kleptoparasitism event for a penguin. This was revealed through a bird deployed with an animal-borne camera logger. Although unsuccessful in its attempt, the new reported behaviour highlights a novel interaction and further demonstrates the value of cameras in better understanding the ecology of marine vertebrates.     

Osteology Supports a Stem-Galliform Affinity for the Giant Extinct Flightless Bird Sylviornis neocaledoniae (Sylviornithidae,Galloanseres)

The giant flightless bird Sylviornis neocaledoniae (Aves: Sylviornithidae) existed on La Grande Terre and Ile des Pins, New Caledonia, until the late Holocene when it went extinct shortly after human arrival on these islands. The species was generally considered to be a megapode (Megapodiidae) until the family Sylviornithidae was erected for it in 2005 to reflect multiple cranial autapomorphies. However, despite thousands of bones having been reported for this unique and enigmatic taxon, the postcranial anatomy has remained largely unknown. We rectify this deficiency and describe the postcranial skeleton of S. neocaledoniae based on ~600 fossils and use data from this and its cranial anatomy to make a comprehensive assessment of its phylogenetic affinities. Sylviornis neocaledoniae is found to be a stem galliform, distant from megapodiids, and the sister taxon to the extinct flightless Megavitiornis altirostris from Fiji, which we transfer to the family Sylviornithidae. These two species form the sister group to extant crown-group galliforms. Several other fossil galloanseres also included in the phylogenetic analysis reveal novel hypotheses of their relationships as follows: Dromornis planei (Dromornithidae) is recovered as a stem galliform rather than a stem anseriform; Presbyornis pervetus (Presbyornithidae) is the sister group to Anseranatidae, not to Anatidae; Vegavis iaai is a crown anseriform but remains unresolved relative to Presbyornis pervetus, Anseranatidae and Anatidae. Sylviornis neocaledoniae was reconstructed herein to be 0.8 m tall in a resting stance and weigh 27–34 kg. The postcranial anatomy of S. neocaledoniae shows no indication of the specialised adaptation to digging seen in megapodiids, with for example, its ungual morphology differing little from that of chicken Gallus gallus. These observations and its phylogenetic placement as stem galliforms makes it improbable that this species employed ectothermic incubation or was a mound-builder. Sylviornis neocaledoniae can therefore be excluded as the constructor of tumuli in New Caledonia.