Ketomethylureas. A new class of angiotensin converting enzyme inhibitors

The design rationale for a new series of tripeptide derived angiotensin converting enzyme (ACE) inhibitors, which we term "ketomethylureas", is described. Analogs of tripeptide substrates (i.e. N-benzoyl-Phe-Ala-Pro) in which the nitrogen atom of the scissile amide bond and the adjacent asymmetric carbon atom of the penultimate amino acid residue are formally transposed give rise to this novel class of inhibitors. The most potent ketomethylureas inhibit ACE with I50 values in the nM range.     

Development and reproduction of Myzus persicae and Aphis fabae (Hom., Aphididae) on selected weed species surrounding sugar beet fields

Abstract:   Myzus persicae (Sulzer) and Aphis fabae (Scop.) are two major aphid species colonizing sugar beet. They have a very wide host range adapting to a large number of plant families and species. A series of cage experiments, conducted under 'winter' and 'summer' growth chamber conditions, showed that both species have the potential to use winter and summer weeds that are usually present in the vicinity of and within sugar beet fields as secondary hosts. Among all the weeds tested, Veronica hederifolia L. and Solanum nigrum L. were the most suitable for M. persicae . Although Brassica kaber (DC.) Wheeler was the weed species associated to the highest reproduction rate of this aphid, V. hederifolia showed a higher intrinsic rate of population increase due to the shorter prereproductive period of the aphid. Amsynckia intermedia Fish. and Mey and Amaranthus retroflexus L. were the most suitable weed hosts for A. fabae .     

Interannual patterns of avian diseases in wild New Zealand avifauna near conservation areas

The past few years have seen a noticeable increase in the emergence of infectious diseases in wildlife, especially vector-borne diseases, presenting a challenge for the conservation of endangered species. One such vector-borne disease, avian malaria (Plasmodium spp.) is on the rise in New Zealand avifauna, threatening bird populations that are among the most extinction-prone in the world. Furthermore, recent reports have outlined an increase in deaths of native iconic bird species specifically due to this disease. In order to help manage breakouts of this pathogen at a local scale, we need a better understanding of potential drivers of the emergence of avian malaria in wild New Zealand avifauna. Here, we set to test the role of climatic drivers in synchronizing contacts between avian hosts and vectors, assess the temporal stability of transmission dynamics between years, and determine the role of introduced species in causing spill-over of this pathogen towards native species. Our study focused on three sites that were sampled regularly during two consecutive years in the austral summer, each site being adjacent to a breeding colony of Yellow-eyed penguins (Megadyptes antipodes). Our results reveal an overall temporal stability of avian malaria incidence patterns, with a decrease in infection throughout the austral summer for both sampled years. Moreover, we highlight a phylogenetic signal among sampled bird species, with introduced species being more heavily infected by avian malaria than their native counterparts. In contrast, we found no effect of the two climatic drivers investigated, temperature and rainfall, on mosquito abundance. Our results suggest a strong effect of alien species acting as reservoirs for diseases spilling-over towards immunologically naïve species, and provide conservation managers with a critical timeframe to control avian malaria breakouts.     

Affinity purification and subunit structure of soya bean lactate dehydrogenase

The lactate dehydrogenase (LDH) from soya bean has been purified to homogeneity by affinity chromatography. The enzyme was purified by sequential adsor     

The central role of phosphorylcholine in the metabolism of epidermis in the guinea-pig, Cavia porcellus.

1. CDP-choline, which has been identified for the first time in epidermis, accumulates when skin is deprived of glucose. 2. ATP and fatty acids depress uptake of [32P]orthophosphate into phosphorylcholine in skin maintained in vitro.     

Fossilized eggs from the Pennsylvanian of Illinois

Nine siderite concretions from the Middle Pennsylvanian, Francis Creek Shale (Carbondale Formation, Desmoinesian Series, West‐phalian C‐D), in the Mazon Creek area, Will‐Kankakee Counties, Illinois, U.S.A. preserve clusters of impressions of small eggs. Differential staining of the matrix suggests that the eggs were originally spawn within gelatinous strings containing 1 or 2 rows of eggs. Unfortunately, these egg impressions lack the diagnostic features needed to identify the zoological taxon (taxa) from which they originated.     

Lipoproteins produced by ApoE-/- astrocytes infected with adenovirus expressing human ApoE

We have developed an astrocyte cell culture system that is attractive for the study of apoE structure and its impact on astrocyte lipoproteins and neuronal function. Primary astrocytes from apoE-/- mice were infected with adenovirus expressing apoE3 or apoE4 and the nascent lipoproteins secreted were characterized. The nascent apoE-containing astrocyte particles were predominantly the size of plasma high density lipoprotein (HDL). ApoE4, in contrast to apoE3, appeared to be distributed in two distinct lipoprotein peaks and the apoE4-containing lipoproteins contained significantly more radiolabeled triglyceride. On electron micrographs the astrocyte particles were both discoidal and spherical in shape with a prevalence of stacked discs in apoE3 particles, but single discs and larger spheres in apoE4 particles. The apoE4 discs were significantly wider than apoE3 discs. These properties of the astrocyte lipoproteins are similar to those obtained from apoE isoform transgenic mice. Astrocyte lipoproteins containing apoE3, but not apoE4, stimulated neurite outgrowth in Neuro-2a cells. These studies suggest that the isoform-specific effects of apoE lipoproteins may involve differences in particle size and composition. Finally we demonstrate the usefulness of this system by expressing a truncated apoE3 (delta202-299) mutant and show preliminary data indicating that a liver X receptor agonist promotes HDL output by the astrocytes without an increase in apoE in the media. This cell culture system is more flexible and allows for more rapid expression of apoE mutants.     

Competitive Inhibition of γ-Aminobutyric Acid Synaptosomal Uptake by 4-(4'-Azidobenzoimidylamino)butanoic Acid

Abstract: 4-(4'-Azidobenzoimidylamino)butanoic acid (ABBA) is a potent inhibitor of rat brain synaptosomal [³H]γ-aminobutyric acid uptake. K₁ values were calculated to be 8 μM and 16 μM with respect to the high-affinity and the low-affinity uptake processes. These values are of the same order as those reported for nipecotic acid and guvacine, which until now have been the most potent uptake inhibitors available. Since ABBA contains a phenyl group, it might be capable of penetrating the blood-brain barrier, thus becoming a useful GABA mimetic.