Influence of Reticulocytosis on the Course of Infection of Plasmodium chabaudi and P. berghei*

SYNOPSIS. Reticulocytosis, stimulated by the destruction of red blood cells by phenylhydrazine, altered the course of infection of both Plasmodium chabaudi and P. berghei in the mouse. P. chabaudi, lacking a preference for reticulocytes, was adversely affected when young cells were present in abundance. Parasitemias diminished and most of the animals survived the otherwise fatal infection. P. berghei preferentially invaded reticulocytes to the extent that the parasitemia became contained largely in the reticulocyte population. This was accompanied by a delay in time to death.     

Effect of Source-Sink Manipulations on the Crassulacean Acid Metabolism of Kalanchoe pinnata

The effect of manipulations of the sink-source at the above-groundlevel and girdling of source leaves was measured in 4-month-oldplants of the CAM species Kalancho pinnata (Lam.) Pers. At thisage plants developed five pairs of leaves. The upper fourthand fifth leaf pairs were not fully expanded and behaved ascarbohydrate sinks. Removal of the developing leaves induceda progressive accumulation of glucans and sugars in the matureleaves. The titratable acidity increased during the second weekbut accumulation was less than in the control plants three tofour weeks after sink removal. Similar, but more rapid, resultswere observed in mature leaves with girdled petioles. Up tothe second night after girdling dark CO₂ fixation increased,but decreased steadily afterwards. CAM Phase 4 (afternoon CO₂fixation) however, was more sensitive to girdling, being reducedby 38% on the first day, and disappearing completely 3 d aftergirdling. The glucan and sugar contents of girdled leaves increasedcontinuously after treatment, but day-night changes ceased completelyon the fifth day. Girdling also caused a considerable increasein chloroplast area, with up to 80% of their internal spaceoccupied by starch grains, leading to grana distortion. In girdledleaves, or in source leaves in plants lacking aerial carbohydratesinks, dawn-dusk changes in titratable acidity started to decreasewhen the leaf glucan content exceeded 1·0 mol equivalenthexoses kg^–1 dry weight. Increased sink strength throughshading of all leaves except one source leaf did not affectits CAM activity. The titratable acidity and non-structuralcarbohydrate content of the shaded mature leaves was reducedby around 55%. Removal of all the mature source leaves acceleratedthe maturation process of sink leaves, increasing titratableacidity at dawn and synthesis of glucans during the light period.The results support the hypothesis that CO₂ fixation in a CAMplant is controlled by accumulation of glucans in chloroplasts. Key words: CAM, glucan accumulation, sink-source ratio, CO₂ fixation     

Ants impact the energy reserves of natural enemies through the shared honeydew exploitation

1. Ants, as well as many species of parasitoids and predators, rely on sugar‐rich foods such as honeydew to fulfill their energetic needs. Thus, ants and natural enemies may interact through the shared honeydew exploitation. 2. Ant‐exclusion experiments were performed in a citrus orchard to test the hypothesis that ants may impact the energy reserves of predators and parasitoids through the competition for honeydew. Through the use of high‐performance liquid chromatography (HPLC) the level of ant activity with the energy reserves and feeding history of individual specimens collected in the field during representative days of spring, summer, and autumn were related. 3. Out of 145 Aphytis chrysomphali Mercet parasitoids captured in the field, 65% were classified as sugar‐fed and 24.7% as honeydew‐fed. In summer, when ant activity peaked, there was a significant negative correlation between the level of ant activity and the total sugar content and honeydew feeding incidence by A. chrysomphali. Out of 47 individuals of the predator Chrysoperla carnea sensu lato (Stephens), captured in the field, 55.3% were classified as sugar‐fed. We found a significant negative effect of the level of ant activity on the sugar‐feeding incidence by C. carnea in spring. 4. The present study provides evidence that ants can interfere with the energy reserves of natural enemies. This interaction may be widespread in various ecosystems with important consequences for the arthropod community composition and with practical implications for biological control given that absence of sugar feeding is detrimental for the fitness of many species of predators and parasitoids.     

A NEW MEDITERRANEAN SPECIES OF HAMINAEA LEACH, 1820 (GASTROPODA: OPISTHOBRANCHIA:CEPHALASPIDEA)

A new species of cephalaspidean gastropod from MediterraneanSea (West Naples Gulf, Italy) is described. This species, Haminaeafusari, is characterised mainly by the presence of short parapodiallobes, which cover only the anterolateral parts of the shell;the prostatic gland has two lobes separated by a narrow andcylindrical zone; the lateral teeth of the radula are all smooth;the penis has a triangular section at the apical zone and asmall sharpened tip; and the spawn is horse-shoe-shaped or coiledin a single spiral. This species is compared with all the Europeanspecies of the genus and a key to identification is provided. (Received 4 May 1992; accepted 4 January 1993)     

Genomic dissection and prioritizing of candidate genes of QTL for regulating spontaneous arthritis on chromosome 1 in mice deficient for interleukin-1 receptor antagonist

Rheumatoid arthritis is a heterogeneous disease with clinical and biological polymorphisms. IL-1RN is a protein that binds to interleukin-1 (IL-1) receptors and inhibits the binding of IL-1-alpha and IL-1-beta. IL-1RN levels are elevated in the blood of patients with a variety of infectious, immune, and traumatic conditions. Balb/c mice deficient in IL-1ra (mouse gene of IL-1RN) develop spontaneous autoimmune arthritis while DBA/1 mice deficient in IL-1ra do not. Previously, we identified a major QTL that regulates the susceptibility to arthritis in Balb/c mice with IL-1ra deficiency. In this study, we found that the QTL may contain two peaks that are regulated by two sets of candidate genes. By haplotype analysis, the total genomic regions of candidate genes were reduced from about 19 Mbp to approximately 9 Mbp. The total number of candidate genes was reduced from 208 to 21.     

Molecular systematics and evolution of the Ptinidae (Coleoptera: Bostrichoidea) and related families

The Ptinidae (Coleoptera: Bostrichoidea) are a cosmopolitan, ecologically diverse, but poorly known group of Coleoptera and, excluding a few economic pests, species are rarely encountered. This first broad phylogenetic study of the Ptinidae s.l. (i.e. including both the spider beetles and anobiids) examines relationships based on DNA sequence data from two mitochondrial genes (16S and COI) and one nuclear gene (28S), using out‐group taxa from both the Bostrichidae and Dermestidae. Topologies varied depending on the genes used and whether data were analysed with either parsimony or Bayesian methods. Generally the two mitochondrial genes supported relationships near the tips of the phylogeny, whereas the nuclear gene supported the basal relationships. The monophyly of the Ptinidae was not inferred by all of the gene combinations and analysis methods, although the combined Ptinidae and Bostrichidae have a single origin in all cases. Alternative relationships include the Ptinidae s.s. (i.e. Ptininae and Gibbiinae) as sister to the anobiids (i.e. the nine remaining subfamilies of Ptinidae s.l.) + Bostrichidae, or the Bostrichidae as sister to the Ptinidae s.s.+ anobiids. Most of the larger subfamilies within the Ptinidae are not monophyletic. Further analysis with more taxa and more genes will be required to clarify and decide upon the best hypothesis of relationships found within the clades of the Bostrichidae and Ptinidae. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 88–108.     

Opportunistic exploitation of dinosaur dung: fossil snails in coprolites from the Upper Cretaceous Two Medicine Formation of Montana

Multiple associations of fossil snails with dinosaur coprolites demonstrate that snails and dinosaurs not only shared ancient habitats but were trophically linked via dinosaur dung. Over 130 fossil snails representing at least seven different taxa have been found on or within herbivorous dinosaur coprolites from the Upper Cretaceous Two Medicine Formation of Montana. The terrestrial snail Megomphix is the most common taxon, but three other terrestrial taxa (Prograngerella, Hendersonia and Polygyrella) and three aquatic snails (Lioplacodes, ?Viviparus and a physid) also occur in coprolites. At least 46% of the shells in the faeces are whole or nearly so, indicating that most (if not all) of the snails were not ingested by dinosaurs, but were post‐depositional visitors to the dung pats. The sizeable, moist and microbially enriched dinosaur faeces would have provided both food and roosting sites for the ancient snails, and the large number of snail–coprolite associations reflect recurring, opportunistic exploitation of dung. The terrestrial taxa in the coprolites suggest that this Late Cretaceous locality included sufficiently moist detrital or vegetative cover for snails when dinosaur dung was not present. The aquatic snails probably entered the faeces during flood events. Dinosaur dung would have provided an abundant but patchy influx of resources that was probably seasonally available in the ancient environment.     

NEW AUSTRALIAN OLIGOCENE TO MIOCENE RINGTAIL POSSUMS (PSEUDOCHEIRIDAE) AND REVISION OF THE GENUS MARLU

Abstract:  Four genera of extinct ringtail possums have been reported from Australian Oligocene to Miocene sediments since 1987. The genus Marlu was described from two species, M. kutjamarpensis and M. praecursor (Woodburne, Tedford and Archer), from the Miocene Kutjamarpu Local Fauna (Leaf Locality) and late Oligocene Wadikali Local Fauna respectively, of northern South Australia. New fossil material referable to this genus has been collected from the Leaf Locality and the Oligocene to Miocene Riversleigh World Heritage Area in northwest Queensland. Three new species, Marlu karya sp. nov. from middle Miocene Riversleigh local faunas and Marlu syke sp. nov. and Marlu ampelos sp. nov. from the Leaf Locality as well as early to middle Miocene Riversleigh local faunas are described. A revision and rediagnosis of the genus and published species are made following the re-examination of referred material in conjunction with the new material. Marlu is characterized by simple dentition and synapomorphies with extant pseudocheirids such as a conjoined postmetacristid and preentocristid on m1 and the loss of the entostylid ridge. New material from middle Miocene Riversleigh deposits has been referred to M. kutjamarpensis , extending the known distribution and age of that species. Re-examination of M. praecursor has revealed the presence of a small m1 entostylid ridge, contributing further to differences between M. praecursor and all other Marlu species and raising the possibility that Marlu is paraphyletic. The new material does not contradict a sister group relationship between ' Marlu ' (excluding M. praecursor ) and the Pliocene–Pleistocene genus Pseudokoala. Homology of the pseudocheirid m1 protostylid identified in species of Paljara , Pildra and Marlu with that observed in extant species is reconsidered. The 'protostylid' of the extinct genera is herein described as the buccal stylid.