Age‐specific maternal effects interact with larval food supply to modulate life history in Coleomegilla maculata

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Identification and characterization of simple sequence repeat (SSR) markers from Fragaria×ananassa expressed sequences

The availability of expressed sequence data derived from gene discovery programmes enables mining for simple sequence repeats (SSRs), providing useful genetic markers for crop improvement. These markers are inexpensive, require minimal labour to produce and can frequently be associated with functionally annotated genes. This study reports on the development and characterization of expressed sequence tag (EST)–SSR markers in the cultivated strawberry, Fragaria×ananassa. Fourteen primer pairs were assessed for polymorphism in 13 F.×ananassa genotypes. The markers show reliable amplification and considerable polymorphism, demonstrating the utility of EST–SSRs for genetic analysis of commercial strawberry germplasm.     

Infection of Hydra by Microsporidia

A microsporidian infection in a laboratory clone of Hydra littoralis has been observed, and the parasite has been tentatively identified as a species of Plistophora . Infected hydra continue to bud and regenerate normally and show no significant physiological or morphological changes. Sexual crossing of infected and non-infected animals shows that the infection is transmitted by the ovum but not by the sperm. Continuous exposure of infected hydra to Fumidil B in solution resulted in the disappearance of all Plistophora spores after a five week period of treatment, and the clones of the treated animals have remained parasite-free for more than a year.     

Characterization of simple sequence repeat markers derived in silico from Brassica rapa bacterial artificial chromosome sequences and their application in Brassica napus

A collaborative Brassica rapa genome sequencing project is currently in progress to aid the identification of agronomically important traits in Brassica species. As an initial stage, the ends of over 110 000 bacterial artificial chromosome clones were sequenced and mined for simple sequence repeats (SSRs). We present the characterization of 40 of these SSRs and their application in Brassica napus. The markers were screened against six Brassica species and Arabidopsis, and demonstrated reliable amplification, genome specificity, cross‐amplification and significant polymorphism. These SSRs will be useful for genetic analysis of Brassica germplasm.     

TIME COURSE OF BIOCHEMICAL AND IMMUNOHISTOLOGICAL ALTERATIONS DURING EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS

A comprehensive biochemical, immunological and histological study was undertaken during different stages of experimental allergic encephalomyelitis (EAE). Wistar rats with EAE induced by sensitization with bovine myelin showed a maximum decrease of body weight 14–16 days post-inoculation (dpi), coincident with the appearance of the paralysis symptom (acute period). Quantitation of some brain components indicated a temporal dissociation among the alterations observed. The higher diminution of myelin basic protein (MBP) occurred at 6 dpi and then increased to reach 21 dpi, a normal value. Also, the activity of 2′,3′-cyclic nucleotide 3′-phosphohydrolase was reduced by 40% with respect to control animals only at 6 dpi. The total lipid content was normal; however, among the individual lipids, sulfatides were principally degraded during the acute stage but the amount of cerebrosides was decreased during the recovery period (29–40 dpi). Free cholesterol was similar in both groups of animals, whereas cholesterol esters were detected in EAE animals from 14 to 40 dpi. Central nervous system meningeal and parenchymal infiltration with mononuclear cells was recognized principally at 14 dpi, but some of cells were still present at 40 dpi. Deposits of immunoglobulins in the infiltrated regions as well as in spinal cord motor neurons were observed among 14–29 dpi. Total circulating antibodies to MBP began to increase at 14 dpi, reaching a plateau at 21 dpi and then maintaining this value until 40 dpi. However, the population of anti-MBP antibodies that also recognizes the neuronal protein synapsin was only present at 14 dpi. The present results suggest that the neurological symptoms can be related to some early changes in the myelin membrane followed by alterations involving neuronal structures. The existence of immunological factors against some epitopes in MBP that also recognize a synaptosomal protein might account, at least in part, for the axonal damage and disruption of the normal interneuronal activity in EAE and lead together with the alterations in some specific myelin constituents and the concomitant CNS inflammatory process to the observed hindlimb paralysis. Copyright © 1996 Elsevier Science Ltd     

Oxygen uptake in coprophilous beetles (Aphodius, Geotrupes, Sphaeridium) at low oxygen and high carbon dioxide concentrations

Abstract. The rate of O₂ consumption was measured in five coprophilous beetle species (common in Denmark) at O₂ concentrations from 1–21%. With the exception of the mainly soil-living Geotrupes spiniger (Marsham) (Geotrupidae), these beetles are probably exposed to severe hypoxia in fresh cattle pats. Aphodius fossor (Linnaeus), A. contaminatus (Herbst) (Aphodiidae) and Sphaeridium lunatum Fabricius (Hydrophilidae) maintained normal movements and a normal rate of 0₂ uptake (for at least 30 min) at only 1% O₂. There is no evidence, therefore, that the beetles switch to anaerobic metabolism under these conditions. This ability to regulate respiration, and hence to extract 0₂ at very low concentrations, is exceptional even among terrestrial arthropods living in soil or other potentially hypoxic substrates. In A. rufipes (Linnaeus), respiration declined at ambient concentrations below 2% O₂, and in G. spiniger the ability to regulate respiration seemed to fail at even higher concentrations. In four of the species (G. spiniger was not tested), about 11% CO₂ (the level in a dung pat at 2% O₂) did not affect the O₂ uptake at 2% O₂.     

Effects of Exogenous Thyroxine on Statolith Synthesis and Resorption in Aurelia

Aurelia ephyrae which were maintained in thyroxine during theirmetamorphosis from the polyp state and another group of ephyraewhich were in thyroxine forfour and eight days of starvation,had significantly reduced numbers of statoliths as comparedwith control ephyrae in equimolar concentrations of iodine andin artificial sea water. We conclude, therefore, that thyroxinesignificantly affects the mineralization and demineralizationof statocytes resulting in changes in statolith numbers. A mineralization role of thyroxine in other invertebrates hasnot been reported in spite of the fact that thyroxine and itsprecursors, monoiodotyrosine and diiodotyrosine, have been locatedin numerous invertebrates, particularly in mineralizing areassuch as developing shells. On the other hand, an important roleof thyroxine in mineralization and demineralization of bonesand teeth of vertebrates including humans, has been known forsome time. The specific role of thyroxine in affecting mineralizationin vertebrates is not known, due perhaps to the presence ofmany other hormones and second messengers which also affectmineralization. The use of the relatively simple Aurelia statolithtest systems and the exploration for other invertebrate mineralizingsystems which respond to thyroxine will hopefully lead to abetter understanding of the basic mechanisms of thyroxine actionin mineralizing systems in the future.