Patterns of association, nestedness, and species co-occurrence of helminth parasites in the greater kudu, Tragelaphus strepsiceros, in the Kruger National Park, South Africa, and the Etosha National Park, Namibia

The helminth parasites of the greater kudu from the Kruger National Park (KNP), South Africa, and the Etosha National Park (ENP), Namibia, were examined to determine the major patterns of spatial and demographic variation in community structure and to evaluate nonrandomness in parasite community assembly. Nonmetric multidimensional scaling ordination procedures were used to test for differences in parasite community composition between hosts of the 2 parks and between hosts of different demographic groups within KNP. Infracommunities within KNP were also examined for patterns of nonrandomness using 2 null models, i.e., nestedness and species co-occurrence. Infracommunities of KNP and ENP were significantly different from each other, as were infracommunities of different host demographic groups within KNP. Parasite species in the greater kudu from KNP displayed significant levels of nestedness and were found to co-occur less frequently than expected by chance; however, this lack of co-occurrence was significant only when all demographic groups were considered. When restricted to any particular age class, co-occurrence patterns could not be distinguished from random. Overall, these data suggest that biogeography and host demographics are important factors in determining community organization of helminth parasites in the greater kudu.     

Reexamination of the role of ubiquitin-like modifier ISG15 in the phenotype of UBP43-deficient mice

UBP43/USP18 was described as a specific protease that removes conjugated ubiquitin-like modifier ISG15 from target proteins. The severe phenotype of UBP43(-/-) mice characterized by premature death, brain cell injury, and deregulated STAT1 signaling was ascribed to an enhanced conjugation of ISG15. In contrast, no phenotypic changes were detected in ISG15(-/-) mice. To verify the role of ISG15 in the phenotype of UBP43(-/-) mice, we employed mice deficient for both ISG15 and UBP43. Here, we show that the phenotype of UBP43(-/-) mice was not rescued by the absence of ISG15, as evident from unchanged mortality, neurological symptoms, and occurrence of hydrocephalus. Also, the reported hypersensitivity of UBP43(-/-) mice to an interferon inducer, poly(I . C), was ISG15 independent. Furthermore, no evidence for a role of ISG15 in the modulation of STAT1 signaling or in the resistance against lymphocytic choriomeningitis virus and vesicular stomatitis virus was found. Presented results clearly demonstrate that the phenotypic alterations of UBP43(-/-) mice are not caused by the lack of ISG15 deconjugation and must be due to another, non-ISG15-mediated molecular mechanism.     

Fumonisins--novel mycotoxins with cancer-promoting activity produced by Fusarium moniliforme

Cultures on corn of Fusarium moniliforme MRC 826 are known to cause leukoencephalomalacia in horses and to be toxic and hepatocarcinogenic in rats. Culture material of this F. moniliforme isolate has also been shown to exhibit cancer-promoting activity in a short-term cancer initiation-promotion bioassay with diethylnitrosamine-initiated rats and the induction of gamma-glutamyl-transpeptidase-positive (GGT+) foci as an endpoint after 4 weeks of promotion. This bioassay was used as a monitoring system to isolate cancer-promoting compounds from cultures of F. moniliforme MRC 826. Culture material was successively extracted with ethyl acetate and CH3OH-H2O (3:1). Most of the cancer-promoting activity was recovered in the CH3OH-H2O extract and remained in the aqueous phase following partitioning of this extract between CH3OH-H2O (1:3) and CHCl3. The CH3OH-H2O fraction was chromatographed on an Amberlite XAD-2 column, and the active fraction was eluted with CH3OH. This fraction was chromatographed on a silica gel column with CHCl3-CH3OH-CH3COOH (6:3:1) as eluent and further purified on a C18 reverse-phase column. Two pure compounds were isolated, and these have been chemically characterized and given the trivial names fumonisin B1 and B2. At least 2 g of the major compound fumonisin B1 was purified from 1 kg of culture material. Fumonisin B1 in the diet (0.1%) significantly (P less than 0.001) induced the formation of GGT+ foci in the livers of initiated as well as noninitiated rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coupling factor activity of the purified pea mitochondrial F1-ATPase

The pea cotyledon mitochondrial F1-ATPase was released from the submitochondrial particles by a washing procedure using 300 mM sucrose/2 mM Tricine (pH 7.4). The enzyme was purified by DEAE-cellulose chromatography and subsequent sucrose density gradient centrifugation. Using polyacrylamide gel electrophoresis under non-denaturing conditions, the purified protein exhibited a single sharp band with slightly lower mobility than the purified pea chloroplast CF1-ATPase. The molecular weights of pea mitochondrial F1-ATPase and pea chloroplast CF1-ATPase were found to be 409 000 and 378 000, respectively. The purified pea mitochondrial F1-ATPase dissociated into six types of subunits on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Most of these subunits had mobilities different from the subunits of the pea chloroplast CF1-ATPase. The purified mitochondrial F1-ATPase exhibited coupling factor activity. In spite of the observed differences between CF1 and F1, the mitochondrial enzyme stimulated ATP formation in CF1-depleted pea chloroplast membranes. Thus, the mitochondrial F1 was able to substitute functionally for the chloroplast CF1 in reconstituting photophosphorylation.     

Saproxylic moths reveal complex within-group and group-environment patterns

We investigated saproxylic moths of the family Tineidae, a neglected group inhabiting wood-decaying fungi and dead wood, within the Bia?owie?a Primeval Forest in Poland. Study data were obtained from the collection of 280 fruiting bodies of wood-decaying fungi and the subsequent rearing of adults. Spatial and statistical distribution of saproxylic moths, relationship among species and the influence of environment reflected by interaction with tree and fungal species together with tree and stand level characteristics were studied. Fifteen species and 533 individuals of saproxylic moths were reared. The fungal species, number of fruiting bodies and standing position of a tree influenced species richness. Moth abundance was influenced by fungal species, coniferous trees, increasing tree diameter, number of fruiting bodies and brown rot. Moth abundance was also enhanced by standing dead trees located in managed forests with higher canopy closure. Analyses indicate that several moth species favor a particular rot type and that some fungi host a richer fauna than others. Furthermore, our results indicate mutually independent fungal colonization events by saproxylic moth species, and thus a possible mechanism exists for competition avoidance with other saproxylic moths. Saproxylic moths revealed complex within-group patterns that responded differently to environmental variables. Thus, potential conservation of these organisms requires various approaches including ecosystem management, especially in the context of addressing their diverse habitat requirements.     

Faster onset of action with topical levocabastine than with oral cetirizine

This international multicentre, open-label, parallel-group trial was undertaken to compare the therapeutic efficacy and tolerability of topical levocabastine and oral cetirizine in patients with perennial allergic rhinoconjunctivitis, with particular reference to the comparative onset of action of the two drugs. A total of 207 patients were randomized to receive either levocabastine nasal spray (0.5 mg/ml, two sprays in each nostril twice daily) plus levocabastine eye drops as required (0.5 mg/ml, one drop in each eye twice daily p.r.n.) or cetirizine orally (10 mg once daily) with a treatment duration of 2 weeks. Onset of action was found to be significantly more rapid with levocabastine than with cetirizine for both nasal and ocular symptoms (p < 0.001). Within 15 min of study drug administration, 36% of levocabastine-treated patients reported relief from nasal symptoms and 32% relief from ocular symptoms compared with 10% and 17% of patients on cetirizine, respectively. At 1 h, the percentages of patients reporting relief were 76% and 38% for nasal symptoms, and 81% and 48% for ocular symptoms in the levocabastine and cetirizine treatment groups, respectively. At 8 h there were no differences between the two treatments. Overall therapeutic efficacy was found to be comparable in the two treatment groups over the 2-week study period with no significant intergroup differences in symptom severity or global therapeutic efficacy. Both drugs were well tolerated with no significant differences in the incidence or type of adverse reactions between the two groups. In conclusion, levocabastine eye drops and nasal spray are as effective and well tolerated as oral cetirizine for the treatment of perennial allergic rhinoconjunctivitis with the advantage of a significantly faster onset of action for both nasal and ocular symptoms.     

The appetence behaviour of two South African paralysis-inducing ixodid ticks

The appetence responses of the ixodid ticksIxodes rubicundus andRhipicephalus punctatus to various stimuli were quantified under laboratory conditions. A greater percentage ofI. rubicundus generally responded to the different stimuli at lower than at higher temperatures while the converse was usually true forR. punctatus. Radiation heat and shadowing evoked a response in the greatest percentage ofI. rubicundus, whereas CO₂ and host odour were responsible for a similar reaction inR. punctatus. A single perturbation of the substrate caused more than 50% ofI. rubicundus to respond while constant perturbation resulted in a progressive decrease in the proportion of ticks reacting. Significantly moreR. punctatus thanI. rubicundus were attracted to a CO₂ trap and theR. punctatus were also attracted to the trap over a greater distance. Significantly more older than younger ticks of both species responded to the various stimuli.     

Zur vergleichenden Physiologie der vikariierenden Ericaceen

Zusammenfassung Erica carnea undCalluna vulgaris einerseits,Rhododendron hirsutum undRhododendron ferrugineum anderseits wurden auf ihren Mineralstoffgehalt hin (K, Ca, Mg) untersucht. Bei jedem dieser Paare wurden Standorte aufgesucht, an denen die vikariierenden Arten ausnahmsweise unmittelbar nebeneinander oder in Mischbeständen wuchsen. Erica enthält stets (relativ zum Kalium) etwas mehr Calcium und Magnesium alsCalluna. Es ist denkbar, daß ein erhöhtes Bedürfnis der erstgenannten Pflanze für Erdalkali-Ionen vorliegt, das die ökologischen Unterschiede bedingt.Zwischen den beidenRhododendron-Arten. ließ sich kein Unterschied im Mineralstoffgehalt feststellen. Die für die Verteilung dieser Arten verantwortlichen physiologischen Unterschiede müssen entweder außer-ordentlich geringfügig sein oder in einem anderen Bereich des Stoffwechsels liegen.Herrn Prof. Dr.Lothar Geitler zum 70. Geburtstag gewidmet.     

The plant mitochondrial F1-ATPase. The identity of the delta' (20 kDa) subunit

The N-terminal amino acid sequence of the 20 kDa (delta') subunit of the turnip (Brassica napus L.) mitochondrial F1-ATPase has been determined. Comparison of the sequence obtained with those of the epsilon subunits of chloroplast CF1, E. coli F1 and the delta subunit of bovine F1 shows that the turnip delta' subunit is another member of this family of homologous proteins. The delta' subunit of sweet potato F1-ATPase [(1989) J. Biol. Chem. 264, 3183-3186] is very similar to the turnip sequence and thus can also be considered to belong to this family.