Developmental Capacity of Aneuploid Xenopus Species Hybrids

Diploid as well as triploid Xenopus interspecific hybrids generate aneuploid eggs because of the presence, at meiosis, of univalent chromosomes which are presumably distributed at random. Zygotes obtained from such eggs, fertilized by either normal or UV-irradiated sperm, were analysed for their developmental capacities. All monosomics die in the course of embryogenesis, whereby optimum capacities correspond closely with those observed in monosomic mammalian embryos, especially in mice. In contrast, hyperdiploid Xenopus are relatively viable: although many die exhibiting the'haploid syndrome'or various other abnormalities, 8% of them reach metamorphosis, and 1–2% become adults. Of the latter, the karyotype was established in 13 individuals. Among them, 8–16 supernumerary chromosomes were found to be present.     

The Native Dialectica aemula (Meyrick) and the Introduced Dialectica scalariella (Zeller) (Lepidoptera: Gracillariidae) in Australia: Characterisation of Two Closely Related Species on Boraginaceae

Two gracillariid leaf miners of the genus Dialectica Walsingham are present in Australia on plants belonging to the family Boraginaceae, one a native species here identified as Dialectica aemula (Meyrick) which was originally described from India, and the Palaearctic Dialectica scalariella (Zeller) or Echium leaf miner, deliberately introduced as a biological control agent for Echium plantagineum L. or Paterson's Curse. Differential diagnoses are given for the two species, and they are comprehensively illustrated to enable identification. In contrast to the externally indistinguishable adults, the cocoons of the two species differ significantly in shape and colour and a colour plate allows easy identification.     

A preliminary assessment of the conservation status of Cypripedium species in the wild

The conservation of few plants produces such an emotive response as that of hardy slipper orchids of the genus Cypripedium. The genus, comprising 45 species and two varieties, is holarctic in distribution with the centre of diversity in China. Much is known about the status of some species and their populations in Europe and North America, but little information is available on the Asiatic and Mexican species. Most cypripediums are showy orchids and are well represented in herbaria, allowing an estimate of the present distribution, frequency and conservation status of the known species to be made. The authors conclude that having considered the number of herbarium specimens, nearly half of the genus may be considered threatened and in need of some legal protection if the plants are to survive in the wild. They identify a need to examine the conservation status of the taxa in in this genus more closely, and outline two important conservation tools that may help efforts to this end: the IUCN Red List Categories and Criteria for the Amendment of the Appendices of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).     

The importance of passerine birds as tick hosts and in the transmission of Borrelia burgdorferi,the agent of Lyme disease: a case study from Scotland

Borrelia burgdorferi sensu lato (s.l.) is the causative agent of Lyme borreliosis, the most common tick‐borne zoonosis of humans in Europe and North America. Here, we assessed the relative importance of different passerine bird species as tick hosts and their contribution to the B. burgdorferi s.l. transmission cycle in a rural residential area in Scotland. We caught 1229 birds of 22 species during the tick‐questing season. On average, 29% carried larval ticks (0.8 larvae per individual) and 5% carried nymph ticks (0.06 nymphs per individual). All attached ticks tested were Ixodes ricinus. Using a nested‐PCR, we found that 20% of nymphs tested positive to B. burgdorferi s.l. and all these were of the genospecies Borrelia garinii. We identified two new bird species carrying infected nymphs: Eurasian Siskin Carduelis spinus and European Greenfinch Carduelis chloris. Ground‐foraging species were more important than arboreal species in hosting I. ricinus nymphs and B. burgdorferi s.l. Common Blackbirds Turdus merula were the most common hosts, with Song Thrushes Turdus philomelos, Dunnocks Prunella modularis, European Greenfinches and Chaffinches Fringilla coelebs also hosting high rates of infection.     

Reproductive ecology of the endemic Lecocarpus pinnatifidus (Asteraceae) in an isolated population in the Galápagos Islands

Lecocarpus pinnatifidus is an endemic member of the Asteraceae occurring on only one island in the Galápagos archipelago. The capitula are large with female ray florets and male disc florets. They are self-compatible but this study suggests fruit set is pollen limited. Visits from Xylocopa darwini and other larger insect pollinators are rare, and small insects seem to be the main pollinators. Small insects carry few pollen grains and most likely mediate self-pollinations. Self-compatibility and seed set after selfing are the most common reproductive strategy in the Galápagos Islands and L. pinnatifidus seemingly fits well into this group.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 171–180.     

Elevated CO2 decreases seed germination in Arabidopsis thaliana

The impact of elevated [CO₂] on seed germination was studied in different genotypes of Arabidopsis thaliana from natural populations. Two generations of seeds were studied: the maternal generation was produced in the greenhouse (present-day conditions), the offspring generation was produced in two chambers where the CO₂ concentration was either the present atmospheric concentration (about 350 ppm) or elevated (700 ppm). The seeds were tested for proportion of germinated seeds and mean germination time in both chambers to study the impact of elevated [CO₂] during seed production and germination. Elevated [CO₂] during maturation of seeds on the mother-plants decreased the proportion of germinated seeds, while elevated [CO₂] during germination had no effect on the proportion of germinated seeds. However, when seeds were both produced and germinated under elevated [CO₂] (situation expected by the end of next century), germination was slow and low. Moreover, the effect of the [CO₂] treatment differs among genotypes of Arabidopsis: there is a strong treatment × genotype interaction. This means that there is ample genetic variance for a selective response modiying the effects of high levels of [CO₂] in natural populations of Arabidopsis thaliana. The outcome at the community level will depend on what seeds are available, when they germinate and the resulting competition following germination.     

A Brominating and Hydroxylating Peroxidase from the Red Alga Cystoclonium purpureum

A particulate enzyme displaying peroxidase activity has been extracted from the red alga Cystoclonium purpureum (Huds.) Batt. The enzyme preparation was shown to contain ferri-protoporphyrin IX through its formation of formic acid hemochromogen with absorption maxima at 399, 402, 555 and 600 nm. The preparation catalyses the formation of 3-bromo-p-hydroxybenzyl alcohol from p-hydroxybenzyl alcohol in the presence of H₂O₂ and NaBr at pH = 5.4. The formation of 3-bromo-p-hydroxybenzyl alcohol was measured by gas chromato-graphy-mass spectrometry. At pH = 6.7, 4,5-di-hydroxybenzyl alcohol was formed. Addition of homogentisic acid stimulated the formation of dihydroxybenzyl alcohol and suppressed the brominating reaction. Iodide inhibits the enzyme. The results are consistent with a two-site model of the enzyme.     

Molecular phylogeny of Sericostomatoidea (Trichoptera) with the establishment of three new families

We inferred the phylogenetic relationships among 58 genera of Sericostomatoidea, representing all previously accepted families as well as genera that were not placed in established families. The analyses were based on five fragments of the protein coding genes carbamoylphosphate synthetase (CPSase of CAD), isocitrate dehydrogenase (IDH), Elongation factor 1a (EF‐1a), RNA polymerase II (POL II) and cytochrome oxidase I (COI). The data set was analysed using Bayesian methods with a mixed model, raxml , and parsimony. The various methods generated slightly different results regarding relationships among families, but the shared results comprise support for: (i) a monophyletic Sericostomatoidea; (ii) a paraphyletic Parasericostoma due to inclusion of Myotrichia murina, leading to synonymization of Myotrichia with Parasericostoma; (iii) a polyphyletic Sericostomatidae, which is divided into two families, Sericostomatidae sensu stricto and Parasericostomatidae fam.n. ; (iv) a polyphyletic Helicophidae which is divided into Helicophidae sensu stricto and Heloccabucidae fam.n. ; (v) hypothesized phylogenetic placement of the former incerta sedis genera Ngoya, Seselpsyche and Karomana; (vi) a paraphyletic Costora (Conoesucidae) that should be divided into several genera after more careful examination of morphological data; (vii) reinstatement of Gyrocarisa as a valid genus within Petrothrincidae. A third family, Ceylanopsychidae fam.n. , is established based on morphological characters alone. A hypothesis of the relationship among 14 of the 15 families in the superfamily is presented. A key to the families is presented based on adults (males). Taxonomic history, diagnosis, habitat preference and distribution data for all sericostomatoid families are presented. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:CF6A6B9F‐6A72‐4265‐BD09‐3A710DFCD7B1 .