The phylogenetic status of arthropods, as inferred from 18S rRNA sequences

Partial 18S rRNA sequences of five chelicerate arthropods plus a crustacean, myriapod, insect, chordate, echinoderm, annelid, and platyhelminth were compared. The sequence data were used to infer phylogeny by using a maximum-parsimony method, an evolutionary-distance method, and the evolutionary-parsimony method. The phylogenetic inferences generated by maximum-parsimony and distance methods support both monophyly of the Arthropoda and monophyly of the Chelicerata within the Arthropoda. These results are congruent with phylogenies based on rigorous cladistic analyses of morphological characters. Results support the inclusion of the Arthropoda within a spiralian or protostome coelomate clade that is the sister group of a deuterostome clade, refuting the hypothesis that the arthropods represent the "primitive" sister group of a protostome coelomate clade. Bootstrap analyses and consideration of all trees within 1% of the length of the most parsimonious tree suggest that relationships between the nonchelicerate arthropods and relationships within the chelicerate clade cannot be reliably inferred with the partial 18S rRNA sequence data. With the evolutionary-parsimony method, support for monophyly of the Arthropoda is found in the majority of the combinations analyzed if the coelomates are used as "outgroups." Monophyly of the Chelicerata is supported in most combinations assessed. Our analyses also indicate that the evolutionary-parsimony method, like distance and parsimony, may be biased by taxa with long branches. We suggest that a previous study's inference of the Arthropoda as paraphyletic may be the result of (a) having two few arthropod taxa available for analysis and (b) including long-branched taxa.      

Neo-clerodane-type diterpenoids from Salvia keerlii

From the aerial parts of Salvia keerlii two new neo-clerodane diterpenoids have been isolated. Their structures: 8,12(R)epoxyneo-cleroda-3,13(14)-diene-18,19:15,16-diolide, kerlin and 7-acetoxy-12(R)hydroxyneoclerodane-3,13(14)-diene-18,19:15,16-diolide, kerlinolide, have been established by spectroscopic means. X-ray diffraction analysis was performed for kerlin.     

Evidence for thyroglobulin-reactive T cells in good responder mice.

Trehalose dimycolates and monomycolates isolated from a variety of Mycobacteria species as well as synthetic trehalose mycolates and trehalose behenylbehenate produced granulomatous responses in the lungs of mice. Trehalose alone or mycolic acids or their methyl esters, however, did not. These data suggest that the sugar moiety of these defined fatty acid esters is required for the production of this cellular inflammatory reaction. When mice were challenged with virulent Mycobactorium tuberculosis they showed increased resistance against infection during the time when the granulomatous response was greatest.     

Growth hormone locus expands and diverges after the separation of New and Old World Monkeys

While most mammals including the prosimians have a single copy of the growth hormone (GH) gene, anthropoids possess a cluster of GH-related genes. Throughout the evolution of the main anthropoid groups [New World Monkeys (NWM), Old World Monkeys (OWM), and apes], two features stand out of the GH loci. The first is the appearance of chorionic somatommamotropin hormone (CSH) genes within the OWM lineage and the second is the expansion of the loci intergenic regions in the OWM and apes. In relation with this loci expansion, the NWM possess intergenic regions of homogeneous lengths (3.5 kb). In contrast, heterogeneous lengths (6 and 13 kb) have been reported for species of the OWM. At the present, none of the OWM genomic GH loci organizations have been described. Here, we report the genomic organization of the GH locus in the rhesus monkey, this locus has six GH-related genes separated by five intergenic regions. The 5' end gene (GH-1) encodes for the pituitary GH and is followed by CSH-1, GH-2, CSH-2, CSH-3 and CSH-4 genes. The five intergenic regions have heterogeneous lengths and also present more or less the same Alu distribution as the human GH locus. To analyze the events that contributed to the extension of the intergenic regions of the GH locus and the emergence of the regulatory elements, the five GH locus intergenic regions of the spider monkey (NWM) were sequenced. The results of comparing the loci from both species suggest that the long intergenic regions (13 kb) of the rhesus GH locus share a common ancestor with the 3.5 kb intergenic regions of the spider monkey. However, the observed increased length of the former is due to an insertion (approximately 8.7 kb) at their 3' end. Interestingly in this insert, we discovered a DNA element resembling the enhancer of the CSH genes of the human GH locus. On the other hand, we observed that the short intergenic regions (6 kb) increased by a different recombination event.     

Abietane diterpenoids from the roots of some Mexican Salvia species (Labiatae): chemical diversity, phytogeographical significance, and cytotoxic activity

From the roots of some Mexican Salvia species, classified in subgenus Jungia, several diterpenoids belonging to abietane (i.e., 3-7), salvifolane (9-->20,10-->6)-diabeoabietane) (i.e., 2), and totarane (i.e., 10) carbocyclic skeletons were isolated together with two 20-nor- and one 6,7-secoabietane derivatives, 1 and 9, and 8, respectively. While compounds 2-10 were previously known from different sources, compound 1 is a new 20-norabietane derivative, whose structure was deduced by spectroscopic means and confirmed by X-ray-diffraction analysis. The phytogeographical significance of the distribution of 20-norabietanic diterpenoids in the genus suggested an evolutionary link between the Chinese and New-World Salvias. Compounds 2 and 8 were tested for cell-growth inhibition activity against several human cancer cell lines and human normal lymphocytes, while 2 showed a moderate cytotoxic activity, 8 exhibited a moderate yet selective activity against leukemia cell line.     

A new comprehensive database of alien plant species in Chile based on herbarium records

There is an urgent need for comprehensive national databases on alien plant species, especially in developing countries. Despite the fact that plant invasions are considered a major threat to biodiversity, they have been poorly studied or not considered a conservation priority in South America. We aim to assess alien plant distribution in Chile, using the first comprehensive public alien plant database, and discuss the implications of using herbarium records to develop national databases of alien plants. We used herbarium records to assemble a comprehensive national database of alien plants. We calculated the number of alien and native species and specimens recorded in each 10 × 10 km cell. We evaluated sampling efforts and tested for relationships between alien and native species collections, as well as other spatial patterns along the latitudinal gradient. Alien and native species richness was positively correlated. Alien plants were mostly collected in central Chile, with few species collected in both the extreme north and south. However, native plants were strongly collected in central Chile, as well as in both extremes of the country. Alien and native plants followed the same pattern of accumulation along the latitudinal gradient, with native plants being relatively more collected than alien plants. Herbarium records provide valuable baseline information to evaluate plant species distribution. However, there are important gaps in this database, (e.g. variable sampling effort for alien and native plants, incomplete information on life-history traits). Given scientists and land managers increasing demand for baseline information and the high cost of collecting such data in developing countries, herbarium records should be used more frequently for research and management of plant invasions.     

Weighted compromise trees: a method to summarize competing phylogenetic hypotheses

A new consensus method for summarizing competing phylogenetic hypotheses, weighted compromise, is described. The method corrects for a bias inherent in majority‐rule consensus/compromise trees when the source trees exhibit non‐independence due to ambiguity in terminal clades. Suggestions are given for its employment in parsimony analyses and tree resampling strategies such as bootstrapping and jackknifing. An R function is described that can be used with the programming language R to produce the consensus.     

Host plants of the tarnished plant bug (Heteroptera: Miridae) in Central Texas

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), has taken on added importance as a pest of cotton in the Cotton Belt after successful eradication efforts for the boll weevil (Anthonomus grandis grandis Boheman). Because the Southern Blacklands region of Central Texas is in advanced stages of boll weevil eradication, blooming weeds and selected row crops were sampled during a 3-yr study to determine lygus species composition and associated temporal host plants. L. lineolaris was the sole lygus species in the region. Thirteen previously unreported host plants were identified for L. lineolaris, of which 69% supported reproduction. Rapistrum rugosum L. Allioni and Ratibida columnifera (Nuttall) Wooton and Standley were primary weed hosts during the early season (17 March to 31 May). Conyza canadensis L. Cronquist variety canadensis and Ambrosia trifida L. were primary weed hosts during the midseason (1 June to 14 August) and late-season (15 August to 30 November), respectively. Sisymbrium irio L. and Lamium amplexicaule L. sustained L. lineolaris populations during the overwintering period (1 December to 16 March). The proportion of females and numbers of nymphs found in R. rugosum, C. canadensis, A. trifida, and S. irio suggests these weeds supported reproductive adults during the early, mid-, and late season and overwintering period, respectively. Medicago sativa L. was the leading crop host for L. lineolaris; Glycine max L. Merrill did not yield L. lineolaris. Few L. lineolaris were collected in Gossypium hirsutum L. These results provide a more comprehensive assessment of host plants contributing to L. lineolaris populations in central Texas.