Patterns of diversification in New Zealand Stylidiaceae

Phylogenetic analysis of ITS and rbcL sequences show that New Zealand Stylidiaceae fall into two distinct lineages differing in species richness. Each lineage represents a unique dispersal event to New Zealand occurring at different times during the evolutionary history of the family. One lineage comprises seven species of Forstera and Phyllachne, while the other consists solely of Oreostylidium subulatum. The origin of the Forstera/Phyllachne lineage in New Zealand is equivocal; either a South American or a Tasmanian origin is equally parsimonious. Possible sister groups are F. bellidifolia in Tasmania and P. uliginosa in South America. Oreostylidium subulatum has an Australian origin. In our analyses O. subulatum is nested in a clade composed entirely of species of Stylidium, almost all of which are endemic to Australia. Species of Phyllachne share a cushion habit with the outgroup Donatia (Donatiaceae) that may have preadapted them to alpine environments in New Zealand. The New Zealand Stylidiaceae have small, white, actinomorphic flowers that are well adapted to the unspecialized pollinator fauna. Forstera and Phyllachne share this trait with Donatia; however, the small, white flowers of Oreostylidium are a dramatic departure from the colorful, highly specialized flowers of Stylidium.     

Meiotic exchange within and between chromosomes requires a common Rec function in Saccharomyces cerevisiae.

We used haploid yeast cells that express both the MATa and MAT alpha mating-type alleles and contain the spo13-1 mutation to characterize meiotic recombination within single, unpaired chromosomes in Rec+ and Rec- Saccharomyces cerevisiae. In Rec+ haploids, as in diploids, intrachromosomal recombination in the ribosomal DNA was detected in 2 to 6% of meiotic divisions, and most events were unequal reciprocal sister chromatid exchange (SCE). By contrast, intrachromosomal recombination between duplicated copies of the his4 locus occurred in approximately 30% of haploid meiotic divisions, a frequency much higher than that reported in diploids; only about one-half of the events were unequal reciprocal SCE. The spo11-1 mutation, which virtually eliminates meiotic exchange between homologs in diploid meiosis, reduced the frequency of intrachromosomal recombination in both the ribosomal DNA and the his4 duplication during meiosis by 10- to greater than 50-fold. This Rec- mutation affected all forms of recombination within chromosomes: unequal reciprocal SCE, reciprocal intrachromatid exchange, and gene conversion. Intrachromosomal recombination in spo11-1 haploids was restored by transformation with a plasmid containing the wild-type SPO11 gene. Mitotic intrachromosomal recombination frequencies were unaffected by spo11-1. This is the first demonstration of a gene product required for recombination between homologs as well as recombination within chromosomes during meiosis.     

Late Cenozoic diversification of the austral genus Lagenophora (Astereae,Asteraceae)

Lagenophora (Astereae, Asteraceae) has 14 species in New Zealand, Australia, Asia, southern South America, Gough Island and Tristan da Cunha. Phylogenetic relationships in Lagenophora were inferred using nuclear and plastid DNA regions. Reconstruction of spatio‐temporal evolution was estimated using parsimony, Bayesian inference and likelihood methods, a Bayesian relaxed molecular clock and ancestral area and habitat reconstructions. Our results support a narrow taxonomic concept of Lagenophora including only a core group of species with one clade diversifying in New Zealand and another in South America. The split between the New Zealand and South American Lagenophora dates from 11.2 Mya [6.1–17.4 95% highest posterior density (HPD)]. The inferred ancestral habitats were openings in beech forest and subalpine tussockland. The biogeographical analyses infer a complex ancestral area for Lagenophora involving New Zealand and southern South America. Thus, the estimated divergence times and biogeographical reconstructions provide circumstantial evidence that Antarctica may have served as a corridor for migration until the expansion of the continental ice during the late Cenozoic. The extant distribution of Lagenophora reflects a complex history that could also have involved direct long‐distance dispersal across southern oceans. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177 , 78–95.     

Treatment with tumour infiltrating lymphocytes and interleukin-2 in patients with metastatic melanoma: A pilot study

Tumour infiltrating lymphocytes (TIL) were isolated and expanded from biopsy samples of 4 patients with metastatic melanoma. The patients were treated with autologous expanded TIL and continuous or bolus infusion of Interleukin 2 (IL-2) at a dose of 18 × 10⁶ International Units/m²/day for 5 days starting 36–48 hours after administration of cyclophosphamide at a dose of 1 g/m². The number of TIL infused ranged from 10¹⁰ to 5,56 × 10¹⁰ cells. Two patients had stable disease (SD) lasting for 2 1/2 and 4 months respectively and they died 24 and 13 months after therapy. One patient died during therapy due to a pseudomonas septicaemia and another patient developed progressive disease (PD). He died 3 months after the start of therapy. The side effects were substantial but most of them were reversible upon cessation of the treatment.The majority of the expanded TIL of all patients were of the CD8+ phenotype. Cutaneous metastases from two patients, removed after treatment with IL-2 and TIL, showed moderate lymphocytic infiltration also mainly of CD8+ T cells.The treatment with IL-2 and TIL is feasible, but further investigations should continue in an attempt to improve the efficacy of the therapy, to reduce toxicity and to diminish the costs and labour of the culture methods.     

Domain loss facilitates accelerated evolution and neofunctionalization of duplicate snake venom metalloproteinase toxin genes

Gene duplication is a key mechanism for the adaptive evolution and neofunctionalization of gene families. Large multigene families often exhibit complex evolutionary histories as a result of frequent gene duplication acting in concordance with positive selection pressures. Alterations in the domain structure of genes, causing changes in the molecular scaffold of proteins, can also result in a complex evolutionary history and has been observed in functionally diverse multigene toxin families. Here, we investigate the role alterations in domain structure have on the tempo of evolution and neofunctionalization of multigene families using the snake venom metalloproteinases (SVMPs) as a model system. Our results reveal that the evolutionary history of viperid (Serpentes: Viperidae) SVMPs is repeatedly punctuated by domain loss, with the single loss of the cysteine-rich domain, facilitating the formation of P-II class SVMPs, occurring prior to the convergent loss of the disintegrin domain to form multiple P-I SVMP structures. Notably, the majority of phylogenetic branches where domain loss was inferred to have occurred exhibited highly significant evidence of positive selection in surface-exposed amino acid residues, resulting in the neofunctionalization of P-II and P-I SVMP classes. These results provide a valuable insight into the mechanisms by which complex gene families evolve and detail how the loss of domain structures can catalyze the accelerated evolution of novel gene paralogues. The ensuing generation of differing molecular scaffolds encoded by the same multigene family facilitates gene neofunctionalization while presenting an evolutionary advantage through the retention of multiple genes capable of encoding functionally distinct proteins.