Piecing together an integrative taxonomic puzzle: microsatellite,wing shape and aedeagus length analyses of Bactrocera dorsalis s.l. (Diptera: Tephritidae) find no evidence of multiple lineages in a proposed contact zone along the Thai/Malay Peninsula

Bactrocera dorsalis (Hendel) and B. papayae Drew & Hancock represent a closely related sibling species pair for which the biological species limits are unclear; i.e. it is uncertain if they are truely two biological species, or one biological species which has been incorrectly split taxonomically. The geographical ranges of the two taxa are thought to abut or overlap on or around the Isthmus of Kra, a recognised biogeographic barrier located on the narrowest portion of the Thai Peninsula. We collected fresh material of B. dorsalis s.l. (i.e. B. dorsalis s.s.+ B. papayae) in a north–south transect down the Thai Peninsula, from areas regarded as being exclusively B. dorsalis s.s., across the Kra Isthmus, and into regions regarded as exclusively B. papayae. We carried out microsatellite analyses and took measurements of male genitalia and wing shape, both used previously to separate the taxa. No significant population structuring was found in the microsatellite analysis, consistent with one, predominantly panmictic population. Both morphological datasets showed consistent, clinal variation along the transect, without disjunction. No evidence supported historical vicariance driven by the Isthmus of Kra, and no dataset supported the current taxonomy of two species. Rather, within and across the area of range overlap or abutment between the two species, only continuous morphological and genetic variation was recorded. Recognition that morphological traits previously used to separate these taxa are continuous, and that there is no genetic evidence for population segregation in the region of suspected species overlap, is consistent with a growing body of literature that reports no evidence of biological differentiation between these taxa.     

Genetic diversity of Philaenus spumarius and P. tesselatus (Hemiptera,Aphrophoridae): implications for evolution and taxonomy

The meadow spittlebugs Philaenus spumarius and P. tesselatus are closely related taxa with uncertain taxonomic position in the light of previous morphological, ecological, cytological and molecular research. Despite morphological homogeneity of P. spumarius (with the exception of high colour and pattern polymorphism) across its wide Holarctic range, it is possible that additional taxa (species or subspecies) exist. Philaenus spumarius is a potentially important pest in parts of its range where it was introduced. We used DNA markers to describe the genetic diversity of P. spumarius and P. tesselatus and to verify the taxonomic status of P. tesselatus and remote populations of the former species. The mitochondrial (cytochrome B) data showed that there are two main groups encompassing a northeastern (Asia and north‐central Europe) and a southwestern (Mediterranean area and western Europe, including North American specimens) clade. According to the elongation factor‐1α gene, there are three main clades: northeastern (Eurasiatic clade, E1), southeastern (east Mediterranean – Caucasus clade, E2) and southwestern (Iberian clade, E3). These two or three mitochondrial and nuclear clades could be considered as separate taxonomic units. On the other hand, all studied individuals of both species possessed the same internal transcribed spacer 2 haplotype. American specimens most probably originated from some western European populations. All studied specimens of P. tesselatus belong to the southwestern clade and western Mediterranean cluster. Therefore, together with cytological data, its species status is doubtful. To definitively solve the taxonomic status of P. tesselatus and populations of P. spumarius, further research using more samples and more genetic markers are needed.     

Rapid In Vitro Prescreen for Chelators as Potential Trypanocides Based on Growth of Crithidia fasciculata1

A rapid in vitro prescreen for Fe-binding chelators has been developed with growth of Crithidia fasciculata and the sparing of its heme requirement in a defined medium as a test system. The prescreen functions as an index of chelator-mediated Fe transport and as an index of growth inhibition, presumably by the interference with Fe and/or heme metabolism at intracellular chelatable sites. Of 161 chelators examined, 84 were active heme-sparers; 32 of these inhibited growth at low chelator concentrations. Twenty-eight other chelators inhibited growth and another 49 were inactive. Such chelating activity directed at Fe and heme targets in hemoflagellates may provide leads for chemotherapy.     

A phase II randomized clinical trial for the treatment of recalcitrant chronic leg ulcers using centrifuged adipose tissue containing progenitor cells

Background aims

Preclinical and observational reports indicate that adipose tissue (AT) is a safe and promising tool to treat non-healing venous leg ulcers (VLUs).

Excising stem samples underwater at native tension does not induce xylem cavitation

Xylem resistance to water stress‐induced cavitation is an important trait that is associated with drought tolerance of plants. The level of xylem cavitation experienced by a plant is often assessed as the percentage loss in conductivity (PLC) at different water potentials. Such measurements are constructed with samples that are excised underwater at native tensions. However, a recent study concluded that cutting conduits under significant tension induced cavitation, even when samples were held underwater during cutting. This resulted in artificially increased PLC because of what we have termed a ‘tension‐cutting artefact’. We tested the hypothesized tension‐cutting artefact on five species by measuring PLC at native tension compared with after xylem tensions had been relaxed. Our results did not support the tension‐cutting artefact hypothesis, as no differences were observed between native and relaxed samples in four of five species. In a fifth species (Laurus nobilis), differences between native and relaxed samples appear to be due to vessel refilling rather than a tension‐cutting effect. We avoided the tension‐cutting artefact by cutting samples to slightly longer than their measurement length and subsequent trimming of at least 0.5 cm of sample ends prior to measurement.