A RAPD-PCR technique was used to compare genetic material from three species (Naupactus leucoloma, N. peregrinus, and N. tucumanensis) of whitefringed weevil.N. peregrinus, N. tucumanensis andN.leucoloma were consistently distinguished from each other by the presence or absence of RAPD bands.The banding profiles obtained suggested that N. peregrinus is genetically more closely related to N. leucoloma thanN.tucumanensis.The technique distinguished between three "clones" in two N. leucoloma populations sampled from Australia and New Zealand.No differences were detected between individuals within N. tucumanensis or N. peregrinus populations.The potential for RAPD-PCR technique to provide useful genetic data at the population level is discussed.
We isolated 25 independent mutants that are deficient in essential genes located in the metB-malB region of the Escherichia coli chromosome. The mutations were mapped within this region by using several F' factors and were also classified into 11 cistrons by complementation testing. There is clustering of mutations in essential genes within the metB-malB region.
We have undertaken a laboratory-based examination of the cardiovascular and thermal impact of wearing thermal (heat) protective clothing during fatiguing exercise in the heat. Seven males completed semi-recumbent, intermittent cycling (39.6°C, 45% relative humidity) wearing either protective clothing or shorts (control). Mean core and skin temperatures, cardiac frequency (f c), stroke volume (Q), cardiac output (), arterial pressure, forearm blood flow ( f), plasma volume change, and sweat rates were measured. In the clothed trials, subjects experienced significantly shorter times to fatigue (52.5 vs. 58.9 min), at lower peak work rates (204.3 vs. 277.4 W), and with higher core (37.9° vs. 37.5°C) and mean skin temperatures (37.3° vs. 36.9°C). There was a significant interaction between time and clothing on f c, such that, over time, the clothing effect became more powerful. Clothing had a significant main affect on , but not Q, indicating the higher was chronotropically driven. Despite a greater sweat loss when clothed (923.0 vs. 547.1 g.m−2·h − 1; P < 0.05), f and plasma volume change remained equivalent. Protective clothing reduced exercise tolerance, but did not affect overall cardiovascular function, at the point of volitional fatigue. It was concluded that, during moderately heavy, semi-recumbent exercise under hot, dry conditions, the strain on the unclothed body was already high, such that the additional stress imparted by the clothing ensemble represented a negligible, further impact upon cardiovascular stability.
The bacterial microbiome of psyllids has been studied for decades, with a strong focus on the primary and secondary endosymbionts capable of providing essential amino acids for the insects’ diet and therefore playing a key role in the insects’ ability to radiate on novel plant hosts. Here, we combine metabarcoding analysis of the bacterial communities hosted by psyllids with a multi-gene phylogenetic analysis of the insect hosts to determine what factors influence the bacterial diversity of the psyllids’ microbiomes, especially in the context of the dispersal and evolutionary radiation of these insects in Aotearoa New Zealand. Using multi-gene phylogenetics with COI, 18S and EF-1α sequences from 102 psyllid species, we confirmed for the first time monophyly for all the six genera of native/endemic Aotearoa New Zealand psyllids, with indications that they derive from at least six dispersal events to the country. This also revealed that, after its ancestral arrival, the genus Powellia has radiated onto a larger and more diverse range of plants than either Psylla or Ctenarytaina , which is uncommon amongst monophyletic psyllids globally. DNA metabarcoding of the bacterial 16S gene here represents the largest dataset analysed to date from psyllids, including 246 individuals from 73 species. This provides novel evidence that bacterial diversity across psyllid species is strongly associated with psyllid phylogenetic structure, and to a lesser degree to their host plant association and geographic distribution. Furthermore, while the strongest co-phylogenetic signals were derived from the primary and secondary symbionts, a signal of phylosymbiosis was still retained among the remaining taxa of the bacterial microbiome, suggesting potential vertical transmission of bacterial lineages previously unknown to have symbiotic roles.