Biologically relevant effects of mRNA amplification on gene expression profiles

Background  

Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results.     

Chromosome phylogeny of the subfamily Pitheciinae (Platyrrhini,Primates) by classic cytogenetics and chromosome painting

Background  

The New World monkey (Platyrrhini) subfamily Pitheciinae is represented by the genera Pithecia, Chiropotes and Cacajao. In this work we studied the karyotypes of Pithecia irrorata (2n = 48) and Cacajao calvus rubicundus (2n = 45 in males and 2n = 46 in females) by G- and C-banding, NOR staining and chromosome painting using human and Saguinus oedipus whole chromosome probes. The karyotypes of both species were compared with each other and with Chiropotes utahicki (2n = 54) from the literature.     

Direct anti-metastatic efficacy by the DNA enzyme Dz13 and downregulated MMP-2, MMP-9 and MT1-MMP in tumours

The DNA enzyme Dz13, targeted against the oncogene c-Jun, is capable of inhibiting various model tumours in mice albeit in ectopic models of neoplasia. In previous studies using orthotopic models of disease, the inhibitory effects of Dz13 on secondary growth was a direct result of growth inhibition at the primary lesion site. Thus, the direct and genuine effects on metastasis were not gauged. In this study, Dz13 was able to inhibit both locoregional and distal metastasis of tumour cells in mice, in studies where the primary tumours were unaffected due to the late and clinically-mimicking nature of treatment commencement. In addition, the effect of Dz13 against tumours has now been extended to encompass breast and prostate cancer. Dz13 upregulated the matrix metalloproteinase (MMP)-2 and MMP-9, and decreased expression of MT1-MMP (MMP-14) in cultured tumour cells. However, in sections of ectopic tumours treated with Dz13, both MMP-2 and MMP-9 were downregulated. Thus, not only is Dz13 able to inhibit tumour growth at the primary site, but also able to decrease the ability of neoplastic cells to metastasise. These findings further highlight the growing potential of Dz13 as an antineoplastic agent.     

A temperate pollinator with high thermal tolerance is still susceptible to heat events predicted under future climate change

1. Mutualisms may be particularly vulnerable to climate change as interacting species are likely to respond differently, which could destabilise interactions. 2. Temperate zone insects typically experience mean temperatures below their thermal optima, making them less vulnerable than tropical insects to small increases in mean temperature. However, they are likely to experience a higher frequency of extreme heat events, putting mutualism persistence in jeopardy. 3. This study investigated the potential impacts of climate change on Pleistodontes imperialis, a temperate Australian fig wasp that pollinates Port Jackson figs (Ficus rubiginosa). Wasp emergence and longevity were measured at temperatures ranging from those commonly experienced in nature (25 °C) to high values (> 40 °C) that are currently infrequent, but which are becoming more common with climate change. 4. Wasp emergence was unaffected by temperatures up to 39 °C, but it declined drastically above 39 °C. Adult longevity was unaffected by temperatures up to 30 °C, but decreased at 35 °C and above. Low humidity reduced wasp longevity across all temperatures. 5. Fitness reductions were observed at temperatures ～5 °C above the summer daily mean maximum, suggesting that P. imperialis has a high thermal tolerance, but is vulnerable to extreme heat. Figs located in the shade may provide protected microhabitats under hot conditions. 6. Tropical pollinators may be threatened by small increases in mean temperature. In contrast, it is shown here that temperate pollinators may face a different primary threat from climate change – the increasing frequency of extreme heat events – despite their higher thermal tolerances.     

YAP‐TEAD signaling promotes basal cell carcinoma development via a c‐JUN/AP1 axis

The mammalian Hippo signaling pathway, through its effectors YAP and TAZ, coerces epithelial progenitor cell expansion for appropriate tissue development or regeneration upon damage. Its ability to drive rapid tissue growth explains why many oncogenic events frequently exploit this pathway to promote cancer phenotypes. Indeed, several tumor types including basal cell carcinoma (BCC) show genetic aberrations in the Hippo (or YAP/TAZ) regulators. Here, we uncover that while YAP is dispensable for homeostatic epidermal regeneration, it is required for BCC development. Our clonal analyses further demonstrate that the few emerging Yap‐null dysplasia have lower fitness and thus are diminished as they progress to invasive BCC. Mechanistically, YAP depletion in BCC tumors leads to effective impairment of the JNK‐JUN signaling, a well‐established tumor‐driving cascade. Importantly, in this context, YAP does not influence canonical Wnt or Hedgehog signaling. Overall, we reveal Hippo signaling as an independent promoter of BCC pathogenesis and thereby a viable target for drug‐resistant BCC.     

Host–endoparasitoid–endosymbiont relationships: concealed Strepsiptera provide new twist to Wolbachia in Australian tephritid fruit flies

Wolbachia are widespread endosymbionts that affect arthropod reproduction and fitness. Mostly maternally inherited, Wolbachia are occasionally transferred horizontally. Previously, two Wolbachia strains were reported at low prevalence and titres across seven Australian tephritid species, possibly indicative of frequent horizontal transfer. Here, we performed whole-genome sequencing of field-caught Wolbachia-positive flies. Unexpectedly, we found complete mitogenomes of an endoparasitic strepsipteran, Dipterophagus daci, suggesting that Wolbachia in the flies are linked to concealed parasitization. We performed the first genetic characterization of D. daci and detected D. daci in Wolbachia-positive flies not visibly parasitized, and most but not all Wolbachia-negative flies were D. daci-negative, presumably reflecting polymorphism for the Wolbachia infections in D. daci. We dissected D. daci from stylopized flies and confirmed that Wolbachia infects D. daci, but also found Wolbachia in stylopized fly tissues, likely somatic, horizontally transferred, non-heritable infections. Furthermore, no Wolbachia cif and wmk genes were detected and very low mitogenomic variation in D. daci across its distribution. Therefore, Wolbachia may influence host fitness without reproductive manipulation. Our study of 13 tephritid species highlights that concealed early stages of strepsipteran parasitization led to the previous incorrect assignment of Wolbachia co-infections to tephritid species, obscuring ecological studies of this common endosymbiont and its horizontal transmission by parasitoids.     

Absence of the symbiont Candidatus Midichloria mitochondrii in the mitochondria of the tick Ixodes holocyclus

OprG of Pseudomonas aeruginosa is a member of the very large and widely distributed but poorly characterized OmpW (PF0392) family of outer membrane proteins. It was established here that OprG was highly transcribed in anaerobic environments rich in iron via the ANR regulator. In the absence of OprG, P. aeruginosa was significantly less cytotoxic toward human bronchial epithelial cells. Planar bilayer studies indicated that purified OprG formed cationic-selective channels with a conductance of 500 pS in 1 M KCl; however, contrary to previous reports, OprG did not appear to be involved in either iron or antibiotic uptake.