DNA as a ‘Nanomaterial’

DNA is recognized as a nanomaterial, not as a biological material, in the research field of nanotechnology. This article reviews recent research on nanowires, nanoarchitectures, computing, aptamers, biocatalysts, devices, and machines using DNA. In these works, the characteristics of DNA including facile synthesis by the solid-phase method, self-assembly, electro-conductivity, information elements, amplification, switching, molecular recognition, and catalytic functions, were appropriately applied. Multiple functions of DNA could be used simultaneously, and activated independently, by molecular switching. Therefore, the combinations of functional sequences of DNA can produce unique materials. It is obvious that the DNA molecule is one of the most promising functional nanomaterials. However, the application of DNA molecules is still under study because of the big gap that exists between theory and practice. We eagerly anticipate a ‘coming out’ of DNA due to breakthroughs in nanobiotechnology.     

Linking ‘10‐year’ herbivore cycles to the lunisolar oscillation: the cosmic ray hypothesis

The mean population cycle periods of the snowshoe hare Lepus americanus, the larch budmoth Zeiraphera diniana, and the autumnal moth Epirrita autumnata are 9.3 years, similar to the lunar nodal phase cycle. When the full/new Moon is situated close to the ecliptic plane at solstice, it interacts more strongly with the magnetosphere, which plays a crucial role in protecting the Earth against ionizing cosmic ray particles. Ionization by cosmic rays induces protein mobilization in plants, which may increase forage quality for herbivores. Series of hare/lynx population indices from Canadian provinces and an autumnal moth series from Fennoscandia correlated with the lunar nodal phase cycle with different time lags. Both the time lag and the impact of an active sun, which increases solar energetic particles, but decreases galactic cosmic ray particles, were related to radiation or the distance from the auroral oval. These insights improve our ability to explain and understand population peaks, and should also motivate further studies on the effects of cosmic rays on plant chemistry and herbivore performance.     

‘Fukusensor:’ a genetically engineered plant for reporting DNA damage in response to gamma radiation

Transgenic plants can be designed to be ‘phytosensors’ for detection of environmental contaminants and pathogens. In this study, we describe the design and testing of a radiation phytosensor in the form of green fluorescence protein (GFP)‐transgenic Arabidopsis plant utilizing a DNA repair deficiency mutant background as a host. Mutant lines of Arabidopsis AtATM (At3g48190), which are hypersensitive to gamma irradiation, were used to generate stable GFP transgenic plants in which a gfp gene was under the control of a strong constitutive CaMV 35S promoter. Mutant and nonmutant genetic background transgenic plants were treated with 0, 1, 5, 10 and 100 Gy radiation doses, respectively, using a Co‐60 source. After 1 week, the GFP expression levels were drastically reduced in young leaves of mutant background plants (treated by 10 and 100 Gy), whereas there were scant visible differences in the fluorescence of the nonmutant background plants. These early results indicate that transgenic plants could serve in a relevant sensor system to report radiation dose and the biological effects to organisms in response to radionuclide contamination.     

The concept of superfetation: a critical review on a ‘myth’ in mammalian reproduction

Superfetation is understood as another conception during an already ongoing pregnancy. This implies the existence of young of different developmental stages within the female reproductive tract during certain periods of pregnancy. Nevertheless, a clear definition of the term as well as distinct criteria to identify the occurrence of superfetation in a species is missing. The variable anatomy of mammalian reproductive tracts seems to make the occurrence of superfetation more or less likely but impedes the simple evaluation of whether it is present or not. Additionally, adequate determination methods are missing or are difficult to apply at the right time. Superfetation or rather superfetation‐like pregnancies are reported for numerous species including humans, livestock and rodents. The usual criteria to assume a case of superfetation include the finding of discordantly developed young within the uterus during post mortem or parturition of young after a birth interval shorter than the assumed pregnancy length. Often the occurrence of superfetation is concluded because other explanations of reproductive artifacts are missing. Even severe reproductive pathologies are often confused with superfetation. True superfetation or superfetation as a reproductive strategy may exist in some mammals. In the American mink (Neovison (Mustela) vison) and the European badger (Meles meles) superfetation occurs in combination with embryonic diapause. In the European brown hare (Lepus europaeus), superfetation has long been assumed to exist but evidence is still controversial. Superfetation definitely occurs in certain species of poeciliid and zenarchopterid fish, some of which also exhibit viviparity and maternal care. In mammals, the evolution of such a reproductive mechanism poses many interesting evolutionary, endocrine, microbial and immunological questions that require further investigation. Here we review the scant and at times ancient literature on this poorly understood topic. The different manifestations of superfetation are defined and reliable criteria to detect superfetation are outlined. Also, the differentiation of superfetation into a reproductive strategy or as a disrupted, abnormal reproductive function is discussed. Due to the different discussed functional aspects of superfetation, it is appropriate to establish a more detailed scheme to classify the true natural superfetation cases into superfertilization, superconception and superfetation proper. To date, there is no mammal species known for which superfetation proper in terms of finding discordantly developed fetuses has been conclusively demonstrated to be not only a rare occurence but an evolved reproductive strategy.     

Contamination effects by a ‘conventional’ and a ‘biodegradable’ lubricant oil on infaunal recruitment to Antarctic sediments: A field experiment

To investigate the impacts of synthetic lubricants on Antarctic infaunal communities, a field experiment was setup near Australia's Casey Station, East Antarctica. Two types of synthetic lubricants were tested: an ‘Unused’ and ‘Used’ conventional synthetic lubricant, and an alternative marketed as ‘biodegradable’. Clean defaunated sediment was contaminated with the lubricants, decanted into trays, and deployed by divers onto the seabed in a randomised block design. Sediments were sampled 5 and 56 weeks after deployment. After 5 weeks, benthic assemblages that had recruited to the lubricant contaminated sediments were significantly different to those in ‘Control’ sediments, and differences were more pronounced after 56 weeks. Total number of individuals did not significantly differ between treatments after 5 weeks. However, after 56 weeks total individuals in the ‘Control’ sediments were significantly greater than in the contaminated sediments. Nototanais antarcticus (tanaid) and to a lesser extent Monoculodes sp. (gammarid), Tanaid sp. IV and Eudorella sp. (cumacean) had significantly higher abundances in the control sediments after 56 weeks compared to the contaminated sediments. Copepods numerically dominated the benthic assemblages at both sampling times; however, their abundance did not significantly differ across treatments. The community recruiting to the contaminated sediments remained different from that in the ‘Control’ sediments for the duration of the experiment (1 year). The ‘biodegradable’ lubricant was just as environmentally harmful to the Antarctic infauna as the ‘conventional’ lubricant currently used at Australia's Antarctic stations. Our results demonstrate that changes to recruitment are one of the potential environmental consequences of a lubricant spill to Antarctic benthic communities, and reinforce the importance of preventative oil spill management and effective clean-up procedures. Further monitoring of this field experiment will provide much needed information about the long-term impacts by synthetic lubricants in the Antarctic marine environment.     

Chrysanthemum expressing a linalool synthase gene ‘smells good’, but ‘tastes bad’ to western flower thrips

Herbivore‐induced plant volatiles are often involved in direct and indirect plant defence against herbivores. Linalool is a common floral scent and found to be released from leaves by many plants after herbivore attack. In this study, a linalool/nerolidol synthase, FaNES1, was overexpressed in the plastids of chrysanthemum plants (Chrysanthemum morifolium). The volatiles of FaNES1 chrysanthemum leaves were strongly dominated by linalool, but they also emitted small amount of the C11‐homoterpene, (3E)‐4,8‐dimethyl‐1,3,7‐nonatriene, a derivative of nerolidol. Four nonvolatile linalool glycosides in methanolic extracts were found to be significantly increased in the leaves of FaNES1 plants compared to wild‐type plants. They were putatively identified by LC‐MS‐MS as two linalool–malonyl–hexoses, a linalool–pentose–hexose and a glycoside of hydroxy–linalool. A leaf‐disc dual‐choice assay with western flower thrips (WFT, Frankliniella occidentalis) showed, initially during the first 15 min of WFT release, that FaNES1 plants were significantly preferred. This gradually reversed into significant preference for the control, however, at 20–28 h after WFT release. The initial preference was shown to be based on the linalool odour of FaNES1 plants by olfactory dual‐choice assays using paper discs emitting pure linalool at similar rates as leaf discs. The reversal of preference into deterrence could be explained by the initial nonvolatile composition of the FaNES1 plants, as methanolic extracts were less preferred by WFT. Considering the common occurrence of linalool and its glycosides in plant tissues, it suggests that plants may balance attractive fragrance with ‘poor taste’ using the same precursor compound.     

The origin of a ‘true’ worker caste in termites: phylogenetic evidence is not decisive

The phylogenetic study of the origin of a ‘true’ worker caste in termites by Thompson et al. [J. Evol. Biol. 13 (2000) 869] did not take into account all possibilities of character coding and character optimization on the phylogenetic tree. Actually, contrary to the authors' statements, the phylogenetic evidence presented does not permit to answer decisively most of the questions asked concerning the origin and evolution of worker castes in termites. Particular attention was paid to assumptions implied by the coding of the characters of interest, namely concerning the homology between pseudergates and a ‘true’ worker caste and the kind of the cockroach life type.     

‘Black’ and ‘white’ death: burials in a time of Ebola in Freetown,Sierra Leone

The article examines experiences of the 2014‐15 Ebola crisis in Freetown, Sierra Leone, through an analysis of the performance of burials. While most of the city's residents had no contact with the virus, ‘Ebola’ was inescapable, owing to the onerous state of emergency regulations imposed by national and international authorities. All burials, regardless of the cause of death, were to be performed by newly established official teams operating according to unfamiliar biomedical and bureaucratic protocols. Burials became emblematic of the crisis through presenting a conflict between local practices and novel procedures, which was coded locally in a complex racial language of ‘black’ and ‘white’, recalling a long regional history of violent integration into the Atlantic World. Building on long‐standing anthropological discussion on the relationship between ‘good’ death and social order, the article explores how burials became sites around which opposing ‘orders’ were experienced, negotiated, and reconciled in locally meaningful ways.     

Novel evidence suggests that a ‘Rickettsia felis‐like’ organism is an endosymbiont of the desert flea,Xenopsylla ramesis

Fleas are acknowledged vectors and reservoirs of various bacteria that present a wide range of pathogenicity. In this study, fleas collected from wild rodents from the Negev desert in southern Israel were tested for RickettsiaDNA by targeting the 16S rRNA (rrs) gene. Thirty‐eight Xenopsylla ramesis, 91 Synosternus cleopatrae and 15 Leptopsylla flea pools (a total of 568 fleas) were screened. RickettsiaDNA was detected in 100% of the X. ramesis and in one S. cleopatrae flea pools. None of L. algira flea pools was found positive. All positive flea pools were further characterized by sequencing of five additional genetic loci (gltA, ompB, ompA, htrA and fusA). The molecular identification of the positive samples showed all sequences to be closely related to the ‘Rickettsia felis‐like’ organisms (99–100% similarities in the six loci). To further investigate the association between ‘R. felis‐like’ and X. ramesis fleas, ten additional single X. ramesis adult fleas collected from the wild and five laboratory‐maintained X. ramesis imago, five larva pools (2–18 larvae per pool) and two egg pools (18 eggs per pool) were tested for the presence of ‘R. felis‐like’ DNA. All samples were found positive by a specific ompAPCR assay, confirming the close association of this Rickettsia species with X. ramesis in all its life stages. These results suggest a symbiotic association between ‘Rickettsia felis‐like’ and X. ramesis fleas.     

Review of ‘The Plant List,a working list of all plant species’

The Plant List ( http://www.theplantlist.org/ ) is an on‐line database of plant names that aims to be comprehensive for all described plant species. Version 1 of The Plant List includes 1 040 426 plant name records, of which 298 900 are accepted names. The Plant List is the product of a consortium of the Royal Botanic Gardens, Kew, and the Missouri Botanical Garden. In this review, I evaluate the use of this plant taxonomic database for plant ecologists. The web interface of The Plant List allows a quick search for species names and corresponding synonyms. Moreover, users are able to download search or browse results to compile a customized checklist of plant names. The combination of a straightforward web design and the possibility to download search results provides a valuable resource of plant nomenclature information for a wide range of plant ecologists.     

Chaperone overload is a possible contributor to ‘civilization diseases’

Molecular chaperones dampen the effect of damaging mutations that would otherwise be removed from the population by natural selection. Here, I propose that the development of modern medical practice depressed this process, leading to a rise of phenotypically silent mutations in the genome. The background of misfolded proteins increases during ageing and, by competition, prevents the chaperone-mediated buffering of silent mutations. Phenotypically exposed mutations contribute to a more-abundant manifestation of multigene-diseases. This ‘chaperone overload’ hypothesis emphasizes the need for efficient ways to enhance chaperone capacity in ageing subjects, and will hopefully lead to the identification and ‘repair’ of silent mutations.     

‘Bridges to cash’: channelling agency in mobile money

Encountered by mobile money professionals – industry and philanthropic actors seeking to bring mobile phone‐enabled financial products to poor people in the ‘developing world’ – the authors move together with new collaborators to inquire into a problem they had been grappling with for some time. This is the problem of agency; specifically, the agency of ‘mobile money agents’, the people ‘on the ground’ or ‘in the field’ who form a crucial function in permitting others to put cash into an electronic money transfer system and pull cash out of it. These ‘human ATMs’ or ‘bridges to cash’ become the object of analytical scrutiny for mobile money experts and anthropologists. This article takes that analytical scrutiny – and not mobile money agents themselves – as its object. It seeks to understand how ‘agency’ inflects debates over money, its meaning and its pragmatics, and its transformation in new communicative infrastructures, and how it might inform anthropology and political struggles over money and payment.