Epstein-Barr virus episome-based promoter function in human myeloid cells.

Epstein-Barr virus (EBV) episomal replicons offer an expeditious means for amplifying transfected genes in human cells. A panel of EBV episomes was constructed to assess the relative utility of five distinct eukaryotic promoter elements for high level and inducible gene expression in stably transfected human myeloid leukemia cells. The Rous sarcoma virus 3' long terminal repeat (LTR) was most highly suited for EBV episome-based gene expression, whereas the lymphopapilloma virus and the SV40 early regulatory elements exhibited substantially lower activities. Chemically responsive promoter elements, such as the SV40 early, human metallothionein IIA and rat GRP78 gene promoters, retained their inducibility when EBV episome-based. Differences in gene expression obtained with the episomes reflected differential promoter activity rather than significant variations in episome copy numbers per cell. These observations provide guidelines for the optimal design of EBV episomal expression vectors for human expression work.     

Tn4351 transposes in Bacteroides spp. and mediates the integration of plasmid R751 into the Bacteroides chromosome.

The gene for resistance to erythromycin and clindamycin, which is carried on the conjugative Bacteroides plasmid, pBF4, has been shown previously to be part of an element (Tn4351) that transposes in Escherichia coli. We have now introduced Tn4351 into Bacteroides uniformis 0061 on the following two suicide vectors: (i) the broad-host-range IncP plasmid R751 (R751::Tn4351) and (ii) pSS-2, a chimeric plasmid which contains 33 kilobases of pBF4 (including Tn4351) cloned into the IncQ plasmid RSF1010 and which is mobilized by R751. When E. coli HB101, carrying either R751::Tn4351 or R751 and pSS-2, was mated with B. uniformis under aerobic conditions, Emr transconjugants were detected at a frequency of 10(-6) to 10(-5) (R751::Tn4351) or 10(-8) to 10(-6) (R751 and pSS-2). In matings involving pSS-2, all Emr transconjugants contained simple insertions of Tn4351 in the chromosome, whereas in matings involving R751::Tn4351, about half of the Emr transconjugants had R751 cointegrated with Tn4351 in the chromosome. Of the Emr transconjugants, 13% were auxotrophs. Bacteroides spp. which had R751 cointegrated with Tn4351 in the chromosome did not transfer R751 or Tn4351 to E. coli HB101 or to isogenic B. uniformis, nor did the intergrated R751 mobilize pE5-2, an E. coli-Bacteroides shuttle vector that contains a transfer origin that is recognized by R751.     

Cooperative nest defence in red-winged blackbirds: reciprocal altruism,kinship or by-product mutualism?

Male red-winged blackbirds (Agelaius phoeniceus) often cooperate with their neighbours in defending nests against predators. Some studies have suggested that this is an example of by-product mutualism, whereas others have suggested the possibility of reciprocal altruism. No study has addressed the possibility of kin-selected cooperation in nest defence in this species. Reciprocal altruism, kin selection and by-product mutualism are not mutually exclusive alternatives, but few studies of territorial neighbours have tested for multiple mechanisms simultaneously. We test for these three possibilities in a population of red-winged blackbirds. We used simulated defections to test for reciprocal altruism. We used analysis of microsatellite loci to test for kin selection between adult male neighbours. We also used microsatellite loci to test for by-product mutualism resulting from nest defence of offspring sired on neighbouring territories. We found that male red-winged blackbirds cooperate in nest defence primarily as a form of reciprocal altruism. Experimental males reduced their level of nest defence relative to controls following simulated defection by a neighbour. In contrast to some earlier studies, we found no evidence for by-product mutualism: males did not defend nests where they had sired extra-pair offspring. We also found no evidence for kin selection: males were no more cooperative with more closely related neighbours. Considered alongside the results from other studies, our study suggests that mechanisms stabilizing cooperation in red-winged blackbirds may vary among populations.     

Response of Reticulitermes spp. (Isoptera: Rhinotermitidae) in northern California to baiting with hexaflumuron with sentricon termite colony elimination system

Colonies of Reticulitermes spp. were baited with prototype and commercial Sentricon stations (Dow AgroSciences LLC, Indianapolis, IN) to test the efficacy of hexaflumuron in different concentrations and bait matrices and to document reinvasion of the foraging territories vacated by eliminated colonies. Seven colonies of Reticuliternes spp. from two sites were characterized with cuticular hydrocarbon analyses and mark-release-recapture and agonistic behavioral studies. Three colonies were observed as controls and four colonies were baited. When a connection between the bait station and the monitoring station could not be confirmed by mark-release-recapture studies, the results of the baiting were equivocal. The monitoring stations of a colony at our wildland site were devoid of termites 406 d after baiting with one Sentricon station, but became reoccupied with the same species of termites approximately 6 mo after baiting. A colony at the residential site was baited with 0.5% hexaflumuron in the Recurit II bait matrix; 60 d later termites were absent from all monitoring stations. These monitoring stations remained unoccupied for > or = 18 mo. Foraging Reticulitermes spp. appeared in three of the seven monitoring stations 18, 24, and 36 mo after baiting, respectively. Using cuticular hydrocarbon analyses and agonistic behavior studies, we determined that the Reticulitermes spp. occupying these monitoring stations were from three different colonies; none were members of the original colony destroyed by baiting. Another colony at the residential site was baited using a noncommercial, experimental bait; 52 d later termites were absent from all monitoring stations. The monitoring stations remained unoccupied for > or = 9 mo. A different Reticulitermes sp. colony invaded one monitoring station 9 mo after baiting.     

Surplus nest boxes and the potential for polygyny affect clutch size and offspring sex ratio in house wrens

Females of many species can gain benefits from being choosy about their mates and even exhibit context-dependent investment in reproduction in response to the quality of their breeding situation. Here, we show that if a male house wren is provided with surplus nest boxes in his territory, his mate lays a larger clutch with a significantly higher proportion of sons. This response to a territory characteristic directly associated with male competitive ability, and ultimately to male reproductive success, suggests that male competition over access to high-quality territories with surplus nest boxes (i.e. those able to support polygyny) may influence female reproductive investment decisions. The results of this study have interesting implications, particularly considering the important role that studies of cavity nesting birds utilizing nest boxes have played in advancing our understanding of behaviour, ecology and evolution.     

A novel interaction of CLN3 with nonmuscle myosin-IIB and defects in cell motility of Cln3 cells

Juvenile neuronal ceroid lipofuscinosis (JNCL) is a pediatric lysosomal storage disorder characterized by accumulation of autofluorescent storage material and neurodegeneration, which result from mutations in CLN3. The function of CLN3, a lysosomal membrane protein, is currently unknown. We report that CLN3 interacts with cytoskeleton-associated nonmuscle myosin-IIB. Both CLN3 and myosin-IIB are ubiquitously expressed, yet mutations in either produce dramatic consequences in the CNS such as neurodegeneration in JNCL patients and Cln3^−/− mouse models, or developmental deficiencies in Myh10^−/− mice, respectively. A scratch assay revealed a migration defect associated with Cln3^−/− cells. Inhibition of nonmuscle myosin-II with blebbistatin in WT cells resulted in a phenotype that mimics the Cln3^−/− migration defect. Moreover, inhibiting lysosome function by treating cells with chloroquine exacerbated the migration defect in Cln3^−/−. Cln3^−/− cells traversing a transwell filter under gradient trophic factor conditions displayed altered migration, further linking lysosomal function and cell migration. The myosin-IIB distribution in Cln3^−/− cells is elongated, indicating a cytoskeleton defect caused by the loss of CLN3. In summary, cells lacking CLN3 have defects that suggest altered myosin-IIB activity, supporting a functional and physical interaction between CLN3 and myosin-IIB. We propose that the migration defect in Cln3^−/− results, in part, from the loss of the CLN3–myosin-IIB interaction.     

A standard protocol for documenting modern and fossil ichnological data

The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming commonplace in the wider palaeontological field. A standard protocol is required to ensure that data is recorded, presented and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means) and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false‐colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers (i.e. in an open format). If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers.