Population dynamics of the African elephant (Loxodonta africana)

Recent studies on elephant populations from East Africa and from Zambia have suggested that as population density increases, so does the mean age at puberty and the mean calving interval. At the same time there is also an increase in the proportion of old females that are reproductively inactive. By constructing elephant population models, it is possible to investigate the extent to which these "homeostatic mechanisms" will regulate an elephant population. The models indicate that a change in the duration of the calving interval is more important as a population regulating mechanism than a change in the age at puberty, and that the proportion of old reproductively inactive females is of little significance. The importance of neonatal mortality in controlling population growth is emphasised by the models, and they also show that an annual population increase of 4% would be close to the maximum value.     

Velocity-based movement modeling for individual and population level inference

Understanding animal movement and resource selection provides important information about the ecology of the animal, but an animal's movement and behavior are not typically constant in time. We present a velocity-based approach for modeling animal movement in space and time that allows for temporal heterogeneity in an animal's response to the environment, allows for temporal irregularity in telemetry data, and accounts for the uncertainty in the location information. Population-level inference on movement patterns and resource selection can then be made through cluster analysis of the parameters related to movement and behavior. We illustrate this approach through a study of northern fur seal (Callorhinus ursinus) movement in the Bering Sea, Alaska, USA. Results show sex differentiation, with female northern fur seals exhibiting stronger response to environmental variables.     

Genome sequence of the emerging pathogen Aeromonas caviae

Aeromonas caviae is a Gram-negative, motile and rod-shaped facultative anaerobe that is increasingly being recognized as a cause of diarrhea in children. Here we present the first genome sequence of an A. caviae strain that was isolated as the sole pathogen from a child with profuse diarrhea.     

Control of the straw itch mite (Acari: Pyemotidae) with sulfur in an insect rearing facility.

The ectoparasitic mite Pyemotes tritici (Lagrèze-Fossat & Montané) (Acari: Pyemotidae) caused paralysis and reduced longevity in eucalyptus longhorned borer, Phoracantha semipunctata F., under laboratory rearing conditions. Application of dusting sulfur to logs that contained pupating borers greatly reduced densities of mites on emerging adult beetles and increased beetle survivorship. Uniform application to all logs in a glasshouse effectively eradicated the mite infestation. A bioassay showed that sulfur may physically impede the dispersal of immature mites by adhering to the cuticle, but sulfur vapor did not act as a toxin.     

Late immature mortality is the major influence on reproductive success of African black beetle, Heteronychus arator (Fabricius) (Coleoptera: Scarabaeidae), in a Mediterranean-climate region of Australia

In field and laboratory studies, mortality of African black beetle, Heteronychus arator, in the winter-rainfall, Mediterranean-type climate region of south-western Australia was higher in the late immature stages during summer than in the early immature stages that occur during spring, a contrast to summer-rainfall climatic regions. Greatest mortality occurred around the pupal stage in contrasting soil types, despite drying differences in summer and supplementary watering in some plots. Sampling of natural populations confirmed experimental results that mortality in late immature stages is the major factor limiting H. arator populations under a Mediterranean-type climate. Inter-generation increase in H. arator abundance was uncommon, explaining the consistent abundance typically observed between years in south-western Australia. Random dispersal of newly emerged adults in autumn was inferred to restore uniformity in adult abundance between areas of varying favourability for immature survival.     

Indole-3-carbinol and its N-alkoxy derivatives preferentially target ERα-positive breast cancer cells

Indole-3-carbinol (I3C) is a natural anti-carcinogenic compound found at high concentrations in Brassica vegetables. I3C was recently reported to inhibit neutrophil elastase (NE) activity, while consequently limiting the proteolytic processing of full length cyclin E into pro-tumorigenic low molecular weight cyclin E (LMW-E). In this study, we hypothesized that inhibition of NE activity and resultant LMW-E generation is critical to the anti-tumor effects of I3C. LMW-E was predominately expressed by ERα-negative breast cancer cell lines. However, ERα-positive cell lines demonstrated the greatest sensitivity to the anti-tumor effects of I3C and its more potent N-alkoxy derivatives. We found that I3C was incapable of inhibiting NE activity or the generation of LMW-E. Therefore, this pathway did not contribute to the anti-tumor activity of I3C. Gene expression analyzes identified ligand-activated aryl hydrocarbon receptor (AhR), which mediated sensitivity to the anti-tumor effects of I3C in ERα-positive MCF-7 cells. In this model system, the reactive oxygen species (ROS)-induced upregulation of ATF-3 and pro-apoptotic BH3-only proteins (e.g. NOXA) contributed to the sensitivity of ERα-positive breast cancer cells to the anti-tumor effects of I3C. Overexpression of ERα in MDA-MB-231 cells, which normally lack ERα expression, increased sensitivity to the anti-tumor effects of I3C, demonstrating a direct role for ERα in mediating the sensitivity of breast cancer cell lines to I3C. Our results suggest that ERα signaling amplified the pro-apoptotic effect of I3C-induced AhR signaling in luminal breast cancer cell lines, which was mediated in part through oxidative stress induced upregulation of ATF-3 and downstream BH3-only proteins.     

New Year’s Res-Illusions: Food Shopping in the New Year Competes with Healthy Intentions

Objective

How do the holidays – and the possible New Year’s resolutions that follow – influence a household’s purchase patterns of healthier foods versus less healthy foods? This has important implications for both holiday food shopping and post-holiday shopping.

Methods

207 households were recruited to participate in a randomized-controlled trial conducted at two regional-grocery chain locations in upstate New York. Item-level transaction records were tracked over a seven-month period (July 2010 to March 2011). The cooperating grocer’s proprietary nutrient-rating system was used to designate “healthy,” and “less healthy” items. Calorie data were extracted from online nutritional databases. Expenditures and calories purchased for the holiday period (Thanksgiving-New Year’s), and the post-holiday period (New Year’s-March), were compared to baseline (July-Thanksgiving) amounts.

Results

During the holiday season, household food expenditures increased 15% compared to baseline ($105.74 to $121.83; p<0.001), with 75% of additional expenditures accounted for by less-healthy items. Consistent with what one would expect from New Year’s resolutions, sales of healthy foods increased 29.4% ($13.24/week) after the holiday season compared to baseline, and 18.9% ($9.26/week) compared to the holiday period. Unfortunately, sales of less-healthy foods remained at holiday levels ($72.85/week holiday period vs. $72.52/week post-holiday). Calories purchased each week increased 9.3% (450 calories per serving/week) after the New Year compared to the holiday period, and increased 20.2% (890 calories per serving/week) compared to baseline.

Conclusions

Despite resolutions to eat more healthfully after New Year’s, consumers may adjust to a new “status quo” of increased less-healthy food purchasing during the holidays, and dubiously fulfill their New Year’s resolutions by spending more on healthy foods. Encouraging consumers to substitute healthy items for less-healthy items may be one way for practitioners and public health officials to help consumers fulfill New Year’s resolutions, and reverse holiday weight gain.     

Contact Pheromones as Mate Recognition Cues of Four Species of Longhorned Beetles (Coleoptera: Cerambycidae)

We tested the hypothesis that contact phermones mediate mate recognition for four species of longhorned beetles, Neoclytus mucronatus mucronatus (F.), Megacyllene caryae (Gahan), Megacyllene robiniae (Forster), and Plectrodera scalator (F.). All tested males of all four species attempted to mate with females only after contacting them with their antennae. From 66.7 to 80% of tested males attempted to mate with hexane-extracted dead females treated with 0.1–1.0 female equivalents of conspecific female extracts, confirming that nonpolar compounds on the cuticle of females are essential for mate recognition in all four species. These findings are further evidence of the critical role of contact pheromones in mating systems of longhorned beetles.