Differentiation of Clostridium botulinum Serotype A Strains by Multiple-Locus Variable-Number Tandem-Repeat Analysis

Ten variable-number tandem-repeat (VNTR) regions identified within the complete genomic sequence of Clostridium botulinum strain ATCC 3502 were used to characterize 59 C. botulinum strains of the botulism neurotoxin A1 (BoNT/A1) to BoNT/A4 (BoNT/A1-A4) subtypes to determine their ability to discriminate among the serotype A strains. Two strains representing each of the C. botulinum serotypes B to G, including five bivalent strains, and two strains of the closely related species Clostridium sporogenes were also tested. Amplified fragment length polymorphism analyses revealed the genetic diversity among the serotypes and the high degree of similarity among many of the BoNT/A1 strains. The 10 VNTR markers amplified fragments within all of the serotype A strains but were less successful with strains of other serotypes. The composite multiple-locus VNTR analysis of the 59 BoNT/A1-A4 strains and 3 bivalent B strains identified 38 different genotypes. Thirty genotypes were identified among the 53 BoNT/A1 and BoNT/A1(B) strains, demonstrating discrimination below the subtype level. Contaminating DNA within crude toxin preparations of three BoNT/A subtypes (BoNT/A1 to BoNT/A3) also supported amplification of all of the VNTR regions. These markers provide clinical and forensics laboratories with a rapid, highly discriminatory tool to distinguish among C. botulinum BoNT/A1 strains for investigations of botulism outbreaks.     

Thermoregulatory behaviour explains countergradient variation in the upper thermal limit of a rainforest skink

The vulnerability of a terrestrial ectotherm to high environmental temperatures depends on the animal's thermal physiology and thermoregulatory behaviour. These variables – environment, physiology, and behaviour – interact with each other, complicating assessment of species vulnerability to global warming. We previously uncovered a counterintuitive pattern in rainforest sunskinks Lampropholis coggeri: a negative relationship between their critical thermal maximum (CT_max) and the temperature of their environment. Could this result be explained by a three‐way interaction between environment, physiology, and behaviour? Here we find that sunskink thermal preference is correlated positively with CT_max, but, importantly, skinks from hotter environments prefer lower temperatures than conspecifics from cooler environments. In an acclimation experiment, we find that CT_max is plastic and shifts in alignment with acclimation temperature. We also found heritable variation in this trait in a common garden study, but this variation was small relative to the plastic shifts observed in CT_max. Thus, our previous observation of a negative correlation between field CT_max and temperature is explained, at least in part, by the lizard's thermoregulatory behaviour: lizards from hot environments preferentially choose cool microenvironments, and their physiology acclimates to these cooler experienced temperatures. Our results suggest that behavioural adjustments to the environment can produce countergradient variation in physiological traits. More broadly, our work underscores the importance of interactions between environment, behaviour, and physiology in ectotherms. Understanding these interactions will be crucial in assessing vulnerability to climate change.     

Women,mobile phones,and M16s: Contemporary New Guinea highlands warfare

This paper reports upon a series of recent developments in New Guinea highlands warfare. Building upon existing literature highlighting the deep influence of modernity within this context, we draw attention to two particular developments yet to be reported in the literature and which appear to be of special significance. Through an analysis of Aiya warfare, Southern Highlands Province, Papua New Guinea, we document the direct and increasing involvement of women within warfare, as well as the important role played by mobile phones used by warriors to communicate before and during fighting. These two developments are situated in relation to broader shifts currently reshaping Melanesian sociality, namely, the ambivalent and fraught position of women within an emergent PNG society, as well as the rapid diffusion of mobile phone technology throughout the region.     

Climate change, conservation and management: an assessment of the peer-reviewed scientific journal literature

Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change, similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species. Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper our ability to make useful recommendations in a world that is experiencing significant global change.     

Sentenced without trial: reviling and revamping the Resource Dispersion Hypothesis

The resource dispersion hypothesis (RDH) offers a predictive model for how, in heterogeneous environments, some animals may form groups even without any direct benefits from doing so. Revilla (2003) levels a number of criticisms at the RDH, all of which we feel can be easily clarified or resolved (we address them in the order they appear in his critique). We argue that the RDH, despite its long history and despite our own efforts, still lacks convincing evidence to reject it. On the contrary, we see it as having weathered its critics very well. While there is steadily accumulating evidence in support of the RDH, there are very few empirical tests that provide decent evidence against it.     

Demography of the Giant Otter (Pteronura brasiliensis) in Manu National Park,South-Eastern Peru: Implications for Conservation

The giant otter (Pteronura brasiliensis) is an endangered semi-aquatic carnivore of South America. We present findings on the demography of a population inhabiting the floodplain of Manu National Park, south-eastern Peru, arising from 14 annual dry season censuses over a 16 year period. The breeding system of territorial groups, including only a single breeding female with non-reproductive adult ‘helpers’, resulted in a low intrinsic rate of increase (0.03) and a slow recovery from decades of hunting for the pelt trade. This is explained by a combination of factors: (1) physiological traits such as late age at first reproduction and long generation time, (2) a high degree of reproductive skew, (3) small litters produced only once a year, and (4) a 50% mortality between den emergence and age of dispersal, as well as high mortality amongst dispersers (especially males). Female and male giant otters show similar traits with respect to average reproductive life-spans (female 5.4 yrs., male 5.2 yrs.) and average cub productivity (female 6.9, male 6.7 cubs per lifetime); the longest reproductive life spans were 11 and 13 years respectively. Individual reproductive success varied substantially and depended mainly on the duration of dominance tenure in the territory. When breeding females died, the reproductive position in the group was usually occupied by sisters or daughters (n = 11), with immigrant male partners. Male philopatry was not observed. The vulnerability of the Manu giant otter population to anthropogenic disturbance emphasises the importance of effective protection of core lake habitats in particular. Riverine forests are the most endangered ecosystem in the Department of Madre de Dios due to the concentration of gold mining, logging and agricultural activities in floodplains, highlighting the need for a giant otter habitat conservation corridor along the Madre de Dios River.     

Finding Near-Optimal Groups of Epidemic Spreaders in a Complex Network

In this paper, we present algorithms to find near-optimal sets of epidemic spreaders in complex networks. We extend the notion of local-centrality, a centrality measure previously shown to correspond with a node''s ability to spread an epidemic, to sets of nodes by introducing combinatorial local centrality. Though we prove that finding a set of nodes that maximizes this new measure is NP-hard, good approximations are available. We show that a strictly greedy approach obtains the best approximation ratio unless P = NP and then formulate a modified version of this approach that leverages qualities of the network to achieve a faster runtime while maintaining this theoretical guarantee. We perform an experimental evaluation on samples from several different network structures which demonstrate that our algorithm maximizes combinatorial local centrality and consistently chooses the most effective set of nodes to spread infection under the SIR model, relative to selecting the top nodes using many common centrality measures. We also demonstrate that the optimized algorithm we develop scales effectively.