ZINBA integrates local covariates with DNA-seq data to identify broad and narrow regions of enrichment,even within amplified genomic regions

ZINBA (Zero-Inflated Negative Binomial Algorithm) identifies genomic regions enriched in a variety of ChIP-seq and related next-generation sequencing experiments (DNA-seq), calling both broad and narrow modes of enrichment across a range of signal-to-noise ratios. ZINBA models and accounts for factors that co-vary with background or experimental signal, such as G/C content, and identifies enrichment in genomes with complex local copy number variations. ZINBA provides a single unified framework for analyzing DNA-seq experiments in challenging genomic contexts.     

Infection pressure of human alveolar echinococcosis due to village and small town foxes (<Emphasis Type="Italic">Vuples vulpes</Emphasis>) living in close proximity to residents

This study investigated the epidemiological and ecological factors to assess the infection pressure of alveolar echinococcosis to human which are living in villages and small towns. Foxes and fox faeces were examined for Echinococcus multilocularis and foxes were observed by radio telemetry in Upper Bavaria, Germany. Forty-three percent of the village foxes (n = 65) had been infected with E. multilocularis. This prevalence rate did not differ significantly from the prevalence among rural foxes, which was 39% (n = 33; χ ² = 0.12, df = 1, p = 0.727) determined by the intestinal scraping technique. PCR analyses of fox faeces showed a higher infection rate of 35% (n = 26) among rural foxes than among foxes in villages and small towns (26%, n = 69; χ ² = 0.68, df = 1, p = 0.411). One quarter of the fox faecal samples come from private gardens of residents. The radio-tracking study on 17 foxes showed that foxes preferred the built-up area and grassland outside the villages. Village foxes concentrated their activity within a range of 500 m around the settlement. Sixty-four percent of all bearings for radio-tracked foxes showed positions in areas outside the town, and 36% of bearings were within the settlement. Village foxes, which are infected with E. multilocularis, are able to carry the parasite continuously into settlements and fox faeces present an immediate source of infection to humans, especially within their gardens. Therefore, foxes are responsible for environmental E. multilocularis egg contamination in the vicinity of humans, leading to an infection risk to inhabitants of villages and small towns.     

Estrogen and Progestogen Correlates of the Structure of Female Copulation Calls in Semi-Free-Ranging Barbary Macaques (<Emphasis Type="BoldItalic">Macaca sylvanus</Emphasis>)

Females of many Old World primates produce conspicuous vocalizations in combination with copulations. Indirect evidence exists that in Barbary macaques (Macaca sylvanus), the structure of these copulation calls is related to changes in reproductive hormone levels. However, the structure of these calls does not vary significantly around the timing of ovulation when estrogen and progestogen levels show marked changes. We here aimed to clarify this paradox by investigating how the steroid hormones estrogen and progesterone are related to changes in the acoustic structure of copulation calls. We collected data on semi-free-ranging Barbary macaques in Gibraltar and at La Forêt des Singes in Rocamadour, France. We determined estrogen and progestogen concentrations from fecal samples and combined them with a fine-grained structural analysis of female copulation calls (N = 775 calls of 11 females). Our analysis indicates a time lag of 3 d between changes in fecal hormone levels, adjusted for the excretion lag time, and in the acoustic structure of copulation calls. Specifically, we found that estrogen increased the duration and frequency of the calls, whereas progestogen had an antagonistic effect. Importantly, however, variation in acoustic variables did not track short-term changes such as the peak in estrogen occurring around the timing of ovulation. Taken together, our results help to explain why female Barbary macaque copulation calls are related to changes in hormone levels but fail to indicate the fertile phase.     

Response of ‘Clausellina’ Satsuma mandarin to 3,5,6-trichloro-2-pirydiloxyacetic acid and fruitlet abscission

The application of the synthetic auxin 3,5,6-trichloro-2-piridyloxyacetic acid (3,5,6-TPA) isopropyl ester at the onset of cell enlargement stage, significantly thinned fruitlets in ‘Clausellina’ Satsuma mandarin. The magnitude of the response was related to the concentration applied, increasing the percentage of abscised fruit with higher concentrations, which was up to 70% at 25 mg l⁻¹. The magnitude of the response also depended on the organ subject to treatment, abscission being greater when applied to the leaves rather than to fruit. Results suggest that a photosynthetic disorder was responsible for a reduction in fruit growth rate, triggering abscission mechanisms producing ethylene and abscission.     

Ecosystem respiration depends strongly on photosynthesis in a temperate heath

We measured net ecosystem CO₂ flux (F _n) and ecosystem respiration (R _E), and estimated gross ecosystem photosynthesis (P _g) by difference, for two years in a temperate heath ecosystem using a chamber method. The exchange rates of carbon were high and of similar magnitude as for productive forest ecosystems with a net ecosystem carbon gain during the second year of 293 ± 11 g C m⁻² year⁻¹ showing that the carbon sink strength of heather-dominated ecosystems may be considerable when C. vulgaris is in the building phase of its life cycle. The estimated gross ecosystem photosynthesis and ecosystem respiration from October to March was 22% and 30% of annual flux, respectively, suggesting that both cold-season carbon gain and loss were important in the annual carbon cycle of the ecosystem. Model fit of R _E of a classic, first-order exponential equation related to temperature (second year; R ² = 0.65) was improved when the P _g rate was incorporated into the model (second year; R ² = 0.79), suggesting that daytime R _E increased with increasing photosynthesis. Furthermore, the temperature sensitivity of R _E decreased from apparent Q ₁₀ values of 3.3 to 3.9 by the classic equation to a more realistic Q ₁₀ of 2.5 by the modified model. The model introduces R _photo, which describes the part of respiration being tightly coupled to the photosynthetic rate. It makes up 5% of the assimilated carbon dioxide flux at 0°C and 35% at 20°C implying a high sensitivity of respiration to photosynthesis during summer. The simple model provides an easily applied, non-intrusive tool for investigating seasonal trends in the relationship between ecosystem carbon sequestration and respiration.     

Sample size and sampling error in geometric morphometric studies of size and shape

Geometric morphometric studies are increasingly becoming common in systematics and palaeontology. The samples in such studies are often small, due to the paucity of material available for analysis. However, very few studies have tried to assess the impact of sampling error on analytical results. Here, this issue is addressed empirically using repeated randomized selection experiments to build progressively smaller samples from an original dataset of ∼400 vervet monkey (Cercopithecus aethiops) skulls. Size and shape parameters (including mean size and shape, size and shape variances, angles of allometric trajectories) that are commonly used in geometric morphometric studies, are estimated first in the original sample and then in the random subsamples. Estimates are then compared to give an indication of what is the minimum desirable sample size for each parameter. Mean size, standard deviation of size and variance of shape are found to be fairly accurate even in relatively small samples. In contrast, mean shapes and angles between static allometric trajectories are strongly affected by sampling error. If confirmed in other groups, our findings may have substantial implications for studies of morphological variation in present and fossil species. By performing rarefaction analyses like those presented in our study, morphometricians can be easily provided with important clues on how a simple but crucial factor like sample size can alter results of their studies.     

The role of nurse plants in the establishment of shrub seedlings in the semi-arid subtropical Andes

In the nurse plant syndrome, or nurse association, seedlings (beneficiaries) are associated with adult shrubs/trees (benefactors). This phenomenon has been documented in several regions of the planet. Abiotic stress amelioration (one mechanism of facilitation) is one of the causes of this association. Most of the studies addressing the nurse syndrome have been conducted on spatial scales of a few hectares and have focused on only one or a few species. Moreover, there is an almost complete lack of studies addressing the incidence and characteristics of the nurse phenomenon in the arid Andes of South America. We undertook a first approximation to the study of facilitation in these ecosystems. The study was conducted at local and regional scales and involved the assessment of the spatial distribution of juveniles (seedlings and saplings) of 51 populations of 16 shrub and 12 cactus species in relation to shrub cover at 20 localities of the Prepuna (subtropical Andes of Bolivia and Argentina, 20–26°S). In terms of spatial distribution, the juveniles of most of the populations of shrubs studied were distributed both under the shrubs and in open spaces, thereby showing an apparent indifference to microhabitat. Globose and opuntioid cacti were preferentially distributed below the canopies of shrubs and were usually more associated with the dominant shrub species, which stood out as better potential nurses. The pattern was consistent throughout the region, including the more mesic and arid localities. The fact that Prepuna woody species are capable of establishing in open spaces would confer this region a greater resilience. Our findings further suggest that community dynamics in arid and semi-arid environments are more variable than previously thought.