The persistent microbicidal effect in water exposed to the corona discharge

This article describes and particularly explains a new phenomenon of persistent microbicidal effect of water previously exposed to the low-temperature plasma, which cannot be attributed to the acidification only. The direct microbicidal action of plasma is well documented, being mediated by number of reactive particles with a short lifetime. However, we observed the microbicidal effect also in exposed water stored for a month, where it must be mediated by stable particles. In water and in phosphate-buffered saline, the formation of NO_x and corresponding acids, H₂O₂ and O₃ was confirmed after exposition to the low-temperature plasma generated in air by DC negative glow corona and positive streamer discharge. The time course of acidification, H₂O₂ and O₃ formation were deremined. Except uncertain traces of HCN, SIFT-MS analysis of exposed liquids reveals no additional reactive compounds. The microbicidal effect persists almost unchanged during 4 weeks of storage, although O₃ completely and H₂O₂ almost disappears. Staphylococcus epidermidis and Escherichia coli were inactivated within 10 min of incubation in exposed liquids, Candida albicans needs at least 1 h. The solutions prepared by artificial mixing of reactive compounds mimic the action of exposed water, but in lesser extent. The acid milieu is the main cause of the microbicidal effect, but the possibility of still unidentified additional compound remains open.     

Replicating rather than nonreplicating adenovirus-human immunodeficiency virus recombinant vaccines are better at eliciting potent cellular immunity and priming high-titer antibodies

A major challenge in combating the human immunodeficiency virus (HIV) epidemic is the development of vaccines capable of inducing potent, persistent cellular immunity and broadly reactive neutralizing antibody responses to HIV type 1 (HIV-1). We report here the results of a preclinical trial using the chimpanzee model to investigate a combination vaccine strategy involving sequential priming immunizations with different serotypes of adenovirus (Ad)/HIV-1(MN)env/rev recombinants and boosting with an HIV envelope subunit protein, oligomeric HIV(SF162) gp140deltaV2. The immunogenicities of replicating and nonreplicating Ad/HIV-1(MN)env/rev recombinants were compared. Replicating Ad/HIV recombinants were better at eliciting HIV-specific cellular immune responses and better at priming humoral immunity against HIV than nonreplicating Ad-HIV recombinants carrying the same gene insert. Enhanced cellular immunity was manifested by a greater frequency of HIV envelope-specific gamma interferon-secreting peripheral blood lymphocytes and better priming of T-cell proliferative responses. Enhanced humoral immunity was seen in higher anti-envelope binding and neutralizing antibody titers and better induction of antibody-dependent cellular cytotoxicity. More animals primed with replicating Ad recombinants mounted neutralizing antibodies against heterologous R5 viruses after one or two booster immunizations with the mismatched oligomeric HIV-1(SF162) gp140deltaV2 protein. These results support continued development of the replicating Ad-HIV recombinant vaccine approach and suggest that the use of replicating vectors for other vaccines may prove fruitful.     

<Emphasis Type="Italic">Anacamptis</Emphasis> versus <Emphasis Type="Italic">Orchis</Emphasis> (Orchidaceae): seed micromorphology and its taxonomic significance

Seed micromorphology of 24 taxa of the genera Anacamptis and Orchis was examined under light and scanning electron microscopy. Seed qualitative characters appear very useful at the supraspecific level in the subtribe Orchidinae. Based on our observations, the sculpturing of the periclinal walls of the medial testa cells, the seed shape and several features of the anticlinal walls of the apical cells showed variability between the studied taxa, with special relevance of the first character. According to this factor, we found one type of seed for Anacamptis and two for Orchis. The taxonomic value of seed coat characters is compared with the last taxonomic proposals for the genera Anacamptis and Orchis.     

Modulation of auxin signalling through DIAGETROPICA and ENTIRE differentially affects tomato plant growth via changes in photosynthetic and mitochondrial metabolism

Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher V_cmax and J_max coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes.     

Masting uncoupling: mast seeding does not follow all mast flowering episodes in a dioecious juniper tree

Evolutionary selective forces, like predator satiation and pollination efficiency, are acknowledged to be major causes of masting (the variable, periodic and synchronic production of seeds in a population). However, a number of recent studies indicate that resources might also play an important role on shaping masting patterns. Dioecious masting species offer a privileged framework to study the role of resources on masting variation, since male and female plants often experience different reproductive costs and selective pressures. We followed masting and reproductive investment (RI) of the dioecious tree Juniperus thurifera in two populations along 10 years and studied the different response of males and females to experimentally increased water and nutrient availability in a third population. Juniperus thurifera females invested in reproduction three times more resources than males. Such disparity generated different resource‐use strategies in male and female trees. Tree‐ring growth and water use efficiency (WUE) confirmed that sexes differed in their resource investment temporal pattern, with males using current resources for reproduction and females using resources accumulated during longer periods. Watered and fertilized female trees presented significantly higher flowering reproductive investments than males and experienced an extraordinary mast‐flowering event. However, seeding RI and mast seeding were not affected by the treatment. This suggests that although resource availability affects the reproductive output of this species, there are other major forces regulating masting on J. thurifera. During 10 years, J. thurifera male and female trees presented high and low flowering years more or less synchronously. However, not all mast flowering episodes resulted in mast seeding, leading to masting uncoupling between flowering and seeding. Since flowering costs represent only 1% of females’ total reproductive investments, masting uncoupling could be a beneficial bet‐hedging strategy to maximize reproductive output in spite of unpredictable catastrophic events.     

Climate change, humans, and the extinction of the woolly mammoth

Woolly mammoths inhabited Eurasia and North America from late Middle Pleistocene (300 ky BP [300,000 years before present]), surviving through different climatic cycles until they vanished in the Holocene (3.6 ky BP). The debate about why the Late Quaternary extinctions occurred has centred upon environmental and human-induced effects, or a combination of both. However, testing these two hypotheses—climatic and anthropogenic—has been hampered by the difficulty of generating quantitative estimates of the relationship between the contraction of the mammoth's geographical range and each of the two hypotheses. We combined climate envelope models and a population model with explicit treatment of woolly mammoth–human interactions to measure the extent to which a combination of climate changes and increased human pressures might have led to the extinction of the species in Eurasia. Climate conditions for woolly mammoths were measured across different time periods: 126 ky BP, 42 ky BP, 30 ky BP, 21 ky BP, and 6 ky BP. We show that suitable climate conditions for the mammoth reduced drastically between the Late Pleistocene and the Holocene, and 90% of its geographical range disappeared between 42 ky BP and 6 ky BP, with the remaining suitable areas in the mid-Holocene being mainly restricted to Arctic Siberia, which is where the latest records of woolly mammoths in continental Asia have been found. Results of the population models also show that the collapse of the climatic niche of the mammoth caused a significant drop in their population size, making woolly mammoths more vulnerable to the increasing hunting pressure from human populations. The coincidence of the disappearance of climatically suitable areas for woolly mammoths and the increase in anthropogenic impacts in the Holocene, the coup de grâce, likely set the place and time for the extinction of the woolly mammoth.     

Growth and derived life-history characteristics of the Brazilian electric ray Narcine brasiliensis

The majority of batoids are listed as Threatened (20.4%) or Data Deficient (41%) by the IUCN Red List. A key challenge to assessing Data-Deficient species is obtaining estimates of key life-history characteristics. Here, a Bayesian approach was used to estimate derived life-history characteristics from a growth model applied to the Data-Deficient Brazilian electric ray Narcine brasiliensis. The age of 170 specimens (107 females, 63 males) was estimated from vertebral centra, and total length, disc width, total weight and birth size were used in a joint estimation of sex-specific length-weight models and two-dimensional von Bertalanffy growth models. Estimates of age at length zero, age at maturity, longevity and mortality at age were derived simultaneously. The Bayesian joint modelling approach was robust to small sample sizes by adding a likelihood to constrain L₀ and sharing parameters, such as Brody growth coefficient between length measurements. The median growth parameter estimates were a shared L₀ = 38.8 mm, female L_∞ = 515 mm, 𝑘 = 0.125 and male L_∞ = 387 mm, 𝑘 = 0.194. Age at maturity was estimated to be 7.40–7.49 years for females and 4.45–4.47 years for males, whereas longevity was 22.5–22.6 years for females and 14.2 years for males depending on length measurement. Age-1 natural mortality was estimated to be 0.199–0.207 for females and 0.211–0.213 for males. The derived life-history characteristics indicate N. brasiliensis is earlier maturing, but slower growing relative to other Torpediniformes. These characteristics along with the species’ endemism to southern Brazil and high by-catch rates indicate that one of the IUCN Red List threatened categories may be more appropriate for the currently Data-Deficient status. The Bayesian approach used for N. brasiliensis can prove useful for utilizing limited age-growth data in other Data-Deficient batoid species to inform necessary life characteristics for conservation and management.     

Using Satellite Tracking and Isotopic Information to Characterize the Impact of South American Sea Lions on Salmonid Aquaculture in Southern Chile

Apex marine predators alter their foraging behavior in response to spatial and/or seasonal changes in natural prey distribution and abundance. However, few studies have identified the impacts of aquaculture that represents a spatially and temporally predictable and abundant resource on their foraging behavior. Using satellite telemetry and stable isotope analysis we examined the degree of spatial overlap between the South American sea lion (SASL) and salmon farms, and quantify the amount of native prey versus farmed salmonids in SASL diets. We instrumented eight SASL individuals with SRDL-GPS tags. Vibrissae, hair and skin samples were collected for δ¹³C and δ¹⁵N analyses from five of the tagged individuals and from four males captured in a haul-out located adjacent to salmon farms. Tracking results showed that almost all the foraging areas of SASL are within close proximity to salmon farms. The most important prey for the individuals analyzed was farmed salmonids, with an estimated median (±SD) contribution of 19.7 ± 13.5‰ and 15.3 ± 9.6‰ for hair and skin, respectively. Using vibrissae as a temporal record of diet for each individual, we observed a remarkable switch in diet composition in two SASL, from farmed salmonids to pelagic fishes, which coincided with the decrease of salmon production due to the infectious salmon anemia virus that affected salmon farms in Chile at the end of 2008. Our study demonstrates the usefulness of integrating stable isotope derived dietary data with movement patterns to characterize the impacts of a non-native prey on the foraging ecology of an apex marine predator, providing important applied implications in situations where interactions between aquaculture and wildlife are common.