Exposure of black-legged kittiwakes to Lyme disease spirochetes: dynamics of the immune status of adult hosts and effects on their survival

1. Despite a growing interest in wildlife disease ecology, there is a surprising lack of knowledge about the exposure dynamics of individual animals to naturally circulating infectious agents and the impact of such agents on host life-history traits. 2. The exploration of these questions requires detailed longitudinal data on individual animals that can be captured multiple times during their life but also requires being able to account for several sources of uncertainty, notably the partial observation or recapture of individuals at each sampling occasion. 3. We use a multi-year dataset to (i) assess the potential effect of exposure to the tick-borne agent of Lyme disease, Borrelia burgdorferi sensu lato (Bbsl), on adult apparent survival for one of its natural long-lived hosts, the Black-legged kittiwake (Rissa tridactyla), and (ii) investigate the temporal dynamics of individual immunological status in kittiwakes to infer the rate of new exposure and the persistence of the immune response. Using a multi-event modelling approach, potential uncertainties arising from partial observations were explicitly taken into account. 4. The potential impact of Bbsl on kittiwake survival was also evaluated via an experimental approach: the apparent survival of a group of breeding birds treated with an antibiotic was compared with that of a control group. 5. No impact of exposure to Bbsl was detected on adult survival in kittiwakes, in either observational or experimental data. 6. An annual seroconversion rate (from negative to positive) of 1·5% was estimated, but once an individual became seropositive, it remained so with a probability of 1, suggesting that detectable levels of anti-Bbsl antibodies persist for multiple years. 7. These results, in combination with knowledge on patterns of exposure to the tick vector of Bbsl, provide important information for understanding the spatio-temporal nature of the interaction between this host and several of its parasites. Furthermore, our analyses highlight the utility of capture-mark-recapture approaches handling state uncertainty for disease ecology studies.     

An evaluation of aerobic and anaerobic sludges as start-up material for microbial fuel cell systems

The operation of microbial fuel cells (MFCs) seeded with the same quantities of aerobic or anaerobic sludge has been compared. The two sludges consisted of mixed cultures obtained from the aerobic reactor and anaerobic digester, respectively, of a municipal Wastewater Treatment Plant (WWTP). Both the sludges were diluted with their sedimentation supernatant to avoid modifying their metabolism. The results show that the type of sludge has a major impact on the performance of the system. Seeding an MFC with anaerobic acclimated sludge leads to a more rapid start-up of electricity production and the absence of a lag period. In the MFC seeded with anaerobic sludge, the steady-state operation conditions were achieved in less than 10 days, while in the aerobic sludge-seeded MFC more than 20 days were necessary to achieve this regime. The anaerobic sludge also led to better performance of the MFC. Thus, maximum power densities above 300mWm(-2) were obtained for such systems (i.e. two times higher than that achieved with the aerobic sludge-seeded MFC in the same setup). This better performance is a direct consequence of the greater availability of Chemical Oxygen Demand (COD) in anaerobic sludge. However, the performance is not a consequence of the coulombic efficiency in the use of the COD to produce electricity because the aerobic sludge-seeded MFC doubles this figure with respect to the anaerobic sludge-seeded system.     

Performance of Chlorella sorokiniana under simulated extreme winter conditions

High annual microalgae productivities can only be achieved if solar light is efficiently used through the different seasons. During winter the productivity is low because of the light and temperature conditions. The productivity and photosynthetic efficiency of Chlorella sorokiniana were assessed under the worst-case scenario found during winter time in Huelva, south of Spain. The maximum light intensity (800?μmol photons m^-2 s^-1) and temperature (20°C) during winter were simulated in a lab-scale photobioreactor with a short light-path of 14?mm. Chemostat conditions were applied and the results were compared with a temperature-controlled situation at 38°C (optimal growth temperature for C. sorokiniana). When temperature was optimal the highest productivity was found at a dilution rate of 0.18 h^-1 (P _v?=?0.28?g Kg^-1 h^-1), and the biomass yield on light energy was high (Y _x,E?=?1.2?g?mol^-1 photons supplied). However, at suboptimal temperature, the specific growth rate of C. sorokiniana was surprisingly low, not being able to support continuous operation at a dilution rate higher than 0.02 h^-1. The slow metabolism under suboptimal temperature resulted in a decline of the light energy requirements of the cells. Consequently, the maximum winter irradiance was experienced as excessive, leading to a low photosynthetic efficiency and productivity (Y _x,E?=?0.5?g mol^-1 photons supplied, P _v?=?0.1?g Kg^-1 h^-1). At suboptimal temperature a higher carotenoid-to-chlorophyll ratio was observed indicating the activation of light-dissipating processes. We conclude that temperature control and/or light dilution during winter time will enhance the productivity.     

Spoligotyping and variable number tandem repeat analysis of Mycobacterium bovis isolates from cattle in Brazil

We performed spoligotyping and 12-mycobacterial interspersed repetitive unit-variable number tandem repeats (MIRU-VNTRs) typing to characterise Mycobacterium bovis isolates collected from tissue samples of bovines with lesions suggestive for tuberculosis during slaughter inspection procedures in abattoirs in Brazil. High-quality genotypes were obtained with both procedures for 61 isolates that were obtained from 185 bovine tissue samples and all of these isolates were identified as M. bovis by conventional identification procedures. On the basis of the spoligotyping, 53 isolates were grouped into nine clusters and the remaining eight isolates were unique types, resulting in 17 spoligotypes. The majority of the Brazilian M. bovis isolates displayed spoligotype patterns that have been previously observed in strains isolated from cattle in other countries. MIRU-VNTR typing produced 16 distinct genotypes, with 53 isolates forming eight of the groups, and individual isolates with unique VNTR profiles forming the remaining eight groups. The allelic diversity of each VNTR locus was calculated and only two of the 12-MIRU-VNTR loci presented scores with either a moderate (0.4, MIRU16) or high (0.6, MIRU26) discriminatory index (h). Both typing methods produced similar discriminatory indexes (spoligotyping h = 0.85; MIRU-VNTR h = 0.86) and the combination of the two methods increased the h value to 0.94, resulting in 29 distinct patterns. These results confirm that spoligotyping and VNTR analysis are valuable tools for studying the molecular epidemiology of M. bovis infections in Brazil.     

Interacting effects of aromatic plants and female age on nest-dwelling ectoparasites and blood-sucking flies in avian nests

Some avian species incorporate aromatic plants to their nests. The "nest protection hypothesis", which posits that volatile secondary compounds contained in these plants may have antiparasite properties, has not received full support. All previous tests of this hypothesis have only considered effects on nest-dwelling ectoparasites, but not on blood-sucking flies. The "drug hypothesis" posits that aromatic plants may stimulate nestling immune system, development, or condition. We tested these hypotheses experimentally in wild blue tits, Cyanistes caeruleus, a species that adds aromatic plants to their nests. We supplemented aromatic plants to half of a sample of nests, while adding grass to the other half of nests. We quantified abundance of two groups of blood-sucking flies (blackflies and biting midges) at two different stages of the reproductive period, and abundance of three nest-dwelling ectoparasites (fleas, mites, and blowflies). Experimental supplementation of aromatic plants reduced abundance of fleas only in nests of yearling females and not in nests of older females. Blackflies and biting midges were both more numerous in nests of yearling females than in nests of older females. Mass of aromatic plants added by females was negatively related with abundance of fleas in control nests but not in experimental nests supplied with aromatic plants. Mass of plants added by females was also positively related with abundance of blackflies during the nestling stage. Finally, aromatic plants did not affect nestling growth or immune responses. We conclude that several factors such as female experience and their ability to add plants to the nest interact to explain effects of aromatic plants on different parasites.     

Maternal antibody persistence: a neglected life-history trait with implications from albatross conservation to comparative immunology

The evolution of different life-history strategies has been suggested as a major force constraining physiological mechanisms such as immunity. In some long-lived oviparous species, a prolonged persistence of maternal antibodies in offspring could thus be expected in order to protect them over their long growth period. Here, using an intergenerational vaccination design, we show that specific maternal antibodies can display an estimated half-life of 25 days post-hatching in the nestlings of a long-lived bird. This temporal persistence is much longer than previously known for birds and it suggests specific properties in the regulation of IgY immunoglobulin catabolism in such a species. We also show that maternal antibodies in the considered procellariiform species are functional as late as 20 days of age. Using a modelling approach, we highlight that the potential impact of such effects on population viability could be important, notably when using vaccination for conservation. These results have broad implications, from comparative immunology to evolutionary eco-epidemiology and conservation biology.     

Scalable Manufacturing of Human Mesenchymal Stromal Cells in the Vertical‐Wheel Bioreactor System: An Experimental and Economic Approach

Mesenchymal stromal cells (MSC) hold great promise for tissue engineering applications and cell‐based therapies. Large cell doses (>1 × 10⁶ cells kg^?1) and Good Manufacturing Practices (GMP)‐compliant processes are however required for clinical purposes. Here, a serum‐ and xenogeneic‐free (S/XF) microcarrier‐based culture system is established for the expansion of human umbilical cord matrix (UCM)‐ and adipose tissue (AT)‐derived MSC using the Vertical‐Wheel system (PBS‐0.1 MAG; PBS Biotech). UCM and AT MSC are expanded to maximum cell densities of 5.3 ± 0.4 × 10⁵ cell mL^?1 (n = 3) and 3.6 ± 0.7 × 10⁵ cell mL^?1 (n = 3), respectively, after 7 days of culture, while maintaining their identity, according to standard criteria. An economic evaluation of the process transfer from T‐flasks to PBS‐0.1 MAG shows a reduction in the costs associated with the production of a dose for an average 70 kg adult patient (i.e., 70 million cells). Costs decrease from $17.0 K to $11.1 K for UCM MSC and from $21.5 K to $11.1 K for AT MSC, proving that the transition to Vertical‐Wheel reactors provides a cost‐effective alternative for MSC expansion. The present work reports the establishment of a scalable and cost‐effective culture platform for the manufacturing of UCM and AT MSC in a S/XF microcarrier‐based system.     

Tolerance to waterlogging in young Euterpe oleracea plants

This study investigated whether gas exchange and the present content of antioxidant compounds can contribute to the survival of Euterpe oleracea plants in environments of frequent waterlogging. A factorial randomised, experimental design included two distinct water conditions (waterlogging and control) and five evaluation times (0, 6, 12, 18, and 24 d). Gasexchange parameters, leaf temperature, electrolyte leakage, and contents of antioxidant compounds were measured. Waterlogging did not promote significant alterations in net photosynthetic rate and transpiration, and stomatal conductance was reduced only after 18 d. Malondialdehyde and glutathione contents did not significantly change during waterlogging. Additionally, electrolyte leakage was significant only after 18 d of waterlogging. Thus, this study revealed that maintenance in gas exchange and antioxidant compounds might contribute to the survival of E. oleracea plants in environments exposed to waterlogging.     

Wild canids,domestic dogs and their pathogens in Southeast Brazil: disease threats for canid conservation

Wild canids are under many pressures, including habitat loss, fragmentation and disease. The current lack of information on the status of wildlife health may hamper conservation efforts in Brazil. In this paper, we examined the prevalence of canine pathogens in 21 free-ranging wild canids, comprising 12 Cerdocyon thous (crab-eating fox), 7 Chrysocyon brachyurus (maned wolf), 2 Lycalopex vetulus (hoary fox), and 70 non-vaccinated domestic dogs from the Serra do Cipó National Park area, Southeast Brazil. For wild canids, seroprevalence of antibodies to canine parvovirus, canine adenovirus, canine coronavirus and Toxoplasma gondii was 100 (21/21), 33 (7/21), 5 (1/19) and 68 (13/19) percent, respectively. Antibodies against canine distemper virus, Neospora caninum or Babesia spp. were not found. We tested domestic dogs for antibodies to canine parvovirus, canine distemper virus and Babesia spp., and seroprevalences were 59 (41/70), 66 (46/70), and 42 (40/70) percent, respectively, with significantly higher prevalence in domestic dogs for CDV (P < 0.001) and Babesia spp. (P = 0.002), and in wild canids for CPV (P < 0.001). We report for the first time evidence of exposure to canine coronavirus in wild hoary foxes, and Platynossomun sp. infection in wild maned wolves. Maned wolves are more exposed to helminths than crab-eating foxes, with a higher prevalence of Trichuridae and Ancylostomidae in the area. The most common ectoparasites were Amblyomma cajennense, A. tigrinum, and Pulex irritans. Such data is useful information on infectious diseases of Brazilian wild canids, revealing pathogens as a threat to wild canids in the area. Control measures are discussed.