Colour and chemical changes on photodegraded beech wood with or without red heartwood

The focus of this study was to investigate the chemical and colour changes occurring at different exposure times on artificially photo-irradiated surfaces of normal and red heartwood in beech in order to understand the mechanisms that cause the changes and to evaluate the possibility of usages of beech not only for energy production purposes. In this sense, surface colour modifications are of crucial importance to define the commercial value of beech wood. The artificial photo-irradiation of the wood samples was performed in a Solar Box, equipped with an ultraviolet filter that cuts off the spectrum at 280 nm. Reflectance spectrophotometry and Fourier transform infrared (FTIR) spectroscopy were used to assess artificial sunlight influence. The experimental data were statistically treated to evaluate their significance. Colour monitoring revealed that wood surface colour undergoes an important variation due to photo-irradiation, occurring within the first 24–48 h. Moreover, it was found that the chromatic coordinates (L*a*b*) in normal wood and in red heartwood tended to similar values after 504 h. FTIR spectroscopy allowed for investigating the rate of photodegradation of wood surface due to oxidation reactions of wood components. The results were validated by statistical analysis applied both to the colorimetric and spectroscopic data.     

Aboveground respiratory CO2 effluxes from olive trees (Olea europaea L.)

The accurate assessment of respiration by woody vegetation, still a challenge in plant productivity models, is generally a problem of correctly scaling-up the process from organs to the whole plant. We used a large (41.6 m³), canopy chamber to enclose mature olive trees and to measure aboveground respiration (R _ag ) under natural environmental conditions in an irrigated olive orchard in Córdoba (Spain). The 3-year study assessed nocturnal and seasonal R _ag patterns in terms of temperature (T), plant dry matter composition, and phenology. The relative contributions of maintenance and growth respiration to R _ag were determined empirically via an independent experiment. Although short-term variations in R _ag rates were explained mainly by T variations, over seasonal time-scales this relationship was modulated by the vegetative composition of the olive trees and the contribution of growth respiration to R _ag when the plants, in different seasons, allocated most of the new assimilates to actively growing shoots, flowers or fruits. Leaf mass and fruit load were the main determinants of R _ag , which was weakly affected by differences in woody biomass since woody tissue respiration accounted for just 15 % of R _ag . Respiration in olive trees during fruit setting periods is composed of approximately 30 % growth and 70 % maintenance. This study provides an independent evaluation of how, and to what degree, seasonally varying plant organ composition determines total respiration. Improved modelling of ecosystem respiration can be achieved by accounting for plant biological patterns characterising energy-requiring growth and maintenance processes, since biochemical kinetics alone cannot explain the observed seasonal variability.     

Hunters'structured questionnaires enhance ecological knowledge and provide circumstantial survival evidence for the world's rarest turtle

1. Rafetus swinhoei, a giant softshell turtle from southern China and northern Vietnam, is the rarest turtle species on Earth, and only two individuals are known worldwide (one in the wild). There is very little ecological information for this species, and the remnant distribution remains completely unknown.
2. This article reports for the first time in the international literature the results of a structured questionnaire survey concerning the ecology and distribution of R. swinhoei in Vietnam. The standardized questionnaire consisted of 15 questions and was administered to 10 former Rafetus hunters with several years of experience in catching this species.
3. There was considerable consensus among the hunters regarding several aspects of the biology of R. swinhoei, with special reference to its reproductive and feeding habits. The mean weight of 58 captured individuals was 53 kg, with the majority of individuals weighing 15–40 kg (median = 40 kg) and only 17.2% of individuals weighing more than 100 kg.
4. Based on the hunters'answers, it was established that the population collapse of R. swinhoei in Vietnam occurred in two phases: first during the 1980s, when the population size dramatically decreased, and second, at the beginning of the 1990s, when many hunters simultaneously collected multiple individuals from populations already experiencing severe impacts. There was also a general agreement that these turtles became very rare after 1991–92.
5. In total, 90% of the hunters agreed that there should still be wild R. swinhoei individuals at their respective sites, and some of the hunters also reported a few recent sightings that they attributed to the target species.
6. As several sites of likely presence were identified, we suggest that extensive trapping should be planned at these sites in future.

     

Analysis of Stress-Induced Gene Expression in Trout Red Blood cells following Tributyltinchloride Exposure

Submicromolar concentrations of tributyltinchloride (TBTC), an organotin compound, is able to impair mitochondrial activity in trout erythrocytes, as detected by ultrastructural transmission electron microscopy investigations and exhibits pro apoptotic activity in a variety of cells including nucleated red blood cells. Here we show that TBTC is able to induce the expression of hsp70 in rainbow trout (Onchorynchus mykiss) erythrocytes in a time- and dose-dependent manner. This induction was demonstrated by quantification of the relative abundance of mRNA, and the synthesis of hsp70 was detected by means of an immunological test. This study could provide a practical assay of environmental stress at sublethal toxicant concentrations.     

Enhanced adherence of methicillin-resistant Staphylococcus pseudintermedius sequence type 71 to canine and human corneocytes

The recent worldwide spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs is a reason for concern due to the typical multidrug resistance patterns displayed by some MRSP lineages such as sequence type (ST) 71. The objective of this study was to compare the in vitro adherence properties between MRSP and methicillin-susceptible (MSSP) strains. Four MRSP, including a human and a canine strain belonging to ST71 and two canine non-ST71 strains, and three genetically unrelated MSSP were tested on corneocytes collected from five dogs and six humans. All strains were fully characterized with respect to genetic background and cell wall-anchored protein (CWAP) gene content. Seventy-seven strain-corneocyte combinations were tested using both exponential- and stationary-phase cultures. Negative binomial regression analysis of counts of bacterial cells adhering to corneocytes revealed that adherence was significantly influenced by host and strain genotype regardless of bacterial growth phase. The two MRSP ST71 strains showed greater adherence than MRSP non-ST71 (p < 0.0001) and MSSP (p < 0.0001). This phenotypic trait was not associated to any specific CWAP gene. In general, S. pseudintermedius adherence to canine corneocytes was significantly higher compared to human corneocytes (p < 0.0001), but the MRSP ST71 strain of human origin adhered equally well to canine and human corneocytes, suggesting that MRSP ST71 may be able to adapt to human skin. The genetic basis of the enhanced in vitro adherence of ST71 needs to be elucidated as this phenotypic trait may be associated to the epidemiological success and zoonotic potential of this epidemic MRSP clone.     

Evaluation of different enzyme-linked immunosorbent assays for the diagnosis of brucellosis due to Brucella melitensis in sheep

Six serological assays for the diagnosis of ovine brucellosis, due to Brucella melitensis were evaluated. Reference serum samples from sheep of known B. melitensis infection status (n = 118) were assessed using the Rose Bengal test (RBT), complement fixation test (CFT) and four commercial enzyme-linked immunosorbent assays (ELISAs), including two indirect ELISAs (iELISAs), one competitive ELISA (cELISA) and one blocking ELISA (bELISA).The highest differential positive rates (DPR) were obtained with the cELISA and bELISA, while the lowest DPR was estimated using iELISAs. A latent class analysis was performed to estimate the accuracy of the CFT, RBT and bELISA using 1827 sera from sheep undergoing testing as part of a surveillance and control programme. Lower sensitivity and specificity were obtained for the three serological tests when the field samples were used. A higher DPR was achieved by the CFT, compared to bELISA and RBT. The results suggest that ELISAs, and particularly the bELISA, might be suitable for inclusion in the European Union legislation on intra-community trade for diagnosing B. melitensis infection in sheep, as it has a similar test performance compared to the RBT.     

Fishers,dams, and the potential survival of the world's rarest turtle,Rafetus swinhoei,in two river basins in northern Vietnam

1. Next to cetaceans and megafishes, freshwater turtles are the most iconic endangered freshwater species.
2. A detailed questionnaire survey conducted with more than 100 individuals from fishing communities in northern Vietnam was used to investigate the current status of Southeast Asian turtles and provides new hope concerning the survival of Rafetus swinhoei, for which recent official records in the wild are limited to a single individual in Vietnam.
3. The survey included the entire Vietnamese portion of the Da River in Hoa Binh and Son La provinces, as well as the Chu and Ma river system in Thanh Hoa Province, as they are the last sites where the world's rarest and largest Asian softshell turtle has been seen. The questionnaire, conducted in Vietnamese, focused on demographic details, fishing intensity and gear, the status of fishing grounds, and the frequency of interaction with turtles.
4. The great majority of fishers could recognize different turtle species from photographs and describe their preferential breeding habitats; not all knew that they are protected. A few confirmed that more than once each year they still encounter freshwater turtles during their fishing activities.
5. This survey provides detailed information on sites where freshwater turtles are still seen in northern Vietnam and broadens our hope that wild individuals of the extremely rare R. swinhoei may still be present in the remaining riparian wetlands of these biodiverse, dammed, and controlled river basins in North Vietnam.

     

Location and stability of a recombinant ovine prion protein in synthetic humic-like mineral complexes

Location and stability of a recombinant prion protein (recPrP) and its interaction with humic-like complexes were investigated by low-temperature ashing (LTA), thermal gravimetric (TG), and scanning electron microscopy (SEM) analyses. Humic-like complexes were obtained by abiotic polymerization of catechol, one of the possible precursors of soil humic matter, through the catalysis of birnessite, a manganese oxide common in soil environment. The recPrP was immobilized in organomineral complexes via sorption or entrapment. Complexes were treated by LTA, allowing the controlled removal of organic matter layer by layer, from the external to the internal side, with minimal disturbance of mineral constituents. Thermal gravimetric and SEM analyses were performed on specimens before and after LTA treatment. Entrapped recPrP, compared with sorbed, resulted less easily accessible to LTA treatment and showed a higher thermal stability by TGA analyses. On the basis of these findings, we hypothesize that the processes leading to newly formed organic complexes can enhance prion stability in soil and thus influence the environmental diffusion of infectivity.     

BAX and BAK regulation of endoplasmic reticulum Ca2+: a control point for apoptosis

BAX and BAK are "multidomain" proapoptotic proteins that initiate mitochondrial dysfunction but also localize to the endoplasmic reticulum (ER). Mouse embryonic fibroblasts deficient for BAX and BAK (DKO cells) were found to have a reduced resting concentration of calcium in the ER ([Ca2+]er) that results in decreased uptake of Ca2+ by mitochondria after Ca2+ release from the ER. Expression of SERCA (sarcoplasmic-endoplasmic reticulum Ca2+ adenosine triphosphatase) corrected [Ca2+]er and mitochondrial Ca2+ uptake in DKO cells, restoring apoptotic death in response to agents that release Ca2+ from intracellular stores (such as arachidonic acid, C2-ceramide, and oxidative stress). In contrast, targeting of BAX to mitochondria selectively restored apoptosis to "BH3-only" signals. A third set of stimuli, including many intrinsic signals, required both ER-released Ca2+ and the presence of mitochondrial BAX or BAK to fully restore apoptosis. Thus, BAX and BAK operate in both the ER and mitochondria as an essential gateway for selected apoptotic signals.