The influence of fruit abundance on the use of forest and cultivated field habitats by the endemic Madeira laurel pigeon Columba trocaz: Implications for conservation

This study was conducted over a two year period in the north west of Madeira Island (Macaronesian Atlantic Islands, Portugal). It investigates the relationship between fruiting patterns in the indigenous forest and the use by the Madeira laurel pigeon of forest habitats and cultivated areas. Habitat use observations were carried out using line-transects in forest sites where the availability of fruit (the most important element of the diet) was assessed. The use of agricultural fields was measured indirectly by the assessment of the damage caused to crops. The findings provided strong evidence that bird movements and shifts in abundance are related to fruit usage and availability. The use of fruits is mostly opportunistic but when many species are available, selection was observed. From an ecological perspective, our findings indirectly confirm a high concordance between pigeon diet, studied by microhistological techniques, and habitat use. The use of crops also seems to be mostly opportunistic and is governed by the birds’ movements within the adjacent forest. It is hypothesised that fruit phenology will influence the use of agricultural areas only to the extent that it governs such movements; there is no strong evidence that crops are attacked only when the availability of natural foods is low. Our results suggest that the current management strategy for the forest is adequate for the conservation of this pigeon but that the conservation value of forest edges should be redefined. It is also proposed that crop damage may be reduced by identifying the proximate factors, which lead to the use of specific fields.     

Influence of soil and host plant crop on the genetic diversity of Azospirillum amazonense isolates

The genetic structure of Azospirillum amazonense populations isolated from the rhizosphere soil and washed and surface-sterilised roots of rice, maize and sorghum plants, cropped simultaneously in two different soils (clay loam and sandy loam) was characterised. Genetic diversity was measured by restriction fragment length polymorphism of the amplified 16S–23S rDNA intergenic spacer region (RISA-RFLP) and cluster analysis. Four genetically distinct clusters of isolates were observed with 78% similarity, suggesting that the A. amazonense population was heterogeneous at the strain level regardless of the soil type or host plant. Analysis of molecular variance (AMOVA) demonstrated that the host plant had a highly significant selective effect on the genetic structure of this species, especially on those isolates intimately associated with them, but also to a lesser extent on isolates from the rhizosphere and washed roots. The soil type also had a highly significant selective effect on A. amazonense genetic diversity, especially for those isolates from the rhizosphere soil. The selective effect of the soil type combined with that of the host plant suggests that environmental factors, such as soil texture and composition of exudates provided by C₃ or C₄ plants, play major roles in the overall genetic structure of A. amazonense populations associated with these cereals.     

Interaction of contaminated sediment from a salt marsh with estuarine water: evaluation by leaching and ecotoxicity assays and salts from leachate evaporation

Purpose

Wastes from a former Portuguese steel plant were deposited between 1961 and 2001 on the riverbank of a tributary of the Tagus River creating a landfill connected to the river, posing a potential contamination risk to the Tagus estuary ecosystem. This study aims to assess the transfer of chemical elements from contaminated sediments to the estuarine water from cycles of sediment leaching so as to evaluate the ecotoxicity of the leachates, and to analyze the solid phases crystallized from those leachates.

Materials and methods

Landfill sediment and estuarine water samples were collected during low tide. Sediment samples were analyzed for pH, electric conductivity (EC), C_org, NPK, and iron oxides. Leaching assays (four replicates) were done using estuarine water (200 cm³/replicate) and 1.5 kg of sediment per reactor. Each reactor was submitted to four leaching processes (0, 28, 49, and 77 days). The sediment was kept moist between leaching processes. Sediment (total (acid digestion) and available fraction (diluted organic acid extraction-Rhizo)) elemental concentrations were determined by inductively coupled plasma–instrumental neutron activation analysis (ICP/INAA). Leachates, and estuarine and sediment pore waters were analyzed for metals/metalloids by ICP/mass spectrometry (MS) and carbonates/sulfate/chloride by standard methodologies. Ecotoxicity assays were performed in leachates and estuarine and pore waters using Artemia franciscana and Brachionus plicatillis. Aliquots of the leachates were evaporated to complete dryness (23–25 °C) and crystals analyzed by X-ray powder diffraction (XRD).

Results and discussion

Sediment with pH?=?8 and high EC and C_org was contaminated with As, Cd, Cr, Cu, Pb, and Zn. The element concentrations in the available fraction of the sediment were low compared to the sediment total concentrations (<1 % for Rhizo extraction). The concentrations of potentially hazardous elements in the estuarine water were relatively low, except for Cd. Concentrations of hazardous elements in the leachates were very low. Calcium, K, Mg, Na, and chloride concentrations were high but did not vary significantly among the four leaching experiments. Total concentrations of carbonate were much higher in leachates than in estuarine water. Both estuarine water and leachates showed negligible toxicity. Crystals identified in the solids obtained from the leachates by evaporation were halite, anhydrite, epsomite, dolomite, and polyhalite.

Conclusions

The sediment showed the capacity to retain the majority of the potentially hazardous chemical elements. Remobilization of chemical elements from sediment by leaching was essentially negligible. The variation of total concentrations of Ca, carbonate, and sulfate in leachates indicates that the sediment contained reactive sulfides. Due to its composition, the sediment seems to be a dynamic system of pollution control, which should not be disturbed.

     

In situ evaluation of fruit yield and estimation of repeatability coefficient for major fruit traits of umbu tree [Spondias tuberosa (Anacardiaceae)] in the semi-arid region of Brazil

The umbu tree (Spondias tuberosa) is a xerophytic woody species endemic to the northeast of Brazil. The present work reports a three-year in situ evaluation of major yield components in a random set of trees in Petrolina city, Pernambuco State, Brazil and the application of repeatability coefficient in the context of genetic resources utilization. Five traits were assessed: total fruit yield per plant (FY); total number of fruits per plant (NF); average fruit weight (FW); average pulp weight (PW) and average fruit diameter (FD). The values observed for FY ranged from 4.2–184 kg with mean of 61.5 kg. The values for NF ranged from 257 to 12,981 fruits/tree with mean 3,993 fruits. For FW, the range was from 10.82–23.36 g with mean of 16.03 g. The values for PW ranged from 7 to 17 g with mean of 11.2 g, while FD values varied from 2.5 to 3.5 cm with mean of 3.0 cm. Six methods were employed to estimate repeatability coefficient (r) for all parameters. The r ranged from 0.68–0.76 for NF; 0.87–0.89 for FW; 0.65–0.75 for FY; 0.64–0.78 for PW and 0.70–0.84 for FD. Narrower ranges across methods were observed to r-values greater than 0.80, as observed for FW and FD. Three to four years of measurements will be necessary for FY, NF, and PW and one year for FW to obtain a precision of 90% to provide a reliable identification of individuals for in situ or ex situ conservation.     

Malignant activation of a K-ras oncogene in lung carcinoma but not in normal tissue of the same patient

A single genetic alteration, a guanine-to-cytosine transversion, is responsible for the acquisition of malignant properties by K-ras genes of two human tumor cell lines established from carcinomas of the bladder (A1698) and lung (A2182). As a consequence, arginine instead of the normal glycine is incorporated into the K-ras-coded p21 proteins at amino acid position 12. This mutation creates a restriction enzyme polymorphism that can be used to screen human cells for transforming K-ras genes. This approach was used to identify the mutational event responsible for the malignant activation of a K-ras oncogene in a squamous cell lung carcinoma of a 66-year-old man; this point mutation was not present in either the normal bronchial or parenchymal tissue or in the blood lymphocytes. Hence, malignant activation of a ras oncogene appears to be specifically associated with the development of a human neoplasm.     

Carbon-based supercapacitors produced by activation of graphene

Supercapacitors, also called ultracapacitors or electrochemical capacitors, store electrical charge on high-surface-area conducting materials. Their widespread use is limited by their low energy storage density and relatively high effective series resistance. Using chemical activation of exfoliated graphite oxide, we synthesized a porous carbon with a Brunauer-Emmett-Teller surface area of up to 3100 square meters per gram, a high electrical conductivity, and a low oxygen and hydrogen content. This sp(2)-bonded carbon has a continuous three-dimensional network of highly curved, atom-thick walls that form primarily 0.6- to 5-nanometer-width pores. Two-electrode supercapacitor cells constructed with this carbon yielded high values of gravimetric capacitance and energy density with organic and ionic liquid electrolytes. The processes used to make this carbon are readily scalable to industrial levels.     

Adapting the IUCN Red List criteria for invertebrates

The IUCN Red List is the most useful list of species that are at risk for extinction worldwide, as it relies on a number of objective criteria. Nevertheless, there is a taxonomic bias that excludes species with small body sizes, narrow distribution ranges and low dispersal abilities, which constitute the vast majority of the planet’s biota, particularly local endemics.By evaluating each IUCN criterion separately, we (i) identify the shortcomings for invertebrate applications, (ii) explain how risk categories may be wrongly applied due to inapplicable and/or misleading thresholds, (iii) suggest alternative ways of applying the existing criteria in a more realistic way and (iv) suggest possible new criteria that were not considered in the current evaluation framework but that could allow a more comprehensive and effective assessment of invertebrates.By adapting the criteria to rely more explicitly on the Area of Occupancy and the Extent of Occurrence, their respective trends and by using ecological modelling methods, the criteria’s applicability would be increased. The change in some thresholds or, eventually, the creation of sub-categories would further increase their adequacy. Additionally, co-extinction could be introduced as an explicit part of the classification process.As a case study, we evaluated 48 species of Azorean arthropods and Iberian spiders according to the current criteria. More than one-quarter (27%) of all evaluated species were classified as Critically Endangered, 19% as Endangered, 6% as Vulnerable and 8% as Least Concern. The remaining 40% did not have enough data to reach a classification.     

Performance of four <Emphasis Type="Italic">Trichogramma</Emphasis> species (Hymenoptera: Trichogrammatidae) as biocontrol agents of <Emphasis Type="Italic">Heliothis virescens</Emphasis> (Lepidoptera: Noctuidae) under various temperature regimes

Trichogramma spp. are major parasitoids of lepidopteran pest eggs, but there is large variation in efficacy toward a given pest among the numerous described Trichogramma species. It is important to select the Trichogramma species that most effectively parasitize and develop in target pest eggs for biological control. In this context, Trichogramma pretiosum, T. exiguum, T. atopovirilia and T. acacioi were studied in Heliothis virescens eggs under different thermal conditions. The parasitoids were reared at constant temperatures of 20, 25 and 30°C and tested at these respective temperatures, while parasitoids reared at 25°C were also tested at 20 and 30°C, for a total of 20 species–temperature combinations. About 30 H. virescens eggs were offered to the parasitoids for 24 h. Among the four species, parasitism rate by T. atopovirilia was highest at all temperature conditions, whereas T. acacioi had the lowest rates of parasitism at 25°C and 25/30°C. Parasitism ranged from 13.8 to 43.8% among all species–temperature combinations. Viability (emerged parasitoids) ranged from 80.8 to 98.4%, and was deemed satisfactory. The emergence rates of T. exiguum and T. acacioi were affected by temperature. Temperature also affected the sex ratio of T. exiguum at 25/30°C, whereas T. pretiosum and T. acacioi produced females predominantly independent of temperature. Overall, the parasitoid T. atopovirilia was the most efficient in parasitizing H. virescens eggs, though the levels of parasitism obtained might not ensure its successful use in biological control programs. The temperature-related differences in biological traits observed in the four Trichogramma species tested hint at the importance of making careful choices regarding climatic conditions where the parasitoid is going to be used when selecting a species for biological control programs.     

Using BCG,MPT-51 and Ag85 as antigens in an indirect ELISA for the diagnosis of bovine tuberculosis

This study evaluated the Mycobacterium tuberculosis protein antigen MPT-51, the trimeric antigen 85 (Ag85) complex, and Bacillus Calmette-Guérin (BCG) in an indirect ELISA to diagnose bovine tuberculosis (TB) from serum samples. Serum was collected from 208 intra-dermal tuberculin test (ITT)-positive and 54 ITT-negative animals from a region where bovine TB is endemic. Using the Ag85 and BCG antigens, the indirect ELISA was able to discriminate ITT-positive from ITT-negative animals. This level of discrimination was not achieved when using the MPT-51 antigen. The highest sensitivity (Se) and specificity (Sp) of the test was found when BCG was used (Se, 82%; Sp, 91%). Further work in different epidemiological settings and with larger numbers of animals will be required to validate these findings.     

A clinical comparison of remifentanil or alfentanil in propofol-anesthetized cats undergoing ovariohysterectomy

Sixteen cats were used to compare the cardiovascular and anesthetic effects of remifentanil (REMI) or alfentanil (ALF) in propofol-anesthetized cats undergoing ovariohysterectomy. After premedication with acepromazine, anesthesia was induced and maintained with a constant rate infusion of propofol (0.3 mg/kg/min). REMI or ALF infusions were administered simultaneously with propofol. Heart rate (HR), systolic arterial pressure (SAP), pulse oximetry (SpO(2)), rectal temperature (RT), and response to surgical stimulation were recorded at predefined time points during anesthesia. Data [mean±standard deviation (SD)] were analyzed by analysis of variance (ANOVA) for repeated measures followed by a Dunnett's test and Student t-test (P<0.05). SAP was significantly lower in ALF group than in REMI group. Extubation time was significantly shorter in REMI than in ALF group. Overall infusion rate of REMI and ALF was 0.24±0.05 μg/kg/min and 0.97±0.22 μg/kg/min, respectively. The combination of propofol and REMI or ALF provided satisfactory anesthesia in cats undergoing ovariohysterectomy.