Exploring beliefs behind support for and opposition to wildlife management methods: a qualitative study

Wildlife management methods such as culling (lethal control) and fencing can be controversial in some circumstances. Such controversy can be problematic for decision-makers or those managing decision-making processes and can lead to management delays or inertia. Understanding the reasons why people support or oppose specific management methods is therefore an important objective for researchers. Attitudes towards methods are in part based on individual beliefs about those methods, the species of wildlife being managed and other associated phenomena. This paper adopts a qualitative approach to develop understanding of these beliefs. We conducted 17 focus-groups on wild deer management at two locations in Britain, with both ‘professional’ land manager and ‘public’ participants (n?=?103). We identified a number of individual beliefs which are grouped into five categories: naturalness, overabundance, impacts, effectiveness and animal welfare. Our findings suggest that potentially controversial management methods will receive most support where the objective is to maintain a ‘natural’ environment, at sites where impacts are evident, and when using targeted and effective methods.     

Comparison of standardized mortality ratios (SMRs) obtained from use of reference populations based on a company-wide registry cohort to SMRs calculated against local and national rates

The DuPont Company has maintained a mortality registry for all active and pensioned U.S. employees since 1957. Standardized mortality ratios (SMRs) for each plant site in the U.S. can be calculated based on the comparison with the entire U.S. DuPont population or with a regional subset of DuPont employees. We compared the SMRs derived from a large, international cohort mortality study of chloroprene workers (IISRP study) with those derived from the entire DuPont Registry and appropriate subpopulations of the registry for two U.S. neoprene plants--Louisville (Kentucky) and Pontchartrain (Louisiana). SMRs from the IISRP study for the Louisville cohort based on national rates for all causes of death, all cancers, respiratory cancer, and liver cancer are higher than those based on local mortality rates. Both the national and local comparisons (several counties surrounding each plant) for all-cancer SMRs are lower than 1.0, the local comparison being statistically significantly reduced. In contrast, the SMRs based on the total U.S. DuPont worker mortality rates for all causes of death (1.13), all cancers (1.11), and respiratory cancers (1.37) are statistically significantly increased. The SMR for liver cancer (1.27), although elevated, is not statistically significant. SMRs based on DuPont Region 1 were closer to 1.0, and the SMR for all cancers was no longer significant. Stratification of the Louisville subcohort of males using the same cumulative exposure categories used in the IISRP study yielded SMRs calculated against DuPont Region 1 that were generally higher than those calculated against U.S. and local rates. Only the third exposure category showed SMRs statistically significantly above 1.0 for all cancers and for cancer of bronchus, trachea, and lung. However, there does not appear to be an exposure-response trend. The SMRs from the IISRP study for the Pontchartrain cohort based on national rates are higher than those based on local rates for all causes of death, but all are less than 1.0. The all-cause SMRs for both local and national comparisons are significantly reduced. There were no deaths from liver cancers observed in this cohort. Comparisons of the Pontchartrain cohort against the total U.S. DuPont worker mortality rates resulted in higher SMRs for all causes of death (0.98), all cancers (1.03), and respiratory cancer (1.08), but none were statistically significant. SMRs based on DuPont Region 2 showed very little change from those based on the total registry. The use of reference rates based on regional workers in the same large company produces SMRs lower than those based on the entire company population (regional socio-cultural effects) but higher than those based on geographically closer local general populations (healthy worker effect). The healthy worker effect is seen in cancer mortality rates as well as in other chronic diseases.     

The relationship between postmating reproductive isolation and reinforcement in Phlox

The process of speciation involves the accumulation of reproductive isolation (RI) between diverging lineages. Selection can favor increased RI via the process of reinforcement, whereby costs to hybridization impose selection for increased prezygotic RI. Reinforcement results in phenotypic divergence within at least one taxon, as a result of costly hybridization between sympatric taxa. The strength of selection driving reinforcement is determined by the cost of hybridization and the frequency of hybridization. We investigated the cost of hybridization by quantifying postmating RI barriers among Phlox species that comprise one of the best‐studied cases of reinforcement. We determined if the strength of RI differs among lineages that have and have not undergone reinforcement, how much variability there is within species in RI, and whether RI is associated with phylogenetic relatedness. We found high RI for the species that underwent phenotypic divergence due to reinforcement; however, RI was also high between other species pairs. We found extensive variability in RI among individuals within species, and no evidence that the strength of RI was associated with phylogenetic relatedness. We suggest that phenotypic divergence due to reinforcement is associated with the frequency of hybridization and introgression, and not the cost of hybridization in this clade.     

Population genomic analysis of a bacterial plant pathogen: novel insight into the origin of Pierce's disease of grapevine in the U.S

Invasive diseases present an increasing problem worldwide; however, genomic techniques are now available to investigate the timing and geographical origin of such introductions. We employed genomic techniques to demonstrate that the bacterial pathogen causing Pierce's disease of grapevine (PD) is not native to the US as previously assumed, but descended from a single genotype introduced from Central America. PD has posed a serious threat to the US wine industry ever since its first outbreak in Anaheim, California in the 1880s and continues to inhibit grape cultivation in a large area of the country. It is caused by infection of xylem vessels by the bacterium Xylella fastidiosa subsp. fastidiosa, a genetically distinct subspecies at least 15,000 years old. We present five independent kinds of evidence that strongly support our invasion hypothesis: 1) a genome-wide lack of genetic variability in X. fastidiosa subsp. fastidiosa found in the US, consistent with a recent common ancestor; 2) evidence for historical allopatry of the North American subspecies X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa; 3) evidence that X. fastidiosa subsp. fastidiosa evolved in a more tropical climate than X. fastidiosa subsp. multiplex; 4) much greater genetic variability in the proposed source population in Central America, variation within which the US genotypes are phylogenetically nested; and 5) the circumstantial evidence of importation of known hosts (coffee plants) from Central America directly into southern California just prior to the first known outbreak of the disease. The lack of genetic variation in X. fastidiosa subsp. fastidiosa in the US suggests that preventing additional introductions is important since new genetic variation may undermine PD control measures, or may lead to infection of other crop plants through the creation of novel genotypes via inter-subspecific recombination. In general, geographically mixing of previously isolated subspecies should be avoided.     

Drug Effect Unveils Inter-head Cooperativity and Strain-dependent ADP Release in Fast Skeletal Actomyosin

Amrinone is a bipyridine compound with characteristic effects on the force-velocity relationship of fast skeletal muscle, including a reduction in the maximum shortening velocity and increased maximum isometric force. Here we performed experiments to elucidate the molecular mechanisms for these effects, with the additional aim to gain insight into the molecular mechanisms underlying the force-velocity relationship. In vitro motility assays established that amrinone reduces the sliding velocity of heavy meromyosin-propelled actin filaments by 30% at different ionic strengths of the assay solution. Stopped-flow studies of myofibrils, heavy meromyosin and myosin subfragment 1, showed that the effects on sliding speed were not because of a reduced rate of ATP-induced actomyosin dissociation because the rate of this process was increased by amrinone. Moreover, optical tweezers studies could not detect any amrinone-induced changes in the working stroke length. In contrast, the ADP affinity of acto-heavy meromyosin was increased about 2-fold by 1 mm amrinone. Similar effects were not observed for acto-subfragment 1. Together with the other findings, this suggests that the amrinone-induced reduction in sliding velocity is attributed to inhibition of a strain-dependent ADP release step. Modeling results show that such an effect may account for the amrinone-induced changes of the force-velocity relationship. The data emphasize the importance of the rate of a strain-dependent ADP release step in influencing the maximum sliding velocity in fast skeletal muscle. The data also lead us to discuss the possible importance of cooperative interactions between the two myosin heads in muscle contraction.Muscle contraction, as well as several other aspects of cell motility, results from cyclic interactions between myosin II motors and actin filaments. These force-generating interactions are driven by the hydrolysis of ATP at the myosin active site as outlined in Scheme 1 (1–3). In the absence of actin, the P_i and ADP release steps (k₄ and k₅) are rate-limiting for the entire cycle at high (>12 °C) and low temperatures, respectively (4–6). In the presence of actin, the rate of P_i release increases significantly, and the overall cycle is accelerated more than 2 orders of magnitude. The sliding velocity of myosin-propelled motors is generally believed to be rate-limited by actomyosin dissociation (rate constant k′₅, k′₆, or k′₂ in Scheme 1) (7). Alternatively, some studies (8, 9) have suggested that the sliding velocity is determined by the fraction of myosin heads in the weak-binding states, AM⁴ ATP and AM ADP P_i. However, it is worth emphasizing that K_T is very low under physiological conditions (1, 3) with low population of these states. For the same reason, the rate of dissociation of the AM complex is governed by K′₁ and k′₂.Open in a separate windowSCHEME 1.Simplified kinetics scheme for MgATP turnover by myosin (lower row) and actomyosin (upper row). Inorganic phosphate is denoted by P_i; MgATP is denoted by ATP, and MgADP is denoted by ADP; myosin is denoted by M. The states AM*ADP and AM ADP correspond to myosin heads with their nucleotide binding pocket in a partially closed and open conformation, respectively (7, 52). Rate constants are indicated by lowercase letters (rightward transitions, k₂ − k₅ and k′₂ − k′₅, or leftward transitions, k₋₂ − k₋₅ and k′₋₂ − k′₋₅) and equilibrium constants by uppercase letters (K₁, K′₁, K_T, K₃, K′₃, K₆, k′₆, and K_DP). The equilibrium constants are association constants except for simple bimolecular reactions where they are defined as k_i/k_−i.For the study of contractile mechanisms in both muscle and other types of cells, drugs may be useful as pharmacological tools affecting different transitions or states in the force-generating cycle. Whereas the use of drugs as tools may be less specific than site-directed mutagenesis, it also has advantages. The motor protein function may be studied in vivo, with maintained ordering of the protein components, e.g. as in the muscle sarcomere, allowing more insight into the relationship between specific molecular events and contractile properties of muscle. A drug that has been used quite extensively in this context is butanedione monoxime. The usefulness of this drug is based on firm characterization of its effect on actomyosin function on the molecular level (3, 10–13). More recently other drugs, like N-benzyl-p-toluene sulfonamide (14, 15) and blebbistatin (16), have been found to affect myosin function, and their effects at the molecular level have also been elucidated in some detail (14, 15, 17, 18). Both these drugs appear to affect the actomyosin interaction in a similar way as butanedione monoxime by inhibiting a step before (or very early in) the myosin power stroke, leading to the inhibition of actomyosin cross-bridge formation and force production.In contrast to the reduced isometric force, caused by the above mentioned drugs, the bipyridine compound amrinone (Fig. 1A) has been found to increase the isometric force production of fast intact skeletal muscles of the frog (19, 20) and mouse (21) and also of fast (but much less slow) skinned muscle fibers of the rat (22). In all the fast myosin preparations, the effect of about 1 mm amrinone on isometric force was associated with characteristic changes of the force-velocity relationship (Fig. 1B), including a reduced maximum velocity of shortening (19–22) and a reduced curvature of the force-velocity relationship (19–22). The latter effect was accompanied (20, 21) by a less pronounced deviation of the force-velocity relationship from the hyperbolic shape (23) at high loads. There have been different interpretations of the drug effects. It has been proposed (20–22) that amrinone might competitively inhibit the MgATP binding by myosin. However, more recently, results from in vitro motility assay experiments (24) challenged this idea. These results showed that amrinone reduces the sliding velocity (V_max) at saturating MgATP concentrations but not at MgATP concentrations close to, or below, the K_m value for the hyperbolic relationship between MgATP concentration and sliding velocity. Such a combination of effects is consistent with a reduced MgADP release rate (24) but not with competitive inhibition of substrate binding. However, effects of amrinone on the MgADP release rate have not been directly demonstrated. Additionally, in view of the uncertainty about what step actually determines the sliding velocity at saturating [MgATP] (see above and Refs. 7–9), it is of interest to consider other possible drug effects that could account for the data of Klinth et al. (24). These include the following: 1) an increased drag force, e.g. because of enhancement of weak actomyosin interactions; 2) a reduced step length; and 3) effects of the drug on the rate of MgATP-induced dissociation of actomyosin.Open in a separate windowFIGURE 1.A, structure of amrinone. B, experimental force-velocity data obtained in the presence (filled symbols) and absence (open symbols) of 1.1 mm amrinone. The data, from intact single frog muscle fibers, were obtained at 2 °C and fitted by Hill''s (42) hyperbola (lines) for data truncated at 80% of the maximum isometric force. Filled line, equation fitted to control data, a/P₀* = 0.185; P₀*/P₀ = 1.196. Dashed line, amrinone, a/P₀* = 0.347; P₀*/P₀ = 1.009. Force-velocity data were obtained in collaboration with Professor K. A. P. Edman. Same data as in Fig. 8 of Ref. 20. Note a decrease in maximum sliding velocity and curvature of the force-velocity relationship at low force, in response to amrinone. Also note that amrinone caused increased isometric force and a reduced deviation of the force-velocity relationship from the Hill''s hyperbola at high force. All changes of the force-velocity relationship were statistically significant (20), and similar changes were later also observed in intact mouse muscle and skinned rat muscle fibers. Data in Fig. 1 are published by agreement with Professor K. A. P. Edman.To differentiate between these hypotheses for the amrinone effects, and to gain more general insight into fundamental aspects of muscle function (e.g. mechanisms underlying the force-velocity relationship), we here study the molecular effects of amrinone on fast skeletal muscle myosin preparations in the presence and absence of actin.In vitro motility assay studies at different ionic strengths suggest that drag forces, caused by increased fraction of myosin heads in weak binding states, are not important for the effect of amrinone on sliding velocity. Likewise, optical tweezers studies showed no effect of the drug on the myosin step length. Finally, ideas that amrinone should reduce sliding velocity by reduced rate of MgATP-induced dissociation could be discarded because the drug actually increased the rate of this process. Instead, we found an amrinone-induced increase in the MgADP affinity of heavy meromyosin (HMM) in the presence of actin. Interestingly, similar effects of amrinone were not observed using myosin S1. As discussed below, this result and other results point to an amrinone-induced reduction in the rate of a strain-dependent MgADP release step. Simulations, using a model modified from that of Edman et al. (25), support this proposed mechanism of action. The results are discussed in relation to fundamental mechanisms underlying the force-velocity relationship of fast skeletal muscle, including which step determines shortening velocity and the possible importance of inter-head cooperativity.     

Effect of two types of biosurfactants on phenanthrene availability to the bacterial bioreporter Burkholderia sartisoli strain RP037

Biosurfactants are tensio-active agents that have often been proposed as a means to enhance the aqueous solubility of hydrophobic organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). Biosurfactant-producing bacteria such as those belonging to the genus Pseudomonas might therefore enhance PAH availability to PAH-degrading bacteria. We tested the effects of two types of biosurfactants produced by Pseudomonas sp., cyclic lipopeptides and rhamnolipids, on phenanthrene bioavailability. Bioavailability was judged from growth rates on phenanthrene and from specific induction of a phenanthrene-responsive GFP-reporter in Burkholderia sartisoli strain RP037. Co-culturing of strain RP037 with the lipopeptide-producing bacterium Pseudomonas putida strain PCL1445 enhanced GFP expression compared to a single culture, but this effect was not significantly different when strain RP037 was co-cultivated with a non-lipopeptide-producing mutant of P. putida. The addition of partially purified supernatant extracts from the P. putida lipopeptide producer equally did not unequivocally enhance phenanthrene bioavailability to strain RP037 compared to controls. In contrast, a 0.1% rhamnolipid solution strongly augmented RP037 growth rates on phenanthrene and led to a significantly larger proportion of cells in culture with high GFP expression. Our data therefore suggest that biosurfactant effects may be strongly dependent on the strain and type of biosurfactant.     

Modulation of lymphocyte function with inhibitory CD2: loss of NK and NKT cells

Analysis of the NK cell developmental pathway suggests that CD2 expression may be important in regulating NK maturation. To test this hypothesis, we developed mice containing only an inhibitory CD2 molecule by linking the extracellular domain of CD2 to an intracellular immunoreceptor tyrosine-based inhibitory motif (ITIM) motif. Mice containing the CD2 Tg(ITIM) transgene, introduced into a CD2 KO background, have no morphologically detectable lymph nodes, although development of the thymus appears normal. In addition, these mice had major loss of both NK and NKT subsets in peripheral organs, while T and B cell frequencies were intact. Expression of CD2 was low on T cells and lacking on B cells and functional defects were observed in these populations. NKT cells expressing CD4 were absent, while the CD8⁺ and double negative NKT cells were retained. Small subsets of NK cells were detected but expression of CD2 on these cells was very low or absent, and their maturation was impaired. Based on the phenotype described here, we believe that these mice represent a unique model to study lymphoid organ and lymphocyte development.     

Consequences of terbium (111) binding on the conformation and enzymatic activity of Guinea pig liver transglutaminase

Calcium ions are crucial for expression of transglutaminase activity. Although lanthanides have been reported to substitute for calcium in a variety of protein functions, they did not replace the calcium requirement during transglutaminase activity measurements. Furthermore, lanthanides strongly inhibited purified liver transglutaminase activity using either casein or fibrinogen as substrates. Terbium (III) inhibition of transglutaminase-catalyzed putrescine incorporation into casein was not reversed by the presence of 10–200 fold molar excess of calcium ions (Ki for Tb(III)=60 µM). Conformational changes in purified liver transglutaminase upon Tb(III) binding were evident from a biphasic effect of Tb(III) on transglutaminase binding to fibrin. Low concentrations of Tb(III) (1 µM to 10 µM inhibited the binding of transglutaminase to fibrin, whereas higher concentrations (20 µM to 100 µM promoted binding. Conformational changes in purified liver transglutaminase consequent to Tb(III) binding were also demonstrated by fluorescence spectroscopy due to Forster energy transfer. Fluorescence emission was stable to the presence of 200 mM NaCl and 100 mM CaCl₂ only partially quenched emission. Purified liver transglutaminase strongly bound to Tb(III)-Chelating Sepharose beads and binding could not be disrupted by 100 mM CaCl₂ solution. Our data suggest that Tb(III)-induced conformational changes in transglutaminase are responsible for the observed effects on enzyme structure and function. The potential applications of Tb(III)-transglutaminase interactions in elucidating the structure-function relationships of liver transglutaminase are discussed.     

Mapping the economic costs and benefits of conservation

Resources for biodiversity conservation are severely limited, requiring strategic investment. Understanding both the economic benefits and costs of conserving ecosystems will help to allocate scarce dollars most efficiently. However, although cost-benefit analyses are common in many areas of policy, they are not typically used in conservation planning. We conducted a spatial evaluation of the costs and benefits of conservation for a landscape in the Atlantic forests of Paraguay. We considered five ecosystem services (i.e., sustainable bushmeat harvest, sustainable timber harvest, bioprospecting for pharmaceutical products, existence value, and carbon storage in aboveground biomass) and compared them to estimates of the opportunity costs of conservation. We found a high degree of spatial variability in both costs and benefits over this relatively small (~3,000 km²) landscape. Benefits exceeded costs in some areas, with carbon storage dominating the ecosystem service values and swamping opportunity costs. Other benefits associated with conservation were more modest and exceeded costs only in protected areas and indigenous reserves. We used this cost-benefit information to show that one potential corridor between two large forest patches had net benefits that were three times greater than two otherwise similar alternatives. Spatial cost-benefit analysis can powerfully inform conservation planning, even though the availability of relevant data may be limited, as was the case in our study area. It can help us understand the synergies between biodiversity conservation and economic development when the two are indeed aligned and to clearly understand the trade-offs when they are not.