Spatial genetic structure in American black bears (Ursus americanus): female philopatry is variable and related to population history.

Previously, American black bears (Ursus americanus) were thought to follow the pattern of female philopatry and male-biased dispersal. However, recent studies have identified deviations from this pattern. Such flexibility in dispersal patterns can allow individuals greater ability to acclimate to changing environments. We explored dispersal and spatial genetic relatedness patterns across ten black bear populations-including long established (historic), with known reproduction >50 years ago, and newly established (recent) populations, with reproduction recorded <50 years ago-in the Interior Highlands and Southern Appalachian Mountains, United States. We used spatially explicit, individual-based genetic simulations to model gene flow under scenarios with varying levels of population density, genetic diversity, and female philopatry. Using measures of genetic distance and spatial autocorrelation, we compared metrics between sexes, between population types (historic and recent), and among simulated scenarios which varied in density, genetic diversity, and sex-biased philopatry. In empirical populations, females in recent populations exhibited stronger patterns of isolation-by-distance (IBD) than females and males in historic populations. In simulated populations, low-density populations had a stronger indication of IBD than medium- to high-density populations; however, this effect varied in empirical populations. Condition-dependent dispersal strategies may permit species to cope with novel conditions and rapidly expand populations. Pattern-process modeling can provide qualitative and quantitative means to explore variable dispersal patterns, and could be employed in other species, particularly to anticipate range shifts in response to changing climate and habitat conditions.

Influence of drift and admixture on population structure of American black bears (Ursus americanus) in the Central Interior Highlands, USA, 50 years after translocation.

Bottlenecks, founder events, and genetic drift often result in decreased genetic diversity and increased population differentiation. These events may follow abundance declines due to natural or anthropogenic perturbations, where translocations may be an effective conservation strategy to increase population size. American black bears (Ursus americanus) were nearly extirpated from the Central Interior Highlands, USA by 1920. In an effort to restore bears, 254 individuals were translocated from Minnesota, USA, and Manitoba, Canada, into the Ouachita and Ozark Mountains from 1958 to 1968. Using 15 microsatellites and mitochondrial haplotypes, we observed contemporary genetic diversity and differentiation between the source and supplemented populations. We inferred four genetic clusters: Source, Ouachitas, Ozarks, and a cluster in Missouri where no individuals were translocated. Coalescent models using approximate Bayesian computation identified an admixture model as having the highest posterior probability (0.942) over models where the translocation was unsuccessful or acted as a founder event. Nuclear genetic diversity was highest in the source (AR = 9.11) and significantly lower in the translocated populations (AR = 7.07-7.34; P = 0.004). The Missouri cluster had the lowest genetic diversity (AR = 5.48) and served as a natural experiment showing the utility of translocations to increase genetic diversity following demographic bottlenecks. Differentiation was greater between the two admixed populations than either compared to the source, suggesting that genetic drift acted strongly over the eight generations since the translocation. The Ouachitas and Missouri were previously hypothesized to be remnant lineages. We observed a pretranslocation remnant signature in Missouri but not in the Ouachitas.

Comparison of geomechanical deformation induced by megatonne-scale CO2 storage at Sleipner, Weyburn, and In Salah.

Geological storage of CO2 that has been captured at large, point source emitters represents a key potential method for reduction of anthropogenic greenhouse gas emissions. However, this technology will only be viable if it can be guaranteed that injected CO2 will remain trapped in the subsurface for thousands of years or more. A significant issue for storage security is the geomechanical response of the reservoir. Concerns have been raised that geomechanical deformation induced by CO2 injection will create or reactivate fracture networks in the sealing caprocks, providing a pathway for CO2 leakage. In this paper, we examine three large-scale sites where CO2 is injected at rates of ~1 megatonne/y or more: Sleipner, Weyburn, and In Salah. We compare and contrast the observed geomechanical behavior of each site, with particular focus on the risks to storage security posed by geomechanical deformation. At Sleipner, the large, high-permeability storage aquifer has experienced little pore pressure increase over 15 y of injection, implying little possibility of geomechanical deformation. At Weyburn, 45 y of oil production has depleted pore pressures before increases associated with CO2 injection. The long history of the field has led to complicated, sometimes nonintuitive geomechanical deformation. At In Salah, injection into the water leg of a gas reservoir has increased pore pressures, leading to uplift and substantial microseismic activity. The differences in the geomechanical responses of these sites emphasize the need for systematic geomechanical appraisal before injection in any potential storage site.

Surface thermodynamic homeostasis of salivary conditioning films through polar-apolar layering.

Salivary conditioning films (SCFs) form on all surfaces exposed to the oral cavity and control diverse oral surface phenomena. Oral chemotherapeutics and dietary components present perturbations to SCFs. Here we determine the surface energetics of SCFs through contact angle measurements with various liquids on SCFs following perturbations with a variety of chemotherapeutics as well as after renewed SCF formation. Sixteen-hour SCFs on polished enamel surfaces were treated with a variety of chemotherapeutics, including toothpastes and mouthrinses. After treatment with chemotherapeutics, a SCF was applied again for 3 h. Contact angles with four different liquids on untreated and treated SCF-coated enamel surfaces were measured and surface free energies were calculated. Perturbations either caused the SCF to become more polar or more apolar, but in all cases, renewed SCF formation compensated these changes. Thus, a polar SCF attracts different salivary proteins or adsorbs proteins in a different conformation to create a more apolar SCF surface after renewed SCF formation and vice versa for apolar SCFs. This polar-apolar layering in SCF formation presents a powerful mechanism in the oral cavity to maintain surface thermodynamic homeostasis--defining oral surface properties within a narrow, biological range and influencing chemotherapeutic strategies. Surface chemical changes brought about by dietary or chemotherapeutic perturbations to SCFs make it more polar or apolar, but new SCFs are rapidly formed compensating for changes in surface energetics.

A comparison of growth, photosynthetic capacity and water stress in Eucalyptus globulus coppice regrowth and seedlings during early development.

Eucalyptus globulus Labill., a globally significant plantation species, is grown commercially in a multiple rotation framework. Second and subsequent crops of E. globulus may be established either by allowing the cut stumps to resprout (commonly referred to as coppice) or by replanting a new crop of seedlings. Currently, long-term growth data comparing coppice and seedling productivity in second or later rotations in southern Australia is limited. The capacity to predict productivity using these tools is dependent on an understanding of the physiology of seedlings and coppice in response to light, water and nutrient supply. In this study, we compared the intrinsic (independent of the immediate environment) and native (dependent on the immediate environment) physiology of E. globulus coppice and second-generation seedlings during their early development in the field. Coppice not only grew more rapidly, but also used more water and drew on stored soil water to a depth of at least 4.5 m during the first 2 years of growth, whereas the seedlings only accessed the top 0.9 m of the soil profile. During the same period, there was no significant difference between coppice and seedlings in either their stomatal response to leaf-to-air vapour pressure difference (D) or intrinsic water-use efficiency; CO(2)- and light-saturated rates of photosynthesis were greater in seedlings than that in coppice as were the quantum yield of photosynthesis and total leaf chlorophyll content. Thus, at a leaf scale, seedlings are potentially more productive per unit leaf area than coppice during early development, but this is not realised under ambient conditions. The underlying cause of this inherent difference is discussed in the context of the allocation of resources to above- and below-ground organs during early development.

Surfactive and antibacterial activity of cetylpyridinium chloride formulations in vitro and in vivo.

AIM: To compare effects of three cetylpyridinium chloride (CPC) formulations with and without alcohol and Tween80 on physico-chemical properties of salivary pellicles, bacterial detachment in vitro and bacterial killing in vivo. MATERIAL AND METHODS: Adsorption of CPC to salivary pellicles in vitro was studied using X-ray photoelectron spectroscopy and water contact angle measurements. Adhesion and detachment of a co-adhering bacterial pair was determined in vitro using a flow chamber. Killing was evaluated after live/dead staining after acute single use in vivo on 24- and 72-h-old plaques after 2-week continuous use. RESULTS: The most pronounced effects on pellicle surface chemistry and hydrophobicity were observed after treatment with the alcohol-free formulation, while the pellicle thickness was not affected by any of the formulations. All CPC formulations detached up to 33% of the co-adhering pair from pellicle surfaces. Bacterial aggregate sizes during de novo deposition were enhanced after treatment with the alcohol-free formulation. Immediate and sustained killing in 24 and 72 h plaques after in vivo, acute single use as well as after 2-week continuous use were highest for the alcohol-free formulation. CONCLUSIONS: CPC bioavailability in a formulation without alcohol and Tween80 could be demonstrated through measures of pellicle surface properties and bacterial interactions in vitro as well as bacteriocidal actions on oral biofilms in vivo.

Efficacy and mechanisms of non-antibacterial, chemical plaque control by dentifrices--an in vitro study.

OBJECTIVES: The provision of antiplaque benefits to dentifrices assists patients in improving hygiene and reducing susceptibility to gingivitis and caries. Chemical plaque control involves different mechanisms and is mostly associated with antibacterial effects, but also includes effects on pellicle surface chemistry to improve cleansing or discourage renewed plaque formation. It is the aim of this paper to analyze in vitro detachment of co-aggregating oral actinomyces and streptococci from pellicle surfaces by dentifrice supernates and to study subsequent de novo streptococcal deposition. METHODS: Detachment by dentifrices of a co-adhering bacterial pair was studied in the parallel plate flow chamber on a 16 h pellicle coated surface. After detachment by perfusing the chamber with a dentifrice, re-deposition was initiated by flowing with a fresh streptococcal suspension. The dentifrices included both a regular, SLS-fluoride based formulation as well a pyrophosphate, anticalculus and antimicrobial formulations. RESULTS: All dentifrice supernates containing SLS were effective in detaching co-adhering bacteria from pellicles surfaces, except in combination with SnF(2). When hexametaphosphate was added immediate detachment was relatively low, but continued even during re-deposition. The re-deposition of streptococci after detachment by other, NaF containing dentifrices involved relatively few large aggregates, presumably because fluoride was able to block bi-dentate calcium binding sites on the bacterial cell surfaces, mediating co-adhesion. When pyrophosphate was present in addition to NaF, re-deposition involved significantly more large aggregates, likely because pyrophosphate served as a bi-dentate bridge between calcium bound on the bacterial cell surfaces. CONCLUSION: Commercially available dentifrice formulations differ in their ability to stimulate bacterial detachment from pellicles and dependent on their composition yield the formation of large co-adhering aggregates of actinomyces and streptococci in de novo deposition.

Relationships among resistances to fusarium and Aspergillus ear rots and contamination by fumonisin and aflatoxin in maize.

ABSTRACT Fusarium verticillioides, F. proliferatum, and Aspergillus flavus cause ear rots of maize and contaminate the grain with mycotoxins (fumonisin or aflatoxin). The objective of this study was to investigate the relationships between resistance to Fusarium and Aspergillus ear rots and fumonisin and aflatoxin contamination. Based on a previous study of 143 recombinant inbred lines from the cross NC300 x B104, 24 lines with the highest and 24 lines with the lowest mean fumonisin concentration were selected for further evaluation. Paired plots of each line were inoculated with F. verticillioides and F. proliferatum or with A. flavus in replicated trials in 2004 and 2005 in Clayton, NC, and College Station, TX. The low-fumonisin group had significantly lower levels of fumonisin, aflatoxin, and Fusarium and Aspergillus ear rots. Across year-location environments, all four traits were significantly correlated; the genotypic correlation (r(G)) ranged from r(G) = 0.88 (aflatoxin and Aspergillus ear rot) to r(G) = 0.99 (Fusarium and Aspergillus ear rots). Quantitative trait loci (QTLs) were identified and their effects estimated. Two QTLs affected both toxin concentrations, one QTL affected both ear rots, and one QTL affected Aspergillus and Fusarium rots and fumonisin. These results suggest that at least some of the genes involved in resistance to ear rots and mycotoxin contamination are identical or genetically linked.

Adoptive cell transfer therapy following non-myeloablative but lymphodepleting chemotherapy for the treatment of patients with refractory metastatic melanoma.

PURPOSE: We investigated the combination of lymphodepleting chemotherapy followed by the adoptive transfer of autologous tumor reactive lymphocytes for the treatment of patients with refractory metastatic melanoma. PATIENTS AND METHODS: Thirty-five patients with metastatic melanoma, all but one with disease refractory to treatment with high-dose interleukin (IL) -2 and many with progressive disease after chemotherapy, underwent lymphodepleting conditioning with two days of cyclophosphamide (60 mg/kg) followed by five days of fludarabine (25 mg/m(2)). On the day following the final dose of fludarabine, all patients received cell infusion with autologous tumor-reactive, rapidly expanded tumor infiltrating lymphocyte cultures and high-dose IL-2 therapy. RESULTS: Eighteen (51%) of 35 treated patients experienced objective clinical responses including three ongoing complete responses and 15 partial responses with a mean duration of 11.5 +/- 2.2 months. Sites of regression included metastases to lung, liver, lymph nodes, brain, and cutaneous and subcutaneous tissues. Toxicities of treatment included the expected hematologic toxicities of chemotherapy including neutropenia, thrombocytopenia, and lymphopenia, the transient toxicities of high-dose IL-2 therapy, two patients who developed Pneumocystis pneumonia and one patient who developed an Epstein-Barr virus-related lymphoproliferation. CONCLUSION: Lymphodepleting chemotherapy followed by the transfer of highly avid antitumor lymphocytes can mediate significant tumor regression in heavily pretreated patients with IL-2 refractory metastatic melanoma.

On the wettability of soft tissues in the human oral cavity.

In this study, the wettability of gingival surfaces in the human oral cavity was assessed by the measurement of intra-oral water contact angles. Intra-oral water contacts angles were measured in the morning prior to tooth brushing, immediately after tooth brushing and prior to and after lunch in order to reveal the influences of toothpaste and dietary components on the wettability of the gingiva. Within a group of 10 volunteers, gingival surfaces were hydrophobic, with water contact angles ranging from 72 to 79 degrees, which is high as compared with other soft tissues in the human body. Gingival contact angles were not affected by most commercial toothpastes involved in this study, but decreased slightly to 65 degrees after brushing with a hexametaphosphate containing toothpaste. During the day, however, the hydrophobicity readily recovered and after lunch contact angles on the gingival surfaces were higher than early in the morning, now ranging from 76 to 83 degrees. It is generally known that soft tissues in the human body involved in adsorptive and exchange functions and requiring lubrication are more hydrophilic than tissues with more protective functions. This study shows that gingival surfaces classify as the most hydrophobic soft tissue in the human body, attesting to their important protective role in the oral cavity.

Tree roots: conduits for deep recharge of soil water.

In previous work, we provided evidence from sap flow measurements that when root systems span soil layers of different moisture content, water is redistributed by roots in the direction of the difference in water potential. In addition to the phenomenon termed "hydraulic lift", where water is redistributed from depth to dry topsoil, the process of "hydraulic redistribution" includes downward transfer of water when the surface layers of soils with low permeability become wet after rainfall. In this paper, we support our previous findings with evidence from measurements of soil water and estimate the quantities of water transferred to depth following rain. Amounts of water stored at depth are not likely to be significant for drought avoidance by plants. However, downward transfer of water may be important to plant establishment and the reduction of waterlogging in certain soil types.

Leaf water relations and stomatal behavior of four allopatric Eucalyptus species planted in Mediterranean southwestern Australia.

In 1986, four allopatric Eucalyptus species (E. camaldulensis Dehnh, E. saligna Smith, E. leucoxylon F. Muell and E. platypus Hook.) were planted together in a 480-mm rainfall zone, in 8-m wide contour belts as part of a plan to minimize waterlogging and secondary salinization. Throughout 1997, 1998 and 1999, there was significant inter-specific variation in predawn leaf water potential (Psi(pd)); however, maximum stomatal conductance (g(sm)) only differed significantly between species in mid to late summer. Relationships between g(sm) and Psi(pd) were significant and showed that stomata of E. camaldulensis were significantly more sensitive to Psi(pd), and presumably soil water potential, than stomata of E. leucoxylon or E. platypus. When applied to the Psi(pd) data, these relationships predicted that g(sm), and by inference transpiration, varied much less between species than Psi(pd). Diurnal measurements throughout the season confirmed this prediction, and showed that E. camaldulensis and E. saligna avoided drought by gaining access to deeper water, whereas E. leucoxylon and E. platypus maintained greater g(sm) at a given water stress than E. camaldulensis or E. saligna. Osmotic potentials measured after rehydration and water release curves of the leaves indicated that different mechanisms accounted for the apparent drought tolerance of E. leucoxylon and E. platypus. In summer, E. leucoxylon reduced osmotic potential at full and zero turgor by similar amounts compared with winter. In summer, E. platypus had a significantly lower bulk elastic modulus and relative water content at turgor loss point than E. camaldulensis, E. saligna or E. leucoxylon. This elastic adjustment resulted in a larger difference between osmotic potential at full and zero turgor in summer than in winter. The inherently low osmotic potential in E. leucoxylon and elastic adjustment in E. platypus resulted in turgor loss at a similar and significantly lower water potential than in E. camaldulensis or E. saligna. These results have implications for species selection for planting to manage groundwater recharge in areas prone to waterlogging and secondary salinization.