Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers

Aim

Climate change is affecting the distribution of species and subsequent biotic interactions, including hybridization potential. The imperiled Golden-winged Warbler (GWWA) competes and hybridizes with the Blue-winged Warbler (BWWA), which may threaten the persistence of GWWA due to introgression. We examined how climate change is likely to alter the breeding distributions and potential for hybridization between GWWA and BWWA.

Location

North America.

Methods

We used GWWA and BWWA occurrence data to model climatically suitable conditions under historical and future climate scenarios. Models were parameterized with 13 bioclimatic variables and 3 topographic variables. Using ensemble modeling, we estimated historical and modern distributions, as well as a projected distribution under six future climate scenarios. We quantified breeding distribution area, the position of and amount of overlap between GWWA and BWWA distributions under each climate scenario. We summarized the top explanatory variables in our model to predict environmental parameters of the distributions under future climate scenarios relative to historical climate.

Results

GWWA and BWWA distributions are projected to substantially change under future climate scenarios. GWWA are projected to undergo the greatest change; the area of climatically suitable breeding season conditions is expected to shift north to northwest; and range contraction is predicted in five out of six future climate scenarios. Climatically suitable conditions for BWWA decreased in four of the six future climate scenarios, while the distribution is projected to shift east. A reduction in overlapping distributions for GWWA and BWWA is projected under all six future climate scenarios.

Main Conclusions

Climate change is expected to substantially alter the area of climatically suitable conditions for GWWA and BWWA, with the southern portion of the current breeding ranges likely to become climatically unsuitable. However, interactions between BWWA and GWWA are expected to decline with the decrease in overlapping habitat, which may reduce the risk of genetic introgression.     

Effect of heat treatment on Listeria monocytogenes and Gram-negative bacteria in sheep, cow and goat milks

Sheep milk, compared with cow and goat milk, had a protective effect on Gram-negative bacteria and Listeria spp. heated at 65°C in a test-tube method. This effect was not solely due to fat content as cow milk artificially reconstituted to 10% homologous fat was not as protective. Listeria monocytogenes in whole sheep, cow and goat milks at an inoculum level of 1 times 10⁶ cfu ml^-1 was heated at 68°C for 15 s in the plate pasteurizer and survival was only detected in whole sheep milk after heating. Whole sheep, cow and goat milks containing high levels of L. monocytogenes (1 times 10⁶ cfu ml^-1) could not survive the current HTST plate pasteurization protocol.     

The influence of religious affiliation on surname repetition in marriages in Tiszaszalka, Hungary.

The repeated-pairs of surnames in marriages (RP) approach is applied to the population of Tiszaszalka in north-eastern Hungary. The results indicate that: (1) lineage-like behaviour in mate choice results in population subdivision in both the Catholics and the Protestants of the village; (2) unlike in some other Tiszahat villages, the isonymous and the repeating unions in Tiszaszalka occur in different lineages so, in neither of these subpopulations are isonymous and repeating unions monopolised by a few lineages; (3) religious affilitation influences the mating structure of the population as measured by RP summary scores.     

Phospholipases Involved in Activation of the Neutrophil NADPH Oxidase

Stimulation of neutrophils with a variety of stimuli can result in the activation of phospholipases A₂, C, or D with the resultant hydrolysis of plasma membrane phospholipids and the formation of important second messenger molecules. In the neutrophil, the activities of these phospholipases have been implicated in the processes of both stimulating and maintaining oxidase activation. In this review, some of the methods currently used to measure the products of phospholipase activation in the neutrophil are described, along with the possible role of their products in reactive oxidant production by the neutrophil NADPH oxidase.     

Low‐dose linearity: The rule or the exception?

In 1976, Crump, Hoel, Langley, and Peto described how almost any dose‐response relationship for carcinogens becomes linear at low doses when background cancers are taken into account. This has been used, by the U.S. Environmental Protection Agency, USEPA, as partial justification for a regulatory posture that assumes low‐dose linearity, as is illustrated by a discussion of regulation of benzene as a carcinogen. The argument depends critically on the assumption that the pollutant and the background proceed by the same biological mechanism. In this paper we show that the same argument applies to noncancer end points also. We discuss the application to a number of situations: reduction in lung function and consequent increase in death rate due to (particulate) air pollution; reduction in IQ and hence (in extreme cases) mental deficiency due to radiation in utero; reduction of sperm count and hence increase in male infertility due to DBCP exposure. We conclude that, although the biological basis for the health effect response is different, in each case low‐dose linearity might arise from the same mathematical effect discussed by Crump et al. (1976). We then examine other situations and toxic end points where low‐dose linearity might apply by the same argument. We urge that biologists and chemists should concentrate efforts on comparing the biological and pharmacokinetic processes that apply to the pollutant and the background. Finally, we discuss some public policy implications of the possibility that low dose linearity may be the rule rather than the exception for environmental exposures.     

Transformation of carbon tetrachloride via sulfur and oxygen substitution by Pseudomonas sp. strain KC.

Pseudomonas sp. strain KC transforms carbon tetrachloride into carbon dioxide and nonvolatile products, without chloroform as an intermediate. To define the pathway for hydrolysis, nonvolatile products were analyzed. Condensation products containing the carbon atom of carbon tetrachloride as carbonyl and thioxo moieties were identified, indicating the intermediacy of phosgene and thiophosgene in the pathway.     

Isolation and sequencing of the replication region of Mycobacterium avium plasmid pLR7.

The Mycobacterium avium plasmid pLR7 is representative of a group of small plasmids that are common in isolates from AIDS patients with disseminated M. avium infections. Determination of the functions of these and other plasmids has been hampered by the lack of methods for genetic manipulation of M. avium. In this study, the region of pLR7 capable of replication was identified and sequenced. Fragments of pLR7 were cloned into a pUC18 derivative carrying a kanamycin resistance marker and introduced into a plasmid-free M. avium strain by electroporation. The origin of replication was located on a 1.8-kb PvuII-to-SmaI fragment. An open reading frame encoding a putative Rep protein was identified. Two other open reading frames were identified in this region. A shuttle vector, pMB351, was constructed with the pLR7 origin of replication, pUC18, and the kanamycin resistance gene from Tn5. This vector was successfully transformed into M. avium, Mycobacterium tuberculosis, and Mycobacterium bovis.     

Comparative capitular morphology and anatomy of Coreopsis L. and bidens L. (compositae), including a review of generic boundaries

The capitular and floral morphology and anatomy ofBidens L. andCoreopsis L. were studied. All the North American species ofCoreopsis were studied. Selected species ofBidens from North and South America andCoreopsis from South America were included. The results were compared with previous observations on African species ofBidens (incl.Coreopsis). Emphasis was given to character states of the ray florets, paleae, stylearm apices, outer phyllaries, achenes, and pollen grains. Some of the character states are unique features ofCoreopsis, e.g., globular and elongately conical receptacles, deltoid outer phyllaries, truncate and indistinctly 3–5-dentate, 3–4-lobed ray florets, narrowly spathulate paleae, subulate paleae with linear-filiform upper half, hairy and apically 3-cleft paleae, truncate, convex or shallowly conical stylearm apices with the sweeping hairs limited to the area above the stigmatic surfaces and the orbicular to circular achenes. The cylindric setaceous pappus bristles so commonly encountered inBidens are unknown inCoreopsis. The pappus bristles inCoreopsis are paleaceous but similar, though thicker ones are also found in African species ofBidens (incl.Coreopsis) with winged achenes. Twin-celled hairs (setulae) with differing degrees of wall thickness are found on the achenes ofCoreopsis sect.Pseudoagarista (Mexico and South America),Coreopsis sect.Pugiopappus (California), AfricanBidens with winged achenes (e.g.,B. prestinaria, B. macroptera) and some North AmericanBidens (e.g.,B. aristosa). Similar sclerotic parenchyma make up the achenial wings of species in both genera. These may be interpreted as homologous structures, indicating the underlying similarity of these taxa and their derivation from a common ancestral stock.