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At least 73 records · Page 4Linked to original sources
PubMed2005

Evidence for mutualist limitation: the impacts of conspecific density on the mycorrhizal inoculum potential of woodland soils.

The ability of seedlings to establish can depend on the availability of appropriate mycorrhizal fungal inoculum. The possibility that mycorrhizal mutualists limit the distribution of seedlings may depend on the prevalence of the plant hosts that form the same type of mycorrhizal association as the target seedling species and thus provide inoculum. We tested this hypothesis by measuring ectomycorrhizal (EM) fine root distribution and conducting an EM inoculum potential bioassay along a gradient of EM host density in a pinyon-juniper woodland where pinyon is the only EM fungal host while juniper and other plant species are hosts for arbuscular mycorrhizal (AM) fungi. We found that pinyon fine roots were significantly less abundant than juniper roots both in areas dominated aboveground by juniper and in areas where pinyon and juniper were co-dominant. Pinyon seedlings establishing in pinyon-juniper zones are thus more likely to encounter AM than EM fungi. Our bioassay confirmed this result. Pinyon seedlings were six times less likely to be colonized by EM fungi when grown in soil from juniper-dominated zones than in soil from either pinyon-juniper or pinyon zones. Levels of EM colonization were also reduced in seedlings grown in juniper-zone soil. Preliminary analyses indicate that EM community composition varied among sites. These results are important because recent droughts have caused massive mortality of mature pinyons resulting in a shift towards juniper-dominated stands. Lack of EM inoculum in these stands could reduce the ability of pinyon seedlings to re-colonize sites of high pinyon mortality, leading to long-term vegetation shifts.

Arizona↗
PubMed2005

Woodrat (Neotoma) herbivores maintain nitrogen balance on a low-nitrogen, high-phenolic forage, Juniperus monosperma.

The acquisition of adequate quantities of nitrogen is a challenge for herbivorous vertebrates because many plants are in low nitrogen and contain secondary metabolites that reduce nitrogen digestibility. To investigate whether herbivores maintain nitrogen balance on plant diets low in nitrogen and high in secondary compounds, we studied the effect of juniper (Juniperus monosperma) ingestion on the nitrogen balance of two species of herbivorous woodrats (Neotoma stephensi and N. albigula). These woodrat species feed on the foliage of juniper: N. stephensi is a juniper specialist, whereas N. albigula is a generalist that incorporates some juniper in its diet. Based on the nitrogen contents of the natural diets of these woodrats, we predicted that the generalist would be in negative nitrogen balance on a juniper diet whereas the specialist would not be affected. We found that both species of woodrat had low-nitrogen requirements (334.2 mg N/kg0.75/day) and that a diet of 50% juniper did not result in negative nitrogen balance for either species. However, excretion patterns of nitrogen were altered; on the 50% juniper diet, fecal nitrogen losses increased approximately 38% and urinary nitrogen losses were half that of the control diet. The results suggest that absorption and detoxification of juniper secondary compounds may be more important for restricting juniper intake by the generalist than nitrogen imbalance.

Analysis of Variance↗
PubMed2005

Cadmium ion sorption onto lignocellulosic biosorbent modified by sulfonation: the origin of sorption capacity improvement.

Juniper (Juniperus monosperma), a small-diameter underutilized material, has been studied as a lignocellulosic biosorbent for removing heavy metals from water. In this study, juniper wood was modified by sulfonation to enhance sorption capacity for cadmium in water. The origin of the enhancement was investigated by observing the sorption behaviors and the change in surface functional group concentrations. Cadmium sorption by all juniper wood biosorbents studied was fast and the sorption capacity decreased with decreasing pH, similar to results found for other biosorbents. Sulfonated juniper was found to have at least twice the sorption capacity for cadmium removal from water compared to that of untreated juniper, though the sorption capacity increased with increasing pH. A slight increase in carboxylate content after sulfonation was likely responsible for a small portion of the enhancement. Elemental analysis showed an increase in sulfur content after sulfonation. Diffuse reflectance infrared Fourier transform (DRIFT) spectra showed a decrease in the band at 1660 cm(-1) in the range of carbonyl groups as a result of sulfonation. This indicates that coniferaldehyde groups in the lignin of juniper wood corresponding to this band were substituted into sulfonic acid groups after sulfonation. This interpretation was supported by both the color forming reaction with phloroglucinol-hydrochloric acid and the reaction mechanisms from the acid sulfite pulping process. Consequently, the enhancement of cadmium sorption capacity of juniper wood by sulfonation mainly originated from the production of sulfonic acid groups, which are binding sites for heavy metals.

Acrolein↗
PubMed1999

Gas exchange and carbon isotope discrimination of Juniperus osteosperma and Juniperus occidentalis across environmental gradients in the Great Basin of western North America.

We determined how ecophysiological characteristics of two juniper species, Juniperus occidentalis Hook. (western juniper) and Juniperus osteosperma (Torr.) Little (Utah juniper), changed along altitudinal and regional environmental gradients in the Great Basin of western North America. We obtained diurnal measurements of leaf gas exchange and xylem water potential (Psi) from plants at a low and a high altitude site within each of six mountain ranges during fall 1994, spring, summer, and fall 1995, and summer 1996. We also determined carbon isotope composition (delta(13)C) of leaf cellulose produced during the 1995 growing season. Overall, leaf gas exchange, Psi and delta(13)C did not differ significantly between species. Differences in daily (A(d)) and season-long (A(s)) carbon assimilation among mountain ranges suggested two groupings-a group of northern ranges and a group of southern ranges. Each group contained one mountain range with J. occidentalis and two with J. osteosperma. Differences in carbon assimilation based on this grouping were associated with two findings: (1) conductance of CO(2) from substomatal cavities to the site of carboxylation (g(m)) for junipers in the northern ranges averaged almost twice that of junipers in the southern ranges; and (2) physiological shifts occurred such that A(d) of junipers in the northern ranges was influenced more by Psi(pd), whereas A(d) of junipers in the southern ranges was influenced more by leaf temperature. Mean delta(13)C over all trees at a site was significantly correlated with annual precipitation. Significant differences in A(d) occurred between altitudes, but these differences were associated with differences in the timing of optimum leaf temperature for photosynthesis rather than with physiological acclimation to temperature, irradiance, or Psi. Most gas exchange parameters (e.g., assimilation, transpiration, stomatal conductance, and water use efficiency) varied seasonally, and the seasonal differences were strongly influenced by water stress.

Journal Article↗
PubMed1994

Transmission of food preference in the rabbit: the means of information transfer.

Rabbit pups raised by mothers fed different diets during pregnancy and lactation show a clear preference for the diet of their mother at weaning. By supplementing does' lab chow diet with aromatic juniper berries, the present study aimed to investigate the relative importance of 1) fecal pellets deposited by the mother in the nest, 2) prenatal experience in utero, and 3) contact with the mother during nursing in determining pups' later food preference. The three means of transmission were found to be equally effective. Thus, pups from normally fed does raised with fecal pellets from juniper-fed mothers, pups from juniper-fed mothers cross-fostered to normally fed does immediately after birth, and pups of normally fed mothers nursed by juniper-fed does all showed as strong a preference for juniper as pups raised by juniper-fed mothers exclusively. Such apparent redundancy may not only help insure that less aromatic substances or substances transmitted differentially by these routes are learned, but also that pups can acquire a preference for a variety of foods eaten by their mother at different times.

Animals↗
PubMed2001

Antimicrobial activity of some Pacific Northwest woods against anaerobic bacteria and yeast.

Extracts of woods commonly used for animal bedding were tested for antimicrobial activity. Essential oils from Alaska cedar (Chamaecyparis nootkatensis), western juniper (Juniperus occidentalis) and old growth Douglas fir (Pseudotsuga menziesii) as well as methanol extracts of wood from these trees plus western red cedar (Thuja plicata) and ponderosa pine (Pinus ponderosa) were tested for antimicrobial activity against anaerobic bacteria and yeast. The test microbes included Fusobacterium necrophorum, Clostridium perfringens, Actinomyces bovis and Candida albicans which are common to foot diseases and other infections in animals. The essential oils and methanol extracts were tested using a standardized broth assay. Only extracts of Alaska cedar and western juniper showed significant antimicrobial activity against each of the microbes tested. The essential oil of Douglas fir did show antimicrobial activity against A. bovis at the concentrations tested. The methanol extracts of the heartwood of Douglas fir and the sapwood of ponderosa pine showed no antimicrobial activity. The major chemical components of western juniper (cedrol and alpha- and beta-cedrene) and Alaska cedar (nootkatin) were also tested. In western juniper, alpha- and beta-cedrene were found to be active components. Nootkatin showed activity only against C. albicans. The inhibitory activity in Alaska cedar oil was high enough to justify further efforts to define the other chemical components responsible for the antimicrobial activity.

Anti-Bacterial Agents↗
PubMed2006

Is alpha-pinene a substrate for permeability-glycoprotein in wood rats?

alpha-Pinene is the dominant monoterpene in Juniperus monosperma. Wood rat species in the genus Neotoma that consume J. monosperma vary in their inclusion of it in their wild diet and in their tolerance of whole J. monosperma or alpha-pinene in laboratory feeding trials. A proposed mechanism for variable tolerance is a difference in absorption of alpha-pinene from the small intestine that is mediated by the intestinal transporter permeability glycoprotein (Pgp). To determine if alpha-pinene is a Pgp substrate, we tested whether it can competitively inhibit Pgp and thereby increase the accumulation of a known Pgp substrate (digoxin) in (1) everted sleeves of small intestine from Neotoma stephensi, a juniper specialist, N. albigula, a sympatric generalist that consumes juniper, N. cinerea, a more distantly related generalist, and Sprague-Dawley rats, and (2) in Caco-2 cells that over express Pgp. We also measured Pgp ATPase phosphate production in transfected insect membrane vesicles exposed to alpha-pinene. We found no significant increase in digoxin accumulation with competitive inhibition experiments, and no increase in phosphate production with transfected membranes, at any concentration of alpha-pinene up to 100 muM. To test whether other compounds in juniper affect Pgp activity, we acclimated five N. stephensi to a juniper diet for 5 d, but found no significant effect compared to animals on control diet. Our data suggest that alpha-pinene is not a Pgp substrate.

Animals↗
PubMed2001

Final report on the safety assessment of Juniperus communis Extract, Juniperus oxycedrus Extract, Juniperus oxycedrus Tar, Juniperus phoenicea extract, and Juniperus virginiana Extract.

The common juniper is a tree that grows in Europe, Asia, and North America. The ripe fruit of Juniperus communis and Juniperus oxycedrus is alcohol extracted to produce Juniperus Communis Extract and Juniperus Oxycedrus Extract, respectively. Juniperus Oxycedrus Tar is the volatile oil from the wood of J. oxycedrus. Juniperus Phoenicea Extract comes from the gum of Juniperus phoenicea, and Juniperus Virginiana Extract is extracted from the wood of Juniperus virginiana. Although Juniperus Oxycedrus Tar is produced as a by-product of distillation, no information was available on the manufacturing process for any of the Extracts. Oils derived from these varieties of juniper are used solely as fragrance ingredients; they are commonly produced using steam distillation of the source material, but it is not known if that procedure is used to produce extracts. One report does state that the chemical composition of Juniper Communis Oil and Juniperus Communis Extract is similar, each containing a wide variety of terpenoids and aromatic compounds, with the occasional aliphatic alcohols and aldehydes, and, more rarely, alkanes. The principle component of Juniperus Oxycedrus Tar is cadinene, a sesquiterpene, but cresol and guaiacol are also found. No data were available, however, indicating the extent to which there would be variations in composition that may occur as a result of extraction differences or any other factor such as plant growth conditions. Information on the composition of the other ingredients was not available. All of the Extracts function as biological additives in cosmetic formulations, and Juniperus Oxycedrus Tar is used as a hair-conditioning agent and a fragrance component. Most of the available safety test data are from studies using oils derived from the various varieties of juniper. Because of the expected similarity in composition to the extract, these data were considered. Acute studies using animals show little toxicity of the oil or tar. The oils derived from J. communis and J. virginiana and Juniperus Oxycedrus Tar were not skin irritants in animals. The oil from J. virginiana was not a sensitizer, and the oil from J. communis was not phototoxic in animal tests. Juniperus Oxycedrus Tar was genotoxic in several assays. No genotoxicity data were available for any of the extracts. Juniperus Communis Extract did affect fertility and was abortifacient in studies using albino rats. Clinical tests showed no evidence of irritation or sensitization with any of the tested oils, but some evidence of sensitization to the tar. These data were not considered sufficient to assess the safety of these ingredients. Additional data needs include current concentration of use data; function in cosmetics; methods of manufacturing and impurities data, especially pesticides; ultraviolet (UV) absorption data; if absorption occurs in the UVA or UVB range, photosensitization data are needed; dermal reproductive/developmental toxicity data (to include determination of a no-effect level); two genotoxicity assays (one in a mammalian system) for each extract; if positive, a 2-year dermal carcinogenicity assay performed using National Toxicology Program (NTP) methods is needed; a 2-year dermal carcinogenicity assay performed using NTP methods on Juniperus Oxycedrus Tar; and irritation and sensitization data on each extract and the tar (these data are needed because the available data on the oils cannot be extrapolated). Until these data are available, it is concluded that the available data are insufficient to support the safety of these ingredients in cosmetic formulations.

Abortion, Spontaneous↗
PubMed2006

Secondary outcomes of a pilot randomized trial of azithromycin treatment for asthma.

OBJECTIVES: The respiratory pathogen Chlamydia pneumoniae (C. pneumoniae) produces acute and chronic lung infections and is associated with asthma. Evidence for effectiveness of antichlamydial antibiotics in asthma is limited. The primary objective of this pilot study was to investigate the feasibility of performing an asthma clinical trial in practice settings where most asthma is encountered and managed. The secondary objectives were to investigate (1) whether azithromycin treatment would affect any asthma outcomes and (2) whether C. pneumoniae serology would be related to outcomes. This report presents the secondary results. DESIGN: Randomized, placebo-controlled, blinded (participants, physicians, study personnel, data analysts), allocation-concealed parallel group clinical trial. SETTING: Community-based health-care settings located in four states and one Canadian province. PARTICIPANTS: Adults with stable, persistent asthma. INTERVENTIONS: Azithromycin (six weekly doses) or identical matching placebo, plus usual community care. OUTCOME MEASURES: Juniper Asthma Quality of Life Questionnaire (Juniper AQLQ), symptom, and medication changes from baseline (pretreatment) to 3 mo posttreatment (follow-up); C. pneumoniae IgG and IgA antibodies at baseline and follow-up. RESULTS: Juniper AQLQ improved by 0.25 (95% confidence interval; -0.3, 0.8) units, overall asthma symptoms improved by 0.68 (0.1, 1.3) units, and rescue inhaler use decreased by 0.59 (-0.5, 1.6) daily administrations in azithromycin-treated compared to placebo-treated participants. Baseline IgA antibodies were positively associated with worsening overall asthma symptoms at follow-up (p = 0.04), but IgG was not (p = 0.63). Overall asthma symptom improvement attributable to azithromycin was 28% in high IgA participants versus 12% in low IgA participants (p for interaction = 0.27). CONCLUSIONS: Azithromycin did not improve Juniper AQLQ but appeared to improve overall asthma symptoms. Larger community-based trials of antichlamydial antibiotics for asthma are warranted.

Journal Article↗
PubMed1990

Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice.

The effects on glucose homeostasis of eleven plants used as traditional treatments for diabetes mellitus were evaluated in normal and streptozotocin diabetic mice. Dried leaves of agrimony (Agrimonia eupatoria), alfalfa (Medicago sativa), blackberry (Rubus fructicosus), celandine (Chelidonium majus), eucalyptus (Eucalyptus globulus), lady's mantle (Alchemilla vulgaris), and lily of the valley (Convallaria majalis); seeds of coriander (Coriandrum sativum); dried berries of juniper (Juniperus communis); bulbs of garlic (Allium sativum) and roots of liquorice (Glycyrhizza glabra) were studied. Each plant material was supplied in the diet (6.25% by weight) and some plants were additionally supplied as decoctions or infusions (1 g/400 ml) in place of drinking water to coincide with the traditional method of preparation. Food and fluid intake, body weight gain, plasma glucose and insulin concentrations in normal mice were not altered by 12 days of treatment with any of the plants. After administration of streptozotocin (200 mg/kg i.p.) on day 12 the development of hyperphagia, polydipsia, body weight loss, hyperglycaemia and hypoinsulinaemia were not affected by blackberry, celandine, lady's mantle or lily of the valley. Garlic and liquorice reduced the hyperphagia and polydipsia but did not significantly alter the hyperglycaemia or hypoinsulinaemia. Treatment with agrimony, alfalfa, coriander, eucalyptus and juniper reduced the level of hyperglycaemia during the development of streptozotocin diabetes. This was associated with reduced polydipsia (except coriander) and a reduced rate of body weight loss (except agrimony). Alfalfa initially countered the hypoinsulinaemic effect of streptozotocin, but the other treatments did not affect the fall in plasma insulin. The results suggest that certain traditional plant treatments for diabetes, namely agrimony, alfalfa, coriander, eucalyptus and juniper, can retard the development of streptozotocin diabetes in mice.

Animals↗
PubMed2004

Removal of phosphorus from water using lignocellulosic material modified with iron species from acid mine drainage.

Lignocellulosic biosorbents, including juniper fiber, show promise as sorbents for removing pollutants from wastewater run-off because of their low cost. In this study, juniper fiber modified with iron species from acid mine drainage (AMD) was tested for its capacity to remove phosphorus from water compared to unmodified juniper fiber. In batch tests, the maximum adsorbate loading (Qmax) of phosphorus onto the modified adsorbent was 1.83 mg g(-1) at pH 4.0, obtained by fitting the isotherm results to the Langmuir isotherm model. This value is similar to the sorption capacity of other conventional adsorbents such as goethite, which implies that the modified lignocellulosic material would be effective as a sorbent for removing phosphorus from water. In the kinetic test, the pseudo-second order kinetic model fitted well the sorption of phosphorus onto the modified filter medium, showing the kinetic constant (k) of 8.09 x 10(-2) g(mg min)(-1) at initial phosphorus concentration of 10 mg l(-1).

Cellulose↗
PubMed2004

Barriers to sympatry between avian sibling species (Paridae: Baeolophus) in local secondary contact.

Range limits and secondary contact zones often occur at ecotones between major associations of habitat and climate. Therefore, understanding processes that limit sympatry between species in such areas provides an important framework for testing biogeographic and evolutionary hypotheses. Theoretical and empirical work has shown that the evolution of species borders is influenced by a complexity of factors, including gene flow from central to peripheral populations and the ability of species to adapt locally to environmental conditions. However, few studies have used bioclimatic models, combined with molecular and morphological data, to predict geographic range limits in the context of gene flow across a secondary contact zone. In this study, I applied these methods to test specific hypotheses about barriers to sympatry between closely related species where they approach and contact each other. Specifically, I examined the importance of historical isolation, local adaptation, and symmetry of gene flow in limiting sympatry and range expansion of ecologically distinct species across environmental gradients. Molecular (mitochondrial DNA, allozymes), morphological, and bioclimatic data were obtained for two avian sibling species (Baeolophus inornatus and B. ridgwayi) that exist in recent, narrow secondary contact in northern California. These species are broadly allopatric and occupy rangewide associations of oak and pinyon-juniper woodlands, respectively, although B. inornatus also inhabits mixed or juniper woodlands locally. Patterns of molecular variation generally were congruent with morphological and bioclimatic data, and support prior evidence for a history of isolation, adaptation, and divergence in distinctive, species-specific vegetation-climate associations. However, molecular and morphological clines fall east of the limit of oaks, and individuals of B. inornatus in this juniper-associated contact zone experience bioclimates that are more similar to B. ridgwayi than to B. inornatus in oak habitat. Thus, B. inornatus is able to adapt and expand locally into the range of its close relative, but not vice versa. These data support the hypothesis that gene flow is asymmetrical where peripheral populations meet at range boundaries. Physiological differences between species may play an important role in influencing these patterns. Empirical studies that highlight the importance of local adaptation and patterns of gene flow in which closely related species contact across ecotones are central to understanding limits on geographic ranges, sympatry, and introgression-a cornerstone of biogeographic and speciation theory.

Analysis of Variance↗