Host population effects on ectomycorrhizal fungi vary between low and high phosphorus soils of temperate rainforests.

Geographic distinctions in the affinity of tree populations for select ectomycorrhizal fungi (EMF) may occur where strong edaphic pressures act on fungal communities and their hosts. We examine this premise for Pseudotsuga menziesii var. menziesii of southwest British Columbia, using ten native seedlots collected from a range of mean annual precipitation (MAP), as a proxy for podzolization extent and phosphorus (P) deficiencies, and evaluated in contrasting low P and high P soils. After two growing seasons, seedling biomass in the high P soil dwarfed that of the low P soil, and better growth rates under high P were detected for populations from very dry and very wet origins. EMF communities on the high P soil displayed more symmetry among host populations than the low P soil (average community dissimilarity of 0.20% vs. 0.39%, respectively). Seedling foliar P% differed slightly but significantly in relation to MAP of origin. EMF species richness varied significantly among host populations but independently of climatic parameters. There were significant shifts in EMF species abundance related to seedlot MAP, particularly on the low P soil where nonlinear relationships were found for Wilcoxina mikolae, Hyaloscypha finlandica, and Rhizopogon villosulus. Despite efforts to enhance colonization by native fungi, the predominance of ruderal EMF species hindered a realistic evaluation of local adaptation among host-fungi populations. Nevertheless, the shifting affinity in taxa abundance and wider community disparity on low P soil reflected the potential for a consequential host genetic effect related to geographical patterns in P availability across temperate rainforests.

Species turnover (ß-diversity) in ectomycorrhizal fungi linked to NH4+ uptake capacity.

Ectomycorrhizal (EcM) fungal communities may be shaped by both deterministic and stochastic processes, potentially influencing ecosystem development and function. We evaluated community assembly processes for EcM fungi of Pseudotsuga menziesii among 12 sites up to 400 km apart in southwest British Columbia (Canada) by investigating species turnover (ß-diversity) in relation to soil nitrogen (N) availability and physical distance. We then examined functional traits for an N-related niche by quantifying net fluxes of NH4+, NO3- and protons on excised root tips from three contrasting sites using a microelectrode ion flux measurement system. EcM fungal communities were well aligned with soil N availability and pH, with no effect of site proximity (distance-decay curve) on species assemblages. Species turnover was significant (ß(1/2) = 1.48) along soil N gradients, with many more Tomentella species on high N than low N soils, in contrast to Cortinarius species. Ammonium uptake was greatest in the spring on the medium and rich sites and averaged over 190 nmol/m(2)/s for Tomentella species. The lowest uptake rates of NH4+ were by nonmycorrhizal roots of axenically grown seedlings (10 nmol/m(2)/s), followed by Cortinarius species (60 nmol/m(2)/s). EcM roots from all sites displayed only marginal uptake of nitrate (8.3 nmol/m(2)/s). These results suggest NH4+ uptake capacity is an important functional trait influencing the assembly of EcM fungal communities. The diversity of EcM fungal species across the region arguably provides critical belowground adaptations to organic and inorganic N supply that are integral to temperate rainforest ecology.

The effects of nutrition-induced abnormal food metabolism in the Southern Plains woodrat (Neotoma micropus): comparisons of variations of the Western diet.

We investigated the effects of several modifications of the Western diet on a medium-sized rodent, Neotoma micropus, that lives in the area of the wildland-urban interface. We conducted a laboratory study of the response of N. micropus to high fat-high fructose (HFHF), high fat-high sucrose (HFHS), high fat-low sugar (HFLSu) and control (low fat-low sugar) diets. We found a significant increase in hepatic lipid deposition and a significant decrease in podocytes in those animals that consumed the HFHF and HFLSu diets compared to those on the HFHS and control diets. We found no significant differences in Bowman's space or hepatic collagen formation. We predict that N. micropus in the wild, with access to anthropogenic resources, will show similar effects as a result of the consumption of anthropogenic resources.

Tree-ring δ15N as an indicator of nitrogen dynamics in stands with N2-fixing Alnus rubra.

Tree-ring δ15N may depict site-specific, long-term patterns in nitrogen (N) dynamics under N2-fixing species, but field trials with N2-fixing tree species are lacking and the relationship of temporal patterns in tree-ring δ15N to soil N dynamics is controversial. We examined whether the tree-ring δ15N of N2-fixing red alder (Alnus rubra Bong.) would mirror N accretion rates and δ15N of soils and whether the influence of alder-fixed N could be observed in the wood of a neighboring conifer. We sampled a 27-year-old replacement series trial on south-eastern Vancouver Island, with red alder and coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) planted in five proportions (0/100, 11/89, 25/75, 50/50 and 100/0) at a uniform stem density. An escalation in forest floor N content was evident with an increasing proportion of red alder, equivalent to a difference of ~750 kg N ha-1 between 100% Douglas-fir versus 100% alder. The forest floor horizon also had high δ15N values in treatments with more red alder. Red alder had a consistent quadratic fit in tree-ring δ15N over time, with a net increase of $\sim$1.5‰, on average, from initial values, followed by a plateau or slight decline. Douglas-fir tree-ring δ15N, in contrast, was largely unchanged over time (in three of four plots) but was significantly higher in the 50/50 mix. The minor differences in current leaf litter N content and δ15N between alder and Douglas-fir, coupled with declining growth in red alder, suggests the plateau or declining trend in alder tree-ring δ15N could coincide with lower N2-fixation rates, potentially by loss in alder vigor at canopy closure, or down-regulation via nitrate availability.

Refuges as a predictor of parasitoid diversity.

A central problem in ecology is predicting the diversity of communities. Insect parasitoids may encompass 20 percent of all insect species; hence, establishing the mechanisms that drive parasitoid species richness represents a major step in understanding the diversity of terrestrial communities. An assemblage model, based on population dynamic constructs, shows how the presence of refuges from parasitoid attack can generate diversity patterns that are in good accord with global data on structural protection from parasitism resulting from host feeding biology. This theory offers a simple ecological explanation for the range of diversities observed in real parasitoid assemblages. Predicting parasitoid diversity may be a realistic goal, at least for those systems in which the basic demography is well understood.

Refuge theory and biological control.

An important question in ecology is the extent to which populations and communities are governed by general rules. Recent developments in population dynamics theory have shown that hosts' refuges from their insect parasitoids predict parasitoid community richness patterns. Here, the refuge theory is extended to biological control, in which parasitoids are imported for the control of insect pests. Theory predicts, and data confirm, that the success of biological control is inversely related to the proportion of insects protected from parasitoid attack. Refuges therefore provide a general mechanism for interpreting ecological patterns at both the community level (their species diversity) and population level (their dynamics).

A comparison of ammonium, nitrate and proton net fluxes along seedling roots of Douglas-fir and lodgepole pine grown and measured with different inorganic nitrogen sources.

Significant spatial variability in NH4+, NO3- and H+ net fluxes was measured in roots of young seedlings of Douglas-fir (Pseudotsuga menziesii) and lodgepole pine (Pinus contorta) with ion-selective microelectrodes. Seedlings were grown with NH4+, NO3-, NH4NO3 or no nitrogen (N), and were measured in solutions containing one or both N ions, or no N in a full factorial design. Net NO3- and NH4+ uptake and H+ efflux were greater in Douglas-fir than lodgepole pine and in roots not exposed to N in pretreatment. In general, the rates of net NH4+ uptake were the same in the presence or absence of NO3-, and vice versa. The highest NO3- influx occurred 0-30 mm from the root apex in Douglas-fir and 0-10 mm from the apex in lodgepole pine. Net NH4+ flux was zero or negative (efflux) at Douglas-fir root tips, and the highest NH4+ influx occurred 5-20 mm from the root tip. Lodgepole pine had some NH4+ influx at the root tips, and the maximum net uptake 5 mm from the root tip. Net H+ efflux was greatest in the first 10 mm of roots of both species. This study demonstrates that nutrient uptake by conifer roots can vary significantly across different regions of the root, and indicates that ion flux profiles along the roots may be influenced by rates of root growth and maturation.

Improved blackwater disinfection using potentiodynamic methods with oxidized boron-doped diamond electrodes.

Electrochemical disinfection (ECD) has become an important blackwater disinfection technology. ECD is a promising solution for the 2 billion people without access to conventional sanitation practices and in areas deficient in basic utilities (e.g., sewers, electricity, waste treatment). Here, we report on the disinfection of blackwater using potential cycling compared to potentiostatic treatment methods in chloride-containing and chloride-free solutions of blackwater (i.e., untreated wastewater containing feces, urine, and flushwater from a toilet). Potentiodynamic treatment is demonstrated to improve disinfection energy efficiency of blackwater by 24% and 124% compared to static oxidation and reduction methods, respectively. The result is shown to be caused by electrochemical advanced oxidation processes (EAOP) and regeneration of sp2-surface-bonded carbon functional groups that serve the dual purpose of catalysts and adsorption sites of oxidant intermediates. Following 24 h electrolysis in blackwater, electrode fouling is shown to be minimized by the potential cycling method when compared to equivalent potentiostatic methods. The potential cycling current density is 40% higher than both the static oxidative and reductive methods. This work enhances the understanding of oxygen reduction catalysts using functionalized carbon materials and electrochemical disinfection anodes, both of which have the potential to bring a cost-effective, energy efficient, and practical solution to the problem of disinfecting blackwater.

HLA associations, microsatellite instability and epigenetic changes in thyroid lymphoma in Chinese.

In Chinese, autoimmune thyroid disease (AITD) is very common but lymphoma of the thyroid is a rare disease. Southern Chinese AITD is common in females and is strongly linked to the HLA haplotype A2B46DR9. We studied the HLA association, aberration p15, p16 and p73 promoter methylation and microsatellite instability in Chinese primary thyroid lymphoma patients to elucidate their relationship with AITD and the relationship between thyroid diffuse large cell lymphoma (DLCL) and marginal zone lymphomas (MZL). Despite a female preponderance (8:1) and the finding of cases with histological and immunological evidence of AITD, a significant HLA association was not found. MSI was absent, but aberrant promoter methylation was found in both thyroid MZL and DLCL and p73 methylation was unexpectedly common.

Family variation in nutritional and growth traits in Douglas-fir seedlings.

Nitrogen (N) uptake and utilization in seedlings of six full-sib families of coastal Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) known to differ in growth rate were assessed at the whole plant and root levels. Seedlings were grown in soil or aeroponically with high and low nutrient availability. Consistent family differences in growth rate and N utilization index were observed in both soil and aeroponic culture, and high-ranking families by these measures also had greater net N uptake in soil culture. Two of the three families found to be fast-growing in long-term field trials exhibited faster growth, higher N utilization indices and greater net N uptake at the seedling stage. Mean family net influx of ammonium (NH4+) and efflux of nitrate (NO3-) in the high- and low-nutrient treatments were significantly correlated with measures of mean family biomass. The high-nutrient availability treatment increased mean net fluxes of NH4+ and NO3- in roots. These results indicate that efficiency of nutrient uptake and utilization contribute to higher growth rates of trees. Nutrient-related traits should be considered in tree breeding programs, as the indications are that assessments may be made at an early stage.

Food and beverage product reformulation as a corporate political strategy.

Product reformulation- the process of altering a food or beverage product's recipe or composition to improve the product's health profile - is a prominent response to the obesity and noncommunicable disease epidemics in the U.S. To date, reformulation in the U.S. has been largely voluntary and initiated by actors within the food and beverage industry. Similar voluntary efforts by the tobacco and alcohol industry have been considered to be a mechanism of corporate political strategy to shape public health policies and decisions to suit commercial needs. We propose a taxonomy of food and beverage industry corporate political strategies that builds on the existing literature. We then analyzed the industry's responses to a 2014 U.S. government consultation on product reformulation, run as part of the process to define the 2015 Dietary Guidelines for Americans. We qualitatively coded the industry's responses for predominant narratives and framings around reformulation using a purposely-designed coding framework, and compared the results to the taxonomy. The food and beverage industry in the United States used a highly similar narrative around voluntary product reformulation in their consultation responses: that reformulation is "part of the solution" to obesity and NCDs, even though their products or industry are not large contributors to the problem, and that progress has been made despite reformulation posing significant technical challenges. This narrative and the frames used in the submissions illustrate the four categories of the taxonomy: participation in the policy process, influencing the framing of the nutrition policy debate, creating partnerships, and influencing the interpretation of evidence. These strategic uses of reformulation align with previous research on food and beverage corporate political strategy.

Harvey ras (H-ras) point mutations are induced by 4-nitroquinoline-1-oxide in murine oral squamous epithelia, while squamous cell carcinomas and loss of heterozygosity occur without additional exposure.

Tumorigenesis is a multistep genetic process requiring several somatic mutations for neoplastic transformation. These mutations appear to be sequential, random, and independent events. However, we find linked, nonrandom ras mutations occurring during 4-nitroquinoline-1-oxide-induced tumorigenesis months after exposure to the carcinogen had ceased. The carcinogen had been topically applied to the oral cavity of CBA mice for 4 to 16 weeks. Dysplasia developed after 24 weeks, and carcinoma in situ and squamous cell carcinoma developed after 28 weeks. H-ras mutations were detected in 13 of 25 tissue specimens (10 of 14 invasive carcinomas and 2 of 4 carcinoma in situ, 1 of 5 dysplastic tissue, and 0 of 2 normal tissues). Approximately one-half of the tumors had G to A point mutations at codon 12 of the cellular H-ras proto-oncogene on mouse chromosome 7. None had codon 11, 13, or 61 mutations. Loss of heterozygosity occurred in 5 of 14 invasive cancers. Larger invasive squamous cell carcinomas consistently lost the wild-type allele, whereas preneoplastic lesions and small tumors were heterozygous for ras. This suggests a causal relationship between carcinogen treatment, H-ras activation, and initiation of tumorigenesis. The wild-type allele in mouse chromosome 7 is lost with the progression of tumorigenesis long after exposure to the carcinogen. Thus, loss of heterozygosity of the ras gene appears to occur without multiple carcinogen-induced mutations, i.e., as a result of a cascade of events induced by an earlier ras mutation.

A 1H-NMR determination of the solution structure of the A-chain of insulin: comparison with the crystal structure and an examination of the role of solvent.

The 1H-NMR chemical shift assignments for the oxidized A-chain of bovine insulin have been determined in aqueous and 30% trifluoroethanol/water solutions. Analysis of the observed medium-range nuclear Overhauser effects indicates that in aqueous solution significant populations of the peptide exist, with a 3(10)-helical conformation over residues 12-17. This region corresponds to helix A (13-20) in the crystal structure of the 2 Zn insulin hexamer. In 30% TFE solution, the NOE data are supportive of a random coil conformation throughout the peptide.

Ligation of the iron in the heme-heme oxygenase complex: X-ray absorption, electronic absorption and magnetic circular dichroism studies.

Heme oxygenase (HO) catalyzes the first steps in the breakdown of heme to biliverdin and carbon monoxide. It is a membrane-bound protein that has been shown to exist in two isoforms, HO-1 and HO-2. Recently, a soluble, truncated form of rat HO-1 (rHO) lacking the 23 amino-acid membrane anchor has been expressed in E. coli. Extended X-ray absorption fine structure (EXAFS) data on ferric rHO and its fluoride derivative support assignment of the axial iron ligands as oxygen and/or nitrogen donors having distances similar to ferric myoglobin. The electronic absorption and magnetic circular dichroism (MCD) spectra of the ferric and ferrous protoheme complexes of rHO as well as various ligand adducts are very similar to the corresponding spectra of myoglobin. The present study is the first investigation of the heme-heme oxygenase complex with EXAFS and MCD spectroscopy and establishes that the proximal ligand to the heme in rHO is histidine. Furthermore, the close similarity between the electronic absorption and MCD spectra of ferric rHO and myoglobin over the pH range 6 to 10 is consistent with distal heme ligation of ferric rHO as a water molecule or hydroxide ion, depending on pH. Taken together and in conjunction with the results of earlier studies, EXAFS, electronic absorption, and MCD spectroscopy solidly establish that the ligands to the heme in rHO are identical to those in myoglobin, namely, histidine/H2O at low pH and histidine/OH at high pH.

Strong association of HLA-DR3/DRw9 heterozygosity with early-onset insulin-dependent diabetes mellitus in Chinese.

Studies of Caucasian and Japanese patients with insulin-dependent diabetes mellitus (IDDM) have shown that heterozygosity for certain HLA-DR antigens confers a high risk of developing the disease. The HLA antigens of 75 Chinese patients and 100 Chinese controls in Hong Kong were studied to investigate the role of HLA-DR heterozygosity in Chinese individuals. Some of the patients and controls were also tested for allotypic variation in the complement components C2, C4, and BF. Three alleles, Aw33, B17, and DR3, had increased frequencies in patients compared with controls and frequently occurred together in the same phenotype, which suggested their existence as a haplotype. There were no statistically significant differences in complement allotype frequencies between patients and controls, although the C4B null allele seemed to be associated with Aw33, B17, and DR3. No other HLA-DR antigen appeared to be associated with IDDM. However, when the patients were separated on the basis of age at onset, the frequency of DR3/DRw9 heterozygosity was markedly increased in patients presenting in the first decade of life, but there was no increase in patients presenting at greater than 20 yr of age. DRw9 is strongly associated with autoimmune disease in Chinese, whereas DR3 is not. We suggest that the major IDDM susceptibility locus in Chinese is associated with HLA-DR3 and that patients with HLA-DR3 and HLA-DRw9 have an added predisposition to autoimmune disease and therefore develop IDDM earlier than patients without DRw9.

Susceptibility to IDDM in a Chinese population. Role of HLA class II alleles.

MHC associations with IDDM in a Chinese population were studied to investigate genetic susceptibility to the disorder. The frequency of HLA-DR3 was significantly higher in the diabetic patients (19/49 [38.7%] vs. control subjects, 11/105 [10.5%], Pc less than 1.3 x 10(-3), RR = 5.3 [CI 2.3-12.1]), whereas DR4 was not (11/49 [22.4%] vs. 28/105 [26.7%], NS). The frequency of DR3/4 heterozygosity was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 0/105 [0%], P = 1.7 x 10(-3), RR = 31.5 [CI 3.8-263.6]). The frequency of DR3/9 heterozygosity also was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 2/105 [1.9%], P = 0.03, RR = 6.2 [CI 3.0-12.7]). No significant associations were noted between DQB1 alleles and IDDM. Among DR4-positive subjects, the frequency of DQB1 allele DQB1*0302 was higher in the diabetic patients (10/11 [90.0%] vs. control subjects, 12/24 [50%], Pc less than 0.05, RR = 7.0 [CI 1.3-38.0]), and the frequency of DQB1*0401 was significantly lower in the diabetic patients (2/11 [18.2%] vs. control subjects, 16/24 [66.7%], Pc = 0.04, RR = 0.1 [CI 0.02-0.46]). No DR4 subtype was associated significantly with IDDM. The frequency of DQA1*0501, a DQA1 allele, was higher in diabetic patients (22/41 [53.7%] vs. control subjects, 20/95 [21.1%], Pc less than 3 x 10(-3), RR = 4.3 [CI 2.0-9.3]). The frequency of DQA1*0301, which has been associated consistently with IDDM in other ethnic groups, was not significantly higher in the diabetic patients in this study (27/41 [65.9%] vs. control subjects, 53/95 [55.8%], NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Autoimmune thyroid dysfunction after hematopoietic stem cell transplantation.

Autoimmune thyroid disease (AITD) may occur in patients after hematopoietic stem cell transplantation (HSCT). In all, 10 cases of AITD (seven allogeneic and three autologous HSCT) were diagnosed among 721 HSCT recipients, including two patients with sequential hyper- and hypothyroidism. The 5-year actuarial rates for AITD after allogeneic and autologous HSCT were 2.9 and 4%, respectively. Significant risk factors included HSCT for chronic myeloid leukemia, the HLA B46 and DR9 loci and the A2B46DR9 haplotype, while female donors showed trend to significance. On multivariate analysis, only female donors and HLA DR9 remained significant. For autologous HSCT, the associations with HLA B46 and DR9 were also significant. Only three donors had a family history of AITD. A review of other reported cases confirmed the predominance of female donors, although the other associations including graft-versus-host disease, familial AITD and other autoimmune phenomena might be related to reporting bias. Since the actuarial incidence of AITD from female donors with predisposing HLA alleles may be over 30%, susceptible recipients should be carefully monitored. Owing to the small number of reported cases and different HLA associations with AITD in different populations, our observations await confirmatory data from other registries.

Bacterial meningitis in the elderly.

To assess the implications of meningitis in a more mature population, we reviewed the records of patients with meningitis: 71 aged 50 years and older and 138 patients aged 15 to 49 years. Among the older population, 54 (76%) had bacterial, nine (13%) had granulomatous, and eight (11%) had aseptic meningitis. Among the cases of bacterial meningitis in the older age group, Streptococcus pneumoniae accounted for 24% (13/54) and enteric bacilli accounted for 17% (9/54). Serious complications occurred in 38 elderly patients (70%) with bacterial meningitis, and mortality occurred in 24 (44%). In the younger age group with bacterial meningitis, the complication rate and mortality were 41% (13/32) and 13% (4/32), respectively. Meningitis in the elderly is likely to be bacterial and to cause greater morbidity and mortality.

Metabolic and immunologic features of Chinese patients with atypical diabetes mellitus.

OBJECTIVE: To determine whether atypical diabetes mellitus (ADM) is present in the Chinese population in Hong Kong. RESEARCH DESIGN AND METHODS: The records of Chinese patients who attended the Diabetes Clinic at Queen Mary Hospital were reviewed. We identified 11 patients who initially presented with acute diabetic ketoacidosis but subsequently displayed clinical features more typical of type 2 diabetes. Metabolic studies and HLA typing were performed to characterize this group of Chinese patients with ADM. RESULTS: C-peptide response of the patients with ADM 1 h after a standard meal was intermediate between that of type 1 diabetic patients (matched for age and duration of diabetes) and that of nondiabetic control subjects (matched for age and BMI) (analysis of variance, P = 0.02). Insulin sensitivity measured by a short insulin tolerance test was not significantly different between patients with ADM and their matched nondiabetic control subjects. HLA typing showed that none of the patients with ADM had the DR3 allele and that the frequency of DR9 was not increased. Only one patient had significantly increased levels of antibodies to GAD and islet cell antigen 512. CONCLUSIONS: ADM, which was first described in African-Americans, is seen also in Chinese subjects. These patients have significant residual C-peptide secretory capacity and should not be misdiagnosed and treated as patients with type 1 diabetes with life-long insulin therapy.

Communications: Should mechanisms be established for sharing among clinical trial investigators experiences in handling problems in design, execution, and analysis? Methodology: the case for improved communications.

Despite their long history, the number that are in operation now, and the current level of expenditures on them, clinical trials have not been the focus of sufficient methodologic research. The paucity of metholologic explorations is further aggravated by the constraints on communications regarding methodology. Those individuals working in the area of clinical trials need to establish some professional identity with the field. Methodology in the areas of design and management of clinical trials needs to be stimulated, perhaps through special requests for applications (RFAs) and requests for proposals (RFPs). Communications could be improved by the establishments of a professional society, the development of an appropriate journal, and establishment of national training and information centers for clinical trials.