Shifts in species interactions and farming contexts mediate net effects of birds in agroecosystems.

Some birds are viewed as pests and vectors of foodborne pathogens in farmlands, yet birds also benefit growers by consuming pests. While many growers seek to prevent birds from accessing their farms, few studies have attempted to quantify the net effects of bird services and disservices, let alone how net effects shift across farm management strategies. We quantified the net effect of birds on crop production across 20 California strawberry (Fragaria × ananassa) farms that varied in local management practices and landscape context. We surveyed farms for berry damage and bird droppings (as potential sources of pathogens) and implemented a large-scale exclusion experiment to quantify the impact of birds on production. We found that birds had only a slightly negative overall impact on strawberry production, reducing economic value by 3.6%. Direct bird damage and intraguild predation contributed equally to this net effect, underscoring the importance of indirect trophic interactions that may be less apparent to growers. In simple landscapes (e.g., low proportions of surrounding seminatural habitat), birds provided pest control in the interiors of farm fields, and costs from bird damage to crops peaked at field edges. In complex landscapes (e.g., high proportions of seminatural habitat), birds were more likely to disrupt pest control by feeding as intraguild predators. Nonetheless, seminatural habitat dampened bird services and disservices, and our models predicted that removing habitat around farm fields would increase costs from bird damage to crops by up to 76%. Fecal contamination of crops was extremely rare (0.01%). However, both fecal contamination and bird damage did increase on farms with higher densities of fencing and wires, where birds often perch. Our results demonstrate that maintaining seminatural habitat around farms may enhance bird diversity and mitigate bird damage without increasing food safety risks. We also show that the net effects of birds depend on farming context and vary in complex ways in relation to locations within a farm, local farm attributes, and the surrounding landscape. This context-specific variation must be considered in order to optimize the management of wild birds in agroecosystems.

Arthropod Pests and Predators Associated With Bittersweet Nightshade, a Noncrop Host of the Potato Psyllid (Hemiptera: Triozidae).

Bittersweet nightshade (Solanum dulcamara L.) is a key noncrop host of the potato psyllid (Bactericera cockerelli Sulc), proposed to be a source of the psyllids that colonize potato (Solanum tuberosum L.) fields in the northwestern United States. Here, we describe the broader community of arthropod potato pests, and also predatory arthropods, found in bittersweet nightshade patches. Over 2 yr, we sampled arthropods in patches of this weed spanning the potato-growing region of eastern Washington State. The potato psyllid was the most abundant potato pest that we found, with reproduction of these herbivores recorded throughout much of the growing season where this was measured. Aphid, beetle, and thrips pests of potato also were collected on bittersweet nightshade. In addition to these herbivores, we found a diverse community of >40 predatory arthropod taxa. Spiders, primarily in the Families Dictynidae and Philodromidae, made up 70% of all generalist predator individuals collected. Other generalist predators included multiple species of predatory mites, bugs, and beetles. The coccinellid beetle Stethorus punctillum (Weise) was observed eating psyllid eggs, while the parasitoid wasp Tamarixia triozae (Burks) was observed parasitizing potato psyllid nymphs. Overall, our survey verified the role of bittersweet nightshade as a potato psyllid host, while suggesting that other potato pests also use these plants. At the same time, we found that bittersweet nightshade patches were associated with species-rich communities of natural enemies. Additional work is needed to directly demonstrate movement of pests, and perhaps also predators, from bittersweet nightshade to potato fields.

AMG 151 (ARRY-403), a novel glucokinase activator, decreases fasting and postprandial glycaemia in patients with type 2 diabetes.

Phase I studies have shown that AMG 151 activates glucokinase, a key enzyme in glucose homeostasis. The present randomized, placebo-controlled phase IIa study evaluated the dose-effect relationship of the glucokinase activator AMG 151 relative to placebo on fasting plasma glucose (FPG) in 236 patients (33-35 patients per arm) with type 2 diabetes treated with metformin. Patients received oral AMG 151 at 50, 100 or 200 mg twice daily, AMG 151 at 100, 200 or 400 mg once daily or matching placebo for 28 days. A significant linear dose-effect trend was observed with the twice-daily regimen (p = 0.004) for change in FPG to day 28. No trend was observed with the once-daily regimen. A higher incidence of hypoglycaemia and hypertriglyceridaemia was observed with AMG 151 administration. AMG 151 significantly reduced FPG when administered twice daily but not when administered once daily in patients with type 2 diabetes treated with metformin.

Preparative Protein Production from Inclusion Bodies and Crystallization: A Seven-Week Biochemistry Sequence.

We describe how to produce and purify proteins from E. coli inclusion bodies by adapting versatile, preparative-scale techniques to the undergraduate laboratory schedule. This seven-week sequence of experiments fits into an annual cycle of research activity in biochemistry courses. Recombinant proteins are expressed as inclusion bodies, which are collected, washed, then solubilized in urea. Stepwise dialysis to dilute urea over the course of a week produces refolded protein. Column chromatography is used to purify protein into fractions, which are then analyzed with gel electrophoresis and concentration assays. Students culminate the project by designing crystallization trials in sitting-drop trays. Student evaluation of the experience has been positive, listing 5-12 new techniques learned, which are transferrable to graduate research in academia and industry.

Size-exclusion chromatography can identify faster-associating protein complexes and evaluate design strategies.

BACKGROUND: We previously developed a set of rationally designed mutant MICA protein ligands for the NKG2D immunoreceptor in which MICA was mutated at residues that do not contact NKG2D. Some of these MICA mutants, predicted by RosettaDesign to be destabilized, bound NKG2D with affinities enhanced by more than an order of magnitude when evaluated by surface plasmon resonance (SPR). FINDINGS: Small-zone size-exclusion chromatography (SEC) detected persistent high-affinity MICA mutant-NKG2D complexes in solution as early-eluting peaks. The SEC binding assay used standard protein purification instrumentation to evaluate complex stability, qualitatively paralleled the SPR results, and successfully discriminated among complexes that differed only in on-rates. We used the SEC binding assay, along with SPR, to assess the results of a follow-up design strategy targeting the non-interfacial redesigned region. Both SEC and SPR agreed that these mutations did not enhance affinity as much as previous mutants. When the SEC binding assay was run in 1 M urea, only the highest affinity complex was detected. CONCLUSION: This SEC binding assay provides a correlation with SPR results for protein complex affinities, detecting changes in complex on-rates, and tunable to lower sensitivity with 1 M urea. The SEC binding assay is complementary to other protein design evaluation methods, can be adapted to the undergraduate research laboratory, and may provide additional structural information about changes in hydrodynamic radii from elution times. Our assay allowed us to conclude that further alteration of MICA at non-contacting residues is unlikely to further enhance NKG2D affinity.

The many faces of pheochromocytoma.

OBJECTIVE: To recognize and manage pheochromocytomas in unusual settings. METHODS: Three case reports are presented with clinical, biochemical, imaging, and operative findings. The pitfalls in diagnosis of pheochromocytomas and management are addressed. RESULTS: We begin with a 27-yr-old gravida 2, para 1 Caucasian woman with unexplained tachycardia and hypertension during a routine pre-natal visit at 30 weeks estimated gestational age. Urinary studies revealed elevated catecholamines. Magnetic resonance imaging localized a 6.6-cm right adrenal mass with features consistent with a pheochromocytoma. She was medically managed with phenoxybenzamine and propranolol until 35 weeks, after which she underwent a combined Cesarean section, and open right adrenalectomy. Another patient, a 36-yr-old African-American woman presented to a hospital in cardiac arrest, with elevated serum troponins, and underwent cardiac catheterization, which revealed normal coronary arteries. A computed tomography (CT) scan revealed a left adrenal mass and CT-guided biopsy was consistent with a pheochromocytoma, although prior studies were negative. Finally, we present a 49-yr-old Caucasian woman who had a right adrenalectomy 10 yr prior and presented to the clinic with fluctuating blood pressures, headaches, and palpitations. Further testing revealed she had a recurrent metastatic pheochromocytoma. The challenges behind treating these patients are further explored. CONCLUSION: Antenatal diagnosis of pheochromocytoma, though challenging, is associated with lower maternal and fetal morbidity and mortality. The differential diagnosis for cardiac arrest in the presence of normal coronary arteries should include a pheochromocytoma. Finally, treatment with iodinated metaiodobenzylguanidine may be a therapeutic option for those patients with metastatic pheochromocytomas.

Pymetrozine causes a nontarget pest, the Colorado potato beetle (Coleoptera: Chrysomelidae), to leave potato plants.

Pymetrozine is a selective insecticide that targets aphids. Published assessments of the effects of pymetrozine on nontarget organisms focus mainly on predatory insects, and they rarely indicate toxicity. In a laboratory bioassay, survival of Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), larvae was not affected by pymetrozine exposure. We subsequently used pymetrozine to implement low-aphid-density treatments in a field experiment that involved separate manipulations of Colorado potato beetle density. Unexpectedly, the addition of Colorado potato beetle adults and eggs did not increase the densities of Colorado potato beetle larvae in plots that were sprayed with pymetrozine (applied with water and an adjuvant). In control plots sprayed with water and adjuvant (without pymetrozine), addition of Colorado potato beetles increased densities of their larvae. Data collected on a smaller scale suggest that a behavioral mechanism underlies the population-level pattern: Colorado potato beetle larvae become more active and are less likely to remain on a host plant after exposure to pymetrozine. Thus, potato, Solanum tuberosum L., growers who use pymetrozine against aphids also might benefit in terms of Colorado potato beetle control.

Photodynamic therapy with PhotoPoint photosensitiser MV6401, indium chloride methyl pyropheophorbide, achieves selective closure of rat corneal neovascularisation and rabbit choriocapillaris.

AIM: The new photosensitiser PhotoPoint MV6401, indium chloride methyl pyropheophorbide, was assessed as a possible ocular photodynamic therapy agent in a rat model of experimentally induced corneal neovascularisation and in choriocapillaris closure in the rabbit. Optimal drug and light activation parameters were determined. METHODS: MV6401 (Miravant Pharmaceuticals, Inc, Santa Barbara, CA, USA) was activated at 664 nm using a DD3-0665 (Miravant Systems Inc) 0.5 W diode laser. Corneal neovascularisation in rats was induced using an N-heptanol technique. The evaluated drug dosages, light dosages, and post-injection activation times ranged from 0.01-0.1 micromol/kg, 5-25 J/cm(2), and 10-60 minutes, respectively. The efficacy of MV6401 on normal choriocapillaris and choroidal vessels was evaluated in rabbits with indirect ophthalmoscopy, fundus photography, fluorescein angiography, and histology. In rabbits, the evaluated drug dosages, light dosages, and post-injection activation times ranged from 0.025-0.25 micromol/kg, 3.3-20 J/cm(2), and 10 minutes, respectively. RESULTS: In the rat corneal neovascularisation model, an optimal intravenous drug dosage of 0.075 micromol/kg was activated by a 20 J/cm(2) light dose at 10 minutes after drug administration, the results of which demonstrated early evidence of efficacy in ocular neovascularisation. In rabbits, closure of the normal choriocapillaris was selectively achieved at a drug dosage of 0.15 micromol/kg using light doses from 3.3 to 20 J/cm(2). CONCLUSION: PhotoPoint MV6401 is a potent photosensitiser that demonstrates both efficacy and selectivity in experimental ocular models.

Communities of practice: combining organizational learning and strategy insights to create a bridge to the 21st century

It outlines the rationale for a competence-based view of organizations and proposes a community-of-practice approach to address a number of important business challenges: mergers and acquisitions, leveraging and stretching competence across functions and SBUs, accelerating innovation, business-unit disaggregation, and outsourcing.

Establishing a selectivity survey as part of the method development activity for an isocratic reversed-phase liquid chromatographic method.

Often high-performance liquid chromatography method development is done by choosing a single C18 column and optimizing only the mobile phase composition. In this paper, it is demonstrated how to evaluate and optimize the best combination of the different stationary phase chemistries and mobile phases for a limited method development activity. By using column and mobile phase switching, it is possible to automate most of the activity in a nine-step process. Columns are chosen to represent the range of selectivity currently available. Interestingly, although the most popular column is the C18 phase, it is not the best column for the optimized methods in the cases studied.

Radiologic characterization of adrenal masses: the role of computed tomography--derived attenuation values.

BACKGROUND: Recent studies suggest that low computed tomography (CT) attenuation values can be used to differentiate benign adrenal adenomas from non-adenomas. We examined the utility of non-enhanced CT attenuation values of

Genotyping the Prop-1 mutation in Ames dwarf mice.

The Ames dwarf mouse phenotype is based on a homozygous single gene mutation in the Prop-1 gene that markedly extends life span. Since its discovery, interest in breeding these mice as a model to study retardation of aging has increased dramatically. However, the homozygous Prop-1 mutants are infertile, which necessitates breeding heterozygotes. Heterozygotes cannot be distinguished from the wildtype, while the homozygote dwarf phenotype only becomes apparent after about 3 weeks. Hence, there is a need for a simple test to genotype individual animals at an early stage for the absence or presence of one or two copies of the Prop-1 mutant gene. Here we present a Prop-1 genotyping protocol, based on a PCR reaction followed by a PflMI digestion.

Pichia pastoris Pex14p, a phosphorylated peroxisomal membrane protein, is part of a PTS-receptor docking complex and interacts with many peroxins.

The peroxisomal protein import machinery plays a central role in the assembly of this organelle in all eukaryotes. Genes encoding components of this machinery, termed peroxins or Pex proteins, have been isolated and characterized in several yeast species and in mammals, including humans. Here we report on one of these components, Pex14p, from the methylotrophic yeast Pichia pastoris. Work in other organisms has shown that Pex14p is located on the cytoplasmic surface of the peroxisomal membrane and binds peroxisomal targeting signal (PTS) receptors carrying proteins bound for the peroxisomal matrix, results that have led to the hypothesis that Pex14p is a receptor-docking protein. P. pastoris Pex14p (PpPex14p) behaves like an integral membrane protein, with its C-terminus exposed on the cytosolic side of the peroxisomal membrane. PpPex14p complexes with many peroxins, including Pex3p (Snyder et al., 1999b), Pex5p, Pex7p, Pex13p, Pex17p, itself, and a previously unreported peroxin, Pex8p. A portion of Pex14p is phosphorylated, but both phosphorylated and unphosphorylated forms of Pex14p interact with several peroxins. The interactions between Pex14p and other peroxins provide clues regarding the function of Pex14p in peroxisomal protein import.

Import of peroxisomal matrix and membrane proteins.

This review summarizes the progress made in our understanding of peroxisome biogenesis in the last few years, during which the functional roles of many of the 23 peroxins (proteins involved in peroxisomal protein import and peroxisome biogenesis) have become clearer. Previous reviews in the field have focussed on the metabolic functions of peroxisomes, aspects of import/biogenesis the role of peroxins in human disease, and involvement of the endoplasmic reticulum in peroxisome membrane biogenesis as well as the degradation of this organelle. This review refers to some of the earlier work for the sake of introduction and continuity but deals primarily with the more recent progress. The principal areas of progress are the identification of new peroxins, definition of protein-protein interactions among peroxins leading to the recognition of complexes involved in peroxisomal protein import, insight into the biogenesis of peroxisomal membrane proteins, and, of most importance, the elucidation of the role of many conserved peroxins in human disease. Given the rapid progress in the field, this review also highlights some of the unanswered questions that remain to be tackled.

Distinct spectra of somatic mutations accumulated with age in mouse heart and small intestine.

Somatic mutation accumulation has been implicated as a major cause of cancer and aging. By using a transgenic mouse model with a chromosomally integrated lacZ reporter gene, mutational spectra were characterized at young and old age in two organs greatly differing in proliferative activity, i.e., the heart and small intestine. At young age the spectra were nearly identical, mainly consisting of G. C to A.T transitions and 1-bp deletions. At old age, however, distinct patterns of mutations had developed. In small intestine, only point mutations were found to accumulate, including G.C to T.A, G.C to C.G, and A.T to C.G transversions and G.C to A.T transitions. In contrast, in heart about half of the accumulated mutations appeared to be large genome rearrangements, involving up to 34 centimorgans of chromosomal DNA. Virtually all other mutations accumulating in the heart appeared to be G.C to A.T transitions at CpG sites. These results suggest that distinct mechanisms lead to organ-specific genome deterioration and dysfunction at old age.

The peroxin Pex19p interacts with multiple, integral membrane proteins at the peroxisomal membrane.

Pex19p is a protein required for the early stages of peroxisome biogenesis, but its precise function and site of action are unknown. We tested the interaction between Pex19p and all known Pichia pastoris Pex proteins by the yeast two-hybrid assay. Pex19p interacted with six of seven known integral peroxisomal membrane proteins (iPMPs), and these interactions were confirmed by coimmunoprecipitation. The interactions were not reduced upon inhibition of new protein synthesis, suggesting that they occur with preexisting, and not newly synthesized, pools of iPMPs. By mapping the domains in six iPMPs that interact with Pex19p and the iPMP sequences responsible for targeting to the peroxisome membrane (mPTSs), we found the majority of these sites do not overlap. Coimmunoprecipitation of Pex19p from fractions that contain peroxisomes or cytosol revealed that the interactions between predominantly cytosolic Pex19p and the iPMPs occur in the organelle pellet that contains peroxisomes. These data, taken together, suggest that Pex19p may have a chaperone-like role at the peroxisome membrane and that it is not the receptor for targeting of iPMPs to the peroxisome.

Time-resolved fluorescence spectra of arterial fluorescent compounds: reconstruction with the Laguerre expansion technique.

The time-resolved fluorescence spectra of the main arterial fluorescent compounds were retrieved using a new algorithm based on the Laguerre expansion of kernels technique. Samples of elastin, collagen and cholesterol were excited with a pulsed nitrogen laser and the emission was measured at 29 discrete wavelengths between 370 and 510 nm. The expansion of the fluorescence impulse response function on the Laguerre basis of functions was optimized to reproduce the observed fluorescence emission. Collagen lifetime (5.3 ns at 390 nm) was substantially larger than that of elastin (2.3 ns) and cholesterol (1.3 ns). Two decay components were identified in the emission decay of the compounds. For collagen, the decay components were markedly wavelength dependent and hydration dependent such that the emission decay became shorter at higher emission wavelengths and with hydration. The decay characteristics of elastin and cholesterol were relatively unchanged with wavelength and with hydration. The observed variations in the time-resolved spectra of elastin, collagen and cholesterol were consistent with the existence of several fluorophores with different emission characteristics. Because the compounds are present in different proportions in healthy and atherosclerotic arterial walls, characteristic differences in their time-resolved emission spectra could be exploited to assess optically the severity of atherosclerotic lesions.

Presentation and patterns of late recurrence of olfactory groove meningiomas.

The objective of this article is to present the recurrence pattern of olfactory groove meningiomas after surgical resection. Four patients, one female and three males, with surgically resected olfactory groove meningiomas presented with tumor recurrence. All patients underwent resection of an olfactory groove meningioma and later presented with recurrent tumors. The mean age at initial diagnosis was 47 years. All presented initially with vision changes, anosmia, memory dysfunction, and personality changes. Three patients had a preoperative MRI scan. All patients had a craniotomy, with gross total resection achieved in three, and 90% tumor removal achieved in the fourth. Involved dura was coagulated, but not resected, in all cases. Three patients were followed with routine head CT scans postoperatively, and none was followed with MRI scan. The mean time to recurrence was 6 years. Three patients presented with recurrent visual deterioration, and one presented with symptoms of nasal obstruction. Postoperative CT scans failed to document early tumor recurrence, whereas MRI documented tumor recurrence in all patients. Tumor resection and optic nerve decompression improved vision in two patients and stabilized vision in two. Complete resection was not possible because of extensive bony involvement around the anterior clinoid and inferior to the anterior cranial fossa in all cases. Evaluation of four patients with recurrent growth of olfactory groove meningiomas showed the epicenter of recurrence to be inferior to the anterior cranial fossa, with posterior extension involving the optic canals, leading to visual deterioration. This location led to a delay in diagnosis in patients who were followed only with routine CT scans. Initial surgical procedures should include removal of involved dura and bone, and follow-up evaluation should include formal ophthalmologic evaluations and routine head MRI scans.