A three-year study of viable airborne fungi in the North Carolina Zoological Park R.J.R. Nabisco Rocky Coast Alcid Exhibit.

Aspergillosis is a common cause of mortality in captive birds, particularly in recently imported birds or captive chicks and their parents. Use of the Andersen N-6 single-stage viable air sampler in the North Carolina Zoological Park (NCZP) R.J.R. Nabisco Rocky Coast Alcid Exhibit before and after the introduction of birds allowed a unique study of the mycological content of the air in a developing self-contained ecosystem. The Alcid Exhibit had a median count of 17 colony-forming-units (CFU)/m3 of air in comparison to 200-500 CFU/m3 and 1,000-3,500 CFU/m3 reported in human dwellings and the NCZP R.J. Reynolds Forest Aviary, respectively. Cladosporium and Penicillium represented 21.3% and Aspergillus 1.08% of the fungi collected. During the study, no respiratory mycoses were reported in any of the alcids. Continuous high-efficiency particulate air filtration, maintenance of low exhibit air temperatures, and an environment with little residual organic material capable of supporting fungal growth were important factors contributing to low colony counts. All colony counts >100 CFU/m3 in the exhibit were related to the apparent introduction of fungi from outside the facility. A reduction in the number of fungi transported from an external source into enclosed cool-temperature aviaries may be sufficient to avoid outbreaks of aspergillosis.     

Chemical interactions with the herbicide propanil on propanil-resistant barnyardgrass

We are examining the interaction of compounds with the herbicide propanil to find synergistic or additive actions that can increase efficacy against propanil-resistant barnyardgrass [Echinochloa crus-galli] (R-BYG) without substantial injury to rice. Field tests (herbicidal injury) and laboratory tests (chlorophyll quantification in excised leaves; measurement of chlorophyll fluorescence to determine PSII inhibition) have been conducted on R-BYG and rice tissue exposed to various rates of propanil and additive. Important synergistic interactions on R-BYG in laboratory and field tests were found with propanil plus either the herbicides anilophos or piperophos, or the insecticide carbaryl. In laboratory tests, the insecticide methiocarb and PPG-124 (p-chlorophenyl N-methylcarbamate) were highly effective synergists with propanil on R-BYG. Other important interactions occurred with certain concentrations/application rates when propanil was combined with the herbicides quinclorac, thiobencarb, molinate, or pendimethalin (field tests). Combinations of these or other chemicals with propanil may provide additive or synergistic action useful to control R-BYG without increasing rice injury. Such mixtures might also prevent or delay the development of propanil resistance in this weed species.     

Chemical stress can increase crop yield

Low dose chemical stress has been shown to increase plant vegetative growth, though not all chemicals induce the response. Glyphosate is the most widely used herbicide by volume and treated area. At low doses, it can increase growth in a variety of species. Here we show that a glyphosate-induced growth increase can be transformed into an increase in crop yield, if applied at the right time. Glyphosate, in the dose range of 2.5–20 g a.e. ha⁻¹, corresponding to less than 1% of the rate normally used for weed control in the field, increased grain yield of barley by 12–15% when applied at the time of grain filling. Straw yield and the quality of the grains in terms of nitrogen and starch content were not affected by the treatment. The physiological mechanism behind this counter intuitive increase in growth is still unknown, as are possible adverse effects. It is, however, evident that understanding the physiological processes behind chemically induced growth increases in plants holds the promise of improving food yield.     

Pedigree Reconstruction with Genome-Wide Markers in Potato

Reliable pedigree information facilitates a scientific approach to breeding, but errors can be introduced in many stages of a breeding program. Our objective was to use single nucleotide polymorphisms (SNPs) to check the pedigree records of elite North American potato germplasm. A population of 719 tetraploids was genotyped with an Infinium SNP array, yielding 5063 high-quality markers. Based on pedigree records, the dataset contained 198 parent-offspring trios, of which 182 were consistent with the marker data. For 13 of the 16 trios with a pedigree error, the true parent was identified in the population. By comparing the additive relationship matrix calculated from pedigree with the genetic distance calculated from markers, an additional 24 pedigree modifications were proposed, including the paternity of several varieties developed with bulk pollen. To ensure accurate pedigree records are published in the future, we recommend that new varieties be SNP genotyped and checked against this dataset.     

Lower lethal temperature of the endangered Rio Grande silvery minnow and its implications for propagation and reintroduction

The lower lethal temperature of the endangered Rio Grande silvery minnow, Hybognathus amarus, was estimated from survival rates of fish overwintered in above-ground tanks. Temperature went to 0.0°C both winters. In 2012–2013, survival of Age class 0 fish was 79.87%, and in 2013–2014, survival of Age class 1 fish was 97.1%, suggesting that if Rio Grande silvery minnow is subjected to seasonal temperature changes, lower lethal temperature is ≤0.0°C. Results show that heating hatchery water in the winter is unnecessary. Additionally, current management guidelines that preclude reintroduction of the species into river sections where winter temperatures are ≤1°C must be reevaluated.     

Effect of bursal antisteroidogenic peptide (BASP) on chicken embryonic pituitary secretion of growth hormone (GH) and prolactin (PRL): evaluation in a reverse hemolytic plaque assay (RHPA)

Using the reverse hemolytic plaque assay described in the present investigation, a secretagogue activity of bursal antisteroidogenic peptide (BASP) for growth hormone (GH) or prolactin (PRL) secretion was observed in chicken Day 20e pituitary cell monolayers. Partially purified BASP (ppBASP), at all concentrations evaluated (0.25 BEQ/ml, 0.75 BEQ/ml, or 1.5 BEQ/ml), induced PRL secretion by isolated lactotrophs above (P < 0.05) basal levels during the 2- and 6-hr incubation. At the 18-hr time point, neither ppBASP nor vasoactive intestinal polypeptide (VIP) was efficacious (P < 0.05) in causing an elevation in PRL-secreting cells above basal levels. ppBASP, at all concentrations evaluated (0.25 BEQ/ml, 0.75 BEQ/ml, or 1.5 BEQ/ml), caused an increase in the percentage of GH-secreting cells above (P < 0.05) basal levels during the 18-hr incubation. When evaluating the 2-hr time point alone, ppBASP, at 0.75 or 1.5 BEQ/ml, significantly (P < 0.05) elevated the percentage of GH-secreting cells to above basal levels. After the 6-hr incubation, ppBASP at 0.25 or 0.75 BEQ/ml, was efficacious in causing elevated (P < 0.05) GH secretion above basal levels. The present study indicates a secretagogue activity of BASP on PRL or GH secretion by chicken embryonic anterior pituitary cells in vitro.     

Characterization of glyphosate resistance in cloned Amaranthus palmeri plants

Glyphosate‐resistant Palmer amaranth from Georgia (GA), USA, possesses multiple copies of the gene that encodes 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS), the enzyme target site of this herbicide. The cloned plants of glyphosate‐resistant and glyphosate‐susceptible Palmer amaranth biotypes from Mississippi (MS), USA, and GA were evaluated for glyphosate injury (digital imaging) in leaf disc bioassays. Four groups (three resistant groups: two from MS [G and R] and one from GA [C7]; one susceptible group from GA [C3]) were chosen for cloning to facilitate long‐term studies. After exposure to glyphosate (1.0 mmol L^–1, 144 h), the level of injury (mean value) was low in the resistant groups, while a higher level of injury was found in the susceptible group. However, the individual injury values within all groups varied widely. The mean EPSPS gene copy number of these groups was G ≥ R > C7 >>> C3. However, a higher copy number did not always convey increased resistance in these bioassays. When the copy number was high (>20), 81.5% of the bioassayed plants exhibited little or no injury and only ～20% were significantly injured, while 50% of the plants with a low copy number (<20) remained healthy. Overall, no strong statistical correlation of the copy number versus injury occurred in these cloned plants and no statistical relationship of resistance and copy number with the sex of the MS plants was observed. The results suggest that although an elevated copy number of the EPSPS gene can instill resistance, other mechanisms might contribute to the overall glyphosate resistance of Palmer amaranth in these plants.     

ANTICIPATING THE GROWTH OF AN OCEAN AQUACULTURE INDUSTRY

In assessing the future expansion of aquaculture in coastal-ocean environments, most studies focus only on the constraint posed by the local environmental assimilative capacity. In open-ocean environments, however, the assimilative capacity is difficult to gauge. We develop an alternative economic approach for projecting the growth of the open-ocean aquaculture industry. We evaluate equilibria in the market for seafood, where the product may be supplied either by a wild-harvest fishery or open-ocean aquaculture or both. In our framework, the net demand for farmed fish determines the size of the aquaculture industry and, in turn, the levels of pollution discharges. We illustrate our approach with a case study of a groundfish fishery and the proposed open-ocean aquaculture of Atlantic cod in New England. We find that, for a range of competitive production costs for aquaculture, the optimal industry structure would comprise both a wild-harvest fishery and aquaculture.