Sensitivity of Meloidogyne incognita and Rotylenchulus reniformis to Fluopyram.

Fluopyram is a succinate dehydrogenase inhibitor (SDHI) fungicide that is being evaluated as a seed treatment and in-furrow spray at planting on row crops for management of fungal diseases and its effect on plant-parasitic nematodes. Currently, there are no data on nematode toxicity, nematode recovery, or effects on nematode infection for Meloidogyne incognita or Rotylenchulus reniformis after exposure to low concentrations of fluopyram. Nematode toxicity and recovery experiments were conducted in aqueous solutions of fluopyram, while root infection assays were conducted on tomato. Nematode paralysis was observed after 2 hr of exposure at 1.0 µg/ml fluopyram for both nematode species. Using an assay of nematode motility, 2-hr EC50 values of 5.18 and 12.99 µg/ml fluopyram were calculated for M. incognita and R. reniformis, respectively. Nematode recovery in motility was greater than 50% for M. incognita and R. reniformis 24 hr after nematodes were rinsed and removed from a 1-hr treatment of 5.18 and 12.99 µg/ml fluopyram, respectively. Nematode infection of tomato roots was reduced and inversely proportional to 1-hr treatments with water solutions of fluopyram at low concentrations, which ranged from 1.3 to 5.2 µg/ml for M. incognita and 3.3 to 13.0 µg/ml for R. reniformis. Though fluopyram is nematistatic, low concentrations of the fungicide were effective at reducing the ability of both nematode species to infect tomato roots.

First Report of Sclerotinia Blight of Peanut Caused by Sclerotinia minor in Arkansas.

In September, 2013, symptoms similar to Sclerotinia blight caused by Sclerotinia minor were observed on Runner peanut (cv. FloRun 107) in a commercial field near Pocahontas, Arkansas, in Randolph County (2). Blighted plants with wilted leaves were observed in several small (30 × 30 cm) clustered foci located near the end of a 20-ha, furrow-irrigated field. Peanut stems within the lower canopy of symptomatic plants had straw-colored lesions, with white fluffy mycelium and small (<2.0 mm diam.), black, irregularly shaped sclerotia. Stems on plants with severe symptoms were shredded in appearance, with small black sclerotia inside the stem tissue (2). Final disease incidence near harvest in mid-October was less than 1% of the field. Sclerotinia blight symptoms were also observed in 2013 on Runner (cvs. FloRun 107, Georgia 09B, and Florida 07) and Spanish peanut (cvs. OLin and OL06) research plots near Newport, AR, in Jackson County. Disease incidence among cultivars in these research plots was <1% for all cultivars except FloRun 107, which had a disease incidence of 2.6% for a 849.8 m2 plot. Isolations from surface-disinfected leaves on potato dextrose agar (PDA) consistently yielded white, fluffy mycelia with small (0.5 to 2.0 mm diam.), black, irregularly shaped sclerotia typical of S. minor (2). Six-week-old peanut plants (cv. FloRun 107) growing in pots were used to test pathogenicity. Each plant was inoculated by placing an agar plug (5 mm diam.), collected from the edge of an actively growing S. minor culture, on the main peanut stem. Plants (n = 5) were incubated for 8 days in a humidity chamber where temperatures ranged from 24 to 30°C and relative humidity remained >95%. Characteristic symptoms of Sclerotia blight were observed on all inoculated peanut plants whereas none of the plants (n = 3) inoculated with sterile PDA agar plugs expressed symptoms. Pathogenicity tests were repeated on peanut cvs. Flavor Runner 458 and Georgia 09B with similar results. S. minor was consistently isolated from symptomatic tissue on PDA, fulfilling Koch's postulates. To our knowledge, this is the first report of S. minor on peanut or any host in Arkansas or the Mid-South region. The two peanut fields with Sclerotinia blight had a history of soybean production, and S. minor may have gone undetected on soybean or one of many host weed species (1). Since S. minor is a major economic pathogen of peanut, commonly causing yield losses of 10% (2), it will likely be a significant factor in Arkansas and Mid-South peanut production. References: (1) M. S. Melzer et al. Can. J. Plant Pathol. 19:272, 1997. (2) D. M. Porter and H. A. Melouk. Sclerotinia blight. Page 34 in: Compendium of Peanut Diseases, 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathological Society, St. Paul, MN, 1997.

Effects of a weak oestrogenic active chemical (4-tert-pentylphenol) on pair-breeding and F1 development in the fathead minnow (Pimephales promelas).

A fish full life-cycle (FFLC) is the most comprehensive test to determine reproductive toxicity of chemicals to fish and this is likely to apply equally to endocrine active chemicals (EACs). However, FFLC tests use large numbers of animals, are expensive and time consuming. Alternative chronic tests, to the FFLC, potentially include sensitive life-stage windows of effect, such as sexual differentiation, early gonadal development and reproduction. In this paper, a fish pair-breeding study was applied to assess the biological effects of a weak environmental oestrogen, 4-tert-pentylphenol (4TPP), on reproduction and subsequent development of the F1 generation. The results of this study were then compared with the results for a published FFLC study, with this chemical. Fathead minnows (Pimephales promelas) were held in pairs and their reproductive performance assessed over two concurrent 21-day periods, the first without exposure to the test chemical, followed by the second with exposure to the test chemical, in a flow-through system at 25+/-1 degrees C. Embryos from two pairs, per treatment, were subsequently grown up in clean water until 90 days post-hatch to assess developmental effects of the parental exposure on the F1 generation. Nominal (measured geometric mean, time weighted) test concentrations of 4TPP were 56 (48), 180 (173) and 560 (570) microg l(-1). A significant decrease in fecundity was observed in all 4TPP exposed fish (mean number of eggs spawned per pair and number of spawns per pair) when compared to the solvent control. Vitellogenin (VTG) was significantly elevated in F0 males exposed to 560 microg 4TPPl(-1). Somatic endpoints, secondary sexual characteristics (SSC) and gonadosomatic index (GSI) were not affected by the 4TPP exposure. In the F1 generation, there were no treatment-related effects on hatching success, survival, growth, SSC or GSI. Histological examination of the gonads of the F1 fish revealed no treatment-related effects on sex ratio, sexual differentiation or sexual development. However, plasma VTG concentrations were significantly elevated in F1 male fish, derived from parents that had previously been exposed to 4TPP at concentrations of > or = 180 microg l(-1). These data show that the reproductive performance test is suitable for detecting weak environmental oestrogenic chemicals and that exposure of adult fish to oestrogens can result in altered biomarker expression (VTG) of the F1 generation. Our findings indicate that the reproductive performance test was as sensitive for detecting effects on reproduction when compared with a published FFLC test for 4TPP.

Development of chronic tests for endocrine active chemicals. Part 1. An extended fish early-life stage test for oestrogenic active chemicals in the fathead minnow (Pimephales promelas).

An extended early-life stage test (based on OECD test guideline 210) was developed to allow the evaluation of a weak environmental oestrogen, 4-tert-pentyphenol (4TPP), on sexual differentiation and gonadal development. Fathead minnow (Pimephales promelas) embryos were exposed to three concentrations of 4TPP (56, 180 and 560 microg l(-1)) in a flow-through system, at 25+/-1 degrees C, for <107 days post-hatch (dph). In addition, some embryos were exposed to 180 microg 4TPPl(-1) until 30 or 60 dph, after which they were exposed to dilution water only until 107 dph. At 30, 60 and 107 dph fish were evaluated for growth and gonadal development (via histology), and at 107 dph fish were also evaluated for secondary sexual characteristics (SSC), gonadosomatic index (GSI) and plasma vitellogenin (VTG). There were no effects of 4TPP on hatching success or survival, however, there was a delay in the time taken for embryos to hatch (560 microg 4TPPl(-1)). No treatment-related effects were observed on fish growth, with the exception of at 107 dph when the condition factor in female fish was reduced in all 4TPP continuous exposure treatments. Plasma VTG was only elevated in female fish exposed to 180 microg 4TPPl(-1) and inhibition of gonadal growth (GSI) occurred only in females exposed to 560 microg 4TPPl(-1). Histological examination of the gonads revealed delays and disruption in male sexual differentiation and development (180 microg 4TPPl(-1)) and no testicular tissue was observed in any fish exposed to 560 microg 4TPPl(-1). Mixed gonads (predominately testes with a scattering of primary oocytes) were present in fish exposed to all doses of 180 microg 4TPPl(-1) at 107 dph. Feminisation of the reproductive ducts (formation of an ovarian like cavity) occurred in the testis of all males exposed to 180 microg l(-1), regardless of length of 4TPP exposure. Results indicate that the period of 30-60 dph appears to be the sensitive window for disruption of formation of the reproductive duct and this effect is not reversible when the fish are transferred to dilution water. The data also show that this integrative test is suitable for the detection of a weak environmental oestrogen and comparisons of these results with that of a fish full life-cycle, in medaka, indicate that this test could be a suitable surrogate for a fish full life-cycle.

Successful detection of (anti-)androgenic and aromatase inhibitors in pre-spawning adult fathead minnows (Pimephales promelas) using easily measured endpoints of sexual development.

Screening assays have been successfully developed for the detection of (anti-)oestrogenic substances in several fish species, including the fathead minnow (Pimephales promelas). Previous work suggested that pre-spawning adult fathead minnows might be an appropriate life-stage for developing a screen to detect endocrine active substances (EASs). Pre-spawning adult fathead minnows, in which their phenotypic sex could be determined, were exposed in flow-through systems to three reference substances for 21 days, at 25 degrees C. Male and female fish, held in separate tanks, were exposed to dihydrotestosterone (DHT, androgen), flutamide (anti-androgen) and fadrozole (aromatase inhibitor). Nominal (mean measured) concentrations for DHT were 10 (6.0), 32 (6.1) and 100 (8.6) microg l(-1), for flutamide, 100 (95.3), 320 (320.4) and 1000 (938.6) microg l(-1) and for fadrozole, 25 (24.8), 50 (51.7) and 100 (95.5) microg l(-1). After 14 and 21 days exposure, fish were evaluated for growth, secondary sexual characteristics (SSCs, number and prominence of nuptial tubercles), gonadosomatic index (GSI) and plasma vitellogenin (VTG) concentrations. Development of nuptial tubercles was sensitive to both DHT and flutamide exposure. Exposure to DHT significantly increased the number of nuptial tubercles (male characteristic) in both males (more abundant) and females, after 14 days. Flutamide (938.6 microg l(-1), day 21) significantly reduced nuptial tubercle number in male fish. Fadrozole significantly inhibited ovarian growth (lower GSI) and significantly induced testis growth (51.7 and 95.5 microg l(-1)), after 21 days. Plasma VTG concentrations were significantly elevated in male fish (6.1 and 8.6 microg l(-1)), but inhibited in female fish (6.0 microg l(-1)), exposed to DHT. Flutamide had no effect on plasma VTG in male fish, but significantly induced VTG in female fish, after 21 days. Fadrozole significantly inhibited VTG in females and induced VTG synthesis in males, at day 21. These results show that SSCs, GSI and plasma VTG concentrations can be used in pre-spawning adult fathead minnows to screen for a range of classes of EASs. This work complements other published studies in supporting the current OECD effort towards validating a 21 days non-spawning fish screening assay for assessing (anti-)oestrogens, aromatase inhibitors and (anti-)androgens.

Reproductive effects of long-term exposure to Bisphenol A in the fathead minnow (Pimephales promelas).

Bisphenol A (BPA), a high-volume chemical used to make polycarbonate plastic, epoxy resins, and other chemicals has been reported to be weakly estrogenic. To investigate the effects of long-term exposure to Bisphenol A, a multigeneration study was conducted in which fathead minnows (Pimephales promelas) were exposed to water concentrations of BPA in the range from 1 to 1280 micrograms/L. In this paper, we report the growth and reproductive effects of BPA on sexually mature adults in the F0 generation (after 43, 71, and 164 d of exposure) and the effects on hatchability in the F1 generation. Mean measured concentrations of BPA in the water for all doses, over a 164-d exposure period, were between 70% and 96% of nominal. An inhibitory effect of BPA on somatic growth (length and weight) occurred in adult male fish exposed to 640 and 1280 micrograms/L (after 71 and 164 d). BPA induced vitellogenin synthesis (VTG; a biomarker for estrogen exposure) in males at concentrations of 640 and 1280 micrograms/L after 43 d and 160 micrograms/L after 71 d. In females, plasma VTG concentrations were elevated above controls only after 164-d exposure to 640 micrograms/L. Inhibition of gonadal growth (as measured by the gonadosomatic index) occurred in both males and females at concentrations of 640 and 1280 micrograms/L after 164 d. In males, a concentration of 16 micrograms/L altered the proportion of sex cell types in the testis, suggesting inhibition of spermatogenesis. Concentrations of BPA that induced VTG synthesis and affected gonadal development were lower than those that resulted in discernible effects on reproductive output. Egg production was inhibited at a BPA concentration of 1280 micrograms/L, and hatchability in the F1 generation was reduced at a BPA concentration of 640 micrograms/L (there were not enough eggs spawned in the 1280 micrograms/L group for hatchability studies to be conducted). The results demonstrate that BPA acts as a weak estrogen to fish when administered via the water, with effects on breeding at and above 640 micrograms/L.

Resistance properties of Thera-Band tubing during shoulder abduction exercise.

STUDY DESIGN: Single-group, repeated measures. OBJECTIVES: To investigate the relationship between tubing length and tubing tension for 6 colors of Thera-Band tubing (each color representing a different level of resistance) and to estimate the resistive shoulder torque provided during shoulder abduction exercise. BACKGROUND: Thera-Band tubing is popular for providing resistance in rehabilitation strengthening programs. Unfortunately, it is difficult to compare use of elastic tubing with other resistance training methods because no published data exist on how much resistance is being provided during exercise. METHODS AND MEASURES: Nine male and 6 female subjects (age, 25.9 +/- 3.6 years; height, 173 +/- 10 cm) performed shoulder abduction, using 6 colors of tubing. A strain gauge attached at the fixed end of the tubing directly measured the tension generated during stretch. For each color of tubing, each subject momentarily held a position at 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees of abduction. Shoulder joint abduction, limb segment position, and tubing length were analyzed by means of the Peak Motion Measurement System. Simple linear regression equations predicted tubing tension from percent change in tubing length at the joint angle positions. A 2-way (5 x 6) repeated-measures ANOVA determined the mean differences in tubing tension across tubing colors at the shoulder abduction positions. RESULTS: Strong linear relationships were found for each tubing tension when referenced according to changes in tubing length. Significant differences in tension were found for the various colors of tubing. The resistive torque curves for each color tubing were similar to isotonic exercise. CONCLUSIONS: Thera-Band tubing provides linear resistance during shoulder abduction, but the resistive torque provided by the tubing mimics isotonic exercise.

Effects of moderate hyperglycemia on the temporal profile of brain tissue intracellular pH and [Mg2+] after global cerebral ischemia in rats.

In an attempt to understand the mechanisms by which preischemic plasma glucose (pg) worsens neurologic and neuropathologic outcomes, we investigated the effect of moderate preischemic hyperglycemia (200 mg/dl < mean plasma glucose < 360 mg/dl) on postischemic energy metabolism, tissue intracellular pH (pHi) and tissue free intracellular pMg (= -log[Mg2+]) over a one week period after transient global cerebral ischemia in the rat. In vivo 31P nuclear magnetic resonance spectroscopy was performed prior to and daily up to 1 week (wk) in rats after 12 min of forebrain ischemia, induced by bicarotid occlusion concurrent with systemic hypotension. Preischemic plasma glucose significantly affected 1 wk postischemic survival (p = 0.05, Fisher's exact test). The temporal profile of the brain tissue pHi was significantly different (p < 0.03) between the moderate hyperglycemic (H-1wk, n = 7, mean pg = 266.0 +/- 47.3 mg/dl) and the normoglycemic (N-1wk, n = 8, mean pg = 91.2 +/- 23.7 mg/dl) ischemic animals over 1 wk. Postischemic tissue alkalosis was measured at 24 (p = < 0.006) and 48h (p = 0.001) postischemia in the N-1wk group. A single marginally significant (p = 0.011) mean pHi upshift was measured at 72h postischemia in the H-1wk group. The mean change in pHi at 24h postischemia from the baseline values in moderate hyperglycemic animals that survived only 48h after ischemia (H-48h, n = 6, mean pg = 298.8 +/- 70.1 mg/dl) was significantly lower (p = 0.02) than that of the N-1wk ischemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study for the enumeration of peripheral blood white cell counts below 2.0 x 10(9)/1 using counting chambers and the Coulter Counter model "S".

Low white cell counts are performed in many laboratories by a visual method as the method of choice. In this study, the visual count has been compared to that obtained by the Coulter Model "S". The results obtained by the two methods show very close correlation, thus allowing the Coulter Model "S" to be used with confidence for all low white cell counts provided certain precautions are taken.