Evaluation of wheat (Triticum aestivum L.) phenolic acids during grain development and their contribution to Fusarium resistance.

The phenolic acid profiles of six cultivars of wheat with known tolerance to Fusarium head blight were evaluated during plant development from anthesis through maturity. Analysis by HPLC of grain at anthesis revealed that p-coumaric and ferulic acid were the two principal phenolic compounds present. The effect of these two phenolic acids on Fusarium species was evaluated in vitro. Both phenolic acids demonstrated significant reductions (p < 0.05) of Fusarium species growth at all concentrations tested. Ferulic acid is the primary phenolic acid in grain at all stages of development, and its concentration increased steadily during grain development prior to a 50% decrease during grain ripening. The accumulation of ferulic acid synthesis from anthesis until approximately 20 days after anthesis appears related with cultivar resistance to Fusarium. Concentrations of ferulic acid in the grain were similar at maturity, implying that the end-use quality would be similar for both resistant and susceptible cultivars.

Agronomic performance of lines derived from anther culture, maize pollination and single-seed descent in a spring wheat cross.

Anther culture and maize hybridization are two frequently used techniques for doubled haploid production in wheat (Triticum aestivum L.). Information on the field performance of lines derived from these techniques is limited. This study was conducted to compare the performance of F(4:6) lines obtained by single-seed descent with lines obtained by anther culture and maize (Zea mays L.) pollination from the same cross of spring wheat, 'Chris'/MN 7529. Thirty-three lines derived from each of those techniques were evaluated in six environments for grain yield, protein content, test weight, heading date, kernel weight and plant height. Mean performance of the single-seed descent lines exceeded performance of the anther culture lines for grain yield, kernel weight and plant height with no apparent differences for grain protein content, test weight and heading date. No differences between trait means for the single-seed descent and maize pollination lines were found except for plant height. The best 5 lines from each method for grain yield, protein content and test weight were similar in performance except that the protein content was higher for the maize pollination lines than for the single-seed descent lines. Acceptable levels of agronomic performance could be found among lines from each method. Wide acceptance of the doubled haploid technique for pure line production in breeding programs may, however, be limited by the often poor efficiency of doubled haploid line production, resulting in smaller population sizes for selection of desirable traits in comparison to the single-seed descent method.

Repeatability and Relationship of Incidence and Severity Measures of Scab of Wheat Caused by Fusarium graminearum in Inoculated Nurseries.

Breeders of hard red spring wheat (Triticum aestivum) are attempting to incorporate resistance to scab, caused by Fusarium graminearum. In artificially inoculated, replicated field plots, 37 wheat entries (inbred lines or cultivars) were evaluated for 3 years and an additional 60 entries for 2 of the 3 years for incidence (percent spikes infected), severity (percent infected spikelets within infected spikes), and disease index (percent infected spikelets in 50-spike sample). From year to year, entries had similar index values, with coefficients of determination (r 2) ranging from 0.59 to 0.78, with a mean of 0.73. Entries appeared slightly more similar from year to year for incidence than for severity, although both measures of disease had highly significant r 2 values. Incidence and severity were highly correlated in the wheat germ plasm examined; r 2 values in single years ranged from 0.51 to 0.67, with a mean of 0.64. A representative subset of 22 entries was included for a fourth year. None of the measures of disease in year 4 correlated with their counterparts in any of the first 3 years. This loss of repeatability may have been caused by severe lodging or by high temperatures during the evaluation period that accelerated disease progress and wheat maturity during year 4. Incidence and severity remained correlated in year 4 (r 2 = 0.60).

Effects of sulfur dioxide or ammonium sulfate exposure, alone or combined, for 4 or 8 months on normal and elastase-impaired rats.

Normal and lung-impaired rats were compared after exposure to SO2 and/or (NH4)2SO4 for 4 or 8 months, or for 8 months plus 3 months recovery. Young adult male Sprague-Dawley rats were pretreated intratracheally with either physiologic saline (normal lungs) or porcine pancreatic elastase (impaired lungs). Rats from each pretreatment group were exposed to filtered air (control), to SO2 (1 ppm) or (NH4)2SO4 (0.5 mg/m3), or to combined SO2 + (NH4)2SO4 for 5 hr/day, 5 days/week. Morphologic, physiologic, and immunologic criteria were evaluated. At 4 months cellular immunologic responsiveness was not impaired, but physiologic changes were detected. Morphologic changes were apparent in all time periods. Elastase-induced changes included greater lung volumes, emphysema, and alveolar interstitial fibrosis. Pollutant effects included bronchiolar epithelial hyperplasia and changes in alveolar mean chord length (MCL). Relative to controls, bronchiolar epithelial hyperplasia and MCL increased in saline/pollutant groups, but decreased in elastase/pollutant rats at 4 months. The pretreatment/pollutant interaction was not observed at 8 months. Elastase effects persisted throughout the recovery period. Pollutant effects were more transitory, although alveolar septal fibrosis was greater in saline/(NH4)2SO4 rats at 8 months. Pulmonary function changes associated with elastase included increases in residual volume, functional residual capacity, and the residual volume/total lung capacity ratios. The alveolar plateau of single-breath washout (N2 slope) was significantly steeper in elastase-treated rats but less steep in animals exposed to SO2 or to (NH4)2SO4 than in those exposed to air only.

Effects of ammonium nitrate aerosol exposure on lung structure of normal and elastase-impaired rats and guinea pigs.

Groups of rats and guinea pigs with normal lungs and others with elastase-induced emphysema were exposed to NH4NO3 aerosols of 0.60 mass median aerodynamic diameter at 1 mg/m3 for 6 hr/day, 5 days/week, for 4 weeks. Morphologic and morphometric studies were performed on lungs perfused with cacodylate-buffered 2% glutaraldehyde under 20 cm H2O pressure at necropsy. The tissues were studied for pathologic change by light and electron microscopy; emphysema was evaluated by subgross and microscopic methods, including changes in mean alveolar chord length using scanning electron microscopy techniques. Elastase produced emphysema to a degree quantifiable by all criteria studied; however, it apparently obscured the effects of nitrate inhalation. The NH4NO3 exposure (compared to air alone) tended to increase values for pulmonary parameters in normal animals of both species and to decrease them in elastase-treated animals. The NH4NO3 exposure increased values for lung volume in rats, percentage area affected in elastase-treated rats, and chord length beta in normal animals of both species. The responses to NH4NO3 were slight (P less than 0.10) and were not accompanied by any detectable changes in alveolar structure. Therefore, the effects of NH4NO3 at this exposure level and duration, are regarded as biologically insignificant for rats and guinea pigs.

Pulmonary function in elastase-treated guinea pigs and rats exposed to ammonium sulfate or ammonium nitrate aerosols.

Three weeks following intratracheal instillations of elastase dissolved in saline, or saline alone, guinea pigs and rats were exposed for 5 or 20 days, 6 hr/day, 5 days/week to filtered room air, 1 mg/m3 ammonium sulfate [NH4)2SO4) or 1 mg/m3 ammonium nitrate (NH4NO3) aerosols. Pulmonary function evaluations conducted in guinea pigs showed no detrimental effects of (NH4)2SO4 or NH4NO3 exposure and very little effect of elastase treatment. Lung function changes in elastase-treated rats were consistent with a condition of experimentally induced pulmonary emphysema. Rats exposed to NH4NO3 aerosols showed no consistent exposure-related changes. Compared with air-exposed animals, rats exposed to (NH4)2SO4 aerosols had increased values of residual volume and functional residual capacity and decreased slope of single-breath N2 washout curves. We conclude that elastase treatment had no significant effect on lung function changes resulting from inhalation of (NH4)2SO4 aerosols. Lung function was more affected by (NH4)2SO4 exposure than by NH4NO3 exposure, and lung function changes were more pronounced in rats than in guinea pigs.

Equine tracheobronchial lavage: comparison of lavage cytologic and pulmonary histopathologic findings.

Differential cell counts were done on bronchial lavage specimens from 166 horses. Postmortem gross and histologic examinations were done to determine the pathologic diagnosis of the lungs from these horses. Ninety-two (55%) were normal, 18 (11%) had interstitial pneumonia, 13 (8%) had bronchopneumonia, 13 (8%) had focal eosinophilia, 11 (7%) had diffuse eosinophilia, 11 (7%) had chronic bronchitis, and 8 (5%) had suppurative bronchitis. Little relationship was found between cellular features of the lavage specimens and the pathologic status of the lungs of individual horses.

Comparison of methods for evaluation of experimentally induced emphysema.

Four methods to quantify induced emphysema, in a manner economically applicable to large numbers of animals, are compared by correlation analyses. Lung tissue used was from rats pretreated intratracheally with elastase or saline prior to exposure to air or (NH4)2SO4 or NH4NO3 aerosols. The most sensitive quantitative evaluation was from mean chord length (MCL) measurements on scanning electron micrographs (SEM). Four-corner and parallel-line grids provided similar results, and reducing sample size to one selected field per lobe yielded a high degree of reliability for MCL measurements. Alveolar-pore perimeter and area (also measured on SEM photographs) were increased by induced emphysema, but were not reliable indicators for degree of pulmonary involvement. Both subjective score (grading the degree of emphysema) and percentage-area-affected determinations indicated the presence of emphysema, but with less sensitivity than MCL measurements. However, these two subgross methods (performed with a dissecting microscope) provided valuable information on the distribution of pulmonary lesions; emphysema was induced in a nonuniform but consistent and progressive pattern in the two lobes of the lung studied.

Effects of ammonium sulfate aerosol exposure on lung structure of normal and elastase-impaired rats and guinea pigs.

Rats and guinea pigs, pretreated with intratracheally administered elastase or saline, were exposed to 1.03 mg/m3 (NH4)2SO4; MMAD, 0.42 micron. Identically treated controls were sham exposed. Measurements and evaluation of structural changes were conducted using morphometric techniques on SEM photographs and by applying subjective ratings. Pathology studies were conducted by light and electron microscopy. All examination methods confirmed elastase-induced emphysema, which was aggravated by (NH4)2SO4 exposure in the rat. Ammonium sulfate exposure of saline-treated animals produced measurable degrees of enlargement of alveoli, and alveolar ducts and sacs. Electron microscopy revealed increased interstitial collagen in affected lung areas of elastase-treated, (NH4)2SO4-exposed animals. Alveolar-pore size was significantly increased in elastase-treated animals (control and exposed) but not in saline-treated, exposed animals. The data suggest a possible difference between elastase and (NH4)2SO4 in the mechanisms responsible for the increased diameter of alveolar structures. Hypertrophy and hyperplasia of nonciliated epithelial cells of the small airways and of the Type II alveolar cells were observed in otherwise untreated guinea pigs exposed to (NH4)2SO4 but not in elastase-treated guinea pigs, nor in any of the rats.

Experimental pulmonary emphysema induced in the rat by intratracheally administered elastase: morphogenesis.

Emphysema was produced experimentally in rats by administration of porcine pancreatic elastase at dose levels of 75, 100, 125, and 150 units elastase activity/100 g body wt. All doses studied were equally effective in producing emphysema. Dose levels of over 75 units activity/100 g offered no advantage in terms of degree or severity of emphysema produced; however, such doses exacerbated hemorrhage and edema, resulting in relatively high post-instillation mortality. Lesion morphogenesis at all doses tested paralleled those described in this and in other species by other investigators. The 75-unit activity produced a quantifiable degree of emphysema which was relatively constant among animals. Results suggest that because of group differences in susceptibility to elastase (or variations in batches of elastase), dose-range studies should be performed on each new group of animals.

Pathogenicity of inhaled nickel compounds in hamsters.

To investigate the pathogenicity of nickel oxide (NiO), hamsters received life-span exposures to that compound (approximately 55 mg/m3) seven hours per day, five days per week. Heavy pulmonary nickel oxide burdens resulted in pneumoconiosis but in no significant carcinogenicity, specific toxicity, or mortality. Two-month exposures of hamsters to nickel-enriched fly ash (NEFA) or fly ash (FA) aerosols (approximately 185 mg/m3) resulted in a deep lung burden of about 5.7 mg, dark discoloration of lungs, heavily dust-laden macrophages, and significantly higher lung weights than in controls, but only minimal inflammatory reaction and no deaths. The NEFA contained 9% nickel; FA contained 0.03% nickel. Exposure to aerosols of NEFA (70 or 15 mg/m3; 6% nickel) or FA (70 mg/m3; 0.3% nickel) for 20 months had no effect on body weight or life-span of the animals. Lung weights and volumes of the high-NEFA- and FA-exposed animals were higher than those of the low-NEFA group and controls. The incidence and severity of interstitial reaction and bronchiolization were significantly higher in the dust-exposed groups than in the controls. The severity of dust deposition, interstitial reaction, and bronchiolization was significantly lower in the low-NEFA group than in the high-NEFA and FA groups. Our findings revealed no significant nickel-specific toxicity/carcinogenicity in hamsters exposed to aerosols of nickel oxide or NEFA, but exposure to high concentrations of the oxide resulted in nonspecific dust pneumoconiosis.

Pathologic effects in rodents exposed to sodium combustion products.

Three species of rodents exhibited respiratory distress when exposed to aerosols of sodium combustion products, the major constituent of which was shown to be sodium carbonate. At the higher doses, animals died during or shortly after 2 hr exposures. Lesions, primarily involving the pharynx and larynx, included accumulation of mucus, vesiculation, and mucosal edema. Other lesions included edema and vesiculation of the anterior trachea, hemorrhage in the lungs, and severe gastric tympany. Basal epithelial cells of the posterior pharynx and anterior trachea had enlarged mitochondria following exposures of 1 hr or more.

Hematologic and immunologic effects of pulsed microwaves in mice.

Mice were exposed in the far field in an anechoic chamber to 2,880-MHz pulsed microwaves 3 to 7.5 h daily, 5 days/week for 60 to 360 h. Three experiments were performed at average power densities of 5 mW/cm2 and six at 10 mW/cm2, corresponding to averaged specific absorption rates (SARs) of 2.25 and 4.50 mW/g, respectively. Each experiment consisted of eight mice, with a concurrently sham-exposed group of eight. In two of three studies at 5 mW/cm2, there was a significant increase in bone marrow cellularity in the microwave-exposed groups compared to the sham-exposed groups. Significant differences were occasionally seen in erythrocyte, leukocyte, and platelet values from microwave-exposed groups, but were not consistently observed. In one of six groups exposed at 10 mW/cm2, mean bone marrow cellularity was reduced significantly in the microwave-exposed mice; in another group, the lymphocyte count was increased. In only one exposure (10 mW/cm2 for 360 h) was any significant effect noted on serum proteins: a reduction to 5.1 +/- 0.3 g/dl in the exposed versus 5.6 +/- 0.4 g/dl in the sham-exposed mice. This was due to a decrease in alpha and beta globulins, with no effect on albumin or gamma globulin concentrations. No effect on bone marrow granulocyte/macrophage colony-forming units (CFU) was revealed following exposure of mice to pulsed microwaves at 5 mW/cm2. In one of four exposures at 10 mW/cm2, there was a significant increase in CFU-agar colonies. No significant effects of exposures at 10 mW/cm2 were observed on in vivo and in vitro assays of cell-mediated immune functions. No exposure-related histopathologic lesions were found from examination of several tissues and organs. Results of these series of exposures of mice at SARs of 2.25 and 4.50 mW/g indicated no consistent effects on the hematologic, immunologic, or histopathologic variables examined.

Effects of inhaled diesel emissions and coal dust in rats.

Rats were exposed to coal dust and diesel exhaust emissions, separately and in combination, for 20 months to evaluate the potential health effects of these specific mine air materials. The diesel exhaust was produced by an engine operated in a load, no-load mode and acceleration, deceleration cycle. It was also modified to simulate an inefficiently tuned engine. Exposure to coal dust was performed in a whole-body rodent inhalation system. Mortality, body weight and hematologic parameters examined were normal compared with those of control rats. Lesions observed were primarily restricted to the lungs and were similar to those described for simple coal workers' pneumoconiosis (CWP). Lesion progression and severity was related to exposure duration and exposure material. Alveolar bronchiolization, though not reported in human CWP, was present in the lungs of some rats in all exposure groups except the control animals.

Chronic inhalation of cobalt oxide and cigarette smoke by hamsters.

Exposure of hamsters to CoO aerosol (10 g/L, 7 hrs./day, 5 days/week) caused pneumoconiosis but affected neither the life span nor the incidence of other than pneumoconiotic lesions. No carcinogenic effects of CoO were observed. While cigarette smoke exposures significantly increased the incidence of certain types of other than pneumoconiotic lesions including tumors, they also increased the life span of the smoke-exposed animals significantly. The latter phenomenon may account for the higher tumor incidence in the smoke-exposed animals. No effect of the smoke exposures on incidence and degree of pneumoconiosis was observed. The mean body weights of the smoke-exposed groups were significantly reduced.

Increased life span and decreased weight in hamsters exposed to cigarette smoke.

Five groups of fifty-one 2-month-old male Syrian golden hamsters received three 10-minute exposures to cigarette smoke per day, 5 days per week, for the duration of their lives. Three of the groups were also chronically exposed to aerosols of chrysotile asbestos, cobalt oxide, and nickel oxides, respectively. The fourth group received twelve weekly injections of 0.25 mg of diethylnitrosamine. The smoke-exposed groups lived significantly (P less than .01) longer than their sham-exposed cohorts and untreated controls. Their mean body weights were significantly (P less than .01) lower than in the sham-exposed groups. The hypothesis is proposed that delayed onset of amyloidosis and lower body weight in the smoke-exposed hamsters may have been responsible for their increased life spans. It is hypothesized that cigarette smoke affected the immune system of the animals, resulting in retardation of amyloidosis, a frequent cause of death in hamsters.

Effects of diethylnitrosamine and cigarette smoke on hamsters.

One hundred two 2-month-old male Syrian hamsters received 12 weekly sc injections of 0.25 mg diethylnitrosamine (DEN). Half the animals were also exposed for 10 minutes to cigarette smoke in Hamburg II-type smoking machines, three times per day, 5 days per week, for their life-span. The other half received sham exposure. Two additional groups of 51 hamsters each, serving as controls, received either only smoke or sham smoke exposures. The DEN treatment resulted in a significant increase (P less than 0.01) in epithelial lesions of the larynx, including laryngeal papillomas. Cigarette smoke inhalation had a significant (P less than 0.01) potentiating effect on the incidence of these lesions. We did not observe the high incidence of tumors of the nasal cavity, trachea, and the lower respiratory tract, or a significant development of malignant tumors, reported by several other investigators. The life-spans of the animals were unaffected by DEN and significantly increased (P less than 0.01) by exposure to smoke. The smoke-exposed groups had significantly lower mean body weights than their sham smoke-exposed cohorts.