Effect of Soil Temperature on Reproduction of Root-knot Nematodes in Flue-cured Tobacco with Homozygous Rk1 and/or Rk2 Resistance Genes.

Most commercial flue-cured tobacco cultivars contain the Rk1 resistance gene, which provides resistance to races 1 and 3 of Meloidogyne incognita and race 1 of M. arenaria. A number of cultivars now possess a second root-knot resistance gene, Rk2. High soil temperatures have been associated with a breakdown of root-knot resistance genes in a number of crops. Three greenhouse trials were performed from 2014 to 2015 investigate the effect of high soil temperature on the efficacy of Rk1 and/or Rk2 genes in reducing parasitism by a population of M. incognita race 3. Trials were arranged in randomized complete block design in open-top growth chambers set at 25°, 30°, and 35°C. Plants were inoculated with 3,000 eggs and data were collected 35 days post-inoculation. Galling, numbers of egg masses and eggs, and reproductive index were compared across cultivar entries. Nematode reproduction was reduced at 25°C and 30°C on entries possessing Rk1 and Rk1Rk2 compared to the susceptible entry and the entry possessing only Rk2. However, there were often no significant differences in reproduction at 35°C between entries with Rk1 and/or Rk2 compared to the susceptible control, indicating an increase of root-knot nematode parasitism on resistant entries at higher temperatures. Although seasonal differences in nematode reproduction were observed among experiments, relative differences among tobacco genotypes remained generally consistent.

Reproduction of Meloidogyne arenaria race 2 on flue-cured tobacco with putative resistance derived from Nicotiana repanda.

Chemical controls for root-knot nematodes are increasingly restricted due to environmental and human health concerns. Host resistance to these nematodes is key to flue-cured tobacco production in Virginia. Resistance to Meloidogyne incognita races 1 and 3, and race 1 of M. arenaria is imparted by the gene Rk1, which is widely available in commercial flue-cured tobacco. Rk2 imparts increased resistance to M. javanica when stacked with Rk1 and is becoming commercially available. The efficacy of Rk2 against M. arenaria race 2, which is increasingly prevalent in Virginia, is unclear. Greenhouse trials were conducted in 2017 to determine how potential resistance derived from N. repanda compares to the root-knot nematode resistance afforded by Rk1 and Rk2. Trials were arranged in a completely randomized block design and included an entry with traits derived from N. repanda, a susceptible entry and entries possessing Rk1 and/or Rk2. Data collected after 60 days included percent root galling, egg mass counts, and egg counts. Root galling and reproduction were significantly lower on the entry possessing traits derived from N. repanda relative to other entries, suggesting that the N. repanda species may hold a novel source of root-knot nematode resistance for commercial flue-cured tobacco cultivars.

Reproduction of Meloidogyne arenaria race 2 on Flue-cured tobacco possessing resistance genes Rk1 and/or Rk2.

Resistance to Meloidogyne incognita races 1 and 3 and race 1 of M. arenaria is imparted to flue-cured tobacco by the gene Rk1. Meloidogyne arenaria race 2 is not controlled by Rk1 and has become prevalent in Virginia. A second form of resistance effective against M. javanica, Rk2, is also increasingly available commercially. Greenhouse and field trials including a root-knot susceptible cultivar, cultivars homozygous for Rk1 or Rk2, and cultivars possessing both genes were conducted in 2018 and 2019 to investigate the effect of Rk1 and/or Rk2 on parasitism and reproduction of M. arenaria race 2. Plants were inoculated with 5,000 M. arenaria race 2 eggs in the greenhouse or infested by a native nematode population in the field. Data were collected after 28 days (greenhouse) or every 3 weeks following transplant until 18 weeks in the field and included root galling index, nematodes present in roots, egg mass numbers, and egg counts; reproductive indices were also calculated. We found that the combination of Rk1 and Rk2 provides greater resistance to M. arenaria race 2 than either gene alone. While the effect of either gene alone was inconsistent, we did observe some significant reductions in galling and reproduction associated with each gene relative to the susceptible control.

Validation of the Strawberry Advisory System in the Mid-Atlantic Region.

Anthracnose fruit rot (AFR) and Botrytis fruit rot (BFR) are primary diseases affecting strawberry (Fragaria × ananassa), which typically drive fungicide applications throughout the growing season. The Strawberry Advisory System (StAS), a disease forecasting tool, was originally developed in Florida to better time the fungicide sprays by monitoring AFR and BFR infection risk based on leaf wetness and temperature input in real-time. Thirteen field trials were conducted in Maryland and Virginia between 2017 and 2019 to evaluate the StAS performance in the Mid-Atlantic region. As a result, 55, 18, and 31% fewer sprays were recorded on average in the model-based StAS treatment compared with the grower standard treatment in 2017, 2018, and 2019, respectively. Marketable yield, as well as AFR and BFR incidence, were largely comparable between the two treatments. However, poor disease control occurred during the StAS treatment in four trials in 2017, presumably because of a missed fungicide spray during a high-risk infection event and attributable to heavy rainfall that led to impassable fields. The implementation of the StAS may be further challenged by the employment of floating row covers that are essential for growing strawberries in plasticulture systems in open fields in the Mid-Atlantic region. Preliminary results indicated that row covers can alter canopy-level microclimatic conditions, possibly increasing the risk for disease occurrence. Overall, the StAS can be a valuable tool for Mid-Atlantic growers to control AFR and BFR, but sprays may need to be promptly applied when consecutive or heavy rainfalls are predicted, especially for highly susceptible cultivars. Complications in disease forecasting and management arising from the use of row covers need to be further addressed in this region because of its highly diverse climate.

Metastasis to the F344 Rat Pancreas from Lung Cancer Induced by 4-(Methylnitrosamino)- 1-(3-pyridyl)-1-butanone and Enantiomers of Its Metabolite 4-(Methylnitrosamino)-1-(3-pyridyl)- 1-butanol, Constituents of Tobacco Products.

Lung cancer is the most common cause of cancer-related deaths in humans worldwide. There is strong evidence that the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) play an important role in carcinogenesis caused by tobacco products. NNK and racemic NNAL are reported to induce lung and pancreatic tumors in rats. The carcinogenicity in Fischer 344 rats of NNK, NNAL, and its enantiomers ( R)-NNAL and ( S)-NNAL has been studied recently, and all test compounds induced significant numbers of lung tumors. We report here the detailed histopathological and immunohistochemical characterization of these tumors and their aggressive nature as shown by their metastasis locally and to the pancreas. The spectrum of treatment-related histopathological findings comprised pulmonary alveolar/bronchiolar (A/B) epithelial hyperplasia, A/B adenomas, and A/B carcinomas. A/B carcinomas frequently exhibited local invasion/metastasis within the mediastinum and thoracic cavity and distant metastasis to the pancreas that was confirmed by immunohistochemistry using the lung-specific markers prosurfactant protein-C and club (Clara) cell-10. Our observation regarding metastasis to the pancreas was an important, and unexpected, finding in this study both for the experimental animal model and potential human relevance.

Reproduction of Meloidogyne incognita Race 3 on Flue-cured Tobacco Homozygous for Rk1 and/or Rk2 Resistance Genes.

Most commercial tobacco cultivars possess the Rk1 resistance gene to races 1 and 3 of Meloidogyne incognita and race 1 of Meloidogyne arenaria, which has caused a shift in population prevalence in Virginia tobacco fields toward other species and races. A number of cultivars now also possess the Rk2 gene for root-knot resistance. Experiments were conducted in 2013 to 2014 to examine whether possessing both Rk1 and Rk2 increases resistance to a variant of M. incognita race 3 compared to either gene alone. Greenhouse trials were arranged in a completely randomized design with Coker 371-Gold (C371G; susceptible), NC 95 and SC 72 (Rk1Rk1), T-15-1-1 (Rk2Rk2), and STNCB-2-28 and NOD 8 (Rk1Rk1 and Rk2Rk2). Each plant was inoculated with 5,000 root-knot nematode eggs; data were collected 60 d postinoculation. Percent galling and numbers of egg masses and eggs were counted, the latter being used to calculate the reproductive index on each host. Despite variability, entries with both Rk1 and Rk2 conferred greater resistance to a variant of M. incognita race 3 than plants with Rk1 or Rk2 alone. Entries with Rk1 alone were successful in reducing root galling and nematode reproduction compared to the susceptible control. Entry T-15-1-1 did not reduce galling compared to the susceptible control but often suppressed reproduction.

Carcinogenicity and DNA adduct formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and enantiomers of its metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol in F-344 rats.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is metabolized to enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), found in the urine of virtually all people exposed to tobacco products. We assessed the carcinogenicity in male F-344 rats of (R)-NNAL (5 ppm in drinking water), (S)-NNAL (5 ppm), NNK (5 ppm) and racemic NNAL (10 ppm) and analyzed DNA adduct formation in lung and pancreas of these rats after 10, 30, 50 and 70 weeks of treatment. All test compounds induced a high incidence of lung tumors, both adenomas and carcinomas. NNK and racemic NNAL were most potent; (R)-NNAL and (S)-NNAL had equivalent activity. Metastasis was observed from primary pulmonary carcinomas to the pancreas, particularly in the racemic NNAL group. DNA adducts analyzed were O (2)-[4-(3-pyridyl)-4-oxobut-1-yl]thymidine (O (2)-POB-dThd), 7-[4-(3-pyridyl)-4-oxobut-1-yl]guanine(7-POB-Gua),O (6)-[4-(3-pyridyl)-4-oxobut-1-yl]deoxyguanosine(O (6)-POB-dGuo),the 4-(3-pyridyl)-4-hydroxybut-1-yl(PHB)adductsO (2)-PHB-dThd and 7-PHB-Gua, O (6)-methylguanine (O (6)-Me-Gua) and 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB)-releasing adducts. Adduct levels significantly decreased with time in the lungs of rats treated with NNK. Pulmonary POB-DNA adducts and O (6)-Me-Gua were similar in rats treated with NNK and (S)-NNAL; both were significantly greater than in the (R)-NNAL rats. In contrast, pulmonary PHB-DNA adduct levels were greatest in the rats treated with (R)-NNAL. Total pulmonary DNA adduct levels were similar in (S)-NNAL and (R)-NNAL rats. Similar trends were observed for DNA adducts in the pancreas, but adduct levels were significantly lower than in the lung. The results of this study clearly demonstrate the potent pulmonary carcinogenicity of both enantiomers of NNAL in rats and provide important new information regarding DNA damage by these compounds in lung and pancreas.

A concomitant loss of dormant origins and FANCC exacerbates genome instability by impairing DNA replication fork progression.

Accumulating evidence suggests that dormant DNA replication origins play an important role in the recovery of stalled forks. However, their functional interactions with other fork recovery mechanisms have not been tested. We previously reported intrinsic activation of the Fanconi anemia (FA) pathway in a tumor-prone mouse model (Mcm4chaos3) with a 60% loss of dormant origins. To understand this further, we introduced a null allele of Fancc (Fancc-), encoding a member of the FA core complex, into the Mcm4chaos3 background. Primary embryonic fibroblasts double homozygous for Mcm4chaos3 and Fancc- (Mcm4chaos3/chaos3;Fancc-/-) showed significantly increased levels of markers of stalled/collapsed forks compared to either single homozygote. Interestingly, a loss of dormant origins also increased the number of sites in which replication was delayed until prophase, regardless of FA pathway activation. These replication defects coincided with substantially elevated levels of genome instability in Mcm4chaos3/chaos3;Fancc-/- cells, resulting in a high rate of perinatal lethality of Mcm4chaos3/chaos3;Fancc-/- mice and the accelerated tumorigenesis of surviving mice. Together, these findings uncover a specialized role of dormant origins in replication completion while also identifying important functional overlaps between dormant origins and the FA pathway in maintaining fork progression, genome stability, normal development and tumor suppression.

CD8+ T cell-independent tumor regression induced by Fc-OX40L and therapeutic vaccination in a mouse model of glioma.

Despite the growing number of preclinical and clinical trials focused on immunotherapy for the treatment of malignant gliomas, the prognosis for this disease remains grim. Although some promising advances have been made, the immune response stimulated as a result of immunotherapeutic protocols has been inefficient at complete tumor elimination, primarily due to our lack of understanding of the necessary effector functions of the immune system. We previously demonstrated that a tumor lysate vaccine/Fc-OX40L therapy is capable of inducing enhanced survival and tumor elimination in the GL261 mouse glioma model. The following experiments were performed to determine the mechanism(s) of action of this therapy that elicits a potent antitumor immune response. The evidence subsequently outlined indicates a CD8(+) T cell-independent and CD4(+) T cell-, NK cell-, and B cell-dependent means of prolonged survival. CD8(+) T cell-independent tumor clearance is surprising considering the current focus of many cancer immunotherapy protocols. These results provide evidence for CD8(+) T cell-independent means of antitumor response and should lead to additional examination of the potential manipulation of this mechanism for future treatment strategies.

Helq acts in parallel to Fancc to suppress replication-associated genome instability.

HELQ is a superfamily 2 DNA helicase found in archaea and metazoans. It has been implicated in processing stalled replication forks and in repairing DNA double-strand breaks and inter-strand crosslinks. Though previous studies have suggested the possibility that HELQ is involved in the Fanconi anemia (FA) pathway, a dominant mechanism for inter-strand crosslink repair in vertebrates, this connection remains elusive. Here, we investigated this question in mice using the Helq(gt) and Fancc(-) strains. Compared with Fancc(-)(/)(-) mice lacking FANCC, a component of the FA core complex, Helq(gt/gt) mice exhibited a mild of form of FA-like phenotypes including hypogonadism and cellular sensitivity to the crosslinker mitomycin C. However, unlike Fancc(-)(/)(-) primary fibroblasts, Helq(gt/gt) cells had intact FANCD2 mono-ubiquitination and focus formation. Notably, for all traits examined, Helq was non-epistatic with Fancc, as Helq(gt)(/gt);Fancc(-)(/)(-) double mutants displayed significantly worsened phenotypes than either single mutant. Importantly, this was most noticeable for the suppression of spontaneous chromosome instability such as micronuclei and 53BP1 nuclear bodies, known consequences of persistently stalled replication forks. These findings suggest that mammalian HELQ contributes to genome stability in unchallenged conditions through a mechanism distinct from the function of FANCC.

(S)-N'-Nitrosonornicotine, a constituent of smokeless tobacco, is a powerful oral cavity carcinogen in rats.

Currently, smokeless tobacco products are being proposed as an alternative mode of tobacco use associated with less harm. All of these products contain the tobacco-specific carcinogen N'-nitrosonornicotine (NNN). The major form of NNN in tobacco products is (S)-NNN, shown in this study to induce a total of 89 benign and malignant oral cavity tumors in a group of 20 male F-344 rats treated chronically with 14 p.p.m. in the drinking water. The opposite enantiomer (R)-NNN was weakly active, but synergistically enhanced the carcinogenicity of (S)-NNN. Thus, (S)-NNN is identified for the first time as a strong oral cavity carcinogen in smokeless tobacco products and should be significantly reduced or removed from these products without delay in order to prevent debilitating and deadly oral cavity cancer in people who use them.

Persistent enteric mycobacterial infection enhances sensitivity to acute mucosal injury.

Antigen presenting cells such as intestinal macrophages are dynamic effector cells that play a critical role in maintaining mucosal homeostasis. However, it is not known how occult intestinal infections alter the response of the intestinal mucosa to subsequent intestinal injury. The aim of this study was to evaluate how persistent subclinical intestinal infection with Mycobacterium avium subsp. paratuberculosis (Map) would influence acute dextran sulfate sodium (DSS)-mediated intestinal inflammation. BALB/c mice were infected intraperitoneally with Map. Following an incubation period of 90 d, mice were administered 2% DSS in the drinking water for six days. Prior to and during treatment with DSS, mice were evaluated for clinical signs of disease and body weights were recorded. At termination of the experiment, body weights, frequency of rectal blood, and gross and histological cecal lesions were evaluated, and tissues were collected for isolation of Map. Subclinical and persistent intestinal Map infection was established based on the absence of both weight loss and rectal blood and the isolation of Map from the small and large intestines in mice infected with Map only. Following treatment with DSS, Map-infected mice had increased weight loss, increased frequency of rectal blood, and exacerbation of gross lesions and increased cecal lesion scores. Also, there was a significant reduction in Map isolated from the small intestines of Map-infected and DSS-treated mice. In conclusion, subclinical Map infection sensitizes the host to enhanced acute DSS-mediated intestinal inflammation.

Extracutaneous neutrophilic inflammation in a dog with lesions resembling Sweet's Syndrome.

A 7-year-old-spayed female standard poodle dog presented to the Iowa State University Veterinary Teaching Hospital with an 8-day history of lethargy, left hind limb lameness, ptyalism and peripheral lymphadenomegaly. On physical examination, the dog was lethargic, febrile (40.5 degrees C) and had multifocal to coalescing erythematous papular to pustular eruptions on the skin of all four limbs, periocularly and on the ventral and lateral thorax and abdomen. Histopathological findings from skin biopsies of the papules revealed a severe diffuse neutrophilic dermatitis with sub- and intra-epithelial pustules. Four days after being admitted the dog died from cardiac and respiratory failure. At necropsy, in addition to the multifocal to coalescing erythematous papules, the skin contained scattered pustules. Additionally, the subcutaneous tissue surrounding the right stifle was diffusely oedematous, and the peripheral and visceral lymph nodes were enlarged. The predominant histologic lesion was neutrophilic inflammation, in the absence of detectable bacteria in the skin, heart, lungs, oesophagus and left tarsus. In the absence of neoplasia or bacteraemia, a syndrome similar to Sweet's Syndrome should be considered as a differential diagnosis in dogs with cutaneous and extracutaneous neutrophilic infiltrates.

Biological and chemical induction of resistance to the Globodera tabacum solanacearum in oriental and flue-cured tobacco (Nicotiana tabacum L.).

The effects of acibenzolar-S-methyl (ASM) and four combinations of plant growth-promoting rhizobacteria (PGPR) on the reproduction of a tobacco cyst nematode, Globodera tabacum solanacearum, and growth of Nicotiana tabacum (cv. K326 and Xanthi) were tested under greenhouse and field conditions. The PGPR included combinations of Bacillus subtilis A13 with B. pumilis INR7, B. pumilis SE34, B. licheniformis IN937b, or B. amyloliquefaciens IN937a, respectively. Among the four rhizobacterial combinations, IN937a + A13 exhibited the most consistent reduction in G. t. solanacearum cysts under greenhouse and field conditions. No undesirable effects of IN937a + A13 were observed on tobacco growth under greenhouse and field conditions. Use of INR7 + A13 reduced G. t. solanacearum reproduction on flue-cured tobacco cv. K326 but not on oriental tobacco cv. Xanthi. Application of ASM reduced final numbers of G. t. solanacearum cysts, but also resulted in phytotoxicity mainly under the greenhouse conditions. When oriental tobacco seedlings were pre-grown in a IN937a + A13-treated soil-less medium, a single application of ASM at 200 mg/L one week after transplanting significantly reduced G. t. solanacearum reproduction in the field.

Effects of Ph gene-associated versus induced resistance to tobacco cyst nematode in flue-cured tobacco.

Effects of the systemic acquired resistance (SAR)-inducing compound acibenzolar-S-methyl (ASM) and the plant-growth promoting rhizobacterial mixture Bacillus subtilis A13 and B. amyloliquefaciens IN937a (GB99+GB122) were assessed on the reproduction of a tobacco cyst nematode (TCN- Globodera tabacum solanacearum) under greenhouse conditions. Two sets of two independent experiments were conducted, each involving soil or root sampling. Soil sample experiments included flue-cured tobacco cultivars with (Ph(p)+: NC71 and NC102) and without (Ph(p)-: K326 and K346) a gene (Ph(p)) suppressing TCN parasitism. Root sample experiments examined TCN root parasitism of NC71 and K326. Cultivars possessing the Ph(p) gene (Ph(p)+) were compared with Ph(p)- cultivars to assess the effects of resistance mediated via Ph(p) gene vs. induced resistance to TCN. GB99+GB122 consistently reduced nematode reproductive ratio on both Ph(p)+ and Ph(p)- cultivars, but similar effects of ASM across Ph(p)- cultivars were less consistent. In addition, ASM application resulted in leaf yellowing and reduced root weight. GB99+GB122 consistently reduced nematode development in roots of both Ph(p)+ and Ph(p)- cultivars, while similar effects of ASM were frequently less consistent. The results of this study indicate that GB99+GB122 consistently reduced TCN reproduction in all flue-cured tobacco cultivars tested, while the effects of ASM were only consistent in Ph(p)+ cultivars. Under most circumstances, GB99+GB122 suppressed nematode reproduction more consistently than ASM compared to the untreated control.

NMR and SANS studies of aggregation and microemulsion formation by phosphorus fluorosurfactants in liquid and supercritical carbon dioxide.

(1)H NMR relaxation and diffusion studies were performed on water-in-CO(2) (W/C) microemulsion systems formed with phosphorus fluorosurfactants of bis[2-(F-hexyl)ethyl] phosphate salts (DiF(8)), having different counterions (Na(+), NH(4)(+), N(CH(3))(4)(+)) by means of high-pressure in situ NMR. Water has a low solubility in CO(2) and is mainly solubilized by the microemulsion droplets formed with surfactants added to CO(2) and water mixtures. There is rapid exchange of water between the bulk CO(2) and the microemulsion droplets; however, NMR relaxation measurements show that the entrapped water has restricted motion, and there is little "free" water in the core. Counterions entrapped by the droplets are mostly associated with the surfactant headgroups: diffusion measurements show that counterions and the surfactant molecules move together with a diffusion coefficient that is associated with the droplet. The outer shell of the microemulsion droplets consists of the surfactant tails with some associated CO(2). For W/C microemulsions formed with the phosphate-based surfactant having the ammonia counterion (A-DiF(8)), the (1)H NMR signal for NH(4)(+) shows a much larger diffusion coefficient than that of the surfactant tails. This apparent paradox is explained on the basis of proton exchange between water and the ammonium ion. The observed dependence of the relaxation time (T(2)) on W(0) (mole ratio of water to surfactant in the droplets) for water and NH(4)(+) can also be explained by this exchange model. The average hydrodynamic radius of A-DiF(8) microemulsion droplets estimated from NMR diffusion measurements (25 degrees C, 206 bar, W(0) = 5) was R(h) = 2.0 nm. Assuming the theoretical ratio of R(g)/R(h) = 0.775 for a solid sphere, where R(g) is the radius of gyration, the equivalent hydrodynamic radius from SANS is R(h) = 1.87 nm. The radii measured by the two techniques are in reasonable agreement, as the two techniques are weighted to measure somewhat different parts of the micelle structure.

Experimental in utero inoculation of late-term swine fetuses with porcine circovirus type 2.

All 37 fetuses of 3 laparotomized pregnant sows at 86, 92, and 93 days of gestation were inoculated intramuscularly through the uterine wall with porcine circovirus type 2 (PCV-2). The sows were allowed to farrow, and blood and tissue samples were collected from their piglets before and after suckling colostrum. Thirteen fetuses from 2 sows at 90 and 103 days of gestation were used as controls. Of the 37 PCV-2 inoculated fetuses, 24 were grossly normal and 13 were mummified, stillborn, or weak-born at farrowing. Infection with PCV-2 was demonstrated in various tissues of grossly normal and abnormal fetuses by virus isolation, polymerase chain reaction, and immunohistochemical methods. Antibodies specific to PCV-2 were also detected from the sera or thoracic fluids of abnormal fetuses and unsuckled normal pigs. No evidence of PCV-2 infection was found in any control fetuses. The present results confirm previous findings that PCV-2 can infect late-term swine fetuses and may cause reproductive abnormalities.

Lecithin microemulsions in dimethyl ether and propane for the generation of pharmaceutical aerosols containing polar solutes.

Water soluble compounds have been incorporated into solution phase metered dose inhalers (MDIs) utilizing lecithin inverse microemulsions in dimethyl ether (DME) and propane. DME and propane acted as both solvent and propellant. Experiments utilizing model propellants (dimethylethyleneglycol (DMEG) and hexane) were used to investigate microemulsion physicochemical phenomena, and the results were used to design and interpret the technically more challenging MDI experiments. NMR and viscosity experiments with model propellants were consistent with a "sphere-to-string" micellar shape change as the solvent was varied from pure DMEG to pure hexane. Water soluble solutes, including selected peptides and fluorescently labeled poly-alpha, beta-[N-(2-hydroxyethyl) D,L-aspartamide] (fPHEAs), dissolved in DME/propane dependent on lecithin and water content. MDIs containing microemulsions generated aerosols with mass median aerodynamic values ranging from 2.7 to 3.1 microns, within the range of commercially available formulations. Fine particle fraction values (50-70%) exceeded those of commercial formulations. fPHEA up to 18 kDa did not adversely affect the aerosol characteristics. Deposition of the aerosol onto a water surface resulted in the formation of liposomes with partially entrapped solute.