Sorghum Dust Research Articles

Distribution of osmophilic and halophilic fungi in combine harvester sorghum dust particles from Egypt

Fifty-two osmophilic (or osmotolerant) and halophilic (or halotolerant) species and one variety representing 24 genera were encountered from 20 combine harvester sorghum dust samples collected from four Covernorates in Upper Egypt, on 50% sucrose - and 15% NaCl-Czapck's agar at 28°C. The results obtained on the two media were basically similar, but numerous fungi could not tolerate 15% NaCl. The most frequent genera were <i>Aspergillus Eurotium, Penicillium</i> and <i>Cladosporium</i>.

Production and Characterization of Hybrid Briquette from Biomass

In this study, production and characterization of hybrid biomass briquettes using two major agricultural wastes was carried out. Briquettes were produced from sawdust of the specie Albiziazygia and sorghum dust using native cassava starch as binder. Five different composition of sawdust/sorghum dust hybrid briquette were produced, moisture content, compressive test, ash content, calorific test and burning efficiency tests were carried to determine the physical and mechanical properties of the hybrid briquette. Test results show that moisture content varies from 6.83% to 29.70%, compressive load at break varies from 4.94KN to 15.18KN, ash content varies from 2.85% to 17.14%, calorific value varies from 3.83MJ/kg to 10.43MJ/kg and burning efficiency varies from 1.57% to 6.63%.

Dexamethasone attenuates grain sorghum dust extract-induced increase in macromolecular efflux in vivo

The purpose of this study was to determine whether dexamethasone attenuates grain sorghum dust extract-induced increase in macromolecular efflux from the in situ hamster cheek pouch and, if so, whether this response is specific. By using intravital microscopy, we found that an aqueous extract of grain sorghum dust elicited significant, concentration-dependent leaky site formation and increase in clearance of FITC-labeled dextran (FITC-dextran; mol mass, 70 kDa) from the in situ hamster cheek pouch (P < 0.05). This response was significantly attenuated by dexamethasone (10 mg/kg iv). Dexamethasone also attenuated substance P-induced leaky site formation and increase in clearance of FITC-dextran from the cheek pouch but had no significant effects on adenosine-induced responses. Dexamethasone had no significant effects on arteriolar diameter in the cheek pouch. On balance, these data indicate that dexamethasone attenuates grain sorghum dust extract- and substance P-induced increases in macromolecular efflux from the in situ hamster cheek pouch in a specific fashion.

Grain sorghum dust increases macromolecular efflux from the in situ nasal mucosa.

The purpose of this study was to determine whether an aqueous extract of grain sorghum dust increases macromolecular efflux from the nasal mucosa in vivo and, if so, whether this response is mediated, in part, by substance P. Suffusion of grain sorghum dust extract on the in situ nasal mucosa of anesthetized hamsters elicits a significant increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass, 70 kDa; P < 0.05). This response is significantly attenuated by CP-96345 and RP-67580, two selective, but structurally distinct, nonpeptide neurokinin 1 (substance P)-receptor antagonists, but not by CP-96344, the 2R,3R enantiomer of CP-96345 (P < 0.05). CP-96345 has no significant effects on adenosine-induced increase in clearance of FITC-dextran from the in situ nasal mucosa. CP-96345 and RP-67580, but not CP-96344, significantly attenuate substance P-induced increases in clearance of FITC-dextran from the in situ nasal mucosa (P < 0.05). Collectively, these data suggest that grain sorghum dust elicits neurogenic plasma exudation from the in situ nasal mucosa.

Neurogenic plasma exudation mediates grain dust-induced tissue injury in vivo.

The purpose of this study was to determine whether an aqueous extract of grain sorghum dust (GDE) elicits neurogenic plasma exudation in the oral mucosa in vivo. Using intravital microscopy, we found that GDE elicited significant, concentration-dependent leaky site formation and an increase in clearance of fluorescein isothiocyanate-labeled dextran (FITC-dextran; mol mass 70 kDa) from the hamster cheek pouch (P < 0.05). The selective, nonpeptide neurokinin(1) (substance P) receptor antagonists, CP-96,345 and RP-67580, but not the 2R,3R enantiomer CP-96,344, significantly attenuated GDE-induced leaky site formation and increase in clearance of FITC-dextran (P < 0.05). Indomethacin had no significant effects on GDE-induced responses. CP-96,345 had no significant effects of adenosine-induced leaky site formation and increase in clearance of FITC-dextran from the cheek pouch. We conclude that GDE elicits neurogenic plasma exudation from the oral mucosa in vivo. We suggest that this process is one mechanism whereby grain sorghum dust elicits immediate oral mucosa inflammation in vivo.

Grain dusts and grain plant components vary in their ability to recruit neutrophils

Occupational exposure to grain dusts can cause bronchitis, particularly to grain sorghum dust. Bronchitis is associated with the presence of increased numbers of neutrophils. To determine how grain dusts could cause neutrophil recruitment to the airways, extract of whole-grain sorghum, corn, and soybean dusts and of pulverized components of these plants were made with Hanks balanced salt solution (HBSS) and used in direct neutrophil chemotaxis experiments. The glume of the grain sorghum plant, the structure holding the seeds in place, caused the migration of the greatest number of neutrophils compared to HBSS [132 +/- 7 vs. 60 cells/high-power field (hpf) +/- 2 SEM, p < .001], followed by whole-grain sorghum dust (121 +/- 5 cells/hpf). Next, bovine bronchial epithelial cells (BBECs) were obtained from fresh lungs and grown to near confluence before challenge with a 10% solution of grain dust and grain plant extracts. The grain sorghum glume and whole-grain sorghum dusts caused release of the greatest amount of neutrophil chemotactic activity (NCA) from BBECs compared to the medium M199 negative control (141 +/- 6 and 153 +/- 7, respectively, vs. 64 cells/hpf +/- 3 SEM, p < .001). The ability to cause neutrophils to migrate by direct and indirect means did not correlate with levels in the grain dusts of endotoxin, which is known to cause release of NCA from bronchial epithelial cells. Therefore, this article describes additional mechanisms by which grain dusts can cause pulmonary inflammation and that are independent of endotoxin levels.

Neutrophilic Respiratory Tract Inflammation and Peripheral Blood Neutrophilia After Grain Sorghum Dust Extract Challenge

To determine if inhalation of grain sorghum dust in the laboratory would cause neutrophilic upper and lower respiratory tract inflammation in human volunteers, as well as systemic signs of illness. Prospective. University of Nebraska Medical Center. Thirty normal volunteers. Inhalation challenge with 20 mL of a nebulized solution of filter-sterilized grain sorghum dust extract (GSDE). One group received prednisone, 20 mg for 2 days, prior to the challenge. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 24 h after challenge, with samples collected as bronchial and alveolar fractions. Findings included visible signs of airways inflammation, quantified as the bronchitis index. The percentage of bronchial neutrophils was significantly increased in those challenged with GSDE vs the control solution, Hanks' balanced salt solution (40.3 +/- 4.5% vs 14.3 +/- 5.1%, p < or = .01). Similar findings were seen in the alveolar fraction. Pretreatment with corticosteroids did not prevent the rise in neutrophils recovered by BAL. Peripheral blood neutrophils were also increased in volunteers challenged with the grain dust extract. To explain the increase in peripheral blood neutrophil counts, the capacity of the peripheral blood neutrophils to migrate in chemotaxis experiments was examined. The results demonstrate an increase in peripheral blood neutrophils and an increase in chemotactic responsiveness. Inhalation challenge with a grain dust extract causes respiratory tract inflammation and a peripheral blood neutrophilia. One reason for this may be an increase in activated peripheral blood neutrophils.

Highly mosquitocidal isolates of Bacillus thuringiensis subspecies kenyae and entomocidus from Mexico

Isolates of Bacillus thuringiensis ssp. kenyae and B. thuringiensis ssp. entomocidus that produce highly mosquitocidal parasporal bodies similar to those produced by B. thuringiensis ssp. israelensis have been obtained from, respectively, sorghum dust and soil samples in Mexico. The parasporal bodies of both isolates are spherical, contain several inclusions enveloped in a fibrous matrix, and are composed of proteins of 27, 65, 128 and 134 kDa which cross-react with polyclonal antisera made against the parasporal body of B. thuringiensis ssp. israelensis. Southern hybridization analyses of the plasmid complements of these new isolates using the cryIVD gene as a probe show that this gene is located on a plasmid of about 110 kb, the same size as the plasmid that bears the cytA, cryIVA, cryIVB and cryIVD genes in B. thuringiensis ssp. israelensis. These results demonstrate that the 110 kb plasmid bearing these insecticidal genes occurs in ecologically diverse habitats as well as in different subspecies of B. thuringiensis. Moreover, the latter finding in conjunction with previous studies shows further that the serotype/subspecies designation used to classify isolates of this bacterium is not a definitive indicator of the insecticidal spectrum of activity.

DETERMINATION OF GRAIN DUST EXPLOSIBILITY PARAMETERS

ABSTRACT Three fractions of wheat and grain sorghum dust were tested at five concentrations for explosibility. Explosibility of one lignite dust fraction was determined as a reference. Parameters determined were minimum explosive concentration, minimum ignition temperature, maximum pressure, and maximum rate of pressure rise. Minimum explosive concentration tests demonstrated that currently accepted minimum explosive concentrations are lower than actual concentrations required for propagation of an explosion. Differences between maximum pressure and maximum rate of pressure rise for primary and secondary chambers demonstrated that a secondary explosion occurred in the secondary chamber. Since residual dust was not initially present in the secondary chamber, fuel for the secondary explosion had to have been transported by the pressure front from the primary chamber. This event demonstrated that residual dust is not essential for occurrence of secondary explosions. KEYWORDS. Grain dust, Explosibility.

Mechanisms of neutrophil recruitment to the lung by grain dust exposure.

Inhalation of grain dusts can cause symptoms of both acute and chronic bronchitis, which has been associated with a neutrophilic inflammatory response in the lung. Since this influx of neutrophils may potentially result in bronchial injury, mechanisms of neutrophil recruitment to grain dust were examined. Sterile, aqueous grain dust extracts were prepared from settled dusts of grain sorghum, corn, oats, and soybeans. The extracts were evaluated for their ability to directly attract human neutrophils using a blindwell neutrophil chemotaxis assay. Each extract was found to possess significant chemotactic activity compared to control (p less than 0.01). To evaluate if the dusts could attract neutrophils indirectly by activating humoral inflammatory mechanisms, the grain dust extracts were evaluated for their ability to activate the complement system. When incubated with normal human serum, each of the grain dusts caused cleavage of the complement proteins C3 and properdin factor B (PFB). Importantly, the grain dust extracts lead to the generation of C5a, a potent neutrophil chemoattractant generated by complement activation. Since activation of the alveolar macrophage to release chemotactic activity represents an additional indirect mechanism of neutrophil recruitment, an extract from grain sorghum dust was evaluated for its ability to stimulate guinea pig and human alveolar macrophages to release neutrophil chemotactic activity. The results demonstrate that supernatants obtained from alveolar macrophages cultured in the presence of grain sorghum dust extract possessed increased chemotactic activity compared to controls (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Thermal Conductivity and Specific Heat of Grain Dust

ABSTRACT THE bulk thermal conductivity and specific heat of wheat, grain sorghum, and corn dusts were deter-mined at ambient temperature by the line heat source method. The moisture contents of the dust samples rang-ed from 8.8 to 17 percent (w.b.), and the densities rang-ed from 240 to 580 kg/m3. Under those conditions ther-mal conductivities ranged from 0.062 to 0.074 W/(m-°C) for wheat dust, from 0.080 to 0.092 W/(m-°C) for grain sorghum dust, and from 0.086 to 0.101 W/(m-°C) for corn dust. Specific heat ranged from 1900 to 2200 J/(kg*°C) for all three types of dust. The thermal con-ductivity of each type of dust increased linearly with moisture content and density. The specific heat of each type of dust increased linearly with moisture content.