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At least 289 records · Page 16Linked to original sources
PubMed2006

[Spatial patterns of Bemisia tabaci (Gennadius) population in cotton fields].

Field investigations on the vertical and horizontal distribution patterns of Bemisia tabaci (Gennadius) population on Bt cotton Guokang No. 22 and non-Bt cotton Simian No. 3 showed that in July, no obvious difference was found in the vertical distribution of B. tabaci population on cotton plant, but in August, the population density was significantly higher on the upper part of cotton plant than on its middle and lower parts. The horizontal distribution patterns of B. tabaci adult and nymph were similar. B. tabaci distributed evenly on cotton leaves when its population density was low, but aggregated when its population density was high. The greater the population density, the higher the aggregation rate was observed. Throughout the incidence stage, B. tabaci adult and nymph aggregated and diffused alternatively. No significant difference was observed in the spatial distribution pattern of B. tabaci on Bt and non-Bt cotton plants.

Animals↗
PubMedDate not supplied

Evaluation of cotton as a carrier for solid-phase peptide synthesis.

Cotton as a new support for the solid-phase synthesis of peptides was evaluated under the conditions of both Boc/Bzl and Fmoc/But strategy. Syntheses of peptides containing only bifunctional amino acids gave comparable results, but peptides containing trifunctional amino acids are clearly advantageously synthesized using the Fmoc approach. The comparison of cotton with other planar carriers (paper or polypropylene membranes) and with classical pellicular ones has shown practical applicability of cotton as the replacement of more sophisticated carriers. N-Methylimidazole was shown to be the optimal acylation catalyst for the modification of the cellulose carrier. Stability of the ester bond to the cotton was studied and shown to be adequate for the syntheses of small to medium size peptides. A relatively low level of substitution of cotton carrier in connection with its ability to soak the solvent was used for the complete elimination of a synthetic vessel. Couplings can be performed by wetting the carrier with the coupling solution, and all solvents can be removed either by squeezing it together with a porous material (paper) or by centrifugation. This leads to a significant decrease of solvent consumption. The efficiency of solvent elimination by centrifugation was demonstrated by the synthesis of model peptide ACP 65-74 in which only one wash between coupling and deprotection and between deprotection and coupling was used and which afforded the product of the same quality as the product synthesized using the standard protocol. Bromophenol blue monitoring has been proven as the optimal way of monitoring the acylation reaction progress. Peptides directly bound to cotton were shown to be useful in enzyme-linked immunosorbent assay tests.

Acylation↗
PubMed1991

[Immunologic findings and ventilatory function in cotton industry workers].

Immunological testing was carried out in 24 cotton workers and in 30 control workers. Skin prick test was performed with allergens prepared from cotton dust and cotton seed. Skin tests were positive in 33.3% and IgE level was increased in 62.5% of the cotton workers. Only two 3.3% had positive skin tests and none had increased IgE serum level. Ventilatory capacity in cotton workers with positive skin tests and those with negative skin tests was comparable. The same was true of the workers with increased and normal IgE levels. The effect of cotton dust extract on isolated tracheal smooth muscle of a guinea pig was an indication of a direct irritative action causing airway obstruction.

Adult↗
PubMed1988

Plant constituents of cotton dust and lung effects after inhalation.

Experiments were performed to assess pulmonary reactions after inhalation of cotton dusts with different levels of tannins, terpenoid aldehydes and bacterial endotoxins. Guinea-pigs were exposed to cotton dust. Free lung cells were obtained by lavage 24 h later. A dose-response relationship was found between the number of neutrophils and the amount of endotoxin in the dust. No influence of terpenoid aldehyde or tannin levels could be detected. Cotton mill workers were exposed to dust from glanded and glandless cottons in an experimental cardroom. The average decreases in forced expiratory volume in one second (FEV1) over the workday after carding the two cottons were the same, although levels of dust, tannin or terpenoid aldehydes were different. The level of airborne endotoxin was, however, equal. The results support observations from other studies on the importance of endotoxin for the development of the acute reactions observed after cotton dust exposure.

Animals↗
PubMed1984

Effect of stimulation and blockade of mononuclear phagocyte system on the treatment of microfilaremia of Litomosoides carinii in the cotton rat and the jird.

The role of mononuclear phagocyte system (MPS) in the effect of diethylcarbamazine (DEC) for clearing microfilariae of Litomosoides carinii from the blood stream was studied in the cotton rat and the jird, using diethylstilbestrol (DES) for the stimulation of MPS and carrageenan (CGN) for the blockade of MPS. The level of microfilaremia was not influenced by administration of DES subcutaneously or CGN intraperitoneally, indicating that the circulating microfilariae in naturally infected animals were affected neither by the activation nor suppression of MPS. DEC-mediated clearance of microfilariae in the cotton rat was remarkably enhanced by the activation of MPS. Unlike the cotton rat, microfilaricidal effect of DEC in the jird was not influenced by pretreatment with DES. This result corresponds to the fact that the phagocytic activity of MPS was enhanced by DES in the cotton rat, but not in the jird. On the other hand, although the phagocytic activity of MPS was depressed by CGN in the cotton rat, there was no distinct change in the effect of DEC both in the cotton rat and the jird by pre-treatment with CGN, suggesting that CGN-mediated blockade of MPS was a transient phenomenon.

Animals↗
PubMed1983

Comparison of activities of mononuclear phagocyte system between the cotton rat, Sigmodon hispidus, and the jird, Meriones unguiculatus, in relation to the treatment of filariasis.

The cotton rat and jird, matched according to age and the period after infection with Litomosoides carinii, were administered intraperitoneally with diethylcarbamazine (DEC) at a single dose of 100 mg/kg. Microfilaria counts were conducted 0.5, 1, and 6 hrs and 1, 4, and 7 days after treatment with DEC. The average of percent microfilaria density was significantly higher in the jird than in the cotton rat at any given time except at 6 hrs, when a slight increase was observed in the cotton rat. To clarify the cause of different microfilaricidal activities of DEC between the cotton rat and jird, function of the mononuclear phagocyte system (MPS) was compared in the two animals by observing clearance of the carbon particles introduced into blood vessels. The amount of remaining carbon in the vessels was always lower in the cotton rat than in the jird from 30 min. on after carbon injection. The clearance index K, which is thought to reflect the phagocytic capability of MPS, was higher in the cotton rat than in the jird. Microscopic examination also showed differences in the amount of carbon phagocytosed by the Kupffer cells of the liver in the two animals. The results indicated that the difference in microfilaricidal effect of DEC may be due to different phagocytic activity of MPS.

Animals↗
PubMed1984

Gram-negative bacterial endotoxins in airborne dusts from washed and unwashed cottons.

Gram-negative bacteria possess lipopolysaccharide-protein complexes termed endotoxins as an integral portion of their cell walls. These biologically active substances elicit profound effects both in vitro and in vivo. Organic dusts from many occupational environments contain measureable amounts of gram-negative bacteria and their endotoxins. In particular, cottons and cotton dusts contain these materials, and research is directed to elucidate the association between endotoxins and the acute and chronic respiratory effects of inhaling cotton dusts. It is the purpose of this paper to describe an experimental process which removes endotoxins from cotton by washing prior to processing the baled cottons. The studies show that water washing is a reliable method for removing endotoxins, and pulmonary function studies correlate well with endotoxin levels in the air. Quantification of airborne endotoxins provides a good indicator of cleanliness and toxocity of the cotton dusts. However, the differential toxicities of different endotoxins must be considered and evaluated further.

Dust↗
PubMed1993

Enterobacter agglomerans--associated cotton fever.

Cotton fever is usually a benign febrile, leukocytic syndrome of unknown etiology seen in intravenous narcotic abusers. Cotton and cotton plants are heavily colonized with Enterobacter agglomerans. We report a case of cotton fever associated with E agglomerans in which the organism was first isolated from the patient's blood and secondarily from cotton that he had used to filter heroin. Enterobacter agglomerans is with most probability the causal agent of cotton fever. Patients presenting with the classic history should have blood cultures performed and should be started on a regimen of empiric antibiotic therapy.

Adult↗
PubMed1993

Alteration in the modulatory role of respiratory epithelium after exposure of guinea pigs to respirable cotton dust.

Chest tightness may occur after inhalation of cotton dust. To understand the origins of this symptom of byssinosis, we exposed guinea pigs to respirable cotton dust and determined whether the resulting pulmonary obstruction was associated with alterations in the in vitro reactivity of the trachea to methacholine. The isolated, perfused trachea preparation was utilized because it allows a comparison of airway smooth muscle responses to drugs after they are applied separately to the mucosal or serosal surfaces. In epithelium-containing control tracheae, mucosally applied methacholine was less potent and elicited smaller maximum contractile responses than those obtained when it was applied to the serosal compartment. After a 6-h inhalation exposure to 30 mg/m3 respirable cotton dust, the mucosal maximum response to methacholine was substantially increased immediately (0 h) after the end of the exposure, but it was decreased 18 h postexposure. A dust level of 10 mg/m3 produced modest increases in the mucosal maximum responses at both postexposure periods, elevating them to the magnitude of the extraluminal maximum response. The potency of serosally applied methacholine was not affected by any cotton dust exposure. Mechanical epithelium removal increased mucosal reactivity to the serosal level in both control and cotton (30 mg/m3)-exposed groups, and abolished the effects of dust on mucosal reactivity to methacholine. Our findings suggest that the modulatory effect of the epithelium may be inhibitory or excitatory. The balance between the two influences may be altered by inhaled cotton dust.

Administration, Inhalation↗
PubMed2026

Selection of GhTT2-A07 promoter enhances fiber quality in improved cotton varieties.

Modern cultivated cotton fibers are predominantly white with enhanced quality compared to their wild ancestors. However, the molecular mechanisms and evolutionary drivers linking fiber color to quality remain least focused. In this study, we identified FQC1 (Fiber Quality and Color 1), a major quantitative trait locus (QTL) on chromosome A07 that concurrently regulates both fiber quality and pigmentation. Through map-based cloning, we revealed that Gossypium hirsutum TRANSPARENT TESTA2-A07 (GhTT2-A07), an R2R3-MYB transcription factor, resides within this locus. GhTT2-A07 modulates fiber development by directly activating genes in the general phenylpropanoid pathway, thereby promoting the metabolic flux toward downstream secondary metabolites. Variations in the GhTT2-A07 promoter led to its reduced expression in modern white cotton cultivars. This down-regulation suppresses the accumulation of S/G/H-type lignin monomers and proanthocyanidins, resulting in altered secondary cell wall composition and ultimately enhancing the quality of mature white fibers. Population genetic analyses further indicate that the white-fiber allele GhTT2-A07W has been fixed in modern breeding genotypes, underscoring the impact of artificial selection during cotton domestication. Overall, our study elucidates the biochemical and molecular mechanisms underlying fiber quality and pigmentation in cotton, clarifies the selection criteria for high-quality white fibers in modern cultivars, and provides a theoretical basis for future targeted genetic improvement of cotton fibers.

Alleles↗
PubMed1964

COTTON CLOSURE AS AN AERATION BARRIER IN SHAKEN FLASK FERMENTATIONS.

Oxygen transfer through a cotton plug follows Fick's law of diffusion. The apparent diffusion constant decreases as the density of cotton packing is increased. Formulas are derived which relate oxygen transfer to cotton-plug dimensions. Calculations indicate that the dimensions of a cotton plug can affect both the maximal oxygen uptake rate and the gas composition inside a shaken flask. In some situations, as with large flasks, the cotton closure can become the limiting factor to aeration.

Bacillus megaterium↗
PubMed1957

Survival of variola virus in raw cotton.

An investigation was carried out to establish the survival period of variola virus in relation to its importation into Great Britain in raw cotton. Under the conditions of the experiments described here, variola virus in scabs from a single patient survived for a maximum of three to four months at a relative humidity of 58, and for only two to four months at 30 degrees C and humidities of 73 and 84. Exposed virus in the form of vesicle fluid in capillaries did not survive for three months at this temperature in any of these humidities.These results suggest that variola virus in scabs or seeds in tropical climates-i.e., at temperatures of from 30 degrees C to 40 degrees C or higher-is unlikely to survive for as long as six months. Thus, if the period of storage of cotton were at least six months after ginning and before shipment from cotton-producing countries in the tropics where smallpox is endemic, the chances of importation of viable variola virus on raw cotton into areas free from infection would be very small. However, if cotton can become contaminated with smallpox scabs in temperate climates (20 degrees -25 degrees C) or is already contaminated when imported at this temperature, the experiments indicate that a few particles of virus may survive for as long as 18 months. The virus can, of course, survive for many years, ten or more, at from 4 degrees C to 5 degrees C in closed tubes or bottles, with little decrease in titre.

Cotton Fiber↗
PubMed2007

The bacterial profile of cotton lint from worldwide origins, and links with occupational lung disease.

BACKGROUND: Byssinosis, the cotton worker's lung disease persists today in many countries. Several agents have been investigated with respect to causality; among these are Gram-negative bacteria. These organisms are a source of lipopolysaccharide toxins, which are potentially hazardous to the respiratory tract. Despite byssinosis being most prevalent in countries where adequate preventive procedures are lacking, the majority of past studies have been conducted on cotton from the United States. METHODS: The current investigation, involved the identification of Gram-negative bacteria from cotton lint samples originating in 12 world regions. RESULTS: The current investigation, involved the identification of Gram-negative bacteria from cotton lint samples originating in 12 world regions. CONCLUSIONS: Building a bacterial profile of cotton samples with worldwide origins will be useful in isolating sources of these organisms, assessing the risk posed to industry, workers and ultimately assisting the prevention of byssinosis and related conditions.

Africa↗
PubMed2003

Human neutrophil elastase inhibition with a novel cotton-alginate wound dressing formulation.

Occlusion and elasticity were combined in a novel cotton-based alginate dressing containing a nontoxic elastase inhibitor. Cotton gauzes were modified with a textile finishing process for incorporating alginate to yield a dressing material that retains elasticity while enhancing absorption. The algino-cellulose conjugates were formed through citric acid crosslinking of cellulose and alginate. The alginate-citrate finishes were applied to cotton gauzes in various formulations containing citric acid, sodium hypophosphite, and polyethylene glycol. The modified gauzes contain a citrate conjugate of alginate and cellulose that gels upon hydration. The alginate-citrate finishes were combined with the neutrophil elastase inhibitor, oleic acid, to demonstrate the ability of the algino-cellulose fibers to release the inhibitor and neutralize destructively high levels of neutrophil elastase found in nonhealing and burn wounds. Four types of gauzes were examined for the effect of the algino-cellulose finish on cotton gauze absorbency and elasticity. Fourier transform infrared (FTIR) spectroscopy of the film and alginate-citrate finished cotton showed formation of the alginate and citrate cellulose esters. Scanning electron microscopy analysis revealed large areas of the yarn surface covered by the alginate film with a smooth surface on the original fibers. Wetting of the gauze surface resulted in formation of a hydrated gel on the yarns with apparent swelling of the film and the fiber-coated alginate.

Alginates↗
PubMed2003

Cotton fiber germin-like protein. I. Molecular cloning and gene expression.

The presence of cotton ( Gossypium hirsutum L.) fiber transcripts coding for a germin-like protein (GLP) was revealed by differential display analysis in which early stages of cotton fiber development between a wild type line, Texas Marker-1 (TM1) and a near isogenic mutant, Naked Seed (N1) were compared. Transcripts of the cotton GLP ( GhGLP1) accumulated specifically in TM1, but did not accumulate in the mutant although the GhGLP1 gene was present in both lines. The deduced protein sequence of GhGLP1 is similar to Prunus persica auxin-binding proteins, a barley ADP-glucose pyrophosphatase/phosphodiesterase and two different classes of hydrogen peroxide-producing enzymes: wheat germin oxalate oxidase and moss extracellular Mn-superoxide dismutase. Cotton GLPs constitute a multigene family like those of Arabidopsis, rice, soybean, and barley. GhGLP1 transcripts accumulated to their highest levels during the period of fiber expansion, followed by a sharp decline when the rate of cell expansion decreased. While germins and GLPs appear to be involved in defense mechanisms in some plants, both biotic and abiotic stress down-regulated the expression of GhGLP1. Numerous functions have been proposed for dicot GLPs. However, to date, there is little direct evidence for how these proteins function in vivo. The association of maximal GhGLP1 expression with stages of maximal cotton fiber elongation suggests that some GLPs may be important for cell wall expansion.

Amino Acid Sequence↗
PubMed2006

Characterization of bioscoured cotton fabrics using FT-IR ATR spectroscopy and microscopy techniques.

The effects of bioscouring were investigated by characterizing the chemical and physical surface changes of cotton fabrics using a purified pectinase enzyme from Bacillus subtilis strain WSHB04-02. Fourier-transform infrared (FT-IR) attenuated total-reflectance (ATR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques were employed. FT-IR ATR spectroscopy provided a fast and semi-quantitative assessment of the removal of pectins and/or waxes on the cotton surface by comparing the changes in intensity of the carbonyl peak induced by HCl vapor treatment at around 1736 cm(-1). The bioscoured surface could be clearly distinguished from those of untreated and alkali-treated cotton fibers using a combination of SEM and AFM. The images produced using these techniques revealed that the surface morphography and topography of the cotton fibers were shaped by the etching action mode of pectinases during bioscouring. These findings demonstrated that AFM is a useful supplement to SEM in characterizing cotton surfaces.

Bacillus subtilis↗
PubMed2002

Use of inverse gas chromatography to characterize cotton fabrics and their interactions with fragrance molecules at controlled relative humidity.

The present work focused on the surface characterization and fragrance interactions of a common cotton towel at different relative humidities (RHs) using inverse gas chromatography (IGC) and dynamic vapour sorption. The sigmoidal water sorption isotherms showed a maximum of 16% (w/w) water uptake with limited swelling at 100% RH. This means that water interacts strongly with cotton and might change its initial physico-chemical properties. The same cotton towel was then packed in a glass column and characterized by IGC at different relative humidities, calculating the dispersive and specific surface energy components. The dispersive component of the surface energy decreases slightly as a function of relative humidity (42 mJ/m2 at 0% RH to 36 mJ/m2 at 80% RH) which would be expected from swelling of the humidified cotton. The Gutmann's donor constant Kd increased from 0.28 kJ/mol at 0% RH to 0.42 kJ/mol at 80% RH, indicating that a greater hydrophilic surface exists at 80% RH, which is also as expected. Water, undecane and four fragrance molecules (dimetol, benzyl acetate, decanal and phenylethanol) were used to investigate cotton-fragrance interactions between 0 and 80% RH. The adsorption enthalpies and the Henry's constants were calculated and are discussed. The higher values for the adsorption enthalpies of polar molecules such as dimetol and phenylethanol suggest the presence of hydrogen bonds as the main adsorption mechanism. The Henry's constant of dimetol was also determined by headspace gas chromatography measurements at 20% RH, giving a similar value (230 nmol/Pa g by IGC and 130 nmol/Pa g by headspace GC), supporting the usefulness of IGC for such determinations. This work confirms the usefulness of chromatographic methods to investigate biopolymers such as textiles, starches and hairs.

Chromatography, Gas↗
PubMed2005

Cloning and functional characterization of two cDNAs encoding NADPH-dependent 3-ketoacyl-CoA reductased from developing cotton fibers.

Genes encoding enzymes involved in biosynthesis of very long chain fatty acids were significantly up-regulated during early cotton fiber development. Two cDNAs, GhKCR1 and GhKCR2 encoding putative cotton 3-ketoacyl-CoA reductases that catalyze the second step in fatty acid elongation, were isolated from developing cotton fibers. GhKCR1 and 2 contain open reading frames of 963 bp and 924 bp encoding proteins of 320 and 307 amino acid residues, respectively. Quantatitive RT-PCR analysis showed that both these genes were highly preferentially expressed during the cotton fiber elongation period with much lower levels recovered from roots, stems and leaves. GhKCR1 and 2 showed 30%-32% identity to Saccharomyces cerevisiae Ybr159p at the deduced amino acid level. These cotton cDNAs were cloned and expressed in yeast haploid ybr159wD mutant that was deficient in 3-ketoacyl-CoA reductase activity. Wild-type growth rate was restored in ybr159wD cells that expressed either GhKCR1 or 2. Further analysis showed that GhKCR1 and 2 were co-sedimented within the membranous pellet fraction after high-speed centrifugation, similar to the yeast endoplasmic reticulum marker ScKar2p. Both GhKCR(s) showed NADPH-dependent 3-ketoacyl-CoA reductase activity in an in vitro assay system using palmitoyl-CoA and malonyl-CoA as substrates. Our results suggest that GhKCR1 and 2 are functional orthologues of ScYbr159p.

3-Hydroxyacyl CoA Dehydrogenases↗