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Respiratory symptoms and dust exposure in Lancashire cotton and man-made fiber mill operatives.

A cross-sectional study of work-related symptoms and cotton dust exposure was made in 404 man-made fiber and 1,048 cotton operatives in Lancashire spinning mills; 39 cotton-exposed operatives (3.7%) had symptoms of byssinosis. This was associated on regression analysis with cumulative lifetime cotton dust exposure (p < 0.001), total years spent carding (p < 0.001), and currently working in the carding area (p = 0.0041). Smoking habit did not differ significantly between byssinotic and nonbyssinotic workers. Other work-related symptoms were common: chronic bronchitis (CB) and persistent cough. The prevalence of CB correlated positively with dust exposure (r = 0.59). Cotton dust sampling was performed in the work area (SDPRES) and personal breathing zone (PD1). A retrospective estimate of lifetime cotton dust exposure based on SDPRES correlated best with the prevalence of byssinosis (r = 0.797), although correlations with PD1 (r = 0.709) and SDPRES (r = 0.594) were also significant.

Adult↗

Genomic heterozygosity and hybrid breakdown in cotton (Gossypium): different traits, different effects.

BACKGROUND: Hybrid breakdown has been well documented in various species. Relationships between genomic heterozygosity and traits-fitness have been extensively explored especially in the natural populations. But correlations between genomic heterozygosity and vegetative and reproductive traits in cotton interspecific populations have not been studied. In the current study, two reciprocal F2 populations were developed using Gossypium hirsutum cv. Emian 22 and G. barbadense acc. 3-79 as parents to study hybrid breakdown in cotton. A total of 125 simple sequence repeat (SSR) markers were used to genotype the two F2 interspecific populations. RESULTS: To guarantee mutual independence among the genotyped markers, the 125 SSR markers were checked by the linkage disequilibrium analysis. To our knowledge, this is a novel approach to evaluate the individual genomic heterozygosity. After marker checking, 83 common loci were used to assess the extent of genomic heterozygosity. Hybrid breakdown was found extensively in the two interspecific F2 populations particularly on the reproductive traits because of the infertility and the bare seeds. And then, the relationships between the genomic heterozygosity and the vegetative reproductive traits were investigated. The only relationships between hybrid breakdown and heterozygosity were observed in the (Emian22 &#xd7; 3-79) F2 population for seed index (SI) and boll number per plant (BN). The maternal cytoplasmic environment may have a significant effect on genomic heterozygosity and on correlations between heterozygosity and reproductive traits. CONCLUSIONS: A novel approach was used to evaluate genomic heterozygosity in cotton; and hybrid breakdown was observed in reproductive traits in cotton. These findings may offer new insight into hybrid breakdown in allotetraploid cotton interspecific hybrids, and may be useful for the development of interspecific hybrids for cotton genetic improvement.

Chromosomes, Plant↗

Complete nucleotide sequence of the cotton (Gossypium barbadense L.) chloroplast genome with a comparative analysis of sequences among 9 dicot plants.

Recently, the complete chloroplast genome sequences of many important crop plants were determined, and this can be considered a major step forward toward exploiting the usefulness of chloroplast genetic engineering technology. Economically, cotton is one of the most important crop plants for many countries. To further our understanding of this important crop, we determined the complete nucleotide sequence of the chloroplast genome from cotton (Gossypium barbadense L.). The chloroplast genome of cotton is 160,317 base pairs (bp) in length, and is composed of a large single copy (LSC) of 88,841 bp, a small single copy (SSC) of 20,294 bp, and two identical inverted repeat (IR) regions of 25,591 bp each. The genome contains 114 unique genes, of which 17 genes are duplicated in the IRs. In addition, many open reading frames (ORFs) and hypothetical chloroplast reading frames (ycfs) with unknown functions were deduced. Compared to the chloroplast genomes from 8 other dicot plants, the cotton chloroplast genome showed a high degree of similarity of the overall structure, gene organization, and gene content. Furthermore, the sequences of the genes showed high degrees of identity at the DNA and amino acid levels. The cotton chloroplast genome was somewhat longer than the chloroplast genomes of most of the other dicot plants compared here. However, this elongation of the cotton chloroplast genome was found to be due mainly to expansions of the intergenic regions and introns (non-coding DNA). Moreover, these expansions occurred predominantly in the LSC and SSC regions.

Base Sequence↗

Microscopical comparison of cotton, corn, and soybean dusts.

Specialized analytical methods are required for identification of components of agricultural dusts such as those generated in harvesting, transportation, storage, and processing of cotton, corn, and soybeans. The larger particles and trash components of the dusts can often be identified visually or with the aid of an optical microscope (OM). The respirable portion of the dust, that which causes lung dysfunction, retains few structural features for identification. Electron microscopy and X-ray microanalysis, together with special optical microscopical techniques, can be used to characterize these microdusts. Combination studies with scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis of cotton dusts have shown the presence of mineralogical particles probably of a soil origin and materials that can be associated with plant parts. Even in screened and filtered cotton dusts, fibrillar fragments are usually present due to their ability to penetrate openings the size of their diameters. The corn and soybean dusts studied were different from the cotton dust in that the large fibrillar component of the cotton dust was absent in the screened grain dusts. However, these dusts consisted of structurally unrecognizable particles that appeared similar to those found in cotton dust. In addition they contained many spheroid particles identified as starch. Dusts from all three sources were found to agglomerate into larger particles, some of which were still less than 10 micron. This agglomeration could confuse the instrumental measurement of dust particle size.

Dust↗

Cotton dust concentrations and particle size distributions associated with genotypes.

The problem of byssinosis has plagued cotton textile mills for hundreds of years, and it is still a problem today. With the regulations on airborne raw cotton dust set by OSHA and the ACGIH, research regarding the measurement of cotton dust in lint fiber is a necessity. A procedure known as the mass concentration particle size distribution (MCPSD) technique, developed at Texas A&M University, was used to measure the characteristics of cotton dust as affected by harvesting method and genotype. Cotton genotypes from three harvest seasons were analyzed by using a Coulter Counter, Model TAII, to obtain the mass concentrations and particle size distributions of dust present in the lint fiber. The genotypes were subjected to both hand harvesting and conventional spindle harvesting for comparison purposes. Results from the dust concentration analyses of particles less than 100 micron, 16 micron, and 8 micron in diameter, respectively, are presented. Also, a proposed procedure to obtain large quantities of "cotton dust" from gin trash material is discussed.

Byssinosis↗

In vitro release of arachidonic acid and in vivo responses to respirable fractions of cotton dust.

It was considered that the fall in lung function seen after exposure to cotton dust may be attributable in part to the activity of arachidonic acid metabolites, such as leucotrienes as well as to the more established release of histamine by cotton dust. However, we found that cotton and barley dusts elicited poor release of arachidonic acid from an established macrophage like cell line compared with that observed with other organic dusts. In the experimental animal, pulmonary cellular responses to both cotton and barley dust were similar to those evoked by moldy hay and pigeon dropping dusts, although after multiple doses a more severe response was seen to cotton and barley. Since both moldy hay and pigeon droppings elicit a greater arachidonic acid release than cotton or barley, a role for arachidonic acid in inducing the cellular response is less likely than other factors. There are limitations to our conclusions using this system, i.e., the arachidonic acid may be released in a nonmetabolized form, although it is noted that the two dusts with the greatest arachidonic acid release produce their clinical responses in humans largely by hypersensitivity mechanisms.

Animals↗

Cotton dust and complement in vivo.

Cotton grown in Stoneville, Mississippi and harvested by three different methods was examined for anticomplementary activity in human serum in vivo. Subjects exposed to cotton dust in a model cardroom for six hours showed changes in C3c and CH50 after exposure to closed boll harvested, bract removed cotton dust when compared with a group of normal, unexposed controls. Decreases in C3c, :C4, and C3A were associated with decreases in FEV1 after exposure to closed boll harvested bract intact cotton dust. The data from this preliminary study suggest in vivo associations between inhalation of cotton dusts and complement which appear to be independent of endotoxin contamination. These findings suggest a relationship between cotton dust inhalation and complement-mediated respiratory impairment.

Adolescent↗

Efficacy of insecticides of different chemistries against Helicoverpa zea (Lepidoptera: Noctuidae) in transgenic Bacillus thuringiensis and conventional cotton.

Six insecticides of different chemistries were evaluated against the cotton bollworm, Helicoverpa zea (Boddie), in non-B.t. (Deltapine 'DP 5415', Deltapine 'DP 5415RR') and transgenic Bacillus thuringiensis (Berliner) (B.t.) (Deltapine 'NuCOTN 33B', Deltapine 'DP 458 B/RR') cotton. In 1998, treatments consisted of three rates each of a pyrethroid (lambda-cyhalothrin), spinosyn (spinosad), carbamate (thiodicarb), pyrrole (chlorfenapyr), oxadiazine (indoxacarb), and avermectin (emamectin benzoate) in a nonirrigated field. In 1999, treatments consisted of three rates each of lambda-cyhalothrin, spinosad, thiodicarb, and indoxacarb in an irrigated and a nonirrigated (dryland) field. The highest rate of each insecticide corresponded to normal grower-use rates. Spinosad and thiodicarb controlled H. zea in non-B.t. cotton, whereas other materials were less effective. Even though H. zea is becoming increasingly resistant to pyrethroid insecticides, lambda-cyhalothrin was highly effective in dryland B. thuringiensis cotton. Spinosad and thiodicarb were equally effective. Data indicated that reduced rates of lambda-cyhalothrin, spinosad, and thiodicarb could be used for control of H. zea in dryland B.t. cotton systems. However, reduced rates of these insecticides in a heavily irrigated B.t. cotton system did not provide adequate control.

Animals↗

Response of cotton to prebloom square loss.

In 1996 and 1997, various intensities of prebloom square removal were applied to three cultivars of cotton grown in Mississippi. With the exception of one cultivar in 1997, all cultivars were B. thuringiensis (Bt)-transgenic cotton. At harvest, the number of bolls and seed cotton weight was recorded for all plants in each square removal treatment. All cultivars responded similarly to square loss. A yield increase (overcompensation) was observed in the treatment where all squares were removed from the plant one week after squaring began. Only the treatment where all squares were removed before bloom significantly reduced yield and caused a large (>7 d) delay in crop maturation. Otherwise, moderate levels of square removal (approximately 20-50% of prebloom squares) had little impact on overall lint production. However, the patterns of cotton production on the plants were significantly influenced by the square removal treatments. The removal of relatively more or larger squares increased seed cotton production in late-season fruiting cohorts and on 'vegetative' branches. Compensation for square loss occurred by increasing the relative number and weight of bolls produced subsequent to early-season square removal. Typically, early-season square loss increased the value of later-season fruiting cohorts, especially the midseason cohorts and bolls on vegetative branches. The implications of prebloom square loss, including the compensatory ability of the cotton plant, on insect management are discussed.

Animals↗

Bollworm (Lepidoptera: Noctuidae) survival on 'Bollgard' and 'Bollgard II' cotton flower bud and flower components.

Genetically modified cotton, Gossypium hirsutum L., cultivars ('Bollgard') that produce crystalline proteins from Bacillus thuringiensis (Berliner) are valuable tools for managing lepidopteran insect pests in the United States. However, high numbers of bollworm, Helicoverpa zea (Boddie), larvae have been observed feeding in white flowers of these cultivars. Fresh tissue bioassays were conducted to investigate bollworm survival on Bollgard and 'Bollgard II' cottons. Bollworm survival was higher on square and flower anthers than on other floral structures on 'Deltapine 5415' (conventional cotton) and 'NuCOTN 33B' (Bollgard). Bollworm survival at 72 h was higher on all floral structures from Deltapine 5415 than on corresponding structures from NuCOTN 33B. ELISA tests indicated that CryIA(c) expression varied among plant parts; however, bollworm survival did not correlate with protein expression levels. Trends in bollworm survival on Bollgard II were similar to those on Bollgard and conventional cotton; however, survival was lower on all structures of Bollgard II than on corresponding structures of Bollgard and conventional cotton. These data support field observations of bollworm injury to white flowers and small bolls and provide a better understanding of larval behavior on Bollgard cotton.

Animals↗

Behavior of bollworm (Lepidoptera: Noctuidae) larvae on genetically engineered cotton.

Reports of bollworm, Helicoverpa zea (Boddie), larvae feeding in white flowers of Bollgard cotton have been relatively common since the commercialization of this technology in 1996. Field studies were conducted in Louisiana to determine if differences in bollworm larval behavior occuron non-Bollgard (cultivar 'Deltapine 5415') and Bacillus thuringiensis (Bt), Bollgard ('NuCOTN 33B') cottons. Larvae were placed on the terminal foliage of either single cotton plants or on all plants within 1-m row micro-plots. On preflowering cotton plants, significantly more bollworms moved from the site of infestation (terminal) on Bollgard plants compared with that on non-Bollgard plants. On individual flowering plants, the number of nodes larvae moved from the terminal and the number of infested bolls was greater on Bollgard cotton plants. Similar differences between Bollgard and non-Bollgard plants in the percentage of infested terminals and squares were observed at 48-h after infestation when 1-m rows were infested. These data will be used to refine scouting protocols for bollworm larvae on Bollgard cotton.

Animals↗

Association between resistance to Bt cotton and cadherin genotype in pink bollworm.

Two strains of pink bollworm, Pectinophora gossypiella (Saunders), each derived in 1997 from a different field population, were selected for resistance to Bacillus thuringiensis (Bt) toxin Cry1Ac in the laboratory. One strain (MOV97-R) originated from Mohave Valley in western Arizona; the other strain (SAF97-R) was from Safford in eastern Arizona. Relative to a susceptible laboratory strain, Cry1Ac resistance ratios were 1700 for MOV97-R and 520 for SAF97-R. For the two resistant strains, larval survival did not differ between non-Bt cotton and transgenic cotton producing CrylAc. In contrast, larval survival on Bt cotton was 0% for the two unselected parent strains from which the resistant strains were derived. Previously identified resistance (r) alleles of a cadherin gene (BtR) occurred in both resistant strains: r1 and r3 in MOV97-R, and r1 and r2 in SAF97-R. The frequency of individuals carrying two r alleles (rr) was 1.0 in the two resistant strains and 0.02 in each of the two unselected parent strains. Furthermore, in two hybrid strains with a mixture of susceptible (s) and r alleles at the BtR locus, all survivors on Bt cotton had two r alleles. The results show that resistance to Cry1Ac-producing Bt cotton is associated with recessive r alleles at the BtR locus in the strains of pink bollworm tested here. In conjunction with previous results from two other Bt-resistant strains of pink bollworm (APHIS-98R and AZP-R), results reported here identify the cadherin locus as the leading candidate for molecular monitoring of pink bollworm resistance to Bt cotton.

Animals↗

Spontaneous enterochromaffin-like cell carcinomas in cotton rats (Sigmodon hispidus) are prevented by a somatostatin analogue.

Among inbred female cotton rats (Sigmodon hispidus) 25-50% of the animals develop spontaneous gastric carcinomas; the corresponding figure for male cotton rats is approximately 1%. Animals with carcinomas have hypergastrinaemia and gastric hypo-anacidity and the tumours are derived from enterochromaffin-like (ECL) cells. The mechanism behind the hypo-anacidity is unknown. Carcinomas are found in all female cotton rats with hypergastrinaemia lasting more than 4 months and this represents an excellent animal model for studying gastric carcinogenesis. In this study, the somatostatin analogue octreotide was given to female cotton rats to prevent carcinoma development caused by hypergastrinaemia. Twelve female cotton rats were given monthly injections of long-acting octreotide (5 mg i.m.) for 6 months. A control group of 20 animals was not given injections. Of the 20 control animals, 13 developed hypergastrinaemia and histologically invasive carcinomas or dysplasia. Of the 12 animals in the octreotide group, five developed hypergastrinaemia. None of these five animals developed histological cancer (P<0.05), whereas three had dysplasia. However, octreotide did not affect plasma gastrin concentration or antral gastrin mRNA abundance significantly. Dysplasia of the oxyntic mucosa in hypergastrinaemic animals was accompanied by a marked increase in chromogranin A-immunoreactive cells and cells positive for Sevier-Munger staining. The malignant tissue also contained groups of cells with Sevier-Munger staining. In conclusion, octreotide prevented ECL cell carcinomas in hypergastrinaemic cotton rats without lowering the gastrin concentration.

Animals↗

A prospective study of chronic lung disease in cotton textile workers.

A cohort of both active and retired older cotton textile workers was examined prospectively over a 6-year period to establish the nature and extent of chronic lung disease. Respiratory symptoms and lung function were studied in these workers and in a group of similarly aged controls. The cotton textile workers had higher prevalence and attack rates of respiratory symptoms than did controls even with smoking habits taken into account. Chronic bronchitis developed in 16% of all cotton textile workers compared to 1% of controls over the follow-up period (p less than 0.001). The cotton workers suffered a larger loss of lung function over 6 years than did controls. Male workers lost 42 mL/yr of forced expiratory volume in 1 second, although male controls lost only 25 mL/yr (p = 0.001). Similar differences were seen in women, and in both men and women who were nonsmokers. Retired cotton textile workers had more symptoms and disability than active workers. We conclude that chronic lung disease is not only irreversible but may progress even after exposure to cotton dust has ended.

Byssinosis↗

Experimental infection of cotton rats with three naturally occurring Bartonella species.

The kinetics of infection and humoral immune response of laboratory-bred cotton rats (Sigmodon hispidus) challenged with three Bartonella spp. recovered from the blood of naturally infected cotton rats captured in Georgia (USA) are described. Bartonella spp. infection, as determined by bacteremia, occurred in all 18 cotton rats inoculated with live Bartonella of each species at either a low dose, 10(3) colony-forming units (CFU's), or high dose, 10(7) CFU. Cotton rats inoculated with lower doses of Bartonella spp. developed higher bacteremia that persisted for longer periods than in those inoculated with high doses. Peak bacteremia varied among Bartonella spp, ranging from 10(4) to 10(6) CFUs per 1.0 ml of blood. Antibody measured by immunofluorescence assays using species-specific antigens indicated more rapidly rising and higher antibody titers in cotton rats challenged with high doses vs. low doses and with inactivated bacteria vs. live bacteria. Each group of rats produced high IgG titers to the homologous challenge antigen; low or unmeasurable cross-reactivity was detected to heterologous Bartonella antigens. Exposure of cotton rats to a specific Bartonella sp. resulted in protection, as measured by detectable bacteremia, in eight of nine animals challenged with the same Bartonella sp. used initially; no evidence of resistance to secondary challenge with different Bartonella spp. was obtained. Cross-protection between Bartonella spp., isolated from the same rodent species, may not occur.

Animals↗

Fluorosis risks to resident hispid cotton rats on land-treatment facilities for petrochemical wastes.

Land-treatment of petroleum wastes is a widely used industrial practice, yet there has been no comprehensive evaluation of the long-term risks to human or terrestrial ecosystems from such practices. We evaluated cotton rat (Sigmodon hispidus) populations on three sites in Oklahoma (USA) that historically used land-treatment for disposal of various petroleum wastes (July 1995-March 1997). Average concentrations of fluoride in soil from these sites ranged from 878 to 4317 mg/kg. A census of resident cotton rats on land-treatment sites revealed a high incidence (40% overall) of dental lesions compared to reference populations (<1% dental lesions). During winter there was a 34% to 65% increase compared to summer in frequency of dental lesions in cotton rats on two of the three land-treatment sites. Incidence of dental lesions on two land-treatment sites was greater (9-16%) in female cotton rats compared to males. Cotton rats from land-treatment sites had higher concentrations of fluoride in bone and greater severity of dental lesions compared to reference animals. Dental lesions were considered to be most consistent with dental fluorosis because of elevated fluoride in bone. Neither concentration of fluoride in soil nor level of fluoride in bone was a good predictor of severity of dental lesions in cotton rats on land-treatment sites.

Animals↗

[Determination of benzidine in cotton cloth by high performance liquid chromatography(HPLC)].

In this paper, a method for determination of benzidine in cotton cloth by HPLC was studied. First, cotton cloth was treated by sodium dithionite at the temperature of (70 +/- 2) degrees C. On this condition, azo dyes in cotton cloth were reduced to benzidine. Then benzidine was extracted by diethyl ether in sodium hydroxide solution. Benzidine originating from cotton cloth was analysed by HPLC with a column of Hypersil ODS (5 microns, 15 cm x 4.6 mm i.d.), mobile phase of V (MeOH):V(H2O) = 75:25, flow rate of 0.6 mL/min, pressure of 17.7 MPa and detection at 254 nm. By comparison with the standard sample, the retention time of benzidine was about 2.5 min. Benzidine in three samples was determined through parallel experiment. The mass ratio of benzidine in cotton cloth was 94.01, 86.9 and 120.8 micrograms/g, and the average was 100.57 micrograms/g. The average recovery was 84.7%. The experiment expressed that benzidine originating from cotton cloth could be qualitatively and quantitatively determined by HPLC. The accuracy of the results of parallel experiments was related to the reducing process. When the reducing conditions were completely consistent, the result would be more accurate.

English Abstract↗

[Photosynthetic characters and Bt toxin content of different transgenic Bt cottons].

The study on the photosynthetic characters and Bt toxin content of different Bt cottons (ZK, GK) and non-Bt cotton (CZ) indicated that Bt cottons GK and ZK had different total expressed amount of Bt toxin and its distribution in different tissues. The Bt cottons had obviously different chlorophyll contents, responses of photosynthetic rate to photosynthetic active radiation, and diurnal changes of photosynthetic rate and transpiration rate, but the diurnal change of leaf temperature, CO2 concentration inside leaf cells and stomatal limit values were approximately the same. There was a significant difference between two transgenic Bt cottons in the diurnal average value of CO2 concentration inside leaf cells, but the differences in other characteristics were not significant among different cottons.

Bacillus thuringiensis Toxins↗