Showing papers by "Mississippi State University published in 1992"
TL;DR: It is shown that if insects can move from plant to plant, seed mixtures may actually hasten insect resistance compared with pure stands of toxic plants, suggesting potential problems with a third strategy, tissue-specific expression of toxins, which essentially provides a mixture of toxin-free and toxin-containing tissues on the same plant.
Abstract: Transgenic crops expressing insecticidal toxins could soon provide safe, clean and effective means of pest control, but their usefulness will be short-lived if insects adapt to the toxins. Two planting strategies are among those that have been recommended to delay crop failure: susceptible insects could be conserved by planting either ‘refugia’, i.e. separate fields of toxic and toxin-free crop, or ‘seed mixtures’ of toxic and toxin-free plants in the same fields. However, we show that if insects can move from plant to plant, seed mixtures may actually hasten insect resistance compared with pure stands of toxic plants. Insect movement causes an increase in effective genetic dominance which can counteract reduced selection due to the mixture. This failure of seed mixtures is likely under just those conditions, low genetic dominance of resistance, which predict a good chance for resistance to the toxin to evolve slowly. Seed mixtures, unlike refugia, are therefore failure prone. This result also suggests potential problems with a third strategy, tissue-specific expression of toxins, which essentially provides a mixture of toxin-free and toxin-containing tissues on the same plant. However, better information and modelling are urgently required to evaluate alternative means of slowing insect adaptation to resistant crop plants. Legislation for toxinfree refugia may provide one of the best available means for conserving insect susceptibility.
284 citations
TL;DR: In this article, the potential entrepreneur evaluates whether there are positive expected net present benefits of entrepreneur-sharing with the potential worker, and evaluates whether or not there are negative expected net benefits of entrepreneurship.
Abstract: The decision to become an entrepreneur is considered as an alternative to wage labor. The potential entrepreneur evaluates whether there are positive expected net present benefits of entrepreneursh...
248 citations
TL;DR: Results indicate that β-1,3 glucan potentially could be utilized prophylactically as an immunomodulator in channel catfish.
Abstract: . Intraperitoncal injection of β-l,3 glucan in channel catfish, Ictalurus punctatus Rafinesque, greatly reduces mortality from experimental infection with Edwardsiella ictaluri. Anterior kidney phagocytes from fish receiving glucan had enhanced phagocytic and bactericidal ability. The elevated bactericidal ability of phagocytes was not accompanied by increased production of hydrogen peroxide. Fish injected with glucan responded to subsequent E. ictaluri immunizations with higher serum antibody titres relative to the control catfish. The timing of glucan administration and antigen immunization was also important. These results indicate that β-1,3 glucan potentially could be utilized prophylactically as an immunomodulator in channel catfish.
231 citations
TL;DR: Number of bolls produced, bolls retained, and percent retention were progressively reduced as time per day at 40°C was increased, and Cultivars appeared to be similar in sensitivity to high temperature.
Abstract: Temperature is a major environmental factor that affects cotton (Gossypium hirsutum L.) production. Temperatures of 35 to 40°C are frequently observed in cotton-producing areas. High-temperature environments are sometimes associated with cotton sterility and boll retention problems; however, there is little specific information available on cotton sensitivity to temperature. We conducted a series of experiments in naturally lit growth chambers where the temperature was accurately controlled so we could measure its effects on cotton fruiting site production, abscission of flower buds (squares), flowers, and bolls. Cotton plants grown from seedlings at 40°C for 12 h d⁻¹ shed all their squares. Plants grown from seedlings in the natural environment, then exposed to daytime temperatures of 30,35, or 40°C during the fruiting period accumulated 47, 5.7, and <1%, respectively, of their mass as bolls. The time of day when plants were exposed to high temperature did not influence percent boll retention. Number of bolls produced, bolls retained, and percent retention were progressively reduced as time per day at 40°C was increased. Three week exposure to 40°C for 2 or 12 h d⁻¹ resulted in 64 or 0% bolls, respectively, retained on the plants. Cultivars appeared to be similar in sensitivity to high temperature. Cultivars tolerant to short periods of high temperature would probably be more productive in today's environment and increased tolerance to high temperature will be even more essential in a warmer environment. Contribution from Dep. of Agronomy, and the USDA-ARS Crop Simulation Res. Unit, Crop Sci. Res. Lab., Mississippi State Univ.
177 citations
TL;DR: Differences among fish species in type, cellular distribution, and function of granulocytes are the focus of this review, as evidenced by the increasing number of reports in scientific literature.
137 citations
01 Jan 1992
134 citations
TL;DR: Developmental rates, as depicted by number of mainstem nodes produced, number of fruiting branches, and fruiting branch nodes, were not as sensitive to temperatures above 30/22°C as were growth rates, and less time was required for this cultivar to produce squares at any temperature, suitable for growing cotton, than was suggested by previous experiments.
Abstract: Temperature is a primary environmental factor controlling growth and developmental rates of plants, yet little specific information is available regarding cotton (Gossypium hirsutum L.) responses to temperature. Information covering a wide range of temperatures would be useful for predicting both developmental and growth rates in cotton. Therefore, an experiment was conducted in naturally lit, temperature- and CO₂-controlled cabinets from soon after emergence until 56 d after emergence (DAE). The cabinets were maintained at 20/12, 25/17,30/22,35/27, and 40/32°C day/night cycles. Plant heights, number of nodes, and leaf areas were determined weekly throughout the experiment, and dry weight measurements were obtained at three intervals. Mainstem elongation, leaf area growth, and biomass accumulation rates were very sensitive to temperature about 3 wk after emergence. Prior to that time, they were relatively insensitive to temperature. The temperature optimum for stem elongation, leaf area expansion, and biomass accumulation was 30/22°C. Developmental rates, as depicted by number of mainstem nodes produced, number of fruiting branches, and fruiting branch nodes, were not as sensitive to temperatures above 30/22°C as were growth rates. Four times as many fruiting branches were produced at 30/22°C as at 20/12°C; whereas more vegetative branches were produced at low temperatures. All flower buds (squares) abscised from plants grown at 40/32°C. Essentially, all bolls and squares were retained at 30/22 °C while a 10% boll and square loss was observed at 35/27 °C during the early reproductive period. Less time was required for this cultivar to produce squares at any temperature, suitable for growing cotton, than was suggested by previous experiments. Contribution from Mississippi State Dep. of Agronomy as paper J7641, and the USDA-ARS Crop Simulation research Unit, Crop Sci. Res. Lab., Mississippi State, MS.
127 citations
TL;DR: There is a need for caution in extrapolating from rodent studies regarding the role of reactive nitrogen intermediates in anti-tumor or anti-microbial functions of human macrophages, because of the heterogeneity among macrophage populations.
120 citations
TL;DR: In this article, a study of loblolly pine in central Louisiana under mild soilwater deficit lasted for 252 days, one-third of which was used in the formation of early-wood.
102 citations
TL;DR: In this paper, a longitudinal panel study, including a control community, provides data on disruption and stress experienced by res idents of a small fishing community in Prince William Sound, Alaska, revealing a continuing pattern of stress and disruptions.
Abstract: The study of technological disasters has been characterized by conceptual am biguity and non-ecological considerations of community vulnerability. This re search employs an ecological-symbolic theoretical approach that identifies nat ural resource communities as particularly vulnerable to disasters that contaminate biophysical resources. A longitudinal panel study, including a control community, provides data on disruption and stress experienced by res idents of a small fishing community in Prince William Sound, Alaska. The analysis reveals a continuing pattern of stress and disruptions some 18 months following the spill. The report concludes with a discussion of the specific long- term patterns observed.
101 citations
TL;DR: Proton and 13C chemical shift assignments are reported for the neuropeptide Met‐enkephalin (ME) in both aqueous solution and in the presence of 50 mM sodium dodecyl sulfate (SDS).
Abstract: Proton and 13C chemical shift assignments are reported for the neuropeptide Met-enkephalin (ME) in both aqueous solution and in the presence of 50 mM sodium dodecyl sulfate (SDS). Rotating frame nuclear Overhauser enhancement spectroscopy was used to qualitatively describe interproton distances. These distances were then used as restraints in the distance geometry based molecular modeling program Dspace, developed by Hare Research to generate sets of conformations of ME. The resulting aqueous solution conformations of ME were determined to exhibit characteristic of an extended random-coil polypeptide with no distinguishable secondary structure. The resulting set of solution conformations of ME in the presence of 50 m M SDS exhibited characteristics of an amphiphilic type IV β turn that are stabilized by hydrophobic aromatic-aromatic interactions between the side chains of Tyr1 and Phe4. © 1992 John Wiley & Sons, Inc.
TL;DR: Using an interview and questionnaire format, driving under the influence of alcohol (DUI) first offenders and multiple offenders were compared on measures of personality traits, drinking behavior and problems, and driving behavior and history and indicated that multiple offenderswere significantly higher in hostility, sensation seeking, psychopathic deviance, mania, and depression.
TL;DR: Mainstem elongation rates were very sensitive to temperature after about 3 wk following emergence, and growth and developmental rates of Pima cotton plants grown at different temperatures were verysensitive to temperature.
Abstract: (...) The objective of this experiment was to determine the growth and developmental rates of Pima cotton plants grown at different temperatures. Pima cotton was grown in 20/12, 25/17, 30/22, 35/27, and 40/32°C day/night temperature cycles in sunlit controlled-environment chambers soon after emergence to 64 d under optimum water and nutrient conditions. Plant heights and mainstem nodes were determined at weekly intervals. Mainstem elongation rates were very sensitive to temperature after about 3 wk following emergence (...)
TL;DR: Results suggest that dietary fat has its greatest effect on growth after 10 days of age, and initiation of growth may be more closely dependent upon other nutrients.
TL;DR: Experiments were conducted to study the effect on broiler performance of grinding corn with different hammer mill screen openings (HMSO) and body weights were reduced when corn was ground through 9.59- and 3.18-mm HMSO for the starter and finisher diets, respectively.
Abstract: Intimacy is a topic of importance with respect to many aspects of relationship theory and a variety of academic disciplines. A consideration of the literature reveals much research but little consensus on even such basic issues as a definition of intimacy. Given that, a phenomenological study was done to determine what ordinary people meant by, and experienced as, intimacy. Results of that study revealed seven major components to intimate experiences. These included: non-verbal communication, presence, time, boundary, body, destiny/surprise and transformation. The relationship between these results and previous research is discussed.
28 Jun 1992
TL;DR: An approach to identifying conjuncts of coordinate conjunctions appearing in text which has been labelled with syntactic and semantic tags is presented and it performs relatively well on a large real-life domain.
Abstract: This paper presents an approach to identifying conjuncts of coordinate conjunctions appearing in text which has been labelled with syntactic and semantic tags. The overall project of which this research is a part is also briefly discussed. The program was tested on a 10,000 word chapter of the Merck Veterinary Manual. The algorithm is deterministic and domain independent and it performs relatively well on a large real-life domain. Constructs not handled by the simple algorithm are also described in some detail.
TL;DR: The influence of sugar esters of various hydrophilic-lipophilic balances on the textural properties of nonfat low-calorie yogurts was assessed over 14-d storage at 4°C as discussed by the authors.
TL;DR: Canine distemper was diagnosed in 78% of the foxes, was geographically widespread, was detected in 16 of 18 yr, and exhibited a seasonal pattern of occurrence, indicating that canine distemmer is more significant as a mortality factor for gray foxes than all other infectious and noninfectious diseases combined.
Abstract: Diagnostic findings were reviewed on 157 sick or dead gray foxes (Urocyon cinereoar-genteus) from the southeastern United States examined during the period 1972 through 1989. Most foxes (n = 118) originated from Georgia; fewer animals were from Florida, Kentucky, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia and West Virginia. Etiologic diagnoses included canine distemper (n = 125), congenital absence of guard hairs (n = 7), traumatic injuries (n = 7), rabies (n = 3), suspected toxicoses (n = 3), verminous pneumonia due to Paragonimus kellicotti (n = 1), bacterial septicemia secondary to Dracunculus insignis (n = 1), and tick paralysis (n = 1). Concurrent toxoplasmosis or cryptosporidiosis was noted in six and three foxes with canine distemper, respectively. Only lesion diagnoses were attainable for three foxes, and six cases were classified as undetermined. Canine distemper was diagnosed in 78% of the foxes, was geographically widespread, was detected in 16 of 18 yr, and exhi...
Journal Article•
TL;DR: Results indicate that suppression of humoral responses by morphine is not primarily mediated by direct action of morphine on the immune system.
Abstract: Morphine suppresses humoral immune responses, causes thymic hypoplasia and suppresses NK (natural killer) activity in animal models. There is evidence that thymic hypoplasia and NK suppression are predominantly mediated by indirect mechanisms. The mechanism of morphine-induced humoral immunosuppression is less certain. Recent reports suggest that morphine and other opioids can directly act on cells of the immune system to suppress the generation of antibody-forming cells (AFC) in Mishell-Dutton cultures. The present study was designed to assess the roles of direct and indirect mechanisms in morphine-induced suppression of humoral immunity. Splenocytes from mice treated with morphine by s.c. implantation of a slow-release 75 mg pellet were dysfunctional in Mishell-Dutton cultures. Exposure to morphine in vivo for 12 or 24 hr caused significant suppression of the AFC production stimulated by sheep erythrocytes in Mishell-Dutton cultures. In contrast, direct addition of morphine or the kappa selective opioid agonist U50,488H to Mishell-Dutton cultures under a variety of conditions had little or no effect on AFC generation. These results indicate that suppression of humoral responses by morphine is not primarily mediated by direct action of morphine on the immune system. Suppression of AFC responses by administration of morphine in vivo was substantially blocked by treating mice with the glucocorticoid antagonist RU 38486, suggesting that glucocorticoids may be involved in the indirect mechanism by which morphine causes splenocyte dysfunction.
TL;DR: The IM-Rhozyme-41 gave up to a 3.2-fold increase in the emulsifying activity, whereas emulsion stability was improved using IM-trypsin this article.
TL;DR: Dose-response curves constructed from EAGs of females revealed a low threshold for (Z)-3-hexenyl acetate, a compound previously shown to be an effective attractant in wind-tunnel bioassays.
Abstract: Antennal olfactory responses of the parasitoid,Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), to 29 cotton volatile compounds were measured by electroantennogram (EAG) techniques. No significant sexual differences were found in EAGs of males and females to volatiles emanating from 100-μg stimulus loads of the 29 cotton compounds. Green leaf volatiles (saturated and monounsaturated six-carbon alcohols, aldehydes, and their acetate derivatives), heptanal, and the benzene derivatives, benzaldehyde and acetophenone, elicited the largest EAGs. Monoterpenes elicited moderate EAGs withβ-ocimene being the most effective monoterpene tested. Among the sesquiterpenes tested,β-bisabolol was the most effective stimulus at the 100-μg dose. Dose-response curves constructed from EAGs of females revealed a low threshold for (Z)-3-hexenyl acetate, a compound previously shown to be an effective attractant in wind-tunnel bioassays. Comparison of relative volatilities of the various odorants indicated differential selectivity and sensitivity ofM. croceipes antennal receptors to them. The roles of cotton plant volatiles in host habitat location ofM. croceipes are discussed.
TL;DR: The analysis provides evidence against the hypothesis that the gundi (an African rodent) represents the most ancient rodent lineage and indicates that myomorph and caviomorph genes evolve, on average, about two times faster than their human counterparts.
Abstract: On the basis of 18 protein sequences totaling 2,413 aligned amino acid sites, it is suggested that the guinea pigs and the myomorphs (rat-like rodents) are not monophyletic. Rather, the evolutionary lineage leading to the guinea pig seems to have branched off prior to the divergence among myomorphs, lagomorphs, primates, chiropterans, artiodactyls, and carnivores. It is suggested therefore that the Caviomorpha (guinea pig-like rodents) and possibly the Hystricomorpha (porcupine-like rodents) should be elevated in taxonomic rank and conferred an ordinal status distinct from the Rodentia. This suggestion calls for a reevaluation of the morphological evolution of guinea pigs and further molecular studies on the possibility of paraphyly of the order Rodentia. If the monophyly of rodents holds, it must be concluded that the pattern of molecular evolution in many guinea pig genes has been extremely unusual and that the causes for this pattern should be sought. It is also suggested that claims of large differences in the rate of molecular evolution between guinea pigs and myomorphs may have been exaggerated in many cases as a result of an erroneous phylogenetic position for the guinea pig. The average rate of amino acid replacement in the guinea pig seems to be comparable to that in the rat and the mouse. However, the data indicate that myomorph and caviomorph genes evolve, on average, about two times faster than their human counterparts. Finally, our analysis provides evidence against the hypothesis that the gundi (an African rodent) represents the most ancient rodent lineage.
TL;DR: The polymerase chain reaction (PCR) technique was applied to the detection of infectious bursal disease virus (IBDV) and no PCR product was detected from genomic nucleic acids of turkey hemorrhagic enteritis virus, infectious bronchitisirus, reovirus, Salmonella enteritidis, Escherichia coli, and uninfected bursae.
Abstract: The polymerase chain reaction (PCR) technique was applied to the detection of infectious bursal disease virus (IBDV). Reverse transcription followed by the PCR was used to amplify a portion of IBDV genome. A set of primers that specify a 150-base-pair segment of IBDV genome was chosen from an Australian strain of IBDV. Standard challenge strain and variant strains A, D, E, G, and GLS-5 of IBDV serotype 1 and OH strain of serotype 2 from infected bursae were subjected to reverse transcription, followed by 30 cycles of PCR. A single band of the PCR product (DNA) of the expected size from each strain of IBDV was visible on polyacrylamide gels stained with ethidium bromide. Using the same primers, no PCR product was detected from genomic nucleic acids of turkey hemorrhagic enteritis virus, infectious bronchitis virus, reovirus, Salmonella enteritidis, Escherichia coli, and uninfected bursae. The PCR could be efficiently performed on serially diluted IBDV RNA and could detect 2 femtograms of IBDV RNA. The identity of the PCR products was confirmed by direct sequencing. The PCR is a specific and sensitive method for the detection of IBDV.
TL;DR: High pressure liquid chromatography data showed that the gossypol content of susceptible and resistant glanded lines is equal, whereas three other terpenoid aldehydes, hemigossypolione and heliocides H1 and H2, are greatly increased in resistant lines, and they are presumably more closely associated with resistance.
Abstract: Female moths of the tobacco budworm, Heliothis virescens (F.), oviposit in terminals of the cotton plant, Gossypium hirsutum (L.). The hatched larvae feed in the terminal area, then migrate to small squares (buds) where they feed and finally burrow into and feed on the anthers, where they grow rapidly. They attempt to avoid feeding on gossypol glands during the first 48 h after hatching. When tobacco bud worm neonate larvae were fed squares of highly glanded lines, growth was decreased by 25–75%. The number of glands in calyx and bract tissues of squares of resistant lines was significantly higher than in susceptible lines. The difference was greatest in the calyx crown where the ratio in resistant to susceptible lines was 10–20 fold. The calyx crown of highly glanded resistant lines also was high in terpenoid aldehydes. High pressure liquid chromatography data showed that the gossypol content of susceptible and resistant glanded lines is equal, whereas three other terpenoid aldehydes, hemigossypolone and heliocides H1 and H2, are greatly increased in resistant lines, and they are presumably more closely associated with resistance.
TL;DR: In fact, evidence from Nicaragua and El Salvador indicates that substantial numbers of women from humble backgrounds have participated in those nations' guerrilla armies, and not simply in support roles but also in combat roles.
Abstract: Evidence from Nicaragua and El Salvador indicates that substantial numbers of women from humble backgrounds have participated in those nations' guerrilla armies, and not simply in support roles but...
TL;DR: In vitro brush-border transport of three monosaccharides by pig intestine was studied as a function of postnatal age from immediately after birth before suckling to after weaning, suggesting transporter development is partly genetically hard-wired, apparently to prepare pigs for weaning.
Abstract: In vitro brush-border transport of three monosaccharides by pig intestine was studied as a function of postnatal age from immediately after birth before suckling to after weaning. Rates of transport normalized to tissue weight or surface area for glucose (Glc), galactose (Gal), and fructose (Fru) were highest at birth, with a steep decline after the onset of suckling, probably caused by any combination of three or more factors: reduced transporter site density, shifts in relative abundances of different monosaccharide transporters, and/or changes in activities of individual transporters. Whereas highest rates of Glc and Fru transport shifted from proximal to midintestine after weaning, Gal transport remained highest in proximal intestine. Postnatal increases in Km values for Gal, but not Glc, indicate there are multiple aldohexose transporters that undergo separate developmental trajectories. The presence of Fru transport in neonatal pigs may reflect a more advanced state of development than neonatal rats and rabbits, or may be an adaptation for early weaning. Changes in Fru-to-Glc and Gal-to-Glc transport ratios before weaning suggest transporter development is partly genetically hard-wired, apparently to prepare pigs for weaning. Curiously, Fru-to-Glc transport ratios were lower than those of rat and rabbit, but closely paralleled those of the carnivorous cat.
TL;DR: It was found that juvenile channel catfish do have a potassium requirement that can be met by either dietary potassium or the uptake of potassium from the rearing water, similar to the dietary potassium requirement of the rat, chick and young pig.
TL;DR: Remote sensing of highly turbid finfish aquaculture impoundments using the Calibrated Airborne Multispectral Scanner (CAMS) mounted on a Lear jet flown at 900 m was conducted in central Mississippi, finding no model to effectively estimate c‐phycocyanin concentrations.
Abstract: Remote sensing of highly turbid finfish aquaculture impoundments using the Calibrated Airborne Multispectral Scanner (CAMS) mounted on a Lear jet flown at 900 m was conducted in central Mississippi on 16 May 1990. Concurrent in situ data consisted of phytoplankton pigment concentrations and standing crop, water color, turbidity, and surface-water temperature. Surface and near-surface assemblages of cyanophytes and chlorophytes varied dramatically among impoundments; total chlorophyll concentrations and standing crop values ranged from 8 to 483 mg·m−3 and 8.0 × 102 to 2.2 × 106 cells-mL−1, respectively. Regression models fit to CAMS data provided reliable estimates for and produced accurate digital cartographs of total chlorophyll and carotenoid concentrations, phytoplankton standing crop, and turbidity. Although a model to effectively estimate in situ c-phycocyanin concentrations was not identified, the lack of a suitable model may have resulted from variability of pigment extraction during quantification rather than failure of remotely sensed imagery to detect c-phycocyanin. Models derived from imagery of impoundments directly beneath the aircraft sufficiently described in situ parameters in imagery of adjacent series of impoundments not directly below the aircraft. High-resolution airborne remote sensing provides a means for monitoring local phytoplankton dynamics in temporal and spatial scales analogous to biotic and abiotic processes affecting such dynamics and necessary for applications to ecological research and fisheries or aquacultural management.
TL;DR: The previously proposed hypothesis thatwhite-rot extracellular enzymes oxidatively degrade stilbenes which makes white-rot fungi immune to stilBenes may need to be reexamined.