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Sample records for alligator weed alternanthera

  1. The evolutionary history of an invasive species: alligator weed, Alternanthera philoxeroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The eco-evolutionary mechanisms of biological invasions are still not thoroughly understood. Alligator weed, Alternanthera philoxeroides (Martius) Gisebach (Amaranthaceae), is a plant native to South America and a weed in Australia and other countries. To better understand its success as an invader,...

  2. Cadmium and lead residues in field-collected red swamp crayfish (Procambarus clarkii) and uptake by alligator weed, Alternanthera philoxiroides

    SciTech Connect

    Naqvi, S.M.; Howell, R.D.; Sholas, M. . Dept. of Biological Sciences and Health Research Center)

    1993-01-01

    The whole-body residues of Cd and Pb in the tissues of Louisiana swamp crayfish (Procambarus clarkii) were determined by flame AAS technique. Test animals were collected from roadside ditches alongside major highways. The water and soil samples were also collected from the same sites. The mean Cd and Pb concentrations in crayfish tissues were 0.46 and 0.07, respectively. The levels of Cd and Pb in the water were 0.09 and 0.04; and in soil were 2.85 and 0.87 mg/1, respectively. The concentration of cadmium was 32 and Pb 12 times more than in the water. The bioaccumulation factors (BF) for Cd and Pb in crayfish tissues were 5.1 and 1.7, respectively. Alligator weed (Alternanthera philoxiroides) plants were exposed to 0.5 mg/1 Cd-chloride or Pb-nitrate solutions for 3 wk period, thrice. The mean Pb accumulation in roots was 1.31 mg/1, followed by stem (0.078 mg/1), but Cd only accumulated in root (0.83 mg/1). The BF for Pb and Cd in plant tissues were 14.8 and 16.6, respectively. The uptake of metals was time-dependent. These data suggest that although there is no biomagnification of Cd and Pb from alligator weed to crayfish, both metals readily accumulate in field-collected crayfish and laboratory-exposed alligator weed.

  3. Cytogenetic effect of Alternanthera philoxeroides (alligator weed) on Agasicles hygrophila (Coleoptera: Chrysomelidae) in its native range

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant polyploidy potentially affects plant-insect interactions; however, its effect on insect fitness remains largely unexplored. Alternanthera philoxeroides is a South American amphibious Amaranthaceae, which invades aquatic and terrestrial habitats. Different morphotypes and cytotypes were identif...

  4. Phenrica littoralis a potential candidate for the biological control of alligator weed, Alternanthera philoxeroides: redscription of the adult, first description of immature stages and biological notes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flea beetles of aliligator weed, Alternanthera philoxeroides (Martius) Grisebach (Amaranthaceae), were collected in Argentina, Uruguay, Paraguay and Brazil. Species in the genera Disonycha Chevrolat, Agasicles Jacoby Systena Chevrolat and Phenrica Bechyne were frequently found on this weed. Phenric...

  5. Bio-gas production from alligator weeds

    NASA Technical Reports Server (NTRS)

    Latif, A.

    1976-01-01

    Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanthera philoxeroides. Efforts were also made for the isolation and characterization of the methanogenic bacteria.

  6. Alternathera philoxeroides (Martius) Grisebach - alligator weed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological control of Alternanthera philoxeroides, alligator weed, began when George Vogt, USDA, conducted several surveys by public transport in South America during the 1960s. Three agents were released in USA and two of them, the flea beetle Agasicles hygrophila and the moth Arcola malloi were re...

  7. Water Hyacinths and Alligator Weeds for Final Filtration of Sewage

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

    1976-01-01

    The potential of water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxerides) (Mart.) Griesb. as secondary and tertiary filtration systems for domestic sewage was demonstrated. These two vascular aquatic plants reduced the suspended solids, total Kjeldahl nitrogen, total phosphorus, BOD sub 5, and total organic carbon levels in domestic sewage from 60 percent to 98 percent within a two week period. These plants grown in domestic sewage were also free of toxic levels of trace heavy metals.

  8. Water hyacinths and alligator weeds for removal of lead and mercury from polluted waters

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Removal of lead and mercury by water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb. was investigated. Water hyacinths demonstrated the ability to remove 0.176 mg of lead and 0.150 mg of mercury per gram of dry plant material from distilled water and river water in a 24-hour period. One acre of water hyacinths is potentially capable of removing 105.6 grams of lead and 90.0 grams of mercury per day. Alligator weeds removed 0.101 mg of lead per gram of dry plant material in a 24-hour period. This same plant also demonstrated the ability to remove a minimum of 0.153 mg of mercury per gram of dry plant material in a six hour period.

  9. Environmental risk assessment of compost prepared from salvinia, egeria densa, and alligator weed.

    PubMed

    Dorahy, C G; Pirie, A D; McMaster, I; Muirhead, L; Pengelly, P; Chan, K Y; Jackson, M; Barchia, I M

    2009-01-01

    Approximately 70,000 m(3) of salvinia (Salvinia molesta) was removed from the Hawkesbury-Nepean River, New South Wales (NSW), Australia, during 2004. This study assessed the risks associated with applying compost prepared from aquatic weeds (AWC) to land, namely, survival and spread of aquatic and terrestrial weeds, eutrophication of waterways, accumulation of heavy metals and phytotoxicity. The results demonstrate composting is an effective method of reducing the viability of aquatic and terrestrial weeds. However, mortality of alligator weed (Alternanthera philoxeroides), which was used as an indicator plant, was significantly (P < 0.001) correlated with the temperature within the windrows and the length of time the material was subjected to composting. Conditions within the central core of the windrow were sufficient to kill the alligator weed, although not all of the aquatic weed material was exposed to the windrows' central core. This resulted in alligator weed continuing to grow at the base of the windrow. To reduce the risk of weeds surviving and spreading in aquatic and terrestrial environments it is suggested compost windrows should be located on an appropriate hard pad to enable complete mixing of the material and ensure all material is exposed to temperatures >55 degrees C for greater than three consecutive days. The likelihood of other risks associated with the AWC was low. If composting is selected as the preferred method for managing organic material harvested from waterways, then ongoing monitoring and evaluation is required to validate the composting process and ensure consumer confidence in the final product. PMID:19465724

  10. Invertebrate community composition differs between invasive herb alligator weed and native sedges

    NASA Astrophysics Data System (ADS)

    Bassett, Imogen E.; Paynter, Quentin; Beggs, Jacqueline R.

    2012-05-01

    Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator weed) and native sedges (Isolepis prolifer and Schoenoplectus tabernaemontani) in a New Zealand lake. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Lower invertebrate abundance, richness and proportionally fewer specialists were predicted on A. philoxeroides compared to native sedges, but with greatest differences between A. philoxeroides and S. tabernaemontani. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Invertebrate abundance showed taxa-specific responses, rather than consistently lower abundance on A. philoxeroides. Nevertheless, as predicted, invertebrate fauna of A. philoxeroides was more similar to that of I. prolifer than to S. tabernaemontani. The prediction of a depauperate native fauna on A. philoxeroides received support from some but not all taxa. All vegetation types hosted generalist-dominated invertebrate communities with simple guild structures. The enemy release hypothesis thus had minimal ability to predict patterns in this system. Results suggest the extent of architectural and chemical differences between native and invasive vegetation may be useful in predicting the extent to which they will host different invertebrate communities. However, invertebrate ecology also affects whether invertebrate taxa respond positively or negatively to weed invasion. Thus, exotic vegetation may support distinct invertebrate communities despite similar overall invertebrate abundance to native vegetation.

  11. Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

  12. “Patterns of morphological variation of alligator weed (Alternanthera philoxeroides): from native to invasive regions”

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The damage caused by biological invasions has traditionally been thought to result from alien species taking advantage of ecological differences between the native and introduced regions. In contrast, evidence is increasing that invasive plants can undergo rapid adaptive evolution during the process...

  13. "Patterns of morphological variation of alligator weed (Alternanthera philoxeroides): from native to invasive regions"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The damage caused by biological invasions has traditionally been thought to result from alien species taking advantage of ecological differences between the native and introduced regions. In contrast, evidence is increasing that invasive plants can undergo rapid adaptive evolution during the process...

  14. Biosorption of As(V) onto dried alligator weed root: role of metal (hydro) oxides.

    PubMed

    Chen, Jian; Tao, Weihua; Sun, Cheng

    2016-01-01

    The present work investigates the adsorption of As(V) onto the dried powder of alligator weed root as bio-sorbent, using acid pre-treated alligator weed root powder as the reference. The isotherm study suggested there is a favorable As(V) adsorption happened on the AWR surface. The batch adsorption experimental results indicated that the ionic strength has little impact on the adsorption, while the solution pH has a significant effect on the adsorption with apparent inhibition appearing in both extreme acidic and alkaline pH region. In addition, the properties of the biosorbent were characterized by various techniques including SEM-EDS, FT-IR, and ICP detection. The analysis results suggested that the metals including Mn, Fe, and Al enrich over the alligator weed root surface in the morphology of metal (hydro) oxide. Based on the nature of the biosorbent and As(V) besides the adsorption performance, the metal (hydro) oxides over biosorbent surface is suggested as the essential role to drive the adsorption. With the metal (hydro) oxides denuded in the pre-treatment, the biosorbent loses its adsorption capability for As(V) totally. PMID:26458188

  15. Phenotypic plasticity of invasive Alternanthera philoxeroides in relation to different water availability, compared to its native congener

    NASA Astrophysics Data System (ADS)

    Geng, Yu-Peng; Pan, Xiao-Yun; Xu, Cheng-Yuan; Zhang, Wen-Ju; Li, Bo; Chen, Jia-Kuan

    2006-11-01

    Phenotypic plasticity and genetic differentiation are two possible mechanisms that plants use to cope with varying environments. Although alligator weed ( Alternanthera philoxeroides) possesses very low genetic diversity, this alien weed has successfully invaded diverse habitats with considerably varying water availability (from swamps to dry lands) in China. In contrast, its native congener ( Alternanthera sessilis) has a much narrower ecological breadth, and is usually found in moist habitats. To understand the mechanisms underlying the contrasting pattern, we performed a greenhouse experiment to compare the reaction norms of alligator weed with those of its native congener, in which water availability was manipulated. Our results revealed that the two congeners had similar direction of phenotypic plasticity. However, A. philoxeroides showed greater plasticity in amount than did A. sessilis in many traits examined during the switch from wet to drought treatment. Nearly all of the phenotypic variance in A. philoxeroides could be ascribed to plasticity, while A. sessilis had a much higher fraction of phenotypic variance that could be explained by genotypic variation. These interspecific differences in plastic responses to variable water availability partially explained the difference in spatial distribution of the two congeners.

  16. Salinity effects on photosynthesis and growth in Alternanthera philoxeroides (Mart. ) Griseb

    SciTech Connect

    Longstreth, D.J.; Bolanos, J.A.; Smith, J.E.

    1984-08-01

    Alternanthera philoxeroides, alligator weed, was grown at five different NaCl concentrations to determine the effect of salinity on factors related to the net rate of CO/sub 2/ uptake (P/sub n/). Over the range of 0 to 400 millimolar NaCl, P/sub n/ declined 51%. Stomatal conductance declined in parallel with P/sub n/ and as a result there was no reduction in intercellular CO/sub 2/ concentrations and therefore no reduction in the amount of CO/sub 2/ available for photosynthesis. The CO/sub 2/ compensation point did not change with salt stress. Increases in leaf thickness tended to compensate slightly for the negative effects of salinity on leaf cell metabolism, at least in relation to P/sub n/. On a mesophyll cell area basis, soluble protein was relatively constant in leaves developed at 100 to 400 millimolar NaCl while total chlorophyll decreased at all salinities. Dry weight production and P/sub n/ were closely correlated in alligator weed grown at different salinities. Plants produced less leaf area per unit dry weight as salinity increased, which may aid in water conservation. 26 references, 5 figures, 2 tables.

  17. Salinity Effects on Photosynthesis and Growth in Alternanthera philoxeroides (Mart.) Griseb. 1

    PubMed Central

    Longstreth, David J.; Bolaños, Jorge A.; Smith, James E.

    1984-01-01

    Alternanthera philoxeroides, alligator weed, was grown at five different NaCl concentrations to determine the effect of salinity on factors related to the net rate of CO2 uptake (Pn). Over the range of 0 to 400 millimolar NaCl, Pn declined 51%. Stomatal conductance declined in parallel with Pn and as a result there was no reduction in intercellular CO2 concentration and therefore no reduction in the amount of CO2 available for photosynthesis. The CO2 compensation point did not change with salt stress. Increases in leaf thickness tended to compensate slightly for the negative effects of salinity on leaf cell metabolism, at least in relation to Pn. On a mesophyll cell area basis, soluble protein was relatively constant in leaves developed at 100 to 400 millimolar NaCl while total chlorophyll decreased at all salinities. Dry weight production and Pn were closely correlated in alligator weed grown at different salinities. Plants produced less leaf area per unit dry weight as salinity increased, which may aid in water conservation. PMID:16663731

  18. Salinity Effects on Water Potential Components and Bulk Elastic Modulus of Alternanthera philoxeroides (Mart.) Griseb. 1

    PubMed Central

    Bolaños, Jorge A.; Longstreth, David J.

    1984-01-01

    Pressure volume curves for Alternanthera philoxeroides (Mart.) Griseb. (alligator weed) grown in 0 to 400 millimolar NaCl were used to determine water potential (Ψ), osmotic potential (ψs), turgor potential (ψp) and the bulk elastic modulus (ε) of shoots at different tissue water contents. Values of ψs decreased with increasing salinity and tissue Ψ was always lower than rhizosphere Ψ. The relationship between ψp and tissue water content changed because ε increased with salinity. As a result, salt-stressed plants had larger ranges of positive turgor but smaller ranges of tissue water content over which ψp was positive. To our knowledge, this is the first report of such a salinity effect on ε in higher plants. These increases in ε with salinity provided a mechanism by which a large difference between plant Ψ and rhizosphere Ψ, the driving force for water uptake, could be produced with relatively little water loss by the plant. A time-course study of response after salinization to 400 millimolar NaCl showed Ψ was constant within 1 day, ψs and ψp continued to change for 2 to 4 days, and ε continued to change for 4 to 12 days. Changes in ε modified the capacity of alligator weed to maintain a positive water balance and consideration of such changes in other species of higher plants should improve our understanding of salt stress. PMID:16663611

  19. Phenotypic variation and water selection potential in the stem structure of invasive alligator weed

    NASA Astrophysics Data System (ADS)

    Du, Leshan; Yang, Beifen; Guan, Wenbin; Li, Junmin

    2016-02-01

    The morphological and anatomical characteristics of stems have been found to be related to drought resistance in plants. Testing the phenotypic selection of water availability on stem anatomical traits would be useful for exploring the evolutionary potential of the stem in response to water availability. To test the phenotypic variation of the stem anatomical traits of an invasive plant in response to water availability, we collected a total of 320 individuals of Alternanthera philoxeroides from 16 populations from terrestrial and aquatic habitats in 8 plots in China and then analyzed the variation, differentiation, plasticity and selection potential of water availability on the stem anatomical traits. We found that except for the thickness of the cortex, all of the examined phenotypic parameters of the A. philoxeroides stem were significantly and positively correlated with soil water availability. The phenotypic differentiation coefficient for all of the anatomical structural parameters indicated that most of the variation existed between habitats within the same plot, whereas there was little variation among plots or among individuals within the same habitat except for variation in the thickness of the cortex. A significant phenotypic plasticity response to water availability was found for all of the anatomical traits of A. philoxeroides stem except for the thickness of the cortex. The associations between fitness and some of the anatomical traits, such as the stem diameter, the cortex area-to-stem area ratio, the pith cavity area-to-stem area ratio and the density of vascular bundles, differed with heterogeneous water availability. In both the aquatic and terrestrial habitats, no significant directional selection gradient was found for the stem diameter, the cortex area-to-stem area ratio or the density of vascular bundles. These results indicated that the anatomical structure of the A. philoxeroides stem may play an important role in the adaptation to changes

  20. Salinity effects on water potential components and bulk elastic modulus of Alternanthera philoxeroides (Mart. ) Griseb

    SciTech Connect

    Bolanos, J.A.; Longstreth, D.J.

    1984-06-01

    Pressure volume curves for Alternanthera philoxeroides (Mart.) Grixeb. (alligator weed) grown in 0 to 400 millimolar NaCl were used to determine water potential (PSI), osmotic potential (psi/sub s/), turgor potential (psi/sub p/) and the bulk elastic modulus (element of) of shoots at different tissue water contents. Values of psi decreased with increasing salinity and tissue PSI was always lower than rhizosphere PSI. The relationship between psi/sub p/ and tissue water content changed because element of increased with salinity. As a results, salt-stressed plants had larger ranges of positive turgor but smaller ranges of tissue water content over which psi/sub p/ was positive. To our knowledge, this is the first report of such a salinity effect on element of in higher plants. These increases in element of with salinity provided a mechanism by which a large difference between plant PSI and rhizosphere PSI, the driving force for water uptake, could be produced with relatively little water loss by the plant. A time-course study of response after salinization to 400 millimolar NaCl showed PSI was constant with 1 day, psi/sub s/ and psi/sub p/ continued to change for 2 to 4 days, and element of continued to change for 4 to 12 days. Changes in element of modified the capacity of alligator weed to maintain a positive water balance and consideration of such changes in other species of higher plants should improve our understanding of salt stress. 24 references, 6 figures.

  1. The influence of abiotic stress and phenotypic plasticity on the distribution of invasive Alternanthera philoxeroides along a riparian zone

    NASA Astrophysics Data System (ADS)

    Pan, Xiaoyun; Geng, Yupeng; Zhang, Wenju; Li, Bo; Chen, Jiakuan

    2006-11-01

    Relatively few studies have compared invasibility and species invasiveness among microhabitats within communities, synchronously. We surveyed the abundance and performance of non-native Alternanthera philoxeroides (Mart.) Griseb. (alligator weed), its co-occurring native congener, Alternanthera sessilis (L.) DC. (sessile joyweed), and other species in a wetland community along a riparian zone in southeast China to test the hypotheses that: i) degree of invasion differs between different types of microhabitats within the community; and ii) microhabitat types that differ in invasibility also differ in soil resource availability or in sediment characteristics likely to affect resource availability; iii) phenotypic plasticity of A. philoxeroides may play a key role in its adaptation to diverse habitats as can be concluded from its extremely low genetic diversity in China. The study riparian zone comprises different types of microhabitats including wet abandoned field, swamp, marsh dunes and gravel dunes. Consistent with these hypotheses, cover of A. philoxeroides was high in abandoned fields (73 ± 2.9%) and swamps (94 ± 1.3%), which had high soil nutrients and water availability. On the contrary, cover of native A. sessilis was relatively high in marsh dunes and grave dunes, which had coarse gravel surfaces, low soil nutrients and low water availability. A. philoxeroides showed greater morphological plasticity in response to habitat variation. In abiotically harsh habitats, stems had limited growth, and were prostrate with weak adventitious roots at nodes, forming thin, scattered patches. In the two richer habitats, the highly branched plants spread over the water or soil surface, supporting dense stronger leaf-bearing stems which grew vertically. The growth pattern of A. sessilis among microhabitats did not exhibit significant variations. These results suggest that morphological plasticity and microhabitat types with high soil resources may facilitate invasions of A

  2. A literature review for the exotic invasive Alternanthera philoxeroides (alligatorweed)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this review, we present a detailed account of Alternanthera philoxeroides(alligatorweed), including A. philoxeroides description, intraspecific variation from native to introduced regions, its life history strategy, invasive mechanisms, and management strategy. Alternanthera philoxeroides is a he...

  3. Nonpineal melatonin in the alligator (Alligator mississippiensis).

    PubMed

    Roth, J J; Gern, W A; Roth, E C; Ralph, C L; Jacobson, E

    1980-10-31

    All living and most fossil representatives of the reptilian subclass Archosauria lack pineal bodies. Arrhythmic, low-level, nonpineal melatonin is present, however, in the blood of Alligator mississippiensis. Although pineal bodies have been implicated in circadian phenomena, these results suggest that arrhytmic melatonin in alligators may not be involved incircadian events and indicate that the pineal is not the only source of the hormone melatonin. The evolutionary loss of the pineal in Archosauria occurred during the Mesozoic, and era noted for its seasonal stability. Arrhythmic melatonin titers inalligators and pineal loss in alligators and other archosaurs may be related to Mesozoic seasonal stability. PMID:7423204

  4. Molecular phenotypes associated with anomalous stamen development in Alternanthera philoxeroides

    PubMed Central

    Zhu, Zhu; Zhou, Chengchuan; Yang, Ji

    2015-01-01

    Alternanthera philoxeroides is a perennial amphibious weed native to South America but has now spread to diverse parts of the world. A. philoxeroides reproduces both sexually and asexually in its native range, but propagates solely through vegetative means in its introduced range. Traits associated with sexual reproduction become degraded for sexual dysfunction, with flowers possessing either pistillate stamens or male-sterile anthers. Degradations of sexual characters for loss of sexuality commonly take place in clonal plants. The underlying molecular-genetic processes remain largely unknown. We compared the gene expression profiles of abnormal stamens with that of normal stamens by RNA-Seq analysis, and identified a large number of differentially expressed genes between abnormal and normal stamens. In accordance with flower morphology, the expression of B-class MADS-box genes (ApAP3, ApTM6, and ApPI) was markedly reduced in pistillate stamens. However, most of the genes involved in meiosis were expressed normally in stamens with male-sterile anthers. In addition to verifying the expression patterns of genes previously known to be related to stamen and pollen grain development, we also identified previously unknown molecular phenotypes associated with sexual dysfunction in A. philoxeroides, that is helpful for dissecting the molecular mechanisms underpinning various male-sterile phenotypes and the molecular processes underlying the transition from sexuality to asexuality in clonal plants. PMID:25926842

  5. A big alligator snacks on a smaller alligator

    NASA Technical Reports Server (NTRS)

    1998-01-01

    A large alligator attacks and eats a smaller one in a natural display of cannibalism. Although this event has been observed infrequently by Kennedy Space Center's staff photographers, it is common feeding behavior among the wild alligator population on the space center. Alligators are carnivorous and will eat any living thing that crosses their paths and is small enough for them to kill. For this reason, it is dangerous to feed wild alligators, and in Florida, it is also illegal. Kennedy Space Center is located on the Merritt Island National Wildlife Refuge which is operated by the U.S. Fish and Wildlife Service.

  6. Variability in alternanthera mosaic virus isolates from different hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have determined the complete genome sequences of Alternanthera mosaic virus phlox isolate PA (AltMV-PA) and four infectious clone variants derived from AltMV-SP, as well as partial sequences of other isolates from various types of phlox, and from portulaca, nandina, and cineraria. Phylogenetic co...

  7. The 'Angry Alligator'

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The Augmented Target Docking Adapter (ATDA) as seen from the Gemini 9 spacecraft during one of their three rendezvous in space. The ATDA and Gemini 9 spacecraft are 66.5 ft. apart. Failure of the docking adapter protective cover to fully separate on the ATDA prevented the docking of the two spacecraft. The ATDA was described by the Gemini 9 crew as an 'angry alligator.'

  8. WEED RESEARCH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds in peppermint and spearmint reduce mint oil yield and quality. Presence of weeds in mint hay at harvest can result in off flavors, odors, and colors in the oil. Several weed species have developed resistance to, or are poorly controlled by herbicides labeled for mint production. Pigweed is oft...

  9. Agronomic Weeds.

    ERIC Educational Resources Information Center

    Hartwig, Nathan L.

    This agriculture extension service publication from Pennsylvania State University examines agronomic weed problems and control. Contents include a listing of the characteristics of weeds, a section on herbicides, and a section on the important weeds of agronomic crops in Pennsylvania. The herbicide section discusses systemic herbicides, contact…

  10. Weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uncontrolled weeds in pepper can result in the total loss of the crop, or make harvest not economically feasible. Weed control is a major challenge in conventional and organic production systems. Agricultural weed control costs the U.S. economy more than the cost of insect and disease control comb...

  11. OOGENESIS AND OVARIAN HISTOLOGY OF THE AMERICAN ALLIGATOR ALLIGATOR MISSISSIPPIENSIS

    EPA Science Inventory

    Although folliculogenesis and oogenesis have been observed in numerous reptiles, these phenomena have not been described in detail in a crocodilian. Oogenesis and histological features of the adult ovary of Alligator mississippiensis are described. Using a complex process, the ov...

  12. Mercury in alligators (Alligator mississippiensis) in the southeastern United States

    USGS Publications Warehouse

    Jagoe, C.H.; Arnold-Hill, B.; Yanochko, G.M.; Winger, P.V.; Brisbin, I.L., Jr.

    1998-01-01

    Mercury methylation may be enhanced in wetlands and humic-rich, blackwater systems that crocodiles and alligators typically inhabit. Given their high trophic level and long life-spans, crocodilians could accumulate significant burdens of Hg. Our objectives were to survey Hg concentrations in alligators from several areas in the southeastern United States to test their utility as sentinels of Hg contamination, to examine relationships among Hg concentrations in various tissues and to look for any differences in tissue Hg concentrations among locations. We measured total Hg concentrations in alligators collected in the Florida Everglades (n = 18), the Okefenokee National Wildlife Refuge, Georgia (n = 9), the Savannah River Site (SRS), South Carolina (n = 49) and various locations in central Florida ( n = 21), sampling tissues including blood, brain, liver, kidney, muscle, bone, fat, spleen, claws and dermal scutes. Alligators from the Everglades were mostly juvenile, but Hg concentrations in tissues were high (means: liver 41.0, kidney 36.4, muscle 5.6 mg Hg/kg dry wt.). Concentrations in alligators from other locations in Florida were lower (means: liver 14.6, kidney 12.6, muscle 1.8 mg Hg/kg dry wt.), although they tended to be larger adults. Alligators from the Okefenokee were smallest and had the lowest Hg concentrations (means: liver 4.3, kidney 4.8, muscle 0.8 mg Hg/kg dry wt.). At some locations, alligator length was correlated with Hg concentrations in some internal organs. However, at three of the four locations, muscle Hg was not related to length. Tissue Hg concentrations were correlated at most locations; however, claw or dermal scute Hg explained less than 74% of the variation of Hg in muscle or organs, suggesting readily-obtained tissues, such as scutes or claws, have limited value for nondestructive screening of Hg in alligator populations.

  13. Essential fatty acid nutrition of the American alligator (Alligator mississippiensis).

    PubMed

    Staton, M A; Edwards, H M; Brisbin, I L; Joanen, T; McNease, L

    1990-07-01

    The essential fatty acid (EFA) nutrition of young American alligators (Alligator mississippiensis) was examined by feeding a variety of fats/oils with potential EFA activity. Over a 12-wk period, alligators fed diets containing 2.5 or 5.0% chicken liver oil grew longer and heavier and converted feed to body mass more efficiently than alligators fed other fat/oil combinations that lacked or contained only trace amounts of arachidonic acid [20:4(n-6)]. Alligators fed an EFA-deficient diet (containing only coconut fat as the dietary fat) were the slowest-growing animals and converted feed to body mass least efficiently. However, over a 41-wk feeding period, alligators fed this diet showed no obvious external signs of deficiency other than being reduced in size and unthrifty. Fatty acid composition of heart, liver, muscle, skin and adipose tissue lipids was influenced markedly by dietary fat composition. Tissues varied significantly in response to dietary fat composition. Heart lipids contained the lowest levels of short- and medium-chain fatty acids and the highest levels of arachidonic acid. Arachidonic acid levels were less influenced by diet than were levels of other 20- and 22-carbon polyunsaturated fatty acids. Radiotracer studies indicated that linoleic acid was converted to arachidonic acid in the liver. Nevertheless, tissue arachidonic acid levels also appeared to be maintained by concentration from dietary sources and selective conservation. It appears that a dietary source of arachidonic acid may be required for a maximum rate of growth. PMID:2114472

  14. Mortality of American alligators attributed to cannibalism

    USGS Publications Warehouse

    Delany, Michael F.; Woodward, Allan R.; Kiltie, Richard A.; Moore, Clinton T.

    2011-01-01

    Mortality of juvenile (Alligator mississippiensis) attributed to cannibalism on Orange Lake, Florida was examined. Alligator web tags used in mark–recapture studies were found in 12% of 267 stomachs sampled from alligators ≥168 cm TL. Captive alligators retained 76% of force-fed tags during a 588-d tag-retention trial. Models relating the probability of tag recovery to the annual probabilities of juvenile survival, cannibalism, tag retention, adult survival, and adult harvest suggested that cannibalism may on average remove 6–7% of the juvenile alligator population annually. Vulnerability continued to 140 cm TL (age 6–8 yr). Cannibalism of juveniles may serve to regulate the alligator population on Orange Lake. Alligator cannibalism may vary widely among populations, depending on demography and environmental conditions. The role and importance of cannibalism in alligator population dynamics should be more fully assessed and environmental and population factors that influence cannibalism identified to better evaluate management programs.

  15. Growth rates of Chinese and American alligators.

    PubMed

    Herbert, J D; Coulson, T D; Coulson, R A

    2002-04-01

    Growth rates in two closely related species, Alligator mississippiensis (American alligator) and Alligator sinensis (Chinese alligator), were compared under identical conditions for at least 1 year after hatching. When hatched, Chinese alligators were approximately 2/3 the length and approximately 1/2 the weight of American alligator hatchlings. At the end of 1 year of growth in captivity in heated chambers, the Chinese alligators were approximately 1/2 as long and weighed approximately 1/10 as much as American alligator yearlings. When the animals were maintained at 31 degrees C, Chinese alligator food consumption and length gain rates dropped to near zero during autumn and winter and body weights decreased slightly, apparently in response to the change in day length. At constant temperature (31 degrees C), food consumption by American alligators remained high throughout the year. Length gain rates in American alligators decreased slowly as size increased, but were not affected by photoperiod. Daily weight gains in American alligators increased steadily throughout the year. In autumn, provision of artificial light for 18 h a day initially stimulated both length and weight gain in Chinese alligators, but did not affect growth in American alligators. Continuation of the artificial light regimen seemed to cause deleterious effects in the Chinese alligators after several months, however, so that animals exposed to the normal light cycle caught up to and then surpassed the extra-light group in size. Even after removal of the artificial light, it was several months before these extra-light animals reverted to a normal growth pattern. These findings may be of interest to those institutions engaged in captive growth programs intended to provide animals for reintroduction to the wild or to protected habitat. PMID:11897202

  16. Alligator diet in relation to alligator mortality on Lake Griffin, FL

    USGS Publications Warehouse

    Rice, A.N.; Ross, J.P.; Woodward, A.R.; Carbonneau, D.A.; Percival, H.F.

    2007-01-01

    Alligator mississippiensis (American Alligators) demonstrated low hatch-rate success and increased adult mortality on Lake Griffin, FL, between 1998 and 2003. Dying Lake Griffin alligators with symptoms of poor motor coordination were reported to show specific neurological impairment and brain lesions. Similar lesions were documented in salmonines that consumed clupeids with high thiaminase levels. Therefore, we investigated the diet of Lake Griffin alligators and compared it with alligator diets from two lakes that exhibited relatively low levels of unexplained alligator mortality to see if consumption of Dorosoma cepedianum (gizzard shad) could be correlated with patterns of mortality. Shad in both lakes Griffin and Apopka had high levels of thiaminase and Lake Apopka alligators were consuming greater amounts of shad relative to Lake Griffin without showing mortality rates similar to Lake Griffin alligators. Therefore, a relationship between shad consumption alone and alligator mortality is not supported.

  17. Antibiotic oxylipins from Alternanthera brasiliana and its endophytic bacteria.

    PubMed

    Trapp, Marília Almeida; Kai, Marco; Mithöfer, Axel; Rodrigues-Filho, Edson

    2015-02-01

    Bioassay-guided fractionation of Alternanthera brasiliana stem extracts resulted in the isolation of an antibiotically active fraction. Five human pathogenic bacteria were used to guide the fractionation process for the isolation of antimicrobial compounds. Finally, 17 linoleate oxylipins were identified by LC-MS/MS and NMR spectroscopy. Five of the isolated compounds present in A. brasiliana tissues were also detected to be synthesized by endophytic bacteria of the genus Bacillus that were isolated from A. brasiliana. It is speculated that the antibiotic oxylipins from A. brasiliana might derive from bacteria and be involved in an ecological relationship between this plant and its endophytes. PMID:25433629

  18. AFFINITY OF THE ALLIGATOR ESTROGEN RECEPTOR FOR SERUM PESTICIDE CONTAMINANTS

    EPA Science Inventory

    Top predators, like the American alligator (Alligator mississippiensis) bioaccumulate and biomagnify persistent pollutants, such as organochlorine pesticides. In a recently published study, several pesticides and pesticide metabolites not previously reported in alligator eggs wer...

  19. Gene Expression Reaction Norms Unravel the Molecular and Cellular Processes Underpinning the Plastic Phenotypes of Alternanthera Philoxeroides in Contrasting Hydrological Conditions

    PubMed Central

    Gao, Lexuan; Geng, Yupeng; Yang, Hongxing; Hu, Yonghong; Yang, Ji

    2015-01-01

    Alternanthera philoxeroides is an amphibious invasive weed that can colonize both aquatic and terrestrial habitats. Individuals growing in different habitats exhibit extensive phenotypic variation but little genetic differentiation. Little is known about the molecular basis underlying environment-induced phenotypic changes. Variation in transcript abundance in A. philoxeroides was characterized throughout the time-courses of pond and upland treatments using RNA-Sequencing. Seven thousand eight hundred and five genes demonstrated variable expression in response to different treatments, forming 11 transcriptionally coordinated gene groups. Functional enrichment analysis of plastically expressed genes revealed pathway changes in hormone-mediated signaling, osmotic adjustment, cell wall remodeling, and programmed cell death, providing a mechanistic understanding of the biological processes underlying the phenotypic changes in A. philoxeroides. Both transcriptional modulation of environmentally sensitive loci and environmentally dependent control of regulatory loci influenced the plastic responses to the environment. Phenotypic responses and gene expression patterns to contrasting hydrological conditions were compared between A. philoxeroides and its alien congener Alternanthera pungens. The terricolous A. pungens displayed limited phenotypic plasticity to different treatments. It was postulated based on gene expression comparison that the interspecific variation in plasticity between A. philoxeroides and A. pungens was not due to environmentally-mediated changes in hormone levels but to variations in the type and relative abundance of different signal transducers and receptors expressed in the target tissue. PMID:26617628

  20. Classification of Weed Species Using Artificial Neural Networks Based on Color Leaf Texture Feature

    NASA Astrophysics Data System (ADS)

    Li, Zhichen; An, Qiu; Ji, Changying

    The potential impact of herbicide utilization compel people to use new method of weed control. Selective herbicide application is optimal method to reduce herbicide usage while maintain weed control. The key of selective herbicide is how to discriminate weed exactly. The HIS color co-occurrence method (CCM) texture analysis techniques was used to extract four texture parameters: Angular second moment (ASM), Entropy(E), Inertia quadrature (IQ), and Inverse difference moment or local homogeneity (IDM).The weed species selected for studying were Arthraxon hispidus, Digitaria sanguinalis, Petunia, Cyperus, Alternanthera Philoxeroides and Corchoropsis psilocarpa. The software of neuroshell2 was used for designing the structure of the neural network, training and test the data. It was found that the 8-40-1 artificial neural network provided the best classification performance and was capable of classification accuracies of 78%.

  1. Alligators in the Sewers? Really?

    ERIC Educational Resources Information Center

    Egbert, Joy

    2009-01-01

    A large number of alligators, flushed down toilets as babies, have grown up and proliferated in the bowels of New York City. Over the years, they have grown in number and size and frequently terrorize those foolish enough to visit the subways. This tale has been making its way around the Internet ever since there's been an Internet. It's wild…

  2. Flowers & Weeds.

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    1996-01-01

    Describes the topics and teaching strategies employed in an Issues in Biology course. Discusses flowers, plant breeding, potatoes and tomatoes, the chocolate tree, weeds, Arabidopis, gene transfers, and plant genes/human genes. Contains 22 references. (JRH)

  3. Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adaptive management can complement integrated programs to manage weeds in forage production systems. This approach requires establishing management goals, developing and implementing management programs based on the goals, monitoring and assessing impacts of management efforts, and modifying goals a...

  4. Weeding Your Collection.

    ERIC Educational Resources Information Center

    Kerby, Ramona

    2002-01-01

    Offers guidelines for weeding as part of school library collection development. Highlights include developing a weeding policy; and the CREW (Continuous Review Evaluation and Weeding) method, including reasons for weeding, scheduling, and guidelines for fiction and for nonfiction. (LRW)

  5. Distribution of ventilation in American alligator Alligator mississippiensis

    SciTech Connect

    Bickler, P.E.; Spragg, R.G.; Hartman, M.T.; White, F.N.

    1985-10-01

    The regional distribution of ventilation in the multicameral lung of spontaneously ventilating alligators (Alligator mississippiensis) was studied with TTXe scintigraphy. Frequent gamma camera images of TTXe washin and washout were obtained and processed to allow evaluation of regional ventilation. Washin of TTXe to equilibrium occurred in three to four breaths in anterior, central, and posterior compartments. Washin was most rapid in the posterior compartment and slowest in the anterior. The structure of the lungs and distribution of ventilation of inspired gas is consistent with the rapid radial spread of gas through a parallel arrangement of lung units surrounding the central intrapulmonary bronchus. Washout to equilibrium of TTXe from all compartments occurred within three to four breaths. This rapid washin and washout of gas to all parts of the lung stands in contrast to the lungs of turtles and snakes, in which the caudal air sacs are relatively poorly ventilated.

  6. Bioprospecting the American alligator (Alligator mississippiensis) host defense peptidome.

    PubMed

    Bishop, Barney M; Juba, Melanie L; Devine, Megan C; Barksdale, Stephanie M; Rodriguez, Carlos Alberto; Chung, Myung C; Russo, Paul S; Vliet, Kent A; Schnur, Joel M; van Hoek, Monique L

    2015-01-01

    Cationic antimicrobial peptides and their therapeutic potential have garnered growing interest because of the proliferation of bacterial resistance. However, the discovery of new antimicrobial peptides from animals has proven challenging due to the limitations associated with conventional biochemical purification and difficulties in predicting active peptides from genomic sequences, if known. As an example, no antimicrobial peptides have been identified from the American alligator, Alligator mississippiensis, although their serum is antimicrobial. We have developed a novel approach for the discovery of new antimicrobial peptides from these animals, one that capitalizes on their fundamental and conserved physico-chemical properties. This sample-agnostic process employs custom-made functionalized hydrogel microparticles to harvest cationic peptides from biological samples, followed by de novo sequencing of captured peptides, eliminating the need to isolate individual peptides. After evaluation of the peptide sequences using a combination of rational and web-based bioinformatic analyses, forty-five potential antimicrobial peptides were identified, and eight of these peptides were selected to be chemically synthesized and evaluated. The successful identification of multiple novel peptides, exhibiting antibacterial properties, from Alligator mississippiensis plasma demonstrates the potential of this innovative discovery process in identifying potential new host defense peptides. PMID:25671663

  7. Biophysics of directional hearing in the American alligator (Alligator mississippiensis)

    PubMed Central

    Bierman, Hilary S.; Thornton, Jennifer L.; Jones, Heath G.; Koka, Kanthaiah; Young, Bruce A.; Brandt, Christian; Christensen-Dalsgaard, Jakob; Carr, Catherine E.; Tollin, Daniel J.

    2014-01-01

    Physiological and anatomical studies have suggested that alligators have unique adaptations for spatial hearing. Sound localization cues are primarily generated by the filtering of sound waves by the head. Different vertebrate lineages have evolved external and/or internal anatomical adaptations to enhance these cues, such as pinnae and interaural canals. It has been hypothesized that in alligators, directionality may be enhanced via the acoustic coupling of middle ear cavities, resulting in a pressure difference receiver (PDR) mechanism. The experiments reported here support a role for a PDR mechanism in alligator sound localization by demonstrating that (1) acoustic space cues generated by the external morphology of the animal are not sufficient to generate location cues that match physiological sensitivity, (2) continuous pathways between the middle ears are present to provide an anatomical basis for coupling, (3) the auditory brainstem response shows some directionality, and (4) eardrum movement is directionally sensitive. Together, these data support the role of a PDR mechanism in crocodilians and further suggest this mechanism is a shared archosaur trait, most likely found also in the extinct dinosaurs. PMID:24671963

  8. Jumping the Alligators in the Ditch.

    ERIC Educational Resources Information Center

    Barber, Rims

    Poor black young people in rural Mississippi contemplate their schooling with the same feelings as their friends who dare to jump the local ditches filled with alligators: the odds are against escaping the alligators, and the advantages of getting to the far side are not very apparent. Living in conditions of extreme poverty, these young people…

  9. Green Weeding

    ERIC Educational Resources Information Center

    Penniman, Sarah; McColl, Lisa

    2008-01-01

    Gone are the days of tiptoeing to the dumpsters with boxes of weeded books in tow. Lots of libraries are now taking advantage of the many low-cost services and solutions that promise to help extend the lives of collection discards. Some of these options can be very profitable. Some create goodwill within the local community. Some may seem more…

  10. Winter Weeds.

    ERIC Educational Resources Information Center

    Lindberg, Lois

    1981-01-01

    Try to learn all you can about a plant in the winter. As the season changes, you can see what the dried seed pod is like in bloom. You are a convert if you notice a spectacular show of summer wildflowers and wonder what sort of winter weed will result. (Author/CM)

  11. Weed control without herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing weeds without herbicides is challenging and requires an integration of tactics and a change in how weeds problems are approached. Weeds should be managed in a holistic, intentional and proactive manner. Growers that successfully manage weeds in organic systems examine why certain weed speci...

  12. Biochar from Alternanthera philoxeroides could remove Pb(II) efficiently.

    PubMed

    Yang, Yu; Wei, Zhongbo; Zhang, Xiaolong; Chen, Xu; Yue, Dongmei; Yin, Qian; Xiao, Lin; Yang, Liuyan

    2014-11-01

    A novel bio-adsorbent was successfully synthesized by pyrolyzing Alternanthera philoxeroides (AP), one of the most widely used hydrophytes for eutrophic lake ecological restoration under O2-limited condition at 600 °C. Compared with commercially active carbon (AC), the initial solution pH had a weak effect on the adsorption of Pb(II) by AP biochar (APB). The maximum adsorption capacity of APB for Pb(II) was 257.12 mg/g, which was 5.3 times of that of the AC. The adsorption process was fast, with only 2.5h to reach adsorption equilibrium. The adsorption mechanism of Pb(II) by APB involves the precipitation and complexation of Pb(II) with free carboxyl/hydroxyl functional groups and mineral carbonates of APB as well as ion replacement between Pb(II) and alkaline earth cations. These results suggest that using a low-cost APB adsorbent for heavy metals contaminated water treatment may have great ecological and environmental significance. PMID:25203230

  13. Clonal integration in homogeneous environments increases performance of Alternanthera philoxeroides.

    PubMed

    Dong, Bi-Cheng; Alpert, Peter; Zhang, Qian; Yu, Fei-Hai

    2015-10-01

    Physiological integration between connected ramets can increase the performance of clonal plants when ramets experience contrasting levels of resource availabilities in heterogeneous environments. It has generally been shown or assumed that clonal integration has little effect on clonal performance in homogeneous environments. However, a conceptual model suggests that integration could increase performance in a homogeneous environment when connected ramets differ in uptake ability and external resource supply is high. We tested this hypothesis in a greenhouse experiment with the amphibious plant Alternanthera philoxeroides. Ramets in clonal fragments containing three rooted and two unrooted ramets were either left connected or divided into a basal part with two rooted ramets and an apical part with the other ramets. To simulate realistic, homogeneous environments of the species with different levels of resource supply, plants were grown at 0, 20, or 40 cm of water depth. Water depth had a positive effect on most measures of growth, indicating that resource supply increased with depth. Connection had negative to neutral effects on total growth of fragments at a water depth of 0 cm, and neutral to positive effects at 20- and 40-cm depths; effects on the apical part were generally positive and larger at greater depth; effects on the basal part were generally negative and smaller at greater depth. Results largely supported the hypothesis and further suggest that clonal integration of allocation and reproduction may modify benefits of resource sharing in homogeneous environments. PMID:26009243

  14. Alternanthera sessilis Red Ethyl Acetate Fraction Exhibits Antidiabetic Potential on Obese Type 2 Diabetic Rats

    PubMed Central

    Tan, Kok Keong; Kim, Kah Hwi

    2013-01-01

    The antidiabetic potential of Alternanthera sessilis Red was investigated using the obese type 2 diabetic rats induced by high fat diet and streptozotocin. Three fractions (hexane, ethyl acetate, and water) were obtained from the crude ethanol extract of Alternanthera sessilis Red. Alternanthera sessilis Red ethyl acetate fraction (ASEAF) was found to possess the most potent antihyperglycemic effect through oral glucose tolerance test. The ASEAF was subsequently given to the diabetic rats for two weeks. It was found that two-week administration of ASEAF reduces the fasting blood glucose level, triglyceride level, and free fatty acid level of the rats. ASEAF-treated diabetic rats showed higher pancreatic insulin content and pancreatic total superoxide dismutase activity compared to the untreated diabetic rats. Also, the insulin sensitivity indexes suggested that ASEAF ameliorates the insulin resistant state of the diabetic rats. In conclusion, ASEAF could be developed into a potential antidiabetic agent for the management of type 2 diabetes. PMID:23606892

  15. Coronary blood flow in the anesthetized American alligator (Alligator mississippiensis).

    PubMed

    Jensen, Bjarke; Elfwing, Magnus; Elsey, Ruth M; Wang, Tobias; Crossley, Dane A

    2016-01-01

    Coronary circulation of the heart evolved early within ectothermic vertebrates and became of vital importance to cardiac performance in some teleost fish, mammals and birds. In contrast, the role and function of the coronary circulation in ectothermic reptiles remains largely unknown. Here, we investigated the systemic and coronary arterial responses of five anesthetized juvenile American alligators (Alligator mississippiensis) to hypoxia, acetylcholine, adenosine, sodium nitroprusside, isoproterenol, and phenylephrine. We recorded electrocardiograms, monitored systemic blood pressure, blood flows in both aortae, and blood flow in a major coronary artery supplying most of the right ventricle. Coronary arterial blood flow was generally forward, but there was a brief retrograde flow during a ventricular contraction. Blood pressure was significantly changed in all conditions. Acetylcholine decreased coronary forward flow, but this response was confounded by the concomitant lowered work of the ventricles due to decreased heart rate and blood pressure. Coronary forward flow was poorly correlated with heart rate and mean arterial pressure across treatments. Overall changes in coronary forward flow, significant and not significant, were generally in the same direction as mean arterial pressure and ventricular power, approximated as the product of systemic cardiac output and mean arterial pressure. PMID:26436857

  16. On the variability of alligator sex ratios

    USGS Publications Warehouse

    Nichols, J.D.; Chabreck, R.H.

    1980-01-01

    Samples of alligators from wild and 'farm' populations exhibited disproportionate sex ratios. Males predominated among young alligators from wild populations, whereas females were much more abundant than males in the farm population, where resources were superabundant. These results and other considerations lead us to hypothesize that environmental factors influence sex determination in alligators. During favorable environmental conditions natural selection is expected to favor a preponderance of the sex whose individuals exhibit the greater environmentally associated variation in relative fitness. We hypothesize that environmentally associated variation in age at sexual maturity of females produces sufficient variation in relative fitness of females to result in selection for low sex ratios during periods of resource abundance.

  17. Non-parasitic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds lower potato yield and quality by competing for light, nutrients, water, and space. Weeds can also interfere with harvest operations. Weeds can be categorized into annual, biennial, and perennial based on their life cycle. Perennial weeds live for three years or more and reproduce by various t...

  18. POPS IN ALLIGATOR LIVERS FROM LAKE APOPKA, FLORIDA, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  19. SEASONAL VARIATION IN PLASMA SEX STEROID CONCENTRATION IN JUVENILE ALLIGATORS

    EPA Science Inventory

    Seasonal variation in plasma sex steroid concentrations is common in mature vertebrates, and is occasionally seen in juvenile animals. In this study, we examine the seasonal pattern of sex hormone concentration in juvenile American alligators (Alligator mississippiensis) and make...

  20. Occurrence of decabromodiphenyl ethane in captive Chinese alligators (Alligator sinensis) from China.

    PubMed

    Hong, Bing; Wu, Ting; Zhao, Guangchao; Sun, Yuxin; Wang, Xinming; Zhao, Juan; Yi, Zhigang; Wu, Xiaobing; Mai, Bixian

    2015-01-01

    Decabromodiphenyl ethane (DBDPE), a replacement for decabromodiphenyl ether (deca-BDE), was investigated in captive Chinese alligators from China. DBDPE was detected in adult tissues, neonates and eggs of Chinese alligators with concentrations ranging from 4.74-192, 0.24-1.94, and 0.01-0.51 ng g(-1) lipid weight, respectively. Compared to PBDEs and PCBs, DBDPE contamination was limited in Chinese alligators. Additionally, DBDPE concentrations in adult muscles were one to three orders of magnitude higher than those in neonates and eggs, suggesting the limited maternal transfer potential of DBDPE in Chinese alligators. This is the first study to report the occurrence of DBDPE in Chinese alligators. PMID:25159734

  1. Complete Genome Sequence of Alternanthera mosaic virus, Isolated from Achyranthes bidentata in Asia

    PubMed Central

    Iwabuchi, Nozomu; Yoshida, Tetsuya; Yusa, Akira; Nishida, Shuko; Tanno, Kazuyuki; Keima, Takuya; Nijo, Takamichi; Yamaji, Yasuyuki

    2016-01-01

    Alternanthera mosaic virus (AltMV) infecting Achyranthes bidentata was first detected in Asia, and the complete genome sequence (6,604 nucleotides) was determined. Sequence identity analysis and phylogenetic analysis confirmed that this isolate is the most phylogenetically distant AltMV isolate worldwide. PMID:26988034

  2. THYROID STATUS IN JUVENILE ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED AND REFERENCE SITES ON LAKE OKEECHOBEE, FLORIDA, USA

    EPA Science Inventory

    Exposure to environmental contaminants has been shown to alter normal thyroid function in various wildlife species, including the American alligator (Alligator mississippiensis). Abnormalities in circulating levels of the thyroid hormone thyroxine (T4) have been reported in juven...

  3. 75 FR 34365 - Safety Zone, Alligator River, NC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Alligator River, NC AGENCY: Coast Guard... the waters of the Alligator River at East Lake, North Carolina. The safety zone is intended to... on the Alligator River makes safety zone regulations necessary to provide for the safety...

  4. Systena silvestrii bechyne (Coleoptera:Chrysomelidae):Redescripton,new distribution and adult host records

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The flea beetle Systena silvestrii Bechyné 1957, was studied in context with the evaluation of natural enemies of the alligator weed, Alternanthera philoxeroides (Martius) Grisebach (Amaranthaceae). The female is described and the holotype male is redescribed adding new diagnostic characters: mouth...

  5. Endogenous and exogenous estrogens during embryonic development affect timing of hatch and growth in the American alligator (Alligator mississippiensis).

    PubMed

    Cruze, Lori; Roark, Alison M; Rolland, Gabrielle; Younas, Mona; Stacy, Nicole; Guillette, Louis J

    2015-06-01

    Prenatal exposure to estrogenic endocrine disrupting chemicals (EDCs) can affect length of gestation and body mass and size of offspring. However, the dose, timing, and duration of exposure as well as sex and strain of the experimental animals determine the direction and magnitude of these effects. In this study, we examined the effects of a one-time embryonic exposure to either 17 β-estradiol (E2) or bisphenol A (BPA) on rate of development and growth in American alligators (Alligator mississippiensis). Our results indicate that BPA and E2-treated alligators hatched approximately 1.4 days earlier than vehicle-treated (control) alligators, suggesting that estrogenic chemicals hasten hatching in these animals. We assessed growth rates, growth allometry, and body condition for 21 weeks after hatching and found that BPA-treated alligators grew more quickly shortly after hatching but more slowly thereafter compared to control alligators. Conversely, E2-treated alligators grew more slowly shortly after hatching but more quickly thereafter compared to control alligators. As a result of differences in growth rate, BPA-treated alligators were heavier, longer, and fatter than control alligators at age 5 weeks but were similar in size and leaner than control alligators at age 21 weeks. Biochemical analytes were examined at the end of the 21-week study to assess overall metabolic condition. We found that E2-treated alligators had significantly higher circulating plasma concentrations of cholesterol and triglycerides than control alligators while BPA-treated alligators had blood profiles comparable to control alligators. Our results provide important insights into the effects of exogenous estrogens on morphology and metabolism in an oviparous, semi-aquatic reptile. PMID:25687799

  6. An algae-covered alligator rests warily

    NASA Technical Reports Server (NTRS)

    2000-01-01

    An algae-covered alligator keeps a wary eye open as it rests in one of the ponds at Kennedy Space Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  7. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the water near Kennedy Space Center, a mother alligator gathers her six offspring. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  8. International Alligator Rivers Analog Project

    SciTech Connect

    Bichard, G.F.

    1988-01-01

    The Australian Nuclear Science and Technology Organization (ANSTO), the Japan Atomic Energy Research Institute, the Swedish Nuclear Power Inspectorate, the U.K. Department of the Environment, the US Nuclear Regulatory Commission (NRC), and the Power Reactor and Nuclear Fuel Development Corporation of Japan are participating under the aegis of the Nuclear Energy Agency in the International Alligator Rivers Analog Project. The project has a duration of 3 yr, starting in 1988. The project has grown out of a research program on uranium ore bodies as analogs of high-level waste (HLW) repositories undertaken by ANSTO supported by the NRC. A primary objective of the project is to develop an approach to radionuclide transport model validation that may be used by the participants to support assessments of the safety of radioactive waste repositories. The approach involves integrating mathematical and physical modeling with hydrological and geochemical field and laboratory investigations of the analog site. The Koongarra uranium ore body has been chosen as the analog site because it has a secondary ore body that has formed over the past million years as a result of leaching by groundwater flowing through fractures in the primary ore body.

  9. Horny Goat Weed

    MedlinePlus

    ... avoid using. Bleeding disorders: Horny goat weed slows blood clotting and might increase the risk of bleeding. However, ... risk of fainting. Surgery: Horny goat weed slows blood clotting and might increase the risk of bleeding during ...

  10. Eradication of Major Weeds

    ERIC Educational Resources Information Center

    Indian Journal of Adult Education, 1975

    1975-01-01

    Strategies for weed control in cropped and non-cropped areas are presented together with an operational plan for implementing a program for weed control at the national level. The program includes training personnel and community education procedures. (EC)

  11. ALTERATIONS IN SEXUALLY DIMORPHIC BIOTRANSFORMATION OF TESTOSTERONE IN JUVENILE AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED LAKES

    EPA Science Inventory

    The goal of this study was to determine whether hepatic biotransformation of testosterone is normally sexually dimorphic in juvenile alligators and whether living in a contaminated environment affects hepatic dimorphism. Lake Woodruff served as our reference site. Moonshine Bay, ...

  12. MORPHOLOGICAL VARIATION IN HATCHLING AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM THREE FLORIDA LAKES

    EPA Science Inventory

    Morphological variation of 508 hatchling alligators from three lakes in north central Florida (Lakes Woodruff, Apopka, and Orange) was analyzed using multivariate statistics. Morphological variation was found among clutches as well as among lakes. Principal components analysis wa...

  13. Home range and movements of American alligators (Alligator mississippiensis) in an estuary habitat

    USGS Publications Warehouse

    Fujisaki, Ikuko; Hart, Kristen M.; Mazzotti, Frank J.; Cherkiss, Michael S.; Sartain-Iverson, Autumn R.; Jeffery, Brian M.; Beauchamp, Jeffrey S.; Denton, Mathew J.

    2014-01-01

    This study reveals consistent use of estuary habitat by American alligators. The alligators showed variations in their movement pattern and seasonal habitat, with movement attributable to environmental factors. Although satellite-derived locations were more dispersed compared to locations collected using VHF radio-tags, data collected from VHF tracking omitted some habitat used for a short period of time, indicating the effectiveness of satellite telemetry to continuously track animals for ecosystem-scale studies.

  14. METALS AND METALLOIDS IN TISSUES OF AMERICAN ALLIGATORS IN THREE FLORIDA LAKES

    EPA Science Inventory

    Concentrations of metals and selenium were examined in tissues of American alligators (Alligator mississippiensis) from three lakes in central Florida, in one of which alligators have exhibited reproductive or developmental defects. Our overall objective was to determine whether ...

  15. Survival and growth of American alligator (Alligator mississippiensis) hatchlings after artificial incubation and repatriation

    USGS Publications Warehouse

    Temsiripong, Y.; Woodward, A.R.; Ross, J.P.; Kubilis, P.S.; Percival, H.F.

    2006-01-01

    Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and repatriated hatchlings released within and outside the maternal alligator's home range with naturally incubated hatchlings captured and released within the maternal alligator's home range on Lake Apopka, Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released outside of the maternal alligator's home range had lower recapture probabilities than either naturally incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching. We concluded that repatriation of hatchlings probably would not have long-term effects on populations because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation of older juveniles for population restoration. However, the location of release may affect subsequent survival and growth. Copyright 2006 Society for the Study of Amphibians and Reptiles.

  16. The isolation of parvalbumin isoforms from the tail muscle of the American alligator (Alligator mississipiensis).

    PubMed

    Laney, E L; Shabanowitz, J; King, G; Hunt, D F; Nelson, D J

    1997-04-01

    Multiple parvalbumin isoforms have been detected in the tail (skeletal) muscle of the American alligator (Alligator mississipiensis). One of these isoforms (APV-1) has been highly purified and partially characterized. Protein purification involved mainly gel filtration and anion exchange chromatography, and characterization included gel electrophoresis, amino acid composition analysis, metal ion analysis, MALDI-TOF and ESI mass spectrometry, ultraviolet and fluorescence spectroscopy, and one- and two-dimensional 500 MHz proton NMR spectroscopy. The alligator isoforms are rich in phenylalanine and deficient in the other aromatic residues as is typical for parvalbumins. In fact, the one highly purified isoform that forms the basis of this study has only phenyl-alanine as an aromatic residue. Ion exchange chromatography further indicates that this isoform has a relatively high isoelectric point (pl approximately 5.0), indicating that it is an alpha-lineage parvalbumin. This alligator parvalbumin isoform is unusual in that it has an atypically high Ca2+ content (almost 3.0 mole of Ca2+ per mole of protein) following purification, a fact supported by terbium fluorescence titration experiments. Preliminary comparative analysis of the highly purified alligator parvalbumin isoform (in the Ca2-loaded state) by two-dimensional 1H-NMR (2D 1H TOCSY and 2D 1H NOESY) indicates that there is considerable similarity in structure between the alligator protein and a homologous protein obtained from the silver hake (a saltwater fish species). PMID:9076974

  17. Urinary Phthalate Metabolites in American Alligators (Alligator mississippiensis) from Selected Florida Wetlands.

    PubMed

    Brock, John W; Bell, Jane Margaret; Guillette, Louis J

    2016-07-01

    Phthalates have been shown to cause endocrine disruption in laboratory animals and are associated with altered development of the reproductive system in humans. Further, human have significant exposure to phthalates. However, little is known concerning the exposure of wildlife to phthalates. We report urinary phthalate metabolite concentrations from fifty juvenile alligators from three Florida lakes and a site in the Everglades. Urinary phthalate monoester concentrations varied widely among alligators from the different sites but also among alligators from the same site. Mono-2-ethylhexy phthalate and monobutyl phthalate were found in most samples of alligator urine with maximums of 35,700 ng/mL and 193 ng/mL, respectively. Monobenzyl phthalate was found in 5 alligators with a maximum of 66.7 ng/mL. Other monoesters were found in only one or two alligator urine samples. The wide variation within and among sites, in addition to the high levels of mEHP, mBP and mBzP, is consistent with exposure arising from the intermittent spraying of herbicide formulations to control invasive aquatic plants in Florida freshwater sites. Phthalate diesters are used as adjuvants in many of these formulations. PMID:26743198

  18. Ecological studies on the American alligator (Alligator mississippiensis) on the Savannah River Plant

    SciTech Connect

    Seigel, R.A.; Brandt, L.A.; Knight, J.L.; Novak, S.S.

    1986-06-01

    The American alligator (Alligator mississippiensis) is the largest vertebrate of the Savannah River Plant (SRP), reaching a maximum length of 3.7 meters (12 feet) and weighing up to 175 kg (385 pounds). Currently, populations in coastal South Carolina are considered Threatened, whereas populations in inland areas (such as the SRP) are still Endangered. Because of their legal status and economic and ecological importance, it is important to determine the environmental impacts of SRP operations on the local alligator population. The major objectives under the Endangered Species Program of the Comprehensive Cooling Water Study (CCWS) were as follows: (1) document and compare the present status and distribution of alligators on the SRP to previous surveys, in order to determine long-term changes in population abundance; (2) establish baseline population and ecological parameters of the Steel Creek population so that the ecological effects of L-Reactor operations can be determined, and (3) conduct ecological research on the immediate impacts of thermal effluents on American alligators. Gladden et al., (1985) summarized data on previous population surveys, temporal changes in the Par Pond population, preliminary results of the Steel Creek surveys and Savannah River Ecology Laboratory (SREL) research on the effects of thermal effluents. This report summarizes the current status of the SRP population, presents data on the abundance, movement patterns and activity cycles of the Steel Creek population, and presents additional data on the effect of cooling water releases on alligator ecology and behavior.

  19. Crocodiles and Alligators. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    Farre, Marie

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes the physical characteristics, behavior, and peculiar habits of crocodiles, including how to distinguish them from close relatives such as alligators, cayman, and gharials. (YP)

  20. [Effects of perchlorate on growth and chlorophyll fluorescence parameters of Alternanthera philoxeroides].

    PubMed

    Xie, Yin-feng; Cai, Xian-lei; Liu, Wei-long; Deng, Wei

    2009-08-15

    Perchlorate is a new emerging persistent pollutant, while no studies about its effects on plants have been reported both home and abroad. In order to explore the effects of perchlorate on growth and physiology of aquatic plant, Alternanthera philoxeroides were treated by 1/20 Hoagland nutrient solution with different concentrations (0, 1, 5, 20, 100, 500 mg/L) of ClO4- under the controlled conditions. The results showed as follow. (1) Under perchlorate treatment, relative growth yield,dry weight of root,shoot and leaves were inhibited at different degrees, in which root biomass under different treatments showed significant difference to the control. After treatment for 40 d, relative growth yield of different treatments at concentration from 1 mg/L to 500 mg/L were about 61.6%, 60.8%, 53.1%, 20.4% and 3.3% separately of the control. And the order of variation coefficients of biomass in different organ were as follows: leaf > root biomass > stem; the relationship of biomass allocation in different organs of Alternanthera philoxeroides under perchlorate treatment changed, and the proportion of stem biomass increased,while leaf decreased, in which 100 and 500 mg/L ClO4- treatment showed significant difference to the control. (2) Under perchlorate treatment, young leaves of Alternanthera philoxeroides presented injury symptoms (such as parietal roiling reversely, leaf edge getting black and withered etc), and the damaged degree of Alternanthera philoxeroides increased with the increase of treatment concentration and time. (3) Under perchlorate treatment, the relative chlorophyll content (SPAD value), primary maximal PSII efficiency(Fv/Fm), efficiency of excitation capture by open PSII centre (F'v,/F'm), actual photochemical efficiency of PSII (phi(PS II)), electron transport rate (ETR), maximal electron transport rate(ETR ,) and other indexes were inhibited at different degrees. SPAD and chlorophyll fluorescence parameters (phi(PS II)) etc. could be used as sensitive

  1. Elemental Levels Analyzed by PIXE in Florida Alligators

    SciTech Connect

    Kuharik, J.C.; Kravchenko, I.I.; Dunnam, F.E.; Rinsvelt, H.A. van; Ross, J.P.

    2003-08-26

    Unusual and alarming mortality of alligators (Alligator mississippiensis) has been reported from Lake Griffin, Florida, where almost 400 dead alligators have been observed since 1997. In addition, the hatch rate for alligator eggs around Lake Griffin fell below 10% and remains low (30-45%) while the normal hatch rate is typically 80%. Standard diagnostic methods have been ineffective in determining the cause of the phenomenon. Many possibilities have been considered including pollutants, nutrition, and toxic algae. Particle Induced X-ray Emission (PIXE) analysis is highly suitable for investigating concentrations of a wide range of elements in animal tissue. Liver, kidney and spinal cord tissues from healthy and sick alligators have been analyzed by PIXE for elemental content. Initial results showed positive correlation between certain elements and neural impairment and morbidity of alligators in Lake Griffin, but have failed to prove significant.

  2. Elemental Levels Analyzed by PIXE in Florida Alligators

    NASA Astrophysics Data System (ADS)

    Kuharik, J. C.; Kravchenko, I. I.; Dunnam, F. E.; Van Rinsvelt, H. A.; Ross, J. P.

    2003-08-01

    Unusual and alarming mortality of alligators (Alligator mississippiensis) has been reported from Lake Griffin, Florida, where almost 400 dead alligators have been observed since 1997. In addition, the hatch rate for alligator eggs around Lake Griffin fell below 10% and remains low (30-45%) while the normal hatch rate is typically 80%. Standard diagnostic methods have been ineffective in determining the cause of the phenomenon. Many possibilities have been considered including pollutants, nutrition, and toxic algae. Particle Induced X-ray Emission (PIXE) analysis is highly suitable for investigating concentrations of a wide range of elements in animal tissue. Liver, kidney and spinal cord tissues from healthy and sick alligators have been analyzed by PIXE for elemental content. Initial results showed positive correlation between certain elements and neural impairment and morbidity of alligators in Lake Griffin, but have failed to prove significant.

  3. Levels of mercury in alligators (Alligator mississippiensis) collected along a transect through the Florida Everglades

    USGS Publications Warehouse

    Rumbold, D.G.; Fink, L.E.; Laine, K.A.; Niemczyk, S.L.; Chandrasekhar, T.; Wankel, Scott D.; Kendall, C.

    2002-01-01

    As part of a multi-agency study of alligator health, 28 American alligators (Alligator mississippiensis) were captured along a transect through the Florida Everglades in 1999. Liver and tail muscle tissues were sampled and analyzed on a wet weight basis for total mercury (THg) using cold-vapor atomic absorption spectrophotometry. All tissues had detectable concentrations of THg that ranged from 0.6 to 17 mg/kg in liver and from 0.1 to 1.8 mg/kg in tail muscle. THg was more concentrated in liver tissue than tail muscle, but levels were highly correlated between tissues. THg concentrations in tissue differed significantly among locations, with animals from Everglades National Park (ENP) having mean concentrations of THg in liver (10.4 mg/kg) and tail muscle (1.2 mg/kg) that were two-fold higher than basin-wide averages (4.9 and 0.64 mg/kg, respectively). The reasons for higher contamination of ENP alligators were unclear and could not be explained by differences in sex, length, weight or animal age. While ??15N values were positively correlated with THg concentrations in tail muscle, spatial patterns in isotopic composition did not explain the elevated THg levels in ENP alligators. Therefore, it appears that ENP alligators were more highly exposed to mercury in their environment than individuals in other areas. Comparisons to a previous survey by Yanochko et al. [Arch Environ Contam Toxicol 32 (1997) 323] suggest that mercury levels have declined in some Everglades alligators since 1994. ?? 2002 Elsevier Science B.V. All rights reserved.

  4. Introduction to Weeds and Herbicides.

    ERIC Educational Resources Information Center

    Hartwig, Nathan L.

    This agriculture extension service publication from Pennsylvania State University is an introduction to weed control and herbicide use. An initial discussion of the characteristics of weeds includes scientific naming, weed competition with crops, weed dispersal and dormancy, and conditions affecting weed seed germination. The main body of the…

  5. Identification and Characterization of the Androgen Receptor From the American Alligator, Alligator mississippiensis

    PubMed Central

    Miyagawa, Shinichi; Yatsu, Ryohei; Kohno, Satomi; Doheny, Brenna M.; Ogino, Yukiko; Ishibashi, Hiroshi; Katsu, Yoshinao; Ohta, Yasuhiko; Guillette, Louis J.

    2015-01-01

    Androgens are essential for the development, reproduction, and health throughout the life span of vertebrates, particularly during the initiation and maintenance of male sexual characteristics. Androgen signaling is mediated by the androgen receptor (AR), a member of the steroid nuclear receptor superfamily. Mounting evidence suggests that environmental factors, such as exogenous hormones or contaminants that mimic hormones, can disrupt endocrine signaling and function. The American alligator (Alligator mississippiensis), a unique model for ecological research in that it exhibits environment-dependent sex determination, is oviparous and long lived. Alligators from a contaminated environment exhibit low reproductive success and morphological disorders of the testis and phallus in neonates and juveniles, both associated with androgen signaling; thus, the alterations are hypothesized to be related to disrupted androgen signaling. However, this line of research has been limited because of a lack of information on the alligator AR gene. Here, we isolated A mississippiensis AR homologs (AmAR) and evaluated receptor-hormone/chemical interactions using a transactivation assay. We showed that AmAR responded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p′-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly, we found a spliced form of the AR from alligator cDNA, which lacks seven amino acids within the ligand-binding domain that shows no response to androgens. Finally, we have initial data on a possible dominant-negative function of the spliced form of the AR against androgen-induced AmAR. PMID:25974402

  6. Blood and Plasma Biochemistry Reference Intervals for Wild Juvenile American Alligators ( Alligator mississippiensis ).

    PubMed

    Hamilton, Matthew T; Kupar, Caitlin A; Kelley, Meghan D; Finger, John W; Tuberville, Tracey D

    2016-07-01

    : American alligators ( Alligator mississippiensis ) are one of the most studied crocodilian species in the world, yet blood and plasma biochemistry information is limited for juvenile alligators in their northern range, where individuals may be exposed to extreme abiotic and biotic stressors. We collected blood samples over a 2-yr period from 37 juvenile alligators in May, June, and July to establish reference intervals for 22 blood and plasma analytes. We observed no effect of either sex or blood collection time on any analyte investigated. However, our results indicate a significant correlation between a calculated body condition index and aspartate aminotransferase and creatine kinase. Glucose, total protein, and potassium varied significantly between sampling sessions. In addition, glucose and potassium were highly correlated between the two point-of-care devices used, although they were significantly lower with the i-STAT 1 CG8+ cartridge than with the Vetscan VS2 Avian/Reptile Rotor. The reference intervals presented herein should provide baseline data for evaluating wild juvenile alligators in the northern portion of their range. PMID:27224213

  7. Hypoxic alligator embryos: chronic hypoxia, catecholamine levels and autonomic responses of in ovo alligators.

    PubMed

    Eme, John; Altimiras, Jordi; Hicks, James W; Crossley, Dane A

    2011-11-01

    Hypoxia is a naturally occurring environmental challenge for embryonic reptiles, and this is the first study to investigate the impact of chronic hypoxia on the in ovo development of autonomic cardiovascular regulation and circulating catecholamine levels in a reptile. We measured heart rate (f(H)) and chorioallantoic arterial blood pressure (MAP) in normoxic ('N21') and hypoxic-incubated ('H10'; 10% O(2)) American alligator embryos (Alligator mississippiensis) at 70, 80 and 90% of development. Embryonic alligator responses to adrenergic blockade with propranolol and phentolamine were very similar to previously reported responses of embryonic chicken, and demonstrated that embryonic alligator has α and β-adrenergic tone over the final third of development. However, adrenergic tone originates entirely from circulating catecholamines and is not altered by chronic hypoxic incubation, as neither cholinergic blockade with atropine nor ganglionic blockade with hexamethonium altered baseline cardiovascular variables in N21 or H10 embryos. In addition, both atropine and hexamethonium injection did not alter the generally depressive effects of acute hypoxia - bradycardia and hypotension. However, H10 embryos showed significantly higher levels of noradrenaline and adrenaline at 70% of development, as well as higher noradrenaline at 80% of development, suggesting that circulating catecholamines reach maximal levels earlier in incubation for H10 embryos, compared to N21 embryos. Chronically elevated levels of catecholamines may alter the normal balance between α and β-adrenoreceptors in H10 alligator embryos, causing chronic bradycardia and hypotension of H10 embryos measured in normoxia. PMID:21798363

  8. Identification and Characterization of the Androgen Receptor From the American Alligator, Alligator mississippiensis.

    PubMed

    Miyagawa, Shinichi; Yatsu, Ryohei; Kohno, Satomi; Doheny, Brenna M; Ogino, Yukiko; Ishibashi, Hiroshi; Katsu, Yoshinao; Ohta, Yasuhiko; Guillette, Louis J; Iguchi, Taisen

    2015-08-01

    Androgens are essential for the development, reproduction, and health throughout the life span of vertebrates, particularly during the initiation and maintenance of male sexual characteristics. Androgen signaling is mediated by the androgen receptor (AR), a member of the steroid nuclear receptor superfamily. Mounting evidence suggests that environmental factors, such as exogenous hormones or contaminants that mimic hormones, can disrupt endocrine signaling and function. The American alligator (Alligator mississippiensis), a unique model for ecological research in that it exhibits environment-dependent sex determination, is oviparous and long lived. Alligators from a contaminated environment exhibit low reproductive success and morphological disorders of the testis and phallus in neonates and juveniles, both associated with androgen signaling; thus, the alterations are hypothesized to be related to disrupted androgen signaling. However, this line of research has been limited because of a lack of information on the alligator AR gene. Here, we isolated A mississippiensis AR homologs (AmAR) and evaluated receptor-hormone/chemical interactions using a transactivation assay. We showed that AmAR responded to all natural androgens and their effects were inhibited by cotreatment with antiandrogens, such as flutamide, p,p'-dichlorodiphenyldichloroethylene, and vinclozolin. Intriguingly, we found a spliced form of the AR from alligator cDNA, which lacks seven amino acids within the ligand-binding domain that shows no response to androgens. Finally, we have initial data on a possible dominant-negative function of the spliced form of the AR against androgen-induced AmAR. PMID:25974402

  9. Exhaustive exercise training enhances aerobic capacity in American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Owerkowicz, Tomasz; Gwalthney, June; Blank, Jason M; Rourke, Bryan C; Hicks, James W

    2009-11-01

    The oxygen transport system in mammals is extensively remodelled in response to repeated bouts of activity, but many reptiles appear to be 'metabolically inflexible' in response to exercise training. A recent report showed that estuarine crocodiles (Crocodylus porosus) increase their maximum metabolic rate in response to exhaustive treadmill training, and in the present study, we confirm this response in another crocodilian, American alligator (Alligator mississippiensis). We further specify the nature of the crocodilian training response by analysing effects of training on aerobic [citrate synthase (CS)] and anaerobic [lactate dehydrogenase (LDH)] enzyme activities in selected skeletal muscles, ventricular and skeletal muscle masses and haematocrit. Compared to sedentary control animals, alligators regularly trained for 15 months on a treadmill (run group) or in a flume (swim group) exhibited peak oxygen consumption rates higher by 27 and 16%, respectively. Run and swim exercise training significantly increased ventricular mass (~11%) and haematocrit (~11%), but not the mass of skeletal muscles. However, exercise training did not alter CS or LDH activities of skeletal muscles. Similar to mammals, alligators respond to exercise training by increasing convective oxygen transport mechanisms, specifically heart size (potentially greater stroke volume) and haematocrit (increased oxygen carrying-capacity of the blood). Unlike mammals, but similar to squamate reptiles, alligators do not also increase citrate synthase activity of the skeletal muscles in response to exercise. PMID:19533151

  10. Low cost of pulmonary ventilation in American alligators (Alligator mississippiensis) stimulated with doxapram.

    PubMed

    Skovgaard, Nini; Crossley, Dane A; Wang, Tobias

    2016-04-01

    To determine the costs of pulmonary ventilation without imposing severe oxygen limitations or acidosis that normally accompany exposures to hypoxia or hypercapnia, we opted to pharmacologically stimulate ventilation with doxapram (5 and 10 mg kg(-1)) in alligators. Doxapram is used clinically to alleviate ventilatory depression in response to anaesthesia and acts primarily on the peripheral oxygen-sensitive chemoreceptors. Using this approach, we investigated the hypothesis that pulmonary ventilation is relatively modest in comparison to resting metabolic rate in crocodilians and equipped seven juvenile alligators with masks for concurrent determination of ventilation and oxygen uptake. Doxapram elicited a dose-dependent and up to fourfold rise in ventilation, primarily by increasing ventilatory frequency. The accompanying rise in oxygen uptake was very small; ventilation in resting animals constitutes no more than 5% of resting metabolic rate. The conclusion that pulmonary ventilation is energetically cheap is consistent with earlier studies on alligators where ventilation was stimulated by hypoxia or hypercapnia. PMID:26896538

  11. A mother alligator protects her young

    NASA Technical Reports Server (NTRS)

    2000-01-01

    American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Center shares a boundary with the Merritt Island National Wildlife Refuge, which encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  12. In ovo and in vitro susceptibility of American alligators (Alligator mississippiensis) to avian influenza virus infection.

    PubMed

    Temple, Bradley L; Finger, John W; Jones, Cheryl A; Gabbard, Jon D; Jelesijevic, Tomislav; Uhl, Elizabeth W; Hogan, Robert J; Glenn, Travis C; Tompkins, S Mark

    2015-01-01

    Avian influenza has emerged as one of the most ubiquitous viruses within our biosphere. Wild aquatic birds are believed to be the primary reservoir of all influenza viruses; however, the spillover of H5N1 highly pathogenic avian influenza (HPAI) and the recent swine-origin pandemic H1N1 viruses have sparked increased interest in identifying and understanding which and how many species can be infected. Moreover, novel influenza virus sequences were recently isolated from New World bats. Crocodilians have a slow rate of molecular evolution and are the sister group to birds; thus they are a logical reptilian group to explore susceptibility to influenza virus infection and they provide a link between birds and mammals. A primary American alligator (Alligator mississippiensis) cell line, and embryos, were infected with four, low pathogenic avian influenza (LPAI) strains to assess susceptibility to infection. Embryonated alligator eggs supported virus replication, as evidenced by the influenza virus M gene and infectious virus detected in allantoic fluid and by virus antigen staining in embryo tissues. Primary alligator cells were also inoculated with the LPAI viruses and showed susceptibility based upon antigen staining; however, the requirement for trypsin to support replication in cell culture limited replication. To assess influenza virus replication in culture, primary alligator cells were inoculated with H1N1 human influenza or H5N1 HPAI viruses that replicate independent of trypsin. Both viruses replicated efficiently in culture, even at the 30 C temperature preferred by the alligator cells. This research demonstrates the ability of wild-type influenza viruses to infect and replicate within two crocodilian substrates and suggests the need for further research to assess crocodilians as a species potentially susceptible to influenza virus infection. PMID:25380354

  13. HISTOPATHOLOGY OF GASTRIC WALL IN CHINESE ALLIGATOR ALLIGATOR SINENSIS INFECTED WITH ORTLEPPASCARIS SINENSIS (NEMATODA: ASCARIDOIDEA).

    PubMed

    Zhao, Jinhong; Wang, Shaosheng; Tu, Genjun; Zhou, Yongkang; Wu, Xiaobing; Li, Chaopin

    2015-01-01

    Crocodiles are susceptible to infection with a wide array of external and internal gastrointestinal helminths, yet little is known on the histopathology following infection or the effects of these parasites. The present study was aimed at evaluating the impact of infection by Ortleppascaris sinensis (Nematoda: Ascaridoidea) on the stomach of captive Alligator sinensis. The histological examination of the stomach revealed presence of superficial ulcer in mucous layer and granulomatous inflammation in submucous layer at entire gastric walls of the Alligator sinensis. Our findings also confirm that development of Ortleppascaris sinensis is in close association with the wall of the stomach. PMID:26319836

  14. Hexavalent chromium is cytotoxic and genotoxic to American alligator cells.

    PubMed

    Wise, Sandra S; Wise, Catherine; Xie, Hong; Guillette, Louis J; Zhu, Cairong; Wise, John Pierce; Wise, John Pierce

    2016-02-01

    Metals are a common pollutant in the aquatic ecosystem. With global climate change, these levels are anticipated to rise as lower pH levels allow sediment bound metals to be released. The American alligator (Alligator mississippiensis) is an apex predator in the aquatic ecosystem and is considered a keystone species; as such it serves as a suitable monitor for localized pollution. One metal of increasing concern is hexavalent chromium (Cr(VI)). It is present in the aquatic environment and is a known human carcinogen and reproductive toxicant. We measured the cytotoxicity and genotoxicity of Cr(VI) in American alligator cells derived from scute tissue. We found that particulate and soluble Cr(VI) are both cytotoxic and genotoxic to alligator cells in a concentration-dependent manner. These data suggest that alligators may be used as a model for assessing the effects of environmental Cr(VI) contamination as well as for other metals of concern. PMID:26730726

  15. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of high quality and high yielding peppermint and spearmint oil requires effective management of weeds. Since soil disturbance is kept to a minimum to reduce the spread of Verticillium wilt in mint production, weed control is accomplished primarily with herbicides. Flucarbazone, and propox...

  16. Mustard meal weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic production systems can be a labor intensive and expensive process. Mustard meal (MM) is phytotoxic and a potential pre-emergent and preplant-incorporated organic herbicide for controlling germinating and emerging weed seedlings. Unfortunately, MM may also adversely impact s...

  17. Herbicide Resistant Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metribuzin and rimsulfuron are the only two herbicides registered for postemergence broadleaf weed control in potatoes, and represent the two classes of herbicides, triazines and ALS inhibitors, with the most reported cases of resistant weeds world wide. Other postemergence grass herbicides belongin...

  18. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds present in peppermint and spearmint reduce mint oil yield and quality. Mustard seed meal applied at 1 and 2 ton/acre to newly planted peppermint reduced annual weed emergence for several weeks without injuring peppermint. Field pennycress seed meal applied at similar rates did not suppress wee...

  19. Bioherbicides for Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Following the first commercially successfully biological control of weeds with fungal pathogens a model for a good bioherbicide was developed. It was assumed that a good agent was one that could be grown cheaply and quickly; was aggressive and patentable; could be easily applied; had single-weed sp...

  20. Pathology, physiologic parameters, tissue contaminants, and tissue thiamine in morbid and healthy central Florida adult American alligators (Alligator mississippiensis).

    PubMed

    Honeyfield, Dale C; Ross, J Perran; Carbonneau, Dwayne A; Terrell, Scott P; Woodward, Allan R; Schoeb, Trenton R; Perceval, H Franklin; Hinterkopf, Joy P

    2008-04-01

    An investigation of adult alligator (Alligator mississippiensis) mortalities in Lake Griffin, central Florida, was conducted from 1998-2004. Alligator mortality was highest in the months of April and May and annual death count peaked in 2000. Bacterial pathogens, heavy metals, and pesticides were not linked with the mortalities. Blood chemistry did not point to any clinical diagnosis, although differences between impaired and normal animals were noted. Captured alligators with signs of neurologic impairment displayed unresponsive and uncoordinated behavior. Three of 21 impaired Lake Griffin alligators were found to have neural lesions characteristic of thiamine deficiency in the telencephalon, particularly the dorsal ventricular ridge. In some cases, lesions were found in the thalamus, and parts of the midbrain. Liver and muscle tissue concentrations of thiamine (vitamin B(1)) were lowest in impaired Lake Griffin alligators when compared to unimpaired alligators or to alligators from Lake Woodruff. The consumption of thiaminase-positive gizzard shad (Dorosoma cepedianum) is thought to have been the cause of the low tissue thiamine and resulting mortalities. PMID:18436661

  1. Pathology, physiologic parameters, tissue contaminants, and tissue thiamine in morbid and healthy central Florida adult American alligators (Alligator mississippiensis)

    USGS Publications Warehouse

    Honeyfield, D.C.; Ross, J.P.; Carbonneau, D.A.; Terrell, S.P.; Woodward, A.R.; Schoeb, T.R.; Perceval, H.F.; Hinterkopf, J.P.

    2008-01-01

    An investigation of adult alligator (Alligator mississippiensis) mortalities in Lake Griffin, central Florida, was conducted from 1998-2004. Alligator mortality was highest in the months of April and May and annual death count peaked in 2000. Bacterial pathogens, heavy metals, and pesticides were not linked with the mortalities. Blood chemistry did not point to any clinical diagnosis, although differences between impaired and normal animals were noted. Captured alligators with signs of neurologic impairment displayed unresponsive and uncoordinated behavior. Three of 21 impaired Lake Griffin alligators were found to have neural lesions characteristic of thiamine deficiency in the telencephalon, particularly the dorsal ventricular ridge. In some cases, lesions were found in the thalamus, and parts of the midbrain. Liver and muscle tissue concentrations of thiamine (vitamin B"1) were lowest in impaired Lake Griffin alligators when compared to unimpaired alligators or to alligators from Lake Woodruff. The consumption of thiaminase-positive gizzard shad (Dorosoma cepedianum) is thought to have been the cause of the low tissue thiamine and resulting mortalities. ?? Wildlife Disease Association 2008.

  2. Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis).

    PubMed

    Tate, Kevin B; Rhen, Turk; Eme, John; Kohl, Zachary F; Crossley, Janna; Elsey, Ruth M; Crossley, Dane A

    2016-06-01

    During embryonic development, environmental perturbations can affect organisms' developing phenotype, a process known as developmental plasticity. Resulting phenotypic changes can occur during discrete, critical windows of development. Critical windows are periods when developing embryos are most susceptible to these perturbations. We have previously documented that hypoxia reduces embryo size and increases relative heart mass in American alligator, and this study identified critical windows when hypoxia altered morphological, cardiovascular function and cardiac gene expression of alligator embryos. We hypothesized that incubation in hypoxia (10% O2) would increase relative cardiac size due to cardiac enlargement rather than suppression of somatic growth. We exposed alligator embryos to hypoxia during discrete incubation periods to target windows where the embryonic phenotype is altered. Hypoxia affected heart growth between 20 and 40% of embryonic incubation, whereas somatic growth was affected between 70 and 90% of incubation. Arterial pressure was depressed by hypoxic exposure during 50-70% of incubation, whereas heart rate was depressed in embryos exposed to hypoxia during a period spanning 70-90% of incubation. Expression of Vegf and PdgfB was increased in certain hypoxia-exposed embryo treatment groups, and hypoxia toward the end of incubation altered β-adrenergic tone for arterial pressure and heart rate. It is well known that hypoxia exposure can alter embryonic development, and in the present study, we have identified brief, discrete windows that alter the morphology, cardiovascular physiology, and gene expression in embryonic American alligator. PMID:27101296

  3. Polychlorinated biphenyls in eggs and chlorioallantoic membranes of American alligators (Alligator mississippiensis) from coastal South Carolina

    SciTech Connect

    Cobb, G.P.; Wood, P.D.; O`Quinn, M.

    1997-07-01

    Assessing chemical exposure in threatened or endangered wildlife species presents unique analytical problems. Chorioallantoic membranes (CAMs) have been proposed as surrogate tissues for evaluation of polychlorinated biphenyl (PCB) exposure in oviparous species. Research was undertaken to determine the extent of PCB accumulation in alligators (Alligator mississippiensis) at sites along the coast of South Carolina and to evaluate the utility of CAMs as surrogate tissues for determining PCB concentrations in whole alligator eggs. Polychlorinated biphenyls were found in eggs and CAMs of alligators from both sites examined. Concentrations of PCBs were higher in CAMs (p = 0.02) and eggs (p = 0.001) from sites known to contain chlorinated hydrocarbons than from more pristine sites. Total PCBs partitioned predictably (r{sup 2} > 0.59; p < 0.02) between egg and CAM tissues indicating the utility of CAMs to serve as surrogate tissues when comparing total PCB concentrations in whole eggs. Tetrachloro through octachloro biphenyl homologues and total PCBs in CAMs from reference areas were correlated with concentrations of these homologues in eggs. At contaminated sites, total PCB concentrations in CAMs were correlated with total PCB concentrations in eggs.

  4. Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis).

    PubMed

    Nilsen, Frances M; Parrott, Benjamin B; Bowden, John A; Kassim, Brittany L; Somerville, Stephen E; Bryan, Teresa A; Bryan, Colleen E; Lange, Ted R; Delaney, J Patrick; Brunell, Arnold M; Long, Stephen E; Guillette, Louis J

    2016-03-01

    Mercury is a widespread environmental contaminant with exposures eliciting a well-documented catalog of adverse effects. Yet, knowledge regarding the underlying mechanisms by which mercury exposures are translated into biological effects remains incomplete. DNA methylation is an epigenetic modification that is sensitive to environmental cues, and alterations in DNA methylation at the global level are associated with a variety of diseases. Using a liquid chromatography tandem mass spectrometry-based (LC-MS/MS) approach, global DNA methylation levels were measured in red blood cells of 144 wild American alligators (Alligator mississippiensis) from 6 sites with variable levels of mercury contamination across Florida's north-south axis. Variation in mercury concentrations measured in whole blood was highly associated with location, allowing the comparison of global DNA methylation levels across different "treatments" of mercury. Global DNA methylation in alligators across all locations was weakly associated with increased mercury exposure. However, a much more robust relationship was observed in those animals sampled from locations more highly contaminated with mercury. Also, similar to other vertebrates, global DNA methylation appears to decline with age in alligators. The relationship between age-associated loss of global DNA methylation and varying mercury exposures was examined to reveal a potential interaction. These findings demonstrate that global DNA methylation levels are associated with mercury exposure, and give insights into interactions between contaminants, aging, and epigenetics. PMID:26748003

  5. Perfluorinated Alkyl Acids in Plasma of American Alligators (Alligator Mississippiensis) from Florida and South Carolina

    NASA Technical Reports Server (NTRS)

    Bangma, Jacqueline T.; Bowden, John A.; Brunell, Arnold M.; Christie, Ian; Finnell, Brendan; Guillette, Matthew P.; Jones, Martin; Lowers, Russell H.; Rainwater, Thomas R.; Reiner, Jessica L.; Wilkinson, Philip M.; Guillette, Louis J., Jr.

    2016-01-01

    This study aimed to quantitate fourteen perfluoroalkyl acids (PFAAs) in 125 adult American alligators at twelve sites across the southeastern US. Of those fourteen PFAAs, nine were detected in 65% - 100% of the samples: PFOA, PFNA, PFDA, PFUnA, PFDoA, PFTriA, PFTA, PFHxS, and PFOS. Males (across all sites) showed significantly higher concentrations of four PFAAs: PFOS (p = 0.01), PFDA (p = 0.0003), PFUnA (p = 0.021), and PFTriA (p = 0.021). Concentrations of PFOS, PFHxS, and PFDA in plasma were significantly different among the sites in each sex. Alligators at Merritt Island National Wildlife Refuge and Kiawah Nature Conservancy both exhibited some of the highest PFOS concentrations (medians 99.5 ng/g and 55.8 ng/g respectively) in plasma measured to date in a crocodilian species. A number of positive correlations between PFAAs and snout-vent length (SVL) were observed in both sexes suggesting PFAA body burdens increase with increasing size. In addition, several significant correlations among PFAAs in alligator plasma may suggest conserved sources of PFAAs at each site throughout the greater study area. This study is the first to report PFAAs in American alligators, reveals potential PFAA hot spots in Florida and South Carolina, and provides and additional contaminant of concern when assessing anthropogenic impacts on ecosystem health.

  6. Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis)

    PubMed Central

    Nilsen, Frances M.; Parrott, Benjamin B.; Bowden, John A.; Kassim, Brittany L.; Somerville, Stephen E.; Bryan, Teresa A.; Bryan, Colleen E.; Lange, Ted R.; Delaney, J. Patrick; Brunell, Arnold M.; Long, Stephen E.; Guillette, Louis J.

    2016-01-01

    Mercury is a widespread environmental contaminant with exposures eliciting a well-documented catalog of adverse effects. Yet, knowledge regarding the underlying mechanisms by which mercury exposures are translated into biological effects remains incomplete. DNA methylation is an epigenetic modification that is sensitive to environmental cues, and alterations in DNA methylation at the global level are associated with a variety of diseases. Using a liquid chromatography tandem mass spectrometry-based (LC-MS/MS) approach, global DNA methylation levels were measured in red blood cells of 144 wild American alligators (Alligator mississippiensis) from 6 sites with variable levels of mercury contamination across Florida’s north-south axis. Variation in mercury concentrations measured in whole blood was highly associated with location, allowing the comparison of global DNA methylation levels across different “treatments” of mercury. Global DNA methylation in alligators across all locations was weakly associated with increased mercury exposure. However, a much more robust relationship was observed in those animals sampled from locations more highly contaminated with mercury. Also, similar to other vertebrates, global DNA methylation appears to decline with age in alligators. The relationship between age-associated loss of global DNA methylation and varying mercury exposures was examined to reveal a potential interaction. These findings demonstrate that global DNA methylation levels are associated with mercury exposure, and give insights into interactions between contaminants, aging, and epigenetics. PMID:26748003

  7. Molecular and functional characterization of BAFF from the Yangtze alligator (Alligator sinensis, Alligatoridae).

    PubMed

    Zhang, Jia-Xin; Song, Ren; Sang, Ming; Sun, Si-Qing; Ma, Lei; Zhang, Jie; Zhang, Shuang-Quan

    2015-10-01

    B-cell activating factor (BAFF) from the TNF family is critical for B-cell survival and maturation. In this study, we identified a Yangtze alligator (Alligator sinensis, Alligatoridae) BAFF cDNA, designated as asBAFF, using reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The open reading frame of this cDNA encodes a 287-amino acid protein containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian and avian BAFF. The amino acid identity between biologically soluble asBAFF (assBAFF) and csBAFF, hsBAFF, and msBAFF is 94, 76, and 71%, respectively. Real-time quantitative PCR analysis showed that the asBAFF gene is strongly expressed in the spleen. Since BAFF is always expressed as inclusion bodies in bacteria, it is difficult to purify. To enhance the soluble expression of assBAFF in Escherichia coli, we fused the extracellular region of the asBAFF gene to a small ubiquitin-related modifier gene (SUMO). Purified assBAFF was able to promote the survival of splenic lymphocytes and co-stimulate the proliferation of mouse B cells with anti-mouse IgM. These findings suggest that asBAFF plays an important role in the survival and proliferation of Yangtze alligator B cells, and because it is evolutionarily highly conserved, functional cross-reactivity exists between mammalian and Yangtze alligator BAFF. PMID:26116474

  8. Morphogenesis and patterning of the phallus and cloaca in the American alligator, alligator mississippiensis.

    PubMed

    Gredler, Marissa L; Seifert, Ashley W; Cohn, Martin J

    2015-01-01

    In most animals, reproduction by internal fertilization is facilitated by an intromittent organ, such as the penis in amniote vertebrates. Recent progress has begun to uncover the mechanisms of mammalian external genital development; however, comparatively little is known about the development of the reptilian penis and clitoris. Here, we describe the development of the phallus and cloaca in the American alligator, Alligator mississippiensis. The embryonic precursor of the penis and clitoris is the genital tubercle, which forms by the budding of genital mesenchyme beneath the ventral body wall ectoderm, adjacent to the cloacal membrane. The cloacal lips develop from another pair of outgrowths, the lateral swellings. Early development of the alligator phallus, cloaca, and urogenital ducts generally resembles that of other reptiles, suggesting that differences in adult reptilian phallus and cloacal anatomy arise at later stages. The phallic sulcus is derived from the cloacal endoderm, indicating that the crocodilian sulcus is functionally and developmentally homologous to the mammalian urethra. Initial external genital outgrowth and patterning occur prior to temperature-dependent sex determination. Our analysis of alligator phallus and cloaca development suggests that modifications of an ancestral program of urogenital development could have generated the morphological diversity found in the external genitalia of modern amniotes. PMID:24993090

  9. Fluctuating water depths affect American alligator (Alligator mississippiensis) body condition in the Everglades, Florida, USA

    USGS Publications Warehouse

    Brandt, Laura A.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Cherkiss, Michael S.; Mazzotti, Frank J.

    2016-01-01

    Successful restoration of wetland ecosystems requires knowledge of wetland hydrologic patterns and an understanding of how those patterns affect wetland plant and animal populations.Within the Everglades, Florida, USA restoration, an applied science strategy including conceptual ecological models linking drivers to indicators is being used to organize current scientific understanding to support restoration efforts. A key driver of the ecosystem affecting the distribution and abundance of organisms is the timing, distribution, and volume of water flows that result in water depth patterns across the landscape. American alligators (Alligator mississippiensis) are one of the ecological indicators being used to assess Everglades restoration because they are a keystone species and integrate biological impacts of hydrological operations through all life stages. Alligator body condition (the relative fatness of an animal) is one of the metrics being used and targets have been set to allow us to track progress. We examined trends in alligator body condition using Fulton’s K over a 15 year period (2000–2014) at seven different wetland areas within the Everglades ecosystem, assessed patterns and trends relative to restoration targets, and related those trends to hydrologic variables. We developed a series of 17 a priori hypotheses that we tested with an information theoretic approach to identify which hydrologic factors affect alligator body condition. Alligator body condition was highest throughout the Everglades during the early 2000s and is approximately 5–10% lower now (2014). Values have varied by year, area, and hydrology. Body condition was positively correlated with range in water depth and fall water depth. Our top model was the “Current” model and included variables that describe current year hydrology (spring depth, fall depth, hydroperiod, range, interaction of range and fall depth, interaction of range and hydroperiod). Across all models, interaction

  10. Stem tissue mass density is linked to growth and resistance to a stem-boring insect in Alternanthera philoxeroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To investigate how stem anatomical structure is linked to growth and resistance to stem-boring insects in a herbaceous species, six populations of alligatorweed (Alternanthera philoxeroides) were grown in a common garden. Stem growth rate (GR) of A. philoxeroides and pupation rate as an estimate of ...

  11. Developing an Alternanthera mosaic virus vector for efficient clonging of Whitefly cDNA RNAi to screen gene function

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternanthera mosaic virus (AltMV; genus Potexvirus) is distinguished from the type member of the genus, Potato virus X by features of viral movement and variation within triple gene block protein 1 (TGB1). AltMV TGB1 variants TGB1L88 and TGB1P88 confer strong and weak silencing suppression, respect...

  12. Selective interaction between Chloroplast B ATPase and TGB1 retards severe symptoms caused by Alternanthera mosaic virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The multifunctional triple gene block protein 1 (TGB1) of the Potexvirus Alternanthera mosaic virus (AltMV) has been reported to have silencing suppressor, cell-to-cell movement, and helicase functions. Yeast two hybrid screening using an Arabidopsis thaliana cDNA library with TGB1 as bait, and co-p...

  13. Variations in hepatic biomarkers in American alligators (Alligator mississippiensis) from three sites in Florida, USA.

    PubMed

    Gunderson, Mark P; Pickett, Melissa A; Martin, Justin T; Hulse, Elizabeth J; Smith, Spenser S; Smith, Levi A; Campbell, Rachel M; Lowers, Russell H; Boggs, Ashley S P; Guillette, Louis J

    2016-07-01

    Sub-individual biomarkers are sub-lethal biological responses commonly used in the assessment of wildlife exposure to environmental contaminants. In this study, we examined the activity of glutathione-s-transferase (GST) and lactate dehydrogenase (LDH), and metallothionein (MT) concentrations among captive-raised alligator hatchlings, wild-caught juveniles, and wild-caught adults. Juveniles and adults were collected from three locations in Florida (USA) with varying degrees of contamination (i.e. Lake Apopka (organochlorine polluted site), Merritt Island National Wildlife Refuge (NWR) (metal polluted site), and Lake Woodruff NWR (reference site)). We examined whether changes in the response of these three biomarkers were age and sex dependent or reflected site-specific variations of environmental contaminants. Juvenile alligators from Merritt Island NWR had higher MT concentrations and lower GST activity compared to those from the other two sites. This outcome was consistent with higher metal pollution at this location. Sexually dimorphic patterns of MT and GST (F > M) were observed in juvenile alligators from all sites, although this pattern was not observed in adults. GST activity was lower in captive-raised alligators from Lake Apopka and Merritt Island NWR as compared to animals from Lake Woodruff NWR, suggesting a possible developmental modulator at these sites. No clear patterns were observed in LDH activity. We concluded that GST and MT demonstrate age and sex specific patterns in the alligators inhabiting these study sites and that the observed variation among sites could be due to differences in contaminant exposure. PMID:27111470

  14. Umbilical scarring in hatchling American alligators

    USGS Publications Warehouse

    Wiebe, J.J.; Sepulveda, M.S.; Buckland, J.E.; Anderson, S.R.; Gross, T.S.

    2004-01-01

    Umbilical scarring is the presence of excess scar tissue deposited between abdominal dermal layers at the site of yolk sac absorption in hatchling American alligators (Alligator mississippiensis). The presence of this dermal condition plays a key evaluatory role in the overall quality and subsequent value for various commercial leather products. Despite the prevalent nature of this condition, currently the industry has no standardized protocols for its quantification. The objectives of this study were to examine the relationship between hatchling weight and age and incidence of umbilical scarring and to develop a quantifiable and reproducible technique to measure this dermal condition in hatchling American alligators. Thirty eggs from each of nine clutches were incubated in two separate incubators at different facilities and hatchling umbilical scarring was measured at 2 and 10 days of age using digital calipers. Umbilical area was calculated by multiplying umbilical length times umbilical width. There was a significant effect of both age and clutch on umbilical area (overall decline of 64%) by 10 days post-hatch. However, only five of the nine clutches utilized expressed a noticeable decline in the size of this dermal condition (range 67-74%). We had hypothesized that larger hatchlings would have larger umbilical areas and a slower rate of improvement in this condition during the first few days post-hatch. The differences in umbilical area and percent decline with age across clutches, however, were not associated with differences in initial hatchling weights. Within clutches and time periods, hatchling weight had no significant effect on the size and/or rate of decline of this condition. ?? 2004 Published by Elsevier B.V.

  15. Habitat Suitability Index Models: American Alligator

    USGS Publications Warehouse

    Newsom, John D.; Joanen, Ted; Howard, Rebecca J.

    1987-01-01

    A review and synthesis of existing information were used to develop a model for evaluating American alligator habitat quality. The model is applicable in marshes along the northern Gulf of Mexico. It is scaled to produce an index between 0 (unsuitable habitat) and 1.0 (optimal habitat). Habitat suitability index models are designed for use with the Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service. Guidelines for model application and techniques for measuring model variables are described.

  16. WILDLIFE - ALLIGATOR BEGINS TO CROSS KENNEDY PARKWAY

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Harold O'Connor, manager of the Merritt Island Wildlife Refuge, watches a 10-foot-long alligator inch its way toward a busy highway at the Kennedy Space Center. O'Connor, aided by assistant Jerome Carroll, not shown, guided the large gator to safety in a nearby pond, several miles south of the Vehicle Assembly Building, in background. The Apollo 12 astronauts will be launched no earlier than November 14, 1969, from the Kennedy Space Center on the Nation's second manned lunar landing mission.

  17. American Alligator Research on the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Lowers, Russell H.

    2010-01-01

    This slide presentation reviews the research conducted at the Kennedy Space Center on the American Alligator. The objectives of the research were to establish life history baseline at the Kennedy Space Center and at the Merit Island National Wildlife Reserve (MINWR). Some of the factors that were examined are: nesting success, movement patterns, and population structure. Another objective was to determine the overall health of the alligator population, by analyzing blood and tissue chemistry, and urine analysis. A third objective was to compare alligators at KSC/MINWR to the statewide population. Some of the results are shown in charts and graphs.

  18. Genomics for Weed Science

    PubMed Central

    Horvath, David

    2010-01-01

    Numerous genomic-based studies have provided insight to the physiological and evolutionary processes involved in developmental and environmental processes of model plants such as arabidopsis and rice. However, far fewer efforts have been attempted to use genomic resources to study physiological and evolutionary processes of weedy plants. Genomics-based tools such as extensive EST databases and microarrays have been developed for a limited number of weedy species, although application of information and resources developed for model plants and crops are possible and have been exploited. These tools have just begun to provide insights into the response of these weeds to herbivore and pathogen attack, survival of extreme environmental conditions, and interaction with crops. The potential of these tools to illuminate mechanisms controlling the traits that allow weeds to invade novel habitats, survive extreme environments, and that make weeds difficult to eradicate have potential for both improving crops and developing novel methods to control weeds. PMID:20808523

  19. Weeds of the South

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because there is no comprehensive weed identification manual for the southeastern U.S.A., a book was compiled to include accepted nomenclature, synonyms, descriptions, life history, special identifying characteristics, habitat preference, toxicity information, distribution maps, grass collar region ...

  20. Influence of collection time on hematologic and immune markers in the American alligator (Alligator mississippiensis).

    PubMed

    Finger, John W; Williams, Robert J; Hamilton, Matthew T; Elsey, Ruth M; Oppenheimer, Victor A; Holladay, Steven D; Gogal, Robert M

    2015-01-01

    Crocodilians are important keystone species and indicators of environmental health. Much remains unknown, however regarding utility of field-collected crocodilian blood samples for ecologic assessments. Field sampling sites are also often distant to analysis centers, necessitating development of new techniques and panels of assays that will yield environmentally relevant data. Stability and viability of hematological and immunological indices have been of particular interest for linking ecosystem health to biomarkers in resident species. In this study, we investigated the effect of time at analysis post-blood sampling at 4 and 24 hr on a panel of potential biomarkers in alligator blood. Our results suggest alligator blood samples can be reliably evaluated for both hematologic and immunologic profile 24 hr after sampling. PMID:25560415

  1. Morphology and histochemistry of juvenile male American alligator (Alligator mississippiensis) phallus.

    PubMed

    Moore, Brandon C; Mathavan, Ketan; Guillette, Louis J

    2012-02-01

    Phalli of male crocodilians transfer sperm to female cloaca during sexual intercourse, resulting in internal fertilization. For over a century there have been scientific descriptions of crocodilian phallus morphologies; however, little work has presented detailed cellular-level analyses of these structures. Here we present a histological investigation of the complex functional anatomy of the juvenile male American alligator phallus, including fibrous and vascular erectile structures, a variety of secretory epithelium morphologies, and observed immune cells. Using 3D reconstruction software, we show the shape and location of vascular erectile tissues within the phallus. Histochemical staining detected mucin-rich secretory cells in glandular epithelial cells of the phallic shaft and also of the semen-conducting ventral sulcus. Lymphoid aggregates, lymphocytes, and epithelial mucin coats suggest an active immune system in the phallus defending from both the external and intracloacal environments. These results better characterize the complexity of the alligator phallus and predict later reproductive functions during adulthood. PMID:22190479

  2. Reproductive toxins and alligator abnormalities at Lake Apopka, Florida.

    PubMed Central

    Semenza, J C; Tolbert, P E; Rubin, C H; Guillette, L J; Jackson, R J

    1997-01-01

    The alligator population at Lake Apopka in central Florida declined dramatically between 1980 and 1987. Endocrine-disrupting chemicals and specifically DDT metabolites have been implicated in the alligators' reproductive failure. The DDT metabolite hypothesis is based largely on the observation of elevated concentrations of p,p-DDE and p,p-DDD in alligator eggs obtained from Lake Apopka in 1984 and 1985. In the following commentary, we draw attention to two nematocides that are established reproductive toxins in humans, dibromochloropropane (DBCP) and ethylene dibromide (EDB), which could also have played a role in the reproductive failure observed in alligators from Lake Apopka in the early 1980s. Images Figure 1. PMID:9349835

  3. An alligator basks in the sun at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    On the bank of a levee near Schwartz Rd. at Kennedy Space Center, an alligator suns itself with a wary eye out for trespassers. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  4. ENDOCRINE DISRUPTING CONTAMINANTS AND ALLIGATOR EMBRYOS: A LESSON FROM WILDLIFE?

    EPA Science Inventory

    Many xenobiotic compounds introduced into the environment by human activity adversely affect wildlife. A number of these contaminants have been hypothesized to induce non lethal, multigenerational effects by acting as endocrine disrupting agents. One case is that of the alligator...

  5. 109. Doughton Park Recreation Area. View of alligator back and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    109. Doughton Park Recreation Area. View of alligator back and the parkway seen from bluff mountain. Looking west. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  6. Development of sympathetic cardiovascular control in embryonic, hatchling, and yearling female American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Elsey, Ruth M; Crossley, Dane A

    2013-06-01

    We used arterial tyramine injections to study development of sympathetic actions on in vivo heart rate and blood pressure in embryonic, hatching and yearling female American alligators. Tyramine is a pharmacological tool for understanding comparative and developmental sympathetic regulation of cardiovascular function, and this indirect sympathomimetic agent causes endogenous neuronal catecholamine release, increasing blood pressure and heart rate. Arterial tyramine injection in hatchling and yearling alligators caused the typical vertebrate response - rise in heart rate and blood pressure. However, in embryonic alligators, tyramine caused a substantial and immediate bradycardia at both 70% and 90% of embryonic development. This embryonic bradycardia was accompanied by hypotension, followed by a sustained hypertension similar to the hatchling and juvenile responses. Pretreatment with atropine injection (cholinergic receptor blocker) eliminated the embryonic hypotensive bradycardia, and phentolamine pretreatment (α-adrenergic receptor blocker) eliminated the embryonic hypotensive and hypertensive responses but not the bradycardia. In addition, hexamethonium pretreatment (nicotinic receptor blocker) significantly blunted embryos' bradycardic tyramine response. However, pretreatment with 6-hydroxydopamine, a neurotoxin that destroys catecholaminergic terminals, did not eliminate the embryonic bradycardia. Tyramine likely stimulated a unique embryonic response - neurotransmitter release from preganglionic nerve terminals (blocked with hexamethonium) and an acetylcholine mediated bradycardia with a secondary norepinephrine-dependent sustained hypertension. In addition, tyramine appears to stimulate sympathetic nerve terminals directly, which contributed to the overall hypertension in the embryonic, hatchling and yearling animals. Data demonstrated that humoral catecholamine control of cardiovascular function was dominant over the immature parasympathetic nervous system

  7. Transdisciplinary weed research: new leverage on challenging weed problems?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transdisciplinary Weed Research (TWR) is a promising path to more effective management of challenging weed problems. We define TWR as an integrated process of inquiry and action that addresses complex weed problems in the context of broader efforts to improve economic, environmental and social aspec...

  8. Grass and weed killer poisoning

    MedlinePlus

    Weedoff poisoning; Roundup poisoning ... Glyphosate is the poisonous ingredient in some weed killers. ... Glyphosate is in weed killers with these brand names: Roundup Bronco Glifonox Kleen-up Rodeo Weedoff Other ...

  9. Persistent Organochlorine Pesticides and their Metabolites in Alligator Livers from Lakes Apopka and Woodruff, Florida, USA

    EPA Science Inventory

    Reproductive disorders in American alligators (Alligator mississippiensis) inhabiting Lake Apopka, Florida, have been observed for several years. Such disorders are hypothesized to be caused by endocrine disrupting contaminants occurring in the Lake due to pesticide spills and ...

  10. Population status of the American alligator on the Savannah River Plant, South Carolina

    SciTech Connect

    Murphy, T.M.

    1981-04-01

    Estimates are presented of alligator numbers, size distribution, sex ratios, reproductive effort, and population trends for all major components of the entire Savannah River Plant (SRP) alligator population. Savannah River Plant operations have impacted the alligator population in many different ways. The formation of man-made reservoirs has dramatically increased the amount of aquatic habitat available to alligators and has therefore increased the carrying capacity of the SRP site for this species. The thermal alteration of aquatic habitats on the SRP has also impacted the resident alligator population. Temperature elevations of aquatic habitat to greater than 38/sup 0/C result in the loss of this habitat to alligators. Moderate thermal increases on the other hand are responded to by alligator movement. The current information available on the alligators of the SRP suggests the following future trends: low density populations distant from thermally altered areas will continue at a low density with the exception of localized increases.

  11. Ecological studies on the American alligator (Alligator mississippiensis) on the Savannah River Plant. Comprehensive Cooling Water Study: Final report

    SciTech Connect

    Seigel, R.A.; Brandt, L.A.; Knight, J.L.; Novak, S.S.

    1986-06-01

    The American alligator (Alligator mississippiensis) is the largest vertebrate of the Savannah River Plant (SRP), reaching a maximum length of 3.7 meters (12 feet) and weighing up to 175 kg (385 pounds). Currently, populations in coastal South Carolina are considered Threatened, whereas populations in inland areas (such as the SRP) are still Endangered. Because of their legal status and economic and ecological importance, it is important to determine the environmental impacts of SRP operations on the local alligator population. The major objectives under the Endangered Species Program of the Comprehensive Cooling Water Study (CCWS) were as follows: (1) document and compare the present status and distribution of alligators on the SRP to previous surveys, in order to determine long-term changes in population abundance; (2) establish baseline population and ecological parameters of the Steel Creek population so that the ecological effects of L-Reactor operations can be determined, and (3) conduct ecological research on the immediate impacts of thermal effluents on American alligators. Gladden et al., (1985) summarized data on previous population surveys, temporal changes in the Par Pond population, preliminary results of the Steel Creek surveys and Savannah River Ecology Laboratory (SREL) research on the effects of thermal effluents. This report summarizes the current status of the SRP population, presents data on the abundance, movement patterns and activity cycles of the Steel Creek population, and presents additional data on the effect of cooling water releases on alligator ecology and behavior.

  12. Unidirectional airflow in the lungs of alligators.

    PubMed

    Farmer, C G; Sanders, Kent

    2010-01-15

    The lungs of birds move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi), whereas in the lungs of mammals and presumably other vertebrates, air moves tidally into and out of terminal gas-exchange structures, which are cul-de-sacs. Unidirectional flow purportedly depends on bellowslike ventilation by air sacs and may have evolved to meet the high aerobic demands of sustained flight. Here, we show that air flows unidirectionally through parabronchi in the lungs of the American alligator, an amphibious ectotherm without air sacs, which suggests that this pattern dates back to the basal archosaurs of the Triassic and may have been present in their nondinosaur descendants (phytosaurs, aetosaurs, rauisuchians, crocodylomorphs, and pterosaurs) as well as in dinosaurs. PMID:20075253

  13. Integrated Weed Management in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds lower mint oil quality and quantity and should be managed to maximize profits. Integrated weed management includes the use of cultural practices and other methods, such as herbicides. Planting healthy mint rhizomes free of weeds, insects, nematodes, and plant pathogens, and maintaining a heal...

  14. 33 CFR 165.T05-0091 - Safety Zone; Alligator River, NC.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; Alligator River, NC... Safety Zone; Alligator River, NC. (a) Definitions. For the purposes of this section, Captain of the Port... on the waters of the Alligator River centered at (35°54′3″ N/076°00′25″ W) a position directly...

  15. Alligator physiology and life history: the importance of temperature.

    PubMed

    Lance, Valentine A

    2003-07-01

    Alligators are the most northerly distributed of the extant Crocodilia. Reproducing populations are found as far north as 35 degrees latitude in the freshwater marshes and rivers of coastal North Carolina, and as far south as 25 degrees latitude in the Florida Keys. Thus different populations are exposed to very different annual thermal cycles. Alligators stop eating when ambient temperature drops below 16 degrees C. This anorexia lasts at least 6 months at 35 degrees latitude. In southwest Louisiana alligators stop feeding in October and do not resume feeding until late March or early April. It is only during the warmer months when actively feeding that growth occurs. Even with this restricted growing season Louisiana alligators grow about 30 cm a year for the first 6 years. When alligators reach sexual maturity at about 1.85 m total length growth slows in both sexes, but is significantly slower in females than males. As a result of differences in thermal regime sexual maturity is estimated at around 18 years in North Carolina and about 10 years in Louisiana. Females lay one clutch of around 40 eggs in June, but the time of nesting is also tightly linked to temperature. In a cool spring nesting can occur as late as July 5th, and in a warm spring as early as June 5th. Immature male alligators undergo a seasonal hormonal cycle similar to fully mature breeding males, but testosterone levels differ by an order of magnitude. The number of mature females reproducing each year is rarely greater than 50%, but data on internest interval is lacking. Immature female alligators show no seasonal hormonal cycle. PMID:12855291

  16. WEEDING IN TRANSGENES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenes promise to reduce insecticide and fungicide use, but relatively little has been done to significantly reduce herbicide use through genetic engineering. Three strategies for transgene utilization are discussed which have the potential to change this: 1) improvement of weed-specific biocon...

  17. A Weed Cantilever

    ERIC Educational Resources Information Center

    Keller, Elhannan L.; Padalino, John

    1977-01-01

    Describes the Environmental Action Task activity, which may be used as a recreational game or an environmental perception experience, may be conducted indoors or out-of-doors, using weed stems (or spaghetti) and masking tape to construct a cantilever. Small groups of children work together to make the cantilever with the longest arm. Further…

  18. Weed Research in Mint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds present in peppermint and spearmint reduce mint oil yield and quality. Flumioxazin combinations with clomazone and pendimethalin applied to dormant peppermint controlled prickly lettuce and flixweed without significant injury to the crop. Low rates of flumioxazin and sulfentrazone applied imm...

  19. Controlling Landscape Weeds.

    ERIC Educational Resources Information Center

    Nuss, James Robert, Jr.

    This agriculture extension service publication from Pennsylvania State University discusses the control of common grass and broadleaf weeds through the use of mulches and herbicides. The section on mulches discusses the different types of mulching materials, their advantages and disadvantages, herbicide-mulch combinations, and lists source of…

  20. Biotechnology in weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biotechnology can be used to enhance the management of weeds in several ways. Crops have been made resistant to herbicides by inserting transgenes that impart herbicide resistance into the plant genome. Glyphosate and glufosinate-resistant crops are commercialized in North America and crops made res...

  1. Weed Identification and Control in Vegetable Crops.

    ERIC Educational Resources Information Center

    Ferretti, Peter A., Comp.

    This agriculture extension service publication from Pennsylvania State University examines weed control and identification in vegetable crops. Contents include: (1) Types of weeds; (2) Reducing losses caused by weeds, general control methods and home garden weed control; (3) How herbicides are used; (4) Specific weeds in vegetable plantings; and…

  2. INTEGRATED WEED CONTROL IN MAIZE.

    PubMed

    Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

    2015-01-01

    Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach. PMID:27145588

  3. Estimating sighting proportions of American alligator nests during helicopter survey

    USGS Publications Warehouse

    Rice, Kenneth G.; Percival, H. Franklin; Woodward, Allan R.

    2000-01-01

    Proportions of American alligator (Alligator mississippiensis) nests sighted during aerial survey in Florida were estimated based upon multiple surveys by different observers. We compared sighting proportions across habitats, nesting seasons, and observer experience levels. The mean sighting proportion across all habitats and years was 0.736 (SE=0.024). Survey counts corrected by the mean sighting proportion reliably predicted total nest counts (7?2=0.933). Sighting proportions did not differ by habitat type (P=0.668) or year P=0.328). Experienced observers detected a greater proportion of nests (P<0.0001) than did either less experienced or inexperienced observers. Reliable estimates of nest abundance can be derived from aerial counts of alligator nests when corrected by the appropriate sighting proportion.

  4. The alligator gut microbiome and implications for archosaur symbioses

    PubMed Central

    Keenan, Sarah W.; Engel, Annette Summers; Elsey, Ruth M.

    2013-01-01

    Among vertebrate gastrointestinal microbiome studies, complete representation of taxa is limited, particularly among reptiles. Here, we provide evidence for previously unrecognized host-microbiome associations along the gastrointestinal tract from the American alligator, a crown archosaur with shared ancestry to extinct taxa, including dinosaurs. Microbiome compositional variations reveal that the digestive system consists of multiple, longitudinally heterogeneous microbiomes that strongly correlate to specific gastrointestinal tract organs, regardless of rearing histories or feeding status. A core alligator gut microbiome comprised of Fusobacteria, but depleted in Bacteroidetes and Proteobacteria common to mammalians, is compositionally unique from other vertebrate gut microbiomes, including other reptiles, fish, and herbivorous and carnivorous mammals. As such, modern alligator gut microbiomes advance our understanding of archosaur gut microbiome evolution, particularly if conserved host ecology has retained archosaur-specific symbioses over geologic time. PMID:24096888

  5. Spatial arrangements affect suppression of invasive Alternanthera philoxeroides by native Hemarthria compressa

    NASA Astrophysics Data System (ADS)

    Liao, Jianxiong; Tao, Min; Jiang, Mingxi

    2014-08-01

    It has been hypothesized that differences in spatial arrangements change the relative frequency of intra- and interspecific encounters between plant species. Manipulating spatial arrangement may play a role in invasive plant suppression when native species are used as competitors against introduced species. In this study, a replacement series experiment was performed to investigate the effects of intraspecifically random and aggregated spatial arrangements on interactions between the native plant Hemarthria compressa and the invasive plant Alternanthera philoxeroides, to test the possibility and effectiveness of H. compressa in suppressing A. philoxeroides. When both species were planted in intraspecifically random spatial patterns, H. compressa had a competitive advantage over A. philoxeroides at relative densities of 2:2 and 3:1. However, aggregation increased the strength, and therefore the cost, of intraspecific competition in H. compressa, resulting in lower biomass production, which reduced its effectiveness as an interspecific competitor. As the relative density of H. compressa in mixtures decreased, plants allocated more biomass to belowground parts, but fewer interspecific encounters lowered its inhibitory effects on A. philoxeroides. The results not only confirm that the frequency of conspecific and heterospecific encounters can influence competitive outcomes, but also suggest that a reduction in the degree of spatial aggregation in H. compressa and an increase in its relative densities may be essential to increase the suppression of A. philoxeroides.

  6. Phytoremediation of heavy metals by Alternanthera bettzickiana: Growth and physiological response.

    PubMed

    Tauqeer, Hafiz Muhammad; Ali, Shafaqat; Rizwan, Muhammad; Ali, Qasim; Saeed, Rashid; Iftikhar, Usman; Ahmad, Rehan; Farid, Mujahid; Abbasi, Ghulam Hassan

    2016-04-01

    The present study was aimed to evaluate the morphological, physiological and biochemical responses of Alternanthera Bettzickiana (Regel) G. Nicholson plant subjected to different levels of cadmium (Cd) and lead (Pb) (0, 0.5, 1.0 and 2.0 mM) stress. A. bettzickiana was able to accumulate Cd and Pb in different plant parts and total uptake of both metals was higher in shoots than roots. Plant growth, biomass and photosynthetic pigments increased with increasing metal concentrations, up to 1.0 mM, in soil and then decreased with higher metal levels. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) increased under lower metal levels (0.5 and 1.0 mM) while decreased at higher metal levels (2.0 mM). Leaf and root electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents decreased at lower metal levels (≤1.0 mM) while increased at higher levels. The present study clearly signifies the potential of A. bettzickiana plant towards Cd and Pb tolerance and accumulation especially at lower metal levels. PMID:26748375

  7. An urban Northeastern United States alligator bite.

    PubMed

    Shepherd, Suzanne Moore; Shoff, William H

    2014-05-01

    Individuals who live and work in the Southeastern coastal range of the 3 US crocodilian carnivores, American alligators, American crocodiles, and caiman, understand the risks of reptile-human encounters. Individuals who live in other parts of the country maybe exposed through contact with exotic pets at private homes, small menageries, or petting zoos or from escaped or abandoned animals. During these encounters, individuals may be severely injured.Emergency medical services, law enforcement, and animal welfare workers in nonhabitat areas are usually not trained in the handling and safe removal of injured individuals from the scene when the reptile is present. The emergency management of large crocodilian injuries is similar to that of other major trauma; however, providers also must take into consideration the significant crush component potentially inflicted by the tremendous bite power and shaking inflicting during attacks by these large reptiles, appropriate antibiotic coverage for less common organisms that inhabit their mouths, and management of possible psychological distress, including posttraumatic stress disorder produced by such an unusual attack. Emergency physicians should support the development of a readily available national database of scientifically collect information on attacks to inform appropriate care and support efforts to explore responsible measures that the USDA Animal and Plant Health Inspection Service and other appropriate local, state, and federal agencies can take to ensure ethical and biologically sustainable management of our large reptiles, which also helps to ensure the safety of the public. PMID:24332253

  8. Potential molecular wires and molecular alligator clips

    NASA Astrophysics Data System (ADS)

    Schumm, Jeffry S.; Pearson, Darren L.; Jones, LeRoy, II; Hara, Ryuichiro; Tour, James M.

    1996-12-01

    The synthesis of oligo(2-ethylphenylene-ethynylene)s, oligo(2-(0957-4484/7/4/023/img1-ethylheptyl)phenylene-ethynylene)s, and oligo(3-ethylthiophene-ethynylene)s is described via an iterative divergent convergent approach. Synthesized were the monomer, dimer, tetramer, octamer and 16-mer of the oligo(3-ethylthiophene-ethynylene)s and oligo(2-0957-4484/7/4/023/img1-ethylheptyl)phenylene-ethynylene)s. The 16-mers are 100 Å and 128 Å long, respectively. At each stage in the iteration, the length of the framework doubles. Only three sets of reaction conditions are needed for the entire iterative synthetic sequence; an iodination, a protodesilylation, and a Pd/Cu-catalyzed cross coupling. The oligomers were characterized spectroscopically and by mass spectrometry. The optical properties are presented which show the stage of optical absorbance saturation. The size exclusion chromatography values for the number average weights, relative to polystyrene, illustrate the tremendous differences in the hydrodynamic volume of these rigid rod oligomers versus the random coils of polystyrene. These differences become quite apparent at the octamer stage. The preparation of thiol-protected end groups is described. These may serve as molecular alligator clips for adhesion to gold surfaces. These oligomers may act as molecular wires in molecular electronic devices and they also serve as useful models for understanding related bulk polymers.

  9. Alligator osteoderms: mechanical behavior and hierarchical structure.

    PubMed

    Chen, Irene H; Yang, Wen; Meyers, Marc A

    2014-02-01

    Osteoderms are bony scutes embedded underneath the dermal layers of the skin acting as a protection of the alligator (Archosauria: Crocodylia) internal organs and tissues. Additionally, these scutes function as an aid in temperature regulation. The scutes are inter-linked by fibrous connective tissue. They have properties similar to bone and thus have the necessary toughness to provide protection against predators. The scutes consist of hydroxyapatite and have a porosity of approximately 12%. They have a disc-like morphology with a ridge along the middle of the plate, called the keel; the outer perimeter of the disc has depressions, grooves, and jagged edges which anchor the collagen and act as sutures. Computerized tomography reveals the pattern of elongated pores, which emanate from the keel in a radial pattern. Micro-indentation measurements along the cross-section show a zigzag behavior due to the porosity. Compression results indicate that the axial direction is the strongest (UTS ~67 MPa) and toughest (11 MJ/m(3)); this is the orientation in which they undergo the largest external compression forces from predator teeth. Toughening mechanisms are identified through observation of the damage progression and interpreted in mechanistic terms. They are: flattening of pores, microcrack opening, and microcrack growth and coalescence. Collagen plays an essential role in toughening and plasticity by providing bridges that impede the opening of the cracks and prevent their growth. PMID:24411399

  10. Morphological and molecular characterization of Ortleppascaris sinensis sp. nov. (Nematoda: Ascaridoidea) from the Chinese alligator Alligator sinensis.

    PubMed

    Zhao, J H; Wang, S S; Tu, G J; Zhou, Y K; Wu, X B

    2016-05-01

    A new nematode species, Ortleppascaris sinensis sp. nov. (Ascaridoidea), is described from specimens found in the stomach and intestine of the Chinese alligator Alligator sinensis Fauvel, 1879 (Crocodilian: Alligatoridae) in the National Nature Reserve of Chinese Alligator (Chinese Crocodile Lake) in Anhui Province, China. This is the first description of O. sinensis sp. nov. in both China and this crocodile host, increasing its distribution in South Asia as well as expanding the number of helminths known to infect this crocodile. The detailed description of O. sinensis sp. nov., based on light and scanning electron microscopic examination, provides new taxonomic data for this species, and we also report sequences of the internal transcribed spacers (ITS), small subunit DNA segments (18S) and the cytochrome oxidase I (COI) gene. PMID:25882968

  11. Invasive Weed Management Is Site-Specific Weed Management.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management in crops and invasive weed management in natural lands and rangelands appear to be unrelated research areas but there are many connections in the research problems, approaches and solutions. An obvious link is technology. The technology of precision agriculture - GPS, ...

  12. Estimating trends in alligator populations from nightlight survey data

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, F.J.; Dorazio, R.M.; Rice, K.G.; Cherkiss, M.; Jeffery, B.

    2011-01-01

    Nightlight surveys are commonly used to evaluate status and trends of crocodilian populations, but imperfect detection caused by survey- and location-specific factors makes it difficult to draw population inferences accurately from uncorrected data. We used a two-stage hierarchical model comprising population abundance and detection probability to examine recent abundance trends of American alligators (Alligator mississippiensis) in subareas of Everglades wetlands in Florida using nightlight survey data. During 2001-2008, there were declining trends in abundance of small and/or medium sized animals in a majority of subareas, whereas abundance of large sized animals had either demonstrated an increased or unclear trend. For small and large sized class animals, estimated detection probability declined as water depth increased. Detection probability of small animals was much lower than for larger size classes. The declining trend of smaller alligators may reflect a natural population response to the fluctuating environment of Everglades wetlands under modified hydrology. It may have negative implications for the future of alligator populations in this region, particularly if habitat conditions do not favor recruitment of offspring in the near term. Our study provides a foundation to improve inferences made from nightlight surveys of other crocodilian populations. ?? 2011 US Government.

  13. Estimating trends in alligator populations from nightlight survey data

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, Frank J.; Dorazio, Robert M.; Rice, Kenneth G.; Cherkiss, Michael; Jeffery, Brian

    2011-01-01

    Nightlight surveys are commonly used to evaluate status and trends of crocodilian populations, but imperfect detection caused by survey- and location-specific factors makes it difficult to draw population inferences accurately from uncorrected data. We used a two-stage hierarchical model comprising population abundance and detection probability to examine recent abundance trends of American alligators (Alligator mississippiensis) in subareas of Everglades wetlands in Florida using nightlight survey data. During 2001–2008, there were declining trends in abundance of small and/or medium sized animals in a majority of subareas, whereas abundance of large sized animals had either demonstrated an increased or unclear trend. For small and large sized class animals, estimated detection probability declined as water depth increased. Detection probability of small animals was much lower than for larger size classes. The declining trend of smaller alligators may reflect a natural population response to the fluctuating environment of Everglades wetlands under modified hydrology. It may have negative implications for the future of alligator populations in this region, particularly if habitat conditions do not favor recruitment of offspring in the near term. Our study provides a foundation to improve inferences made from nightlight surveys of other crocodilian populations.

  14. A preliminary evaluation of antihyperglycemic and analgesic activity of Alternanthera sessilis aerial parts

    PubMed Central

    2014-01-01

    Background Alternanthera sessilis is used by folk medicinal practitioners of Bangladesh for alleviation of severe pain. The objective of this study was to scientifically analyze the analgesic (non-narcotic) property of aerial parts of the plant along with antihyperglycemic activity. Methods Antihyperglycemic activity was measured by oral glucose tolerance tests. Analgesic (non-narcotic) activity was determined by observed decreases in abdominal writhings in intraperitoneally administered acetic acid-induced pain model in mice. Results Administration of methanol extract of aerial parts led to dose-dependent and significant reductions in blood glucose levels in glucose-loaded mice. At doses of 50, 100, 200 and 400 mg per kg body weight, the extract reduced blood sugar levels by 22.9, 30.7, 45.4 and 46.1%, respectively compared to control animals. By comparison, a standard antihyperglycemic drug, glibenclamide, when administered at a dose of 10 mg per kg body weight, reduced blood glucose level by 48.9%. In analgesic activity tests, the extract at the above four doses reduced the number of abdominal writhings by 27.6, 37.9, 41.4, and 44.8%, respectively. A standard analgesic drug, aspirin, reduced the number of writhings by 31.0 and 51.7%, respectively, when administered at doses of 200 and 400 mg per kg body weight. Conclusion The results validate the folk medicinal use of the plant to alleviate pain. At the same time, the antihyperglycemic activity result suggests that the plant may be a potential source for blood sugar lowering drug(s). PMID:24885344

  15. Studies on the Chitin Binding Property of Novel Cysteine-Rich Peptides from Alternanthera sessilis.

    PubMed

    Kini, Shruthi G; Nguyen, Phuong Q T; Weissbach, Sophie; Mallagaray, Alvaro; Shin, Joon; Yoon, Ho Sup; Tam, James P

    2015-11-01

    Hevein-like peptides make up a family of cysteine-rich peptides (CRPs) and play a role in plants in their defense against insects and fungal pathogens. In this study, we report the isolation and characterization of six hevein-like peptides, aSG1-G3 and aSR1-R3, collectively named altides from green and red varieties of Alternanthera sessilis, a perennial herb belonging to the Amaranthaceae family. Proteomic analysis of altides revealed they contain six cysteines (6C), seven glycines, four prolines, and a conserved chitin-binding domain (SXYGY/SXFGY). Thus far, only four 6C-hevein-like peptides have been isolated and characterized; hence, our study expands the existing library of these peptides. Nuclear magnetic resonance (NMR) study of altides showed its three disulfide bonds were arranged in a cystine knot motif. As a consequence of this disulfide arrangement, they are stable against thermal and enzymatic degradation. Gene cloning studies revealed altides contain a three-domain precursor with an endoplasmic reticulum signal peptide followed by a mature CRP domain and a short C-terminal tail. This indicates that the biosynthesis of altides is through the secretory pathway. (1)H NMR titration experiments showed that the 29-30-amino acid altides bind to chitin oligomers with dissociation constants in the micromolar range. Aromatic residues in the chitin-binding domain of altides were involved in the binding interaction. To the best of our knowledge, aSR1 is the smallest hevein-like peptide with a dissociation constant toward chitotriose comparable to those of hevein and other hevein-like peptides. Together, our study expands the existing library of 6C-hevein-like peptides and provides insights into their structure, biosynthesis, and interaction with chitin oligosaccharides. PMID:26467613

  16. Alligators and crocodiles as indicators for restoration of Everglades ecosystems

    USGS Publications Warehouse

    Mazzotti, Frank J.; Best, G. Ronnie; Brandt, Laura A.; Cherkiss, Michael S.; Jeffery, Brian M.; Rice, Kenneth G.

    2009-01-01

    Alligators and crocodiles integrate biological impacts of hydrological operations, affecting them at all life stages through three key aspects of Everglades ecology: (1) food webs, (2) diversity and productivity, and (3) freshwater flow. Responses of crocodilians are directly related to suitability of environmental conditions and hydrologic change. Correlations between biological responses and environmental conditions contribute to an understanding of species' status and trends over time. Positive or negative trends of crocodilian populations relative to hydrologic changes permit assessment of positive or negative trends in restoration. The crocodilian indicator uses monitoring parameters (performance measures) that have been shown to be both effective and efficient in tracking trends. The alligator component uses relative density (reported as an encounter rate), body condition, and occupancy rates of alligator holes; the crocodile component uses juvenile growth and hatchling survival. We hypothesize that these parameters are correlated with hydrologic conditions including depth, duration, timing, spatial extent and water quality. Salinity is a critical parameter in estuarine habitats. Assessments of parameters defined for crocodilian performance measures support these hypotheses. Alligators and crocodiles are the charismatic megafauna of the Everglades. They are both keystone and flagship species to which the public can relate. In addition, the parameters used to track trends are easy to understand. They provide answers to the following questions: How has the number of alligators or crocodiles changed? Are the animals fatter or thinner than they should be? Are the animals in the places (in terms of habitat and geography) where they should be? As surely as there is no other Everglades, no other single species defines the Everglades as does the American alligator. The Everglades is the only place in the world where both alligators and crocodiles exist. Crocodilians

  17. Concentrations of trace elements in American alligators (Alligator mississippiensis) from Florida, USA.

    PubMed

    Horai, Sawako; Itai, Takaaki; Noguchi, Takako; Yasuda, Yusuke; Adachi, Haruki; Hyobu, Yuika; Riyadi, Adi S; Boggs, Ashley S P; Lowers, Russell; Guillette, Louis J; Tanabe, Shinsuke

    2014-08-01

    Concentrations of 28 trace elements (Li, Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Tl, Hg, Pb, and Bi) in the livers of juvenile and adult American alligators inhabiting two central Florida lakes, Lake Apopka (LA), and Lake Woodruff National Wildlife Refuge (LW) and one lagoon population located in Merritt Island National Wildlife Refuge (MINWR; NASA), were determined. In juveniles from MINWR, concentrations of nine elements (Li, Fe, Ni, Sr, In, Sb, Hg, Pb and Bi) were significantly higher, whereas six elements (V, Fe, As, Sr, Hg and Bi) were elevated in adults (p<0.05) obtained from MINWR. Significant enrichment of some trace elements in adults, relative to juveniles, was observed at all three sampling areas. Specifically, Fe, Pb and Hg were significantly elevated in adults when compared to juveniles, suggesting age-dependent accumulation of these elements. Further, As, Se and Sn showed the same trend but only in animals collected from MINWR. Mean Fe concentrations in the livers of adults from LA, LW and MINWR were 1770 μg g(-1) DW, 3690 μg g(-1) DW and 5250 μg g(-1) DW, respectively. More than half of the adult specimens from LW and MINWR exhibited elevated hepatic Fe concentrations that exceed the threshold value for toxic effects in donkey, red deer and human. These results prompted us to express our concern on possible exposure and health effects in American alligators by some trace elements derived from NASA activities. PMID:24698170

  18. Weed Identification Field Training Demonstrations.

    ERIC Educational Resources Information Center

    Murdock, Edward C.; And Others

    1986-01-01

    Reviews efforts undertaken in weed identification field training sessions for agriprofessionals in South Carolina. Data over a four year period (1980-1983) revealed that participants showed significant improvement in their ability to identify weeds. Reaffirms the value of the field demonstration technique. (ML)

  19. Organic weed control in watermelons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integrated pest management (IPM) is an essential element for certified organic crop production and producers place weed control as their highest research priority within their IPM programs. The objective of these experiments was to investigate the impact of integrated organic weed control systems o...

  20. Parasitic Weeds, a Scientific Challenge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent issue of the SCI journal Pest Management Science (May, 2009) was devoted to an overview of the problem of parasitic weeds and to the research that is being done to alleviate it. These papers are from an OECD-sponsored conference entitled Managing Parasitic Weeds that recently brought the b...

  1. Chronic hypercapnic incubation increases relative organ growth and reduces blood pressure of embryonic American alligator (Alligator mississippiensis).

    PubMed

    Eme, John; Crossley, Dane A

    2015-04-01

    Reptilian nests can experience natural hypoxic and hypercapnic conditions. We incubated alligator eggs at a female-only producing temperature (30°C) in three conditions: 21% O2/0.04% CO2, 21% O2/3.5% CO2 and 21% O2/7% CO2. Alligator embryos chronically incubated in high CO2 were markedly hypotensive (blood pressure reduced by 46%) and had relatively (mass-specific) enlarged hearts (dry mass increased by 20%), lungs (dry mass increased by 17%), and kidneys (dry mass increased by 14%). This study is the first to chronically incubate reptilian eggs in hypercapnia and suggests that high CO2 alters the cardiovascular phenotype of alligator embryos (low blood pressure, relatively enlarged hearts), as well as the relative size of the organs primarily responsible for acid base balance, lungs and kidneys. The lungs and kidneys are largely non-functional during embryonic development, and the embryonic phenotype of increased relative mass may be a predictive-adaptation to metabolic or respiratory acidosis, such as during exercise or high respiratory CO2. This study demonstrates that phenotypic plasticity of alligator embryos incubated in high CO2 may result in either preferential organ growth, or maintenance of organ growth with reduced somatic growth. PMID:25499241

  2. Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis

    PubMed Central

    Hansen, Anne

    2007-01-01

    Background The nasal cavity of all vertebrates houses multiple chemosensors, either innervated by the Ist (olfactory) or the Vth (trigeminal) cranial nerve. Various types of receptor cells are present, either segregated in different compartments (e.g. in rodents) or mingled in one epithelium (e.g. fish). In addition, solitary chemosensory cells have been reported for several species. Alligators which seek their prey both above and under water have only one nasal compartment. Information about their olfactory epithelium is limited. Since alligators seem to detect both volatile and water-soluble odour cues, I tested whether different sensory cell types are present in the olfactory epithelium. Results Electron microscopy and immunocytochemistry were used to examine the sensory epithelium of the nasal cavity of the American alligator. Almost the entire nasal cavity is lined with olfactory (sensory) epithelium. Two types of olfactory sensory neurons are present. Both types bear cilia as well as microvilli at their apical endings and express the typical markers for olfactory neurons. The density of these olfactory neurons varies along the nasal cavity. In addition, solitary chemosensory cells innervated by trigeminal nerve fibres, are intermingled with olfactory sensory neurons. Solitary chemosensory cells express components of the PLC-transduction cascade found in solitary chemosensory cells in rodents. Conclusion The nasal cavity of the American alligator contains two different chemosensory systems incorporated in the same sensory epithelium: the olfactory system proper and solitary chemosensory cells. The olfactory system contains two morphological distinct types of ciliated olfactory receptor neurons. PMID:17683564

  3. Computed tomography of granulomatous pneumonia with oxalosis in an American alligator (Alligator mississippiensis) associated with Metarhizium anisopliae var anisopliae.

    PubMed

    Hall, Natalie H; Conley, Kenneth; Berry, Clifford; Farina, Lisa; Sigler, Lynne; Wellehan, James F X; Roehrl, Michael H A; Heard, Darryl

    2011-12-01

    An 18-yr-old, male, albino, American alligator (Alligator mississippiensis) was evaluated for decreased appetite and abnormal buoyancy. Computed tomography (CT) of the coelomic cavity showed multifocal mineral and soft tissue attenuating pulmonary masses consistent with pulmonary fungal granulomas. Additionally, multifocal areas of generalized, severe emphysema and pulmonary and pleural thickening were identified. The alligator was euthanized and necropsy revealed severe fungal pneumonia associated with oxalosis. Metarhizium anisopliae var. anisopliae was cultured from lung tissue and exhibited oxalate crystal formation in vitro. Crystals were identified as calcium oxalate monohydrate by X-ray powder defractometry. Fungal identification was based on morphology, including tissue sporulation, and DNA sequence analysis. This organism is typically thought of as an entomopathogen. Clinical signs of fungal pneumonia in nonavian reptiles are often inapparent until the disease is at an advanced stage, making antemortem diagnosis challenging. This case demonstrates the value of CT for pulmonary assessment and diagnosis of fungal pneumonia in the American alligator. Fungal infection with associated oxalosis should not be presumed to be aspergillosis. PMID:22204066

  4. Sex-steroid and thyroid hormone concentrations in juvenile alligators (Alligator mississippiensis) from contaminated and reference lakes in Florida, USA

    USGS Publications Warehouse

    Grain, D.A.; Guillette, L.J., Jr.; Pickford, D.B.; Percival, H.F.; Woodward, A.R.

    1998-01-01

    Sex-steroid and thyroid hormones are critical regulators of growth and reproduction in all vertebrates, and several recent studies suggest that environmental chemicals can alter circulating concentrations of these hormones. This study examines plasma concentrations of estradiol-171?? (E2), testosterone (T), triiodothyronine (T3), and thyroxine (T4) in juvenile alligators (60-140 cm total length) from two contaminated lakes and one reference lake in Florida. First, the data were analyzed by comparing hormone concentrations among males and females from the different lakes. Whereas there were no differences in plasma E2 concentrations among animals of the three lakes, male alligators from the contaminated lakes (Lake Apopka and Lake Okeechobee) had significantly lower plasma T concentrations compared 10 males from the reference take (Lake Woodruff). Concentrations of thyroid hormones also differed in animals of the three lakes, with T4 concentrations being elevated in Lake Okeechobee males compared to Lake Woodruff males. Second, the relationship between body size and hormone concentration was examined using regression analysis. Most notably for steroid hormones, no clear relationship was detected between E2 and total length in Apopka females (r2 0.09, p = 0.54) or between T and total length in Apopka males (r2 = 0.007, p = 0.75). Females from Apopka (r2 = 0.318, p = 0.09) and Okeechobee (r2 = 0.222, p = 0.09) exhibited weak correlations between T3 and total length. Males from Apopka (r2 = 0.015, p = 0.66) and Okeechobee (r2 = 0.128, p = 0.19) showed no correlation between T4 and total length. These results indicate: some of the previously reported abnormalities in steroid hormones of hatchling alligators persist, at least, through the juvenile years; steroid and thyroid hormones are related to body size in juvenile alligators from the reference lake, whereas alligators living in lakes Apopka and Okeechobee experience alterations in circulating thyroid and steroid

  5. The coat protein of Alternanthera mosaic virus is the elicitor of a temperature-sensitive systemic necrosis in Nicotiana benthamiana, and interacts with a host boron transporter protein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternanthera mosaic virus (AltMV; Potexvirus) naturally infects several ornamental plants. Differences were previously noted between systemic symptoms induced in Nicotiana benthamiana by different isolates of AltMV, and by four infectious clones derived from AltMV-SP. Virus accumulation was enhance...

  6. Insights into Alternanthera mosaic virus TGB3 functions: Interactions with Nicotiana benthamiana PsbO correlate with chloroplast vesiculation and veinal necrosis caused by TGB3 overexpression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternanthera mosaic virus (AltMV) triple gene block 3 (TGB3) protein is involved in viral movement. AltMV TGB3 subcellular localization was previously shown to be distinct from that of Potato virus X (PVX) TGB3, and a chloroplast binding domain identified; veinal necrosis and chloroplast vesiculati...

  7. Managing weeds in potato rotations without herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Managing weeds without herbicides requires an integration of methods and strategies and a change in how weeds are perceived. Weeds should be managed in a holistic, intentional and proactive manner. Successful weed management in organic systems attempts to understand the interactions between the crop...

  8. Applicator Training Manual for: Aquatic Weed Control.

    ERIC Educational Resources Information Center

    Herron, James W.

    The aquatic weeds discussed in this manual include algae, floating weeds, emersed weeds, and submerged weeds. Specific requirements for pesticide application are given for static water, limited flow, and moving water situations. Secondary effects of improper application rates and faulty application are described. Finally, techniques of limited…

  9. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  10. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  11. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  12. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  13. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  14. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  15. Weeding the School Library Media Collection.

    ERIC Educational Resources Information Center

    School Library Media Quarterly, 1984

    1984-01-01

    This document prepared by Calgary Board of Education, Calgary, Alberta, Canada, discusses a systematic approach to strengthening the library media collection. A statement of principle, what to weed, specific guides to weeding (by Dewey Decimal classification and type of material), what not to weed, procedures, and weeding follow-up are…

  16. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  17. 7 CFR 201.50 - Weed seed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Weed seed. 201.50 Section 201.50 Agriculture... REGULATIONS Purity Analysis in the Administration of the Act § 201.50 Weed seed. Seeds (including bulblets or tubers) of plants shall be considered weed seeds when recognized as weed seeds by the law or rules...

  18. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  19. 7 CFR 201.15 - Weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Weed seeds. 201.15 Section 201.15 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.15 Weed seeds. The percentage of weed seeds shall include seeds of plants considered weeds in the State into which the seed is offered for transportation...

  20. A new perspective with weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No-till cropping systems are increasing land productivity. Herbicides are a crucial tool for weed management in no-till, but weed resistance is decreasing control efficacy and increasing input costs. Producers are seeking a broader perspective with weed management. One approach is to disrupt weed...

  1. Annual Weeds, Alternative Crops for Alternative Fuel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All cropland acreage in Alabama is infested with one or more species of annual weeds. Weeds are estimated to cost producers in the state approximately 8% of their potential yield, even with the current weed control technology available. Weed management continues to be the most expensive row crop pr...

  2. Spatial and temporal variability in estuary habitat use by American alligators

    USGS Publications Warehouse

    Fujisaki, Ikuko; Hart, Kristen M.; Cherkiss, Michael S.; Mazzotti, Frank J.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Brandt, Laura A.

    2016-01-01

    Estuarine habitat occupied by Alligator mississippiensis, a primarily freshwater species, is spatially and temporally heterogeneous largely due to a salinity gradient that fluctuates. Using long-term night light survey data, we examined seasonal patterns in alligators’ habitat use by size classes in midstream and downstream estuary zones of Shark River, Everglades National Park, in southern Florida. We observed predominantly large-sized alligators (total length ≥ 1.75 m); observations of alligators in the small size classes (0.5 m ≤ total length < 1.25 m) were rare especially in the higher-salinity downstream zone. The density of alligators in the downstream zone was lower than that of the midstream zone during the dry season when salinity increases due to reduced precipitation. Conversely, the density of the large size alligators was higher in the downstream zone than in the midstream zone during the wet season, likely because of reduced salinity. We also found a significant declining trend over time in the number of alligators in the dry season, which coincides with the reported decline in alligator relative density in southern Florida freshwater wetlands. Our results indicated high adaptability of alligators to the fluctuating habitat conditions. Use of estuaries by alligators is likely driven in part by physiology and possibly by reproductive cycle, and our results supported their opportunistic use of estuary habitat and ontogenetic niche shifts.

  3. Detection of Antibodies to a Pathogenic Mycoplasma in American Alligators (Alligator mississippiensis), Broad-Nosed Caimans (Caiman latirostris), and Siamese Crocodiles (Crocodylus siamensis)

    PubMed Central

    Brown, D. R.; Schumacher, I. M.; Nogueira, M. F.; Richey, L. J.; Zacher, L. A.; Schoeb, T. R.; Vliet, K. A.; Bennett, R. A.; Jacobson, E. R.; Brown, M. B.

    2001-01-01

    An epidemic of pneumonia with fibrinous polyserositis and multifocal arthritis emerged in captive American alligators (Alligator mississippiensis) in Florida, United States, in 1995. Mycoplasma alligatoris sp. nov. was cultured from multiple organs, peripheral blood, synovial fluid, and cerebrospinal fluid of affected alligators. In a subsequent experimental inoculation study, the Henle-Koch-Evans postulates were fulfilled for M. alligatoris as the etiological agent of fatal mycoplasmosis of alligators. That finding was remarkable because mycoplasmal disease is rarely fatal in animals. An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies produced by alligators in response to M. alligatoris exposure was developed by using plasma obtained from naturally infected alligators during the original epidemic. The assay was validated by using plasma obtained during an experimental dose-response study and applied to analyze plasma obtained from captive and wild crocodilian species. The ELISA reliably detected alligator seroconversion (P < 0.05) beginning 6 weeks after inoculation. The ELISA also detected seroconversion (P < 0.05) in the relatively closely related broad-nosed caiman Caiman latirostris and the relatively distantly related Siamese crocodile Crocodylus siamensis following experimental inoculation with M. alligatoris. The ELISA may be used to monitor exposure to the lethal pathogen M. alligatoris among captive, repatriated, and wild crocodilian species. PMID:11136785

  4. Validation and use of an indirect enzyme-linked immunosorbent assay for detection of antibodies to West Nile virus in American Alligators (Alligator mississippiensis) in Florida.

    PubMed

    Jacobson, Elliott R; Johnson, April J; Hernandez, Jorge A; Tucker, Sylvia J; Dupuis, Alan P; Stevens, Robert; Carbonneau, Dwayne; Stark, Lillian

    2005-01-01

    In October 2002, West Nile virus (WNV) was identified in farmed American alligators (Alligator mississippiensis) in Florida showing clinical signs and having microscopic lesions indicative of central nervous system disease. To perform seroepidemiologic studies, an indirect enzyme-linked immunosorbent assay (ELISA) was developed to determine exposure of captive and wild alligators to WNV. To validate the test, a group of WNV-seropositive and -seronegative alligators were identified at the affected farm using hemagglutination inhibition (HAI) and the plaque reduction neutralization test (PRNT). The indirect ELISA utilized a rabbit anti-alligator immunoglobulins polyclonal antibody as the secondary antibody, and inactivated WNV-infected Vero cells were used as the coating antigen. For all samples (n=58), the results of the ELISA were consistent with the HAI and PRNT findings. Plasma was collected from 669 free-ranging alligators from 21 sites across Florida in April and October 2003. Four samples collected in April and six in October were positive for WNV antibodies using HAI, PRNT, and the indirect ELISA. This indicated that wild alligators in Florida have been exposed to WNV. These findings can be used as a baseline for future surveys. PMID:15827216

  5. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point...

  6. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point...

  7. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order...

  8. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order...

  9. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order...

  10. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order...

  11. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point...

  12. 50 CFR 23.70 - How can I trade internationally in American alligator and other crocodilian skins, parts, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... American alligator and other crocodilian skins, parts, and products? 23.70 Section 23.70 Wildlife and... in Certain Specimens § 23.70 How can I trade internationally in American alligator and other... section, crocodilian means all species of alligator, caiman, crocodile, and gavial of the order...

  13. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point...

  14. 33 CFR 334.760 - Naval Support Activity Panama City and Alligator Bayou, a tributary of St. Andrew Bay, Fla...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... City and Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. 334.760 Section... Alligator Bayou, a tributary of St. Andrew Bay, Fla.; naval restricted area. (a) The area. The waters within... the south side of the entrance to Alligator Bayou; thence directly across the entrance to a point...

  15. Survival of young American alligators on a Florida lake

    USGS Publications Warehouse

    Woodward, A.R.; Hines, T.C.; Abercrombie, C.L.; Nichols, J.D.

    1987-01-01

    A capture-recapture study was conducted on Orange Lake, Florida, from 1979 through 1984 to estimate survival rates of young in an American alligator (Alligator mississippiensis) populations. Hatchlings remained together in sibling groups (pods) for at least their 1st year and then began to disperse during their 2nd spring and summer. Mortality through mid-November of their 1st year was negligible. Jolly-Seber (JS) survival estimates of hatchlings for 6 and 12 months were 76 and 41%, respectively. The 2-year JS estimate for the 1980 cohort was 8%. Minimum-Known-Alive (MKA) survival values were 72 and 46% of JS estimates for 6 months and 1 year of age. Survival during the 2nd 6 months of life (spring-summer) tended to be lower than survival during the 1st 6 months (fall-winter).

  16. A new alligator-clip compound for molecular electronics

    NASA Astrophysics Data System (ADS)

    Jacob, Timo; Blanco, Mario; Goddard, William A.

    2004-06-01

    We used the B3LYP flavor of density functional calculations to study new alligator-clip compounds for molecular electronics with platinum electrodes. First, with commonly used S-based linkage molecule 3-methyl-1,2-dithiolane (MDTL) we find that after chemisorption on Pt(1 1 1) the most stable structure is ring-opened with a binding energy of 32.44 kcal/mol. Among several alternative alligator-clip compounds we find that P-based molecules lead to much higher binding energies. For the ring-closed structure of 3-methyl-1,2-diphospholane (MDPL) a binding energy of 47.72 kcal/mol was calculated and even 54.88 kcal/mol for the ring-opened molecule. Thus, MDPL provides a more stable link to the metal surface and might increase the conductance.

  17. Differential limb scaling in the american alligator (Alligator mississippiensis) and its implications for archosaur locomotor evolution.

    PubMed

    Livingston, Victoria J; Bonnan, Matthew F; Elsey, Ruth M; Sandrik, Jennifer L; Wilhite, D Ray

    2009-06-01

    Bipedalism evolved multiple times within archosaurs, and relatively shorter forelimbs characterize both crocodyliforms and nonavian dinosaurs. Analysis of a comprehensive ontogenetic sequence of specimens (embryo to adult) of the sauropodomorph Massospondylus has shown that bipedal limb proportions result from negative forelimb allometry. We ask, is negative forelimb allometry a pattern basal to archosaurs, amplified in certain taxa to produce bipedalism? Given the phylogenetic position of extant crocodylians and their relatively shorter forelimb, we tested the hypothesis that prevalent negative forelimb allometry is present in Alligator mississippiensis from a sample of wild specimens from embryonic to adult sizes. Long bone lengths (humerus, radius, ulna, femur, tibia, fibula, third metapodials) were measured with their epiphyseal cartilage intact at all sizes. Our results show an overall isometric pattern for most elements regressed on femur length, humerus length, or total limb length. However, negative allometry was prevalent for the ulna, and the third metapodials scale with positive allometry embryonically. These data suggest that the general forelimb proportions in relation to the hindlimb do not change significantly with increasing size in A. mississippiensis. The negative allometry of the ulna and embryonicaly positive allometry of the third metapodials appears to be related to maintaining the functional integrity of the limbs. We show that this pattern is different from that of the sauropodomorph Massospondylus, and we suggest that if bipedalism in archosaurs is tied, in part, to negative forearm allometry, it was either secondarily lost through isometric scaling, or never developed in the ancestor of A. mississippiensis. PMID:19462445

  18. Mathematical models for growth in alligator (Alligator mississippiensis) embryos developing at different incubation temperatures.

    PubMed Central

    Bardsley, W G; Ackerman, R A; Bukhari, N A; Deeming, D C; Ferguson, M W

    1995-01-01

    A variety of model-based (growth models) and model-free (cubic splines, exponentials) equations were fitted using weighted-nonlinear least squares regression to embryonic growth data from Alligator mississippiensis eggs incubated at 30 and 33 degrees C. Goodness of fit was estimated using a chi 2 on the sum of squared, weighted residuals, and run and sign tests on the residuals. One of the growth models used (Preece & Baines, 1978) was found to be superior to the classical growth models (exponential, monomolecular, logistic, Gompertz, von Bertalanffy) and gave an adequate fit to all longitudinal measures taken from the embryonic body and embryonic mass. However, measurements taken from the head could not be fitted by growth models but were adequately fitted by weighted least squares cubic splines. Data for the stage of development were best fitted by a sum of 2 exponentials with a transition point. Comparison of the maximum growth rates and parameter values, indicated that the growth data at 30 degrees C could be scaled to 33 degrees C to multiplying the time by a scaling factor of 1.2. This is equivalent to a Q10 of about 1.86 or, after solving the Arrhenius equation, an E++ of 46.9 kJmol-1. This may be interpreted as indicating a common rate-limiting step in development at the 2 temperatures. PMID:7591979

  19. Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites.

    PubMed

    Tellez, Marisa; Merchant, Mark

    2015-01-01

    Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment. PMID:26555363

  20. 78 FR 57480 - Safety Zone; 2013 Annual Islamorada Swim for Alligator Lighthouse, Atlantic Ocean; Islamorada, FL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ...) 366-9826. SUPPLEMENTARY INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; 2013 Annual Islamorada Swim for Alligator... Islamorada, Florida, during the 2013 Annual Islamorada Swim for Alligator Lighthouse on September 21,...

  1. WILDLIFE - ALLIGATOR STROLLS FROM TURN BASIN TO LC 39 PRESS SITE GRANDSTAND

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A 12-foot alligator worked his way up from the turn basin at Press Site 39 to the grandstand seats. The toothy reptile was later wrangled by wildlife trappers who relocated him to a less populated area on KSC. The alligator is one of approximately 4,000 on KSC/Merritt Island National Wildlife Refuge.

  2. PLASMA STEROID CONCENTRATIONS IN RELATION TO SIZE AND AGE IN JUVENILE ALLIGATORS FROM TWO FLORIDA LAKES.

    EPA Science Inventory

    Previous studies have reported a number of physiological differences among juvenile alligators from two well-studied populations (Lake Apopka and Lake Woodruff) in north central Florida. These studies obtained alligators of similar size from each lake under the assumption that th...

  3. Biomonitoring Heavy Metal Pollution Using an Aquatic Apex Predator, the American Alligator, and Its Parasites

    PubMed Central

    Tellez, Marisa; Merchant, Mark

    2015-01-01

    Monitoring the bioaccumulation of chemical elements within various organismal tissues has become a useful tool to survey current or chronic levels of heavy metal exposure within an environment. In this study, we compared the bioaccumulations of As, Cd, Cu, Fe, Pb, Se, and Zn between the American alligator, Alligator mississippiensis, and its parasites in order to establish their use as bioindicators of heavy metal pollution. Concomitant with these results, we were interested to determine if parasites were more sensitive bioindicators of heavy metals relative to alligators. We found parasites collectively accumulated higher levels of As, Cu, Se, and Zn in comparison to their alligator hosts, whereas Fe, Cd, and Pb concentrations were higher in alligators. Interestingly, Fe levels were significantly greater in intestinal trematodes than their alligator hosts when analyzed independently from other parasitic taxa. Further analyses showed alligator intestinal trematodes concentrated As, Cu, Fe, Se, and Zn at significantly higher levels than intestinal nematodes and parasites from other organs. However, pentastomids also employed the role as a good biomagnifier of As. Interestingly, parasitic abundance decreased as levels of As increased. Stomach and intestinal nematodes were the poorest bioaccumulators of metals, yet stomach nematodes showed their ability to concentrate Pb at orders of magnitude higher in comparison to other parasites. Conclusively, we suggest that parasites, particularly intestinal trematodes, are superior biomagnifiers of As, Cu, Se, and Zn, whereas alligators are likely good biological indicators of Fe, Cd, and Pb levels within the environment. PMID:26555363

  4. The growth response of Alternanthera philoxeroides in a simulated post-combustion emission with ultrahigh [CO2] and acidic pollutants.

    PubMed

    Xu, Cheng-Yuan; Griffin, Kevin L; Blazier, John C; Craig, Elizabeth C; Gilbert, Dominique S; Sritrairat, Sanpisa; Anderson, O Roger; Castaldi, Marco J; Beaumont, Larry

    2009-07-01

    Although post-combustion emissions from power plants are a major source of air pollution, they contain excess CO2 that could be used to fertilize commercial greenhouses and stimulate plant growth. We addressed the combined effects of ultrahigh [CO2] and acidic pollutants in flue gas on the growth of Alternanthera philoxeroides. When acidic pollutants were excluded, the biomass yield of A. philoxeroides saturated near 2000 micromol mol(-1) [CO2] with doubled biomass accumulation relative to the ambient control. The growth enhancement was maintained at 5000 micromol mol(-1) [CO2], but declined when [CO2] rose above 1%, in association with a strong photosynthetic inhibition. Although acidic components (SO2 and NO2) significantly offset the CO2 enhancement, the aboveground yield increased considerably when the concentration of pollutants was moderate (200 times dilution). Our results indicate that using excess CO2 from the power plant emissions to optimize growth in commercial green house could be viable. PMID:19269074

  5. Green synthesis of silver nanoparticles using Alternanthera dentata leaf extract at room temperature and their antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Kumar, Deenadayalan Ashok; Palanichamy, V.; Roopan, Selvaraj Mohana

    2014-06-01

    A green rapid biogenic synthesis of silver nanoparticles AgNPs using Alternanthera dentata (A. dentata) aqueous extract was demonstrated in this present study. The formation of silver nanoparticles was confirmed by Surface Plasmon Resonance (SPR) at 430 nm using UV-visible spectrophotometer. The reduction of silver ions to silver nanoparticles by A. dentata extract was completed within 10 min. Synthesized nanoparticles were characterized using UV-visible spectroscopy; Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy (TEM). The extracellular silver nanoparticles synthesis by aqueous leaf extract demonstrates rapid, simple and inexpensive method comparable to chemical and microbial methods. The colloidal solution of silver nanoparticles were found to exhibit antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia and, Enterococcus faecalis.

  6. Can Global Weed Assemblages Be Used to Predict Future Weeds?

    PubMed Central

    Morin, Louise; Paini, Dean R.; Randall, Roderick P.

    2013-01-01

    Predicting which plant taxa are more likely to become weeds in a region presents significant challenges to both researchers and government agencies. Often it is done in a qualitative or semi-quantitative way. In this study, we explored the potential of using the quantitative self-organising map (SOM) approach to analyse global weed assemblages and estimate likelihoods of plant taxa becoming weeds before and after they have been moved to a new region. The SOM approach examines plant taxa associations by analysing where a taxon is recorded as a weed and what other taxa are recorded as weeds in those regions. The dataset analysed was extracted from a pre-existing, extensive worldwide database of plant taxa recorded as weeds or other related status and, following reformatting, included 187 regions and 6690 plant taxa. To assess the value of the SOM approach we selected Australia as a case study. We found that the key and most important limitation in using such analytical approach lies with the dataset used. The classification of a taxon as a weed in the literature is not often based on actual data that document the economic, environmental and/or social impact of the taxon, but mostly based on human perceptions that the taxon is troublesome or simply not wanted in a particular situation. The adoption of consistent and objective criteria that incorporate a standardized approach for impact assessment of plant taxa will be necessary to develop a new global database suitable to make predictions regarding weediness using methods like SOM. It may however, be more realistic to opt for a classification system that focuses on the invasive characteristics of plant taxa without any inference to impacts, which to be defined would require some level of research to avoid bias from human perceptions and value systems. PMID:23393591

  7. Cultural practices in cotton (Gossypium hirsutum) affect weed seed production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Billions of dollars are lost annually due to weeds or weed control, but weeds persist. Successful weed management systems must reduce weed populations. The objectives of this research were to 1) determine if cotton row spacing has an impact on weed growth and seed production and 2) evaluate the infl...

  8. Sweet corn hybrid tolerance to weed competition under three weed management levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly all commercial sweet corn fields contain weeds that escaped management and often suffer yield loss due to weed competition. Field trials were conducted from 2009 to 2011 near Prosser, WA and Urbana, IL to evaluate weed response and tolerance of four sweet corn hybrids to three levels of weed...

  9. Sweet Corn Hybrid Tolerance to Weed Competition under Three Weed Management Levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nearly all commercial sweet corn fields contain weeds that escaped management and often suffer yield loss due to weed competition. Field trials were conducted from 2009 to 2011 near Prosser, WA and Urbana, IL to evaluate weed response and tolerance of four sweet corn hybrids to three levels of weed...

  10. Gastric nematode diversity between estuarine and inland freshwater populations of the American alligator (Alligator mississippiensis, daudin 1802), and the prediction of intermediate hosts

    PubMed Central

    Tellez, Marisa; Nifong, James

    2014-01-01

    We examined the variation of stomach nematode intensity and species richness of Alligator mississippiensis from coastal estuarine and inland freshwater habitats in Florida and Georgia, and integrated prey content data to predict possible intermediate hosts. Nematode parasitism within inland freshwater inhabiting populations was found to have a higher intensity and species richness than those inhabiting coastal estuarine systems. This pattern potentially correlates with the difference and diversity of prey available between inland freshwater and coastal estuarine habitats. Increased consumption of a diverse array of prey was also correlated with increased nematode intensity in larger alligators. Parasitic nematodes Dujardinascaris waltoni, Brevimulticaecum tenuicolle, Ortleppascaris antipini, Goezia sp., and Contracaecum sp. were present in alligators from both habitat types. Dujardinascaris waltoni, B. tenuicolle, and O. antipini had a significantly higher abundance among inland inhabiting alligators than hosts from estuarine populations. Our findings also suggest that host specific nematode parasites of alligators may have evolved to infect multiple intermediate hosts, particularly fishes, crabs, and turtles, perhaps in response to the opportunistic predatory behaviors of alligators. PMID:25426417

  11. A weed control program for establishing lesquerella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broad spectrum weed control is essential for successful lesquerella [Lesquerella fendleri (Gray) Wats., Brassicaceae] production. Weeds must be controlled during establishment and throughout the growing season. Lesquerella seedlings grow slowly following germination and emergence, and cannot compe...

  12. Weed control options for transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As interest in sweet onion production has grown in Oklahoma and Arkansas, so has the realization that uncontrolled weeds can result in a total loss of marketable onion production. Although mechanical weed control can successfully control weeds between rows, producers need reliable methods for contro...

  13. Managing weeds with a population dynamics approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    No-till cropping systems are increasing land productivity. A critical aspect of no-till is controlling weeds. Herbicides are a crucial tool for weed management, but weed resistance is decreasing control efficacy and increasing input costs. Scientists and producers are seeking a broader perspectiv...

  14. Cover Crop Effects on Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds are often the most common and costly pests in vegetable production, especially in organic production systems. Weeds that germinate during cover cropping and produce seeds will increase the weed seedbank and may increase production costs. This chapter discusses the effect of cultural practices ...

  15. Weed control efficacy with Racer (ammonium nonanoate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems. Agricultural weed control costs the U.S. economy more than the cost of insect and disease control combined. Organic vegetable producers have many challenges since their weed control tools are mostly limited to cultur...

  16. Dry years decrease abundance of American alligators in the Florida Everglades

    USGS Publications Warehouse

    Waddle, J. Hardin; Brandt, Laura A.; Jeffery, Brian M.; Mazzotti, Frank J.

    2015-01-01

    The Everglades has been greatly reduced and is threatened by land use change and altered hydrology. The Comprehensive Everglades Restoration Plan calls for monitoring and assessment of key ecosystem attributes, one of which is abundance of American alligators. We examined 10 years of alligator night spotlight counts from Arthur R. Marshall Loxahatchee National Wildlife Refuge along two canals and in the interior marsh to determine trends and how dry years affect alligator abundance. Alligators showed population response to hydrologic conditions. In particular, there were declines in abundance after dry years followed by an apparent recovery in abundance in subsequent years. Increases in abundance were lower in the marsh than L-40 Canal. In addition, there was evidence that intensity of dry events affected population dynamics with greater declines observed in years with drier conditions. Results revealed that overall population of alligators increased from 2004 to 2013, but that increases varied by survey route. These results demonstrate that dry years cause a decline in alligator abundance proportional to the intensity of the dry event, and that it is important to make a distinction between canals and marsh when measuring alligator response to hydrology.

  17. What's a Weed? Knowledge, Attitude and Behaviour of Park Visitors about Weeds.

    PubMed

    Ansong, Michael; Pickering, Catherine

    2015-01-01

    Weeds are a major threat to biodiversity globally degrading natural areas of high conservation value. But what are our attitudes about weeds and their management including weeds in national parks? Do we know what a weed is? Do we consider weeds a problem? Do we support their management? Are we unintentionally spreading weeds in parks? To answer these questions, we surveyed visitors entering a large popular national park near the city of Brisbane, Australia. Park visitors were knowledgeable about weeds; with >75% correctly defining weeds as 'plants that grow where they are not wanted'. About 10% of the visitors, however, provided their own sophisticated definitions. This capacity to define weeds did not vary with people's age, sex or level of education. We constructed a scale measuring visitors' overall concern about weeds in parks using the responses to ten Likert scale statements. Over 85% of visitors were concerned about weeds with older visitors, hikers, and those who could correctly define weeds more concerned than their counterparts. The majority think visitors unintentionally introduce seeds into parks, with many (63%) having found seeds on their own clothing. However, over a third disposed of these seeds in ways that could facilitate weed spread. Therefore, although most visitors were knowledgeable and concerned about weeds, and support their control, there is a clear need for more effective communication regarding the risk of visitors unintentionally dispersing weed seeds in parks. PMID:26252004

  18. What’s a Weed? Knowledge, Attitude and Behaviour of Park Visitors about Weeds

    PubMed Central

    Ansong, Michael; Pickering, Catherine

    2015-01-01

    Weeds are a major threat to biodiversity globally degrading natural areas of high conservation value. But what are our attitudes about weeds and their management including weeds in national parks? Do we know what a weed is? Do we consider weeds a problem? Do we support their management? Are we unintentionally spreading weeds in parks? To answer these questions, we surveyed visitors entering a large popular national park near the city of Brisbane, Australia. Park visitors were knowledgeable about weeds; with >75% correctly defining weeds as ‘plants that grow where they are not wanted’. About 10% of the visitors, however, provided their own sophisticated definitions. This capacity to define weeds did not vary with people’s age, sex or level of education. We constructed a scale measuring visitors’ overall concern about weeds in parks using the responses to ten Likert scale statements. Over 85% of visitors were concerned about weeds with older visitors, hikers, and those who could correctly define weeds more concerned than their counterparts. The majority think visitors unintentionally introduce seeds into parks, with many (63%) having found seeds on their own clothing. However, over a third disposed of these seeds in ways that could facilitate weed spread. Therefore, although most visitors were knowledgeable and concerned about weeds, and support their control, there is a clear need for more effective communication regarding the risk of visitors unintentionally dispersing weed seeds in parks. PMID:26252004

  19. Using weeds to fight wastes

    SciTech Connect

    1992-10-01

    Researchers at Los Alamos National Laboratory and New Mexico State University have discovered that jimson weed and wild tomato plants can remove the toxic wastes in wastewater associated with the production of trinitrotoluene (TNT). According to Wolfgang F. Mueller of New Mexico State, tissue-cultured cells of jimson weed rapidly absorb and break down toxic and carcinogenic elements in {open_quotes}pink water,{close_quotes} a by-product of the manufacture of TNT. Mueller and his colleagues have found similar results with the wild tomato plant.

  20. Possible generational effects of habitat degradation on alligator reproduction

    USGS Publications Warehouse

    Fujisaki, Ikuko; Rice, K.G.; Woodward, A.R.; Percival, H.F.

    2007-01-01

    Population decline of the American alligator (Alligator mississippiensis) was observed in Lake Apopka in central Florida, USA, in the early 1980s. This decline was thought to result from adult mortality and nest failure caused by anthropogenic increases in sediment loads, nutrients, and contaminants. Reproductive impairment also was reported. Extensive restoration of marshes associated with Lake Apopka has been conducted, as well as some limited restoration measures on the lake. Monitoring by the Florida Fish and Wildlife Conservation Commission (FFWCC) has indicated that the adult alligator population began increasing in the early 1990s. We expected that the previously reported high proportion of complete nest failure (??0) during the 1980s may have decreased. We collected clutches from alligator nests in Lake Apopka from 1983 to 2003 and from 5 reference areas from 1988 to 1991, and we artificially incubated them. We used a Bayesian framework with Gibbs sampler of Markov chain Monte Carlo simulation to analyze ??0. Estimated ??0was consistently higher in Lake Apopka compared with reference areas, and the difference in ??0 ranged from 0.19 to 0.56. We conducted change point analysis to identify and test the significance of the change point in ??0in Lake Apopka between 1983 and 2003, indicating the point of reproductive recovery. The estimated Bayes factor strongly supported the single change point hypothesis against the no change point hypothesis. The major downward shift in ??0 probably occurred in the mid-1990s, approximately a generation after the major population decline in the 1980s. Furthermore, estimated ??0 values after the change point (0.21) were comparable with those of reference areas (0.07-0.31). These results combined with the monitoring by FFWCC seem to suggest that anthropogenic habitat degradation caused reproductive impairment of adult females and decreases in ??0 occurred with the sexual maturity of a new generation of breeding females. Long

  1. Traumatic Amputation of Finger From an Alligator Snapping Turtle Bite.

    PubMed

    Johnson, Robert D; Nielsen, Cynthia L

    2016-06-01

    Legend states that the alligator snapping turtle (Macrochelys temminckii) should be handled with extreme caution as it has jaw strength powerful enough to bite a wooden broomstick in half. Tales of bite injuries from what is the largest freshwater turtle in North America exist anecdotally, yet there are few descriptions of medical encounters for such. The risk of infection from reptilian bites to the hand in an aquatic environment warrants thorough antibiotic treatment in conjunction with hand surgery consultation. We present the first case report of a near total amputation of an index finger in an adolescent boy who had been bitten by a wild "gator snapper." PMID:27116923

  2. Comparison of metabolic substrates in alligators and several birds of prey.

    PubMed

    Sweazea, Karen L; McMurtry, John P; Elsey, Ruth M; Redig, Patrick; Braun, Eldon J

    2014-08-01

    On average, avian blood glucose concentrations are 1.5-2 times those of mammals of similar mass and high concentrations of insulin are required to lower blood glucose. Whereas considerable data exist for granivorous species, few data are available for plasma metabolic substrate and glucoregulatory hormone concentrations for carnivorous birds and alligators. Birds and mammals with carnivorous diets have higher metabolic rates than animals consuming diets with less protein whereas alligators have low metabolic rates. Therefore, the present study was designed to compare substrate and glucoregulatory hormone concentrations in several birds of prey and a phylogenetically close relative of birds, the alligator. The hypothesis was that the combination of carnivorous diets and high metabolic rates favored the evolution of greater protein and fatty acid utilization leading to insulin resistance and high plasma glucose concentrations in carnivorous birds. In contrast, it was hypothesized that alligators would have low substrate utilization attributable to a low metabolic rate. Fasting plasma substrate and glucoregulatory hormone concentrations were compared for bald eagles (Haliaeetus leucocephalus), great horned owls (Bubo virginianus), red-tailed hawks (Buteo jamaicensis), and American alligators (Alligator mississippiensis). Avian species had high circulating β-hydroxybutyrate (10-21 mg/dl) compared to alligators (2.81 ± 0.16 mg/dl). In mammals high concentrations of this byproduct of fatty acid utilization are correlated with insulin resistance. Fasting glucose and insulin concentrations were positively correlated in eagles whereas no relationship was found between these variables for owls, hawks or alligators. Additionally, β-hydroxybutyrate concentrations were low in alligators. Similar to carnivorous mammals, ingestion of a high protein diet may have favored the utilization of fatty acids and protein for energy thereby promoting the development of insulin

  3. Genomics and Weeds: A Synthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomics can be used to solve many problems associated with the management of weeds. New target sites for herbicides have been discovered through functional genomic approaches to determine gene function. Modes of action of herbicides can be clarified or discovered by transcriptome analysis. Under...

  4. Weed Biocontrol in Landscape Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  5. CLASSICAL BIOLOGICAL CONTROL OF WEEDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical biological control of weeds is an important tool for managing invasive alien plants that have become too widespread to control by conventional methods. It involves the discovery and release of naturally occurring species of natural enemies (insects, mites or pathogens) to control a pest (...

  6. Weed biocontrol in landscape restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed biological control programs in natural areas are often undertaken with the goal of restoring native plant communities and/or ecosystem services to a pre-invasion level. These objectives may be achieved in some areas with biological control alone; however, in other sites integration of biologica...

  7. ALTERED HISTOLOGY OF THE THYMUS AND SPLEEN IN CONTAMINANT-EXPOSED JUVENILE AMERICAN ALLIGATORS

    EPA Science Inventory

    Morphological difference in spleen and thymus are closely related to functional immune differences. Hormonal regulation of the immune system has been demonstrated in reptilian splenic and thymic tissue. Spleens and thymus were obtained from juvenile alligators at two reference si...

  8. Concentrations of contaminants in muscle of the American alligator in Florida

    SciTech Connect

    Delany, M.F.; Bell, J.U.; Sundlof, S.F.

    1988-01-01

    Samples of tail muscle from 32 American alligators (Alligator mississippiensis) in Florida were analyzed for contaminant concentrations to provide preliminary information on the potential public health hazard of meat consumption. Detectable levels were found for eight metals; copper, zinc, iron, chromium, mercury, lead, cadmium and arsenic. Mean residue was highest for mercury (geometric mean = 0.61 ppm). DDE, DDD, DDT, dieldrin, heptachlor epoxide, lindane, and PCB's were found. Mean residue concentrations were compared by lake. Alligators appeared to be suitable monitors of environmental pollution. Concentrations of contaminants found in these animals probably pose little threat to public health. However, recommendations must await analysis of larger sample sizes and information on amount and frequency of meat consumption. Alligators killed for human consumption should continue to be monitored for contaminant residues.

  9. Ground-Based Sensing System for Weed Mapping in Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A ground-based weed mapping system was developed to measure weed intensity and distribution in a cotton field. The weed mapping system includes WeedSeeker® PhD600 sensor modules to indicate the presence of weeds between rows, a GPS receiver to provide spatial information, and a data acquisition and ...

  10. Preemergence herbicides affect critical period of weed control in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective weed control systems must eliminate emerged weeds as well as account for subsequent weed emergence. Two common questions associated with herbicide control are: 1) how long can weeds compete with a crop for resources before yield is reduced and 2) when do weeds that emerge late in the seaso...

  11. Molecular cloning of the estrogen and progesterone receptors of the American alligator.

    PubMed

    Katsu, Yoshinao; Bermudez, Dieldrich S; Braun, Edward L; Helbing, Caren; Miyagawa, Shinichi; Gunderson, Mark P; Kohno, Satomi; Bryan, Teresa A; Guillette, Louis J; Iguchi, Taisen

    2004-03-01

    Steroid hormones perform many essential roles in vertebrates during embryonic development, reproduction, growth, water balance, and responses to stress. The estrogens are essential for normal reproductive activity in female and male vertebrates and appear to have direct actions during sex determination in some vertebrates. To begin to understand the molecular mechanisms of estrogen action in alligators, we have isolated cDNAs encoding the estrogen receptors (ER) from the ovary. Degenerate PCR primers specific to ER were designed and used to amplify alligator ovary RNA. Two different DNA fragments (ERalpha and ERbeta) were obtained and the full-length alligator ERalpha cDNA was obtained using 5' and 3' RACE. The inferred amino acid sequence of alligator ERalpha (aERalpha) was very similar to the chicken ERalpha (91% identity), although phylogenetic analyses suggested profound differences in the rate of sequence evolution for vertebrate ER sequences. We also isolated partial DNA fragments encoding ERbeta and the progesterone receptor (PR) of the alligator, both of which show strong sequence similarities to avian ERbeta and PR. We examined the expression levels of these three steroid receptors (ERalpha, ERbeta, and PR) in the ovary of juvenile alligators and observed detectable levels of all three receptors. Quantitative RT-PCR showed that gonadal ERalpha transcript levels in juvenile alligators decreased after E2 treatment whereas ERbeta and PR transcripts were not changed. These results provide tools that will allow future studies examining the regulation and ontogenic expression of steroid receptors in alligators and expand our knowledge of vertebrate steroid receptor evolution. PMID:14980803

  12. Scale-Dependent Habitat Selection and Size-Based Dominance in Adult Male American Alligators.

    PubMed

    Strickland, Bradley A; Vilella, Francisco J; Belant, Jerrold L

    2016-01-01

    Habitat selection is an active behavioral process that may vary across spatial and temporal scales. Animals choose an area of primary utilization (i.e., home range) then make decisions focused on resource needs within patches. Dominance may affect the spatial distribution of conspecifics and concomitant habitat selection. Size-dependent social dominance hierarchies have been documented in captive alligators, but evidence is lacking from wild populations. We studied habitat selection for adult male American alligators (Alligator mississippiensis; n = 17) on the Pearl River in central Mississippi, USA, to test whether habitat selection was scale-dependent and individual resource selectivity was a function of conspecific body size. We used K-select analysis to quantify selection at the home range scale and patches within the home range to determine selection congruency and important habitat variables. In addition, we used linear models to determine if body size was related to selection patterns and strengths. Our results indicated habitat selection of adult male alligators was a scale-dependent process. Alligators demonstrated greater overall selection for habitat variables at the patch level and less at the home range level, suggesting resources may not be limited when selecting a home range for animals in our study area. Further, diurnal habitat selection patterns may depend on thermoregulatory needs. There was no relationship between resource selection or home range size and body size, suggesting size-dependent dominance hierarchies may not have influenced alligator resource selection or space use in our sample. Though apparent habitat suitability and low alligator density did not manifest in an observed dominance hierarchy, we hypothesize that a change in either could increase intraspecific interactions, facilitating a dominance hierarchy. Due to the broad and diverse ecological roles of alligators, understanding the factors that influence their social dominance

  13. WILDLIFE - ALLIGATOR STRADDLES TWO PARKING SPACES IN FRONT OF OFFICE TRAILER

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Double-parked, an angry alligator straddles two parking spaces outside an office trailer at NASA's Launch Complex 17. Hank Curtin of Pan Am watches from a safe perch as John Tanner gets ready to wrap a rope around the snout of the 10-foot, 9-inch beast. It's all in a day's work for Tanner, who has a contract with the state of Florida to remove nuisance alligators.

  14. The future for weed control and technology.

    PubMed

    Shaner, Dale L; Beckie, Hugh J

    2014-09-01

    This review is both a retrospective (what have we missed?) and prospective (where are we going?) examination of weed control and technology, particularly as it applies to herbicide-resistant weed management (RWM). Major obstacles to RWM are discussed, including lack of diversity in weed management, unwillingness of many weed researchers to conduct real integrated weed management research or growers to accept recommendations, influence or role of agrichemical marketing and governmental policy and lack of multidisciplinary research. We then look ahead to new technologies that are needed for future weed control in general and RWM in particular, in areas such as non-chemical and chemical weed management, novel herbicides, site-specific weed management, drones for monitoring large areas, wider application of 'omics' and simulation model development. Finally, we discuss implementation strategies for integrated weed management to achieve RWM, development of RWM for developing countries, a new classification of herbicides based on mode of metabolism to facilitate greater stewardship and greater global exchange of information to focus efforts on areas that maximize progress in weed control and RWM. There is little doubt that new or emerging technologies will provide novel tools for RMW in the future, but will they arrive in time? PMID:24339388

  15. Relationship between body condition of American alligators and water depth in the Everglades, Florida

    USGS Publications Warehouse

    Fujisaki, Ikuko; Rice, Kenneth G.; Pearlstine, Leonard G.; Mazzotti, Frank J.

    2009-01-01

    Feeding opportunities of American alligators (Alligator mississippiensis) in freshwater wetlands in south Florida are closely linked to hydrologic conditions. In the Everglades, seasonally and annually fluctuating surface water levels affect populations of aquatic organisms that alligators consume. Since prey becomes more concentrated when water depth decreases, we hypothesized an inverse relationship between body condition and water depth in the Everglades. On average, condition of adult alligators in the dry season was significantly higher than in the wet season, but this was not the case for juveniles/subadults. The correlation between body condition and measured water depth at capture locations was weak; however, there was a significant negative correlation between the condition and predicted water depth prior to capture for all animals except for spring juveniles/subadults which had a weak positive condition-water depth relationship. Overall, a relatively strong inverse correlation occurred at 10-49 days prior to the capture day, suggesting that current body condition of alligators may depend on feeding opportunities during that period. Fitted regression of body condition on water depth (mean depth of 10 days when condition-water depth correlation was greatest) resulted in a significantly negative slope, except for spring adult females and spring juveniles/subadults for which slopes were not significantly different from zero. Our results imply that water management practices may be critical for alligators in the Everglades since water depth can affect animal condition in a relatively short period of time.

  16. Use of alligator hole abundance and occupancy rate as indicators for restoration of a human-altered wetland

    USGS Publications Warehouse

    Fujisaki, Ikuko; Mazzotti, Frank J.; Hart, Kristen M.; Rice, Kenneth G.; Ogurcak, Danielle; Rochford, Michael; Jeffery, Brian M.; Brandt, Laura A.; Cherkiss, Michael S.

    2012-01-01

    Use of indicator species as a measure of ecosystem conditions is an established science application in environmental management. Because of its role in shaping wetland systems, the American alligator (Alligator mississippiensis) is one of the ecological indicators for wetland restoration in south Florida, USA. We conducted landscape-level aerial surveys of alligator holes in two different habitats in a wetland where anthropogenic modification of surface hydrology has altered the natural system. Alligator holes were scarcer in an area where modified hydrology caused draining and frequent dry-downs compared to another area that maintains a functional wetland system. Lower abundance of alligator holes indicates lack of alligator activities, lower overall species diversity, and lack of dry-season aquatic refugia for other organisms. The occupancy rate of alligator holes was lower than the current restoration target for the Everglades, and was variable by size class with large size-class alligators predominantly occupying alligator holes. This may indicate unequal size-class distribution, different habitat selection by size classes, or possibly a lack of recruitment. Our study provides pre-restoration baseline information about one indicator species for the Everglades. Success of the restoration can be assessed via effective synthesis of information derived by collective research efforts on the entire suite of selected ecological indicators.

  17. TEMPORAL AND SPATIAL VARIATION IN PLASMA THYROXINE (T4) CONCENTRATIONS IN JUVENILE ALLIGATORS COLLECTED FROM LAKE OKEECHOBEE AND THE NORTHERN EVERGLADES, FLORIDA, USA

    EPA Science Inventory

    We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site...

  18. The coat protein of Alternanthera mosaic virus is the elicitor of a temperature-sensitive systemic necrosis in Nicotiana benthamiana, and interacts with a host boron transporter protein

    SciTech Connect

    Lim, Hyoun-Sub; Nam, Jiryun; Seo, Eun-Young; Nam, Moon; Vaira, Anna Maria; Bae, Hanhong; Jang, Chan-Yong; Lee, Cheol Ho; Kim, Hong Gi; Roh, Mark; Hammond, John

    2014-03-15

    Different isolates of Alternanthera mosaic virus (AltMV; Potexvirus), including four infectious clones derived from AltMV-SP, induce distinct systemic symptoms in Nicotiana benthamiana. Virus accumulation was enhanced at 15 °C compared to 25 °C; severe clone AltMV 3-7 induced systemic necrosis (SN) and plant death at 15 °C. No interaction with potexvirus resistance gene Rx was detected, although SN was ablated by silencing of SGT1, as for other cases of potexvirus-induced necrosis. Substitution of AltMV 3-7 coat protein (CP{sub SP}) with that from AltMV-Po (CP{sub Po}) eliminated SN at 15 °C, and ameliorated symptoms in Alternanthera dentata and soybean. Substitution of only two residues from CP{sub Po} [either MN(13,14)ID or LA(76,77)IS] efficiently ablated SN in N. benthamiana. CP{sub SP} but not CP{sub Po} interacted with Arabidopsis boron transporter protein AtBOR1 by yeast two-hybrid assay; N. benthamiana homolog NbBOR1 interacted more strongly with CP{sub SP} than CP{sub Po} in bimolecular fluorescence complementation, and may affect recognition of CP as an elicitor of SN. - Highlights: • Alternanthera mosaic virus CP is an elicitor of systemic necrosis in N. benthamiana. • Virus-induced systemic necrosis is enhanced at 15 °C compared to 25 °C. • Induction of systemic necrosis is dependent on as few as two CP amino acid residues. • These residues are at subunit interfaces within the same turn of the virion helix. • Inducer/non-inducer CPs interact differentially with a boron transporter protein.

  19. Integration of herbicides with manual weeding for controlling the weeds in rice under saline environment.

    PubMed

    Hakim, M A; Juraimi, Abdul Shukor; Hanafi, M M; Rafii, Mohd Y; Ismail, Mohd Razi; Karim, S M Rezaul; Kausar, H

    2015-11-01

    The pot experiment was conducted to select appropriate integrated weed management method in rice under different salinity levels (0, 4 and 8 dS m(-1)). All the parameters including rice and weed measured were significantly influenced by weed control treatments at all salinity levels. Treatments including weed-free condition, Pretilachlor @0.375 kg ai ha(-1) + hand weeding, Propanil + Thiobencarb @ 0.9 kg ai ha(-1) and 1.8 kg ai ha(-1)+ hand weeding performed better under all salinity levels. Pretilachlor @ 0.375 kg ai ha(-1) with one round of hand weeding and propanil + thiobencarb 0.9 kg ai ha(-1) + 1.8 kg ai ha(-1) with one round of hand weeding were comparable to weed-free yields, and were superior to other treatments under salinity condition. Considering all the parameters, pretilachlor @ 0.375 kg ai ha(-1) + one round of hand weeding (at 65 DAT), propanil + thiobencarb 0.9 kg ai ha(-1) +1.8 kg ai ha(-1) + one round of hand weeding (at 65 DAT) gave the most effective control of weeds in rice under saline environments. PMID:26688966

  20. WEED COMMUNITY COMPOSTION IN RESPONSE TO ORGANIC AND CONVENTIONAL WEED CONTROL PRACTICES IN A CALIFORNIA VINEYARD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integrated weed management (IWM) employs multiple tactics to control weed infestations, and can be useful in reducing problematic weeds. IWM in California vineyards typically involves the integration of post-emergence herbicides and pre-emergence herbicides, with less emphasis on incorporation of no...

  1. Weeding Is Not Just for Gardeners: A Case Study on Weeding a Reference Collection

    ERIC Educational Resources Information Center

    Lee, Marta

    2009-01-01

    Weeding a reference collection can be time consuming, a thankless job, and an endless task. It is a dusty job and can add to the librarian's workload. Weeding the collection can add to its currency and usability; plus it removes outdated materials. Periodically weeding allows librarians to remember what is in the collection and what can be removed…

  2. Alligator rivers analogue project an OECD/NEA international project

    SciTech Connect

    Duerden, P.; Airey, P.; Pescatore, C.

    1994-12-31

    The Koongarra uranium deposit in the Alligator Rivers Region of the Northern Territory of Australia was studied as a natural analogue of the far field behaviour of high level waste repositories following groundwater ingress. A number of mathematical modelling approaches were developed for processes as diverse as groundwater transport, host rock weathering, radionuclide sorption, evolution of the uranium dispersion fan and the distribution of uranium series nuclides between mineral assemblages in weathered host rock. Some of these models are relevant to performance assessment at the level of individual processes and subsystem performance. Through the project, new insights into the application of the natural analogue approach to the assessment of potential waste repository sites were obtained.

  3. Isolation and characterization of sulfite oxidase from Alligator mississipiensis

    SciTech Connect

    Robbins, A.; Neame, P.J.; Barber, M.J. )

    1991-03-11

    Sulfite oxidase has been isolated from fresh alligator liver using ammonium sulfate and acetone fractionation, DEAE chromatography and FPLC on Mono Q. The enzyme is dimeric and exhibits a subunit M. Wt. of approximately 58 kDa, larger than that of chicken SO. EPR spectroscopy of the partially-reduced enzyme revealed a single Mo(V) species while visible spectroscopy revealed the presence of cytochrome b{sub 557}. Maximal activities were obtained at pH 8 and 9, respectively. K{sub m}'s for SO{sub 3}{sup 2 {minus}}, cyt. c and Fe(CN){sub 6}{sup 3 {minus}} were 23.5 uM, 2.9 uM and 8.0 uM, respectively. Sequencing of peptides obtained by endoprotease K digestion indicated regions of extensive sequence similarity to chicken and rat enzymes in both heme and Mo-pterin domains. Regions of sequence dissimilarity were also found.

  4. The importance of weeds in ethnopharmacology.

    PubMed

    Stepp, J R; Moerman, D E

    2001-04-01

    Tropical primary forest is often considered to be the most important habitat for traditional peoples to gather medicinal plants. However, the role of weeds, commonly found in disturbed areas, in traditional medicinal floras has been overlooked. Data are presented showing the significant representation of weeds in the medicinal floras of the Highland Maya in Chiapas, Mexico and in the medicinal flora of Native North Americans as a whole. The frequency with which weeds appear in these pharmacopoeias is significantly larger (P<0.0001) than what would be predicted by the frequency of weed species in general. Explanations based on human ecology and biochemical ecology are presented. PMID:11282438

  5. Nutrient absorbtion of weeds in maize.

    PubMed

    Lehoczky, E; Kismányoky, A; Nagy, P; Németh, T

    2008-01-01

    Our study was carried out in Hungary at Keszthely, in 2007. The effect of different cultivation methods: no-till drill, disk tillage, conventional tillage (ploughing) and five increasing N doses were studied on the weediness. The bi-factorial trial was arranged in split plot design with four replications. Crop rotation: winter wheat-winter wheat-maize-maize. The seeding of maize was 23rd of April in 2007. The weed survey was made with Balázs-Ujvárosi coenological method on the 17th of May. In the experiment were found 21 weed species. We collected all plants of every weed species by plots. The sample area was 1 m2. Furthermore five maize plants per plot were sampled on the 22nd of May. Maize was at 3-4 leaves stage. For reason of competition studies no herbicides were applied on sampling sites. The aerial parts of weeds and maize plants were collected, and the fresh and dry matter weight was measured. We analyzed in detail, the occurrence of weed species, and the biomass production of weeds in comparison with maize. The effect of different cultivation methods markedly demonstrated the weed cover, the number of perennial and annual weeds and the number of occurring weed species. PMID:19226848

  6. A Chinese alligator in heliox: formant frequencies in a crocodilian

    PubMed Central

    Reber, Stephan A.; Nishimura, Takeshi; Janisch, Judith; Robertson, Mark; Fitch, W. Tecumseh

    2015-01-01

    ABSTRACT Crocodilians are among the most vocal non-avian reptiles. Adults of both sexes produce loud vocalizations known as ‘bellows’ year round, with the highest rate during the mating season. Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behaviour in crocodilians. In mammals and birds, a common mechanism for producing honest acoustic signals of body size is via formant frequencies (vocal tract resonances). To our knowledge, formants have to date never been documented in any non-avian reptile, and formants do not seem to play a role in the vocalizations of anurans. We tested for formants in crocodilian vocalizations by using playbacks to induce a female Chinese alligator (Alligator sinensis) to bellow in an airtight chamber. During vocalizations, the animal inhaled either normal air or a helium/oxygen mixture (heliox) in which the velocity of sound is increased. Although heliox allows normal respiration, it alters the formant distribution of the sound spectrum. An acoustic analysis of the calls showed that the source signal components remained constant under both conditions, but an upward shift of high-energy frequency bands was observed in heliox. We conclude that these frequency bands represent formants. We suggest that crocodilian vocalizations could thus provide an acoustic indication of body size via formants. Because birds and crocodilians share a common ancestor with all dinosaurs, a better understanding of their vocal production systems may also provide insight into the communication of extinct Archosaurians. PMID:26246611

  7. A Chinese alligator in heliox: formant frequencies in a crocodilian.

    PubMed

    Reber, Stephan A; Nishimura, Takeshi; Janisch, Judith; Robertson, Mark; Fitch, W Tecumseh

    2015-08-01

    Crocodilians are among the most vocal non-avian reptiles. Adults of both sexes produce loud vocalizations known as 'bellows' year round, with the highest rate during the mating season. Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behaviour in crocodilians. In mammals and birds, a common mechanism for producing honest acoustic signals of body size is via formant frequencies (vocal tract resonances). To our knowledge, formants have to date never been documented in any non-avian reptile, and formants do not seem to play a role in the vocalizations of anurans. We tested for formants in crocodilian vocalizations by using playbacks to induce a female Chinese alligator (Alligator sinensis) to bellow in an airtight chamber. During vocalizations, the animal inhaled either normal air or a helium/oxygen mixture (heliox) in which the velocity of sound is increased. Although heliox allows normal respiration, it alters the formant distribution of the sound spectrum. An acoustic analysis of the calls showed that the source signal components remained constant under both conditions, but an upward shift of high-energy frequency bands was observed in heliox. We conclude that these frequency bands represent formants. We suggest that crocodilian vocalizations could thus provide an acoustic indication of body size via formants. Because birds and crocodilians share a common ancestor with all dinosaurs, a better understanding of their vocal production systems may also provide insight into the communication of extinct Archosaurians. PMID:26246611

  8. Post-hatching development of Alligator mississippiensis ovary and testis

    PubMed Central

    Moore, Brandon C.; Hamlin, Heather J.; Botteri, Nicole L.; Lawler, Ashley N.; Mathavan, Ketan K.; Guillette, Louis J.

    2009-01-01

    We investigated ovary and testis development of Alligator mississippiensis during the first five months post-hatch. To better describe follicle assembly and seminiferous cord development, we employed histochemical techniques to detect carbohydrate-rich extracellular matrix components in one-week, one-month, three-month, and five-month-old gonads. We found profound morphological changes in both ovary and testis. During this time, oogenesis progressed up to diplotene arrest and meiotic germ cells increasingly interacted with follicular cells. Concomitant with follicles becoming invested with full complements of granulosa cells, a periodic acid Schiff’s (PAS)-positive basement membrane formed. As follicles enlarged and thecal layers were observed, basement membranes and thecal compartments gained periodic acid-methionine silver (PAMS)-reactive fibers. The ovarian medulla increased first PAS- and then PAMS-reactivity as it fragmented into wide lacunae lined with low cuboidal to squamous epithelia. During this same period, testicular germ cells found along the tubule margins were observed progressing from spermatogonia to round spermatids located within the center of tubules. Accompanying this meiotic development, interstitial Leydig cell clusters become more visible and testicular capsules thickened. During the observed testis development, the thickening tunica albuginea and widening interstitial tissues showed increasing PAS- and PAMS-reactivity. We observed putative inter-sex structures in both ovary and testis. On the coelomic aspect of testes were cell clusters with germ cell morphology and at the posterior end of ovaries, we observed “medullary rests” resembling immature testis cords. We hypothesize laboratory conditions accelerated gonad maturation due to optimum conditions, including nutrients and temperature. Laboratory alligators grew more rapidly and with increased body conditions compared to previous measured, field-caught animals. Additionally, we

  9. Recurrent Water Level Fluctuation Alleviates the Effects of Submergence Stress on the Invasive Riparian Plant Alternanthera philoxeroides

    PubMed Central

    Zhang, Haijie; Wang, Renqing; Wang, Xiao; Du, Ning; Ge, Xiuli; Du, Yuanda; Liu, Jian

    2015-01-01

    Recurrent water level fluctuation and submergence of plants are common in riparian zones. Our study objectives were to test the independent and interactive effects of submergence level and fluctuation frequency on a globally important riparian invasive plant, Alternanthera philoxeroides. To this end, we conducted a greenhouse experiment, in which ramets of the plants, obtained from a wetland in China, were treated with four fluctuation frequencies (0, 3, 6, and 12 cycles over a 96-day experimental period) under three water levels (0, 10, and 30 cm). We found that effects of fluctuation frequency were non-significant, negative, and positive under water levels of 0, 10 and 30 cm, respectively. As fluctuation frequency increased, the effects of increasing water level decreased significantly. When water levels were high, A. philoxeroides allocated greater biomass to shoot production probably in order to elongate and escape from submergence. However, as fluctuation frequency increased, biomass investment in roots and leaves also increased, probably in order to maximize nutrient absorption and photosynthesis, respectively. These results suggest that water level fluctuation may alleviate the effects of submergence on A. philoxeroides. In addition, A. philoxeroides showed significant phenotypic plasticity, adjusting its functional traits, such as number of nodes and leaves per stem, as well as stem diameter and pith cavity diameter, according to recurrent water level fluctuation. We conclude that A. philoxeroides may perform better in shallow water zones under conditions of disturbance that include recurrent water level fluctuation. This ability to adapt to disturbance likely promotes its growth and invasion in disturbed habitats. PMID:26066509

  10. Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides

    PubMed Central

    You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions. PMID:27200041

  11. Propagule Pressure, Habitat Conditions and Clonal Integration Influence the Establishment and Growth of an Invasive Clonal Plant, Alternanthera philoxeroides.

    PubMed

    You, Wen-Hua; Han, Cui-Min; Fang, Long-Xiang; Du, Dao-Lin

    2016-01-01

    Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules) may affect the establishment, growth, and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments) or low (one fragment) propagule pressure was established either in bare soil (open habitat) or dense native vegetation of Jussiaea repens (vegetative habitat), with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions. PMID:27200041

  12. Phytoremediation of sulfonated Remazol Red dye and textile effluents by Alternanthera philoxeroides: An anatomical, enzymatic and pilot scale study.

    PubMed

    Rane, Niraj R; Chandanshive, Vishal V; Watharkar, Anuprita D; Khandare, Rahul V; Patil, Tejas S; Pawar, Pankaj K; Govindwar, Sanjay P

    2015-10-15

    Alternanthera philoxeroides Griseb. a macrophyte was found to degrade a highly sulfonated textile dye Remazol Red (RR) completely within 72 h at a concentration of 70 mg L(-1). An induction in the activities of azoreductase and riboflavin reductase was observed in root and stem tissues; while the activities of lignin peroxidase, laccase and DCIP reductase were induced in leaf tissues. Some enzymes namely tyrosinase, veratryl alcohol oxidase, catalase and superoxide dismutase displayed an increase in their activity in all the tissues in response of 72 h exposure to Remazol Red. There was a marginal reduction in contents of chlorophyll a (20%), chlorophyll b (5%) and carotenoids (16%) in the leaves when compared to control plants. A detailed anatomical study of the stem during uptake and treatment revealed a stepwise mechanism of dye degradation. UV-vis spectrophotometric and high performance thin layer chromatographic analyses confirmed the removal of parent dye from solution. Based on the enzymes activities and gas chromatography-mass spectroscopic analysis of degradation products, a possible pathway of phytotransformation of RR was proposed which revealed the formation of 4-(phenylamino)-1,3,5-triazin-2-ol, naphthalene-1-ol and 3-(ethylsulfonyl)phenol. Toxicity study on Devario aequipinnatus fishes showed that the anatomy of gills of fishes exposed to A. philoxeroides treated RR was largely protected. The plants were further explored for rhizofiltration experiments in a pilot scale reactor. A. philoxeroides could decolorize textile industry effluent of varying pH within 96 h of treatment which was evident from the significant reductions in the values of American dye manufacturers' institute color, chemical oxygen demand, biological oxygen demand, total dissolved and total suspended solids. PMID:26164661

  13. Thermal acclimation, mitochondrial capacities and organ metabolic profiles in a reptile (Alligator mississippiensis).

    PubMed

    Guderley, Helga; Seebacher, Frank

    2011-01-01

    Reptiles thermoregulate behaviourally, but change their preferred temperature and the optimal temperature for performance seasonally. We evaluated whether the digestive and locomotor systems of the alligator show parallel metabolic adjustments during thermal acclimation. To this end, we allowed juvenile alligators to grow under thermal conditions typical of winter and summer, providing them with seasonally appropriate basking opportunities. Although mean body temperatures of alligators in these groups differed by approximately 10°C, their growth and final anatomic status was equivalent. While hepatic mitochondria isolated from cold-acclimated alligators had higher oxidative capacities at 30°C than those from warm-acclimated alligators, the capacities did not differ at 20°C. Cold acclimation decreased maximal oxidative capacities of muscle mitochondria. For mitochondria from both organs and acclimation groups, palmitate increased oligomycin-inhibited respiration. GDP addition reduced palmitate-uncoupled rates more in liver mitochondria from warm- than cold-acclimated alligators. In muscle mitochondria, carboxyatractyloside significantly reduced palmitate-uncoupled rates. This effect was not changed by thermal acclimation. The aerobic capacity of liver, skeletal muscle and duodenum, as estimated by activities of cytochrome c oxidase (COX), increased with cold acclimation. At acclimation temperatures, the activities of COX and citrate synthase (CS) in these organs were equivalent. By measuring COX and CS in isolated mitochondria and tissue extracts, we estimated that cold acclimation did not change the mitochondrial content in liver, but increased that of muscle. The thermal compensation of growth rates and of the aerobic capacity of the locomotor and digestive systems suggests that alligators optimised metabolic processes for the seasonally altered, preferred body temperature. The precision of this compensatory response exceeds that typically shown by aquatic

  14. Chronic Ingestion of Coal Fly-Ash Contaminated Prey and Its Effects on Health and Immune Parameters in Juvenile American Alligators (Alligator mississippiensis).

    PubMed

    Finger, John W; Hamilton, Matthew T; Metts, Brian S; Glenn, Travis C; Tuberville, Tracey D

    2016-10-01

    Coal-burning power plants supply approximately 37 % of the electricity in the United States. However, incomplete combustion produces ash wastes enriched with toxic trace elements that have historically been disposed of in aquatic basins. Organisms inhabiting such habitats may accumulate these trace elements; however, studies investigating the effects on biota have been primarily restricted to shorter-lived, lower-trophic organisms. The American alligator (Alligator mississippiensis), a long-lived, top-trophic carnivore, has been observed inhabiting these basins, yet the health or immune effects of chronic exposure and possible accumulation remains unknown. In this study, we investigated how chronic dietary ingestion of prey contaminated with coal combustion wastes (CCWs) for 25 months, and subsequent accumulation of trace elements present in CCWs, affected juvenile alligator immune function and health. Alligators were assigned to one of four dietary-treatment groups including controls and those fed prey contaminated with CCWs for one, two, or three times a week. However, no effect of Dietary Treatment (p > 0.05) was observed on any immune parameter or hematological or plasma analyte we tested. Our results suggest that neither exposure to nor accumulation of low doses of CCWs had a negative effect on certain aspects of the immune and hematological system. However, future studies are required to elucidate this further. PMID:27475646

  15. Temporal profile of nerve growth factor expression in the partial central nervous system of the Yangtze alligator Alligator sinensis (Reptilia,Crocodylia) during early postnatal growth.

    PubMed

    Zheng, Lanrong; Chen, Fangfang; Wang, Renping; Zhou, Yongkang; Wu, Xiaobing

    2013-05-01

    Expression of nerve growth factor (NGF) in structures of the partial central nervous system of the Yangtze alligator, Alligator sinensis (Reptilia, Crocodylia) was examined during early postnatal growth using immunohistochemistry and Western blot assays. In animals 0-2 years of age NGF-positive cells in the cerebral cortex increased gradually in number and size, and were predominantly distributed in the molecular layer. NGF-positive cells in the midbrain showed similar increases but with predominant distribution in the ependymal layer. NGF-positive cells increased in the cerebellum between 0 and 1 years of age, with increased NGF expression being seen during the first 2 years of life mostly in the ependymal layer. NGF-positive cells were mainly found in the gray matter of the spinal cord with decreasing cell numbers, NGF expression levels being seen from 0 to 2 years and small processes without synaptic connection from 1 to 2 years. These results suggest that NGF is involved in the early postnatal growth of several structures of Yangtze alligator partial central nervous system, suggesting a possible role of NGF in the Yangtze alligator partial central nervous system. PMID:23504856

  16. Broadleaf weed control in lima beans.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Broadleaf weeds are particularly troublesome in lima beans due to the long growing season which extends beyond the period in which soil residual herbicides provide control. Weeds reduce yield and quality of lima beans, reduce harvest efficiency, and increase incidence of white mold. A study was co...

  17. Crop/weed discrimination in simulated images

    NASA Astrophysics Data System (ADS)

    Jones, G.; Gée, C.; Truchetet, F.

    2007-02-01

    In the context of site-specific weed management by vision systems, an efficient image processing for a crop/weed discrimination is required in order to quantify the Weed Infestation Rate (WIR) in an image. This paper presents a modeling of crop field in presence of different Weed Infestation Rates and a set of simulated agronomic images is used to test and validate the effectiveness of a crop/weed discrimination algorithm. For instance, an algorithm has been implemented to firstly detect the crop rows in the field by the use of a Hough Transform and secondly to detect plant areas by a region based-segmentation on binary images. This image processing has been tested on virtual cereal fields of a large field of view with perspective effects. The vegetation in the virtual field is modeled by a sowing pattern for crop plants and the weed spatial distribution is modeled by either a Poisson process or a Neyman-Scott cluster process. For each simulated image, a comparison between the initial and the detected weed infestation rate allows us to assess the accuracy of the algorithm. This comparison demonstrates an accuracy of better than 80% is possible, despite that intrarow weeds can not be detected from this spatial method.

  18. Post-directed weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and ...

  19. Software Tools for Weed Seed Germination Modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The next generation of weed seed germination models will need to account for variable soil microclimate conditions. In order to predict this microclimate environment we have developed a suite of individual tools (models) that can be used in conjunction with the next generation of weed seed germinati...

  20. Yield advances in peanut - weed control effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements in weed management are a contributing factor to advancements in peanut yield. Widespread use of vacuum planters and increased acceptance of narrow row patterns enhance weed control by lessening bareground caused by skips and promoting quick canopy closure. Cultivation was traditionall...

  1. Nutsedge ecology in plasticulture affects weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purple nutsedge and yellow nutsedge are naturalized exotic invasive weeds that are the most troublesome weeds of vegetable crops in the southeast US. Tubers are the primary means of nutsedge reproduction. Effective management strategies must suppress nutsedge tuber production. Greenhouse studies eva...

  2. Scythe (pelargonic acid) weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season-long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, and y...

  3. Preemergence weed control in watermelon - Lane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watermelon is a major vegetable crop in Oklahoma. Weed control on this crop is crucial for commercial growers particularly as labor costs increase and availability of hoeing crews decrease. Weed infested fields can be a source of pest problems including insect and disease, in addition to the obvio...

  4. When Can You Weed an Unused Book?

    ERIC Educational Resources Information Center

    Ettelt, Harold

    A study was conducted in 1988 by a community college librarian who was seeking an objective guide for weeding unused library books. It was hypothesized that a book not used in a certain number of years would never be used. At the beginning of the study, no books had ever been weeded although the library had begun acquiring books in 1969. To test…

  5. Molecular biology approaches to weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global climate change appears to be favorable for invasive weed development and spread because invasive species in general are proficient at succeeding in new environments. To worsen matters, herbicide-resistant weeds have become a severe threat in modern agricultural systems due to the extensive us...

  6. Weeding the Library Media Center Collections.

    ERIC Educational Resources Information Center

    Buckingham, Betty Jo

    These guidelines for weeding library media collections are addressed to elementary and secondary school library media centers and to community college and vocational school library resource centers in Iowa. The publication includes some philosophy about weeding, and specific guidelines are summarized in bold-faced type for ease of use. The…

  7. Weed competition and dry bean yield components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed competition can significantly reduce dry bean (Phaseolus vulgaris L.) yields and therefore the profitability for the producer. Depending on the dry bean variety produced, the yield components may be affected differently by the stress produced by weed competition. This research was conducted to ...

  8. Fire Effects on Invasive Weed Seed Germination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoring historic fire regimes is often beneficial to rangeland structure and function. However, understanding of interactions between fire and invasive weeds is limited. We designed an experiment to determine fire effects on germination of soil surface-deposited seeds of the invasive weeds Bromu...

  9. Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Barlow, R. M.; Mcdonald, R. C.

    1975-01-01

    Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

  10. Effects of egg and hatchling harvest on American alligators in Florida

    USGS Publications Warehouse

    Rice, K.G.; Percival, H.F.; Woodward, A.R.; Jennings, Michael L.

    1999-01-01

    Harvest of crocodilian eggs and young for captive rearing (ranching) has been used worldwide as an option for producing crocodilian skins and meat from wild stock. The long-term effects of harvesting a certain proportion of early age class, wild American alligators (Alligator mississippiensis) without repatriation is unknown. We removed an estimated 50% of annual production of alligators on Lakes Griffin and Jesup in central Florida over an 11-year period and monitored population levels via night-light counts. Densities of the total alligator population increased (P 0.117), and subadult (122-182 cm TL) alligators increased (P < 0.011) on harvest areas. The density of juveniles on the control area increased (P = 0.006), and the density of subadults showed some evidence of increasing (P = 0.088). No changes were detected in size distributions on the treatment areas. Nest production, as observed from aerial helicopter surveys, increased (P < 0.039) on Lake Woodruff NWR and Lake Jesup and showed some evidence of an increase on Lake Griffin (P = 0.098) during 1983-91. A 50% harvest rate of eggs or hatchlings did not adversely affect recruitment into the subadult or adult size classes.

  11. The influence of regional hydrology on nesting behavior and nest fate of the American alligator

    USGS Publications Warehouse

    Ugarte, Cristina A.; Bass, Oron L.; Nuttle, William; Mazzotti, Frank J.; Rice, Kenneth G.; Fujisaki, Ikuko; Whelan, Kevin R.T.

    2013-01-01

    Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species.

  12. American alligator digestion rate of blue crabs and its implications for stomach contents analysis

    USGS Publications Warehouse

    Nifong, James C.; Rosenblatt, Adam E.; Johnson, Nathan A.; Barichivich, William; Silliman, Brian; Heithaus, Michael R.

    2012-01-01

    Stomach contents analysis (SCA) provides a snap-shot observation of a consumer's diet. Interpretation of SCA data can be complicated by many factors, including variation in gastric residence times and digestion rates among prey taxa. Although some SCA methods are reported to efficiently remove all stomach contents, the effectiveness of these techniques has rarely been tested for large irregular shaped prey with hard exoskeletons. We used a controlled feeding trial to estimate gastric residency time and decomposition rate of a large crustacean prey item, the Blue Crab (Callinectes sapidus), which is consumed by American Alligators (Alligator mississippiensis), an abundant apex predator in coastal habitats of the southeastern United States. The decomposition rate of C. sapidus in the stomachs of A. mississippiensis followed a predictable pattern, and some crab pieces remained in stomachs for at least 14 days. We also found that certain portions of C. sapidus were prone to becoming caught within the stomach or esophagus, meaning not all crab parts are consistently recovered using gastric lavage techniques. However, because the state of decomposition of crabs was predictable, it is possible to estimate time since consumption for crabs recovered from wild alligators. This information, coupled with a detailed understanding of crab distributions and alligator movement tactics could help elucidate patterns of cross-ecosystem foraging by the American Alligator in coastal habitats

  13. Effect of alligator pepper (Zingiberaceae aframomum melegueta) on first trimester pregnancy in Sprague Dawley rats.

    PubMed

    Inegbenebor, U; Ebomoyi, M I; Onyia, K A; Amadi, K; Aigbiremolen, A E

    2009-12-01

    Alligator pepper (Aframomum melegueta) is a spice that is widely used in many cultures for entertainment, religious rites, food flavor and as a part of many traditional doctors medications. Pregnant women are among those who ingest Alligator pepper in these activities. This experiment was carried out to determine the health risk or benefit of Alligator pepper to pregnant women if any. Fifteen male rats and fifteen female rats of proven fertility from a pilot study were randomly paired in fifteen cages in a well ventilated room. After three days of mating, the males were withdrawn from the females, which were allowed to stay in their separate maternity cages for 18-25 days. The females in the control group were fed with normal rat chow and clean drinking water ad libitum for the duration of the experiment. Each of the rats in the experimental group was served 20 g of rat chow mixed with 50mg of Alligator pepper for one day only and thereafter fed with normal rat chow and clean drinking water ad libitum for 18-25 days. The rats in the control group had a mean of 7 litters each, while the rats in the experimental group did not litter at all. It was concluded that ingestion of large quantities of Alligator pepper poses a health risk to women in their first trimester of pregnancy. PMID:20234758

  14. Body temperatures and behavior of American alligators during cold winter weather

    SciTech Connect

    Brisbin, I.L., Jr.; Standora, E.A.; Vargo, M.J.

    1982-04-01

    Data from two large (188 and 135 kg) male alligators (Alligator mississippiensis) indicated that 4-5 C seemed to be the lowest body temperatures that they could endure with subsequent recovery. Although one animal in shallow water managed to keep a breathing hole open for several days, in ice that was 1.5 cm thick, it later died following a decrease of its body temperature to 4.0 C. The second alligator which was located in a deeper portion of the reservoir used both terrestrial and aquatic basking behavior to raise its body temperature and level of activity. Except in the case of basking events, there was not clear evidence of significant evaluations of the body temperatures of either the live or dead alligators above those of their adjacent water. When located side-by-side, diurnal cycles of deep body temperatures exceeding adjacent water temperatures to a maximum extent near dawn and usually falling below water temperatures during the afternoon and early evening hours. The physical properties and thermal inertia of the bodies of such large alligators, when placed in appropriate microclimates, may be sufficient in themselves to explain the general patterns and levels of body temperature changes observed at these low temperatures.

  15. Molecular cloning, characterization, tissue distribution and mRNA expression changes during the hibernation and reproductive periods of estrogen receptor alpha (ESR1) in Chinese alligator, Alligator sinensis.

    PubMed

    Zhang, Ruidong; Hu, Yuehong; Wang, Huan; Yan, Peng; Zhou, Yongkang; Wu, Rong; Wu, Xiaobing

    2016-10-01

    Chinese alligator, Alligator sinensis, is a critically endangered reptile species unique to China. Little is known about the mechanism of growth- and reproduction-related hormones gene expression in Chinese alligator. Estrogens play important roles in regulating multiple reproduction- and non-reproduction-related functions by binding to their corresponding receptors. Here, the full-length cDNA of estrogen receptor alpha (ERα/ESR1) was cloned and sequenced from Chinese alligator for the first time, which comprises 1764bp nucleotides and encodes a predicted protein of 587 amino acids. Phylogenetic analysis of ESR1 showed that crocodilians and turtles were the sister-group of birds. The results of real-time quantitative PCR indicated that the ESR1 mRNA was widely expressed in the brain and peripheral tissues. In the brain and pituitary gland, ESR1 was most highly transcribed in the cerebellum. But in other peripheral tissues, ESR1 mRNA expression level was the highest in the ovary. Compared with hibernation period, ESR1 mRNA expression levels were increased significantly in the reproductive period (P<0.05) in cerebellum, pituitary gland, liver, spleen, lung, kidney and ovary, while no significant change in other examined tissues (P>0.05). The ESR1 mRNA expression levels changes during the two periods of different tissues suggested that ESR1 might play an important role in mediation of estrogenic multiple reproductive effects in Chinese alligator. Furthermore, it was the first time to quantify ESR1 mRNA level in the brain of crocodilians, and the distribution and expression of ESR1 mRNA in the midbrain, cerebellum and medulla oblongata was also reported for the first time in reptiles. PMID:27212643

  16. Animal-borne imaging reveals novel insights into the foraging behaviors and Diel activity of a large-bodied apex predator, the American alligator (Alligator mississippiensis).

    PubMed

    Nifong, James C; Nifong, Rachel L; Silliman, Brian R; Lowers, Russell H; Guillette, Louis J; Ferguson, Jake M; Welsh, Matthew; Abernathy, Kyler; Marshall, Greg

    2014-01-01

    Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here we use animal-borne imaging systems (Crittercam) to study the foraging behavior and activity patterns of a cryptic, large-bodied predator, the American alligator (Alligator mississippiensis) in two estuaries of coastal Florida, USA. Using retrieved video data we examine the variation in foraging behaviors and activity patterns due to abiotic factors. We found the frequency of prey-attacks (mean = 0.49 prey attacks/hour) as well as the probability of prey-capture success (mean = 0.52 per attack) were significantly affected by time of day. Alligators attempted to capture prey most frequently during the night. Probability of prey-capture success per attack was highest during morning hours and sequentially lower during day, night, and sunset, respectively. Position in the water column also significantly affected prey-capture success, as individuals' experienced two-fold greater success when attacking prey while submerged. These estimates are the first for wild adult American alligators and one of the few examples for any crocodilian species worldwide. More broadly, these results reveal that our understandings of crocodilian foraging behaviors are biased due to previous studies containing limited observations of cryptic and nocturnal foraging interactions. Our results can be used to inform greater understanding regarding the top-down effects of American alligators in estuarine food webs. Additionally, our results highlight the importance and power of using animal-borne imaging when

  17. Animal-Borne Imaging Reveals Novel Insights into the Foraging Behaviors and Diel Activity of a Large-Bodied Apex Predator, the American Alligator (Alligator mississippiensis)

    PubMed Central

    Nifong, James C.; Nifong, Rachel L.; Silliman, Brian R.; Lowers, Russell H.; Guillette, Louis J.; Ferguson, Jake M.; Welsh, Matthew; Abernathy, Kyler; Marshall, Greg

    2014-01-01

    Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here we use animal-borne imaging systems (Crittercam) to study the foraging behavior and activity patterns of a cryptic, large-bodied predator, the American alligator (Alligator mississippiensis) in two estuaries of coastal Florida, USA. Using retrieved video data we examine the variation in foraging behaviors and activity patterns due to abiotic factors. We found the frequency of prey-attacks (mean = 0.49 prey attacks/hour) as well as the probability of prey-capture success (mean = 0.52 per attack) were significantly affected by time of day. Alligators attempted to capture prey most frequently during the night. Probability of prey-capture success per attack was highest during morning hours and sequentially lower during day, night, and sunset, respectively. Position in the water column also significantly affected prey-capture success, as individuals’ experienced two-fold greater success when attacking prey while submerged. These estimates are the first for wild adult American alligators and one of the few examples for any crocodilian species worldwide. More broadly, these results reveal that our understandings of crocodilian foraging behaviors are biased due to previous studies containing limited observations of cryptic and nocturnal foraging interactions. Our results can be used to inform greater understanding regarding the top-down effects of American alligators in estuarine food webs. Additionally, our results highlight the importance and power of using animal

  18. POST weed control using halosulfuron in direct-seeded watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is needed in watermelon (Citrullus lanatus) production to avoid losses in crop yield and marketability that result from weed interference. Not only does weed control provide direct benefits to crop yields, but uncontrolled weeds hamper the management of insect and disease pests and redu...

  19. A survey of weeds and herbicides in Georgia Pecan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey was conducted in 2012 in Georgia to determine the most troublesome weeds in pecan orchards and document common weed control practices using herbicides. Weed control practices and infestations in pecan were divided between winter and summer seasons. The most troublesome pecan winter weed s...

  20. Weed species shifts in glyphosate-resistant crops.

    PubMed

    Owen, Micheal D K

    2008-04-01

    The adoption of glyphosate-based crop production systems has been one of the most important revolutions in the history of agriculture. Changes in weed communities owing to species that do not respond to current glyphosate-based management tactics are rapidly increasing. Clearly, glyphosate-resistant crops (GRCs) do not influence weeds any more than non-transgenic crops. For most crops, the trait itself is essentially benign in the environment. Rather, the weed control tactics imposed by growers create the ecological selection pressure that ultimately changes the weed communities. This is seen in the adoption of conservation tillage and weed management programs that focus on one herbicide mode of action and have hastened several important weed population shifts. Tillage (disturbance) is one of the primary factors that affect changes in weed communities. The intense selection pressure from herbicide use will result in the evolution of herbicide-resistant weed biotypes or shifts in the relative prominence of one weed species in the weed community. Changes in weed communities are inevitable and an intrinsic consequence of growing crops over time. The glyphosate-based weed management tactics used in GRCs impose the selection pressure that supports weed population shifts. Examples of weed population shifts in GRCs include common waterhemp [Amaranthus tuberculatus (Moq ex DC) JD Sauer], horseweed (Conyza canadensis L), giant ragweed (Ambrosia trifida L) and other relatively new weed problems. Growers have handled these weed population shifts with varying success depending on the crop. PMID:18232055

  1. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  2. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  3. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  4. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  5. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  6. Weed Garden: An Effective Tool for Extension Education

    ERIC Educational Resources Information Center

    Beck, Leslie; Patton, Aaron J.

    2015-01-01

    A weed garden was constructed to quantify and improve identification skills among clientele. The garden was planted with over 100 weed species based on surveys on problematic weeds. The weed garden proved useful for introducing additional hands-on learning activities into traditional lecture-based seminars. Through seminar and field day attendee…

  7. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  8. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Designation of noxious weeds. 360.200 Section 360.200... SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds. The Administrator has determined that it is necessary to designate the following plants 1 as noxious weeds...

  9. 7 CFR 201.16 - Noxious-weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Noxious-weed seeds. 201.16 Section 201.16 Agriculture... REGULATIONS Labeling Agricultural Seeds § 201.16 Noxious-weed seeds. (a) Except for those kinds of noxious-weed seeds shown in paragraph (b) of this section, the names of the kinds of noxious-weed seeds and...

  10. "Digital Sampling": Mapping Weed Presence in Fallow Fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growers need maps of the distribution of weeds in their fields to reduce herbicide use with site-specific weed management (SSWM). Remote sensing is key to successful weed mapping and sophisticated hyper- and multi-spectral image-based systems appear promising for detecting weed patches and identifyi...

  11. Antiglycation, antioxidant and toxicological potential of polyphenol extracts of alligator pepper, ginger and nutmeg from Nigeria

    PubMed Central

    Kazeem, MI; Akanji, MA; Hafizur, Rahman M; Choudhary, MI

    2012-01-01

    Objective To evaluate the antioxidant and antiglycation potential of polyphenols from three spices; alligator pepper, ginger and nutmeg. Methods Polyphenol extracts of these spices were subjected to brine-shrimp lethality assay, phytotoxicity test, DPPH and superoxide anion radical scavenging as well as BSA-glucose antiglycation assay. Results Results obtained showed that polyphenol extract of ginger has the highest antioxidant potential with IC50 0.075 and 0.070 mg/mL for DPPH and superoxide anion radical scavenging assay while alligator pepper displayed highest antiglycation activity with IC50 0.125 mg/mL. However, nutmeg extract exhibited weakest cytotoxic and phytotoxic potential with LD50 4359.70 and 1490 µg/mL respectively. Conclusions It can be concluded that the polyphenol extracts of alligator pepper, ginger and nutmeg displayed good antioxidant as well as antiglycation potential and are safe for consumption. PMID:23570003

  12. Coplanar PCB distribution between chorioallantoic membranes and eggs of alligators and Loggerhead sea turtles

    SciTech Connect

    Bargar, T.A.; Cobb, G.P.

    1995-12-31

    The relative distribution of coplanar polychlorinated biphenyls (PCBs) between chorioallantoic membranes (CAMS) and eggs was investigated in inviable American alligator (Alligator mississippiensis) and Loggerhead sea turtle (Caretta caretra) eggs. Cam and egg extracts were fractionated by HPLC using a porous graphitic column (PGC) and an in line switching valve to separate coplanar from non-coplanar PCBs. The fractions were collected, concentrated by nitrogen evaporation, and injected on GC-ECD (60M DB-5 capillary column) for quantification. Alligator and Loggerhead sea turtle eggs contain toxicologically significant coplanar PCBs. Mono-ortho substituted PCBs were present with greater frequency relative to non-ortho substituted PCBs in both eggs and CAMS. The presence of coplanar PCBs in eggs appears to be correlated to coplanar PCB presence in CAMS. The chorioallantoic membrane could serve as a biomarker of embryo exposure to coplanar PCBs.

  13. Subglottal pressure and fundamental frequency control in contact calls of juvenile Alligator mississippiensis

    PubMed Central

    Riede, Tobias; Tokuda, Isao T.; Farmer, C. G.

    2011-01-01

    SUMMARY Vocalization is rare among non-avian reptiles, with the exception of the crocodilians, the sister taxon of birds. Crocodilians have a complex vocal repertoire. Their vocal and respiratory system is not well understood but appears to consist of a combination of features that are also found in the extremely vocal avian and mammalian taxa. Anatomical studies suggest that the alligator larynx is able to abduct and adduct the vocal folds, but not to elongate or shorten them, and is therefore lacking a key regulator of frequency, yet alligators can modulate fundamental frequency remarkably well. We investigated the morphological and physiological features of sound production in alligators. Vocal fold length scales isometrically across a wide range of alligator body sizes. The relationship between fundamental frequency and subglottal pressure is significant in some individuals at some isolated points, such as call onset and position of maximum fundamental frequency. The relationship is not consistent over large segments of the call. Fundamental frequency can change faster than expected by pressure changes alone, suggesting an active motor pattern controls frequency and is intrinsic to the larynx. We utilized a two-mass vocal fold model to test whether abduction and adduction could generate this motor pattern. The fine-tuned interplay between subglottal pressure and glottal adduction can achieve frequency modulations much larger than those resulting from subglottal pressure variations alone and of similar magnitude, as observed in alligator calls. We conclude that the alligator larynx represents a sound source with only two control parameters (subglottal pressure and vocal fold adduction) in contrast to the mammalian larynx in which three parameters can be altered to modulate frequency (subglottal pressure, vocal fold adduction and length/tension). PMID:21865521

  14. Dujardinascaris gigantea sp. n. (Nematoda: Ascaridida) from the critically endangered crocodile Alligator sinensis Fauvel (Reptilia: Crocodylia).

    PubMed

    Zhao, Jin-Hong; Li, Liang; Guo, Yan-Ning; Zhang, Lu-Ping

    2015-03-01

    The Chinese alligator Alligator sinensis Fauvel (Reptilia: Crocodylia) is considered as one of the most critically endangered species of the 23 extant crocodiles. However, our knowledge of the helminth parasites of this rare animal is completely lacking. During a helminthological survey of reptiles in China, we found a new ascaridoid nematode, Dujardinascaris gigantea sp. n. from A. sinensis. The morphology of D. gigantea sp. n. was studied using light and scanning electron microscopy. The new species was also characterised using molecular methods by sequencing and analysing the small ribosomal DNA (18S) and the second internal transcribed spacer (ITS-2). PMID:24924435

  15. EBIPM 2013 planner for preventing weed invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a calendar format, this publication is designed for land managers to make management decisions for preventing weed invasions in a timely manner. For each month there are recommendations for wee prevention management actions....

  16. Using Weeds and Wildflowers to Study Plants.

    ERIC Educational Resources Information Center

    Nowak, Nancy

    1984-01-01

    Offers suggestions for activities in which local weeds and wildflowers are used to study a variety of topics. These topics include classification, ecological succession, and mapping. Also lists the types of experiments students can perform with these plants. (JN)

  17. Kyllinga, troublesome sedge weeds in turf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kyllinga sedges are troublesome weeds in turf, lawns, flowerbeds, seasonally wet right-of-ways, vegetable crops, nursery plantings, and container plants. Descriptions, illustrations, and biological information are presented for green kyllinga (Kyllinga brevifolia Rottb.), false green kyllinga (Kylli...

  18. Global perspective of herbicide-resistant weeds.

    PubMed

    Heap, Ian

    2014-09-01

    Two hundred and twenty weed species have evolved resistance to one or more herbicides, and there are now 404 unique cases (species × site of action) of herbicide-resistant weeds globally. ALS inhibitor-resistant weeds account for about a third of all cases (133/404) and are particularly troublesome in rice and cereals. Although 71 weed species have been identified with triazine resistance, their importance has dwindled with the shift towards Roundup Ready® crops in the USA and the reduction of triazine usage in Europe. Forty-three grasses have evolved resistance to ACCase inhibitors, with the most serious cases being Avena spp., Lolium spp., Phalaris spp., Setaria spp. and Alopecurus myosuroides, infesting more than 25 million hectares of cereal production globally. Of the 24 weed species with glyphosate resistance, 16 have been found in Roundup Ready® cropping systems. Although Conyza canadensis is the most widespread glyphosate-resistant weed, Amaranthus palmeri and Amaranthus tuberculartus are the two most economically important glyphosate-resistant weeds because of the area they infest and the fact that these species have evolved resistance to numerous other herbicide sites of action, leaving growers with few herbicidal options for their control. The agricultural chemical industry has not brought any new herbicides with novel sites of action to market in over 30 years, making growers reliant on using existing herbicides in new ways. In addition, tougher registration and environmental regulations on herbicides have resulted in a loss of some herbicides, particularly in Europe. The lack of novel herbicide chemistries being brought to market combined with the rapid increase in multiple resistance in weeds threatens crop production worldwide. PMID:24302673

  19. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    SciTech Connect

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; Tuberville, Tracey D.

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3₋), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. In conclusion, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood.

  20. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    DOE PAGESBeta

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; Tuberville, Tracey D.

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressuremore » of carbon dioxide (PCO2), bicarbonate (HCO3₋), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. In conclusion, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood.« less

  1. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser.

    PubMed

    Hamilton, Matthew T; Finger, John W; Winzeler, Megan E; Tuberville, Tracey D

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3 (-)), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F 2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. Lastly, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood. PMID:27382469

  2. Evaluating the effect of sample type on American alligator (Alligator mississippiensis) analyte values in a point-of-care blood analyser

    PubMed Central

    Hamilton, Matthew T.; Finger, John W.; Winzeler, Megan E.; Tuberville, Tracey D.

    2016-01-01

    The assessment of wildlife health has been enhanced by the ability of point-of-care (POC) blood analysers to provide biochemical analyses of non-domesticated animals in the field. However, environmental limitations (e.g. temperature, atmospheric humidity and rain) and lack of reference values may inhibit researchers from using such a device with certain wildlife species. Evaluating the use of alternative sample types, such as plasma, in a POC device may afford researchers the opportunity to delay sample analysis and the ability to use banked samples. In this study, we examined fresh whole blood, fresh plasma and frozen plasma (sample type) pH, partial pressure of carbon dioxide (PCO2), bicarbonate (HCO3−), total carbon dioxide (TCO2), base excess (BE), partial pressure of oxygen (PO2), oxygen saturation (sO2) and lactate concentrations in 23 juvenile American alligators (Alligator mississippiensis) using an i-STAT CG4+ cartridge. Our results indicate that sample type had no effect on lactate concentration values (F2,65 = 0.37, P = 0.963), suggesting that the i-STAT analyser can be used reliably to quantify lactate concentrations in fresh and frozen plasma samples. In contrast, the other seven blood parameters measured by the CG4+ cartridge were significantly affected by sample type. Lastly, we were able to collect blood samples from all alligators within 2 min of capture to establish preliminary reference ranges for juvenile alligators based on values obtained using fresh whole blood. PMID:27382469

  3. Follicle-stimulating hormone receptor (FSHR) in Chinese alligator, Alligator sinensis: molecular characterization, tissue distribution and mRNA expression changes during the female reproductive cycle.

    PubMed

    Zhang, Rui; Zhang, Shengzhou; Zhu, Xue; Zhou, Yongkang; Wu, Xiaobing

    2015-05-01

    The follicle-stimulating hormone (FSH) plays a central role in vertebrate reproduction, with the actions of FSH mediated by FSH receptors (FSHRs) on the granulosa cells of the ovary. The present study reports the cloning and characterization of FSHR in Chinese alligator, Alligator sinensis (caFSHR), and its tissue distribution and mRNA expression changes during the reproductive cycle. The mature protein of caFSHR displays typical features of the glycoprotein hormone receptor family, but also contains some remarkable differences when compared with other vertebrate FSHRs. The deduced amino acid sequence of the caFSHR shares identity of 85% with Chinese softshell turtle, 84-87% with birds, 77-78% with mammals, 67-73% with amphibians and 51-58% with fishes. Phylogenetic tree analysis of the FSHR amino acid sequence indicated that alligators cluster into the bird branch. Tissue expression analysis showed that caFSHR was not only expressed in the ovary, but also in the stomach, intestine, pancreas liver and oviduct at similar levels, while it was not detectable in heart, thymus or thyroid. Expression of caFSHR in the ovary is high in May (breeding prophase) and peaks in July during the breeding period, where it is maintained at high levels through September (breeding anaphase). Expression decreases significantly in November (hibernating period) and then remains relatively low from January to March (hibernating period). These temporal changes in FSHR expression suggest that it plays an important role in promoting ovarian development during the female reproductive cycle of Chinese alligator. PMID:25765682

  4. The Invasive Plant Alternanthera philoxeroides Was Suppressed More Intensively than Its Native Congener by a Native Generalist: Implications for the Biotic Resistance Hypothesis

    PubMed Central

    Fan, Shufeng; Yu, Dan; Liu, Chunhua

    2013-01-01

    Prior studies on preferences of native herbivores for native or exotic plants have tested both the enemy release hypothesis and the biotic resistance hypothesis and have reported inconsistent results. The different levels of resistance of native and exotic plants to native herbivores could resolve this controversy, but little attention has been paid to this issue. In this study, we investigated population performance, photosynthesis, leaf nitrogen concentration, and the constitutive and induced resistances of the successful invasive plant, Alternanthera philoxeroides, and its native congener, Alternanthera sessilis, in the presence of three population densities of the grasshopper, Atractomorpha sinensis. When the grasshopper was absent, leaf biomass, total biomass, photosynthesis, and leaf nitrogen concentration of A. philoxeroides were higher than those of A. sessilis. However, the morphological and physiological performances of A. philoxeroides were all decreased more intensively than A. sessilis after herbivory by grasshoppers. Especially as the concentrations of constitutive lignin and cellulose in leaf of A. philoxeroides were higher than A. sessilis, A. philoxeroides exhibited increased leaf lignin concentration to reduce its palatability only at severe herbivore load, whereas, leaf lignin, cellulose, and polyphenolic concentrations of A. sessilis all increased with increasing herbivory pressure, and cellulose and polyphenolic concentrations were higher in A. sessilis than in A. philoxeroides after herbivory. Our study indicated that the capability of the invasive plant to respond to native insect damage was lower than the native plant, and the invasive plant was suppressed more intensively than its native congener by the native insect. Our results support the biotic resistance hypothesis and suggest that native herbivores can constrain the abundance and reduce the adverse effects of invasive species. PMID:24386236

  5. Simple solar technology saves money for alligator farms

    SciTech Connect

    Goldman, A.

    1993-01-01

    In 1990, a high-volume solar thermal water-heating system in Florida was installed in Okeechobee County by Solar Development, Inc. (SDI). The system is designed to provide large quantities of hot water for commercial use and heat water to as high as 140[degrees]F. The design in Florida is known as a Shallow Solar Pond (SSP). It was completed with the help of the Florida Alligator Farmers Association, the Florida Energy Office, Foster Farms, and SDI. The SSP is a modular system built on site and modified to meet the specific needs of each application. The tank and the collector are the same unit, which keeps the system cost very low. The typical SSP module is 16 feet wide and up to 200 feet long. The module contains one or two reinforced-rubber flat water bags similar to a water bed. The bags rest on a layer of insulation or sand inside concrete or fiberglass curbs. In the Foster Farms SSP, the insulation was omitted and the water bags are placed on sand. The bag is protected against damage and heat loss by greenhouse-type glazing. At Foster Farms there are 3 SSPs, set in approximately 8,000 square feet, with two 5,000-gallon bags per unit. In addition, there is a pressurizing pump/tank system. Every morning, the heated water from the bags drains into a sump tank. While the bags are emptied into the backup system, well water is pumped in and the solar heating process starts all over again.

  6. TRPV4 associates environmental temperature and sex determination in the American alligator

    PubMed Central

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Saito, Shigeru; Lowers, Russell H.; Ogino, Yukiko; Fukuta, Naomi; Katsu, Yoshinao; Ohta, Yasuhiko; Tominaga, Makoto; Guillette Jr, Louis J.; Iguchi, Taisen

    2015-01-01

    Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual’s genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism. PMID:26677944

  7. Effects of salinity on growth and ion regulation of juvenile alligator gar Atractosteus spatula.

    PubMed

    Schwarz, Daniel E; Allen, Peter J

    2014-03-01

    The alligator gar (Atractosteus spatula) is a primitive euryhaline fish, found primarily in estuaries and freshwater drainages associated with the northern Gulf of Mexico. The extent of its hypo-osmotic regulatory abilities is not well understood. In order to determine how salinity affects growth rates and ionic and osmoregulation, juvenile alligator gar (330 days after hatch; 185 g) were exposed to 4 different salinities (0, 8, 16, and 24 ppt) for a 30-day period. Specific growth rate, plasma osmolality and ion concentrations, gill and gastrointestinal tract Na(+), K(+)-ATPase activities, and drinking rate were compared. Juvenile alligator gar were able to tolerate hyperosmotic salinities up to 24 ppt for a 30 day period, albeit with decreased growth resulting largely from decreased food consumption. Plasma osmolality and ionic concentrations were elevated in hyperosmotic salinities, and drinking rates and gastrointestinal tract Na(+), K(+)-ATPase activities increased, particularly in the pyloric caeca, presumably the primary location of water absorption. Therefore, juvenile alligator gar<1 year of age are capable of prolonged exposure to hyperosmotic salinities, but, based on the inference of these data, require access to lower salinities for long-term survival. PMID:24368134

  8. TRPV4 associates environmental temperature and sex determination in the American alligator.

    PubMed

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Saito, Shigeru; Lowers, Russell H; Ogino, Yukiko; Fukuta, Naomi; Katsu, Yoshinao; Ohta, Yasuhiko; Tominaga, Makoto; Guillette, Louis J; Iguchi, Taisen

    2015-01-01

    Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual's genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism. PMID:26677944

  9. A group of alligators basks in the sun and rest in the water at KSC.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This pond near Schwartz Rd. at Kennedy Space Center is host to a least the nine alligators shown on the banks and in the water. Nearly 5,000 alligators can be found in canals, ponds, and waterways throughout the Center and the Merritt Island National Wildlife Refuge, which shares a boundary with the Center. American alligators feed and rest in the water, and lay their eggs in dens they dig into the banks. The young alligators spend their first several weeks in these dens. The Wildlife Refuge encompasses 92,000 acres that are a habitat for more than 331 species of birds, 31 mammals, 117 fishes, and 65 amphibians and reptiles. The marshes and open water of the refuge provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds, as well as a variety of insects.

  10. Effects of salinity on growth and ion regulation of juvenile alligator gar Atractosteus spatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The alligator gar (Atractosteus spatula) is a primitive euryhaline fish, found primarily in estuaries and freshwater drainages associated with the northern Gulf of Mexico. The extent of its hypo-osmotic regulatory abilities is not well understood. In order to determine how salinity affects growth ra...

  11. Achieving environmentally relevant organochlorine pesticide concentrations in eggs through maternal exposure in Alligator mississippiensis

    USGS Publications Warehouse

    Rauschenberger, R.H.; Wiebe, J.J.; Buckland, J.E.; Smith, Joe T.; Sepulveda, M.S.; Gross, T.S.

    2004-01-01

    Alligator mississippiensis eggs from organochlorine pesticide (OCP) contaminated sites in Florida exhibit high rates of embryonic mortality compared to reference sites (p<0.05). The objective of the present study was to use captive adult alligators to test the hypotheses that maternal exposure to OCPs results in increased OCP concentrations in eggs, and that increased exposure is associated with increased embryonic mortality. A total of 24 adult alligators (8 males and 16 females) were housed in eight pens. Eight females in four pens were dosed with a mixture of p,p'-DDE, toxaphene, dieldrin, and chlordane at a rate of 0.2 ? 0.01 mg/kg/day for 274 ? 8 days. Treated females produced eggs containing higher OCP concentrations (12,814 ? 813 ng/g yolk) than controls (38 ? 4 ng/g yolk). Eggs of treated females exhibited decreased viability (13 ? 22%) as compared to controls (45 ? 20%). Results indicated that 0.6% of administered OCPs were maternally transferred to the eggs of American alligators, and that maternal exposure is associated with decreased egg/embryo viability in this species.

  12. Evaluating recent taxonomic changes for alligator snapping turtles (Testudines: Chelydridae).

    PubMed

    Folt, Brian; Guyer, Craig

    2015-01-01

    The Alligator Snapping Turtle (Macrochelys temminckii Troost in Harlan 1835, sensu lato) has been historically treated as a single, wide-ranging species, until a recently published paper by Thomas et al. (2014; hereafter Thomas et al.) analyzed variation in morphology and mitochondrial DNA sequence data to describe two new species of Macrochelys: the Apalachicola Alligator Snapping Turtle (Macrochelys apalachicolae Thomas, Granatosky, Bourque, Krysko, Moler, Gamble, Suarez, Leone & Roman 2014) and the Suwannee Alligator Snapping Turtle (Macrochelys suwanniensis Thomas, Granatosky, Bourque, Krysko, Moler, Gamble, Suarez, Leone & Roman 2014). The specific epithet temminckii was retained for populations in drainages from the Yellow River in Alabama and Florida west to the San Antonio River, Texas. Because populations of Macrochelys have been historically exploited by humans (Pritchard 1989) and the life-history strategies of large, long-lived turtles make them susceptible to declines from harvest (Congdon et al. 1994), a sound understanding of species delimitation and richness is critical for the conservation of alligator snapping turtles, especially if the acceptance of a widely distributed species disguises the presence of multiple, smaller-ranged species. PMID:25947748

  13. Combining a weed traits database with a population dynamics model predicts shifts in weed communities

    PubMed Central

    Storkey, J; Holst, N; Bøjer, O Q; Bigongiali, F; Bocci, G; Colbach, N; Dorner, Z; Riemens, M M; Sartorato, I; Sønderskov, M; Verschwele, A

    2015-01-01

    A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, populated and analysed, initially using data for 19 common European weeds, to begin to consolidate trait data in a single repository. The initial choice of traits was driven by the requirements of empirical models of weed population dynamics to identify correlations between traits and model parameters. These relationships were used to build a generic model, operating at the level of functional traits, to simulate the impact of increasing herbicide and fertiliser use on virtual weeds along gradients of seed weight and maximum height. The model generated ‘fitness contours’ (defined as population growth rates) within this trait space in different scenarios, onto which two sets of weed species, defined as common or declining in the UK, were mapped. The effect of increasing inputs on the weed flora was successfully simulated; 77% of common species were predicted to have stable or increasing populations under high fertiliser and herbicide use, in contrast with only 29% of the species that have declined. Future development of the WTDB will aim to increase the number of species covered, incorporate a wider range of traits and analyse intraspecific variability under contrasting management and environments. PMID:26190870

  14. Weed escapes and delayed weed emergence in glyphosate-resistant soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During 2001 and 2002, field experiments were conducted in soybean crops at four Minnesota locations with the aim of studying the effects of different glyphosate treatments (one-pass glyphosate, two-pass glyphosate) on weed control and weed community composition by focusing on the identity and abunda...

  15. SHIFTS IN VINEYARD WEED SEED BANK COMPOSITION IN REPONSE TO ORGANIC AND CONVENTIONAL WEED CONTROL PRACTICES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this research was to compare the organic weed control practice, soil cultivation, to the conventional practice, applications of the herbicide, glyphosate, in terms of their effects on weed seed bank in a vineyard system. The experiment was conducted in a commercial winegrape vineyard in t...

  16. Plant Pathogens at Work: Progress and Possibilities for Weed Biocontrol Part 2. Improving Weed Control Efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of plant pathogenic weed biological control agents can be approached using two strategies, termed the classical and biological approaches. The classical involves the search for pathogens in the native range of an invasive weed and its importation and release into the area of introdu...

  17. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China

    PubMed Central

    Geng, Yupeng; van Klinken, Rieks D.; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas. PMID:26941769

  18. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China.

    PubMed

    Geng, Yupeng; van Klinken, Rieks D; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas. PMID:26941769

  19. The Good, the Bad, and the Unknown: Microbial Symbioses of the American Alligator.

    PubMed

    Keenan, Sarah W; Elsey, Ruth M

    2015-12-01

    Vertebrates coexist with microorganisms in diverse symbiotic associations that range from beneficial to detrimental to the host. Most research has aimed at deciphering the nature of the composite microbial assemblage's genome, or microbiome, from the gastrointestinal (GI) tract and skin of mammals (i.e., humans). In mammals, the GI tract's microbiome aids digestion, enhances uptake of nutrients, and prevents the establishment of pathogenic microorganisms. However, because the GI tract microbiome of the American alligator (Alligator mississippiensis) is distinct from that of all other vertebrates studied to date, being comprised of Fusobacteria in the lower GI tract with lesser abundances of Firmicutes, Proteobacteria, and Bacteroidetes, the function of these assemblages is largely unknown. This review provides a synthesis of our current understanding of the composition of alligators' microbiomes, highlights the potential role of microbiome members in alligators' health (the good), and presents a brief summary of microorganisms detrimental to alligators' health (the bad) including Salmonella spp. and others. Microbial assemblages of the GI tract have co-evolved with their vertebrate host over geologic time, which means that evolutionary hypotheses can be tested using information about the microbiome. For reptiles and amphibians, the number of taxa studied at present is limited, thereby restricting evolutionary insights. Nevertheless, we present a compilation of our current understanding of reptiles' and amphibians' microbiomes, and highlight future avenues of research (the unknown). As in humans, composition of microbiome assemblages provides a promising tool for assessing hosts' health or disease. By further exploring present-day associations between symbiotic microorganisms in the microbiomes of reptiles and amphibians, we can better identify good (beneficial) and bad (detrimental) microorganisms, and unravel the evolutionary history of the acquisition of

  20. Isolation and expression of a novel alligator gene belonging to the Sox gene family.

    PubMed

    Zheng, Jifang; Hu, Nan; Zhu, Muyuan; Nu, Yaqing; Liu, Zhen

    2009-02-01

    Sox genes share a highly conserved DNA-binding motif, the HMG (high mobility group)-box domain, and have diverse roles in vertebrate embryonic development. A novel SRY-related cDNA (temporarily called Sox33) isolated from the Chinese alligator (Alligator sinensis) is 1,819 bp in length, with an open reading frame from 220 to 1113 bp, encoding a protein of 298 amino acids. Two putative polyadenylation signal sequences (AATAAA) are present upstream of the poly(A) tail in the 3' UTR (at 1255-1260 and 1774-1779). The putative protein contains an HMG-box domain most closely related to hSox12, mSox4, rtSox11, and mSox11 homologs, indicating that alligator Sox33 belongs to group C in the Sox gene family. Alligator adult and developing tissues were tested for Sox33 mRNA by independent Northern blots using a 336-bp probe (at 907-1243) between the HMG-box and the poly(A) site I and a 277-bp probe (at 1477-1754) between the two polyadenylation sites. Two transcripts (1.3 kb and 1.8 kb) in developing brain and one (1.8 kb) in adult brain were identified by the 336-bp probe; only one transcript (1.8 kb) in developing and adult brains was detected by the 277-bp probe. The results suggest that alligator Sox33 may use a different polyadenylation mechanism in the developing brain and play a role in the development and maintenance of the nervous system. PMID:19169861

  1. Genome analysis and signature discovery for diving and sensory properties of the endangered Chinese alligator

    PubMed Central

    Wan, Qiu-Hong; Pan, Sheng-Kai; Hu, Li; Zhu, Ying; Xu, Peng-Wei; Xia, Jin-Quan; Chen, Hui; He, Gen-Yun; He, Jing; Ni, Xiao-Wei; Hou, Hao-Long; Liao, Sheng-Guang; Yang, Hai-Qiong; Chen, Ying; Gao, Shu-Kun; Ge, Yun-Fa; Cao, Chang-Chang; Li, Peng-Fei; Fang, Li-Ming; Liao, Li; Zhang, Shu; Wang, Meng-Zhen; Dong, Wei; Fang, Sheng-Guo

    2013-01-01

    Crocodilians are diving reptiles that can hold their breath under water for long periods of time and are crepuscular animals with excellent sensory abilities. They comprise a sister lineage of birds and have no sex chromosome. Here we report the genome sequence of the endangered Chinese alligator (Alligator sinensis) and describe its unique features. The next-generation sequencing generated 314 Gb of raw sequence, yielding a genome size of 2.3 Gb. A total of 22 200 genes were predicted in Alligator sinensis using a de novo, homology- and RNA-based combined model. The genetic basis of long-diving behavior includes duplication of the bicarbonate-binding hemoglobin gene, co-functioning of routine phosphate-binding and special bicarbonate-binding oxygen transport, and positively selected energy metabolism, ammonium bicarbonate excretion and cardiac muscle contraction. Further, we elucidated the robust Alligator sinensis sensory system, including a significantly expanded olfactory receptor repertoire, rapidly evolving nerve-related cellular components and visual perception, and positive selection of the night vision-related opsin and sound detection-associated otopetrin. We also discovered a well-developed immune system with a considerable number of lineage-specific antigen-presentation genes for adaptive immunity as well as expansion of the tripartite motif-containing C-type lectin and butyrophilin genes for innate immunity and expression of antibacterial peptides. Multifluorescence in situ hybridization showed that alligator chromosome 3, which encodes DMRT1, exhibits significant synteny with chicken chromosome Z. Finally, population history analysis indicated population admixture 0.60-1.05 million years ago, when the Qinghai-Tibetan Plateau was uplifted. PMID:23917531

  2. Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming

    NASA Astrophysics Data System (ADS)

    Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

    2015-11-01

    Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction.

  3. Ecological Intensification Through Pesticide Reduction: Weed Control, Weed Biodiversity and Sustainability in Arable Farming.

    PubMed

    Petit, Sandrine; Munier-Jolain, Nicolas; Bretagnolle, Vincent; Bockstaller, Christian; Gaba, Sabrina; Cordeau, Stéphane; Lechenet, Martin; Mézière, Delphine; Colbach, Nathalie

    2015-11-01

    Amongst the biodiversity components of agriculture, weeds are an interesting model for exploring management options relying on the principle of ecological intensification in arable farming. Weeds can cause severe crop yield losses, contribute to farmland functional biodiversity and are strongly associated with the generic issue of pesticide use. In this paper, we address the impacts of herbicide reduction following a causal framework starting with herbicide reduction and triggering changes in (i) the management options required to control weeds, (ii) the weed communities and functions they provide and (iii) the overall performance and sustainability of the implemented land management options. The three components of this framework were analysed in a multidisciplinary project that was conducted on 55 experimental and farmer's fields that included conventional, integrated and organic cropping systems. Our results indicate that the reduction of herbicide use is not antagonistic with crop production, provided that alternative practices are put into place. Herbicide reduction and associated land management modified the composition of in-field weed communities and thus the functions of weeds related to biodiversity and production. Through a long-term simulation of weed communities based on alternative (?) cropping systems, some specific management pathways were identified that delivered high biodiversity gains and limited the negative impacts of weeds on crop production. Finally, the multi-criteria assessment of the environmental, economic and societal sustainability of the 55 systems suggests that integrated weed management systems fared better than their conventional and organic counterparts. These outcomes suggest that sustainable management could possibly be achieved through changes in weed management, along a pathway starting with herbicide reduction. PMID:26071767

  4. The oldest record of Alligator sinensis from the Late Pliocene of Western Japan, and its biogeographic implication

    NASA Astrophysics Data System (ADS)

    Iijima, Masaya; Takahashi, Keiichi; Kobayashi, Yoshitsugu

    2016-07-01

    The late Cenozoic fossil record of alligators in East Asia is crucial in understanding the origin and past distribution of Asian alligators that are now represented by a single species, Alligator sinensis. This study reports a partial skeleton of A. sinensis from the Late Pliocene (approximately 3.0 Ma) of western Japan. This Japanese A. sinensis is large in size (>200 cm total length), comparable to the maximum size of extant individuals. It demonstrates the oldest record of A. sinensis and wider distribution of this species in the past. Tectonic and geographic history of East Asia suggests that alligators presumably dispersed into Japan before 25 Ma or after 10 Ma, yet finally were wiped out from Japan due to the semi-isolated condition of the Japanese island arc and the deteriorated climate during the Plio-Pleistocene.

  5. Weed control in rose-scented geranium (Pelargonium spp).

    PubMed

    Kothari, Sushil K; Singh, Chandra P; Singh, Kamla

    2002-12-01

    Abstract: Field investigations were carried out during 1999 and 2000 to identify effective chemical/ cultural methods of weed control in rose-scented geranium (Pelargonium spp). The treatments comprised pre-emergence applications of oxyfluorfen (0.15, 0.20 and 0.25 kg AI ha(-1)) and pendimethalin (0.50, 0.75 and 1.00kg AI ha(-1)), successive hand weeding, hoeing and mulching using spent of lemon grass (at 5 tonnes ha(-1)) 45 days after planting (DAP), three hand-weedings 30, 60 and 90 DAP, weed-free (frequent manual weeding) and weedy control. Broad-leaf weeds were more predominant than grass and sedge weeds, accounting for 85.8% weed density and 93.0% weed dry weight in 1999 and 77.2% weed density and 93.9% weed dry weight in 2000. Unrestricted weed growth significantly reduced geranium oil yield, by 61.6% and 70.6% in 1999 and 2000, respectively. Pre-emergence application of pendimethalin (0.75-1.00 kgAI ha(-1)) or oxyfluorfen (0.25 kg AI ha(-1)), successive hand-weeding, hoeing and mulching and three hand-weedings were highly effective in reducing weed density and dry weight and gave oil yield comparable to the weed-free check. Application of oxyfluorfen (0.15 or 0.20 kg AI ha(-1)) and pendimethalin (0.50 kg AI ha(-1)) were less effective in controlling the weed species in geranium. None of the herbicides impaired the quality of rose-scented geranium oil measured in terms of citronellol and geraniol content. PMID:12477000

  6. STRATEGIES FOR DEVELOPING BIOHERBICIDES FOR SUSTAINABLE WEED MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological weed control is an important component in sustainable crop production systems. Environmental and social pressures that shift the dependency on chemical herbicides towards integrated weed management strategies have provided opportunities for use of bioherbicides. A pragmatic approach in ...

  7. Sequential applications of pelargonic acid for weed control in squash

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control can be a constant challenge, especially when dealing with the limited herbicide options available to organic vegetable producers. Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide weed control throughout the production season. Although...

  8. Weed control options for organically grown vine crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic melon production requires effective weed management practices for achieving acceptable crop yield and quality. Research conducted in 2010 in southeastern Oklahoma (Lane, OK) compared several possible weed management strategies for cantaloupe. Treatments included black plastic mulch, black wo...

  9. EAARL coastal topography--Alligator Point, Louisiana, 2010

    USGS Publications Warehouse

    Nayegandhi, Amar; Bonisteel-Cormier, J.M.; Wright, C.W.; Brock, J.C.; Nagle, D.B.; Vivekanandan, Saisudha; Fredericks, Xan; Barras, J.A.

    2012-01-01

    This project provides highly detailed and accurate datasets of a portion of Alligator Point, Louisiana, acquired on March 5 and 6, 2010. The datasets are made available for use as a management tool to research scientists and natural-resource managers. An innovative airborne lidar instrument originally developed at the National Aeronautics and Space Administration (NASA) Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multispectral color-infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for sub-meter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine aircraft, but the instrument was deployed on a Pilatus PC-6. A single pilot, a lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built processing system developed in a NASA-USGS collaboration. ALPS supports the exploration and processing of lidar data in an interactive or batch mode. Modules for presurvey flight-line definition, flight-path plotting, lidar raster and waveform investigation, and digital camera image playback have been developed. Processing algorithms have

  10. Herpetofaunal diversity of Alligator River National Wildlife Refuge, North Carolina

    USGS Publications Warehouse

    Meyers, J.M.; Pike, D.A.

    2006-01-01

    In the past century, habitat alteration and fragmentation have increased dramatically, which increases the need for improving our understanding of how species and biological communities react to these modifications. A national strategy on biological diversity has focused attention on how these habitat modifications affect species, especially herpetofauna (i.e., changes in species richness, community evenness and similarity, and dominant/rare species). As part of this strategy, we surveyed Alligator River National Wildlife Refuge, a coastal, mixed second-growth forested swamp (MFS) and pocosin wetland (PW), in North Carolina for amphibians and reptiles from September 2000 to August 2001. We randomly selected three sites (3 x 3 km) in two major habitat types (MFS, PW) and completed random surveys and trapping using transects, quadrats, nighttime aural road surveys, drift fences, canal transects, coverboards, incidental captures, and evening road surveys. We also collected herpetofauna opportunistically throughout the refuge to establish an updated species list. For analysis, we used Shannon-Weiner species diversity (H'), evenness (1'), species richness and species detectability (COMDYN4), and community percent similarity index to determine herpetofaunal community differences. We estimated 39 species in MFS and 32 species in PW (P < 0.10). Species detectability was similar between habitats (0.84 to 0.86). More reptilian species (+ 31 %) inhabited MFS than PW, but estimated amphibian species richness was identical (17 spp.). H' was higher (P < 0.000 I) for PW (2.6680) than for MFS (2.1535) because of lower J' in the latter (0.6214 vs. 0.8010). Dominance of three Rana species caused lower J' and H' in MFS. Similarity between the communities was 56.6%; we estimated 22-24 species in common for each habitat (95% CI = 18 to 31 spp.). We verified 49 of the 52 herpetofaunal species on the refuge that were known to exist in the area. Restoration of natural water flows may

  11. An Ultrasonic System for Weed Detection in Cereal Crops

    PubMed Central

    Andújar, Dionisio; Weis, Martin; Gerhards, Roland

    2012-01-01

    Site-specific weed management requires sensing of the actual weed infestation levels in agricultural fields to adapt the management accordingly. However, sophisticated sensor systems are not yet in wider practical use, since they are not easily available for the farmers and their handling as well as the management practice requires additional efforts. A new sensor-based weed detection method is presented in this paper and its applicability to cereal crops is evaluated. An ultrasonic distance sensor for the determination of plant heights was used for weed detection. It was hypothesised that the weed infested zones have a higher amount of biomass than non-infested areas and that this can be determined by plant height measurements. Ultrasonic distance measurements were taken in a winter wheat field infested by grass weeds and broad-leaved weeds. A total of 80 and 40 circular-shaped samples of different weed densities and compositions were assessed at two different dates. The sensor was pointed directly to the ground for height determination. In the following, weeds were counted and then removed from the sample locations. Grass weeds and broad-leaved weeds were separately removed. Differences between weed infested and weed-free measurements were determined. Dry-matter of weeds and crop was assessed and evaluated together with the sensor measurements. RGB images were taken prior and after weed removal to determine the coverage percentages of weeds and crop per sampling point. Image processing steps included EGI (excess green index) computation and thresholding to separate plants and background. The relationship between ultrasonic readings and the corresponding coverage of the crop and weeds were assessed using multiple regression analysis. Results revealed a height difference between infested and non-infested sample locations. Density and biomass of weeds present in the sample influenced the ultrasonic readings. The possibilities of weed group discrimination were

  12. Guidelines for management of noxious weeds at Hanford

    SciTech Connect

    Roos, R.C.; Malady, M.B.

    1995-10-27

    Integrated Pest Management Services is responsible for management and control of noxious weeds on the Hanford Site. Weed species and populations are prioritized and objective defined, according to potential site and regional impact. Population controls are implemented according to priority. An integrated approach is planned for noxious weed control in which several management options are considered and implemented separately or in coordination to best meet management objectives. Noxious weeds are inventories and monitored to provide information for planning and program review.

  13. Weed Community Response to No-Till in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scientists and producers in Ukraine are interested in no-till crop production, but are concerned about weed management. In North America, producers have used no-till systems for several decades without increasing weed community density in croplands. Initially, weed density escalated with no-till, ...

  14. Weed control through seedling abrasion with an organic fertilizer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many tools exist to control weeds in organic crops, and each has utility in specific situations. Nevertheless, surveys of organic farmers indicate that weed management often is second only to labor supply as their main bottleneck for success. Consequently, new tactics for managing weeds are desirabl...

  15. Weed management research in alfalfa seed production in Washington state

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is an important component of producing high quality and high yielding alfalfa seed. Alfalfa seed is produced with wider row and lower plant populations than alfalfa forage requiring greater weed management inputs. Flumioxazin was evaluated for weed control in alfalfa seed and forage pro...

  16. Allelopathic weed suppression through the use of cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ensuring sufficient food and fiber production for future generations can be hampered by limited options for weed control, particularly in developing countries where yields are reduced by up to 25% by weed species. Identifying and detailing sustainable weed control measures that can be implemented t...

  17. WEEDS AS HOSTS FOR THE SOUTHERN ROOT-KNOT NEMATODE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The southern root-knot nematode, Meloidogyne incognita, can reproduce on many different plants, including many weeds, but the amount of reproduction that occurs on weeds is not well documented. This study was conducted to document the relative host status of weeds common in Georgia. Seeds of cotton,...

  18. Agricultural weed research: a critique and two proposals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two broad aims drive weed science research: improved management and improved understanding of weed biology and ecology. In recent years, agricultural weed research addressing these two aims has effectively split into separate sub-disciplines despite repeated calls for greater integration. While some...

  19. Onion and weed response to mustard (Sinapis alba) seed meal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in organic onion production is often difficult and expensive, requiring numerous cultivations and extensive hand-weeding. Onion safety and weed control with mustard seed meal (MSM) derived from Sinapis alba was evaluated in greenhouse and field trials. MSM applied at 110, 220, and 440 g...

  20. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  1. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Aeginetia...

  2. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  3. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  4. 7 CFR 361.6 - Noxious weed seeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Noxious weed seeds. 361.6 Section 361.6 Agriculture..., DEPARTMENT OF AGRICULTURE IMPORTATION OF SEED AND SCREENINGS UNDER THE FEDERAL SEED ACT § 361.6 Noxious weed... considered noxious weed seeds. (1) Seeds with no tolerances applicable to their introduction: Acacia...

  5. PROGRESS REPORT: WEED MANAGEMENT IN ORGANIC PEANUT PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies have been conducted in Tifton, GA since 2003 to develop weed management systems for organic peanut production. Trials in conventional tillage production systems evaluated row patterns, cultivation, and remedial weed management using propane flaming, clove oil, and citric acid. Weed control...

  6. Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

    ERIC Educational Resources Information Center

    Doersch, R. E.; And Others

    This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

  7. Linking theory and practice in ecological weed management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulation models of management effects on weed demography and the experience of successful organic and low-external-input farmers point in the same direction: long-term weed management success depends on diversified strategies that attack multiple weed life stages. In an era of declining research b...

  8. Weighing Abiotic and Biotic Influences on Weed Seed Predation Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. Current knowledge of weed seed predation focuses on biotic mechanisms, with less understood about the relative impact of abiotic variables. In order to quantify relative contributio...

  9. Weighing Abiotic and Biotic Influences on Weed Seed Predation Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed seed predation is an important ecosystem service supporting weed management in low-external-input agroecosystems. Current knowledge of weed seed predation in arable systems focuses on biotic mechanisms, with less understood about the relative impact of abiotic variables on this process. In orde...

  10. New approaches to understanding weed seed predation in agroecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postdispersal predation of weed seeds in arable systems can be a valuable ecosystem service, with the potential to support ecological approaches to weed management by reducing inputs to the soil seed bank. Scientific understanding of factors regulating weed seed predation rates is still insufficient...

  11. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Designation of noxious weeds. 360.200 Section 360.200 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.200 Designation of noxious weeds....

  12. Simple tools and software for precision weed mapping

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple Tools and Software for Precision Weed Mapping L. Wiles If you have a color digital camera and a handheld GPS unit, you can map weed problems in your fields. German researchers are perfecting technology to map weed species and density with digital cameras for precision herbicide application. ...

  13. Seasonal acclimatisation of muscle metabolic enzymes in a reptile (Alligator mississippiensis).

    PubMed

    Seebacher, Frank; Guderley, Helga; Elsey, Ruth M; Trosclair, Phillip L

    2003-04-01

    Reptiles living in heterogeneous thermal environments are often thought to show behavioural thermoregulation or to become inactive when environmental conditions prevent the achievement of preferred body temperatures. By contrast, thermally homogeneous environments preclude behavioural thermoregulation, and ectotherms inhabiting these environments (particularly fish in which branchial respiration requires body temperature to follow water temperature) modify their biochemical capacities in response to long-term seasonal temperature fluctuations. Reptiles may also be active at seasonally varying body temperatures and could, therefore, gain selective advantages from regulating biochemical capacities. Hence, we tested the hypothesis that a reptile (the American alligator Alligator mississippiensis) that experiences pronounced seasonal fluctuations in body temperature will show seasonal acclimatisation in the activity of its metabolic enzymes. We measured body temperatures of alligators in the wild in winter and summer (N=7 alligators in each season), and we collected muscle samples from wild alligators (N=31 in each season) for analysis of metabolic enzyme activity (lactate dehydrogenase, citrate synthase and cytochrome c oxidase). There were significant differences in mean daily body temperatures between winter (15.66+/-0.43 degrees C; mean +/- S.E.M.) and summer (29.34+/-0.21 degrees C), and daily body temperatures fluctuated significantly more in winter compared with summer. Alligators compensated for lower winter temperatures by increasing enzyme activities, and the activities of cytochrome c oxidase and lactate dehydrogenase were significantly greater in winter compared with summer at all assay temperatures. The activity of citrate synthase was significantly greater in the winter samples at the winter body temperature (15 degrees C) but not at the summer body temperature (30 degrees C). The thermal sensitivity (Q(10)) of mitochondrial enzymes decreased

  14. Mechanics of limb bone loading during terrestrial locomotion in the green iguana (Iguana iguana) and American alligator (Alligator mississippiensis).

    PubMed

    Blob, R W; Biewener, A A

    2001-03-01

    In vivo measurements of strain in the femur and tibia of Iguana iguana (Linnaeus) and Alligator mississippiensis (Daudin) have indicated three ways in which limb bone loading in these species differs from patterns observed in most birds and mammals: (i) the limb bones of I. iguana and A. mississippiensis experience substantial torsion, (ii) the limb bones of I. iguana and A. mississippiensis have higher safety factors than those of birds or mammals, and (iii) load magnitudes in the limb bones of A. mississippiensis do not decrease uniformly with the use of a more upright posture. To verify these patterns, and to evaluate the ground and muscle forces that produce them, we collected three-dimensional kinematic and ground reaction force data from subadult I. iguana and A. mississippiensis using a force platform and high-speed video. The results of these force/kinematic studies generally confirm the loading regimes inferred from in vivo strain measurements. The ground reaction force applies a torsional moment to the femur and tibia in both species; for the femur, this moment augments the moment applied by the caudofemoralis muscle, suggesting large torsional stresses. In most cases, safety factors in bending calculated from force/video data are lower than those determined from strain data, but are as high or higher than the safety factors of bird and mammal limb bones in bending. Finally, correlations between limb posture and calculated stress magnitudes in the femur of I. iguana confirm patterns observed during direct bone strain recordings from A. mississippiensis: in more upright steps, tensile stresses on the anterior cortex decrease, but peak compressive stresses on the dorsal cortex increase. Equilibrium analyses indicate that bone stress increases as posture becomes more upright in saurians because the ankle and knee extensor muscles exert greater forces during upright locomotion. If this pattern of increased bone stress with the use of a more upright posture is

  15. Characterization of an EST database for the perennial weed leafy spurge: an important resource for weed biology research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomics programs in the weed science community have not developed as rapidly as that of other crop, horticultural, forestry, and model plant systems. Development of genomic resources for selected model weeds are expected to enhance our understanding of weed biology, just as they have in other plant...

  16. Detecting Weed Infestations in Soybean Using Remote Sensing.

    NASA Astrophysics Data System (ADS)

    Clay, S. A.; Chang, J.; Clay, D. E.; Dalsted, K.; Reese, C.

    2007-12-01

    Can weed distribution maps be developed from remote sensed reflectance data? When are the appropriate times to collect these data during the season? What wavebands can be used to distinguish weedy from weed- free areas? This research examined if and when reflectance could be used to distinguish between weed-free and weed-infested (mixed species) areas in soybean and to determine the most useful wavebands to separate crop, weed, and soil reflectance differences. Treatments in the two-year study included no vegetation (bare soil), weed-free soybean, and weed-infested soybean and, in one year, 80% corn residue cover. Reflectance was measured at several sampling times from May through September in 2001 and 2002 using a hand-held multispectral radiometer equipped with band-limited optical interference filters (460 - 1650 nm). Pixel resolution was 0.8-m. Reflectance in the visible spectral range (460 to 700 nm) generally was similar among treatments. In the near-infrared (NIR) range (>700 to 1650 nm), differences among treatments were observed from soybean growth stage V-3 (about 4 weeks after planting) until mid-July to early August depending on crop vigor and canopy closure (76 cm row spacing in 2001 and 19 cm row spacing in 2002). Reflectance rankings in the NIR range when treatments could be differentiated were consistent between years and, from lowest to highest reflectance, were soil < weed-free < weed-infested areas. Increased reflectance from weed-infested areas was most likely due to increased biomass and canopy cover. Residue masked differences between weed-free and weed- infested areas during the early stages of growth due to high reflectance from the residue and reduced weed numbers in these areas. These results suggest that NIR spectral reflectance collected prior to canopy closure can be used to distinguish weed-infested from weed-free areas.

  17. Virus infection of a weed increases vector attraction to and vector fitness on the weed

    PubMed Central

    Chen, Gong; Pan, Huipeng; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Fang, Yong; Shi, Xiaobin; Zhang, Youjun

    2013-01-01

    Weeds are important in the ecology of field crops, and when crops are harvested, weeds often become the main hosts for plant viruses and their insect vectors. Few studies, however, have examined the relationships between plant viruses, vectors, and weeds. Here, we investigated how infection of the weed Datura stramonium L. by tomato yellow leaf curl virus (TYLCV) affects the host preference and performance of the TYLCV vector, Bemisia tabaci (Gennadius) Q. The results of a choice experiment indicated that B. tabaci Q preferentially settled and oviposited on TYLCV-infected plants rather than on healthy plants. In addition, B. tabaci Q performed better on TYLCV-infected plants than on healthy plants. These results demonstrate that TYLCV is indirectly mutualistic to B. tabaci Q. The mutually beneficial interaction between TYLCV and B. tabaci Q may help explain the concurrent outbreaks of TYLCV and B. tabaci Q in China. PMID:23872717

  18. Contaminants in American alligator eggs from Lake Apopka, Lake Griffin, and Lake Okeechobee, Florida

    USGS Publications Warehouse

    Heinz, G.H.; Percival, H.F.; Jennings, Michael L.

    1991-01-01

    Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and 16 elements were measured in American alligator (Alligator mississippiensis) eggs collected in 1984 from Lakes Apopka, Griffin, and Okeechobee in central and south Florida. Organochlorine pesticides were highest in eggs from Lake Apopka. None of the elements appeared to be present at harmful concentrations in eggs from any of the lakes. A larger sample of eggs was collected in 1985, but only from Lakes Griffin, a lake where eggs were relatively clean, and Apopka, where eggs were most contaminated. In 1985, hatching success of artificially incubated eggs was lower for Lake Apopka, and several organochlorine pesticides were higher than in eggs from Lake Griffin. However, within Lake Apopka, higher levels of pesticides in chemically analyzed eggs were not associated with reduced hatching success of the remaining eggs in the clutch. Therefore, it did not appear that any of the pesticides we measured were responsible for the reduced hatching of Lake Apopka eggs.

  19. Hydrodynamic analysis, performance assessment, and actuator design of a flexible tail propulsor in an artificial alligator

    NASA Astrophysics Data System (ADS)

    Philen, Michael; Neu, Wayne

    2011-09-01

    The overall objective of this research is to develop analysis tools for determining actuator requirements and assessing viable actuator technology for design of a flexible tail propulsor in an artificial alligator. A simple hydrodynamic model that includes both reactive and resistive forces along the tail is proposed and the calculated mean thrust agrees well with conventional estimates of drag. Using the hydrodynamic model forces as an input, studies are performed for an alligator ranging in size from 1 cm to 2 m at swimming speeds of 0.3-1.8 body lengths per second containing five antagonistic pairs of actuators distributed along the length of the tail. Several smart materials are considered for the actuation system, and preliminary analysis results indicate that the acrylic electroactive polymer and the flexible matrix composite actuators are potential artificial muscle technologies for the system.

  20. Determining the size of American alligators using hind-foot track length

    USGS Publications Warehouse

    Wilkinson, Philip M.; Rice, Kenneth G.

    2000-01-01

    Size distribution information is useful for crocodilian management, but can be hard to obtain. Indirect and less costly demographic inferences made from track measurements may be valuable for management decisions. We related hind-foot lengths (HF) with total length (TL) to determine if we could indirectly assess alligator size using track length. Regression showed that HF was an excellent predictor (F1,246= 15722.9, R2=0.98, P<0.01) of TL and track length was an exceptional predictor of HF (F1,14=7520.3, R2= 1.00, P<0.01). The correlation between track length and HF length also was significant (N= 15, r=0.99, P <0.01). Thus, alligator size can be accurately estimated from measures of track length at sites where capture and direct measurement is impractical.

  1. Functional morphology of the Alligator mississippiensis larynx with implications for vocal production.

    PubMed

    Riede, Tobias; Li, Zhiheng; Tokuda, Isao T; Farmer, Colleen G

    2015-04-01

    Sauropsid vocalization is mediated by the syrinx in birds and the larynx in extant reptiles; but whereas avian vocal production has received much attention, the vocal mechanism of basal reptilians is poorly understood. The American alligator (Alligator mississippiensis) displays a large vocal repertoire during mating and in parent-offspring interactions. Although vocal outputs of these behaviors have received some attention, the underlying mechanism of sound production remains speculative. Here, we investigate the laryngeal anatomy of juvenile and adult animals by macroscopic and histological methods. Observations of the cartilaginous framework and associated muscles largely corroborate earlier findings, but one muscle, the cricoarytenoideus, exhibits a heretofore unknown extrinsic insertion that has important implications for effective regulation of vocal fold length and tension. Histological investigation of the larynx revealed a layered vocal fold morphology. The thick lamina propria consists of non-homogenous extracellular matrix containing collagen fibers that are tightly packed below the epithelium but loosely organized deep inside the vocal fold. We found few elastic fibers but comparatively high proportions of hyaluronan. Similar organizational complexity is also seen in mammalian vocal folds and the labia of the avian syrinx: convergent morphologies that suggest analogous mechanisms for sound production. In tensile tests, alligator vocal folds demonstrated a linear stress-strain behavior in the low strain region and nonlinear stress responses at strains larger than 15%, which is similar to mammalian vocal fold tissue. We have integrated morphological and physiological data in a two-mass vocal fold model, providing a systematic description of the possible acoustic space that could be available to an alligator larynx. Mapping actual call production onto possible acoustic space validates the model's predictions. PMID:25657203

  2. Nutrient and organochlorine pesticide concentrations in American alligator eggs and their associations with clutch viability.

    PubMed

    Rauschenberger, R Heath; Sepúlveda, Maria S; Wiebe, Jon J; Wiebe, Janet E; Honeyfield, Dale C; Gross, Timothy S

    2009-12-01

    Since the early 1900s, the lakes of the Ocklawaha basin in central Florida have experienced ecological degradation due to anthropogenic development. One species affected by this degradation is the American alligator Alligator mississippiensis, which has suffered from poor clutch viability and embryo mortality. Although some studies indicate that organochlorine pesticides (OCPs) may be involved, OCPs do not account for all of the variation seen in hatch rates. Indeed, nutrition and non-OCP contaminants have been associated with developmental problems in fish and birds. Our study evaluated embryo mortality in alligators at reference and OCP-contaminated sites as a function of exposure to OCPs, polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs), along with egg nutrients (Zn, Se, and vitamins A, E, and B1). The four-pronged study consisted of a case-control cohort study, an expanded field study, a topical egg treatment thiamine amelioration experiment, and a topical egg treatment thiamine antagonist experiment. The results from the two field studies suggested that the total thiamine levels in the eggs were positively associated with clutch viability and negatively associated with the lipid content and certain OCPs measured in egg yolks. In addition, PCBs, PAHs, Zn, Se, and vitamins A and E were not found to be associated with the observed clutch viability defects. The thiamine levels in the eggs explained 38% of the variation in clutch survival in the case-control cohort study and 27% in the expanded field study. The topical egg treatment experiments were successful in elevating the thiamine concentrations in the albumin but not the yolk. No significant differences were noted among treatment groups in either egg treatment experiment with respect to clutch survival. In summary, thiamine egg concentrations explain some of the variation in the clutch viability of free-ranging alligators, but the cause-effect relationships are still unclear. PMID

  3. WILDLIFE - ALLIGATOR NAMED KASEY LIVES IN POND IN FRONT OF HEADQUARTERS

    NASA Technical Reports Server (NTRS)

    1969-01-01

    A big, toothy saurian grin is flashed by this alligator in the pond in front of the KSC Headquarters Building. And wy not? After years of namelessness, he [or she] has a name. The 'gator was dubbed Kasey following a ''Name the Gator'' contest in which scores of Spaceport employees submitted name suggestions. Kasey is one of two 'gators placed in the pond in an attempt to restore its natural ecology.

  4. Microsatellite DNA analyses support an east-west phylogeographic split of American alligator populations.

    PubMed

    Davis, Lisa M; Glenn, Travis C; Strickland, Denise C; Guillette, Louis J; Elsey, Ruth M; Rhodes, Walter E; Dessauer, Herbert C; Sawyer, Roger H

    2002-12-15

    We examined the population genetic structure of American alligators (Alligator mississippiensis) sampled from 12 localities across the southeastern United States. The primary goal of this study was to determine the extent of population differentiation among alligators from four Florida lakes using eight microsatellite loci and compare the results to additional sites located at varying distances from them. Analyses of population structure revealed little differentiation (F(ST)=0.039; Rho=0.012) among the four Florida lakes, Apopka, Griffin, Orange and Woodruff, which are all located in the St. John&'s River watershed in north-central Florida. Further, there was little differentiation among these samples and samples collected from the Everglades National Park (F(ST)=0.044; Rho=0.009) and south Georgia (F(ST)=0.045; Rho=0.032). Therefore, these six samples were pooled together as a "FL/sGA group." Similarly, samples collected in the western extent of the range, Anahuac National Wildlife Refuge in Texas and Salvador Wildlife Management Area, Marsh Island Wildlife Refuge and Rockefeller Wildlife Refuge in Louisiana, also lacked population structure (F(ST)=0.024; R(ST)=0.040). These four populations were pooled into the "TX/LA group." Comparisons of these two groups with samples taken from the Santee Coastal Reserve in South Carolina and Mobile, Alabama yielded three to four times more differentiation among groups (F(ST)=0.131; Rho=0.187). These and other analyses support the hypothesis of an east-west phylogeographic split in American alligator populations and are consistent with studies of many freshwater fish and aquatic and terrestrial turtles distributed throughout this same geographic region. PMID:12461815

  5. Aminopyralid residue impacts on potatoes and weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminopyralid is used in Alaska to control certain invasive weed species; however it appears to have an extended soil half-life in interior Alaska resulting in carry-over injury in potatoes. Field studies at three experiment stations in Delta Junction, Fairbanks, and Palmer, Alaska were established ...

  6. Diversifying spring wheat systems influences weed community

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed competition constrains dryland crop production in the northern Great Plains. We initiated a field trial in 2004 comparing four crop rotations, with each component in a two-by-two matrix of tillage (conventional vs. zero tillage) and management (conventional vs. ecological) systems. Rotations ...

  7. Weed Research in Alfalfa Seed Production 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in alfalfa seed production is important to produce high quality and high yield of alfalfa seed. Herbicides were tested on a commercial field of alfalfa seed in central Washington in 2007. Flumioxzin slightly injured alfalfa when applied at 0.125 and 0.25 lb ai/a. to dormant alfalfa in M...

  8. Weed Science and Technology. MP-17.

    ERIC Educational Resources Information Center

    Alley, Harold P.; Lee, Gary A.

    This document is one in a series distributed by the Agricultural Extension Service of the University of Wyoming-Laramie. It presents the principles and methods of weed control especially as it relates to the use of herbicides. The factors influencing the effectiveness of both foliar-applied and soil-applied herbicides are discussed. A listing of…

  9. Natural Compounds for Pest and Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The control of insect pests and invasive weeds has become more species-selective because of activity-guided isolation, structure elucidation, and total synthesis of naturally produced substances with important biological activities. Examples of isolated compounds include insect pheromones, antifeed...

  10. Challenges in Weed Management Without Methyl Bromide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl bromide has been used for several decades for pre-plant soil fumigation in high value agricultural and horticultural crops because it can provide broad-spectrum control of insects, nematodes, pathogens, and weeds. However, MeBr has been identified as a powerful ozone-depleting chemical and i...

  11. Acetic acid and weed control in onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a major challenge in conventional and organic production systems, especially for organically produced sweet onion (Allium cepa L.). Although corn gluten meal shows great promise as an organic preemergent herbicide for onions, research has shown the need for supplemental, postemergen...

  12. Bioactive compounds for pest and weed control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The control of insect pests and invasive weeds has become more species-selective because of activity-guided isolation, structure elucidation, and total synthesis of naturally produced substances with important biological activities. Examples of isolated compounds include insect pheromones, antifeed...

  13. Organic weed control in Cowpea: Summer 2006

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea is a major vegetable crop within the state of Oklahoma. It is utilized as both a processing crop by the canning industry and as a fresh market crop for farmer’s and roadside markets. Traditionally weed control in this crop is primarily handled with preemergence and some postemergence herbicid...

  14. Analysis of the landsat remote sensing images of the types of habitats of Yangtze alligators

    NASA Astrophysics Data System (ADS)

    Huang, Zhujian; Lin, Hengzhang; Zhang, Shengkai

    1986-12-01

    The Chinese “Yangtze” alligator is a rare reptile that has been listed as an “endangered species” by the United Nations, so its preservation has become an urgent task. A study of its habitats through analysis of their Landsat images will provide a scientific basis for the government departments concerned to select the best locations for its breeding. The Chinese alligator is a subtropical reptile of freshwater rivers, lakes and ponds. Found only in China, it is now distributed only in the border region between the three provinces of Anhui, Zhejiang and Jiangsu. On the basis of previous investigations by Chinese scientists, and from an analysis and interpretation of their Landsat images, we made a special study, review, and classification of the natural environment of the alligator’s present habitats (and the modern changes in the natural background of these hatitats) so that the government departments concerned with the preservation of the reptiles may have a scientific basis for determining the best locations for the breeding and propagation of the alligator.

  15. Incubation history prior to the canonical thermosensitive period determines sex in the American alligator.

    PubMed

    McCoy, Jessica A; Parrott, Benjamin B; Rainwater, Thomas R; Wilkinson, Phillip M; Guillette, Louis J

    2015-10-01

    Despite the widespread occurrence of environmental sex determination (ESD) among vertebrates, our knowledge of the temporal dynamics by which environmental factors act on this process remains limited. In many reptiles, incubation temperature determines sex during a discrete developmental window just prior to and coincident with the differentiation of the gonads. Yet, there is substantial variation in sex ratios among different clutches of eggs incubated at identical temperatures during this period. Here, we test the hypothesis that temperatures experienced prior to the reported thermosensitive period for alligators (Alligator mississippiensis) can impact how the sex determination system responds to thermal cues later in development. Temperature shift experiments on eggs collected from the field within 24  h of oviposition were employed to decouple various maternal influences from thermal effects, and results demonstrate a previously undefined window of thermosensitivity occurring by stage 15 of embryonic development, six stages earlier than previously reported. We also examine the intrasexual expression of several male- and female-biased genes and show that while male-biased genes display no intrasexual differences, ovarian CYP19A1 (aromatase) transcript abundance differs by approximately twofold depending on thermal exposures experienced at early stages of embryonic development. These findings expand our understanding of the ESD in the alligator and provide the rationale for reevaluation of the temporal dynamics of sex determination in other crocodilians. PMID:26183894

  16. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean.

    PubMed

    Horvath, David P; Hansen, Stephanie A; Moriles-Miller, Janet P; Pierik, Ronald; Yan, Changhui; Clay, David E; Scheffler, Brian; Clay, Sharon A

    2015-07-01

    Weeds reduce yield in soybeans (Glycine max) through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. RNASeq data were collected from six biological samples of soybeans growing with or without weeds. Weed species and the methods to maintain weed-free controls varied between years to mitigate treatment effects, and to allow detection of general soybean weed responses. Soybean plants were not visibly nutrient- or water-stressed. We identified 55 consistently downregulated genes in weedy plots. Many of the downregulated genes were heat shock genes. Fourteen genes were consistently upregulated. Several transcription factors including a PHYTOCHROME INTERACTING FACTOR 3-like gene (PIF3) were included among the upregulated genes. Gene set enrichment analysis indicated roles for increased oxidative stress and jasmonic acid signaling responses during weed stress. The relationship of this weed-induced PIF3 gene to genes involved in shade avoidance responses in Arabidopsis provide evidence that this gene may be important in the response of soybean to weeds. These results suggest that the weed-induced PIF3 gene will be a target for manipulating weed tolerance in soybean. PMID:25711503

  17. Hepatic and renal trace element concentrations in American alligators (Alligator mississippiensis) following chronic dietary exposure to coal fly ash contaminated prey.

    PubMed

    Tuberville, Tracey D; Scott, David E; Metts, Brian S; Finger, John W; Hamilton, Matthew T

    2016-07-01

    Little is known about the propensity of crocodilians to bioaccumulate trace elements as a result of chronic dietary exposure. We exposed 36 juvenile alligators (Alligator mississippiensis) to one of four dietary treatments that varied in the relative frequency of meals containing prey from coal combustion waste (CCW)-contaminated habitats vs. prey from uncontaminated sites, and evaluated tissue residues and growth rates after 12 mo and 25 mo of exposure. Hepatic and renal concentrations of arsenic (As), cadmium (Cd) and selenium (Se) varied significantly among dietary treatment groups in a dose-dependent manner and were higher in kidneys than in livers. Exposure period did not affect Se or As levels but Cd levels were significantly higher after 25 mo than 12 mo of exposure. Kidney As and Se levels were negatively correlated with body size but neither growth rates nor body condition varied significantly among dietary treatment groups. Our study is among the first to experimentally examine bioaccumulation of trace element contaminants in crocodilians as a result of chronic dietary exposure. A combination of field surveys and laboratory experiments will be required to understand the effects of different exposure scenarios on tissue residues, and ultimately link these concentrations with effects on individual health. PMID:27149145

  18. Phyto-synthesis of silver nanoparticles using Alternanthera tenella leaf extract: an effective inhibitor for the migration of human breast adenocarcinoma (MCF-7) cells.

    PubMed

    Sathishkumar, Palanivel; Vennila, Krishnan; Jayakumar, Rajarajeswaran; Yusoff, Abdull Rahim Mohd; Hadibarata, Tony; Palvannan, Thayumanavan

    2016-04-01

    In this study, phyto-synthesis of silver nanoparticles (AgNPs) was achieved using an aqueous leaf extract of Alternanthera tenella. The phytochemical screening results revealed that flavonoids are responsible for the AgNPs formation. The AgNPs were characterised using UV-visible spectrophotometer, field emission scanning microscopy/energy dispersive X-ray, transmission electron microscopy, fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction. The average size of the nanoparticles was found to be ≈48 nm. The EDX results show that strong signals were observed for the silver atoms. The strong band appearing at 1601-1595 cm(-1) correspond to C-C stretching vibration from dienes in FT-IR spectrum indicating the formation of AgNPs. Human breast adenocarcinoma (MCF-7) cells treated with various concentrations of AgNPs showed a dose-dependent increase in cell inhibition. The IC50 value of the AgNPs was calculated to be 42.5 μg mL(-1). The AgNPs showed a significant reduction in the migration of MCF-7 cells. PMID:26801668

  19. Weed management practice selection among Midwest U.S. organic growers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic agricultural systems increase the complexity of weed management, leading organic farmers to cite weeds as the greatest barrier to organic production. Integrated Weed Management (IWM) systems have been developed to address the ecological implications of weeds and weed management in cropping s...

  20. Optical weed detection and evaluation using reflection measurements

    NASA Astrophysics Data System (ADS)

    Vrindts, Els; De Baerdemaeker, Josse

    1999-01-01

    For the site-specific application of herbicides, the automatic detection and evaluation of weeds is necessary. Since reflectance of crop, weeds and soil differs in visual and near IR wavelengths, there is a potential for using reflection measurements at different wavelengths to distinguish between them. Diffuse reflectance spectra of crop and weed leaves were used to evaluate the possibilities of weed detection with reflection measurements. Fourteen different weed species and four crops were included in the dataset. Classification of the spectra in crop, weeds and soil is possible, based on 3 to 7 narrow wavelength bands. The spectral analysis was repeated for reflectance measurements of canopies. Sugarbeet and Maize and 7 weed species were included in the measurements. The classification into crop and weeds was still possible, suing a limited number of wavelength band ratios. This suggest that reflection measurements at a limited number of wavelength bands could be used to detect and treat weeds in a field. This is a great environmental benefit, as agrochemicals will only be used where they are needed. The possibilities of using optical reflectance for weed detection and treatment in the field are discussed.

  1. A non-chemical system for online weed control.

    PubMed

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-01-01

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%-91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide. PMID:25831085

  2. A Non-Chemical System for Online Weed Control

    PubMed Central

    Rueda-Ayala, Victor; Peteinatos, Gerassimos; Gerhards, Roland; Andújar, Dionisio

    2015-01-01

    Non-chemical weed control methods need to be directed towards a site-specific weeding approach, in order to be able to compete the conventional herbicide equivalents. A system for online weed control was developed. It automatically adjusts the tine angle of a harrow and creates different levels of intensity: from gentle to aggressive. Two experimental plots in a maize field were harrowed with two consecutive passes. The plots presented from low to high weed infestation levels. Discriminant capabilities of an ultrasonic sensor were used to determine the crop and weed variability of the field. A controlling unit used ultrasonic readings to adjust the tine angle, producing an appropriate harrowing intensity. Thus, areas with high crop and weed densities were more aggressively harrowed, while areas with lower densities were cultivated with a gentler treatment; areas with very low densities or without weeds were not treated. Although the weed development was relatively advanced and the soil surface was hard, the weed control achieved by the system reached an average of 51% (20%–91%), without causing significant crop damage as a result of harrowing. This system is proposed as a relatively low cost, online, and real-time automatic harrow that improves the weed control efficacy, reduces energy consumption, and avoids the usage of herbicide. PMID:25831085

  3. Laser ablation ICP-MS analysis of the radial distribution of lead in the femur of Alligator mississippiensis.

    PubMed

    Seltzer, Michael D; Lance, Valentine A; Elsey, Ruth M

    2006-06-15

    A laser ablation ICP-MS technique has been used to examine the radial distribution of lead in transverse sections of alligator femur. Annual bone growth in the femur results in the deposition of incremental layers of calcified tissue at the periphery of existing bone. Patterns of lead concentration within these layers provide a record of time-dependent accumulation from which exposure history can potentially be deduced. Femur specimens obtained from captive-reared alligators exhibited levels of lead accumulation that were entirely consistent with previously documented clinical signs of lead intoxication. In contrast, femurs obtained from wild alligators contained only minor amounts of lead that were likely accumulated as a result of incidental exposure. PMID:15982720

  4. Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

    PubMed Central

    Veiga, Rita S. L.; Jansa, Jan; Frossard, Emmanuel; van der Heijden, Marcel G. A.

    2011-01-01

    Background Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. Methodology/Principal Findings First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between −22 and −35%). In a subsequent experiment, we selected three of the negatively responding weed species – Echinochloa crus-galli, Setaria viridis and Solanum nigrum – and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. Conclusions/Significance Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions. PMID

  5. Critical period of weed control in aerobic rice.

    PubMed

    Anwar, M P; Juraimi, A S; Samedani, B; Puteh, A; Man, A

    2012-01-01

    Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7-49 days after seeding in off-season and 7-53 days in main season to achieve 95% of weed-free yield, and 23-40 days in off-season and 21-43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21-43 days for better yield and higher economic return. PMID:22778701

  6. Activity of mesotrione on resistant weeds in maize.

    PubMed

    Sutton, Peter; Richards, Claire; Buren, Larry; Glasgow, Les

    2002-09-01

    Mesotrione is a new callistemone herbicide that inhibits the HPPD enzyme (p-hydroxyphenylpyruvate dioxygenase) and introduces a new naturally selective tool into weed-management programmes for use in maize. Mesotrione provides control of the major broad-leaved weeds, and it can be used in integrated weed-management programmes depending on the grower's preferred weed-control strategy. At post-emergence rates of 150 g AI ha-1 or less, mesotrione provides naturally selective control of key species that may show triazine resistance (TR), e.g. Chenopodium album L, Amaranthus species, Solanum nigrum L, as well as species of weed that show resistance to acetolactase synthase (ALS) inhibitors e.g. Xanthium strumarium L, Amaranthus spp and Sonchus spp. The data presented show that resistant and susceptible biotypes of these species with resistance to triazine herbicides, such as atrazine, simazine, terbutylazine and metribuzin, or ALS-inhibitor herbicides, such as imazethepyr, remain susceptible to mesotrione. These results confirm that there is no cross-resistance in biotypes with target site resistance to triazine or ALS-inhibiting herbicides. It is important that herbicide choice and rotation becomes an integral part of planning weed management, so as to minimise the risks of crop losses from weed competition, build-up of weed seed in the soil and the further development of weed resistance across a range of herbicide modes of action. PMID:12233193

  7. Herbicide-resistant weed management: focus on glyphosate.

    PubMed

    Beckie, Hugh J

    2011-09-01

    This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. PMID:21548004

  8. Full-length cDNA cloning and structural characterization of preproinsulin in Alligator sinensis.

    PubMed

    Zhang, R; Zhang, S Z; Li, E; Wang, C; Wang, C L; Wu, X B

    2014-01-01

    Insulin is an important endocrine hormone that plays a critical physiological role in regulating metabolism and glucostasis in vertebrates. In this study, the complete cDNA of Alligator sinensis preproinsulin gene was cloned for the first time by reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends methods; the amino acid sequence encoded and protein structure were analyzed. The full-length of preproinsulin cDNA sequence consists of 528 base pairs (bp), comprising a 34-bp 5'-untranslated region, a 170-bp 3'-untranslated region and an open reading frame that is 324 bp in length. The open reading frame encodes a 107-amino acid preproinsulin with a molecular weight of approximately 12,153.8 Da, theoretical isoelectric point of 5.68, aliphatic index of 92.06, and grand average of hydropathicity of -0.157, from which a signal peptide, a B-chain, a C-peptide, and an A-chain are derived. Online analysis suggested that the deduced preproinsulin amino acid sequence contains a transmembrane region, and that it has a signal peptide whose cleavage site occurs between alanine 24 and alanine 25. Comparative analysis of preproinsulin amino acid sequences indicated that the A-chain and B-chain sequences of preproinsulins are highly conserved between reptiles and birds, and that the preproinsulin amino acid sequence of Alligator sinensis shares 89% similarity to that of Chelonia mydas, but low similarity of 48-63% to those of mammals and fishes. The phylogenetic tree constructed using the neighbor-joining method revealed that preproinsulin of Alligator sinensis had high homology with reptiles and birds, such as Chelonia mydas, Gallus gallus, and Columba livia. PMID:25366775

  9. Plasma steroid concentrations and male phallus size in juvenile alligators from seven Florida lakes

    USGS Publications Warehouse

    Guillette, L.J., Jr.; Woodward, A.R.; Crain, D.A.; Pickford, D.B.; Rooney, A.A.; Percival, H.F.

    1999-01-01

    Neonatal and juvenile alligators from contaminated Lake Apopka in central Florida exhibit abnormal plasma sex steroid concentrations as well as morphological abnormalities of the gonad and phallus. This study addresses whether similar abnormalities occur in juvenile alligators inhabiting six other lakes in Florida. For analysis, animals were partitioned into two subsets, animals 40-79 cm total length (1-3 years old) and juveniles 80-130 cm total length (3-7 years old). Plasma testosterone (T) concentrations were lower in small males from lakes Apopka, Griffin, and Jessup than from Lake Woodruff National Wildlife Refuge (NWR). Similar differences were observed in the larger juveniles, with males from lakes Jessup, Apopka, and Okeechobee having lower plasma T concentrations than Lake Woodruff males. Plasma estradiol-17?? (E2) concentrations were significantly elevated in larger juvenile males from Lake Apopka compared to Lake Woodruff NWR. When compared to small juvenile females from Lake Woodruff NWR, females from lakes Griffin, Apopka, Orange, and Okeechobee had elevated plasma E2 concentrations. Phallus size was significantly smaller in males from lakes Griffin and Apopka when compared to males from Lake Woodruff NWR. An association existed between body size and phallus size on all lakes except Lake Apopka and between phallus size and plasma T concentration on all lakes except lakes Apopka and Orange. Multiple regression analysis, with body size and plasma T concentration as independent covariables, explained the majority of the variation in phallus size on all lakes. These data suggest that the differences in sex steroids and phallus size observed in alligators from Lake Apopka are not limited to that lake, nor to one with a history of a major pesticide spill. Further work examining the relationship of sex steroids and phallus size with specific biotic and abiotic factors, such as antiandrogenic or estrogenic contaminants, is needed.

  10. DIFFERENCES IN SENSITIVITY BUT NOT SELECTIVITY OF XENOESTROGEN BINDING TO ALLIGATOR VERSUS HUMAN ESTROGEN RECEPTOR ALPHA

    PubMed Central

    Rider, Cynthia V.; Hartig, Phillip C.; Cardon, Mary C.; Lambright, Christy R.; Bobseine, Kathy L.; Guillette, Louis J.; Gray, L. Earl; Wilson, Vickie S.

    2010-01-01

    Reproductive abnormalities in alligators exposed to contaminants in Lake Apopka, Florida, USA represent a clear example of endocrine disruption in wildlife. Several of these contaminants that are not able to bind to mammalian estrogen receptors (such as atrazine and cyanazine) have previously been reported to bind to the alligator estrogen receptor from oviductal tissue. Binding of known Lake Apopka contaminants to full length estrogen receptors alpha from human (hERα) and alligator (aERα) was assessed in a side-by-side comparison within the same assay system. Baculovirus-expressed recombinant hERα and aERα were used in a competitive binding assay. Atrazine and cyanazine were not able to bind to either receptor. p,p′-Dicofol was able to bind to aERα with a concentration inhibiting 50% of binding (IC50) of 4 μM, while only partially displacing 17β-estradiol (E2) from hERα and yielding a projected IC50 of 45 μM. Chemicals that only partially displaced E2 from either receptor, including some dichlorodiphenyltrichloroethane (DDT) metabolites and trans-nonachlor, appeared to have higher affinity for aERα than hERα. p,p′-Dicofol-mediated transcriptional activation through aERα and hERα was assessed to further explore the preferential binding of p,p′-dicofol to aERα over hERα. p,p′-Dicofol was able to stimulate transcriptional activation in a similar manner with both receptors. However, the in vitro results obtained with p,p′-dicofol were not reflected in an in vivo mammalian model, where Kelthane™ (mixed o,p′-and p,p′-dicofol isomers) did not elicit estrogenic effects. In conclusion, although there was no evidence of exclusively species-specific estrogen receptor binders, some xenoestrogens, especially p,p′-dicofol, had a higher affinity for aERα than for hERα. PMID:20821664

  11. Do egg-laying crocodilian (Alligator mississippiensis) archosaurs form medullary bone?

    PubMed

    Schweitzer, M H; Elsey, R M; Dacke, C G; Horner, J R; Lamm, E-T

    2007-04-01

    It is beyond question that Mesozoic dinosaurs, like Aves and Crocodylia, are archosaurs. However, within the archosaurian clade, the origin and distribution of some major features are less clear, particularly with respect to reproductive physiology. Medullary bone, a highly mineralized, bony reproductive tissue present in the endosteal cavities of all extant egg-laying birds thus far examined, has recently been reported in Tyrannosaurus rex. Its presence or absence in extant crocodilians, therefore, may shed light on the timing of its evolutionary appearance. If medullary bone is present in all three taxa, it arose before the three lineages diverged. However, if medullary bone arose after this divergence, it may be present in both extinct dinosaurs and birds, or in birds only. If present in extinct dinosaurs and birds, but not crocodilians, it would indicate that it arose in the common ancestor of this clade, thus adding support to the closer phylogenetic relationship of dinosaurs and birds relative to crocodilians. Thus, the question of whether the crocodilian Alligator mississippiensis forms medullary bone during the production of eggs has important evolutionary significance. Our examination of long bones from several alligators (two alligators with eggs in the oviducts, one that had produced eggs in the past but was not currently in reproductive phase, an immature female and an adult male) shows no differences on the endosteal surfaces of the long bones, and no evidence of medullary bone, supporting the hypothesis that medullary bone first evolved in the dinosaur-bird line, after the divergence of crocodilians from this lineage. PMID:17223615

  12. Physiological response of alligator gar juveniles (Atractosteus spatula) exposed to sub-lethal doses of pollutants.

    PubMed

    González, Carlos Aguilera; Cruz, Julio; Alfaro, Roberto Mendoza

    2015-08-01

    Alligator gar populations have declined because of overfishing, habitat loss and pollution. Over time, the exposure to different pollutants have affected these fishes as a consequence of their high trophic level, bottom-dwelling habits and long life span. In order to evaluate the physiological effects of pollutants on alligator gar, juveniles (6, 12 and 24 months) were exposed to sub-lethal doses of diazinon, β-naphthoflavone (BNF) and 17 β-estradiol (E2) by intraperitoneal injection. After 2 days of exposure, liver samples were taken to determine the activities of acetylcholinesterase, butyrylcholinesterase and carboxylesterase; alkaline and acid phosphatases (ALP and ACP); ethoxyresorufin o-deethylase (EROD); glutathione s-transferase (GST); superoxide dismutase (SOD), and vitellogenin (VTG) concentration. Two additional bioassays consisting on the exposure of compounds through water or food were performed and after 4 and 28 days, respectively, biomarkers were determined. All esterases were inhibited in organisms exposed to diazinon as well as in 6-months gar exposed to E2 and BNF. In contrast, ALP activity increased in gar exposed to diazinon and E2, while ACP activity did not show any variations. No EROD activity was registered after exposure to the different pollutants, despite being one of the most sensitive and common detoxification biomarkers used for fishes. GST activity reduction was detected when gar were exposed to E2 and BNF, while SOD activity increased after exposure to diazinon and E2. Finally, VTG levels were higher in animals exposed to E2 compared to other treatments. Overall, these results suggest that alligator gar juveniles have a low biotransformation metabolism and show that they are especially sensitive to those pollutants affecting the nervous system. PMID:25948055

  13. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina).

    PubMed

    Sirsat, Sarah K G; Sirsat, Tushar S; Price, Edwin R; Dzialowski, Edward M

    2016-01-01

    The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. PMID:26962048

  14. Post-hatching development of mitochondrial function, organ mass and metabolic rate in two ectotherms, the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina)

    PubMed Central

    Sirsat, Sarah K. G.; Sirsat, Tushar S.; Price, Edwin R.; Dzialowski, Edward M.

    2016-01-01

    ABSTRACT The ontogeny of endothermy in birds is associated with disproportionate growth of thermogenic organs and increased mitochondrial oxidative capacity. However, no similar study has been made of the development of these traits in ectotherms. For comparison, we therefore investigated the metabolism, growth and muscle mitochondrial function in hatchlings of a turtle and a crocodilian, two ectotherms that never develop endothermy. Metabolic rate did not increase substantially in either species by 30 days post-hatching. Yolk-free body mass and heart mass did not change through 30 days in alligators and heart mass was a constant proportion of body mass, even after 1 year. Yolk-free body mass and liver mass grew 36% and 27%, respectively, in turtles during the first 30 days post-hatch. The mass-specific oxidative phosphorylation capacity of mitochondria, assessed using permeabilized muscle fibers, increased by a non-significant 47% in alligator thigh and a non-significant 50% in turtle thigh over 30 days, but did not increase in the heart. This developmental trajectory of mitochondrial function is slower and shallower than that previously observed in ducks, which demonstrate a 90% increase in mass-specific oxidative phosphorylation capacity in thigh muscles over just a few days, a 60% increase in mass-specific oxidative phosphorylation capacity of the heart over a few days, and disproportionate growth of the heart and other organs. Our data thus support the hypothesis that these developmental changes in ducks represent mechanistic drivers for attaining endothermy. PMID:26962048

  15. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    NASA Astrophysics Data System (ADS)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  16. Characterization of microsatellite DNA markers for the alligator snapping turtle, Macrochelys temminckii: Primer note

    USGS Publications Warehouse

    Hackler, J.C.; Van Den Bussche, Ronald A.; Leslie, David M., Jr.

    2007-01-01

    Two trinucleotide and seven tetranucleotide microsatellite loci were isolated from an alligator snapping turtle Macrochelys temminckii. To assess the degree of variability in these nine microsatellite loci, we genotyped 174 individuals collected from eight river drainage basins in the southeastern USA. These markers revealed a moderate degree of allelic diversity (six to 16 alleles per locus) and observed heterozygosity (0.166-0.686). These polymorphic microsatellite loci provide powerful tools for population genetic studies for a species that is afforded some level of conservation protection in every state in which it occurs. ?? 2006 The Authors.

  17. Herbicide Resistant Weeds: Do Economic Thresholds Still Have a Role in Weed Management?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concern over the development of herbicide resistant weeds has prompted a closer look at the validity of using economic thresholds (ET) as a basis for making treatment decisions. In situations where herbicide resistance is suspected, growers are often advised to employ control measures to completely ...

  18. SURVEY OF WEEDS AND WEED MANAGEMENT IN SWEET CORN GROWN FOR PROCESSING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The north-central United States produces approximately one-half of sweet corn grown for processing, predominantly in Illinois, Minnesota, and Wisconsin. Improved weed management systems for sweet corn are desired greatly by growers, processors, and the seed industry; however, information on problem...

  19. Urinary iodine and stable isotope analysis to examine habitat influences on thyroid hormones among coastal dwelling American alligators.

    PubMed

    Boggs, Ashley S P; Hamlin, Heather J; Nifong, James C; Kassim, Brittany L; Lowers, Russell H; Galligan, Thomas M; Long, Stephen E; Guillette, Louis J

    2016-01-15

    The American alligator, generally a freshwater species, is known to forage in marine environments despite the lack of a salt secreting gland found in other crocodylids. Estuarine and marine foraging could lead to increased dietary uptake of iodine, a nutrient necessary for the production of thyroid hormones. To explore the influence of dietary iodine on thyroid hormone health of coastal dwelling alligators, we described the seasonal plasma thyroxine and triiodothyronine concentrations measured by radioimmunoassay and urinary iodine (UI) concentrations measured by inductively coupled plasma mass spectrometry. We also analyzed long-term dietary patterns through stable isotope analysis of scute tissue. Snout-to-vent length (SVL) was a significant factor among UI and stable isotope analyses. Large adult males greater than 135cm SVL had the highest UI concentrations but did not display seasonality of thyroid hormones. Alligators under 135 SVL exhibited seasonality in thyroid hormones and a positive relationship between UI and triiodothyronine concentrations. Isotopic signatures provided supporting evidence that large males predominantly feed on marine/estuarine prey whereas females showed reliance on freshwater/terrestrial prey supplemented by marine/estuarine prey. UI measurement provided immediate information that correlated to thyroid hormone concentrations whereas stable isotope analysis described long-term dietary patterns. Both techniques demonstrate that adult alligators in coastal environments are utilizing estuarine/marine habitats, which could alter thyroid hormone physiology. PMID:26684734

  20. The first fossil skull of Alligator sinensis from the Pleistocene, Taiwan, with a paleogeographic implication of the species

    NASA Astrophysics Data System (ADS)

    Hsi-yin, Shan; Yen-nien, Cheng; Xiao-chun, Wu

    2013-06-01

    A nearly complete fossil skull of Alligatoridae from the Pleistocene, Penghu Channel, east of Taiwan, is reported. It can be referred to the most latest clade of Alligatorinae, which includes Alligator sinensis, Alligator mississippiensis and Alligator mefferdi, on the basis of the following features: the splenial is excluded from the mandibular symphysis; the anterior tip of the splenial passes dorsal to the Meckelian groove; and the mandible is gently curved between the fourth alveoli and the mid dentary. It differs from A. mississippiensis and A. mefferdi mainly in the following characters: the breadth between the supratemporal fenestrae is approximately equal to the interorbital width, the snout is about half the length of the skull; and the anterior part of the snout is subtriangular in dorsal view. These features suggest that the Penghu alligator is most probably referable to A. sinensis. This is the only fossil skull of A. sinensis known. The discovery of the skull in Penghu Channel not only provides the first solid fossil evidence to indicate that the geological distribution of A. sinensis extended farther southeast than the historical/archeological range of the species but also adds new information on the biodiversity of the Penghu fauna.

  1. Slow isotope turnover rates and low discrimination values in the American alligator: implications for interpretation of ectotherm stable isotope data.

    PubMed

    Rosenblatt, Adam E; Heithaus, Michael R

    2013-01-01

    Stable isotope analysis has become a standard ecological tool for elucidating feeding relationships of organisms and determining food web structure and connectivity. There remain important questions concerning rates at which stable isotope values are incorporated into tissues (turnover rates) and the change in isotope value between a tissue and a food source (discrimination values). These gaps in our understanding necessitate experimental studies to adequately interpret field data. Tissue turnover rates and discrimination values vary among species and have been investigated in a broad array of taxa. However, little attention has been paid to ectothermic top predators in this regard. We quantified the turnover rates and discrimination values for three tissues (scutes, red blood cells, and plasma) in American alligators (Alligator mississippiensis). Plasma turned over faster than scutes or red blood cells, but turnover rates of all three tissues were very slow in comparison to those in endothermic species. Alligator δ(15)N discrimination values were surprisingly low in comparison to those of other top predators and varied between experimental and control alligators. The variability of δ(15)N discrimination values highlights the difficulties in using δ(15)N to assign absolute and possibly even relative trophic levels in field studies. Our results suggest that interpreting stable isotope data based on parameter estimates from other species can be problematic and that large ectothermic tetrapod tissues may be characterized by unique stable isotope dynamics relative to species occupying lower trophic levels and endothermic tetrapods. PMID:23303328

  2. Weed Seedling Emergence and Survival as Affected by Crop Canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study measured impact of cool-season crops on seedling emergence, survival, and seed production of weeds common in corn and soybean. Weed dynamics were monitored in permanently-marked quadrats in winter wheat, spring wheat, and canola. Three species, green foxtail, yellow foxtail, and common ...

  3. Third season weed control in blackberries using synthetic ground covers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic weed barriers, which have shown promise in a first fruiting season ‘Kiowa’ blackberry (Rubus spp) planting (near Monte Alto, TX; Lat. 26º 26’N), were evaluated for a second fruiting season in 2008. Weed removal times were significantly shorter and material integrity unaffected by time (Ma...

  4. Corn gluten meal for weed control in cowpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea, a major crop in Oklahoma, is produced for the fresh market and canning industry. Synthetic preemergence and postemergence herbicides are the primary weed control method in conventional (non-organic) production systems. Organic weed control in organic cowpea production includes obstacles wh...

  5. Weed resistance challenges and management under herbicide resistant cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last six decades, herbicides have been the mainstay of weed management in cropping systems around the world, especially in the Western Hemisphere. A direct consequence of intensive use of herbicides is the development of resistance in weed populations. The extreme popularity of transgenic g...

  6. Managing weeds in organic farming systems: an ecological approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous investigators have concluded that improvements in weed management strategies that are minimally reliant on herbicides require the integration of multiple weed suppression tactics. However, the most cost-effective and efficacious ways to choose and combine tactics remain unclear. Here we sug...

  7. Post-directed weed control in bell peppers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic pepper (Capsicum annuum L.) producers need appropriate herbicides that can effectively provide post-emergent weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of a potential organic herbicide on weed control efficacy, crop injury, an...

  8. Molecular Biology and Genomics: New Tools for Weed Science

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain plant species are particularly well adapted to environments disturbed by humans. Often such species are invasive and problematic, and thus are classified as weeds. Despite our best efforts to control weeds, they continue to interfere with crop production. Clearly there is much to learn about...

  9. Impact of weed barriers on newly planted peach trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newly planted (Feb. 2005) ‘Sunracer’ and ‘Sunhome’ nectarine and ‘Tropic Snow’ peach (Prunus persica (L.) Batsch) trees were subjected to conventional and four 'organic' weed control methods. Two of the 'organic' methods used weed barriers of white plastic (WP) or landscape fabric (LF). A third co...

  10. Weed management using goats: Effects on water infiltration rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Goats are used increasingly for weed control, fire fuel reduction and ecological restoration. The high stocking rates typical of these applications have been reported to decrease the rate of water infiltration in goat pastures. The hypothesis that annual goat browsing for weed control decreases infi...

  11. Using Mustard Seed Meal and Cover Crops for Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There continues to be a steady growth in the use of fall planted brassica cover crops in the Columbia Basin especially prior to potatoes. Several benefits include better water infiltration, reclaiming nitrogen, reduced erosion, and suppression of nematodes, diseases, and weeds. Weed suppression is...

  12. Susceptibility of some common container weeds to Phytophthora ramorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytophthora ramorum is known to infect a number of ornamental plants grown in containerized culture. However, pots may also contain weeds. In this research, the foliage of 13 common weeds of containerized plant culture was inoculated with Phytophthora ramorum to determine susceptibility of above-...

  13. Herbicide-resistant crops, resistant weeds, and herbicide drift

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New herbicide-resistance traits in corn and soybean may bring new management challenges for fruit and vegetable growers in the Mid-Atlantic region. Herbicide-resistant crops are an important weed management technology in row crop agriculture that allow growers to apply an herbicide to control weed...

  14. The Importance of Intertrophic Interactions in Biological Weed Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The earliest research leading to successful weed biocontrol included observations and some analysis that the strict “gate-keeping” by peer reviewers, editors and publishers does not often allow today. Within these pioneering studies was a valid picture of the biology of weed biocontrol that is appli...

  15. Weed manipulation for insect pest management in corn

    NASA Astrophysics Data System (ADS)

    Altieri, M. A.; Whitcomb, W. H.

    1980-11-01

    Populations of insect pests and associated predaceous arthropods were sampled by direct observation and other relative methods in simple and diversified corn habitats at two sites in north Florida during 1978 and 1979. Through various cultural manipulations, characteristic weed communities were established selectively in alternate rows within corn plots. Fall armyworm ( Spodoptera frugiperda J. E. Smith) incidence was consistently higher in the weed-free habitats than in the corn habitats containing natural weed complexes or selected weed associations. Corn earworm ( Heliothis zea Boddie) damage was similar in all weed-free and weedy treatments, suggesting that this insect is not affected greatly by weed diversity. Only the diversification of corn with a strip of soybean significantly reduced corn earworm damage. In one site, distance between plots was reduced. Because predators moved freely between habitats, it was difficult to identify between-treatment differences in the composition of predator communities. In the other site, increased distances between plots minimized such migrations, resulting in greater population densities and diversity of common foliage insect predators in the weed-manipulated corn systems than in the weed-free plots. Trophic relationships in the weedy habitats were more complex than food webs in monocultures. Predator diversity (measured as mean number of species per area) and predator density was higher in com plots surrounded by mature, complex vegetation than at those surrounded by annual crops. This suggests that diverse adjacent areas to crops provide refuge for predators, thus acting as colonization sources.

  16. Organic weed control with vinegar: Application volumes and adjuvants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Preliminary results have indicated that vinegar has potential as an organic herbicide, but further research is needed to increase our understanding of the relationship between acetic acid concentrations, application volumes, adjuvants, weed species, and weed maturity on effectiveness of vinegar to c...

  17. Use of synthetic ground covers to control weeds in blackberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in blackberries (Rubus spp.) is a serious problem for organic producers and those who wish to reduce their reliance on herbicides. Three landscape fabrics (Dewitt, Texel, and a white polyester weave) and one industrial grade white on black plastic were used for weed control in conjucti...

  18. 7 CFR 360.200 - Designation of noxious weeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Aquatic and wetland weeds: Azolla pinnata R. Brown (mosquito fern, water velvet) Caulerpa taxifolia...-reed) (b) Parasitic weeds: Aeginetia spp. Alectra spp. Cuscuta spp. (dodders), other than following... vetchii Brandegee Cuscuta warneri Yuncker Orobanche spp. (broomrapes), other than the following...

  19. Organic weed management in vegetables: Research, experiences, and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic farmers in a national survey ranked weed management as their greatest research need for organic crop production. Scientists from the Agriculture Research Service and Oklahoma State University have combined their efforts to conduct not only organic weed control research, but research involvi...

  20. Emerging Technologies: An Opportunity for Weed Biology Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The main objective of the Emerging Technologies Symposium at the 2007 WSSA Annual Meeting was to provide the weed science community with the principles behind emerging technologies and how they can be used to study weed biology. Specifically, aspects and applications related to genomic database deve...

  1. Weeds of the Midwestern United States and Central Canada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The book, Weeds of the Central United States and Canada, includes 356 of the most common and/or troublesome weeds of agricultural and natural areas found within the central region of the United States and Canada. The books includes an introduction, a key to plant families contained in the book, glo...

  2. How to Identify and Control Water Weeds and Algae.

    ERIC Educational Resources Information Center

    Applied Biochemists, Inc., Mequon, WI.

    Included in this guide to water management are general descriptions of algae, toxic algae, weed problems in lakes, ponds, and canals, and general discussions of mechanical, biological and chemical control methods. In addition, pictures, descriptions, and recommended control methods are given for algae, 6 types of floating weeds, 18 types of…

  3. Working the Educational Soil and Pulling Up Weeds

    ERIC Educational Resources Information Center

    Riggins-Newby, Cheryl

    2005-01-01

    The job of an instructional leader, according to former Baltimore principal Deborah Wortham, is to be a gardener. School cultures left unattended, she says, sprout weeds that will eventually overwhelm the research-based programs, practices, and best efforts of teachers and administrators. The most aggressive and harmful educational weeds Wortham…

  4. 'Carolina' session: a major utilities program to manage aquatic weeds

    SciTech Connect

    Schiller, D.H.

    1984-06-01

    Carolina Power and Light Company has recently experienced aquatic weed problems in two of its impoundments. These problems have impacted power plant operations, water quality, and recreational activities. The Company is actively pursuing a program to deal with these weed problems through education, research, monitoring, and control activities.

  5. Mapping riparian and wetland weeds with high resolution satellite imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic and wetland weeds are a serious management problem in many freshwater ecosystems of the world. This paper presents an overview on the application of using high resolution QuickBird multi-spectral satellite imagery for detecting weeds in waterways and wetlands in Texas. Unsupervised image a...

  6. Weed science research and funding: a call to action

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed science has contributed much to agriculture, forestry and natural resource management over its history. However, if it is to remain relevant as a scientific discipline, it is long past time for weed scientists to take a step outside the “herbicide efficacy box” and address system-level issues i...

  7. Spectral reflectance and digital image relations among five aquatic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports on the use of an artificial quartz halogen lighting source to facilitate the acquisition of spectral light reflectance measurements and digital imaging of invasive aquatic weeds. Spectral leaf or leaf/stem reflectance measurements were made on five aquatic weeds: Eurasian watermil...

  8. Mapping Invasive Aquatic and Wetland Weeds with Quickbird Satellite Imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic and wetland weeds are a serious management problem in many freshwater ecosystems of the world. This paper presents an overview on the application of using high resolution QuickBird multi-spectral satellite imagery for detecting weeds in waterways and wetlands in Texas. Unsupervised image a...

  9. Crop diversity sequencing can improve crop tolerance to weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The corn-soybean rotation in eastern South Dakota has led to a weed community comprised of species with similar life cycles to the crops; subsequently, weed management is a major input cost for producers. We are exploring crop diversity in this rotation to determine if producers can reduce the need...

  10. Cultivation strategies for weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed management in organic peanut production is difficult and costly. Previous research demonstrated limitations of propane flaming and OMRI-approved herbicides suitable use in organic production. Furthermore, related studies clearly showed the inability to manage weeds in reduced-tillage organic ...

  11. Weed Community Emergence Pattern in Eastern South Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers who followed rotations comprised of crops with different growth periods are able to manage weeds with less herbicides. The diversity in growth periods provides more opportunities for producers to prevent weed seed production. In our research program, we are exploring impact of cool-seaso...

  12. Site-Specific Weed Management: Myth or Magic?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific weed management (SSWM) is a potential method to reduce the risks of herbicide use on water quality and public health without impacting crop yield. With site-specific weed management, areas of the field are left untreated where control is not economically justified. Where control is nee...

  13. Potential components for weed management in organic vegetable production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic vegetable production relies on a variety of tactics for preventing losses to crop yield and quality that result from weed interference. These include field selection, long term field management, cultivation practices, mulching, and manual weeding to name a few. The concept of "herbicides" th...

  14. Corn gluten meal: Weed control and yields for onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One weed control option for certified organic producers is corn gluten meal (CGM). Field research was conducted in southeast Oklahoma (Lane, OK) to determine the efficacy of CGM as an herbicide for use in transplanted onion production. The research involved 8 weed control treatments with 4 replicat...

  15. Letting Go: How One Librarian Weeded a Children's Magazine Collection.

    ERIC Educational Resources Information Center

    Bromann, Jennifer

    2002-01-01

    Describes the weeding process for children's magazines in a public library. Highlights include circulation statistics; cost effectiveness; online availability; shelving magazines by subject to try and increase their use; and a chart that lists reasons to keep and reasons to cancel subscriptions when weeding a periodical collection. (LRW)

  16. Perpendicular cultivation for improved weed control in organic peanut production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive cultivation in organic peanut is partially effective, but in-row weed control remains problematic. In an attempt to improve in-row weed control, trials were conducted to determine the feasibility of early-season cultivation perpendicular to row direction using a tine weeder when integrate...

  17. Evaluation of corn gluten meal for weed control in cowpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current weed control practices for cowpea production typically involve use of synthetic herbicides. Increasing interest in organic crop production creates a need for alternative weed control techniques that are consistent with requirements of the USDA National Organic Program. Corn gluten meal (CG...

  18. Use of cryptic species for biological control of weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Classical biological control of weeds depends on the discovery and evaluation of species of arthropods that are highly host specific. The rarity of such species in nature limits our ability to find safe effective agents to control a continually increasing list of invasive alien weeds. However, sci...

  19. Weed Suppression by Seven Clover Species

    SciTech Connect

    Ross, Shirley M.; King, Jane R.; Izaurralde, R Cesar C.; O'Donovan, John T.

    2001-01-01

    Used as cover crops, clover species may differ in their ability to suppress weed growth. Field trials were conducted in Alberta, Canada to measure the growth of brown mustard [Brassica juncea (L.) Czern.], in mowed and nonmowed production, as influenced by alsike (Trifolium hybridum L.), balansa [T. michelianum Savi var. balansae (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson [T. incarnatum (Boiss.) Azn.], berseem (T. alexandrinum L.), crimson (T. incarnatum L.), Persian (T. resupinatum L.), red (T. pratense L.), and white Dutch (T. repens L.) clover and fall rye (Secale cereale L.). In 1997, clovers reduced mustard biomass in nonmowed treatments by 29% on a high- fertility soil (Typic Cryoboroll) at Edmonton and by 57% on a low- fertility soil (Typic Cryoboralf) at Breton. At Edmonton, nonmowed mustard biomass was reduced by alsike and berseem clover in 1996 and by alsike, balansa, berseem, and crimson clover in 1997. At Breton, all seven clover species suppressed weed biomass. A negative correlation was noted among clover and mustard biomass at Edmonton but not at Breton. The effects of mowing varied with location, timing, and species. Mowing was beneficial to crop/weed proportion at Edmonton but not at Breton. Mowing at early flowering of mustard large-seeded legumes and sweetclover (Melilotus offici) produced greater benefit than mowing at late flowering. With early mowing, all clover species suppressed mustard growth at Edmonton. Clovers reduced mustard regrowth (g plant21 ) and the number of mustard plants producing regrowth. The characteristics of berseem clover (upright growth, long stems, high biomass, and late flowering) would support its use as a cover crop or forage in north-central Alberta.

  20. Potential impact of Dare County landfills on Alligator River National Wildlife Refuge

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.; Augspurger, T.

    2005-01-01

    Runoff of leachate from East Lake and Dare County Construction and Demolition Debris landfills has the potential to impact wildlife resources at Alligator River National Wildlife Refuge, Dare and Hyde Counties, North Carolina. Sediment quality of samples collected in August 2000 at 14 locations down-gradient from the landfills was assessed by measuring metal and organic contaminants in the sediments, chronic toxicity of solid-phase sediment (28-d static-renewal exposures; survival and growth as test endpoints) and acute toxicity of sediment porewater (96-h static exposures) to Hyalella azteca (Crustacea: Amphipoda). In addition, contaminant bioaccumulation from 4 sediments was determined using 28-d exposures of Lumbriculus variegatus (freshwater oligochaete). Although survival was not impaired, length of H. azteca was significantly reduced in sediments from 5 locations. Pore water from 4 locations was acutely toxic to H. azteca. Metals and a few polycyclic aromatic hydrocarbons (PAHs) were bioaccumulated by L. variegatus from the sediments. Several metals and PAHs exceeded sediment quality guidelines, and metals in porewater from several sites exceeded water quality criteria for the protection of aquatic wildlife. Runoff of leachate from the landfills has reduced sediment quality and has the potential to adversely affect wildlife resources at Alligator River National Wildlife Refuge.

  1. Quantification of intraskeletal histovariability in Alligator mississippiensis and implications for vertebrate osteohistology

    PubMed Central

    Horner, John R.; Farlow, James O.

    2014-01-01

    Bone microanalyses of extant vertebrates provide a necessary framework from which to form hypotheses regarding the growth and skeletochronology of extinct taxa. Here, we describe the bone microstructure and quantify the histovariability of appendicular elements and osteoderms from three juvenile American alligators (Alligator mississippiensis) to assess growth mark and tissue organization within and amongst individuals, with the intention of validating paleohistological interpretations. Results confirm previous observations that lamellar and parallel fibered tissue organization are typical of crocodylians, and also that crocodylians are capable of forming woven tissue for brief periods. Tissue organization and growth mark count varies across individual skeletal elements and reveal that the femur, tibia, and humerus had the highest annual apposition rates in each individual. Cyclical growth mark count also varies intraskeletally, but data suggest these inconsistencies are due to differing medullary cavity expansion rates. There was no appreciable difference in either diaphyseal circumference or cyclical growth mark circumferences between left and right element pairs from an individual if diaphyses were sampled from roughly the same location. The considerable intraskeletal data obtained here provide validation for long-held paleohistology assumptions, but because medullary expansion, cyclical growth mark formation, and variable intraskeletal growth rates are skeletal features found in tetrapod taxa living or extinct, the validations presented herein should be considered during any tetrapod bone microanalysis. PMID:24949239

  2. Trigeminal nerve morphology in Alligator mississippiensis and its significance for crocodyliform facial sensation and evolution.

    PubMed

    George, Ian D; Holliday, Casey M

    2013-04-01

    Modern crocodylians possess a derived sense of face touch, in which numerous trigeminal nerve-innervated dome pressure receptors speckle the face and mandible and sense mechanical stimuli. However, the morphological features of this system are not well known, and it remains unclear how the trigeminal system changes during ontogeny and how it scales with other cranial structures. Finally, when this system evolved within crocodyliforms remains a mystery. Thus, new morphological insights into the trigeminal system of extant crocodylians may offer new paleontological tools to investigate this evolutionary transformation. A cross-sectional study integrating histological, morphometric, and 3D imaging analyses was conducted to identify patterns in cranial nervous and bony structures of Alligator mississippiensis. Nine individuals from a broad size range were CT-scanned followed by histomorphometric sampling of mandibular and maxillary nerve divisions of the trigeminal nerve. Endocast volume, trigeminal fossa volume, and maxillomandibular foramen size were compared with axon counts from proximal and distal regions of the trigeminal nerves to identify scaling properties of the structures. The trigeminal fossa has a significant positive correlation with skull length and endocast volume. We also found that axon density is greater in smaller alligators and total axon count has a significant negative correlation with skull size. Six additional extant and fossil crocodyliforms were included in a supplementary scaling analysis, which found that size was not an accurate predictor of trigeminal anatomy. This suggests that phylogeny or somatosensory adaptations may be responsible for the variation in trigeminal ganglion and nerve size in crocodyliforms. PMID:23408584

  3. Quantification of intraskeletal histovariability in Alligator mississippiensis and implications for vertebrate osteohistology.

    PubMed

    Woodward, Holly N; Horner, John R; Farlow, James O

    2014-01-01

    Bone microanalyses of extant vertebrates provide a necessary framework from which to form hypotheses regarding the growth and skeletochronology of extinct taxa. Here, we describe the bone microstructure and quantify the histovariability of appendicular elements and osteoderms from three juvenile American alligators (Alligator mississippiensis) to assess growth mark and tissue organization within and amongst individuals, with the intention of validating paleohistological interpretations. Results confirm previous observations that lamellar and parallel fibered tissue organization are typical of crocodylians, and also that crocodylians are capable of forming woven tissue for brief periods. Tissue organization and growth mark count varies across individual skeletal elements and reveal that the femur, tibia, and humerus had the highest annual apposition rates in each individual. Cyclical growth mark count also varies intraskeletally, but data suggest these inconsistencies are due to differing medullary cavity expansion rates. There was no appreciable difference in either diaphyseal circumference or cyclical growth mark circumferences between left and right element pairs from an individual if diaphyses were sampled from roughly the same location. The considerable intraskeletal data obtained here provide validation for long-held paleohistology assumptions, but because medullary expansion, cyclical growth mark formation, and variable intraskeletal growth rates are skeletal features found in tetrapod taxa living or extinct, the validations presented herein should be considered during any tetrapod bone microanalysis. PMID:24949239

  4. Voltage oscillations and ionic conductances in hair cells isolated from the alligator cochlea.

    PubMed

    Fuchs, P A; Evans, M G

    1988-12-01

    Tall hair cells were isolated by enzymatic and mechanical dissociation from selected regions of the apical half of the alligator (A. mississippiensis) cochlea. Single cells were subjected to voltage-clamp and current-clamp using the tight-seal whole-cell recording technique. Most hair cells isolated from the apex of the cochlea produced slowly regenerative depolarizations or Na action potentials during current injection, whereas hair cells isolated from more basal regions usually produced voltage oscillations (ringing) in response to depolarizing current injection, an indication of electrical resonance. Resonant frequencies ranged from 50 to 157 Hz in different cells. The higher-frequency cells tended to have larger and more rapidly activating outward currents than did the lower-frequency cells. An inward Ca current and an outward Ca-activated K current were present in all hair cells. In addition, an inwardly rectifying current and a small, transient outward current were often seen. Thus, we conclude that an electrical tuning mechanism is present in alligator hair cells. The role of the ionic conductances in shaping hair cell responses to current injection, and the possible contributions of these electrical responses to cochlear function are discussed. PMID:3244125

  5. Three-dimensional skeletal kinematics of the shoulder girdle and forelimb in walking Alligator

    PubMed Central

    Baier, David B; Gatesy, Stephen M

    2013-01-01

    Crocodylians occupy a key phylogenetic position for investigations of archosaur locomotor evolution. Compared to the well-studied hindlimb, relatively little is known about the skeletal movements and mechanics of the forelimb. In this study, we employed manual markerless XROMM (X-ray Reconstruction Of Moving Morphology) to measure detailed 3-D kinematics of the shoulder girdle and forelimb bones of American alligators (Alligator mississippiensis) walking on a treadmill. Digital models of the interclavicle, scapulocoracoid, humerus, radius and ulna were created using a 3-D laser scanner. Models were articulated and aligned to simultaneously recorded frames of fluoroscopic and standard light video to reconstruct and measure joint motion. Joint coordinate systems were established for the coracosternal, glenohumeral and elbow joints. Our analysis revealed that the limb joints only account for about half of fore/aft limb excursion; the remaining excursion results from shoulder girdle movements and lateral bending of the vertebral column. Considerable motion of each scapulocoracoid relative to the vertebral column is consistent with coracosternal mobility. The hemisellar design of the glenohumeral joint permits some additional translation, or sliding in the fore-aft plane, but this movement does not have much of an effect on the distal excursion of the bone. PMID:24102540

  6. Histological organization and its relationship to function in the femur of Alligator mississippiensis

    PubMed Central

    Lee, Andrew H

    2004-01-01

    Histological analysis of a growth series of alligator femora tests the correlation between strain milieu and microstructure. From mid-diaphyseal cross-sections of these femora (n = 7), vascular canal orientation and density as well as collagen fibre organization were recorded. Throughout ontogeny, the proportion of transverse–spiral (TS) collagen in the dorsal cortex is significantly greater than it is in the ventral cortex (P = 0.008). This regional difference in the proportion of TS collagen is correlated with a regional difference in the state of peak principal strain (compressive or tensile). Nevertheless, the predominant orientation of collagen fibres is longitudinal, which is inconsistent with biomechanical hypotheses that involve peak principal or shear strains. Although the density and orientation of vascular canals do not show significant regional differences (P = 0.26 and P = 0.26, respectively), as with collagen orientation, the vascular canal orientation is predominantly longitudinal. The longitudinal organization of both the vascular canals and the collagen fibres is probably a consequence of longitudinal shifting of subperiosteal osteoid during femoral lengthening. When taken together, these data suggest that growth dynamics is the dominant influence on the histological organization of primary bony tissues in alligator femora. PMID:15032909

  7. In vivo bone strain and finite element modeling of the mandible of Alligator mississippiensis

    PubMed Central

    Porro, Laura B; Metzger, Keith A; Iriarte-Diaz, Jose; Ross, Callum F

    2013-01-01

    Forces experienced during feeding are thought to strongly influence the morphology of the vertebrate mandible; in vivo strain data are the most direct evidence for deformation of the mandible induced by these loading regimes. Although many studies have documented bone strains in the mammalian mandible, no information is available on strain magnitudes, orientations or patterns in the sauropsid lower jaw during feeding. Furthermore, strain gage experiments record the mechanical response of bone at a few locations, not across the entire mandible. In this paper, we present bone strain data recorded at various sites on the lower jaw of Alligator mississippiensis during in vivo feeding experiments. These data are used to understand how changes in loading regime associated with changes in bite location are related to changes in strain regime on the working and balancing sides of the mandible. Our results suggest that the working side mandible is bent dorsoventrally and twisted about its long-axis during biting, and the balancing side experiences primarily dorsoventral bending. Strain orientations are more variable on the working side than on the balancing side with changes in bite point and between experiments; the balancing side exhibits higher strain magnitudes. In the second part of this paper, we use principal strain orientations and magnitudes recorded in vivo to evaluate a finite element model of the alligator mandible. Our comparison demonstrates that strain orientations and mandibular deformation predicted by the model closely match in vivo results; however, absolute strain magnitudes are lower in the finite element model. PMID:23855772

  8. Hyperspectral image sensor for weed-selective spraying

    NASA Astrophysics Data System (ADS)

    Feyaerts, Filip; Pollet, P.; Van Gool, Luc J.; Wambacq, Patrick

    1999-11-01

    Recognizing, online, cops and weeds enables to reduce the use of chemicals in agriculture. First, a sensor and classifier is proposed to measure and classify, online, the plant reflectance. However, as plant reflectance varies with unknown field dependent plant stress factors, the classifier must be trained on each field separately in order to recognize crop and weeds accurately on that field. Collecting the samples manually requires user-knowledge and time and is therefore economically not feasible. The posed tree-based cluster algorithm enables to automatically collect and label the necessary set of training samples for crops that are planted in rows, thus eliminating every user- interaction and user-knowledge. The classifier, trained with the automatically collected and labeled training samples, is able to recognize crop and weeds with an accuracy of almost 94 percent. This result in acceptable weed hit rates and significant herbicide reductions. Spot-spraying on the weeds only becomes economically feasible.

  9. Spatial and Spectral Methods for Weed Detection and Localization

    NASA Astrophysics Data System (ADS)

    Vioix, Jean-Baptiste; Douzals, Jean-Paul; Truchetet, Frédéric; Assémat, Louis; Guillemin, Jean-Philippe

    2002-12-01

    This study concerns the detection and localization of weed patches in order to improve the knowledge on weed-crop competition. A remote control aircraft provided with a camera allowed to obtain low cost and repetitive information. Different processings were involved to detect weed patches using spatial then spectral methods. First, a shift of colorimetric base allowed to separate the soil and plant pixels. Then, a specific algorithm including Gabor filter was applied to detect crop rows on the vegetation image. Weed patches were then deduced from the comparison of vegetation and crop images. Finally, the development of a multispectral acquisition device is introduced. First results for the discrimination of weeds and crops using the spectral properties are shown from laboratory tests. Application of neural networks were mostly studied.

  10. Applying a weed risk assessment approach to GM crops.

    PubMed

    Keese, Paul K; Robold, Andrea V; Myers, Ruth C; Weisman, Sarah; Smith, Joe

    2014-12-01

    Current approaches to environmental risk assessment of genetically modified (GM) plants are modelled on chemical risk assessment methods, which have a strong focus on toxicity. There are additional types of harms posed by plants that have been extensively studied by weed scientists and incorporated into weed risk assessment methods. Weed risk assessment uses robust, validated methods that are widely applied to regulatory decision-making about potentially problematic plants. They are designed to encompass a broad variety of plant forms and traits in different environments, and can provide reliable conclusions even with limited data. The knowledge and experience that underpin weed risk assessment can be harnessed for environmental risk assessment of GM plants. A case study illustrates the application of the Australian post-border weed risk assessment approach to a representative GM plant. This approach is a valuable tool to identify potential risks from GM plants. PMID:24046097

  11. Study of red-sore disease in alligators. Final report, September 1, 1976-September 3, 1980. [Predisposing factors

    SciTech Connect

    Gorden, R.E.; Esch, G.W.

    1980-01-01

    Necropsies of eight alligators which died following capture within a thermally-altered reservoir demonstrated the presence of the gram negative, pathogenic bacterium Aeromonas hydrophila, in internal tissues. A study designed to demonstrate whether A. hydrophila were capable of causing infection and death of the ecologically threatened alligator and, if so, the mechanism of exposure and infection in natural habitats was undertaken. The pathology and response to infection were also studied. When juvenile alligators were exposed under experimental conditions to increasing concentrations of A. hydrophila in water, by oral inoculation, or by intramuscular injections at 20/sup 0/, 25/sup 0/, 30/sup 0/, and 35/sup 0/C, they developed external lesions. These lesions were likely to become severe and lead to death of the animal at 30 and 35/sup 0/C. Infected animals produced: (a) increased numbers of white blood cells; (b) increased specific antibody titer; and (c) alpha 2 peaks higher than albumen peaks (except at 35/sup 0/C). Biweekly intraperitoneal injections of live, washed A. hydrophila were apparently more effective in the prevention of infection and of external lesions than were the antibiotics Kanamycin and OTH-Puramycin. Topical applications of Neosporin ointment resulted in the healing of severe lesions on confined animals. Alligators which were shown to be exposed to A. hydrophila in their natural habitats showed no external evidence of infection by the bacteria. It is recommended that exposure to conditions of stress, including water temperatures greater than 30/sup 0/C, be kept to a minimum during the capture, transport, and captivity of alligators. (ERB)

  12. RNAseq reveals weed-induced PIF3-like as a candidate target to manipulate weed stress response in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research conducted, including the rationale: Weeds reduce yield in soybeans through incompletely defined mechanisms. The effects of weeds on the soybean transcriptome were evaluated in field conditions during four separate growing seasons. Methods: RNASeq data were collected from 6 biological sam...

  13. Current substances for organic weed control in vegetables or what do we have in our organic weed control tool box?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is the top research priority among organic producers. Organic producers have a short, but growing list of organic approved herbicides. The purpose of this publication is to provide general overview of weed control options for organic crop production. Research has demonstrated that co...

  14. PUTTING PLANT PATHOGENS TO WORK: PROGRESS AND POSSIBILITIES IN WEED BIOCONTROL PART 2. IMPROVING WEED CONTROL EFFICACY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of plant pathogenic weed biological control agents can be approached using two strategies, termed the classical and biological approaches. The classical involves the search for pathogens in the native range of an invasive weed and its importation and release into the area of introdu...

  15. EFFECT OF ACUTE STRESS ON PLASMA CONCENTRATIONS OF SEX AND STRESS HORMONES IN JUVENILE ALLIGATORS LIVING IN CONTROL AND CONTAMINATED LAKES

    EPA Science Inventory

    Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligat...

  16. THE FUNCTIONAL AND STRUCTURAL OBSERVATIONS OF THE NEONATAL REPRODUCTIVE SYSTEM OF ALLIGATORS EXPOSED IN OVO TO ATRAZINE, 2,4-D, OR ESTRADIOL.

    EPA Science Inventory

    Wild alligators exposed to persistent organochlorine contaminants, municipal waste compounds, and contemporary-use herbicides exhibit reproductive alterations that are thought to be caused by endocrine disruption. This study tests the hypothesis that these alterations, at least i...

  17. Use of weeds as traditional vegetables in Shurugwi District, Zimbabwe

    PubMed Central

    2013-01-01

    Background Most agricultural weeds are usually regarded as undesirable and targeted for eradication. However, weeds are useful to human beings as food and traditional medicines. Few studies have been done to document the uses of weeds as traditional vegetables. This study was therefore, done to document indigenous knowledge related to the diversity and use of agricultural weeds as traditional vegetables in Shurugwi District, Zimbabwe, emphasizing their role in food security and livelihoods of the local people. Materials and methods Semi-structured interviews, observation and guided field walks with 147 participants were employed between December 2011 and January 2012 to obtain ethnobotanical data on the use of edible weeds as traditional vegetables. Based on ethnobotanical information provided by the participants, botanical specimens were collected, numbered, pressed and dried for identification. Results A total of 21 edible weeds belonging to 11 families and 15 genera, mostly from Amaranthaceae (19%), Asteraceae and Tiliaceae (14.3%), Capparaceae, Cucurbitaceae and Solanaceae (9.5% each) were identified. Of the documented edible weeds, 52.4% are indigenous while 47.6% are exotic to Zimbabwe; either semi-cultivated or growing naturally as agricultural weeds in farmlands, fallow land and home gardens. Among the main uses of edible weeds were leafy vegetables (81%), followed by edible fruits (19%), edible corms (9.5%), edible flowers and seeds (4.8% each). The most important edible weeds were Cleome gynandra, cited by 93.9% of the participants, Cucumis metuliferus (90.5%), Cucumis anguria (87.8%), Corchorus tridens (50.3%) and Amaranthus hybridus (39.5%). All edible weeds were available during rainy and harvest period with Cleome gynandra, Corchorus tridens, Cucumis anguria, Cucumis metuliferus and Moringa oleifera also available during the dry season, enabling households to obtain food outputs in different times of the year. The importance of edible weeds for local

  18. Managing Weeds in Potato Health Management, ed. D. Johnson. APS Press

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weeds must be managed throughout the entire crop rotation to optimize potato tuber yield and quality. Understanding factors that promote weed species and allow them to persist in crop rotations is key to designing cropping systems that discourage and reduce the impact of weeds. Weeds can be best man...

  19. Vinegar (20% acetic acid) broadcast application for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic weed control research was conducted in southeast Oklahoma to determine the effect of broadcast over-the-top applications of acetic acid (vinegar) on weed control efficacy, crop injury and onion yields. The experiment included 6 weed control treatments (2 application volumes, 2 hand-weeding ...

  20. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  1. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  2. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  3. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  4. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  5. 7 CFR 360.300 - Notice of restrictions on movement of noxious weeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Notice of restrictions on movement of noxious weeds... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.300 Notice of restrictions on movement of noxious weeds. No person may move a Federal noxious weed into...

  6. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  7. 7 CFR 360.305 - Disposal of noxious weeds when permits are canceled.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Disposal of noxious weeds when permits are canceled... AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE NOXIOUS WEED REGULATIONS § 360.305 Disposal of noxious weeds when permits are canceled. When a permit for the movement of a noxious weed...

  8. Lawn Weeds and Their Control. North Central Regional Extension Publication No. 26.

    ERIC Educational Resources Information Center

    Purdue Univ., Lafayette, IN. Cooperative Extension Service.

    This publication discusses lawn weed control for the twelve state north central region of the country. Written for use by homeowners, the publication focuses on weed identification and proper herbicide selection and application. Identification of weeds and safe and appropriate herbicide use are emphasized. Forty-six weed and turf plants are…

  9. Early corn growth and development in response to weed, nitrogen, and shade stresses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early season crop-weed interactions during a critical weed-free period (CWFP) influence corn growth that commonly results in reduced yield. Yield loss is not mitigated by weed removal after the CWFP, hence, weeds cause an irreversible negative impact on growth and development during the CWFP. Howeve...

  10. Economics of supplemental weed control applications on spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field research conducted to determine the relative benefits among alternative herbicides for weed control in onions (Allium cepa L.) measured weed control efficacy, impact of herbicides on crop injury, and the resulting weed competition on crop yields and marketable bulb size. Weed competition produ...

  11. Wallowa Canyonlands Weed Partnership : Completion Report November 19, 2009

    SciTech Connect

    Porter, Mark C.; Ketchum, Sarah

    2008-12-30

    Noxious weeds threaten fish and wildlife habitat by contributing to increased sedimentation rates, diminishing riparian structure and function, and reducing forage quality and quantity. Wallowa Resources Wallowa Canyonlands Partnership (WCP) protects the unique ecological and economic values of the Hells Canyon grasslands along lower Joseph Creek, the lower Grande Ronde and Imnaha Rivers from invasion and degradation by noxious weeds using Integrated Weed Management techniques. Objectives of this grant were to inventory and map high priority weeds, coordinate treatment of those weeds, release and monitor bio-control agents, educate the public as to the dangers of noxious weeds and how to deal with them, and restore lands to productive plant communities after treatment. With collaborative help from partners, WCP inventoried {approx} 215,000 upland acres and 52.2 miles of riparian habitat, released bio-controls at 23 sites, and educated the public through posters, weed profiles, newspaper articles, and radio advertisements. Additionally, WCP used other sources of funding to finance the treatment of 1,802 acres during the course of this grant.

  12. Capabilities of unmanned aircraft vehicles for low altitude weed detection

    NASA Astrophysics Data System (ADS)

    Pflanz, Michael; Nordmeyer, Henning

    2014-05-01

    Sustainable crop production and food security require a consumer and environmental safe plant protection. It is recently known, that precise weed monitoring approaches could help apply pesticides corresponding to field variability. In this regard the site-specific weed management may contribute to an application of herbicides with higher ecologically aware and economical savings. First attempts of precision agriculture date back to the 1980's. Since that time, remote sensing from satellites or manned aircrafts have been investigated and used in agricultural practice, but are currently inadequate for the separation of weeds in an early growth stage from cultivated plants. In contrast, low-cost image capturing at low altitude from unmanned aircraft vehicles (UAV) provides higher spatial resolution and almost real-time processing. Particularly, rotary-wing aircrafts are suitable for precise path or stationary flight. This minimises motion blur and provides better image overlapping for stitching and mapping procedures. Through improved image analyses and the recent increase in the availability of microcontrollers and powerful batteries for UAVs, it can be expected that the spatial mapping of weeds will be enhanced in the future. A six rotors microcopter was equipped with a modified RGB camera taking images from agricultural fields. The hexacopter operates within predefined pathways at adjusted altitudes (from 5 to 10 m) by using GPS navigation. Different scenarios of optical weed detection have been carried out regarding to variable altitude, image resolution, weed and crop growth stages. Our experiences showed high capabilities for site-specific weed control. Image analyses with regard to recognition of weed patches can be used to adapt herbicide application to varying weed occurrence across a field.

  13. Control of aquatic weeds through pollutant reduction and weed utilization: a weed management approach in the lower Kafue River of Zambia

    NASA Astrophysics Data System (ADS)

    Sinkala, Thomson; Mwase, Enala T.; Mwala, Mick

    The aquatic weed situation in the Kafue River in Zambia continues to be a major challenge to the sustainable utilization of the water resources of the river. The general methods for managing the weeds, especially the water hyacinth, include use of bio-agents, chemicals, mechanical and physical approaches. These have had very little impact. This paper reports on a project that is investigating weed management strategies which involve use of cleaner production (CP) approach and the utilization of the weed for economic purposes. In addition, the ecological implications of these methods are being assessed. Effluent assessments indicated that apart from nitrates and phosphates, other effluent parameters met the Environmental Council of Zambia standards. Results further show that all the 24 areas surveyed for CP have uncontrolled socio-economic activities which generate both point and non-point sources of pollution that enter the water bodies. To minimize pollution, efforts include devising policy and technical strategies with the involvement of the affected riparian community. Production of mushroom by the communities using the water hyacinth substrate has been demonstrated. Up to 2.1 kg of mushroom was harvested from a single flush over a period of 4-5 weeks. Vegetables grown on soils treated with water hyacinth manure performed better than those grown using commercial fertiliser. The economics of the production are however, yet to be confirmed. If weed usage is proven economically and ecologically viable, the riverine community is envisaged to play a big role in aquatic weed management. High numbers of invertebrates known to be sensitive to pollution have been recorded in the weed-infested Kafue River implying that the water is of “good” quality for these aquatic invertebrates. This observed quality of water may be due to water hyacinth playing a role by sieving pollutants from the river.

  14. Guidelines for choosing molecular "alligator clip" binding motifs in electron transport devices

    NASA Astrophysics Data System (ADS)

    Reuter, Matthew G.; Seideman, Tamar; Ratner, Mark A.

    2011-04-01

    We employ a one-electron, tight-binding model of an electrode-molecule-electrode junction to explore the fundamental relationship between adsorption geometry and electron transport, producing exact results (within this model). By varying the chemisorption location (e.g., atop a surface atom or in a hollow site between surface atoms) and the molecule-electrode coupling, we find that the largest currents are realized when the molecule (i) is highly coordinated by the surface and (ii) has favorable overlap with electrode states near the Fermi level. We also show the importance of electrode-induced molecular level shifting for certain adsorption geometries, which can cause molecular levels far from the Fermi level to conduct better than those near the Fermi level. Since all of these factors are greatly influenced by the chemical moiety used to link the molecule to an electrode, these results present a set of guidelines to help choose "alligator clips" for molecular electronic devices.

  15. Evolution of corticosteroid specificity for human, chicken, alligator and frog glucocorticoid receptors.

    PubMed

    Katsu, Yoshinao; Kohno, Satomi; Oka, Kaori; Baker, Michael E

    2016-09-01

    We investigated the evolution of the response of human, chicken, alligator and frog glucocorticoid receptors (GRs) to dexamethasone, cortisol, cortisone, corticosterone, 11-deoxycorticosterone, 11-deoxycortisol and aldosterone. We find significant differences among these vertebrates in the transcriptional activation of their full length GRs by these steroids, indicating that there were changes in the specificity of the GR for steroids during the evolution of terrestrial vertebrates. To begin to study the role of interactions between different domains on the GR in steroid sensitivity and specificity for terrestrial GRs, we investigated transcriptional activation of truncated GRs containing their hinge domain and ligand binding domain (LBD) fused to a GAL4 DNA binding domain (GAL4-DBD). Compared to corresponding full length GRs, transcriptional activation of GAL4-DBD_GR-hinge/LBD constructs required higher steroid concentrations and displayed altered steroid specificity, indicating that interactions between the hinge/LBD and other domains are important in glucocorticoid activation of these terrestrial GRs. PMID:27317937

  16. ALLIGATOR - An apparatus for ion beam assisted deposition with a broad-beam ion source

    NASA Astrophysics Data System (ADS)

    Wituschek, H.; Barth, M.; Ensinger, W.; Frech, G.; Rück, D. M.; Leible, K. D.; Wolf, G. K.

    1992-04-01

    Ion beam assisted deposition is a versatile technique for preparing thin films and coatings for various applications. Up to now a prototype setup for research purposes has been used in our laboratory. Processing of industrial standard workpieces requires a high current ion source with broad beam and high uniformity for homogeneous bombardment. In this contribution a new apparatus for large area samples will be described. It is named ALLIGATOR (German acronym of facility for ion assisted evaporation on transverse movable or rotary targets). In order to have a wide energy range available two ion sources are used. One delivers a beam energy up to 1.3 keV. The other is suitable for energies from 5 keV up to 40 keV. The ``high-energy'' ion source is a multicusp multiaperture source with 180-mA total current and a beam diameter of 280 mm at the target position.

  17. Ontogeny of the Middle-Ear Air-Sinus System in Alligator mississippiensis (Archosauria: Crocodylia)

    PubMed Central

    Dufeau, David L.; Witmer, Lawrence M.

    2015-01-01

    Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic sinuses invading the cranium. These sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph—indeed archosaurian—evolution is characterized by the evolution of various paratympanic air sinuses, the homologies of which are poorly understood due in large part to the fact that individual sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these sinuses primarily to clarify the anatomical relations of the individual sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic sinuses are simply an allometric function of braincase

  18. Functional specialization and ontogenetic scaling of limb anatomy in Alligator mississippiensis

    PubMed Central

    Allen, Vivian; Elsey, Ruth M; Jones, Nicola; Wright, Jordon; Hutchinson, John R

    2010-01-01

    Crocodylians exhibit a fascinating diversity of terrestrial gaits and limb motions that remain poorly described and are of great importance to understanding their natural history and evolution. Their musculoskeletal anatomy is pivotal to this diversity and yet only qualitative studies of muscle-tendon unit anatomy exist. The relative masses and internal architecture (fascicle lengths and physiological cross-sectional areas) of muscles of the pectoral and pelvic limbs of American alligators (Alligator mississippiensis Daudin 1801) were recorded for an ontogenetic series of wild specimens (n = 15, body masses from 0.5 to 60 kg). The data were analysed by reduced major axis regression to determine scaling relationships with body mass. Physiological cross-sectional areas and therefore muscle force-generating capacity were found to be greater in the extensor (anti-gravity) muscles of the pelvic limb than in the pectoral limb, reflecting how crocodylians differ from mammals in having greater loading of the hindlimbs than the forelimbs. Muscle masses and architecture were generally found to scale isometrically with body mass, suggesting an ontogenetic decrease in terrestrial athleticism. This concurs with the findings of previous studies showing ontogenetic decreases in limb bone length and the general scaling principle of a decline of strength : weight ratios with increasing size in animals. Exceptions to isometric scaling found included positive allometry in fascicle length for extensor musculature of both limbs, suggesting an ontogenetic increase in working range interpreted as increasing postural variability – in particular the major hip extensors – the interpretation of which is complicated by previous described ontogenetic increase of moment arms for these muscles. PMID:20148991

  19. Ontogeny of the Middle-Ear Air-Sinus System in Alligator mississippiensis (Archosauria: Crocodylia).

    PubMed

    Dufeau, David L; Witmer, Lawrence M

    2015-01-01

    Modern crocodylians, including Alligator mississippiensis, have a greatly elaborated system of pneumatic sinuses invading the cranium. These sinuses invade nearly all the bones of the chondrocranium and several bony elements of the splanchnocranium, but patterns of postnatal paratympanic sinus development are poorly understood and documented. Much of crocodylomorph--indeed archosaurian--evolution is characterized by the evolution of various paratympanic air sinuses, the homologies of which are poorly understood due in large part to the fact that individual sinuses tend to become confluent in adults, obscuring underlying patterns. This study seeks to explore the ontogeny of these sinuses primarily to clarify the anatomical relations of the individual sinuses before they become confluent and thus to provide the foundation for later studies testing hypotheses of homology across extant and extinct Archosauria. Ontogeny was assessed using computed tomography in a sample of 13 specimens covering an almost 19-fold increase in head size. The paratympanic sinus system comprises two major inflations of evaginated pharyngeal epithelium: the pharyngotympanic sinus, which communicates with the pharynx via the lateral (true) Eustachian tubes and forms the cavum tympanicum proprium, and the median pharyngeal sinus, which communicates with the pharynx via the median pharyngeal tube. Each of these primary inflations gives rise to a number of secondary inflations that further invade the bones of the skull. The primary sinuses and secondary diverticula are well developed in perinatal individuals of Alligator, but during ontogeny the number and relative volumes of the secondary diverticula are reduced. In addition to describing the morphological ontogeny of this sinus system, we provide some preliminary exploratory analyses of sinus function and allometry, rejecting the hypothesis that changes in the volume of the paratympanic sinuses are simply an allometric function of braincase

  20. Weed Control Sprayers: Calibration and Maintenance. Special Circular 81.

    ERIC Educational Resources Information Center

    Myers, Arthur L.

    This manual covers aspects of calibration and maintenance of weed control sprayers including variables affecting application rate, the pre-calibration check, calculations, band spraying, nozzle tip selection, agitation, and cleaning. (BB)

  1. Cultural control of weeds in herbicide-free annual forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The adoption of zero tillage systems improves soil water conservation, allowing for increased crop intensification and diversification in the semiarid northern Great Plains. Zero tillage systems rely primarily on herbicides for weed management, increasing selection pressure for herbicide resistance...

  2. DEVELOPING WEED SUPPRESSIVE SOILS THROUGH IMPROVED SOIL QUALITY MANAGEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable agriculture is based in part on efficient management of soil microorganisms for improving soil quality. However, identification of biological indicators of soil quality for predicting weed suppression in soils has received little attention. We investigated differences in soil microbial ...

  3. Mapping invasive weeds and their control with spatial information technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We discuss applications of airborne multispectral digital imaging systems, imaging processing techniques, global positioning systems (GPS), and geographic information systems (GIS) for mapping the invasive weeds giant salvinia (Salvinia molesta) and Brazilian pepper (Schinus terebinthifolius) and fo...

  4. The biology of habitat dominance; can microbes behave as weeds?

    PubMed

    Cray, Jonathan A; Bell, Andrew N W; Bhaganna, Prashanth; Mswaka, Allen Y; Timson, David J; Hallsworth, John E

    2013-09-01

    Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These 'microbial weeds' are able to dominate the communities that develop in fertile but uncolonized--or at least partially vacant--habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi. Some microbes

  5. Crop performance and weed suppression by weed-suppressive rice cultivars in furrow- and flood-irrigated systems under reduced herbicide inputs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control in rice is challenging, particularly in light of increased resistance to herbicides in weed populations and diminishing availability of irrigation water. Certain indica rice cultivars can produce high yields and suppress weeds in conventional flood-irrigated, drill-seeded systems in the...

  6. Herbicide-resistant crops and weed resistance to herbicides.

    PubMed

    Owen, Micheal D K; Zelaya, Ian A

    2005-03-01

    The adoption of genetically modified (GM) crops has increased dramatically during the last 3 years, and currently over 52 million hectares of GM crops are planted world-wide. Approximately 41 million hectares of GM crops planted are herbicide-resistant crops, which includes an estimated 33.3 million hectares of herbicide-resistant soybean. Herbicide-resistant maize, canola, cotton and soybean accounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat, and as many as 14 other crops have transgenic herbicide-resistant cultivars that may be commercially available in the near future. There are many risks associated with the production of GM and herbicide-resistant crops, including problems with grain contamination, segregation and introgression of herbicide-resistant traits, marketplace acceptance and an increased reliance on herbicides for weed control. The latter issue is represented in the occurrence of weed population shifts, the evolution of herbicide-resistant weed populations and herbicide-resistant crops becoming volunteer weeds. Another issue is the ecological impact that simple weed management programs based on herbicide-resistant crops have on weed communities. Asiatic dayflower (Commelina cumminus L) common lambsquarters (Chenopodium album L) and wild buckwheat (Polygonum convolvulus L) are reported to be increasing in prominence in some agroecosystems due to the simple and significant selection pressure brought to bear by herbicide-resistant crops and the concomitant use of the herbicide. Finally, evolution of herbicide-resistant weed populations attributable to the herbicide-resistant crop/herbicide program has been observed. Examples of herbicide-resistant weeds include populations of horseweed (Conyza canadensis (L) Cronq) resistant to N-(phosphonomethyl)glycine (glyphosate). An important question is whether or not these problems represent significant economic issues for future agriculture. PMID:15668920

  7. Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination

    PubMed Central

    Jeon, Hong Y.; Tian, Lei F.; Zhu, Heping

    2011-01-01

    An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA). PMID:22163954

  8. Effect of tillage system on yield and weed populations of soybean ( Glycin Max L.).

    PubMed

    Hosseini, Seyed Z; Firouzi, Saeed; Aminpanah, Hashem; Sadeghnejhad, Hamid R

    2016-03-01

    Field experiment was conducted at Agricultural and Natural Resources Research Center of Golestan Province, Iran, to determine the effects of tillage system and weed management regime on yield and weed populations in soybean ( Glycin max L.). The experimental design was a split plot where the whole plot portion was a randomized complete block with three replicates. Main plots were tillage system: 1- No-till row crop seeding, 2- No-till seed drilling, 3- Tillage with disc harrow and drill planting, 4- Tillage with chisel packer and drill planting. The subplots were weed management regimes: 1-Weed control with herbicide application, 2- Hand weeding, 3- Herbicide application plus hand weeding, and 4- Non-weeding. Results indicated that the main effects of tillage system and weed management regime were significant for seed yield, pod number per plant, seed number per pod, weed density and biomass, while their interaction were significant only for weed density, weed biomass, and seed number per pod. The highest grain yields (3838 kg ha-1) were recorded for No-till row crop seeding. The highest seed yield (3877 kg ha-1) also was recorded for weed control with herbicide and hand weeding treatment, followed by hand weeding (3379 kg ha-1). PMID:26871488

  9. Nuclear β-catenin localization supports homology of feathers, avian scutate scales, and alligator scales in early development.

    PubMed

    Musser, Jacob M; Wagner, Günter P; Prum, Richard O

    2015-01-01

    Feathers are an evolutionary novelty found in all extant birds. Despite recent progress investigating feather development and a revolution in dinosaur paleontology, the relationship of feathers to other amniote skin appendages, particularly reptile scales, remains unclear. Disagreement arises primarily from the observation that feathers and avian scutate scales exhibit an anatomical placode-defined as an epidermal thickening-in early development, whereas alligator and other avian scales do not. To investigate the homology of feathers and archosaur scales we examined patterns of nuclear β-catenin localization during early development of feathers and different bird and alligator scales. In birds, nuclear β-catenin is first localized to the feather placode, and then exhibits a dynamic pattern of localization in both epidermis and dermis of the feather bud. We found that asymmetric avian scutate scales and alligator scales share similar patterns of nuclear β-catenin localization with feathers. This supports the hypothesis that feathers, scutate scales, and alligator scales are homologous during early developmental stages, and are derived from early developmental stages of an asymmetric scale present in the archosaur ancestor. Furthermore, given that the earliest stage of β-catenin localization in feathers and archosaur scales is also found in placodes of several mammalian skin appendages, including hair and mammary glands, we hypothesize that a common skin appendage placode originated in the common ancestor of all amniotes. We suggest a skin placode should not be defined by anatomical features, but as a local, organized molecular signaling center from which an epidermal appendage develops. PMID:25963196

  10. Necropsy findings in American alligator late-stage embryos and hatchlings from northcentral Florida lakes contaminated with organochlorine pesticides

    USGS Publications Warehouse

    Sepulveda, M.S.; Del, Piero F.; Wiebe, J.J.; Rauschenberger, H.R.; Gross, T.S.

    2006-01-01

    Increased American alligator (Alligator mississippiensis) embryo and neonatal mortality has been reported from several northcentral Florida lakes contaminated with old-use organochlorine pesticides (OCPs). However, a clear relationship among these contaminants and egg viability has not been established, suggesting the involvement of additional factors in these mortalities. Thus, the main objective of this study was to determine the ultimate cause of mortality of American alligator late-stage embryos and hatchlings through the conduction of detailed pathological examinations, and to evaluate better the role of OCPs in these mortalities. Between 2000 and 2001, 236 dead alligators were necropsied at or near hatching (after ???65 days of artificial incubation and up to 1 mo of age posthatch). Dead animals were collected from 18 clutches ranging in viability from 0% to 95%. Total OCP concentrations in yolk ranged from ???100 to 52,000 ??g/kg, wet weight. The most common gross findings were generalized edema (34%) and organ hyperemia (29%), followed by severe emaciation (14%) and gross deformities (3%). Histopathologic examination revealed lesions in 35% of the animals, with over half of the cases being pneumonia, pulmonary edema, and atelectasis. Within and across clutches, dead embryos and hatchlings compared with their live cohorts were significantly smaller and lighter. Although alterations in growth and development were not related to yolk OCPs, there was an increase in prevalence of histologic lesions in clutches with high OCPs. Overall, these results indicate that general growth retardation and respiratory abnormalities were a major contributing factor in observed mortalities and that contaminants may increase the susceptibility of animals to developing certain pathologic conditions. ?? Wildlife Disease Association 2006.

  11. Predicting maternal body burdens of organochlorine pesticides from eggs and evidence of maternal transfer in Alligator mississippiensis

    USGS Publications Warehouse

    Rauschenberger, R.H.; Sepulveda, M.S.; Wiebe, J.J.; Szabo, N.J.; Gross, T.S.

    2004-01-01

    Few data exist regarding maternal-embryonal transfer of organochlorine pesticides (OCPs) in reptiles. The objective of the present study was to evaluate maternal transfer of OCPs in American alligators (Alligator mississippiensis) from low-, intermediate-, and high-OCP-exposure sites. Overall, total OCP burdens ranged from less than 0.8 ppb in blood to more than 44,000 ppb in abdominal adipose tissue (wet wt concentrations). Lipid-adjusted ratios of maternal adipose burdens (total OCPs) to yolk burdens were close to one (0.94 ?? 0.31:1), suggesting that animals were in steady state and that OCPs in eggs originated from adipose lipids. In contrast, lipid-adjusted muscle and liver OCP burdens were greater than yolk OCP burdens, suggesting that lipids in muscle were not utilized during oogenesis and that nonlipid liver tissue sequesters OCPs. Predictive equations were derived for several tissues and several OCP analytes with r2 values ranging from 0.40 to 0.99 (p < 0.05). We suggest that yolk burdens are predictive of maternal tissue burdens for certain tissues and OCPs and that certain OCPs are maternally transferred in the American alligator. Furthermore, we suggest that future studies should investigate the applicability of these predictive equations for assessing maternal exposure in other crocodilian species.

  12. Interspecific variation in persistence of buried weed seeds follows trade-offs among physiological, chemical and physical seed defences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil seedbanks drive infestations of annual weeds, yet weed management focuses largely on seedling mortality. As weed seedbanks increasingly become reservoirs of herbicide resistance, species-specific seedbank management approaches will be essential. Limited understanding of interspecific variation ...

  13. The biology of habitat dominance; can microbes behave as weeds?

    PubMed Central

    Cray, Jonathan A; Bell, Andrew N W; Bhaganna, Prashanth; Mswaka, Allen Y; Timson, David J; Hallsworth, John E

    2013-01-01

    Summary Competition between microbial species is a product of, yet can lead to a reduction in, the microbial diversity of specific habitats. Microbial habitats can resemble ecological battlefields where microbial cells struggle to dominate and/or annihilate each other and we explore the hypothesis that (like plant weeds) some microbes are genetically hard-wired to behave in a vigorous and ecologically aggressive manner. These ‘microbial weeds’ are able to dominate the communities that develop in fertile but uncolonized – or at least partially vacant – habitats via traits enabling them to out-grow competitors; robust tolerances to habitat-relevant stress parameters and highly efficient energy-generation systems; avoidance of or resistance to viral infection, predation and grazers; potent antimicrobial systems; and exceptional abilities to sequester and store resources. In addition, those associated with nutritionally complex habitats are extraordinarily versatile in their utilization of diverse substrates. Weed species typically deploy multiple types of antimicrobial including toxins; volatile organic compounds that act as either hydrophobic or highly chaotropic stressors; biosurfactants; organic acids; and moderately chaotropic solutes that are produced in bulk quantities (e.g. acetone, ethanol). Whereas ability to dominate communities is habitat-specific we suggest that some microbial species are archetypal weeds including generalists such as: Pichia anomala, Acinetobacter spp. and Pseudomonas putida; specialists such as Dunaliella salina, Saccharomyces cerevisiae, Lactobacillus spp. and other lactic acid bacteria; freshwater autotrophs Gonyostomum semen and Microcystis aeruginosa; obligate anaerobes such as Clostridium acetobutylicum; facultative pathogens such as Rhodotorula mucilaginosa, Pantoea ananatis and Pseudomonas aeruginosa; and other extremotolerant and extremophilic microbes such as Aspergillus spp., Salinibacter ruber and Haloquadratum walsbyi

  14. Tillage and residue burning affects weed populations and seed banks.

    PubMed

    Narwal, S; Sindel, B M; Jessop, R S

    2006-01-01

    An integrated weed management approach requires alternative management practices to herbicide use such as tillage, crop rotations and cultural controls to reduce soil weed seed banks. The objective of this study was to examine the value of different tillage practices and stubble burning to exhaust the seed bank of common weeds from the northern grain region of Australia. Five tillage and burning treatments were incorporated in a field experiment, at Armidale (30 degrees 30'S, 151 degrees 40'E), New South Wales, Australia in July 2004 in a randomized block design replicated four times. The trial was continued and treatments repeated in July 2005 with all the mature plants from the first year being allowed to shed seed in their respective treatment plots. The treatments were (i) no tillage (NT), (ii) chisel ploughing (CP), (iii) mould board ploughing (MBP), (iv) wheat straw burning with no tillage (SBNT) and (v) wheat straw burning with chisel ploughing (SBC). Soil samples were collected before applying treatments and before the weeds flowered to establish the seed bank status of the various weeds in the soil. Wheat was sown after the tillage treatments. Burning treatments were only initiated in the second year, one month prior to tillage treatments. The major weeds present in the seed bank before initiating the trial were Polygonum aviculare, Sonchus oleraceus and Avena fatua. Tillage promoted the germination of other weeds like Hibiscus trionum, Medicago sativa, Vicia sp. and Phalaris paradoxa later in the season in 2004 and Convolvulus erubescens emerged as a new weed in 2005. The MBP treatment in 2004 reduced the weed biomass to a significantly lower level of 55 g/m2 than the other treatments of CP (118 g/m2) and NT plots (196 g/m2) (P < 0.05). However, in 2005 SBC and MBP treatments were similar in reducing the weed biomass. In 2004, the grain yield trend of wheat was significantly different between CP and NT, and MBP and NT (P < 0.05) with maximum yield of 5898

  15. Interaction of environmental chemicals with the estrogen and progesterone receptors from the oviduct of the American alligator.

    PubMed Central

    Vonier, P M; Crain, D A; McLachlan, J A; Guillette, L J; Arnold, S F

    1996-01-01

    Reports of reproductive abnormalities in the American alligator from Lake Apopka, Florida, have been linked to a spill of DDT and other pesticides suspected of having hormonelike activity. To determine whether environmental chemicals had the potential to function as exogenous hormones in the American alligator, we examined the ability of chemicals to bind the estrogen receptor (aER) and progesterone receptor (aPR) in a protein extract prepared from the oviduct of the alligator. In competition binding assays with [3H]17 beta-estradiol, some DDT metabolites showed inhibition of [3H]17 beta-estradiol binding to aER. A combination of DDTs demonstrated an additive decrease in [3H]17 beta-estradiol binding to aER. Modern-use chemicals such as alachlor, trans-nonachlor, endosulfan, and atrazine also competed with [3H]17 beta-estradiol for binding to the aER. To test the effect of chemicals identified in alligator eggs from Lake Apopka on [3H]17 beta-estradiol binding, we mixed these chemicals at concentrations measured in eggs in the competition binding assay. 2,2-bis(4-chlorophenyl)-N-(methoxymethyl)acetamide (p,p'-DDD) and trans-nonachlor, both found in Lake Apopka, interacted with aER, whereas others such as chlordane and toxaphene did not. Surprisingly, combinations of these chemicals decreased [3H]17 beta-estradiol binding in a greater than additive manner. To assess the ability of chemicals to interact with aPR, we performed commpetition binding assays with the synthetic progestin [3H]R5020. Most of the chemicals tested did not reduce [3H]R5020 binding to aPR, whereas endosulfan, alachlor, and kepone inhibited binding. These results provide the first evidence that environmental chemicals bind the aER and aPR from the American alligator, supporting the hypothesis that the reported reproductive abnormalities may be related to the modulation of endocrine-related responses. The findings that combinations of chemicals demonstrated a greater than additive interaction with

  16. Microfungal "weeds" in the leafcutter ant symbiosis.

    PubMed

    Rodrigues, A; Bacci, M; Mueller, U G; Ortiz, A; Pagnocca, F C

    2008-11-01

    Leafcutter ants (Formicidae: tribe Attini) are well-known insects that cultivate basidiomycete fungi (Agaricales: Lepiotaceae) as their principal food. Fungus gardens are monocultures of a single cultivar strain, but they also harbor a diverse assemblage of additional microbes with largely unknown roles in the symbiosis. Cultivar-attacking microfungi in the genus Escovopsis are specialized parasites found only in association with attine gardens. Evolutionary theory predicts that the low genetic diversity in monocultures should render ant gardens susceptible to a wide range of diseases, and additional parasites with roles similar to that of Escovopsis are expected to exist. We profiled the diversity of cultivable microfungi found in 37 nests from ten Acromyrmex species from Southern Brazil and compared this diversity to published surveys. Our study revealed a total of 85 microfungal strains. Fusarium oxysporum and Escovopsis were the predominant species in the surveyed gardens, infecting 40.5% and 27% of the nests, respectively. No specific relationship existed regarding microfungal species and ant-host species, ant substrate preference (dicot versus grass) or nesting habit. Molecular data indicated high genetic diversity among Escovopsis isolates. In contrast to the garden parasite, F. oxysporum strains are not specific parasites of the cultivated fungus because strains isolated from attine gardens have similar counterparts found in the environment. Overall, the survey indicates that saprophytic microfungi are prevalent in South American leafcutter ants. We discuss the antagonistic potential of these microorganisms as "weeds" in the ant-fungus symbiosis. PMID:18369523

  17. PERENNIAL CROP NURSERIES TREATED WITH METHYL BROMIDE AND ALTERNATIVE FUMIGANTS: EFFECTS ON WEED SEED VIABILITY, WEED DENSITIES, AND TIME REQUIRED FOR HAND WEEDING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control provided by alternative fumigants to methyl bromide (MeBr) needs to be tested in perennial crop nurseries in California because MeBr is being phased out in accordance with the Montreal Protocol, few herbicides are registered for perennial nursery use, and costs of other control measures...

  18. Utility of remote sensing for soybean and weed species differentiation

    NASA Astrophysics Data System (ADS)

    Gray, Cody Jack

    Weeds are typically found in aggregated patches within a production area. Remote sensing technologies have been incorporated into agricultural production systems to locate and manage these troublesome areas site-specifically. Correct weed identification is a key component when making proper weed control decisions. Research was implemented to evaluate the use of hyperspectral and multispectral reflectance data for proper weed and crop discrimination. The primary objectives of this research were to evaluate the utility of hyperspectral radiometry and multispectral imagery to differentiate soybean and six weed species commonly found in Mississippi. Additional objectives included evaluating the spectral characteristics of Palmer amaranth and pitted morningglory accessions collected across central and southern United States. Principal component analysis was ineffective in discriminating between species. Best spectral band combination analysis (BSBC) produced the greatest weed classification accuracies when comparing all classification techniques. The BSBC suggested three areas of interest for species discrimination in the short wavelength infrared portion of the electromagnetic spectrum. These areas of interest were located from 1445 to 1475 nm, 2030 to 2090 nm, and 2115 to 2135 nm. Classification accuracies increased for all species when these band regions were added than when using vegetation indices alone, suggesting greater crop and weed species differentiation can be obtained when using sensors that include these regions of the short wavelength infrared portion of the electromagnetic spectrum. Three supervised classification systems were implemented in multispectral imagery classification. The best classification accuracies of 90% or greater were obtained for many of the plant species at 10 and 12 weeks after emergence using either a 2-class or 3-class system. Palmleaf morningglory and pitted morningglory at the highest densities of 6 plants/m2 produced the highest

  19. The orientation and navigation of juvenile alligators: evidence of magnetic sensitivity

    USGS Publications Warehouse

    Rodda, Gordon H.

    1984-01-01

    Displaced juvenile alligators, Alligator mississipiensis, were released on land in a 9 m diameter dodecagonal arena to test their ability to orient in the absence of terrestrial landmarks. Navigational ability seemed to improve with age. When displaced along a fairly direct route yearlings (age 7–14 months) compensated for their displacement, moving in the direction from the arena to their home sites. When displaced by a circuitous route, yearlings failed to compensate for their displacement, exhibiting instead simple compass orientation in a direction that would have returned them to water had they been released on land near the site where they were captured. The older juveniles were oriented in a homeward direction under all displacement and test conditions. The latter animals may have been using geomagnetic map information to select their homeward directions as the errors in their homeward bearings correlated with small deviations in the geomagnetic field's dip angle at the time of the test (1980r s=−0.6047,P=0.0131, all testsr s= −0.4652,P=0.0084). This effect appeared to depend on a very short-term assessment of geomagnetic conditions, as values measured 20 min before or 30 min after the tests began did not correlate with the directions the animals moved. The older juveniles appeared to use magnetically quiet hours on the night of their capture as the baseline from which to measure the geomagnetic deviations that occurred at the time of the arena test. The magnitude of the magnetic effect in the older animals suggests that the geomagnetic information may have been used to perform a ‘map’ step, as small fluctuations in dip angle correlated with much larger deviations in homeward bearings. In addition, the compass-oriented yearlings and the seemingly route-based behavior of the homeward-oriented yearlings did not appear to be influenced by geomagnetic conditions. These findings have many parallels in results obtained from bird orientation studies

  20. Primary alkaline magmas associated with the Quaternary Alligator Lake volcanic complex, Yukon Territory, Canada

    NASA Astrophysics Data System (ADS)

    Eiché, G. E.; Francis, D. M.; Ludden, J. N.

    1987-02-01

    The Alligator Lake complex is a Quaternary alkaline volcanic center located in the southern Yukon Territory of Canada. It comprises two cinder cones which cap a shield consisting of five distinct lava units of basaltic composition. Units 2 and 3 of this shield are primitive olivine-phyric lavas (13.5 19.5 cation % Mg) which host abundant spinel lherzolite xenoliths, megacrysts, and granitoid fragments. Although the two lava types have erupted coevally from adjacent vents and are petrographically similar, they are chemically distinct. Unit 2 lavas have considerably higher abundances of LREE, LILE, and Fe, but lower HREE, Y, Ca, Si, and Al relative to unit 3 lavas. The 87Sr/86Sr and 143Nd/144Nd isotopic ratios of these two units are, however, indistinguishable. The differences between these two lava types cannot be explained in terms of low pressure olivine fractionation, and the low concentrations of Sr, Nb, P, and Ti in the granitoid xenoliths relative to the primitive lavas discounts differential crustal contamination. The abundance of spinel lherzolite xenoliths and the high Mg contents in the lavas of both units indicates that their compositional differences originated in the upper mantle. The Al and Si systematics of these lavas suggests that, compared to unit 3 magmas, the unit 2 magmas may have segregated at greater depths from a garnet lherzolite mantle. The identical isotopic composition and similar ratios of highly incompatible elements in these two lava units argues against their differences being a consequence of random metasomatism or mantle heterogeneity. The lower Y and HREE contents but higher concentrations of incompatible elements in the unit 2 lavas relative to unit 3 can be most simply explained by differential partial melting of similar garnet-bearing sources. The unit 2 magmas thus appear to have been generated by smaller degrees of melting at a greater depth than the unit 3 magmas. The contemporaneous eruption of two distinct but