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Search Results: 1 - 10 of 20977 matches for " Charles Linn Jr. "
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Silent genes and rare males: A fresh look at pheromone blend response specificity in the European corn borer moth, Ostrinia nubilalis
Charles Linn Jr.,Marion O'Connor,Wendell Roelofs
Journal of Insect Science , 2003,
Abstract: The response of male moths from two pheromone races of the European corn borer, Ostrinia nubilalis, was measured in a flight tunnel assay to different ratios of structurally different compounds that comprise the sex pheromone of the Asian corn borer, Ostrinia furnacalis. For both O. nubilalis races, between 1 and 5% of the males completed upwind flights to two different blends of the O. furnacalis pheromone components (the 2:1 Z/E12-14:OAc female-produced blend, and a 97:3 Z/E mix), confirming that rare males exist in the O. nubilalis populations that can detect and respond to mixtures of the O. furnacalis pheromone components. Rare males that responded to the O. furnacalis blends also responded to their own O. nubilalis blends (97:3 or 1:99 Z/E11-14:OAc), indicating that rare O. nubilalis males are not preferentially sensitive to mixtures of the O. furnacalis compounds, but rather that they have a broad range of response specificity, which includes recognition of a wide range of conspecific female-produced ratios, and also recognition of heterospecific mixtures. The results support the hypothesis that saltational shifts in pheromone blend composition (Roelofs et al., 2002) can lead to the evolution of a new species-specific communication system, in part because the broad response specificity of some males includes the ability to respond in an agonistic manner to novel mixtures of compounds.
Eavesdropping on Plant Volatiles by a Specialist Moth: Significance of Ratio and Concentration
Dong H. Cha,Charles E. Linn Jr.,Peter E. A. Teal,Aijun Zhang,Wendell L. Roelofs,Gregory M. Loeb
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017033
Abstract: We investigated the role that the ratio and concentration of ubiquitous plant volatiles play in providing host specificity for the diet specialist grape berry moth Paralobesia viteana (Clemens) in the process of locating its primary host plant Vitis sp. In the first flight tunnel experiment, using a previously identified attractive blend with seven common but essential components (“optimized blend”), we found that doubling the amount of six compounds singly [(E)- & (Z)-linalool oxides, nonanal, decanal, β-caryophyllene, or germacrene-D], while keeping the concentration of other compounds constant, significantly reduced female attraction (average 76% full and 59% partial upwind flight reduction) to the synthetic blends. However, doubling (E)-4,8-dimethyl 1,3,7-nonatriene had no effect on female response. In the second experiment, we manipulated the volatile profile more naturally by exposing clonal grapevines to Japanese beetle feeding. In the flight tunnel, foliar damage significantly reduced female landing on grape shoots by 72% and full upwind flight by 24%. The reduction was associated with two changes: (1) more than a two-fold increase in total amount of the seven essential volatile compounds, and (2) changes in their relative ratios. Compared to the optimized blend, synthetic blends mimicking the volatile ratio emitted by damaged grapevines resulted in an average of 87% and 32% reduction in full and partial upwind orientation, respectively, and the level of reduction was similar at both high and low doses. Taken together, these results demonstrate that the specificity of a ubiquitous volatile blend is determined, in part, by the ratio of key volatile compounds for this diet specialist. However, P. viteana was also able to accommodate significant variation in the ratio of some compounds as well as the concentration of the overall mixture. Such plasticity may be critical for phytophagous insects to successfully eavesdrop on variable host plant volatile signals.
Sex Pheromone Receptor Specificity in the European Corn Borer Moth, Ostrinia nubilalis
Kevin W. Wanner,Andrew S. Nichols,Jean E. Allen,Peggy L. Bunger,Stephen F. Garczynski,Charles E. Linn Jr.,Hugh M. Robertson,Charles W. Luetje
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008685
Abstract: The European corn borer (ECB), Ostrinia nubilalis (Hubner), exists as two separate sex pheromone races. ECB(Z) females produce a 97:3 blend of Z11- and E11-tetradecenyl acetate whereas ECB(E) females produce an opposite 1:99 ratio of the Z and E isomers. Males of each race respond specifically to their conspecific female's blend. A closely related species, the Asian corn borer (ACB), O. furnacalis, uses a 3:2 blend of Z12- and E12-tetradecenyl acetate, and is believed to have evolved from an ECB-like ancestor. To further knowledge of the molecular mechanisms of pheromone detection and its evolution among closely related species we identified and characterized sex pheromone receptors from ECB(Z).
Small Mammal Habitat Use within Restored Riparian Habitats Adjacent to Channelized Streams in Mississippi  [PDF]
Peter C. Smiley Jr., Charles M. Cooper
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.411149
Abstract:

Riparian zones of channelized agricultural streams in northwestern Mississippi typically consist of narrow vegetative corridors low in habitat diversity and lacking riparian wetlands. Land clearing practices and stream channelization have led to the development of gully erosion and further fragmentation of these degraded riparian zones. Currently, installation of a gully erosion control structure (drop pipe) at the riparian zone-agricultural field interface leads to the incidental establishment of four riparian habitat types that differ in habitat area, vegetative structure, and pool size. Small mammals were sampled within four sites of each habitat type from June 1994 to July 1995. Small mammal diversity, abundance, and hispid cotton rat (Sigmodon hispidus) weight were the least within smallest Type I habitats with the least vegetative structural diversity and were the greatest within the larger Type II, III, or IV habitats having greater vegetative structural diversity and pool size. Small mammal diversity and abundance were the least in the summer 1994, increased in the fall 1994, and then declined later in our study. Hispid cotton rat abundance was the least in summer 1994, winter 1994, and spring 1995 and was the greatest in fall 1994 and summer 1995. Our results suggest that modifying the drop pipe installation design to facilitate the development of larger riparian habitats with greater vegetative structural diversity will provide the greatest benefits for small mammals.

Van der Vyver’s analysis of rights: a case study drawn from thirteenth-century canon law
Charles J. Reid, Jr.
Koers : Bulletin for Christian Scholarship , 1999, DOI: 10.4102/koers.v64i2&3.502
Abstract: In an important article published in 1988, Johan Van der Vyver challenged the prevailing reliance on Wesley Hohfeld’s taxonomy of rights. Hohfeld's division of rights into claims, powers, privileges and immunities, Van der Vyver stresses, is excessively concerned with "inter-individual legal relations” at the expense of the right-holder's relationship to the object of the right. Van der Vyver proposes instead that an assertion of right involves three distinct juridic aspects: legal capacity, which is "the competence to occupy the offices of legal subject; legal claim, which "comprises claims of a legal subject as against other persons to a legal object"; legal entitlement, which specifies the boundaries of the right-holder's ability to use, enjoy, consume, destroy or alienate the right in question. This article applies Van der Vyver’s taxonomy to the operations of thirteenthcentury canon law, and demonstrates that Van der Vyver’s analysis provides greater depth than Hohfeld's, in that it considers both the relationship of the person claiming a particular right and the object of that right.
LA PROMESA DE UNA ARQUEOLOGíA DEL MUNDO MODERNO EN AMéRICA DEL SUR, CON ESPECIAL REFERENCIA A ARGENTINA
Charles Orser Jr
Revista de Arqueología Histórica Argentina y Latinoamericana , 2007,
Abstract:
Automorphism Classes of Elements in Finitely Generated Abelian Groups
Charles F. Rocca Jr
Mathematics , 2011,
Abstract: We will show that every element of a finitely generated abelian group is automorphically equivalent what we will define to be a {\em representative element} in a {\em repeat-free subgroup}, and for finite abelian groups we can count the number of automorphism classes of elements.
Liver cytochrome P450 system as affected by endophyte-infected tall fescue seed extracts and ergot alkaloids  [PDF]
Ali S. Moubarak, Zelpha B. Johnson, Charles F. Rosenkrans Jr.
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.31001
Abstract: Endophyte infected tall fescue (E+) is the base diet for nearly all beef cattle in the southern USA. It has been linked to a variety of toxicological conditions due to the presence of large numbers of ergot alkaloids. This study was designed to investigate the effects of E+ seed extract and selected ergot alkaloids on the detoxification pathway by cytochrome P450 (CYP3A4) enzyme system. Tests were performed using the P450- Glo CYP3A4 enzyme activity kit (Promega, WI), according to the manufacturer’s manual. Luminescence was measured using a single tube TD20/20 luminometer. Endophyte infected tall fescue seed was extracted with 50/50 methanol/25 mM ammonium carbonate, cleaned and concentrated on Strata-X reversed phase column (Phenomenex). The extracts were evaluated on an HPLC, and then tested using a serial dilution method. Commercially available ergonovine (EN), ergocorine (ER), bromocryptine (BC) and ergocryptine (EC) were tested individually using 0 to 44 nM concentrations. Seed extract of E+ produced a significant (P < 0.05) dose dependent inhibition of CYP3A4 enzyme activity similar to that produced by the commercially available ergot alkaloids EC, ER, BC and EN which inhibited CYP3A4 enzyme activity in a significant (P < 0.05) dose dependent manner with EC being most potent, followed by ER, BC, and then EN (70%, 40%, 30% and 10% at 44 nM concentration). The similarity of the inhibition curves of seed extract to that of the commercially available ergot alkaloids suggests a related mode of action and that the use of such ergot alkaloids and CYP3A4 assay is a good model to study the toxicity of tall fescue. Furthermore, it provides the foundation to identify the individual toxic components of purified endophyte infected tall fescue extract.
CHK21100delC, I157T, IVS2 +IG > A, BRCA1 and BRCA2 Mutation Analysis in JF305: A Pancreatic Cancer Cell Line  [PDF]
Charles Ndawula Jr., Xueli Yang, Xiaohai Gong, Jian Jin
Journal of Biosciences and Medicines (JBM) , 2014, DOI: 10.4236/jbm.2014.21007
Abstract: JF305 is a highly prolific pancreatic cancer cell line that originated from a Chinese patient. The cell line bears a functional HR double strand DNA repair mechanism but very responsive to PARP treatment a phenomenon clearly suggesting presence of an anomaly in the mechanism. Brca1, Brca2 and CHK2 proteins are very important constituents of the HR mechanism whose respective gene coding mutations are strongly associated with several cancers and are widely exploited in anticancer chemotherapy. In this current study, the BRCA1, BRCA2 gene mutation status in JF305 was determined together with the presence of 3 widely reported cancer linked CHK2 founder mutations (1100delC, I157T, IVS2 +IG > A). CHK21100delC genotype was determined using allele specific PCR, while the PCR-RFLP assay was used for I157T, IVS2 +IG > A analysis. PCR and direct sequencing were used for assessing the BRCA1 and BRCA2 gene. Results revealed that JF305 is CHK21100delC heterozygous mutant, CHK2I157T and CHK2IVS2 +IG > A wild type. Furthermore, it was observed that JF305 lacked BRCA1 and BRCA2 gene mutations. The mutation status identification of CHK2 and BRCA1/2 in JF305 provides a major milestone towards elucidating the properties of the cell line which subsequently promises to be an excellent model for evaluating the role of parp inhibitors in pancreatic cancer chemotherapy most especially in the respective cancer cell lines without BRCA1 and BRCA2 gene mutations.
Ergot Alkaloid Effects on Bovine Sperm Motility In Vitro  [PDF]
Ryan Page, Toby Lester, Rick Rorie, Charles Rosenkrans Jr.
Advances in Reproductive Sciences (ARSci) , 2019, DOI: 10.4236/arsci.2019.71002
Abstract: Cattle in some parts of the world graze pastures that consist of tall fescue that may contain ergot alkaloid contamination. Those ergot alkaloids are associated with reduced reproductive rates in cattle. Our objective was to determine if ergot alkaloids [dihydroergotamine (DHET), ergonovine (EN), and ergotamine (ET)] directly affect bovine sperm characteristics. Spermatozoa were collected from mature Angus (n = 2) and Balancer (n = 4) bulls. Within bull, treatments were structured as a 3 × 5 factorial with three alkaloids (DHET, EN, and ET) and five concentrations of each alkaloid (0, 33, 66, 100, or 200 μM). Spermatozoa (25 × 106) were incubated (39?C) in 1 mL of modified sperm medium. Sperm motility characteristics were evaluated using CASA (Hamiliton Thorne IVOS, Beverly, MA) at 0, 3, and 6 h after initial alkaloid exposure. Initial sperm motility was (69% ± 1.1%) and declined (P = 0.01) to (35% ± 2.6%) at 6 h. Sperm motility decreased (P < 0.05) with increasing concentrations of DHET and ET, but not EN. As concentration of ET or DHET increased all CASA sperm characteristics were altered. The interaction of alkaloid concentration and incubation length affected sperm velocity and head size; exposure to 200 μM of ET or DHET for six hours decreased (P < 0.05) both characteristics. Our results demonstrate that ergot alkaloids (ET and DHET) can directly alter bovine sperm motility and morphology, which adds to our understanding of how ergot alkaloids may hinder cattle reproductive rates.
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