Environmental benefits realized from eradication of the non-indigenous insect Anthonomus grandis Boheman, the cotton boll weevil

At least one third of the insecticide used in agriculture has been used to control the boll weevil in cotton. Historically, these insecticides have been toxic to humans and harsh on the environment. In addition, the intensive use of chemical insecticides to control the boll weevil results in the disruption of naturally occurring biological control factors that regulate other insect pest populations causing a chain reaction of secondary pest populations that require treatment followed by resurgence and repeat treatment. This situation has resulted in the development of resistance to insecticides, high control costs and unacceptable levels of chemical insecticide contamination in the environment. The boll weevil eradication program was instituted, in part, in an attempt to curtail the adverse environmental effects of traditional boll weevil control practices. A statistical analysis of 23 restricted use pesticides use in Louisiana cotton from 1991 through 2003 revealed that there was a significant change in the use of seven of these insecticides from the time before eradication (1991-1998) and during eradication (1999-2003) in Louisiana. Of these seven, five showed a significant decrease in use and two showed a significant increase in use. Impact quotients developed to take into account the annual use of each insecticide plus the toxicological values and environmental influence of each insecticide indicate that the insecticides with a significant change in use had a smaller mammalian toxicological impact quotient (MTIQ) during eradication than before eradication. The ecotoxicological impact quotient (EcoTIQ) increased dramatically during eradication as compared to before eradication and the environmental impact quotient (EnvIQ) increased slightly over the same period. In all cases, the MTIQ remained substantially lower than the EcoTIQ and EnvIQ in any given year and as eradication progressed and malathion use declined, so did the impact quotients and insecticide use, especially methyl parathion. As eradication of the boll weevil in Louisiana nears completion, a continued reduction in all three quotients is expected

Soil Compaction Thresholds for the M1A1 Abrams Tank: Field Study at Camp Minden, La. (Bulletin #891)

The purpose of this study was to establish critical soil compaction thresholds for M1A1 Abrams battle tank traffic in an effort to minimize soil physical properties that adversely affect vegetation regeneration.https://digitalcommons.lsu.edu/agcenter_bulletins/1004/thumbnail.jp

A covalent linker allows for membrane targeting of an oxylipin biosynthetic complex

A naturally occurring bifunctional protein from Plexaura homomalla links sequential catalytic activities in an oxylipin biosynthetic pathway. The C-terminal lipoxygenase (LOX) portion of the molecule catalyzes the transformation of arachidonic acid (AA) to the corresponding 8R-hydroperoxide, and the N-terminal allene oxide synthase (AOS) domain promotes the conversion of the hydroperoxide intermediate to the product allene oxide (AO). Small-angle X-ray scattering data indicate that in the absence of a covalent linkage the two catalytic domains that transform AA to AO associate to form a complex that recapitulates the structure of the bifunctional protein. The SAXS data also support a model for LOX and AOS domain orientation in the fusion protein inferred from a low-resolution crystal structure. However, results of membrane binding experiments indicate that covalent linkage of the domains is required for Ca2+-dependent membrane targeting of the sequential activities, despite the noncovalent domain association. Furthermore, membrane targeting is accompanied by a conformational change as monitored by specific proteolysis of the linker that joins the AOS and LOX domains. Our data are consistent with a model in which Ca2+-dependent membrane binding relieves the noncovalent interactions between the AOS and LOX domains and suggests that the C2-like domain of LOX mediates both protein-protein and protein-membrane interactions. © 2008 American Chemical Society

Widespread white matter and conduction defects in PSEN1-related spastic paraparesis

The mechanisms underlying PSEN1 mutation-associated spastic paraparesis (SP) are not clear. We compared diffusion and volumetric magnetic resonance measures between 3 persons with SP associated with the A431E mutation and 7 symptomatic persons with PSEN1 mutations without SP matched for symptom duration. We performed amyloid imaging and central motor and somatosensory conduction studies in one subject with SP. We found decreases in fractional anisotropy and increases in mean diffusivity in widespread white matter areas including the corpus callosum, occipital, parietal, and frontal lobes in PSEN1 mutation carriers with SP. Volumetric measures were not different and amyloid imaging showed low signal in sensorimotor cortex and other areas in a single subject with SP. Electrophysiological studies demonstrated both slowed motor and sensory conduction in the lower extremities in this same subject. Our results suggest that SP in carriers of the A431E PSEN1 mutation is a manifestation of widespread white matter abnormalities not confined to the corticospinal tract that is at most indirectly related to the mutation’s effect on APP processing and amyloid deposition

VASCULAR FLORA AND EDAPHIC CHARACTERISTICS OF SALINE PRAIRIES IN LOUISIANA

Volume: 4Start Page: 357End Page: 37