Conformational and intramolecular hydrogen bonding effects on post-emergence and pre-emergence selectivities of herbicidal pyrrole dicarboxylates

Dimethyl 2-methyl-5-(chloropyridin-2-yl)pyrrole-3,4-dicarboxylates in which the chlorine atom is substituted at different positions of the pyridine ring have widely varying biological properties. The 3-chloro analog (I) is a post-emergence and pre-emergence herbicide, the 4- and 5-chloro analogs (II, III) are post-emergence herbicides but not pre-emergence, and the 6-chloro analog (IV) is inactive. Computer graphic and molecular mechanics analyses of their molecular conformations showed that the 4- and 5-chloro analogs adopt a coplanar, intramolecularly hydrogen bonded conformation whereas the 3-chloro analog does not. High-level quantum mechanical calculations of the conformational preferences of related model systems were in agreement with these results. Based on this, II and III were predicted to have higher octanol/water partition coefficients relative to I, leading to higher soil binding and weaker xylem transport, hence their observed weaker pre-emergence activities. Experimental measurements of octanol/water partition coefficients, soil binding, and infrared hydrogen bonding studies verified these predictions. Molecular modeling techniques are usually used for designing compounds to fit enzyme active sites and designing putative receptor models. This study demonstrates the usefulness of these techniques for dealing with transport problems.     

Comparison between radiography and computed tomography for diagnosis of equine skull fractures

The equine head is a complex structure prone to traumatic injuries. To determine the value and limitations of radiography and (CT) for the diagnosis of skull fracture, the differences between the two modalities were described. Two observers retrospectively reviewed the radiographic and CT images of 18 horses with a skull fracture. To allow direct comparison between the two modalities, a simplified fracture classification system was used. In 3/18 cases the evaluation of the radiographic examination concluded no injuries visible. In 2/15 cases soft tissue involvement was not detected and in 7/15 cases the extension of the fracture was underestimated with radiography. Radiography classified 4/10 multiple fractures incorrectly as single fracture and 5/15 comminuted fractures on CT were diagnosed as simple fracture with radiography. The number of fragments was underestimated with radiography in 14/15 cases. In conclusion, radiography is able to diagnose a skull fracture in most cases. Skull fractures however are not similarly classified after radiographic and CT evaluation, which causes a difference in interpretation and perception of the fractures. Therefore, CT should be the modality of choice for surgical planning and prognosis.     

Computed tomography of nuchal ligament and semispinalis capitis tendon avulsions in a foal

Head trauma is a common injury in young horses. This case report describes a 10‐week‐old Thoroughbred foal with an open wound following trauma to the poll region, showing abnormal head carriage and depression. A computed tomography (CT) study was performed under general anaesthetic (GA). This identified a complete avulsion of the nuchal ligament (NL) and partial avulsions of the left and right semispinalis capitis (SS) tendons. Following diagnosis and conservative treatment the foal made a good recovery and 18 months later the filly had no detectable neurological or physical abnormalities. Computed tomography enabled an accurate and rapid diagnosis of a novel injury.     

Heat Shock Protein Regulation in Rainbow Trout,Oncorhynchus mykiss,is Altered by Dietary Soybean Meal Inclusion and Anti‐Phopholipase A2 Antibody

Heat shock proteins (Hsps) can promote integrity of damaged intestinal epithelial tissues. The aim of this study was to determine the effects of a commercially available anti‐phospholipase A₂ antibody on growth, feed efficiency, Hsp expression, and intestinal health of rainbow trout fed diets containing high levels of soybean meal (SBM). Six practical‐type diets (45% protein; 15% fat) were formulated to contain 0, 17.5, or 35% SBM with and without antibody. Each diet was fed to three replicate tanks of fish (20 fish/tank; initial weight 21 g) for 9 wk. RNA was isolated from liver and intestinal tissues (n = 3/tank) to detect alterations in Hsp 27, Hsp 70, and Hsp 90 expression. Fish fed a diet containing 35% SBM had decreased growth and intestinal damage. Hsp 27 and Hsp 90 mRNA was elevated in fish fed 35% SBM. Fish fed 35% SBM with antibody had lower Hsp 90 mRNA expression than fish without antibody. These data indicate that feeding rainbow trout high levels of SBM alters the expression of some Hsps and anti‐phospholipase A₂ antibody supplementation does not normalize growth or prevent distal enteritis in fish fed 35% SBM.     

Spring home ranges of white bass in irrigation reservoirs of the Republican River Basin, Nebraska

Abstract –  Fishery biologists have documented small home ranges, relative to available habitat, for many littoral freshwater fishes. Home ranges for pelagic species, such as white bass Morone chrysops , are generally not well described, yet are thought to be large. We studied white bass movement using acoustic telemetry in two irrigation reservoirs of the Republican River basin in south-western Nebraska. Acoustic transmitters were implanted in fall of the previous year and tracking occurred a minimum of once per week throughout spring (mid-March to May) 2007 and 2008. Linear home ranges were calculated from observed locations of individual fish. Twelve of the twenty-seven tagged fish with at least five locations exhibited localised home ranges throughout the spring whereas the remaining fish exhibited home ranges extending across large portions of each reservoir. Home range size was not correlated with fish size or condition.     

Successful rehabilitation and release of a powerful owl chick with suspected rodenticide poisoning

The successful rehabilitation and release of raptor chicks can be challenging, especially when the chicks are still in the post-fledging dependency period. Here, we report on a recently fledged powerful owl chick that was held in care for 33 days before being successfully reunited with its parents. We document the steps undertaken during the entire process from collection from the wild to post-release monitoring and recommend clinical procedures for treatment of raptors entering veterinary facilities. Success of this rehabilitation was facilitated by early care and treatment for potential rodenticide poisoning, as well as the integration of citizen scientists monitoring the family unit in the field while the chick was in care and during the post-release period. Given the emerging evidence of widespread rodenticide poisoning in raptors both in Australia and globally, it is critical to suspect all raptors may have been exposed to anticoagulant rodenticides and commence treatment with vitamin K immediately. Routine treatment for rodenticides early increases the probability of successful recovery post-trauma as well as reducing the time in treatment as much as possible.     

The Effect of Vitamins on Weight Gain and Organ Production in the Sea Urchin,Lytechinus variegatus (Echinodermata: Echinoidea)

We investigated the requirements for a commercial vitamin premix in diets of Lytechinus variegatus. Small L. variegatus (ca. 28 mm diameter) were collected from Saint Joseph Bay, Florida, and acclimated to laboratory conditions (32 ppt salinity, 22 C, 12:12 photoperiod) for 3 wk, then placed individually into plastic mesh cages (n = 16 per treatment). Sixteen urchins were dissected to obtain initial weights of organs (gut, gonad, test). Each treatment was fed one of five semipurified diets supplemented with levels of a commercial shrimp vitamin premix ranging from 0 to 0.9% dry weight. At 4‐wk intervals, wet weights and test diameters were measured. At 16 wk, urchins were dissected and organs weighed. Significant weight gain and 100% survival was observed with all diets. At 16 wk, urchins fed 0% vitamin premix exhibited no noticeable pathology but had significantly less weight gain than those fed the 0.6% vitamin premix. Those fed the 0.6% vitamin premix had significantly greater weight gain than all other diets (P < 0.0001). Gonad weights increased in all treatments, but did not vary significantly. Under the conditions of this study, L. variegatusexhibited a satisfactory nutritional response. Experiments are planned to determine specific dietary vitamin requirements for L. variegatus.