Are Pfiesteria species toxicogenic? Evidence against production of ichthyotoxins by Pfiesteria shumwayae

The estuarine genus Pfiesteria has received considerable attention since it was first identified and proposed to be the causative agent of fish kills along the mid-Atlantic coast in 1992. The presumption has been that the mechanism of fish death is by release of one or more toxins by the dinoflagellate. In this report, we challenge the notion that Pfiesteria species produce ichthyotoxins. Specifically, we show that (i) simple centrifugation, with and without ultrasonication, is sufficient to detoxify water of actively fish-killing cultures of Pfiesteria shumwayae, (ii) organic extracts of lyophilized cultures are not toxic to fish, (fit) degenerate primers that amplify PKS genes from several polyketide-producing dinoflagellates failed to yield a product with A shumwayae DNA or cDNA, and (iv) degenerate primers for NRPS genes failed to amplify any NRPS genes but (unexpectedly) yielded a band (among several) that corresponded to known or putative PKSs and fatty acid synthases. We conclude that P. shumwayae is able to kill fish by means other than releasing a toxin into bulk water. Alternative explanations of the effects attributed to Pfiesteria are suggested

General Minimal Flavor Violation

A model independent study of the minimal flavor violation (MFV) framework is presented, where the only sources of flavor breaking at low energy are the up and down Yukawa matrices. Two limits are identified for the Yukawa coupling expansion: linear MFV, where it is truncated at the leading terms, and nonlinear MFV, where such a truncation is not possible due to large third generation Yukawa couplings. These are then resummed to all orders using non-linear sigma-model techniques familiar from models of collective breaking. Generically, flavor diagonal CP violating (CPV) sources in the UV can induce O(1) CPV in processes involving third generation quarks. Due to a residual U(2) symmetry, the extra CPV in B_d-\bar B_d mixing is bounded by CPV in B_s-\bar B_s mixing. If operators with right-handed light quarks are subdominant, the extra CPV is equal in the two systems, and is negligible in processes involving only the first two generations. We find large enhancements in the up type sector, both in CPV in D-\bar D mixing and in top flavor violation.Comment: 5 pages and no figure

Genetic variation and exercise-induced muscle damage: implications for athletic performance, injury and ageing.

Prolonged unaccustomed exercise involving muscle lengthening (eccentric) actions can result in ultrastructural muscle disruption, impaired excitation-contraction coupling, inflammation and muscle protein degradation. This process is associated with delayed onset muscle soreness and is referred to as exercise-induced muscle damage. Although a certain amount of muscle damage may be necessary for adaptation to occur, excessive damage or inadequate recovery from exercise-induced muscle damage can increase injury risk, particularly in older individuals, who experience more damage and require longer to recover from muscle damaging exercise than younger adults. Furthermore, it is apparent that inter-individual variation exists in the response to exercise-induced muscle damage, and there is evidence that genetic variability may play a key role. Although this area of research is in its infancy, certain gene variations, or polymorphisms have been associated with exercise-induced muscle damage (i.e. individuals with certain genotypes experience greater muscle damage, and require longer recovery, following strenuous exercise). These polymorphisms include ACTN3 (R577X, rs1815739), TNF (-308 G>A, rs1800629), IL6 (-174 G>C, rs1800795), and IGF2 (ApaI, 17200 G>A, rs680). Knowing how someone is likely to respond to a particular type of exercise could help coaches/practitioners individualise the exercise training of their athletes/patients, thus maximising recovery and adaptation, while reducing overload-associated injury risk. The purpose of this review is to provide a critical analysis of the literature concerning gene polymorphisms associated with exercise-induced muscle damage, both in young and older individuals, and to highlight the potential mechanisms underpinning these associations, thus providing a better understanding of exercise-induced muscle damage

YOGA AS THE SOLUTION TO MOVEMENT LIMITATIONS IN BASEBALL PITCHERS

Tynniesia M. Wilson, Kathleen S. Thomas, Matthew Rein, Donna Wolf. Norfolk State University, Norfolk, VA. BACKGROUND: Baseball pitchers often face physical limitations that prevent them from performing at their complete capabilities. The cause of such deficits in lack of mobility is often attributed to individual risk factors, injury, or some combination of both. The purpose of this study was to investigate how yoga can be used as an activity to promote physical health through psychological adaptations. METHODS: Nine competition eligible NCAA Division 1 baseball pitchers from Norfolk State University participated in this study (ages 18-23y). Each was given a set of questions to assess pre-intervention levels of flexibility involvement and relevant injury history. Following initial testing for Functional Movement Screen (FMS) scores, pitchers were expected to attend regular strength training, practices, and prehab, along with additional yoga sessions. Post-test FMS scores provided indication of whether the yoga activities made for positive improvements in mobility. Two final surveys detailed psychological adaptations and descriptive perceptions of the test validity. Experimental paired t-test (p ﹤ 0.05) was used to interpret significant differences in the FMS data. RESULTS: A statistical significance in the difference of means was not recognized in any of the seven individual screening components. A breakdown of the overall FMS scores reveals a slightly greater mean in the pre-tests (M= 16.89, SD=2.472) than for the post-tests (M=16.78, SD= 1.716). The difference in means for the test samples paired (M=0.111, SD= 2.421) had the greatest statistical insignificance at p= 0.894. End-of-intervention survey results supported psychological adaptations with retention in yoga participation and a 62.5% perception that yoga has been a beneficial activity for movement quality. CONCLUSIONS: The results of the FMS scores suggest that yoga does not play a significant role in changing total scores. In contrast, survey data reflects continued participation in stretching exercises for improved mobility, as well as general agreement that yoga made for better movement. While there were adaptations psychologically, they did not cause positive adaptations physically. This movement based insight could ensure the athletes are meeting short and long-term movement goals for lifelong health