The relationship between balance and pitching error in college baseball pitchers

The objective of the study was to examine the relationship between balance and pitching error in college baseball pitchers. Sixteen college baseball pitchers, 9 National Association of Intercollegiate Athletics (NAIA) and 7 National Collegiate Athletic Association (NCAA) Division III, participated in the study. Balance ability, expressed as average sway velocity (deg.s(-1)), during dominant leg unilateral stance with eyes open and eyes closed was quantified for each subject utilizing the Balance Master System 7.04 (long force plate). Additionally, each subject underwent sensory organization testing on the SMART EquiTest System providing information regarding the effective use of the somatosensory, visual, and vestibular inputs. Pitching error was assessed with a high-speed video camera recorder during spring practice. A JUGS radar gun measured pitch velocity. The mean pitching error was 37.50 cm with a mean pitch velocity of 78 miles.h(-1) (35 m.s(-1)). No significant correlation was demonstrated between unilateral stance eyes open and pitching error (r = -0.24; p = 0.36) or unilateral stance eyes closed and pitching error (r = -0.29; p = 0.27). A significant negative correlation was demonstrated between sensory organization test 5 and pitching error (r = -0.50; p = 0.05) and between sensory organization test 5/1 and pitching error (r = -0.50; p = 0.05). Additionally, unilateral stance eyes closed demonstrated a positive correlation with pitch velocity (r = 0.52; p = 0.04). The results reveal that low levels of vestibular input utilization may lead to high levels of pitching error in college baseball pitchers.     

Phenylalanine 30 plays an important role in receptor binding of verotoxin-1

The homopentameric B subunit of verotoxin 1 (VT1) binds to the glycosphingolipid receptor globotriaosylceramide (Gb₃). We produced mutants with alanine substitutions for residues found near the cleft between adjacent subunits. Substitution of alanine for phenylalanine 30 (Phe-30) resulted in a fourfold reduction in B subunit binding affinity for Gb₃ and a 10-fold reduction in receptor density in a solid-phase binding assay. The interaction of wild-type and mutant B subunits with Pk trisaccharide in solution was examined by titration microcalorimetry. The carbohydrate binding of the mutant was markedly impaired compared with that of the wild type and was too weak to allow calculation of a binding constant. These results demonstrate that the mutation significantly impaired the carbohydrate-binding function of the B subunit. To ensure that the mutation had not caused a significant change in structure, the mutant B subunit was crystallized and its structure was determined by X-ray diffraction. Difference Fourier analysis showed that its structure was identical to that of the wild type, except for the substitution of alanine for Phe-30. The mutation was also produced in the VT1 operon, and mutant holotoxin was purified to homogeneity. The cytotoxicity of the mutant holotoxin was reduced by a factor of 10⁵ compared to that of the wild type in the Vero cell cytotoxicity assay. The results suggest that the aromatic ring of Phe-30 plays a major role in binding of the B subunit to the Galα1-4Galβ1-4Glc trisaccharide portion of Gb₃. Examination of the VT1 B crystal structure suggests two potential carbohydrate-binding sites which lie on either side of Phe-30.     

Treponema pallidum in gel microdroplets: a novel strategy for investigation of treponemal molecular architecture

Controversy exists regarding the constituents and antigenic properties of the Treponema pallidum outer membrane; a major point of contention concerns the cellular location(s) of the spirochaete's lipoprotein immunogens. To address these issues and circumvent problems associated with prior efforts to localize treponemal surface antigens, we developed a novel strategy for investigating T. pallidum molecular architecture. Virulent treponemes were encapsulated in porous agarose beads (gel microdroplets) and then probed in the presence or absence of Triton X-100. Intact., encapsulated treponemes were not labelled by monospecific antisera directed against four major T. pallidum lipoproteins or a candidate T. pailidum outer membrane protein (TpN50) with C-terminal sequence homology to Escherichia coli OmpA or by human or rabbit syphilitic serum. Each of these immunologic reagents, however, labelled encapsulated treponemes co-incubated with detergent. In contrast, antibodies generated against isolated T, pal-lidum outer membranes labelled intact organisms and the pattern of fluorescence was consistent with the distribution of rare outer membrane proteins visualized by freeze-fracture electron microscopy. In addition to providing strong evidence that the protein portions of treponemal lipoproteins are located within the periplasmic space, these studies have extended our understanding of the topographical relationships among T. pallidum cell envelope constituents. They also demonstrate the feasibility of generating antibodies against rare outer membrane proteins and detecting them on the surfaces of virulent treponemes.     

Hidden diversity of Ctenophora revealed by new mitochondrial COI primers and sequences

The mitochondrial gene cytochrome-c-oxidase subunit 1 (COI) is useful in many taxa for phylogenetics, population genetics, metabarcoding, and rapid species identifications. However, the phylum Ctenophora (comb jellies) has historically been difficult to study due to divergent mitochondrial sequences and the corresponding inability to amplify COI with degenerate and standard COI “barcoding” primers. As a result, there are very few COI sequences available for ctenophores, despite over 200 described species in the phylum. Here, we designed new primers and amplified the COI fragment from members of all major groups of ctenophores, including many undescribed species. Phylogenetic analyses of the resulting COI sequences revealed high diversity within many groups that was not evident from more conserved 18S rDNA sequences, in particular among the Lobata (Ctenophora; Tentaculata; Lobata). The COI phylogenetic results also revealed unexpected community structure within the genus Bolinopsis, suggested new species within the genus Bathocyroe, and supported the ecological and morphological differences of some species such as Lampocteis cruentiventer and similar undescribed lobates (Lampocteis sp. “V” stratified by depth, and “A” differentiated by colour). The newly designed primers reported herein provide important tools to enable researchers to illuminate the diversity of ctenophores worldwide via quick molecular identifications, improve the ability to analyse environmental DNA by improving reference libraries and amplifications, and enable a new breadth of population genetic studies.     

Developmental sex differences in calbindin‐D28K and calretinin immunoreactivity in the neonatal rat hypothalamus

The proteins calbindin‐D_28K and calretinin buffer intracellular calcium and are speculated to be involved in the integration of neuronal signaling. Using Western blot analysis, we compared the levels of calbindin‐D_28K and calretinin in the developing male and female rat hypothalamus on postnatal days (PN) 0, PN2, PN4, PN6, PN8, and PN10. Analysis of variance (ANOVA) of mean calbindin levels indicated a significant effect of sex (p ≤ .001) and age (p ≤ .0001) and a significant interaction (p ≤ .02). Post‐hoc Neuman‐Keuls analysis revealed that PN0 and PN2 males had significantly elevated calbindin levels over PN0 and PN2 females (p ≤ .05). ANOVA of mean calretinin levels from the same animals also indicated a significant effect of sex (p ≤ .002) and a significant interaction between sex and age (p ≤ .001). Post‐hoc analysis indicated males had significantly elevated calretinin levels over PN0, PN4 (p ≤ .05) and PN6 (p ≤ .01) females. Immunocytochemical analyses indicated calbindin‐immunopositive staining for cell bodies in the central subdivision of the medial preoptic nucleus, paraventricular nucleus, arcuate nucleus, and dorsomedial nucleus, and an area immediately surrounding the ventromedial nucleus (VMN). Calbindin immunoreactivity was absent from the ventrolateral VMN, but lightly stained cell bodies were observed in the dorsomedial VMN. The sex differences observed in calcium binding proteins parallel our previously observed sex differences in excitatory γ‐aminobutyric acid and glutamate early in development and may be related to mechanisms of sexual differentiation of the brain. © 2000 John Wiley & Sons, Inc. J Neurobiol 42: 315–322, 2000     

Borrelia burgdorferi complement regulator-acquiring surface protein 2 does not contribute to complement resistance or host infectivity

Borrelia burgdorferi, the pathogen of Lyme disease, cycles in nature through Ixodes ticks and mammalian hosts. At least five Complement Regulator-Acquiring Surface Proteins (BbCRASPs) are produced by B. burgdorferi, which are thought to assist spirochetes in host immune evasion. Recent studies established that BbCRASP-2 is preferentially expressed in mammals, and elicits robust antibody response in infected hosts, including humans. We show that BbCRASP-2 is ubiquitously expressed in diverse murine tissues, but not in ticks, reinforcing a role of BbCRASP-2 in conferring B. burgdorferi defense against persistent host immune threats, such as complement. BbCRASP-2 immunization, however, fails to protect mice from B. burgdorferi infection and does not modify disease, as reflected by the development of arthritis. An infectious BbCRASP-2 mutant was generated, therefore, to examine the precise role of the gene product in spirochete infectivity. Similar to wild type B. burgdorferi, BbCRASP-2 mutants remain insensitive to complement-mediated killing in vitro, retain full murine infectivity and induce arthritis. Quantitative RT-PCR assessment indicates that survivability of BbCRASP-2-deficient B. burgdorferi is not due to altered expression of other BbCRASPs. Together, these results suggest that the function of a selectively expressed B. burgdorferi gene, BbCRASP-2, is not essential for complement resistance or infectivity in the murine host.     

Zonation of shrubs in western Atlantic salt marshes

We explored the generality of the processes mediating shrub zonation in western Atlantic salt marshes by comparing the results of our experiments in Georgia, USA with previous studies from Rhode Island, USA. The shrub Borrichia frutescens dominates the terrestrial border of many Georgia salt marshes. Within the shrub zone, physical stress increased at lower elevations, shrubs at lower elevations were stunted, and experimentally reducing physical stress reduced shrub stunting. Below the shrub zone, physical stress increased further, and the grass Spartina alterniflora dominated. Transplant and neighbor-removal experiments indicated that the lower border of the shrub zone was set more by physical stress than by competition, but that the upper border of the grass zone was set primarily by competition with shrubs. Laboratory experiments indicated that S. alterniflora seedlings survived best and shrub seedlings worst in the flooded, salty treatment that mimicked low-marsh conditions. These processes are similar to those maintaining zonation patterns between the shrub Iva frutescens and the rush Juncus gerardi in Rhode Island salt marshes. However, markedly different processes appear to occur further to the north, where woody shrubs are absent from coastal marshes, and further to the south, where woody plants (mangroves) dominate coastal wetlands.     

The repeated evolution of stripe patterns is correlated with body morphology in the adaptive radiations of East African cichlid fishes

Color patterns are often linked to the behavioral and morphological characteristics of an animal, contributing to the effectiveness of such patterns as antipredatory strategies. Species‐rich adaptive radiations, such as the freshwater fish family Cichlidae, provide an exciting opportunity to study trait correlations at a macroevolutionary scale. Cichlids are also well known for their diversity and repeated evolution of color patterns and body morphology. To study the evolutionary dynamics between color patterns and body morphology, we used an extensive dataset of 461 species. A phylogenetic supertree of these species shows that stripe patterns evolved ~70 times independently and were lost again ~30 times. Moreover, stripe patterns show strong signs of correlated evolution with body elongation, suggesting that the stripes’ effectiveness as antipredatory strategy might differ depending on the body shape. Using pedigree‐based analyses, we show that stripes and body elongation segregate independently, indicating that the two traits are not genetically linked. Their correlation in nature is therefore likely maintained by correlational selection. Lastly, by performing a mate preference assay using a striped CRISPR‐Cas9 mutant of a nonstriped species, we show that females do not differentiate between striped CRISPR mutant males and nonstriped wild‐type males, suggesting that these patterns might be less important for species recognition and mate choice. In summary, our study suggests that the massive rates of repeated evolution of stripe patterns are shaped by correlational selection with body elongation, but not by sexual selection.