691 research outputs found
The Use of a Cap-mounted Tri-axial Accelerometer for Measurement of Distance, Lap Times and Stroke Rates in Swim Training
This paper will report some of the findings from a trial which recorded accelerometer data from six elite level swimmers (three female and three male, varying primary event stroke and distance) over the course of a regular 15 week training block. Measurements from a head-mounted accelerometer are used to determine when the athlete is swimming, marking of turning points (and therefore distance and lap-time measurements), and is processed by frequency analysis to determine stroke-rate. Comparison with video where available, and with training plans and literature where not, have proven this method to be accurate and reliable for determining these performance metrics. The primary objective of this project was to develop a low-cost, simple and highly usable system for use in swim coaching, feedback from elite coaches has indicated that development of this could be an extremely useful addition to their training regime
Members of the chloride intracellular ion channel protein family demonstrate glutaredoxin-like enzymatic activity
Β© 2015 Al Khamici et al. The Chloride Intracellular Ion Channel (CLIC) family consists of six evolutionarily conserved proteins in humans. Members of this family are unusual, existing as both monomeric soluble proteins and as integral membrane proteins where they function as chloride selective ion channels, however no function has previously been assigned to their soluble form. Structural studies have shown that in the soluble form, CLIC proteins adopt a glutathione S-transferase (GST) fold, however, they have an active site with a conserved glutaredoxin monothiol motif, similar to the omega class GSTs. We demonstrate that CLIC proteins have glutaredoxin-like glutathione-dependent oxidoreductase enzymatic activity. CLICs 1, 2 and 4 demonstrate typical glutaredoxin-like activity using 2-hydroxyethyl disulfide as a substrate. Mutagenesis experiments identify cysteine 24 as the catalytic cysteine residue in CLIC1, which is consistent with its structure. CLIC1 was shown to reduce sodium selenite and dehydroascorbate in a glutathione-dependent manner. Previous electrophysiological studies have shown that the drugs IAA-94 and A9C specifically block CLIC channel activity. These same compounds inhibit CLIC1 oxidoreductase activity. This work for the first time assigns a functional activity to the soluble form of the CLIC proteins. Our results demonstrate that the soluble form of the CLIC proteins has an enzymatic activity that is distinct from the channel activity of their integral membrane form. This CLIC enzymatic activity may be important for protecting the intracellular environment against oxidation. It is also likely that this enzymatic activity regulates the CLIC ion channel function
L,L-Diaminopimelate Aminotransferase from Chlamydomonas reinhardtii: A Target for Algaecide Development
In some bacterial species and photosynthetic cohorts, including algae, the enzyme
l,l-diaminopimelate aminotransferase
(DapL) (E.C. 2.6.1.83) is involved in the anabolism of the essential amino acid
L-lysine. DapL catalyzes the conversion of
tetrahydrodipicolinate (THDPA) to
l,l-diaminopimelate
(l,l-DAP), in one step bypassing the
DapD, DapC and DapE enzymatic reactions present in the acyl DAP pathways. Here
we present an in vivo and in vitro
characterization of the DapL ortholog from the alga Chlamydomonas
reinhardtii (Cr-DapL). The in
vivo analysis illustrated that the enzyme is able to functionally
complement the E. coli dap auxotrophs and was essential for
plant development in Arabidopsis. In vitro, the enzyme was able
to inter-convert THDPA and l,l-DAP, showing
strong substrate specificity. Cr-DapL was dimeric in both
solution and when crystallized. The structure of Cr-DapL was
solved in its apo form, showing an overall architecture of a
Ξ±/Ξ² protein with each monomer in the dimer adopting a pyridoxal
phosphate-dependent transferase-like fold in a V-shaped conformation. The active
site comprises residues from both monomers in the dimer and shows some
rearrangement when compared to the apo-DapL structure from
Arabidopsis. Since animals do not possess the enzymatic machinery necessary for
the de novo synthesis of the amino acid
l-lysine, enzymes involved in this pathway are
attractive targets for the development of antibiotics, herbicides and
algaecides
Osteoarticular Infection in Three Young Thoroughbred Horses Caused by a Novel Gram Negative Cocco-Bacillus
Β© 2020 Bernard J. Hudson et al. We describe three cases of osteoarticular infection (OAI) in young thoroughbred horses in which the causative organism was identified by MALDI-TOF as Kingella species. The pattern of OAI resembled that reported with Kingella infection in humans. Analysis by 16S rRNA PCR enabled construction of a phylogenetic tree that placed the isolates closer to Simonsiella and Alysiella species, rather than Kingella species. Average nucleotide identity (ANI) comparison between the new isolate and Kingella kingae and Alysiella crassa however revealed low probability that the new isolate belonged to either of these species. This preliminary analysis suggests the organism isolated is a previously unrecognised species
Imperfection works: Survival, transmission and persistence in the system of Heliothis virescens ascovirus 3h (HvAV-3h), Microplitis similis and Spodoptera exigua
Ascoviruses are insect-specific large DNA viruses that mainly infect noctuid larvae, and are transmitted by parasitoids in the fields. Heliothis virescens ascovirus 3h (HvAV-3h) has been recently isolated from Spodoptera exigua, without parasitoid vector identified previously. Here we report that Microplitis similis, a solitary endoparasitoid wasp, could transmit HvAV-3h between S. exigua larvae in the laboratory. When the female parasitoid wasp acquired the virus and served as a vector, the period of virion viability on the ovipositor was 4.1βΒ±β1.4 days. Infected host larvae were still acceptable for egg laying by parasitoids, and the parasitoids thereafter transmitted virus to healthy hosts. Virus acquisition occurred only from donor hosts between 3 and 9 days post infection. The peak of virus acquisition (80.9βΒ±β6.3%) was found when M. similis wasps oviposited in larvae that had been inoculated with the virus 7 days previously. When virus infection of the host took place during the life cycle of the parasitoid wasp, it caused 1- to 4-day-old immature parasitoids death in the host, whilst a small proportion of 5- to 6-day-old and the majority of 7-day-old parasitoids larvae survived from the virus-infected hosts. Viral contamination did not reduce the life span or fecundity of female M. similis
GROWTH OF CERRADO NATIVE SPECIES AND OF Vetiveria zizanioides IN COLLUVIUM OF GULLIES
Taxas de germina\ue7\ue3o de sementes, sobreviv\ueancia e
crescimento de plantas, par\ue2metros estes avaliados no presente
estudo, s\ue3o informa\ue7\uf5es essenciais para a
caracteriza\ue7\ue3o do potencial biol\uf3gico de esp\ue9cies
para uso em processos de recupera\ue7\ue3o de \ue1reas
degradadas. A falta de conhecimento sobre tais aspectos em
esp\ue9cies nativas t\ueam justificado o uso de plantas
ex\uf3ticas na revegeta\ue7\ue3o de vo\ue7orocas em todo o
Brasil. Entretanto, especialmente em locais sujeitos \ue0 grande
sazonalidade clim\ue1tica e sobre solos oligotr\uf3ficos,
esp\ue9cies ex\uf3ticas nem sempre apresentam bom desempenho,
levando o empreendimento de revegeta\ue7\ue3o ao insucesso ou
elevando consideravelmente a necessidade de aplica\ue7\ue3o de
tratos culturais. Com o objetivo de ampliar os conhecimentos sobre o
potencial biol\uf3gico para revegeta\ue7\ue3o em vo\ue7orocas
de plantas nativas do cerrado e de uma gram\uednea ex\uf3tica, que
vem sendo amplamente usada em projetos de conten\ue7\ue3o de
eros\ue3o, pl\ue2ntulas e touceiras das esp\ue9cies nativas
Cratylia argentea (Desv.) Kuntze e Echinolaena inflexa (Poir.)
Chase, e da ex\uf3tica Vetiveria zizanioides (L.) Nash foram
transferidas para o col\ufavio de uma vo\ue7oroca no munic\uedpio
de Ouro Preto - MG, onde permaneceram durante a esta\ue7\ue3o seca
de 2010 sem aplica\ue7\ue3o de fertilizantes ou
irriga\ue7\ue3o. Em blocos ao acaso, parcelas de 1 x 1 m receberam
aleatoriamente quatro tratamentos de plantio: touceiras de Echinolaena
inflexa ou de Vetiveria zizanioides; e touceiras destas gram\uedneas
em cons\uf3rcio com a leguminosa arbustiva Cratylia argentea. Todas
as gram\uedneas e 73% das pl\ue2ntulas da leguminosa sobreviveram.
Como esperado, a cobertura verde de Echinolaena Inflexa diminuiu ao
longo da esta\ue7\ue3o seca, tendo, entretanto, rebrotado ap\uf3s
as primeiras chuvas. Vetiveria zizanioides manteve a \ue1rea foliar
ativa e apresentou crescimento significativo no per\uedodo. Cratylia
argentea apresentou altas taxas de germina\ue7\ue3o de sementes e
de crescimento, entretanto, nodula\ue7\ue3o ocorreu em apenas dois
indiv\uedduos. Assim, n\ue3o houve influ\ueancia da leguminosa no
crescimento das gram\uedneas. Os resultados indicam que tanto as
esp\ue9cies nativas do cerrado como a gram\uednea ex\uf3tica
possuem alto potencial para revegeta\ue7\ue3o em col\ufavio de
vo\ue7oroca, tendo sobrevivido ao per\uedodo cr\uedtico de seca e
sobre substrato oligotr\uf3fico sem adi\ue7\ue3o de fertilizantes
ou irriga\ue7\ue3o.Rates of seed germination, plant survival and growth, as measured in
the present study, are essential parameters to characterize the
biological potential of species for the restoration of degraded areas.
The lack of knowledge about these aspects in native species has
justified the use of exotic plants in Brazilian gullies revegetation.
However, especially in places subject to highly seasonal climate and on
oligotrophic soils, exotic species do not always perform well, leading
to revegetation failure or significantly increasing the cultivation
care needs. To improve the knowledge concerning to the biological
potencial of cerrado native species and of an exotic grass which has
been used for erosion contention, in the present study, seedlings and
clumps of native cerrado species, Cratylia argentea (Desv.) Kuntze
and Echinolaena inflexa (Poir.) Chase, and of the exotic grass
Vetiveria zizanioides (L.) Nash, were transferred to a gully
colluvium in Ouro Preto, Minas Gerais state, where they remained during
the dry season of 2010 without application of fertilizers or
irrigation. In randomized block design, plots of 1 x 1 m received four
planting treatments: clumps of Echinolaena inflexa or Vetiveria
zizanioides, and clumps of these grasses intercropped with the legume
Cratylia argentea. All grasses and 73% of the legume seedlings
survived. As expected, the green cover of Echinolaena inflexa decreased
throughout the dry season, however, showing regrowth after the first
rains. Leaf area of Vetiveria zizanioides remained active and grew
significantly in the period. Cratylia argentea showed high rates of
germination and growth; however, nodulation occurred in only two
individuals. Thus, there was no influence of the legume on grasses
growth. Results indicate that both native species and the exotic grass
tested are potential successful plants for gullies replanting. Plants
survived and grew on low nutrient substrate and during the critical
period of drought without any fertilizer or irrigation application
Diversifying Selection Underlies the Origin of Allozyme Polymorphism at the Phosphoglucose Isomerase Locus in Tigriopus californicus
The marine copepod Tigriopus californicus lives in intertidal rock pools along the Pacific coast, where it exhibits strong, temporally stable population genetic structure. Previous allozyme surveys have found high frequency private alleles among neighboring subpopulations, indicating that there is limited genetic exchange between populations. Here we evaluate the factors responsible for the diversification and maintenance of alleles at the phosphoglucose isomerase (Pgi) locus by evaluating patterns of nucleotide variation underlying previously identified allozyme polymorphism. Copepods were sampled from eleven sites throughout California and Baja California, revealing deep genetic structure among populations as well as genetic variability within populations. Evidence of recombination is limited to the sample from Pescadero and there is no support for linkage disequilibrium across the Pgi locus. Neutrality tests and codon-based models of substitution suggest the action of natural selection due to elevated non-synonymous substitutions at a small number of sites in Pgi. Two sites are identified as the charge-changing residues underlying allozyme polymorphisms in T. californicus. A reanalysis of allozyme variation at several focal populations, spanning a period of 26 years and over 200 generations, shows that Pgi alleles are maintained without notable frequency changes. Our data suggest that diversifying selection accounted for the origin of Pgi allozymes, while McDonald-Kreitman tests and the temporal stability of private allozyme alleles suggests that balancing selection may be involved in the maintenance of amino acid polymorphisms within populations
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