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Opuntia robusta has hermaphroditic, dioecious, and trioecious populations. To enhance our understanding of this breeding system diversity, we compared the reproductive output of males, females, and hermaphrodites in a trioecious population using field evaluations, controlled crosses, and progeny tests. Unisexuals were fully sterile in one sex function. Hermaphrodites were fully fertile for both functions. Consistent with the sex-allocation theory, unisexuality increased the quality and quantity (in males) of the gametes of the functional sex, relative to those of hermaphrodites, probably explained by maternal and paternal effects. The increase was higher in males than in females, suggesting a more expensive female function. Theoretically, this disproportional increase is required for unisexuals to invade a hermaphroditic population with prior selfing, negligible pollen discounting, and undetectable inbreeding depression, features found in O. robusta, therefore helping to explain dioecious populations. However, in the study population, the actual seed output of females was lower and had a higher variance than that of hermaphrodites, which also reproduce through pollen. Unisexuals are unlikely to be maintained by their actual reproductive output in this pollen-limited environment. Hermaphrodites may persist in this population by producing their seeds autonomously and by reducing interspecific fertilization by prior selfing and ovule discounting. 相似文献
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Bruno Manta Martín Hugo Cecilia Ortiz Gerardo Ferrer-Sueta Madia Trujillo Ana Denicola 《Archives of biochemistry and biophysics》2009,484(2):146-154
Peroxiredoxin 2 (Prx2) is a 2-Cys peroxiredoxin extremely abundant in the erythrocyte. The peroxidase activity was studied in a steady-state approach yielding an apparent KM of 2.4 μM for human thioredoxin and a very low KM for H2O2 (?0.7 μM). Rate constants for the reaction of peroxidatic cysteine with the peroxide substrate, H2O2 or peroxynitrite, were determined by competition kinetics, k2 = 1.0 × 108 and 1.4 × 107 M−1 s−1 at 25 °C and pH 7.4, respectively. Excess of both oxidants inactivated the enzyme by overoxidation and also tyrosine nitration and dityrosine were observed with peroxynitrite treatment. Prx2 associates into decamers (5 homodimers) and we estimated a dissociation constant Kd < 10−23 M4 which confirms the enzyme exists as a decamer in vivo. Our kinetic results indicate Prx2 is a key antioxidant enzyme for the erythrocyte and reveal red blood cells as active oxidant scrubbers in the bloodstream. 相似文献
106.
The Indiana bat (Myotis sodalis) is a highly endangered vespertilionid bat whose distribution is associated with limestone caves in the eastern United States.
We present nine new polymorphic nuclear microsatellite markers for Myotis sodalis developed using an enriched library method. A total of 62 M. sodalis from two populations were used to estimate genetic diversity parameters. In M. sodalis, the number of alleles observed for each locus ranged from 17 to 48 alleles and expected heterozygosity ranged from 0.894
to 0.973. The 9 microsatellite markers were also tested on M. gricescens, M. leibii, M. lucifugus, and M. septentrionalis. These polymorphic microsatellite markers provide a valuable tool for investigating the population genetics of these species
and will provide important genetic data useful for the conservation and recovery of the endangered Indiana bat. 相似文献
107.
Rolando Carrisoza Carolina Salvador Norma A. Bobadilla Joyce Trujillo Laura I. Escobar 《Histochemistry and cell biology》2010,133(2):189-199
Potassium (K+) channels participate in K+ secretion, K+ recycling, and cell volume regulation and help to maintain the resting potential in mammalian kidneys. Previously, we identified
a set of voltage-gated K+ channels (Kv1) in the inner medullary collecting duct of the rat kidney. In the present work, we identified the voltage-gated
K+ channel ether-à-go-go-related gene (ERG) in the rat kidney. mRNAs of ERG1a and its N-terminal splice-variant ERG1b were detected. Immunoblots of the cortex and medulla revealed two molecular mass proteins of 135 and 80 kDa, consistent in
size with the nonglycosylated ERG1a and ERG1b isoforms, respectively. However, bands of 155 and 95 kDa, corresponding to mature
glycosylated ERG1a and ERG1b, respectively, were also observed. In our immunohistochemical experiments, we could not differentiate
the ERG1 isoforms because we used an antibody against a carboxy-terminal epitope. ERG1 was differentially localized in specific
nephron segments: its localization was intracellular in the proximal tubule and medullary collecting ducts and in the apical
membranes in the distal convoluted and connecting tubules. ERG1 was also abundant in glomerular arterioles and renal vessels.
In summary, ERG1 displays a heterogeneous distribution in the rat kidney. 相似文献
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Background
It is a well-known phenomenon that some patients with acute left or right hemisphere stroke show a deviation of the eyes (Prévost's sign) and head to one side. Here we investigated whether both right- and left-sided brain lesions may cause this deviation. Moreover, we studied the relationship between this phenomenon and spatial neglect. In contrast to previous studies, we determined not only the discrete presence or absence of eye deviation with the naked eye through clinical inspection, but actually measured the extent of horizontal eye-in-head and head-on-trunk deviation. In further contrast, measurements were performed early after stroke onset (1.5 days on average). 相似文献110.
Lorena Carro Rüdiger Pukall Cathrin Spröer Reiner M. Kroppenstedt Martha E. Trujillo 《Antonie van Leeuwenhoek》2013,103(6):1245-1254
A filamentous actinomycete strain designated CR18T was isolated on humic acid agar from the rhizosphere of a Pisum sativum plant collected in Spain. This isolate was observed to grow optimally at 28 °C, pH 7.0 and in the presence of 5 % NaCl. Phylogenetic analyses based on the 16S rRNA gene sequence indicated a close relationship with the type strains of Micromonospora chersina and Micromonospora endolithica. A further analysis based on a concatenated DNA sequence stretch of 4,523 bp that included partial sequences of the atpD, gyrB, recA, rpoB and 16S rRNA genes clearly differentiated the new strain from recognized Micromonospora species compared. DNA–DNA hybridization studies further supported the taxonomic position of strain CR18T as a novel genomic species. Chemotaxonomic analyses which included whole cell sugars, polar lipids, fatty acid profiles and menaquinone composition confirmed the affiliation of the new strain to the genus Micromonospora and also highlighted differences at the species level. These studies were finally complemented with an array of physiological tests to help differentiate between the new strain and its phylogenetic neighbours. Consequently, strain CR18T (= CECT 7890T = DSM 45598T) is proposed as the type strain of a novel species, Micromonospora halotolerans sp. nov. 相似文献