Association of some potential hormone response elements in human genes with the Alu family repeats.

Short interspersed repeats of the Alu family located in promoters of some human genes contain high-affinity binding sites for thyroid hormone receptor, retinoic acid receptor and estrogen receptor. The standard binding sites for the receptors represent variants of duplicated AGGTCA motif with different spacing and orientation (direct, DR, or inverted, IR), and Alu sequences were found to have functional DR-4, DR-2 or variant IR-3/IR-17 elements. In this study we analyzed distribution and abundance of the elements in a set of human genomic sequences from GenBank and their association with Alu repeats. Our results indicate that a major fraction of potentially active DR-4, DR-2 and variant IR-3/IR-17 elements in the genes is located within Alu repeats. Alu-associated DR-2 elements are conserved in primate evolution. However, very few Alu have potential DR-3 glucocorticoid-response elements. Gel-shift experiments with the probe (AUB) corresponding to the consensus Alu sequence just upstream of the RNA polymerase III promoter B-box and containing duplicated AGGTCA motif indicate that the probe interacts in a sequence-specific manner with human nuclear proteins which bind to standard IR-0, DR-1, DR-4 or DR-5 elements. The AUB sequence was also able to promote thyroid hormone-dependent trans-activation of a reporter gene. The results support the view that Alu retroposons played an important role in evolution of regulation of the primate gene expression by nuclear hormone receptors.     

Expression of the mosquitocidal toxins of Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis by recombinant Caulobacter crescentus, a vehicle for biological control of aquatic insect larvae.

In the quest for effective control of mosquitoes, attention has turned increasingly to strains of the bacteria Bacillus sphaericus and Bacillus thuringiensis subsp. israelensis, which produce potent toxins with specific mosquitocidal activities. However, sedimentation of the bacterial spores limits the duration of effective control after field application of these bacilli. We describe here the cloning of genes encoding the 51.4- and 41.9-kDa toxins from B. sphaericus 2297, the 100-kDa toxin from B. sphaericus SSII-1, and the 130-kDa toxin from B. thuringiensis subsp. israelensis into the broad-host-range plasmid pRK248 and the transfer of these genes for expression in Caulobacter crescentus CB15. The recombinant C. crescentus cells were shown to be toxic to mosquito larvae. Caulobacter species are ubiquitous microorganisms residing in the upper regions of aquatic environments and therefore provide the potential for prolonged control by maintaining mosquitocidal toxins in larval feeding zones.     

The pituitary-ovarian axis in dogs with remnant ovarian tissue

It can be difficult to confirm the presence of remnant ovarian tissue (ROT) in bitches that are presumed to be ovariohysterectomised. A GnRH stimulation test can be used to distinguish ovariectomised bitches from those in anoestrus, but it is uncertain whether the GnRH-induced changes in plasma LH and oestradiol concentrations that occur in intact bitches also occur in ROT-bitches. We report here eighteen ROT-bitches and compare the results of GnRH stimulation tests with those of six ovariectomised and six bitches in anoestrus.The basal (n = 17) and/or GnRH-stimulated (n = 18) plasma oestradiol concentration was above the detection limit of the assay, i.e., < 7 pmol/l, in all ROT-bitches but below the detection limit in all ovariectomised bitches. Basal plasma LH concentration was significantly higher in ROT-bitches (4.1 ± 0.7 μg/L) than those in anoestrus (0.64 ± 0.04 μg/L), and significantly lower than in ovariectomised bitches (20.2 ± 3.6 μg/L). Basal plasma LH concentration was relatively high in bitches in which there was a long interval between ovariectomy and appearance of oestrus. GnRH administration resulted in a significant increase in plasma LH and oestradiol concentrations in ROT-bitches. The GnRH-induced increase and subsequent decline in plasma LH concentration were significantly less in ROT-bitches than in either ovariectomised bitches or those in anoestrus. The GnRH-induced increase in plasma oestradiol concentration was significantly smaller in ROT-bitches than in those in anoestrus.In conclusion, the results of this study demonstrate that in dogs ROT is associated with noticeable changes in the pituitary-ovarian axis and suggest that a GnRH stimulation test may be used to distinguish between completely ovariectomised bitches and those with ROT.     

Two new cytotypes reinforce that <Emphasis Type="Italic">Micronycteris hirsuta</Emphasis> Peters, 1869 does not represent a monotypic taxon

Background

The genus Micronycteris is a diverse group of phyllostomid bats currently comprising 11 species, with diploid number (2n) ranging from 26 to 40 chromosomes. The karyotypic relationships within Micronycteris and between Micronycteris and other phyllostomids remain poorly understood. The karyotype of Micronycteris hirsuta is of particular interest: three different diploid numbers were reported for this species in South and Central Americas with 2n?=?26, 28 and 30 chromosomes. Although current evidence suggests some geographic differentiation among populations of M. hirsuta based on chromosomal, morphological, and nuclear and mitochondrial DNA markers, the recognition of new species or subspecies has been avoided due to the need for additional data, mainly chromosomal data.

Results

We describe two new cytotypes for Micronycteris hirsuta (MHI) (2n?=?26 and 25, NF?=?32), whose differences in diploid number are interpreted as the products of Robertsonian rearrangements. C-banding revealed a small amount of constitutive heterochromatin at the centromere and the NOR was located in the interstitial portion of the short arm of a second pair, confirmed by FISH. Telomeric probes hybridized to the centromeric regions and weakly to telomeric regions of most chromosomes. The G-banding analysis and chromosome painting with whole chromosome probes from Carollia brevicauda (CBR) and Phyllostomus hastatus (PHA) enabled the establishment of genome-wide homologies between MHI, CBR and PHA.

Conclusions

The karyotypes of Brazilian specimens of Micronycteris hirsuta described here are new to Micronycteris and reinforce that M. hirsuta does not represent a monotypic taxon. Our results corroborate the hypothesis of karyotypic megaevolution within Micronycteris, and strong evidence for this is that the entire chromosome complement of M. hirsuta was shown to be derivative with respect to species compared in this study.

     

Triggers of phytoplankton bloom dynamics in permanently eutrophic waters of a South African estuary

The permanently eutrophic Sundays Estuary experiences recurrent harmful algal blooms (HABs) of Heterosigma akashiwo (Raphidophyceae). This study aimed to identify the environmental variables shaping phytoplankton community composition and succession patterns during a typical spring/summer harmful algal bloom (HAB) period. Monitoring of abiotic and phytoplankton variables was undertaken over the period of a month in 2016. Surface water salinity corresponding to mesohaline conditions (9 to 12) was a prerequisite for site selection. During the study, two HABs (>550 µg Chl a l^?1) of H. akashiwo occurred, each lasting for approximately a week in duration. Analyses highlighted nutrient depletion (i.e. nitrate and phosphate concentrations) as the key constraint on bloom duration. When the density of H. akashiwo decreased, the community composition became more diverse with species belonging to Bacillariophyceae and Dinophyceae becoming more abundant; albeit to a lesser degree (<180 µg Chl a l^?1). Dissolved oxygen shifted from super-saturated conditions (>14 mg l^?1) during peak HAB conditions, to instances of bottom water oxygen depletion (2–4 mg l^?1) during the decay phase. These findings highlight the potential severity of transforming a catchment from natural to one that is highly regulated by agricultural practices, while also emphasising the need for management intervention.     

Weight loss is not mandatory for exercise-induced effects on health indices in females with metabolic syndrome

The aim of this study was to investigate the impact of moderate aerobic training on functional, anthropometric, biochemical, and health-related quality of life (HRQOL) parameters on women with metabolic syndrome (MS). Fifteen untrained women with MS performed moderate aerobic training for 15 weeks, without modifications of dietary behaviours. Functional, anthropometric, biochemical, control diet record and HRQOL parameters were assessed before and after the training. Despite body weight maintenance, the patients presented decreases in waist circumference (P = 0.001), number of MS components (P = 0.014), total cholesterol (P = 0.049), HDL cholesterol (P = 0.004), LDL cholesterol (P = 0.027), myeloperoxidase activity (P = 0.002) and thiobarbituric acid-reactive substances levels (P = 0.006). There were no differences in total energy, carbohydrate, protein and lipid intake pre- and post-training. Furthermore, improvements in the HRQOL subscales of physical functioning (P = 0.03), role-physical (P = 0.039), bodily pain (P = 0.048), general health (P = 0.046) and social functioning scoring (P = 0.011) were reported. Despite the absence of weight loss, aerobic training induced beneficial effects on functional, anthropometric, biochemical and HRQOL parameters in women with MS.     

DNA structure in which an adenine-cytosine mismatch pair forms an integral part of the double helix

Extensive studies using one- and two-dimensional 1H NMR at 500 MHz revealed that the oligonucleotide d(CGCCGCAGC) in solution at 5 degrees C forms a double helix under conditions of high salt (500 mM in NaCl, 1 mM sodium phosphate), low pH (pH 4.5), and high DNA concentration (4 mM in duplex). The presence of very strong nuclear Overhauser effects (NOEs) from base H8/H6 to sugar H2',H2" and the absence of NOE from base H8/H6 to sugar H3' suggested that the oligomer under these solution conditions forms a right-handed B-DNA double helix. The following lines of experimental evidence were used to conclude that C4 and A7 form an integral part of the duplex: (i) the presence of a NOESY cross-peak involving H8 of A7 and H8 of G8, (ii) the presence of a two-dimensional NOE (NOESY) cross-peak between H6 of C3 and H6 of C4, (iii) base protons belonging to C4 and A7 forming a part of the H8/H6---H1' cross-connectivity route, and (iv) the pattern of H8/H6---H2',H2" NOESY cross-connectivity based upon a B-DNA model requiring that both C4 and A7 form an integral part of the duplex. The possibility of an A-C pair involving H bonds was also examined. Two possible structural models of the duplex at pH 4.5 are proposed: in one model A-C pairing involves two H bonds, and in the other A-C pairing involves a single H bond.