Alterations in the development of catecholamine turnover induced by perinatal methadone: Differences in central vs. peripheral sympathetic nervous systems

Administration of methadone to pregnant and nursing rats slows synaptogenesis of central cathcholaminergic systems in the offspring but accelerates the onset of synaptic function in peripheral sympathetic pathways. Norepinephrine turnover, assessed by inhibiting catecholamine biosynthesis with alpha-methyl-p-tyrosine, was elevated in cardiac sympathetic nerve terminals in rats exposed perinatally to methadone. In contrast, turnover was unchanged in noradrenergic and dopaminergic systems in the brain. Similar results were obtained when methadone was given directly to the pups during postnatal life. These data suggest that opiate-induced alterations of impulse flow and transmitter turnover in a given neuron population may determine whether the effects of perinatal methadone exposure result in facilitation or inhibition of synaptic development.     

Computerized tomography-guided stereotactic dentatotomy

The CT stereotactic technique of dentatotomy is described and illustrated with two examples. With this combined technique, ventriculography or pneumencephalography is no longer needed to determine the target point. In addition, due to the direct representation of anatomic structures in the CT, abnormal positions of the dentate nucleus may be taken into consideration in the determination of the target point and approach for the coagulation probe.     

Drainage-structuring of ancestral variation and a common functional pathway shape limited genomic convergence in natural high- and low-predation guppies

Studies of convergence in wild populations have been instrumental in understanding adaptation by providing strong evidence for natural selection. At the genetic level, we are beginning to appreciate that the re-use of the same genes in adaptation occurs through different mechanisms and can be constrained by underlying trait architectures and demographic characteristics of natural populations. Here, we explore these processes in naturally adapted high- (HP) and low-predation (LP) populations of the Trinidadian guppy, Poecilia reticulata. As a model for phenotypic change this system provided some of the earliest evidence of rapid and repeatable evolution in vertebrates; the genetic basis of which has yet to be studied at the whole-genome level. We collected whole-genome sequencing data from ten populations (176 individuals) representing five independent HP-LP river pairs across the three main drainages in Northern Trinidad. We evaluate population structure, uncovering several LP bottlenecks and variable between-river introgression that can lead to constraints on the sharing of adaptive variation between populations. Consequently, we found limited selection on common genes or loci across all drainages. Using a pathway type analysis, however, we find evidence of repeated selection on different genes involved in cadherin signaling. Finally, we found a large repeatedly selected haplotype on chromosome 20 in three rivers from the same drainage. Taken together, despite limited sharing of adaptive variation among rivers, we found evidence of convergent evolution associated with HP-LP environments in pathways across divergent drainages and at a previously unreported candidate haplotype within a drainage.     

Hypoglycemia following insulin and proinsulin. A comparison

The counterregulatory hormonal response to proinsulin-induced hypoglycemia was investigated in eight volunteers. Proinsulin cleared slower from the circulation than insulin. Hypoglycemia occurred slower (2P less than 0.005) and was prolonged, while the overall hypoglycemic activities were comparable. The antilipolytic effect of proinsulin was also prolonged (2P less than 0.001). The response of epinephrine to hypoglycemia was less pronounced after proinsulin (2P less than 0.05). The amount of epinephrine was correlated to the rate of fall in plasma glucose (P less than 0.005). The production of lactate induced by beta-stimulation was also correlated to the fall of glucose (P less than 0.005). The responses of prolactin (2P less than 0.02), norepinephrine (2P less than 0.02), cortisol, and growth hormone were attenuated following proinsulin. The decreases of serum potassium and serum phosphate (2P less than 0.05) were less pronounced. Symptoms like sweating (2P less than 0.01) and dizziness (2P less than 0.01) were milder after proinsulin. It is concluded that the rate of fall in glucose concentration determines the differing counterregulatory responses. We don't relate the differing counterregulatory responses to special insulin-like properties of proinsulin, but to the slower kinetics which is emphasized by the intravenous bolus injection.     

Deep haplotype analyses of target-site resistance locus ACCase in blackgrass enabled by pool-based amplicon sequencing

Rapid adaptation of weeds to herbicide applications in agriculture through resistance development is a widespread phenomenon. In particular, the grass Alopecurus myosuroides is an extremely problematic weed in cereal crops with the potential to manifest resistance in only a few generations. Target-site resistances (TSRs), with their strong phenotypic response, play an important role in this rapid adaptive response. Recently, using PacBio's long-read amplicon sequencing technology in hundreds of individuals, we were able to decipher the genomic context in which TSR mutations occur. However, sequencing individual amplicons are costly and time-consuming, thus impractical to implement for other resistance loci or applications. Alternatively, pool-based approaches overcome these limitations and provide reliable allele frequencies, although at the expense of not preserving haplotype information. In this proof-of-concept study, we sequenced with PacBio High Fidelity (HiFi) reads long-range amplicons (13.2 kb), encompassing the entire ACCase gene in pools of over 100 individuals, and resolved them into haplotypes using the clustering algorithm PacBio amplicon analysis (pbaa), a new application for pools in plants and other organisms. From these amplicon pools, we were able to recover most haplotypes from previously sequenced individuals of the same population. In addition, we analysed new pools from a Germany-wide collection of A. myosuroides populations and found that TSR mutations originating from soft sweeps of independent origin were common. Forward-in-time simulations indicate that TSR haplotypes will persist for decades even at relatively low frequencies and without selection, highlighting the importance of accurate measurement of TSR haplotype prevalence for weed management.     

Ligands induce conformational changes in the carboxyl-terminus of progesterone receptors which are detected by a site-directed antipeptide monoclonal antibody.

We have prepared a monoclonal antibody, C-262, to a synthetic peptide that contains the carboxy-terminal 14 amino acids from progesterone receptors (PR). This sequence is 100% conserved in all species of PRs that have been cloned to date, suggesting that this antibody will recognize all mammalian and avian PR. The C-262 antibody recognizes both native and denatured forms of the receptor. However, it does not recognize PR when they are bound to the hormone agonists progesterone or R5020. Surprisingly the antibody does recognize PR when they are bound to the steroid antagonist RU486. This suggests that progestin agonists induce a conformational change in the receptor that occludes the C-262 epitope in the carboxyl-terminus, whereas unliganded receptors and receptors bound with RU486 assume distinct conformations that leaves the C-terminal tail accessible to the C-262 antibody.     

Separation of phosphatidylinositols and other phospholipids by two-step one-dimensional thin-layer chromatography

A quick and efficient thin-layer chromatographic procedure is described for the separation of phosphatidylinositol-4,5-bisphosphate, phosphatidylinositol-4-monophosphate, phosphatidylinositol, phosphatidylcholine, phosphatidic acid, and phosphatidylethanolamine. The method involves development of the phospholipids successively in two different solvent systems but in the same direction. The method is simple, reproducible, and gives good resolution of the six different phospholipids tested. About 8-10 32P-labeled phospholipids isolated from rat hepatocytes were separated by this method; the six mentioned above were identified. Thus, the technique has potential application for both qualitative and quantitative analysis of phospholipid mixtures, such as the phosphoinositides, in cell or tissue extracts.