The Ratification of Inadequate Surrogate Motherhood Agreements and the Best Interest of the Child

South Africa has developed domestic legislation governing all surrogacy matters within the country. These provisions are contained in Chapter 19 of the Children's Act 38 of 2005.In Ex parte MS; In re: Confirmation of Surrogate Motherhood Agreement 2014 2 All SA 312 (GNP), the commissioning parents did not adhere to the requirement provided by Chapter 19. The parties to the (initially informal) surrogacy agreement authorised the artificial fertilisation of the surrogate mother prior to the confirmation of the surrogate motherhood agreement by the court. In considering the best interest of the resultant child, the High Court decided to ratify the inadequate surrogate motherhood agreement.This discussion aims to establish whether the court's judgement in Ex parte MS; In re: Confirmation of Surrogate Motherhood Agreement was in accordance with the provisions of current legislation and case law. It furthermore aims to answer two primary questions: firstly, whether adjudicators should make use of the best interest of the child when ratifying inadequate surrogate motherhood agreements; and secondly, in what manner the court should go about implementing the best interest of the child when validating inadequate surrogate motherhood agreements.It is submitted that courts should refrain from applying the best interest of the child as a constitutional right in inadequate surrogacy matters where the child is yet to be born alive, in accordance with the Digesta Texts. Parties to the invalid agreement should rather be instructed to make use of a section 22 parental responsibilities and rights agreement, a section 28 termination agreement, or adoption as provided for by chapter 15 of the Children's Act

The Ratification of Inadequate Surrogate Motherhood Agreements and the Best Interest of the Child

South Africa has developed domestic legislation governing all surrogacy matters within the country. These provisions are contained in Chapter 19 of the Children's Act 38 of 2005. In Ex parte MS; In re: Confirmation of Surrogate Motherhood Agreement 2014 2 All SA 312 (GNP), the commissioning parents did not adhere to the requirement provided by Chapter 19. The parties to the (initially informal) surrogacy agreement authorised the artificial fertilisation of the surrogate mother prior to the confirmation of the surrogate motherhood agreement by the court. In considering the best interest of the resultant child, the High Court decided to ratify the inadequate surrogate motherhood agreement. This discussion aims to establish whether the court's judgement in Ex parte MS; In re: Confirmation of Surrogate Motherhood Agreement 2014 2 All SA 312 (GNP) was in accordance with the provisions of current legislation and case law. It furthermore aims to answer two primary questions: firstly, whether adjudicators should make use of the best interest of the child when ratifying inadequate surrogate motherhood agreements; and secondly, in what manner the court should go about implementing the best interest of the child when validating inadequate surrogate motherhood agreements. It is submitted that courts should refrain from applying the best interest of the child as a constitutional right in inadequate surrogacy matters where the child is yet to be born alive, in accordance with the Digesta Texts. Parties to the invalid agreement should rather be instructed to make use of a section 22 parental responsibilities and rights agreement, a section 28 termination agreement, or adoption as provided for by chapter 15 of the Children's Act.    &nbsp

Astrocytes regulate GLP-1 receptor-mediated effects on energy balance

© 2016 the authors. Astrocytes are well established modulators of extracellular glutamate, but their direct influence on energy balance-relevant behaviors is largely understudied. As the anorectic effects of glucagon-like peptide-1 receptor (GLP-1R) agonists are partly mediated by central modulation of glutamatergic signaling, we tested the hypothesis that astrocytic GLP-1R signaling regulates energy balance in rats. Central or peripheral administration of a fluorophore-labeled GLP-1R agonist, exendin-4, localizes within astrocytes and neurons in the nucleus tractus solitarius (NTS), a hindbrain nucleus critical for energy balance control. This effect is mediated by GLP-1R, as the uptake of systemically administered fluorophore-tagged exendin-4 was blocked by central pretreatment with the competitive GLP-1R antagonist exendin-(9–39). Ex vivo analyses show prolonged exendin-4-induced activation (live cell calcium signaling) of NTS astrocytes and neurons; these effects are also attenuated by exendin-(9–39), indicating mediation by the GLP-1R. In vitro analyses show that the application of GLP-1R agonists increases cAMP levels in astrocytes. Immunohistochemical analyses reveal that endogenous GLP-1 axons form close synaptic apposition with NTS astrocytes. Finally, pharmacological inhibition of NTS astrocytes attenuates the anorectic and body weight-suppressive effects of intra-NTS GLP-1R activation. Collectively, data demonstrate a role for NTS astrocytic GLP-1R signaling in energy balance control

Characterization of the 6-methyl isoxanthopterin (6-MI) base analog dimer, a spectroscopic probe for monitoring guanine base conformations at specific sites in nucleic acids

We here characterize local conformations of site-specifically placed pairs of guanine (G) residues in RNA and DNA, using 6-methyl isoxanthopterin (6-MI) as a conformational probe. 6-MI is a base analog of G and spectroscopic signals obtained from pairs of adjacent 6-MI residues reflect base–base interactions that are sensitive to the sequence context, local DNA conformation and solvent environment of the probe bases. CD signals show strong exciton coupling between stacked 6-MI bases in double-stranded (ds) DNA; this coupling is reduced in single-stranded (ss) DNA sequences. Solvent interactions reduce the fluorescence of the dimer probe more efficiently in ssDNA than dsDNA, while self-quenching between 6-MI bases is enhanced in dsDNA. 6-MI dimer probes closely resemble adjacent GG residues, in that these probes have minimal effects on the stability of dsDNA and on interactions with solvent additive betaine. They also serve as effective template bases, although further polymerase-dependent extension of DNA primers past 6-MI template bases is significantly inhibited. These probes are also used to monitor DNA ‘breathing’ at model replication forks. The 6-MI dimer probe can serve in many contexts as a useful tool to investigate GG conformations at specific sites within the nucleic acid frameworks of functioning macromolecular machines in solution

DNA models of trinucleotide frameshift deletions: the formation of loops and bulges at the primer–template junction

Although mechanisms of single-nucleotide residue deletion have been investigated, processes involved in the loss of longer nucleotide sequences during DNA replication are poorly understood. Previous reports have shown that in vitro replication of a 3′-TGC TGC template sequence can result in the deletion of one 3′-TGC. We have used low-energy circular dichroism (CD) and fluorescence spectroscopy to investigate the conformations and stabilities of DNA models of the replication intermediates that may be implicated in this frameshift. Pyrrolocytosine or 2-aminopurine residues, site-specifically substituted for cytosine or adenine in the vicinity of extruded base sequences, were used as spectroscopic probes to examine local DNA conformations. An equilibrium mixture of four hybridization conformations was observed when template bases looped-out as a bulge, i.e. a structure flanked on both sides by duplex DNA. In contrast, a single-loop structure with an unusual unstacked DNA conformation at its downstream edge was observed when the extruded bases were positioned at the primer–template junction, showing that misalignments can be modified by neighboring DNA secondary structure. These results must be taken into account in considering the genetic and biochemical mechanisms of frameshift mutagenesis in polymerase-driven DNA replication

Screened non-bonded interactions in native proteins manipulate optimal paths for robust residue communication

A protein structure is represented as a network of residues whereby edges are determined by intra-molecular contacts. We introduce inhomogeneity into these networks by assigning each edge a weight that is determined by amino-acid pair potentials. Two methodologies are utilized to calculate the average path lengths (APLs) between pairs: To minimize (i) the maximum weight in the strong APL, and (ii) the total weight in the weak APL. We systematically screen edges that have higher than a cutoff potential and calculate the shortest APLs in these reduced networks, while keeping chain connectivity. Therefore, perturbations introduced at a selected region of the residue network propagate to remote regions only along the non-screened edges that retain their ability to disseminate the perturbation. The shortest APLs computed from the reduced homogeneous networks with only the strongest few non-bonded pairs closely reproduce the strong APLs from the weighted networks. The rate of change in the APL in the reduced residue network as compared to its randomly connected counterpart remains constant until a lower bound. Upon further link removal, this property shows an abrupt increase, towards a random coil behavior. Under different perturbation scenarios, diverse optimal paths emerge for robust residue communication.Comment: 21 pages with 6 figure

Modulation of a protein free-energy landscape by circular permutation

Circular permutations usually retain the native structure and function of a protein while inevitably perturb its folding dynamics. By using simulations with a structure-based model and a rigorous methodology to determine free-energy surfaces from trajectories we evaluate the effect of a circular permutation on the free-energy landscape of the protein T4 lysozyme. We observe changes which, while subtle, largely affect the cooperativity between the two subdomains. Such a change in cooperativity has been previously experimentally observed and recently also characterized using single molecule optical tweezers and the Crooks relation. The free-energy landscapes show that both the wild type and circular permutant have an on-pathway intermediate, previously experimentally characterized, where one of the subdomains is completely formed. The landscapes, however, differ in the position of the rate-limiting step for folding, which occurs before the intermediate in the wild-type and after in the circular permutant. This shift of transition state explains the observed change in the cooperativity. The underlying free-energy landscape thus provides a microscopic description of the folding dynamics and the connection between circular permutation and the loss of cooperativity experimentally observed

What Is a Microsatellite: A Computational and Experimental Definition Based upon Repeat Mutational Behavior at A/T and GT/AC Repeats

Microsatellites are abundant in eukaryotic genomes and have high rates of strand slippage-induced repeat number alterations. They are popular genetic markers, and their mutations are associated with numerous neurological diseases. However, the minimal number of repeats required to constitute a microsatellite has been debated, and a definition of a microsatellite that considers its mutational behavior has been lacking. To define a microsatellite, we investigated slippage dynamics for a range of repeat sizes, utilizing two approaches. Computationally, we assessed length polymorphism at repeat loci in ten ENCODE regions resequenced in four human populations, assuming that the occurrence of polymorphism reflects strand slippage rates. Experimentally, we determined the in vitro DNA polymerase-mediated strand slippage error rates as a function of repeat number. In both approaches, we compared strand slippage rates at tandem repeats with the background slippage rates. We observed two distinct modes of mutational behavior. At small repeat numbers, slippage rates were low and indistinguishable from background measurements. A marked transition in mutability was observed as the repeat array lengthened, such that slippage rates at large repeat numbers were significantly higher than the background rates. For both mononucleotide and dinucleotide microsatellites studied, the transition length corresponded to a similar number of nucleotides (approximately 10). Thus, microsatellite threshold is determined not by the presence/absence of strand slippage at repeats but by an abrupt alteration in slippage rates relative to background. These findings have implications for understanding microsatellite mutagenesis, standardization of genome-wide microsatellite analyses, and predicting polymorphism levels of individual microsatellite loci