Effect of morphine and abstinence syndrome on [3H]bromoxidine binding to α2-adrenoreceptors in rat brain

At 4 days after the implantation of two subcutaneous 75 mg morphine pellets in the back skin, rats were morphine-dependent. In the three layers studied in the occipital cortex we found that the values of the ₂-adrenergic agonist [³H]bromoxidine binding increased with respect to animals implanted with placebo pellets. Typical behavioral and physiological symptoms of the abstinence syndrome appeared 30 minutes after administration of naloxone, [³H]bromoxidine binding values being similar to those obtained in animals implanted with placebo pellets. The pattern of response of the [³H]bromoxidine binding was similar in the hippocampus and the superficial gray layer of the superior colliculus of the mesencephalon, but the differences were not statistically significant in these areas. This paper concludes that exist brain regional differences in the ₂-adrenoreceptors response under morphine-treatment and possibly under naloxone-induced morphine abstinence syndrome.     

Genetics and biochemistry of phenol degradation byPseudomonas sp. CF600

Pseudomonas sp. strain CF600 is an efficient degrader of phenol and methylsubstituted phenols. These compounds are degraded by the set of enzymes encoded by the plasmid locateddmpoperon. The sequences of all the fifteen structural genes required to encode the nine enzymes of the catabolic pathway have been determined and the corresponding proteins have been purified. In this review the interplay between the genetic analysis and biochemical characterisation of the catabolic pathway is emphasised. The first step in the pathway, the conversion of phenol to catechol, is catalysed by a novel multicomponent phenol hydroxylase. Here we summarise similarities of this enzyme with other multicomponent oxygenases, particularly methane monooxygenase (EC 1.14.13.25). The other enzymes encoded by the operon are those of the well-knownmeta-cleavage pathway for catechol, and include the recently discoveredmeta-pathway enzyme aldehyde dehydrogenase (acylating) (EC 1.2.1.10). The known properties of thesemeta-pathway enzymes, and isofunctional enzymes from other aromatic degraders, are summarised. Analysis of the sequences of the pathway proteins, many of which are unique to themeta-pathway, suggests new approaches to the study of these generally little-characterised enzymes. Furthermore, biochemical studies of some of these enzymes suggest that physical associations betweenmeta-pathway enzymes play an important role. In addition to the pathway enzymes, the specific regulator of phenol catabolism, DmpR, and its relationship to the XylR regulator of toluene and xylene catabolism is discussed.     

Aluminum alters calcium transport in plasma membrane and endoplasmic reticulum from rat brain

Calcium is actively transported into intracellular organelles and out of the cytoplasm by Ca²⁺/Mg²⁺-ATPases located in the endoplasmic reticulum and plasma membranes. We studied the effects of aluminum on calcium transport in the adult rat brain. We examined ⁴⁵Ca-uptake in microsomes and Ca²⁺-ATPase activity in microsomes and synaptosomes isolated from the frontal cortex and cerebellum of adult male Long-Evans rats. ATP-dependent⁴⁵Ca-uptake was similar in microsomes from both brain regions. The addition of 50-800 μM AICI₃ resulted in a concentration-dependent inhibition of ⁴⁵Ca-uptake. Mg²⁺-dependent Ca²⁺-ATPase activity was significantly lower in synaptosomes compared to microsomes in both frontal cortex and cerebellum. In contrast to the uptake studies, AICI³ stimulated Mg²⁺-dependent Ca²⁺-ATPase activity in both microsomes and synaptosomes from both brain regions. To determine the relationship between aluminum and Mg²⁺, we measured ATPase activity in the presence of increasing concentrations of Mg²⁺ or AICI³. Maximal ATPase activity was obtained between 3 and 6 mM Mg²⁺. When we substituted AICI³ for Mg²⁺, ATPase activity was also stimulated in a concentration-dependent manner, but to a greater extent than with Mg²⁺. One interpretation of these data is that aluminum acts at multiple sites to displace both Mg²⁺ and Ca²⁺, increasing the activity of the Ca²⁺-ATPase, but disrupting transport of calcium.     

Comparison between the complete mtDNA sequences of the blue and the fin whale,two species that can hybridize in nature

The sequence of the mitochondrial DNA (mtDNA) molecule of the blue whale (Balaenoptera musculus) was determined. The molecule is 16,402 by long and its organization conforms with that of other eutherian mammals. The molecule was compared with the mtDNA of the congeneric fin whale (B. physalus). It was recently documented that the two species can hybridize and that male offspring are infertile whereas female offspring may be fertile. The present comparison made it possible to determine the degree of mtDNA difference that occurs between two species that are not completely separated by hybridization incompatibility. The difference between the complete mtDNA sequences was 7.4%. Lengths of peptide coding genes were the same in both species. Except for a small portion of the control region, disruption in alignment was usually limited to insertion/deletion of a single nucleotide. Nucleotide differences between peptide coding genes ranged from 7.1 to 10.5%, and difference at the inferred amino acid level was 0.0–7.9%. In the rRNA genes the mean transition difference was 3.8%. This figure is similar in degree to the difference (3.4%) between the 12S rRNA gene of humans and the chimpanzee. The mtDNA differences between the two whale species, involving both peptide coding and rRNA genes, suggest an evolutionary separation of 5 million years. Although hybridization between more distantly related mammalian species may not be excluded, it is probable that the blue and fin whales are nearly as different in their mtDNA sequences as hybridizing mammal species may be. Correspondence to: Ú. Árnason     

Three-dimensional species distribution modelling reveals the realized spatial niche for coral recruitment on contemporary Caribbean reefs

The three-dimensional structure of habitats is a critical component of species' niches driving coexistence in species-rich ecosystems. However, its influence on structuring and partitioning recruitment niches has not been widely addressed. We developed a new method to combine species distribution modelling and structure from motion, and characterized three-dimensional recruitment niches of two ecosystem engineers on Caribbean coral reefs, scleractinian corals and gorgonians. Fine-scale roughness was the most important predictor of suitable habitat for both taxa, and their niches largely overlapped, primarily due to scleractinians' broader niche breadth. Crevices and holes at mm scales on calcareous rock with low coral cover were more suitable for octocorals than for scleractinian recruits, suggesting that the decline in scleractinian corals is facilitating the recruitment of octocorals on contemporary Caribbean reefs. However, the relative abundances of the taxa were independent of the amount of suitable habitat on the reef, emphasizing that niche processes alone do not predict recruitment rates.     

Towards an ethical and legal framework in archeogenomics: A local case in the Atlantic coast of central Patagonia

Ethical discussions around ancient DNA (aDNA) research predate the technological breakthroughs that led to the accelerated generation of ancient genomic data, revealing a long-due need to address these aspects in the field. Given the diverse conflicts that genomics has raised towards the communities associated with the Non-living Human Ancestors under study, it has been suggested that the ethical and legal implications of genetically studying present-day and ancient human populations should be considered case-by-case. Nevertheless, the discussions have focused on US and European perspectives. To contribute from a local and Latin American position to the problem, we present the history of consensus and disagreement of the relationships between scientists and Indigenous communities of the Atlantic coast of the central Argentinian Patagonia. We describe how these relationships resulted in the approval of a groundbreaking provincial law that acknowledges the Indigenous community's right to be involved in decision-making concerning their Ancestors. In addition, we emphasize how these established relationships allowed the development of aDNA studies. With this background, we address the main ethical concerns of genomic studies of Ancestors identified in the reference literature and commit to applying some of the recommendations suggested in those ethical guidelines. Then, we reflect on possible negative consequences of ongoing research and propose some suggestions based on personal experiences that will contribute to moving the ethical field towards a more contextualized science with a local perspective.     

Comparison of European and US biological indicators for ethylene oxide sterilization

Summary Biological indicators (BIs) are used to monitor ethylene oxide (EO) gas sterilization processes for medical devices. Several European and United States BIs for EO sterilization were evaluated for resistance according to both United States Pharmacopeia (USP) XXI and United Kingdom's (UK) tests for D-values. US BIs areB. subtilis var. niger spores on paper strips or disc carriers while European BIs use aluminum strips, quartz sand, or cotton yarn. Numerous BIs per run and runs per lot, as well as 2–3 different lots of BIs from each manufacturer, were examined. Both British and US BIs met their respective label claims for rates of inactivation when tested against British and USP EO test parameters, respectively. However, Danish BIs, on cotton yarn or quartz sand, were not inactivated following USP specifications during the exposure dwell times tested (600 mg L^–1 EO, 54°C, 60% RH, 0–110 min). The Danish BIs will require further testing in order for us to determine if theirB. subtilis spores are unusually resistant to EO or if the spore carrier substrates protect the spores from the sterilizing gas. In conclusion, the British and American BIs for EO sterilization are equivalent in resistance despite differences in carrier substrate, recovery conditions, calculation methods for D-values, and the labeled sterilization conditions for use.     

Pattern-based clustering of daily weigh-in trajectories using dynamic time warping

“Smart”-scales are a new tool for frequent monitoring of weight change as well as weigh-in behavior. These scales give researchers the opportunity to discover patterns in the frequency that individuals weigh themselves over time, and how these patterns are associated with overall weight loss. Our motivating data come from an 18-month behavioral weight loss study of 55 adults classified as overweight or obese who were instructed to weigh themselves daily. Adherence to daily weigh-in routines produces a binary times series for each subject, indicating whether a participant weighed in on a given day. To characterize weigh-in by time-invariant patterns rather than overall adherence, we propose using hierarchical clustering with dynamic time warping (DTW). We perform an extensive simulation study to evaluate the performance of DTW compared to Euclidean and Jaccard distances to recover underlying patterns in adherence time series. In addition, we compare cluster performance using cluster validation indices (CVIs) under the single, average, complete, and Ward linkages and evaluate how internal and external CVIs compare for clustering binary time series. We apply conclusions from the simulation to cluster our real data and summarize observed weigh-in patterns. Our analysis finds that the adherence trajectory pattern is significantly associated with weight loss.