Solubilization and partial purification of steroid sulfatase from rat liver: characterization of estrone sulfatase.

Steroid sulfatase, a membrane-bound enzyme present in many mammalian tissues, was extracted from rat liver microsomes by treatment with Miranol H2M, a zwitterion detergent, and sonication. It has been purified approximately 33-fold. All steps of the purification, which included salt and solvent fractionation, hydroxylapatite treatment, ion-exchange chromatography, and gel filtration were performed in the presence of Miranol H2M, most of which was removed from the final preparation by gel filtration. The final preparation did not contain any detectable NADPH-cytochrome c reductase or glucose-6-phosphate phophatase activities. According to the elution volume on a Sephadex G-200 column, steroid sulfatase has a molecular weight of approximately 130,000. Polyacrylamide-gel electrophoresis in the presence of Miranol H2M revealed one major protein band which was enzymatically active. Purified steroid sulfatase hydrolyzes all the sulfate esters of estrone, dehydroepiandrosterone, pregnenolone, testosterone, and cholesterol as well as p-nitrophenyl sulfate, the substrate for arylsulfatase C, during the purification. However, estrone sulfatase and arylsulfatase C activities were enriched more than the others. Analysis of kinetic data and the effects of different buffers and of Miranol H2M also suggested that estrone sulfatase and arylsulfatase C are identical but that they are distinct from the other sulfatases. Competitive inhibition studies suggest that estrone sulfatase also catalyzes the hydrolysis of the sulfate esters of other estrogens.     

Allencotyla pricei sp. n. (Microcotyloidea: Heteraxinidae) from the gills of the pile surfperch, Damalichthys vacca (Girard), in southern California

Allencotyla pricei sp. n. (Monogenea: Heteraxinidae) from the gills of pile surfperch, Damalichthys vacca (Girard), from Redondo Beach, California is described. This species is distinguished primarily by the prebifurcal position of the genital atrium and vagina, and by possessing an elongate esophagus. The systematic arrangement of microcotyloid forms characterized by an asymmetric haptor is discussed.     

Ant community composition and functional traits in new grassland strips within agricultural landscapes

1. Ongoing intensification and fragmentation of European agricultural landscapes dramatically reduce biodiversity and associated functions. Enhancing perennial noncrop areas holds great potential to support ecosystem services such as ant‐mediated pest control.
2. To study the potential of newly established grassland strips to enhance ant diversity and associated functions, we used hand collection data and predation experiments to investigate differences in (a) ant community composition and (b) biocontrol‐related functional traits, and (c) natural pest control across habitats in cereal fields, old grasslands, and new grassland transects of three years of age.
3. Ant species diversity was similar between new and old grasslands, but significantly higher in new grasslands than in surrounding cereal fields. Contrary, ant community composition of new grasslands was more similar to cereal fields and distinct from the species pool of old grasslands. The functional trait space covered by the ant communities showed the same distribution between old and new grasslands. Pest control did not differ significantly between habitat types and therefore could not be linked to the prevalence of functional ant traits related to biocontrol services in new grasslands.
4. Our findings not only show trends of convergence between old and new grasslands, but also indicate that enhancing ant diversity through new grasslands takes longer than three years to provide comparable biodiversity and functionality.
5. Synthesis and applications: Newly established grasslands can increase ant species richness and abundance and provide a consistent amount of biocontrol services in agroecosystems. However, three years after their establishment, new grasslands were still dominated by common agrobiont ant species and lacked habitat specialists present in old grasslands, which require a constant supply of food resources and long colony establishment times. New grasslands represent a promising measure for enhancing agricultural landscapes but must be preserved in the longer term to promote biodiversity and resilience of associated ecosystem services.

     

Guanine nucleotides regulate the effect of substance P on striatal adenylate cyclase of the rat.

Substance P was incubated in an adenylate cyclase assay of a particulate fraction of caudate-putamen tissue of the rat in order to examine the effect of the peptide on D-1 receptor coupled adenylate cyclase in vitro. Substance P did not influence basal adenylate cyclase activity or the stimulation of the enzyme by dopamine. No influence of substance P was seen on the effects of calcium and magnesium chloride as a cofactor of adenylate cyclase. Also the inhibition of adenylate cyclase activity by the dopamine antagonist fluphenazine was not influenced by substance P. However, substance P was able to enhance cyclic AMP formation in the presence of guanosine-imidodiphosphate (Gpp(NH)p), whereas the stimulatory effect of guanosine-triphosphate (GTP) was inhibited by substance P. In our study we suggest that substance P interacts with the guanine nucleotide regulatory subunit without directly affecting D-1 dopamine receptors in the caudate-putamen of the rat.     

Cytochrome P450 CYP89A9 Is Involved in the Formation of Major Chlorophyll Catabolites during Leaf Senescence in Arabidopsis

Nonfluorescent chlorophyll catabolites (NCCs) were described as products of chlorophyll breakdown in Arabidopsis thaliana. NCCs are formyloxobilin-type catabolites derived from chlorophyll by oxygenolytic opening of the chlorin macrocycle. These linear tetrapyrroles are generated from their fluorescent chlorophyll catabolite (FCC) precursors by a nonenzymatic isomerization inside the vacuole of senescing cells. Here, we identified a group of distinct dioxobilin-type chlorophyll catabolites (DCCs) as the major breakdown products in wild-type Arabidopsis, representing more than 90% of the chlorophyll of green leaves. The molecular constitution of the most abundant nonfluorescent DCC (NDCC), At-NDCC-1, was determined. We further identified cytochrome P450 monooxygenase CYP89A9 as being responsible for NDCC accumulation in wild-type Arabidopsis; cyp89a9 mutants that are deficient in CYP89A9 function were devoid of NDCCs but accumulated proportionally higher amounts of NCCs. CYP89A9 localized outside the chloroplasts, implying that FCCs occurring in the cytosol might be its natural substrate. Using recombinant CYP89A9, we confirm FCC specificity and show that fluorescent DCCs are the products of the CYP89A9 reaction. Fluorescent DCCs, formed by this enzyme, isomerize to the respective NDCCs in weakly acidic medium, as found in vacuoles. We conclude that CYP89A9 is involved in the formation of dioxobilin-type catabolites of chlorophyll in Arabidopsis.     

Neural networks in intestinal immunoregulation

Key physiological functions of the intestine are governed by nerves and neurotransmitters. This complex control relies on two neuronal systems: an extrinsic innervation supplied by the two branches of the autonomic nervous system and an intrinsic innervation provided by the enteric nervous system. As a result of constant exposure to commensal and pathogenic microflora, the intestine developed a tightly regulated immune system. In this review, we cover the current knowledge on the interactions between the gut innervation and the intestinal immune system. The relations between extrinsic and intrinsic neuronal inputs are highlighted with regards to the intestinal immune response. Moreover, we discuss the latest findings on mechanisms underlying inflammatory neural reflexes and examine their relevance in the context of the intestinal inflammation. Finally, we discuss some of the recent data on the identification of the gut microbiota as an emerging player influencing the brain function.     

Soothing the Threatened Brain: Leveraging Contact Comfort with Emotionally Focused Therapy

Social relationships are tightly linked to health and well-being. Recent work suggests that social relationships can even serve vital emotion regulation functions by minimizing threat-related neural activity. But relationship distress remains a significant public health problem in North America and elsewhere. A promising approach to helping couples both resolve relationship distress and nurture effective interpersonal functioning is Emotionally Focused Therapy for couples (EFT), a manualized, empirically supported therapy that is strongly focused on repairing adult attachment bonds. We sought to examine a neural index of social emotion regulation as a potential mediator of the effects of EFT. Specifically, we examined the effectiveness of EFT for modifying the social regulation of neural threat responding using an fMRI-based handholding procedure. Results suggest that EFT altered the brain''s representation of threat cues in the presence of a romantic partner. EFT-related changes during stranger handholding were also observed, but stranger effects were dependent upon self-reported relationship quality. EFT also appeared to increase threat-related brain activity in regions associated with self-regulation during the no-handholding condition. These findings provide a critical window into the regulatory mechanisms of close relationships in general and EFT in particular.