Adaptive diversity in genetic control of egg-laying behavior in Drosophila melanogaster

Summary

In the absence of insemination or of a suitable oviposition site, Drosophila melanogaster females react with egg retention patterns which differ as to the position in the genital tract at which the mechanism operates (ovarioles for initial retention; uterus for oviposition blocking) and to physiological basis. A study of the first laboratory generation of isofemale lines, founded by using three different samples of wild flies collected the same year from a natural population, showed a significant genetic variability in initial egg retention by virgin females and in the capacity for oviposition blocking by mated flies reacting to an unfavorable oviposition site. Comparison of isofemale lines showed that these two adaptive behavior patterns also differ in their genetic determination. They are controlled, and therefore can react, independently to selection pressures resulting from seasonal variation in the natural environment.     

Triterpene functional genomics in licorice for identification of CYP72A154 involved in the biosynthesis of glycyrrhizin

Glycyrrhizin, a triterpenoid saponin derived from the underground parts of Glycyrrhiza plants (licorice), has several pharmacological activities and is also used worldwide as a natural sweetener. The biosynthesis of glycyrrhizin involves the initial cyclization of 2,3-oxidosqualene to the triterpene skeleton β-amyrin, followed by a series of oxidative reactions at positions C-11 and C-30, and glycosyl transfers to the C-3 hydroxyl group. We previously reported the identification of a cytochrome P450 monooxygenase (P450) gene encoding β-amyrin 11-oxidase (CYP88D6) as the initial P450 gene in glycyrrhizin biosynthesis. In this study, a second relevant P450 (CYP72A154) was identified and shown to be responsible for C-30 oxidation in the glycyrrhizin pathway. CYP72A154 expressed in an engineered yeast strain that endogenously produces 11-oxo-β-amyrin (a possible biosynthetic intermediate between β-amyrin and glycyrrhizin) catalyzed three sequential oxidation steps at C-30 of 11-oxo-β-amyrin supplied in situ to produce glycyrrhetinic acid, a glycyrrhizin aglycone. Furthermore, CYP72A63 of Medicago truncatula, which has high sequence similarity to CYP72A154, was able to catalyze C-30 oxidation of β-amyrin. These results reveal a function of CYP72A subfamily proteins as triterpene-oxidizing enzymes and provide a genetic tool for engineering the production of glycyrrhizin.     

Current Outcomes of Laparoscopic Duodenal Switch

Background

Biliopancreatic diversion with duodenal switch (BPD-DS) has long been considered as the bariatric procedure with the highest peri-operative and long-term complication rate. However, modern peri-operative care, including laparoscopic and staged-approach, has significantly reduced the complication rate related to this procedure. The goal of this article is to provide an overview of the current outcomes of laparoscopic BPD-DS in a high volume centre.

Methods

All patients who had a laparoscopic BPD-DS with a hand-sewn anastomosis performed between 2011 and 2015 (N = 566) were reviewed. Data were obtained from our prospectively maintained electronic database and are reported as a Mean ± standard deviation.

Results

The mean age of the 566 patients was 41 ± 10 years, with 78 % women. Initial body mass index was 49 ± 6 kg/m². There was no 90-days mortality. Hospital stay was 4.5 ± 3 days. Major 30-days complications occurred in 3.0 % (n = 17) of the patients and minor complications in 2.5 % (N = 14). Excess weight loss was 81 ± 14 % at 12 m, 88 ± 13 % at 24 m, 83 ± 14 % at 36 months. Total body weight loss (kg) was 57 ± 13 kg at 12 months, 63 ± 14 kg at 24 months and 61 ± 17 kg at 36 months. Hemoglobin A1C (HbA1C) dropped from 6.1 ± 1 % to 4.7 ± 0.5 % (p < 0.005) and the percentage of patients with an HbA1C above 6 % decreased from 38 to 1.4 % (p < 0.005). Over 21 ± 12 months follow-up, readmission was required in 3.5 % and reoperation in 0.5 % of the patients.

Conclusion

The current short and medium-term complication rate of laparoscopic BPD-DS are similar to other mixed bariatric procedures with excellent metabolic outcomes.

     

Visualization of Mycobacterium avium in Crohn's tissue by oil-immersion microscopy

Studies seeking Mycobacterium avium subsp. paratuberculosis in Crohn's disease by PCR have generated inconsistent findings. As an alternative, microscopy offers a number of advantages, including direct visualization of organisms in tissue. Experimental infections have demonstrated that M. avium organisms can be seen by both acid-fast staining and species-specific in situ hybridization, but because they are smaller than M. tuberculosis, oil-immersion microscopy (×1000 magnification) is needed. We performed a blinded search for M. avium in paraffin-embedded surgical resections from Crohn's and control subjects at two centres. Specimens were coded and subjected to acid-fast staining and ribosomal RNA in situ hybridization for M. avium rRNA. Agreement between these two methods was good (42/52 patients, κ = 0.60) and similar results were observed for patients from two centers. Together, both methods provided positive results in 10 of 17 Crohn's subjects (59%, 95% CI: 36–78), contrasting with only 5 of 35 control subjects (Odds ratio for Crohn's vs. controls = 8.6, p = 0.002). M. avium organisms had an intracellular localization within inflammatory lesions, but were often observed as lone organisms outside of granulomas. Using two assays in two settings, presence of M. avium organisms was strongly associated with Crohn's disease.     

Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders

Theories of autism spectrum disorders (ASD) have focused on altered perceptual integration of sensory features as a possible core deficit. Yet, there is little understanding of the neuronal processing of elementary sensory features in ASD. For typically developed individuals, we previously established a direct link between frequency-specific neural activity and the intensity of a specific sensory feature: Gamma-band activity in the visual cortex increased approximately linearly with the strength of visual motion. Using magnetoencephalography (MEG), we investigated whether in individuals with ASD neural activity reflect the coherence, and thus intensity, of visual motion in a similar fashion. Thirteen adult participants with ASD and 14 control participants performed a motion direction discrimination task with increasing levels of motion coherence. A polynomial regression analysis revealed that gamma-band power increased significantly stronger with motion coherence in ASD compared to controls, suggesting excessive visual activation with increasing stimulus intensity originating from motion-responsive visual areas V3, V6 and hMT/V5. Enhanced neural responses with increasing stimulus intensity suggest an enhanced response gain in ASD. Response gain is controlled by excitatory-inhibitory interactions, which also drive high-frequency oscillations in the gamma-band. Thus, our data suggest that a disturbed excitatory-inhibitory balance underlies enhanced neural responses to coherent motion in ASD.     

Formation of 2-hydroxy-4-methylpentanoic acid from l-leucine by Clostridium butyricum

Abstract Five Clostridium butyricum strains of different origin were grown in trypticase-yeast extract-hemin medium with or without d-glucose (TGYH or TYH medium, respectively) and in a synthetic basal medium with d-glucose (BMG medium). 2-Hydroxy-4-methylpentanoic acid was detected by gas chromatography-mass spectrometry (GC-MS) for the five strains whether grown in TGYH or TYH medium (270 or 170 μM, respectively). In BMG medium supplemented with l-leucine (10 mM), the concentration of this metabolite was strongly increased (2.8 mM versus 10 μM in the control). After culture in TGYH or TYH medium supplemented with l-( methyl -²H₃)leucine, 2-hydroxy-4-([²H₃]methyl)pentanoic acid was detected by GC-MS. This observation demonstrates that C. butyricum is able to convert l-leucine into the corresponding 2-hydroxy acid and opens a new aspect in the study of C. butyricum metabolism.