פרסומים

The accumulation of geosmin and 2-methylisoborneol in culture water and fish is a common problem encountered in recirculating aquaculture systems (RAS). In these systems, like in other aquaculture systems, abatement of this problem is usually conducted by purging the fish with clean water prior to their marketing. In indoor RAS, mainly heterotrophic prokaryotes underlie the production of geosmin and MIB. While production of these off flavor compounds has been linked with the organic-rich parts of these systems, no further information on factors that promote the growth of the geosmin and MIB-producing microorganisms under these conditions is currently available. Thus far, geosmin and MIB removal from RAS has mainly been conducted by ozonation, albeit with limited success. Biodegradation of geosmin and MIB might serve as an additional method for removal of these compounds from RAS. Geosmin and MIB degradation has been detected in the latter systems, yet factors which promote the activity of geosmin and MIB degraders in these systems remain largely unknown. In the present review, the current knowledge on geosmin and MIB production and removal in RAS is presented. Emphasis is placed on the biodegradation of these off-flavor compounds, a process which has received little attention thus far.

Floral pollen is a major source of honey bee nutrition that provides them with micro- and macro-nutrients, including proteins, fatty acids, vitamins, and minerals. Different pollens vary in composition, including in the essential fatty acids, alpha-linolenic acid (omega-3) and linoleic acid (omega-6). Monocultures, prevalent in modern agriculture, may expose honey bee colonies to unbalanced omega-6:3 diets. The importance of omega-3 in the diet for adequate learning and cognitive function, with a focus on suitable omega-6:3 ratio, is well documented in mammals. We have recently shown, for the first time in invertebrates, the importance of omega-3 in diets for associative learning ability in honey bees. In the current work, we examine the effect of the absolute amount of omega-3 in diet compared to the omega-6:3 ratio on honey bee associative learning. We fed newly emerged bees for 1 week on different artificial diets, which had lipid concentration of 1, 2, 4, or 8%, with omega-6:3 ratios of 0.3, 1, or 5, respectively. We then tested the bees in a proboscis-extension response olfactory conditioning assay. We found that both omega-6:3 ratio and total lipid concentration affected learning. The most detrimental diet for learning was that with a high omega-6:3 ratio of 5, regardless of the absolute amount of omega-3 in the diet. Bees fed an omega-6:3 ratio of 1, with 4% total lipid concentration achieved the best performance. Our results with honey bees are consistent with those found in mammals. Best cognitive performance is achieved by a diet that is sufficiently rich in essential fatty acids, but as long as the omega-6:3 ratio is not high.

We demonstrate an approach for on-chip beam positioning with a position accuracy of up to 100 nm. This approach is based on tracking the resonance of two adjacent microring resonators that are implemented on a silicon on insulator chip. We demonstrate the functionality of our approach by illuminating the chip through a Near Field Scanning Optical Microscope tip and monitoring the shift of the microring resonances due to the thermo-optic effect. We also discuss the contribution of different effects such as free carrier absorption and dispersion to the resonance shift.

First Published in 2018. Routledge is an imprint of Taylor & Francis, an Informa company. © 1990 by CRC Press, LLC.

Background: Iatrogenic ureteral injury is an increasing concern in the laparoscopic era, affecting both patient morbidity and costs. Current techniques enabling intraoperative ureteral identification require invasive procedures or radiations. Our aim was to develop a real-time, non-invasive, radiation-free method to visualize ureters, based on near-infrared (NIR) imaging. For this purpose, we interfered with the biliary excretion pathway of the indocyanine green (ICG) fluorophore by loading it into liposomes, enabling renal excretion. In this work, we studied various parameters influencing ureteral imaging. Methods: Fluorescence intensity (FI) of various liposomal ICG sizes and doses were characterized in vitro and subsequently tested in vivo in mice and pigs. Quantification was performed by measuring FI in multiple points and applying the ureteral/retroperitoneum ratio (U/R). Results: The optimal liposomal ICG loading dose was 20%, for the different liposomes' sizes tested (30, 60, 100 nm). Higher concentration of ICG decreased FI. In vivo, the optimal liposome size for ureteral imaging was 60 nm, which yielded a U/R of 5.2 $\pm$ 1.7 (p < 0.001 vs. free ICG). The optimal ICG dose was 8 mg/kg (U/R = 2.1 $\pm$ 0.4, p < 0.05 vs. 4 mg/kg). Only urine after liposomal ICG injection had a measurable FI, and not after free ICG injection. Using a NIR-optimized laparoscopic camera, ureters could be effectively imaged in pigs, from 10 min after injection and persisting for at least 90 min. Ureteral peristaltic waves could be clearly identified only after liposomal ICG injection. Conclusions: Optimization of liposomal ICG allowed to visualize enhanced ureters in animal models and seems a promising fluorophore engineering, which calls for further developments.

BACKGROUND AND AIM: Non-alcoholic fatty liver disease (NAFLD) is associated with all features of the metabolic syndrome. Deposition of excess triglycerides in liver cells, a hallmark of NAFLD, is associated with loss of insulin sensitivity. Ostreolysin (Oly) is a 15-kDa fungal protein known to interact with cholesterol-enriched raft-like membrane domains. We aim to test whether a recombinant version of Oly (rOly) can induce functional changes in vitro in adipocytes or in vivo in mice fed a high-fat diet (HFD). METHODS: White preadipocyte 3T3-L1 cells or mouse primary adipocytes treated with rOly. Male C57BL/6 mice were fed a control or HFD and treated with saline or with rOly (1 mg/kg BW) every other day for 4 weeks. RESULTS: White preadipocyte 3T3-L1 cells or mouse primary adipocytes treated with rOly acquire a browning phenotype through activation of 5' adenosine monophosphate-activated protein kinase and downregulation of tumor necrosis factor alpha-mediated activation of IkappaB kinase epsilon and TANK-binding kinase 1. HFD-fed mice treated with rOly showed a 10% reduction in BW and improved glucose tolerance, which paralleled improved expression of liver and adipose functionality, metabolism, and inflammation status, mimicking the in vitro findings. CONCLUSION: This study provides first evidence of rOly's prevention of HFD-induced NAFLD by stimulating liver and adipose muscle tissue functionality and oxidative potential, improving glucose tolerance, and ameliorating the metabolic profile of diet-induced obese mice.