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Head of Institute: Prof. Oren Tirosh

Administrative manager: Ms. Yael Fruchter

Office Address:
Institute of Biochemistry, Food Science and Nutrition,
Robert H. Smith Faculty of Agriculture, Food and Environment,
The Hebrew University of Jerusalem, 
P.O.Box 12, Rehovot 7610001, ISRAEL

Tel: +972 - (0)8-9489385
Fax: +972 - (0)8-9363208
Email Address: yaelf@savion.huji.ac.il

Publications

2021
Bissoyi, A. ; Braslavsky, I. Adherent cell thawing by infrared radiation. 2021. Publisher's VersionAbstract
Cryopreservation of adherent cells is crucial for commercial cell therapy technology, including effective distribution and storage. Fast thawing has been shown to increase cell recovery in vitrified samples. Previously, radiofrequency (RF) has been investigated as a heating source on large samples, either with or without magnetic particles. Also, laser heating with the aid of dye or nanoparticles has been utilized on sub–millimeter samples successfully. For slow freezing cryopreservation methods, the influence of rate of thawing on viability is less clear. Cryopreservation of surface adhered cells result in many cases in detachment from the surface. We illustrate how intense infrared radiation from a focused halogen illuminator accelerates thawing. We show that two epithelial cell lines, retinal pigment epithelium cells and heterogeneous human epithelial colorectal adenocarcinoma cells, can be effectively cryopreserved and recovered using a combination of slow freezing and fast thawing under infrared illumination. We were able to successfully thaw samples, of 2–4 mm thick, including the media, on the order of a second, providing a heating rate of thousands of Kelvin per minute. Under optimal conditions, we observed higher post–thawing cell viability rates and higher cell adhesion with infrared thawing than with water bath thawing. We suggest that bulk warming with infrared radiation has an advantage over surface warming of surface–attached cells, as it alleviates cell stress during the process of thawing. These findings will pave the way for novel approaches to treating substrate–adhered cells and 3D scaffolds with cells and organoids. This technology may serve as a crucial component in lab–on–chip systems for medical testing and therapeutic use.
Zaretsky, J. ; Griess-Fishheimer, S. ; Carmi, A. ; Travinsky Shmul, T. ; Ofer, L. ; Sinai, T. ; Penn, S. ; Shahar, R. ; Monsonego-Ornan, E. Ultra-processed food targets bone quality via endochondral ossification. 2021, 9 14. Publisher's VersionAbstract
Ultra-processed foods have known negative implications for health; however, their effect on skeletal development has never been explored. Here, we show that young rats fed ultra-processed food rich in fat and sugar suffer from growth retardation due to lesions in their tibial growth plates. The bone mineral density decreases significantly, and the structural parameters of the bone deteriorate, presenting a sieve-like appearance in the cortices and poor trabecular parameters in long bones and vertebrae. This results in inferior mechanical performance of the entire bone with a high fracture risk. RNA sequence analysis of the growth plates demonstrated an imbalance in extracellular matrix formation and degradation and impairment of proliferation, differentiation and mineralization processes. Our findings highlight, for the first time, the severe impact of consuming ultra-processed foods on the growing skeleton. This pathology extends far beyond that explained by the known metabolic effects, highlighting bone as a new target for studies of modern diets.
Zandani, G. ; Kaftori-Sandler, N. ; Sela, N. ; Nyska, A. ; Madar, Z. Dietary broccoli improves markers associated with glucose and lipid metabolism through modulation of gut microbiota in mice. 2021, 111240. Publisher's VersionAbstract
ObjectiveBroccoli is a “functional food” that contains bioactive compounds and phytochemicals that have beneficial health-promoting effects. This study aimed at investigating the effects of broccoli consumption on lipid and glucose metabolism and gut microbiota. Methods Male C57BL/6J mice (7–8 wk old) were fed ad libitum with a normal diet supplemented with or without 10% (w/w) broccoli florets or broccoli stalks. Oral glucose tolerance tests were performed at week 15. After 17 wk, blood and tissues were collected. Serum parameters, histology, gene and protein expression, and intestinal microbiota composition were evaluated. Results Stalk supplementation led to reductions in fasting glucose levels, serum insulin, and the homeostasis model assessment–insulin resistance (HOMA-IR) index. Liver enzymes improved in both experimental groups, and broccoli florets decreased total triacylglycerols. The stalks group had elevated fatty acid oxidation–related genes and proteins (AMPK, PPARα, and CPT1). Diverse microbiota populations were observed in both broccoli groups. Broccoli stalks were found to be richer in Akkermansia muciniphila, while broccoli florets reduced Mucispirillum schaedleri abundance and increased bacterial richness. Conclusions Long-term whole broccoli supplementation decreased inflammation, improved lipid parameters and insulin sensitivity, and altered the gut microbiome in mice. Our data provide new information regarding the potential benefits of broccoli stalks in metabolic parameters.
Margulis, E. ; Dagan-Wiener, A. ; Ives, R. S. ; Jaffari, S. ; Siems, K. ; Niv, M. Y. Intense bitterness of molecules: Machine learning for expediting drug discovery. 2021, 19, 568 - 576. Publisher's VersionAbstract
Drug development is a long, expensive and multistage process geared to achieving safe drugs with high efficacy. A crucial prerequisite for completing the medication regimen for oral drugs, particularly for pediatric and geriatric populations, is achieving taste that does not hinder compliance. Currently, the aversive taste of drugs is tested in late stages of clinical trials. This can result in the need to reformulate, potentially resulting in the use of more animals for additional toxicity trials, increased financial costs and a delay in release to the market. Here we present BitterIntense, a machine learning tool that classifies molecules into “very bitter” or “not very bitter”, based on their chemical structure. The model, trained on chemically diverse compounds, has above 80% accuracy on several test sets. Our results suggest that about 25% of drugs are predicted to be very bitter, with even higher prevalence (~40%) in COVID19 drug candidates and in microbial natural products. Only ~10% of toxic molecules are predicted to be intensely bitter, and it is also suggested that intense bitterness does not correlate with hepatotoxicity of drugs. However, very bitter compounds may be more cardiotoxic than not very bitter compounds, possessing significantly lower QPlogHERG values. BitterIntense allows quick and easy prediction of strong bitterness of compounds of interest for food, pharma and biotechnology industries. We estimate that implementation of BitterIntense or similar tools early in drug discovery process may lead to reduction in delays, in animal use and in overall financial burden.
Klein, H. ; Karni, N. ; Israel, S. ; Gross, M. ; Muszkat, M. ; Niv, M. Y. Reversible Taste Loss in a COVID-19 Patient With Preexisting Chronic Smell Impairment. Journal of Investigative Medicine High Impact Case ReportsJournal of Investigative Medicine High Impact Case Reports 2021, 9 2324709621990765. Publisher's VersionAbstract
Smell loss is important for coronavirus disease-2019 (COVID-19) screening and diagnosis. Particular attention should be paid to individuals with pre-COVID-19 chronic hyposmia or anosmia. We report a case of reversible taste impairment in a COVID-19 patient with chronically impaired sense of smell. This case emphasizes the importance of COVID-19-related taste assessment.
Klein, H. ; Asseo, K. ; Karni, N. ; Benjamini, Y. ; Nir-Paz, R. ; Muszkat, M. ; Israel, S. ; Niv, M. Y. Onset, duration and unresolved symptoms, including smell and taste changes, in mild COVID-19 infection: a cohort study in Israeli patients. 2021, 27, 769 - 774. Publisher's VersionAbstract
ObjectivesTo characterize longitudinal symptoms of mild coronavirus disease 2019 (COVID-19) patients for a period of 6 months, to potentially aid in disease management. Methods Phone interviews were conducted with 103 patients with mild COVID-19 in Israel over a 6-month period (April 2020 to October 2020). Patients were recruited via social media and word to mouth and were interviewed up to 4 times, depending on reports of their unresolved symptoms. Inclusion criteria required participants to be residents of Israel aged 18 years or older, with positive COVID-19 real-time PCR results and nonsevere symptoms. The onset, duration, severity and resolution of symptoms were analysed. Results A total of 44% (45/103), 41% (42/103), 39% (40/103) and 38% (39/103) of patients experienced headache, fever, muscle ache and dry cough as the first symptom respectively. Smell and taste changes were experienced at 3.9 ± 5.4 and 4.6 ± 5.7 days (mean ± standard deviation (SD)) after disease onset respectively. Among prevalent symptoms, fever had the shortest duration (5.8 ± 8.6 days), and taste and smell changes were the longest-lasting symptoms (17.2 ± 17.6 and 18.9 ± 19.7 days; durations censored at 60 days). Longer recovery of the sense of smell correlated with the extent of smell change. At the 6-month follow-up, 46% (47/103) of the patients had at least one unresolved symptom, most commonly fatigue (22%, 23/103), smell and taste changes (15%, 15/103 and 8%, 8/103 respectively) and breathing difficulties (8%, 8/103). Conclusions Long-lasting effects of mild COVID-19 manifested in almost half of the participants reporting at least one unresolved symptom after 6 months.
Itoigawa, A. ; Fierro, F. ; Chaney, M. E. ; Lauterbur, M. E. ; Hayakawa, T. ; Tosi, A. J. ; Niv, M. Y. ; Imai, H. Lowered sensitivity of bitter taste receptors to β-glucosides in bamboo lemurs: an instance of parallel and adaptive functional decline in TAS2R16?. Proceedings of the Royal Society B: Biological SciencesProceedings of the Royal Society B: Biological Sciences 2021, 288, 20210346. Publisher's Version
Israeli, H. ; Degtjarik, O. ; Fierro, F. ; Chunilal, V. ; Gill, A. K. ; Roth, N. J. ; Botta, J. ; Prabahar, V. ; Peleg, Y. ; Chan, L. F. ; et al. Structure reveals the activation mechanism of the MC4 receptor to initiate satiation signaling. Science 2021, eabf7958. Publisher's VersionAbstract
Obesity is a global epidemic causing morbidity and impaired quality of life. The melanocortin receptor 4 (MC4R) is at the crux of appetite, energy homeostasis, and body-weight control in the central nervous system and is a prime target for anti-obesity drugs. Here, we present the cryo-EM structure of the human MC4R-Gs signaling complex bound to the agonist setmelanotide, a cyclic peptide recently approved for the treatment of obesity. The work reveals the mechanism of MC4R activation, highlighting a molecular switch that initiates satiation signaling. In addition, our findings indicate that Ca2+ is required for agonist but not antagonist efficacy. These results fill a gap in understanding MC4R activation and could guide the design of future weight management drugs.
Ben Abu, N. ; Mason, P. E. ; Klein, H. ; Dubovski, N. ; Ben Shoshan-Galeczki, Y. ; Malach, E. ; Pražienková, V. ; Maletínská, L. ; Tempra, C. ; Chamorro, V. C. ; et al. Sweet taste of heavy water. 2021, 4 440. Publisher's VersionAbstract
Hydrogen to deuterium isotopic substitution has only a minor effect on physical and chemical properties of water and, as such, is not supposed to influence its neutral taste. Here we conclusively demonstrate that humans are, nevertheless, able to distinguish D2O from H2O by taste. Indeed, highly purified heavy water has a distinctly sweeter taste than same-purity normal water and can add to perceived sweetness of sweeteners. In contrast, mice do not prefer D2O over H2O, indicating that they are not likely to perceive heavy water as sweet. HEK 293T cells transfected with the TAS1R2/TAS1R3 heterodimer and chimeric G-proteins are activated by D2O but not by H2O. Lactisole, which is a known sweetness inhibitor acting via the TAS1R3 monomer of the TAS1R2/TAS1R3, suppresses the sweetness of D2O in human sensory tests, as well as the calcium release elicited by D2O in sweet taste receptor-expressing cells. The present multifaceted experimental study, complemented by homology modelling and molecular dynamics simulations, resolves a long-standing controversy about the taste of heavy water, shows that its sweet taste is mediated by the human TAS1R2/TAS1R3 taste receptor, and opens way to future studies of the detailed mechanism of action.
Chasnitsky, M. ; Yashunsky, V. ; Braslavsky, I. Heat flux balance description of unidirectional freezing and melting dynamics on a translational temperature gradient stage. 2021, 161, 106734. Publisher's VersionAbstract
Directional solidification occurs in industrial and natural processes, such as freeze-casting, metal processing, biological cryopreservation and freezing of soils. Translational temperature gradient stage allows to control the process of directional solidification and to visualize it with optical microscope. In this stage freezing velocity and temperature gradient are decoupled and are independently controlled. Here we study the dynamics of the phase transition interface in thin water samples using translational temperature gradient stage. We follow position of the ice–water interface with optical microscopy and compare it to solution of one dimensional Stefan problem in the low velocity limit. We find an agreement between experimental observations and theoretical predictions for constant velocity and during acceleration of the ice front. This work presents a practical framework for analysis and design of experiments on a translational temperature gradient stage.
Shumeiko, V. ; Paltiel, Y. ; Bisker, G. ; Hayouka, Z. ; Shoseyov, O. A nanoscale paper-based near-infrared optical nose (NIRON). Biosensors and Bioelectronics 2021, 172, 112763. Publisher's VersionAbstract
Electronic noses (e-nose) and optical noses (o-nose) are two emerging approaches for the development of artificial olfactory systems for flavor and smell evaluation. The current work leverages the unique optical properties of semiconducting single-wall carbon nanotubes (SWCNTs) to develop a prototype of a novel paper-based near-infrared optical nose (NIRON). We have drop-dried an array of SWCNTs encapsulated with a wide variety of peptides on a paper substrate and continuously imaged the emitted SWCNTs fluorescence using a CMOS camera. Odors and different volatile molecules were passed above the array in a flow chamber, resulting in unique modulation patterns of the SWCNT photoluminescence (PL). Quartz crystal microbalance (QCM) measurements performed in parallel confirmed the direct binding between the vapor molecules and the peptide-SWCNTs. PL levels measured before and during exposure demonstrate distinct responses to the four tested alcoholic vapors (ethanol, methanol, propanol, and isopropanol). In addition, machine learning tools directly applied to the fluorescence images allow us to distinguish between the aromas of red wine, beer, and vodka. Further, we show that the developed sensor can detect limonene, undecanal, and geraniol vapors, and differentiate between their smells utilizing the PL response pattern. This novel paper-based optical biosensor provides data in real-time, and is recoverable and suitable for working at room temperature and in a wide range of humidity levels. This platform opens new avenues for real-time sensing of volatile chemical compounds, odors, and flavors.