Jaroslav Havlik

Dr. Jaroslav Havlik

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 November 2017 in Nutrition Bulletin
Verified
Journal Article
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CEChristine Edwards
Christine Edwards
JHJaroslav Havlik
Jaroslav Havlik
WCWenjuan CONG
Wenjuan CONG
WMW. Mullen
W. Mullen
TPT. Preston
T. Preston
Emilie CombetEmilie Combet
Emilie Combet
A high‐fibre diet and one rich in fruit and vegetables have long been associated with lower risk of chronic disease. There are several possible mechanisms underpinning these associations, but one likely important factor is the production of bioactive molecules from plant‐based foods by the bacteria in the colon. This links to our growing understanding of the role of the gut microbiome in promoting health. Polyphenolic‐rich plant foods have been associated with potential health effects in many studies, but the bioavailability of polyphenol compounds, as eaten, is often very low. Most of the ingested molecules enter the large intestine where they are catabolised to smaller phenolic acids that may be the key bioactive effectors. Dietary fibres, present in plant foods, are also fermented by the bacteria to short‐chain fatty acids, compounds associated with several beneficial effects on cell turnover, metabolism and eating behaviour. Polyphenols and fibre are often eaten together, but there is a lack of research investigating the interaction between these two groups of key substrates for the colonic bacteria. In a project funded by the Biotechnology and Biological Sciences Research Council Diet and Health Research Industry Club, we are investigating whether combining different fibres and polyphenol sources can enhance the production of bioactive phenolic acids to promote health. This could lead to improved dietary recommendations and to new products with enhanced potential health‐promoting actions.

1 March 2011 in Solar Energy
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Journal Article
Closed access
JBJan Banout
Jan Banout
PEP. Ehl
P. Ehl
JHJaroslav Havlik
Jaroslav Havlik
Bohdan LojkaBohdan Lojka
Bohdan Lojka
ZPZbynek Polesny
Zbynek Polesny
Vladimir VernerVladimir Verner
Vladimir Verner

13 March 2015 in PLOS ONE
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Journal Article
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ZHZuzana Hroncova
Zuzana Hroncova
JHJaroslav Havlik
Jaroslav Havlik
JKJiří Killer
Jiří Killer
IDIvo Doskocil
Ivo Doskocil
JTJan Tyl
Jan Tyl
VRVojtech Rada
Vojtech Rada
Social honey bees, Apis mellifera, host a set of distinct microbiota, which is similar across the continents and various honey bee species. Some of these bacteria, such as lactobacilli, have been linked to immunity and defence against pathogens. Pathogen defence is crucial, particularly in larval stages, as many pathogens affect the brood. However, information on larval microbiota is conflicting. Seven developmental stages and drones were sampled from 3 colonies at each of the 4 geographic locations of A. mellifera carnica, and the samples were maintained separately for analysis. We analysed the variation and abundance of important bacterial groups and taxa in the collected bees. Major bacterial groups were evaluated over the entire life of honey bee individuals, where digestive tracts of same aged bees were sampled in the course of time. The results showed that the microbial tract of 6-day-old 5th instar larvae were nearly equally rich in total microbial counts per total digestive tract weight as foraging bees, showing a high percentage of various lactobacilli (Firmicutes) and Gilliamella apicola (Gammaproteobacteria 1). However, during pupation, microbial counts were significantly reduced but recovered quickly by 6 days post-emergence. Between emergence and day 6, imago reached the highest counts of Firmicutes and Gammaproteobacteria, which then gradually declined with bee age. Redundancy analysis conducted using denaturing gradient gel electrophoresis identified bacterial species that were characteristic of each developmental stage. The results suggest that 3-day 4th instar larvae contain low microbial counts that increase 2-fold by day 6 and then decrease during pupation. Microbial succession of the imago begins soon after emergence. We found that bacterial counts do not show only yearly cycles within a colony, but vary on the individual level. Sampling and pooling adult bees or 6th day larvae may lead to high errors and variability, as both of these stages may be undergoing dynamic succession.

1 December 2008 in Journal of Food Protection
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Journal Article
Closed access
Ladislav KokoskaLadislav Kokoska
Ladislav Kokoska
JHJaroslav Havlik
Jaroslav Havlik
IVIrena Valterova
Irena Valterova
HSHelena Sovova
Helena Sovova
MSM. Sajfrtova
M. Sajfrtova
IJI. Jankovska
I. Jankovska
Nigella sativa L. seed essential oils obtained by hydrodistillation (HD), dry steam distillation (SD), steam distillation of crude oils obtained by solvent extraction (SE-SD), and supercritical flu...

1 November 2016 in Revista Brasileira de Farmacognosia
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Journal Article
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JTJan Tauchen
Jan Tauchen
LBLudvik Bortl
Ludvik Bortl
LHLukas Huml
Lukas Huml
PMPetra Miksatkova
Petra Miksatkova
IDIvo Doskocil
Ivo Doskocil
LKLadislav Kokoska
Ladislav Kokoska
Among 23 extracts of medicinal and edible plants tested, Mauritia flexuosa L.f., Arecaceae, showed significant antioxidant ability (DPPH and ORAC = 1062.9 and 645.9 +/- 51.4 mu g TE/mg extract, respectively), while Annona montana Macfad., Annonaceae, demonstrated the most promising anti-proliferative effect (IC50 for Hep-G2 and HT-29 = 2.7 and 9.0 mu g/ml, respectively). However, combinatory antioxidant/anti-proliferative effect was only detected in Oenocarpus bataua Mart., Arecaceae (DPPH = 903.8 and ORAC = 1024 mu g TE/mg extract; IC50 for Hep-G2 and HT-29 at 102.6 and 38.8 mu g/ml, respectively) and Inga edulis Mart., Fabaceae (DPPH = 337.0 and ORAC = 795.7 mu g TE/mg extract; IC50 for Hep-G2 and HT-29 at 36.3 and 57.9 mu g/ml, respectively). Phenolic content was positively correlated with antioxidant potential, however not with anti-proliferative effect. None of these extracts possessed toxicity towards normal foetal lung cells, suggesting their possible use in development of novel plant-based agents with preventive and/or therapeutic action against oxidative stress-related diseases

10 September 2009 in Plant Growth Regulation
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Journal Article
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HSHamid Sodaeizadeh
Hamid Sodaeizadeh
MRMohammad Rafieiolhossaini
Mohammad Rafieiolhossaini
JHJaroslav Havlik
Jaroslav Havlik
PDPatrick Van Damme
Patrick Van Damme