Ivana Tlak Gajger

Prof. Ivana Tlak Gajger

University of Zagreb - Faculty of Veterinary Medicine, Zagreb, Croatia
orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

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

Representative Publications

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14 May 2021 in Molecules
Verified
Journal Article
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JŠJelena Šuran
Jelena Šuran
ICIvica Cepanec
Ivica Cepanec
Tomislav MašekTomislav Mašek
Tomislav Mašek
BRBožo Radić
Božo Radić
SRSaša Radić
Saša Radić
Josipa VlainićJosipa Vlainić
Josipa Vlainić
Propolis is a honeybee product known for its antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. It is rich in bioactive molecules whose content varies depending on the botanical and geographical origin of propolis. These bioactive molecules have been studied individually and as a part of propolis extracts, as they can be used as representative markers for propolis standardization. Here, we compare the pharmacological effects of representative polyphenols and whole propolis extracts. Based on the literature data, polyphenols and extracts act by suppressing similar targets, from pro-inflammatory TNF/NF-κB to the pro-proliferative MAPK/ERK pathway. In addition, they activate similar antioxidant mechanisms of action, like Nrf2-ARE intracellular antioxidant pathway, and they all have antimicrobial activity. These similarities do not imply that we should attribute the action of propolis solely to the most representative compounds. Moreover, its pharmacological effects will depend on the efficacy of these compounds’ extraction. Thus, we also give an overview of different propolis extraction technologies, from traditional to modern ones, which are environmentally friendlier. These technologies belong to an open research area that needs further effective solutions in terms of well-standardized liquid and solid extracts, which would be reliable in their pharmacological effects, environmentally friendly, and sustainable for production.

24 February 2021 in Insects
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Journal Article
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Ivana Tlak GajgerIvana Tlak Gajger
Ivana Tlak Gajger
DDDr showket Ahmad Ahmad Dar
Dr showket Ahmad Ahmad Dar
In this review, we describe the role of plant-derived biochemicals that are toxic to insect pests. Biotic stress in plants caused by insect pests is one of the most significant problems, leading to yield losses. Synthetic pesticides still play a significant role in crop protection. However, the environmental side effects and health issues caused by the overuse or inappropriate application of synthetic pesticides forced authorities to ban some problematic ones. Consequently, there is a strong necessity for novel and alternative insect pest control methods. An interesting source of ecological pesticides are biocidal compounds, naturally occurring in plants as allelochemicals (secondary metabolites), helping plants to resist, tolerate or compensate the stress caused by insect pests. The abovementioned bioactive natural products are the first line of defense in plants against insect herbivores. The large group of secondary plant metabolites, including alkaloids, saponins, phenols and terpenes, are the most promising compounds in the management of insect pests. Secondary metabolites offer sustainable pest control, therefore we can conclude that certain plant species provide numerous promising possibilities for discovering novel and ecologically friendly methods for the control of numerous insect pests.

1 January 2021 in Saudi Journal of Biological Sciences
Verified
Journal Article
Open access
AUAmjad Ullah
Amjad Ullah
Ivana Tlak GajgerIvana Tlak Gajger
Ivana Tlak Gajger
AMArnold Majoros
Arnold Majoros
SDShowket Ahmad Dar
Showket Ahmad Dar
SKSanaullah Khan
Sanaullah Khan
SASyed Ishtiaq Anjum
Syed Ishtiaq Anjum
Honey bee is vital for pollination and ecological services, boosting crops productivity in terms of quality and quantity and production of colony products: wax, royal jelly, bee venom, honey, pollen and propolis. Honey bees are most important plant pollinators and almost one third of diet depends on bee’s pollination, worth billions of dollars. Hence the role that honey bees have in environment and their economic importance in food production, their health is of dominant significance. Honey bees can be infected by various pathogens like: viruses, bacteria, fungi, or infested by parasitic mites. At least more than 20 viruses have been identified to infect honey bees worldwide, generally from Dicistroviridae as well as Iflaviridae families, like ABPV (Acute Bee Paralysis Virus), BQCV (Black Queen Cell Virus), KBV (Kashmir Bee Virus), SBV (Sacbrood Virus), CBPV (Chronic bee paralysis virus), SBPV (Slow Bee Paralysis Virus) along with IAPV (Israeli acute paralysis virus), and DWV (Deformed Wing Virus) are prominent and cause infections harmful for honey bee colonies health. This issue about honey bee viruses demonstrates remarkably how diverse this field is, and considerable work has to be done to get a comprehensive interpretation of the bee virology.

1 December 2015 in Journal of Apicultural Science
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LSLidija Svečnjak
Lidija Svečnjak
GBGoran Baranović
Goran Baranović
Marko VincekovićMarko Vinceković
Marko Vinceković
PRPrđun
Prđun
PSPrđun Saša
Prđun Saša
SPSaša Prđun
Saša Prđun
Although beeswax adulteration represents one of the main beeswax quality issues, there are still no internationally standardised analytical methods for routine quality control. The objective of this study was to establish an analytical procedure suitable for routine detection of beeswax adulteration using FTIR-ATR spectroscopy. For the purpose of this study, reference IR spectra of virgin beeswax, paraffin, and their mixtures containing different proportions of paraffin (5 - 95%), were obtained. Mixtures were used for the establishment of calibration curves. To determine the prediction strength of IR spectral data for the share of paraffin in mixtures, the Partial Least Squares Regression method was used. The same procedure was conducted on beeswax-beef tallow mixtures. The model was validated using comb foundation samples of an unknown chemical background which had been collected from the international market (n = 56). Selected physico-chemical parameters were determined for comparison purposes. Results revealed a strong predictive power (R2 = 0.999) of IR spectra for the paraffin and beef tallow share in beeswax. The results also revealed that the majority of the analysed samples (89%) were adulterated with paraffin; only 6 out of 56 (11%) samples were identified as virgin beeswax, 28% of the samples exhibited a higher level of paraffin adulteration (>46% of paraffin), while the majority of the analysed samples (50%) were found to be adulterated with 5 - 20% of paraffin. These results indicate an urgent need for routine beeswax authenticity control. In this study, we demonstrated that the analytical approach defining the standard curves for particular adulteration levels in beeswax, based on chemometric modelling of specific IR spectral region indicative for adulteration, enables reliable determination of the adulterant proportions in beeswax.

1 November 2017 in Food Chemistry
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Journal Article
Closed access
NBNina Bilandžić
Nina Bilandžić
Ivana Tlak GajgerIvana Tlak Gajger
Ivana Tlak Gajger
MKMarina Kosanović
Marina Kosanović
BČBruno Čalopek
Bruno Čalopek
MSMarija Sedak
Marija Sedak
MĐMaja Đokić
Maja Đokić

17 September 2020 in Insects
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Journal Article
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Ivana Tlak GajgerIvana Tlak Gajger
Ivana Tlak Gajger
Josipa VlainićJosipa Vlainić
Josipa Vlainić
Petra ŠoštarićPetra Šoštarić
Petra Šoštarić
JPJanez Prešern
Janez Prešern
JBJernej Bubnič
Jernej Bubnič
Maja Ivana Smodis SkerlMaja Ivana Smodis Skerl
Maja Ivana Smodis Skerl
Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM® for bees could potentially have an important therapeutic and immunomodulatory effect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies’ strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies’ strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic.