S transfuzijo povezana reakcija presadka proti gostitelju (angl. Transfusion associated graft versus host disease, TA-GvHD) je redek, vendar resen in življenje ogrožajoč zaplet po transfuziji krvnih ...pripravkov. Posledica, kolikor do nje pride, je bolnikova smrt v več kot 90 % primerov. Po transfuziji krvi se osebi z imunsko pomanjkljivostjo limfociti T iz darovalčeve krvi odzovejo na celične in tkivne antigene prejemnika krvi. Zato darovalčevi limfociti T aktivirajo in uničijo tarčne celice v tkivih prejemnika. Vzrok, da se imunske celice prejemnika ne odzovejo tako, da bi onemogočile darovalčeve limfocite T, je pomanjkljivost imunskega odziva pri prejemniku in le izjemoma vprašanje skladnosti HLA med prejemnikom in darovalcem.
Obsevanje krvnih pripravkov z ionizirajočimi žarki je najbolj učinkovita metoda za preprečevanje TA-GvHD. Patogensko inaktiviranje s psoralenom in UVA-žarki je enakovredno obsevanju, vendar se zaenkrat uporablja samo za trombocitne pripravke. Zato je pomembno, da lečeči zdravnik prepozna bolnike, pri katerih lahko nastane TA-GvHD in za njih naroča zgolj obsevane krvne pripravke. Obsevamo eritrocite, granulocite ter trombocite, kadar niso patogensko inaktivirani. Sveže zmrznjene plazme, krioprecipitata, zdravil iz krvi, kot so albumin, imunoglobulini, faktorji strjevanja krvi ... ter eritrocitov po odmrzovanju ne obsevamo, ker je vsebnost limfocitov T zanemarljiva. Priporočen osrednji obsevalni odmerek je znotraj 25–50 Gy.
Apple species are the unique naturally rich source of dihydrochalcones, phenolic compounds with an elusive role
in planta,
but suggested auto-allelochemical features related to “apple replant ...disease” (ARD). Our aim was to elucidate the physiological basis of the phytotoxic action of dihydrochalcone phloretin in the model plant Arabidopsis and to promote phloretin as a new prospective eco-friendly phytotoxic compound. Phloretin treatment induced a significant dose-dependent growth retardation and severe morphological abnormalities and agravitropic behavior in Arabidopsis seedlings. Histological examination revealed a reduced starch content in the columella cells and a serious disturbance in root architecture, which resulted in the reduction in length of meristematic and elongation zones. Significantly disturbed auxin metabolome profile in roots with a particularly increased content of IAA accumulated in the lateral parts of the root apex, accompanied by changes in the expression of auxin biosynthetic and transport genes, especially
PIN1
,
PIN3
,
PIN7
, and
ABCB1
, indicates the role of auxin in physiological basis of phloretin-induced growth retardation. The results reveal a disturbance of auxin homeostasis as the main mechanism of phytotoxic action of phloretin. This mechanism makes phloretin a prospective candidate for an eco-friendly bioherbicide and paves the way for further research of phloretin role in ARD.
The main goal of environmental education is the development of environmental
awareness, which is the basis for pro-environmental behavior. In order to
determine the conditions which, favour the ...development of environmental
awareness, a survey was conducted of students in the fourth grade of primary
school, based on data from TIMSS 2019. The criterion variable was the score
on the Environmental Awareness Scale, while the predictor variables included
characteristics which vary at student, class, and school levels.
Hierarchical linear modeling indicated the importance of variables at the
individual level: home resources, literacy and numeracy readiness for
school, confidence in science, usefulness of science lessons, and parent?s
perceptions of their child?s school and expected student education level.
None of the considered class and school level variables were significant
predictors of environmental awareness. Between-school differences were fully
explained by the final, retained model, but some variance (approx. 8%)
between different classes remained unexplained by the considered predictor
variables. We offer suggestions on how to increase the school?s
contribution to the development of students? environmental awareness through
the application of effective pedagogy and school improvement. Further
research is needed into the contribution of the educational environment.
The present study evaluates the phytotoxic effects of phloretin, a prevalent secondary metabolite of apple trees, on the broadleaf weed Capsella bursa-pastoris (L.) Medik. known for its resistant ...myxospermous seeds that form a long-lasting soil bank. The results indicate a significant, dose-dependent inhibitory effect of phloretin on the growth and morphological parameters of weed seedlings grown in vitro. Although the applied phloretin concentrations (250–1000 µM) were not lethal to the C. bursa-pastoris seedlings after two weeks, the metabolism of the seedlings was impaired, resulting in an accumulation of lipid droplets in the root tips and root hairs. Histochemical analysis shows deposits of phenols in the root epidermal cells, which are probably aggregates of phloretin or its metabolic derivatives. The accumulation of pectin in the cell walls of root border cells in phloretin-treated seedlings indicates an attempt to reduce the uptake of phloretin and reduce its concentration in the cells. Inhibition of shoot growth associated with chlorosis and reduced photosynthetic pigment content is a consequence of seedling exposure to phloretin. This study provides a basis for further evaluation of phloretin as a new bioherbicidal compound and for elucidating the mechanism underlying its phytotoxic activity.
The protection of human health and the preservation of the environment are topics that form an integral part of the primary school curriculum in Serbia. However, research studies have shown that ...students do not have enough knowledge to contribute to the development of a healthy lifestyle and environmental awareness. The latest changes in school policy and curricula confirm that the relevance of environmental education has been recognized, but changes in school practice are yet to come. This article discusses the challenges encountered in the implementation of the intended curriculum and offers suggestions for changes to the curriculum, pedagogy, and teacher training in order to enhance environmental education.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Allelopathic plants exploit their chemical 'weapons' to prevail over the competition, suppress neighboring plants and consequently use the available resources more efficiently. However, the ...investigation of plant allelopathic interactions in rhizosphere is difficult to perform because of its high complexity due to interactions of biotic and abiotic factors. Thus, autonomous, aseptic root cultures of apple (Malus × domestica Borkh.) could facilitate allelopathic studies. We report on the successful genetic transformation of apple cultivars Melrose, Golden Delicious, Čadel and Gloster using Agrobacterium rhizogenes (Riker et al. 1930) Conn 1942 strain 15834 and for the first time the establishment of apple autonomous and permanent in vitro hairy root cultures that could be used as a new tool for apple allelopathic assays. Molecular characterization of transgenic hairy root lines was conducted to elucidate the possible relationship between expression of T-DNA genes and root growth characteristics that include branching. Similar content of phenolic acids (chlorogenic, caffeic, syringic, p-coumaric and ferulic), glycosilated flavonoids (rutin, quercitrin, isoquercitrin, kaempferol-3-glucoside) and flavonoid aglycones (quercetin and naringenin), and dihydrochalcone phloridzin, was detected in untransformed and transgenic apple root tissue by ultra high-performance liquid chromatography with mass spectrometry (UHPLC/(+/-)HESI-MS/MS) analyses, confirming that genetic transformation did not disturb secondary metabolite production in apple. Chlorogenic and caffeic acids and dihydrochalcones phloridzin and phloretin were detected as putative allelochemicals exuded into the growth medium in which transgenic roots were maintained for 4 weeks. Apple hairy root exudates significantly affected shoot and root development and growth of test plant Arabidopsis thaliana (L.) Heynh. seedlings after 5 or 10 days of treatment. Additionally, core cell-cycle genes CDKA1;1, CDKB2;1, CYCA3;1 and CYCB2;4 were down regulated in Arabidopsis shoots suggesting, in part, their role in inhibition of shoot growth. The present work highlighted an autonomous and permanent in vitro hairy root culture system as a valuable tool for studying allelopathic potential of apple, offering new perspective for allelopathy background elucidation in this important fruit species.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Since the genetic transformation of the apple is strongly genotype-dependent and generally inefficient, the evaluation of factors affecting shoot regeneration are crucial for the establishment of a ...successful transformation process. In this report, we evaluated the effects of the ?-lactam antibiotics meropenem and timentin on in vitro regeneration via de novo shoot organogenesis from leaf explants of apple cv. Golden Delicious, as well as on the growth of the Agrobacterium tumefaciens strain EHA 105, and compared them with the commonly used ?-lactam cefotaxime. Also, we report for the first time the effect of hygromycin B as a selective agent in the domesticated apple, as regards shoot regeneration and shoot multiplication efficiency. We observed that cefotaxime and timentin at concentrations higher than 100 mg L-1 were sufficient to prevent Agrobacterium growth during a two-week period, while meropenem exhibited an inhibitory effect on bacterial growth at all tested concentrations (25-150 mg L-1). Cefotaxime at a concentration of 300 mg L-1 increased the number of regenerated shoots per explant (9.39) in comparison with the control (7.67). In contrast to cefotaxime, meropenem and timentin caused a decrease in shoot regeneration efficiency, but larger and more developed shoots were obtained on meropenem (25-125 mg L-1) after the same period of cultivation. Hygromycin B at a concentration of 5 mg L-1 or higher completely inhibited shoot regeneration and induced explant tissue necrosis. Therefore, the selection procedure with a final concentration of 4 mg L-1 throughout organogenesis and 10 mg L-1 for further shoot growth and multiplication is recommended for an efficient transformation process in apple cv. Golden Delicious.
Chenopodium murale
L. is an invasive weed species significantly interfering with wheat crop. However, the complete nature of its allelopathic influence on crops is not yet fully understood. In the ...present study, the focus is made on establishing the relation between plant morphophysiological changes and oxidative stress, induced by allelopathic extract. Phytotoxic medium of
C. murale
hairy root clone R5 reduced the germination rate (24% less than control value) of wheat cv. Nataša seeds, as well as seedling growth, diminishing shoot and root length significantly, decreased total chlorophyll content, and induced abnormal root gravitropism. The R5 treatment caused cellular structural abnormalities, reflecting on the root and leaf cell shape and organization. These abnormalities mostly included the increased number of mitochondria and reorganization of the vacuolar compartment, changes in nucleus shape, and chloroplast organization and distribution. The most significant structural changes were observed in cell wall in the form of amoeboid protrusions and folds leading to its irregular shape. These structural alterations were accompanied by an oxidative stress in tissues of treated wheat seedlings, reflected as increased level of H
2
O
2
and other ROS molecules, an increase of radical scavenging capacity and total phenolic content. Accordingly, the retardation of wheat seedling growth by
C. murale
allelochemicals may represent a consequence of complex activity involving both cell structure alteration and physiological processes.
The aim of this study was to evaluate the occurrence of total aflatoxins
(AFs) and type-B fumonisins (FBs) in 65 maize grain samples collected during
harvest in 2018 (13 samples), 2019 (11 samples), ...2020 (9 samples), 2021 (14
samples) and 2022 (18 samples) from different locations in suburb of
Belgrade (Republic of Serbia). The average levels of AFs and FBs in
mycotoxin-positive samples were 5.43 and 2910 ?g kg-1 (2018), 5.28 and 2710
?g kg-1 (2019), 2.35 and 10980 ?g kg-1 (2020), 6.81 and 4950 ?g kg-1 (2021)
and 5.32 and 20310 ?g kg-1 (2022), respectively. In 23.08% (2018), 18.18%
(2019), 22.22% (2020), 64.29% (2021) and 27.78% (2022) of maize samples, the
co-occurrence of AFs and FBs was established. The maximum limits of 10 ?g
kg-1 for AFs in maize and 4000 ?g kg-1 for FBs in unprocessed maize
prescribed by regulations of Serbia and the European Union were exceeded for
AFs in 14.29% (2021) and 5.56% (2022) of maize samples and for FBs in 7.69%
(2018), 66.67% (2020), 28.57% (2021) and 41.67% (2022) of maize samples.
Multiple linear regression analyses showed a statistically significant
influence of climate factors (air temperature, relative humidity and total
rainfall) in July-September (2018-2022) on FBs levels. These results
indicate the need for continuous monitoring of the health status of
harvested maize grains and risk assessment of the potential presence of
mycotoxins in the food chain to avoid adverse effects on human and animal
health.
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