The effect of 2,4-D on the photosynthetic apparatus in cotyledons of spruce (Picea abies L. Karst.) seedlings grown in the dark

Growth regulating substance, 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used in plant cell cultures and also in agriculture as a herbicide. The effect of 2,4-D on photosynthetic pigment content and chloroplast ultrastructure in spruce seedlings grown in the dark was studied. Seedlings were grown for 16 days in the dark at room temperature in Petri dishes moistened either with tap water (control) or 4.5, 45 and 450 μM 2,4-D. The lowest concentration (4.5 μM) of 2,4-D induced both chlorophyll and carotenoid biosynthesis as compared to the control treatment. There were no statistically significant differences in any of the measured parameters between the control and the 45 μM 2,4-D treatment. A herbicidal concentration of 2,4-D (450 μM) induced a decline in chlorophyll content, while carotenoids were not significantly influenced. In contrast to the low concentration treatments, a herbicidal concentration of 2,4-D caused extensive changes in chloroplast shape and ultrastructure

Utjecaj temperature pohranjivanja na aktivnost ukupnih peroksidaza u nepročišćenom ekstraktu iglica smreke (Picea abies L. Karst.)

Peroxidases are enzymes with numerous functions in plant cells and are, therefore, interesting objects of current biochemical research. The purpose of this work was to investigate the effect of 30 days storage at different temperatures on the peroxidase activity in crude extracts from one-year old needles of Picea abies L. Karst. Total peroxidase activity was detected in the extract reaction with guaiacol and H2O2. Colour product was quantified by absorbance measurement at 470 nm. Measurements were performed daily in the first 10 days, and on the 12th, 14th, 16th, 18th and 30th day of the experiment. Extracts stored for 30 days were subjected to polyacrylamide gel electrophoresis, incubated with peroxidase substrates, and the resulting bands were quantified. Three different dependences on storage temperature were noticed. Extracts kept at –196 °C and –20 °C displayed no change in activity, samples kept at +24 °C and +37 °C decreased the activity, while those kept at +4 °C manifested a considerable rise in activity. Electropherogram analysis revealed two isoenzymes, with total activities resembling those obtained spectrophotometrically. There was no difference in isoenzyme appearance between samples. Recommendations regarding enzyme extract storage are given.Peroksidaze su enzimi s brojnim funkcijama u biljnim stanicama. Stoga su ovi enzimi zanimljiv predmet suvremenih biokemijskih istraživanja. Svrha ovoga rada bila je ispitati utjecaj pohranjivanja kroz 30 dana pri različitim temperaturama na aktivnost ukupnih peroksidaza u nepročišćenom ekstraktu iz jednogodišnjih iglica smreke. Aktivnost ukupnih peroksidaza određivana je reakcijom proteinskoga ekstrakta s gvajakolom i H2O2. Količina obojenoga produkta proporcionalna je apsorbanciji na 470 nm. Mjerenja su vršena svaki dan prvih 10 dana, a nakon toga u slijedeće dane pokusa: 12., 14., 16., 18. i 30. Ekstrakti pohranjeni 30 dana bili su podvrgnuti nativnoj elektroforezi na poliakrilamidnome gelu te inkubirani sa supstratima peroksidaza, a intenzitet obojenja vrpci kvantitativno je određen. Uočene su tri različite ovisnosti o temperaturi pohranjivanja. Ekstrakti čuvani na –196 °C i –20 °C nisu promijenili aktivnost, uzorcima čuvanim na +24 °C i +37 °C aktivnost se smanjila, dok se onima čuvanim na +4 °C povećala. Analiza elektroferograma pokazala je postojanje dva izoenzima, pri čemu je zbroj njihovih pojedinačnih aktivnosti za svaku temperaturu pohranjivanja sličan onoj izmjerenoj spektrofotometrijski. Nije bilo razlike u broju i udjelu izoenzima između uzoraka. Preporuča se određ eni način pohranjivanja enzimskoga ekstrakta iz iglica smreke.

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves

Changes in Photosystem II Photochemistry in Senescing Maple Leaves

Biochemical and functional changes in photosystem II (PSII) were investigated during natural senescence of maple (Acer platanoides L.) leaves. Three different types of senescing leaves were used: early senescent green (G), yellow green (YG) and yellow (Y). The main goal of this study was to investigate the dynamics of degradation of major photosynthetic proteins (D1, LHCII and Rubisco LSU) and how this would reflect on PSII photochemistry. It was revealed that D1 and LSU degrade faster than LHCII. Such differential degradation dynamics influenced PSII photochemistry. A decrease in the maximum (Fv/Fm) and effective (ΔF/F\u27m) quantum yields of PSII as well as a decrease in its capability for O2 evolution were observed. Analysis of chlorophyll a fluorescence transient measurement (OJIP test) in senescent leaves showed striking decrease in performance index (PIABS), a measure of overall photosynthetic performance. Further, increased absorption, trapping and dissipation of excitation energy per reaction centre were found in senescent leaves. In addition, it was shown that a marked decrease in electron transport beyond the primary electron acceptor (QA) in Y leaves was due to reduced electron transfer ability from QA– to QB. It can be concluded that molecular and functional modifications of a certain fraction of reaction centres from active to dissipative might be considered an important regulatory mechanism in chloroplast electron-transport chain redox poise control during natural senescence of maple leaves

Simbolika sablje u Yoshikawinom romanu Musashi

In his masterpiece Musashi (1935), the author Eiji Yoshikawa depicts the birth of an ingenious swordsman and his spiritual evolution towards the final awakening (satori). While constructing the character of Miyamoto Musashi, Yoshikawa uses the elements of Zen Buddhist philosophy and describes Musashi\u27s progress on his way of enlightenment through a series of direct personal insights (kensho) that precede satori. The paper aims to discuss and analyze Musashi\u27s use of different types of swords that metaphorically suggest his personal and spiritual transformation from an untamed and uncultivated person to his ultimate enlightenment. Initially, Musashi fights with a wooden sword (bokken), which symbolizes his animalistic, rampant nature. As he progresses on the way of enlightenment, Musashi embraces the steel sword (katana), though he still uses bokken at times. The struggle between his wild and civilized nature culminates at the moment of kensho, when he starts fighting with two steel swords, which represents a true evolution that elevates him to the level of the Nietzschean Übermensch. The final birth of Musashi as a Rinzaian “man of no rank” is the moment of his ultimate awakening, symbolically depicted when he again reaches for the wooden sword. This act unmasks his true Buddhist nature, thus suggesting Musashi\u27s return to “oneself.

Gvajakol-peroksidaze i fotosintetski pigmenti u različito starim iglicama smreke

Changes in the guaiacol peroxidases activity, electrophoretic pattern, photosynthetic pigments content and photosystem II efficiency in spruce (Picea abies L. Karst.) needles of different ages were investigated. Four generations of needles (current-year, one-, two- and three-yearold) were collected from ten Norway spruce trees. Similar Fv/Fm values (the ratio of variable and maximal fluorescence) in all investigated needles indicate that they were healthy with a fully functional photosystem II. There was a significant increase in photosynthetic pigments content during the first year of development. Total guaiacol peroxidases activity was increasing continuously during needles maturation. Significant differences were recorded between the current-year and older needles, as well as between the one-year-old and three-year-old needles. Also, the expression of new isoforms of peroxidases was observed in one-year old needles compared to current-year needles. No differences in the isoperoxidase pattern were observed between one-, two- and three year-old needles. The obtained results show that Norway spruce needles were subject to most pronounced biochemical and molecular changes during the first year of development.Proučavane su promjene u aktivnosti gvajakol-peroksidaza, u elektroforetskome sastavu, u sadržaju fotosintetskih pigmenata i učinkovitosti fotosustava II u iglicama smreke (Picea abies L. Karst.) različite starosti. Četiri generacije iglica (ovogodišnje, jedno-, dvo- i trogodišnje) prikupljene su s deset stabala smreke. Slične Fv/Fm vrijednosti u svim ispitivanim iglicama pokazuju da su zdrave s potpuno funkcionalnim fotosustavom II. Značajno povećanje sadržaja fotosintetskih pigmenata se dogodilo tijekom prve godine razvoja. Ukupna aktivnost gvajakol-peroksidaza povećavala se kontinuirano tijekom starenja iglica. Statistička značajnost utvrđena je između ovogodišnjih i starijih iglica te između jednogodišnjih i trogodišnjih iglica. Pojava novih izoformi peroksidaza uočena je u jednogodišnjim iglicama u odnosu na ovogodišnje iglice. Između jednogodiš njih, dvogodišnjih i trogodišnjih iglica nisu uočene promjene u sastavu izoformi peroksidaza. Dobiveni rezultati pokazuju da iglice smreke podliježu najintenzivnijim biokemijskim i molekularnim promjenama tijekom prve godine razvoja

Epigenetics and major depression disorder

Veliki depresivni poremećaj (MDD, od engl. Major Depressive Disorder) jedan je od najčešćih psihosomatskih poremećaja, sa snažnom tendencijom porasta broja oboljelih. Do 2020. godine mogao bi postati drugi najveći zdravstveni svjetski problem. Uzroci nastanaka bolesti, kao i klinička slika, vrlo su složeni. Ovakva složenost posljedica je aktivnosti velikog broja gena, od kojih svaki „pridonosi“ nastanku i izražaju bolesti s relativno malim udjelom. Sve veći broj rezultata mnogih studija upućuje na važnost epigenetičkih mehanizama regulacije aktivnosti gena, kao poveznicu bioloških i drugih čimbenika koji se povezuju s nastankom depresije. Većina istraživanja pokazuje uzročno-posljedičnu vezu između različitih bioloških i psihosocijalnih čimbenika, s jedne strane, te međuovisne promjene obrazaca metilacije/demetilacije molekule DNK i promjene koda histona, s druge strane. Sve je više podataka o značajnoj ulozi različitih nekodirajućih molekula RNK u nastanku depresivnog poremećaja. Konačno, pokazalo se da mnogi antidepresivi djeluju na epigenom. Ovaj učinak otvara potpuno novo poglavlje u razumijevanju patogeneze i epigenetičke podloge liječenja depresivnog poremećaja.Major Depressive Disorder (MDD) represents one of the most common psychosomatic disorders with a pronounced increasing incidence. It is expected to become the number two major world health problem by 2020. The causes of MDD as well as its clinical features are very complex. The probable reason for such complexity relates to a large number of genes, being involved in a condition where each gene makes only a minor contribution to the MDD etiology and clinic phenotypes. An increasing number of studies published during last decade have pointed out the importance of epigenetic regulatory mechanisms in affecting gene activity as well as constituting a possible link between biological and other factors related to MDD. Most of the studies have shown causality between different, MDD related biological and psycho-social factors. They have also described mutually controlled processes involved in the regulation of DNA methylation and establishment of histone code. There is a growing body of evidence on the significant role of non-coding RNA molecules in the ethiopathogenesis of MDD. Finally, it was shown that many antidepressive agents exert much influence on the epigenome. Such activity opens a new chapter in understanding the MDD pathogenesis and the basis for epigenome-reshaping related therapy

Fotokemija fotosustava II u CYP38 delecijskom mutantu biljke Arabidopsis thaliana

Chloroplast protein CYP38 is a cyclophilin-like peptidyl-prolyl cis-trans isomerase involved in photosystem II (PSII) assembly. It also serves as a regulator of thylakoid protein phosphatase. In this work the efficiency of PSII in CYP38 deficient Arabidopsis thaliana M13 plants has been analyzed by measuring in vivo chlorophyll a (Chl a) fluorescence transient (OJIP test). Significant differences in overall photosynthetic performance (PIABS), absorption (ABS/RC), trapping (TRo/RC), electron transport (ETo/RC), and dissipation (DIo/RC) were observed between A. thaliana M13 and the wild type (WT) plants. Increased Chl a and Chl b levels, as well as decreased Chl a/Chl b ratio were measured in M13 plants, indicating the adjustment of PSII antenna for increasing light absorption capability. Based on the obtained results, it can be concluded that the deficiency in CYP38 protein leads to impaired function of PSII due to the conversion of a certain fraction of active reaction centres to dissipative ones. This leads to a decrease in overall photosynthetic performance (PIABS) in M13 plants. Such effect was due to lowering of TRo/DIo parameter, which was influenced mostly by significant increases in energy dissipation (DIo/RC) and in trapping of electrons (TRo/RC) per active reaction centre.Kloroplastni je protein CYP38 peptidil-prolil cis-trans izomeraza slična ciklofilinima, a sudjeluje u izgradnji fotosustava II (PSII). Istodobno ovaj protein služi kao regulator tilakoidne proteinske fosfataze. U ovom je radu analizirana učinkovitost PSII u CYP38 delecijskom mutantu biljke Arabidopsis thaliana korištenjem in vivo mjerenja kratkotrajne promjene fluorescencije klorofila (Chl) (OJIP test). Značajno smanjenje fotosintetske učinkovitosti (PIABS), apsorpcije (ABS/RC), hvatanja elektrona (TRo/RC), prijenosa elektrona (ETo/RC) i disipacije (DIo/RC) uočeno je u skupini biljaka M13 u usporedbi s divljim tipom (WT) A. thaliana. U skupini M13 biljaka izmjeren je povećani udjel Chl a i Chl b i smanjeni omjer Chl a/Chl b, što upućuje na prilagodbe antena PSII za povećanim kapacitetom apsorpcije svjetla. S obzirom na dobivene rezultate može se zaključiti da pomanjkanje proteina CYP38 uzrokuje slabljenje funkcije PSII zbog konverzije nekog broja aktivnih reakcijskih centara u disipativne centre, što dovodi do smanjenja ukupne fotosintetske učinkovitosti (PIABS) u skupini biljaka M13. Ovaj se učinak može objasniti snizivanjem parametra TRo/DIo, što je uglavnom uzrokovano značajnim povećanjem rasipanja energije (DIo/RC) i hvatanja elektrona (TRo/RC) po aktivnom reakcijskom centru

Photosynthetic Electron Transport and Superoxide Dismutase Activity during Natural Senescence of Maple Leaves

Natural senescence of maple (Acer pseudoplatanus L.) leaves was investigated. Three types of senescing leaves were used: green (G), yellow-green (YG) and yellow (Y) ones. Down regulation of photosynthetic performance was achieved due to significant degradation of total chlorophylls, decrease in maximum quantum yield of PSII (Fv/Fm) and relative electron transport rate (rel. ETR). Also, decrease in Rubisco LSU abundance as well as degradation of rbcL gene was shown in YG and Y leaves. Senescent leaves revealed significant increase in the capacity of PSII for oxygen evolution when expressed per chlorophyll unit. This was the most probable source of reactive oxygen species (ROS) excess. The level of SOD (superoxide dismutase) activity increased 3.5-fold in Y leaves in respect to G and YG leaves. The increase in ROS level as well as in SOD activity during natural senescence of maple leaves was associated with increased level of lipid peroxidation and protein carbonyl content

Comparative Study of Leaf Anatomy and Certain Biochemical Traits in Two Olive Cultivars

Olive (Olea europea L.) is one of the most cultivated trees in Dalmatia (Croatia). The aim of this work was to compare leaf anatomy, guaiacol peroxidases activity and soluble polyphenols content in two olive cultivars: Oblica and Leccino, to get preliminary data for further investigations of stress influence on their growth and productivity. Leaves from fi ve two–years–old trees of each, Olea europaea L. cv. Oblica and cv. Leccino were used in this study. Composed sample of each cultivar was used for determination of guaiacol peroxidases activity (GPOD), content of soluble polyphenols (PHEN) and dry weight (DW). The presence of lignin, suberin and callose were analyzed by histochemical reactions on fresh hand-made leaf sections. The leaf anatomy was studied on 3 μm thin sections stained with Toluidine blue O. There were significant differences of tissue areas between two olive cultivars. Bigger areas of upper and lower epidermis in cultivar Leccino leaves as well as bigger areas of schlerenchyma, idioblasts and intercellulars in leaves of cultivar Oblica were measured. Oblica had higher activity of GPOD and portion of DW than Leccino. Higher PHEN content was measured in Leccino leaves. Histochemical reactions showed more lignin and suberin in cultivar Oblica leaves. Based on the presented results, cultivars Oblica and Leccino should response differently on cold, salt and drought stress that should be the scope in further investigations