Identifikacija Eutypa lata, parazita vinove loze

The phytopathogenic fungus Eutypa lata (Pers.: Fr.) Tul. and C. Tul., the causing agent of eutypa dieback, has been increasingly often identified in recent times as a cause of grapevine disease. It was first discovered and identified in Australian vineyards (Carter, 1973), where it represented one of the most dangerous fungus pathogens of this plant. A few years later it was discovered in European vineyards as well. This polyfagous fungus, known originally as E. armeniaca (Honsf. & Carter), was first discovered on apricot, on which it caused the "gummosis disease". In Serbia, Eutypa lata has not been determined officially. However, bearing in mind the form of its spreading (anemochory), as well as the fact that our country is a major producer of grape and fruit, we need to pay special attention to this dangerous pathogen since there are indications that it is already present in our vineyards. During the period between 2003 and 2005, an inspection of a great number of vineyards in the areas of Vršac, Fruška Gora and Kruševac, was conducted. Many of them had grapevines with typical eutypa dieback symptoms. The aim of the inspection was to find grapevines with this disease, to mark them and take samples for laboratory analysis. Marking suspicious grapevines enabled us to monitor the volume of symptoms, as well as other changes on grapevines. Different colors were used for markings, according to the principle "same color - same year" The procedure revealed that the average period between early and mild disease symptoms and extreme changes, including withering of entire vines, was 2 to 3 years. The signs of eutypa dieback on diseased grapevines are manifested: on leaves in the form of chlorosis, twisting, necrosis of the edges, drying out and falling off; on shoots, where the shortening of internodia is noticeable, as well as color change and "zig-zag" distribution of internodes; on blossoms and clusters, where absence of flowering, partial bareness and irregular berry size are observed; and on trunks, where necrosis appears on the cross section in a typical "V" form. These studies also established that there is not a single grapevine plant with symptoms indicating eutypa dieback or a similar disease that is older than 8-10 years. The research results, based on examination and monitoring of disease development in the studied vineyards in previous years, indicate that the fungus Eutypa lata, the inducer of grapevine eutyposis, is most probably present in Serbia, and that our viticulture is facing yet another serious threat. In most European and other viticultural centers, highly specialized research teams are being organized to deal with the phenomenon of eutypa dieback, and its inducer Eutypa lata, which is more and more frequently classified as a top priority disease of wooden tissue, especially considering that the economic losses are very significant and occur in all vineyards, regardless of their location. Therefore, in order to prevent infection and fight the disease successfully, we need to take immediate measures of integral protection of grapevine without any delay.Među prouzrokovače bolesti vinove loze u novije vreme sve češće se ubraja i fitopatogena gljiva Eutypa lata (Pers.: Fr.) Tul. i C. Tul., uzročnik eutipoze. Prvi put je otkrivena i identifikovana u australijskom vinogorju (Carter, 1973), gde predstavlja jednu od najopasnijih mikoza ove biljke. Nekoliko godina kasnije otkrivena je i u vinogorjima Evrope. Ranije je ova polifagna gljiva, pošto je prvi put nađena na kajsiji, bila poznata pod imenom E. armeniaca (Honsf. & Carter), na kojoj prouzrokuje "gumoznu bolest". U Srbiji Eutypa lata još nije zvanično konstatovana. Međutim, imajući u vidu način njenog širenja (anemohorija), kao i činjenicu da je naša zemlja značajan proizvođač grožđa i voća, potrebno je obratiti naročitu pažnju na ovog opasnog patogena, jer ima indicija da je prisutan i u našim vinogorjima. U periodu 2003-2005. godine obavljen je pregled većeg broja vinograda u vršačkom, fruškogorskom i kruševačkom vinogorju. U mnogima od njih nađeni su čokoti sa tipičnim simptomima eutipoze. Cilj ovih ispitivanja bio je pronalaženje ovako obolelih čokota, njihovo obeležavanje, kao i uzimanje uzoraka za dalje laboratorijske analize. Obeležavanje sumnjivih čokota omogućilo nam je da pratimo jačinu izraženosti simptoma, kao i sve ostale promene tih čokota. Za obeležavanje su korišćene različite boje, a primenjen je princip: jedna boja - jedna godina. Ovim postupkom je ustanovljeno da od pojave početnih, blažih simptoma oboljenja, pa do pojave izuzetno izraženih promena, uključujući i izumiranje celih čokota, treba da prođe 2 do 3 godine. Znaci eutipoze na napadnutim čokotima manifestuju se na lišću u vidu hloroze, kovrdžanja, nekroze oboda, sušenja i opadanja listova, na lastarima se uočava skraćivanje internodija, promena boje, "cik-cak" raspored internodusa, na cvastima i grozdovima primetno je izostajanje cvetanja, rehuljavost i neujednačenost veličine bobica, dok se na drvetu javlja nekroza na poprečnom preseku u obliku slova V, tipičnom za ovu bolest. U ovim ispitivanjima je takođe utvrđeno da nema zasada vinove loze starijeg 8-10 godina a da se ne nađu čokoti sa ovakvim simptomima koji upućuju na eutipozu ili slično oboljenje. Rezultati istraživanja dobijeni na osnovu obavljenih pregleda i praćenja razvoja simptoma oboljenja proteklih godina u proučavanim vinogorjima, upućuju na zaključak da je gljiva Eutypa lata, prouzrokovač eutipoze vinove loze, najverovatnije prisutna u Srbiji, i da je naše vinogradarstvo suočeno sa još jednom ozbiljnom opasnošću. U većini evropskih i ostalih vinogradarskih centara organizovani su timovi visokospecijalizovanih stručnjaka koji se bave istraživanjem fenomena eutipoze i njenog prouzrokovača - Eutypa lata, jer se ona sve češće ubraja u najznačajnije bolesti drvenastog tkiva, posebno kada se uzme u obzir da su ekonomski gubici veoma značajni i da se javljaju u svim vinogradima bez obzira na njihovu lokaciju. Zbog toga, a u cilju sprečavanja zaraze, kao i uspešne borbe protiv ove bolesti, neophodno je, bez odlaganja, primeniti mere integralne zaštite vinove loze

Two-Color Dark-Field (TCDF) microscopy for metal nanoparticles imaging inside cells

Noble metal nanoparticles (NPs) supporting localized surface plasmon resonances are widely used in the context of biotechnology as optical and absorption contrast agents with great potential applicability to both diagnostics and less invasive therapies. In this framework, it is crucial to have access to simple and reliable microscopy techniques to monitor the NPs that have internalized into cells. While dark field (DF) microscopy takes advantage of the enhanced NPs scattering at their plasmon resonance, its use in cells is limited by the large scattering background from the internal cell compartments. Here, we report on a novel two-color dark field microscopy that addresses these limitations by significantly reducing the cell scattering contribution. We first present the technique and demonstrate its enhanced contrast, specificity and reliability for NP detection compared to standard optical dark field. We then demonstrate its potential suitability in two different settings, namely wide-field parallel screening of circulating cells in microfluidic chip and high-resolution tracking of internalized NPs in cells. These proof of principle experiments show a promising capability of this approach with possible extension to other kinds of targeted systems like bacteria and vesicles.Peer ReviewedPostprint (author's final draft

Hidden progress: broadband plasmonic invisibility

The key challenge in current research into electromagnetic cloaking is to achieve invisibility over an extended bandwidth. There has been significant progress towards this using the idea of cloaking by sweeping under the carpet of Li and Pendry, with dielectric structures superposed on a mirror. Here, we show that we can harness surface plasmon polaritons at a metal surface structured with a dielectric material to obtain a unique control of their propagation. We exploit this to control plasmonic coupling and demonstrate both theoretically and experimentally cloaking over an unprecedented bandwidth (650-900 nm). Our non-resonant plasmonic metamaterial allows a curved reflector to mimic a flat mirror. Our theoretical predictions are validated by experiments mapping the surface light intensity at the wavelength 800 nm

Gljivična oboljenja drveta vinove loze

Grapevine is constantly exposed to attacks by different agents of biotic and abiotic nature. Some of biotic inducers appear in this old culture every year, in a higher or lower degree, like for example: Plasmopara viticola, inducer of downy mildew, Uncinula necator, inducer of powdery mildew, Botryotinia fuckeliana, inducer of grey decay. Viruses also accompany grapevine frequently, and phytopathogenous bacteria are not so rare. This significantly complicates struggle against them, since although vine often appears healthy, numerous qualitative and quantitative changes occur inside it, which greatly decreases grape yield and quality. Lately, phytoplasma inducers of grapevine tree redness, and yellowness of grapevine leaves, have significantly endangered this culture. Besides, one group of pathogenes, the so called inducers of grapevine tree diseases, attack mostly vines older than 8 years, causing their drying out and withering. The most frequent inducers are: Phomopsis viticola (inducer of grapevine excoriosis), Eutypa lata (inducer of grapevine eutypa dieback), fungi from the gender Botryosphaeria (inducers of grapevine cancer and drying out) and ESCA (a group of fungi causing drying out-apoplexy or black measles of grapevine), which is discussed in detail here. .Vinova loza je konstantno izložena napadu različitih agenasa biotske i abiotske prirode. Neki od biotskih uzročnika javljaju se na ovoj staroj kulturi, u većoj ili manjoj meri svake godine, kao na primer: Plasmopara viticola, prouzrokovač plamenjače, Uncinula necator, prouzrokovač pepelnice, Botryotinia fuckeliana, prouzrokovač sive truleži. Virusi su, takođe, skoro redovni pratioci vinove loze, a nisu retke ni pojedine fitopatogene bakterije. To značajno otežava borbu protiv njih, jer iako je čokot često na izgled zdrav u njemu se dešavaju brojne, kvalitativne i kvantitativne promene, koje u velikoj meri umanjuju prinos i kvalitet grožđa. U poslednje vreme fitoplazme prouzrokovači crvenila drveta i žutila (crvenila) lišća vinove loze značajno ugrožavaju gajenje ove kulture. Pored navedenih, jedna grupa patogena, takozvani prouzrokovači bolesti drveta vinove loze, napadaju uglavnom čokote starosti preko osam godina, uzrokujući njihovo sušenje i propadanje. Najčešći prouzrokovači su: Phomopsis viticola (prouzrokovač ekskorioze vinove loze), Eutypa lata (prouzrokovač eutipoze vinove loze), gljive iz roda Botryosphaeria (prouzrokovači raka i sušenja vinove loze) i ESKA (grupa gljiva prouzrokovača sušenja - apopleksije vinove loze), o kojima će u ovom tekstu biti nešto vise reči.

Eutipoza i ESCA bolesti odumiranja i sušenja čokota vinove loze u Srbiji

For a few years die off and wither symptoms of grapevines are massively present in some grapevine growing regions of Serbia. During 2006 and 2007 in grapevine growing region of Fruška Gora two groups of symptoms, which ultimately lead to dieback, have been documented. On localities Manđelos, Irig and Sremski Karlovci vines with specific bushy appearance have been recorded. The vines had small stunted shoots with short internodes and small cupped leaves. When an infected cordon or trunk is cut in cross-section a V-shaped, brown wedge of dead tissue can be seen (necrosis). After a few years with constant intensifying of growth stunting, vines at last do not develop shoots at all and completely die off. In comparison with authentic symptoms, the presence of dangerous disease determined as Eutypa dieback has been concluded and confirmed. After isolations from the perennial wood, fungus Eutypa lata causer of Eutypa dieback has been identified. Early detection of first recognizable symptoms on shoots has a great significance in Eutypa dieback management and control. On localities Manđelos and Sremski Karlovci, during summer months, massive and progressive withering of normally developed vines has been recorded. In comparison with authentic symptoms, detected presence of bright 'tiger striped' patterns on the leaves, as well as of roundish necrosis in central wood part, confirmed and proved the appearance of very destructive disease known as ESCA disease (or wither). Because of sudden and rapid drying up of whole vines, determination of this disease on the basis of symptoms has a great significance in order to prevent its spreading inside the vineyard, as early as possible. Symptom based determination of Eutypa dieback and ESCA disease has shown successful, but in case of Eutypa dieback special precaution is needed because sometimes similar simptoms can be caused by Botryosphaeria spp. Age structure of vineyards in Serbia is very poor and favorable for Eutypa dieback and ESCA disease appearance. Because of that fact, from year to year these two diseases have increasingly economical significance.Simptomi odumiranja i sušenja čokota vinove loze, već nekoliko godina, pojavljuju se u jakom intenzitetu u nekim vinogorjima Srbije. Tokom 2006. i 2007. godine, u fruškogorskom vinogorju dokumentovane su dve grupe simptoma, čiji je krajnji ishod sušenje čokota. Na lokalitetima Manđelos, Irig i Sremski Karlovci zapaženi su čokoti karakterističnog, žbunastog izgleda, sa malim, zaostalim lastarima sa skraćenim internodijama i sitnim, peharasto uvijenim listovima. Na poprečnom preseku drveta čokota uočene su braon, klinaste, 'V' nekroze. Nakon nekoliko godina sve izraženijeg zaostajanja organa u porastu, čokoti uopšte ne kreću sa vegetacijom i potpuno odumiru. Upoređivanjem sa referentnim simptomima, zaključeno je da se radi o pojavi veoma opasne bolesti drveta, koja je determinisana kao eutipoza vinove loze. Nakon izolacija iz višegodišnjeg drveta, identifikovan je i prouzrokovač Eutypa lata. Rano otkrivanje prvih prepoznatljivih simptoma na lastarima, ima veliki značaj u suzbijanju i kontroli eutipoze. Na lokalitetima Manđelos i Sremski Karlovci zabeleženo je masovno, progresivno sušenje normalno razvijenih čokota tokom letnjih meseci. Nakon upoređivanja sa referentnim simptomima, zabeleženo karakteristično 'tigar' prugasto šarenilo i sušenje lista, kao i kružna nekroza centralnog dela drveta, potvrdili su pojavu veoma destruktivne bolesti, koja je determinisana kao ESCA oboljenje (ili sušenje). Zbog iznenadnog i brzog sušenja celog čokota, determinacija ove bolesti, na osnovu simptoma, ima veliki značaj, kako bi se, što ranije, sprečilo njeno širenje u okviru vinograda. Simptomatološka determinacija eutipoze i ESCA oboljenja pokazala se kao uspešna, s tim da u slučaju eutipoze treba biti posebno oprezan, jer slične simptome ponekad mogu prouzrokovati i Botryosphaeria spp. Loša starosna struktura vinograda u Srbiji pogoduje pojavi eutipoze i ESCA oboljenja, koja, iz godine u godinu, imaju sve veći ekonomski značaj

Unraveling the optomechanical nature of plasmonic trapping

Noninvasive and ultra-accurate optical manipulation of nanometer objects has recently gained interest as a powerful tool in nanotechnology and biophysics. Self-induced back-action (SIBA) trapping in nano-optical cavities has the unique potential for trapping and manipulating nanometer-sized objects under low optical intensities. However, thus far, the existence of the SIBA effect has been shown only indirectly via its enhanced trapping performances. In this article, we present the first time direct experimental evidence of the self-reconfiguration of the optical potential that is experienced by a nanoparticle trapped in a plasmonic nanocavity. Our observations enable us to gain further understanding of the SIBA mechanism and to determine the optimal conditions for boosting the performances of SIBA-based nano-optical tweezers.ISSN:2047-753

Two-Color Dark-Field (TCDF) microscopy for metal nanoparticles imaging inside cells

Noble metal nanoparticles (NPs) supporting localized surface plasmon resonances are widely used in the context of biotechnology as optical and absorption contrast agents with great potential applicability to both diagnostics and less invasive therapies. In this framework, it is crucial to have access to simple and reliable microscopy techniques to monitor the NPs that have internalized into cells. While dark field (DF) microscopy takes advantage of the enhanced NPs scattering at their plasmon resonance, its use in cells is limited by the large scattering background from the internal cell compartments. Here, we report on a novel two-color dark field microscopy that addresses these limitations by significantly reducing the cell scattering contribution. We first present the technique and demonstrate its enhanced contrast, specificity and reliability for NP detection compared to standard optical dark field. We then demonstrate its potential suitability in two different settings, namely wide-field parallel screening of circulating cells in microfluidic chip and high-resolution tracking of internalized NPs in cells. These proof of principle experiments show a promising capability of this approach with possible extension to other kinds of targeted systems like bacteria and vesicles.Peer Reviewe