Procena trofičkog statusa akumulacije očaga (Lazarevac, Srbija) posredstvom Carlsonovog indeksa

Trofički status se može definisati kao ukupna težina živog biološkog materijala (biomase) u nekom vodenom telu na određenom lokalitetu i u određeno vreme. Trofički status nekog vodenog tela može se proceniti na osnovu merenja specifičnih parametara i predstavlja biološki odgovor na spoljašnje faktore, kao što su količina nutrijenata, sezonske promene, ispaša, mešanje vode itd. Procena trofičkog statusa jezera ili akumulacije je od velikog značaja. Postoje različiti kriterijumi za procenu trofičkog stanja jezera, kao što su: koncentracija nutrijenata, produktivnost, kvantitativni i kvalitativni sastav flore i faune, dostupnost kiseonika i morfometrija jezera. Međutim, imajući u vidu da je multiparametarski indeks nepraktičan, Carlson je predložio indekse trofičkog stanja (TSIs) koji su znatno jednostavniji za upotrebu od multiparametarskog indeksa. Ovi indeksi kao bazu za klasifikaciju trofičkih stanja koriste algalnu biomasu. U tom smislu koriste se tri parametra za izračunavanje ovih indeksa: koncentracija hlorofila a, ukupni fosfor i providnost izmerena Secchi diskom. Svaka od ove tri promenljive se može koristiti za klasifikaciju statusa vodenog tela, ali je hlorofila a najznačajniji parametar s obzirom da je direktni pokazatelj algalne biomase. Opseg Carlson-ovog trofičnog indeksa obuhvata vrednosti od 0 do 100. Vrednosti ispod 40 odgovaraju oligotrofnim, od 40 do 50 mezotrofnim, od 50 do 70 eutrofnim, a preko 70 hipereutrofnim jezerima i akumulacijama. Glavna prednost ovog indeksa je što odnos između tri parametra može ukazati na određene uslove koji vladaju u datom jezeru ili akumulaciji, a tiču se faktora koji limitiraju algalnu biomasu ili utiču na izmerene parametre. Iako određivanje trofičkog statusa vode nekog vodenog tela ne treba poistovećivati sa samim kvalitetom vode, ono, svakako, predstavlja značajan aspekt istog. Cilj ovog istraživanja bio je određivanje trofičkog statusa jezera Očaga na osnovu Carlson-ovog trofičnog indeksa i ispitivanje veze između izračunatih indeksa za hlorofil a (TSI(CHL)), ukupni fosfor (TSI(TP)) i providnost merenu Secchi diskom (TSI(SD)). Veštačko jezero Očaga nalazi se u blizini Lazarevca i isključivo se koristi za rekreaciju. Ispitivanje vode rađeno je jednom nedeljno tokom jula i avgusta, od 2012. do 2014. godine. Sve analize urađene su u Zavodu za javno zdravlje iz Beograda. Vrednosti dobijenih indeksa (TSIs) varirale su od 41 do 86.25, u ispitanom periodu, a jezero je menjalo status od mezotrofnog, preko eutrofnog do hipereutrofnog, pri čemu su eutrofni uslovi preovladavali. Hipereutrofija je zabeležena tokom avgusta 2013. Godine, kada su bile izmerene i najveće vrednosti sva tri parametra, što je, verovatno, rezultat organskog opterećenja vodenog ekosistema i vremenskih uslova. Prema podacima RHMZ-a, 2013. godina je bila jedna od najtoplijih i najsušnijih godina još od 1951. godine. Nasuprot tome, u avgustu 2014. godine izmerene su najmanje vrednosti svih parametara, što ukazuje na mezotrofne uslove u jezeru te godine. Mezotrofni status jezera je, verovatno, posledica velike količine padavina u prvoj polovini te godine, ali i pražnjenja i ponovnog punjenja jezera nakon majskih poplava

Plexin-D1/Semaphorin 3E pathway may contribute to dysregulation of vascular tone control and defective angiogenesis in systemic sclerosis

INTRODUCTION: The vascular and nervous systems have several anatomic and molecular mechanism similarities. Emerging evidence suggests that proteins involved in transmitting axonal guidance cues, including members of class III semaphorin (Sema3) family, play a critical role in blood vessel guidance during physiological and pathological vascular development. Sema3E is a natural antiangiogenic molecule that causes filopodial retraction in endothelial cells, inhibiting cell adhesion by disrupting integrin-mediated adhesive structures. The aim of the present study was to investigate whether in systemic sclerosis (SSc) Plexin-D1/Sema3E axis could be involved in the dysregulation of vascular tone control and angiogenesis. METHODS: Sema3E levels were measured by quantitative colorimetric sandwich ELISA in serum samples from 48 SSc patients, 45 subjects with primary Raynaud's phenomenon (pRP) and 48 age-matched and sex-matched healthy controls. Immunofluorescence staining on skin sections from 14 SSc patients and 12 healthy subjects was performed to evaluate Sema3E and Plexin-D1 expression. Western blotting was used to assess Plexin-D1/Sema3E axis in human SSc and healthy dermal microvascular endothelial cells (SSc-MVECs and H-MVECs, respectively) at basal condition and after stimulation with recombinant human vascular endothelial growth factor (VEGF), SSc and healthy sera. Capillary morphogenesis on Matrigel was performed on H-MVECs treated with healthy, pRP or SSc sera in the presence of Sema3E and Plexin-D1 soluble peptides. RESULTS: Serum Sema3E levels were significantly higher both in pRP subjects and SSc patients than in controls. In SSc, Sema3E levels were significantly increased in patients with early nailfold videocapillaroscopy (NVC) pattern compared to active/late patterns and pRP, and in patients without digital ulcers versus those with ulcers. In SSc skin, Sema3E expression was strongly increased in the microvascular endothelium. Cultured SSc-MVECs showed higher levels of phosphorylated Plexin-D1 and Sema3E expression than H-MVECs, and stimulation with SSc sera increased phosphorylated Plexin-D1 and Sema3E in H-MVECs. The addition of Sema3E-binding Plexin-D1 soluble peptide significantly attenuated the antiangiogenic effect of SSc sera on H-MVECs. CONCLUSIONS: Our findings suggest that Plexin-D1/Sema3E axis is triggered in SSc endothelium and may have a role in the dysregulation of angiogenesis and vascular tone control by inducing neuro-vascular mechanism alterations clinically evident in particular in the early disease phases

Proangiogenic effects of soluble α-Klotho on systemic sclerosis dermal microvascular endothelial cells

BACKGROUND: Systemic sclerosis (SSc) is characterized by endothelial cell (EC) apoptosis, impaired angiogenesis and peripheral microvasculopathy. Soluble α-Klotho (sKl) is a pleiotropic molecule with multiple effects on ECs, including antioxidant and vasculoprotective activities. On the EC surface, sKl interacts with vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2) and transient receptor potential canonical-1 (TRPC-1) cation channel to control EC homeostasis. Here, we investigated whether sKl might act as a protective factor to improve angiogenesis in dermal microvascular endothelial cells (MVECs) from SSc patients (SSc-MVECs). METHODS: Wound healing assay was performed on healthy dermal MVECs (H-MVECs) challenged with sera from healthy controls or SSc patients with or without the addition of sKl. Capillary morphogenesis on Matrigel was assessed in H-MVECs and SSc-MVECs at basal conditions and treated with sKl, as well as in H-MVECs challenged with healthy or SSc sera in presence or absence of sKl. The expression of α-Klotho, VEGF(165)b, VEGFR-2, TRPC-1, Ki67 and active caspase-3 in H-MVECs and SSc-MVECs was investigated by western blotting. Immunostaining for α-Klotho was performed in H-MVECs and SSc-MVECs, and in healthy and SSc skin sections. RESULTS: Treatment with sKl effectively counteracted the inihibitory effects of SSc sera on wound healing ability and angiogenic performance of H-MVECs. The addition of sKl significantly improved angiogenesis and maintained over time capillary-like tube formation in vitro by SSc-MVECs. Stimulation of SSc-MVECs with sKl resulted in the upregulation of the proliferation marker Ki67 in parallel with the downregulation of proapoptotic active caspase-3. The expression of α-Klotho was significantly lower in SSc-MVECs than in H-MVECs. The expression of TRPC-1 was also significantly decreased, while that of VEGFR-2 and VEGF(165)b was significantly increased, in SSc-MVECs compared with H-MVECs. Challenge with sKl either significantly increased TRPC-1 or decreased VEGF(165)b in SSc-MVECs. Ex vivo analyses revealed that α-Klotho immunostaining was almost absent in the dermal microvascular network of SSc skin compared with control skin. CONCLUSIONS: Our findings provide the first evidence that α-Klotho is significantly decreased in the microvasculature in SSc skin and that sKl administration may effectively improve SSc-MVEC functions in vitro by acting as a powerful proangiogenic factor

The effect of meteorological and chemical parameters on summer phytoplankton assemblages in an urban recreational lake

The summer phytoplankton community was studied across both vertical and temporal scales in relation to environmental factors in the shallowrecreational Sava Lake. The sampling was conducted weekly at four depths from mid-July until mid-September 2014, in order to detect short-term changes within the assemblages. Besides physical and chemical parameters, meteorological data was also included in the investigation, as that year was characterized with extreme rainfall, which caused serious flooding in the region. The community succession was characterized by a reverse in the cyanobacteria (Codon M) and chlorococcal green algae (Coda F and J). Statistical analyses (RDA) indicated that changes in the community composition and successional pattern could have been due to the mixing regime variations in the reservoir, most likely induced by weather disturbances, especially high precipitation and wind events. These events did not permit massive cyanobacterial development, although they most likely caused resuspension of dissolved phosphorus from the sediment. When observing functional groups, three groups could be distinguished by their response to the above-mentioned parameters: the first prefers high temperature and insolation(Lm, Y, Lo, Xph, W2andM), the second is correlated with precipitation and wind (Td, C, K, MP and X2), while the third group tolerates cloudiness (H1, F, N, X1, D, J and P)

PESFOR-W: Improving the design and environmental effectiveness of woodlands for water Payments for Ecosystem Services

ABSTRACT: The EU Water Framework Directive aims to ensure restoration of Europe?s water bodies to ?good ecological status? by 2027. Many Member States will struggle to meet this target, with around half of EU river catchments currently reporting below standard water quality. Diffuse pollution from agriculture represents a major pressure, affecting over 90% of river basins. Accumulating evidence shows that recent improvements to agricultural practices are benefiting water quality but in many cases will be insufficient to achieve WFD objectives. There is growing support for land use change to help bridge the gap, with a particular focus on targeted tree planting to intercept and reduce the delivery of diffuse pollutants to water. This form of integrated catchment management offers multiple benefits to society but a significant cost to landowners and managers. New economic instruments, in combination with spatial targeting, need to be developed to ensure cost effective solutions - including tree planting for water benefits - are realised. Payments for Ecosystem Services (PES) are flexible, incentive-based mechanisms that could play an important role in promoting land use change to deliver water quality targets. The PESFOR-W COST Action will consolidate learning from existing woodlands for water PES schemes in Europe and help standardize approaches to evaluating the environmental effectiveness and cost-effectiveness of woodland measures. It will also create a European network through which PES schemes can be facilitated, extended and improved, for example by incorporating other ecosystem services linking with aims of the wider forestscarbon policy nexus