Influence of Matrix Metalloproteinases MMP-2, -3 and on Age- Related Macular Degeneration Development

Age-related macular degeneration (AMD) is the leading cause of significant and irreversible central visual loss as it affects a small area of the retina, called the macula. However, the pathogenesis of still fairly understood. AMD has a multifactorial etiology, and its development might be influenced by body peculiarities, environmental and genetic factors. Risk factors such as age, gender, cigarette smoking, color of iris, nutrition, body mass index, oxidative stress, and genetic factors (complement factor H gene, Apo E gene, matrix metalloproteinases (MMPs) genes and others) increase probability to develop AMD. Here, we discuss about choroidal neovascularization process, where hypoxia, inflammatory process, and proteolytic enzymes play a main role, but mainly we focus on the family of matrix metalloproteinases (MMPs), especially on MMP -2, -3 and -9, and their impact on AMD development. MMPs belong to a family of proteolytic zinc-containing enzymes, and their mechanism under normal physiological conditions is precisely regulated, but when is dysregulated, MMPs become a cause of various diseases, including and AMD. MMPs are capable of degrading most of the extracellular matrix components, which are important in the remodeling during angiogenesis. Angiogenesis is the main pathological process associated with age-related macular degeneration development. Activated endothelial cells release MMPs which by degrading the basilar membrane allows capillaries to grow beneath the retina and retinal layers. Such capillaries often bleed, more liquids are filtered through the walls, and fibrous tissue grows within. Furthermore, swelling of the retina and impaired vision occur. In this book chapter, we focus on AMD prevalence, risk factors, clinics, diagnostics and influence of MMP-2, -3 and -9 on AMD development

Impacts of low-head hydropower plants on cyprinid-dominated fish assemblages in Lithuanian rivers

The meso-scale habitat simulation model MesoHABSIM was applied in three Lithuanian lowland rivers to study the effect of low-head hydropower plants (HPPs) on the fish habitats. Stream flow time series on a daily scale for the period 1970–2015 were used to describe flow regime downstream of HPPs for periods before and after their installation. Conditional habitat suitability criteria were developed for 4 species of cyprinid fish, schneider (Alburnoides bipunctatus), dace (Leuciscus leuciscus), roach (Rutilus rutilus) and vimba (Vimba vimba) to simulate their available habitat at different water discharges. Modelling results showed that HPPs have a significant impact on habitat availability in the low flow period in dry years below HPPs due to insufficient released flow. The environmental flow, as prescribed by the Lithuanian national law, is estimated between 80 and 95% exceedance probability of the mean minimum discharge of 30 days. This flow leads to a significant reduction in frequency and duration of available suitable habitats for vimba and schneider during low flow period. The roach habitat is the least affected. The results of habitat modelling are in line with the actual data on the occurrence and relative abundance of considered fish species in the studied river stretches. A general comparison of the relative abundance of modelled fish species in 42 natural river stretches and 20 stretches below the HPPs also showed that the relative abundance of roach is significantly higher, and that of schneider is significantly lower in river sections below the HPPs than the abundance in natural river sections. All results indicate that the current environmental flow does not secure survival of certain fish species. The applicability of the average low flow release during summer could be a plausible alternative to the current environmental flow in order to maintain ecosystem health and services

The impact of five long-term contrasting tillage systems on maize productivity parameters

Maize productivity is mainly constrained by the climate, meteorological and soil conditions, and agro-technological practice. Reduced primary tillage intensity might be a method to optimize the complex interactions between these conditions. An 8-year field experiment was designed to test this. The aim of the experiment was to establish the influence of deep and shallow ploughing, chiselling, disking and no-tillage systems on parameters of maize productivity. No-tillage resulted in a significant decrease in maize stand density compared with deep and shallow ploughing, as well as chiselling, while maize canopy height and dry biomass was slightly higher in the no-tillage system. Nevertheless, in no-tillage plots the maize yield was insignificantly lower than in deeply and shallowly ploughed plots (on average 3.5–6.4% less). Overall, long-term reduction of primary tillage had less impact on maize productivity parameters than meteorological conditions during the vegetation period

Flood pattern changes in the rivers of the Baltic countries

Estimation of both the frequency and variation of spring floods is a key issue for the assessment and management of flood risks. Changes in river floods in Estonia, Latvia and Lithuania have been investigated in few national studies. However, there are no studies of the changes of flood patterns by using a common methodology for the rivers of this region. In this study flood pattern changes in the rivers of the Baltic countries were estimated applying trend and frequency analysis for the periods of 1922–2010, 1922–1960, 1961–2010 and 1991–2010, i.e. for the whole spring flood data sets, periods before and after 1960 (this year was considered as the beginning of the remarkable climate change), as well as for the two past decades. A comparative study of five probability distributions was performed in order to estimate which distribution at best represents statistical characteristics of the flood data. The results showed that maximum discharges of spring floods decreased over the whole studied period. Only some insignificant positive trends of maximum discharges were found in the last time period in continental and transitional rivers. Generalized extreme value distribution provided the best approximation to the maximum discharge data series of the rivers of Baltic countries for the whole observation period. First published online: 08 Jul 201

The combined impact of hydropower plants and climate change on river runoff and fish habitats in lowland watersheds

Aquatic ecosystems are particularly vulnerable to anthropogenic activity and climate change. The changes in flow regimes in Lithuanian lowland rivers due to the operation of hydropower plants (HPPs) and the impact of altered flow on some fish species have already been studied. The impact of climate change on future natural river runoff and the structure of fish assemblages was also investigated. However, it is still unknown how the combined effect of climate change and flow regulation related to hydropower generation may affect fish assemblages in the downstream river reaches below the Lithuanian HPPs. In this study, the physical habitat modelling system MesoHABSIM was used to simulate spatial and temporal changes in aquatic habitats availability for different fish species under the influence of HPP at different climate change scenarios. Changes in the available habitat were assessed for common fish species in four HPP-affected rivers representing different hydrological regions of Lithuania. The modelling results showed that the operation of HPP under climate change conditions in most rivers could be beneficial for small benthic fish species such as gudgeon Gobio gobio and stone loach Barbatula barbatula. Meanwhile, for larger fish species (e.g., chub Squalius cephalus and vimba Vimba vimba) the alteration in the temporal availability of suitable habitat was relatively higher

Allelopathic effect of organic mulches on vegetable germination and early development

Plants, as well as their residues (mulches), release physiologically active substances (allelochemicals), which may affect plant germination, development, and productivity. In this study we investigated the allelopathic effects of aqueous extracts of organic mulches (winter wheat straw, peat, sawdust, and gramineous grass) at different concentrations on germination and early growth of radish (Raphanus sativus L.), carrot (Daucus sativus Rohl.), and lettuce (Lactuca sativa L.). It was found, that the strongest negative effect on the germination and shoot and root development of investigated vegetables was with the highest concentration (1 : 10) of the grass aqueous extract. Peat mulch aqueous extracts had the least negative impact on all vegetable seed germination. Straw and peat mulches stimulated the early growth of R. sativus shoots, but there was a negative affect on D. sativus shoot development. The aqueous extracts of various organic mulches had negative effects on R. sativus, while mostly positive effects found on L. sativa root development

Identification of coherent flood regions across Europe by using the longest streamflow records

This study compiles a new dataset, consisting of the longest available flow series from across Europe, and uses it to study the spatial and temporal clustering of flood events across the continent. Hydrological series at 102 gauging stations were collected from 25 European countries. Five geographically distinct large-scale homogeneous regions are identified: (i) an Atlantic region, (ii) a Continental region, (iii) a Scandinavian region, (iv) an Alpine region, and (v) a Mediterranean region. The months with a higher likelihood of flooding were identified in each region. The analysis of the clustering of annual counts of floods revealed an over-dispersion in the Atlantic and Continental regions, forming flood-rich and flood-poor periods, as well as an under-dispersion in the Scandinavian region that points to a regular pattern of flood occurrences at the inter-annual scale. The detection of trends in flood series is attempted by basing it on the identified regions, interpreting the results at a regional scale and for various time periods: 1900-1999; 1920-1999; 1939-1998 and 1956-1995. The results indicate that a decreasing trend in the magnitude of floods was observed mainly in the Continental region in the period 1920-1999 with 22% of the catchments revealing such a trend, as well as a decreasing trend in the timing of floods in the Alpine region in the period 1900-1999 with 75% of the catchments revealing this trend. A mixed pattern of changes in the frequency of floods over a threshold and few significant changes in the timing of floods were detected

Simulating long-term carbon nitrogen and phosphorus biogeochemical cycling in agricultural environments

Understanding how agricultural practices alter biogeochemical cycles is vital for maintaining land productivity, food security, and other ecosystem services such as carbon sequestration. However, these are complex, highly coupled long-term processes that are difficult to observe or explore through empirical science alone. Models are required that capture the main anthropogenic disturbances, whilst operating across regions and long timescales, simulating both natural and agricultural environments, and shifts among these. Many biogeochemical models neglect agriculture or interactions between carbon and nutrient cycles, which is surprising given the scale of intervention in nitrogen and phosphorus cycles introduced by agriculture. This gap is addressed here, using a plant-soil model that simulates integrated soil carbon, nitrogen and phosphorus (CNP) cycling across natural, semi-natural and agricultural environments. The model is rigorously tested both spatially and temporally using data from long-term agricultural experiments across temperate environments. The model proved capable of reproducing the magnitude of and trends in soil nutrient stocks, and yield responses to nutrient addition. The model has potential to simulate anthropogenic effects on biogeochemical cycles across northern Europe, for long timescales (centuries) without site-specific calibration, using easily accessible input data. The results demonstrate that weatherable P from parent material has a considerable effect on modern pools of soil C and N, despite significant perturbation of nutrient cycling from agricultural practices, highlighting the need to integrate both geological and agricultural processes to understand effects of land-use change on food security, C storage and nutrient sustainability. The results suggest that an important process or source of P is currently missing in our understanding of agricultural biogeochemical cycles. The model could not explain how yields were sustained in plots with low P fertiliser addition. We suggest that plant access to organic P is a key uncertainty warranting further research, particularly given sustainability concerns surrounding rock sources of P fertiliser

Carbon inputs from Miscanthus displace older soil organic carbon without inducing priming

The carbon (C) dynamics of a bioenergy system are key to correctly defining its viability as a sustainable alternative to conventional fossil fuel energy sources. Recent studies have quantified the greenhouse gas mitigation potential of these bioenergy crops, often concluding that C sequestration in soils plays a primary role in offsetting emissions through energy generation. Miscanthus is a particularly promising bioenergy crop and research has shown that soil C stocks can increase by more than 2 t C ha−1 yr−1. In this study, we use a stable isotope (13C) technique to trace the inputs and outputs from soils below a commercial Miscanthus plantation in Lincolnshire, UK, over the first 7 years of growth after conversion from a conventional arable crop. Results suggest that an unchanging total topsoil (0–30 cm) C stock is caused by Miscanthus additions displacing older soil organic matter. Further, using a comparison between bare soil plots (no new Miscanthus inputs) and undisturbed Miscanthus controls, soil respiration was seen to be unaffected through priming by fresh inputs or rhizosphere. The temperature sensitivity of old soil C was also seen to be very similar with and without the presence of live root biomass. Total soil respiration from control plots was dominated by Miscanthus-derived emissions with autotrophic respiration alone accounting for ∼50 % of CO2. Although total soil C stocks did not change significantly over time, the Miscanthus-derived soil C accumulated at a rate of 860 kg C ha−1 yr−1 over the top 30 cm. Ultimately, the results from this study indicate that soil C stocks below Miscanthus plantations do not necessarily increase during the first 7 years