Browsing by Subject "INCREASES"

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  • Posti, Jussi P.; Takala, Riikka S. K.; Raj, Rahul; Luoto, Teemu M.; Azurmendi, Leire; Lagerstedt, Linnea; Mohammadian, Mehrbod; Hossain, Iftakher; Gill, Jessica; Frantzen, Janek; van Gils, Mark; Hutchinson, Peter J.; Katila, Ari J.; Koivikko, Pia; Maanpää, Henna-Riikka; Menon, David K.; Newcombe, Virginia F.; Tallus, Jussi; Blennow, Kaj; Tenovuo, Olli; Zetterberg, Henrik; Sanchez, Jean-Charles (2020)
    Background: Blood biomarkers may enhance outcome prediction performance of head computed tomography scores in traumatic brain injury (TBI). Objective: To investigate whether admission levels of eight different protein biomarkers can improve the outcome prediction performance of the Helsinki computed tomography score (HCTS) without clinical covariates in TBI. Materials and methods: Eighty-two patients with computed tomography positive TBIs were included in this study. Plasma levels of beta-amyloid isoforms 1-40 (A beta 40) and 1-42 (A beta 42), glial fibrillary acidic protein, heart fatty acid-binding protein, interleukin 10 (IL-10), neurofilament light, S100 calcium-binding protein B, and total tau were measured within 24 h from admission. The patients were divided into favorable (Glasgow Outcome Scale-Extended 5-8, n = 49) and unfavorable (Glasgow Outcome Scale-Extended 1-4, n = 33) groups. The outcome was assessed 6-12 months after injury. An optimal predictive panel was investigated with the sensitivity set at 90-100%. Results: The HCTS alone yielded a sensitivity of 97.0% (95% CI: 90.9-100) and specificity of 22.4% (95% CI: 10.2-32.7) and partial area under the curve of the receiver operating characteristic of 2.5% (95% CI: 1.1-4.7), in discriminating patients with favorable and unfavorable outcomes. The threshold to detect a patient with unfavorable outcome was an HCTS > 1. The three best individually performing biomarkers in outcome prediction were A beta 40, A beta 42, and neurofilament light. The optimal panel included IL-10, A beta 40, and the HCTS reaching a partial area under the curve of the receiver operating characteristic of 3.4% (95% CI: 1.7-6.2) with a sensitivity of 90.9% (95% CI: 81.8-100) and specificity of 59.2% (95% CI: 40.8-69.4). Conclusion: Admission plasma levels of IL-10 and A beta 40 significantly improve the prognostication ability of the HCTS after TBI.
  • Grotell, Milo; den Hollander, Bjornar; Jalkanen, Aaro; Törrönen, Essi; Ihalainen, Jouni; de Miguel, Elena; Dudek, Mateusz; Kettunen, Mikko I.; Hyytiä, Petri; Forsberg, Markus M.; Kankuri, Esko; Korpi, Esa R. (2021)
    Mephedrone (4-MMC), despite its illegal status, is still a widely used psychoactive substance. Its effects closely mimic those of the classical stimulant drug methamphetamine (METH). Recent research suggests that unlike METH, 4-MMC is not neurotoxic on its own. However, the neurotoxic effects of 4-MMC may be precipitated under certain circumstances, such as administration at high ambient temperatures. Common use of 4-MMC in conjunction with alcohol raises the question whether this co-consumption could also precipitate neurotoxicity. A total of six groups of adolescent rats were treated twice daily for four consecutive days with vehicle, METH (5 mg/kg) or 4-MMC (30 mg/kg), with or without ethanol (1.5 g/kg). To investigate persistent delayed effects of the administrations at two weeks after the final treatments, manganese-enhanced magnetic resonance imaging brain scans were performed. Following the scans, brains were collected for Golgi staining and spine analysis. 4-MMC alone had only subtle effects on neuronal activity. When administered with ethanol, it produced a widespread pattern of deactivation, similar to what was seen with METH-treated rats. These effects were most profound in brain regions which are known to have high dopamine and serotonin activities including hippocampus, nucleus accumbens and caudate-putamen. In the regions showing the strongest activation changes, no morphological changes were observed in spine analysis. By itself 4-MMC showed few long-term effects. However, when co-administered with ethanol, the apparent functional adaptations were profound and comparable to those of neurotoxic METH.
  • Mäkeläinen, Sanna; Harlio, Annika; Heikkinen, Risto K.; Herzon, Irina; Kuussaari, Mikko; Lepikkö, Katri; Maier, Andrea; Seimola, Tuomas; Tiainen, Juha; Arponen, Anni (2019)
  • Hällfors, Maria H.; Pöyry, Juha; Heliölä, Janne; Kohonen, Ilmari; Kuussaari, Mikko; Leinonen, Reima; Schmucki, Reto; Sihvonen, Pasi; Saastamoinen, Marjo (2021)
    Species can adapt to climate change by adjusting in situ or by dispersing to new areas, and these strategies may complement or enhance each other. Here, we investigate temporal shifts in phenology and spatial shifts in northern range boundaries for 289 Lepidoptera species by using long-term data sampled over two decades. While 40% of the species neither advanced phenology nor moved northward, nearly half (45%) used one of the two strategies. The strongest positive population trends were observed for the minority of species (15%) that both advanced flight phenology and shifted their northern range boundaries northward. We show that, for boreal Lepidoptera, a combination of phenology and range shifts is the most viable strategy under a changing climate. Effectively, this may divide species into winners and losers based on their propensity to capitalize on this combination, with potentially large consequences on future community composition.
  • Leino, Sakari; Kohtala, Samuel; Rantamäki, Tomi; Koski, Sini K.; Rannanpää, Saara; Salminen, Outi (2018)
    BackgroundThe treatment of Parkinson's disease is often complicated by levodopa-induced dyskinesia (LID). Nicotinic acetylcholine receptor agonists can alleviate LID in animal models but may be less effective in conditions of severe dopaminergic denervation. While the mechanisms of LID remain incompletely understood, elevated corticostriatal levels of the brain-derived neurotrophic factor (BDNF) have been suggested to play a role. Here, female mice with near-total unilateral 6-hydroxydopamine-induced nigrostriatal lesions were chronically treated with levodopa, and the effects of the 7 nicotinic receptor partial agonist AZD0328 and nicotine on LID were assessed. At the end of the experiment, BDNF protein levels in the prefrontal cortex and striatum were measured.ResultsFive-day treatments with three escalating doses of AZD0328 and a 10-week treatment with nicotine failed to alleviate LID. BDNF levels in the lesioned striatum correlated positively with LID severity, but no evidence was found for a levodopa-induced elevation of corticostriatal BDNF in the lesioned hemisphere. The nicotine treatment decreased BDNF levels in the prefrontal cortex but had no effect on striatal BDNF.ConclusionsThe findings suggest that treatment of LID with nicotinic agonists may lose its effectiveness as the disease progresses, represent further evidence for a role for BDNF in LID, and expand previous knowledge on the effects of long-term nicotine treatment on BDNF.
  • Yohannes, Dawit A.; de Kauwe, Andrea; Kaukinen, Katri; Kurppa, Kalle; Mäki, Markku; Anderson, Robert P.; Linnarsson, Sten; Greco, Dario; Saavalainen, Päivi (2020)
    The pathological mechanisms that lead to the onset and reactivation of celiac disease (CD) remain largely unknown. While gluten free diet (GFD) improves the intestinal damage and associated clinical symptoms in majority of cases, it falls short of providing full recovery. Additionally, late or misdiagnosis is also common as CD presents with a wide range of symptoms. Clear understanding of CD pathogenesis is thus critical to address both diagnostic and treatment concerns. We aimed to study the molecular impact of short gluten exposure in GFD treated CD patients, as well as identify biological pathways that remain altered constitutively in CD regardless of treatment. Using RNAseq profiling of PBMC samples collected from treated CD patients and gluten challenged patient and healthy controls, we explored the peripheral transcriptome in CD patients following a short gluten exposure. Short gluten exposure of just three days was enough to alter the genome-wide PBMC transcriptome of patients. Pathway analysis revealed gluten-induced upregulation of mainly immune response related pathways, both innate and adaptive, in CD patients. We evaluated the perturbation of biological pathways in sample-specific manner. Compared to gluten exposed healthy controls, pathways related to tight junction, olfactory transduction, metabolism of unsaturated fatty acids (such as arachidonic acid), metabolism of amino acids (such as cysteine and glutamate), and microbial infection were constitutively altered in CD patients regardless of treatment, while GFD treatment appears to mostly normalize immune response pathways to "healthy" state. Upstream regulator prediction analysis using differentially expressed genes identified constitutively activated regulators relatively proximal to previously reported CD associated loci, particularly SMARCA4 on 19p13.2 and CSF2 on 5q31. We also found constitutively upregulated genes in CD that are in CD associated genetic loci such as MEF2BNB-MEF2B (BORCS8-MEF2B) on 19p13.11 and CSTB on 21q22.3. RNAseq revealed strong effects of short oral gluten challenge on whole PBMC fraction and constitutively altered pathways in CD PBMC suggesting important factors other than gluten in CD pathogenesis.
  • Zhu, Duolong; Fu, Yuxin; Liu, Fulu; Xu, Haijin; Saris, Per Erik Joakim; Qiao, Mingqiang (2017)
    Background: The implementation of novel chassis organisms to be used as microbial cell factories in industrial applications is an intensive research field. Lactococcus lactis, which is one of the most extensively studied model organisms, exhibits superior ability to be used as engineered host for fermentation of desirable products. However, few studies have reported about genome reduction of L. lactis as a clean background for functional genomic studies and a model chassis for desirable product fermentation. Results: Four large nonessential DNA regions accounting for 2.83% in L. lactis NZ9000 (L. lactis 9 k) genome (2,530,294 bp) were deleted using the Cre-loxP deletion system as the first steps toward a minimized genome in this study. The mutants were compared with the parental strain in several physiological traits and evaluated as microbial cell factories for heterologous protein production (intracellular and secretory expression) with the red fluorescent protein (RFP) and the bacteriocin leucocin C (LecC) as reporters. The four mutants grew faster, yielded enhanced biomass, achieved increased adenosine triphosphate content, and diminished maintenance demands compared with the wild strain in the two media tested. In particular, L. lactis 9 k-4 with the largest deletion was identified as the optimum candidate host for recombinant protein production. With nisin induction, not only the transcriptional efficiency but also the production levels of the expressed reporters were approximately three-to fourfold improved compared with the wild strain. The expression of lecC gene controlled with strong constitutive promoters P5 and P8 in L. lactis 9 k-4 was also improved significantly. Conclusions: The genome-streamlined L. lactis 9 k-4 outcompeted the parental strain in several physiological traits assessed. Moreover, L. lactis 9 k-4 exhibited good properties as platform organism for protein production. In future works, the genome of L. lactis will be maximally reduced by using our specific design to provide an even more clean background for functional genomics studies than L. lactis 9 k-4 constructed in this study. Furthermore, an improved background will be potentially available for use in biotechology.
  • Herczeg, Gabor; Gonda, Maria Abigel; Balazs, Gergely; Noreikiene, Kristina; Merila, Juha (2015)
    Background: Plasticity in brain size and the size of different brain regions during early ontogeny is known from many vertebrate taxa, but less is known about plasticity in the brains of adults. In contrast to mammals and birds, most parts of a fish's brain continue to undergo neurogenesis throughout adulthood, making lifelong plasticity in brain size possible. We tested whether maturing adult three-spined sticklebacks (Gasterosteus aculeatus) reared in a stimulus-poor environment exhibited brain plasticity in response to environmental enrichment, and whether these responses were sex-specific, thus altering the degree of sexual size dimorphism in the brain. Results: Relative sizes of total brain and bulbus olfactorius showed sex-specific responses to treatment: males developed larger brains but smaller bulbi olfactorii than females in the enriched treatment. Hence, the degree of sexual size dimorphism (SSD) in relative brain size and the relative size of the bulbus olfactorius was found to be environment-dependent. Furthermore, the enriched treatment induced development of smaller tecta optica in both sexes. Conclusions: These results demonstrate that adult fish can alter the size of their brain (or brain regions) in response to environmental stimuli, and these responses can be sex-specific. Hence, the degree of SSD in brain size can be environment-dependent, and our results hint at the possibility of a large plastic component to SSD in stickleback brains. Apart from contributing to our understanding of the processes shaping and explaining variation in brain size and the size of different brain regions in the wild, the results show that provision of structural complexity in captive environments can influence brain development. Assuming that the observed plasticity influences fish behaviour, these findings may also have relevance for fish stocking, both for economical and conservational purposes.
  • Lönnqvist, Jan-Erik; Walkowitz, Gari (2019)
    In a monetarily incentivized Dictator Game, we expected Dictators' empathy toward the Recipients to cause more pro-social allocations. Empathy was experimentally induced via a commonly used perspective taking task. Dictators (N = 474) were instructed to split an endowment of 10(sic) between themselves and an unknown Recipient. They could split the money 8/2 (8(sic) for Dictator, 2(sic) for Recipient) or 5/5 (5(sic) each). Although the empathy manipulation successfully increased Dictators' feelings of empathy toward the Recipients, Dictators' decisions on how to split the money were not affected. We had ample statistical power (above 0.99) to detect a typical social psychology effect (corresponding to r around 0.20). Other possible determinants of generosity in the Dictator Game should be investigated.
  • Pitkänen, Hanna; Jouppila, Annukka; Lemponen, Marja; Ilmakunnas, Minna; Ahonen, Jouni; Lassila, Riitta (2017)
    Introduction: Factor XIII (FXIII) cross-links fibrin, completing blood coagulation. Congenital FXIII deficiency is managed with plasma-derived FXIII (pdFXIII) or recombinant FXIII (rFXIII) concentrates. Aim: As the mechanisms protecting patients with low FXIII levels ( Methods: Patients received initially rFXIII (35 IU/kg, A-subunit) following with pdFXIII at 1250 IU or 2500 IU (1230 IU/kg) monthly. TG (CAT), thromboelastometry (ROTEM), prothrombin fragments F1 + 2, fibrinogen and FXIII activity (FXIII:C) were measured at baseline and one-hour recovery. Results: FXIII was at the target level of 20 +/- 6 IU/dL at the 4-week trough. rFXIII corrected FXIII to 98 +/- 15 and high-dose pdFXIII to a level of 90 +/- 6, whereas low-dose/half dose pdFXIII reached 45 +/- 4 IU/dL. Although fibrinogen (Clauss Method) was normal, coagulation in FIBTEM was impaired, which FXIII administration tended to correct. CAT implied 1.6- to 1.9-fold enhanced TG, which FXIII administration normalized. Inhibition of fibrin polymerization by Gly-Pro-Arg-Pro peptide mimicked FXIII deficiency in CAT by enhancing TG both in control and FXIII recovery plasma. Antithrombin, alpha 2-macroblobulin-thrombin complex and prothrombin were normal, whereas F1 + 2 were elevated compatible with in vivo TG. Discussion: FXIII deficiency impairs fibrinogen function and fibrin formation simultaneously enhancing TG on the poorly polymerizing fibrin strands, when fibrin's antithrombin I -like function is absent. Our study suggests an inverse link between low FXIII levels and enhanced TG modifying structure-function relationship of fibrin to support hemostasis. (C) 2016 Elsevier Ltd. All rights reserved.
  • Tomasic, Nikica; Kotarsky, Heike; Figueiredo, Rejane de Oliveira; Hansson, Eva; Mörgelin, Matthias; Tomasic, Ivan; Kallijärvi, Jukka; Elmer, Eskil; Jauhiainen, Matti; Eklund, Erik A.; Fellman, Vineta (2020)
    Mice homozygous for the human GRACILE syndrome mutation (Bcs1l (c.A232G)) display decreased respiratory chain complex III activity, liver dysfunction, hypoglycemia, rapid loss of white adipose tissue and early death. To assess the underlying mechanism of the lipodystrophy in homozygous mice (Bcs1l(p.S)(78G)), these and wild-type control mice were subjected to a short 4-hour fast. The homozygotes had low baseline blood glucose values, but a similar decrease in response to fasting as in wild-type mice, resulting in hypoglycemia in the majority. Despite the already depleted glycogen and increased triacylglycerol content in the mutant livers, the mice responded to fasting by further depletion and increase, respectively. Increased plasma free fatty acids (FAs) upon fasting suggested normal capacity for mobilization of lipids from white adipose tissue into circulation. Strikingly, however, serum glycerol concentration was not increased concomitantly with free FM, suggesting its rapid uptake into the liver and utilization for fuel or gluconeogenesis in the mutants. The mutant hepatocyte mitochondria were capable of responding to fasting by appropriate morphological changes, as analyzed by electron microscopy, and by increasing respiration. Mutants showed increased hepatic gene expression of major metabolic controllers typically associated with fasting response (Ppargc1a, Fgf21, Cd36) already in the fed state, suggesting a chronic starvation-like metabolic condition. Despite this, the mutant mice responded largely normally to fasting by increasing hepatic respiration and switching to FA utilization, indicating that the mechanisms driving these adaptations are not compromised by the CIII dysfunction. Summary statement: Bcs1l mutant mice with severe CIII deficiency, energy deprivation and post-weaning lipolysis respond to fasting similarly to wild-type mice, suggesting largely normal systemic lipid mobilization and utilization mechanisms.
  • Ma, Hongbing; Zheng, Shuyu; Zhang, Xiaozhi; Gong, Tuotuo; Lv, Xin; Fu, Shenbo; Zhang, Shuqun; Yin, Xiaoran; Hao, Jingcan; Shan, Changyou; Huang, Shan (2019)
    Resistance to radiotherapy results in relapse and treatment failure in locally advanced esophageal squamous cell carcinoma (ESCC). High mobility group box 1 (HMGB1) is reported to be associated with the radioresistance in bladder and breast cancer. However, the role of HMGB1 in the radiotherapy response in ESCC has not been fully elucidated. Here, we investigated the role of HMGB1 to radioresistance in ESCC clinical samples and cell lines. We found that HMGB1 expression was associated with tumor recurrence after postoperative radiotherapy in locally advanced ESCC patients. HMGB1 knockdown in ESCC cells resulted in increased radiosensitivity both in vitro and in vivo. Autophagy level was found depressed in HMGB1 inhibition cells and activation of autophagy brought back cell's radioresistance. Our results demonstrate that HMGB1 activate autophagy and consequently promote radioresistance. HMGB1 may be used as a predictor of poor response to radiotherapy in ESCC patients. Our finding also highlights the importance of the utility of HMGB1 in ESCC radiosensitization.
  • Mammola, Stefano; Fontaneto, Diego; Martinez, Alejandro; Chichorro, Filipe (2021)
    Many believe that the quality of a scientific publication is as good as the science it cites. However, quantifications of how features of reference lists affect citations remain sparse. We examined seven numerical characteristics of reference lists of 50,878 research articles published in 17 ecological journals between 1997 and 2017. Over this period, significant changes occurred in reference lists' features. On average, more recent papers have longer reference lists and cite more high Impact Factor papers and fewer non-journal publications. We also show that highly cited articles across the ecological literature have longer reference lists, cite more recent and impactful references, and include more self-citations. Conversely, the proportion of 'classic' papers and non-journal publications cited, as well as the temporal span of the reference list, have no significant influence on articles' citations. From this analysis, we distill a recipe for crafting impactful reference lists, at least in ecology.
  • Kalu, Subin; Simojoki, Asko; Karhu, Kristiina; Tammeorg, Priit (2021)
    Biochars (BC) have tremendous potential in mitigating climate change, and offer various agricultural and environmental benefits. However, there is limited information about the long-term effects of added biochars particularly from boreal regions. We studied the effects of a single application of softwood biochars on two contrasting boreal agricultural soils (nutrient-poor, coarse textured Umbrisol and fertile, fine-textured Stagnosol), both with high initial soil organic carbon contents, over eight years following the application. We focused on plant nutrient contents and nutrient uptake dynamics of different field crops over these years, as well as on soil physical properties and greenhouse gas emissions during seven to nine growing seasons. We found that, added biochars had minor long-term effects on the crop biomass yield, plant nutrient contents and plant nutrient uptake in both soil types. In terms of crop biomass yields, significant biochar × fertilization interactions were observed in barley (in 2013) and peas (in 2016), three and six years after the application of biochar in Stagnosol, respectively. In both cases, the biochar combined with the normal fertilization rate (100% of the recommended value) significantly increased crop biomass yield compared to corresponding fertilization treatment without biochar. However, the biochar had no effect at a lower fertilization rate (30% of the recommended value). Similar significant biochar × fertilization interactions were observed for several plant nutrient contents for peas in 2016, and for uptake for both barley in 2013 and peas in 2016. Thus, the ability of biochar to enhance the supply of nutrients to plants and hence to improve the crop biomass yield exists in boreal conditions, although these effects were minimal and not consistent over the years. Biochar notably increased plant K content, and also increased K:Mg ratio in plant biomass, suggesting a possible antagonistic effect of K on Mg in Umbrisol. Similar K antagonism on Na was observed in Stagnosol. The applied biochar also reduced the plant content and uptake of Al and Na in several years in Stagnosol. Furthermore, we found that, increased plant Mn content with biochar in the initial years subsequently declined over the following years in Umbrisol. On the other hand, the relative plant contents of Cd and Ni in Umbrisol, and P, K, Mg, S, Al, Cu, Fe and Ni in Stagnosol increased over the years. Despite these increased plant contents, no significant improvement was observed in crop biomass yield by added biochar over the years. The enhanced plant available water and reduced bulk density previously reported during the initial years were faded in long-term, likely due to dilution of biochar concentration in topsoil. However, the potential of biochar to affect N2O emission persisted, even seven years after the application.
  • Asmala, Eero; Carstensen, Jacob; Räike, Antti (2019)
    Increases of riverine organic carbon concentrations have been observed across the northern hemisphere over the past few decades. These increases are the result of multiple environmental drivers, but the relative importance of the drivers is still unclear. We analyzed a dataset of >10 000 observations of riverine total organic carbon (TOC) concentrations and associated water chemistry and hydrological observations from 1993 to 2017. The observations span a ~600 km north–south gradient from 30 individual river systems in Finland. Our data show significantly increasing TOC concentrations in 25 out of 30 systems, with an average increase from 12.0 to 15.1 mg l−1. The observed increase in riverine TOC concentrations led to an increase of 0.28 Mt in annual TOC load to the Baltic Sea from 1993 level to 2017 level. We analyzed the role of three putative environmental drivers of the observed TOC trends. Multiple regression analysis revealed that the most common driver was discharge, which alone explained TOC increases in 13 rivers, whereas pH and temperature were less important drivers (sole predictor in one and zero rivers, respectively). Different permutations of these three drivers were also found to be significant; the combination of discharge and pH being the most common (4 rivers). Land use was not in general linked with trends in TOC, except for the proportion of ditched land in the catchment, which was significantly correlated with increases in TOC concentration. Land use showed significant relationships with trends in discharge and pH. We also found that catchment characteristics are regulating the extent of these regional or global environmental changes causing the upward trends of riverine organic carbon.
  • Bernardi, Luciano; Gordin, Daniel; Bordino, Marco; Rosengard-Barlund, Milla; Sandelin, Anna; Forsblom, Carol; Groop, Per-Henrik (2017)
    Hyperoxia and slow breathing acutely improve autonomic function in type-1 diabetes. However, their effects on arterial function may reveal different mechanisms, perhaps potentially useful. To test the effects of oxygen and slow breathing we measured arterial function (augmentation index, pulse wave velocity), baroreflex sensitivity (BRS) and oxygen saturation (SAT), during spontaneous and slow breathing (6 breaths/min), in normoxia and hyperoxia (5 L/min oxygen) in 91 type-1 diabetic and 40 age-matched control participants. During normoxic spontaneous breathing diabetic subjects had lower BRS and SAT, and worse arterial function. Hyperoxia and slow breathing increased BRS and SAT. Hyperoxia increased blood pressure and worsened arterial function. Slow breathing improved arterial function and diastolic blood pressure. Combined administration prevented the hyperoxia-induced arterial pressure and function worsening. Control subjects showed a similar pattern, but with lesser or no statistical significance. Oxygen-driven autonomic improvement could depend on transient arterial stiffening and hypertension (well-known irritative effect of free-radicals on endothelium), inducing reflex increase in BRS. Slow breathing-induced improvement in BRS may result from improved SAT, reduced sympathetic activity and improved vascular function, and/or parasympathetic-driven antioxidant effect. Lower oxidative stress could explain blunted effects in controls. Slow breathing could be a simple beneficial intervention in diabetes.
  • Santos, Micaela; Cagnolo, Luciano; Roslin, Tomas; Ruperto, Emmanuel; Bernaschini, María Laura; Vázquez, Diego (2021)
    Studying how habitat loss affects the tolerance of ecological networks to species extinction (i.e. their robustness) is key for our understanding of the influence of human activities on natural ecosystems. With networks typically occurring as local interaction networks interconnected in space (a meta-network), we may ask how the loss of specific habitat fragments affects the overall robustness of the meta-network. To address this question, for an empirical meta-network of plants, herbivores and natural enemies we simulated the removal of habitat fragments in increasing and decreasing order of area, age and connectivity for plant extinction and the secondary extinction of herbivores, natural enemies and their interactions. Meta-network robustness was characterized as the area under the curve of remnant species or interactions at the end of a fragment removal sequence. To pinpoint the effects of fragment area, age and connectivity, respectively, we compared the observed robustness for each removal scenario against that of a random sequence. The meta-network was more robust to the loss of old (i.e. long-fragmented), large, connected fragments than of young (i.e. recently fragmented), small, isolated fragments. Thus, young, small, isolated fragments may be particularly important to the conservation of species and interactions, while contrary to our expectations larger, more connected fragments contribute little to meta-network robustness. Our findings highlight the importance of young, small, isolated fragments as sources of species and interactions unique to the regional level. These effects may largely result from an unpaid extinction debt, whereby younger fragments are likely to lose species over time. Yet, there may also be more long-lasting effects from cultivated lands (e.g. water, fertilizers and restricted cattle grazing) and network complexity in small, isolated fragments. Such fragments may sustain important biological diversity in fragmented landscapes, but maintaining their conservation value may depend on adequate restoration strategies.
  • Soinne, Helena; Keskinen, Riikka; Räty, Mari; Kanerva, Sanna; Turtola, Eila; Kaseva, Janne; Nuutinen, Visa; Simojoki, Asko; Salo, Tapio (2021)
    To achieve appropriate yield levels, inherent nitrogen (N) supply and biological N fixation are often complemented by fertilization. To avoid economic losses and negative environmental impacts due to over-application of N fertilizer, estimation of the inherent N supply is critical. We aimed to identify the roles of soil texture and organic matter in N mineralization and yield levels attained in cereal cultivation with or without N fertilization in boreal mineral soils. First, the net N mineralization and soil respiration were measured by laboratory incubation with soil samples varying in clay and organic carbon (C) contents. Secondly, to estimate the inherent soil N supply under field conditions, both unfertilized and fertilized cereal yields were measured in fields on clay soils (clay 30-78%) and coarse-textured soils (clay 0-28%). In clay soils (C 2.5-9.0%), both the net N mineralization and the cereal yields (without and with fertilization) decreased with increasing clay/C ratio. Moreover, in soils with high clay/C ratio, the agronomic N use efficiency (additional yield per kg of fertilizer N) varied considerably, indicating the presence of growth limitations other than N. In coarse-textured soils, the yield increase attained by fertilization increased with increasing organic C. Our results indicate that for clay soils in a cool and humid climate, the higher the clay content, the more organic C is needed to produce reasonable yields and to ensure efficient use of added nutrients without high N losses to the environment. For coarse soils having a rather high mean organic C of 2.3%, the organic C appeared to improve agronomic N use efficiency. For farmers, simple indicators such as the clay/C ratio or the use of non-N-fertilized control plots may be useful for site-specific adjustment of the rates of N fertilization. Highlights We aimed to identify simple indicators of inherent soil N supply applicable at the farm level. In clay soils, the net N mineralization was found to correlate negatively with the clay/C ratio. In coarse-textured soils, agronomic N use efficiency improved with increasing soil organic C. Clay soils with high clay/C ratio are at risk of low yield levels.
  • O'Toole, John M.; Pavlidis, Elena; Korotchikova, Irina; Boylan, Geraldine B.; Stevenson, Nathan J. (2019)
    For the premature newborn, little is known about changes in brain activity during transition to extra-uterine life. We aim to quantify these changes in relation to the longer-term maturation of the developing brain. We analysed EEG for up to 72 hours after birth from 28 infants born