Direct detection of atmospheric particle formation using the Neutral cluster and Air Ion Spectrometer

Aerosol particles play an important role in the Earth s atmosphere and in the climate system: they scatter and absorb solar radiation, facilitate chemical processes, and serve as seeds for cloud formation. Secondary new particle formation (NPF) is a globally important source of these particles. Currently, the mechanisms of particle formation and the vapors participating in this process are, however, not truly understood. In order to fully explain atmospheric NPF and subsequent growth, we need to measure directly the very initial steps of the formation processes. This thesis investigates the possibility to study atmospheric particle formation using a recently developed Neutral cluster and Air Ion Spectrometer (NAIS). First, the NAIS was calibrated and intercompared, and found to be in good agreement with the reference instruments both in the laboratory and in the field. It was concluded that NAIS can be reliably used to measure small atmospheric ions and particles directly at the sizes where NPF begins. Second, several NAIS systems were deployed simultaneously at 12 European measurement sites to quantify the spatial and temporal distribution of particle formation events. The sites represented a variety of geographical and atmospheric conditions. The NPF events were detected using NAIS systems at all of the sites during the year-long measurement period. Various particle formation characteristics, such as formation and growth rates, were used as indicators of the relevant processes and participating compounds in the initial formation. In a case of parallel ion and neutral cluster measurements, we also estimated the relative contribution of ion-induced and neutral nucleation to the total particle formation. At most sites, the particle growth rate increased with the increasing particle size indicating that different condensing vapors are participating in the growth of different-sized particles. The results suggest that, in addition to sulfuric acid, organic vapors contribute to the initial steps of NPF and to the subsequent growth, not just later steps of the particle growth. As a significant new result, we found out that the total particle formation rate varied much more between the different sites than the formation rate of charged particles. The results infer that the ion-induced nucleation has a minor contribution to particle formation in the boundary layer in most of the environments. These results give tools to better quantify the aerosol source provided by secondary NPF in various environments. The particle formation characteristics determined in this thesis can be used in global models to assess NPF s climatic effects.

On the charging state of atmospheric aerosols and ion-induced nucleation

Floating in the air that surrounds us is a number of small particles, invisible to the human eye. The mixture of air and particles, liquid or solid, is called an aerosol. Aerosols have significant effects on air quality, visibility and health, and on the Earth's climate. Their effect on the Earth's climate is the least understood of climatically relevant effects. They can scatter the incoming radiation from the Sun, or they can act as seeds onto which cloud droplets are formed. Aerosol particles are created directly, by human activity or natural reasons such as breaking ocean waves or sandstorms. They can also be created indirectly as vapors or very small particles are emitted into the atmosphere and they combine to form small particles that later grow to reach climatically or health relevant sizes. The mechanisms through which those particles are formed is still under scientific discussion, even though this knowledge is crucial to make air quality or climate predictions, or to understand how aerosols will influence and will be influenced by the climate's feedback loops. One of the proposed mechanisms responsible for new particle formation is ion-induced nucleation. This mechanism is based on the idea that newly formed particles were ultimately formed around an electric charge. The amount of available charges in the atmosphere varies depending on radon concentrations in the soil and in the air, as well as incoming ionizing radiation from outer space. In this thesis, ion-induced nucleation is investigated through long-term measurements in two different environments: in the background site of Hyytiälä and in the urban site that is Helsinki. The main conclusion of this thesis is that ion-induced nucleation generally plays a minor role in new particle formation. The fraction of particles formed varies from day to day and from place to place. The relative importance of ion-induced nucleation, i.e. the fraction of particles formed through ion-induced nucleation, is bigger in cleaner areas where the absolute number of particles formed is smaller. Moreover, ion-induced nucleation contributes to a bigger fraction of particles on warmer days, when the sulfuric acid and water vapor saturation ratios are lower. This analysis will help to understand the feedbacks associated with climate change.

Management of bushland vegetation using rainwater harvesting in eastern Kenya.

Microcatchment water harvesting (MCWH) improved the survival and growth of planted trees on heavy soils in eastern Kenya five to six years after planting. In the best method, the cross-tied furrow microcatchments, the mean annual increments (MAI; based on the average biomass of living trees multiplied by tree density and survival) of the total and usable biomass in Prosopis juliflora were 2787 and 1610 kg ha-1 a-1 respectively, when the initial tree density was 500 to 1667 trees per hectare. Based on survival, the indigenous Acacia horrida, A. mellifera and A. zanzibarica were the most suitable species for planting using MCWH. When both survival and yield were considered, a local seed source of the introduced P. juliflora was superior to all other species. The MAI in MCWH was at best distinctly higher than that in the natural vegetation (163­307 and 66­111 kg ha-1 a-1 for total and usable biomass respectively); this cannot satisfy the fuelwood demand of concentrated populations, such as towns or irrigation schemes. The density of seeds of woody species in the topsoil was 40.1 seeds m-2 in the Acacia-Commiphora bushland and 12.6 seeds m-2 in the zone between the bushland and the Tana riverine forest. Rehabilitation of woody vegetation using the soil seed bank alone proved difficult due to the lack of seeds of desirable species. The regeneration and dynamics of woody vegetation were also studied both in cleared and undisturbed bushland. A sub-type of Acacia-Commiphora bushland was identified as Acacia reficiens bushland, in which the dominant Commiphora species is C. campestris. Most of the woody species did not have even-aged populations but cohort structures that were skewed towards young individuals. The woody vegetation and the status of soil nutrients were estimated to recover in 15­20 years on Vertic Natrargid soils after total removal of above-ground vegetation.

Purification and characterization of three toxins and two agglutinins from Abrus precatorius seed by using lactamyl-Sepharose affinity chromatography

Three toxins, abrin-I, -II, and -III, and two agglutinins, APA-I and -II, were purified from the seeds of Abrus precatorius by lactamyl-Sepharose affinity chromatography followed by gel filtration and DEAE-Sephacel column chromatography. abrin-I did not bind on DEAE-Sephacel column chromatography and the bound abrin-II, abrin-III, APA-I, and APA-II were eluted with a sodium acetate gradient. The identity of each protein was established by sodium dodecylsulfate-polyacrylamide gel electrophoresis and isoelectric focusing. The relative molecular weights are abrin-I, 64,000; abrin-II and abrin-III, 63,000 each: APA-I, 130,000; and APA-II, 128,000. Isoelectric focusing revealed microheterogeneity due to the presence of isoforms in each protein. Toxicity and binding studies further confirmed the differences among the lectins. The time course of inhibition of protein synthesis in thymocytes by the toxins showed lag times of 78, 61, and 72 min with Ki's of 0.55, 0.99, and 0.74 ms−1 at a 0.63 nImage concentration of each of abrin-I, -II, and -III, respectively. A Scatchard plot obtained from the equilibrium measurement for the lectins binding to lactamyl-Sepharose beads showed nonlinearity, indicating a cooperative mode of binding which was not observed for APA-I binding to Sepharose 4B beads. Further, by the criterion of the isoelectric focusing profile, it was shown that the least toxic abrin-I and the highly toxic abrin-II isolated by lactamyl-Sepharose chromatography were not retained on a low-affinity Sepharose 4B matrix, which signifies the necessity of using a high-affinity matrix for the purification of the lectins.

Viherrevonhäntä ja kananhirssi vieraslajeina Suomessa

Kasvit ovat kautta aikojen levinneet uusille elinpaikoille. Kasvin asettumista uuteen paikkaan voidaan tarkastella prosessina, jossa on erilaisia vaiheita ja eri vaiheissa eri tekijät ovat tärkeitä. Ilmasto ja erityisesti lämpötila vaikuttavat kasvien levinneisyyteen ja leviämiseen uusille paikoille ja siksi ilmaston lämpenemisen ennustetaan siirtävän kasvien levinneisyysalueita kohti pohjoista. On mahdollista, että Suomeenkin leviäisi etelämmästä muiden kasvien ohella haitallisia rikkakasvilajeja, kuten esimerkiksi viherrevonhäntä (Amaranthus retroflexus L.) ja kananhirssi (Echinochloa crus-galli L. Beauv.). Tämän tutkimuksen tarkoituksena oli selvittää, selviävätkö viherrevonhäntä ja kananhirssi Suomessa pelto-olosuhteissa ja pohtia niiden vakiintumisen ja leviämisen mahdollisuuksia. Toinen tarkoitus oli selvittää ilmaston lämpenemisen vaikutusta näiden rikkakasvien kasvuun. Tutkimus suoritettiin kenttä- sekä kasvihuonekokeena. Viherrevonhäntä kasvoi pellolla hyvin huolimatta myöhäisestä itämisestä, mutta kananhirssi iti ja kasvoi pellolla huonosti. Kasvihuoneessa molemmat kasvoivat hyvin. Kilpailu vähensi viherrevonhännän ja kananhirssin vegetatiivista kasvua vain kasvihuoneessa, mutta siementuottoon kilpailu vaikutti sekä kasvihuoneessa että pellolla. Kasvihuoneessa korkeampi lämpötila ei vaikuttanut viherrevonhännän tai kananhirssin vegetatiiviseen kasvuun, mutta viherrevonhännän siementuotto parani lämpimämmässä. Lämpötilalla ei ollut vaikutusta kananhirssin siementuotantoon. Tutkimuksen tuloksista voidaan päätellä, että viherrevonhäntä voi hyvinkin kasvaa Suomessa jo nykyisissä lämpötiloissa, mutta siementuotto ei välttämättä olisi varmaa. Viherrevonhäntä voisi näin ollen hyötyä tulevaisuuden pidemmästä kasvukaudesta. Kananhirssin osalta tulokset olivat ristiriitaiset ja ilmaston lämpenemisen vaikutuksia kananhirssiin on tämän tutkimuksen perusteella hankala arvioida.

Jatrophanviljely ja maankäyttö Vietnamissa

Biofuels are under discussion all over the world today. There are fears that the farming of biofuel plants hurts food production and weakens the food security of the poor. On the other hand, biofuel production could lessen the green house gas emissions caused by transportation, and it could also spread the profits from fuel markets more evenly between countries. The aim of this thesis is to find out how an oil plant called jatropha curcas L., which is used for biodiesel production, can affect the sustainability of livelihoods in Vietnam from the point of view of land use. Special attention is given to the effects of jatropha farming on food production, land productivity, natural resources of livelihoods and global livelihood. Jatropha belongs to the family Euphorbiaceae, and it grows naturally in tropical and subtropical areas. It can be grown on poor soils, its seeds have high oil content, and it cannot be eaten due to its toxicity. The plant grows naturally in Vietnam, and during the past few years it has also begun to be farmed for making biodiesel. Population growth in Vietnam has slowed down, but the population's standard of living and energy consumption are still rising quickly. An interest in the international biodiesel markets has awoken following Vietnam's opening up to international trade. Jatropha diesel plays a significant part in Vietnam’s clean fuel strategy, and many companies have set up jatropha plantations to produce raw material for biodiesel. Diesel made from jatropha is planned to be used both locally and for export. This thesis uses a theoretical concept of sustainable livelihoods. According to the theory, the resources that people have shape their livelihood possibilities. Farming of jatropha affects the livelihoods of people especially through land use, as land use changes have effects on many of the livelihood resources. In addition to the written sources, the material of the thesis is based on 14 interviews in Vietnam and Finland, and on observation during a field trip to Northern Vietnam in the spring of 2008. The results of the thesis show that jatropha diesel can support the sustainability of livelihoods at different scales if it is produced with deliberation. However, positive results are only possible if decisions are made carefully and more experience is collected. The possibilities of sustainable jatropha farming depend mainly on the previous land use methods and ways of production. Farming of jatropha does not threaten food production in Vietnam if the farming plans are implemented as planned. Jatropha may take some land from cassava, but at the same time, food production can be increased if mixed farming is used on some farms. Plenty of new research information and practical experiences on jatropha farming has to be collected before results of the real sustainability of the farming are ready. Carefully considered continuation and documentation of present and future projects would help to understand the possibilities of jatropha diesel in Vietnam and elsewhere.

Nutritional evaluation of silage made from the toxic weed parthenium hysterophorus in animals

After ensilation, the toxic Compositae weed Parthenium hysterophorus was devoid of the toxic principle parthenin. Laboratory-scale ensilation indicated that no parthenin was detectable after 5 wk of anaerobic fermentation. For animal feeding studies, silage was made on a large scale from Parthenium mixed with maize or from Parthenium alone. Crossbred bull and buffalo bull calves were fed diets containing the silages, or control diet without silage, for 12 wk. The animals consumed both silages with relish, and body weight gains of silage-fed calves did not differ from those of the controls. The digestibilities of dry matter, fibre and nitrogen-free extract were greater with the control diet, but the biological value of proteins tended to be greater with the silage-containing diets. Haematological studies indicated no significant differences between experimental and control groups in selected parameters, except for a reduction in blood urea nitrogen in the animals fed silage. The possible causes for these biochemical alterations are discussed. Since the nutritive value of Parthenium silage compares favourably with the standard diet, and Parthenium seeds collected from the silage did not germinate, we suggest that ensilation can be used as an additional method in the containment and eradication of these plants, which grow wild in India.

The 'neighbour effect' and its role in shaping the positional pattern of seed development in fruits: An illustration from the pods of Erythrina suberosa

Plants exhibit certain intra-fruit positional patterns in the development of seeds. These patterns have been generally interpreted to be a consequence of resource and fertilization gradients. However, such positional patterns might also be shaped by the 'neighbour effect', wherein formation and development of a seed at any position might positively or negatively influence those of other seeds in the neighbourhood. In this article, we examine the role of such neighbour effect in shaping the positional pattern of seeds in the pods of Erythrina suberosa. The results suggest the existence of a positive neighbour effect leading to a higher frequency of seeds in contiguous positions.

Studies on molecular evolution and structural features of double-headed inhibitors of ?-amylase and trypsin in plants

Plant seeds usually have high concentrations of proteinase and amylase inhibitors. These inhibitors exhibit a wide range of specificity, stability and oligomeric structure. In this communication, we report analysis of sequences that show statistically significant similarity to the double-headed alpha-amylase/trypsin inhibitor of ragi (Eleusine coracana). Our aim is to understand their evolutionary and structural features. The 14 sequences of this family that are available in the SWISSPROT database form three evolutionarily distinct branches. The branches relate to enzyme specificities and also probably to the oligomeric state of the proteins and not to the botanical class of the plant from which the enzymes are derived. This suggests that the enzyme specificities of the inhibitors evolved before the divergence of commercially cultivated cereals. The inhibitor sequences have three regions that display periodicity in hydrophobicity. It is likely that this feature reflects extended secondary structure in these segments. One of the most variable regions of the polypeptide corresponds to a loop, which is most probably exposed in the native structure of the inhibitors and is responsible for the inhibitory property.

Heterologous expression of P5CS gene in chickpea enhances salt tolerance without affecting yield

Vigna Delta(1)-pyrroline-5-carboxylate synthetase (P5CS) cDNA was transferred to chickpea (Cicer arietinum L.) cultivar Annigeri via Agrobacterium tumefaciens mediated transformation. Following selection on hygromycin and regeneration, 60 hygromycin-resistant plants were recovered. Southern blot analysis of five fertile independent lines of T0 and T1 generation revealed single and multiple insertions of the transgene. RT-PCR and Western blot analysis of T0 and T1 progeny demonstrated that the P5CS gene is expressed and produced functional protein in chickpea. T1 transgenic lines accumulated higher amount of proline under 250 mM NaCl compared to untransformed controls. Higher accumulation of Na(+) was noticed in the older leaves but negligible accumulation in seeds of T1 transgenic lines as compared to the controls. Chlorophyll stability and electrolyte leakage indicated that proline overproduction helps in alleviating salt stress in transgenic chickpea plants. The T1 transgenics lines were grown to maturity and set normal viable seeds under continuous salinity stress (250 mM) without any reduction in plant yield in terms of seed mass.

Retention Time Variability as a Mechanism for Animal Mediated Long-Distance Dispersal

Long-distance dispersal (LDD) events, although rare for most plant species, can strongly influence population and community dynamics. Animals function as a key biotic vector of seeds and thus, a mechanistic and quantitative understanding of how individual animal behaviors scale to dispersal patterns at different spatial scales is a question of critical importance from both basic and applied perspectives. Using a diffusion-theory based analytical approach for a wide range of animal movement and seed transportation patterns, we show that the scale (a measure of local dispersal) of the seed dispersal kernel increases with the organisms' rate of movement and mean seed retention time. We reveal that variations in seed retention time is a key determinant of various measures of LDD such as kurtosis (or shape) of the kernel, thinkness of tails and the absolute number of seeds falling beyond a threshold distance. Using empirical data sets of frugivores, we illustrate the importance of variability in retention times for predicting the key disperser species that influence LDD. Our study makes testable predictions linking animal movement behaviors and gut retention times to dispersal patterns and, more generally, highlights the potential importance of animal behavioral variability for the LDD of seeds.

Seed dispersal in changing landscapes

A growing understanding of the ecology of seed dispersal has so far had little influence on conservation practice, while the needs of conservation practice have had little influence on seed dispersal research. Yet seed dispersal interacts decisively with the major drivers of biodiversity change in the 21st century: habitat fragmentation, overharvesting, biological invasions, and climate change. We synthesize current knowledge of the effects these drivers have on seed dispersal to identify research gaps and to show how this information can be used to improve conservation management. The drivers, either individually, or in combination, have changed the quantity, species composition, and spatial pattern of dispersed seeds in the majority of ecosystems worldwide, with inevitable consequences for species survival in a rapidly changing world. The natural history of seed dispersal is now well-understood in a range of landscapes worldwide. Only a few generalizations that have emerged are directly applicable to conservation management, however, because they are frequently confounded by site-specific and species-specific variation. Potentially synergistic interactions between disturbances are likely to exacerbate the negative impacts, but these are rarely investigated. We recommend that the conservation status of functionally unique dispersers be revised and that the conservation target for key seed dispersers should be a population size that maintains their ecological function, rather than merely the minimum viable population. Based on our analysis of conservation needs, seed dispersal research should be carried out at larger spatial scales in heterogenous landscapes, examining the simultaneous impacts of multiple drivers on community-wide seed dispersal networks. (C) 2011 Elsevier Ltd. All rights reserved.

Jatropha cultivation in southern India: assessing farmers' experiences

Together with 106 farmers who started growing Jatropha (Jatropha curcas L.) in 20042006, this research sought to increase the knowledge around the real-life experience of Jatropha farming in the southern India states of Tamil Nadu and Andhra Pradesh. Launched as an alternative for diesel in India, Jatropha has been promoted as a non-edible plant that could grow on poor soils, yield oil-rich seeds for production of bio-diesel, and not compete directly with food production. Through interviews with the farmers, information was gathered regarding their socio-economic situation, the implementation and performance of their Jatropha plantations, and their reasons for continuing or discontinuing Jatropha cultivation. Results reveal that 82% of the farmers had substituted former cropland for their Jatropha cultivation. By 2010, 85% (n = 90) of the farmers who cultivated Jatropha in 2004 had stopped. Cultivating the crop did not give the economic returns the farmers anticipated, mainly due to a lack of information about the crop and its maintenance during cultivation and due to water scarcity. A majority of the farmers irrigated and applied fertilizer, and even pesticides. Many problems experienced by the farmers were due to limited knowledge about cultivating Jatropha caused by poor planning and implementation of the national Jatropha program. Extension services, subsidies, and other support were not provided as promised. The farmers who continued cultivation had means of income other than Jatropha and held hopes of a future Jatropha market. The lack of market structures, such as purchase agreements and buyers, as well as a low retail price for the seeds, were frequently stated as barriers to Jatropha cultivation. For Jatropha biodiesel to perform well, efforts are needed to improve yield levels and stability through genetic improvements and drought tolerance, as well as agriculture extension services to support adoption of the crop. Government programs will -probably be more effective if implementing biodiesel production is conjoined with stimulating the demand for Jatropha biodiesel. To avoid food-biofuel competition, additional measures may be needed such as land-use restrictions for Jatropha producers and taxes on biofuels or biofuel feedstocks to improve the competitiveness of the food sector compared to the bioenergy sector. (c) 2012 Society of Chemical Industry and John Wiley & Sons, Ltd

Detection of sugar-lectin interactions by multivalent dendritic sugar functionalized single-walled carbon nanotubes

We show that single walled carbon nanotubes (SWNTs) decorated with sugar functionalized poly (propyl ether imine) (PETIM) dendrimer is a very sensitive platform to quantitatively detect carbohydrate recognizing proteins, namely, lectins. The changes in electrical conductivity of SWNT in field effect transistor device due to carbohydrate-protein interactions form the basis of present study. The mannose sugar attached PETIM dendrimers undergo charge-transfer interactions with the SWNTs. The changes in the conductance of the dendritic sugar functionalized SWNT after addition of lectins in varying concentrations were found to follow the Langmuir type isotherm, giving the concanavalin A (Con A)-mannose affinity constant to be 8.5 x 10(6) M-1. The increase in the device conductance observed after adding 10 nM of Con A is same as after adding 20 mu M of a non-specific lectin peanut agglutinin, showing the high specificity of the Con A-mannose interactions. The specificity of sugar-lectin interactions was characterized further by observing significant shifts in Raman modes of the SWNTs. (C) 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.4739793]

A Bifunctional Enzyme That Has Both Monoacylglycerol Acyltransferase and Acyl Hydrolase Activities

Monoacylglycerol acyltransferase (MGAT) catalyzes the synthesis of diacylglycerol, the precursor of triacylglycerol biosynthesis and an important signaling molecule. Here, we describe the isolation and characterization of the peanut (Arachis hypogaea) MGAT gene. The soluble enzyme utilizes invariant histidine-62 and aspartate-67 residues of the acyltransferase motif for its MGAT activity. A sequence analysis revealed the presence of a hydrolase (GXSXG) motif, and enzyme assays revealed the presence of monoacylglycerol (MAG) and lysophosphatidylcholine (LPC) hydrolytic activities, indicating the bifunctional nature of the enzyme. The overexpression of the MGAT gene in yeast (Saccharomyces cerevisiae) caused an increase in triacylglycerol accumulation. Similar to the peanut MGAT, the Arabidopsis (Arabidopsis thaliana) homolog (At1g52760) also exhibited both acyltransferase and hydrolase activities. Interestingly, the yeast homolog lacks the conserved HX4D motif, and it is deficient in the acyltransferase function but exhibits MAG and LPC hydrolase activities. This study demonstrates the presence of a soluble MGAT/hydrolase in plants. The predicted three-dimensional homology modeling and substrate docking suggested the presence of two separate substrate (MAG and LPC)-binding sites in a single polypeptide. Our study describes a soluble bifunctional enzyme that has both MGAT and hydrolase functions.