Evaluation of the plant biostimulant effects of selected eukaryotic green microalgae

Microalgae are ubiquitous photosynthetic microorganisms found in nature. They have been reported to synthesize many bioactive chemicals that stimulate plant development. Our experiments aimed to examine the effects of three selected strains of eukaryotic green microalgae on plant growth. Two Chlorella species (Mosonmagyaróvár Algal Culture Collection (MACC)-360 and MACC-38) and a Chlamydomonas reinhardtii strain (cc124) were examined in Medicago truncatula, A17 ecotype, in the first portion of our investigation. First, using growth curves and microscopy, the growth patterns, cell size, and morphology of the microalgal strains were determined. In addition, their ability to synthesize auxins was evaluated. In the greenhouse, M. truncatula was grown in pots containing a mixture of vermiculite and soil (1:3) with a clay layer at the bottom. Living algae cells were applied to the plants using the soil drench method. The plants' physiological reactions to adding algal biomass were comprehensively studied. Microalgae substantially boosted the plant's stem length, leaf size, fresh weight, number of flowers, and pigment content. For most of the investigated factors, there was a strain-specific effect. Overall, the application of Chlorella sp. MACC-360 resulted in more robust plants with greater fresh biomass, larger leaves, and more flowers/pods than the control, which received the same total nutrients. In the second phase of the investigation, the biostimulant effects of Chlorella sp. MACC-360 and C. reinhardtii cc124 on Solanum lycopersicum (tomato) were studied. This study's first purpose was to determine whether the two strains had biostimulant effects on tomato plants. The significance of application mode and timing (plant age) was also studied. Thirdly, the strain-specific effects of the two algal strains were evaluated. Finally, transcriptome and metagenomic analyses were conducted to identify the molecular effect of algae and the microbial community of the rhizosphere. Tomatoes were grown in pots with a clay layer at the bottom and a mixture of soil and vermiculate (2:1). In two sets of trials, living algae and algal extract and living algae and spent media plus extracts were applied to the soil and plant leaves, respectively. In the first group, the culture suspension (treatment A) was centrifuged, the algae pellet was re-suspended in water to make (Treatment B), and this was applied weekly to the soil, while the algae extract (cell disrupted algae suspension – Treatment C) was sprayed on the leaves bi-weekly. Analyses were conducted on the blooming process, plant morphology, fruit characteristics, and pigment content. In the second set of tests, culture suspension (A) was administered weekly to the soil, and C was sprayed bi-weekly on the leaves. The kinetics of flowering, reproductive capability, and photosynthetic characteristics were investigated. Both algal strains enhanced the leaf pigments, fruit weight, and fruit diameter. The age of the plant at the onset of treatment was a significant determinant of the outcome; treatments initiated later (week 5) produced superior results than those initiated at a juvenile level (week 1). Chlorella sp. MACC-360 stimulated early blooming and fruit development, whereas C. reinhardtii cc124 greatly slowed these processes. Chlorella facilitated the transformation of light energy into chemical energy, whereas Chlamydomonas boosted the protection of photosynthetic parameters. Both strains increased leaf thickness and leaf temperature differential. Both algal strains enhanced crucial agronomically useful tomato processes. The upregulation of genes involved in systemic resistance demonstrated that microalgae readied plants to respond to abiotic stress and pathogen attacks, as evidenced by the transcription data. According to soil metagenomics research results, algae influenced the construction of the tomato rhizosphere microbiome. In soils saturated with microalgae, the number of Ascomycota fungus, Streptomyces, Brevundimonas, and other helpful bacteria that provided plant nutrition and defense against dangerous microbes increased

A tool for estimating Best Management Practice effectiveness in Arkansas

Increased nutrient and sediment losses from expanding agricultural practices and urban development in Arkansas are important environmental concerns. Best Management Practices (BMPs) are being implemented to lessen the effects of these developments on existing water bodies. There is, however, insufficient scientific base as to the effectiveness of these practices. A number of studies have been conducted in recent years to determine BMP effectiveness. Data from these studies can only be reliably used for the individual site from which they were obtained. When considered collectively, these data comprise quantitative effectiveness over a wide range of conditions and can thus be used to provide reliable estimates of BMP effectiveness. This study develops a tool for estimating BMP effectiveness, based on accumulation and analyses of data reported in previous studies, with a focus on site conditions and management interventions in Arkansas. This study incorporates data from a variety of regions in the southeastern U.S., which have site conditions and management similar to those in Arkansas. Developed within Microsoft® Access© from a pre-existing BMP characterization tool, this tool will be made accessible to local and state agencies and will aid rural and urban planners in developing management solutions for nutrients and sediment control. The tool describes individual BMPs in detail and gives site-specific estimates of their long-term effectiveness in sediment and nutrient control

Salinity Stress Responses and Adaptation Mechanisms in Eukaryotic Green Microalgae

High salinity is a challenging environmental stress for organisms to overcome. Unicellular photosynthetic microalgae are especially vulnerable as they have to grapple not only with ionic imbalance and osmotic stress but also with the generated reactive oxygen species (ROS) interfering with photosynthesis. This review attempts to compare and contrast mechanisms that algae, particularly the eukaryotic Chlamydomonas microalgae, exhibit in order to immediately respond to harsh conditions caused by high salinity. The review also collates adaptation mechanisms of freshwater algae strains under persistent high salt conditions. Understanding both short-term and long-term algal responses to high salinity is integral to further fundamental research in algal biology and biotechnology

Development of A Water Quality Status and Trend Detection Tool*

Water Quality Index (WQI) models have been developed since the early 1970s. They present a means by which water quality status and trends can be compared across time and space on the basis of a composite value computed using existing water quality data. There is a need for a tool that can bring the different water quality parameters together and calculate the WQIs so as to facilitate data use in predictive modeling and water quality management. We are developing a software tool that can be used by water quality managers and others with different technical backgrounds to calculate WQI of the water source in order to determine water quality status and predict potentially harmful conditions. In this paper, we describe the tool that we have developed and its effectiveness in calculating WQIs and presenting visual analysis of the data. The tool is developed using Python as the base language. Tributary data from 4 watersheds in the Western Lake Erie Basin from National Center for Water Quality Research (NCWQR) at Heidelberg University was fed into the software tool and results were obtained. In its preliminary state, the tool is able to read, process and analyze any amount of data from an Excel file when presented in the right format. Current outputs show interpretive water quality in the Western Lake Erie Basin, which has been bad (WQI \u3c 39) to medium (39 \u3c WQI \u3c 70) over the years, presented as time series charts with trend lines as well as tables. Future developments will include more in-depth predictive analysis as well as provisions for multiple file types and formats. In the future, we expect that the tool will be flexible enough that it can be adapted to other areas beyond the study region

Exploring The Nexus Between Crop Diversification and Household Welfare, in Borabu Sub-County, Kenya

Following the effects of climate change, there has been a resurgence of interest in promoting crop diversification as a climate-smart agricultural practice in Sub-Saharan Africa to improve food security, increase income, and reduce vulnerability to external shocks. This practice is considered an effective risk management strategy and consumption smoothing strategy in a context characterized by repeated exposure to shocks. Agricultural production in Kenya is mainly dependent on rain-fed cultivation, with maize as the principal staple food crop. However, staple crops face major challenges and therefore, a diversification from over-reliance on staples will be important as part of progress toward achieving food security. The Kenyan government has, for a long time, been promoting crop diversification to improve household welfare and minimize risks associated with heavy dependence on maize. A decline in maize yields associated with the emergence of new pests and diseases, such as maize lethal necrosis disease (MLND) in Borabu sub-county, emphasized the need for maize farmers to diversify away from maize production. Although this strategy is in use, there is no clear evidence of the impact it has on the livelihoods of vulnerable households. Thus, the study sought to find out the nexus between crop diversification and household welfare among small-scale farming households in Borabu sub-county. Multi-stage sampling procedure was used to select a representative sample size of 385 small-scale farmers. Primary data was collected using observations and interviews with the help of a semi-structured questionnaire. The data were analyzed using the STATA computer program. This paper adopted the Endogenous Switching Regression Model to determine the nexus between crop diversification and household welfare, with household welfare being proxied by household financial savings. The findings indicate that smallholder maize farmers who practiced crop diversification experienced an enhanced ability to save than a random individual would have experienced. Keywords: Crop diversification, household welfare, Maize Lethal Necrosis Disease, Endogenous Switching Regression Model. DOI: 10.7176/JBAH/13-8-07 Publication date:May 31st 202

Sexual and reproductive health needs of adolescents living with HIV in Kenya

The objective of this study was to assess the sexual and reproductive health needs of adolescents living with HIV in Kenya with a view to identifying and developing interventions that integrate these needs within the existing HIV/AIDS treatment, care, and support programs in the country. The study was a result of collaboration between Population Council, APHIA II Rift Valley and Coast (Family Health International), the National AIDS and STI Control Programme, and APHIA II Nairobi and Central (Pathfinder International). Major findings indicate that many of the adolescents living with HIV are vulnerable, and that programmatic gaps exist in addressing the sexual and reproductive health needs of HIV-positive adolescents. The project’s recommendations include: strengthening the provision of information and services on family planning and HIV prevention; ensuring effective provision of PMTCT services for HIV-positive adolescents during pregnancy; updating the existing counseling and support packages to include sexual and reproductive health information and services; mechanisms for involving parents/guardians in discussion of sexual and reproductive health issues with HIV-positive adolescents; and strengthening life-skills training for HIV-positive adolescents

Comparative Study of Different Stochastic Weather Generators for Long-Term Climate Data Simulation

Climate is one of the single most important factors affecting watershed ecosystems and water resources. The effect of climate variability and change has been studied extensively in some places; in many places, however, assessments are hampered by limited availability of long-term continuous climate data. Weather generators provide a means of synthesizing long-term climate data that can then be used in natural resource assessments. Given their potential, there is the need to evaluate the performance of the generators; in this study, three commonly used weather generators—CLImate GENerator (CLIGEN), Long Ashton Research Station Weather Generator (LARS-WG), and Weather Generators (WeaGETS) were compared with regard to their ability to capture the essential statistical characteristics of observed data (distribution, occurrence of wet and dry spells, number of snow days, growing season temperatures, and growing degree days). The study was based on observed 1966–2015 weather station data from the Western Lake Erie Basin (WLEB), from which 50 different realizations were generated, each spanning 50 years. Both CLIGEN and LARS-WG performed fairly well with respect to representing the statistical characteristics of observed precipitation and minimum and maximum temperatures, although CLIGEN tended to overestimate values at the extremes. This generator also overestimated dry sequences by 18%–30% and snow-day counts by 12%–19% when considered over the entire WLEB. It (CLIGEN) was, however, well able to simulate parameters specific to crop growth such as growing degree days and had an added advantage over the other generators in that it simulates a larger number of weather variables. LARS-WG overestimated wet sequence counts across the basin by 15%–38%. In addition, the optimal growth period simulated by LARS-WG also exceeded that obtained from observed data by 16%–29% basin-wide. Preliminary results with WeaGETS indicated that additional evaluation is needed to better define its parameters. Results provided insights into the suitability of both CLIGEN and LARS-WG for use with water resource applications

Evaluation of the biostimulant effects of two Chlorophyta microalgae on tomato (Solanum lycopersicum)

Eukaryotic microalgae from the Chlorophyta division are used in various bio-industries due to their ability to produce high value compounds. Some of these compounds show plant biostimulant properties when applied to plants, soil or growth medium in hydroponic chambers. The first objective of this study was to evaluate if Chlamydomonas reinhardtii cc 124 and Chlorella sp. MACC-360 had biostimulant effect on Solanum lycopersicum L. The second objective was to investigate the importance of the application mode and time. The third goal was to reveal strain-specific actions of the two algae strains. Tomato plants were grown in pots layered with clay at the bottom and filled with the mixture of soil and vermiculate. In two sets of experiments the soil and plant leaves were treated with living algae and algal extract, respectively. In the first set, the culture suspension (CS) was centrifuged, the algae pellet was re-suspended in water (CCS), and this was applied weekly to soil, while algae extract (cell disrupted algae suspension - CDS) was sprayed on leaves bi-weekly. The flowering process, plant morphology, fruit features and pigment contents were analyzed. In the second set of experiments, the culture suspension per se (CS) was applied to the soil weekly and CDS was sprayed on leaves bi-weekly. Flowering kinetics, reproductive capacity and photosynthetic parameters were examined. Both algae strains increased pigment content, fruit weight and fruit diameter of tomato. Plants that received initial algae treatment at an advanced age performed better than those initially treated at a young age. Chlorella induced early flowering and fruit development while Chlamydomonas significantly delayed these milestone functions. Chlorella promoted conversion of light energy to chemical energy, while Chlamydomonas enhanced protection of photosynthetic parameters. Both strains increased leaf temperature differential as well as leaf thickness. Overall, both algae strains stimulated important agronomic-valuable functions in tomato

APOE4 genotype exerts greater benefit in lowering plasma cholesterol and apolipoprotein B than wild type (E3/E3), after replacement of dietary saturated fats with low glycaemic index carbohydrates

We examined the impact of APOE genotype on plasma lipids and glucose in a secondary analysis of data from a five-arm, randomised controlled, parallel dietary intervention trial ('RISCK' study), to investigate the impact of replacing saturated fatty acids (SFA) with either monounsaturated fat (MUFA) or carbohydrate of high or low glycaemic index (GI) on CVD risk factors and insulin sensitivity. We tested the impact of APOE genotype (carriage of E2 and E4 alleles versus E3/E3), determined retrospectively, on plasma lipids, lipoproteins and glucose homeostasis at baseline (n = 469), and on the change in these variables after 24 weeks of dietary intervention (n = 389). At baseline, carriers of E2 (n = 70), E4 (n = 125) and E3/E3 (n = 274) expressed marked differences in total plasma cholesterol (TC, p = 0.001), low density lipoprotein cholesterol (LDL-C, p E3/E3 > E2. Following intervention, there was evidence of a significant diet x genotype interaction with significantly greater decreases in TC (p = 0.02) and apo B (p = 0.006) among carriers of E4 when SFA was replaced with low GI carbohydrate on a lower fat diet (TC -0.28 mmol/L p = 0.03; apo B -0.1 g/L p = 0.02), and a relative increase in TC (in comparison to E3/E3) when SFA was replaced with MUFA and high GI carbohydrates (TC 0.3 mmol/L, p = 0.03). Among carriers of E2 (compared with E3/E3) there was an increase in triacylglycerol (TAG) when SFA was replaced with MUFA and low GI carbohydrates 0.46 mmol/L p = 0.001). There were no significant interactions between APOE genotype and diet for changes in indices of glucose homeostasis. In conclusion, variations in APOE genotype led to differential effects on the lipid response to the replacement of SFA with MUFA and low GI carbohydrates

Impact of opioid substitution therapy on antiretroviral therapy outcomes:a systematic review and meta-analysis

BACKGROUND: Human immunodeficiency virus (HIV)-infected people who inject drugs (PWID) frequently encounter barriers accessing and remaining on antiretroviral therapy (ART). Some studies have suggested that opioid substitution therapy (OST) could facilitate PWID's engagement with HIV services. We conducted a systematic review and meta-analysis to evaluate the impact of concurrent OST use on ART-related outcomes among HIV-infected PWID. METHODS: We searched Medline, PsycInfo, Embase, Global Health, Cochrane, Web of Science, and Social Policy and Practice databases for studies between 1996 to November 2014 documenting the impact of OST, compared to no OST, on ART outcomes. Outcomes considered were coverage and recruitment onto ART, adherence, viral suppression, attrition from ART, and mortality. Meta-analyses were conducted using random-effects modeling, and heterogeneity assessed using Cochran Q test and I2 statistic. RESULTS: We identified 4685 articles, and 32 studies conducted in North America, Europe, Indonesia, and China were included. OST was associated with a 69% increase in recruitment onto ART (hazard ratio [HR], 1.69; 95% confidence interval [CI], 1.32-2.15), a 54% increase in ART coverage (odds ratio [OR], 1.54; 95% CI, 1.17-2.03), a 2-fold increase in adherence (OR, 2.14; 95% CI, 1.41-3.26), and a 23% decrease in the odds of attrition (OR, 0.77; 95% CI, .63-.95). OST was associated with a 45% increase in odds of viral suppression (OR, 1.45; 95% CI, 1.21-1.73), but there was limited evidence from 6 studies for OST decreasing mortality for PWID on ART (HR, 0.91; 95% CI, .65-1.25). CONCLUSIONS: These findings support the use of OST, and its integration with HIV services, to improve the HIV treatment and care continuum among HIV-infected PWID