scholarly journals Unravelling microalgal-bacterial interactions in aquatic ecosystems through 16S co-occurrence networks

2022 ◽  
Author(s):  
B.L.D Uthpala Pushpakumara ◽  
Kshitij Tandon ◽  
Anusuya Willis ◽  
Heroen Verbruggen

Microalgae and bacteria have a wide spectrum of associations in aquatic environments. Since their interactions can directly influence global carbon and nutrient cycling, understanding these associations help us evaluate their influence on ecosystem productivity. Algal biodiversity is large, and bacterial associations have been characterised for a small fraction of them. While experiments based on algal-bacterial co-culturing are commonly used to infer interactions, deciphering all associations present in nature through such methods is impractical and approaches based on co-occurrence network analysis can help infer associations. In this study, we used microbial co-occurrence networks built from Earth microbiome project 16S metabarcoding data to detect microalgal-bacterial associations in aquatic environments. We analysed marine and freshwater environments to understand what groups of bacteria are tightly co-occurring with different algal groups in both aquatic environments, to see patterns of interactions, and to evaluate the overall use of co-occurrence networks to infer meaningful algal-bacterial interactions. In line with expectations from co-culturing work, our results show that the phyla Proteobacteria and Bacteroidetes are the major bacterial associates of microalgae and the co-occurring bacteria may be specific to the algal host. From the independent analysis of environments, we also show that sample origin may be an important determinant of these interactions. By unravelling previously established microalgal-bacterial links as well as identifying a range of previously unknown interactions, we show that co-occurrence network analysis is a promising hypothesis-generating framework to study microalgal-bacterial interactions that can guide future research into the functional nature of interactions.

Author(s):  
Vijay Kumar

: Mimosa pudica Linn is an integrated part of Traditional Medicines Systems of India, China, Africa, Korea and America. It has been used from centuries in traditional medicines to cure different diseases like fever, diabetes, constipation, jaundice, ulcers, biliousness, and dyspepsia. It is an important ingredient of wide class of herbal formulations. To assess the scientific evidence for therapeutic potential of Mimosa pudica Linn and to identify the gaps for future research. The available information on the ethno-medicinal uses, phytochemistry, pharmacology and toxicology of Mimosa pudica Linn was collected via a library and electronic searches in Sci-Finder, Pub-Med, Science Direct, Google Scholar for the period, 1990 to 2020. In traditional medicinal systems, variety of ethno-medicinal applications of Mimosa pudica Linn has been noticed. Phytochemical investigation has resulted in identification of 40 well known chemical constituents, among which alkaloids, phenols and flavionoids are the predominant groups. The crude extracts and isolates have exhibited a wide spectrum of in vitro and in vivo pharmacological activities including anti-cancer, anti-inflammation, osteoporosis, neurological disorders, hypertension etc.. To quantify the Mimosa pudica Linn and its formulations, analytical techniques like HPLC and HPTLC has shown dominancy with good range of recovery and detection limit. Mimosa pudica Linn is the well-known herb since an ancient time. The pharmacological results supported some of the applications of Mimosa pudica Linn in traditional medicine systems. Perhaps, the predominance of alkaloids, phenols and flavionoids are responsible for the pharmacological activities the crude extracts and isolates of Mimosa pudica Linn. Further, there is need to isolate and evaluate the active chemical constituents of Mimosa pudica Linn having significant medicinal values. In future, it is important to study the exact mechanism associated with the phytochemicals of Mimosa pudica Linn especially on anti-cancer activities. Notably, toxicity studies on Mimosa pudica Linn are limited which are to be explored in future for the safe application of Mimosa pudica Linn and its formulations.


2020 ◽  
Vol 9 (1) ◽  
pp. 1326-1349
Author(s):  
Siti Nurul Akmal Yusof ◽  
Nor Azwadi Che Sidik ◽  
Yutaka Asako ◽  
Wan Mohd. Arif Aziz Japar ◽  
Saiful Bahri Mohamed ◽  
...  

Abstract Nanofluid is a colloidal mixture consisting of nano-sized particles dispersed in a liquid medium. It improves heat transfer properties and promotes high energy efficiency in a wide spectrum of engineering applications. In recent years, particularly in the automotive industry, the addition of nanofluid in diesel/biodiesel as an additive for ICE has become an attractive approach to promote enhanced combustion efficiency and emission reduction due to their superior thermophysical properties. Many researchers have previously demonstrated that the addition of nanoparticles in diesel/biodiesel fuel improved the overall engine combustion characteristics. As a whole, this study aims to summarize the recent research findings related to the effect of nanoparticles on the fuel properties and engine combustion efficiency. Furthermore, different types of additive blended with varying fuel properties are also compared and discussed. Lastly, the advantages and prospects of using nanofluid as an additive fuel are summarized for future research opportunities.


Author(s):  
Leonardo B. Furstenau ◽  
Bruna Rabaioli ◽  
Michele Kremer Sott ◽  
Danielli Cossul ◽  
Mariluza Sott Bender ◽  
...  

The COVID-19 pandemic has affected all aspects of society. Researchers worldwide have been working to provide new solutions to and better understanding of this coronavirus. In this research, our goal was to perform a Bibliometric Network Analysis (BNA) to investigate the strategic themes, thematic evolution structure and trends of coronavirus during the first eight months of COVID-19 in the Web of Science (WoS) database in 2020. To do this, 14,802 articles were analyzed, with the support of the SciMAT software. This analysis highlights 24 themes, of which 11 of the more important ones were discussed in-depth. The thematic evolution structure shows how the themes are evolving over time, and the most developed and future trends of coronavirus with focus on COVID-19 were visually depicted. The results of the strategic diagram highlight ‘CHLOROQUINE’, ‘ANXIETY’, ‘PREGNANCY’ and ‘ACUTE-RESPIRATORY-SYNDROME’, among others, as the clusters with the highest number of associated citations. The thematic evolution. structure presented two thematic areas: “Damage prevention and containment of COVID-19” and “Comorbidities and diseases caused by COVID-19”, which provides new perspectives and futures trends of the field. These results will form the basis for future research and guide decision-making in coronavirus focused on COVID-19 research and treatments.


2021 ◽  
pp. 1-23
Author(s):  
Benjamin P. Sperry ◽  
Christopher R. Mudge ◽  
Kurt D. Getsinger

Foliar delivery of herbicides is a common means for plant management in aquatic environments. Though this technique is decades old, little is known about vegetative spray retention relative to this application method. A more complete understanding of maximizing herbicide retention could lead to improved plant management while simultaneously decreasing pesticide load in aquatic environments. Therefore, outdoor mesocosm experiments were conducted in 2020 to evaluate the effect of adjuvant type on foliar spray retention in waterhyacinth. Additionally, the effect of carrier volume on spray retention in waterhyacinth, waterlettuce, and giant salvinia was documented. Spray deposition did not differ among the nine adjuvants tested; however, spray retention was reduced 6 to 11% when an adjuvant was excluded from the spray solution. The effect of carrier volume on spray retention in waterhyacinth, waterlettuce, and giant salvinia was also investigated. Decreases in spray retention was most sensitive to increased carrier volume in waterhyacinth, followed by giant salvinia and waterlettuce. Among species, spray retention potential, as determined by intercept estimates, was greatest in waterlettuce and giant salvinia regardless of carrier volume. Asymptotes estimates for waterhyacinth, waterlettuce, and giant salvinia were 33, 46, and 79% spray retention, respectively. In other words, spray retention was the lowest and remained relatively constant at these values for the high carrier volumes tested (935 and 1870 L ha−1), which were likely due to the presence of pubescence on leaves and flatter leaf architecture represented by waterlettuce and giant salvinia compared to the glabrous vertical leaves of waterhyacinth. Future research will evaluate these concepts under field conditions.


2019 ◽  
Vol 33 (2) ◽  
pp. 126-141
Author(s):  
Faten Alshammari ◽  
Jeremy Whaley ◽  
Songyee Hur ◽  
Youn-Kyung Kim

PurposeThe purpose of this paper is to conduct a within-gender analysis and between-gender differences in seeking (personal and interpersonal) and escaping (personal and interpersonal) motivations to attend a non-traditional festival in Saudi Arabia. Specific objectives were: to conduct a within-gender analysis in motivations to attend a non-traditional festival in Saudi Arabia; and to examine between-gender differences in motivations to attend a non-traditional festival in Saudi Arabia.Design/methodology/approachBased on the data collected from 458 attendees at a non-traditional festival in Saudi Arabia, the authors employed network analysis for within-gender analysis and MANOVA and ANOVA for between-gender comparison. The network analysis served two purposes, in that it examined each item’s predictability for each gender, and analyzed the correlations among motivation items within each gender. In addition, the General Linear Model served to compare the male and female groups’ motivations to attend the non-traditional festival. The authors first performed MANOVA for each dimension and then ANOVA for each dimension’s individual items.FindingsWithin-gender analysis reveals that several sets of motivations were associated strongly for both genders. This suggests that Saudi Arabians seem to enjoy entertainment because it projects the festival mood; they want to escape both from home and work and attend the festival to relieve stress by changing their routine pace. However, gender differences were apparent in several other items, especially for the group of women. Between-group comparison analysis shows significant gender differences in several elements of motivation. Overall, personal seeking and escaping were greater for males than females. In contrast, interpersonal seeking was greater for females than males.Research limitations/implicationsEntertainment seems to be a key contributor to the festival mood because entertainment and the festival mood were related closely for both genders. In fact, personal and interpersonal escaping means were greater than personal interpersonal seeking means for both genders. Indeed, opportunities exist to develop non-traditional festivals in the country further. Gender differences were identified in several items of personal seeking and escaping, and interpersonal seeking. With respect to personal seeking, men tend to seek the entertainment, festival mood and the event’s uniqueness more than do women, a finding that their higher means in personal escaping supported. It is clear that men view the festival as a way to enjoy themselves to escape from their jobs and daily stress to a greater degree than do their female counterparts. Women are more likely to seek interpersonal experiences in that they are more likely to enjoy the festival because it offers the opportunity to meet new people and spend quality time with family and friends. This study has several limitations, leading to suggestions for future research. Because seeking and escaping motivations have been used relatively little in the festival setting, future researchers should develop a valid scale of personal and interpersonal seeking and escaping motivations specifically for festivals employing both qualitative and quantitative methods. Second, while the data were collected at a single non-traditional festival, future research can use multiple sites to increase the ability to generalize the findings. Third, although this study was limited to Saudi Arabia, further research can apply seeking and escaping motivations, both at the personal and interpersonal levels, to other cultures to extend the applicability of the framework used in this study.Practical implicationsNon-traditional festival managers need to focus on an atmosphere that provides festivities, as many people in the Saudi Arabian culture appear to be escaping from their everyday lives to enjoy themselves and with family and friends. To appeal to male workers, festival organizers and managers need to advertise and market the events’ mood and liveliness overall with photos of workers leaving the office free of stress and looking forward to attending an event. To appeal to women who desire unique experiences that a variety of forms of entertainment provide, event managers must ensure that the entertainment is innovative and creative, and differs from what other festivals provide to attract more female attendees. Also, festival planners must focus on events that incorporate the family unit and promote the opportunity to meet new people to appeal to women in Saudi Arabia.Originality/valueThis is the first study to examine gender differences in festival motivations in Saudi Arabia. The relaxation of the historically strict and conservative cultural values, coupled with the country’s desire to develop its tourism and event sector, provides an ideal opportunity for future research. The authors hope that this research will stimulate further interest in the country with the goal to develop and market its tourism sector and products on the world’s stage.


2005 ◽  
Vol 14 (4) ◽  
pp. 339 ◽  
Author(s):  
Stefan H. Doerr ◽  
Artemi Cerdá

Fire affects entire ecosystems – their flora, fauna, the atmosphere and soil. Research on the effects of fire to date has focussed primarily on the former three, whereas effects on the soil system have seen less attention. Burning and resulting post-fire environmental conditions can alter the functioning of soils physically (e.g. aggregate stability, pore size, distribution, water repellency and runoff response), chemically (e.g. nutrient availability, mineralogy, pH and C : N ratios) and biologically (e.g. biomass productivity, microbial composition and carbon sequestration). These fire-induced alterations have typically been examined in isolation by researchers in separate disciplines despite the sometimes strong relationship between some of these physical, chemical and biological effects. This special issue brings together studies from diverse disciplines, focussing on a wide spectrum of fire effects on the soil system. Here we aim to summarise, evaluate and set into context some of the new insights arising from these studies. A case is made for enhanced cross-disciplinary collaboration and the use of multi-scale research approaches in order to meet existing and future research challenges in this diverse field.


2018 ◽  
Vol 32 (2) ◽  
pp. 425-462 ◽  
Author(s):  
Ruggero Sainaghi ◽  
Rodolfo Baggio ◽  
Paul Phillips ◽  
Aurelio G. Mauri

Purpose This paper aims to provide a review of hotel performance within the hospitality and tourism research domain. The authors use network analysis to examine two research questions. The first relates to ascertaining general trends within the hotel performance literature, and the second focuses on identifying the salient streams and sub-topics. Design/methodology/approach Articles were selected according to three criteria: keywords, journals and year of publication. The analysis embraces 20 years (1996-2015). These choices assure a wide coverage of the literature. Using these three criteria, the sample includes 1,155 papers. For the analysis, the authors created a network of papers designated as nodes, and the citations among the papers as links. A network approach recognizes the internal structure of the network by identifying groups of nodes (papers) that are more densely connected between themselves than to other nodes within the network (modules, clusters or communities). Findings The authors found 761 papers that were “connected” studies within the network. By contrast, 34 per cent of the sample (394 papers) consists of “unconnected” studies. Excluding outliers, the net sample was 734 articles. The authors identify 14 clusters, which they break down into several sub-topics. The authors conclude by providing some conclusions regarding trends and future research directions. With regards to salient topics, cross-citation and network analysis provide a detailed picture of where the literature comes from and where it currently stands. Conclusions are articulated at the theoretical and empirical levels. Originality/value Compared with previous hotel performance reviews, the approach followed by this study enables the discovery of an analytical research map, which is able to identify both clusters and sub-topics populating each segment. Researchers are able to position their work and identify issues that are in growth and decline.


Author(s):  
Eun-Joo Kim ◽  
Ji-Young Lim ◽  
Geun-Myun Kim ◽  
Seong-Kwang Kim

Improving nursing students’ subjective happiness is germane for efficiency in the nursing profession. This study examined the subjective happiness of nursing students by applying social network analysis (SNA) and developing a strategy to improve the subjective happiness of nursing. The study adopted a cross sectional survey to measure subjective happiness and social network of 222 nursing students. The results revealed that the centralization index, which is a measure of intragroup interactions from the perspective of an entire network, was higher in the senior year compared with the junior year. Additionally, the indegree, outdegree, and centrality of the social network of students with a high level of subjective happiness were all found to be high. This result suggests that subjective happiness is not just an individual’s psychological perception, but can also be expressed more deeply depending on the subject’s social relationships. Based on the study’s results, to strengthen self-efficacy and resilience, it is necessary to utilize strategies that activate group dynamics, such as team activities, to improve subjective happiness. The findings can serve as basic data for future research focused on improving nursing students’ subjective happiness by consolidating team-learning social networks through a standardized program approach within a curriculum or extracurricular programs.


Psichologija ◽  
2005 ◽  
Vol 31 ◽  
pp. 86-100
Author(s):  
Rita Rekašiūtė-Balsienė

Daugelio tyrimų rezultatai rodo, kad organizacijos klimatas ir jos veiklos rezultatai yra susiję. Organizacijos klimato matavimas gali būti atspirties taškas planuojant veiklos tobulinimo, siekiant didesnio efektyvumo, pokyčius. Straipsnyje pristatytos trys organizacijos klimato teorijų grupės ir atliktas tyrimas, siekiant aprašyti Lietuvos verslo organizacijų klimatą. Tyrimo tikslas – įvertinti Lietuvos verslo organizacijų klimatą taikant tam sukurtą metodiką. Tyrimui keliami uždaviniai: 1) parengti organizacijos klimato vertinimo metodiką; 2) išanalizuoti organizacijos klimato ypatybes, būdingas Lietuvos verslo organizacijoms. Gauti rezultatai rodo, kad Lietuvos verslo organizacijų klimatas turi bendrų ypatumų: geriausiai yra vertinama organizacijos svarba darbuotojams (didžiavimasis organizacija), darbuotojų pastangos ir tarpusavio santykiai bei pagarba, o blogiausiai – darbuotojų veiklos ir pastangų įvertinimas bei darbo organizavimas. Sukurta metodika patikrinta tiriant Lietuvos verslo organizacijas. Ji leidžia įvertinti bei aprašyti organizacijos klimatą ir gali būti pagrindas aiškinantis, kokia yra organizacijos būklė. ORGANIZATIONAL CLIMATE ASSESSMENT POSSIBILITIES IN BUSINESS ORGANIZATIONSRita Rekašiūtė-Balsienė SummaryOrganizational climate has been widely discussed in the literature since the concept of social climate was proposed. They perceived organizational climate as a set of properties of the working environment which can be measured. In the article we present three set of theories of organizational climate concepts, which were found in the literature.The wide spectrum of organizational climate and performance surveys suggests that there are relationship between the climate dimensions and all kind of organizational performance indicators. It is suggested, that for a plan of activities for improving effectiveness of all organization may be used climate surveys.The purpose of this survey is to evaluate organizational climate is Lithuanian business organizations using the questionnaire which was created by the author of the article.Sample: 6 Lithuanian organizations from the service business sector, total of 591 employees. All organizations are among the firs seventh leaders of their practice field.Method: Organizational climate questionnaire (constructed by author of the article) was used in this survey. Factorial analysis distinguishes eight factors (scales): evaluations of employee attempts and performance; interrelations and respect; flexibility and quality of organization performance; employee struggle; goals knowledge; organization magnitude; cooperation; work organization. The research has been carried out in 2003–2004.Results of this survey shows, that all organizations have common peculiarities of organizational climate. Perceived as the best organizational climate aspects are organization magnitude, employee struggle, interrelations and respect; perceived as the worst organizational climate aspects are evaluation of employee attempts and performance and work organization. There was found significant differences in perceived organization conditions between managers and employees and between business departments and business support departments, what request more in depth survey. Organizational climate of two organizations are described in detail. It is suggested, that created questionnaire can be used to asses organizational climate and be useful tool for the organizational development practitioner and researcher. Practical implications and suggestions for future research are proposed.


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