442 research outputs found
Microbial interactions and community assembly at microscales
No full textIn most environments, microbial interactions take place within microscale cell aggregates. At the scale of these aggregates (∼100μm), interactions are likely to be the dominant driver of population structure and dynamics. In particular, organisms that exploit interspecific interactions to increase ecological performance often co-aggregate. Conversely, organisms that antagonize each other will tend to spatially segregate, creating distinct micro-communities and increased diversity at larger length scales. We argue that, in order to understand the role that biological interactions play in microbial community function, it is necessary to study microscale spatial organization with enough throughput to measure statistical associations between taxa and possible alternative community states. We conclude by proposing strategies to tackle this challenge
Dr. Monti Datta – Faculty Author Interview
No full textDr. Monti Datta, Assistant Professor of Political Science, discusses his forthcoming new book, Anti-Americanism and the Rise of World Opinion. Drawing from a wealth of research data, interviews and surveys of social media, this book directly examines pro- and anti-American views and asks what we can learn about the nature and impact of world opinion. By treating anti-Americanism as a case study of public opinion at work, Professor Datta reveals how we can better understand the relationship between global citizens and their political leaders, and concludes that anti-Americanism does in fact substantially impact US security, as well as its economic and political interests
Tapping Economies of Scale and Scope in Consumer Cooperation - A Case Analysis of Possible Cooperation among selected Cooperatives
No full textBecause of its narrow and negative perspective of safeguarding the interests of only poor consumers against unethical practices of the private traders, consumer cooperation in India seems to have failed, except probably in some isolated pockets. A number of social welfare functions like poverty alleviation and public distribution of essential items of consumption have been imposed on them at the cost of their basic economics. With the basic micro and macro-economic rationale for consumer cooperatives as a positive form of economic organization being lost sight of, they seem to be facing enormous problems both historically as well as currently in a era of economic liberalization. Their worries seem to have been compounded with the threat of impending competition from large private enterpriss - both domestic and foreign, which highlights the need for evolving strategies to rectivy their systemic weaknesses and tackling the competition head on. This case has attempted to document just such an initiative through a round table conference with several doyens of the consumer cooperative movement in India such as Warana Bazar and Amalsad Mandali as well as some fledging consumer cooperatives from West Bengal which are already in existence for some time or contemplating entry into this field. The roundtable conference organized in the spirit of Cooperation among Cooperatives attempted to evolve strategies to capture economies of scale and scope in order to take on the competition, as well as to facilitate dissemination of ideas and information across the country.
Microbial community structure and dynamics on patchy landscapes
No full textThesis: Ph. D., Massachusetts Institute of Technology, Computational and Systems Biology Program, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 139-156).Microbes are tiny metabolic engines with large-scale effects on industry, the environment, and human health. Understanding how the micron-scale actions (and interactions) of individual microbes give rise to macro-scale consequences remains a major challenge in microbial ecology. However, for the most part, studies employ coarsegrained sampling schemes, which average over the heterogeneous microscopic structure of microbial communities. This has limited our ability to establish mechanistic links between dynamics occurring across these disparate spatial scales. However, such links are critical for (a) making sense of the tremendous extant microbial diversity on Earth, and (b) predicting how perturbations (e.g., global climate change) may influence microbial diversity and function. In this thesis, I characterize the structure and dynamics of wild bacterial populations in the ocean at spatial scales of tens of microns. I then employ a simple, two-strain laboratory model system to link (cooperative) inter-species interactions at local scales to emergent properties at larger scales, focusing on spatially connected meta-communities undergoing range expansions into new territory. This work encompasses diverse environments (ranging from well-mixed communities in the laboratory to individual crustaceans) and approaches (including mathematical modeling, highthroughput sequencing, and traditional microbiological experiments). Altogether, we find that the microscale environment inhabited by a microbe - that is, "what the neighborhood is like" and "who lives next to whom" - shapes the structure and dynamics of wild microbial populations at local scales. Moreover, these local interactions can drive patterns of biodiversity and function, even at spatial scales much larger than the length of an individual cell. Thus, our work represents a small step toward developing mechanistic theories for how microbes shape our planet's ecosystems.by Manoshi Sen Datta.Ph. D
Bacterial cheating drives the population dynamics of cooperative antibiotic resistance plasmids
No full textInactivation of β‐lactam antibiotics by resistant bacteria is a ‘cooperative’ behavior that may allow sensitive bacteria to survive antibiotic treatment. However, the factors that determine the fraction of resistant cells in the bacterial population remain unclear, indicating a fundamental gap in our understanding of how antibiotic resistance evolves. Here, we experimentally track the spread of a plasmid that encodes a β‐lactamase enzyme through the bacterial population. We find that independent of the initial fraction of resistant cells, the population settles to an equilibrium fraction proportional to the antibiotic concentration divided by the cell density. A simple model explains this behavior, successfully predicting a data collapse over two orders of magnitude in antibiotic concentration. This model also successfully predicts that adding a commonly used β‐lactamase inhibitor will lead to the spread of resistance, highlighting the need to incorporate social dynamics into the study of antibiotic resistance.National Science Foundation (U.S.). Graduate Research Fellowship (Grant 0645960)Massachusetts Institute of Technology. Undergraduate Research Opportunities ProgramAmerican Society for Engineering Education. National Defense Science and Engineering Graduate Fellowshi
Range expansion promotes cooperation in an experimental microbial metapopulation
No full textNatural populations throughout the tree of life undergo range expansions in response to changes in the environment. Recent theoretical work suggests that range expansions can have a strong effect on evolution, even leading to the fixation of deleterious alleles that would normally be outcompeted in the absence of migration. However, little is known about how range expansions might influence alleles under frequency- or density-dependent selection. Moreover, there is very little experimental evidence to complement existing theory, since expanding populations are difficult to study in the natural environment. In this study, we have used a yeast experimental system to explore the effect of range expansions on the maintenance of cooperative behaviors, which commonly display frequency- and density-dependent selection and are widespread in nature. We found that range expansions favor the maintenance of cooperation in two ways: (i) through the enrichment of cooperators at the front of the expanding population and (ii) by allowing cooperators to “outrun” an invading wave of defectors. In this system, cooperation is enhanced through the coupling of population ecology and evolutionary dynamics in expanding populations, thus providing experimental evidence for a unique mechanism through which cooperative behaviors could be maintained in nature.National Cancer Institute (U.S.) (Cancer Center Support Grant P30CCA14051)United States. Dept. of Defense (National Defense Science and Engineering Graduate Fellowship Program)MIT Department of Physics Pappalardo Program (Fellowship)Massachusetts Institute of Technology. Undergraduate Research Opportunities ProgramNational Institutes of Health (U.S.) (R00 Pathways to Independence Award GM085279-02)National Science Foundation (U.S.) (Career Award PHY-1055154)Pew Charitable Trusts (Fellowship 2010-000224-007)Alfred P. Sloan Foundation (Fellowship BR2011-066)National Institutes of Health (U.S.) (New Innovator Award DP2
Microbial interactions lead to rapid micro-scale successions on model marine particles
No full textIn the ocean, organic particles harbour diverse bacterial communities, which collectively digest and recycle essential nutrients. Traits like motility and exo-enzyme production allow individual taxa to colonize and exploit particle resources, but it remains unclear how community dynamics emerge from these individual traits. Here we track the taxon and trait dynamics of bacteria attached to model marine particles and demonstrate that particle-attached communities undergo rapid, reproducible successions driven by ecological interactions. Motile, particle-degrading taxa are selected for during early successional stages. However, this selective pressure is later relaxed when secondary consumers invade, which are unable to use the particle resource but, instead, rely on carbon from primary degraders. This creates a trophic chain that shifts community metabolism away from the particle substrate. These results suggest that primary successions may shape particle-attached bacterial communities in the ocean and that rapid community-wide metabolic shifts could limit rates of marine particle degradation.American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.) (CAREER Award PHY-1055154)European Research Council (Starting Grant 336938)National Science Foundation (U.S.). Division of Ocean Sciences (Award 14359930
Aspek Sosiologi Pengarang Pada Struktur Batin Puisi Watashi Ga Ichiban Kirei Datta Toki
No full textAbstrak
Penelitian ini bertujuan untuk mengetahui hubungan aspek sosiologi pengarang dengan struktur batin puisi Watashi ga Ichiban Kirei Datta Toki Karya Ibaragi Noriko. Penelitian ini menggunakan metode deskriptif analisis, dengan pendekatan sosiologi pengarang oleh Wellek dan Warren (1994). Penelitian ini dilakukan dengan mendeskripsikan objek penelitian kemudian menganalisis hubungan aspek sosiologi pengarang dengan struktur batin puisi. Hasil penelitian ini adalah terdapat hubungan aspek sosiologi pengarang dengan struktur batin puisi, yaitu pada aspek status sosial pengarang dengan tema dan aspek latar belakang sosial budaya pengarang dengan amanat. Dari hasil penelitian tersebut, dapat diketahui bahwa puisi Watashi ga Ichiban Kirei Datta Toki ditulis oleh Ibaragi Noriko berdasarkan peristiwa yang terjadi dalam hidupnya.
Kata Kunci : puisi, struktur batin, sosiologi pengarang
Abstract
This research aims to determine the relationship of the sociological aspects of the author with the inner structure of the poetry Watashi ga Ichiban Kirei Datta Toki by Ibaragi Noriko. This research uses descriptive analysis method, with the author\u27s sociology approach by Wellek and Warren (1994). This research was conducted by describing the object of research then analyzing the relationship of the sociological aspects of the author with the inner structure of the poetry. The result of this research is that there is a relationship between the sociological aspects of the author with the inner structure of poetry, namely on the aspect of the author\u27s social status with the theme and aspect of the author\u27s socio-cultural background with the mandate. From the results of this research, it can be seen that the poetry Watashi ga Ichiban Kirei Datta Toki was written by Ibaragi Noriko based on events that occurred in his life.
Keywords : poetry, inner structure, author\u27s sociolog
Cyana arorai Volynkin, N. Singh, Kirti & Datta 2020, nom. nov.
No full textCyana arorai Volynkin, N. Singh, Kirti & Datta, nom. nov. (Figs 15–19, 168, 169, 241, 242) = Chionaema tripunctata Rothschild, 1936, The Annals and magazine of natural history (10) 17: 487 (Type locality: “ Aberdeen, Andaman Islands”), nec. Reich, 1935. Type material examined. Holotype (by monotypy) (Fig. 17): ♀, handwritten label “ Aberdeen, Andamans” / hand- written label “ Chionaema tripunctata Type Rothsch.” / handwritten label “Nr. bianca, but has 3 spots” / printed label “Rothschild Bequest B.M. 1939–1” / printed round label with a red circle “Type” / printed label with a unique identifier “NHMUK010402088” (Coll. NHMUK). Other material examined. THE ANDAMAN AND NICOBAR ISLANDS: 1 ♀, Andaman Isles ♀ / Moore Coll. 94–106, slide NHMUK010314603 Volynkin (Coll. NHMUK); 2 ♂, 3 ♀, India, M. Andaman, Karmatang, 1.5 km E, 12,5072°N, 92,5610°E, 17–22.VIII.2001, leg. Jan-Peter Rudloff, coll. Dr. R. Brechlin, slides MWM 33907 (♂), MWM 33908 (♀), MWM 35680 (♀) Volynkin (Coll. MWM / ZSM); 2 ♂, 4 ♀, India, S. Andaman, Port Blair—Mt. Harriet, 11,4321°N, 92,4403°E, 23–24.VIII.2001, leg. Jan-Peter Rudloff, coll. Dr. R. Brechlin, slides MWM 34601 (♂), MWM 34602 (♀) Volynkin (Coll. MWM / ZSM); 1 ♂, 2 ♀, India, Andaman Islands, South Anda- man—Bambooflat (Rainfor.), 11°42’82”N, 092°42’02”E, 27–28.XI.2000, leg. J.P. Rudloff, slide MWM 35681 (♂) Volynkin (Coll. MWM / ZSM); 1 ♂, India, Andaman Isl., South Andaman, Wandoor, Port Blair, 1–2.III.1998, leg. A. Kamenev & V. Siniaev, ex coll. Dr. A. Schintlmeister, slide MWM 34564 (♂) Volynkin (Coll. MWM / ZSM); 1 ♂, Andaman & Nicobar Islands, South Andaman, Chidiyatapu, 29.XII.17, leg. H.S. Datta (Coll. NZCZSI). Etymology. The replacement name is dedicated to G.S. Arora, author of the basic publication on the fauna of the Andaman and Nicobar Islands. Remark. The taxon tripunctata Reich, 1935 was described under the genus Lyclene. Here we transfer it to the genus Cyana and synonymize with C. detrita (see above). Thus, at present there are two Cyana taxa with the name tripunctata, so tripunctata Rothschild, 1936 becomes a junior secondary homonym of tripunctata Reich, 1935. Hence, we introduce the replacement name arorai nom. nov. for tripunctata Rothschild, 1936. Diagnosis. Forewing length is 12.5–15 mm in males and 17–18 mm in females. Cyana arorai is a polymorphic species, significantly variable in size. Cyana arorai is similar externally to C. carmina (Figs 13, 14), but differs by its arcuate antemedial line (that is oblique in C. carmina) and larger black discal spots. In females of C. arorai a third, posterior black spot may be developed (Figs 16, 17), what is unusual for the C. insularis group. The female genitalia of C. arorai are very similar to those of C. carmina (Figs 239, 240), but differ by the more heavily sclerotized cervix bursae having narrower longitudinal folds, and the lateral band-like signum being more weakly sclerotized subanteriorly with its anterior end strongly broadened. Distribution. Endemic of the Andaman Islands. The records of C. bianca (male) and C. coccinea (female) for the Andaman Islands (Hampson 1900; Draudt 1914; Arora 1983) belong to C. arorai.Published as part of Singh, Navneet, Volynkin, Anton V., Kirti, Jagbir Singh, Datta, Harvinder Singh & Ivanova, Maria S., 2020, A review of the genus Cyana Walker, 1854 from India, with descriptions of five new species and three new subspecies (Lepidoptera: Erebidae: Arctiinae: Lithosiini), pp. 1-93 in Zootaxa 4738 (1) on page 10, DOI: 10.11646/zootaxa.4738.1.1, http://zenodo.org/record/367243
Cross-Kingdom Chemical Communication Drives a Heritable, Mutually Beneficial Prion-Based Transformation of Metabolism
No full textIn experimental science, organisms are usually studied in isolation, but in the wild they compete and cooperate in complex communities. We report a system for cross-kingdom communication by which bacteria heritably transform yeast metabolism. An ancient biological circuit blocks yeast
from using other carbon sources in the presence of glucose. [GAR[superscript +]], a protein-based epigenetic element, allows yeast to circumvent this glucose repression and use multiple carbon sources in the presence of glucose. Some bacteria secrete a chemical factor that induces [GAR[superscript +]]. [GAR[superscript +]] is advantageous to bacteria because yeast cells make less ethanol, and is advantageous to yeast because their growth and long-term viability is improved in complex carbon sources. This crosskingdom communication is broadly conserved, providing a compelling argument for its adaptive value. By heritably transforming growth and survival strategies in response to the selective pressures of life in a biological community, [GAR[superscript +]] presents a unique example of Lamarckian inheritance.G. Harold and Leila Y. Mathers FoundationHoward Hughes Medical Institut
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