Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
A new species of the fungus-farming ant genus Mycetagroicus Brand?o & Mayhé-Nunes (Hymenoptera, Formicidae, Attini)
Brand?o, Carlos Roberto Ferreira;Mayhé-Nunes, Antonio José;
Revista Brasileira de Entomologia , 2008, DOI: 10.1590/S0085-56262008000300006
Abstract: the fungus-farming ant genus mycetagroicus brand?o & mayhé-nunes was proposed based on three species from the brazilian "cerrado": m. cerradensis, m. triangularis and m. urbanus. here we describe a new species of attini ant of the genus mycetagroicus, m. inflatus n. sp., based on two workers collected in eastern pará state, brazil. a new key for species identification, comments on differences among species and new geographical distribution data are furnished.
Molecular phylogeny of bark and ambrosia beetles reveals multiple origins of fungus farming during periods of global warming  [cached]
Jordal Bjarte H,Cognato Anthony I
BMC Evolutionary Biology , 2012, DOI: 10.1186/1471-2148-12-133
Abstract: Background Fungus farming is an unusual life style in insects that has evolved many times in the wood boring weevils named ‘ambrosia beetles’. Multiple occurrences of this behaviour allow for a detailed comparison of the different origins of fungus farming through time, its directionality, and possible ancestral states. We tested these hypotheses with a phylogeny representing the largest data set to date, nearly 4 kb of nucleotides from COI, EF-1α, CAD, ArgK, 28S, and 200 scolytine taxa. Results Phylogenetic analyses using Bayesian or parsimony approaches placed the root of Scolytinae close to the tribe Scolytini and Microborus, but otherwise indicated low resolution at older nodes. More recent clades were well resolved, including ten origins of fungus farming. There were no subsequent reversals to bark or phloem feeding in the fungus farming clades. The oldest origin of fungus farming was estimated near 50 Ma, long after the origin of Scolytinae (100-120 Ma). Younger origins included the species rich Xyleborini, dated to 21 Ma. Sister group comparisons and test of independence between traits indicated that neither gregarious larval feeding nor regular inbreeding by sibling mating was strongly correlated with the origin of fungus farming. Conclusion Origins of fungus farming corresponded mainly with two periods of global warming in the Cenozoic era, which were characterised by broadly distributed tropical forests. Hence, it seems likely that warm climates and expanding tropical angiosperm forests played critical roles in the successful radiation of diverse fungus farming groups. However, further investigation will likely reveal additional biological factors that promote fungus farming.
A mixed community of actinomycetes produce multiple antibiotics for the fungus farming ant Acromyrmex octospinosus
J?rg Barke, Ryan F Seipke, Sabine Grüschow, Darren Heavens, Nizar Drou, Mervyn J Bibb, Rebecca JM Goss, Douglas W Yu, Matthew I Hutchings
BMC Biology , 2010, DOI: 10.1186/1741-7007-8-109
Abstract: In order to test these possibilities we isolated bacteria from a geographically distinct population of A. octospinosus and identified a candicidin-producing Streptomyces species, which suggests that they are common mutualists of attine ants, most probably recruited from the environment. We also identified a Pseudonocardia species in the same ant colony that produces an unusual polyene antifungal, providing evidence for co-evolution of Pseudonocardia with A. octospinosus.Our results show that a combination of co-evolution and environmental sampling results in the diversity of actinomycete symbionts and antibiotics associated with attine ants.Fungiculture in the insect world is practised by ants, termites, beetles and gall midges [1]. The best-characterized examples are the attine ants, which are endemic to South and Central America and to the southern USA. The ancestor of these ants evolved the ability to cultivate fungus as a food source around 50 million years ago, leading to the monophyletic tribe Attini, which number 12 genera with more than 230 species. The genera Acromyrmex and Atta (40 species) evolved 8-12 million years ago and form a branch of the higher attines, also known as leaf-cutting ants, which are characterized by large colonies of up to several million individuals [2]. Like the other leaf-cutting ants, the well-studied species Acromyrmex octospinosus forms a mutualism with a single basidiomycete fungus (Agaricales: Lepiotaceae: Leucocoprineae) Leucoagaricus gongylophorus in which they exchange food as well as protection and transport services [3].The mutualistic fungal garden can be parasitized by a variety of other fungi [4] but the major pathogen of leaf-cutting ant fungal gardens is a necrotrophic fungus (Ascomycota: anamorphic Hypocreales) in the genus Escovopsis [5]. Around 25% of the gardens in Panamanian ant colonies contain Escovopsis which feed on the fungal cultivar and can destroy fungal gardens, leading to the collapse of the colony [6].
Diversity of Termitomyces Associated with Fungus-Farming Termites Assessed by Cultural and Culture-Independent Methods  [PDF]
Huxley M. Makonde, Hamadi I. Boga, Zipporah Osiemo, Romano Mwirichia, J. Benjamin Stielow, Markus G?ker, Hans-Peter Klenk
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056464
Abstract: Background Fungus-cultivating termites make use of an obligate mutualism with fungi from the genus Termitomyces, which are acquired through either vertical transmission via reproductive alates or horizontally transmitted during the formation of new mounds. Termitomyces taxonomy, and thus estimating diversity and host specificity of these fungi, is challenging because fruiting bodies are rarely found. Molecular techniques can be applied but need not necessarily yield the same outcome than morphological identification. Methodology Culture-dependent and culture-independent methods were used to comprehensively assess host specificity and gut fungal diversity. Termites were identified using mitochondrial cytochrome oxidase II (COII) genes. Twenty-three Termitomyces cultures were isolated from fungal combs. Internal transcribed spacer (ITS) clone libraries were constructed from termite guts. Presence of Termitomyces was confirmed using specific and universal primers. Termitomyces species boundaries were estimated by cross-comparison of macromorphological and sequence features, and ITS clustering parameters accordingly optimized. The overall trends in coverage of Termitomyces diversity and host associations were estimated using Genbank data. Results and Conclusion Results indicate a monoculture of Termitomyces in the guts as well as the isolation sources (fungal combs). However, cases of more than one Termitomyces strains per mound were observed since mounds can contain different termite colonies. The newly found cultures, as well as the clustering analysis of GenBank data indicate that there are on average between one and two host genera per Termitomyces species. Saturation does not appear to have been reached, neither for the total number of known Termitomyces species nor for the number of Termitomyces species per host taxon, nor for the number of known hosts per Termitomyces species. Considering the rarity of Termitomyces fruiting bodies, it is suggested to base the future taxonomy of the group mainly on well-characterized and publicly accessible cultures.
A Single Streptomyces Symbiont Makes Multiple Antifungals to Support the Fungus Farming Ant Acromyrmex octospinosus  [PDF]
Ryan F. Seipke, J?rg Barke, Charles Brearley, Lionel Hill, Douglas W. Yu, Rebecca J. M. Goss, Matthew I. Hutchings
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0022028
Abstract: Attine ants are dependent on a cultivated fungus for food and use antibiotics produced by symbiotic Actinobacteria as weedkillers in their fungus gardens. Actinobacterial species belonging to the genera Pseudonocardia, Streptomyces and Amycolatopsis have been isolated from attine ant nests and shown to confer protection against a range of microfungal weeds. In previous work on the higher attine Acromyrmex octospinosus we isolated a Streptomyces strain that produces candicidin, consistent with another report that attine ants use Streptomyces-produced candicidin in their fungiculture. Here we report the genome analysis of this Streptomyces strain and identify multiple antibiotic biosynthetic pathways. We demonstrate, using gene disruptions and mass spectrometry, that this single strain has the capacity to make candicidin and multiple antimycin compounds. Although antimycins have been known for >60 years we report the sequence of the biosynthetic gene cluster for the first time. Crucially, disrupting the candicidin and antimycin gene clusters in the same strain had no effect on bioactivity against a co-evolved nest pathogen called Escovopsis that has been identified in ~30% of attine ant nests. Since the Streptomyces strain has strong bioactivity against Escovopsis we conclude that it must make additional antifungal(s) to inhibit Escovopsis. However, candicidin and antimycins likely offer protection against other microfungal weeds that infect the attine fungal gardens. Thus, we propose that the selection of this biosynthetically prolific strain from the natural environment provides A. octospinosus with broad spectrum activity against Escovopsis and other microfungal weeds.
Sujatha R,Bandaru Rama krishna Rao
Indian Journal of Computer Science and Engineering , 2011,
Abstract: For any information to be organized, taxonomy is essential. Taxonomy plays a very important role for information and content management. Also it helps in searching of content. The most common method forconstructing taxonomy was the manual construction. As the information available today is huge, constructing taxonomy for such information manually was time consuming and maintenance was difficult. This paperpresents an overview of various taxonomy construction techniques available for easier construction of taxonomy or generating taxonomy automatically. Also this paper describes the advantages and disadvantages of each technique used.
Analysis of Goat Farming on Integrated Farming System in Banyumas  [cached]
NN Hidayat
Journal of Animal Production , 2007,
Abstract: The objective of this research were : 1) to find out the income generated from goat farming and its contribution to farmer income in several farming combination, 2) to find out the economic efficiency in goat farming with paddy and fish production, 3) to determine factors affecting level of production and income in different farming system, partially and aggregately, and 4) to determine the best combination of farming which generated maximum income. Household farmer survey method was performed to conduct this research. Farming model chosen in this research was partial and average aggregate. Cobb-Douglas function were chosen to predict functional relationship. Result stated from this research were : 1) goat farming has a significant contribution in integrated farming system, 2) integrated farming (goat and paddy, goat and fish, and goat, fish and paddy) in Banyumas district was economically efficient. 3) partially, factor affecting production level in goat farming was number of goat owned (P<0.01), factor affecting paddy production were urea application and number of land owned (P<0.01), TSP application (P<0.05) and man power (P<0.10). Furthermore, factor affecting fish farming were feed, breed and number of land owned (P<0.01); 4) aggregately, factor affecting integrated farming I were urea application and number of land owned (P<0.01), feed and number of land owned (P<0.01), number of goat owned (P<0.10) integrated farming II, where as in integrated farming III were number of paddy land area and breed (P<0.01) also number of goat owned (P<0.10); 5) integrated farming III (goat, paddy and fish farming) gave the highest profit, which gave Rp 6.219.283,81 with relatively high efficiency. Therefore, goat farming could be an alternative solution to be developed in integrated farming and could be combined with other farming activities such as paddy and fish farming. (Animal Production 9(2): 105-110 (2007) Key Words : Goat, income, economic efficiency, survey, contribution, integrated farming
Dr R.D. Deshmukh
Indian Streams Research Journal , 2012,
Abstract: India is a country of farming. Cows and buffaloes are not only infrastructure part of farm but cow & buffaloes are important part of the life of human beings. Milk is total food of human lives. Today the population of India is near about 121 crores and each with farming, In Maharashtra small farmer having four to five acres of land is on large-scale. They are not only depending on farming but also on milk production business i.e. dairy farming. Therefore it is necessary to select dairy farm is as joint business with farming
Alley Farming in Thailand  [PDF]
Elizabeth Adebola Ogunlana,Athapol Noomhorm,Teerapol Silakul
Sustainability , 2010, DOI: 10.3390/su2082523
Abstract: Poverty alleviation and environmental preservation are very important issues to many governments. Alley farming is beneficial to the environment because it conserves soil and sustains yields over time. Specifically, alley farming reduces soil erosion, which is a major problem in Thailand. Alley farming was conducted on a farmer’s field at Khaokwan Thong, a village in Uthaithani Province, Northern Thailand. We did a two-by-two factorial with and without alley farming, and with and without fertilizer. From this study, we observed that the two species used, Leucaena leucocephala and Acacia auriculiformis, grow well in Thailand, and that alley farming is suitable for Thailand. Few Thai farmers have heard about alley farming. However, it is nevertheless useful to know that there is potential for alley farming in Thailand using the two species. These plants, based upon the diameter and height measurements provided, grew well.
Taxonomy of Stock Market Indices  [PDF]
Giovanni Bonanno,Nicolas Vandewalle,Rosario N. Mantegna
Quantitative Finance , 2000, DOI: 10.1103/PhysRevE.62.R7615
Abstract: We investigate sets of financial non-redundant and nonsynchronously recorded time series. The sets are composed by a number of stock market indices located all over the world in five continents. By properly selecting the time horizon of returns and by using a reference currency we find a meaningful taxonomy. The detection of such a taxonomy proves that interpretable information can be stored in a set of nonsynchronously recorded time series.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.