scholarly journals The Life-cycle of Bacteria. Alternate Asexual and Autogamic Phases

1928 ◽  
Vol 27 (4) ◽  
pp. 379-395 ◽  
Author(s):  
F. H. Stewart
Keyword(s):  
Life Cycle ◽  
Food Supply ◽  
Colony Formation ◽  
Culture Medium ◽  
Adaptive Variation ◽  
Strain Mode ◽  
Papilla Formation ◽  
Homozygous Strain ◽  
New Crop ◽  
Mode A

I. Life-Cycle. Colony Formation, Sporing, Papilla Formation.If any bacterium is sown in the usual way from a fluid suspension on to a plate of suitable culture medium, colonies arise from the multiplication of single bacteria. These colonies grow at their margins ar a rate roughly constant for the species. When the colony has reached a certain size, which is again roughly constant for the species, it ceases to grow or continues growing very slowly. Thus for example colonies of streptococci grow to 1 mm. in diameter, those of coliforms to 3 or 6 mm. The colonies do not continue to grow until they have covered the whole plate. This limitation of growth is not due to the using up of the food supply or to the drying of the medium, since, if a second sowing of the same bacterium is made between the arrested colonies, a new crop of colonies arises.1 Twort (1907) obtained lactose fermenting variants ofB. typhosusafter prolonged growth in this sugar. These variations do not however occur frequently and regularly. They are probably examples of mutation from a homozygous strain (Mode A above).2 The variations mentioned take place in culture where their origin from papillae can be seen. It is likely that exaltation of virulence is an adaptive variation of the same kind occurring in a host.

scholarly journals Sustainable product-package design in a food supply chain: A multi-criteria life cycle approach

2018 ◽  
Vol 32 (2) ◽  
pp. 85-101 ◽  
Author(s):  
Jafar Rezaei ◽  
Athanasios Papakonstantinou ◽  
Lori Tavasszy ◽  
Udo Pesch ◽  
Austin Kana
Keyword(s):  
Supply Chain ◽  
Life Cycle ◽  
Food Supply ◽  
Life Cycle Approach ◽  
Food Supply Chain ◽  
Package Design ◽  
Sustainable Product ◽  
Product Package

scholarly journals Linking Sustainability with Geographical Proximity in Food Supply Chains. An Indicator Selection Framework

Agriculture ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 130 ◽  
Author(s):  
Oriana Gava ◽  
Francesca Galli ◽  
Fabio Bartolini ◽  
Gianluca Brunori
Keyword(s):  
Life Cycle ◽  
Supply Chains ◽  
Food Supply ◽  
Social Indicators ◽  
Computer Assisted ◽  
Geographical Proximity ◽  
Food Supply Chains ◽  
Holistic Approaches ◽  
Standard Procedures ◽  
Selection Framework

Despite policymakers’ promotion of food relocalization strategies for burden mitigation, the assumption that local food chains are more sustainable than the global ones might not hold. This literature review tries to highlight a possible framework for exploratory analyses that aim at associating sustainability with the geographical proximity of food supply chains. The purpose of the article is identifying a set of communicative and information-dense indicators for use by evaluators. Bread is the selected test food, given its importance in human nutrition and the relevance of some of its life cycle phases for land use (cereal farming) and trade (cereal commercialization). Article searching (including keyword selection, explicit inclusion/exclusion criteria, and computer-assisted screening using the NVivo® software) was carried out over the Scopus, Web of Science, and Google Scholar databases, and returned 29 documents (refereed and non-refereed publications). The retrieved literature shows varied research focus, methods, and depth of analyses. The review highlighted 39 environmental, 36 economic, and 27 social indicators, along the food chain. Indicators’ reporting chains are heterogeneous; even the comparison of standard procedures, e.g., Life Cycle Assessment, is not straightforward. Holistic approaches are missing.

scholarly journals Are Short Food Supply Chains More Environmentally Sustainable than Long Chains? A Life Cycle Assessment (LCA) of the Eco-Efficiency of Food Chains in Selected EU Countries

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4853
Author(s):  
Edward Majewski ◽  
Anna Komerska ◽  
Jerzy Kwiatkowski ◽  
Agata Malak-Rawlikowska ◽  
Adam Wąs ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Supply Chains ◽  
Environmental Impacts ◽  
Food Supply ◽  
Food Distribution ◽  
Large Variability ◽  
Food Supply Chains ◽  
Short Food Supply Chains ◽  
Efficiency Indicators

Improving the eco-efficiency of food systems is one of the major global challenges faced by the modern world. Short food supply chains (SFSCs) are commonly regarded to be less harmful to the environment, among various reasons, due to their organizational distribution and thus the shortened physical distance between primary producers and final consumers. In this paper, we empirically test this hypothesis, by assessing and comparing the environmental impacts of short and long food supply chains. Based on the Life Cycle Assessment (LCA) approach, we calculate eco-efficiency indicators for nine types of food distribution chains. The analysis is performed on a sample of 428 short and long food supply chains from six European countries. Our results indicate that, on average, long food supply chains may generate less negative environmental impacts than short chains (in terms of fossil fuel energy consumption, pollution, and GHG emissions) per kg of a given product. The values of eco-efficiency indicators display a large variability across analyzed chains, and especially across different types of SFSCs. The analysis shows that the environmental impacts of the food distribution process are not only determined by the geographical distance between producer and consumer, but depend on numerous factors, including the supply chain infrastructure.

scholarly journals Life cycle assessment in the food supply chain: a case study

2015 ◽  
Vol 18 (2) ◽  
pp. 140-154 ◽  
Author(s):  
David McCarthy ◽  
Aristides Matopoulos ◽  
Philip Davies
Keyword(s):  
Life Cycle Assessment ◽  
Supply Chain ◽  
Life Cycle ◽  
Food Supply ◽  
Food Supply Chain

scholarly journals Life Cycle Assessment Across the Food Supply Chain

2012 ◽  
pp. 115-144 ◽  
Author(s):  
Lisbeth Mogensen ◽  
John E. Hermansen ◽  
Niels Halberg ◽  
Randi Dalgaard ◽  
J.C. Vis ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Supply Chain ◽  
Life Cycle ◽  
Food Supply ◽  
Food Supply Chain

scholarly journals Food Waste and Byproduct Valorization through Bio-processing: Opportunities and Challenges

BioResources ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. 5774-5777 ◽  
Author(s):  
Xavier Turon ◽  
Joachim Venus ◽  
Mehrdad Arshadi ◽  
Michalis Koutinas ◽  
Carol S. K. Lin ◽  
...  
Keyword(s):  
Supply Chain ◽  
Life Cycle ◽  
Food Waste ◽  
Renewable Resources ◽  
Food Supply ◽  
Working Group ◽  
Critical Mass ◽  
Waste Streams ◽  
Food Supply Chain ◽  
Cost Action

The bioeconomy era will rely on efficient fractionation of renewable resources via integrated biorefineries. The food supply chain waste, despite its inherent variability, could evolve into an important industrial feedstock on account of its availability, versatility, and sustainability, for the production of bio-based products. Waste streams generated from all stages of the life cycle of food products could be refined into different fractions, which will be either purified to high-value molecules or converted via green chemical and/or biotechnological routes for the production of bio-based products. A working group of the EUBis COST Action TD1203 is taking steps to gather a critical mass of knowledge and expertise to create innovation and technological breakthroughs.

Investigation on the Precocity of Regenerated Seedlings from Micro Tom

2011 ◽  
Vol 365 ◽  
pp. 421-427
Author(s):  
Yan Xu ◽  
Sheng Ta Jin ◽  
Mei Ling Zhao ◽  
Wei Shi ◽  
Qian Sheng Liao ◽  
...  
Keyword(s):  
Life Cycle ◽  
Lycopersicon Esculentum ◽  
Culture Medium ◽  
Scientific Research ◽  
Model Organism ◽  
Ms Medium ◽  
Short Life ◽  
Initial Height ◽  
External Conditions

Micro Tom is a novel breed model organism of Lycopersicon esculentum Mill. It has the a short life cycle and is dwarf and miniature. Owing to these characters, the utilization of Micro Tom can decrease the period of scientific research greatly and save time and space for breeding, so its application is more and more broad. In this paper, we successfully induced the regenerated seedlings from Micro Tom to bear fruits in advance by controlling and optimizing several external conditions such as the initial height of the regenerated seedlings, the culture medium, the photoperiod and the temperatures, etc. Before maturity induction, we firstly investigated the proper methods for plantlets regeneration and got a relative complete data. In the later investigation on precocity inducing we found that the optimum inducing culture medium is MS medium supplemented with 0.1 mg/L NAA and 0.5 mg/L IBA, the proper height of seedlings is 2.0-2.5 cm, the best photoperiod is 18-20h, and the most efficient culturing temperature is 22-26°C. In this way we can get regenerated seedlings from Micro Tom in an efficient way and make them precocity in vitro.

scholarly journals Genetics and Regulation of Chitobiose Utilization inBorrelia burgdorferi

2001 ◽  
Vol 183 (19) ◽  
pp. 5544-5553 ◽  
Author(s):  
Kit Tilly ◽  
Abdallah F. Elias ◽  
Jennifer Errett ◽  
Elizabeth Fischer ◽  
Radha Iyer ◽  
...  
Keyword(s):  
Life Cycle ◽  
Borrelia Burgdorferi ◽  
Bacterial Growth ◽  
Growth Temperature ◽  
Culture Medium ◽  
Significant Proportion ◽  
Ixodid Tick ◽  
Nutrient Acquisition ◽  
Wild Type ◽  
Membrane Spanning

ABSTRACT Borrelia burgdorferi spends a significant proportion of its life cycle within an ixodid tick, which has a cuticle containing chitin, a polymer of N-acetylglucosamine (GlcNAc). TheB. burgdorferi celA, celB, andcelC genes encode products homologous to transporters for cellobiose and chitobiose (the dimer subunit of chitin) in other bacteria, which could be useful for bacterial nutrient acquisition during growth within ticks. We found that chitobiose efficiently substituted for GlcNAc during bacterial growth in culture medium. We inactivated the celB gene, which encodes the putative membrane-spanning component of the transporter, and compared growth of the mutant in various media to that of its isogenic parent. The mutant was no longer able to utilize chitobiose, while neither the mutant nor the wild type can utilize cellobiose. We propose renaming the three genes chbA,chbB, and chbC, since they probably encode a chitobiose transporter. We also found that thechbC gene was regulated in response to growth temperature and during growth in medium lacking GlcNAc.

The Experimental Production of Life Cycles in Ciliates

1930 ◽  
Vol 7 (2) ◽  
pp. 132-142
Author(s):  
HUGH H. DARBY
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Culture Medium ◽  
Life Cycles ◽  
Ion Concentration ◽  
Experimental Production ◽  
Optimum Conditions ◽  
Gradual Decline ◽  
Division Rate

Constant division rate in ciliates can be maintained by keeping the culture medium at constant optimum H-ion concentration. The variations in division rate found in the typical protozoan life history, including gradual decline and death, can be reproduced experimentally by altering the pH of the medium. When cultures are maintained under optimum conditions, encystment and conjugation can take place at any age; the life cycle disappears. An explanation based on experiment is given for the apparently contradictory findings of Maupas. Neither conjugation nor endomixis has any effect on the division rate under constant conditions. The length of the endomictic period is affected by the H-ion concentration of the medium.

Sign in / Sign up

Export Citation Format

Share Document