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At least 109 records · Page 6Linked to original sources
PubMed2000

A genetic analysis of crystal growth.

The regulation of crystal morphology by proteins is often observed in biology. It is a central feature in the formation of hard tissues such as bones, teeth and mollusc shells. We have developed a genetic system in the bacterium Escherichia coli to study the protein-mediated control of crystal growth. We have used the crystallization of gold as a model system and found polypeptides that control the morphology of the resulting gold crystals. Analysis of the crystallization process influenced by these polypeptides indicates they act catalytically by an acid mechanism. Our results suggest that the concepts and methods of microbial genetics are general and can be applied to substances not commonly found in biological systems.

Acids↗
PubMed1969

Cold-sensitive mutations in Salmonella typhimurium which affect ribosome synthesis.

A number of mutations (45) expressed as cold-sensitive conditional lethal pheno-types were screened by transduction for their linkage to the streptomycin-resistance locus; 7 showed such linkage. Of these, two were studied in greater detail. The sedimentation profiles of ribosomes from cultures grown at low temperature differed from wild type and from one another. Both mutants lost ribonucleic acid control at low temperature. It is suggested that a high proportion of mutants expressing a cold-sensitive phenotype harbor mutations in genes affecting ribosome synthesis or regulation.

Bacterial Proteins↗
PubMed2005

Molecular techniques in the diagnosis and management of infectious diseases: do they have a role in bacteriology?

The diagnosis and management of bacterial diseases has been done by traditional methods for a century or more. With the advent of molecular methods, however, these traditional approaches are being challenged. This review examines the pros and cons of traditional versus modern methods and tries to answer the question: when are molecular methods useful or essential? The following topics are addressed with appropriate examples: diagnosis; identification, typing and fingerprinting; pathogenesis; patient management; susceptibility to disease, and resistance to antimicrobial agents. It was concluded that there is still a place for both traditional and modern molecular methods, and training of staff must include both methodologies. Innovation is encouraged--but new technologies must be thoroughly tested before introduction into the routine lab. Liaison between laboratory scientist and physician is important, but above all experience is paramount.

Bacteriology↗
PubMed2003

Microbial quantification in activated sludge: the hits and misses.

Since the implementation of the activated sludge process for treating wastewater, there has been a reliance on chemical and physical parameters to monitor the system. However, in biological nutrient removal (BNR) processes, the microorganisms responsible for some of the transformations should be used to monitor the processes with the overall goal to achieve better treatment performance. The development of in situ identification and rapid quantification techniques for key microorganisms involved in BNR are required to achieve this goal. This study explored the quantification of Nitrospira, a key organism in the oxidation of nitrite to nitrate in BNR. Two molecular genetic microbial quantification techniques were evaluated: real-time polymerase chain reaction (PCR) and fluorescence in situ hybridisation (FISH) followed by digital image analysis. A correlation between the Nitrospira quantitative data and the nitrate production rate, determined in batch tests, was attempted. The disadvantages and advantages of both methods will be discussed.

Bioreactors↗
PubMed1994

Atopic dermatitis: recent trends in pathogenesis and therapy.

Emerging concepts in the areas related to the pathogenesis and treatment of atopic dermatitis are reviewed. In particular, recent findings have revealed several key steps in the maintenance of a vicious circle of spongiotic dermatitis associated with elevated T-lymphocyte activation, hyperstimulatory Langerhans cells, defective cell-mediated immunity, and B-cell IgE overproduction. The discovery of specific IgE-binding structures on Langerhans cells provides a mechanism for Langerhans cells to capture and present IgE-targeted allergens to allergen-specific T cells. Furthermore, certain microbial allergens that tend to preferentially elicit IgE-type responses also elicit a T-cell response dominated by the IgE-inducing lymphokine interleukin 4. Repeated stimulation by activated Langerhans cells appears to induce just such a response. Abnormal biochemical responsiveness and mediator release by AD monocytes, mast cells, and eosinophils also participate in the sustainment or initiation of such a vicious circle, and contribute directly to the dermatitis as well. Developments in the areas of neuropeptides, genetics, microbial superantigens, and cytokine networks in the skin also appear to have promise in providing a rational link between immune defects and the inflammatory events in AD. Conventional therapy remains the mainstay of atopic dermatitis management; however, new therapies based upon the above concepts are being tested in clinical trials. Although the difficulty of objectively grading AD lesional activity and the high placebo response of AD patients hampers the interpretation of many reports, several types of approaches are coming into focus. The effectiveness of cyclosporin A, which targets T-cell activation and antigen presentation, indicates that additional agents with such activity should be effective, and verifies the criticality of these cells in AD pathogenesis. Therapy with biologic response modifiers, such as interferon gamma or thymopentin, is oriented toward normalization of imbalanced immune responsiveness, rather than direct suppression of the immune system. The mechanism of action of and toxicities of Chinese herbal mixtures require further investigation, but may reveal hitherto unconsidered avenues. Other recent therapeutic trials have focused on reduction of trigger factors, such as house dust mite exposure, foods, and the abnormal epidermal lipid barrier to irritation.

Dermatitis, Atopic↗
PubMed2026

Harnessing probiotics to combat nonylphenol toxicity: a multiomics approach of gut microbiome remodelling in Silurus meridionalis.

BACKGROUND: As a ubiquitous environmental endocrine disruptor, nonylphenol (NP) threatens aquatic organisms, driving the need for sustainable mitigation strategies. While probiotics represent promising eco-friendly supplements, their molecular mechanisms against NP toxicity remain unclear. In this study, S. meridionalis received 7-week of probiotic (Bacillus subtilis and Lactobacillus acidophilus) pretreatment followed by 15 days of NP exposure. Integrated metagenomics, transcriptomics, and metabolomics analyses, with Reverse transcription quantitative real-time PCR (RT‒qPCR) and Enzyme-linked immunosorbent assay (ELISA) validation, were performed to elucidate microbial, genetic and metabolic responses. Growth performance, including the specific growth rate (SGR) and weight gain rate (WGR), was concurrently assessed. RESULTS: NP exposure significantly suppressed WGR and SGR, and induced gut microbiota dysbiosis alongside and lipid metabolism disorders in S. meridionalis. Probiotic pretreatment effectively reversed these toxic effects and restored the inhibited WGR and SGR. Multiomics integration revealed that the protective effects of probiotics were mediated by a coherent "microbe-host" co-metabolism network across 3 progressive layers: (1) Microbial Remodelling: in which beneficial taxa (e.g., Bacteroides eggerthii and Cetobacterium sp.) were enriched, and the functional capacity for short-chain fatty acid (SCFA) synthesis and ethanolamine metabolism was enhanced; (2) Host Gene Regulation: in which key lipid metabolism genes (ek1, cept1, ept1, mogat2, and abcg2a) were upregulated, and lipase activity was restored; and (3) Metabolic Pathway Activation and Physiological Repair: in which the activity of the NP-suppressed Kennedy pathway was reactivated, thereby promoting phosphatidylethanolamine (PE) and phosphatidylcholine (PC) synthesis and ultimately restoring gut barrier function. These results were further were corroborated by RT‒qPCR and ELISA. CONCLUSION: This study systematically elucidated that probiotics alleviated NP toxicity by remodelling a "microbiota-host Kennedy pathway gene-metabolite (PE and PC)-growth performance" regulatory network. The key mechanism is the beneficial microbiota activating the host Kennedy pathway and restoring gut phospholipid homeostasis and barrier function. These findings provide a theoretical basis for developing targeted, lipid metabolism focused probiotic feed additives for use in sustainable aquaculture.

Probiotics↗
PubMed2000

Development of biotechnology in India.

India has embarked upon a very ambitious program in biotechnology with a view to harnessing its available human and unlimited biodiversity resources. It has mainly been a government sponsored effort with very little private industry participation in investment. The Department of Biotechnology (DBT) established under the Ministry of Science and Technology in 1986 was the major instrument of action to bring together most talents, material resources, and budgetary provisions. It began sponsoring research in molecular biology, agricultural and medical sciences, plant and animal tissue culture, biofertilizers and biopesticides, environment, human genetics, microbial technology, and bioprocess engineering, etc. The establishment of a number of world class bioscience research institutes and provision of large research grants to some existing universities helped in developing specialized centres of biotechnology. Besides DBT, the Department of Science & Technology (DST), also under the Ministry of S&T, sponsors research at universities working in the basic areas of life sciences. Ministry of Education's most pioneering effort was instrumental in the creation of Biochemical Engineering Research Centre at IIT Delhi with substantial assistance from the Swiss Federal Institute of Technology, Zurich, Switzerland to make available state-of-the-art infrastructure for education, training, and research in biochemical engineering and biotechnology in 1974. This initiative catalysed biotechnology training and research at many institutions a few years later. With a brief introduction, the major thrust areas of biotechnology development in India have been reviewed in this India Paper which include education and training, agricultural biotechnology, biofertilizers and biopesticides, tissue culture for tree and woody species, medicinal and aromatic plants, biodiversity conservation and environment, vaccine development, animal, aquaculture, seri and food biotechnology, microbial technology, industrial biotechnology, biochemical engineering and associated activities such as creation of biotechnology information system and national repositories. Current status of intellectual property rights has also been discussed. Contribution to the India's advances in biotechnology by the industry, excepting a limited few, has been far below expectations. The review concludes with some cautious notes.

Agriculture↗