Phospholipid N -methyltransferases produce various methylated phosphatidylethanolamine derivatives in thermophilic bacteria

One of the most common pathways for the biosynthesis of the phospholipid phosphatidylcholine (PC) in bacteria is the successive three-fold N -methylation of phosphatidylethanolamine (PE) catalyzed by phospholipid N -methyltransferases (Pmts). Pmts with different activities have been described in a number of mesophilic bacteria. In the present study, we identified and characterized the substrate and product spectrum of four Pmts from thermophilic bacteria. Three of these enzymes were purified in an active form. The Pmts from Melghirimyces thermohalophilus , Thermochromogena staphylospora and Thermobifida fusca produce monomethyl-PE (MMPE) and dimethyl-PE (DMPE). T. fusca encodes two Pmt candidates, one is mutationally inactivated and the other is responsible for the accumulation of large amounts of MMPE. The Pmt enzyme from Rubellimicrobium thermophilum catalyzes all three methylation reactions to synthesize PC. Moreover, we show that PE, previously reported to be absent in R. thermophilum , is in fact produced and serves as precursor for the methylation pathway. In an alternative route, the strain is able to produce PC by the PC synthase pathway when choline is available. The activity of all purified thermophilic Pmt enzymes was stimulated by anionic lipids suggesting membrane recruitment of these cytoplasmic proteins via electrostatic interactions. Our study provides novel insights into the functional characteristics of phospholipid N -methyltransferases in a previously unexplored set of thermophilic environmental bacteria. Importance In recent years, the presence of phosphatidylcholine (PC) in bacterial membranes has gained increasing attention, partly due to its critical role in the interaction with eukaryotic hosts. PC biosynthesis via a three-step methylation of phosphatidylethanolamine, catalyzed by phospholipid N -methyltransferases (Pmts), has been described in a range of mesophilic bacteria. Here, we expand our knowledge on bacterial PC formation by the identification, purification and characterization of Pmts from phylogenetically diverse thermophilic bacteria, and thereby provide insights into the functional characteristics of Pmt enzymes in thermophilic actinomycetes and proteobacteria.

Diseases connected with work in hay in Iceland. Causes and scientific studies

Diseases connected with work in hay have been known in Iceland for a long time. In 1981 scientific studies of these diseases were started in Iceland at the request of the Farmers Union. The results of these studies are summarized in this article. In studies of hay a great amount of storage mites, moulds and thermophilic actinomycetes (microlyspora faeni) were found in addition to allergens from mice and pollen. Symptoms caused by hay dust were mainly from nose and eyes in people with positive skin tests, but cough, dyspnea and fever were equally common in those with negative skin tests. The most common causes of allergy in farming families were storage mites and cattle, but allergy to cats, dogs and grass pollen were less common rurally than in the Reykjavik area. When comparing individuals working in heavy hay dust with those working in cleaner air, the former group had a higher likelihood of having a positive precipitin test against micropolyspora faeni, fever after work in hay and airway obstruction. It was shown that Icelandic farmers were more likely to get emphysema than other people irrespective of smoking. In a large study of homes in the Reykjavik area almost no mites were found. In spite of this, positive specific IgE tests against dust mites were equally common as in Uppsala, Sweden, where dust mites were found in 16% of homes. In further studies it was found, that 57% of people in the study had been more and less exposed to hay dust. They had either been raised on a farm, been on a farm in the summer during childhood or owned horses and fed them with hay. We have argued that cross allergy to storage mites may be the cause of a rather common allergy to house dust mites. A new study of middle-aged individuals has shown that allergy to storage mites is a little more common in the Reykjavik area than in Aarhus, Bergen or Uppsala. The most likely explanation is that they have more often been exposed to hay dust.

Biological characteristics and classification of thermophilic actinomycetes showed extracellular hydrolytic enzymes producing ability isolated from compost

Compost is a highly humified organic fertilizer, rich in nutrients and a source of a variety of aerobic microorganisms, including actinomycetes, which develop in response to different levels of temperature, humidity, oxygen and pH. Microbes growing on the compost are believed to have the ability to produce extracellular hydrolytic enzymes. The purpose of this study was to determine the ability of thermophilic actinomycetes XM21 isolated from compost in producing hydrolytic enzymes, namely cellulase, amylase, protease, and lipase. The confirmation tests of hydrolytic enzymes-producing ability were conducted by inoculating the microbes into media containing cellulose, starch, gelatin and tween 80, using the method of disc diffusion. The results showed that strain XM21 capable of extracellular enzymes producing, such as cellulase, protease, amylase, lipase. Strain XM21 can grow well with high cellulase activity in a wide range of temperature between 30-55oC, optimum at 45oC. The strain can grow well on different media, utilized carbon sources with pH 5-10, and salinity of 0-5%. On the agar plate, the strain has white aerial mycelia, the mature spore chains appeared spirals, moderately long, bearing 10 to 35 spores each. Based on the biological characteristics and phylogenetic analysis of 16S rDNA, it can be concluded that strain XM21 is close to Streptomyces flavovariabilis (98, 12%), hence identified as Streptomyces flavovariabilis XM21.

Properties of Thermobifida fusca peroxidase Tfu-1649 and its combined synergistic effects with xylanase on lignocellulose degradation

Lignocelluloses are comprised of cellulose, hemicellulose, and lignins, which constitute plant biomass. Since peroxidases can degrade lignins, the authors examined peroxidase Tfu-1649, which is secreted from the thermophilic actinomycetes, Thermobifida fusca BCRC 19214. After cultivating for 48 h, the culture broth accumulated 43.66 U/mL of peroxidase activity. The treatment of four types of lignocellulolytic byproducts, i.e., bagasse, corncob, pin sawdust, and Zizania latifolia Turcz husk, with Tfu-1649 alone increased the total phenolic compounds, with limited reducing sugars, but treatment with xylanase, Tfu-11, and peroxidase Tfu-1649 showed synergistic effects. Hence, the co-operative degradation of lignocelluloses by both peroxidase and xylanase could contribute to biomass decomposition and further applications in the agricultural and environmental industries.

Occurrence and Analysis of Thermophilic Poly(butylene adipate-co-terephthalate)-Degrading Microorganisms in Temperate Zone Soils

The ubiquity and character of thermophilic poly(butylene adipate-co-terephthalate) (PBAT)-degrading microorganisms in soils were investigated and compared to the process in an industrial composting plant. PBAT degraders were sought in 41 temperate zone soils. No mesophilic degraders were found by the employed method, but roughly 102 colony-forming units (CFUs) of thermophilic degraders per gram of soil were found in nine soils, and after an enrichment procedure, the PBAT-degrading consortia were isolated from 30 out of 41 soils. Thermophilic actinomycetes, Thermobispora bispora in particular, together with bacilli proved to be the key constituents of the isolated and characterized PBAT-degrading consortia, with bacilli comprising from about 30% to over 90% of the retrieved sequences. It was also shown that only consortia containing both constituents were able to decompose PBAT. For comparison, a PBAT film together with two types of PBAT/starch films were subjected to biodegradation in compost and the degrading microorganisms were analyzed. Bacilli and actinobacteria were again the most common species identified on pure PBAT film, especially at the beginning of biodegradation. Later, the composition of the consortia on all three tested materials became very similar and more diverse. Since waste containing PBAT-based materials is often intended to end up in composting plants, this study increases our confidence that thermophilic PBAT degraders are rather broadly present in the environment and the degradation of the material during the composting process should not be limited by the absence of specific microorganisms.

Hypersensitivity pneumonitis

Hypersensitivity pneumonitis is an immune-mediated lung disease in which the repeated inhalation of certain antigens provokes a hypersensitivity response, with granulomatous inflammation in the distal bronchioles and alveoli of susceptible people. A diverse range of antigens including bacteria (Thermophilic actinomycetes), fungi (Trichosporon cutaneum), animal proteins (bird antigens), mycobacteria, and chemicals may cause the disease. The commonest forms are bird fancier’s lung, farmer’s lung, humidifier lung, and metal-working fluid pneumonitis. In some cases no antigen is identified. Acute disease is characterized by recurrent episodes of breathlessness, cough, fevers, malaise, and flu-like symptoms occurring 4–8 hours after antigen exposure. Fever and basal crackles are the main physical signs. Chronic disease is characterized by the insidious development of dyspnoea and persistent pneumonitis, sometimes progressing to lung fibrosis. Clinical features are similar to those of other varieties of pulmonary fibrosis, but clubbing is uncommon.

Occupational immunologic lung disease

Occupational immunologic lung disease is characterized by an immunologic response in the lung to an airborne agent inhaled in the work environment and can be subdivided into immunologically mediated occupational asthma (OA) and hypersensitivity pneumonitis (HP). Irritant-induced OA, a separate nonimmunologic entity, can be due to chronic exposure to inhaled irritants or reactive airways dysfunction syndrome (RADS). RADS is defined as an asthma-like syndrome that persists for >3 months and occurs within minutes to hours after a single exposure to a high concentration of a respiratory irritant. Workers in high-risk fields for OA include farmers, printers, wood workers, painters, plastics workers, cleaners, spray painters, electrical workers, and health-care workers. OA can be triggered by high-molecular-weight (HMW) proteins that act as complete allergens or by low-molecular-weight (LMW) sensitizers that act as haptens. HMW proteins (>10 kDa) are generally derived from microorganisms (such as molds and bacteria, including thermophilic actinomycetes), plants (such as latex antigens and flour proteins), or animals (such as animal dander, avian proteins, and insect scales) and are not specifically regulated by the Occupational Safety and Health Administration. LMW haptens that bind to proteins in the respiratory mucosa include some Occupational Safety and Health Administration regulated substances, such as isocyanates, anhydrides, and platinum. HP can present in an acute, chronic, or subacute form. The acute, subacute, and early chronic form is characterized by a CD4+ T-helper type 1 and CD8+ lymphocyte alveolitis. Classically, the bronchoalveolar lavage in HP will show a CD4/CD8 ratio of <1.

Extrinsic allergic alveolitis-causing actinomycetes in indoor and farm environments

Suspended airborne particles, of biological origin, can constitute bioaerosols1,2 and they can be of different origin ranging from farm environments dealing with hay, sugar cane, tobacco, mushroom and cotton to refuse disposal sites to military equipment test chambers. These bioaerosols might carry allergenic and pathogenic agents like viruses, spore forming bacteria and fungi, excreta of insects and mites, moss and fern spores, algal and plant cells; enzymes, antibiotics, endotoxins, mycotoxins and fungal glucans1. Although infections from pathogenic viruses, bacteria and fungi may occur in these work environments the commonly reported symptoms relate to allergic rhinitis and asthma, allergic alveolitis (granulomatons pneumonitis) or organic dust toxic syndrome (inhalation fever or toxic pneumonitis)1,2. This article will only provide an overview on the non-infectious lung diseases resulting from long-term exposure to the spores of thermoactinomycetes of the order Bacillales and thermophilic actinomycetes of the order Actinomycetales in indoor and farm environments.