The influence of cysteine, cysteine analogs, and other amino acids on spore germination of Alternaria species

1991 ◽  
Vol 69 (11) ◽  
pp. 2353-2356 ◽  
Author(s):  
Donald J. Daigle ◽  
Peter J. Cotty
Keyword(s):  
Amino Acids ◽  
Spore Germination ◽  
Leaf Spot ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Potato Dextrose Broth ◽  
Alternaria Leaf Spot ◽  
Cotton Plants ◽  
Alternaria Species

The influence of amino acids on spore germination of Alternaria eassiae was investigated to develop a basis for improvement of mycoherbicide formulations. At a 1% concentration, the majority of amino acids exhibited little or no effect on spore germination in vitro. However, aspartic and glutamic acids stimulated germination, and serine, tryptophan, cysteine, and phenylalanine inhibited spore germination. Cysteine was the strongest inhibitor of germination and was active in the presence of potato dextrose broth, which is normally stimulatory. One percent cysteine reduced germination 96% after 4 h. Derivitization of the mercaptan or amino group but not the carboxylic acid group diminished the ability to inhibit spore germination. Cysteine also inhibited spore germination of Alternaria crassa and Alternaria macrospora. Application of cysteine reduced development of Alternaria leaf spot on cotton plants inoculated with A. macrospora. The results demonstrate diverse effects of amino acids on spore behavior and suggest cysteine or similar compounds may be useful in preventing diseases caused by Alternaria species. Key words: amino acids, biological control, cysteine, germination, potato dextrose broth, Alternaria leaf spot.

scholarly journals Germinant Synergy FacilitatesClostridium difficileSpore Germination under Physiological Conditions

mSphere ◽  
2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Travis J. Kochan ◽  
Michelle S. Shoshiev ◽  
Jessica L. Hastie ◽  
Madeline J. Somers ◽  
Yael M. Plotnick ◽  
...  
Keyword(s):  
Amino Acids ◽  
Clostridium Difficile ◽  
Spore Germination ◽  
Bile Salts ◽  
Gi Tract ◽  
Infectious Diarrhea ◽  
Content Type ◽  
Increased Risk ◽  
Calcium Reabsorption

ABSTRACTClostridium difficileis a Gram-positive obligate anaerobe that forms spores in order to survive for long periods in the unfavorable environment outside a host.C. difficileis the leading cause of nosocomial infectious diarrhea worldwide.C. difficileinfection (CDI) arises after a patient treated with broad-spectrum antibiotics ingests infectious spores. The first step inC. difficilepathogenesis is the metabolic reactivation of dormant spores within the gastrointestinal (GI) tract through a process known as germination. In this work, we aim to elucidate the specific conditions and the location within the GI tract that facilitate this process. Our data suggest thatC. difficilegermination occurs through a two-step biochemical process that is regulated by pH and bile salts, amino acids, and calcium present within the GI tract. Maximal germination occurs at a pH ranging from 6.5 to 8.5 in the terminal small intestine prior to bile salt and calcium reabsorption by the host. Germination can be initiated by lower concentrations of germinants when spores are incubated with a combination of bile salts, calcium, and amino acids, and this synergy is dependent on the availability of calcium. The synergy described here allows germination to proceed in the presence of inhibitory bile salts and at physiological concentrations of germinants, effectively decreasing the concentrations of nutrients required to initiate an essential step of pathogenesis.IMPORTANCEClostridium difficileis an anaerobic spore-forming human pathogen that is the leading cause of nosocomial infectious diarrhea worldwide. Germination of infectious spores is the first step in the development of aC. difficileinfection (CDI) after ingestion and passage through the stomach. This study investigates the specific conditions that facilitateC. difficilespore germination, including the following: location within the gastrointestinal (GI) tract, pH, temperature, and germinant concentration. The germinants that have been identified in culture include combinations of bile salts and amino acids or bile salts and calcium, butin vitro, these function at concentrations that far exceed normal physiological ranges normally found in the mammalian GI tract. In this work, we describe and quantify a previously unreported synergy observed when bile salts, calcium, and amino acids are added together. These germinant cocktails improve germination efficiency by decreasing the required concentrations of germinants to physiologically relevant levels. Combinations of multiple germinant types are also able to overcome the effects of inhibitory bile salts. In addition, we propose that the acidic conditions within the GI tract regulateC. difficilespore germination and could provide a biological explanation for why patients taking proton pump inhibitors are associated with increased risk of developing a CDI.

scholarly journals Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh

2021 ◽  
Author(s):  
Sayma T. Nira ◽  
Md. Farhad Hossain ◽  
Nur Uddin Mahmud ◽  
Oliul Hassan ◽  
Md. Tofazzal Islam ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Maximum Growth ◽  
Pathogenicity Test ◽  
Culture Studies ◽  
Alternaria Leaf Spot ◽  
Cultural Methods ◽  
Molecular Phylogenetic ◽  
Alternaria Sp

  This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.  

Relative host resistance to Alternaria leaf spot in canola and mustard varieties is defined by Alternaria species

2020 ◽  
Vol 71 (7) ◽  
pp. 689
Author(s):  
Hebba F. D. Al-Lami ◽  
Ming Pei You ◽  
Martin J. Barbetti
Keyword(s):  
Host Resistance ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Severe Disease ◽  
Indian Mustard ◽  
Moderate Level ◽  
Alternaria Leaf Spot ◽  
Ethiopian Mustard ◽  
Alternaria Species ◽  
Collapse Index

Both Alternaria japonica and A. brassicae cause severe Alternaria leaf spot on canola (Brassica napus) and mustard (B. juncea). We tested 103 Brassicaceae varieties including 93 Australian canola, nine Indian mustard, and a single variety of Ethiopian mustard (B. carinata) under greenhouse conditions to identify host resistance to Alternaria leaf spot caused by A. japonica and A. brassicae in terms of disease incidence (percentage leaf disease incidence, %LDI), disease severity (percentage leaf area diseased, %LAD) and defoliation (percentage leaf collapse index, %LCI). Against A. japonica, across the three parameters, B. napus Surpass 404 CL was the most resistant (%LDI 7.5, %LAD 5.0, %LCI 0). Varieties Hyola 635 CC, Oscar, AG-Outback and Rottnest, with %LDI 15.6–19.4 and %LAD 12.5–15.6, also showed strong resistance, and with %LCI 10. Varieties 47C02, ATR-Signal and Clancy of B. napus showed a moderate level of resistance across %LDI (21.2–25.6) and %LAD (15.0–20.6), along with a low level of defoliation (%LCI 10). Varieties 46C03, 46C72, ATR-Cobbler and Granite TT of B. napus also showed a moderate level of resistance, with %LDI 23.1–28.7, %LAD 18.1–20.6 and %LCI 11.2–14.4. The significance of this resistance against A. japonica is highlighted by the severe disease on B. napus Thunder TT (%LDI 78.8, %LAD 72.5, %LCI 47.5). Against A. brassicae, all varieties showed susceptibility; however, B. napus ATR-Grace was the least susceptible in relation to disease incidence (%LDI 41.2) and severity (%LAD 36.2), and B. napus Hyola 450 TT the most susceptible (%LDI 90.0, %LAD 82.5). Variety Hurricane of B. napus was the least susceptible in terms of consequent defoliation (%LCI 11.2) and B. napus CBTM Tribune the most susceptible (%LCI 81.2). The B. carinata variety BCA 1 (ATC 95065) and all test B. juncea varieties showed susceptibility to both pathogens. These findings demonstrate high levels of resistance across Australian canola varieties against A. japonica that can be directly deployed where A. japonica is important and can be utilised by breeders for improving resistance in future varieties. By contrast, susceptibility across Australian canola and mustard varieties to A. brassicae is concerning, highlighting a need to locate suitable resistances and, until effective host resistance can be located, to develop and deploy cultural and chemical options.

scholarly journals In vitro evaluation of fungicides against Alternaria leaf spot of cotton

2020 ◽  
Vol 8 (4) ◽  
pp. 3571-3575
Author(s):  
Kaki Pranaya ◽  
Bharati N Bhat ◽  
G Uma Devi ◽  
S Triveni
Keyword(s):  
Leaf Spot ◽  
In Vitro Evaluation ◽  
Alternaria Leaf Spot

scholarly journals Study of antioxidant, anticoagulation and antiaggregational activity in vitro of a number of aliphatic and aromatic amino acid salts

2020 ◽  
Vol 64 (11) ◽  
pp. 77-82
Author(s):  
Natalia A. Bondareva ◽  
◽  
Peotr P. Purygin ◽  
Yury P. Zarubin ◽  
Alexandr V. Samorodov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Hydrocarbon Chain ◽  
Acid Group ◽  
High Reactivity ◽  
Dual Function ◽  
Synthesis Methods ◽  
Amino Acid Salts ◽  
Acid Salts

Among the nitrogen-containing organic substances there are compounds with a dual function. Particularly important are amino acids. Strictly speaking, amino acids make up only one of the many families of organic compounds. Any organic molecule having at least one amino and one acid group may be assigned to this family. This generally means any hydrocarbon chain that may be branched, with or without other functional groups, aromatic rings, or any other organic structure. Therefore, it becomes clear that the number of amino acids that can be imagined is infinite. Today in Russia there is an urgent need to develop new and effective drugs for the treatment of various diseases. This important task involves organizing the production of new competitive domestic medicines on the market, the development of which is carried out on the basis of the results of fundamental scientific research in the field of organic synthesis. In this regard, derivatives and salts of amino acids are of great interest, due to their high reactivity and wide use in medical practice. We have studied the effect on the hemostasis system of derivatives based on amino acid salts, which is currently a key task of organic, bioorganic and medicinal chemistry. Consideration of the scientific literature on this topic showed the saturation and increasing interest in the influence of amino acid compounds throughout the world. The synthesis of amino acid salts and the study of their effect on the blood curability system was carried out, optimal synthesis methods for an organic compound were developed. Preliminary in vitro preclinical studies of the obtained compounds were carried out in order to find out the prospects for their further use.

scholarly journals Alternaria Leaf Spot Caused by Alternaria Species: An Emerging Problem on Ornamental Plants in Italy

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2275-2287
Author(s):  
Slavica Matić ◽  
Giulia Tabone ◽  
Angelo Garibaldi ◽  
Maria Lodovica Gullino
Keyword(s):  
Leaf Spot ◽  
Ornamental Plants ◽  
Infected Plant ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Seed Transmission ◽  
Host Specialization ◽  
Alternaria Leaf Spot ◽  
Fungal Isolates ◽  
Alternaria Species

Serious outbreaks of Alternaria leaf spot and plant decay have recently been recorded on several ornamental plants in the Biella Province (Northern Italy). Twenty-two fungal isolates were obtained from Alternaria infected plant tissues from 13 ornamental hosts. All the isolates were identified morphologically as small-spored Alternaria species. Multilocus sequence typing, carried out by means of ITS, rpb2, tef1, endoPG, Alt a 1, and OPA10-2, assigned 19 isolates as Alternaria alternata, two isolates as belonging to the Alternaria arborescens species complex, and one isolate as an unknown Alternaria sp. Haplotype analyses of ornamental and reference A. alternata isolates from 12 countries identified 14 OPA10-2 and 11 endoPG haplotypes showing a relatively high haplotype diversity. A lack of host specialization or geographic distribution was observed. The host range of the studied A. alternata isolates expanded in cross-pathogenicity assays, and more aggressiveness was frequently observed on the experimental plants than on the host plants from which the fungal isolates were originally isolated. High disease severity, population expansion, intraspecies diversity, and increased range of experimental hosts were seen in the emergence of Alternaria disease on ornamentals. More epidemiological and molecular studies should be performed to better understand these diseases, taking into consideration factors such as seed transmission and ongoing climate changes.

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