Postinfection Changes Research Articles

Dynamics of reactive oxygen species and lignin biosynthesis during leaf spot disease of Withania somnifera (L.) Dunal.

Withania somnifera is an important medicinal plant, however, its cultivation and quality are compromised through infestation by leaf spot disease caused by the fungus, Alternaria alternata. To find suitable strategies against this disease, studies on post-infectional changes are important. ROS are critical as they interact with other defence signalling pathways. We analyzed ROS-generating and scavenging systems in healthy and diseased leaf samples of W. somnifera and ROS-driven downstream defence pathways. We used DAB and NBT assays for ROS detection, spectrophotometry and in-gel assays for ROS scavenging enzymes, a thioglycolic acid (TGA) based assay, histochemical staining for lignin, and qRT-PCR for transcript-level expression. Leaf spot infection in W. somnifera increased NADPH oxidase activity and ROS accumulation in infected leaves, together with enhanced antioxidant enzyme activity. Leaf spot-infected leaves had increased lignin content and higher expression of lignin biosynthesis genes. In addition, transcript levels of defence-related genes, NPR1 and PR, were also upregulated. The present work provides insights into responses to leaf spot disease through defence-related signalling in W. somnifera. It demonstrates crosstalk between ROS and lignin biosynthesis. This work identified potential targets for developing strategies to confer disease resistance against A. alternata in W. somnifera.

Online Identification of Obsessive-Compulsive Symptoms and Relevant Factors in Patients with Covid-19 in Turkey During Quarantine

Abstract. Aim: Via online interviews, this study identifies the obsessive-compulsive symptoms (OCSs) of patients diagnosed with Covid-19 and quarantined at home for 14 days, to determine the incidence of these symptoms, to detect OCSs in the early period, and to identify the associated risk factors. Method: This research was designed as a descriptive and cross-sectional study. The study population consisted of patients who had tested positive in the real-time PCR test for Covid-19 and were quarantined at home in the Şanlıurfa Province of Turkey. The study sample comprised 800 patients contacted between January and April 2021. The data were collected online using a questionnaire that included sociodemographic characteristics, questions on postinfection changes, and the Padua Inventory, a valid tool for determining the level of OCSs. Results: The frequency of obsessive-compulsive symptoms during quarantine was calculated as 11.2%, and the mean Padua Inventory score was 48.19 ± 19.17. Conclusion: The results of this study show that patients quarantined at home for 14 days with the diagnosis of Covid-19 are less likely to exhibit obsessive-compulsive symptoms during this period. It also shows that the risk of OCSs was lower particularly in patients who had completed a university or higher education and had no previous psychiatric disease or chronic disease diagnosis.

Post-infectional changes associated with the progression of leaf spot disease in Calotropis procera Aiton

The present work was designed to study the post-infectional alterations associated with the disease progression during leaf spot disease caused by Passalora calotropidis in Calotropis procera. It is an important medicinal plant of family Apocynaceae and subfamily Asclepiadaceae. In the present work, various parameters such as leaf area, number of leaf spots, biochemical parameters, i.e., total chlorophyll content, total protein content, and antioxidative enzyme activities, i.e., catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) were studied to assess the post-infectional changes associated with the disease progression. Various organic acids, i.e., malic acid (MA), succinic acid (SA), citric acid (CA) and fumaric acid (FA) were also analyzed by using GC-MS. It was found that total chlorophyll and total protein contents decreased in disease severity level 1 (DS1), DS2, DS3, DS4 and DS5 significantly as compared to the healthy plant (DS0). The results of antioxidant enzymes indicate that the activities of CAT, APX and GPX were increased in disease progressed leaves as compared to the healthy plant leaves. Similarly trend was found for CA. The present study suggested a complicated basis of post infectional changes, the facts obtained is helpful for better interpretation of host pathogen interaction.

Transcriptional analysis and histochemistry reveal a dominant role for cell wall signaling in mediating Pythium myriotylum resistance in Zingiber zerumbet

Although post infection changes in cell wall constituents are known to induce the immune response in plants against necrotrophs, little is known about the role of the cell wall in mediating resistance in Zingiber zerumbet (L.) Smith (Zingiberaceae) against the soil-borne necrotrophic oomycete Pythium myriotylum Drechsler, which causes soft-rot disease. Using RNA-Seq in combination with custom gene expression microarray we studied the temporal expression profile of 46 wall-associated genes in Z. zerumbet against P. myriotylum inoculation. Many genes that promote cell wall loosening were suppressed. Similarly, the genes involved in the biosynthesis and the signaling of phytohormones and the receptor-like kinases that mediate cell elongation were also suppressed. Several monolignol biosynthetic pathway genes were up-regulated. Histochemistry of the collar region of the aerial stem revealed H2O2 accumulation, increased lignification of the mesophyll cells surrounding vascular bundles in the leaf sheath and the significant increase in total lignin content. Pathogen hyphae were restricted to peripheral leaf sheath and were not extended into the pith through which the principal portion of the connective tissues passes in the aerial stem. Results highlight a coordinated transcriptional reprogramming of cell wall-associated genes to bring about changes in cell wall composition to minimize the cell wall damage caused by pathogen factors and to render the cell wall less amenable to pathogen penetration. The study illustrates a key role for cell wall fortification in preventing pathogen colonization in the vascular tissues, thus ensuring the transport system remains unaffected by the pathogen invasion.

Post-Infectional Biochemical Changes in <i>Cymbopogon martinii</i> (Roxb.) Wats and <i>Cymbopogon citratus</i> (DC) Stapf. Due to Leaf Rust Disease

Post-infectional changes in sugars, ascorbic acid, protein, phenols, chlorophyll and carotene of two Cymbopogons viz., Cymbopogon martinii and Cymbopogon citratus due to leaf rust caused by Puccinia nakanishikii (Diet) were investigated. All the biochemical constituents decreased in plants infected by the fungal pathogen.

Use of Pyrosequencing and Denaturing Gradient Gel Electrophoresis to Examine the Effects of Probiotics and Essential Oil Blends on Digestive Microflora in Broilers Under MixedEimeriaInfection

A protective digestive microflora helps prevent and reduce broiler infection and colonization by enteropathogens. In the current experiment, broilers fed diets supplemented with probiotics and essential oil (EO) blends were infected with a standard mixed Eimeria spp. to determine effects of performance enhancers on ileal and cecal microbial communities (MCs). Eight treatment groups included four controls (uninfected-unmedicated [UU], unmedicated-infected, the antibiotic BMD plus the ionophore Coban as positive control, and the ionophore as negative control), and four treatments (probiotics BC-30 and Calsporin; and EO, Crina Poultry Plus, and Crina PoultryAF). Day-old broilers were raised to 14 days in floor pens on used litter and then were moved to Petersime batteries and inoculated at 15 days with mixed Eimeria spp. Ileal and cecal samples were collected at 14 days and 7 days postinfection. Digesta DNA was subjected to pyrosequencing for sequencing of individual cecal bacteria and denaturing gradient gel electrophoresis (DGGE) for determination of changes in ileal and cecal MC according to percentage similarity coefficient (%SC). Pyrosequencing is very sensitive detecting shifts in individual bacterial sequences, whereas DGGE is able to detect gross shifts in entire MC. These combined techniques offer versatility toward identifying feed additive and mild Eimeria infection modulation of broiler MC. Pyrosequencing detected 147 bacterial species sequences. Additionally, pyrosequencing revealed the presence of relatively low levels of the potential human enteropathogens Campylobacter sp. and four Shigella spp. as well as the potential poultry pathogen Clostridiun perfringens. Pre- and postinfection changes in ileal (56%SC) and cecal (78.5%SC) DGGE profiles resulted from the coccidia infection and with increased broiler age. Probiotics and EO changed MC from those seen in UU ilea and ceca. Results potentially reflect the performance enhancement above expectations in comparison to broilers not given the probiotics or the specific EO blends as feed supplements.

Expression ofBacillus cereushemolysin II inBacillus subtilisrenders the bacteria pathogenic for the crustaceanDaphnia magna

Hemolysin II (HlyII) is a pore-forming toxin of the opportunistic pathogen Bacillus cereus. Despite our understanding of the mechanism of HlyII cytotoxicity in vitro, many of its characteristics, including potential target cells, conditions of its action and expression, are not known. Here we report that the expression of hlyII in Bacillus subtilis renders the bacteria hemolytic and is able to kill the crustacean Daphnia magna. The hemolytic activity of hlyII-encoded B. subtilis strains in culture media is positively correlated with virulence in D. magna. Fluorescence microscopy reveals postinfection changes in the mitochondrial potential of intestinal tissue, suggesting that the formation of ionic pores leads to cell death. In the presence of the transcriptional regulator HlyIIR, HlyII expression decreases 200-fold, and B. subtilis expressing both hlyII and hlyIIR remains hemolytic, but not pathogenic to the crustacean.

Post-infectional biochemical changes in mulberry leaves affected by <i>Cercospora moricola</i> Cook and its effect on cocoon characters of the silkworm, <i>Bombyx mori</i> L.

Key words: Mulberry; biochemical changes; cocoon characters; leaf spot disease; Cercospora moricola Univ. j. zool. Rajshahi Univ. Vol.21, 2002. pp. 85-87

Etude hématologique séquentielle d’une infection expérimentale induite par le virus de la maladie de Gumboro chez des poulets, des dindes et des canards

Des poulets de chair, des dindonneaux et des cannetons âgés de quatre semaines ont été infectés expérimentalement avec le virus de la maladie de Gumboro, puis des échantillons sanguins ont été prélevés chronologiquement pour analyser les changements sanguins après l’infection. Bien qu’il y ait eu une nette augmentation des valeurs de l’hématocrite chez les poulets, atteignant un pic de 31 p. 00, 12 à 144 h postinfection, il y a eu, au contraire, une baisse générale de ces valeurs chez les dindonneaux et les cannetons avec des valeurs minimales respectivement de 26,5 p. 100 à 12 h postinfection et de 28,2 p. 100 à 48 h postinfection. La numération leucocytaire a augmenté chez les poulets de manière significative (p < 0,05) pour atteindre un pic de 66,83 x 103/μl à 120 h postinfection, alors que chez les dindonneaux, elle a diminué jusqu’à 26,75 x 103/μl à 96 h postinfection. Chez les poulets, une première diminution s’est produite entre trois et six heures après infection, pour atteindre la valeur la plus basse de 5,9 x 103/μl à 48 h postinfection. Une baisse semblable a été enregistrée chez les dindonneaux avec comme valeur minimale 7,81 x 103/μl à 48 h postinfection. Les nombres d’hétérophiles ont évolué chez les trois espèces d’une manière semblable à celle observée pour la numération leucocytaire. Alors que la numération des éosinophiles a d’abord augmenté chez les poulets pour atteindre un pic de 1,93 x 103/μl à 6 h postinfection, puis a diminué, ces valeurs ont d’abord diminué chez les dindonneaux, jusqu’à un minimum de 0,88 x 103/μl à 6 h postinfection, puis ont augmenté, atteignant un maximum de 5,7 x 103/μl à 72 h postinfection. Toutes les valeurs hématologiques sont cependant restées relativement inchangées chez les cannetons. Les résultats ont montré que les poulets étaient affectés de lymphocytopénie en deux phases, d’éosinophilie et d’hétérophilie, les dindonneaux de lymphocytopénie et d’éosinophilie retardée, et que les cannetons avaient été peu affectés. Ceci renforce le fait qu’il existe des niveaux de sensibilité différents chez ces trois espèces de volaille.

Post-infectional changes in the phospholipids of the leaves of a cotton plant variety resistant toVerticillium dahliae

The class and fatty acid compositions of the phospholipids (PLs) of young leaves of healthy, cotton plants of the wilt-resistant variety 175-F and of plants of the same variety infected with the pathogenic fungusVerticillium dahliae Kleb. have been determined. The positional distributions of the fatty acids in the main classes of PLs have been established, and their possible molecular compositions have been calculated. The changes in the composition of the PLs taking place under the influence of infection have been elucidated.

Ultrastructural studies on the post‐infection changes inIxora coccineainfected byalternaria alternata

The present study reports the post infection changes caused by Altemaria alternata (Fr) Keisler infection in Ixora coccinea L. var. bandhuca Roxb. The hyphae are intercellular and branched. The hyphal cytoplasm contains mitochondria, with narrow cristae, circular nucleus and ribosomes. Host cytoplasm contains hexagonal crystalline inclusions, mitochondria with sparse cristae and large ellipsoid lipid inclusions in the early infection stages. Mature stages of infection showed disorganization of entire cytoplasm leading to the agglutination of the organelles.

Changes in nutritional value of guava fruits infected by major post-harvest pathogens.

Post-infection changes in ascorbic acid, sugars, proteins and phenols were studied in guava fruits infected by major post-harvest pathogens which in order of importance were Colletotrichum gloeosporioides, (Penz.), Botryodiplodia theobromae, Pat., Rhizopus arrhizus Fischer., Phomopsis psidii Nag Raj and Ponnappa apud Ponnappa and Nag Raj, and Pestalotiopsis versicolor (Speg.) Steyaert. Contents of ascorbic acid, sugars and proteins declined in the fruits infected by Botryodiplodia theobromae, Colletotrichum gloeosporioides, Pestalotiopsis versicolor, Phomopsis psidii and Rhizopus arrhizus. Total phenols increased in fruits infected by Pestalotiopsis versicolor and Rhizopus arrhizus while reverse was observed in fruits infected by other pathogens.

Post-infection changes in lipids of the roots of a cotton plant variety moderately resistant to Verticillium dahliae

A comparative study has been made of the lipid composition of healthy roots of the cotton plant of the Tashkent-1 variety (I) and of the corresponding plants infected withVerticillium dahliae Kleb. (II) grown under field conditions. The action of the factors of infection stress and seasonal and climatic conditions change the lipid metabolism. In lipids (I) and (II) seven classes of neutral lipids (NLs), three classes of glycolipids, and six classes of phospholipids (PLs) were identified and their fatty acid compositions were determined. It was established that in (II) there was a smaller amount of total lipids, NLs, and PLs, and an increased level of polyphenolic pigments, but the level of gossypol pigments with free aldehyde groups was unchanged. In the NLs of (II), as compared with (I), there were more triacylglycerols, sterols, triterpenols, and squalene. Complex changes were observed in the fatty acid composition of the acyl-containing lipids.

Postinfectional changes of lipids and photosynthesis in Lycopersicon esculentum susceptible to Phytophthora capsici

In Lycopersicon esculentum susceptible to Phytophthora capsici we have observed that the lipids of the host and of the parasite displayed different fatty acid compositions: some specific to the plant (16:1 trans, 16:3 and 18:3α), others to the parasite (18:3γ, 20:3, 20:4 and 20:5). In three distinguishable foliar zones: (i) under explant (highly infected tissues), (ii) infected and (iii) apparently non-infected tissues of tomato leaflet, some fatty acids varied such as a function of the distance of the infection point: for example 18:3α decreased by 91% in infected foliar zone, when C20, (totally lacking in healthy tomato leaflets), increased gradually from non-infected to under explant foliar zones. These lipid changes could be used as an infection index. The decrease of 18:3α, fatty acid specific of the galactolipids, was correlated to the disappearance of photosynthetic activities in infected tissues in which chlorophyll contents stayed remarkably stable. These chlorophylls never pheophytinized, were unfunctional for the gathering of light energy for PS II. The in vitro culture of the parasite, in the presence of leaflet extract did not indicate any metabolization of the 18:3α. We finally propose a scheme of the possible effects of the parasitism, on the fatty acid metabolism at the cellular level.

A rat model for bacterial otitis media.

Rat middle ear was exposed to challenge with viable pneumococci, type 3 and 6A, and the course of changes in the middle ear was observed by otomicroscopy and analysis of bacterial samples from blood, nasopharynx and middle ear effusions. Microscopical examination of changes in the middle ear mucosa during and after the acute infection was also made. Depending on the type and concentration of pneumococci, three different results were observed: otitis media with purulent effusion, otitis media with serous effusion, or no reaction at all. The mortality rate was low and most animals recovered within 10 days without postinfectional changes visible by otomicroscopy. The microscopical examination of the middle ear mucosa revealed distinct changes. Inoculation of rat middle ear with pneumococci causes a self-limiting infection that closely resembles acute otitis media in the human. Thus the rat would seem to be a suitable animal model for the study of bacterial otitis media.

Postinfectional Changes of Lipid Metabolism in Potato Tuber Resistant and Susceptible to Phytophthora infestans

AbstractThe effect of Phytophthora infestans on the lipid content and composition as well as lipid acyl hydrolase activity in the potato tuber of two cultivars, Nysa – horizontal resistant and Bintje –susceptible were investigated.In the susceptible cultivar the infection resulted in: a qualitative changes in aminolipids, an increase in steroid content, an inconsiderable decrease in amount of glycolipids and a slight drop in FFA, no significant changes in composition of total, FA and slight loss in acyl hydrolase activity.The following changes were observed in the resistant cultivar: a considerable enhancement of steroid content (reached in about 400 %), a slight increase in amount of glycolipid, a rapid drop of acyl hydrolase activity and FFA content and a considerable increase in oleic acid level in total FA.In the response to both infection and aging in both cultivars no significant quantitative changes in lipid‐phosphorus and sulfolipids were noted.

Seasonal Changes in Molecular Forms of Acid Phosphatase and Ribonuclease of Potato Tubers and the Effects of Infection by Phytophthora erythroseptica

Sequential changes in total activity and molecular forms of acid phosphatase and ribonuclease from potato tubers were studied by seasonal assays and Sephadex gel filtration. Ribonuclease and p -nitrophenyl phosphatase activity fluctuated during storage of tubers, while β-glycerophosphatase declined to a low level coincident with initiation of sprout growth. In recently-lifted tubers acid phosphatase activity occurred in a single high molecular weight peak. Two new forms of lower molecular weight appeared during ageing of stored tubers. The influence of infection by a tuber-rotting fungus, Phytophthoraerythroseptica , on these seasonal changes was variable. No consistent effects on total hydrolase activities were observed, while post-infectional changes in molecular forms included a pronounced shift in the major acid phosphatase peak. The possible significance of this molecular weight change in infected samples is discussed in the light of recent evidence concerning the sub-unit structure of acid phosphatase from potato tubers.

Postinfection Changes in Chemical Compounds of Lemons Caused by Phytophthora citrophthora

Postinfection Changes in Chemical Compounds of Lemons Caused by Phytophthora citrophthora

Post-infection changes in sugar and organic acid contents of chilli (Capsicum annuum L.) and mango (Mangifera indica L.) leaves

Die Infektion der Blatter vonCapsicum annuum undMangifera indica mit den BlattpilzenCurvularia ovoidea beziehungsweiselunata hat zur Folge, dass die freien Zucker Saccharose, Glukose und Fruktose verschwinden und dass der Gehalt an organischen Sauren (Apfelsaure, Zitronensaure, Oxalsaure) vermindert wird.

Cellular responses in lungs of immunized mice to intranasal infection with Coccidioides immitis.

The role of cells in immunity to pulmonary infection with Coccidioides immitis was studied in mice vaccinated with formalin-killed spherules and endospores and infected intranasally with arthrospores. Postinfection changes in lung and body wt., lung histology, and numbers of inflammatory cells obtained by tracheobronchial washing commenced more rapidly in vaccinated mice than in nonvaccinated controls. However, once begun, the changes were greater in the latter animals. In tracheobronchial washings made 12 hr. after infection, the percentage of alveolar macrophages with intracellular arthrospores was the same in both groups of animals. But after 24 hr. a much smaller percentage of macrophages had intracellular spherules in the washings from vaccinated mice than in those from controls. It is postulated that macrophages of vaccinated mice ingest arthrospores in vivo at the same rate as macrophages of control animals, but are better able to prevent the intracellular spores from developing into spherules.