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Abstract: Jasmine (Jasminum sambac L.) is an ornamental crop grown in South and Southeast Asia for its flowers for garlands, tea and essential oil production. However, certain fungal foliar and floral diseases significantly reduce its yield. In this study, Colletotrichum sp.-like (cylindrical conidia) and Fusarium sp.- like (lunate conidia) isolates causing leaf spot disease were characterized based on the ingression process and fungal germination in planta. Four-day single-spore cultures in PDA of isolating C1 (Colletotrichum sp.-like) and F2 (Fusarium sp.-like) were obtained. Suspensions of 108 conidia mL-1 were made and sprayed onto young leaves of jasmine. Specimen collection was done at 2, 6, 12, 24, 36, 48, 60 and 72 h after inoculation (hai). Formalin-acetic acid was used to clear the tissues and fungal structures are selectively stained using lactophenol-acid fuschin. Average ingression sites (IS) were counted for each time point under 50X magnification, then IS per leaf area (cm2) was calculated. Fungal isolates remain at the surface of the leaf until 36 h. IS of C1 and F2 almost doubled at 48 hai. However, ingression sites declined at 72 hai for both pathogens, which either imply a progression of sub surface colonization or unsuccessful penetration. Leaf yellowing and a few spots were observed at 48 hai for F2 and at 60 hai for C1. More severe necrotic leaf spots with yellow halo (severity rating of 5) were seen in plants inoculated with Fusarium sp.-like isolated than in those inoculated with Colletotrichum sp.-like isolated. Lastly, at 48 to 60 hai, it was evident that the pathogen started to seek for stomata, which seemed to be the preferred penetration site for both fungal pathogens.
Published in DiRROS: 25.07.2024; Views: 312; Downloads: 159
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Abstract: Purpose To identify the protein profiles in vitreous associated with retinal fibrosis, angiogenesis, and neurite formation in epiretinal fibrovascular membranes (FVMs) in patients with proliferative diabetic retinopathy (PDR). Methods Vitreous samples of 5 non-diabetic control patients with vitreous debris and 7 patients with PDR membranes were screened for 507 preselected proteins using the semi-quantitative RayBio® L-series 507 antibody array. From this array, 60 proteins were selected for a custom quantitative antibody array (Raybiotech, Human Quantibody® array), analyzing 7 control patients, 8 PDR patients with FVMs, and 5 PDR patients without FVMs. Additionally, mRNA levels of proteins of interest were measured in 10 PDR membranes and 11 idiopathic membranes and in retinal tissues and cells to identify possible sources of protein production. Results Of the 507 proteins screened, 21 were found to be significantly elevated in PDR patients, including neurogenic and angiogenic factors such as neuregulin 1 (NRG1), nerve growth factor receptor (NGFR), placental growth factor (PlGF) and platelet derived growth factor (PDGF). Angiopoietin-2 (Ang2) concentrations were strongly correlated to the degree of fibrosis and the presence of FVMs in patients with PDR. Protein correlation analysis showed PDGF to be extensively co-regulated with other proteins, including thrombospondin-1 and Ang2. mRNA levels of glial-derived and brain/derived neurotrophic factor (GDNF and BDNF) were elevated in PDR membranes. These results were validated in a second study of 52 vitreous samples of 32 PDR patients and 20 control patients. Conclusions This exploratory study reveals protein networks that potentially contribute to neurite outgrowth, angiogenesis and fibrosis in the formation of fibrovascular membranes in PDR. We identified a possible role of Ang2 in fibrosis and the formation of FVMs, and of the neurotrophic factors NRG1, PDGF and GDNF in neurite growth that occurs in all FVMs in PDR.
Published in DiRROS: 25.07.2024; Views: 313; Downloads: 267
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Abstract: Recent advances in high-throughput sequencing technologies and bioinformatics have generated huge new opportunities for discovering and diagnosing plant viruses and viroids. Plant virology has undoubtedly benefited from these new methodologies, but at the same time, faces now substantial bottlenecks, namely the biological characterization of the newly discovered viruses and the analysis of their impact at the biosecurity, commercial, regulatory, and scientific levels. This paper proposes a scaled and progressive scientific framework for efficient biological characterization and risk assessment when a previously known or a new plant virus is detected by next generation sequencing (NGS) technologies. Four case studies are also presented to illustrate the need for such a framework, and to discuss the scenarios.
Keywords: NGS, pest risk analysis, virus diseases, biological characterization, plant health, regulatory agencies
Published in DiRROS: 25.07.2024; Views: 339; Downloads: 184
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Abstract: In animal contests, communicating aggressive motivation is most often mediated by visual or acoustic signals, while chemical signals are not expected to serve such a function since they are less able to be modulated by the sender during the changing behavioral context. We describe a rare example of ephemeral olfactory signals in terrestrial animals, signals that are emitted via protrusive scent glands in male cave crickets Troglophilus neglectus (Orthoptera, Rhaphidophoridae) to reflect the state of the signaler’s aggression. We correlate the intensity of behaviorally expressed aggression of the individuals in dyadic contests with the frequency and extent of their gland tissue protrusion, the latter serving as an indication of the amount of released odor. We detected large amounts of odor release during brief gland protrusions, and the absence of its release during gland retraction. Males protruded the glands during and after encountering a rival, with the degree of protrusion increasing with the intensity of the signalers’ aggression. During the encounters, the degree of gland protrusion increased most strongly with the occurrence of the elevated body posture, directly preceding the attack. This degree was significantly higher in encounter winners than in losers displaying such posture, suggesting the highly important role of the released odor for contest resolution. After the encounters, glands were protruded almost exclusively by winners, apparently announcing victory. We tested for the function of the olfactory signals also directly, by preventing gland tissue protrusion in symmetric and asymmetric treatments of the contestants. Treating only the dominant individuals decreased the percentage of encounters they won by over 60%, while treating both contestants elicited a significant increase in the frequency and duration of fights. During contests, the olfactory signals of T. neglectus apparently function as a highly effective threat, which prevents maximal contest escalation and decreases the conflict-related costs.
Keywords: animal behaviour, bioacoustics, aggression
Published in DiRROS: 25.07.2024; Views: 341; Downloads: 219
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Abstract: Next generation sequencing (NGS) technologies are becoming routinely employed in different fields of virus research. Different sequencing platforms and sample preparation approaches, in the laboratories worldwide, contributed to a revolution in detection and discovery of plant viruses and viroids. In this work, we are presenting the comparison of two RNA sequence inputs (small RNAs vs. ribosomal RNA depleted total RNA) for the detection of plant viruses by Illumina sequencing. This comparison includes several viruses, which differ in genome organization and viroids from both known families. The results demonstrate the ability for detection and identification of a wide array of known plant viruses/viroids in the tested samples by both approaches. In general, yield of viral sequences was dependent on viral genome organization and the amount of viral reads in the data. A putative novel Cytorhabdovirus, discovered in this study, was only detected by analysing the data generated from ribosomal RNA depleted total RNA and not from the small RNA dataset, due to the low number of short reads in the latter. On the other hand, for the viruses/viroids under study, the results showed higher yields of viral sequences in small RNA pool for viroids and viruses with no RNA replicative intermediates (single stranded DNA viruses).
Keywords: next generation sequencing, small RNA, ribosomal RNA depleted total RNA, detection, plant viruses, plant viroids
Published in DiRROS: 25.07.2024; Views: 349; Downloads: 210
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