Investigation on the role of plant defensin proteins in regulating plant-Verticillium longisporum interactions in Arabidopsis thaliana

The hemibiotrophic pathogen Verticillium longisporum infects rapeseed (Brassica napus) and poses a real threat to its cultivation. Conventional approaches are limited and are based primarily on the availability of a wide gene pool to identify suitable genotypes for breeding in order to improve resistance, e.g. against abiotic stress or pathogens. In order to achieve this goal also in crop plants with a very narrow gene pool like rapeseed, new strategies have to be developed. One solution could be the expression of plant defensins (PDFs), which are known for their anti-fungal effects. In our laboratory, compatibility factors (CF) were identified in Arabidopsis, the loss of which led to a highly increased expression of AtPDF2.2. There are already numerous examples of how overexpression of such PDFs in model and crop plants led to improved and lasting resistance. This thesis work demonstrated the antifungal role of two AtPDF genes that contribute to the regulation of the Arabidopsis-Verticillium interaction. GUS expression under the AtPDF2.2 promoter showed that AtPDF2.2 was suppressed in Arabidopsis roots 6 days after infection (dpi) and later in leaves (9 dpi). This was confirmed by a transcript analysis that showed strong suppression of the AtPDF2.2 expression and two other Arabidopsis genes of PDF class II. Transgenic lines for AtPDF2.2 overexpression (OE-PDF2.2) and for knockdown (KD-pdf2.2) also showed an increased expression of AtPDF2.3 and AtPDF2.5 in the OE-PDF2.2 line, while a corresponding suppression in the KD-pdf2.2 line was recorded. Another important observation in the KD-pdf2.2 line was an enhanced jasmonic acid (JA) response, accompanied by upregulation of ethylene (ET) and salicylic acid (SA) -dependent genes, an effect that also in other infections with hemibiotrophic pathogens was observed. Therefore, based on available data, it can be assumed that V. longisporum uses host compatibility factors during the early phase of infection to suppress AtPDF2.2 to bypass plant defense. This also suppresses the expression of the closely related genes AtPDF2.3 and 2.5, which enables the fungus to establish a successful infection process. However, the suppression of these three PDFs, in turn, triggers the JA response which subsequently activates ET and SA signaling to mediate the reprogramming of defense response. To investigate the antifungal effect of AtPDF2.2, the OE-PDF2.2 line was analyzed, which showed increased resistance to two fungal (V. longisporum and Sclerotinia sclerotiorum) and one bacterial pathogen (Pseudomonas syringae). In contrast, the KD-pdf2.2 line showed a higher susceptibility to these fungal and bacterial pathogens. However, Verticillium longisporum induces the expression of AtPDF1.2a at 6 dpi in Arabidopsis wild type Col-0. Transcript study in the AtPDF1.2a overexpression (OE-PDF1.2a) and knockout (KO-pdf1.2a) plants revealed that AtPDF1.2a expression positively correlates with Class-I and III AtPDF genes, but negatively to AtPDF2.2, 2.3 and 2.5. Moreover, OE-PDF1.2a plants did not upregulate the expression of JA, ET or SA marker genes but KO-pdf1.2a plants showed induced expression of all the three pathways responsive genes. Possibly, low expression of AtPDF1.2a in KO-pdf1.2a plants during ongoing infection works as a concentration-specific signal. Since OE-PDF1.2a plants did not show significant changes in the expression of upstream JA, ET, and SA responsive genes it might rather be that upon V. longisporum attack AtPDF1.2a positively co-regulates several AtPDF genes from Class-I and III, while suppressing the expression of AtPDF2.2, 2.3 and 2.5 to reprogram the plant defense response. The antifungal activity has already been demonstrated for AtPDF1.2a, but its exact role in plant defense is still unclear. Therefore, OE-PDF1.2a lines were used, AtPDF1.2a seems to have an antifungal effect only on fungal pathogens; V. longisporum and Sclerotinia sclerotiorum but not on the bacterial pathogen

Structural Insights Into Key Plasmodium Proteases as Therapeutic Drug Targets

Malaria, caused by protozoan of genus Plasmodium, remains one of the highest mortality infectious diseases. Malaria parasites have a complex life cycle, easily adapt to their host’s immune system and have evolved with an arsenal of unique proteases which play crucial roles in proliferation and survival within the host cells. Owing to the existing knowledge of enzymatic mechanisms, 3D structures and active sites of proteases, they have been proven to be opportune for target based drug development. Here, we discuss in depth the crucial roles of essential proteases in Plasmodium life cycle and particularly focus on highlighting the atypical “structural signatures” of key parasite proteases which have been exploited for drug development. These features, on one hand aid parasites pathogenicity while on the other hand could be effective in designing targeted and very specific inhibitors for counteracting them. We conclude that Plasmodium proteases are suitable as multistage targets for designing novel drugs with new modes of action to combat malaria

Dynamics of nucleic acid mobility

Advances in sequencing technologies and bioinformatic analyses are accelerating the quantity and quality of data from all domains of life. This rich resource has the potential to reveal a number of important incidences with respect to possible exchange of nucleic acids. Ancient events have impacted species evolution and adaptation to new ecological niches. However, we still lack a full picture of processes ongoing within and between somatic cells, gametes, and different organisms. We propose that events linked to acceptance of alien nucleic acids grossly could be divided into 2 main routes in plants: one, when plants are exposed to extreme challenges and, the second level, a more everyday or season-related stress incited by biotic or abiotic factors. Here, many events seem to comprise somatic cells. Are the transport and acceptance processes of alien sequences random or are there specific regulatory systems not yet fully understood? Following entrance into a new cell, a number of intracellular processes leading to chromosomal integration and function are required. Modification of nucleic acids and possibly exchange of sequences within a cell may also occur. Such fine-tune events are most likely very common. There are multiple questions that we will discuss concerning different types of vesicles and their roles in nucleic acid transport and possible intracellular sequence exchange between species

Calcium-dependent permeabilization of erythrocytes by a perforin-like protein during egress of malaria parasites.

Clinical malaria is associated with proliferation of blood-stage parasites. During the blood stage, Plasmodium parasites invade host red blood cells, multiply, egress and reinvade uninfected red blood cells to continue the life cycle. Here we demonstrate that calcium-dependent permeabilization of host red blood cells is critical for egress of Plasmodium falciparum merozoites. Although perforin-like proteins have been predicted to mediate membrane perforation during egress, the expression, activity and mechanism of action of these proteins have not been demonstrated. Here, we show that two perforin-like proteins, perforin-like protein 1 and perforin-like protein 2, are expressed in the blood stage. Perforin-like protein 1 localizes to the red blood cell membrane and parasitophorous vacuolar membrane in mature schizonts following its Ca(2+)-dependent discharge from micronemes. Furthermore, perforin-like protein 1 shows Ca(2+)-dependent permeabilization and membranolytic activities suggesting that it may be one of the effector proteins that mediate Ca(2+)-dependent membrane perforation during egress

Modification of the communication strategies for the construction of household toilets

Environmental Sanitation Program was a five year project funded by Aga Khan Foundation (AKF) under the assistance with CIDA & EU. This was implemented by Muniwar - Abad Charitable Trust in more than 105 villages in the district of Mehsana, Patan, Banaskantha & Junagadh districts of Gujarat, through their field offices at Sidhpur & Keshod. We would like to share some of our learning from the Sidhpur area

A comparative clinical evaluation of efficacy of Kati Basti with Prabhanjanam Taila and Moorchita Tila Taila in Gridhrasi w.s.r to Sciatica

Kati Basti included under various external procedures of Ayurveda, having variety of actions like the Bahya Snehana (external oleation), Swedana Chikitsa (fomentation therapy). Kati Basti is indicated in various disorders of spine and back like backache, lumbar spondylosis, sciatica, degenerative disc changes etc. Low back pain is most common complaint with a prevalence of 65 to 90%. Improper sitting postures, traveling, use of two wheeler and sports activities are few important causes of backache. Sciatica often used to describe low back pain that spreads (radiates) through the hip, to the back of the thigh, and down the inside of the leg which closely resembles with Gridhrasi. In Sharanghadhara Samhita use of Prabhanjana Taila in Ghridhrasi Vyadhi has been indicated, hence an attempt was made to compare clinically the efficacy of Kati Basti with Prabhanjanam Taila and Moorchita Tila Taila in Gridhrasi with special reference to sciatica

DETECTION OF PLANT LEAF DISEASES IN AGRICULTURE USING RECENT IMAGE PROCESSING TECHNIQUES – A REVIEW

Purpose: Agricultural productivity is something on which the economy highly depends in India as well in all over the world. India is an agriculture-dependent country; wherein about 70% of the population depends on agriculture. Methodology: This is one of the main reasons that disease detection in agriculture plays an important role, as having the disease in plant leaf is quite natural. If proper observations are not taken in the agriculture field then it causes serious effects on plants due to which respective product quality and productivity are affected. Detection of plant leaf disease through effective and accurate automatic technique is beneficial at the starting stage as it reduces a large work of monitoring in big farms of crops. Result: This paper presents the review on the state of the art disease classification techniques presently used using image processing that can be used for plant leaf disease detection in agriculture

SOYBEAN LEAF DISEASES DETECTION AND CLASSIFICATION USING RECENT IMAGE PROCESSING TECHNIQUES

Purpose: India is an agricultural country and soybean production is one of the major sources of earning. Due to the major factors like diseases, pest attacks, and sudden changes in the weather condition, the productivity of the soybean crop decreases. Automatic detection of soybean plant diseases is essential to detect the symptoms of soybean diseases as early as they appear on the growing stage. This paper proposed a methodology for the analysis and detection of soybean plant leaf diseases using recent digital image processing techniques. In this paper, experimental results demonstrate that the proposed method can successfully detect and classify the major soybean diseases. Methodology: MatLab 18a is used for the simulation for the result and machine learning-based recent image processing techniques for the detection of the soybean leaf disease. Main Findings: The main finding of this work is to create the soybean leaf database which includes healthy and unhealthy leaves and achieved 96 percent accuracy in this work using the proposed methodology. Applications of this study: To detect soybean plant leaf diseases in the early stage in Agricultural. The novelty of this study: Self-prepared database of healthy and unhealthy images of soybean leaf with the proposed algorithm

Calcineurin and actin dynamics in calcium-mediated microneme exocytosis

Plasmodium falciparum invades host erythrocytes by multiple invasion pathways. The invasion of erythrocytes by P. falciparum merozoites is a complex process that requires multiple interactions between host receptors and parasite ligands. A number of parasite proteins that mediate interaction with host receptors during invasion are localized to membrane-bound apical organelles referred to as micronemes and rhoptries. The timely release of these proteins to the merozoite surface is crucial for receptor engagement and invasion. It has been demonstrated previously that exposure of merozoites to a low potassium (K(+)) ionic environment as found in blood plasma leads to a rise in cytosolic calcium (Ca(2+)), which triggers microneme secretion. The signalling pathways that regulate microneme discharge in response to rise in cytosolic Ca(2+) are not completely understood. Here, we show that a P. falciparum Ca(2+)-dependent protein phosphatase, calcineurin (PfCN), is an essential regulator of Ca(2+)-dependent microneme exocytosis. An increase in PfCN activity was observed in merozoites following exposure to a low K(+) environment. Treatment of merozoites with calcineurin inhibitors such as FK506 and cyclosporin A prior to transfer to a low K(+) environment resulted in inhibition of secretion of microneme protein apical merozoite antigen-1 (PfAMA-1). Inhibition of PfCN was shown to result in reduced dephosphorylation and depolymerization of apical actin, which appears to be criticalfor microneme secretion. PfCN thus serves as an effector of Ca(2+)-dependent microneme exocytosis by regulating depolymerization of apical actin. Inhibitors that target PfCN block microneme exocytosis and limit growth of P. falciparum blood-stage parasites providing a novel approach towards development of new therapeutic strategies against malaria

Evaluation of antioxidant and anti-ulcerative potential of Citrullus lanatus seed extract in rats

In the present study antioxidant and antiulcer potential of Citrullus lanatus seeds were evaluated. Antioxidant activity of all the extracts (chloroform, ethylacetate and methanol) was measured by DPPH method. Methanolic extract of Citrullus lanatus (MECL) seeds showed maximum antioxidant potential and was evaluated for its anti-ulcerogenic activity by pyloric ligated (PL) and water immersion stress (WIS) induced ulcer models in rat. Gastric volume and free and total acidity were measured in PL model whereas; ulcerative index was measured in both the models at 100, 200 and 300 mg/kg doses of MECL. Rats treated with MECL (300 mg/kg) showed significant decrease in the gastric volume, free acidity and total acidity in case of PL model and showed significant percentage inhibition of ulcer as indicated by decrease in ulcerative index in both the models. The extract of Citrullus lanatus seeds possesses good antioxidant and anti-ulcer activity.Colegio de Farmacéuticos de la Provincia de Buenos Aire