Part II: Impedance-based DNA biosensor for detection of isolated strains of phytopathogen Ralstonia solanacearum.

In Part I, we demonstrated the complete development of a label-free, ultra-low sample volume requiring DNA-based biosensor to detect Ralstonia solanacearum, an aerobic non-spore-forming, Gram-negative, plant pathogenic bacterium, using non-faradaic electrochemical impedance spectroscopy (nf-EIS). We also presented the sensor's sensitivity, specificity, and electrochemical stability. In this article, we highlight the specificity study of the developed DNA-based impedimetric biosensor to detect various strains of R. solanacearum. We have collected seven isolates of R. solanacearum isolated from locally infected host plants (eggplant, potato, tomato, chilli, and ginger) from different parts of Goa, India. The pathogenicity of these isolates was tested on the eggplant, and the pathogen was confirmed by microbiological plating and polymerase chain reaction (PCR). We further report the insight into the DNA hybridization on the surface of Interdigitated Electrodes (IDEs) and the expansion of the Randles model for more accurate analysis. The interpretation of the sensor specificity is clearly demonstrated by the capacitance change observed at the electrode-electrolyte interface.

Part I: Non-faradaic electrochemical impedance-based DNA biosensor for detecting phytopathogen - Ralstonia solanacearum.

Herein, we report for the first time the development of a label-free, non-faradaic, and highly sensitive DNA-based impedimetric sensor using micro-sized gold interdigitated electrodes (IDE) to detect a soil-borne agricultural pathogen Ralstonia solanacearum. A universal 30 oligomer single-stranded DNA (ssDNA) probe lpxC4 having specificity towards R. solanacearum is successfully immobilized on the surface of IDE along with mercaptohexanol. The electrochemical stability of the developed sensor surface is determined using open circuit potential measurements. The DNA probe immobilization protocol is validated using the changes configured on the surface of IDE by contact angle and ATR-FTIR analysis. The DNA target hybridization is detected using non-faradaic electrochemical impedance spectroscopy measurement with an ultra-low sample volume of 10 µL. The non-faradaic approach is verified by studying redox behavior using cyclic voltammetry. We investigate the hybridization of the surface-immobilized label-free probe with the complementary DNA targets obtained from infected eggplant saplings and cross-reactive studies with mismatched DNA strands. Our impedimetric sensor can detect target concentrations as low as 0.1 ng/µL. This standardization and detection of DNA hybridization serves as part I of the work and paves the way for further study in the detection of pathogenic field samples.

Plant pathogenicity and associated/related detection systems. A review.

There is an increasing demand for the development of various tools for diagnosis and control of plant infections. The early diagnosis of plant disease serves as a vital element to improve crop productivity and meet demands of the ever-growing world population. The traditional methods of plant disease detection are time consuming, laborious and require 3-5 days to estimate the disease incidence. In this review, we focus on the advances in the detection techniques, mainly the miniaturized systems that has developed in the last decade. The analytical techniques for plant pathogen detection have been classified as direct and indirect detection methods. The direct methods involving laboratory techniques such as polymerase chain reaction, enzyme-linked immune-sorbent assays, and immunofluorescence and their recent advances have been discussed. Similarly, indirect methods which rely on sensing the plant stress indicators to detect plant diseases have been categorized and reviewed. In the last decade, various detection platforms with high sensitivity and selectivity have been developed and commercialized into handheld devices and products for on-field plant disease detection. This review focusses on the transition from the gold standard techniques to the advanced on-field biosensors to detect plant diseases with higher accuracy, cost-effective and making timely diagnosis possible. A growing trend for pathogen detection based on biosensors has been highlighted and further categorized into electrochemical, optical, and mass-based sensors. These innovative advancements in plant pathogen detection systems help to make the agricultural sector more safe, reliable, and sustainable for the ever-growing population.

A review of recent advances in plant-pathogen detection systems.

Worldwide, a substantial economic loss in agricultural products is caused by plant pathogens. The increased losses in agriculture have drawn attention towards the development of miniaturized pathogen detection systems for phytopathology. This review paper's main selling point supports recent research (from 2015 to 2022) and technological advancements in the field of plant pathogen detection. The article discusses in depth important developments in the loop-mediated isothermal amplification (LAMP) assay, microfluidics, Molecular Imprinted Polymer (MIP) based biosensors, digital droplet PCR (ddPCR), disposable all-printed electronics, and nanoparticle-based sensors for instantaneous pathogen detection in agricultural applications. Utilizing nanoparticles to identify agricultural pathogens is a crucial topic that is explored. A brief on various commercially available detection systems worldwide have been listed. Finally, we discuss the perspective in the development of portable miniaturized systems and novel assay technologies based on advanced nanomaterials. Gold standard techniques: Although Polymerase Chain Reaction (PCR) and culture counting have been widely used for plant pathogen detection, they are not appropriate for measurements made in the field due to their higher installation costs, lack of portability, need for well-equipped laboratories, and requirement of skilled personnel. Therefore, these recent trends are overtaking the traditional methods in Agri-diagnostics because of their superior performances and suitability for the task.

Toxic and Teratogenic Effects of Prenatal Alcohol Exposure on Fetal Development, Adolescence, and Adulthood.

Prenatal alcohol exposure (PAE) can have immediate and long-lasting toxic and teratogenic effects on an individual's development and health. As a toxicant, alcohol can lead to a variety of physical and neurological anomalies in the fetus that can lead to behavioral and other impairments which may last a lifetime. Recent studies have focused on identifying mechanisms that mediate the immediate teratogenic effects of alcohol on fetal development and mechanisms that facilitate the persistent toxic effects of alcohol on health and predisposition to disease later in life. This review focuses on the contribution of epigenetic modifications and intercellular transporters like extracellular vesicles to the toxicity of PAE and to immediate and long-term consequences on an individual's health and risk of disease.

Raman spectroscopy reveals age- and sex-related differences in cortical bone from people with osteoarthritis.

Bone strength in human cortical bone is determined by the composition and structure of both the mineral and collagen matrices and influenced by factors such as age, gender, health, lifestyle and genetic factors. Age-related changes in the bone matrix are known to result in loss of mechanical strength and increased fragility. In this study we show how Raman spectroscopy, with its exquisite sensitivity to the molecular structure of bone, reveals new insights into age- and sex-related differences. Raman analysis of 18 samples of cortical hip bone obtained from people aged between 47-82 years with osteoarthritis (OA) found subtle changes in the lipid and collagen secondary structure, and the carbonate (CO32-) and phosphate (PO43-) mineral ratios in the bone matrix. Significant differences were observed between older and younger bones, and between older female and older male bones; no significant differences were observed between younger male and female bones. Older female bones presented the lowest mineral to matrix ratios (MMR) and highest CO32-/PO43- ratios, and relative to lipid/collagen -CH2 deformation modes at 1450 cm-1 they had lowest overall mineral content, higher collagen cross linking and lipid content but lower levels of α-helix collagen structures than older male and younger male and female bones. These observations provided further insight on bone composition changes observed in the bone volume fraction (BV/TV) for the older female bones from microCT measurements on the same samples, while tissue mineral density (TMD) measurements had shown no significant differences between the samples.

A case of infiltrative cecal endometriosis with appendiceal obliteration and lymph node involvement.

Endometriosis is a clinical condition with a wide spectrum of severity, and a subset that includes intestinal involvement that may even mimic malignancy, making non-surgical diagnosis difficult. Cecal endometriosis is a rare finding among intestinal endometriosis. We report on 33-year-old woman with ileocecal endometriosis presenting as endoscopic prolapse of the ileocecal valve associated with a mass on cross-sectional imaging. The diagnosis was suggested intraoperatively by peritoneal endometrioma and obliteration of the appendix during laparoscopic right hemicolectomy. Pathological review demonstrated extensive submucosal, infiltrative endometriosis with mass effect and lymph node involvement. This case highlights the difficulty in preoperative diagnosis of intestinal endometriosis and the wide-ranging potential tissue effects in cases of infiltrative disease.

A case of colonic intussusception and obstruction secondary to giant colonic lipoma.

Lipomas are benign soft tissue tumors found throughout the body including the gastrointestinal (GI) tract. Colonic lipomas are typically asymptomatic, incidentally identified during endoscopy or at the time of autopsy. However, giant lipomas larger than 4 cm usually manifest symptoms such as abdominal pain, obstruction, melena or intussusception. The transverse colon is the least common location for colonic lipoma. We report on a 54-year-old man with acute large bowel obstruction secondary to a long segment colo-colonic intussusception from a giant lipoma originating in the transverse colon. The diagnosis was suggested by advanced imaging and confirmed on endoscopy. He was treated successfully by laparoscopic extended right hemicolectomy with ileocolonic anastomosis. This case highlights the complexity of presentation and surgical management of large bowel obstruction and colonic intussusception, as well as the rare entity of giant colonic lipoma.