Crown Gall on Castor Bean Leaves: II. FORMATION OF SECONDARY TUMOURS

Secondary tumours were formed on the cotyledonary leaf petiole,the hypocotyl, and first true leaf of castor bean seedlingsafter inoculating the blades of the cotyledonary leaves withAgrobacterium tumefaciens. Depending on the strain of bacteriaemployed, 0 to 80 per cent of the plants developed secondarytumours. The ability of different strains to initiate secondarytumours was not obviously correlated with their relative effectivenessin initiating primary tumours. Though all produced primary tumours,five out of ten auxotrophic strains failed to yield secondarytumours, whereas only one out of 14 prototrophic strains failedto do so. Both the number of plants developing secondary tumoursand the frequency with which these tumours occurred on differentparts of the plant were positively correlated with the concentrationof the primary inoculum. Tumours also developed on the cotyledonaryleaf petiole and on the hypocotyl after vacuum infiltrationof A. tumefaciens into the blade of cotyledonary leaves. Inmost instances (9 out of 11 plants) no tumours were formed onthe blade of the infiltrated leaf. Thus, tumour formation equivalentto secondary tumours can occur in the absence of a primary tumouror an overt primary wound. Excision of inoculated leaves showedthat the stimulus for secondary tumour formation moves fromthe blade to the hypocotyl within 24 h. Attempts to demonstratethe presence of a sub-cellular tumour-initiating agent in homogenatesof inoculated leaves were unsuccessful. A. tumefaciens, however,was found in the petiole of the cotyledonary leaf and in thehypocotyl within 24 h of inoculation. The migrating agent responsiblefor secondary tumour formation in castor beans is concludedto be intact bacteria.     

Histology of Callogenesis and Somatic Embryogenesis Induced in Stem Fragments of Cork Oak (Quercus suber) Cultured In Vitro

Calluses able to produce somatic embryos were formed duringin vitro culture of shoot fragments of cork oak (Quercus suberL.).Histological monitoring of these fragments during cultureshowed that it was the cortical parenchyma cells which underwentdedifferentiation before calluses were formed by repeated divisions.The calluses consisted of parenchyma cells surrounded by a fewlayers of meristematic cells. Proembryos formed in groups aroundthe edge of some calluses. Histological examination showed thatthey were produced by the evolution of two different categoriesof cell: one category had the appearance of ‘embryogenic’cells with very thick walls, a small vacuole rich in starchand a well-developed nucleus with a prominent nucleolus. Theother cells were very bulky with large vacuoles; their morphologywas similar to that of suspensor cells encountered in embryogenesisin gymnosperms. The ontogenic stages were similar to those describedin zygotic embryos of the genus Quercus. Nevertheless, mostof the embryonic structures deviated from normal developmentand at all stages produced secondary proembryos. Cork-oak, Quercus suber L, histology, callogenesis, somatic embryogenesis, embryogenic cells, starch, secondary embryogenesis     

Salinity reduction of the end-Triassic sea from the Alpine region into northwestern Europe

A palaeoecological analysis of the Penarth Group (='Rhaetic') of southern England and Wales is undertaken in terms of a species-richness comparison with the Zlambach and Kössen Beds of the Austrian Alps. The three groups studied, bivalves, foraminifers and ostracodes, comprise the most important invertebrate faunas occurring in the deposits cited. All show significant diversity from the Alps into northwest Europe. Coupled with the disappearance of stenohaline elements including ammonites, and taking into account other facies information, the evidence suggests a transgression of a shallow epicontinental sea in northwest Europe at the end of the Triassic. The salinity of this sea (˜25–30%□) was appreciably below that of the Tethyan ocean.     

Recent Developments to Mitigate Selenium Deficiency in Agricultural Eco-Systems

Under changing climate, trace elements like selenium (Se) have emerged as vital constituent of agro-ecosystems enabling crop plants to off-set the adverse effects of suboptimal growth conditions. The available form of selenium is important for boosting its bioavailability to crop plants having varied agro-botanical traits and root architectural systems. As compared to selenite, the selenate has a weaker soil bonding, higher absorption in the soil solution which results in a comparatively absorption by plant roots. Various factors including dry climate, high pH, optimal ambient air temperature, less accumulation of water, and low concentration of organic matter in the soil tend to boost the selenate ratio in the soil. The use of selenium pelleted seeds has emerged as an interesting and viable alternative to alleviate selenium deficiency in agricultural eco-systems. Similarly, the co-inoculation of a mixture of Selenobacteria and Arbuscular mycorrhizal fungi represents an evolving promising strategy for the bio-fortification of wheat plants to produce selenium-rich flour to supplement human dietary needs. Furthermore, in-depth research is required to assure the effectiveness of biological fertilization procedures in field conditions as well as to explore and increase our understanding pertaining to the underlying main mechanisms and channels of selenium absorption in plants. The focus of this review is to synthesize the recent developments on Se dynamics in soil-plant systems and emerging promising strategies to optimize its levels for crop plants. Recent developments regarding the use of micro-organisms as a biotechnological mean to enhance plant nutrition and crop quality have been objectively elaborated. The study becomes even more pertinent for arid and semi-arid agro-ecosystems owing to the potential role of selenium in providing stress tolerance to crop plants. Moreover, this review synthesizes and summarizes the recent developments on climate change and bioavailability, and the protective role of selenium in crop plants.

     

The Primacy of Moringa (<i>Moringa oleifera</i> Lam.) in Boosting Nutrition Status and Immunity Defence Amidst the COVID-19 Catastrophe: A Perspective

A severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led novel coronavirus disease (COVID-19) outbreak spread through China has become the biggest global public health challenge today. The virus upon several mutations has led to the resurgence of more infectious and lethal variants infecting over 298 million people with more than 5.46 million deaths worldwide by the end of December, 2021. Though vaccines are available, various preventive measures particularly a high body immunity is still extremely important which determines the likelihood of disease severity and subsequent recovery in the current and future pandemics. This review acknowledges the potentiality of miraculous Moringa oleifera Lam. against recently evolved novel coronavirus and accompanying health complications. Moringa a well-proven super-food, densely packed with an abundant quantity of 92 minerals, several vitamins, 46 antioxidants, and numerous bioactive compounds, thus own a massive therapeutic potential for healing all levels of nutritional deficiencies and poor immunities and cure above 300 diseases. Moringa acts as anti-asthmatic, anti-cancerous, anti-diabetic, anti-inflammatory, hypotensive, hepatic, renal and cardio-protective, and anti-viral in nature. Thus it may reduce the severity of COVID-19 infections and associated serious medical emergencies. In addition, self-isolation at home or the workplace has put people at increased risk of physical and mental sicknesses, which could be simply addressed by integrating this wonderful plant into everyday diet. Furthermore, the immune-modulatory properties and viral inhibiting nature of moringa contribute to reduced risk of COVID-19 infection and quicker recovery from its symptoms. As per the existing pieces of literature, it is a great time to harness the esteemed moringa for safeguarding people from the terrible ongoing COVID-19 situation and other future pandemics.     

Vibrio cholerae laboratory infection of the adult house fly Musca domestica

The present study was designed to test the hypothesis that house flies may be capable of specifically harbouring ingested Vibrio cholerae in their digestive tracts. Flies were continuously fed green fluorescent protein (GFP)‐labelled, non‐O1/non‐O139 environmental strains of V. cholerae. Bacterial burdens were quantitatively measured using plate counts and localization was directly observed using confocal microscopy. Vibrio cholerae were present in the fly alimentary canal after just 4 h, and reached a plateau of ～10⁷ colony‐forming units (CFU)/fly after 5 days in those flies most tolerant of the pathogen. However, individual flies were resistant to the pathogen: one or more flies were found to carry < 180 V. cholerae CFU at each time‐point examined. In flies carrying V. cholerae, the pathogen was predominantly localized to the midgut rather than the rectal space or crop. The proportion of house flies carrying V. cholerae in the midgut was dose‐dependent: the continuous ingestion of a concentrated, freshly prepared dose of V. cholerae increased the likelihood that fluorescent cells would be observed. However, V. cholerae may be a transient inhabitant of the house fly. This work represents the first demonstration that V. cholerae can inhabit the house fly midgut, and provides a platform for future studies of host, pathogen and environmental mediators of the successful colonization of this disease vector.     

The rapid evaluation of bacterial growth in blood cultures by selected ion flow tube-mass spectrometry (SIFT-MS) and comparison with the BacT/ALERT automated blood culture system

We compared the performance of the BacT/ALERT automated blood culture system with real-time, quantitative volatile organic compound (VOC) detection by selected ion flow tube-mass spectrometry (SIFT-MS). Blood samples from healthy donors were artificially infected with 5 or 100 CFU of organisms commonly causing bacteremia. Positive results by SIFT-MS analysis of headspace gases were recorded for 53/60 (88.3%) bottles at 8h, and 58/60 (96.6%) bottles at 24 h. We conclude that SIFT-MS is a sensitive method for the detection of microbial VOCs. Furthermore, profiles of the VOCs detected may allow simultaneous identification of infecting organisms.