Population dynamics of the potato tuber moth on processing tomatoes in Israel

The potato tuber moth (PTM),Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a major pest of processing tomatoes,Lycopersicon esculentum Mill. (Solanaceae), in Israel. The larvae penetrate the tomato fruit through the stem end and present a serious threat to crop quality. Foliage and fruit samples were taken in nine commercial tomato fields located in Israel's three main tomato growing areas, two of which are potato growing areas as well. PTM was not found where potatoes were absent. Potato harvest in nearby fields was found to be the most significant factor affecting seasonal trends in PTM population density in tomatoes. All four larval instars were found in foliage on all sampling dates. Significantly higher proportions of first instars were found during the population density increase which followed potato harvest. Damaged fruits did not contain first instar larvae, indicating that PTM never undergoes complete development within tomato fruit. Fruit damage levels at harvest were positively correlated to the peak mean population densities on foliage and the date they were observed. In tomato fields not adjacent to potatoes, infestation was first observed at the edge of the field. Both before and after the potato harvest in nearby fields, population density at the edge of the field was significantly higher than at the center. In tomato fields adjacent to potatoes, no significant differences were found between population densities at the edge and center before the potatoes were harvested. After the potato harvest, population density at the center of tomato fields was higher than at the edge. Deceased, October 1988     

miR-192 Directly Binds and Regulates Dicer1 Expression in Neuroblastoma

Neuroblastoma (NB) arises from the embryonic neural crest and is the most common extracranial solid tumor in children under 5 years of age. Reduced expression of Dicer1 has recently been shown to be in correlation with poor prognosis in NB patients. This study aimed to investigate the mechanisms that could lead to the down-regulation of Dicer1 in neuroblastoma. We used computational prediction to identify potential miRs down-regulating Dicer1 in neuroblastoma. One of the miRs that were predicted to target Dicer1 was miR-192. We measured the levels of miR-192 in 43 primary tumors using real time PCR. Following the silencing of miR-192, the levels of dicer1 cell viability, cell proliferation and migration capability were analyzed. Multivariate analysis identified miR-192 as an independent prognostic marker for relapse in neuroblastoma patients (p=0.04). We were able to show through a dual luciferase assay and side-directed mutational analysis that miR-192 directly binds the 3'' UTR of Dicer1 on positions 1232-1238 and 2282-2288. An increase in cell viability, proliferation and migration rates were evident in NB cells transfected with miR-192-mimic. Yet, there was a significant decrease in proliferation when NB cells were transfected with an miR-192-inhibitor We suggest that miR-192 might be a key player in NB by regulating Dicer1 expression.     

Identification of a novel genetically controlled step in mycorrhizal colonization: plant resistance to infection by fungal spores but not extra-radical hyphae

Vesicular arbuscular mycorrhizal fungi infect plants by means of both spores and vegetative hyphae at early stages of symbiosis. Using 2500 M2 fast-neutron-mutagenized seeds of the miniature tomato (Lycopersicon esculentum) cultivar, Micro-Tom, we isolated a mutant, M161, that is able to resist colonization in the presence of Glomus intraradices spores. The myc(-) phenotype of the mutant was stable for nine generations, and found to segregate as a single Mendelian recessive locus. The mutant exhibited morphological and growth-pattern characteristics similar to those of wild-type plants. Alterations of light intensity and day/night temperatures did not eliminate the myc(-) characteristic. Resistance to mycorrhizal fungal infection and colonization was also evident following inoculation with the fungi Glomus mosseae and Gigaspora margarita. Normal colonization of M161 was evident when mutant plants were grown together with arbuscular mycorrhizal-inoculated wild-type plants in the same growth medium. During evaluation of the pre-infection stages in the mutant rhizosphere, spore germination and appressoria formation of G. intraradices were lower by 45 and 70%, respectively, than the rates obtained with wild-type plants. These results reveal a novel, genetically controlled step in the arbuscular mycorrhizal colonization process, governed by at least one gene, which significantly reduces key steps in pre-mycorrhizal infection stages.     

Enhanced levels of free and protein-bound threonine in transgenic alfalfa (Medicago sativa L.) expressing a bacterial feedback-insensitive aspartate kinase gene

Threonine, lysine, methionine, and tryptophan are essential amino acids for humans and monogastric animals. Many of the commonly used diet formulations, particularly for pigs and poultry, contain limiting amounts of these amino acids. One approach for raising the level of essential amino acids is based on altering the regulation of their biosynthetic pathways in transgenic plants. Here we describe the first production of a transgenic forage plant, alfalfa (Medicago sativa L.) with modified regulation of the aspartate-family amino acid biosynthetic pathway. This was achieved by over-expressing the Escherichia coli feedback-insensitive aspartate kinase (AK) in transgenic plants. These plants showed enhanced levels of both free and protein-bound threonine. In many transgenic plants the rise in free threonine was accompanied by a significant reduction both in aspartate and in glutamate. Our data suggest that in alfalfa, AK might not be the only limiting factor for threonine biosynthesis, and that the free threonine pool in this plant limits its incorporation into plant proteins.     

Chlorophyllase is a rate-limiting enzyme in chlorophyll catabolism and is posttranslationally regulated

Chlorophyll is a central player in harvesting light energy for photosynthesis, yet the rate-limiting steps of chlorophyll catabolism and the regulation of the catabolic enzymes remain unresolved. To study the role and regulation of chlorophyllase (Chlase), the first enzyme of the chlorophyll catabolic pathway, we expressed precursor and mature versions of citrus (Citrus sinensis) Chlase in two heterologous plant systems: (1) squash (Cucurbita pepo) plants using a viral vector expression system; and (2) transiently transformed tobacco (Nicotiana tabacum) protoplasts. Expression of full-length citrus Chlase resulted in limited chlorophyll breakdown in protoplasts and no visible leaf phenotype in whole plants, whereas expression of a Chlase version lacking the N-terminal 21 amino acids (ChlaseDeltaN), which corresponds to the mature protein, led to extensive chlorophyll breakdown in both tobacco protoplasts and squash leaves. ChlaseDeltaN-expressing squash leaves displayed a dramatic chlorotic phenotype in plants grown under low-intensity light, whereas under natural light a lesion-mimic phenotype occurred, which was demonstrated to follow the accumulation of chlorophyllide, a photodynamic chlorophyll breakdown product. Full-length and mature citrus Chlase versions were localized to the chloroplast membrane fraction in expressing tobacco protoplasts, where processing of the N-terminal 21 amino acids appears to occur. Results obtained in both plant systems suggest that Chlase functions as a rate-limiting enzyme in chlorophyll catabolism controlled via posttranslational regulation.     

Light-Harvesting Complex Stress-Related Proteins Catalyze Excess Energy Dissipation in Both Photosystems of Physcomitrella patens

Two LHC-like proteins, Photosystem II Subunit S (PSBS) and Light-Harvesting Complex Stress-Related (LHCSR), are essential for triggering excess energy dissipation in chloroplasts of vascular plants and green algae, respectively. The mechanism of quenching was studied in Physcomitrella patens, an early divergent streptophyta (including green algae and land plants) in which both proteins are active. PSBS was localized in grana together with photosystem II (PSII), but LHCSR was located mainly in stroma-exposed membranes together with photosystem I (PSI), and its distribution did not change upon high-light treatment. The quenched conformation can be preserved by rapidly freezing the high-light-treated tissues in liquid nitrogen. When using green fluorescent protein as an internal standard, 77K fluorescence emission spectra on isolated chloroplasts allowed for independent assessment of PSI and PSII fluorescence yield. Results showed that both photosystems underwent quenching upon high-light treatment in the wild type in contrast to mutants depleted of LHCSR, which lacked PSI quenching. Due to the contribution of LHCII, P. patens had a PSI antenna size twice as large with respect to higher plants. Thus, LHCII, which is highly abundant in stroma membranes, appears to be the target of quenching by LHCSR.     

Live sequence charts to model medical information

ABSTRACT: BACKGROUND: Medical records accumulate data concerning patient health and the natural history of disease progression. However, methods to mine information systematically in a form other than an electronic health record are not yet available. The purpose of this study was to develop an object modeling technique as a first step towards a formal database of medical records. METHOD: Live Sequence Charts (LSC) were used to formalize the narrative text obtained during a patient interview. LSCs utilize a visual scenario-based programming language to build object models. LSC extends the classical language of UML message sequence charts (MSC), predominantly through addition of modalities and providing executable semantics. Interobject scenarios were defined to specify natural history event interactions and different scenarios in the narrative text. Result A simulated medical record was specified into LSC formalism by translating the text into an object model that comprised a set of entities and events. The entities described the participating components (i.e., doctor, patient and record) and the events described the interactions between elements. A conceptual model is presented to illustrate the approach. An object model was generated from data extracted from an actual new patient interview, where the individual was eventually diagnosed as suffering from Chronic Fatigue Syndrome (CFS). This yielded a preliminary formal designated vocabulary for CFS development that provided a basis for future formalism of these records. CONCLUSIONS: Translation of medical records into object models created the basis for a formal database of the patient narrative that temporally depicts the events preceding disease, the diagnosis and treatment approach. The LSCs object model of the medical narrative provided an intuitive, visual representation of the natural history of the patient's disease.     

Salivary gland branching morphogenesis: a quantitative systems analysis of the Eda/Edar/NFκB paradigm

Background  

Ectodysplasin-A appears to be a critical component of branching morphogenesis. Mutations in mouse Eda or human EDA are associated with absent or hypoplastic sweat glands, sebaceous glands, lacrimal glands, salivary glands (SMGs), mammary glands and/or nipples, and mucous glands of the bronchial, esophageal and colonic mucosa. In this study, we utilized Eda ^Ta (Tabby) mutant mice to investigate how a marked reduction in functional Eda propagates with time through a defined genetic subcircuit and to test the proposition that canonical NFκB signaling is sufficient to account for the differential expression of developmentally regulated genes in the context of Eda polymorphism.