Suppression of tumorigenicity by the IncW R plasmid pSa in Agrobacterium tumefaciens

Summary The effect of the IncW R plasmid, pSa, on tumorigenicity and on the expression and maintenance of the Ti plasmid in tumorigenic strains of A. tumefaciens was determined. Plasmid pSa could be transferred into and stably maintained by both octopine-and nopaline-utilizing A. tumefaciens strains. The R plasmid had no effect on Ti plasmid maintenance or on Ti plasmid functions, such as octopine utilization or conjugal bacterial transfer. However, A. tumefaciens strains harboring both the R plasmid and the Ti plasmid in most instances failed to induce tumors on a number of plant species. This effect on tumorigenicity is specific to pSa. When pSa is cured from the A. tumefaciens transconjugants or when their Ti plasmids are genetically transferred to an appropriate recipient, the resultant strains lacking the R plasmid regain tumorigenicity. Restriction endonuclease analysis of plasmid DNA isolated from transconjugants harboring pSa showed no difference in Ti plasmid cleavage patterns when compared to plasmid DNA isolated from the tumorigenic parent strain. These results indicate that pSa does not induce detectable permanent genetic alteration of the Ti plasmid. Rather, it appears that the R plasmid suppresses some Ti plasmid function(s) necessary for tumorigenicity.     

Characterization and kinetics of isoenzymes of pyruvate kinase from developing castor bean endosperm

Isozymes of pyruvate kinase (PK) have been isolated from developing castor bean endosperm. One isozyme, PK_c, is localized in the cytosol, and the other, PK_p, is in the plastid. Both isozymes need monovalent and divalent cations for activity, requirements which can be filled by K⁺ and Mg²⁺. Both isozymes are inhibited by citrate, pyruvate, and ATP. PK_c has a much broader pH profile than PK_p and is also more stable. Both have the same K_m (0.05 millimolar) for PEP, but PK_p has a 10-fold higher K_m (0.3 millimolar) for ADP than PK_c (0.03 millimolar). PK_c also has a higher affinity for alternate nucleotide substrates than PK_p. The two isozymes have different kinetic mechanisms. Both have an ordered sequential mechanism and bind phosphoenolpyruvate before ADP. However, the plastid isozyme releases ATP first, whereas pyruvate is the first product released from the cytosolic enzyme. The properties of the two isozymes are similar to those of their counterparts in green tissue.     

Treatment of hypertonicity in muscles of lip retraction

An EMG biofeedback program was developed for a 56-year-old Parkinsonism patient who exhibited pathological lip hypertonia and retraction. The program was designed to achieve the following goals: (1) to demonstrate a reduction in postural lip hypertonicity and (2) to demonstrate a reduction in lip hypertonicity during a series of increasingly complex speech activities. To achieve the first goal, contrastive tasks of full contraction and relaxation were utilized. Each posture was sustained while voltage measurements were made at specifici intervals. Procedures to modify lip retraction during speech included five tasks in which the patient was to monitor the audio feedback signal. The tasks involved: prolongation of a neutral vowel, consonant-vowel combinations, monosyllabic words, sentences, and a paragraph-reading task. Data collected over six biofeedback sessions are presented. Trend analyses showed consistent muscular reduction within each task. The following explanations for the decrease in the patient's hypertonicity were discussed: (1) reduction of anisometric contraction, (2) reduction of isometric contraction, (3) relearning of agonistic-antagonistic muscle balance.This research was supported in part by the University of Tennessee Neuropathology Services Program.     

Resultados comparativos de la reaccion intradermica a la tuberculina - histoplasmina- coccidioidina en Tuberculosos

Mycopathologia - Se estudiaron los resultados comparativos de las reacciones intradérmicas a la Tuberculina, Histoplasmina y Coccidioidina, practicadas simultáneamente a 644 enfermos...     

Inositol‐requiring enzyme‐1 regulates phosphoinositide signaling lipids and macrophage growth

The ER‐bound kinase/endoribonuclease (RNase), inositol‐requiring enzyme‐1 (IRE1), regulates the phylogenetically most conserved arm of the unfolded protein response (UPR). However, the complex biology and pathology regulated by mammalian IRE1 cannot be fully explained by IRE1’s one known, specific RNA target, X box‐binding protein‐1 (XBP1) or the RNA substrates of IRE1‐dependent RNA degradation (RIDD) activity. Investigating other specific substrates of IRE1 kinase and RNase activities may illuminate how it performs these diverse functions in mammalian cells. We report that macrophage IRE1 plays an unprecedented role in regulating phosphatidylinositide‐derived signaling lipid metabolites and has profound impact on the downstream signaling mediated by the mammalian target of rapamycin (mTOR). This cross‐talk between UPR and mTOR pathways occurs through the unconventional maturation of microRNA (miR) 2137 by IRE1’s RNase activity. Furthermore, phosphatidylinositol (3,4,5) phosphate (PI(3,4,5)P₃) 5‐phosphatase‐2 (INPPL1) is a direct target of miR‐2137, which controls PI(3,4,5)P₃ levels in macrophages. The modulation of cellular PI(3,4,5)P₃/PIP₂ ratio and anabolic mTOR signaling by the IRE1‐induced miR‐2137 demonstrates how the ER can provide a critical input into cell growth decisions.     

Optimizing canopy‐forming algae conservation and restoration with a new herbivorous fish deterrent device

The role of herbivorous fish in threatening marine forests of temperate seas has been generally overlooked. Only recently, the scientific community has highlighted that high fish herbivory can lead to regime shifts from canopy‐forming algae to less complex turf communities. Here, we present an innovative herbivorous fish deterrent device (DeFish), which can be used for conservation and restoration of marine forests. Compared to most traditional fish exclusion systems, such as cages, the DeFish system does not need regular cleaning and maintenance, making it more cost‐efficient. Resistance of DeFish was tested by installing prototypes at different depths in the French Riviera and in Montenegro: more than 60% of the devices endured several years without maintenance, even if most of them were slightly damaged in the exposed site in Montenegro. The efficacy of DeFish in limiting fish herbivory was tested by an exclusion experiment on Cystoseira amentacea in the French Riviera. In a few months, the number of fish bite marks on the seaweed was decreased, causing a consequent increase in algal length. The device here presented has been conceived for Mediterranean canopy‐forming algae, but the same concept can be applied to other species vulnerable to fish herbivory, such as kelps or seagrasses. In particular, the DeFish design could be improved using more robust and biodegradable materials. Innovative engineering systems, such as DeFish, are expected to become useful tools in the conservation and restoration of marine forests, to complement other practices including active reforestation, herbivore regulation, and regular monitoring of their status.     

Response of transgenic tobacco overexpressing the CchGLP gene to cadmium and aluminium: phenotypic and microRNAs expression changes

Physiology and Molecular Biology of Plants - Transgenic tobacco (N. tabacum cv. Xanthi nc) expressing Capsicum chinense CchGLP gene that encodes an Mn-SOD, constitutively produces hydrogen...     

Contrasting the seasonal and elevational prevalence of generalist avian haemosporidia in co‐occurring host species

Understanding the ecology and evolution of parasites is contingent on identifying the selection pressures they face across their infection landscape. Such a task is made challenging by the fact that these pressures will likely vary across time and space, as a result of seasonal and geographical differences in host susceptibility or transmission opportunities. Avian haemosporidian blood parasites are capable of infecting multiple co‐occurring hosts within their ranges, yet whether their distribution across time and space varies similarly in their different host species remains unclear. Here, we applied a new PCR method to detect avian haemosporidia (genera Haemoproteus, Leucocytozoon, and Plasmodium) and to determine parasite prevalence in two closely related and co‐occurring host species, blue tits (Cyanistes caeruleus, N = 529) and great tits (Parus major, N = 443). Our samples were collected between autumn and spring, along an elevational gradient in the French Pyrenees and over a three‐year period. Most parasites were found to infect both host species, and while these generalist parasites displayed similar elevational patterns of prevalence in the two host species, this was not always the case for seasonal prevalence patterns. For example, Leucocytozoon group A parasites showed inverse seasonal prevalence when comparing between the two host species, being highest in winter and spring in blue tits but higher in autumn in great tits. While Plasmodium relictum prevalence was overall lower in spring relative to winter or autumn in both species, spring prevalence was also lower in blue tits than in great tits. Together, these results reveal how generalist parasites can exhibit host‐specific epidemiology, which is likely to complicate predictions of host–parasite co‐evolution.