A Single Amino Acid Substitution in the Intervening Region of 129K Protein of Cucumber Green Mottle Mosaic Virus Resulted in Attenuated Symptoms.

Cucumber green mottle mosaic virus (CGMMV), a member of the genus Tobamovirus, is a major threat to economically important cucurbit crops worldwide. An attenuated strain (SH33b) derived from a severe strain (SH) of CGMMV caused a reduction in the viral RNA accumulation and the attenuation of symptoms, and it has been successfully used to protect muskmelon plants against severe strains in Japan. In this study, we compared GFP-induced silencing suppression by the 129K protein and the methyltransferase domain plus intervening region (MTIR) of the 129K protein between the SH and SH33b strains, respectively. As a result, silencing suppression activity (SSA) in the GFP-silenced plants was inhibited efficiently by the MTIR and 129K protein of SH strain, and it coincided with drastically reduced accumulation of GFP-specific small interfering RNAs (siRNAs) but not by that of SH33b strain. Furthermore, analyses of siRNA binding capability (SBC) by the MTIR of 129K protein and 129K protein using electrophoretic mobility shift assay revealed that SBC was found with the MTIR and 129K protein of SH but not with that of SH33b, suggesting that a single amino acid mutation (E to G) in the MTIR is responsible for impaired SSA and SBC of SH33b. These data suggest that a single amino acid substitution in the intervening region of 129K protein of CGMMV resulted in attenuated symptoms by affecting RNA silencing suppression.

Vascular architecture in the bacteriogenic light organ of Euprymna tasmanica (Cephalopoda: Sepiolidae).

Symbiosis between southern dumpling squid, Euprymna tasmanica (Cephalopoda: Sepiolidae), and its luminescent symbiont, the bacterium Vibrio fischeri, provides an experimentally tractable system to examine interactions between the eukaryotic host and its bacterial partner. Luminescence emitted by the symbiotic bacteria provides light for the squid in a behavior termed "counter-illumination," which allows the squid to mask its shadow amidst downwelling moonlight. Although this association is beneficial, light generated from the bacteria requires large quantities of oxygen to maintain this energy-consuming reaction. Therefore, we examined the vascular network within the light organ of juveniles of E. tasmanica with and without V. fischeri. Vessel type, diameter, and location of vessels were measured. Although differences between symbiotic and aposymbiotic squid demonstrated that the presence of V. fischeri does not significantly influence the extent of vascular branching at early stages of symbiotic development, these finding do provide an atlas of blood vessel distribution in the organ. Thus, these results provide a framework to understand how beneficial bacteria influence the development of a eukaryotic closed vascular network and provide insight to the evolutionary developmental dynamics that form during mutualistic interactions.

Dental findings in a child with osteopathia striata with cranial sclerosis (OS-CS): a case report.

The dental management of an 8-year-old girl with osteopathia striata with cranial sclerosis (OS-CS) is described. The girl presented with various oral abnormalities. The aim of this case report was to describe in detail the dental findings in a patient with OC-CS and the precautions to be taken when planning treatment. In the present case, many dental anomalies, such as delayed eruption of the permanent teeth, obliteration of the dental pulp, short roots, fused roots and taurodontism, were detected. In patients with OS-CS, routine dental care from an early stage is recommended to manage this anomaly properly.

Involvement of glucocorticoid receptor on hyperpyrexia induced by methamphetamine administration.

UNLABELLED: We have investigated the involvement of glucocorticoid on methamphetamine (MA) induced hyperpyrexia using a bio-telemetric system. A significant level of hyperpyrexia was observed in MA administered rats. In contrast, increase of body temperature was suppressed by adrenalectomy or by the administration of RU-486, an antagonist of the glucocorticoid receptor. These data suggest that the glucocorticoid receptor may be involved in hyperpyrexia induced by MA. KEYWORDS: methamphetamine - hyperpyrexia - glucocorticoid - corticosterone.

Phylogeographical patterns among Mediterranean sepiolid squids and their Vibrio symbionts: environment drives specificity among sympatric species.

Bobtail squid from the genera Sepiola and Rondeletiola (Cephalopoda: Sepiolidae) form mutualistic associations with luminous Gram-negative bacteria (Gammaproteobacteria: Vibrionaceae) from the genera Vibrio and Photobacterium. Symbiotic bacteria proliferate inside a bilobed light organ until they are actively expelled by the host into the surrounding environment on a diel basis. This event results in a dynamic symbiont population with the potential to establish the symbiosis with newly hatched sterile (axenic) juvenile sepiolids. In this study, we examined the genetic diversity found in populations of sympatric sepiolid squid species and their symbionts by the use of nested clade analysis with multiple gene analyses. Variation found in the distribution of different species of symbiotic bacteria suggests a strong influence of abiotic factors in the local environment, affecting bacterial distribution among sympatric populations of hosts. These abiotic factors include temperature differences incurred by a shallow thermocline, as well as a lack of strong coastal water movement accompanied by seasonal temperature changes in overlapping niches. Host populations are stable and do not appear to have a significant role in the formation of symbiont populations relative to their distribution across the Mediterranean Sea. Additionally, all squid species examined (Sepiola affinis, S. robusta, S. ligulata, S. intermedia, and Rondeletiola minor) are genetically distinct from one another regardless of location and demonstrate very little intraspecific variation within species. These findings suggest that physical boundaries and distance in relation to population size, and not host specificity, are important factors in limiting or defining gene flow within sympatric marine squids and their associated bacterial symbionts in the Mediterranean Sea.

A fatal case of severe methemoglobinemia presumably due to chlorate ingestion.

A fatal case due to severe methemoglobinemia is presented. A male in his forties was found unconscious in his house and, despite intensive care, death was confirmed approximately 11 hours later. Toxicological analysis using ion chromatography revealed the presence of chlorate in the stomach contents. However, chlorate was not detected in the blood, and no other drugs or ethanol were detected in the blood either. We concluded that the cause of death was presumably due to chlorate poisoning, based on the results of the autopsy and the toxicological examination.

BIOLOGICAL PROPERTIES (IN VITRO) EXHIBITED BY FREE-LIVING AND SYMBIOTIC VIBRIO ISOLATES.

Adhesion and biofilm forming ability of symbiotic bacteria play a crucial role in host colonization and tissue infection. Bacteria benefit by adhering to their host in a manner that allows them to successfully maintain contact for the exchange of nutrients, hormones, or other necessary products. This study examined pili morphology, motility, and biofilm formation exhibited by Vibrio fischeri strains (free-living and symbiotic). Since these symbiotic factors contribute in some fashion to the interaction between V. fischeri and their squid host, variation between strains may be a contributing factor that leads to specificity among different hosts. V. fischeri strains examined in this study demonstrated considerable variation in their biological properties when observed in vitro. In addition to differences observed between strains isolated from several different host species, we observed variation between strains isolated from the same host species from diverse geographical locations. This study suggests that subtle differences in the biological properties of closely related V. fischeri strains may influence the nature of the interaction among V. fischeri and their sepiolid hosts.

ULTRASTRUCTURE OF LIGHT ORGANS OF LOLIGINID SQUIDS AND THEIR BACTERIAL SYMBIONTS: A NOVEL MODEL SYSTEM FOR THE STUDY OF MARINE SYMBIOSES.

The class Cephalopoda (Phylum Mollusca), encompassing squids and octopuses, contains multiple species that are characterized by the presence of specialized organs known to emit light. These complex organs have a variety of morphological characteristics ranging from groups of simple, light-producing cells, to highly specialized organs (light organs) with cells surrounded by reflectors, lenses, light guides, color filters, and muscles. Bacteriogenic light organs have been well characterized in sepiolid squids, but a number of species in the family Loliginidae are also known to contain bacteriogenic light organs. Interest in loliginid light organ structure has recently arisen because of their potential as ecological niches for Vibrio harveyi, a pathogenic marine bacterium. This also implies the importance of loliginid light organs as reservoirs for V. harveyi persistence in the ocean. The present study utilized transmission and scanning electron microscopy to characterize the morphology of loliginid light organs and determined the location of bacterial symbiont cells within the tissue. It was determined that the rod-shaped loliginid symbionts lack flagella, as similarly observed in other light organ-associated bacteria. Also, the interaction of individual cells to light organ tissue is not as defined as reported for other squid-Vibrio systems. In addition, SEM observations show the presence of two pores leading to the bacterial chamber. Data presented here offer support for the hypothesis of environmental transfer of bacterial symbionts in loliginid squids.

THE EVOLUTIONARY ECOLOGY OF A SEPIOLID SQUID-VIBRIO ASSOCIATION: FROM CELL TO ENVIRONMENT.

Mutualistic relationships between bacteria and their eukaryotic hosts have existed for millions of years, and such associations can be used to understand the evolution of these beneficial partnerships. The symbiosis between sepiolid squids (Cephalopoda: Sepiolidae), and their Vibrio bacteria (gamma Proteobacteria: Vibrionaceae), has been a model system for over 20 years, giving insight as to the specificity of the association, and whether the interactions themselves give rise to such finely tuned dialog. Since the association is environmentally transmitted, selection for specificity can evolve from a number of factors; abiotic (temperature, salinity), as well as biotic (host species, receptors, cell/cell interactions). Here, we examine the transition between these forces effecting the symbiosis, and pose possible explanations as to why this association offers many attributes for understanding the role of symbiotic competence.

Deciphering Evolutionary Mechanisms Between Mutualistic and Pathogenic Symbioses.

The continuum between mutualistic and pathogenic symbioses has been an underlying theme for understanding the evolution of infection and disease in a number of eukaryotic-microbe associations. The ability to monitor and then predict the spread of infectious diseases may depend upon our knowledge and capabilities of anticipating the behavior of virulent pathogens by studying related, benign symbioses. For instance, the ability of a symbiotic species to infect, colonize, and proliferate efficiently in a susceptible host will depend on a number of factors that influence both partners during the infection. Levels of virulence are not only affected by the genetic and phenotypic composite of the symbiont, but also the life history, mode(s) of transmission, and environmental factors that influence colonization, such as antibiotic treatment. Population dynamics of both host and symbiont, including densities, migration, as well as competition between symbionts will also affect infection rates of the pathogen as well as change the evolutionary dynamics between host and symbiont. It is therefore important to be able to compare the evolution of virulence between a wide range of mutualistic and pathogenic systems in order to determine when and where new infections might occur, and what conditions will render the pathogen ineffective. This perspective focuses on several symbiotic models that compare mutualistic associations to pathogenic forms and the questions posed regarding their evolution and radiation. A common theme among these systems is the prevailing concept of how heritable mutations can eventually lead to novel phenotypes and eventually new species.