Regulation, function, and evolution of T2 RNases

T2 RNases have been identified in numerous organisms from plants to animals and even microorganisms. The distribution of this family in almost every organism suggests it may have an important biological function that has being conserved through evolution. In plants, two different subfamilies are defined. S-RNases are involved in pollen rejection during self-incompatible interactions, while S-like RNases are a more diverse group, with not clear function. While expression studies suggest that S-like RNases are involved in many stress responses, including defense against pests and nutrient starvation, and in developmental processes such as senescence, functional studies addressing their biological role are still lacking. In an attempt to fill this gap in knowledge we initiated an analysis of RNS1, a RNase T2 enzyme from Arabidopsis thaliana . We showed that RNS1 transcript and protein are induced during mechanical wounding of the plant and by treatment with the hormone Abscisic Acid (ABA). We found that ABA is part of the RNS1 wounding response pathway; yet in the absence of ABA the RNS1 transcript is still induced. Thus, RNS1 defines a novel wound-response pathway, independent of known wounding signals such as oligogalacturonides, jasmonates, and ethylene. The unusual regulation of RNS1 by novel ABA-dependent and ABA-independent wounding response pathways suggest a unique, yet undefined, function. To further study the function of T2 RNases, we extended our work to other organisms. We found that petunia nectar is rich in RNase activities, and we identified four T2 RNases in Petunia hybrida . Two of these RNases are similar to S-like RNases; while the other two contain characteristics similar to both S- and S-like RNases. The latter two (RNase Phy3 and RNase Phy4 ) also show patterns of regulation consistent with those of nectarins; suggesting they may have a role in petunia nectar defense. While expression analyses can provide clues to understand function of RNases, it was clear that the neither of these potential defense roles would be the one selected to keep this family in almost all organisms. Thus, we carried out phylogenetic analyses in search of conservation patterns that could provide more information about this elusive biological role. To this end we characterized RNase T2 proteins from animals (zebrafish) and plants (rice) and identified RNase T2 genes from a variety of species with fully sequenced genomes. We identified two T2 RNase genes in the Danio rerio (zebrafish) genome. Patterns of regulation for these RNases suggest a possible housekeeping function. Evolutionary analysis of these enzymes along with the emergence of the RNase A family suggest many of the stress related functions preformed by T2 RNases in plants are carried out by the RNase A family in vertebrates; yet retention of at least one T2 RNase suggests an essential function exists. Expression analysis of eight T2 RNases from Oryza sativa (rice) and phylogenetic analysis of plant T2 RNases present in other fully sequenced plant genomes to led us to conclude that plant S-like RNases are divided in two classes; with RNases in Class I showing signs of rapid evolution and a possible function in stress responses (defense, nutrient deficiency), whereas Class II RNases are expressed ubiquitously and phylogenic conservation suggests a possible housekeeping role. This housekeeping role may be conserved for RNase T2 proteins in animals, while Class I functions are carried out by RNase A proteins in vertebrates

Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability. III. The Central Star of Abell 65

A growing number of close binary stars are being discovered among central stars of planetary nebulae. Recent and ongoing surveys are finding new systems and contributing to our knowledge of the evolution of close binary systems. The push to find more systems was largely based on early discoveries which suggested that 10%–15% of all central stars are close binaries. One goal of this series of papers is confirmation and classification of these systems as close binaries and determination of binary system parameters. Here we provide time-resolved multi-wavelength photometry of the central star of Abell 65 as well as further analysis of the nebula and discussion of possible binary–nebula connections. Our results for Abell 65 confirm recent work showing that it has a close, cool binary companion, though several of our model parameters disagree with the recently published values. With our longer time baseline of photometric observations from 1989 to 2009 we also provide a more precise orbital period of 1.0037577 days

PHOTOMETRY OF TWO POORLY STUDIED PLANETARY NEBULAE WITH BINARY CENTRAL STARS

ABSTRACT We have observed the central stars of two planetary nebulae, Abell 65 and Hubble 12, both of which are claimed to be close binary systems. We looked at the differential photometry from these systems in hopes of confirming previous reports of variability caused by close binaries. Binary interaction in a planetary nebula is a possible source of the structure of bi-polar or butterfly PN. We determined that one of the two systems, Abell 65, most likely exhibits variability due to irradiation of a cool companion or deformation of one companion caused by it filing a significant fraction of its Roche Lobe. We cannot confirm the binary classification until a complete light curve is obtained. With Hubble 12, which was claimed to be an eclipsing binary system with an irradiation effect, we found no clear variability indicative of a binary system and recommend that it be removed from the list of known binary central stars

Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability III: The Central Star of Abell 65

A growing number of close binary stars are being discovered among central stars of planetary nebulae. Recent and ongoing surveys are finding new systems and contributing to our knowledge of the evolution of close binary systems. The push to find more systems was largely based on early discoveries which suggested that 10 to 15% of all central stars are close binaries. One goal of this series of papers is confirmation and classification of these systems as close binaries and determination of binary system parameters. Here we provide time-resolved multi-wavelength photometry of the central star of Abell 65 as well as further analysis of the nebula and discussion of possible binary--nebula connections. Our results for Abell 65 confirm recent work showing that it has a close, cool binary companion, though several of our model parameters disagree with the recently published values. With our longer time baseline of photometric observations from 1989--2009 we also provide a more precise orbital period of 1.0037577 days.Comment: Accepted for publication in the Astronomical Journa

Petunia nectar proteins have ribonuclease activity

Plants requiring an insect pollinator often produce nectar as a reward for the pollinator's visitations. This rich secretion needs mechanisms to inhibit microbial growth. In Nicotiana spp. nectar, anti-microbial activity is due to the production of hydrogen peroxide. In a close relative, Petunia hybrida, limited production of hydrogen peroxide was found; yet petunia nectar still has anti-bacterial properties, suggesting that a different mechanism may exist for this inhibition. The nectar proteins of petunia plants were compared with those of ornamental tobacco and significant differences were found in protein profiles and function between these two closely related species. Among those proteins, RNase activities unique to petunia nectar were identified. The genes corresponding to four RNase T2 proteins from Petunia hybrida that show unique expression patterns in different plant tissues were cloned. Two of these enzymes, RNase Phy3 and RNase Phy4 are unique among the T2 family and contain characteristics similar to both S- and S-like RNases. Analysis of amino acid patterns suggest that these proteins are an intermediate between S- and S-like RNases, and support the hypothesis that S-RNases evolved from defence RNases expressed in floral parts. This is the first report of RNase activities in nectar

Zebrafish RNase T2 genes and the evolution of secretory ribonucleases in animals

Background. Members of the Ribonuclease (RNase) T2 family are common models for enzymological studies, and their evolution has been well characterized in plants. This family of acidic RNases is widespread, with members in almost all organisms including plants, animals, fungi, bacteria and even some viruses. While several biological functions have been proposed for these enzymes in plants, their role in animals is unknown. Interestingly, in vertebrates most of the biological roles of plant RNase T2 proteins are carried out by members of a different family, RNase A. Still, RNase T2 proteins are conserved in these animals. Results. As a first step to shed light on the role of animal RNase T2 enzymes, and to understand the evolution of these proteins while co-existing with the RNase A family, we characterized RNase Dre1 and RNase Dre2, the two RNase T2 genes present in the zebrafish (Danio rerio) genome. These genes are expressed in most tissues examined, including high expression in all stages of embryonic development, and their expression corresponds well with the presence of acidic RNase activities in every tissue analyzed. Embryo expression seems to be a conserved characteristic of members of this family, as other plant and animal RNase T2 genes show similar high expression during embryo development. While plant RNase T2 proteins and the vertebrate RNase A family show evidences of radiation and gene sorting, vertebrate RNase T2 proteins form a monophyletic group, but there is also another monophyletic group defining a fish-specific RNase T2 clade. Conclusion. Based on gene expression and phylogenetic analyses we propose that RNase T2 enzymes carry out a housekeeping function. This conserved biological role probably kept RNase T2 enzymes in animal genomes in spite of the presence of RNases A. A hypothetical role during embryo development is also discussed

Regulation, function, and evolution of T2 RNases

T2 RNases have been identified in numerous organisms from plants to animals and even microorganisms. The distribution of this family in almost every organism suggests it may have an important biological function that has being conserved through evolution. In plants, two different subfamilies are defined. S-RNases are involved in pollen rejection during self-incompatible interactions, while S-like RNases are a more diverse group, with not clear function. While expression studies suggest that S-like RNases are involved in many stress responses, including defense against pests and nutrient starvation, and in developmental processes such as senescence, functional studies addressing their biological role are still lacking. In an attempt to fill this gap in knowledge we initiated an analysis of RNS1, a RNase T2 enzyme from Arabidopsis thaliana . We showed that RNS1 transcript and protein are induced during mechanical wounding of the plant and by treatment with the hormone Abscisic Acid (ABA). We found that ABA is part of the RNS1 wounding response pathway; yet in the absence of ABA the RNS1 transcript is still induced. Thus, RNS1 defines a novel wound-response pathway, independent of known wounding signals such as oligogalacturonides, jasmonates, and ethylene. The unusual regulation of RNS1 by novel ABA-dependent and ABA-independent wounding response pathways suggest a unique, yet undefined, function. To further study the function of T2 RNases, we extended our work to other organisms. We found that petunia nectar is rich in RNase activities, and we identified four T2 RNases in Petunia hybrida . Two of these RNases are similar to S-like RNases; while the other two contain characteristics similar to both S- and S-like RNases. The latter two (RNase Phy3 and RNase Phy4 ) also show patterns of regulation consistent with those of nectarins; suggesting they may have a role in petunia nectar defense. While expression analyses can provide clues to understand function of RNases, it was clear that the neither of these potential defense roles would be the one selected to keep this family in almost all organisms. Thus, we carried out phylogenetic analyses in search of conservation patterns that could provide more information about this elusive biological role. To this end we characterized RNase T2 proteins from animals (zebrafish) and plants (rice) and identified RNase T2 genes from a variety of species with fully sequenced genomes. We identified two T2 RNase genes in the Danio rerio (zebrafish) genome. Patterns of regulation for these RNases suggest a possible housekeeping function. Evolutionary analysis of these enzymes along with the emergence of the RNase A family suggest many of the "stress" related functions preformed by T2 RNases in plants are carried out by the RNase A family in vertebrates; yet retention of at least one T2 RNase suggests an essential function exists. Expression analysis of eight T2 RNases from Oryza sativa (rice) and phylogenetic analysis of plant T2 RNases present in other fully sequenced plant genomes to led us to conclude that plant S-like RNases are divided in two classes; with RNases in Class I showing signs of rapid evolution and a possible function in stress responses (defense, nutrient deficiency), whereas Class II RNases are expressed ubiquitously and phylogenic conservation suggests a possible housekeeping role. This housekeeping role may be conserved for RNase T2 proteins in animals, while Class I functions are carried out by RNase A proteins in vertebrates.</p

Changes in microbial communities of a passive coal mine drainage bioremediation system

Drainage from abandoned mines is one factor greatly affecting the streams and vegetation in and around Pittsburgh and the Appalachian Mountains where coal mining occurred. This drainage may be more acidic, alkaline, or metal based. Different methods for remediation exist. Passive remediation is one method used to naturally allow the metals to precipitate out and aid in cleaning up the water. The goal of this study is to sample different holding ponds in a sequential passive remediation system and determine microbial communities present at each site of an abandoned coal mine drainage (CMD) site. 16s rRNA gene sequencing of the sediment indicated the most abundant phyla at each of the 5 ponds and wetlands area included Proteobacteria (36-43%), Bacteroidetes (12-37%), Firmicutes (3-11%), and Verrucomicrobia (6-11%). Analysis of genera between the first, and most polluted pond includes Solitalea, Pedosphaera, and Rhodocyclus; while the microbial community from the wetlands site at the end of the remediation system included Ignavibacterium, Pelotomaculum, and Petrimonas. The results of our microbial community composition study of sediment from a passive treatment system are in line with organisms commonly found in sediment regardless of iron oxide precipitation, while others are preferentially found in the less polluted wetlands site.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Recognizing Recreational Water Exposure and Habituating HAB Surveillance in ESSENCE

ObjectiveUse ESSENCE to create a sustainable process for identifying ED and urgent care visits that may be related to harmful algal bloom exposure in Oregon.IntroductionHarmful algal blooms (HABs) consist of colonies of prokaryotic photosynthetic bacteria algae that can produce harmful toxins. The toxins produced by HABs are considered a One Health issue. HABs can occur in all types of water (fresh, brackish, and salt water) and are composed of cyanobacteria or microalgae. As the climate changes, so do many of the factors that contribute to the growth of HABs, which in turn, can increase the incidence of HAB-related illness in humans.There are three main pathways that HAB toxins can affect human health: dermal, gastrointestinal (GI), and neurological. Swimming in or consuming contaminated water and eating contaminated shellfish are ways to develop HAB-related illnesses. Contact with cells from a bloom while recreating can cause a rash on the body. Most commonly, HAB-related illnesses present with GI symptoms that resemble food poisoning and can affect the liver. Rarely, HABs that produce cyanotoxins can present with neurological symptoms.Issuing and lifting freshwater HAB advisories is within the preview of the Environmental Public Health section at the Oregon Public Health Division. However, most water bodies in the state are not monitored. Because of this, syndromic surveillance was considered as a potentially useful source of HAB exposure information, and the Oregon ESSENCE team was asked to develop a query to help monitor HAB-related complaints.MethodsPreliminary research was done on HABs and the associated health issues, and past advisories were examined to identify locations of interest. Next, keywords and symptoms were evaluated.Initially, the objective was to create a single query for HAB syndromic surveillance, but it became evident that multiple queries would have to be developed to fully encompass the various types of HAB-related illnesses: GI, neurological, and rash.Most commonly Oregon ESSENCE uses chief complaint and discharge diagnosis (CCDD) queries. However, the ICD-10 codes relating to HABs are not widely used, with only two occurrences since June 2015. It was determined that using the already established ESSENCE syndromes of Neuro, GI, and Rash would be most useful. To make the queries HAB-specific, an additional exposure element needed to be added. Exposures to HABs that are of interest occur in recreational freshwater sources. After running this query in the CCDD field, it was determined that the triage note field would yield better results. This is because this field often includes the patient’s verbatim complaints. This produced higher quality results, and a seasonal curve of cases could be seen in the historic data.Since the microcystin threshold for illness is significantly lower for pets; and a permanent HAB alert in southern Oregon was established after several dogs died from drinking contaminated water, tracking neurological cases that followed canine illness was investigated. A free-text triage note query was developed for patients mentioning dogs, and it was combined with the ESSENCE Neuro syndrome. After several attempts, it was clear that this would not be helpful for surveillance of HAB-related illnesses.Ultimately, four query configurations were developed to monitor HAB-related illness. Most importantly, a free-text recreational water query was developed to stand alone and then be paired with three distinct ESSENCE syndromes.Recreational water query text: (, (, ^ lake^ ,andnot, (, ^road^ ,or, ^rd^ ,or, ^sky^ ,or, ^oswego^ ,or, ^view^ ,) ,) ,or, ^swim^ ,or, (, ^ river ^ ,andnot, (, ^driver^, or, ^hood^ ,or, ^rd^ ,or, ^road^ ,or, ^three^ ,) ,) ,or, ^ boat^ ,) ,andnot, ^feels like^All queries were compiled into a myESSENCE page that could be shared for easy monitoring by all members of the team (Figure 1).ResultsThe ESSENCE team monitored the HAB myESSENCE page. The monitoring period for this project stretched from May to early August (MMWR weeks 19-31). Motoring was often informed by HAB alerts and required looking closely at individual visits. Over this time, the number of recreational water related visits varied, but the average was approximately 110 visits a week. This techniques also helped identify cases possibly related to unreported blooms. The months of June and July saw 15 specific cases that were potentially due to HAB exposure. These cases were highlighted and forwarded to Environmental Public Health for investigation.ConclusionsThis process helped refine the use of the triage note field when constructing keyword queries. While not all Oregon facilities provide triage notes, using specific terms allows ESSENCE users to search for words that may not be included in chief complaints. This is most be useful when searching for specific places or events. With further analysis, users can see what chief complaints are most likely to occur in conjunction with specific exposures. Moving forward, the development of a recreational water query has proven to be useful beyond the scope of this HAB project. Alternative versions of this query have been used in other contexts.ReferencesHarmful Algal Bloom (HAB)-Associated Illness. (2017, June 01). Retrieved August 01, 2017, from https://www.cdc.gov/habs/index.htm

Petunia nectar proteins have ribonuclease activity

Plants requiring an insect pollinator often produce nectar as a reward for the pollinator's visitations. This rich secretion needs mechanisms to inhibit microbial growth. In Nicotiana spp. nectar, anti-microbial activity is due to the production of hydrogen peroxide. In a close relative, Petunia hybrida, limited production of hydrogen peroxide was found; yet petunia nectar still has anti-bacterial properties, suggesting that a different mechanism may exist for this inhibition. The nectar proteins of petunia plants were compared with those of ornamental tobacco and significant differences were found in protein profiles and function between these two closely related species. Among those proteins, RNase activities unique to petunia nectar were identified. The genes corresponding to four RNase T2 proteins from Petunia hybrida that show unique expression patterns in different plant tissues were cloned. Two of these enzymes, RNase Phy3 and RNase Phy4 are unique among the T2 family and contain characteristics similar to both S- and S-like RNases. Analysis of amino acid patterns suggest that these proteins are an intermediate between S- and S-like RNases, and support the hypothesis that S-RNases evolved from defence RNases expressed in floral parts. This is the first report of RNase activities in nectar.This is an article from Journal of Experimental Botany 61 (2010): 2951, doi:10.1093/jxb/erq119. Posted with permission.</p