Legionella sainthelensi: a new species of Legionella isolated from water near Mt. St. Helens

Six strains of a new species, Legionella sainthelensi, were isolated from freshwater in areas affected by the volcanic eruptions of Mt. St. Helens in the state of Washington. Strains of L. sainthelensi are culturally and biochemically similar to other legionellae. They grow on buffered charcoal yeast agar but not on media that lack cysteine. They are gram-negative, nonsporeforming, motile rods that are positive in reactions for catalase, oxidase, gelatin liquefaction, and beta-lactamase. They are negative in reactions for urease, hydrolysis of hippurate, reduction of nitrates, fermentation of glucose, and blue-white autofluorescence. Their cell wall fatty acid composition is qualitatively similar to those of other legionellae, with 50 to 62% branched-chain fatty acids. They contain the isobranched-chain 14- and 16-carbon acids and anteisobranched-chain 15- and 17-carbon acids and relatively large amounts of straight-chain 16-carbon acid. All strains of L. sainthelensi contain approximately equal amounts of ubiquinones Q9, Q10, Q11, and Q12, a pattern similar to those of Legionella bozemanii, Legionella dumoffi, and Legionella longbeachae. Serological cross-reactions were observed between L. sainthelensi, both serogroups of L. longbeachae, and Legionella oakridgensis. Three strains of L. sainthelensi were greater than 90% related by DNA hybridization. The type strain of L. sainthelensi, Mt. St. Helens 4, was 36% related to the type strain of L. longbeachae and 3 to 14% related to the other nine described Legionella species.     

Deoxyribonucleic acid relatedness inYersinia enterocolitica andYersinia enterocolitica-like organisms

Yersinia enterocolitica andY. enterocolitica-like strains were characterized by DNA relatedness. These strains formed four distinct DNA relatedness groups: (i) the 5 classical biotypes ofY. enterocolitica sensu stricto as designated by Wauters; (ii) strains that are rhamnose positive and also positive in tests for melibiose, α-methyl-d-glucoside, raffinose, and Simmons' citrate; (iii) strains that are rhamnose positive but negative in tests for melibiose, α-methyl-d-glucoside, and raffinose; (iv) sucrose-negative, Voges-Proskauer-negative, trehalose-positive strains.     

DNA relatedness among species of Enterobacter and Serratia.

Species of Enterobacter and Serratia were examined for deoxyribonucleic acid relatedness to Klebsielleae, to atypical erwiniae, and to other members of Enterobacteriaceae. Deoxyribonucleic acid hybridization and then hydroxyapatite chromatography was the technique used to assess relatedness. Strains of Enterobacter cloacae formed two separate hybridization groups that correlate with the presence or absence of yellow pigment. Pigmented E. cloacae were 75-100% related, but they were only 40-50% related to unpigmented strains. Conversely, unpigmented strains were 70% or more related but were only 40-50% related to the pigmented strains. Both pigmented and unpigmented E. cloacae were 40-45% related to Enterobacter aerogenes and klebsiellae, and 20-30% related to Serratia species and Enterobacter hafniae. Atypical erwiniae were highly related to E. cloacae. Serratia marcescens strains formed one closely related group. Serratia liquefaciens strains formed a single, more disperse, relatedness group, as did isolates of Serratia rubidaea. These species were related throughout a substantial portion of their genomes. A group of lysine-positive "Citrobacter-like" strains were 40-50% related to Serratia species. Only four E. hafniae strains were tested. Two of these were highly related, while the other two were only 50% related to the reference strain. Enterobacter hafniae was only 15-20% related to other Enterobacteriaceae.     

Variability in host plant resistance of Sorghum to Striga Hermonthica infestation in West Africa

Fourteen elite sorghum lines were evaluated for their resistance to Striga hermonthica at three locations in Nigeria and Mali. Results showed that many of the lines especially MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64 (Keninkédié) and the check SRN 39 remained resistant to Striga in all locations with low emerged Striga counts, while SAMSORG 14 had the highest Striga infestation in all locations. Considerable variation in reaction to Striga infestation was observed on Séguètana, 97-SB-F5DT-63 (Wasa), 97-SB-F5DT-65, CMDT 38, CMDT 39 and CMDT 45 which were susceptible to Striga at Samaru, Nigeria but were resistant to Striga at both locations in Mali. Based on low Striga resistance and high grain yield, lines MALISOR 84-1, SAMSORG 41, 97-SB-F5DT-64, 97-SB-F5DT-65, CMDT 39 and SAMSORT 14 have been nominated for wider evaluation across more West African countries.     

Two common nonsynonymous paraoxonase 1 (<Emphasis Type="Italic">PON1</Emphasis>) gene polymorphisms and brain astrocytoma and meningioma

Background  

Human serum paraoxonase 1 (PON1) plays a major role in the metabolism of several organophosphorus compounds. The enzyme is encoded by the polymorphic gene PON1, located on chromosome 7q21.3. Aiming to identify genetic variations related to the risk of developing brain tumors, we investigated the putative association between common nonsynonymous PON1 polymorphisms and the risk of developing astrocytoma and meningioma.     

Long-term effects of graduated compression stockings on cardiorespiratory performance

The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) – a 5-min maximal effort run in order to determine the participants’ maximal aerobic speed; and tests 2) and 3) – a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLACEBO stockings at random. Cardiorespiratory parameters (minute ventilation, heart rate, relative oxygen consumption, relative carbon dioxide production, ventilatory equivalents for oxygen and carbon dioxide, and oxygen pulse) were measured. Before each test in the laboratory, the participants trained with the randomly assigned stockings (GCS or PLACEBO) for three weeks. No significant differences between GCS and PLACEBO were found in any of the cardiorespiratory parameters. In conclusion, the present study provides evidence that running with GCS for three weeks does not influence cardiorespiratory parameters in recreational runners.     

Legionella anisa: a new species of Legionella isolated from potable waters and a cooling tower.

Between March 1980 and June 1981, five strains of Legionella-like organisms were isolated from water. Four were recovered from potable water collected from hospitals in Chicago, Ill., and Los Angeles, Calif., during outbreaks of nosocomial legionellosis. The fifth strain was isolated from water collected from an industrial cooling tower in Jamestown, N.Y. The strains exhibited biochemical reactions typical of Legionella species and were gram-negative motile rods which grew on buffered charcoal-yeast extract agar but not on blood agar, required cysteine, and were catalase positive, urease negative, nitrate negative, hippurate negative, and nonfermentative. All strains were positive for oxidase and beta-lactamase and produced a brown, diffusible pigment. Of the five strains, four exhibited blue-white autofluorescence under long-wavelength UV light. The fatty-acid composition and ubiquinone content of these strains were consistent with those of other Legionella species. Direct fluorescent-antibody examination of the five strains with conjugates to previously described Legionella species demonstrated no cross-reactions except with the conjugates to L. longbeachae serogroup 2 and L. bozemanii serogroup 2. Four strains gave a 4+ reaction to the L. longbeachae serogroup 2 conjugate and the fifth strain gave a 1+ reaction. Each of the five strains gave a 4+ reaction with the conjugate to L. bozemanii serogroup 2. DNAs from the five strains were highly related (84 to 99%) and showed 5 to 57% relatedness to other Legionella species. These strains constitute a new species in the genus Legionella, and the name Legionella anisa sp. nov. is proposed. The type strain of L. anisa is WA-316-C3 (ATCC 35292).     

Erwinia persicinus, a new species isolated from plants

Five strains of a gram-negative, oxidase-negative, facultatively anaerobic, fermentative, motile, rod-shaped bacterium with the general characteristics of the family Enterobacteriaceae were isolated from tomatoes (three strains), a banana, and a cucumber. All of the strains produced a water-soluble pink pigment. As determined by DNA hybridization (hydroxyapatite method) these five strains were 85 to 100% related in 60 and 75 degrees C reactions, and related sequences exhibited 1% or less base sequence divergence, indicating that the organisms are members of a single species. These bacteria were most closely related to Erwinia rhapontici (68 to 72% at 60 degrees C, 42 to 44% at 75 degrees C, 10.5% divergence) and to hybridization group VIII in the Enterobacter agglomerans (Pantoea agglomerans, Erwinia herbicola) complex (64% at 60 degrees C, 32% at 75 degrees C, 14.5% divergence). Phenotypic differentiation from Erwinia rhapontici, which also produces a water-soluble pink pigment, is based on negative reactions by the new species in tests for methyl red, N-acetylglucosamine, DL-tartrate assimilation, and acid production from amygdalin, dulcitol, D-fucose, beta-gentiobiose, alpha-methyl-D-glucoside, glycerol, D-lyxose, melezitose, D-turanose, xylitol, and D-xylose and a positive reaction for acetoin (Voges-Proskauer test). On the basis of these data, the name Erwinia persicinus is proposed for the new organism. The type strain is strain HK 204 (= AJ 2716 = CDC 9108-82 = IAM 12843 = JCM 3704 = ATCC 35998).     

Intragenic duplication and divergence in the spectrin superfamily of proteins

Many structural, signaling, and adhesion molecules contain tandemly repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin superfamily of F-actin-crosslinking proteins contains an array of triple alpha-helical motifs (spectrin repeats). We present here the complete sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H). The sequence of beta H supports the origin of alpha- and beta-spectrins from a common ancestor, and we present a novel model for the origin of the spectrins from a homodimeric actin-crosslinking precursor. The pattern of similarity between the spectrin repeat units indicates that they have evolved by a series of nested, nonuniform duplications. Furthermore, the spectrins and dystrophins clearly have common ancestry, yet the repeat unit is of a different length in each family. Together, these observations suggest a dynamic period of increase in repeat number accompanied by homogenization within each array by concerted evolution. However, today, there is greater similarity of homologous repeats between species than there is across repeats within species, suggesting that concerted evolution ceased some time before the arthropod/vertebrate split. We propose a two-phase model for the evolution of the spectrin repeat arrays in which an initial phase of concerted evolution is subsequently retarded as each new protein becomes constrained to a specific length and the repeats diverge at the DNA level. This evolutionary model has general applicability to the origins of the many other proteins that have tandemly repeated motifs.      

Higher‐order assemblies of oligomeric cargo receptor complexes form the membrane scaffold of the Cvt vesicle

Selective autophagy is the mechanism by which large cargos are specifically sequestered for degradation. The structural details of cargo and receptor assembly giving rise to autophagic vesicles remain to be elucidated. We utilize the yeast cytoplasm‐to‐vacuole targeting (Cvt) pathway, a prototype of selective autophagy, together with a multi‐scale analysis approach to study the molecular structure of Cvt vesicles. We report the oligomeric nature of the major Cvt cargo Ape1 with a combined 2.8 Å X‐ray and negative stain EM structure, as well as the secondary cargo Ams1 with a 6.3 Å cryo‐EM structure. We show that the major dodecameric cargo prApe1 exhibits a tendency to form higher‐order chain structures that are broken upon interaction with the receptor Atg19 in vitro. The stoichiometry of these cargo–receptor complexes is key to maintaining the size of the Cvt aggregate in vivo. Using correlative light and electron microscopy, we further visualize key stages of Cvt vesicle biogenesis. Our findings suggest that Atg19 interaction limits Ape1 aggregate size while serving as a vehicle for vacuolar delivery of tetrameric Ams1.