Lytic to temperate switching of viral communities.

Microbial viruses can control host abundances via density-dependent lytic predator-prey dynamics. Less clear is how temperate viruses, which coexist and replicate with their host, influence microbial communities. Here we show that virus-like particles are relatively less abundant at high host densities. This suggests suppressed lysis where established models predict lytic dynamics are favoured. Meta-analysis of published viral and microbial densities showed that this trend was widespread in diverse ecosystems ranging from soil to freshwater to human lungs. Experimental manipulations showed viral densities more consistent with temperate than lytic life cycles at increasing microbial abundance. An analysis of 24 coral reef viromes showed a relative increase in the abundance of hallmark genes encoded by temperate viruses with increased microbial abundance. Based on these four lines of evidence, we propose the Piggyback-the-Winner model wherein temperate dynamics become increasingly important in ecosystems with high microbial densities; thus 'more microbes, fewer viruses'.

IL-33 and IgE stimulate mast cell production of IL-2 and regulatory T cell expansion in allergic dermatitis.

BACKGROUND: We have previously shown that mast cells (MCs) suppress chronic allergic dermatitis in mice. The underlying mechanism involves MC-derived IL-2, which supports regulatory T cell (Treg) response at the site of inflammation. However, it is not clear what are the factors that drive MCs to produce IL-2. OBJECTIVE: To understand the mechanisms that lead to IL-2 production from MCs in chronic allergic dermatitis. METHODS: Isolated murine bone marrow-derived MCs (BMMCs) were incubated with various stimulators, and IL-2 production was assessed by RT-PCR and ELISA. The response of signalling pathways was evaluated by MAPK inhibitors and Western blot analysis. The effect of MC-IL-2 on Tregs was studied by incubation of splenic T cells with conditioned media obtained from activated BMMCs. Dermatitis was elicited by repeated exposures of mouse ears to oxazolone. MCs in mouse and human skin samples were evaluated by immunostaining. RESULTS: BMMCs released IL-2 in response to IL-33, and IL-2 production was further enhanced by concomitant FcεRI activation. The effect of IL-33 was mediated by activation of the MAPK family members. IL-2 in conditioned media from IL-33 and IgE-stimulated BMMCs led to considerable expansion of Tregs in vitro. IL-33 levels were elevated in oxazolone-challenged ears along with increased numbers of IL-2-expressing MCs. Human skin with chronic inflammation also contained IL-2-expressing MCs that colocalized with IL-33 staining in the dermis. CONCLUSIONS: IL-33, in collaboration with IgE, is critical for MC-IL-2 production in allergic skin disease, thus leading to Treg stimulation and suppression of allergic dermatitis.

First Report of Bacterial Wilt on Chrysanthemum Caused by Dickeya chrysanthemi (syn. Erwinia chrysanthemi) in Hungary.

Chrysanthemum (Chrysanthemum spp.) is a popular potted and cut plant ornamental in Hungary. In September 2012, chrysanthemum plants (Chrysanthemum morifolium Ramat. cv. Palisade) showing wilt symptoms were collected from different greenhouses in the cities of Budakalász and Pilis near Budapest. Affected plants had dark brown to black lesions on the leaves and stems. Spots on the leaves were first water soaked and then became necrotic, and the plants wilted. According to the growers, disease symptoms developed rapidly, resulting in losses of nearly 100%. The disease caused a loss of ~€2,000 for the growers in cities of Budakalász and Pilis in Hungary. Losses for growers and consumers could have reached half a million euros. Ten samples were used for disease diagnosis and bacteria were isolated according to the method of Schaad et al. (3). Briefly, diseased leaf and stem tissues were macerated and streaked onto King's medium B (KB). Colonies on KB were white and non-fluorescent. All 10 strains grew at 26°C, were gram negative, and induced a hypersensitive response on tobacco (Nicotiana tabacum L. 'White Burley') leaves (1). Biochemical tests were also used for identification, and the results of API 20E (Biomérieux, Marcy l'Etoile, France), demonstrated that the bacterium belonged to the Enterobacteriaceae. The strain was positive for ß-galactosidase and citrate utilization, acetoin and indole production, gelatinase, and utilization of glucose, mannitol, saccharose, melibiose, and arabinose. For molecular identification of the pathogen, the 16S rDNA gene was amplified from strain DCBK-1H with a general primer pair (63f/1389r) (2). The PCR products were cloned into a pGEM T-Easy plasmid vector (Promega, Madison, WI) and transformed into Escherichia coli DH5α cells. A recombinant plasmid (2A2.5) was sequenced using the M13 forward and reverse primers. The sequence was deposited in NCBI GenBank (Accession No. HF913430) and showed 99 to 100% sequence identity with a number of Dickeya chrysanthemi strains found in the database, including type strain HM590189, GQ293897, GQ293898 with 99% similarity and 100% identity with sequence FM946179. On the basis of the symptoms, colony morphology, biochemical tests, and 16S rDNA sequence homology, the pathogen was identified as D. chrysanthemi. Pathogenicity was tested by inoculating the recovered strains onto three 1-month-old, healthy potted chrysanthemum cuttings (C. morifolium cv. Palisade). Four leaves and stem each of three 'Palisade' cultivars were inoculated by injecting ~10 µl of a bacteria suspension containing 107 CFU/ml into each leaf and stem. As a negative control, one plant was inoculated with water in each of four leaves and stem. Plants were enclosed in plastic bags and incubated in a greenhouse under 80% shade at 26°C day and 17°C night temperatures. Within 24 h, water-soaked spots appeared on inoculated leaves and the plants were wilted. The water control appeared normal. D. chrysanthemi was re-isolated and identified as described above; thus, Koch's postulates were fulfilled. To our knowledge, this is the first report of bacterial wilt caused by D. chrysanthemi on chrysanthemum in Hungary. References: (1) Z. Klement. Nature 199:299, 1963. (2) A. M. Osborn et al. Environ. Microbiol. 2:39, 2000. (3) N. W. Schaad et al. Erwinia soft rot group. Page 56 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. N. W. Schaad et al., eds. American Phytopathological Society, St. Paul, MN, 2001.

First Report of Natural Infection of Pea (Pisum sativum) by Tomato spotted wilt virus in Hungary.

In June of 2009, stem vascular necrosis, interveinal necrosis of upper leaves, wilting of flowers, and necrotic spots on the pods were observed on garden pea (Pisum sativum L. 'Rajnai törpe') in northeast Hungary. A mechanical transmissible plant virus designated Ps091 was isolated from leaves of severely affected plants. Pathological investigations demonstrated that Ps091 had a host range very similar to that of Tomato spotted wilt virus (TSWV). It caused necrotic local lesions on Chenopodium spp. and induced systemic yellowing and necrosis on the upper leaves of Nicotiana benthamiana, N. clevelandii, and N. glutinosa by mechanical inoculation. Typical symptoms of TSWV infection appeared on the top leaves of pepper (Capsicum annuum L. 'Albaregia') and tomato (Solanum lycopersicum 'Kecskeméti 3') inoculated with Ps091. For molecular identification, total nucleic acids were extracted from Ps091-infected tobacco with a standard phenol-chloroform extraction method (2), and reverse transcription-PCR was conducted with TSWV N-gene specific, own designed primers (TSWV-S for: 5'-CCCAGCATTATGGCAAGCC-3', TSWV-S rev: 5'-TGATCTGGTCGAGGTTTTCCGCTAGCCC-3'). A tobacco plant infected with a reference pepper isolate, TSWV-Ca1 (1), and a healthy tobacco plant served as positive and negative controls, respectively. An approximately 300-bp DNA fragment was amplified from tobacco infected with Ps091 and TSWV-Ca1. The Ps091 amplicon was cloned, sequenced in both directions, and the sequence was deposited in GenBank (Accession No. HQ615692). Blast search analysis showed that TSWV-Ps091 had the highest identity (99%) with TSWV-P170RB strain (GenBank Accession No. DQ431238) in the cognate region. Since the latter isolate is a resistance breaking (RB) strain on pepper, pathogenicity of Ps091 on TSWV resistant pepper and tomato lines was studied. Mechanically inoculated pepper (C. annuum × C. chinense TSR F4 line) and tomato (S. lycopersicum 'Stevens') genotypes carrying the Tsw and Sw5 resistance genes, respectively, reacted with necrotic local lesions, but no systemic infections were detected by applying bioassays to N. clevelandii. These results demonstrate that Ps091 does not belong to the RB strains of TSWV. Back inoculations to pea ('Rajnai törpe') resulted in necrotic local spots as well as systemic stem and top necrosis, proving the causal relationship between TSWV-Ps091 and the pea disease observed in the field. Although TSWV has been known to cause epidemy in solanaceous crops and tobacco, to our knowledge, this is the first report of its natural occurrence on a legume plant, particularly on pea in Hungary. Because of the extreme severity of the disease caused on pea and high infection pressure, TSWV is a new threat to pea production in this country, where pea is a very important crop. References: (1) P. Salamon et al. Page 23 in: Plant Protection Days. Budapest, February, 2010. (2) J. L. White and J. M. Kaper. J. Virol. Methods 23:83, 1989.

Tensile forces and shape entropy explain observed crista structure in mitochondria.

We present a model from which the observed morphology of the inner mitochondrial membrane can be inferred as minimizing the system's free energy. In addition to the usual energetic terms for bending, surface area, and pressure difference, our free energy includes terms for tension that we hypothesize to be exerted by proteins and for an entropic contribution due to many dimensions worth of shapes available at a given energy. We also present measurements of the structural features of mitochondria in HeLa cells and mouse embryonic fibroblasts using three-dimensional electron tomography. Such tomograms reveal that the inner membrane self-assembles into a complex structure that contains both tubular and flat lamellar crista components. This structure, which contains one matrix compartment, is believed to be essential to the proper functioning of mitochondria as the powerhouse of the cell. Interpreting the measurements in terms of the model, we find that tensile forces of ∼20 pN would stabilize a stress-induced coexistence of tubular and flat lamellar cristae phases. The model also predicts a pressure difference of -0.036 ± 0.004 atm (pressure higher in the matrix) and a surface tension equal to 0.09 ± 0.04 pN/nm.

Development of a virus induced gene silencing vector from a legumes infecting tobamovirus.

Medicago truncatula, the model plant of legumes, is well characterized, but there is only a little knowledge about it as a viral host. Viral vectors can be used for expressing foreign genes or for virus-induced gene silencing (VIGS), what is a fast and powerful tool to determine gene functions in plants. Viral vectors effective on Nicotiana benthamiana have been constructed from a number of viruses, however, only few of them were effective in other plants. A Tobamovirus, Sunnhemp mosaic virus (SHMV) systemically infects Medicago truncatula without causing severe symptoms. To set up a viral vector for Medicago truncatula, we prepared an infectious cDNA clone of SHMV. We constructed two VIGS vectors differing in the promoter element to drive foreign gene expression. The vectors were effective both in the expression and in the silencing of a transgene Green Fluorescent Protein (GFP) and in silencing of an endogenous gene Phytoene desaturase (PDS) on N. benthamiana. Still only one of the vectors was able to successfully silence the endogenous Chlorata 42 gene in M. truncatula.

Modeling tubular shapes in the inner mitochondrial membrane.

The inner mitochondrial membrane has been shown to have a novel structure that contains tubular components whose radii are of the order of 10 nm as well as comparatively flat regions. The structural organization of mitochondria is important for understanding their functionality. We present a model that can account, thermodynamically, for the observed size of the tubules. The model contains two lipid constituents with different shapes. They are allowed to distribute in such a way that the composition differs on the two sides of the tubular membrane. Our calculations make two predictions: (1) there is a pressure difference of 0.2 atmospheres across the inner membrane as a necessary consequence of the experimentally observed tubule radius of 10 nm, and (2) migration of differently shaped lipids causes concentration variations of the order of 7% between the two sides of the tubular membrane.

Occurrence of Colombian datura virus in Brugmansia hybrids, Physalis peruviana L. and Solanum muricatum Ait. in Hungary.

Colombian datura virus (CDV) has been found to infect angel trumpets (Brugmansia spp.) frequently and cape gooseberry (Physalis peruviana) and pepino (Solanum muricatum) sporadically in Hungary. A CDV BRG/H isolate was characterized. It had flexuous thread-like virions of about 750 x 12 nm in size. Host range and symptomathological studies revealed its great similarity to authentic CDV isolates. Nicotiana tabacum cultivars and lines resistant to Potato virus Y (PVYN) either genically or transgenically proved highly susceptible to the BRG/H isolate. Tomato (L. esculentum cvs.) was systemically susceptible to this isolate, but some lines of Lycopersicon hirsutum and L. peruvianum turned out to be resistant. Browallia demissa, Ipomoea purpurea, N. megalosiphon and S. scabrum were demonstrated as new experimental hosts of CDV. The BRG/ H isolate proved to be transmissible by the aphid Myzus persicae Sulz. in a non-persistent manner. Potyvirus-specific coat protein (CP) gene sequences of about 1700 bp from angel trumpet, cape gooseberry and pepino plants were amplified by RT-PCR. The cloned BRG/H CP gene showed a 99.12-99.31% identity with other CDV isolates. CDV has been found for the first time to infect naturally cape gooseberry and pepino. Since the botanical genus name of original hosts of CDV has changed from Datura to Brugmansia, we propose to change the virus name from CDV to Angel trumpet mosaic virus (ATMV).

Efficient pathogen-derived resistance induced by integrated potato virus Y coat protein gene in tobacco.

The coat protein (CP) gene from potato virus Y (Hungarian isolate, PVY-H) was engineered into Agrobacterium tumefaciens binary vector for expression in different tobacco lines. Three different Nicotiana tabacum breeding lines were transformed and the integration of the CP gene was confirmed by PCR technique using genomic DNA preparations. The transcription and expression of the integrated CP gene was detected by Northern and Western blots. Pathogen-derived resistance was demonstrated by inoculation of the R1 progeny of the transformed lines with purified PVY-H. The efficiency of protection varied between different transgenic plants ranging from almost complete to no protection. Five CP expressing tobacco lines were resistant to challenge infection with PVY-H as indicated by attenuation or absence of symptom development associated with reduction or lack of detectable virus accumulation. Data from Western blots showed that there is no correlation between the level of the expressed CP and the extent of protection. This suggests that the mechanism of the observed resistance is independent of the level of CP accumulation in the transgenic tobacco plants.

The complete nucleotide sequence and synthesis of infectious RNA of genomic and defective interfering RNAs of TBSV-P.

The complete nucleotide sequences of the genome of the pepper isolate of tomato bushy stunt Tombusvirus (TBSV-P), and its defective interfering (DI) RNAs were determined. The genome of TBSV-P is a linear single-stranded monopartite RNA molecule of positive polarity, 4776 nucleotides long and has an organisation identical to that reported for other tombusviruses. In vitro transcripts of the genome were highly infectious, and it could support replication of the DI RNAs associated with the wild type virus. Two DI RNAs were found in the infected leaves of Nicotiana clevelandii, whose sequences were completely derived from the genomic RNA. The longest DI RNA (DI-5) has 550 nucleotides (nt), while the shorter DI RNA (DI-4) composed of 463 nt, both of them were formed by essentially the same genomic sequence blocks. Since host specificity of TBSV-P and other tombusviruses with available infectious cDNA clones is different, it is feasible to carry out gene exchange studies to determine viral host specificity factors for tombusviruses.

Ulnar variance in Kienböck's disease.

The distal extent of the radius and ulna (ulnar variance) was compared on roentgenograms of normal wrists in randomly selected black and white patients and of fifteen affected wrists in patients with Kienbock's disease. The results establish a statistically significant association between negative ulnar variance and Kienbock's disease. Blacks have more positive ulnar variance and the disease is less likely to develop in them than in whites.

A controlled study of the indications for and the results of femoral osteotomy in Perthes' disease.

We have considered the reasons for securing containment of the femoral head in Perthes' disease and have reviewed briefly the methods used. The present investigation describes the outcome in a controlled series of forty-eight hips treated by containment by femoral varus-rotation osteotomy in selected patients. In assessing the results we have emphasised that controls are essential, and for this purpose we have used two comparable groups, one untreated and the other treated by methods other than containment. The same factors were considered in assessment--namely age, duration, group, and the presence or absence of "at risk" signs. The results were graded similarly as good, fair and poor in all groups. We have concluded that containment by femoral osteotomy is the treatment of choice in patients with "at risk" signs provided that severe deformity has not already occurred. There is no evidence that treatment of any kind favourably influences the course of the disorder in the remainder. Although this is predominantly a radiological study some clinical features are discussed.

Femoral anteversion. A clinical assessment of idiopathic intoeing gait in children.

Hip rotation in extension and flexion was studied in 23 patients with idiopathic intoeing gait. In extension all the hips had markedly increased medial rotation and limited lateral rotation, fulfilling the criteria of excessive femoral anteversion. In flexion, however, rotation varied widely; in one group of patients medial rotation remained greater than lateral, but in the second group lateral rotation was equal to or greater than medial. CT scans showed that the hips in the first group were significantly more anteverted than those in the second. Clearly measurement of hip rotation in extension alone does not provide a dependable indication of femoral anteversion in children with intoeing gait; rotation in flexion also needs to be measured.

[Comparative study to assess the efficacy and adverse effects of amlodipine and nifedipine retard in patients with stable exertional angina and hypertension]. / Badania porównawcze skutecznosci i dzialania niepozadanego amlodypiny i nifedypiny retard u chorych na dlawice piersiowa stabilna z wspólistniejacym nadcisnieniem tetniczym.

The purpose of the study was to compare the antianginal and hypotensive efficacy and tolerability of 8 weeks of treatment with amlodipine taken once daily and nifedipine taken twice daily in patients with stable exertional angina pectoris and mild-to-moderate hypertension. Following a 2-week placebo run-in-period 13 patients were randomized to receive amlodipine (5 to 10 mg once daily) and 8 patients to receive nifedipine (20 or 40 mg twice daily) in an 8-week treatment phase. Antianginal efficacy was assessed with angina diares, investigators, and patients global evaluations and with treadmill exercise test during placebo run-in-period and after 8 weeks of the therapy. Amlodipine significantly reduced both weekly anginal attacks and consumption of glyceryl trinitrate tablets. This effect was more pronounced compared to efficacy of nifedipine. Exercise tolerance was also improved more markedly after amlodipine than after nifedipine treatment. Amlodipine treatment resulted in significant increase in total exercise time, increase the exercise time to angina onset, increase time to ST segment depression, decrease in ST segment depression, decrease in total duration of ST segment depression and decrease in duration of pain. In patients treated with nifedipine only favourable effect was significant decrease in total duration of ST segment depression, without significant changes of other examined parameters. Both drugs decreased blood pressure with no significant change in heart rate. No serious adverse events occurred in any patients during therapy with amlodipine as well as with nifedipine. The results of the study demonstrate that amlodipine has markedly better anti-anginal efficacy than nifedipine with respect to the most of the parameters examined. However both drugs showed comparable antihypertensive action and both were well tolerated by angina patients. The good anti-anginal and hypotensive efficacy and safety of amiodipine with once daily dosage regimen makes this drug an excellent choice of treatment for hypertensive patients with severe coronary artery disease.

Optimal control of a collection of parametric oscillators.

The problem of effectively adiabatic control of a collection of classical harmonic oscillators sharing the same time-dependent frequency is analyzed. The phase differences between the oscillators remain fixed during the process. This fact leads us to adopt the coordinates: energy, Lagrangian, and correlation, which have proved useful in a quantum description and which have the advantage of treating both the classical and quantum problem in one unified framework. A representation theorem showing that two classical oscillators can represent an arbitrary collection of classical or quantum oscillators is proved. An invariant, the Casimir companion, consisting of a combination of our coordinates, is the key to determining the minimum reachable energy. We present a condition for two states to be connectable using one-jump controls and enumerate all possible switchings for one-jump effectively adiabatic controls connecting any initial state to any reachable final state. Examples are discussed. One important consequence is that an initially microcanonical ensemble of oscillators will be transformed into another microcanonical ensemble by effectively adiabatic control. Likewise, a canonical ensemble becomes another canonical ensemble.

Dielectric technique to measure the twist elastic constant of liquid crystals: the case of a bent-core material.

The effect of director pretilt on the twist magnetic Fréedericksz transition of nematics was investigated in a planar cell. The director configuration was calculated as a function of magnetic inductance. The dielectric and optical response of the nematic liquid crystal was numerically modeled. A dielectric measurement method for determining the elastic constant K_{22} is presented. The influence of the conditions for the Mauguin effect is discussed. The theoretical predictions were confirmed by our experiments. Experimental data for all elastic constants of a bent-core nematic material are presented and discussed.

Elastic constants and orientational viscosities of a bent-core nematic liquid crystal.

Using a combination of dynamic light scattering and Freedericksz transitions induced in applied magnetic and electric fields, we have determined the absolute magnitudes of the Frank elastic constants and effective orientational viscosities of the bent-core nematic liquid crystal, 4-chloro-1,3-phenylene bis 4-[4'-(9-decenyloxy)benzoyloxy] benzoate. At a fixed temperature 2 °C below the isotropic-nematic transition, we find K11 = 3.1 x 10⁻¹² N, K22 = 0.31 x 10⁻¹² N, K33 = 0.88 x 10⁻¹² N, η{splay}=1.1 Pa s, η{twist}=0.37 Pa s, and η{bend}=1.2 Pa s. The unusual anisotropies of these parameters are discussed in terms of short-range, smectic-C-like correlations among molecules in the nematic phase.