Constraining Jupiter's internal flows using Juno magnetic and gravity measurements

Deciphering the flow below the cloud-level of Jupiter remains a critical milestone in understanding Jupiter's internal structure and dynamics. The expected high-precision Juno measurements of both the gravity field and the magnetic field might help to reach this goal. Here we propose a method that combines both fields to constrain the depth-dependent flow field inside Jupiter. This method is based on a mean-field electrodynamic balance that relates the flow field to the anomalous magnetic field, and geostrophic balance that relates the flow field to the anomalous gravity field. We find that the flow field has two distinct regions of influence: an upper region in which the flow affects mostly the gravity field and a lower region in which the flow affects mostly the magnetic field. An optimization procedure allows to reach a unified flow structure that is consistent with both the gravity and the magnetic fields

Helicity Spectra and Dissipation

Both dissipation of helicity and it spectrum we are study on the basis of asymptotic model. Introduction into model dependence of angle between turbulent components vorticity and velocity on the governing parameters leads to the spectra of helicity observed experimentally and obtained by DNS model computations by various authors. At the same time, it settles the problem of helicity dissipation divergence with growing Reynolds number

BIOCHEMICAL FUNCTIONAL CHARACTERIZATION AND MOLECULAR BIOLOGY OF PLANT INHIBITOR PROTEINS ACTING AGAINST GLYCOSIDE HYDROLASE

Plant cell walls are composed mostly of polysaccharides and it consist of three layers (the primary cell wall, the secondary cell wall and the middle lamella) that are made up of different percentage of cellulose, pectins and hemicelluloses. These latter are composed of a linear backbone made up of (1,4)-\u3b2-D-glycans with an equatorial configuration. Based on type of glycans forming the backbone it is possible to distinguish: mannans contain \u3b2-(1,4)-linked mannose; in xyloglucan \u3b2-1,4 glucans can be substituted with a diverse array of glycosyl and nonglycosyl residues and xylans are composed by \u3b2-(1,4)-linked xylose residues. The seeds of many legumes are known to accumulate galactomannan in their endospermic cell walls. In many dicots xyloglucans constitute the major hemicellulose of growing cell walls, comprising ~20% of the dry mass of primary cell walls. Grasses - but not monocots in general - have a reduced xyloglucan content. Cell wall polysaccharide biogenesis includes polymer synthesis, secretion, assembly, and rearrangement during development. All of these modification demands the reversible \u2018loosening\u2019 of the cellulose\u2013 hemicellulose\u2013pectin network. Glycoside hydrolase (GH) enzymes located in the wall or in the plasma membrane play a crucial role in the degradation of different cell wall polysaccharides. On the other hand, pathogenic microorganisms secrete glycoside hydrolase to penetrate plant cell walls. As a response, plants produce glycoside hydrolase inhibitor proteins (GHIPs). Xyloglucan- specific endo-\u3b2-1,4-glucanase inhibitor proteins-like (XEGIPs-like) are typical of dicots, they inhibit the hydrolytic activity of a xyloglucan-specific \u3b2-1,4-endoglucanase isolated from GH12 family. XEGIPs-like have been found widespread in dicots: they were detected in the medium of cultured tomato cells, purified from carrot callus, isolated from the nectar of ornamental tobacco, when overexpressed they were capable of protecting potato from disease caused by endo-\u3b2-1,4- glucanase GH12 from Phytophthora infestans, enhanced in apple in response to infection of Botryosphaeria dothidea, they have distinct roles in defence mechanisms in Humulus lupus. In cereals three types of GHIPs occur in a fairly coordinated fashion throughout grain development and germination: Triticum aestivum L. endoxylanase inhibitors (TAXIs-like), xylanase inhibitor proteins (XIPs-like), thaumatin-like xylanase inhibitors (TLXIs-like). The accumulation of GHIPs during the early stages of germination is consistent with the phenomenon of germination-based resistance and their highest concentrations occur in the aleuronic layer. The apoplastic localization of GHIPs in cereals may be favourable for their action as inhibitors of microbial xylanases GH10 and/or GH11 from Aspergillus niger, Bacillus subtilis and Hypocrea jecorina intruding the host plant. GHIPs homologous are also present in legume (LACGs-like): \u3b3-conglutin is largely expressed and accumulated in Lupinus spp. and Bg7S in Glycine spp. GHIPs have common structural features. In particular, the alignment of the primary structurer showed that the position of the 12 cysteines is fully conserved, so various GHIPs have similar three- dimensional structures. Cys10-Cys11 is located at the C-terminal region of the proteins, the sequence amongst them is called \u201cinhibition loop 1\u201d and a conserved arginine, in XEGIPs-like, or leucine, in TAXI-I, is involved in the bond GH12 or GH11, respectively. In the LAGCs-like it\u2019s also present the loop, but a deletion of about five amino acids involve this region, otherwise highly conserved. The superimposition of TAXI-I 3D structure (PDB accession number: 1T6E) and EDGP 3D structure (PDB accession number: 3VLA) with \u3b3-conglutin 3D structure (PDB accession number: 4PPH) confirm the structural difference of the loop responsible for the interaction with the enzyme as a consequence of the five amino acid long deletion. This may be the cause of an unfavourable local spatial conformation of the protein for the correct interaction with the enzyme. The disulphide bridge Cys9-Cys12 define another region called \u201cinhibition loop 2\u201d where a conserved arginine, in XEGIPs-like, or histidine, in TAXIs-like and LACGs-like, is involved in the bond with a specific GH. The sequence of the IL2 loop of \u3b3-conglutin is more similar to the sequence of the IL2 loop of TAXI-I, rather than to the one of XEGIPs. In particular, a His residue, considered a key amino acid for the inhibitory activity of TAXI-I is also present in \u3b3-conglutin sequence, but not in XEGIPs. \u3b3-conglutin was expressed in Pichia pastoris. Unexpectedly, this recombinant \u3b3-conglutin (r\u3b3c) was able to inhibit a GH11 enzyme, but not GH12. In lupin, \u3b3-conglutin is naturally cleaved in two subunits, whereas in P. pastoris it is not. Most likely, the proteolytic processing influences the structural conformation of \u3b3-conglutin and small local rearrangements may be the cause of the observed activity. Also a set of \u3b3-conglutin mutants was designed upon TAXIs-like and XEGIPs-like sequences and expressed in Pichia pastoris. The mutants were able to modulate the inhibition capacity. The enzymatic assays and the bioinformatics analysis confirmed that the presence of IL1 is not strictly required to manifest inhibition, even if the specifically inserted amino acid stretches enhanced the activity. On the other hand, histidine in IL2 is confirmed to be necessary and sufficient to manifest the inhibitory competence of r\u3b3c. The LACGs-like among GHIPs remains the less characterized. For this reason, we undertook experiments aimed to study the inhibitory specificity of wild type \u3b3-conglutin. Inhibitory capacity was tested against under different condition using selected GH2 and GH5 members. GH11 and GH12 were not tested since previous results evidenced no capacity. In Arabidopsis thaliana, which is a small flowering plant widely used as a model organism in plant biology, we have found five genes coding for GHIPs belonging to each of three aforementioned groups. At1g03220 and At1g03230 are closer related to XEGIPs-like proteins: the cysteines pathway is totally conserved, they show arginine in the inhibition loop 1 and inhibition loop 2, which interact with glycoside hydrolases family 12, and along the sequences there are some potential glycosylation sites. At5g19110 is the unique putative proteins that shows leucine and histidine in the inhibition loop 1 and inhibition loop 2, respectively, the same region used by TAXIs-like to interact with glycoside hydrolases family GH11. At5g19100 and At5g19120 show the characteristic LACGs-like deletion at the IL1 and only in At5g19100 sequence at the IL2 we recover the histidine like both LACGs-like and TAXIs-like. We have studied the expression of these genes to deep into the biology of the plant response to pathogen attack. The results of this set of experiment contributed to unveil the role of each. The seeds were germinated in Petri dishes with MS medium and held in growth chambers with constant temperature of 21\ub0C, under long-day photoperiod, for different times (0-23-48-96-144 hours) and in different conditions simulating biotic stresses. Western-blot with antibody anti-C\u3b3 show the presence of a similar \u3b3-conglutin protein in A. thaliana seeds at 96h of germination in MS medium and then incubate in a chitosan (150 mg/L) solution for 3h. For the first time we show that proteolytic processing of LACGs-like occurs in organism other than legume. In parallel, total RNAs were extracted and RT-qPCR has been set up to quantify the relative expression levels of gene expression. The GHIPs homologues genes after 48, 96 and 144 hours of germination aren\u2019t expressed under basal condition. Seeds germinated for 96 hours and then exposed to incubation with aqueous solution or 150mg/l chitosan solution (mimic a biotic stress) shown an expression of gene, greater if the biotic stress was applied at seeds contaminated. In the seeds germinated in dishes that after 96 hours shown a spontaneous growth of Paenibacillus polymyxa, an endophytic bacterium exploited as biocontrolling agent. In this case the expression of all analysed genes increased. In another experimental set we tested the direct effect of GH2, GH5, GH11 treatment on A. thaliana seedling 7 days old. In this contest, it has been evaluated both the expression of the five selected genes and the effects on the enzymes due to plants exudates. By and large, this work describes new experimental findings that open new interesting scenarios to better understand some physiological aspects of the plant defence mechanisms, and provides insight of the structural basis of GHIPs inhibitory activity, specificity and repercussions on cellular responses to pathogens attacks

Cell Death and Reproductive Regression in Female Schistosoma mansoni

The vitellarium is a highly proliferative organ, producing cells which are incorporated along with a fertilized ovum into the schistosome egg. Vitellarial growth fails to occur in virgin female schistosomes in single sex (female-only) infections, and involution of this tissue, which is accompanied by physical shrinkage of the entire worm, occurs when mature females sexually regress upon removal from their male partners. We have found that upon removal from their hosts into tissue culture, female parasites regress whether they are mated or not, but that cessation of egg production and a decline in expression of the vitelline gene p14 is delayed by mating. We used BrdU labeling to investigate whether there was a loss of proliferation in the vittelarium that might account for regression and found that the proliferation rate declined equally in paired and singled females once placed into culture. However, TUNEL staining and Caspase 3 activity measurements indicate that the loss of vitrellarial cellularity associated with regression is associated with profound apoptotic vitelline cell death, which is not apparent in the vitellaria of paired females immediately ex vivo, and which develops in vitro regardless of whether males are present or not. Furthermore, primordial vitellaria in virgin females have a high frequency of apoptotic cells but are characterized by a proliferation rate that is indistinguishable from that in fully developed vitellaria in mature paired females. Taken together, our data suggest that the vitelline proliferation rate is independent of pairing status. In contrast, the survival of vitelline cells, and therefore the development of the vitellarium, is highly male-dependent. Both processes are negatively affected by removal from the host regardless of whether male worms are present or not, and are unsustainable using standard tissue culture approaches

Constraining Jupiter's internal flows using Juno magnetic and gravity measurements

Deciphering the flow below the cloud-level of Jupiter remains a critical milestone in understanding Jupiter's internal structure and dynamics. The expected high-precision Juno measurements of both the gravity field and the magnetic field might help to reach this goal. Here we propose a method that combines both fields to constrain the depth-dependent flow field inside Jupiter. This method is based on a mean-field electrodynamic balance that relates the flow field to the anomalous magnetic field, and geostrophic balance that relates the flow field to the anomalous gravity field. We find that the flow field has two distinct regions of influence: an upper region in which the flow affects mostly the gravity field and a lower region in which the flow affects mostly the magnetic field. An optimization procedure allows to reach a unified flow structure that is consistent with both the gravity and the magnetic fields

The inverse cascade and nonlinear alpha-effect in simulations of isotropic helical hydromagnetic turbulence

A numerical model of isotropic homogeneous turbulence with helical forcing is investigated. The resulting flow, which is essentially the prototype of the alpha^2 dynamo of mean-field dynamo theory, produces strong dynamo action with an additional large scale field on the scale of the box (at wavenumber k=1; forcing is at k=5). This large scale field is nearly force-free and exceeds the equipartition value. As the magnetic Reynolds number R_m increases, the saturation field strength and the growth rate of the dynamo increase. However, the time it takes to built up the large scale field from equipartition to its final super-equipartition value increases with magnetic Reynolds number. The large scale field generation can be identified as being due to nonlocal interactions originating from the forcing scale, which is characteristic of the alpha-effect. Both alpha and turbulent magnetic diffusivity eta_t are determined simultaneously using numerical experiments where the mean-field is modified artificially. Both quantities are quenched in a R_m-dependent fashion. The evolution of the energy of the mean field matches that predicted by an alpha^2 dynamo model with similar alpha and eta_t quenchings. For this model an analytic solution is given which matches the results of the simulations. The simulations are numerically robust in that the shape of the spectrum at large scales is unchanged when changing the resolution from 30^3 to 120^3 meshpoints, or when increasing the magnetic Prandtl number (viscosity/magnetic diffusivity) from 1 to 100. Increasing the forcing wavenumber to 30 (i.e. increasing the scale separation) makes the inverse cascade effect more pronounced, although it remains otherwise qualitatively unchanged.Comment: 21 pages, 26 figures, ApJ (accepted

Cocirculation of Hajj and non-Hajj strains among serogroup W meningococci in Italy, 2000 to 2016

In Italy, B and C are the predominant serogroups among meningococci causing invasive diseases. Nevertheless, in the period from 2013 to 2016, an increase in serogroup W Neisseria meningitidis (MenW) was observed. This study intends to define the main characteristics of 63 MenW isolates responsible of invasive meningococcal disease (IMD) in Italy from 2000 to 2016. We performed whole genome sequencing on bacterial isolates or single gene sequencing on culturenegative samples to evaluate molecular heterogeneity. Our main finding was the cocirculation of the Hajj and the South American sublineages belonging to MenW/ clonal complex (cc)11, which gradually surpassed the MenW/cc22 in Italy. All MenW/cc11 isolates were fully susceptible to cefotaxime, ceftriaxone, ciprofloxacin, penicillin G and rifampicin. We identified the fulllength NadA protein variant 2/3, present in all the MenW/cc11. We also identified the fHbp variant 1, which we found exclusively in the MenW/cc11/Hajj sublineage. Concern about the epidemic potential of MenW/cc11 has increased worldwide since the year 2000. Continued surveillance, supported by genomic characterisation, allows high-resolution tracking of pathogen dissemination and the detection of epidemicassociated strains

On the Structure of the Magnetic Field in a Kinematic ABC Flow Dynamo

The kinematic induction equation of MHD is solved numerically in the case of the normal ``111'' ABC flow using a general staggered mesh method. Careful 3-D visualizations of the topology of the magnetic field reveal that previous conclusions about the modes of operation of this type of kinematic dynamo must be revised. The two known windows of dynamo action at low and high magnetic Reynolds number, correspond to two distinct modes, both relying crucially on the replenishing of the magnetic field near a discontinuity at the beta-type stagnation points in the flow. One of these modes display double magnetic structures that were previously found only to obscure the physics of the dynamo: They turn out, however, to play an important part in the process of amplifying the magnetic field. Invariant properties of the mode in the second magnetic Reynolds number window support the case for the normal ABC flow as a fast dynamo.Comment: Associated webpage, see http://www.astro.su.se/~dorch/dynamo

Lagrangian analysis of alignment dynamics for isentropic compressible magnetohydrodynamics

After a review of the isentropic compressible magnetohydrodynamics (ICMHD) equations, a quaternionic framework for studying the alignment dynamics of a general fluid flow is explained and applied to the ICMHD equations.Comment: 12 pages, 2 figures, submitted to a Focus Issue of New Journal of Physics on "Magnetohydrodynamics and the Dynamo Problem" J-F Pinton, A Pouquet, E Dormy and S Cowley, editor

Cysteine-containing peptides are produced by sequential clipping, but not released, from lupin 11S storage globulin during early germination

The digestion of the seed storage proteins is a finely regulated process operated by several proteases whose action is influenced by the exposure of specific regions, which became progressively available upon their action. We focused our study on the initial stages of germination, where more subtle modifications to the storage proteins are expected. Small-size peptides containing cysteine residues and other possible metalbinding regions are de facto produced but are not released from the \u201cparental\u201d protein since they remain bound trough disulphide bridges. The meaning of these findings is discussed