The rice foot rot pathogen Dickeya zeae alters the in-field plant microbiome

Studies on bacterial plant diseases have thus far been focused on the single bacterial species causing the disease, with very little attention given to the many other microorganisms present in the microbiome. This study intends to use pathobiome analysis of the rice foot rot disease, caused by Dickeya zeae, as a case study to investigate the effects of this bacterial pathogen to the total resident microbiome and to highlight possible interactions between the pathogen and the members of the community involved in the disease process. The microbiome of asymptomatic and the pathobiome of foot-rot symptomatic field-grown rice plants over two growing periods and belonging to two rice cultivars were determined via 16S rRNA gene amplicon sequencing. Results showed that the presence of D. zeae is associated with an alteration of the resident bacterial community in terms of species composition, abundance and richness, leading to the formation of microbial consortia linked to the disease state. Several bacterial species were significantly co-presented with the pathogen in the two growing periods suggesting that they could be involved in the disease process. Besides, culture-dependent isolation and in planta inoculation studies of a bacterial member of the pathobiome, identified as positive correlated with the pathogen in our in silico analysis, indicated that it benefits from the presence of D. zeae. A similar microbiome/pathobiome experiment was also performed in a symptomatically different rice disease evidencing that not all plant diseases have the same consequence/relationship with the plant microbiome. This study moves away from a pathogen-focused stance and goes towards a more ecological perception considering the effect of the entire microbial community which could be involved in the pathogenesis, persistence, transmission and evolution of plant pathogens.     

Different specific activities of the monomeric and oligomeric forms of plasmid DNA in transformation of B. subtilis and E. coli.

Summary (1) The low residual transforming activity in preparations of monomeric, supercoiled, circular (CCC) forms of the plasmids pC194 and pHV14 could be attributed to the presence in such isolates of a small number of contaminating multimeric molecules. (2) E. coli derived preparations of pHV14, an in vitro recombinant plasmid capable of replication in both E. coli and B. subtilis, contain oligomeric forms of plasmid DNA in addition to the prevalent monomeric CCC form. The specific transforming activity of pHV14 DNA for E. coli is independent of the degree of oligomerization, whereas in transformation of B. subtilis the specific activity of the purified monomeric CCC molecules is at least four orders of magnitude less than that of the unfractionated preparation. (3) Oligomerization of linearized pHV14 DNA by T4 ligase results in a substantial increase of specific transforming activity when assayed with B. subtilis and causes a decrease when used to transform E. coli.     

Glycosphingolipid metabolic reprogramming drives neural differentiation

Neural development is accomplished by differentiation events leading to metabolic reprogramming. Glycosphingolipid metabolism is reprogrammed during neural development with a switch from globo‐ to ganglio‐series glycosphingolipid production. Failure to execute this glycosphingolipid switch leads to neurodevelopmental disorders in humans, indicating that glycosphingolipids are key players in this process. Nevertheless, both the molecular mechanisms that control the glycosphingolipid switch and its function in neurodevelopment are poorly understood. Here, we describe a self‐contained circuit that controls glycosphingolipid reprogramming and neural differentiation. We find that globo‐series glycosphingolipids repress the epigenetic regulator of neuronal gene expression AUTS2. AUTS2 in turn binds and activates the promoter of the first and rate‐limiting ganglioside‐producing enzyme GM3 synthase, thus fostering the synthesis of gangliosides. By this mechanism, the globo–AUTS2 axis controls glycosphingolipid reprogramming and neural gene expression during neural differentiation, which involves this circuit in neurodevelopment and its defects in neuropathology.     

Serological response to chlamydial infection in sheep, studied by enzyme-linked immunosorbent assay and immunoblotting

Abstract Two enzyme-linked immunosorbent assays (ELISA) using highly purified elementary bodies (EB) of Chlamydia psittaci A/22 strain (ovine) or 6BC strain (psittacine) were set up for the detection of antichlamydial antibodies in sheep. No significant differences were observed between the two ELISAs, whereas these tests proved to be more sensitive than complement fixation test and showed a good correlation ( r = 0.75) with immunofluorescence assay. The periodate treatment of chlamydial antigens modified the results of serological responses studied by ELISA, depending on the sera. The average reduction of ELISA values by periodate was 28%, ranging between 5% and 65%. The immunoblot analysis of sheep sera showed high cross reactivity between the polypeptides of A/22 and 6BC strains. However, some differences were observed. The major outer membrane protein (MOMP) of 6BC strain was recognized at different molecular weight position (40 000 kDa) in comparison with the MOMP of A/22 strain (38 000 kDa). In addition, a clear band of 97 000 kDa was detected by all sheep sera tested with A/22 strain. This band was undetectable in the blots performed with 6BC strain.     

Smoking,health and ageing

On March 19, 2008 a Symposium on Pathophysiology of Ageing and Age-Related diseases was held in Palermo, Italy. Here, the lecture of V. Nicita-Mauro on Smoking, health and ageing is summarized. Smoking represents an important ageing accelerator, both directly by triggering an inflammatory responses, and indirectly by favoring the occurrence of several diseases where smoking is a recognized risk factor. Hence, non-smokers can delay the appearance of diseases and of ageing process, so attaining longevity.     

In vitro studies during long term oral administration of specific transfer factor

153 patients suffering from recurrent pathologies, i.e. viral infections (keratitis, keratouveitis, genital and labial herpes) uveitis, cystitis, and candidiasis were treated with in vitro produced transfer factor (TF) specific for HSV-1/2, CMV and Candida albicans. The cell-mediated immunity of seropositive patients to HSV-1/2 and/or CMV viruses was assessed using the leucocyte migration inhibition test (LMT) and lymphocyte stimulation test (LST) in presence of the corresponding antigens, and the frequency of positive tests before, during and after TF administration was studied. The data were stratified per type of test, antigen and the recipients’ pathology, and statistically evaluated. For the LMT, a total of 960 tests were carried out for each antigen dilution, 3 different antigen dilutions were used per test. 240/960 tests (25.4%) were found positive during non-treatment or treatment with unspecific TF, whereas 147/346 tests (42.5%) were found positive when the antigen corresponding to the specificity of the TF administered to the patient was used (P<0.001). When the data were stratified following pathology, a significant increased incidence of positive tests during specific treatment was also observed (0.0001<P<0.05). In the LST (1174 tests), a significant increase of thymidine uptake was observed in the absence of antigen (control cultures), during treatment with both specific and unspecific TF, but also in the presence of antigen and/or autologous serum during specific TF administration (P<0.0001). TF administration also significantly increased the soluble HLA class I antigens level in 40 patients studied to this effect.     

An upper Tuvalian (Triassic) platform-basin system in the Julian Alps: the start-up of the Dolomia Principale (Southern Alps,Italy)

Summary East of Cave del Predil (formerly Raibl), a platform-basin transition of the Dolomia Principale (Hauptdolomit) is spectacularly exposed at a seismic scale. Therefore, the eastern margin of the vast domain of the Dolomia Principale, facing the Slovenian Basin, is documented. Despite of strong dolomitization of the massive margin, some sedimentary structures and fossils have been recognized. Corals seem to be very rare and sponges to be absent, whereas serpulids and marine phreatic cements seem to have been the main components of the framework. Interior platform bedded dolomites lap off the massive margin. Clinoforms interfinger with upper Tuvalian basinal deposits (Carnitza Formation). This setting documents the start-up of the Dolomia Principale during late Tuvalian time. Moreover, this margin of the Dolomia Principale is the more ancient so far pointed out. It testifies to the recovery of a rimmed platform after the late Julian-early Tuvalian crisis.