Microbial colonization and succession on the faucial mucosa in newborn infants rooming in with their mothers in a maternity hospital]

The formation of microflora on the laryngeal mucosa in newborn infants during the first 5 days of their life was studied in one of the maternity hospitals of Moscow. In this work modern methods of the isolation and identification of aerobic and anaerobic microorganisms were used, and the results thus obtained were computer-processed. In the maternity hospital of the "mother-child" type the microbial colonization of the laryngeal mucosa by normal and opportunistic microorganisms was noted in newborn infants. A wave-like course of the formation of laryngeal microflora, indicative of microbial succession occurring in the child, was revealed. The attempt to establish the cases of microbial interference between the species colonizing the laryngeal mucosa revealed that it was very rarely observed in 5-day-old newborns. This feature was seemingly the cause of low resistance of the larynx to colonization in newborn infants, which determined frequent colonization of their laryngeal mucosa with Staphylococcus aureus and Klebsiella.     

An Anionic Phospholipid Enables the Hydrophobic Surfactant Proteins to Alter Spontaneous Curvature

The hydrophobic surfactant proteins, SP-B and SP-C, greatly accelerate the adsorption of the surfactant lipids to an air/water interface. Previous studies of factors that affect curvature suggest that vesicles may adsorb via a rate-limiting structure with prominent negative curvature, in which the hydrophilic face of the lipid leaflets is concave. To determine if SP-B and SP-C might promote adsorption by inducing negative curvature, we used small-angle x-ray scattering to test whether the physiological mixture of the two proteins affects the radius of cylindrical monolayers in the inverse hexagonal phase. With dioleoyl phosphatidylethanolamine alone, the proteins had no effect on the hexagonal lattice constant, suggesting that the proteins fail to insert into the cylindrical monolayers. The surfactant lipids also contain ∼10% anionic phospholipids, which might allow incorporation of the cationic proteins. With 10% of the anionic dioleoyl phosphatidylglycerol added to dioleoyl phosphatidylethanolamine, the proteins induced a dose-related decrease in the hexagonal lattice constant. At 30°C, the reduction reached a maximum of 8% relative to the lipids alone at ∼1% (w/w) protein. Variation of NaCl concentration tested whether the effect of the protein represented a strictly electrostatic effect that screening by electrolyte would eliminate. With concentrations up to 3 M NaCl, the dose-related change in the hexagonal lattice constant decreased but persisted. Measurements at different hydrations determined the location of the pivotal plane and proved that the change in the lattice constant produced by the proteins resulted from a shift in spontaneous curvature. These results provide the most direct evidence yet that the surfactant proteins can induce negative curvature in lipid leaflets. This finding supports the model in which the proteins promote adsorption by facilitating the formation of a negatively curved, rate-limiting structure.     

35S promoter methylation in kanamycin-resistant kalanchoe (<Emphasis Type="Italic">Kalanchoe pinnata</Emphasis> L.) plants expressing the antimicrobial peptide cecropin P1 transgene

Transgenic kalanchoe plants (Kalanchoe pinnata L.) expressing the antimicrobial peptide cecropin P1 gene (cecP1) under the control of the 35S cauliflower mosaic virus 35S RNA promoter and the selective neomycin phosphotransferase II (nptII) gene under the control of the nopaline synthase gene promoter were studied. The 35S promoter methylation and the cecropin P1 biosynthesis levels were compared in plants growing on media with and without kanamycin. The low level of active 35S promoter methylation further decreases upon cultivation on kanamycin-containing medium, while cecropin P1 synthesis increases.     

Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen,Legionella pneumophila

Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector–effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector–effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila‐translocated substrates. While capturing all known examples of effector–effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct—a hallmark of an emerging class of proteins called metaeffectors, or “effectors of effectors”. Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector–effector modulation, may be a common feature of many intracellular pathogens—with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell.     

Induction and genetic identification of a callus‐like growth developed in the brown alga Fucus vesiculosus

Induction of an axenic filamentous‐like callus growth from the brown algae Fucus vesiculosus is described. Different treatments were investigated in various combinations to develop axenic cultures based on identification of surface symbionts via 18S ribosomal RNA. Moreover, viability was confirmed after such processes by 2,3,5‐triphenyl tetrazolium chloride assay that demonstrated an average viability of 29%, relative to nonsterilized explants. After six weeks of a phototrophic cultivation on artificial sea water‐12‐nitrilotriacetic acid (0.5% w/v agar), a filamentous‐like callus growth was observed, which was identified genetically through its mitochondrial DNA after subculturing. Achievement of confirmed marine callus cultures might enrich old previously established blue biotechnology techniques and open new chances for cultivation of brown algae for production of good manufacturing practice‐compliant bioproducts.     

Spinal cord tissue affects sprouting from aortic fragments in ex vivo co‐culture

It is a well‐known fact, that there is a close interconnection between vascular and neural structures in both embryonic development and postnatal life. Different models have been employed to dissect the mechanisms of these interactions, ranging from in vitro systems (e.g., co‐culture of neural and endothelial cells) to in vivo imaging of central neural system recovery in laboratory animals after artificially induced trauma. Nevertheless, most of these models have serious limitations. Here, we describe an ex vivo model, representing an organotypic co‐culture of aortic fragments (AF) with longitudinal slices of mouse neonatal spinal cord (SC) or dorsal root ganglia (DRG). The samples were co‐cultured in a medium adapted for SC tissue and lacking any pro‐angiogenic or neurotrophic growth factors. It was found, that cultivation of AFs in the SC injury zone (transversal dissection of a SC slice) resulted in the initiation of active aortic sprouting. Remarkably, the endothelial cells exiting the AFs never invaded the SC tissue, concentrating in a nearby area (negative taxis). In contrast, the DRGs, while also promoting the sprouting, were a target of active endothelial CD31⁺ cell invasion (positive taxis). Thus, the tissues of both central and peripheral nervous systems have a prominent positive effect on aortic sprouting, while the vector of endothelial cell expansion is strictly nervous‐tissue‐type dependent. The ex vivo AF co‐culture with SC or DRG appeared to be a useful and promising model for a further endeavor into the mechanisms driving the complex interactions between neural and endothelial tissues.     

Wolframin deficiency is accompanied with metabolic inflexibility in rat striated muscles

The protein wolframin is localized in the membrane of the endoplasmic reticulum (ER), influencing Ca2+ metabolism and ER interaction with mitochondria, but the exact role of the protein remains unclear. Mutations in Wfs1 gene cause autosomal recessive disorder Wolfram syndrome (WS). The first symptom of the WS is diabetes mellitus, so accurate diagnosis of the disease as WS is often delayed. In this study we aimed to characterize the role of the Wfs1 deficiency on bioenergetics of muscles. Alterations in the bioenergetic profiles of Wfs1-exon-5-knock-out (Wfs1KO) male rats in comparison with their wild-type male littermates were investigated using high-resolution respirometry, and enzyme activity measurements. The changes were followed in oxidative (cardiac and soleus) and glycolytic (rectus femoris and gastrocnemius) muscles. There were substrate-dependent alterations in the oxygen consumption rate in Wfs1KO rat muscles. In soleus muscle, decrease in respiration rate was significant in all the followed pathways. The relatively small alterations in muscle during development of WS, such as increased mitochondrial content and/or increase in the OxPhos-related enzymatic activity could be an adaptive response to changes in the metabolic environment. The significant decrease in the OxPhos capacity is substrate dependent indicating metabolic inflexibility when multiple substrates are available.