Lights out: the evolution of bacterial bioluminescence in Loliginidae

Representatives of several metazoan clades engage in symbiotic interactions with bioluminescent bacteria, but the evolution and maintenance of these interactions remain poorly understood. Uroteuthis is a genus of loliginid squid (Cephalopoda: Loliginidae) characterized by paired ventral photophores (light organs) housing bioluminescent bacteria. While previous phylogenetic studies have suggested that Uroteuthis is closely related to Loliolus, a genus of non-bioluminescent species, this relationship remains unresolved. To illuminate Uroteuthis and Loliolus phylogeny and its implications for the evolution of bioluminescence in Loliginidae, we generated sequences from two mitochondrial genes from Uroteuthis specimens sampled from several sites in the Indian and western Pacific Oceans. We combined these data with data from GenBank, analyzed the concatenated data set using maximum likelihood and Bayesian methods, and reconstructed the evolution of bacterial bioluminescence on the resulting phylogenies. Our analyses support the hypothesis that Uroteuthis is paraphyletic with respect to Loliolus. Furthermore, our reconstructions suggest that the symbiosis between loliginid squid and bioluminescent bacteria evolved once in the ancestor of Loliolini (the clade comprising Uroteuthis and Loliolus), but was subsequently lost in the ancestor of Loliolus. These findings could have profound implications for our understanding of the evolution of symbiotic bioluminescence in squid.     

The control of lipid metabolism by mRNA splicing in Drosophila

The storage of lipids is an evolutionarily conserved process that is important for the survival of organisms during shifts in nutrient availability. Triglycerides are stored in lipid droplets, but the mechanisms of how lipids are stored in these structures are poorly understood. Previous in vitro RNAi screens have implicated several components of the spliceosome in controlling lipid droplet formation and storage, but the in vivo relevance of these phenotypes is unclear. In this study, we identify specific members of the splicing machinery that are necessary for normal triglyceride storage in the Drosophila fat body. Decreasing the expression of the splicing factors U1-70K, U2AF38, U2AF50 in the fat body resulted in decreased triglyceride levels. Interestingly, while decreasing the SR protein 9G8 in the larval fat body yielded a similar triglyceride phenotype, its knockdown in the adult fat body resulted in a substantial increase in lipid stores. This increase in fat storage is due in part to altered splicing of the gene for the β-oxidation enzyme CPT1, producing an isoform with less enzymatic activity. Together, these data indicate a role for mRNA splicing in regulating lipid storage in Drosophila and provide a link between the regulation of gene expression and lipid homeostasis.     

Early predictors of cardiac decompensation in experimental volume overload

The adaptation to chronic hypoxia confers long-lasting cardiac protection against acute ischemia–reperfusion injury. Protein kinase C (PKC) appears to play a role in the cardioprotective mechanism but the involvement of individual PKC isoforms remains unclear. The aim of this study was to examine the effects of chronic intermittent hypoxia (CIH; 7,000 m, 8 h/day) and acute administration of PKC-δ inhibitor (rottlerin, 0.3 mg/kg) on the expression and subcellular distribution of PKC-δ and PKC-ε in the left ventricular myocardium of adult male Wistar rats by Western blot and quantitative immunofluorescence microscopy. CIH decreased the total level of PKC-ε in homogenate without affecting the level of phosphorylated PKC-ε (Ser729). In contrast, CIH up-regulated the total level of PKC-δ as well as the level of phosphorylated PKC-δ (Ser643) in homogenate. Rottlerin partially reversed the hypoxia-induced increase in PKC-δ in the mitochondrial fraction. Immunofluorescent staining of ventricular cryo-sections revealed increased co-localization of PKC-δ with mitochondrial and sarcolemmal membranes in CIH hearts that was suppressed by rottlerin. The formation of nitrotyrosine as a marker of oxidative stress was enhanced in CIH myocardium, particularly in mitochondria. The expression of total oxidative phosphorylation complexes was slightly decreased by CIH mainly due to complex II decline. In conclusion, up-regulated PKC-δ in CIH hearts is mainly localized to mitochondrial and sarcolemmal membranes. The inhibitory effects of rottlerin on PKC-δ subcellular redistribution and cardioprotection (as shown previously) support the view that this isoform plays a role in the mechanism of CIH-induced ischemic tolerance.     

Formation and function of a new pollen aperture pattern in angiosperms: The proximal sulcus of Tillandsia leiboldiana (Bromeliaceae)

Pollen grains are generally surrounded by an extremely resistant wall interrupted in places by apertures that play a key role in reproduction; pollen tube growth is initiated at these sites. The shift from a proximal to distal aperture location is a striking innovation in seed plant reproduction. Reversals to proximal aperture position have only very rarely been described in angiosperms. The genus Tillandsia belongs to the Bromeliaceae family, and its aperture pattern has been described as distal monosulcate, the most widespread aperture patterns recorded in monocots and basal angiosperms. Here we report developmental and functional elements to demonstrate that the sulcate aperture in Tillandsia leiboldiana is not distal as previously described but proximal. Postmeitotic tetrad observation indicates unambiguously the proximal position of the sulcus, and in vitro germination of pollen grains confirms that the aperture is functional. This is the first report of a sulcate proximal aperture with proximal germination. The observation of microsporogenesis reveals specific features in the patterns of callose thickenings in postmeiotic tetrads.     

B cells from rheumatoid arthritis patients show important alterations in the expression of CD86 and FcγRIIb,which are modulated by anti-tumor necrosis factor therapy

Introduction  

Several molecules help preserve peripheral B cell tolerance, but when altered, they may predispose to autoimmunity. This work studied the expression of the costimulatory molecule CD86 and the inhibitory receptor for IgG immune complexes FcγRIIb (CD32b), on B cells from rheumatoid arthritis (RA) patients, and the influence of anti-tumor necrosis factor (TNF) therapy.     

Tyrosine-Phosphorylated Caveolin-1 Blocks Bacterial Uptake by Inducing Vav2-RhoA-Mediated Cytoskeletal Rearrangements

Certain bacterial adhesins appear to promote a pathogen''s extracellular lifestyle rather than its entry into host cells. However, little is known about the stimuli elicited upon such pathogen host-cell interactions. Here, we report that type IV pili (Tfp)-producing Neisseria gonorrhoeae (P⁺GC) induces an immediate recruitment of caveolin-1 (Cav1) in the host cell, which subsequently prevents bacterial internalization by triggering cytoskeletal rearrangements via downstream phosphotyrosine signaling. A broad and unbiased analysis of potential interaction partners for tyrosine-phosphorylated Cav1 revealed a direct interaction with the Rho-family guanine nucleotide exchange factor Vav2. Both Vav2 and its substrate, the small GTPase RhoA, were found to play a direct role in the Cav1-mediated prevention of bacterial uptake. Our findings, which have been extended to enteropathogenic Escherichia coli, highlight how Tfp-producing bacteria avoid host cell uptake. Further, our data establish a mechanistic link between Cav1 phosphorylation and pathogen-induced cytoskeleton reorganization and advance our understanding of caveolin function.     

Synthesis of novel pyrazolic analogues of chalcones and their 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazole derivatives as potential antitumor agents

Novel (E)-1-aryl-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones 5/6 (pyrazolic chalcones) were synthesized from a Claisen–Schmidt reaction of 3-aryl-1-phenylpyrazol-4-carboxaldehydes 4 with several acetophenone derivatives 1. Subsequently, the microwave-assisted cyclocondensation reaction of chalcones 5/6 with hydrazine afforded the new racemic 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazoles 7 or their N-acetyl derivatives 8 and 9 when reactions where carried out in DMF or acetic acid, respectively. Several of these compounds were screened by the US National Cancer Institute (NCI) for their ability to inhibit 60 different human tumor cell lines, where 5c and 9g showed remarkable activity mainly against leukemia (K-562 and SR), renal cancer (UO-31) and non-small cell lung cancer (HOP-92) cell lines, with the most important GI₅₀ values ranging from 0.04 to 11.4 μM, from the in vitro assays.     

Antibacterial activity against β- lactamase producing Methicillin and Ampicillin-resistants Staphylococcus aureus: fractional Inhibitory Concentration Index (FICI) determination

Background

The present study reports the antibacterial capacity of alkaloid compounds in combination with Methicillin and Ampicillin-resistants bacteria isolated from clinical samples. The resistance of different bacteria strains to the current antibacterial agents, their toxicity and the cost of the treatment have led to the development of natural products against the bacteria resistant infections when applied in combination with conventional antimicrobial drugs.

Method

The antibacterial assays in this study were performed by using inhibition zone diameters, MIC, MBC methods, the time-kill assay and the Fractional Inhibitory Concentration Index (FICI) determination. On the whole, fifteen Gram-positive bacterial strains (MRSA/ARSA) were used. Negative control was prepared using discs impregnated with 10 % DMSO in water and commercially available Methicillin and Ampicillin from Alkom Laboratories LTD were used as positive reference standards for all bacterial strains.

Results

We noticed that the highest activities were founded with the combination of alkaloid compounds and conventional antibiotics against all bacteria strains. Then, results showed that after 7 h exposition there was no viable microorganism in the initial inoculums.

Conclusion

The results of this study showed that alkaloid compounds in combination with conventional antibiotics (Methicillin, Ampicillin) exhibited antimicrobial effects against microorganisms tested. These results validate the ethno-botanical use of Cienfuegosia digitata Cav. (Malvaceae) in Burkina Faso. Moreover, this study demonstrates the potential of this herbaceous as a source of antibacterial agent that could be effectively used for future health care purposes.     

Traceability of Marketable Japanese Shoro in New Zealand: Using Multiplex PCR To Exploit Phylogeographic Variation among Taxa in the Rhizopogon Subgenus Roseoli

Rhizopogon roseolus Corda (synonym Rhizopogon rubescens Tul.), an economically important edible mushroom associated with the Pinaceae (mostly Pinus sp.), has a global distribution resulting from the introduction of exotic trees into the Southern Hemisphere for plantation forestry. However, the marketability of R. roseolus varies with the place of origin. R. roseolus strains cultivated in New Zealand from local carpophores for the Japanese market are morphologically and biologically distinct from those produced in Japan and are consequently considered less valuable. In this study, the ITS1-5.8S-ITS2 rRNA (internal transcribed spacer [ITS]) region was used to examine the phylogenetic relationships of R. roseolus and other closely related fungi belonging to Rhizopogon subgenus Roseoli to determine the genetic basis for phenotypic differences among R. roseolus isolates from different geographic regions. Phylogenetic comparison revealed phylogeographic variation within Rhizopogon subgenus Roseoli. Collections from the United States and Europe grouped into four distinct clades. Rhizopogon roseolus isolates found in New Zealand were closely related to those from the United States, likely due to introduction of Pinus radiata from its native California in the United States. In contrast, Japanese R. roseolus isolates clustered closely with European collections. Phylogenetic differences between Japanese and New Zealand R. roseolus isolates may explain the morphological and biological properties attributed to these geographical variants. The ITS region was subsequently used to design a multiplex PCR for the simultaneous identification of Japanese and New Zealand R. roseolus isolates to track the establishment of ectomycorrhiza on P. radiata seedlings inoculated with commercially valuable R. roseolus. This diagnostic demonstrated the first fruiting of Japanese shoro cultivated on P. radiata in the Southern Hemisphere.Since the latter half of the 19th century, Northern Hemisphere species of exotic trees, in particular Pinus radiata, have been planted in the Southern Hemisphere (e.g., Chile, Argentina, South Africa, Australia, and New Zealand). Indeed, over 1,000,000 ha of exotic trees have been established in New Zealand alone (32, 9). Over 200 nonnative basidiomycete and ascomycete ectomycorrhizal (ECM) fungal species are associated with Pinus or Eucalyptus plantations in the Southern Hemisphere from the introduction of plants with intact root systems (46).The genus Rhizopogon Fries (Basidiomycota, Boletales) contains more than 100 species of hypogeous fungi (24), which form ECM associations mostly with members of the Pinaceae (44). The greatest diversity of Rhizopogon can be found in the coniferous forests of the Pacific northwestern United States (40, 30), although a number of species are known to occur in Europe (40) and Asia (3). At least four introduced species of Rhizopogon have also been reported in New Zealand, including R. clelandii Cunn., R. luteolus Fr., R. roseolus (7), and R. vinicolor A. H. Smith (5). At least two species, R. luteolus and R. roseolus, have been associated with P. radiata seedlings in forest nurseries in the North Island of New Zealand (6).In Japan, R. roseolus is known locally as shoro. Shoro is considered a delicacy (20), and its production is dependent on the collection of the carpophores in the field. In fact, only 200 years ago, shoro was the fourth most commonly consumed mushroom in Japan (34). However, the number of natural shoro has declined in the second half of the 20th century (15), resulting in its cultivation in forestry plantations since the late 1980s (50). To fulfill Japanese demand, plantations of P. radiata artificially inoculated with R. roseolus have been established in New Zealand since 1999 using spores from fruiting bodies collected locally (47). Three of the four plantations have subsequently produced fruiting bodies, but the crop has been deemed unsuitable due to consumer sensitivity in Japan to the origin of the products and doubts surrounding the authenticity of the fruiting bodies as Japanese shoro. The quality and market price of other edible fungi differ not only with species but also with their origin. In Japan, domestic Tricholoma matsutake is considered the premium source of matsutake, traded at $500/kg, while South Korean matsutake and those from China are considered less valuable ($250/kg and $100/kg, respectively) (31). Highly prized edible fungi have also been found to be contaminated with less valuable species. Tuber rufum Pico is a truffle species that is found alongside other valuable species in countries where truffles are commercially important. However, it is considered to be a poorly flavored species with no marketable value and is deemed a “contaminant” in truffières (4).Unfortunately, the taxonomy of the genus Rhizopogon is surrounded by many unresolved issues, which makes differentiation of shoro-like fungi found in different geographical locations difficult. In 1966, Smith and Zeller (40) completed the first taxonomic study of the genus Rhizopogon, dividing it into two subgenera, Rhizopogonella (subsequently transferred to Alpova [45]) and Rhizopogon. The subgenus Rhizopogon was further divided into four sections based on differences in the host plant, sporocarp morphology, and color of the peridium. All species associated with Pinus spp. were classified in Rhizopogon section Rhizopogon. Rhizopogon roseolus and R. rubescens were placed in subsection Angustispori, stirps Rubescens. A third species, Rhizopogon vulgaris Vittad., was placed in subsection Angustispori, stirps Vulgaris, due to differences in its spore morphology.Similarities between species in stirps Rubescens and stirps Vulgaris were recorded, with stirps Vulgaris considered a continuation of stirps Rubescens into the narrow-spore species. However, classification was based only on examinations of North American collections even though these species were originally described in Europe in the 19th century (40). Taxonomic reexamination of Rhizopogon using phylogenetic analyses of internal transcribed spacer (ITS) DNA sequences showed that Rhizopogon burlinghamii, R. roseolus, and R. vulgaris formed Rhizopogon section Rhizopogon clade C, separate from the other species sampled from section Rhizopogon (clades A and B). Their ITS sequences lacked insertions and deletions that are diagnostic of other section Rhizopogon clades. Rhizopogon roseolus and R. vulgaris were placed together under Rhizopogon subgenus Roseoli (13). Unfortunately, collections classified as R. rubescens were not included in the phylogenetic study. More recently, species concepts in the R. roseolus species group were examined by Martín and García (25). ITS sequence analyses separated the collections into five possible phylogenetic species.The continued taxonomic instability of Rhizopogon subgenus Roseoli has created ongoing confusion, and the correct species names are still not clear. In Japan, until now, shoro has been referred to as R. rubescens; however, R. rubescens is used widely as a synonym for R. roseolus. In this study, R. roseolus will be used to describe all collections unless specifically stated, as this taxonomic name appears to have precedence in previous phylogenetic studies of Rhizopogon (13, 19, 40) and since Mycobank (http://www.MycoBank.org/) considers R. rubescens to be a synonym of R. roseolus.Molecular diagnostic tools capable of distinguishing genetic differences in ECM fungi have been developed, allowing the differentiation of commercially important species from contaminants or similar species of less economic value. There are many studies where PCR primers designed for the amplification of the ITS region have been used to identify basidiomycetes (12, 18). Species-specific primers were created to identify and differentiate marketable boletes (28), to detect black truffle species (37), and to distinguish Asiatic black truffles from Tuber melanosporum in commercialized products (22). A multiplex PCR has also been developed to simultaneously detect different white truffle species and one of the most aggressive contaminant fungi for monitoring the persistence of a selected truffle in inoculated seedlings (1).Due to the sensitivity of consumers to the origins of shoro and the existing taxonomic complexity of the genus Rhizopogon, morphological and molecular methods were used to establish the diversity and genetic structure of Rhizopogon subgenus Roseoli. Phylogenetic relationships between shoro-like species (originally classified as R. vulgaris, R. rubescens, and R. roseolus) from different geographical locations were investigated to verify previously observed differences between shoro grown in Japan and New Zealand. A multiplex PCR was then developed for the rapid identification of ECMs and fruiting bodies grown from Japanese shoro in New Zealand to track the commercial production of this economically valuable edible fungus.