Snapshot of an early Paleoproterozoic ecosystem: Two diverse microfossil communities from the Turee Creek Group,Western Australia

Eighteen microfossil morphotypes from two distinct facies of black chert from a deep‐water setting of the c. 2.4 Ga Turee Creek Group, Western Australia, are reported here. A primarily in situ, deep‐water benthic community preserved in nodular black chert occurs as a tangled network of a variety of long filamentous microfossils, unicells of one size distribution and fine filamentous rosettes, together with relatively large spherical aggregates of cells interpreted as in‐fallen, likely planktonic, forms. Bedded black cherts, in contrast, preserve microfossils primarily within, but also between, rounded clasts of organic material that are coated by thin, convoluted carbonaceous films interpreted as preserved extracellular polymeric substance (EPS). Microfossils preserved within the clasts include a wide range of unicells, both much smaller and larger than those in the nodular black chert, along with relatively short, often degraded filaments, four types of star‐shaped rosettes and umbrella‐like rosettes. Large, complexly branching filamentous microfossils are found between the clasts. The grainstone clasts in the bedded black chert are interpreted as transported from shallower water, and the contained microfossils thus likely represent a phototrophic community. Combined, the two black chert facies provide a snapshot of a microbial ecosystem spanning shallow to deeper‐water environments, and an insight into the diversity of life present during the rise in atmospheric oxygen. The preserved microfossils include two new, distinct morphologies previously unknown from the geological record, as well as a number of microfossils from the bedded black chert that are morphologically similar to—but 400–500 Ma older than—type specimens from the c. 1.88 Ga Gunflint Iron Formation. Thus, the Turee Creek Group microfossil assemblage creates a substantial reference point in the sparse fossil record of the earliest Paleoproterozoic and demonstrates that microbial life diversified quite rapidly after the end of the Archean.     

Engineered exosomes: A new promise for the management of musculoskeletal diseases

Background

Exosomes are nanovesicles actively secreted by potentially all cell types, including tumour cells, with the primary role of extracellular systemic communication mediators, both at autocrine and paracrine levels, at short and long distances. Recently, different studies have used exosomes as a delivery system for a plethora of different molecules, such as drugs, microRNAs and proteins. This has been made possible thanks to the simplicity in exosomes engineering, their great stability and versatility for applications in oncology as well as in regenerative medicine.

Protective immunity induced by an intranasal multivalent vaccine comprising 10 Lactococcus lactis strains expressing highly prevalent M‐protein antigens derived from Group A Streptococcus

Streptococcus pyogenes (group A Streptococcus) causes diseases ranging from mild pharyngitis to severe invasive infections. The N‐terminal fragment of streptococcal M protein elicits protective antibodies and is an attractive vaccine target. However, this N‐ terminal fragment is hypervariable: there are more than 200 different M types. In this study, an intranasal live bacterial vaccine comprising 10 strains of Lactococcus lactis, each expressing one N‐terminal fragment of M protein, has been developed. Live bacterial‐vectored vaccines cost less to manufacture because the processes involved are less complex than those required for production of protein subunit vaccines. Moreover, intranasal administration does not require syringes or specialized personnel. Evaluation of individual vaccine types (M1, M2, M3, M4, M6, M9, M12, M22, M28 and M77) showed that most of them protected mice against challenge with virulent S. pyogenes. All 10 strains combined in a 10‐valent vaccine (M×10) induced serum and bronchoalveolar lavage IgG titers that ranged from three‐ to 10‐fold those of unimmunized mice. After intranasal challenge with M28 streptococci, survival of M×10‐immunized mice was significantly higher than that of unimmunized mice. In contrast, when mice were challenged with M75 streptococci, survival of M×10‐immunized mice did not differ significantly from that of unimmunized mice. Mx‐10 immunized mice had significantly less S. pyogenes in oropharyngeal washes and developed less severe disease symptoms after challenge than did unimmunized mice. Our L. lactis‐based vaccine may provide an alternative solution to development of broadly protective group A streptococcal vaccines.

     

Epidemiological characterization of serotype group B Streptococci neonatal infections associated with interleukin-6 level as a sensitive parameter for the early diagnosis

Group B streptococcal infection (Streptococcus agalactiae) is one of the leading causes of life-threatening disease in the early neonatal period, resulting in sepsis, pneumonia, and meningitis. During invasive infections, an excessive release of pro-inflammatory cytokine, such as interleukin-6 (IL-6), thus IL-6 gene is significant, as a diagnostic marker of systemic infection of the newborns. The present study aimed to describe the epidemiology diagnostic of GBS disease in neonatal by phenotypic and genotypic methods. Nine hundred and ninety-six samples were taken at Maternity and Children Hospital, Jeddah, Saudi Arabia for a period of one year (2011–2012). Results indicated that out of 217 infected samples, twenty (9.23.0%) were positive for group B Streptococci bacteria. This study also shows that female infants are more susceptible than males. The level of IL-6 was higher in mothers above 30 years. Twenty positive Streptococci group B isolates showed bands with the cylE gene primers in the border between 228 bp, 267 bp and 50 bp. Molecular detection by Real time polymerase chain reaction was also done to detect the target (Sip gene) encoding the Sip surface immunogenic protein. Specific primers and TaqMan probe were chosen for this purpose. A Real-time PCR method targeting the sip gene of GBS in neonates after delivery has been evaluated.     

Wide-Range Distribution of Insertion Sequences Identified in B. halodurans among Bacilli and a New Transposon Disseminated in Alkaliphilic and Thermophilic Bacilli

All of the insertion sequences (ISs) except for IS663 and agroup II intron identified in the alkaliphilic Bacillus haloduransC-125 genome were also detected in nine other strains of thesame species by PCR and Southern blot analysis. The transposaseof IS653 identified in the genomes of the 10 strains of B. haloduranswas found to have become the most diversified of all ISs identifiedin the genomes of 10 strains. A new IS element designated IS661belonging to the IS1380 family with inverted repeats (IRs) 17bp in length was present within IS658 identified in the genomeof B. halodurans A59. In addition, a new transposon designatedTn3271bh was identified within the IS642 element in the A59genome, which is similar to a transposon identified in thermophilicGeobacillus stearothermophilus T-6. The new transposon, Tn3271bh,generated an 8-bp duplication of the target site sequence andcarries a 21-bp IR. On the other hand, all kinds of ISs exceptfor IS643 and IS658 were distributed in the genome of obligatelyalkaliphilic Bacillus alcalophilus. Three ISs (IS652, IS653,and IS660) and a group II intron (Bh.Int) were widely dispersedin other Bacillus species without a correlation with the phylogeneticplacement based on 16S rDNA sequences.     

REVISION OF THE ARCHOSAUROMORPH REPTILE TRILOPHOSAURUS, WITH A DESCRIPTION OF THE FIRST SKULL OF TRILOPHOSAURUS JACOBSI, FROM THE UPPER TRIASSIC CHINLE GROUP, WEST TEXAS, USA

Abstract: The first abundant, well‐preserved fossils of the unusual archosauromorph reptile Trilophosaurus jacobsi Murry are from an Upper Triassic bonebed in the lowermost Trujillo Formation of the Chinle Group in Borden County, Texas. A nearly complete left side of the skull and incomplete but articulated mandible of a juvenile individual demonstrate that Trilophosaurus jacobsi Murry is referable to Trilophosaurus, so the putative procolophonid genus Chinleogomphius is a junior objective synonym of Trilophosaurus. Features of T. jacobsi that diagnose it from T. buettneri include asymmetrical, tricuspate teeth in which the central cusp is taller than the marginal cusp, polygonal in cross‐section and displaced slightly lingually; the lingual cusp is low, transversely broadened and anteroposteriorly compressed; teeth with prominent cingula along the mesial and distal margins; and paired sagittal (parasagittal) crests composed of portions of the postfrontals and the parietals, as well as a relatively broad skull roof between the supratemporal fenestrae. We also re‐illustrate and re‐describe the holotypes of both Trilophosaurus buettneri Case and T. jacobsi Murry. T. jacobsi is primarily Adamanian in age, and the lowest occurrence of T. jacobsi is stratigraphically above that of T. buettneri. Therefore, T. buettneri is an Otischalkian–Adamanian index taxon, and T. jacobsi is an Adamanian–?earliest Revueltian index taxon. Trilophosaurus teeth are readily identifiable to species and therefore identifiable as isolated fossils.     

Humoral antibody response and Ig characterization of the specific agglutinins in rabbits during experimental American trypanosomiasis

A comparative follow up study of the specific agglutinins detected by direct agglutination (DA) test and the immune response detected by specific lysis (SL), indirect immunofluorescence (IFA), indirect hemagglutination (IHA) and complement fixation (CF) tests in rabbits inoculated with trypomastigotes of T. cruzi is reported here.The specific antibody response was detected first by DA test. Reductive cleavage of sera with 2-mercaptoethanol produced a drop in the agglutinin titer of the sera during the first 30 days of infection.The next test to become positive was SL and later on the IFA, IHA and CF tests became positive simultaneously.When fractions obtained by column chromatography in Sephadex G-200 were tested serologically it was demonstrated that specific antibodies were detected mainly in fraction I (IgM) of the pooled rabbit sera obtained 15 days after inoculation (acute stage), and in fraction II (IgG) of the pooled sera obtained from rabbits 90 days after inoculation (chronic stage).Antigens prepared with trypsinized and formolized epimastigotes of three T. cruzi strains, belonging to each one of the different immunological groups described, worked similarly in the detection of specific agglutinin antibodies.Trypanosoma cruzi agglutinins were highly specific in their reaction with their homologous T. cruzi antigens as was proved by the low agglutinin titer obtained in sera from infected rabbits when, instead of T. cruzi epimastigotes, promastigotes of L. donovani were used as antigen, and by the incapacity of this parasite to absorb the T. cruzi agglutinins.     

Structural basis for substrate specificity of meso-diaminopimelic acid decarboxylase from Corynebacterium glutamicum

l-lysine is an essential amino acid that is widely used as a food supplement for humans and animals. meso-Diaminopimelic acid decarboxylase (DAPDC) catalyzes the final step in the de novol-lysine biosynthetic pathway by converting meso-diaminopimelic acid (meso-DAP) into l-lysine by decarboxylation reaction. To elucidate its molecular mechanisms, we determined the crystal structure of DAPDC from Corynebacterium glutamicum (CgDAPDC). The PLP cofactor is bound at the center of the barrel domain and forms a Schiff base with the catalytic Lys75 residue. We also determined the CgDAPDC structure in complex with both pyridoxal 5′-phosphate (PLP) and the l-lysine product and revealed that the protein has an optimal substrate binding pocket to accommodate meso-DAP as a substrate. Structural comparison of CgDAPDC with other amino acid decarboxylases with different substrate specificities revealed that the position of the α15 helix in CgDAPDC and the residues located on the helix are crucial for determining the substrate specificities of the amino acid decarboxylases.     

Elucidating Ernietta: new insights from exceptional specimens in the Ediacaran of Namibia

Exceptionally preserved specimens of Ernietta in a shallow‐marine gutter cast from southern Namibia reveal that all previously figured specimens of this iconic Ediacaran megafossil are incomplete, representing only the base of a larger and more complex organism. The complete organism is interpreted as comprising a buried, sand‐filled anchor exhibiting the classical Ernietta morphology that passes distally into a trunk that is crowned by two facing fans that extended into the overlying water column. All parts of Ernietta, from the base of its buried anchor to the tip of its fans, appear to have been composed of a palisade of tubular elements that have been variably preserved. Similarity of tubule morphology despite the inherent difference in function between these constructions supports the view that these tubes were integral to all anatomical parts and functions of Ernietta. This style of architecture, construction and function is unique to the Erniettomorpha, supporting the view that it represents an extinct Ediacaran clade in the early evolution of multi‐cellular life.