Bacterial Forms Research Articles

Management of pericarditis and pericardial effusion, constrictive and effusive-constrictive pericarditis

This CME review takes stock of the progress in the etiology, pathophysiology, diagnostics and treatment of pericarditis and pericardial effusion brought about by the publication of the 2nd European Society of Cardiology (ESC) guidelines on the management of pericardial diseases in 2015. It also emphasizes special forms, which have received less attention in the past, such as therapy-refractory (incessant), effusive-constrictive and constrictive pericarditis and the treatment of acute and recurrent pericarditis with colchicine. After the diagnosis of pericarditis with or without effusion has been made, the first step is to clarify its etiology, which affects the clinical symptoms, course, treatment and the prognosis. In this aspect the requirements of the guidelines and the reality of an etiological classification of pericardial diseases diverge in many cases. The diagnosis of "idiopathic" acute or recurrent pericarditis is still much too often the result of insufficient efforts to find the cause. Too often only malignant and bacterial forms are excluded. If the etiology is known local intrapericardial treatment with the already inserted pigtail catheter from the diagnostic pericardial puncture can be carried out with few systemic side effects. The 2015 ESC guidelines recommend colchicine as first line treatment in all forms of pericarditis except for neoplastic pericardial effusion. It accelerates healing and reduces the frequency of recurrence of pericarditis but cannot eliminate recurrence completely. The best treatment and prevention of recurrence is the eradication of the underlying etiological cause.

How to fold and protect mitochondrial ribosomal RNA with fewer guanines.

Mammalian mitochondrial ribosomes evolved from bacterial ribosomes by reduction of ribosomal RNAs, increase of ribosomal protein content, and loss of guanine nucleotides. Guanine is the base most sensitive to oxidative damage. By systematically comparing high-quality, small ribosomal subunit RNA sequence alignments and solved 3D ribosome structures from mammalian mitochondria and bacteria, we deduce rules for folding a complex RNA with the remaining guanines shielded from solvent. Almost all conserved guanines in both bacterial and mammalian mitochondrial ribosomal RNA form guanine-specific, local or long-range, RNA–RNA or RNA–protein interactions. Many solvent-exposed guanines conserved in bacteria are replaced in mammalian mitochondria by bases less sensitive to oxidation. New guanines, conserved only in the mitochondrial alignment, are strategically positioned at solvent inaccessible sites to stabilize the ribosomal RNA structure. New mitochondrial proteins substitute for truncated RNA helices, maintain mutual spatial orientations of helices, compensate for lost RNA–RNA interactions, reduce solvent accessibility of bases, and replace guanines conserved in bacteria by forming specific amino acid–RNA interactions.

Microbiological Quality Analysis of Raw and Pasteurized Milk Samples Collected from Addis Ababa and Its Surrounding in Ethiopia

This study was conducted to evaluate microbiological quality of raw and pasteurized milk samples collected from different locations in Ethiopia in 2016/2017G.c. Two types of milk samples were collected from different part of Addis Ababa and its surrounding of selected sites. A total of 48 samples were analyzed including 28 raw milk samples from the local producers, collectors and dairy markets and 20 different brands of pasteurized treated milk samples collected from different processing industries and from super market. The samples were examined for determining the Total Bacterial Count (TBC) and Total Coli form Count (TCC). The results revealed that the raw and half of pasteurized milk samples were substandard in terms of TBC and TCC. No growth in terms of TBC and TCC in sample number Ra-12 and no growth at TCC in sample number Ra-3. The range of TBC and TCC in raw milk samples was 5*103 to 3.18*108cfu/ml and 1.81*102 to 3.08*106cfu/ml, respectively. The TBC and TCC range in pasteurized milk samples was from 4.4*101 to 4.43*105cfu/ml and 4.5*101 to 2.3*104cfu/ml, respectively. In some samples the result was much greater of the recommended level by the Ethiopian Standards Agency /ESA/. Exceptionally sample numbers Pa1-6 and Pa-20 of pasteurized milk samples had no growth at all both in terms of TBC and TCC sample number pa-8, 9, 14, and 15 have no growth in terms of TCC.

Fecal Helicobacter pylori glmM and 16S rRNA genes correlate with serum TNF-α and IL-1β cytokine fluctuations.

The proinflammatory cytokines of TNF-α and IL-1β have been reported to be increased in gastric mucosal surfaces in people with Helicobacter pylori infection. Accordingly, this study was conducted to investigate the relationship between the presence of H. pylori genes and the serum oscillations of these cytokines. In this study, DNA was first extracted from the stool samples of infected individuals and used as DNA template to investigate the presence of glmM and 16S rRNA genes in PCR. The ELISA assay was employed to examine serum levels of TNF-α and IL-1β cytokines. According to statistical analysis, there was a significant correlation between the presence of glmM and 16S rRNA genes in the stool samples of infected persons and the serum oscillations of TNF-α and IL-1β cytokines. At the end of study and analysis of the data in case group with HPSAg+, 47.6% of the glmM gene and 23.6% of the 16S rRNA gene were positive. In addition, a significant correlation was observed between the presence of glmM and 16S rRNA genes in the stool specimens of infected individuals and the serum levels of TNF-α and IL-1β cytokines (p < 0.05). Considering the results, it can be concluded that fluctuations in the amount of HPSA, TNF-α, and IL-1β in H. pylori infection depend on the presence of glmM and 16S rRNA genes. The presence of glmM and 16S rRNA in the stool sample increases by boosting the response level to stool antigen (HPSA), IL-1β, and TNF-α, suggesting the prognosis of the disease with a bacterial virulence form using stool tests.

Using ecological stoichiometry to understand and predict infectious diseases

A key characteristic of host–parasite interactions is the theft of host nutrients by the parasite, yet we lack a general framework for understanding and predicting the interplay of host and parasite nutrition that applies across biological levels of organization. The elemental nutrients (C, N, P, Fe, etc.), and ecological stoichiometry provide a framework for understanding host–parasite interactions and their relation to ecosystem functioning. Here we use the ecological stoichiometry framework to develop hypotheses and predictions regarding the relationship between elemental nutrients and host–parasite interactions. We predict that a suite of host and parasite traits, stoichiometric homeostasis, host diet stoichiometry, and biogeochemical cycling are related to disease dynamics, host immunity and resistance, and bacterial growth form determination. We show that ecological stoichiometry is capable of expanding our understanding of host–parasite interactions, and complementing other approaches such as population and community ecology, and molecular biology, for studying infectious diseases.

Comparative Efficiency of Various Disinfectants Used in the Cattle Farm

Abstract The investigations were aimed to establish the comparative efficiency of four disinfectants (Aquadez, Ecocide S, Virocide and Na OH) used for the disinfection of cattle farm of State Agrarian University of Moldova. According to the classical methodology, the disinfectants have been used in concentrations which were recommended by the producers. Following this, lavages were collected from different supports and equipment of the cattle farm before sparing of the disinfectants and one hour after the contact of the disinfectants with the substrates. In this context samples were taken from places as the feeding space for animals and the rest area, cows’ milking rooms and the milk collection rooms. Afterwards, the samples have been inseminated in laboratory conditions for establishing the afterwards disinfecting effect on the farm. As a result, the microbiological investigation demonstrated that concentrations which were recommended by the producers and double concentrations of disinfectants don’t have satisfactory 100% of the anti-microbial and antifungal effect. For all disinfected places with the mentioned disinfectants colonies of microorganisms grew on nutrient media, especially bacterial forms as Streptococcus, Staphylococcus and microscopic fungal. Following comparisons, Ecocide S 3% and Na OH 3% had a higher efficiency than Aquadez 3%. The after application effect of Aquadez 3% established the presence of Salmonella, E. coli colonies grown on nutrient media as well as, Streptococcus and microscopic fungal.

The Emergence of Endophytic Microbes and Their Biological Promise.

As is true with animal species, plants also have an associated microflora including endophytes as well as microbes associated with the phyllosphere and rhizosphere (plant surfaces) and this is considered the plant microbiome. However, those organisms within virtually all tissues and organs of the plant are known as endophytes. Most often fungi are the most frequently recovered endophytes from plant tissues, but bacterial forms generally occur in greater numbers, but not in species varieties. The exact biological/biochemical role of the endophyte in the plant and how it interacts with the plant and other endophytes and plant associated organisms has not been intensely and carefully examined. However, this has not stopped investigators in exploring the direct utility of endophytes in boosting plant production, and discovering that endophytes can directly influence the plant to resist temperature extremes, drought, as well as the presence of disease causing organisms. Also, because of the relationships that endophytes seem to have with their host plants, they make a myriad of biologically active compounds some of which are classified as antibiotics, antioxidants, anticancer agents, volatile antimicrobial agents, immunosuppressive compounds, plant growth promoting agents, and insecticides. These endophytic compounds represent a wide range of organic molecules including terpenoids, peptides, carbohydrates, aromatics, hydrocarbons and others and it seems that these compounds may have a role in the host microbe relationship. Most recently and quite surprisingly, some endophytes have been discovered that make hydrocarbons of the types found in diesel and gasoline fuels. In addition, recently discovered are epigenetic factors relating to the biology and biochemistry of endophytes. Interestingly, only about 1–2% of the entire spectrum of 300,000 known plants have been studied for their endophyte composition. Additionally, only a few plants have ever been completely studied including all tissues for the microbes within them. Likewise, the vast majority of plants, including those in oceans and lower plant forms, have never been examined for their endophytes. Furthermore, endophytes representing the “microbiome” of world’s major food plants as they exist in their native “centers of origin” are largely unknown. This non-classical review is intended to provide background information on aspects of developments in endophyte biology and more importantly the identification of new questions in this field that need to be addressed. The review is primarily based on the author’s long held experience in this field.

POTENTIALS OF CUMINUM CYMINUM IN MICROBIAL CONTROL

Cumin is one of the important spices known for their distinctive aroma, cumin seeds are sprinkled over popular North African, Middle East, Western, Chinese, Indian, Cuban and Northern Mexican cuisines. The spice is native to middle-east, Asian region, and now grown all over the world for its flavorful seeds. The plant is the small flowering herb belonging to the family of Apiaceae of the genus Cuminum, and scientifically known as Cuminum cyminum. It is an important condiment and spice crop grown in India for its aromatic-seed. India is the leading country in the world in production, consumption and export of cumin. It is grown in Madhya Pradesh, Rajasthan, Gujarat, West Bengal, Assam, Kerala, Uttar Pradesh and Punjab. Cumin is used as condiment for flavor and in medicines. Though cumin is one of the important spice crops with high economic returns, it has not yet gained commercial significance in most of the areas favorable for its cultivation. RS-l variety of cumin plant is recommended for Haryana, Punjab and Rajasthan. Cumin plays an important role in human health owing to their anti-inflammatory, anti-allergic, antimicrobial, anticarcinogenic, antiviral activities. Furthermore, it is anti-diuretic and anti-oxidant. Considering the above facts our study was carried out to observe & evaluate the effect of extracts from cumin against microbial population considering both bacterial & fungal forms. Cumin-acetone fractions were extracted with Soxhlet and considered for tests against Gram negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcus aureus) and the fungi (Aspergillus niger, Penicillium notatum, Mucor indicus). All the observations showed positive results by appearance of clear zone of inhibition on cultured petri plates for bacteria. However, Work on fungal species are on progress. Further, studies are going on MIC and analysis of the extract, which may provide us new ideas in the study of bio-active agents.

The second conserved motif in bacterial laccase regulates catalysis and robustness.

Laccase (EC1.10.3.2), an oxidase that binds multiple copper ions, is heterogeneous in different species, implying diversity in its function. Nevertheless, the four copper-binding motifs are conserved in most laccases, especially bacterial forms. In order to exploit laccase more widely and more effectively in industrial processes, we investigated the regulatory effects, if any, of the second conserved copper-binding motif in the bacterial laccases CAR2 and CAHH1. The data suggested that three critical amino acid residues His155, His157, and Thr/Ala158 in this motif strongly regulated laccase's catalysis, substrate range, and robustness. Indeed, these residues were essential for laccase's catalytic activity. The data also suggested that laccase's catalytic efficiency and activity are not completely consistent with its stability, and that the enzyme might have evolved naturally to its favor stability. This study provides important insights into the second conserved copper-binding motif and defines some of the previously undefined amino acid residues in this conserved motif and their significances.

Characteristics of the composition of the psychrotrophic microflora of frozen beef in the process of storage

In the technological process of obtaining raw materials and food products, the main task is to ensure their safety. During the curing of beef meat, the risks are most often associated with microbial contamination. The purpose of the work was to investigate the dynamics of quantitative content and generic composition of psychrotrophic microflora in the process of storage of frozen beef with different initial microbial sowing. The investigated samples were divided into four groups, depending on the initial content of the psychrotrophic microflora. The first group of psychrotrophic microorganisms was up to 103 CFU/cm3 from the surface; second group of 103 to 104 CFU/cm3 of washed away; the third – from 104 to 105 CFU/cm3 of washed away; the fourth is more than 105 CFU/cm3 of washed away. It was established that during the storage of beef in the frozen state, the rate of development of the psychrotrophic microflora is 3,0-32,6 times faster than the mesophilic microflora. Also it was found the higher the initial microbial sowing of beef, the faster the pace of development of the microflora in the process of storing meat in the frozen state. Therefore, when choosing meat storage conditions (temperature, term), the initial microbial contamination of the carcass surface with a psychrotrophic microflora is important. It was found that from beef with low microbial sowing it is allocated three classes of psychrotrophic bacteria: Acinetobacter, Alcaligenes i Pseudomonas. The largest part of the cooled meat was 56.2 ± 2.4% of the genus Acinetobacter, and the smallest 12.5 ± 0.8% Pseudomonas. After 20 days of storage of beef in the frozen state, the growth of bacteria of the genus Pseudomonas was 1,4 times (P ≤ 0.05) due to the reduction of the Acinetobacter species of microorganisms. At the same time, the bacteria of the genus Alcaligenes were stably high in both frosty and frozen meat – 31.2–32.7%, respectively. Identification of psychrotrophic microflora with an initial content of mesophilic and psychrotrophic microorganisms 6.5 ± 0.5×103 and 4.2 ± 0.2×103 CFU/cm3 of the washed away, has established an increase in the number of identified genera. Among the already identified three genera in the washed away from beef of this group, bacteria of the genus Flavobacterium i Aeromonas are isolated, both in frozen meat and after storage in a frozen state. When identifying a psychrotrophic microflora with a significant initial microbial sowing (the number of mesophilic bacteria is greater than 5.9 ± 0.4 × 104 and psychrotrophic 3.7 ± 0.2×104 CFU/cm3 washed away the surface) was established an increase in generic composition. Thus, in the psychrotrophic microflora, 5 to 10% of bacteria of the Enterobacteriaceae genus, gram-positive sticks and cow's bacterial forms began to stand out from 3 to 5%. Consequently, the conducted searches have found that with an increase in the initial microbial contamination of beef, the quantitative genetic composition of the psychrotrophic microflora increases. As a result, the storage period of frozen beef and the hygienic and technological quality of meat is reduced.

Effects of d-valine on periodontal or peri-implant pathogens: Porphyromonas gingivalis biofilm.

When presented with a surface or an interface, bacteria often grow as biofilms in which cells are held together by an extracellular matrix. Biofilm formation on implants is an initiating factor for their failure. Porphyromonas gingivalis is the primary etiologic bacteria of initiation and progression of periodontal disease. This microorganism is also the risk factor of many systemic diseases, such as cardiovascular disease, diabetes, and pulmonary infection. To date, no medication that can remove such biofilm has been accepted for clinical use. D-valine (D-val) can reportedly inhibit the formation of biofilm and/or trigger the scattering of mature biofilm. Accordingly, this study investigated the effects of d-val on single-species P. gingivalis biofilms in vitro. P. gingivalis grown in brain heart infusion culture with or without d-val was inoculated in 24- or 96-well plates. After incubation for 72hours, biomass via crystal violet staining, extracellular polysaccharide production by biofilms, and scanning electron microscopy (SEM) were used to determine the d-val concentration that can effectively prevent P. gingivalis biofilm formation. Experimental results showed that d-val effectively inhibited biofilm formation at concentrations ≥50mM (mMol/L), and that d-val inhibition increased with increased concentration. Moreover, at high concentrations, the bacterial form changed from the normal baseball form into a rodlike shape. d-val also notably affected extracellular polysaccharide production by P. gingivalis. d-val can inhibit P. gingivalis biofilm formation, and high concentrations can affect bacterial morphology.

The use of the microbial and entomological data for the diagnostics of prescription of death coming

The objective of the present study was to demonstrate the possibility of the diagnostics of prescription of death coming (PDC) based on the results of the studies with the application of the entomological and microbiological methods. The entomological materials included larvae of two dipteran species Stearibia nigriceps (Piophilidae) and Fannia vesparia (Fanniidae) collected from bone tissue fragments and the bony bed. The detailed investigation of the succession of necrophilic insects taking place in the course of decomposition of organic matter and the development of the preimaginal stages of the dipterans made it possible to determine the duration of the period during which the corpse remained in the ambient environment. The microbiological studies made it possible to determine the composition of necrobiome of the bone remains. It included, among other things, the association of soil bacterial forms belonging to the orders Actinomycetales, Pseudomonadales, and Aeromonadales in the combination with the fungi of the order Endomycetales. The enteral microorganisms that trigger putrefaction at the early stages of corpse decomposition were totally absent in the remains that hosted soil microorganisms destroying the hard tissues. The predominance of Actinobacteria in the samples of bone remains gave evidence of active disintegration of the skeletal tissues by the bacterial species inhabiting the local soil milieu. The study demonstrated that the results of the analysis of the microbial constituent of the washouts from the surfaces of the skull and the left upper arm bone of the human corpse were consistent with the conclusion about the prescription of death coming based on the entomological data. It is agued that the development of the methods for the diagnostics of prescription of death coming, including those to be used for the examination of the skeletonized corpses, based on the results of the entomological and microbiological investigations has good prospects as an area of research in the field of forensic medicine.

Mother-to-newborn transmission of mycobacterial L-forms and V\u03b42 T-cell response in placentobiome of BCG-vaccinated pregnant women

The ability of bacteria to exist as a population of self-replicating forms with defective or entirely missing cell wall (L-forms) is an adaptive mechanism for their survival and reproduction under unfavorable conditions. Bacterial mother-to-fetus transfer is a universal phenomenon in the animal kingdom. However, data about vertical transfer of L bacterial forms are extremely scarce. Bacille Calmette-Guérin is an attenuated strain of M. bovis and the only licensed vaccine used for tuberculosis prevention. We already have shown that filterable L-forms of BCG exist freely in the vaccine and are able to reproduce and to form colonies. The present study was focused on the placental microbiome in the context of mother’s BCG vaccination. Here we report an isolation of filterable mycobacterial L-form cultures from gestational tissues and blood of healthy newborns delivered by healthy BCG-vaccinated mothers after normal pregnancy. Of note, vertically transmitted mycobacterial L-forms as a part of placentobiome of the pregnant women didn’t influence the number of resident pathogen-reactive Vδ2 cells. Placenta colonization with mycobacterial L-forms occurs by maternal blood-to-decidua transfer very early in gestation. Together, these data showed that BCG L-forms have the capacity to pass trans-placental barrier and that maternal BCG vaccination affects the placentobiome.

Cyclic Hydroxamic Acid Analogues of Bacterial Siderophores as Iron-Complexing Agents prepared through the Castagnoli-Cushman Reaction of Unprotected Oximes.

The first application of multicomponent chemistry (the Castagnoli-Cushman reaction) toward the convenient one-step preparation of cyclic hydroxamic acids is described. Cyclic hydroxamic acids are close analogues of bacterial siderophores (iron-binding compounds) and form stable complexes with Fe3+ ions as confirmed by spectrophotometric measurements. These compounds are potential components for the design of chelating agents for iron overload disease therapy, as well as siderophore-based carrier systems for antibiotic delivery across the bacterial cell wall.

In Vitro Anti-Helicobacter pylori Activity of Purified Bee Venom Collected from Honeybee (Apis mellifera L.) Workers

This study was to investigate the antimicrobial effect of purified bee venom(PBV) against Helicobacter pylori, which is known to cause gastric ulcer and stomach cancer. Antimicrobial activity was evaluated by minimum inhibitory concentration( MIC), minimum bactericidal concentration(MBC) and time-kill assay of PBV against H. pylori. As a result, there was no significant difference in the antibacterial activity between amoxycillin(positive control) and PBV that have MIC of 0.13±0.036 μg/ml and MBC of 0.26±0.042 μg/ml. In addition, PBV treatment was found to inhibit significantly growth of H. pylori after 4 hr. In order to investigate the morphological changes of H. pylori by bee venom treatment, the morphology of H. pylori was observed by scanning electron microscope(SEM). H. pylori treated with PBV was also showed that the cell wall and cell membrane were completely destroyed, and all of the cell components were leaked out, resulting in the disappearance of the bacterial form. These results suggest that PBV have significant inhibitory effects on H. pylori, and therefore, may be a potential anti-H. pylori candidate.

Comparative responses of diazotrophic abundance and community structure to the chemical composition of paddy soil.

Diazotrophy is considered as one of the most crucial and dynamic phenomena in the rice field and also a major source of nitrogen input. The objective of this study was to elucidate possible interactions between diverse and dominant diazotrophic bacterial community and organic carbon composition of the paddy soil. Our results suggest that most abundantly found diazotrophs belong to a proteobacteria group and uncultured bacterial forms. A gene abundance study clearly showed significantly higher diazotrophic abundance (P<0.01) at Chandauli (CHN) as compared to Varanasi (VNS) and Ghazipur (GHJ) districts of Eastern Uttar Pradesh, India, with nitrogenase reductase (nifH) copy number between 1.44×103 and 3.34×103copyg-1 soil. Fourier-transform infrared (FT-IR) spectroscopy data identified -CO-, C=O ([Formula: see text] and -NH-), [Formula: see text], and OH- as dominant organic functional groups in the paddy soil. Multivariate analysis was performed to get a clear and more accurate picture of interactions between free-living diazotrophs and abiotic soil factors. Regression analysis suggested a similar trend of distribution of different functional groups along each site. Relative abundance and diversity of diazotrophic population increased in response to FT-IR-based soil organic fractions. Maximum number of FT-IR spectral peak at sites in the Chandauli district augmented its bacterial diazotrophic diversity and abundance. Taken together, the present study sheds light on the substrate-driven composition of the microbial population of selected paddy areas.

Immunogenicity and protective efficacy of multistage vaccine candidates (Mtb8.4-HspX and HspX-Mtb8.4) against Mycobacterium tuberculosis infection in mice

In this study, Mtb8.4 and HspX, which are expressed at proliferating and dormant stages of Mycobacterium tuberculosis (M. tuberculosis), respectively, were chosen to construct two fusion proteins, Mtb8.4-HspX (8.4H) and HspX-Mtb8.4 (H8.4), and we investigated whether the antigen dose and protein sequential order could impact the immunogenicity and protective efficacy of these fusion protein vaccines against M. tuberculosis. C57BL/6 mice were vaccinated with new constructions containing a fusion protein with adjuvant of N, N′-dimethyl-N, N′-dioctadecylammonium bromide (DDA) or a mixed adjuvant composed of DDA, polyribocytidylic acid and gelatin (DPG), and the antigen specific immune responses and protective efficacy against M. tuberculosis H37Rv were evaluated. The results showed that both antigens, Mtb8.4-HspX and HspX-Mtb8.4, could elicit strong human T cell responses. With the existing of DDA adjuvant, HspX-Mtb8.4 induced significantly higher secretion level of IFN-γ and TNF-α in spleen cells than Mtb8.4-HspX (p<0.05). In its protective efficacy study, the isolated bacterial Colony Form Unit (CFU) in H8.4-DPG group was significantly reduced compared to 8.4H–DPG group (p<0.05). Furthermore, with the stimulation of Mtb8.4 in vitro, the secretion of IFN-γ and TNF-α from mice immunized with 20μg of H8.4 exhibited relative higher level than the group immunized by 7μg of H8.4 (p<0.05), whereas, IL-2 secreting showed contrary result. The data suggest that the antigen sequential order and dose selection should be considered when a tuberculosis protein vaccine is to be constructed and its immune strategy is to be planned.

Aerobic carbon monoxide oxidation in the course of growth of a hyperthermophilic archaeon, Sulfolobus sp. ETSY

An aerobic hyperthermophilic CO-oxidizing archaeon, Sulfolobus sp. strain ETSY, was isolated and characterized. Presently, it is the only known representative of both hyperthermophiles and Archaea that is capable of aerobic oxidation of CO, a gas of global importance for atmospheric chemistry and of local importance as one of the substrates for the microbial communities of hydrothermal vents. In the genome of Sulfolobus sp. ETSY we found genetic determinants of aerobic CO oxidation: a coxFMSLDE gene cluster and two separately located coxG genes. We also found such gene clusters in the genomes of certain strains of Sulfolobus islandicus and Sulfolobus solfataricus. On the phylogenetic tree of large subunits of aerobic CO-dehydrogenases (CoxLs), these proteins of Sulfolobus representatives formed a compact cluster within one of the branches formed by bacterial form I CoxLs. Thus we argue that the ability to oxidize CO aerobically was acquired by Sulfolobus ancestor from Bacteria relatively late in the evolution, presumably after the formation of the atmosphere with a high oxygen content.

Determinación molecular de Leptospira spp. en semen y líquido preseminal y estudio serológico de caballos criollos en el departamento de Cundinamarca (Colombia)

El propósito de este estudio fue detectar serológica (prueba de microaglutinación) y molecularmente (el ADN de Leptospira spp. por PCR convencional-reacción de la polimerasa en cadena) la exposición o presencia de Leptospira spp., a partir de muestras de suero sanguíneo, líquido preseminal y semen en caballos reproductores criollos colombianos representativos de esta raza, en 44 criaderos del departamento de Cundinamarca. En Colombia no existen estudios relacionados con la presencia de leptospiras en semen equino, y dentro de los planes sanitarios en esta especie no se vacuna contra esta enfermedad. Se evaluaron muestras de un total de 107 animales, escogidos por muestreo por conveniencia, de las cuales al analizar el suero fueron seroreactivas 35 (32,7 %), correspondientes al serogrupo Leptospira interrogans, serovariedades Canícola, Pomona y Grippotyphosa. Se detectó el DNA de Leptospira spp., por PCR convencional en dos muestras de semen que representaron el 1,9 % del total de muestras. Mediante la técnica de campo oscuro se encontraron en la mayoría de las muestras de líquido preseminal diferentes formas bacterianas, algunas de ellas compatibles con leptospira. También se observaron células de descamación, cristales y uratos. Adicionalmente, no se obtuvo aislamiento de la bacteria en el medio EMJH y no se detectó ADN mediante la técnica de PCR convencional a partir del líquido preseminal.

Intestinal Anti-inflammatory Effects of Outer Membrane Vesicles from Escherichia coli Nissle 1917 in DSS-Experimental Colitis in Mice.

Escherichia coli Nissle 1917 (EcN) is a probiotic strain with proven efficacy in inducing and maintaining remission of ulcerative colitis. However, the microbial factors that mediate these beneficial effects are not fully known. Gram-negative bacteria release outer membrane vesicles (OMVs) as a direct pathway for delivering selected bacterial proteins and active compounds to the host. In fact, vesicles released by gut microbiota are emerging as key players in signaling processes in the intestinal mucosa. In the present study, the dextran sodium sulfate (DSS)-induced colitis mouse model was used to investigate the potential of EcN OMVs to ameliorate mucosal injury and inflammation in the gut. The experimental protocol involved pre-treatment with OMVs for 10 days before DSS intake, and a 5-day recovery period. Oral administration of purified EcN OMVs (5 μg/day) significantly reduced DSS-induced weight loss and ameliorated clinical symptoms and histological scores. OMVs treatment counteracted altered expression of cytokines and markers of intestinal barrier function. This study shows for the first time that EcN OMVs can mediate the anti-inflammatory and barrier protection effects previously reported for this probiotic in experimental colitis. Remarkably, translation of probiotics to human healthcare requires knowledge of the molecular mechanisms involved in probiotic–host interactions. Thus, OMVs, as a non-replicative bacterial form, could be explored as a new probiotic-derived therapeutic approach, with even lower risk of adverse events than probiotic administration.