Unusual Sesquiterpenes from Streptomyces olindensis DAUFPE 5622

In nature, the vast majority of sesquiterpenes are produced by type I mechanisms, and glycosylated sesquiterpenes are rare in actinobacteria. Streptomyces olindensis DAUFPE 5622 produces the sesquiterpenes olindenones A-G, a new class of rearranged drimane sesquiterpenes. Olindenones B-D are oxygenated derivatives of olindenone A, while olindenones E-G are analogs glycosylated with dideoxysugars. 13C-isotope labeling studies demonstrated olindenone A biosynthesis occurs via the methylerythritol phosphate (MEP) pathway and suggested the rearrangement is only partially concerted. Based on the structures, one potential mechanism of olindenone A formation proceeds by cyclization of the linear terpenoid precursor, likely occurring via a terpene cyclase-mediated type II mechanism whereby the terminal alkene of the precursor is protonated, triggering carbocation-driven cyclization followed by rearrangement. Diphosphate hydrolysis may occur either before or after cyclization. Although a biosynthetic route is proposed, the terpene cyclase gene responsible for producing olindenones currently remains unidentified.

An Evaluation of Emergency Medicine Core Content Covered by Podcasts

INTRODUCTION

Podcasts are used broadly for learning in emergency medicine (EM); however, there is concern about the potential for knowledge gaps for learners who rely on podcasts for their learning. The extent to which EM podcasts cover the core curriculum of EM is not known; thus, we sought to quantify the extent to which podcasts represent the core content of our specialty.

METHODS

We performed a retrospective review of all EM podcast episodes published in 2019. All podcasts were given credit for the content they covered as it related to the 2016 American Board of Emergency Medicine (ABEM) Model of Clinical Practice in Emergency Medicine (EM Model). The primary outcome was a description of how podcasts represented the ABEM EM Model content topics compared to the topic representation of the ABEM Qualifying Exam.

RESULTS

We included 54 unique EM podcast programs and 1,193 podcast episodes. They covered 2,965 total EM Model core content topics. The topics most covered were "other" (which includes interpersonal skills and professionalism), procedures, and signs and symptoms. Musculoskeletal, hematology, and environmental each accounted for less than 1% of all topics covered. Almost three-quarters of podcast episodes covered other core competencies of the practice of EM.

CONCLUSION

Podcasts had a broad yet imbalanced coverage of the ABEM EM Model core content subtopics in 2019, with a notable coverage of other core competencies of the practice of EM. Learners, educators, and scholars should be mindful of these gaps and focus future work on exploring how podcasts should best be used in EM education.

Genome mining of Streptomyces sp. BRB081 reveals the production of the antitumor pyrrolobenzodiazepine sibiromycin

Employing a genome mining approach, this work aimed to further explore the secondary metabolism associated genes of Streptomyces sp. BRB081, a marine isolate. The genomic DNA of BRB081 was sequenced and assembled in a synteny-based pipeline for biosynthetic gene clusters (BGCs) annotation. A total of 27 BGCs were annotated, including a sibiromycin complete cluster, a bioactive compound with potent antitumor activity. The production of sibiromycin, a pyrrolobenzodiazepine, was confirmed by the analysis of obtained BRB081 extract by HPLC-MS/MS, which showed the presence of the sibiromycin ions themselves, as well as its imine and methoxylated forms. To verify the presence of this cluster in other genomes available in public databases, a genome neighborhood network (GNN) was constructed with the non-ribosomal peptide synthetase (NRPS) gene from Streptomyces sp. BRB081. Although the literature does not report the occurrence of the sibiromycin BGC in any other microorganism than Streptosporangium sibiricum, we have located this BGC in 10 other genomes besides the BRB081 isolate, all of them belonging to the Actinomycetia class. These findings strengthen the importance of uninterrupted research for new producer strains of secondary metabolites with uncommon biological activities. These results reinforced the accuracy and robustness of genomics in the screening of natural products. Furthermore, the unprecedented nature of this discovery confirms the unknown metabolic potential of the Actinobacteria phylum and the importance of continuing screening studies in this taxon.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03305-0.

Reciprocal transplantation of the heterotrophic coral Tubastraea coccinea (Scleractinia: Dendrophylliidae) between distinct habitats did not alter its venom toxin composition

Tubastraea coccinea is an azooxanthellate coral species recorded in the Indian and Atlantic oceans and is presently widespread in the southwestern Atlantic with an alien status for Brazil. T. coccinea outcompete other native coral species by using a varied repertoire of biological traits. For example, T. coccinea has evolved potent venom capable of immobilizing and digesting zooplankton prey. Diversification and modification of venom toxins can provide potential adaptive benefits to individual fitness, yet acquired alteration of venom composition in cnidarians is poorly understood as the adaptive flexibility affecting toxin composition in these ancient lineages has been largely ignored. We used quantitative high-throughput proteomics to detect changes in toxin expression in clonal fragments of specimens collected and interchanged from two environmentally distinct and geographically separate study sites. Unexpectedly, despite global changes in protein expression, there were no changes in the composition and abundance of toxins from coral fragments recovered from either site, and following clonal transplantation between sites. There were also no apparent changes to the cnidome (cnidae) and gross skeletal or soft tissue morphologies of the specimens. These results suggest that the conserved toxin complexity of T. coccinea co-evolved with innovation of the venom delivery system, and its morphological development and phenotypic expression are not modulated by habitat pressures over short periods of time. The adaptive response of the venom trait to specific predatory regimes, however, necessitates further consideration.

Marine Bacteria from Rocas Atoll as a Rich Source of Pharmacologically Active Compounds

Rocas Atoll is a unique environment in the equatorial Atlantic Ocean, hosting a large number of endemic species, however, studies on the chemical diversity emerging from this biota are rather scarce. Therefore, the present work aims to assess the metabolomic diversity and pharmacological potential of the microbiota from Rocas Atoll. A total of 76 bacteria were isolated and cultured in liquid culture media to obtain crude extracts. About one third (34%) of these extracts were recognized as cytotoxic against human colon adenocarcinoma HCT-116 cell line. 16S rRNA gene sequencing analyses revealed that the bacteria producing cytotoxic extracts were mainly from the Actinobacteria phylum, including Streptomyces, Salinispora, Nocardiopsis, and Brevibacterium genera, and in a smaller proportion from Firmicutes phylum (Bacillus). The search in the spectral library in GNPS (Global Natural Products Social Molecular Networking) unveiled a high chemodiversity being produced by these bacteria, including rifamycins, antimycins, desferrioxamines, ferrioxamines, surfactins, surugamides, staurosporines, and saliniketals, along with several unidentified compounds. Using an original approach, molecular networking successfully highlighted groups of compounds responsible for the cytotoxicity of crude extracts. Application of DEREPLICATOR+ (GNPS) allowed the annotation of macrolide novonestimycin derivatives as the cytotoxic compounds existing in the extracts produced by Streptomyces BRB-298 and BRB-302. Overall, these results highlighted the pharmacological potential of bacteria from this singular atoll.

Venom Composition Does Not Vary Greatly Between Different Nematocyst Types Isolated from the Primary Tentacles of Olindias sambaquiensis (Cnidaria: Hydrozoa)

In this quantitative proteomics study we determined the variety and relative abundance of toxins present in enriched preparations of two nematocyst types isolated from the primary tentacles of the adult medusa stage of the hydrozoan Olindias sambaquiensis. The two nematocyst types were microbasic mastigophores and microbasic euryteles, and these were recovered from the macerated tentacle tissues by using a differential centrifugation approach. Soluble protein extracts from these nematocysts were tagged with tandem mass tag isobaric labels and putative toxins identified using tandem mass spectrometry coupled with a stringent bioinformatics annotation pipeline. Astonishingly, the venom composition of the two capsule types was nearly identical, and there was also little difference in the comparative abundance of toxins between the two nematocyst preparations. This homogeneity suggested that the same toxin complement was present regardless of the penetrative ability of the nematocyst type. Predicted toxin protein families that constituted the venom closely matched those of the toxic proteome of O. sambaquiensis published four years previously, suggesting that venom composition in this species changes little over time. Retaining an array of different nematocyst types to deliver a single venom, rather than sustaining the high metabolic cost necessary to maintain a dynamically evolving venom, may be more advantageous, given the vastly different interspecific interactions that adult medusa encounter in coastal zones.

The biotechnological potential of Epicoccum spp.: diversity of secondary metabolites

Epicoccum is a genus of ubiquitous fungi typically found in air, in soil, and on decaying vegetation. They also commonly display an endophytic lifestyle and are isolated from diverse plant tissues. The fungi from the genus Epicoccum are mainly known for their use as biocontrol agents against phytopathogens and for their ability to produce many secondary metabolites with potential biotechnological applications, such as antioxidant, anticancer,r and antimicrobial compounds. Among the bioactive compounds produced by Epicoccum spp., epicocconone is a commercially available fluorophore, D8646-2-6 is a patented telomerase inhibitor, and taxol is an anticancer drug originally isolated from Taxus brevifolia. Epicoccum spp. also produces epicolactone, an antimicrobial compound with a unique and complex structure that has aroused considerable interest in the chemical-synthesis community. The main goal of the present review is to discuss the diversity of secondary metabolites produced by Epicoccum spp., their biotechnological applications, and proposed hypothetical biosynthesis. In addition, the use of Epicoccum spp. as biocontrol agents and the pigments produced by these fungi are also discussed.

Influence of water quality on diversity and composition of fungal communities in a tropical river

Freshwater fungi are key decomposers of organic material and play important roles in nutrient cycling, bio-remediation and ecosystem functioning. Although aquatic fungal communities respond to pollution, few studies have quantitatively assessed the effect of freshwater contamination on fungal diversity and composition; and knowledge is scarcer for tropical systems. Here we help fill this knowledge gap by studying a heavily-contaminated South American river spanning a biodiversity hotspot. We collected 30 water samples scattered across a quality gradient over two seasons and analyzed them using Terminal Restriction Fragment Length Polymorphisms (T-RFLP) coupled with 454 Pyrosequencing. Using T-RFLP we identified 451 and 442 Operational Taxonomy Units (OTUs) in the dry and rainy seasons respectively, whereas Pyrosequencing revealed 48,553 OTUs from which 11% were shared between seasons. Although 68% of all identified OTUs and 51% of all identified phyla remained unidentified, dominant fungal phyla included the Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Zygomycota and Neocallimastigomycota, while Calcarisporiella, Didymosphaeria, Mycosphaerella (Ascomycota) and Rhodotorula (Basidiomycota) were the most abundant genera. Fungal diversity was affected by pH and dissolved iron, while community composition was influenced by dissolved oxygen, pH, nitrate, biological oxygen demand, total aluminum, total organic carbon, total iron and seasonality. The presence of potentially pathogenic species was associated with high pH. Furthermore, geographic distance was positively associated with community dissimilarity, suggesting that local conditions allowed divergence among fungal communities. Overall, our findings raise potential concerns for human health and the functioning of tropical river ecosystems and they call for improved water sanitation systems.

Corrigendum: Pectins, Endopolygalacturonases, and Bioenergy

[This corrects the article on p. 1401 in vol. 7, PMID: 27703463.].

Comparative proteomics reveals recruitment patterns of some protein families in the venoms of Cnidaria

Cnidarians are probably the oldest group of animals to be venomous, yet our current picture of cnidarian venom evolution is highly imbalanced due to limited taxon sampling. High-throughput tandem mass spectrometry was used to determine venom composition of the scyphozoan Chrysaora lactea and two cubozoans Tamoya haplonema and Chiropsalmus quadrumanus. Protein recruitment patterns were then compared against 5 other cnidarian venom proteomes taken from the literature. A total of 28 putative toxin protein families were identified, many for the first time in Cnidaria. Character mapping analysis revealed that 17 toxin protein families with predominantly cytolytic biological activities were likely recruited into the cnidarian venom proteome before the lineage split between Anthozoa and Medusozoa. Thereafter, venoms of Medusozoa and Anthozoa differed during subsequent divergence of cnidarian classes. Recruitment and loss of toxin protein families did not correlate with accepted phylogenetic patterns of Cnidaria. Selective pressures that drive toxin diversification independent of taxonomic positioning have yet to be identified in Cnidaria and now warrant experimental consideration.

Pectins, Endopolygalacturonases, and Bioenergy

The precise disassembly of the extracellular matrix of some plant species used as feedstocks for bioenergy production continues to be a major barrier to reach reasonable cost effective bioethanol production. One solution has been the use of pretreatments, which can be effective, but increase even more the cost of processing and also lead to loss of cell wall materials that could otherwise be used in industry. Although pectins are known to account for a relatively low proportion of walls of grasses, their role in recalcitrance to hydrolysis has been shown to be important. In this mini-review, we examine the importance of pectins for cell wall hydrolysis highlighting the work associated with bioenergy. Here we focus on the importance of endopolygalacturonases (EPGs) discovered to date. The EPGs cataloged by CAZy were screened, revealing that most sequences, as well as the scarce structural work performed with EPGs, are from fungi (mostly Aspergillus niger). The comparisons among the EPG from different microorganisms, suggests that EPGs from bacteria and grasses display higher similarity than each of them with fungi. This compilation strongly suggests that structural and functional studies of EPGs, mainly from plants and bacteria, should be a priority of research regarding the use of pectinases for bioenergy production purposes.

Chromobacterium violaceum adaptation to low-phosphate conditions

Chromobacterium violaceum is a free-living bacterium that inhabits low-nutrient environments such as the Amazon basin. Bacteria respond to phosphate (Pi) shortage by expressing a range of genes involved in Pi uptake and assimilation, known as the PHO regulon. Several PHO regulon genes have been annotated in the genome of C. violaceum. Here we show that C. violaceum is extremely well adapted to low-Pi conditions. Remarkably, this bacterium is able to grow in media containing only traces of Pi. The PHO regulon genes are induced upon Pi depletion, but the bacteria continued to grow under these conditions. Unlike other Proteobacteria hitherto analyzed, neither PstS nor PhoU play a role in the repression of the PHO regulon under Pi excess.

Enhancing of sugar cane bagasse hydrolysis by Annulohypoxylon stygium glycohydrolases

The aim of this study was to develop a bioprocess for the production of β-glucosidase and pectinase from the fungus Annulohypoxylon stygium DR47. Media optimization and bioreactor cultivation using citrus bagasse and soybean bran were explored and revealed a maximum production of 6.26 U/mL of pectinase at pH 4.0 and 10.13 U/mL of β-glucosidase at pH 5.0. In addition, the enzymes extracts were able to replace partially Celluclast 1.5L in sugar cane bagasse hydrolysis. Proteomic analysis from A. stygium cultures revealed accessory enzymes, mainly belong to the families GH3 and GH54, that would support enhancement of commercial cocktail saccharification yields. This is the first report describing bioreactor optimization for enzyme production from A. stygium with a view for more efficient degradation of sugar cane bagasse.

Tight control of light beams in photonic crystals with spatially-variant lattice orientation

Spatially-variant photonic crystals (SVPCs), in which the orientation of the unit cell changes as a function of position, are shown to be capable of abruptly controlling light beams using just low index materials and can be made to have high polarization selectivity. Multi-photon direct laser writing in the photo-polymer SU-8 was used to fabricate three-dimensional SVPCs that direct the flow of light around a 90 degree bend. The lattice spacing and fill factor were maintained nearly constant throughout the structure. The SVPCs were characterized at a wavelength of 2.94 μm by scanning the faces with optical fibers and the results were compared to electromagnetic simulations. The lattices were shown to direct infrared light of one polarization through sharp bends while the other polarization propagated straight through the SVPC. This work introduces a new scheme for controlling light that should be useful for integrated photonics.

Screening bacterial metabolites for inhibitory effects against Batrachochytrium dendrobatidis using a spectrophotometric assay

Certain bacteria present on frog skin can prevent infection by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), conferring disease resistance. Previous studies have used agar-based in vitro challenge assays to screen bacteria for Bd-inhibitory activity and to identify candidates for bacterial supplementation trials. However, agar-based assays can be difficult to set up and to replicate reliably. To overcome these difficulties, we developed a semi-quantitative spectrophotometric challenge assay technique. Cell-free supernatants were prepared from filtered bacterial cultures and added to 96-well plates in replicated wells containing Bd zoospores suspended in tryptone-gelatin hydrolysate-lactose (TGhL) broth medium. Plates were then read daily on a spectrophotometer until positive controls reached maximum growth in order to determine growth curves for Bd. We tested the technique by screening skin bacteria from the Australian green-eyed tree frog Litoria serrata. Of bacteria tested, 31% showed some degree of Bd inhibition, while some may have promoted Bd growth, a previously unknown effect. Our cell-free supernatant challenge assay technique is an effective in vitro method for screening bacterial isolates for strong Bd-inhibitory activity. It contributes to the expanding field of bioaugmentation research, which could play a significant role in mitigating the effects of chytridiomycosis on amphibians around the world.

The diversity of polyketide synthase genes from sugarcane-derived fungi

The chemical ecology and biotechnological potential of metabolites from endophytic and rhizosphere fungi are receiving much attention. A collection of 17 sugarcane-derived fungi were identified and assessed by PCR for the presence of polyketide synthase (PKS) genes. The fungi were all various genera of ascomycetes, the genomes of which encoded 36 putative PKS sequences, 26 shared sequence homology with β-ketoacyl synthase domains, while 10 sequences showed homology to known fungal C-methyltransferase domains. A neighbour-joining phylogenetic analysis of the translated sequences could group the domains into previously established chemistry-based clades that represented non-reducing, partially reducing and highly reducing fungal PKSs. We observed that, in many cases, the membership of each clade also reflected the taxonomy of the fungal isolates. The functional assignment of the domains was further confirmed by in silico secondary and tertiary protein structure predictions. This genome mining study reveals, for the first time, the genetic potential of specific taxonomic groups of sugarcane-derived fungi to produce specific types of polyketides. Future work will focus on isolating these compounds with a view to understanding their chemical ecology and likely biotechnological potential.

Molecular phylogeny of Burkholderia pseudomallei from a remote region of Papua New Guinea

Background

The island of New Guinea is located midway between the world's two major melioidosis endemic regions of Australia and Southeast Asia. Previous studies in Papua New Guinea have demonstrated autochthonous melioidosis in Balimo, Western province. In contrast to other regions of endemicity, isolates recovered from both environmental and clinical sources demonstrate narrow genetic diversity over large spatial and temporal scales.

Methodology/Principal Findings

We employed molecular typing techniques to determine the phylogenetic relationships of these isolates to each other and to others worldwide to aid in understanding the origins of the Papua New Guinean isolates. Multi-locus sequence typing of the 39 isolates resolved three unique sequence types. Phylogenetic reconstruction and Structure analysis determined that all isolates were genetically closer to those from Australia than those from Southeast Asia. Gene cluster analysis however, identified a Yersinia-like fimbrial gene cluster predominantly found among Burkholderia pseudomallei derived from Southeast Asia. Higher resolution VNTR typing and phylogenetic reconstruction of the Balimo isolates resolved 24 genotypes with long branch lengths. These findings are congruent with long term persistence in the region and a high level of environmental stability.

Conclusions/Significance

Given that anthropogenic influence has been hypothesized as a mechanism for the dispersal of B. pseudomallei, these findings correlate with limited movement of the indigenous people in the region. The palaeogeographical and anthropogenic history of Australasia and the results from this study indicate that New Guinea is an important region for the further study of B. pseudomallei origins and dissemination.

Polyhydroxyalkanoates production by actinobacteria isolated from soil

Polyhydroxyalkanoates (PHAs) are biodegradable and renewable polymers produced by a wide range of bacterial groups. New microbial bioprospection approaches have become an important way to find new PHA producers and new synthesized polymers. Over the past years, bacteria belonging to actinomycetes group have become known as PHA producers, such as Nocardia and Rhodococcus species, Kineosphaera limosa Liu et al. 2002, and, more recently, Streptomyces species. In this paper, we disclose that there are more actinobacteria PHA producers in addition to the genera cited. Some unusual genera, such as Streptoalloteichus, and some genera frequently present in soil, such as Streptacidiphilus, have been found. Thirty-four isolates were able to accumulate poly(3-hydroxybutyrate) and a number of these have traces of poly(3-hydroxyvalerate) when cultivated on glucose or glucose and casein as carbon source. Furthermore, some strains showed traces of medium chain length PHA. Transmission electron microscopy demonstrated that the PHA accumulation occurs in hyphae and spores.

Incidence of the major Brassica pests in northwestern Spain

Kale (Brassica oleracea L. acephala group) crops are common in northwestern Spain, where they are severely damaged by different insect pests. The damage notably affects the value of this crop because it is freshly consumed and fresh processed. The objective of this work was to determine the abundance and relative importance of the main Lepidoptera pests of Brassica crops for 6 yr at five localities in northwestern Spain and to relate the seasonal changes of larval populations and environmental conditions. Pheromone traps were used as a method of monitoring adults. Larval populations were monitored on kales by counting the larvae for several years and locations at different sample dates. Five species were found: Mamestra brassicae (L.); imported cabbageworm, Pieris rapae (L.); Pieris brassicae (L.); diamondback moth, Plutella xyllostella (L.); and Autographa gamma L. Proportions of each insect fluctuated over the years and in the different locations. M. brassicae was the most abundant (48.5% of the total of Lepidoptera species) followed by P. xyllostella (25%) and P. rapae (15%). The use of pheromone traps combined with plant sampling permitted the detection of two generations of M. brassicae. However, adult counts were not correlated to the number of larvae on plants.

Characterisation of anthracyclines from a cosmomycin D-producing species of Streptomyces by collisionally-activated dissociation and ion mobility mass spectrometry

Cultures of cosmomycin D-producing Streptomyces olindensis ICB20 that were propagated for many generations underwent mutations that resulted in production of a range of related anthracyclines by the bacteria. The anthracyclines that retained the two trisaccharide chains of the parent compound were separated by HPLC. Exact mass determination of these compounds revealed that they differed from cosmomycin D (CosD) in that they contained one to three fewer oxygen atoms (loss of hydroxyl groups). Some of the anthracyclines that were separated by HPLC had the same mass. The location from which the hydroxyl groups had been lost relative to CosD (on the aglycone and/or on the sugar residues) was probed by collisionally-activated dissociation using an electrospray ionisation linear quadrupole ion trap mass spectrometer. The presence of anthracyclines with the same mass, but different structure, was confirmed using an electrospray ionisation travelling wave ion mobility mass spectrometer.

Comparative transcriptome analysis of Listeria monocytogenes strains of the two major lineages reveals differences in virulence, cell wall, and stress response

Listeria monocytogenes is a food-borne, opportunistic, bacterial pathogen causing a wide spectrum of diseases, including meningitis, septicemia, abortion, and gastroenteritis, in humans and animals. Among the 13 L. monocytogenes serovars described, human listeriosis is mostly associated with strains of serovars 4b, 1/2b, and 1/2a. Within the species L. monocytogenes, three phylogenetic lineages are described. Serovar 1/2a belongs to phylogenetic lineage I, while serovars 4b and 1/2b group in phylogenetic lineage II. To explore the role of gene expression in the adaptation of L. monocytogenes strains of these two major lineages to different environments, as well as in virulence, we performed whole-genome expression profiling of six L. monocytogenes isolates of serovars 4b, 1/2b, and 1/2a of distinct origins, using a newly constructed Listeria multigenome DNA array. Comparison of the global gene expression profiles revealed differences among strains. The expression profiles of two strains having distinct 50% lethal doses, as assessed in the mouse model, were further analyzed. Gene ontology term enrichment analysis of the differentially expressed genes identified differences in protein-, nucleic acid-, carbon metabolism-, and virulence-related gene expression. Comparison of the expression profiles of the core genomes of all strains revealed differences between the two lineages with respect to cell wall synthesis, the stress-related sigma B regulon and virulence-related genes. These findings suggest different patterns of interaction with host cells and the environment, key factors for host colonization and survival in the environment.

Insights in the glycosylation steps during biosynthesis of the antitumor anthracycline cosmomycin: characterization of two glycosyltransferase genes

Glycosylation pattern in cosmomycins is a distinctive feature among anthracyclines. These antitumor compounds possess two trisaccharide chains attached at C-7 and C-10, each of them with structural variability, mainly at the distal deoxysugar moieties. We have characterized a 14-kb chromosomal region from Streptomyces olindensis containing 13 genes involved in cosmomycin biosynthesis. Two of the genes, cosG and cosK, coding for glycosyltransferase were inactivated with the generation of five new derivatives. Structural elucidation of these compounds showed altered glycosylation patterns indicating the capability of both glycosyltransferases of transferring deoxysugars to both sides of the aglycone and the flexibility of CosK with respect to the deoxysugar donor. A model is proposed for the glycosylation steps during cosmomycins biosynthesis.

Plasmid-related beta-lactamase production in Bacteroides fragilis strains

Twenty Bacteroides fragilis group species isolated from children with and without diarrhea were analyzed. Antibiotic susceptibility was performed using an agar dilution method; beta-lactamase production was determined using a nitrocefin method, and plasmids were extracted using a commercial Miniprep System. MIC values ranged from 16 to 256 microg/ml for penicillin, 4-128 microg/ml for amoxicillin/clavulanic acid, 0.25-256 microg/ml for clindamycin, and 16-256 microg/ml for penicillin. beta-Lactamase was detected in all isolates. Only five isolates harbored plasmids varying from 7.8 to 1.8 kb. Loss of 6.4- and 3.8-kb plasmids in B. fragilis C68c was related to antibiotic resistance. Low molecular weight plasmids of 2.8-1.8 kb were stable. PCR amplification of cfiA and cepA genes was observed using total DNA, and the cfiA gene was also amplified from the 6.4-kb plasmid.

Effect of pH on the production of the antitumor antibiotic retamycin by Streptomyces olindensis

The effect of pH on cell growth and retamycin production in batch bioreactor cultures of Streptomyces olindensis ICB20 was investigated. In fermentations pH-controlled over the range 6.0-8.0, the highest retamycin production was achieved at pH 7.0, and the maximum concentration of retamycin, about 1.36 A (absorbance) units, was about 43, 58 and 232% higher than the values obtained at pH 7.5, 6.0 and 8.0 respectively.

DNA-binding properties of cosmomycin D, an anthracycline with two trisaccharide chains

Cosmomycin D (CosD) is the major constituent fraction isolated from a culture of Streptomyces olindensis ICB20. The ability of this compound to intercalate with double-stranded DNA was studied by gel mobility shift assays and electrospray ionization mass spectrometry (ESI-MS). ESI-MS experiments showed that the complex of CosD with 16-mer double-stranded DNA was at least as stable as a complex of daunorubicin with the same DNA sequence. This is the first study showing DNA binding properties of an anthracycline containing a beta-rhodomycinone aglycone chromophore O-linked to two trisaccharide chains.

Phenotypic stability and plasmid detection in Actinobacillus actinomycetemcomitans

The stability of hemolytic activity, antibiotic resistance and plasmid detection in Actinobacillus actinomycetemcomitans isolates were studied. These characteristics were stable for all experimental conditions. All tested isolates lost or changed some phenotypic characteristics such as colonial morphology and growth in liquid medium.

Intervención educativa comunitaria sobre la diabetes en el ámbito de la atención primaria

OBJECTIVE

To offer an educational alternative on diabetes, with the participation of patients with type 2 diabetes, their family members, and health care providers, adapted to local conditions and to these person's felt needs.

METHODS

Focused on the primary-care level, this program was carried out in the health area of El Guarco, which is in the province of Cartago, Costa Rica. The first stage of the project included a qualitative study of the knowledge and practices of both patients and health care providers, looking at diabetes prevention and control and the local availability of foods. Based on those results, an educational methodology was developed, educational manuals were written, and courses for health care providers, patients, and patients' families were implemented. Other strategies were developed to make the effort sustainable.

RESULTS

We found that patients did not associate family history or obesity with diabetes and that those persons were also confused about the symptoms of diabetes. Patients also received inconsistent nutrition messages from health care providers. Using the diabetes education manual as a base, the providers increased their knowledge of diabetes prevention, treatment, and education by an average of 85%. The diabetic patients who received educational training (mean age, 57.0 years, with a standard deviation of 8.9 years; 92% women) improved their glycemic control. Blood glucose levels decreased from 189 +/- 79 mg/dL (average and standard deviation) to 157 +/- 48 mg/dL (P < 0.05), and glycosylated hemoglobin (HbA1c) went from 11.3% +/- 2.4% to 9.7% +/- 2.3% (P = 0.05). There were no significant changes in body weight or lipid profile, except for triglycerides, which declined (P < 0.05).

CONCLUSIONS

This educational program was successfully incorporated into the regular activities of the El Guarco-area health centers. The primary-care level is ideal for carrying out educational programs for diabetes treatment and early detection that are directed at patients, their families, and health care providers.

Quality of life in patients with heart failure: do gender differences exist?

OBJECTIVE

The purpose of this study was to evaluate gender differences in quality of life (QOL) in a large sample of age-matched and ejection fraction (EF)-matched patients with heart failure.

DESIGN

Matched comparisons of secondary data were used.

SETTING

The setting consisted of multicenter Studies of Left Ventricular Dysfunction trials.

SAMPLE

The sample included 1382 patients (691 men and 691 women) who were age-matched and EF-matched.

OUTCOME MEASURES

Global QOL and the QOL dimensions of physical function, emotional distress, social health, and general health were measured using the Ladder of Life, items from the Profile of Mood States Inventory, the Functional Status Questionnaire, the beta-Blocker Heart Attack Trial instrument, and an item from the RAND Medical Outcomes Study instrument.

RESULTS

Women had significantly worse general life satisfaction, physical function, and social and general health scores than men. There were no significant differences found between gender groups for current life situation or emotional distress. After controlling for New York Heart Association classification, women still had significantly worse ratings for intermediate activities of daily living (a sub-dimension of physical functioning) and social activity.

CONCLUSIONS

Despite controlling for age, EF, and New York Heart Association classification, women had worse QOL ratings than did men for intermediate activities of daily living and social activity. Research should focus on identifying why differences exist and developing measures to improve QOL, particularly physical functioning, in women with heart failure.

Isolation and cloning of Streptomyces terminal fragments

Streptomyces species have a linear chromosome of approximately 8 Mb in size. Many strains also carry linear plasmids. Most of these linear elements contain terminal proteins covalently bound to the 5' ends of the DNA. Using a method for the visualisation of terminal DNA fragments in agarose gels, it was possible to see three fragments in S. rimosus and five fragments in S. avermitilis. The method was also used to clone the 298 bp BamHI fragment carrying the left end of plasmid SLP2. Analysis of the sequence showed that the end resembled other Streptomyces chromosome and plasmid ends, but there were eight palindromes (instead of seven) and a tandem duplication of a 14 bp sequence.

Altered expression of oligopeptide-binding protein (OppA) and aminoglycoside resistance in laboratory and clinical Escherichia coli strains

Oligopeptide-binding protein (OppA) is the periplasmic component of the major oligopeptide transport system of enteric bacteria. Genetic and biochemical evidence suggests that OppA plays a role in the uptake of aminoglycoside antibiotics in Escherichia coli K-12. Forty-six (82%) of 56 aminoglycoside-resistant mutants of E. coli K-12 selected in vitro had reduced or undetectable OppA levels, as compared with their parent strain. Moreover, nine (36%) of 25 aminoglycoside-resistant clinical isolates of E. coli expressed reduced or undetectable levels of OppA. No decrease in OppA expression was observed among aminoglycoside-sensitive E. coli strains from patients. Twenty-three (42%) of 56 aminoglycoside-resistant mutants of E. coli K-12 and six (24%) of 25 clinical isolates also were deficient for expression of ornithine or arginine decarboxylases, or both, and these deficiencies might negatively affect OppA expression by reducing polyamine synthesis. These results support the view that reduced OppA expression is associated with aminoglycoside resistance in E. coli strains.

The effect of transport on the rate of severe intraventricular hemorrhage in very low birth weight infants

OBJECTIVE

To determine the incidence of grade III or IV intraventricular hemorrhage in very low birth weight (VLBW) infants born at level I hospitals and transported to one tertiary center compared with those delivered at the same level III facility.

METHODS

We evaluated all newborns admitted to a large tertiary neonatal intensive care unit from June 1, 1992, through December 31, 1995. All live born infants with birth weights of 500-1200 g and at least 24 weeks' gestation were included. Neonatal transports within 24 hours of delivery from 11 level I facilities were compared with those delivered at the same level III center with respect to grade III and IV intraventricular hemorrhage. Various antenatal and neonatal data were collected.

RESULTS

Thirty-seven newborns (11%) experienced grade III or IV intraventricular hemorrhages among 329 who met study criteria. There were 27 cases (9%) in the 285 inborn neonates compared with 10 of 44 outborn cases (23%) (P < .02, 95% confidence interval 0.15, 0.87). The mean gestational age of the neonates with grade III or IV intraventricular hemorrhages was significantly lower in the inborn group, which further emphasizes the finding. No other study factors explained the difference.

CONCLUSION

We found a higher risk for grade III or IV intraventricular hemorrhage developing in VLBW infants born at level I hospitals and transported to the tertiary care center compared with those born at the level III facility. This data should be considered when analyzing the potential effects of perinatal deregionalization.

Quality of life in women with symptomatic HIV/AIDS

Despite the increasing incidence of cases of human immune deficiency virus (HIV) infection and of acquired immune deficiency syndrome (AIDS) in women, there is a serious lack of information about those women's quality of life (QoL). The purpose of this exploratory descriptive study was to describe QoL using an HIV-specific instrument (the HOPES) every 2 months over a 4-month period in a convenience sample of 44 women with symptomatic HIV/AIDS. Changes in physical, psychological, social, sexual dimensions, and overall QoL were evaluated along with the frequency of the most prevalent distressing items. The mean scores of the global QoL, physical and psycho-social summary scales were significantly different over the 4-month data collection period: quality of life improved. The most prevalent disruptions were in the psycho-social domain, including financial problems, worry about the family, distress about losing others from HIV, and worry about disease progression. The most prevalent physical disruptions included reduction in energy, difficulties with daily activities and frequent pain. Married women appeared to be more vulnerable to disruptions in QoL over time. In addition to the use of conventional disease-specific parameters for the ongoing follow-up of women with HIV/AIDS, the systematic use of a QoL assessment can provide a focused approach to monitoring problems and targeting interventions. Such an approach is especially important for nurses who assist women living with the symptoms of HIV/AIDS.

Potential consequences of widespread antepartal use of ampicillin

OBJECTIVE

Recommendations for the use of antenatal antibiotics in obstetrics have increased in the past few years, especially for prophylaxis against group B streptococci, for prolongation of the latency time in patients with preterm premature rupture of the membranes, and as an adjuvant treatment in preterm labor. Our objective was to determine whether the use of antenatal ampicillin affects the incidence of and resistance of early-onset neonatal sepsis with organisms other than group B streptococci.

STUDY DESIGN

A prospective cohort study was performed between January 1, 1991, and December 31, 1996. Every case of blood culture-proven neonatal sepsis was prospectively surveyed. The type of bacteria isolated, drug resistance, antenatal antibiotic use and treatment indication, gestational age at delivery, and other antenatal and outcome variables were gathered. Early-onset neonatal sepsis was defined as disease onset within 7 days after birth.

RESULTS

A total of 42 cases of early-onset neonatal sepsis among 29,897 neonates delivered were found during the 6-year period. Of these, 15 cases were due to group B streptococci and 27 were the result of non-group B streptococcal organisms (21 gram-negative rods and 6 gram-positive cocci). Among the 27 non-group B streptococcal cases, 15 mothers had received antenatal ampicillin and 13 of the 15 bacterial isolates from these neonates (87%) were resistant to ampicillin, versus only 2 ampicillin-resistant isolates (17%) among the 12 cases in which no antenatal antibiotics were administered (P = .0004). Of the 15 mothers who were treated with ampicillin, 13 received more than 1 dose. In evaluating each year of the study, the overall administration of antibiotics to pregnant women in the antenatal period increased from <10% in 1991 to 16.9% in 1996. The incidence of early-onset neonatal sepsis with group B streptococci decreased during this time, whereas the incidence of early-onset sepsis with non-group B streptococcal organisms, especially Escherichia coli, increased.

CONCLUSIONS

The increased administration of antenatal ampicillin to pregnant women may be responsible for the increased incidence of early-onset neonatal sepsis with non-group B streptococcal organisms that are resistant to ampicillin. At this time penicillin G, rather than ampicillin, is therefore recommended for prophylaxis against group B streptococci. In addition, future studies are needed to determine whether alternate approaches, such as immunotherapy or vaginal washing, could be of benefit.

Developing a team for multicultural, multi-institutional research on fatigue and quality of life

PURPOSE/OBJECTIVES

To describe the process of establishing a multisite team to conduct research with a multicultural focus on fatigue.

DATA SOURCES

Articles, book chapters, personal experience.

DATA SYNTHESIS

Teamwork facilitated development of a productive professional working group, sharing of resources, and data collection culminating in a research proposal for studying cancer-related fatigue in a multicultural population.

CONCLUSIONS

Establishing a common goal by investing time, committing to the process, and establishing trust was the secret to effective team functioning.

IMPLICATIONS FOR NURSING PRACTICE

The prospect of multi-institutional collaboration has implications for oncology nurses in the areas of research and practice. Goals that could not be achieved easily in the setting of a single institution are reached more easily with multisite collaboration and teamwork.