Effects of Baffles on the Performance of Anerobic Waste Stabilization Ponds

The performance of three baffled model ponds was monitored and compared to the performance of an unbaffled model pond utilizing four hydraulic and organic loading rates. All four ponds were operated simultaneously under the same environmental conditions using a synthetic wastewater. Removal of organic carbon by the biological system in the different pond configurations only varied from 94-98 percent at the longest detention time (15 days); however, a considerable effect of the baffling was observed at the lower detention times. At a hydraulic detention time of 1.5 days the percent carbon removal was 53, 60, 62, and 70 percent for the control, end-around, over-and-under, and longitudinal baffling systems, respectively. The biological kinetics of the model ponds were determined using three mathematical models. Performance was evaluated by using the kinetic parameters and conventional stabilization pond operating parameters. Direct comparisons with the performance parameters of the model ponds appear valid for analysis of the three models studied. The performance of the baffled ponds was described by a completely mixed model incorporating attached biomass; however, the performance of the unbaffled control pond was not described by the completely mixed model. Performance parameters of the baffled, model ponds were significantly better than the control pond

Diversity and Distribution of Borrelia hermsii

Multilocus sequence analysis and laboratory experiments suggest that birds may play a role in maintaining and dispersing this pathogen

Profiling invasive Plasmodium falciparum merozoites using an integrated omics approach

The symptoms of malaria are brought about by blood-stage parasites, which are established when merozoites invade human erythrocytes. Our understanding of the molecular events that underpin erythrocyte invasion remains hampered by the short-period of time that merozoites are invasive. To address this challenge, a Plasmodium falciparum gamma-irradiated long-lived merozoite (LLM) line was developed and investigated. Purified LLMs invaded erythrocytes by an increase of 10–300 fold compared to wild-type (WT) merozoites. Using an integrated omics approach, we investigated the basis for the phenotypic difference. Only a few single nucleotide polymorphisms within the P. falciparum genome were identified and only marginal differences were observed in the merozoite transcriptomes. By contrast, using label-free quantitative mass-spectrometry, a significant change in protein abundance was noted, of which 200 were proteins of unknown function. We determined the relative molar abundance of over 1100 proteins in LLMs and further characterized the major merozoite surface protein complex. A unique processed MSP1 intermediate was identified in LLM but not observed in WT suggesting that delayed processing may be important for the observed phenotype. This integrated approach has demonstrated the significant role of the merozoite proteome during erythrocyte invasion, while identifying numerous unknown proteins likely to be involved in invasion

The Giardia lamblia vsp gene repertoire: characteristics, genomic organization, and evolution

BACKGROUND:Giardia lamblia trophozoites colonize the intestines of susceptible mammals and cause diarrhea, which can be prolonged despite an intestinal immune response. The variable expression of the variant-specific surface protein (VSP) genes may contribute to this prolonged infection. Only one is expressed at a time, and switching expression from one gene to another occurs by an epigenetic mechanism.RESULTS:The WB Giardia isolate has been sequenced at 10x coverage and assembled into 306 contigs as large as 870 kb in size. We have used this assembly to evaluate the genomic organization and evolution of the vsp repertoire. We have identified 228 complete and 75 partial vsp gene sequences for an estimated repertoire of 270 to 303, making up about 4% of the genome. The vsp gene diversity includes 30 genes containing tandem repeats, and 14 vsp pairs of identical genes present in either head to head or tail to tail configurations (designated as inverted pairs), where the two genes are separated by 2 to 4 kb of non-coding DNA. Interestingly, over half the total vsp repertoire is present in the form of linear gene arrays that can contain up to 10 vsp gene members. Lastly, evidence for recombination within and across minor clades of vsp genes is provided.CONCLUSIONS:The data we present here is the first comprehensive analysis of the vsp gene family from the Genotype A1 WB isolate with an emphasis on vsp characterization, function, evolution and contributions to pathogenesis of this important pathogen.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

Systems-Based Analysis of the \u3cem\u3eSarcocystis neurona\u3c/em\u3e Genome Identifies Pathways That Contribute to a Heteroxenous Life Cycle

Sarcocystis neurona is a member of the coccidia, a clade of single-celled parasites of medical and veterinary importance including Eimeria, Sarcocystis, Neospora, and Toxoplasma. Unlike Eimeria, a single-host enteric pathogen, Sarcocystis, Neospora, and Toxoplasma are two-host parasites that infect and produce infectious tissue cysts in a wide range of intermediate hosts. As a genus, Sarcocystis is one of the most successful protozoan parasites; all vertebrates, including birds, reptiles, fish, and mammals are hosts to at least one Sarcocystis species. Here we sequenced Sarcocystis neurona, the causal agent of fatal equine protozoal myeloencephalitis. The S. neurona genome is 127 Mbp, more than twice the size of other sequenced coccidian genomes. Comparative analyses identified conservation of the invasion machinery among the coccidia. However, many dense-granule and rhoptry kinase genes, responsible for altering host effector pathways in Toxoplasma and Neospora, are absent from S. neurona. Further, S. neurona has a divergent repertoire of SRS proteins, previously implicated in tissue cyst formation in Toxoplasma. Systems-based analyses identified a series of metabolic innovations, including the ability to exploit alternative sources of energy. Finally, we present an S. neurona model detailing conserved molecular innovations that promote the transition from a purely enteric lifestyle (Eimeria) to a heteroxenous parasite capable of infecting a wide range of intermediate hosts. IMPORTANCE Sarcocystis neurona is a member of the coccidia, a clade of single-celled apicomplexan parasites responsible for major economic and health care burdens worldwide. A cousin of Plasmodium, Cryptosporidium, Theileria, and Eimeria, Sarcocystis is one of the most successful parasite genera; it is capable of infecting all vertebrates (fish, reptiles, birds, and mammals—including humans). The past decade has witnessed an increasing number of human outbreaks of clinical significance associated with acute sarcocystosis. Among Sarcocystis species, S. neurona has a wide host range and causes fatal encephalitis in horses, marine mammals, and several other mammals. To provide insights into the transition from a purely enteric parasite (e.g., Eimeria) to one that forms tissue cysts (Toxoplasma), we present the first genome sequence of S. neurona. Comparisons with other coccidian genomes highlight the molecular innovations that drive its distinct life cycle strategies

Characteristics of 263K Scrapie Agent in Multiple Hamster Species

Characteristics correlated better with host factors than with agent strain

HIV subtype is not associated with dementia among individuals with moderate and advanced immunosuppression in Kampala, Uganda

HIV-associated neurocognitive disorders (HAND) are a common neurological manifestation of HIV infection. A previous study suggested that HIV dementia may be more common among patients with subtype D virus than among those with subtype A virus among HIV+ individuals with advanced immunosuppression. We conducted a study to evaluate the frequency of HIV dementia, and the association of HIV dementia with HIV subtype and compartmentalization among HIV+ individuals with moderate and advanced immunosuppression (CD4 lymphocyte count >150 cells/μL and < 250 cells/μL)

miR-182 and miR-10a Are Key Regulators of Treg Specialisation and Stability during Schistosome and Leishmania-associated Inflammation

A diverse suite of effector immune responses provide protection against various pathogens. However, the array of effector responses must be immunologically regulated to limit pathogen- and immune-associated damage. CD4+Foxp3+ regulatory T cells (Treg) calibrate immune responses; however, how Treg cells adapt to control different effector responses is unclear. To investigate the molecular mechanism of Treg diversity we used whole genome expression profiling and next generation small RNA sequencing of Treg cells isolated from type-1 or type-2 inflamed tissue following Leishmania major or Schistosoma mansoni infection, respectively. In-silico analyses identified two miRNA “regulatory hubs” miR-10a and miR-182 as critical miRNAs in Th1- or Th2-associated Treg cells, respectively. Functionally and mechanistically, in-vitro and in-vivo systems identified that an IL-12/IFNγ axis regulated miR-10a and its putative transcription factor, Creb. Importantly, reduced miR-10a in Th1-associated Treg cells was critical for Treg function and controlled a suite of genes preventing IFNγ production. In contrast, IL-4 regulated miR-182 and cMaf in Th2-associed Treg cells, which mitigated IL-2 secretion, in part through repression of IL2-promoting genes. Together, this study indicates that CD4+Foxp3+ cells can be shaped by local environmental factors, which orchestrate distinct miRNA pathways preserving Treg stability and suppressor function

Treatment as Prevention: Characterization of Partner Infections in the HIV Prevention Trials Network 052 Trial

HIV Prevention Trials Network (HPTN) 052 demonstrated that antiretroviral therapy (ART) prevents HIV transmission in serodiscordant couples. HIV from index-partner pairs was analyzed to determine the genetic linkage status of partner infections. Forty-six infections were classified as linked, indicating that the index was the likely source of the partner’s infection. Lack of viral suppression and higher index viral load were associated with linked infection. Eight linked infections were diagnosed after the index started ART: four near the time of ART initiation and four after ART failure. Linked infections were not observed when the index participant was stably suppressed on ART

Simultaneous Host-Pathogen Transcriptome Analysis during Granulibacter bethesdensis Infection of Neutrophils from Healthy Subjects and Patients with Chronic Granulomatous Disease

Polymorphonuclear leukocytes (PMN) from patients with chronic granulomatous disease (CGD) fail to produce microbicidal concentrations of reactive oxygen species (ROS) due to mutations in NOX2. Patients with CGD suffer from severe, life-threatening infections and inflammatory complications. Granulibacter bethesdensis is an emerging Gram-negative pathogen in CGD that resists killing by PMN of CGD patients (CGD PMN) and inhibits PMN apoptosis through unknown mechanisms. Microarray analysis was used to study mRNA expression in PMN from healthy subjects (normal PMN) and CGD PMN during incubation with G. bethesdensis and, simultaneously, in G. bethesdensis with normal and CGD PMN. We detected upregulation of antiapoptotic genes (e.g., XIAP and GADD45B) and downregulation of proapoptotic genes (e.g., CASP8 and APAF1) in infected PMN. Transcript and protein levels of inflammation- and immunity-related genes were also altered. Upon interaction with PMN, G. bethesdensis altered the expression of ROS resistance genes in the presence of normal but not CGD PMN. Levels of bacterial stress response genes, including the ClpB gene, increased during phagocytosis by both normal and CGD PMN demonstrating responses to oxygen-independent PMN antimicrobial systems. Antisense knockdown demonstrated that ClpB is dispensable for extracellular growth but is essential for bacterial resistance to both normal and CGD PMN. Metabolic adaptation of Granulibacter growth in PMN included the upregulation of pyruvate dehydrogenase. Pharmacological inhibition of pyruvate dehydrogenase by triphenylbismuthdichloride was lethal to Granulibacter. This study expands knowledge of microbial pathogenesis of Granulibacter in cells from permissive (CGD) and nonpermissive (normal) hosts and identifies potentially druggable microbial factors, such as pyruvate dehydrogenase and ClpB, to help combat this antibiotic-resistant pathogen.This is the publisher’s final pdf. The published article is copyrighted by American Society for Microbiology and can be found at: http://iai.asm.org