Membrane applications for microalgae cultivation and harvesting: a review

With renewed interest in microalgae due to their potential for biofuel and bioproducts production, efficient cultivation and harvesting mechanisms are needed to increase the economic competitiveness of microalgal products against traditional sources. With pore sizes ranging from microns to angstroms, membranes provide tailored functions for solid/liquid separation (cell retention, biomass concentration and dewatering), gas/liquid separation (gas delivery and removal), and solute/liquid separation (bioproduct recovery, feedstock preparation and effluent recycling) that are problematic or not possible with other technologies. Existing knowledge on membrane systems used in other disciplines, such as environmental engineering, marine science, and biomedicine, can be applied to algae production. Though membranes have great potential to facilitate cultivation and harvesting, challenges in energy reduction and fouling mitigation need to be overcome for long-term, cost-effective application.     

Rapid Molecular Assays for the Detection of Yellow Fever Virus in Low-Resource Settings

Background

Yellow fever (YF) is an acute viral hemorrhagic disease transmitted by Aedes mosquitoes. The causative agent, the yellow fever virus (YFV), is found in tropical and subtropical areas of South America and Africa. Although a vaccine is available since the 1930s, YF still causes thousands of deaths and several outbreaks have recently occurred in Africa. Therefore, rapid and reliable diagnostic methods easy to perform in low-resources settings could have a major impact on early detection of outbreaks and implementation of appropriate response strategies such as vaccination and/or vector control.

Methodology

The aim of this study was to develop a YFV nucleic acid detection method applicable in outbreak investigations and surveillance studies in low-resource and field settings. The method should be simple, robust, rapid and reliable. Therefore, we adopted an isothermal approach and developed a recombinase polymerase amplification (RPA) assay which can be performed with a small portable instrument and easy-to-use lyophilized reagents. The assay was developed in three different formats (real-time with or without microfluidic semi-automated system and lateral-flow assay) to evaluate their application for different purposes. Analytical specificity and sensitivity were evaluated with a wide panel of viruses and serial dilutions of YFV RNA. Mosquito pools and spiked human plasma samples were also tested for assay validation. Finally, real-time RPA in portable format was tested under field conditions in Senegal.

Conclusion/Significance

The assay was able to detect 20 different YFV strains and demonstrated no cross-reactions with closely related viruses. The RPA assay proved to be a robust, portable method with a low detection limit (<21 genome equivalent copies per reaction) and rapid processing time (<20 min). Results from real-time RPA field testing were comparable to results obtained in the laboratory, thus confirming our method is suitable for YFV detection in low-resource settings.     

The promoter of filamentation (POF1) protein from <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> is an ATPase involved in the protein quality control process

Background

The gene YCL047C, which has been renamed promoter of filamentation gene (POF1), has recently been described as a cell component involved in yeast filamentous growth. The objective of this work is to understand the molecular and biological function of this gene.

Results

Here, we report that the protein encoded by the POF1 gene, Pof1p, is an ATPase that may be part of the Saccharomyces cerevisiae protein quality control pathway. According to the results, Δpof1 cells showed increased sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, heat shock and protein unfolding agents, such as dithiothreitol and tunicamycin. Besides, the overexpression of POF1 suppressed the sensitivity of Δpct1, a strain that lacks a gene that encodes a phosphocholine cytidylyltransferase, to heat shock. In vitro analysis showed, however, that the purified Pof1p enzyme had no cytidylyltransferase activity but does have ATPase activity, with catalytic efficiency comparable to other ATPases involved in endoplasmic reticulum-associated degradation of proteins (ERAD). Supporting these findings, co-immunoprecipitation experiments showed a physical interaction between Pof1p and Ubc7p (an ubiquitin conjugating enzyme) in vivo.

Conclusions

Taken together, the results strongly suggest that the biological function of Pof1p is related to the regulation of protein degradation.

     

Community-Based Control of the Brown Dog Tick in a Region with High Rates of Rocky Mountain Spotted Fever, 2012–2013

Rocky Mountain spotted fever (RMSF) transmitted by the brown dog tick (Rhipicephalus sanguineus sensu lato) has emerged as a significant public health risk on American Indian reservations in eastern Arizona. During 2003–2012, more than 250 RMSF cases and 19 deaths were documented among Arizona''s American Indian population. The high case fatality rate makes community-level interventions aimed at rapid and sustained reduction of ticks urgent. Beginning in 2012, a two year pilot integrated tick prevention campaign called the RMSF Rodeo was launched in a ∼600-home tribal community with high rates of RMSF. During year one, long-acting tick collars were placed on all dogs in the community, environmental acaricides were applied to yards monthly, and animal care practices such as spay and neuter and proper tethering procedures were encouraged. Tick levels, indicated by visible inspection of dogs, tick traps and homeowner reports were used to monitor tick presence and evaluate the efficacy of interventions throughout the project. By the end of year one, <1% of dogs in the RMSF Rodeo community had visible tick infestations five months after the project was started, compared to 64% of dogs in Non-Rodeo communities, and environmental tick levels were reduced below detectable levels. The second year of the project focused on use of the long-acting collar alone and achieved sustained tick control with fewer than 3% of dogs in the RMSF Rodeo community with visible tick infestations by the end of the second year. Homeowner reports of tick activity in the domestic and peridomestic setting showed similar decreases in tick activity compared to the non-project communities. Expansion of this successful project to other areas with Rhipicephalus-transmitted RMSF has the potential to reduce brown dog tick infestations and save human lives.     

Relationships among msx gene structure and function in zebrafish and other vertebrates

The zebrafish genome contains at least five msx homeobox genes, msxA, msxB, msxC, msxD, and the newly isolated msxE. Although these genes share structural features common to all Msx genes, phylogenetic analyses of protein sequences indicate that the msx genes from zebrafish are not orthologous to the Msx1 and Msx2 genes of mammals, birds, and amphibians. The zebrafish msxB and msxC are more closely related to each other and to the mouse Msx3. Similarly, although the combinatorial expression of the zebrafish msx genes in the embryonic dorsal neuroectoderm, visceral arches, fins, and sensory organs suggests functional similarities with the Msx genes of other vertebrates, differences in the expression patterns preclude precise assignment of orthological relationships. Distinct duplication events may have given rise to the msx genes of modern fish and other vertebrate lineages whereas many aspects of msx gene functions during embryonic development have been preserved.      

Case–control association study of polymorphisms in the angiotensinogen and angiotensin-converting enzyme genes and coronary artery disease and systemic artery hypertension in African-Brazilians and Caucasian-Brazilians

The rennin–angiotensin–aldosterone system (RAAS) is a critical pathway in regulating blood pressure and salt/water homeostasis, possessing an intimate relationship with the development of systemic artery hypertension (SAH). Once hypertension is considered a risk factor for coronary artery disease (CAD), the RAAS is also related to this pathology. This investigation aimed to analyse if the frequencies of AGT M235T (rs699) and ACE I/D (rs4646994) polymorphisms are associated with CAD and SAH in African-Brazilians and Caucasian-Brazilians. In this study we analysed 714 subjects who underwent coronary angiography to detect obstructive lesions and CAD, as well as blood pressure measurement and SAH, grouped according to ethnicity: 266 African-Brazilians and 448 Caucasian-Brazilians. Among CAD and SAH cases and controls, the genotype and allele frequencies of ACE I/D polymorphism were similar in both ethnic groups. The AGT 235TT genotype and 235T allele frequencies were higher in SAH cases (32%, 54.7%) versus controls in Caucasian-Brazilians (19.8%, 46.4%; P= 0.038, P= 0.031, respectively). The AGT 235TT (OR = 1.8; P= 0.028) demonstrated to be an independent factor risk in a multivariate logistic regression increasing SAH risk in Caucasians but not in African-Brazilians. In summary, AGT M235T polymorphism was associated with SAH risk in Caucasian-Brazilians, and no association was detected with CAD. No association was also observed in ACE I/D polymorphism either in CAD or SAH in African-Brazilians and Caucasian-Brazilians.     

Reactivity patterns of monoclonal antibodies positive on myelomonocytic leukemia cells as defined by esterase isoenzyme analysis

Summary The reactivity with monoclonal antibodies (MoAbs) specific for myelomonocytic cells and the expression of a particular esterase isoenzyme were analyzed in 159 cases of acute myeloid leukemias. The incidence of positivity of 16 MoAbs (MCS-2, MCS-1, OKM1, My-1, Leu-M1, Leu-M3, CA-2-38, MY4, MY7, MY8, MY9, VIM-D2, VIM-D5, Mo1, Mo2, 63D3) was studied using the indirect immunofluorescence technique. A carboxylic esterase isoenzyme which can be inhibited completely and selectively by sodium fluoride (NaF) was demonstrated by isoelectric focusing on horizontal polyacrylamide gels. This NaF-sensitive isoenzyme indicated the monocytic origin of the blast cells as it is specific for this cell lineage. Prior to the immunological-isoenzymatic analysis all cases were categorized into two subtypes according to morphological criteria of the FAB classification system: 147 cases of AML (FAB M1-3) and 12 cases of AMMoL/AMoL (FAB M4/5). However, 15 out of 147 cases of AML expressed the NaF-sensitive isoenzyme and were therefore assigned to the group AMMoL/AMoL. Likewise, 1 case, diagnosed morphologically as AMMoL, was negative for this marker isoenzyme and was assigned to the other leukemia subtype. The incidence of reactivity varied widely for the MoAbs tested regarding the overall results on all cases and the positivity on cases of either AML or AMMoL/AMoL. The MoAbs were grouped into four classes depending on the pattern of reactivity with myeloblastic or monoblastic or both subtypes of acute myeloid leukemia. The MoAbs MCS-2, MY7, Leu-M1, and MY9 detected the vast majority of cases with either myelocytic or monocytic involvement (group-I: pan-myelomonocytic reactivity). The MoAbs MCS-1, OKM1, VIM-D5, and Mo1 showed a predominance in their staining pattern for monocytic variants, but were also positive on a substantial percentage of nonmonocytic cases (group-II: predominantly reactive with monocytic, but also myelocytic cases). The MoAbs Leu-M3, MY4, VIM-D2, Mo2, and MY8 reacted with the large majority of AMMoL/AMoL cases and with a small number of AML cases (group-III: monocyte-specific reactivity). The MoAbs of group-I are useful in differentiating acute lymphoid from acute myeloid leukemias. The MoAbs of group-III, and to a lower extent those of group-II, will be of considerable value in the subtyping of acute myeloid leukemias. The results show that (1) accuracy of leukemia classification might not always be achieved by morphology alone, but that immunological and biochemical aspects should be included as well, and (2) several MoAbs are very useful tools for classification and subtyping of acute myeloid leukemias.     

Phenotyping of malignant hematopoietic cells. Analysis of 1200 cases of leukemia-lymphoma

1255 cases of leukemia-lymphoma were tested between 1972 and 1984 by multiple marker analysis. Routine leukemia phenotyping was performed using standard morphological and cytochemical techniques in combination with clinical and histo-pathological information; the main emphasis was put on immunological surface marker analysis using erythrocyte rosette assays, TdT and a large panel of poly- and monoclonal antibody tests. The 1255 cases were divided into these major types and subtypes: 349 cases of ALL and related immature T- and Burkitt-lymphomas (cALL, pre B-ALL, B-ALL and Burkitt-lymphomas, T-ALL and immature, mostly leukemic T-lymphomas, Null-ALL), 454 cases of mature T- and B-cell malignancies (T-CLL, mycosis fungoides, Sezary-syndrome, T-lymphomas, B-CLL, hairy cell leukemia, multiple myeloma, B-lymphomas), 263 cases of acute myeloid leukemias (AML, AMMoL/AMoL), 182 cases of chronic myeloid leukemias (CML in chronic phase, CMoL, CML in blast crisis), 6 cases of erythroleukemia and 1 case of megakaryoblastic leukemia. A simplified classification scheme which has been used in our laboratories is presented. Phenotyping is of diagnostic, prognostic and therapeutic relevance, most evidently for patients with ALL. Routine leukemia phenotyping should be performed with highly standardized techniques and reagents and by combining information from several fields in the multiple marker analysis. New areas of leukemia research might become very useful for the routine procedure of phenotyping.