High Rate of A(H1N1)pdm09 Infections among Rural Thai Villagers, 2009–2010

Background

Pandemic influenza A(H1N1)pdm09 emerged in Thailand in 2009. A prospective longitudinal adult cohort and household transmission study of influenza-like illness (ILI) was ongoing in rural Thailand at the time of emergence. Symptomatic and subclinical A(H1N1)pdm09 infection rates in the cohort and among household members were evaluated.

Methods

A cohort of 800 Thai adults underwent active community-based surveillance for ILI from 2008–2010. Acute respiratory samples from ILI episodes were tested for A(H1N1)pdm09 by qRT-PCR; acute and 60-day convalescent blood samples were tested by A(H1N1)pdm09 hemagglutination inhibition assay (HI). Enrollment, 12-month and 24-month follow-up blood samples were tested for A(H1N1)pdm09 seroconversion by HI. Household members of influenza A-infected cohort subjects with ILI were enrolled in household transmission investigations in which day 0 and 60 blood samples and acute respiratory samples were tested by either qRT-PCR or HI for A(H1N1)pdm09. Seroconversion between annual blood samples without A(H1N1)pdm09-positive ILI was considered as subclinical infection.

Results

The 2-yr cumulative incidence of A(H1N1)pdm09 infection in the cohort in 2009/2010 was 10.8% (84/781) with an annual incidence of 1.2% in 2009 and 9.7% in 2010; 83.3% of infections were subclinical (50% in 2009 and 85.9% in 2010). The 2-yr cumulative incidence was lowest (5%) in adults born ≤1957. The A(H1N1)pdm09 secondary attack rate among household contacts was 47.2% (17/36); 47.1% of these infections were subclinical. The highest A(H1N1)pdm09 secondary attack rate among household contacts (70.6%, 12/17) occurred among children born between 1990 and 2003.

Conclusion

Subclinical A(H1N1)pdm09 infections in Thai adults occurred frequently and accounted for a greater proportion of all A(H1N1)pdm09 infections than previously estimated. The role of subclinical infections in A(H1N1)pdm09 transmission has important implications in formulating strategies to predict and prevent the spread of A(H1N1)pdm09 and other influenza virus strains.     

Activation properties of the redox-modulated chloroplast enzymes glyceraldehyde 3-phosphate dehydrogenase and fructose-1,6-bisphosphatase

Rapid changes of enzyme activity are obtained by post-translational modification of cysteine residues of some chloroplast enzymes. Individual fine-tuning is achieved by specific factors acting upon the redox cycle. In order to study the regulatory properties of these enzymes, they are purified from leaves or in a recombinant form from Escherichia coli . The various factors acting upon the enzyme in vivo can be simulated in vitro. However, in these studies, some subtle technical problems can be encountered. Two cases are presented in this article, and an attempt is made to explain some previous, seemingly contradictory results. The Calvin-cycle enzyme glyceraldehyde 3-phosphate dehydrogenase in its less active A8B8 form can be dissociated and thereby activated in vitro simply by diluting out the protein. On the other hand, activation requires the presence of reduced thioredoxin (Td) and an increase in ionic strength when performed at a high protein concentration, as present in vivo. Chloroplast fructose-1,6-bisphosphatase (FBPase) is purified from E. coli as an enzyme similar to that purified from leaves. However, using the standard protocol for lysis of the bacteria leads to a form with some unusual properties as changed isoelectric point, lack of Ca2+/fructose-1,6-bisphosphate (FBP) dependency of reductive activation, and lack of activity at high pH and high Mg2+ concentration. These observations are used in order to better understand the characteristics of the activation/inactivation process.     

MOLECULAR EVOLUTION OF EUGLENOZOAN PARAXONEMAL ROD GENES par1 AND par2 COINCIDES WITH PHYLOGENETIC RECONSTRUCTION BASED ON SMALL SUBUNIT rDNA DATA1

Emergent flagella of Euglenozoa consist of two prominent structural elements: the axoneme built by microtubules with motor proteins to enable the movement of the flagellum and a highly organized protein structure of unknown function, called the paraxonemal rod (PAR), which consists of two major proteins paralleling the axoneme of euglenid and kinetoplastid emergent flagella. These flagellar structures are considered apomorphic characters of Euglenozoa. We examined the evolution of the genes par1 and par2 encoding the two major proteins, where we could show that these proteins are encoded by two very similar genes found in kinetoplastids and euglenids. The branching pattern indicated a gene duplication before the diversification into euglenids and kinetoplastids. In the clades of the genes, subtrees of euglenid and kinetoplastid monophyla arose. Both genes showed strong genetic diversity with biased GC content at taxon rather than at gene level. We also examined phylogenies inferred from PAR genes that are well in agreement with established small subunit rDNA analyses. Both showed further separation of the euglenid subtree into primary osmotrophs and a phototrophic clade, including secondarily derived osmotrophs.     

Prime-Boost Vaccination with Toxoplasma Lysate Antigen,but Not with a Mixture of Recombinant Protein Antigens,Leads to Reduction of Brain Cyst Formation in BALB/c Mice

IntroductionInfection with the ubiquitous parasite Toxoplasma gondii is a threat for immunocompromised patients and pregnant women and effective immune-prophylaxis is still lacking.MethodsHere we tested a mixture of recombinant T. gondii antigens expressed in different developmental stages, i.e., SAG1, MAG1 and GRA7 (SMG), and a lysate derived from T. gondii tachyzoites (TLA) for prophylactic vaccination against cyst formation. Both vaccine formulations were applied systemically followed by an oral TLA-booster in BALB/c mice.ResultsSystemic priming with SMG and oral TLA-booster did not show significant induction of protective immune responses. In contrast, systemic priming and oral booster with TLA induced higher levels of Toxoplasma-specific IgG, IgG1 and IgG2a in sera as well as high levels of Toxoplasma-specific IgG1 in small intestines. Furthermore, high levels of Toxoplasma-specific Th1-, Th17- and Th2-associated cytokines were only detected in restimulated splenocytes of TLA-vaccinated mice. Importantly, in mice orally infected with T. gondii oocysts, only TLA-vaccination and booster reduced brain cysts. Furthermore, sera from these mice reduced tachyzoites invasion of Vero cells in vitro, indicating that antibodies may play a critical role for protection against Toxoplasma infection. Additionally, supernatants from splenocyte cultures of TLA-vaccinated mice containing high levels of IFN-γ lead to substantial production of nitric oxide (NO) after incubation with macrophages in vitro. Since NO is involved in the control of parasite growth, the high levels of IFN-γ induced by vaccination with TLA may contribute to the protection against T. gondii.ConclusionIn conclusion, our data indicate that prime-boost approach with TLA, but not with the mixture of recombinant antigens SMG, induces effective humoral and cellular Toxoplasma-specific responses and leads to significant reduction of cerebral cysts, thereby presenting a viable strategy for further vaccine development against T. gondii infection.     

A case for more curiosity-driven basic research

Having been selected to be among the exquisitely talented scientists who won the Sandra K. Masur Senior Leadership Award is a tremendous honor. I would like to take this opportunity to make the case for a conviction of mine that I think many will consider outdated. I am convinced that we need more curiosity-driven basic research aimed at understanding the principles governing life. The reasons are simple: 1) we need to learn more about the world around us; and 2) a robust and diverse basic research enterprise will bring ideas and approaches essential for developing new medicines and improving the lives of humankind.When I was a graduate student, curiosity-driven basic research ruled. Studying mating-type switching in budding yeast, for example, was exciting because it was an interesting problem: How can you make two different cells from a single cell in the absence of any external cues? We did not have to justify why it is important to study what many would now consider a baroque question. Scientists and funding agencies alike agreed that this was an exciting biological problem that needed to be solved. I am certain that all scientists of my generation can come up with similar examples.Open in a separate windowAngelika AmonSince the time I was a graduate student, the field of biological research has experienced a revolution. We can now determine the genetic makeup of every species in a week or so and have an unprecedented ability to manipulate any genome. This revolution has led to a sense that we understand the principles governing life and that it is now time to apply this knowledge to cure diseases and make the world a better place. While applying knowledge to improve lives and treat diseases is certainly a worthwhile endeavor, it is important to realize that we are far from having a mechanistic understanding of even the basic principles of biology. What the genomic revolution brought us are lists, some better than others. We now know how many coding genes define a given species and how many protein kinases, GTPases, and so forth there are in the various genomes we sequenced. This knowledge, however, does not even scratch the surface of understanding their function. When I browse the Saccharomyces cerevisiae genome database (my second-favorite website), I am still amazed how many genes there are that have not even been given a name.To me the most important achievement the new genome-sequencing and genome-editing technologies brought us is that nearly every organism can be a model organism now. We can study and manipulate the processes that most fascinate us in the organisms in which they occur, with the exception, of course, of humans. Thus, I believe that the golden era of basic biological research is not behind us but in front of us, and we need more people who will take advantage of the tools that have been developed in the past three decades. I am therefore hoping that many young people will chose a career in basic research and find an exciting question to study. The more of us there are, the more knowledge we will acquire, and the higher the likelihood we will discover something amazing and important. There is so much interesting biology out there that we should strive to understand. Some of my favorite unanswered questions are: What are the biological principles underlying symbiosis and how did it evolve? Why is sleep essential? Why do plants, despite an enormous regenerative potential, never die of cancer? Why do brown bears, despite inactivity, obesity, and high levels of cholesterol, exhibit no signs of atherosclerosis? How do sharks continuously produce teeth?One could, of course, argue that the knowledge we have accumulated over the past 50 years provides a reasonable framework, and it is now time to leave basic science and model organisms behind and focus on what matters—curing diseases, developing methods to produce energy, cleaning up the oceans, preventing global warming, building biological computers, designing organisms, or engineering whatever the current buzz is about. Like David Botstein, who eloquently discussed the importance of basic research in these pages in 2012 (Botstein, 2012 ), I believe that the notion that we already know enough is wrong and the current application-centric view of biology is misguided. Experience has taught us over and over that we cannot predict where the next important breakthrough will be emerge. Many of the discoveries that we consider groundbreaking and that have brought us new medicines or improved our lives in other ways are the result of curiosity-driven basic research. My favorite example is the discovery of penicillin. Alexander Fleming, through the careful study of his (contaminated) bacterial plates, enabled humankind to escape natural selection. More recent success stories such as new cures for hepatitis C, the human papillomavirus vaccine, the HIV-containment regimens, or treatments for BCR-ABL induced chronic myelogenous leukemia have also only been possible because of decades of basic research in model organisms that taught us the principles of life and enabled us to acquire the methodologies critical to develop these treatments. Although work from my own lab on the causes and consequences of chromosome mis-segregation in budding yeast has not led to the development of new treatments, it has taught us a lot about how an imbalanced karyotype, a hallmark of cancer, affects the physiology of cancer cells and creates vulnerabilities in cancer cells that could represent new therapeutic targets.These are but a few examples for why it is important that we scientists must dedicate ourselves to the pursuit of basic knowledge and why we as a society must make funding basic research a priority. Achieving the latter requires that we scientists tell the public about the importance of what we are doing and explain the potential implications of basic research for human health. At the same time, it will be important to manage expectations. We must explain that not every research project will lead to the development of new medicines and that we cannot predict where the next big breakthroughs will materialize. We must further make it clear that this means we have to fund a broad range of basic research at a healthy level. Perhaps a website that collects examples of how basic research has led to breakthroughs in medicine could serve as a showcase for such success stories, bringing the importance of what we do to the public.While conducting research to improve the lives of others is certainly a worthy motivation, it is not the main reason why I get up very early every morning to go to the lab. To me, gaining an understanding of a basic principle in the purest Faustian terms is what I find most rewarding and exciting. Designing and conducting experiments, pondering the results, and developing hypotheses as to how something may work is most exciting, the idea that I, or nowadays the people in my lab, may be (hopefully) the first to discover a new aspect of biology is the best feeling. It is these rare eureka moments, when you first realize how a process works or when you discover something that opens up a new research direction, that make up for all the woes and frustrations that come with being an experimental scientist in an expensive discipline.For me, having a career in curiosity-driven basic research has been immensely rewarding. It is my hope that basic research remains one of the pillars of the American scientific enterprise, attracting the brightest young minds for generations to come. We as a community can help to make this a reality by telling people what we do and highlighting the importance of our work to their lives.     

Increased Maternal and Cord Blood Betatrophin in Gestational Diabetes

Aim

The aim of the study was to compare maternal and cord blood levels of betatrophin – a new peptide potentially controlling beta cell growth - as well as in its mRNA expression in subcutaneous adipose tissue, visceral adipose tissue and placental tissue obtained from pregnant women with normal glucose tolerance (NGT) and gestational diabetes (GDM).

Methods

Serum betatrophin and irisin concentrations were measured by ELISA in 93 patients with GDM and 97 women with NGT between 24 and 28 week of gestation. Additionally, maternal and cord blood betatrophin and irisin, as well as their genes (C19orf80 and Fndc5) expression were evaluated in 20 patients with GDM and 20 women with NGT at term.

Results

In both groups, serum betatrophin concentrations were significantly higher in the patients with GDM than in the controls (1.91 [1.40-2.60] ng/ml vs 1.63 [1.21-2.22] ng/ml, p=0.03 and 3.45 [2.77-6.53] ng/ml vs 2.78 [2.16-3.65] ng/ml, p=0.03, respectively). Cord blood betatrophin levels were also higher in the GDM than in the NGT group (20.43 [12.97-28.80] ng/ml vs 15.06 [10.11-21.36] ng/ml, p=0.03). In both groups betatrophin concentrations in arterial cord blood were significantly higher than in maternal serum (p=0.0001). Serum irisin levels were significantly lower in the patients with GDM (1679 [1308-2171] ng/ml) than in the healthy women between 24 and 28 week of pregnancy (1880 [1519-2312] ng/ml, p=0.03). Both C19orf80 and Fndc5 mRNA expression in fat and placental tissue did not differ significantly between the groups studied.

Conclusions

Our results suggest that an increase in maternal and cord blood betatrophin might be a compensatory mechanism for enhanced insulin demand in GDM.     

Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation

Background

Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity.

Methods

Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis.

Results

Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6–12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72).

Conclusions

Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations.