The Autoimmune Regulator (AIRE), Which Is Defective in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy Patients, Is Expressed in Human Epidermal and Follicular Keratinocytes and Associates With the Intermediate Filament Protein Cytokeratin 17

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome, which is caused by mutation of the autoimmune regulator (AIRE) gene, is a highly variable disease characterized by multiple endocrine failure, chronic mucocutaneous candidiasis, and various ectodermal defects. AIRE is a transcriptional regulator classically expressed in medullary thymic epithelial cells, monocytes, macrophages, and dendritic cells. Previous studies have suggested that AIRE can shuttle between the nucleus and cytoplasm of cells, although its cytoplasmic functions are poorly characterized. Through mass spectrometry analysis of proteins co-immunoprecipitating with cytoplasmic AIRE, we identified a novel association of AIRE with the intermediate filament protein cytokeratin 17 (K17) in the THP-1 monocyte cell line. We confirmed AIRE expression in HaCaT epidermal keratinocytes, as well as its interaction with K17. Confocal microscopy of human fetal and adult scalp hair follicles demonstrated a cytoplasmic pattern of AIRE staining that moderately colocalized with K17. The cytoplasmic association of AIRE with the intermediate filament network in human epidermal and follicular keratinocytes may provide a new path to understanding the ectodermal abnormalities associated with the APECED syndrome. (Am J Pathol 2011, 178:983-988; DOI: 10.1016/j.ajpath.2010.12.007)

Functional Characterization of LcpA, a Surface-Exposed Protein of Leptospira spp. That Binds the Human Complement Regulator C4BP

We have previously shown that pathogenic leptospiral strains are able to bind C4b binding protein (C4BP). Surface-bound C4BP retains its cofactor activity, indicating that acquisition of this complement regulator may contribute to leptospiral serum resistance. In the present study, the abilities of seven recombinant putative leptospiral outer membrane proteins to interact with C4BP were evaluated. The protein encoded by LIC11947 interacted with this human complement regulator in a dose-dependent manner. The cofactor activity of C4BP bound to immobilized recombinant LIC11947 (rLIC11947) was confirmed by detecting factor I-mediated cleavage of C4b. rLIC11947 was therefore named LcpA (for leptospiral complement regulator-acquiring protein A). LcpA was shown to be an outer membrane protein by using immunoelectron microscopy, cell surface proteolysis, and Triton X-114 fractionation. The gene coding for LcpA is conserved among pathogenic leptospiral strains. This is the first characterization of a Leptospira surface protein that binds to the human complement regulator C4BP in a manner that allows this important regulator to control complement system activation mediated either by the classical pathway or by the lectin pathway. This newly identified protein may play a role in immune evasion by Leptospira spp. and may therefore represent a target for the development of a human vaccine against leptospirosis.

TLR2 Is a Negative Regulator of Th17 Cells and Tissue Pathology in a Pulmonary Model of Fungal Infection

To study the role of TLR2 in a experimental model of chronic pulmonary infection, TLR2-deficient and wild-type mice were intratracheally infected with Paracoccidioides brasiliensis, a primary fungal pathogen. Compared with control, TLR2(-/-) mice developed a less severe pulmonary infection and decreased NO synthesis. Equivalent results were detected with in vitro-infected macrophages. Unexpectedly, despite the differences in fungal loads both mouse strains showed equivalent survival times and severe pulmonary inflammatory reactions. Studies on lung-infiltrating leukocytes of TLR2(-/-) mice demonstrated an increased presence of polymorphonuclear neutrophils that control fungal loads but were associated with diminished numbers of activated CD4(+) and CD8(+) T lymphocytes. TLR2 deficiency leads to minor differences in the levels of pulmonary type 1 and type 2 cytokines, but results in increased production of KC, a CXC chemokine involved in neutrophils chemotaxis, as well as TGF-beta, IL-6, IL-23, and IL-17 skewing T cell immunity to a Th17 pattern. In addition, the preferential Th17 immunity of TLR2(-/-) mice was associated with impaired expansion of regulatory CD4(+)CD25(+)FoxP3(+) T cells. This is the first study to show that TLR2 activation controls innate and adaptive immunity to P. brasiliensis infection. TLR2 deficiency results in increased Th17 immunity associated with diminished expansion of regulatory T cells and increased lung pathology due to unrestrained inflammatory reactions. The Journal of Immunology, 2009, 183: 1279-1290.

Immune Evasion of Leptospira Species by Acquisition of Human Complement Regulator C4BP

Leptospirosis is a spirochetal zoonotic disease of global distribution with a high incidence in tropical regions. In the last 15 years it has been recognized as an important emerging infectious disease due to the occurrence of large outbreaks in warm-climate countries and, occasionally, in temperate regions. Pathogenic leptospires efficiently colonize target organs after penetrating the host. Their invasiveness is attributed to the ability to multiply in blood, adhere to host cells, and penetrate into tissues. Therefore, they must be able to evade the innate host defense. The main purpose of the present study was to evaluate how several Leptospira strains evade the protective function of the complement system. The serum resistance of six Leptospira strains was analyzed. We demonstrate that the pathogenic strain isolated from infected hamsters avoids serum bactericidal activity more efficiently than the culture-attenuated or the nonpathogenic Leptospira strains. Moreover, both the alternative and the classical pathways of complement seem to be responsible for the killing of leptospires. Serum-resistant and serum-intermediate strains are able to bind C4BP, whereas the serum-sensitive strain Patoc I is not. Surface-bound C4BP promotes factor I-mediated cleavage of C4b. Accordingly, we found that pathogenic strains displayed reduced deposition of the late complement components C5 to C9 upon exposure to serum. We conclude that binding of C4BP contributes to leptospiral serum resistance against host complement.

CztR, a LysR-Type Transcriptional Regulator Involved in Zinc Homeostasis and Oxidative Stress Defense in Caulobacter crescentus

Caulobacter crescentus is a free-living alphaproteobacterium that has 11 predicted LysR-type transcriptional regulators (LTTRs). Previously, a C. crescentus mutant strain with a mini-Tn5lacZ transposon inserted into a gene encoding an LTTR was isolated; this mutant was sensitive to cadmium. In this work, a mutant strain with a deletion was obtained, and the role of this LTTR (called CztR here) was evaluated. The transcriptional start site of this gene was determined by primer extension analysis, and its promoter was cloned in front of a lacZ reporter gene. beta-Galactosidase activity assays, performed with the wild-type and mutant strains, indicated that this gene is 2-fold induced when cells enter stationary phase and that it is negatively autoregulated. Moreover, this regulator is essential for the expression of the divergent cztA gene at stationary phase, in minimal medium, and in response to zinc depletion. This gene encodes a hypothetical protein containing 10 predicted transmembrane segments, and its expression pattern suggests that it encodes a putative zinc transporter. The cztR strain was also shown to be sensitive to superoxide (generated by paraquat) and to hydrogen peroxide but not to tert-butyl hydroperoxide. The expression of katG and ahpC, but not that of the superoxide dismutase genes, was increased in the cztR mutant. A model is proposed to explain how CztR binding to the divergent regulatory regions could activate cztA expression and repress its own transcription.

SpdR, a Response Regulator Required for Stationary-Phase Induction of Caulobacter crescentus cspD

The cold shock protein (CSP) family includes small polypeptides that are induced upon temperature downshift and stationary phase. The genome of the alphaproteobacterium Caulobacter crescentus encodes four CSPs, with two being induced by cold shock and two at the onset of stationary phase. In order to identify the environmental signals and cell factors that are involved in cspD expression at stationary phase, we have analyzed cspD transcription during growth under several nutrient conditions. The results showed that expression of cspD was affected by the medium composition and was inversely proportional to the growth rate. The maximum levels of expression were decreased in a spoT mutant, indicating that ppGpp may be involved in the signalization for carbon starvation induction of cspD. A Tn5 mutant library was screened for mutants with reduced cspD expression, and 10 clones that showed at least a 50% reduction in expression were identified. Among these, a strain with a transposon insertion into a response regulator of a two-component system showed no induction of cspD at stationary phase. This protein (SpdR) was able to acquire a phosphate group from its cognate histidine kinase, and gel mobility shift assay and DNase I footprinting experiments showed that it binds to an inverted repeat sequence of the cspD regulatory region. A mutated SpdR with a substitution of the conserved aspartyl residue that is the probable phosphorylation site is unable to bind to the cspD regulatory region and to complement the spdR mutant phenotype.

Pseudomonas aeruginosa PA14 cupD transcription is activated by the RcsB response regulator, but repressed by its putative cognate sensor RcsC

The opportunistic pathogen Pseudomonas aeruginosa PA14 possesses four fimbrial cup clusters, which may confer the ability to adapt to different environments. cupD lies in the pathogenicity island PAPI-1 next to genes coding for a putative phosphorelay system composed of the hybrid histidine kinase RcsC and the response regulator RcsB. The main focus of this work was the regulation of cupD at the mRNA level. It was found that the HN-S-like protein MvaT does not exert a strong influence on cupD transcript levels, as it does for cupA. cupD transcription is higher in cultures grown at 28 degrees C, which agrees with a cupD mutant presenting attenuated virulence only in a plant model, but not in a mouse model of infection. Whereas an rcsC in-frame deletion mutant presented higher levels of cupD mRNA, rcsB deletion had the opposite effect. Accordingly, overexpression of RcsB increased the levels of cupD transcription, and promoted biofilm formation and the appearance of fimbriae. A single transcription start site was determined for cupD and transcription from this site was induced by RcsB. A motif similar to the enterobacterial RcsB/RcsA-binding site was detected adjacent to the -35 region, suggesting that this could be the RcsB-binding site. Comparison of P. aeruginosa and Escherichia coli Rcs may provide insights into how similar systems can be used by different bacteria to control gene expression and to adapt to various environmental conditions.

Closed-circuit Television Students Film a Voltage-regulator check by William C.H. Meyers

One of a series of photographs accompanying a press release by the New York Trade School announcing the development and demonstration of a new technique in closed-circuit TV. Student Dennis Mahoney serves as one of the cameramen as William C. H. Meyers of the Automotive Department performs the demonstration. Black and white photograph.

Growth regulator losses from cotton plants due to rainfall

Reguladores de crescimento aplicados às plantas de algodoeiro (Gossypium hirsutum L.) podem ser lavados em função da ocorrência de chuvas. Chuvas que ocorrem próximas à época de aplicação podem ocasionar elevada perda e necessidade de reaplicação dos produtos visando à taxa de crescimento desejada. Avaliou-se o efeito do intervalo de tempo entre a ocorrência de chuva simulada e a aplicação de cloreto de mepiquat e cloreto de chlormequat no algodoeiro no crescimento das plantas, além de estimar a necessidade de reaplicação dos reguladores. Plantas de algodão foram cultivadas em vasos de 12 L que permaneceram em casa de vegetação. Os reguladores de crescimento foram aplicados 40 dias após a emergência, quando 50% das plantas apresentavam botão floral. A chuva foi simulada 1, 2, 4, 6 e 24 horas após a aplicação dos reguladores. Determinou-se a altura das plantas antes da aplicação dos produtos e a cada 3 dias até o 30º dia. Na colheita, foi avaliado o número de ramos e estruturas reprodutivas, com posterior determinação da massa da matéria seca. Também foi determinado o crescimento acumulado e taxa de crescimento das plantas. Os dois reguladores reduziram a massa da matéria seca das plantas, independente do intervalo para ocorrência da chuva. O crescimento excessivo das plantas foi controlado, porém, com eficiência reduzida quanto menor o intervalo para simulação de chuva. em todos os períodos avaliados houve perda de produtos, com necessidade de reaplicação. A taxa de reaplicação de cloreto de mepiquat para os diferentes intervalos de chuva foi, em média, 17% maior.

Plant growth regulator losses in cotton as affected by adjuvants and rain

Nas maiores regiões algodoeiras no Brasil, chove mais de 1.500mm anuais, existindo risco de ocorrer lavagem de reguladores de crescimento aplicados às folhas do algodoeiro, antes que sejam absorvidos. O objetivo deste trabalho foi avaliar a lavagem dos reguladores de crescimento cloreto de mepiquat e cloreto de chlormequat de folhas de algodoeiro por chuva, ocorrendo em diferentes momentos após a aplicação. O trabalho foi realizado em casa de vegetação. Ambos os reguladores foram aplicados no aparecimento do primeiro botão floral, na dose de 15g ha-1 de i.a. com e sem adjuvante siliconado, e chuva simulada foi aplicada aos 0, 0,75; 1,5; 3,0; 6,0; 12,0 e 24 horas após a aplicação dos reguladores, mais um tratamento sem chuva. A adição de adjuvante siliconado melhorou a absorção dos produtos. A ocorrência de chuva até mesmo 24 horas após a aplicação dos reguladores pode lavar parte dos produtos das plantas de algodoeiro, com maior intensidade para o tratamento sem adjuvante. A redução da absorção do produto leva à necessidade de reaplicá-lo para que possa haver a sua ação, sem comprometer sua função.

Single-phase high power-factor boost ZCS pre-regulator operating in critical conduction mode

This paper presents a new single-phase interleaved high power factor boost pre-regulator operating in critical conduction mode, where the switches and boost diode performing zero-current commutations during its turn-off, eliminating the disadvantages related to the reverse recovery losses and electromagnetic interference problems of the boost diode, when operating in the continuous conduction mode. The interleaving technique is applied in the power cell, providing a significant input current ripple reduction in comparison to discontinuous mode of operation, due to its input current continuous conduction operation. This paper presents a complete modeling for the converter operating in critical conduction mode, resulting in an improved design procedure for interleaved techniques with high input power factor, a complete design procedure, and main simulation results from a design example with two interleaved cells rated at 1kW, 400V output voltage and 220V rms input voltage.

Design of a Takagi-Sugeno Fuzzy Regulator for a Set of Operation Points

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Potential of the insect growth regulator, fluazuron, in the control of Rhipicephalus sanguineus nymphs (Latreille, 1806) (Acari: Ixodidae): Determination of the LD95 and LD50

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A phase-shifting control for variable frequency multi-cells interleaved boost pre-regulator based on FPGA device

In this paper were investigated phase-shift control strategies applied to a four cells interleaved high input-power-factor pre-regulator boost rectifier, operating in critical conduction mode, using a non-dissipative commutation cells and frequency modulation. The digital control has been developed using a hardware description language (VHDL) and implemented using the XC2S200E-SpartanII-E/Xilinx FPGA, performing a true critical conduction operation mode for a generic number of interleaved cells. Experimental results are presented, in order to verify the feasibility and performance of the proposed digital control, through the use of a Xilinx FPGA device.

Effect of the insect growth regulator diflubenzuron on the predator Podisus nigrispinus (Heteroptera: Pentatomidae)

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a common natural predator of defoliating caterpillars in agricultural and forest systems. Insecticides acting as growth regulators of insect pests can indirectly affect their predators through consumption of contaminated prey. We examined the reproductive performance of P. nigrispinus fed on caterpillars of Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae) reared on soybean leaves exposed to the chitin synthesis inhibitor, diflubenzuron. Caterpillars of A. gemmatalis were fed for 12 h with treated soybean leaves and offered to adults of the predator P. nigrispinus over five consecutive days. The fertility of P. nigrispinus was reduced when feeding on diflubenzuron treated caterpillars, especially at the beginning of the reproductive period, but recovered 3 weeks later. The effects of diflubenzuron ingestion on the life table parameters of P. nigrispinus included an increase in the period taken to double the population size, and reductions in the intrinsic rate of population increase, generation duration, and net reproductive rate. Diflubenzuron therefore had an indirect negative effect on the reproduction and the population dynamics of the non-target predator P. nigrispinus. Clearly, its use in integrated pest management requires further evaluation.