In plants and animals, innate immunity is triggered through pattern recognition receptors (PRRs) in response to microbe-associated molecular patterns (MAMPs) to provide the first line of inducible defense. Plant receptor protein kinases (RPKs) represent the main plasma membrane PRRs perceiving diverse MAMPs. RPKs also recognize secondary danger-inducible plant peptides and cell-wall signals. Both types of RPKs trigger rapid and convergent downstream signaling networks controlled by calcium-activated PKs and mitogen-activated PK (MAPK) cascades. These PK signaling networks serve specific and overlapping roles in controlling the activities and synthesis of a plethora of transcription factors (TFs), enzymes, hormones, peptides and antimicrobial chemicals, contributing to resistance against bacteria, oomycetes and fungi.

Background/Aims: Polycystic ovary syndrome (PCOS) has been found to affect 4-8% of women of reproductive age; however, in Mexican-Americans a prevalence of 12.8% has been reported. This study determines the prevalence of PCOS in a sample of Mexican women. Methods: This prospective cross-sectional study included 150 female Mexican volunteers aged 20-45 years. Menstrual cycles were recorded and hirsutism was graded. Pelvic ultrasound was performed and androgen levels were measured. PCOS was diagnosed by hyperandrogenism and/or hyperandrogenemia, and oligo-ovulation (NIH 1990 criteria), and also by 2 of 3 findings: oligo-ovulation, clinical and/or biochemical hyperandrogenism and polycystic ovaries (PCO)(Rotterdam 2003 criteria), excluding other disorders. Results: Nine of the 150 women were diagnosed with PCOS, a prevalence of 6.0%(95% CI: 1.9-10.1%), according to NIH criteria. The ultrasound morphology added one patient to give ten PCOS patients, a prevalence of 6.6%(95% CI: 2.3-10.9%) according to Rotterdam criteria. All PCOS patients presented oligo-ovulation, 9 had hirsutism and 7 of them had acne. Eight of the 10 PCOS patients had morphologic characteristics of PCO. Conclusion: The prevalence of PCOS in Mexican women is approximately 6.0%, similar to other populations, but lower than 12.8% reported in Mexican-American women.

A principal question in MAP kinase (MAPK/MPK) cascade signalling is how similar components dictate different specificity in the information-processing machineries from yeast to humans and plants. In Arabidopsis, how MPK3/6 modulates distinct outputs in diverse signal transduction pathways remains elusive. By combining systematic cellular and genetic screens, here we uncover a previously unexpected MKK9-MPK3/MPK6 cascade promoting ethylene-insensitive 3 (EIN3)-mediated transcription in ethylene signalling. The mkk9 mutant exhibits a broad spectrum of moderate ethylene-insensitive phenotypes, and translocated MKK9 governs nuclear signalling downstream of receptors. Breaking a linear model and conventional MAPK signalling, ethylene inactivates the negative regulator constitutive triple response 1 (CTR1, a Raf-like MAPK kinase kinase (MAPKKK)) to activate the positive MKK9-MPK3/6 cascade. The bifurcate and antagonistic CTR1 and MKK9 pathways are both critical in determining ethylene-signalling specificity through two MAPK phosphorylation sites with opposite effects on EIN3 stability. The results suggest a new paradigm for linking intertwined MAPK cascades to control quantitative responses and specificity in signalling networks.

OBJECTIVE: To assess message expression of adiponectin and leptin in visceral and SC fat in women with polycystic ovary syndrome (PCOS) and in control women. DESIGN: Prospective clinical trial. SETTING: Academic medical centers in Mexico City, Mexico and New York, New York. PATIENT(S): Women with PCOS and control women. INTERVENTION(S): Surgical biopsies of visceral (omental) and subcutaneous (SC) adipose tissue, fasting blood samples, and ultrasound measurements of visceral and SC fat. MAIN OUTCOME MEASURE(S): Messenger RNA assessment of adiponectin and leptin in adipose tissue samples; serum measurements of adiponectin, leptin, glucose, insulin, and hormone levels; measurements of fat quantity by ultrasound. Correlative analyses as well as comparisons between women with PCOS and control women were performed. RESULT(S): Confirming previous data, women with PCOS had more insulin resistance, similar serum leptin, but lower serum adiponectin compared with control women. When control women were divided into quartiles by body mass index (BMI), messenger RNA expression of leptin and adiponectin decreased with increasing BMI. Adiponectin and leptin expression was significantly lower in women with PCOS; in weight-matched patients and control women, leptin and adiponectin expression was statistically significantly lower in SC tissue, and adiponectin expression was statistically significantly lower in omental tissue in women with PCOS. In control women, there was greater expression in SC tissue compared with in visceral tissue. There were significant negative correlations between visceral and SC fat mass by both ultrasound as well as adiponectin and leptin expression in women with PCOS. Serum adiponectin correlated statistically significantly with visceral adiponectin expression (r = 0.64) in women with PCOS, and there was a statistically significant correlation between SC adiponectin expression and the Quantitative Insulin-Sensitivity Check Index as a marker of insulin resistance (r = 0.43). CONCLUSION(S): Adipocytokine expression in fat tissue appears to be down-regulated by an increased fat mass; this is particularly evident in the case of adiponectin expression in women with PCOS. It is probable that insulin resistance is a factor that may contribute, in part, to these findings.

Major research efforts are directed towards the development of a better antimycobacterial vaccine. But progress in the field of tuberculosis vaccine development has been hampered by the lack of human in vitro models to assess vaccine immunogenicity and efficacy. New candidate vaccines will have to be evaluated against the existing Mycobacterium bovis BCG "gold standard." It is therefore important to understand the type of immune responses elicited by BCG vaccination to enable comparisons with potential new candidates. We used a novel human in vitro whole-blood model, which measures immune responses to mycobacteria by use of reporter gene-tagged BCG (BCG lux), to study immune responses to BCG vaccination in 50 neonates in a setting in Cape Town, Republic of South Africa, where tuberculosis is endemic. BCG vaccination significantly reduced growth of BCG lux in whole blood (prevaccination median growth ratio [GR], 9.6; range, 1.3 to 24; postvaccination median GR, 3.9; range, 0.6 to 12.2 [P < 0.0001]). Growth of BCG lux was better restricted in vaccinated infants than in unvaccinated age-matched controls (n = 4). BCG vaccination induced significantly higher gamma interferon production in response to BCG lux (P < 0.0001) and to purified protein derivative (P = 0.0001). No significant changes in either growth of BCG lux or cytokine production occurred in an adult control group (n = 6) over the study period. The whole-blood luminescence model detects changes in cellular immune responses to mycobacteria induced by BCG vaccination. It is therefore a useful new tool in studying the immunogenicity of newly developed vaccine candidates prior to large field trials assessing efficacy.

The mechanisms of protective immunity to tuberculosis remain poorly understood in humans. A whole-blood infection model that employs a luminescent readout was used to analyze the role of T cells in control of mycobacterial infection. Control of mycobacterial growth in blood from healthy tuberculin-positive individuals was shown to be mediated predominantly by CD4(+) T cells. Comparison of age-matched cohorts of human immunodeficiency virus (HIV)-infected and -uninfected children from South Africa demonstrated an association between low CD4 cell counts, low interferon (IFN)-gamma production, and impaired ability to regulate growth of Mycobacterium bovis bacille Calmette-Guérin in blood from HIV-infected children. Impaired control of infection was not reconstituted by the addition of exogenous IFN-gamma. The whole-blood assay provides an important tool for monitoring and dissecting of human immune responses to mycobacterial infection.

There is remarkable conservation in the recognition of pathogen-associated molecular patterns (PAMPs) by innate immune responses of plants, insects and mammals. We developed an Arabidopsis thaliana leaf cell system based on the induction of early-defence gene transcription by flagellin, a highly conserved component of bacterial flagella that functions as a PAMP in plants and mammals. Here we identify a complete plant MAP kinase cascade (MEKK1, MKK4/MKK5 and MPK3/MPK6) and WRKY22/WRKY29 transcription factors that function downstream of the flagellin receptor FLS2, a leucine-rich-repeat (LRR) receptor kinase. Activation of this MAPK cascade confers resistance to both bacterial and fungal pathogens, suggesting that signalling events initiated by diverse pathogens converge into a conserved MAPK cascade.

Mitogen-activated protein kinase (MAPK) cascades have emerged as a universal signal transduction mechanism that connects diverse receptors/sensors to cellular and nuclear responses in eukaryotes. Recent studies in plants indicate that MAPK cascades are vital to fundamental physiological functions involved in hormonal responses, cell cycle regulation, abiotic stress signaling, and defense mechanisms. New findings have revealed the complexity and redundancy of the signaling components, the antagonistic nature of distinct pathways, and the use of both positive and negative regulatory mechanisms.

Despite the recognition of H(2)O(2) as a central signaling molecule in stress and wounding responses, pathogen defense, and regulation of cell cycle and cell death, little is known about how the H(2)O(2) signal is perceived and transduced in plant cells. We report here that H(2)O(2) is a potent activator of mitogen-activated protein kinases (MAPKs) in Arabidopsis leaf cells. Using epitope tagging and a protoplast transient expression assay, we show that H(2)O(2) can activate a specific Arabidopsis mitogen-activated protein kinase kinase kinase, ANP1, which initiates a phosphorylation cascade involving two stress MAPKs, AtMPK3 and AtMPK6. Constitutively active ANP1 mimics the H(2)O(2) effect and initiates the MAPK cascade that induces specific stress-responsive genes, but it blocks the action of auxin, a plant mitogen and growth hormone. The latter observation provides a molecular link between oxidative stress and auxin signal transduction. Finally, we show that transgenic tobacco plants that express a constitutively active tobacco ANP1 orthologue, NPK1, display enhanced tolerance to multiple environmental stress conditions without activating previously described drought, cold, and abscisic acid signaling pathways. Thus, manipulation of key regulators of an oxidative stress signaling pathway, such as ANP1/NPK1, provides a strategy for engineering multiple stress tolerance that may greatly benefit agriculture.

In higher plants, MAP kinase cascades are involved in the transduction of numerous stress-related signals but much less is known about the effect of mitogenic signals. We have analysed MAP kinase activation in tobacco cells after treatment by auxin, a growth factor required at physiological concentrations for mitosis in plant cell cultures. From in-gel assay of myelin basic protein kinase and from immunochemical detection of ERK related kinases, we show that the mitogenic effect of auxin, which was confirmed by the specific increase of several mRNAs species, did not rely on MAP kinase activation within the first 2 hours. These data contest previous results which could be due to the activation of MAP kinase by a signal other than auxin. In the second part of this study, we show that the treatment of the cells with high concentrations of various weak lipophilic acids such as auxin, in a nonphysiological concentration range, butyric or acetic acid is sufficient to activate transiently a MAP kinase. The data show that MAP kinase activation is the consequence of cytosolic acidification. Moreover, it is not sensitive to the protein kinase inhibitor staurosporine. These results suggest a functional role for cytosolic acidification as a second messenger mediating MAP kinase activation in the response of plant cells to various stresses.