Major depression associated with a levonorgestrel-releasing intrauterine system mimicking frontotemporal dementia: a case report.

This case illustrates the adverse cognitive and affective effects associated with the use of an intrauterine hormonal contraceptive, which could be confused with symptoms of early onset dementia. We present a case of a 42-year-old woman diagnosed with seronegative spondyloarthropathy who subsequently developed anxiety and depressive symptoms after the implantation of a Levonorgestrel-Releasing Intrauterine System (LNG-IUS). Three years later, she began to experience memory and attentional failures, refractory pain, and severe depression. The progression of psychiatric symptoms led to a diagnosis of bipolar affective disorder and treatment with antidepressants and anxiolytics. Due to cognitive and psychiatric symptoms, autoimmune encephalitis was considered, but no improvement was shown with treatment. Early onset dementia was suspected, and a brain PET scan revealed frontal lobe hypometabolism. An adverse effect of LNG-IUS was considered; after its removal, mood and cognitive function improvements were observed. This case report emphasizes the importance of considering organic causes of unexplained psychiatric manifestations and highlights the potential impact of hormonal interventions on mental health.

Prepandemic viral community-acquired pneumonia: Diagnostic sensitivity and specificity of nasopharyngeal swabs and performance of clinical severity scores.

The objectives of this work were to assess the diagnostic sensitivity and specificity of nasopharyngeal (NP) swabs for viral community-acquired pneumonia (CAP) and the performance of pneumonia severity index (PSI) and CURB-65 severity scores in the viral CAP in adults. A prospective observational cohort study of consecutive 341 hospitalized adults with CAP was performed between January 2018 and March 2020. Demographics, comorbidities, symptoms/signs, analytical data, severity scores, antimicrobials, and outcomes were recorded. Blood, NP swabs, sputum, and urine samples were collected at admission and assayed by multiplex real time-PCR, bacterial cultures, and Streptococcus pneumoniae and Legionella pneumophila antigens detection, to determine the etiologies and quantify the viral load. The etiology was identified in 174 (51.0%) patients, and in 85 (24.9%) it was viral, the most frequent rhinovirus and influenza virus. The sensitivity of viral detection in sputum (50.7%) was higher than in NP swabs (20.9%). Compared with sputum, the positive predictive value and specificity of NP swabs for viral diagnosis were 95.8% and 96.9%, respectively. Performance of PSI and CURB-65 scores in all CAP with etiologic diagnosis were as expected, with mortality associated with higher values, but they were not associated with mortality in patients with viral pneumonia. NP swabs have lower sensitivity but high specificity for the diagnosis of viral CAP in adults compared with sputum, reinforcing the use NP swabs for the diagnostic etiology work-up. The PSI and CURB-65 scores did not predict mortality in the viral CAP, suggesting that they need to be updated scores based on the identification of the etiological agent.

Clinical and Ecological Impact of an Educational Program to Optimize Antibiotic Treatments in Nursing Homes (PROA-SENIOR): A Cluster, Randomized, Controlled Trial and Interrupted Time-Series Analysis.

BACKGROUND: Antimicrobial stewardship programs (ASPs) are recommended in nursing homes (NHs), although data are limited. We aimed to determine the clinical and ecological impact of an ASP for NHs. METHODS: We performed a cluster, randomized, controlled trial and a before-after study with interrupted time-series analyses in 14 NHs for 30 consecutive months from July 2018 to December 2020 in Andalusia, Spain. Seven facilities implemented an ASP with a bundle of 5 educational measures (general ASP) and 7 added 1-to-1 educational interviews (experimental ASP). The primary outcome was the overall use of antimicrobials, calculated monthly as defined daily doses (DDD) per 1000 resident days (DRD). RESULTS: The total mean antimicrobial consumption decreased by 31.2% (-16.72 DRD; P = .045) with respect to the preintervention period; the overall use of quinolones and amoxicillin-clavulanic acid dropped by 52.2% (P = .001) and 42.5% (P = .006), respectively; and the overall prevalence of multidrug-resistant organisms (MDROs) decreased from 24.7% to 17.4% (P = .012). During the intervention period, 12.5 educational interviews per doctor were performed in the experimental ASP group; no differences were found in the total mean antimicrobial use between groups (-14.62 DRD; P = .25). Two unexpected coronavirus disease 2019 waves affected the centers increasing the overall mean use of antimicrobials by 40% (51.56 DRD; P < .0001). CONCLUSIONS: This study suggests that an ASP for NHs appears to be associated with a decrease in total consumption of antimicrobials and prevalence of MDROs. This trial did not find benefits associated with educational interviews, probably due to the coronavirus disease 2019 pandemic. Clinical Trials Registration. NCT03543605.

17-ß Estradiol up-regulates energy metabolic pathways, cellular proliferation and tumor invasiveness in ER+ breast cancer spheroids.

Several biological processes related to cancer malignancy are regulated by 17-ß estradiol (E2) in ER+-breast cancer. To establish the role of E2 on the atypical cancer energy metabolism, a systematic study analyzing transcription factors, proteins, and fluxes associated with energy metabolism was undertaken in multicellular tumor spheroids (MCTS) from human ER+ MCF-7 breast cancer cells. At E2 physiological concentrations (10 and 100 nM for 24 h), both ERα and ERß receptors, and their protein target pS2, increased by 0.6-3.5 times vs. non-treated MCTS, revealing an activated E2/ER axis. E2 also increased by 30-470% the content of several transcription factors associated to mitochondrial biogenesis and oxidative phosphorylation (OxPhos) (p53, PGC1-α) and glycolytic pathways (HIF1-α, c-MYC). Several OxPhos and glycolytic proteins (36-257%) as well as pathway fluxes (48-156%) significantly increased being OxPhos the principal ATP cellular supplier (>75%). As result of energy metabolism stimulation by E2, cancer cell migration and invasion processes and related proteins (SNAIL, FN, MM-9) contents augmented by 24-189% vs. non-treated MCTS. Celecoxib at 10 nM blocked OxPhos (60%) as well as MCTS growth, cell migration and invasiveness (>40%); whereas the glycolytic inhibitor iodoacetate (0.5 µM) and doxorubicin (70 nM) were innocuous. Our results show for the first time using a more physiological tridimensional cancer model, resembling the initial stages of solid tumors, that anti-mitochondrial therapy may be useful to deter hormone-dependent breast carcinomas.

Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection.

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2 infection induces an exacerbated inflammation driven by innate immunity components. Dendritic cells (DCs) play a key role in the defense against viral infections, for instance plasmacytoid DCs (pDCs), have the capacity to produce vast amounts of interferon-alpha (IFN-α). In COVID-19 there is a deficit in DC numbers and IFN-α production, which has been associated with disease severity. In this work, we described that in addition to the DC deficiency, several DC activation and homing markers were altered in acute COVID-19 patients, which were associated with multiple inflammatory markers. Remarkably, previously hospitalized and nonhospitalized patients remained with decreased numbers of CD1c+ myeloid DCs and pDCs seven months after SARS-CoV-2 infection. Moreover, the expression of DC markers such as CD86 and CD4 were only restored in previously nonhospitalized patients, while no restoration of integrin ß7 and indoleamine 2,3-dyoxigenase (IDO) levels were observed. These findings contribute to a better understanding of the immunological sequelae of COVID-19.

Prevalence and Risk Factors for Multidrug-Resistant Organisms Colonization in Long-Term Care Facilities Around the World: A Review.

Elderly people confined to chronic care facilities face an increased risk of acquiring infections by multidrug-resistant organisms (MDROs). This review presents the current knowledge of the prevalence and risk factors for colonization by MDROs in long-term care facilities (LTCF), thereby providing a useful reference to establish objectives for implementing successful antimicrobial stewardship programs (ASPs). We searched in PubMed and Scopus for studies examining the prevalence of MDROs and/or risk factors for the acquisition of MDROs in LTCF. One hundred and thirty-four studies published from 1987 to 2020 were included. The prevalence of MDROs in LTCF varies between the different continents, where Asia reported the highest prevalence of extended-spectrum ß-lactamase (ESBL) Enterobacterales (71.6%), carbapenem resistant (CR) Enterobacterales (6.9%) and methicillin-resistant Staphylococcus aureus (MRSA) (25.6%) and North America the highest prevalence to MDR Pseudomonas aeruginosa (5.4%), MDR Acinetobacter baumannii (15.0%), vancomycin-resistant Enterococcus spp. (VRE) (4.0%), and Clostridioides difficile (26.1%). Furthermore, MDRO prevalence has experienced changes over time, with increases in MDR P. aeruginosa and extended spectrum ß-lactamase producing Enterobacterales observed starting in 2015 and decreases of CR Enterobacterales, MDR A. baumannii, VRE, MRSA and C. difficile. Several risk factors have been found, such as male sex, chronic wounds, the use of medical devices, and previous antibiotic use. The last of these aspects represents one of the most important modifiable factors for reducing colonization with MDROs through implementing ASPs in LTCF.

Are antimicrobial stewardship interventions effective and safe in long-term care facilities? A systematic review and meta-analysis.

BACKGROUND: Long-term care facilities (LTCFs) are health-care settings with high antimicrobial consumption and hence need to develop effective antimicrobial stewardship programmes (ASPs). OBJECTIVE: To assess the effects of ASPs on care-related, clinical and ecological outcomes in LTCFs. METHODS: Data sources were PubMed, EMBASE, CINAHL and SCOPUS. Study eligibility criteria were original research articles (controlled clinical trials or controlled before and after studies) published up to 1 October 2020. Participants were adult residents of LTCFs, residential aged-care facilities, nursing homes, veterans' homes, skilled nursing facilities and assisted living facilities for older people. Interventions included ASPs versus standard care. Outcomes assessed were antimicrobial consumption and appropriateness, infections, hospital admissions and mortality. Available data were pooled in a meta-analysis, and inconsistency between studies was evaluated using the I2 statistic. Certainty of evidence was assessed using the GRADE approach. RESULTS: Of the 3111 papers identified, 12 studies met the inclusion criteria. All of them analysed the impact of interventions on antimicrobial use based on consumption-related variables (n = 8) and/or percentage of inappropriate prescriptions (n = 6). Pooled data showed a mean difference of -0.47 prescriptions per 1000 resident-days in favour of ASPs (95% CI -0.87 to -0.07, I2 = 71%). Five studies analysed the clinical effect of ASPs on the number of hospital admissions and/or resident mortality. The meta-analysis showed a mean difference of 0.17 hospital admissions per 1000 resident-days (95% CI -0.07 to 0.41, I2 = 17%) and a mean difference of -0.02 deaths per 1000 resident-days (95% CI -0.14 to 0.09, I2 = 0%). Only two studies included infections as a study outcome. CONCLUSIONS: ASPs appear to improve antimicrobial use in this setting without increasing hospital admissions or deaths, indicating that these programmes do not lead to under-treatment of infections. Nonetheless, further higher-quality clinical trials are required to understand the effects of ASPs in LTCFs. PROSPERO REGISTRATION NUMBER: CRD42021225127.

SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome.

The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient's hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome.

Normal pressure hydrocephalus: Diagnostic delay. / Hidrocefalia de presión normal: demora en el diagnóstico

INTRODUCTION: Normotensive hydrocephalus is a differential diagnosis in the evaluation of the dementia syndrome. The diagnostic protocols would allow detecting this pathology that has more effective treatment than other dementias. OBJECTIVE: To describe a population with clinical suspicion of normal pressure hydrocephalus evaluated in a Colombian psychiatric hospital and discuss the possible reasons for its diagnostic and therapeutic delay. MATERIALS AND METHODS: We conducted a retrospective study of medical records to identify patients with suspected normal pressure hydrocephalus during a 5-year period. RESULTS: Thirty-five patients with suspected normal pressure hydrocephalus underwent diagnostic lumbar puncture and five of them were considered candidates for a peritonealvenous shunt, but none underwent this surgical procedure. After three to six months of the lumbar puncture, the gait pattern improved in 22.8% of the patients, cognition in 22.8%, and sphincter control in 11.4%. Improvement was not sustained in the long term (1 year) in any of them. CONCLUSION: This study suggests the poor implementation of the protocols for evaluating patients with cognitive deficits and delays in the diagnosis of normal pressure hydrocephalus. A small number of patients were identified as candidates for treatment. Normal pressure hydrocephalus is a potentially reversible clinical entity with the placement of a peritoneal ventricular shunt, but delays in diagnosis and treatment have deleterious consequences for patients and their families.

Introducción. La hidrocefalia normotensiva es un diagnóstico diferencial en la evaluación del síndrome demencial. Los protocolos diagnósticos permitirían detectar esta condición, cuyo tratamiento es más efectivo que el de otras demencias. Objetivo. Describir una población con sospecha clínica de hidrocefalia normotensiva evaluada en un hospital psiquiátrico colombiano y discutir las posibles razones de la demora en el diagnóstico y en la terapia de esta condición clínica. Materiales y métodos. Se hizo un estudio retrospectivo de los registros médicos para detectar pacientes con sospecha de hidrocefalia normotensiva durante un período de cinco años. Resultados. A 35 pacientes con sospecha de hidrocefalia normotensiva se les hizo una punción lumbar diagnóstica. Cinco de ellos se consideraron candidatos para una derivación ventrículo-peritoneal, pero ninguno se sometió a este procedimiento quirúrgico. A los 3-6 meses de la punción lumbar, se observó una mejoría del patrón de la marcha en el 22,8 % de los pacientes, de la cognición en el 22,8 % y del control del esfínter en el 11,4 %. La mejoría no se mantuvo a largo plazo (un año) en ningún paciente. Conclusión. Se encontró una implementación deficiente de los protocolos de evaluación de los pacientes con déficit cognitivos y demoras en el diagnóstico de la hidrocefalia normotensiva, así como un número reducido de pacientes clasificados como candidatos para el tratamiento. La hidrocefalia normotensiva es una condición clínica potencialmente reversible con la colocación de una derivación ventrículo-peritoneal. Los retrasos en el diagnóstico y en el tratamiento tienen consecuencias perjudiciales para los pacientes y sus familias.

Normal pressure hydrocephalus: Diagnostic delay / Hidrocefalia de presión normal: demora en el diagnóstico

Abstract. Introduction: Normotensive hydrocephalus is a differential diagnosis in the evaluation of the dementia syndrome. The diagnostic protocols would allow detecting this pathology that has more effective treatment than other dementias. Objective: To describe a population with clinical suspicion of normal pressure hydrocephalus evaluated in a Colombian psychiatric hospital and discuss the possible reasons for its diagnostic and therapeutic delay. Materials and methods: We conducted a retrospective study of medical records to identify patients with suspected normal pressure hydrocephalus during a 5-year period. Results: Thirty-five patients with suspected normal pressure hydrocephalus underwent diagnostic lumbar puncture and five of them were considered candidates for a peritoneal-venous shunt, but none underwent this surgical procedure. After three to six months of the lumbar puncture, the gait pattern improved in 22.8% of the patients, cognition in 22.8%, and sphincter control in 11.4%. Improvement was not sustained in the long term (1 year) in any of them. Conclusion: This study suggests the poor implementation of the protocols for evaluating patients with cognitive deficits and delays in the diagnosis of normal pressure hydrocephalus. A small number of patients were identified as candidates for treatment. Normal pressure hydrocephalus is a potentially reversible clinical entity with the placement of a peritoneal ventricular shunt, but delays in diagnosis and treatment have deleterious consequences for patients and their families.

Resumen. Introducción. La hidrocefalia normotensiva es un diagnóstico diferencial en la evaluación del síndrome demencial. Los protocolos diagnósticos permitirían detectar esta condición, cuyo tratamiento es más efectivo que el de otras demencias. Objetivo. Describir una población con sospecha clínica de hidrocefalia normotensiva evaluada en un hospital psiquiátrico colombiano y discutir las posibles razones de la demora en el diagnóstico y en la terapia de esta condición clínica. Materiales y métodos. Se hizo un estudio retrospectivo de los registros médicos para detectar pacientes con sospecha de hidrocefalia normotensiva durante un período de cinco años. Resultados. A 35 pacientes con sospecha de hidrocefalia normotensiva se les hizo una punción lumbar diagnóstica. Cinco de ellos se consideraron candidatos para una derivación ventrículo-peritoneal, pero ninguno se sometió a este procedimiento quirúrgico. A los 3-6 meses de la punción lumbar, se observó una mejoría del patrón de la marcha en el 22,8 % de los pacientes, de la cognición en el 22,8 % y del control del esfínter en el 11,4 %. La mejoría no se mantuvo a largo plazo (un año) en ningún paciente. Conclusión. Se encontró una implementación deficiente de los protocolos de evaluación de los pacientes con déficit cognitivos y demoras en el diagnóstico de la hidrocefalia normotensiva, así como un número reducido de pacientes clasificados como candidatos para el tratamiento. La hidrocefalia normotensiva es una condición clínica potencialmente reversible con la colocación de una derivación ventrículo-peritoneal. Los retrasos en el diagnóstico y en el tratamiento tienen consecuencias perjudiciales para los pacientes y sus familias.

Clinical impact of an educational antimicrobial stewardship program associated with infectious diseases consultation targeting patients with cancer: Results of a 9-year quasi-experimental study with an interrupted time-series analysis.

OBJECTIVES: Antibiotic stewardship programs (ASP) have already demonstrated clinical benefits. However, their effectiveness or safety in immunocompromised hosts needs to be proved. METHODS: An ecologic quasi-experimental study was performed from January 2009 to June 2017 in the Oncology department of a tertiary-care hospital. A stable program of Infectious Diseases consultation (IDC) already existed at this unit, and an educational ASP was added in 2011. Its main intervention consisted of face-to-face educational interviews. Antibiotic consumption was assessed through quarterly Defined Daily Doses (DDD) per 100 occupied bed-days. Mortality was evaluated in patients with bloodstream infections through the quarterly incidence density per 1000 admissions, and the annual mortality rates at 7 and 30-days. Time-trends were analysed through segmented-regression analysis, and the impact of the ASP was assessed through before-after interrupted time-series analysis. RESULTS: Mortality significantly decreased throughout the study period (-13.3% annual reduction for 7-day mortality rate, p < 0.01; -8.1% annual reduction for 30-day mortality, p = 0.03), parallel to a reduction in antibiotic consumption (quarterly reduction -0.4%, p = 0.01), especially for broader-spectrum antibiotics. The before-after study settled a significant inflexion point on the ASP implementation for the reduction of antibiotic consumption (change in level 0.95 DDD, p = 0.71; change in slope -1.98 DDD per quarter, p < 0.01). The decreasing trend for mortality before the ASP also continued after its implementation. CONCLUSIONS: The combination of an ASP with IDC improved antibiotic use among patients with cancer, and was accompanied by a reduction of mortality of bacteraemic infections. Implementation of the ASP was necessary to effectively change antibiotic use.

Sinorhizobium fredii HH103 RirA Is Required for Oxidative Stress Resistance and Efficient Symbiosis with Soybean.

Members of Rhizobiaceae contain a homologue of the iron-responsive regulatory protein RirA. In different bacteria, RirA acts as a repressor of iron uptake systems under iron-replete conditions and contributes to ameliorate cell damage during oxidative stress. In Rhizobium leguminosarum and Sinorhizobium meliloti, mutations in rirA do not impair symbiotic nitrogen fixation. In this study, a rirA mutant of broad host range S. fredii HH103 has been constructed (SVQ780) and its free-living and symbiotic phenotypes evaluated. No production of siderophores could be detected in either the wild-type or SVQ780. The rirA mutant exhibited a growth advantage under iron-deficient conditions and hypersensitivity to hydrogen peroxide in iron-rich medium. Transcription of rirA in HH103 is subject to autoregulation and inactivation of the gene upregulates fbpA, a gene putatively involved in iron transport. The S. fredii rirA mutant was able to nodulate soybean plants, but symbiotic nitrogen fixation was impaired. Nodules induced by the mutant were poorly infected compared to those induced by the wild-type. Genetic complementation reversed the mutant's hypersensitivity to H2O2, expression of fbpA, and symbiotic deficiency in soybean plants. This is the first report that demonstrates a role for RirA in the Rhizobium-legume symbiosis.

Neurosífilis: un problema antiguo que no pierde actualidad / Neurosyphilis: an Age-old Problem that is Still Relevant Today

Resumen La neurosífilis es una presentación clínica de la sífilis y puede suceder en estadios tempranos o tardíos de la infección. Aunque el tratamiento específico para todas las formas clínicas de la sífilis existe desde hace mucho tiempo, los estadios avanzados de la enfermedad aún son prevalentes, con las secuelas neurológicas irreversibles que ocasionan. Este artículo revisa la evidencia actual, los métodos diagnósticos y el tratamiento específico para la sífilis terciaria.

Abstract Neurosyphilis is the clinical manifestation of syphilis that can arise during either the early or late stages of infection. Even though dedicated treatment for all clinical forms of syphilis has been available for many years, the advanced stages of the disease are still prevalent, with irreversible sequelae. This article reviews the current evidence, diagnostic methods and specific treatment for tertiary syphilis.

[Neurosyphilis: an Age-old Problem that is Still Relevant Today]. / Neurosífilis: un problema antiguo que no pierde actualidad.

Neurosyphilis is the clinical manifestation of syphilis that can arise during either the early or late stages of infection. Even though dedicated treatment for all clinical forms of syphilis has been available for many years, the advanced stages of the disease are still prevalent, with irreversible sequelae. This article reviews the current evidence, diagnostic methods and specific treatment for tertiary syphilis.

Exopolysaccharide Production by Sinorhizobium fredii HH103 Is Repressed by Genistein in a NodD1-Dependent Manner.

In the rhizobia-legume symbiotic interaction, bacterial surface polysaccharides, such as exopolysaccharide (EPS), lipopolysaccharide (LPS), K-antigen polysaccharide (KPS) or cyclic glucans (CG), appear to play crucial roles either acting as signals required for the progression of the interaction and/or preventing host defence mechanisms. The symbiotic significance of each of these polysaccharides varies depending on the specific rhizobia-legume couple. In this work we show that the production of exopolysaccharide by Sinorhizobium fredii HH103, but not by other S. fredii strains such as USDA257 or NGR234, is repressed by nod gene inducing flavonoids such as genistein and that this repression is dependent on the presence of a functional NodD1 protein. In agreement with the importance of EPS for bacterial biofilms, this reduced EPS production upon treatment with flavonoids correlates with decreased biofilm formation ability. By using quantitative RT-PCR analysis we show that expression of the exoY2 and exoK genes is repressed in late stationary cultures of S. fredii HH103 upon treatment with genistein. Results presented in this work show that in S. fredii HH103 EPS production is regulated just in the opposite way than other bacterial signals such as Nod factors and type 3 secreted effectors: it is repressed by flavonoids and NodD1 and enhanced by the nod repressor NolR. These results are in agreement with our previous observations showing that lack of EPS production by S. fredii HH103 is not only non-detrimental but even beneficial for symbiosis with soybean.

The Sinorhizobium fredii HH103 Genome: A Comparative Analysis With S. fredii Strains Differing in Their Symbiotic Behavior With Soybean.

Sinorhizobium fredii HH103 is a fast-growing rhizobial strain infecting a broad range of legumes including both American and Asiatic soybeans. In this work, we present the sequencing and annotation of the HH103 genome (7.25 Mb), consisting of one chromosome and six plasmids and representing the structurally most complex sinorhizobial genome sequenced so far. Comparative genomic analyses of S. fredii HH103 with strains USDA257 and NGR234 showed that the core genome of these three strains contains 4,212 genes (61.7% of the HH103 genes). Synteny plot analysis revealed that the much larger chromosome of USDA257 (6.48 Mb) is colinear to the HH103 (4.3 Mb) and NGR324 chromosomes (3.9 Mb). An additional region of the USDA257 chromosome of about 2 Mb displays similarity to plasmid pSfHH103e. Remarkable differences exist between HH103 and NGR234 concerning nod genes, flavonoid effect on surface polysaccharide production, and quorum-sensing systems. Furthermore a number of protein secretion systems have been found. Two genes coding for putative type III-secreted effectors not previously described in S. fredii, nopI and gunA, have been located on the HH103 genome. These differences could be important to understand the different symbiotic behavior of S. fredii strains HH103, USDA257, and NGR234 with soybean.

The market triumph of ecotourism: an economic investigation of the private and social benefits of competing land uses in the Peruvian Amazon.

Annual revenue flow to developing countries for ecotourism (or nature-based tourism) could be as large as US$ 210×10(12), providing an enormous financial incentive against habitat loss and exploitation. However, is ecotourism the most privately and/or socially valuable use of rainforest land? The question is rarely answered because the relevant data, estimates of profits and fixed costs, are rarely available. We present a social cost-benefit analysis of land use in an ecotourism cluster in the Tambopata region of Amazonian Peru. The net present value of ecotourism-controlled land is given by the producer surplus (profits plus fixed costs of ecotourism lodges): US$ 1,158 ha(-1), which is higher than all currently practiced alternatives, including unsustainable logging, ranching, and agriculture. To our knowledge, this is the first sector-wide study of profitability and producer surplus in a developing-country ecotourism sector and the first to compare against equivalent measures for a spectrum of alternative uses. We also find that ecotourism-controlled land sequesters between 5.3 to 8.7 million tons of above-ground carbon, which is equivalent to between 3000-5000 years of carbon emissions from the domestic component of air and surface travel between the gateway city of Cusco and the lodges, at 2005 emission rates. Ecotourism in Tambopata has successfully monetized the hedonic value of wild nature in Amazonian Peru, and justifies the maintenance of intact rainforest over all alternative uses on narrow economic grounds alone.

Mutation in the cobO gene generates auxotrophy for cobalamin and methionine and impairs the symbiotic properties of Sinorhizobium fredii HH103 with soybean and other legumes.

We report here the isolation of a methionine and cobalamin mutant strain (SVQ336) of Sinorhizobium fredii HH103 obtained by Tn5-lacZ mutagenesis. Sequence analysis showed that the transposon was inserted into a gene homologous to cobO. This gene codes for a cobalamin adenosyltransferase which is involved in the biosynthesis of vitamin B12. Another HH103 cobO mutant (strain SVQ524), was constructed by the insertion of Omega interposon. Both cobO mutants required the addition of methionine because cobalamin acts as a cofactor of the enzyme MetH, which catalyses the last step of the methionine biosynthesis. Mutant SVQ524 failed to nodulate on Vigna radiate but was able to nodulate on Glycine max cvs. Williams and Peking and Cajanus cajan, although the total number of nodules formed was highly reduced in comparison with that of plants inoculated with the wild-type strain HH103. The roots of these plants did not seem to secrete enough cobalamin and/or methionine to support growth of cobalamin/methionine auxotrophs in the rhizosphere. In all cases, the phenotype of SVQ524 was nearly overcome by the addition of methionine or cobalamin to the plant growth media or by the presence of a copy of the cobO gene in cosmid pMUS756.