Mathematical Modeling of Photo- and Thermomorphogenesis in Plants

Increased day lengths and warm conditions inversely affect plant growth by directly modulating nuclear phyB, ELF3, and COP1 levels. Quantitative measures of the hypocotyl length have been key to gaining a deeper understanding of this complex regulatory network, while similar quantitative data are the foundation for many studies in plant biology. Here, we explore the application of mathematical modeling, specifically ordinary differential equations (ODEs), to understand plant responses to these environmental cues. We provide a comprehensive guide to constructing, simulating, and fitting these models to data, using the law of mass action to study the evolution of molecular species. The fundamental principles of these models are introduced, highlighting their utility in deciphering complex plant physiological interactions and testing hypotheses. This brief introduction will not allow experimentalists without a mathematical background to run their own simulations overnight, but it will help them grasp modeling principles and communicate with more theory-inclined colleagues.

COP1 dynamics integrate conflicting seasonal light and thermal cues in the control of Arabidopsis elongation

As the summer approaches, plants experience enhanced light inputs and warm temperatures, two environmental cues with an opposite morphogenic impact. Key components of this response are PHYTOCHROME B (phyB), EARLY FLOWERING 3 (ELF3), and CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1). Here, we used single and double mutant/overexpression lines to fit a mathematical model incorporating known interactions of these regulators. The fitted model recapitulates thermal growth of all lines used and correctly predicts thermal behavior of others not used in the fit. While thermal COP1 function is accepted to be independent of diurnal timing, our model shows that it acts at temperature signaling only during daytime. Defective response of cop1-4 mutants is epistatic to phyB-9 and elf3-8, indicating that COP1 activity is essential to transduce phyB and ELF3 thermosensory function. Our thermal model provides a unique toolbox to identify best allelic combinations enhancing climate change resilience of crops adapted to different latitudes.

Hysteresis in PHYTOCHROME-INTERACTING FACTOR 4 and EARLY-FLOWERING 3 dynamics dominates warm daytime memory in Arabidopsis

Despite the identification of temperature sensors and downstream components involved in promoting stem growth by warm temperatures, when and how previous temperatures affect current plant growth remain unclear. Here we show that hypocotyl growth in Arabidopsis thaliana during the night responds not only to the current temperature but also to preceding daytime temperatures, revealing a short-term memory of previous conditions. Daytime temperature affected the levels of PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) and LONG HYPOCOTYL 5 (HY5) in the nucleus during the next night. These factors jointly accounted for the observed growth kinetics, whereas nighttime memory of prior daytime temperature was impaired in pif4 and hy5 mutants. PIF4 promoter activity largely accounted for the temperature-dependent changes in PIF4 protein levels. Notably, the decrease in PIF4 promoter activity triggered by cooling required a stronger temperature shift than the increase caused by warming, representing a typical hysteretic effect; this hysteretic pattern required EARLY-FLOWERING 3 (ELF3). Warm temperatures promoted the formation of nuclear condensates of ELF3 in hypocotyl cells during the afternoon but not in the morning. These nuclear speckles showed poor sensitivity to subsequent cooling. We conclude that ELF3 achieves hysteresis and drives the PIF4 promoter into the same behavior, enabling a short-term memory of daytime temperature conditions.

Regulation of COP1 Function by Brassinosteroid Signaling

Small increases in temperature result in enhanced elongation of the hypocotyl and petioles and hyponastic growth, in an adaptive response directed to the cooling of the leaves and to protect the shoot meristem from the warm soil. This response, collectively termed as thermomorphogenesis, relies on the faster reversion of phyB Pfr at warmer temperatures, which leads to enhanced activity of the basic-helix-loop-helix PHYTOCHROME INTERACTING FACTOR 4 (PIF4). PIF4 acts as a molecular hub integrating light and temperature cues with endogenous hormonal signaling, and drives thermoresponsive growth by directly activating auxin synthesis and signaling genes. Growth promotion by PIF4 depends on brassinosteroid (BR) signaling, as indicated by the impaired thermoresponse of BR-defective mutants and the partial restoration of pifq thermoresponsive defects by brassinolide (BL) application. Also, phyB limits thermomorphogenic elongation through negative regulation of the E3 ubiquitin ligase COP1 that triggers nuclear degradation of multiple photomorphogenesis-promoting factors acting antagonistically to PIF4. COP1 is indeed observed to accumulate in the nucleus in darkness, or in response to warm temperatures, with constitutive photomorphogenic cop1 mutants failing to respond to temperature. Here we explored the role of BR signaling on COP1 function, by growing cop1 seedlings on BL or the inhibitor brassinazole (BRZ), under different light and temperature regimes. We show that weak cop1 alleles exhibit a hyposensitive response to BL. Furthermore, while cop1-6 mutants display as described a wild-type response to temperature in continuous darkness, this response is abolished by BRZ. Application of this inhibitor likewise suppressed temperature-induced COP1 nuclear accumulation in N. benthamiana leaves. Overall these results demonstrate that cop1-6 is not a temperature-conditional allele, but this mutation allows for a partially active protein which unveils a pivotal role of active BR signaling in the control of COP1 activity.

The dream school: Mind-changing perspectives of people with intellectual disabilities

In this study, we analyse the characteristics that define an ideal school, from the perspective of people with intellectual disabilities. we carried out an inclusive research qualitative study with 36 Spanish adults with intellectual disabilities. Information from individual interviews about educational inclusion was summarized on to notecards, allowing participants to place messages into categories on a poster board. Identified themes included facilities and resources; values and rules; intimidation; what students learn; how students learn best; exams; teachers; and classmates. Results highlight the importance of inclusive values and the need for a curriculum that meets the needs of all students.

Convergent regulation of PIFs and the E3 ligase COP1/SPA1 mediates thermosensory hypocotyl elongation by plant phytochromes

The ability of plants to sense and integrate daily and seasonal changes in light and temperature and to adjust their growth and development accordingly, is critical to withstand severe weather oscillations in a year. While molecular mechanisms controlling light responses are relatively well established, those involved in the perception and response to temperature are just beginning to be understood. Phytochromes emerged as major temperature sensors; due to warmer temperatures accelerate the dark reversal reaction to the Pr inactive state. Downstream of phytochromes, the bHLH Phytochrome Interacting Factors, and in particular PIF4, act as central signaling hubs to growth coordination in response to light and temperature cues, and to the gibberellin and brassinosteroid pathways. Here we discuss recent findings showing that phytochromes control PIFs activity not only by signaling their destruction in the light, but by modulating transcriptional repression of these factors by the circadian clock. Together with this repression, phytochromes inactivate the COP1/SPA ubiquitin ligase, which negatively regulates light signaling through degradation of a large set of nuclear photomorphogenesis-promoting factors that suppress PIFs activity.

Genitourinary syndrome of menopause. Prevalence and quality of life in Spanish postmenopausal women. The GENISSE study

OBJECTIVE

To determine the prevalence of genitourinary syndrome of menopause (GSM) and urogynecological conditions associated with menopause, and to evaluate the impact of GSM on quality of life in a cohort of Spanish postmenopausal women.

METHODS

Multicenter, cross-sectional, and observational study involving 430 women.

RESULTS

The prevalence of GSM was 70%. GSM was diagnosed in 60.2% of women with no known diagnosis of vulvovaginal atrophy or GSM. Most prevalent symptoms were vaginal dryness (93.3%) and reduced lubrication with sexual activity (90.0%). Most prevalent signs were decreased moisture (93.7%) and loss of vaginal rugae (78.4%). GSM was significantly associated with stress or mixed urinary incontinence, overactive bladder, and vaginal prolapse. Symptoms showed a low-moderate impact on quality of life, mainly in sexual functioning and self-concept and body image.

CONCLUSIONS

The GSM is very prevalent in Spanish postmenopausal women, affecting up to 70% of those consulting the gynecologist. Despite the high prevalence of symptoms and signs and its impact on the women's well-being, GSM remains underdiagnosed and undertreated. Given its relationship with urogynecological conditions, it seems necessary to provide an adequate evaluation of postmenopausal women for identifying potential co-morbidities and providing most adequate treatments. An adequate management of GSM will contribute to an improvement in the quality of life of these women.

Relationships between atypical sensory processing patterns, maladaptive behaviour and maternal stress in Spanish children with autism spectrum disorder

BACKGROUND

This study investigated sensory processing in a sample of Spanish children with autism spectrum disorder (ASD). Specifically, the study aimed to explore (1) the prevalence and distribution of atypical sensory processing patterns, (2) the relationship between adaptive and maladaptive behaviour with atypical sensory processing and (3) the possible relationship between sensory subtype and maternal stress.

METHODS

The short sensory profile 2 (Dunn 2014) and the vineland adaptive behavior scale (Sparrow et al. 1984) were administered to examine the sensory processing difficulties and maladaptive behaviours of 45 children with ASD aged 3 to 14; their mothers also completed the parenting stress index-short form (Abidin 1995).

RESULTS

Atypical sensory features were found in 86.7% of the children; avoider and sensor being the two most common patterns. No significant relationship was found between atypical sensory processing and adaptive behaviour. However, the analysis showed a strong relationship between sensory processing and maladaptive behaviour. Both maladaptive behaviour and sensory processing difficulties correlated significantly with maternal stress although maternal stress was predicted only by the sensory variable, and in particular by the avoider pattern.

CONCLUSIONS

The findings suggest that sensory features in ASD may be driving the high prevalence of parental stress in carers. They also suggest that the effect on parental stress that has been attributed traditionally to maladaptive behaviours may be driven by sensory difficulties. The implications of these findings are discussed in relation to the development of interventions and the need to explore contextual and cultural variables as possible sources of variability.

Perception and signalling of light and temperature cues in plants

Light and temperature patterns are often correlated under natural plant growth conditions. In this review, we analyse the perception and signalling mechanisms shared by both these environmental cues and discuss the functional implications of their convergence to control plant growth. The first point of integration is the phytochrome B (phyB) receptor, which senses light and temperature. Downstream of phyB, the signalling core comprises two branches, one involving PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and the other CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) and ELONGATED HYPOCOTYL 5 (HY5). The dynamics of accumulation and/or localization of each of these core signalling components depend on light and temperature conditions. These pathways are connected through COP1, which enhances the activity of PIF4. The circadian clock modulates this circuit, since EARLY FLOWERING 3 (ELF3), an essential component of the evening complex (EC), represses expression of the PIF4 gene and PIF4 transcriptional activity. Phytochromes are probably not the only entry point of temperature into this network, but other sensors remain to be established. The sharing of mechanisms of action for two distinct environmental cues is to some extent unexpected, as it renders these responses mutually dependent. There are nonetheless many ecological contexts in which such a mutual influence could be beneficial.

New Rimocidin/CE-108 Derivatives Obtained by a Crotonyl-CoA Carboxylase/Reductase Gene Disruption in Streptomyces diastaticus var. 108: Substrates for the Polyene Carboxamide Synthase PcsA

The rimJ gene, which codes for a crotonyl-CoA carboxylase/reductase, lies within the biosynthetic gene cluster for two polyketides belonging to the polyene macrolide group (CE-108 and rimocidin) produced by Streptomyces diastaticus var. 108. Disruption of rimJ by insertional inactivation gave rise to a recombinant strain overproducing new polyene derivatives besides the parental CE-108 (2a) and rimocidin (4a). The structure elucidation of one of them, CE-108D (3a), confirmed the incorporation of an alternative extender unit for elongation step 13. Other compounds were also overproduced in the fermentation broth of rimJ disruptant. The new compounds are in vivo substrates for the previously described polyene carboxamide synthase PcsA. The rimJ disruptant strain, constitutively expressing the pcsA gene, allowed the overproduction of CE-108E (3b), the corresponding carboxamide derivative of CE-108D (3a), with improved pharmacological properties.

ELF3-PIF4 interaction regulates plant growth independently of the Evening Complex

The circadian clock plays a pivotal role in the control of Arabidopsis hypocotyl elongation by regulating rhythmic expression of the bHLH factors PHYTOCHROME INTERACTING FACTOR 4 and 5 (PIF4 and 5). Coincidence of increased PIF4/PIF5 transcript levels with the dark period allows nuclear accumulation of these factors, and in short days it phases maximal hypocotyl growth at dawn. During early night, PIF4 and PIF5 transcription is repressed by the Evening Complex (EC) proteins EARLY FLOWERING3 (ELF3), EARLY FLOWERING4 (ELF4), and LUX ARRHYTHMO (LUX). While ELF3 has an essential role in EC complex assembly, several lines of evidence indicate that this protein controls plant growth via other mechanisms that are presently unknown. Here, we show that the ELF3 and PIF4 proteins interact in an EC-independent manner, and that this interaction prevents PIF4 from activating its transcriptional targets. We also show that PIF4 overexpression leads to ELF3 protein destabilization, and that this effect is mediated indirectly by negative feedback regulation of photoactive PHYTOCHROME B (phyB). Physical interaction of the phyB photoreceptor with ELF3 has been reported, but its functional relevance remains poorly understood. Our findings establish that phyB is needed for ELF3 accumulation in the light, most likely by competing for CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)-mediated ubiquitination and the proteasomal degradation of ELF3. Our results explain the short hypocotyl phenotype of ELF3 overexpressors, despite their normal clock function, and provide a molecular framework for understanding how warm temperatures promote hypocotyl elongation and affect the endogenous clock.

Nicotiana benthamiana resistance to non-adapted Melon necrotic spot virus results from an incompatible interaction between virus RNA and translation initiation factor 4E

Nicotiana benthamiana has been described as non-host for Melon necrotic spot virus (MNSV). We investigated the basis of this resistance using the unique opportunity provided by strain MNSV-264, a recombinant virus that is able to overcome the resistance. Analysis of chimeric MNSV mutants showed that virulence in N. benthamiana is conferred by a 49 nucleotide section of the MNSV-264 3'-UTR, which acts in this host as a cap-independent translational enhancer (3'-CITE). Although the 3'-CITE of non-adapted MNSV-Mα5 is active in susceptible melon, it does not promote efficient translation in N. benthamiana, thus preventing expression of proteins required for virus replication. However, MNSV-Mα5 gains the ability to multiply in N. benthamiana cells if eIF4E from a susceptible melon variety (Cm-eIF4E-S) is supplied in trans. These data show that N. benthamiana resistance to MNSV-Mα5 results from incompatibility between the MNSV-Mα5 3'-CITE and N. benthamiana eIF4E in initiating efficient translation of the viral genome. Therefore, non-host resistance conferred by the inability of a host susceptibility factor to support viral multiplication may be a possible mechanism for this type of resistance to viruses.

ccz-1 mediates the digestion of apoptotic corpses in C. elegans

During development, the processes of cell division, differentiation and apoptosis must be precisely coordinated in order to maintain tissue homeostasis. The nematode C. elegans is a powerful model system in which to study cell death and its control. C. elegans apoptotic cells condense and form refractile corpses under differential interference contrast (DIC) microscopy. Activation of the GTPase CED-10 (Rac) in a neighbouring cell mediates the recognition and engulfment of the cell corpse. After inclusion of the engulfed corpse in a phagosome, different proteins are sequentially recruited onto this organelle to promote its acidification and fusion with lysosomes, leading to the enzymatic degradation of the cell corpse. We show that CCZ-1, a protein conserved from yeasts to humans, mediates the digestion of these apoptotic corpses. CCZ-1 seems to act in lysosome biogenesis and phagosome maturation by recruiting the GTPase RAB-7 over the phagosome.

The pcsA gene from Streptomyces diastaticus var. 108 encodes a polyene carboxamide synthase with broad substrate specificity for polyene amides biosynthesis

Two structurally related polyene macrolides are produced by Streptomyces diastaticus var. 108: rimocidin (3a) and CE-108 (2a). Both bioactive metabolites are biosynthesized from the same pathway through type I polyketide synthases by choosing a starter unit either acetate or butyrate, resulting in 2a or 3a formation, respectively. Two additional polyene amides, CE-108B (2b) and rimocidin B (3b), are also produced "in vivo" when this strain was genetically modified by transformation with engineered SCP2*-derived vectors carrying the ermE gene. The two polyene amides, 2b and 3b, showed improved pharmacological properties, and are generated by a tailoring activity involved in the conversion of the exocyclic carboxylic group of 2a and 3a into their amide derivatives. The improvement on some biological properties of the resulting polyenes, compared with that of the parental compounds, encourages our interest for isolating the tailoring gene responsible for the polyene carboxamide biosynthesis, aimed to use it as tool for generating new bioactive compounds. In this work, we describe the isolation from S. diastaticus var. 108 the corresponding gene, pcsA, encoding a polyene carboxamide synthase, belonging to the Class II glutamine amidotransferases and responsible for "in vivo" and "in vitro" formation of CE-108B (2b) and rimocidin B (3b). The fermentation broth from S. diastaticus var. 108 engineered with the appropriate pcsA gene construction, showed the polyene amides to be the major bioactive compounds.

Mechanism of plant eIF4E-mediated resistance against a Carmovirus (Tombusviridae): cap-independent translation of a viral RNA controlled in cis by an (a)virulence determinant

Translation initiation factors are universal determinants of plant susceptibility to RNA viruses, but the underlying mechanisms are poorly understood. Here, we show that a sequence in the 3' untranslated region (3'-UTR) of a viral genome that is responsible for overcoming plant eIF4E-mediated resistance (virulence determinant) functions as a 3' cap-independent translational enhancer (3'-CITE). The virus/plant pair studied here is Melon necrotic spot virus (MNSV) and melon, for which a recessive resistance controlled by melon eIF4E was previously described. Chimeric viruses between virulent and avirulent isolates enabled us to map the virulence and avirulence determinants to 49 and 26 nucleotides, respectively. The translational efficiency of a luc reporter gene flanked by 5'- and 3'-UTRs from virulent, avirulent and chimeric viruses was analysed in vitro, in wheatgerm extract, and in vivo, in melon protoplasts, showing that: (i) the virulence determinant mediates the efficient cap-independent translation in vitro and in vivo; (ii) the avirulence determinant was able to promote efficient cap-independent translation in vitro, but only when eIF4E from susceptible melon was added in trans, and, coherently, only in protoplasts of susceptible melon, but not in the protoplasts of resistant melon; (iii) these activities required the 5'-UTR of MNSV in cis. Thus, the virulence and avirulence determinants function as 3'-CITEs. The activity of these 3'-CITEs was host specific, suggesting that an inefficient interaction between the viral 3'-CITE of the avirulent isolate and eIF4E of resistant melon impedes the correct formation of the translation initiation complex at the viral RNA ends, thereby leading to resistance.

Nummular headache with trophic changes inside the painful area

Nummular headache (NH) is a primary disorder characterized by chronic pain that is exclusively felt in a small area of the head surface. We describe five patients with circumscribed head pain and sensory dysfunction consistent with NH, who in addition developed colocalized trophic changes. All of them had a round or oval patch of skin depression (1-2 cm in diameter) inside of the painful area (2-4.5 cm in diameter). Three of them also showed hair loss, reddish colour, and local increased temperature. Skin biopsies were performed in three patients, and were not specific for any particular dermatological disease. Local trophic changes may be a clinical feature of NH. Together with pain and sensory disturbances, they could represent a restricted form of complex regional pain syndrome. This should be taken as a possible evolution of the underlying morbid process of NH.

Epicrania fugax: an ultrabrief paroxysmal epicranial pain

Ten patients (one man and nine women, mean age 48.8 +/- 20.1) presented with a stereotypical and undescribed type of head pain. They complained of strictly unilateral, shooting pain paroxysms starting in a focal area of the posterior parietal or temporal region and rapidly spreading forward to the ipsilateral eye (n = 7) or nose (n = 3) along a lineal or zigzag trajectory, the complete sequence lasting 1-10 s. Two patients had ipsilateral lacrimation, and one had rhinorrhoea at the end of the attacks. The attacks could be either spontaneous or triggered by touch on the stemming area (n = 2), which could otherwise remain tender or slightly painful between the paroxysms (n = 5). The frequency ranged from two attacks per month to countless attacks per day, and the temporal pattern was either remitting (n = 5) or chronic (n = 5). This clinical picture might be a variant of an established headache or represent a novel syndrome.

EcoTILLING for the identification of allelic variants of melon eIF4E, a factor that controls virus susceptibility

BACKGROUND

Translation initiation factors of the 4E and 4G protein families mediate resistance to several RNA plant viruses in the natural diversity of crops. Particularly, a single point mutation in melon eukaryotic translation initiation factor 4E (eIF4E) controls resistance to Melon necrotic spot virus (MNSV) in melon. Identification of allelic variants within natural populations by EcoTILLING has become a rapid genotype discovery method.

RESULTS

A collection of Cucumis spp. was characterised for susceptibility to MNSV and Cucumber vein yellowing virus (CVYV) and used for the implementation of EcoTILLING to identify new allelic variants of eIF4E. A high conservation of eIF4E exonic regions was found, with six polymorphic sites identified out of EcoTILLING 113 accessions. Sequencing of regions surrounding polymorphisms revealed that all of them corresponded to silent nucleotide changes and just one to a non-silent change correlating with MNSV resistance. Except for the MNSV case, no correlation was found between variation of eIF4E and virus resistance, suggesting the implication of different and/or additional genes in previously identified resistance phenotypes. We have also characterized a new allele of eIF4E from Cucumis zeyheri, a wild relative of melon. Functional analyses suggested that this new eIF4E allele might be responsible for resistance to MNSV.

CONCLUSION

This study shows the applicability of EcoTILLING in Cucumis spp., but given the conservation of eIF4E, new candidate genes should probably be considered to identify new sources of resistance to plant viruses. Part of the methodology described here could alternatively be used in TILLING experiments that serve to generate new eIF4E alleles.

An eIF4E allele confers resistance to an uncapped and non-polyadenylated RNA virus in melon

The characterization of natural recessive resistance genes and virus-resistant mutants of Arabidopsis have implicated translation initiation factors of the 4E family [eIF4E and eIF(iso)4E] as susceptibility factors required for virus multiplication and resistance expression. To date, viruses controlled by these genes mainly belong to the family Potyviridae. Melon necrotic spot virus (MNSV) belongs to the family Tombusviridae (genus Carmovirus) and is an uncapped and non-polyadenylated RNA virus. In melon, nsv-mediated resistance is a natural source of recessive resistance against all strains of MNSV except MNSV-264. Analyses of chimeras between non-resistance-breaking and resistance-breaking strains have shown that the avirulence determinant maps to the 3'-untranslated region (3'-UTR) of the viral genome. Using a combination of positional cloning and microsynteny analysis between Arabidopsis thaliana and melon, we genetically and physically delimited the nsv locus to a single bacterial artificial chromosome clone and identified the melon eukaryotic translation initiation factor 4E (Cm-eIF4E) as a candidate gene. Complementation analysis using a biolistic transient expression assay, confirmed Cm-eIF4E as the product of nsv. A single amino acid change at position 228 of the protein led to the resistance to MNSV. Protein expression and cap-binding analysis showed that Cm-eIF4E encoded by a resistant plant was not affected in it's cap-binding activity. The Agrobacterium-mediated transient expression of the susceptibility allele of Cm-eIF4E in Nicotiana benthamiana enhanced MNSV-264 accumulation. Based on these results, a model to explain melon resistance to MNSV is proposed. These data, and data from other authors, suggest that translation initiation factors of the eIF4E family are universal determinants of plant susceptibility to RNA viruses.

A physical map covering the nsv locus that confers resistance to Melon necrotic spot virus in melon (Cucumis melo L.)

Melon necrotic spot virus (MNSV) is a member of the genus Carmovirus, which produces severe yield losses in melon and cucumber crops. The nsv gene is the only known natural source of resistance against MNSV in melon, and confers protection against all widespread strains of this virus. nsv has been previously mapped in melon linkage group 11, in a region spanning 5.9 cM, saturated with RAPD and AFLP markers. To identify the nsv gene by positional cloning, we started construction of a high-resolution map for this locus. On the basis of the two mapping populations, F(2) and BC1, which share the same resistant parent PI 161375 (nsv/nsv), and using more than 3,000 offspring, a high-resolution genetic map has been constructed in the region around the nsv locus, spanning 3.2 cM between CAPS markers M 29 and M 132. The availability of two melon BAC libraries allowed for screening and the identification of new markers closer to the resistance gene, by means of BAC-end sequencing and mapping. We constructed a BAC contig in this region and identified the marker 52 K 20 sp 6, which co-segregates with nsv in 408 F(2) and 2.727 BC1 individuals in both mapping populations. We also identified a single 100 kb BAC that physically contains the resistance gene and covers a genetic distance of 0.73 cM between both BAC ends. These are the basis for the isolation of the nsv recessive-resistance gene.

[Pulsed radiofrequency treatment in idiopathic and secondary glossopharyngeal neuralgia: preliminary results in 2 cases]

OBJECTIVES

To describe the use of pulsed radiofrequency (PRF) to treat 2 cases of glossopharyngeal neuralgia, 1 idiopathic and 1 secondary.

PATIENTS

The first case involved a man diagnosed with Hodgkin's lymphoma involving the tonsils and manifesting as glossopharyngeal neuralgia that was refractory to all treatment approaches tried, including opioids and neuromodulation. The second case involved a patient diagnosed with essential glossopharyngeal neuralgia that was also resistant to drug treatment. The PRF procedure was performed in the operating room on an outpatient basis, under fluoroscopic guidance and with conventional monitoring. No perioperative events were reported.

RESULTS

The treatment was effective for both patients, leading to decreases in visual analog scale pain reports between 5 and 7 points that were maintained over 6 months, although improvement for the patient with essential neuralgia was less intense and of shorter duration. Overall self-reported improvement assessed subjectively 6 months after PRF was 75% for the patient with Hodgkin's lymphoma and 50% for the patient with essential neuralgia, for whom a second PRF procedure was scheduled. Neither patient suffered complications or side effects that were potentially attributable to the procedure.

CONCLUSIONS

PRF seems to be a safe, effective approach to treating neuralgia of the glossopharyngeal nerve, whether the condition is essential or secondary to another process. It is possible that if the condition is secondary, the clinical response may be greater in intensity and last longer.

Molecular characterization of a Melon necrotic spot virus strain that overcomes the resistance in melon and nonhost plants

Resistance of melon (Cucumis melo L.) to Melon necrotic spot virus (MNSV) is inherited as a single recessive gene, denoted nsv. No MNSV isolates described to date (e.g., MNSV-Malpha5), except for the MNSV-264 strain described here, are able to overcome the resistance conferred by nsv. Analysis of protoplasts of susceptible (Nsv/-) and resistant (nsv/nsv) melon cultivars inoculated with MNSV-264 or MNSV-Malpha5 indicated that the resistance trait conferred by this gene is expressed at the single-cell level. The nucleotide sequence of the MNSV-264 genome has a high nucleotide identity with the sequences of other MNSV isolates, with the exception of its genomic 3'-untranslated region (3'-UTR), where less than 50% of the nucleotides are shared between MNSV-264 and the other two MNSV isolates completely sequenced to date. Uncapped RNAs transcribed from a full-length MNSV-264 cDNA clone were infectious and caused symptoms indistinguishable from those caused by the parental viral RNA. This cDNA clone allowed generation of chimeric mutants between MNSV-264 and MNSV-Malpha5 through the exchange of the last 74 nucleotides of their coat protein (CP) open reading frames and the complete 3'-UTRs. Analysis of protoplasts of susceptible and resistant melon cultivars inoculated with chimeric mutants clearly showed that the MNSV avirulence determinant resides in the exchanged region. The carboxy-termini of the CP of both isolates are identical; therefore, the avirulence determinant likely consists of the RNA sequence itself. We also demonstrated that this genomic region contains the determinant for the unique ability of the isolate MNSV-264 to infect noncucurbit hosts (Nicotiana benthamiana and Gomphrena globosa).

Advances in understanding recessive resistance to plant viruses

SUMMARY Recent work carried out to characterize recessive mutations which render experimental hosts non-permissive to viral infection (loss-of-susceptibility mutants) seems to be converging with new data on natural recessive resistance in crop species, and also with functional analyses of virus avirulence determinants. Perhaps the most well known examples are the studies that identified the eukaryotic translation initiation factors 4E(iso) (eIF(iso)4E) and 4E(eIF4E) as the host factors required for potyvirus multiplication within experimental and natural hosts, respectively, and the potyviral genome-linked protein (VPg) as the viral factor that directly interacts with eIF4E to promote potyvirus multiplication. The purpose of this paper is to review the available information on the characterization of loss-of-susceptibility mutants in experimental hosts, natural recessive resistances and virus avirulence factors, and also to comment on possible implications for the design of new sources of sustainable virus resistance.

Theoretic rates of potential tissue donation in a university hospital

BACKGROUND

Catalonia and Spain have the highest rates of organ donation in the world. The National Transplant Organization studied the rates of potential and actual donors through the Quality Guarantee Program, but this research did not estimate potential tissue donation (PTD). The aim of this study was to define the theoretical rates of PTD at our university hospital in order to assess the main factors that exerted the greatest influence on tissue donation (TD).

METHODS

We prospectively studied all deaths from May 1, of 2001 to May 31, of 2002 using a specific protocol. The selection of cornea, vessels, skin, and bone had been established by the recommendations of the Spanish Association of Tissue Banks (AEBT). We considered each deceased person as a PTD when there was no medical contraindication (MC), and obtained blood samples for serologic determinations.

RESULTS

Among the 1960 deaths, 1444 (73.6%) displayed MC for TD. Only 516 (26.3%) patients were evaluated as PTD cases. Two hundred twenty-two cases (65%) were rejected due to lack of blood samples for serologic determination. The remaining 294 PTD cases were considered: family refusal of TD in 120 (40%) and consent in 174 (60%). All were corneal donors; 46 (26%) had been multitissue donors (20 vessels, 35 skin, and 30 bones) including 26 (56.5%) who were also organ donors.

CONCLUSIONS

PTD cases at a university hospital represented about 25% of deaths but only 30% of PTDs actually became donors.

Spanish Melon necrotic spot virus Isolate Overcomes the Resistance Conferred by the Recessive nsv Gene of Melon

Melon necrotic spot virus (MNSV, genus Carmovirus, family Tombusviridae) is a worldwide natural pathogen that can cause significant economic losses in cucurbit crops (2). Use of commercial cultivars that carry the recessive nsv gene, the only resistance to MNSV described until now (1), is an effective means of controlling MNSV on melon crops. We report here the appearance of MNSV isolates able to overcome nsv resistance. Typical MNSV symptoms were observed in plants with an nsv/nsv genotype during a survey of melon in Almería (southeastern Spain) in 1999. The presence of MNSV in symptomatic plants was confirmed by standard double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using commercial antisera (Loewe Biochemica GmbH, Sauerlach, Germany). MNSV was isolated from these samples by three serial single-lesion inoculation passages in melon (cv. Bola de Oro). The isolate obtained (MNSV-264) was characterized by sequencing a fragment of its RNA genome corresponding to most of the capsid protein (CP) gene. Briefly, total RNA extracts (TRI reagent, Sigma Chemical, St. Louis, MO) of MNSV-264-infected plants were used in a reverse transcription polymerase chain reaction (RT-PCR) in which the oligonucleotide for the reverse transcription was 5'-TTAGGCGAGGTAAGCAGTTTC-3' (MA34), and the oligonucleotides for the PCR were MA34 and 5'-ATGGCGATGGTTAAACGC-3' (MA32). MA32 and MA34 were designed based on an alignment of nucleotide sequences of CP genes of diverse MNSV isolates. A DNA product of approximately 1.1 kbp was obtained, purified, and sequenced (GenBank Accession No. AF488692). Sequence comparisons (GCG Software Package, Madison, WI) of MNSV-264 and MNSV-Dutch (2) showed a 93% nucleotide sequence identity and a 96% similarity of the deduced amino acid sequence. Therefore, both isolates appear to be closely related. MNSV-264 was inoculated on melon accessions known to be susceptible (cvs. Panal and Bola de Oro) or resistant (cvs. Primal F1, Planters Jumbo, and PI161375) to common MNSV strains. Inoculations with MNSV-Dutch were used as a control for this experiment. The results showed that MNSV-264 was able to infect plants of all genotypes, whereas MNSV-Dutch infected only plants of the susceptible genotypes. Therefore, MNSV-264 is an isolate able to overcome the resistance conferred by nsv. The genetic determinant of the MNSV-264 virulence on resistant genotypes is currently under investigation. From 55 MNSV isolates obtained from fields in southeastern Spain during the last 3 years, only one could overcome nsv, like MNSV-264. Therefore, resistance-breaking isolates are not frequent in the MNSV populations in Spain. It is plausible that the situation may change as a consequence of the widespread use of commercial melon cultivars with the nsv genotype. A search for new sources of genetic resistance to MNSV isolates like MNSV-264 is in progress in our laboratory. References: (1) D. L. Coudriet et al. J. Am. Soc. Hortic. Sci. 106:789, 1981. (2) C. J. Riviere et al. J. Gen. Virol. 70:3033, 1989.

[Inverted duplication of the short arm of chromosome 8]

We report two cases of agenesis of corpus callosum in which high resolution G-band cytogenetic study revealed inverted duplication of the short arm of chromosome 8. The application of hybridization techniques with fluorescence in situ hybridization (FISH) confirmed chromosomal alteration in both cases. The definitive karyotype was 46, XY or XX inv dup del (8) (qter-p23.1::p23.1-p11.2).ish (WCP 8 ) (tel 8p-).

MalR-mediated regulation of the Streptococcus pneumoniae malMP operon at promoter PM. Influence of a proximal divergent promoter region and competition between MalR and RNA polymerase proteins

The Streptococcus pneumoniae mal regulon contains two operons, malXCD and malMP involved in the uptake and utilization of maltosaccharides. Both operons are transcribed from two divergent promoters, P(X) and P(M), and are negatively regulated by the MalR transcriptional repressor. Purified MalR protein binds to two DNA regions that encompasses both promoters, thus occupying its two operators, O(M) and O(X). However, the levels of occupation and repression were different, being higher when MalR was bound to O(M) than when it was anchored to O(X). Competition experiments between MalR and the Escherichia coli RNA polymerase on promoters P(M) and P(X) showed that the affinity of either protein for the promoter/operator DNA sequences was important to determine the frequency of transcription initiation. In addition to the control exerted by MalR, expression from promoter P(M) was affected by upstream sequences located within or close to P(X) promoter.

Construction of a tightly regulated plasmid vector for Streptococcus pneumoniae: controlled expression of the green fluorescent protein

We have constructed a regulated plasmid vector for Streptococcus pneumoniae, based on the streptococcal broad-host-range replicon pLS1. As a reporter gene, we subcloned the gfp gene from Aequorea victoria, encoding the green fluorescent protein. This gene was placed under the control of the inducible P(M) promoter of the S. pneumoniae malMP operon which, in turn, is regulated by the product of the pneumococcal malR gene. Binding of MalR protein to the P(M) promoter is inactivated by growing the cells in maltose-containing media. Highly regulated gene expression was achieved by cloning in the same plasmid the P(M)-gfp cassette and the malR gene, thus providing the MalR regulator in cis. Pneumococcal cells harboring this vector gave a linear response of GFP synthesis in a maltose-dependent mode without detectable background levels in the absence of the inducer.

Expression of green fluorescent protein in Lactococcus lactis

The gfp gene from Aequorea victoria, encoding the green fluorescent protein (GFP) has been expressed in Lactococcus lactis subsp. lactis biovar cremoris MG1363, upon construction and introduction of plasmid pLS1GFP into this host. GFP was monitored in living cells during growth to evaluate its use in molecular and physiological studies. Quantification of the levels of GFP expressed by cultures was feasible by fluorescence spectroscopy. Phase-contrast and fluorescence microscopy allowed us to distinguish, in mixed cultures, lactococcal cells expressing GFP. Our results indicate that GFP can be used as a reporter in L. lactis.

[Brachmann-de-Lange syndrome in our population: clinical and epidemiological characteristics]

INTRODUCTION

We present the study of the clinical and epidemiological characteristics of Brachmann-de Lange syndrome in our population.

PATIENTS AND METHODS

In this study we present the analysis of 13 cases of Brachmann-de Lange syndrome identified among 24,696 infants with congenital defects registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and June 1996.

RESULTS

The minimum estimation of the prevalence in our population is 0.97 per 100,000 live births. We have epidemiologically confirmed the presence of intrauterine growth retardation and have observed that parental ages tend to be relatively young. We have observed a wide range of clinical expression of this syndrome. One hundred percent of our cases have limb reduction defects, followed in frequency by craniofacial alterations (84.62%), abnormal hair distribution (76.92%) and genital defects (69.23%). Upper limbs are predominantly affected and one case of diaphragmatic hernia is worth mentioning. We underline the importance of the differential diagnosis with Fryns'syndrome.

CONCLUSIONS

The cases studied correspond to the most severe form of the syndrome, reason for which the prevalence is a minimal estimate. However, the mild forms of the syndrome are more frequent and it is important to consider that the face, especially the form of the eyebrow, could be a good guide for the diagnosis of mild forms of the syndrome.

The maltose/maltodextrin regulon of Streptococcus pneumoniae. Differential promoter regulation by the transcriptional repressor MalR

The Streptococcus pneumoniae MalR protein regulates the transcription of two divergent operons, malXCD and malMP, involved in maltosaccharide uptake and utilization, respectively. MalR belongs to the LacI-GalR family of transcription repressors. The protein binds specifically to two operator sequences in the intergenic region between these operons. The affinity of MalR for the malMP binding sequence is higher than for the malXCD site. Results obtained in vivo using transcriptional fusions with reporter genes indicate low repression level of malXCD by MalR when compared with malMP. This behavior may be correlated with the existence of separate induction pathways for maltose, maltotriose, and maltotetraose. The similarities found at the operator sequences and binding domains for MalR and enterococcal repressor proteins suggest that the pneumococcal maltosaccharide regulation system is closely related to several Gram-negative metabolic pathways, but not to the structurally similar Escherichia coli maltose regulon.

MYB.Ph3 transcription factor from Petunia hybrida induces similar DNA-bending/distortions on its two types of binding site

MYB.Ph3 from Petunia is a member of the MYB transcription factor family that recognizes two types of binding site, resembling direct and inverted repeats of the motif GTTA, respectively, and flanked on their 5' side by an A-rich sequence. In this study, it is shown that MYB.Ph3 induces similar conformational changes in both of its DNA-binding sites. Circular permutation assays indicate that the center of the distortions induced by MYB.Ph3 maps near the center of either MYB.Ph3-binding site. The degree of the distortion induced by MYB.Ph3 appears to be greatly affected by regions of the protein other than the DNA-binding domain, and differs from the distortion caused by animal c-MYB. Phasing analysis reveals that part of the distortion induced by MYB.Ph3 is DNA bending, oriented towards the minor groove, as is the case of its animal counterpart, c-MYB. DNA-binding by both MYB.Ph3 and animal c-MYB is more efficient in the presence of Ba2+, a divalent cation known to promote/stabilize DNA bending, than in the presence of other cations which do not favor this distortion, such as Na+ and Mg2+. In addition, both MYB proteins show higher affinity to selectively nicked DNA, which has increased DNA flexibility, strongly suggesting that DNA binding by these MYB proteins and DNA structural properties are mutually influenced.

Dual DNA binding specificity of a petal epidermis-specific MYB transcription factor (MYB.Ph3) from Petunia hybrida

The MYB.Ph3 protein recognized two DNA sequences that resemble the two known types of MYB DNA binding site: consensus I (MBSI), aaaAaaC(G/C)-GTTA, and consensus II (MBSII), aaaAGTTAGTTA. Optimal MBSI was recognized by animal c-MYB and not by Am305 from Antirrhinum, whereas MBSII showed the reverse behaviour. Different constraints on MYB.Ph3 binding to the two classes of sequences were demonstrated. DNA binding studies with mutated MBSI and MBSII and hydroxyl radical footprinting analysis, pointed to the N-terminal MYB repeat (R2) as the most involved in determining the dual DNA binding specificity of MYB.Ph3 and supported the idea that binding to MBSI and MBSII does not involve alternative orientations of the two repeats of MYB.Ph3. Minimal promoters containing either MBSI and MBSII were activated to the same extent by MYB.Ph3 in yeast, indicating that both types of binding site can be functionally equivalent. MYB.Ph3 binding sites are present in the promoter of flavonoid biosynthetic genes, such as the Petunia chsJ gene, which was transcriptionally activated by MYB.Ph3 in tobacco protoplasts. MYB.Ph3 was immunolocalized in the epidermal cell layer of petals, where flavonoid biosynthetic genes are actively expressed. This strongly suggests a role for MYB.Ph3 in the regulation of flavonoid biosynthesis.

[A controlled study of the effect of oral contraceptives on blood pressure]

The possible hypertensive effect of oral contraceptives is a controversial issue. We studied 371 women, admitted to the family planning program of a state funded outpatient clinic, that were followed during 12 months. These women were divided in four groups: Group 1 was constituted by 98 women that used intrauterine devices. Group 2 by 98 women taking 30 micrograms of estrogen and 300 micrograms of progestogen. Group 3 by 83 women taking 35 micrograms of estrogen and 500 micrograms of progestogen and Group 4 by 92 puerperal women taking 30 micrograms of levonorgestrel, that after six months started to use an intrauterine device (n = 35) or the contraceptives of group 2 (n = 38) or group 3 (n = 19). Age, initial blood pressure and weight were similar in the four groups. There was no significant change in blood pressure after 6 or 12 months of follow up in any group. It is concluded that contraceptives containing estrogen concentrations up to 35 micrograms and progestogen concentrations between 300 and 500 micrograms do not induced changes in blood pressure.

On-line fully automated solid-phase extraction-liquid chromatography analysis of 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethyl-1-oxonaphthale ne-6- carbonitrile (UR-8225), a new potassium channel opener, in plasma samples

A fully automated reversed-phase HPLC method for pharmacokinetic studies was developed for the determination in plasma samples of 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethyl-1-oxonaphtha lene-6- carbonitrile (compound I), a new potassium channel opener. On-line solid-phase extraction was performed with disposable C18 cartridges. After clean up, the samples were eluted and transferred onto an RP-18 analytical column, where separation was performed with a mobile phase of acetonitrile-10 mM di-n-butylamine phosphate (28:72, v/v). Ultraviolet absorbance detection was used at 236 nm. The detector response was linear in the range 25-2500 ng/ml, and the lowest limit of quantitation was determined at 2.5 ng/ml. The inter-day variability was < 4% for samples at 1000 ng/ml and < 15% for samples at 10 ng/ml. This method was used for the pharmacokinetic study of compound I in rats at three different dosage levels.

Short rib-polydactyly syndrome and pericentric inversion of chromosome 4

We report on a newborn infant with clinical and radiological manifestations of some type of short rib-polydactyly syndrome who died soon after birth. Chromosomal studies on peripheral blood lymphocytes and chondrocytes demonstrated an apparently balanced pericentric inversion of chromosome 4 (present in the mother also). This association may have occurred by chance but, if not, the chromosomal breakpoints could interrupt the gene responsible for short rib-polydactyly syndromes, or else be related to the mechanism of short rib-polydactyly syndromes.

[Hypertension in rural communities. Study in the VIII Region, Chile]

The aim of this work was to study the prevalence of hypertension in rural populations of the VIII region of Chile. Six thousand twenty four non institutionalized subjects. 14 years old or older, coming from eight randomly chosen rural communities were studied. Blood pressure was measured by trained personnel in two occasions within 30 minutes; in those classified as hypertensive, a third measurement was performed within 24 hours, eliminating alcohol intake and medications. Results show prevalence rates in the first, second and third measurement of 38.5, 30.8 and 22.8% respectively. The elimination of alcohol intake and medications decreased the prevalence in 3.9%. All the chosen communities has similar rates (19.8 to 21.2%) except Arauco, that had a significantly higher frequency of 31.9%. Zones of extreme ruralness had higher rates than small towns (23.8 vs 21.7%). There was a secular increase in the prevalence of hypertension from 4.9 in the 15 to 24 years old group to 57.8% among people 75 years old or older. Forty three percent of hypertensives were aware of such condition, 26.1% were receiving treatment and in 8.2% it was successful; all these figures were slightly better among women.

Petunia hybrida genes related to the maize regulatory C1 gene and to animal myb proto-oncogenes

The maize C1 gene is a regulatory gene of the anthocyanin pathway. It is a part of a multigene family whose predicted protein products contain a region with homology to the DNA-binding domain of myb proto-oncogene products. Using as a probe an oligonucleotide mixture encoding a highly conserved region in plant MYB proteins, cDNAs encoding three related polypeptides expressed in the flower of Petunia hybrida have been isolated. Predicted proteins are 280-517 amino acids long and show sequence similarities among themselves as well as with other MYB proteins (45-80% amino acid identity) in the MYB DNA-binding domain. Outside this domain no significant sequence similarity was found. However, in all cases regions with structural characteristics of activator domains were found. Analysis with Southern blots allowed an estimation of at least 20-30 myb genes in P. hybrida. Expression patterns were specific for each gene as shown by Northern blotting analysis. Subcellular location studies of the largest MYB product, by both immunoblotting of the protein in subcellular fractions and by 'in situ' immunolocation experiments, showed that it is a nuclear protein. The role of MYB proteins as transcriptional activators regulating the synthesis of different anthocyanin(flavonoid)-related compounds is discussed.

[The use of endocavitary fulguration in the treatment of common auricular flutter]

Between April 1990 and July 1991, 10 patients, were fulgurated after right atrial endocardial mapping with the purpose of destroying or modifying the site of origin of atrial flutter. Mean age, 47 years old (23-61), 9 males. All patients suffered "common" atrial flutter episodes with very rapid ventricular response (greater than or equal to 150 beats per minute) refractory to pharmacological therapy. All patients had pathologic potentials with prolonged duration between 90 and 160 ms (m = 109) which preceded other reference electrodes in the high right atrium and His position. Electrical stimulation from that zone provoked the capture entrainment and termination of the flutter; the same configuration of the arrhythmia was obtained with electrical stimulation from the suspected zone. With the catheter in that situation one or two direct current cathodic, unipolar shocks were given with energy of 60-150 Joules (m = 117). In the follow up (16-73 weeks), 8 patients are free of symptoms without drugs, one suffered a new episode after 7 weeks, His fulguration was performed and a permanent pacemaker implanted. The other patient has failed two session and is still on treatment.