Kinematics of male Eupalaestrus weijenberghi (Araneae, Theraphosidae) locomotion on different substrates and inclines

Background. The mechanics and energetics of spider locomotion have not been deeply investigated, despite their importance in the life of a spider. For example, the reproductive success of males of several species is dependent upon their ability to move from one area to another. The aim of this work was to describe gait patterns and analyze the gait parameters of Eupalaestrus weijenberghi (Araneae, Theraphosidae) in order to investigate the mechanics of their locomotion and the mechanisms by which they conserve energy while traversing different inclinations and surfaces. Methods. Tarantulas were collected and marked for kinematic analysis. Free displacements, both level and on an incline, were recorded using glass and Teflon as experimental surfaces. Body segments of the experimental animals were measured, weighed, and their center of mass was experimentally determined. Through reconstruction of the trajectories of the body segments, we were able to estimate their internal and external mechanical work and analyze their gait patterns. Results. Spiders mainly employed a walk-trot gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected regarding the different planes or surfaces with respect to duty factor, time lags, stride frequency, and stride length. However, postural changes were observed on slippery surfaces. The mechanical work required for traversing a level plane was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all of the total mechanical work. The internal work was extremely low and did not rise as the gradient increased. Discussion. Our results support the idea of considering the eight limbs functionally divided into two quadrupeds in series. The anterior was composed of the first two pairs of limbs, which have an explorative and steering purpose and the posterior was more involved in supporting the weight of the body. The mechanical work to move one unit of mass a unit distance is almost constant among the different species tested. However, spiders showed lower values than expected. Minimizing the mechanical work could help to limit metabolic energy expenditure that, in small animals, is relatively very high. However, energy recovery due to inverted pendulum mechanics only accounts for only a small fraction of the energy saved. Adhesive setae present in the tarsal, scopulae, and claw tufts could contribute in different ways during different moments of the step cycle, compensating for part of the energetic cost on gradients which could also help to maintain constant gait parameters

Lower cost of transport coincides with self-selected walking speed in pregnant individuals

Pregnancy has important structural and physiological changes related to the growth of the baby [1]. These changes can alter metabolic and biomechanical parameters of pregnant individuals (PI) [2]. Changes in the body centre of mass (CM), body dimensions, and weight can influence postural aspects as well as gait [3]. Thus, changes may occur in different variables such as cost of transport (C J.kg-1.m-1) [4], ventilatory efficiency evaluated by the ventilatory equivalent for carbon dioxide (VE/VCO2), and walking speed. Aim: to compare C, VE/VCO2, self-selected walking speed (SSWS) on treadmill and on a track, at different walking speeds, of PI and a control group (CG). PI: n=24 (n=8 in 1st trimester (T1), 12-13 wks; n=8 in 2nd trim. (T2), 26-27 wks; n=8 in 3rd trim. (T3), 35-36 wks); CG: n=8 healthy non-PI. VO2 uptake was collected during trials of 5 min at 5 walking speeds, in randomized order (SSWS, ±40%, ±20% of SSWS) on the treadmill [5]. The SSWS was initially assessed on a track, and then tested on the treadmill. ANOVA for repeated measures was used to compare C and VE/VCO2 for walking speed and groups. One-way ANOVA was used to compare SSWS on the track and on the treadmill. Multiple comparisons were possibly made with Tukey’s post-hoc analysis (α=0.05). Values of C were higher in PI compared to CG for all T (p=0.005; differences between trimesters p=0.001). VE/VCO2 also showed higher values for PI (among T p<0.0001) compared to CG (p<0.0001). Differences in the SSWS (T1 0.83±0.14; T2 0.82±0.18; T3 0.85±0.18; CG 1.01±0.14 m.s-1) on the treadmill and on the track were found for all T (p<0.0001), and between PI and CG (p<0.0001). C always showed the characteristics of "U" shape described previously [4], with higher metabolic economy at SSWS. Interestingly, VE/VCO2 showed higher values in T2 compared to T1, T3 and CG. VE/VCO2 is known to be affected by increased chemoreceptor numbers, peripheral ergoreceptor response, dead space ventilation, and muscle mass involved in exercise [2]. The feeling of greater respiratory difficulty with the increase in walking speed and due to the smaller excursion of the diaphragm by the increased abdominal volume. Our results showed that the greatest respiratory comfort (lower VE/VCO2) occurred at the highest speed performed (above SSWS). The choice of SSWS seems to be related to a greater metabolic economy and not to respiratory comfort. After all physiological changes in T1 and T2 of pregnancy [1], T3 resulted to a certain adaptation. Lower metabolic economy is probably due to the physical alterations such as increase in body mass, displacement of the CM which could have altered the pendulum mechanism, generating displacement with less mechanical efficiency.Agencia Nacional de Investigación e Innovació

Morphometric study on tadpoles of Bombina variegata (Linnaeus, 1758) (Anura; Bombinatoridae)

The tadpoles of Yellow-bellied toad (Bombina variegata) can be easily recognized from other Italian anuran species, except those of B. pachypus (though the two congeneric species are allopatric). In this paper we report morphometric data on B. variegata tadpoles from a Lombard population living near a torrent at 450 m a.s.l. On a sample of 264 tadpoles (stages 19-44, according to Gosner, 1960) we measured the following five variables: snout-vent length, tail length, maximum tail height, total length and weight. We found a slight allometric relationship between snout-vent length and tail length, while, as expectes,.the weight is nearly proportional to the cube of linear measures. According to literature data, our results point to highly constant proportions during the development phases up to prometamorphic stages. The ratio between snout-vent length and tail length was about 0.75 during the whole growing phase, while from stage 42 the proportion increases as the resorption of the tail starts

Cambios posturales durante el embarazo comparación entre los trimestres

El embarazo genera diferentes cambios en el cuerpo, sean ellos fisiológicos, metabólicos y emocionales. Los cambios corporales, además de generar alteraciones en el funcionamiento de los sistemas, también generan alteraciones cuanto a movilidad, movimientos corporales y postura. Los efectos ocurren desde su modo de progresión en el espacio, bien como en las actividades diarias. Es probable que las mujeres embarazadas muestren comportamientos sedentarios y sean físicamente inactivas, debido a su necesidad de ajustarse a considerables cambios psicológicos y fisiológicos durante el embarazo (Foeczek et al., 2018). De acuerdo con “Orígenes del desarrollo de la salud y la enfermedad (Developmental Origin oh Health and Diseases (DOHaD)) los cuidados para evitar adulos con enfermedades crónicas comienzan durante el embarazo. La gestación es una de las únicas etapas en la cual es posible direccionar intervenciones para evitar enfermedades crónicas como obesidad, diabetes, hipertensión arterial, entre otras cardiopatías. La obesidad gestacional además de resultar en consecuencias negativas a la madre, aumenta las posibilidades de obesidad infantil y en la adolescencia, como enfermedades crónicas descriptas anteriormente (Charles, Delpierre, Bréant, 2016; Wojtyla, 2011; Hales et al., 1991; Barker & Osmond, 1986). Conocer los cambios y buscar estrategias de intervención es el mejor camino. El objetivo de este trabajo fue evaluar los cambios posturales durante cada trimestre de embarazo y compararlos a un grupo control (no embarazadas), para observar si existen cambios significativos a través del método flexicurve. Para ello fue utilizada la siguiente muestra: 14 embarazadas cursando el 1° trimestre (Tr) (edad: 30±4,5 años; masa: 62,8±18,6 kg; altura: 162,8±5,3 cm; índice de masa corporal (IMC) 23,5±3,2 kg.m-2). 17 en el 2ºTr (28,6±5,3 años; 67,2±9,7 kg, 162,5±4,4 cm; 25,7±2,9 kg.m-2). Y 19 en el 3ºTr (29,7±5,6 años; 69,8±8,8 kg; 163,2±7,1 cm; 26±3,3 kg.m-2), y un grupo control de mujeres no embarazadas (26,6±4,7 años; 63,1±9,8 kg; 161,2±5,9 cm; 24,2±3,1 kg.m-2). Todas las participantes contaban con autorización médica y firmaron el consentimiento informado antes de las evaluaciones. Para las evaluaciones posturales se utilizó una regla flexible “Flexicurve”, este es un método que se encuentra verificado en otros estudios, pero no fue utilizado para evaluar este tipo de poblaciones. Para su uso, la regla fue colocada en la espalda de cada participante imitando su curvatura de la columna, primero se evaluaron los ángulos toráxico-lumbar y luego cervicales. Para ello las participantes debían estar de pie mirando hacia una pared, para la primer evaluación los brazos debían estar apoyados en la pared a 90°, y se marcaban con un lápiz apto las apófisis espinosas de las vertebras: C7, T1, T12, L1, L5, S1. Para la evaluación cervical, la participante sentada realizaba unos movimientos de flexo-extensión de cuello y luego se paraba en su postura normal con los brazos a los lados, se marcaban las apófisis: C0, C2, C2, C7, T1, T2. En ambos casos se colocó la regla en la espalda y se copiaron estas marcas en ella, luego la regla es colocada sobre una hoja milimetrada, se copia esta curva y los puntos. Esto es cargado a un software “BiomecFlex 2.0” a través de un archivo jpg, y con la información de la persona (estatura, masa, e IMC) la aplicación nos brinda la medida de cada ángulo de dos formas: ángulo flex, que es el propio medido por la regla, y ángulo cob, que sería la estimación a una medición con rayos X. Se repitió el procedimiento en cada participante (embarazadas y controles) y se compararon los datos obtenidos. Para comparar las variables entre los trimestres se realizó un ANOVA de un factor y para la comparación flex-cobb intra-grupos Test-T, para verificar donde se encontraba la diferencia se realizó un Post Hoc de Bonferroni. Para establecer diferencia significativa se utilizó un p<0,05. Resultados parciales: En primer lugar no fueron encontradas diferencias significativas al comparar los ángulos flex y cobb en cada trimestre, esto indica la fiabilidad de la medición manual y la estimación de los rayos X. En la comparación entre grupos, en la columna cervical no se encontraron diferencias significativas entre el grupo de embarazadas, ni tampoco en comparación al grupo control. Para la columna toráxica, no se encontraron diferencias significativas entre trimestres, pero si en la comparación al grupo control: (p=0,032), al comparar cada grupo al grupo control la diferencia fue encontrada entre el 3erTR y el control (p= 0,0064). En la columna lumbar no se encontraron diferencias entre los trimestres, pero si en la comparación al grupo control (p= 0,0298), la comparación entre cada grupo al control demostró que las diferencias se encontraban entre el 2doTR y el control (0,016), y el 3eTR y el control (0,0039), pero no entre el 1erTr y Control (0,225). Como consideraciones finales, se puede considerar que las adaptaciones biomecánicas que ocurren en el cuerpo de la embarazada durante el progreso del embarazo debido al aumento (principalmente) de la zona abdominal, como consecuencia generan algunas compensaciones a nivel de su postura estática para lograr mantenerse de pie y realizar sus tareas diarias. Este aumento abdominal generó que las alteraciones del centro de gravedad (CG) hayan sido discutidas en cuanto a su posición, determinando que su desplazamiento se da principalmente antero-superior a medida que el feto crece hasta su 40% del peso final esperado (Branco, M. et al, 2016). La mujer embarazada para compensar este desplazamiento comienza a aumentar su lordosis lumbar, y compensa la postura modificando su cifósis toráxica. Estas alteraciones pueden repercutir en tareas cotidianas de la mujer embarazada y en acciones tan sencillos como la marcha, estudios demuestran que la mayoría de las personas muestran una activación de los músculos erectores de la columna vertebral durante la marcha normal(Carlsoo S, 1961; Klausen K 1968), hecho que parece estar relacionado con la ubicación anterior del CG respecto a la columna lumbar(Klausen, K, 1968; Kippers V, Parker AW, 1985). Así, de la misma manera, en las mujeres embarazadas los músculos posteriores pueden estar actuando como estabilizadores activos, tanto de la columna lumbar como de la pelvis, frente al aumento de la masa de la parte anterior del tronco y el correspondiente aumento del momento de flexión(Biviá-Roig et al, 2018) muestran que las respuestas musculares (mayor actividad eléctrica del gastrocnemios medial y lateral y de los erectores de la columna), se ven alteradas por el embarazo. Otro resultado importante es que la mayor activación eléctrica de los músculos es mantenida hasta dos meses después del parto. Se cree que ese aumento está detrás de la alta incidencia de dolor lumbar en las mujeres embarazadas y, de hecho, los regímenes de tratamiento del dolor de espalda que se administran a las mujeres embarazadas y en el posparto incluyen ejercicios para la reducción de las curvaturas lumbares mediante el ejercicio(Franklin ME, Conner-Kerr T, 1998), quizás el énfasis debería realizarse en ejercicios que fortalezcan los músculos estabilizadores de la columna y de este modo acompañar el aumento natural observado de las curvaturas para que los mismos no generen molestias o dolores durante el día diario, de este modo poder brindarles una gestación más confortable. Como comentarios finales, se debería considerar la flexicurve como una herramienta opcional al momento de evaluar la postura durante el embarazo, ya que es un método fácil, accesible y principalmente no es invasivo, y se podrán obtener resultados validados sin tener que someter a las mujeres embarazadas a pruebas riesgosas o de alto costo.Agencia Nacional de Investigación e Innovació

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Caratteristiche microstrutturali dell'EEG in sonno in bambini e adolescenti con ADHD.

Introduzione Il disturbo da deficit di attenzione e iperattività (ADHD) è un disturbo del neurosviluppo definito da un pattern persistente di disattenzione e / o iperattività-impulsività che interferisce con il funzionamento o lo sviluppo dell’individuo ed è spesso associato con compromissione delle relazioni interpersonali, delle interazioni sociali e del funzionamento scolastico. La prevalenza mondiale dell’ADHD nei bambini e negli adolescenti è di circa il 5.3% ed esso presenta un tasso di ereditabilità variabile tra il 70% e l’80%. Le comorbidità psichiatriche sono molto frequenti nell’ADHD, in particolare per quanto riguarda il disturbo oppositivo-provocatorio, il disturbo della condotta, i disturbi dell’umore e d’ansia e il disturbo d’abuso di sostanze, così come le comorbidità con altri disturbi del neurosviluppo, come i disturbi specifici dell’apprendimento, il disordine dello sviluppo della coordinazione, il disturbo dello spettro autistico, il disturbo del linguaggio, il disturbo da tic e la disabilità intellettiva. I problemi del sonno sono molto diffusi nei bambini e negli adolescenti con ADHD con tassi di prevalenza che arrivano, secondo i report dei genitori, fino al 70% e sono associati a un peggiore funzionamento globale, a una peggiore qualità della vita, a minori risultati scolastici, a una peggiore memoria di lavoro, e a sintomi depressivi e/o oppositivo-provocatori. Le principali aree cerebrali e i principali circuiti neurali e neurotrasmettitoriali implicati nella patogenesi dell’ADHD sono coinvolti anche nella regolazione del sonno ed è interessante osservare come molti dei deficit neuropsicologici propri dell’ADHD (funzioni esecutive, regolazione emotiva, apprendimento, memoria di lavoro, regolazione degli impulsi), così come la presenza di comportamenti oppositori e provocatori siano condivisi dai bambini con sviluppo tipico sottoposti a deprivazione cronica di sonno. Sulla base di queste evidenze si è ipotizzato che più che una mera associazione tra ADHD e problemi del sonno sarebbe più corretto concettualizzare l’ADHD come un “disturbo delle 24 ore”, ossia un disturbo che comporta alterazioni specifiche sia in fase di veglia sia in fase di sonno. Alcuni recenti studi elettrofisiologici hanno analizzato dei parametri elettroencefalografici (EEG) microstrutturali nei pazienti con ADHD, riscontrando delle alterazioni specifiche del disturbo. Questi parametri, fondamentalmente rappresentati dall’analisi quantitativa dell’EEG secondo le bande di frequenza delta, sigma e theta e l’analisi delle caratteristiche delle Slow Waves, sono direttamente associati a meccanismi di maturazione corticale e ai circuiti neurali coinvolti nella regolazione del sonno e potrebbero esser dunque dei marker tramite i quali approfondire l’associazione tra sonno e ADHD. Obiettivi dello studio : La nostra ipotesi di lavoro è che caratteristiche microstrutturali dell’EEG di sonno possano fungere da biomarker di parametri clinici dell’ADHD. Tali parametri includono le specifiche dimensioni psichiatriche e neuropsicologiche, e la risposta alla terapia farmacologica. L’obiettivo generale dello studio è individuare possibili marker EEG microstrutturali che possano aiutare a definire pazienti con ADHD a maggior rischio di comorbidità psichiatrica e ad indirizzare interventi diagnostici ed eventualmente terapeutici più precoci e mirati per prevenire gli esiti delle comorbidità sulla qualità della vita. Obiettivi specifici dello studio sono pertanto: 1) Caratterizzare retrospettivamente, in un campione di bambini e adolescenti con ADHD, la storia clinica con particolare attenzione al profilo psichiatrico. 2) Correlare i dati clinici rilevati con le caratteristiche spettrali dell’EEG di sonno dei pazienti afferenti al campione e con specifici parametri quantitativi relativi all’attività lenta del sonno, in particolare la pendenza (slope) delle onde lente (slow waves). Disegno dello studio: Sono stati analizzate retrospettivamente le cartelle cliniche di pazienti con diagnosi primaria o secondaria di ADHD di tipo combinato o prevalentemente iperattivo-impulsivo, formulata secondo i criteri DSM IV o DSM V, che hanno effettuato un EEG presso l’IRCCS Stella Maris nel periodo compreso tra gennaio 1999 e gennaio 2020. I criteri di inclusione erano i seguenti: - QI > 70 - Assenza di sindromi genetiche note - Assenza di lesioni cerebrali maggiori alla RM encefalo - Età gestazionale al parto superiore alla 32° settimana - Assenza di epilessia - Aver effettuato un EEG di sonno e veglia tramite registrazione con sistema digitale - Conoscenza della terapia farmacologica in corso al momento del EEG. Le registrazioni EEG durante il sonno sono state analizzate attraverso il software EEGLAB e scripts elaborati «ad hoc» su MATLAB (The Math Works Inc., Natick, MA) per il filtraggio di artefatti e di attività neurofisiologiche non di interesse (ad es., anomalie parossistiche). I valori delle potenze spettrali in banda delta (0.5 - 4 Hz), theta (4-7.5 Hz), alpha (8-13 Hz), beta (13-30 Hz), e sigma (12 - 15) in fase N2, e le caratteristiche specifiche delle slow waves in fase N2 e N3 (in particolare le slopes) sono state quindi correlate con i dati clinici raccolti. Popolazione in studio Sono stati arruolati 70 pazienti (58 maschi e 12 femmine) di età compresa tra i 3 e i 17 anni (media 8.76; DS 2.77). Le comorbidità con disturbi del neurosviluppo includevano 11 pazienti con disturbo dello spettro autistico, 15 con disturbo del linguaggio, 23 con disturbo dell’apprendimento e 14 con disturbo da tic. Le comorbidità con disturbi psichiatrici includevano 31 pazienti con disturbi dirompenti, 20 con disturbo dell’umore, 18 con disturbo d’ansia. Il pattern ipnico era valutabile in 49 pazienti: di questi 32 presentavano problematiche ipniche (difficoltà di addormentamento, risvegli notturni, sonno agitato). Di 52 pazienti è stato possibile raccogliere i dati dei questionari CBCL 6-18 compilati dai genitori. Di 47 pazienti è stato inoltre possibile raccogliere i dati dei questionari CPRS-R. Di 40 pazienti è stato raccolto il punteggio del QIT, di questi 21 avevano effettuato valutazione mediante scala WISC-IV e pertanto è stato possibile valutare le sottoscale (CV, RVP, ML e VE). Tutti i parametri clinici e testistici menzionati sono stati correlati statisticamente con i dati elettrofisiologici ottenuti dall’analisi microstrutturale dell’EEG di sonno, attraverso i software IBM© SPSS© SPSS versione 20 e RStudio_software

Diet of the Eurasian badger (&lt;em&gt;Meles meles&lt;/em&gt;) in an area of the Italian Prealps

&lt;strong&gt;Abstract&lt;/strong&gt; Samples of Eurasian badger faeces (n= 147) were collected at monthly intervals from October 1997 to December 1999 in an area of the Italian Prealps (58 km&amp;#178;), on the eastern coast of Lario (Como Lake). The altitude of the area ranged from 200 to 1300 m. Badger scats were analysed to estimate the relative volume and the frequency of occurrence of identifiable food items. Fruits, arthropodes, earthworms and mammals constituted the main food categories. Differences were found between the seasonal frequency of occurrences of arthropodes, earthworms and mammals, considering however that the small sample size in summer does not allow any definitive conclusions. The wide range of food items eaten by badgers and the seasonal differences would suggest that the badger is a "generalist" species which adopts an opportunist feeding strategy

Morphometric study on tadpoles of <em>Bombina variegata</em> (Linnaeus, 1758) (Anura; Bombinatoridae)

The tadpoles of Yellow-bellied toad (Bombina variegata) can be easily recognized from other Italian anuran species, except those of B. pachypus (though the two congeneric species are allopatric). In this paper we report morphometric data on B. variegata tadpoles from a Lombard population living near a torrent at 450 m a.s.l. On a sample of 264 tadpoles (stages 19-44, according to Gosner, 1960) we measured the following five variables: snout-vent length, tail length, maximum tail height, total length and weight. We found a slight allometric relationship between snout-vent length and tail length, while, as expectes,.the weight is nearly proportional to the cube of linear measures. According to literature data, our results point to highly constant proportions during the development phases up to prometamorphic stages. The ratio between snout-vent length and tail length was about 0.75 during the whole growing phase, while from stage 42 the proportion increases as the resorption of the tail starts

Fattori biochimici di regolazione dello sviluppo dello stelo fiorale della barbabietola da zucchero

Introduction. The development of the floral stem (bolting) in sugarbeet (Beta vulgaris L. subsp. vulgaris, Sugar Beet Group) is a problem that affects mostly the cultivations in southern Europe countries, where sowing is anticipated to early spring or autumn to allow plants to partly escape summer drought. One of the consequences of early sowing may be the exposure of the crop to low temperatures, resulting in plant vernalization and bolting induction. Such phenomenon is detrimental to crop yield because it lowers the sucrose reserves of the root and also enhances its fiber content, thus hampering processing quality. The physiology of bolting is regulated by several factors, both exogenous and endogenous. Among the latters, plant hormones and mainly gibberellins play a pivotal role, as it has been demonstrated for several species (Bernier et al., 1993; Blazquez et al., 1998; Gilmour et al., 1986; Zeevaart e Gage, 1993). According to our previous data, obtained during the first year of programmed work, gibberellins appear to stimulate floral stem elongation in sugarbeet. For this reason an investigation was undertaken, in order to deepen our knowledge on the identity and quantitative changes of the main gibberellin molecules characteristic of this species and to highlight correlations between gibberellins and floral stem development in two different plant genotypes. We then turned our attention to the physiological relations between two hormonal groups whose metabolism is strictly related in several species, i.e. auxins and gibberellins. We studied the putative role of the auxin indoleacetic acid in stimulating gibberellin biosynthesis and, as a consequence, its involvement in the control of bolting. To investigate more in depth the role of gibberellins in floral development, we studied the molecular regulation of their metabolism in two different plant genotypes, to assess its physiological relevance in the control of bioactive gibberellin levels and, consequently, in the regulation of bolting. Materials and methods. The concentration of the major gibberellins, both biologically active and biosynthetic precursors, was analyzed in apices and leaflets (30-60 mm length) of a vernalized (therefore committed to bolting) biennial cultivar ("Monodoro") and of an annual line ("CMS 7500"), both sampled before and at the starting of bolting. Concentration changes of GA19, GA20, GA5 and GA I were investigated. Changes of the concentrations of indoleacetic acid and of the aforesaid gibberellins were analyzed in sugarbeet samples analogous to those previously described. Analytical methods entailed HPLC purifications and hormone identification and quantification by GC-MS with the aid of deuterated internal standards. Molecular regulation of gibberellin metabolism was studied by analyzing the expression of the two sugarbeet genes encoding the main enzyme for gibberellin catabolism (GA 2-oxidase) in the apices from a commercial cultivar characterized by a high frequency of bolting and, subsequently, in a greenhouse-grown annual line, both sampled before and at the starting of bolting. Results and discussion. The most relevant results may be summarized as follows: it was confirmed that in sugarbeet the predominant branch of the biosynthetic pathway is the one involving early 13-hydroxylation of the precursor molecules; a correlation exists between the concentration of GA1 (which is known to enhance stem elongation) and bolting, because the hormone level is higher in bolting apices, particularly in the biennial cultivar; leaflets may be a source of gibberellin precursors, which could be translocated to apices; in these tissues, GA1 biosynthesis may be stimulated also by indoleacetic acid, whose concentration was 20-fold higher at the start of bolting than at the previous developmental stage; GA5 is the most abundant gibberellin in apices; although it does not directly stimulate stem elongation, the latter gibberellin might be involved in the precocious stage of flowering (floral induction), because of its high concentration in apices before bolting; in the latter stage, one of the two GA 2- oxidase genes is expressed at a lower level than at the beginning of bolting, which might be the cause for a lower catabolism (i.e. a rise of concentration) of those gibberellins putatively controlling floral stem development. Concerning GA5, several authors ascribe to this gibberellin, at least in a few species, a central role in floral induction: our data agree with such conclusions, because GA5 levels in apices are considerably high before bolting and drop thereafter. Conclusion. Present results highlight the relevance of gibberellins and of indoleacetic acid in bolting control of sugarbeet and suggest to develop our research to further investigate the physiological relevance of the control of metabolism of these growth regulators in floral development, with the aim to progress toward the comprehension of bolting control at both biochemical and molecular-genetic level