Floral resource availability declines and florivory increases along an elevation gradient in a highly biodiverse community.

BACKGROUND AND AIMS: Flower-visitor interactions comprise a continuum of behaviors, from mutualistic partners to antagonistic visitors. Despite being relatively frequent in natural communities, florivory remains unexplored, especially when comprising abiotic factors, spatio-temporal variations and global environmental changes. Here, we addressed the variation of florivory driven by changes in elevation and temporal flower availability. We expect decreased floral resources as elevation increases -due to environmental constraints- which may affect plant-florivore interactions. Yet, if floral resources decrease but florivores remain constant, then we may expect an increase in florivory with increasing elevation in the community. METHODS: The flowering phenology of plant individuals was recorded in the Neotropical campo rupestre vegetation, in southeastern Brazil. Damages by florivores were recorded in plots at elevations ranging from 823 to 1411 m using two response variables as a proxy for florivory: the proportion of attacked flowers per plant and the proportion of petal removal on single flowers. KEY RESULTS: Flower attack increased with elevation and damages were intensified in species with longer flowering periods. Conversely, longer flowering periods resulted in higher levels of petal removal when decreasing elevation. The temporal availability of flowers affected florivory, with the proportion of attacked flowers being more intense when there are less flowered individuals in the community. Petal removal on single flowers was intensified in plots with a larger number of individuals flowering, and with more species co-flowering. CONCLUSIONS: This study brings one of the broadest records of a commonly neglected interaction of insects feeding on floral structures, quantifying the combined effect of floral display and availability along an elevation gradient in a highly biodiverse mountaintop community. These findings contribute to filling in the gap in the understanding of florivory dynamics, focusing on a tropical mountaintop scenario facing imminent environmental changes and excessive natural resource exploitation.

Is chemodenervation with incobotulinumtoxinA an alternative to invasive chronic anal fissure treatments?

BACKGROUND: Botulinum toxin type A is currently strongly recommended for the treatment of anal fissures (AFs). However, there is still no consensus on dosage or injection technique. This study provides further efficacy and safety evidence in a 2-year follow-up. METHOD: Prospective, open-label, single-arm, single-center study carried out in adult patients with AFs non-responsive to previous treatments. Patients were treated with incobotulinumtoxinA (incoBoNT/A) injected in both laterals and posterior intersphincteric groove. Healing rate at 2 years was the primary endpoint. Secondary endpoints included internal anal sphincter pressures, incontinence, and safety. RESULTS: A total of 49 patients were treated with a mean incoBoNT/A dose of 40.5 U (spread across three locations). Healing rate at 2 years was 83.9% with a 24.5% of recurrence throughout the study. Only 7 patients (14.3%) reported adverse events (AEs) that were mild and temporary. Mean reduction in anal resting pressure was -9.1 mmHg at 3 months (p = 0.001). Mean reduction in voluntary squeeze pressure was -27.5 mmHg at 3 months (p < 0.001). Mean pain perception measured with a visual analog scale decreased by -6.5 points at 2 years (p < 0.001). There was an incontinence increase at 1 month of 1.3 points (p = 0.006), but baseline values were restored at 6 months. CONCLUSION: We present results that support the use of incoBoNT/A as a second line for AFs that do not respond to ointment therapy. IncoBoNT/A injection is a less invasive treatment that should be considered before surgery due to its efficacy and its safety which includes no permanent impairment. TRIAL REGISTRATION: ISRCTN90354265; Registered on 16th February 2024. Retrospectively registered.

Inhibition of glucagon secretion by diazoxide in vitro.

UNLABELLED: The effect of diazoxide on the secretion of glucagon and insulin was studied using the isolated perfused rat pancreas. The perfusate concentration of D-glucose was kept constant at 5.6 mM. Five secretagogues of both glucagon and insulin--10 mM L-arginine, 5 mM L-leucine, 1.4 muM prostaglandin F2alpha, 100 nM bovine growth hormone, and 10 nM theophylline--were administered individually in the presence or absence of 325 muM diazoxide. Basal secretion of glucagon or insulin was not discernibly affected by diazoxide. With diazoxide the secretion of glucagon was (a) abolished completely in response to L-arginine or L-leucine; (b) inhibited partially in response to prostaglandin F2alpha; (c) unaltered in response to growth hormone; and (d) unchanged or, at times, enhanced in response to theophylline. On the other hand, the secretion of insulin induced by each of these agents was inhibited effectively by diazoxide. CONCLUSIONS: (a) Diazoxide inhibits the secretion of glucagon as well as insulin in response to certain secretagogues independent of any changes in prevailing levels of glucose. (b) At the concentration tested, diazoxide is a more potent and consistent inhibitor of the release of insulin than of glucagon.

L-Leucine-induced secretion of glucagon and insulin, and the "off-response" to L-leucine in vitro. I. Characterization of the dynamics of secretion.

The effects of L-leucine, D-leucine, and L-isoleucine upon the secretion of glucagon and insulin were investigated using the isolated, perfused rat pancreas. All experiments were conducted in the presence of 5.6 mM D-glucose. Ten-minute perfusions of 2, 5, and 10 mM L-leucine induced the release of glucagon and insulin in a dose-related manner. The removal of L-leucine was followed by renewed release of insulin ("off-response") but not of glucagon. The magnitude of the off-response was greater when L-leucine was perfused over longer periods. L-Isoleucine evoked the release of both glucagon and insulin. When L-leucine was administered during perfusion of L-isoleucine, L-leucine-induced release of glucagon was inhibited, that of insulin was augmented, and the insulin off-response prevailed. When the perfusion of L-leucine immediately preceded that of L-isoleucine, L-isoleucine-induced release of glucagon was abolished and that of insulin was augmented. D-Leucine evoked the release of glucagon but not of insulin, and no off-response occurred. When the perfusion of D-leucine followed that of L-leucine, D-leucine-induced glucagon release was inhibited; the insulin off-response to L-leucine was not altered. We reached the following conclusions. 1) Glucagon release induced by L-leucine, D-leucine, or L-isoleucine is likely to be related to the occupancy by these analogous amino acids of transport and/or receptor sites which they share. 2) The insulin off response to L-leucine seems to be evoked by events which take place during the period of administration of L-leucine; these events are not likely to be the release of insulin that occurs during perfusion of L-leucine or the transport of L-leucine into or out of the beta cell. 3) Structurally or chemically similar compounds which are secretagogues both for glucagon and insulin affect the release of these hormones in different ways; these differences are likely to be due to dissimilar mechanisms governing the secretion of the two hormones.

Studies on precellular evolution: the encapsulation of polyribonucleotides by liposomes.

Liposomes are 5 to 50 micron vesicles with an internal aqueous environment, whose amphiphilic lipidic components self-assemble into systems with at least one double-layered membrane. Liposomes have been suggested as possible models of precellular systems formed in the early Archean Earth from lipids of non-enzymatic origin. Since it is generally accepted that RNA molecules preceded double-stranded DNA molecules as genetic material, we have studied the encapsulation of polyribonucleotides within liposomes made from dipalmitoyl phosphatidylcholine, and from egg yolk phosphatidylcholine to which cholesterol was added in some cases. The liposomes were prepared under anoxic conditions following the reverse phase evaporation method described by Szoka and Papahadjopoulos. Quantitative determinations show that approximately 50% of the available lipids form liposomes, and that up to 5% of the polyribonucleotides can be entrapped by them. We have also studied the encapsulation of polyribonucleotides in the presence of 1) urea and cyanamide, two non-electrolytes that have been used as prebiotic condensing agents, and 2) of Zn++ and Pb++, two cations employed in the non-enzymatic template-directed synthesis of polyribonucleotides from activated nucleotides.

Combined test + inhibin A at week 13 in contingent sequential testing: an interesting alternative for first-trimester prenatal screening for Down syndrome.

OBJECTIVE: To analyze various possibilities of using dimeric inhibin A (DIA) as a first-trimester marker, during week 13, for diverse sequential strategies together with the combined test (CT) [which uses pregnancy-associated plasma protein A, free beta-human chorionic gonadotrophin and nuchal translucency]. METHOD: We analyzed three sequential strategies (nondisclosure, stepwise and contingent) for measuring DIA in week 13. Multivariate Gaussian modelling was used to estimate second-trimester, false-positive and detection rates. Model parameters were taken from the Serum, Urine and Ultrasound Screening Study (SURUSS) assay. RESULTS: The three sequential strategies provided high and comparable levels of effectiveness, with false-positive rate for fixed detection rate of 85% and detection rate for fixed false-positive rate of 5% values of about 91 and 2%, respectively. The contingent strategy (with two CT risk cutoffs, of 1 in 50 and 1 in 2000) produced a screening-positive rate of 0.8% with CT, while only 23% of the women needed subsequent DIA measurement. CONCLUSIONS: First-trimester sequential screening using CT together with DIA measurement in week 13 is capable of producing results that are comparable with those of the integrated test, with the additional advantage that the final result is obtained earlier. It is recommended that this strategy be evaluated in large-scale prospective studies.

Delta-NT and center-specific ultrasound nuchal translucency medians.

OBJECTIVES: Two methods have been proposed for standardizing measures of nuchal translucency thickness (NT) for risk calculation in first-trimester screening for chromosomal defects: differential delta NT (delta-NT) and multiples of the median (MoM) of NT. There is currently some debate as to which of these is more appropriate. The aims of this study were to determine whether delta-NT could be extrapolated successfully from one center-specific NT reference curve to another and thus to empirically calculate the likelihood ratios (LRs) of delta-NT. METHODS: This was a retrospective analysis of a database of 4248 singleton pregnancies, including 13 cases of Down syndrome. The delta-NT was extrapolated to the reference curve of the NT values of the original group of patients for whom the LRs were calculated empirically, using a scale factor. The Down syndrome risk was calculated by standardizing the NT, using both extrapolated delta-NT and MoM methods, both for the screening based on maternal age and NT alone, and for the combined screening, in which biochemical markers are also taken into account. We analyzed detection rates and false positives, the precision of the risk prediction obtained by each of the methods and the effectiveness when each of the methods was used with a cut-off point based on a fixed post-test risk. RESULTS: The risk calculation using extrapolated delta-NT presented an effectiveness profile that was similar to that obtained using MoMs, both when NT was used as the sole marker and when it was used in combination with biochemical markers. The precision of the risk prediction was similar with both methods. CONCLUSIONS: Delta-NT can be extrapolated for use in risk calculation between two populations with different distributions and medians of NT values. The precision of the risk estimate obtained is similar to that derived using MoMs.

Incidência da carne PSE (pale, soft, exsudative) em suínos em razão do tempo de descanso pré-abate e sexo / Resting time pre-slaughter and sex on the incidence of PSE (pale, soft, exsudative) meat in pigs

Avaliou-se o efeito do período de descanso pré-abate e do sexo sobre a incidência de carne PSE (pale, soft, exudative) em suínos. Foram realizadas três visitas a abatedouro comercial, nas quais se mensurou o pH das carcaças (n=2128) aos 45 minutos após o abate, de lotes compostos por fêmeas, machos castrados cirurgicamente e machos imunocastrados e de lotes mistos (fêmeas e machos castrados cirurgicamente), submetidos a período de descanso que variou de duas a 16 horas. Carcaças com pH45≤5,8 foram classificadas como PSE, e com pH45>5,8 como normais. Em função do número de animais avaliados dentro de cada categoria, estimou-se a frequência de carne PSE. A incidência total de carne PSE foi de 10,1%, sendo maior nos lotes de animais imunocastrados (13,5%) quando comparados aos lotes de fêmeas (8,6%) ou de machos castrados cirurgicamente (8,5%). Períodos de descanso menores que seis horas e acima de 14 horas aumentaram a incidência de carne PSE. Período de descanso entre seis e oito horas minimizaram a ocorrência de carnes PSE.

Were evaluated the effect of lairage pre-slaughter and sex on the incidence of PSE (pale, soft and exudative) meat in pigs. There were three visits to a commercial slaughterhouse, in which the pH of carcasses (n=2128) was measured at 45 minutes after slaughter of lots consisting exclusively of females, males castrated surgically, males immunologically castrated and mixed lots (females and castrated surgically) underwent a resting time, and time between the shipment and slaughter ranged from two to 16 hours. Carcasses with pH45≤5.8 were classified as PSE and with pH45>5.8 as normal. Depending on the number of animals evaluated in each category we estimated the frequency of PSE. The overall incidence of PSE meat was 10.1%, higher in lots of animals immunocastrated (13.5%) compared to lots of females (8.6%) or castrated males (8.5%). Resting time of less than six hours and up to 14 hours increased the incidence of PSE meat. Resting time between six and eight hours minimized the occurrence of PSE meat.

Cerebellar N-acetyl-beta-D-glucosaminidase: a study of the enzyme in bulk-isolated purkinje and granule cells.

The specific activity of the lysosomal glycosidase N-acetyl-beta-D-glucosaminidase was determined in Purkinje cell bodies and granule cells isolated in bulb from cerebella of 13-, 15- and 18-day-old rats, and somewhat higher values were found for the enzyme in the Purkinje cell bodies. Although the pH profile of N-acetyl-beta-D-glucosaminidase in both neuronal types was similar, the activity in the granule cells exhibited two "pH optima". The glycosidase could be readily solubilized from both neuronal types by repeated freezing and thawing and, upon sedimentation in sucrose density gradients, the solubilized activity appeared as two distinct molecular components. The findings demonstrate the feasibility of detailed and direct comparative studies of neuron-specific patterns of enzymatic development and the excellent suitability of bulk-isolated cells for this purpose.

Synthesis of putrescine under possible primitive Earth conditions.

The synthesis of putrescine was accomplished by decarboxylation of L-ornithine when this amino acid was heated in aqueous solution and in the absence of oxygen. Chromatographic, radioisotopic, and enzymatic techniques were used to demonstrate that one mole of non-radioactive putrescine and one mole of 14CO2 was formed during the heating of L-(l-14C)-ornithine. This work indicates that the synthesis of putrescine can occur starting with ornithine and in conditions that are presumed could have existed on the primitive Earth. The possible significance of these results in the prebiotic molecular evolution is briefly discussed.

Diffusion of Mn2+ ions into liposomes mediated by phosphatidate and monitored by the activation of an encapsulated enzymatic system.

Transbilayer diffusion of Mn2+ ions occurred in liposomes formed from dipalmitoyl-phosphatidylcholine or egg-yolk phosphatidylcholine and egg-yolk phosphatidate (molar ratio 2:1) containing DNA and DNase I within their aqueous compartments. Cation diffusion was demonstrated by the hydrolytic activity of DNase I, activated by the Mn2+ ions that diffused into the vesicles, and this was confirmed by light scattering. Phosphatidate, a cone-shaped lipid which has been synthesized under simulated prebiotic conditions, was necessary for cation diffusion across the liposome membranes. Such liposomes represent a simple precellular system that interchanges cations with the surroundings and provides a microenvironment for enzymatic reactions, as evidenced by the hydrolysis of DNA by DNase I inside these closed lipid compartments.