Chilling outweighs photoperiod in preventing precocious spring development

It is well known that increased spring temperatures cause earlier onset dates of leaf unfolding and flowering. However, a temperature increase in winter may be associated with delayed development when species' chilling requirements are not fulfilled. Furthermore, photosensitivity is supposed to interfere with temperature triggers. To date, neither the relative importance nor possible interactions of these three factors have been elucidated. In this study, we present a multispecies climate chamber experiment to test the effects of chilling and photoperiod on the spring phenology of 36 woody species. Several hypotheses regarding their variation with species traits (successional strategy, floristic status, climate of their native range) were tested. Long photoperiods advanced budburst for one‐third of the studied species, but magnitudes of these effects were generally minor. In contrast to prior hypotheses, photosensitive responses were not restricted to climax or oceanic species. Increased chilling length advanced budburst for almost all species; its effect greatly exceeding that of photoperiod. Moreover, we suggest that photosensitivity and chilling effects have to be rigorously disentangled, as the response to photoperiod was restricted to individuals that had not been fully chilled. The results indicate that temperature requirements and successional strategy are linked, with climax species having higher chilling and forcing requirements than pioneer species. Temperature requirements of invasive species closely matched those of native species, suggesting that high phenological concordance is a prerequisite for successful establishment. Lack of chilling not only led to a considerable delay in budburst but also caused substantial changes in the chronological order of species' budburst. The results reveal that increased winter temperatures might impact forest ecosystems more than formerly assumed. Species with lower chilling requirements, such as pioneer or invasive species, might profit from warming winters, if late spring frost events would in parallel occur earlier.     

Development of a bioadhesive nanoformulation with Glycyrrhiza glabra L. extract against Candida albicans

Abstract

Glycyrrhiza glabra L. is considered an important source of bioactive compounds. This study aimed at the development of an efficient solution for the treatment of oral candidiasis. Several extracts of Glycyrrhiza glabra L. were prepared using different solvents and their potential in vitro antifungal activity was assessed. Ethanolic extracts showed the most promising results against C. albicans. This extract was incorporated into mucoadhesive nanoparticles (PLA, PLGA and alginate), which were further included in an oral gel, an oral film and a toothpaste, respectively. The results showed that nanoparticles were successfully produced, presenting a mean size among 100–900?nm with high encapsulation efficiency. In vitro studies showed that the most bioadhesive formulation was the oral film with extract-loaded PLGA nanoparticles, followed by the toothpaste with extract-loaded alginate nanoparticles and the oral gel with extract-loaded PLA nanoparticles.     

Baroreceptor reflex control of heart rate in rats studied by induced and autogenic changes in arterial pressure

The function of the arterial baroreflex has traditionally been assessed by measurement of reflex changes in heart rate (HR) or sympathetic nerve activity resulting from experimenter-induced manipulation of arterial blood pressure (the Oxford method, also termed the pharmacological method). However, logistical and flexibility limitations of this technique have promoted the development of new methods for assessing baroreflex function such as the evaluation of changes in spontaneous arterial pressure and HR. Although this new spontaneous method has been validated in dogs and humans, it has not been rigorously tested in rats. In the present study, the method of correlating spontaneous changes in systolic blood pressure and HR was evaluated in resting, normotensive Sprague-Dawley rats. This technique was found to be neither reliable nor valid under the conditions employed in the present protocol. We also tested a variation of the spontaneous method that evaluates particular sequences of data during which arterial pressure and pulse interval are changing in the same direction for at least three consecutive heartbeats (the sequence method). The sequence method did not provide extra reliability or validity over the spontaneous method. We conclude that due to the restricted range of variability obtained by measuring spontaneous blood pressure fluctuations, the spontaneous and sequence techniques do not provide data that are comparable to the traditional method of assessing HR changes triggered by arterial blood pressure increases and decreases induced by vasoactive drugs. However, it is possible that surgical stress obscured the relationship between blood pressure and HR, and therefore additional studies are needed to determine whether the spontaneous and sequence methods can be applied to rats during different behavioral states.     

Motor neuropathy‐associated mutation impairs Seipin functions in neurotransmission

Gain‐of‐toxic‐function mutations in Seipin (Asparagine 88 to Serine (N88S) and Serine 90 to Leucine (S90L) mutations, both of which disrupt the N‐glycosylation) cause autosomal dominant motor neuron diseases. However, the mechanism of how these missense mutations lead to motor neuropathy is unclear. Here, we analyze the impact of disruption of N‐glycosylation of Seipin on synaptic transmission by over‐expressing mutant Seipin in cultured cortical neurons via lentiviral infection. Immunostaining shows that over‐expressed Seipin is partly colocalized with synaptic vesicle marker synaptophysin. Electrophysiological recordings reveal that the Seipin mutation significantly decreases the frequency, but not the amplitudes of miniature excitatory post‐synaptic currents and miniature inhibitory post‐synaptic currents. The amplitude of both evoked excitatory post‐synaptic currents and inhibitory post‐synaptic current is also compromised by mutant Seipin over‐expression. The readily releasable pool and vesicular release probability of synaptic vesicles are both altered in neurons over‐expressing Seipin‐N88S, whereas neither γ‐amino butyric acid (GABA) nor α‐Amino‐3‐hydroxy‐5‐methyl‐4‐ isoxazolepropionic acid (AMPA) induced whole cell currents are affected. Moreover, electron microscopy analysis reveals decreased number of morphologically docked synaptic vesicles in Seipin‐N88S‐expressing neurons. These data demonstrate that Seipin‐N88S mutation impairs synaptic neurotransmission, possibly by regulating the priming and docking of synaptic vesicles at the synapse.

     

Treatment of dairy cows with PGF2alpha or NSAID, in combination with antibiotics, in cases of postpartum uterine inflammation

ABSTRACT: BACKGROUND: The aim of the study was to test the effect of two treatments in cases of acute puerperal metritis (APM) and clinical metritis (CM). METHODS: Cows with APM and CM (n = 40)) were matched according to plasma fibrinogen levels (Fb) into three groups. Two negative control groups D (n = 11) and E (n = 17) were composed of healthy cows. The proportion of animals with APM and CM was similar within the groups. Treatment was started on the 3rd day postpartum (PP). In group A (n = 15), intramuscular (i.m.) administration of ceftiofur was used for five days in combination with flunixin for three days. Group B (n = 15) received i.m. administration of ceftiofur for five days followed by two injections of prostaglandin F2alpha, with an interval of 8 h, on the 8th day PP. Group C (n = 10) served as a control group with no treatment. The general health status, body temperature (BT) and vaginal discharge were evaluated daily. Endometrial biopsies for bacteriology were taken once a week for seven weeks PP. Blood samples for the analysis of acute phase proteins were collected once a week for six weeks PP. Samples for progesterone analysis were taken twice a week for seven weeks PP. Fertility performance data were recorded. RESULTS: The area under the curve of BT was higher in group B than in group D cows (P < 0.05). No differences were found for vaginal discharge. There were no differences in bacterial growth, start of ovarian activity or serum amyloid-A or fibrinogen levels among the groups. The haptoglobin concentration was higher in the first and second weeks PP in group B compared with the other groups (P < 0.05). The number of days open was higher in group A than in both groups B and D (P < 0.05). The pregnancy rate after the first two services was higher (P < 0.05) in groups B and D than in groups A and C. The number of services per pregnancy was lower in group B than in group C (P < 0.05). CONCLUSIONS: Regardless of more severe uterine inflammation found in animals from group B, these cows showed the same fertility parameters as healthy animals.     

Structure of the Mitochondrial Aminolevulinic Acid Synthase,a Key Heme Biosynthetic Enzyme

1. Download high-res image (269KB)
2. Download full-size image

     

Altered infant feeding patterns in boys with acquired nonsyndromic cryptorchidism

BACKGROUND : Genetic and environmental factors likely influence susceptibility to nonsyndromic cryptorchidism, a common disease presenting at birth or in later childhood. We compared cases and controls to define differential risk factors for congenital versus acquired cryptorchidism. METHODS : We compared questionnaire and clinical data from cases of congenital cryptorchidism (n = 230), acquired cryptorchidism (n = 182) and hernia/hydrocele (n = 104) with a group of healthy male controls (n = 358). Potential predictor variables (p < 0.2 in univariable analysis) were included in stepwise multivariable logistic regression models. RESULTS : Temporary (odds ratio [OR], 0.5; 95% confidence interval [CI], 0.4–0.8) or exclusive (OR, 0.6; 95% CI, 0.4–0.9) breastfeeding was reduced and soy formula feeding increased (OR, 1.8; 95% CI, 1.2–2.9) in acquired but not congenital or hernia/hydrocele groups. The highest risk estimates were observed for primary soy formula feeding with limited or no breastfeeding (OR 2.5; 95% CI, 1.4–4.3; adjusted OR, 2.7; 95% CI, 1.4–5.4) in the acquired group. Primary feeding risk estimates were equivalent or strengthened when multivariable models were limited to age greater than 2 years, full‐term or not small for gestational age, or Caucasian subjects. Pregnancy complications and increased maternal exposure to cosmetic or household chemicals were not consistently associated with either form of cryptorchidism in these models. CONCLUSIONS : Our data support reduced breastfeeding and soy formula feeding as potential risk factors for acquired cryptorchidism. Although additional studies are needed, hormonally active components of breast milk and soy formula could influence the establishment of normal testis position in the first months of life, leading to apparent ascent of testes in childhood. Birth Defects Research (Part A), 2012. © 2012 Wiley Periodicals, Inc.     

Heterotopic Cervical Heart Transplantation in Mice

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies this model by avoiding challenging suture anastomoses of small vessels thereby reducing warm ischemia time. In comparison to abdominal graft implantation the cervical model is less invasive and the implanted graft is easily accessible for further follow-up examinations. Anastomoses are performed by pulling the ascending aorta of the graft over the cuff with the recipient’s common carotid artery and by pulling the main pulmonary artery over the cuff with the external jugular vein. Selection of appropriate cuff size and complete mobilization of the vessels are important for successful revascularization. Ischemia-reperfusion (I/R) injury can be minimized by perfusing the graft with a cardioplegic solution and by hypothermia. In this article, we provide technical details for a simplified and improved cuff technique, which should allow surgeons with basic microsurgical skills to perform the procedure with a high success rate.     

High temporal and individual variation in the prevalence and intensity of chytrid infection in the southernmost Leaf Frog of the genus Pithecopus (Anura,Phyllomedusidae)

Hydrobiologia - Pithecopus rusticus is an endemic amphibian restricted to the type locality, in southern Brazil, and possibly endangered to extinction, due to habitat degradation. However, an...     

A comparison of the wood anatomy of 11 species from two cerrado habitats (cerrado s.s. and adjacent gallery forest)

A comparative study of the secondary xylem (wood) anatomy of 11 species (38 specimens) occurring in cerrado s.s. and the adjacent gallery forest (both cerrado s.l. habitat) was made with the aim of identifying the anatomical characteristics of ecological value and correlating them with the environmental conditions. The anatomical features that vary, in general, between the two habitats are: growth ring distinctness (well or poorly defined); tyloses and deposits (more abundant in cerrado specimens); gelatinous fibres (more evident in cerrado specimens and in different patterns between habitats); variation in paratracheal and banded parenchyma (more abundant in cerrado); and more cells per parenchyma strand in cerrado. In general, gallery forest specimens have wider vessels, fewer vessels per square millimetre and larger intervessel pits, indicating more efficient water conduction, whereas cerrado s.s. specimens are the opposite, with low vulnerability and mesomorphy indices, demonstrating greater safety under conditions of water stress. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ?? , ??–??.