Seeded breadfruit naturalized in the Caribbean is not a seeded variety of Artocarpus altilis

In the past, phenotypic resemblances between three species and natural hybrids belonging to the genus Artocarpus were a source of confusion between individuals belonging to these taxons. Now, results of amplified fragment length polymorphism analysis and morphological data concerning a great diversity of breadfruit are being published. We have considered historical data about the naturalization of breadfruit in the Caribbean, the number of seed per fruit in the seeded breadfruit cultivated in the Caribbean, and scientific knowledge about breadfruit published today. We have established that the seeded breadfruit grown in the Caribbean is in fact Artocarpus camansi Blanco (1837), recognized as a seeded wild ancestor of the domesticated breadfruit, and not a seeded variety of Artocarpus altilis [synonym Artocarpus incisa] as established by Duss (1897), still often referred to by modern authors.     

Ultrasonographic and computed tomographic features of a true gastro-gastric intussusception with concurrent foreign bodies in a dog

A 2-year-old intact male Cane Corso dog was presented for acute weakness, vomiting, and diarrhea. Abdominal ultrasound revealed the stomach had severe wall edema and a target appearance. Computed tomography was consistent with a gastro-gastric intussusception and concurrent mineral-like gastric foreign bodies. After reduction of the intussusception, bilateral incisional gastropexy was performed to prevent recurrence. True gastrogastric intussusception is a rare condition and should be considered if the stomach has severe wall edema with a target sign on abdominal ultrasound. Computed tomography was useful to confirm this rare diagnosis and screen the entire abdomen for concurrent lesions.Key clinical message:This case highlights the usefulness of a CT examination to confirm this rare diagnosis, to determine the position of gastric compartments, and to detect potential concurrent lesions prior to surgery.     

Comparison of direct and indirect genetic methods for estimating seed and pollen dispersal in Fagus sylvatica and Fagus crenata

The comparison between estimates of historical gene flow, using variance in allelic frequencies, and estimates of contemporary gene flow, using parentage assignment, is expected to provide insights into ecological and evolutionary processes at work within and among populations. Genetic variation at microsatellite loci was used to quantify genetic structure in two wind pollinated, gravity and animal-dispersed tree species (Fagus sylvatica L. and Fagus crenata Blum.) and to derive historical estimates of gene flow. The gene dispersal distances estimated assuming effective population density to be 1/4 of the observed density were ∼77 m in European beech and ∼40 m in Japanese beech. Parentage analyses and a neighbourhood model approach were used to estimate contemporary patterns of seed and pollen dispersal. Our results suggest restricted seed dispersal abilities in both European beech (δ_s = 10.5 m) and Japanese beech (δ_s = 12.4 m), with an exponential shaped seed dispersal kernel. A non-negligible rate of seed immigration (m_s = 27%) was detected in European beech sites but not in Japanese beech site. Pollen dispersal within studied sites also appeared limited (δ_p = 41.63 m in European beech and δ_p = 79.4 m in Japanese beech), despite high rate of pollen immigration (m_p = 68% in European beech and m_p = 40% m in Japanese beech). Interestingly, contemporary and historical estimates of gene flow were within the same order of magnitude (a few tens of meters).     

The Hedgehog pathway promotes blood-brain barrier integrity and CNS immune quiescence

The blood-brain barrier (BBB) is composed of tightly bound endothelial cells (ECs) and perivascular astrocytes that regulate central nervous system (CNS) homeostasis. We showed that astrocytes secrete Sonic hedgehog and that BBB ECs express Hedgehog (Hh) receptors, which together promote BBB formation and integrity during embryonic development and adulthood. Using pharmacological inhibition and genetic inactivation of the Hh signaling pathway in ECs, we also demonstrated a critical role of the Hh pathway in promoting the immune quiescence of BBB ECs by decreasing the expression of proinflammatory mediators and the adhesion and migration of leukocytes, in vivo and in vitro. Overall, the Hh pathway provides a barrier-promoting effect and an endogenous anti-inflammatory balance to CNS-directed immune attacks, as occurs in multiple sclerosis.     

Irradiance-induced plasticity in the hydraulic properties of saplings of different temperate broad-leaved forest tree species

We assessed the irradiance-related plasticity of hydraulic architecture in saplings of Betula pendula Roth., a pioneer species; Acer pseudoplatanus L., Fraxinus excelsior L. and Quercus robur L., which are post-pioneer light-requiring species; and Quercus petraea Matt. Liebl. and Fagus sylvatica L. Plants were grown in pots in 36%, 16% and 4% of full sunlight. Hydraulic conductance was measured with a high-pressure flow-meter in entire, in situ root systems and in excised shoots. Leaf-specific whole-plant conductance (LSC) increased with irradiance, due, in part, to an effect of irradiance on plant size. In addition, there was a size-independent effect of irradiance on LSC due, in part, to an increase in root hydraulic conductance paralleled by an increase in root biomass scaled to leaf area. Changes in shoot conductivity also contributed to the size-independent plasticity of LSC. Vulnerability to cavitation measured in current-year twigs was much larger in shade-grown plants. Betula pendula had the highest whole-plant, root and shoot conductances and also the greatest vulnerability to cavitation. The other species were similar in LSC, but showed some variation in root conductance scaled to biomass, with Q. robur, Q. petraea and F. sylvatica having the lowest root conductance and susceptibility to cavitation. All species showed a similar irradiance-related plasticity in LSC.