Biosynthesis of abscisic acid in fungi: identification of a sesquiterpene cyclase as the key enzyme in Botrytis cinerea

While abscisic acid (ABA) is known as a hormone produced by plants through the carotenoid pathway, a small number of phytopathogenic fungi are also able to produce this sesquiterpene but they use a distinct pathway that starts with the cyclization of farnesyl diphosphate (FPP) into 2Z,4E‐α‐ionylideneethane which is then subjected to several oxidation steps. To identify the sesquiterpene cyclase (STC) responsible for the biosynthesis of ABA in fungi, we conducted a genomic approach in Botrytis cinerea. The genome of the ABA‐overproducing strain ATCC58025 was fully sequenced and five STC‐coding genes were identified. Among them, Bcstc5 exhibits an expression profile concomitant with ABA production. Gene inactivation, complementation and chemical analysis demonstrated that BcStc5/BcAba5 is the key enzyme responsible for the key step of ABA biosynthesis in fungi. Unlike what is observed for most of the fungal secondary metabolism genes, the key enzyme‐coding gene Bcstc5/Bcaba5 is not clustered with the other biosynthetic genes, i.e., Bcaba1 to Bcaba4 that are responsible for the oxidative transformation of 2Z,4E‐α‐ionylideneethane. Finally, our study revealed that the presence of the Bcaba genes among Botrytis species is rare and that the majority of them do not possess the ability to produce ABA.     

INFLAM – INFLAMmation in Brain and Vessels with Iron Nanoparticles and Cell Trafficking: A Multiscale Approach of Tissue Microenvironment,Iron Nanostructure and Iron Biotransformation

Background

Inflammation is a share process in atherosclerosis and stroke and is thought to be a key player in the evolution of these diseases. Ten years ago, inflammation imaging with magnetic resonance imaging (MRI) was considered very promising for both pre-clinical and clinical studies of atherosclerosis and stroke.

Nonneutral evolution of tandem repeats in the mitochondrial DNA control region of lagomorphs

The mitochondrial DNA of the European rabbit (Oryctolagus cuniculus) contains a tandem array of 153-bp repeats in the vicinity of the replication origin of the H-stand. Variation among molecules in the number of these repeats results in inter- and intraindividual length polymorphism (heteroplasmy). Generally, in an individual, one predominant molecular type is observed, the others representing a low percentage of the mtDNA content. At the tissue level, we observe a particular distribution of this polymorphism in the gonads compared with liver, kidneys, or brain, implying a relationship between the differentiation status of the cells and the types of new mtDNA molecules which appear and accumulate during lifetime. Similar tandem repeats were also found in the mtDNA noncoding region of European hares (Lepus europaeus), a cottontail (Sylvilagus floridanus), and a pika (Ochotona rufescens). The lengths and the sequences of these units evolve rapidly and in a concerted way, but the number of repeats is maintained in a narrow range, and an internal 20-bp segment is highly conserved. Constraints restrict the evolution of the primary sequence of these repeated units, the number of which is probably controlled by a stabilizing selection.      

North African genes in Iberia studied by Y-chromosome DNA haplotype 5.

The frequency of haplotype 5 at the Y-chromosome-specific DNA polymorphism (p49/TaqI) was reported in a study of 487 males originating from five different geographic locations in Iberia and North Africa. The highest frequency of haplotype 5 (68.9%) was previously observed in Berbers from Morocco, and it has been established that this haplotype is a characteristic Berber haplotype in North Africa. The relative frequencies of haplotype 5 distribution show a geographical gradient of decreasing frequency according to latitude in Iberia: 40.8% in Andalusia, 36.2% in Portugal, 12.1% in Catalonia, and 11.3% in the Basque Country; such a cline of decreasing frequency of haplotype 5 from the south to the north in Iberia clearly establishes a gene flow from North Africa towards Iberia.     

The Effect of Persantin on Intercoronary Collateral Circulation and Survival During Gradual Experimental Coronary Occlusion: A Preliminary Report

Twenty-five dogs were exposed to gradual coronary occlusion by placing Ameroid constrictors around the origins of the left circumflex and anterior descending coronary arteries. Previous experiments have demonstrated that these constrictors absorb water and, over a period of three weeks, narrow the cross-sectional area of the two arteries to 50% or less, and consequently cause the death of 80% of the experimental animals. Twelve of the 25 animals were fed 50 mg. of Persantin three times a day by mouth commencing one day before the operative procedure. Determinations of the concentration of the drug in the blood revealed a level consistent with that obtained in humans after the administration of therapeutic doses. Eleven of the 13 control animals died in the three-month experimental period while only six of the 12 treated animals expired. Injections of Schlesinger mass in all animals dying or killed following the experimental period demonstrated that Persantin significantly accelerated the development of intercoronary anastomoses in the treated group, and in the surviving animals produced a rich anastomotic network much in excess of that seen in the surviving animals in the control series that were exposed to hypoxia alone. On the basis of these experimental findings, it is suggested that Persantin may favourably alter the prognosis of many patients with coronary artery disease.     

Haplotyping cryptic Adélie penguin taxa using low-cost,high-resolution melt curves

Distinguishing morphologically cryptic taxa, by definition, requires genetic data such as DNA sequences. However, DNA sequences may not be obtained easily for taxa from remote sites. Here we provide the details of a high-resolution melt-curve-based method using taxon-specific primers that can distinguish two taxa of Adélie penguins, and that will be usable in Antarctica when combined with some of the newly developed field-deployable thermal cyclers. We suggest that the wider adoption of field-deployable polymerase-chain-reaction-based techniques will enable faster assignation of haplotype to individuals in situ, and so allow the targeting of observations and sample collection to specimens relevant to the research question. Targeting individuals will also reduce the need to repeatedly handle animals and reduce the time and travel required to complete field work.