Molecular systematics in the genus Mucor with special regards to species encountered in cheese

The genus Mucor, a member of the order Mucorales, comprises different species encountered in cheeses. Although fungi play a fundamental role in cheese manufacturing and ripening, the taxonomy of many fungal species found in cheese is poorly defined; indeed, this is the case for Mucor spp. In the present study, we assessed the phylogenetic relationships among 70 Mucor strains, including 36 cheese isolates, by using a five gene phylogenetic approach combined with morphological analyses. Overall, at least six species of Mucor were identified among the cheese isolates including a possible new taxon. The present study also suggests that the genus Mucor comprises undescribed taxa and needs to be properly defined.     

Activity-Dependent Dendritic Release of BDNF and Biological Consequences

Network construction and reorganization is modulated by the level and pattern of synaptic activity generated in the nervous system. During the past decades, neurotrophins, and in particular brain-derived neurotrophic factor (BDNF), have emerged as attractive candidates for linking synaptic activity and brain plasticity. Thus, neurotrophin expression and secretion are under the control of activity-dependent mechanisms and, besides their classical role in supporting neuronal survival neurotrophins, modulate nearly all key steps of network construction from neuronal migration to experience-dependent refinement of local connections. In this paper, we provide an overview of recent findings showing that BDNF can serve as a target-derived messenger for activity-dependent synaptic plasticity and development at the single cell level.     

Demographic crash associated with high parasite load in an experimental roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis>) population

In March 2002, ten roe deer (Capreolus capreolus) were released in a partly wooded 14.2-ha enclosure to investigate the effect of high population density on vegetation cover and demographic parameters. However, in mid 2003, five animals died after rapid emaciation. Two other deer were killed to carry out further post-mortem examination. In addition to a general loss of body mass and injuries in males caused by the healthiest of them, we found a high level of parasitism. The remaining animals received anti-parasite treatment, and four other treated roe deer were added into the enclosure. All the deer were then captured and treated against parasites twice a year, the fawns being removed when first captured. Four years after the crash, the population seemed healthy: deaths no longer occurred; mean adult body mass reached 27.6 kg in March; females produced on average 1.6 fawns per year, with a mean body mass of 13.8 kg in October and 16.7 kg in March. Furthermore, undergrowth cover changed little since March 2004. These results suggest that outbursts of parasites may cause population crashes in high-density situations before the onset of nutritive stress and may explain certain cases of ‘abnormal’ (massive) mortality recorded in roe deer.     

Early effects of the mutation laurina on the functioning and size of the shoot apex in coffee tree and analysis of the plastochron phases: relationships with the dwarfism of leaves

The current article presents the investigations into the effect of the laurina mutation on the functioning and size of the shoot apical meristem (SAM) in Coffea arabica. This monolocus and Mendelian mutation is known to have pleiotropic effects on tree shape and dwarfism. A comparison between the wild type C. arabica var. Bourbon and its natural dwarf mutant C. arabica var. laurina, also called Bourbon pointu, was carried out leading to three main results: (1) the effects appeared immediately after the emergence of the buttress but did not affect the dome-shaped SAM (size and shape); (2) the effects were located at the peripheral zone and maintained subsequently within the leaf primordia; (3) the effects consisted of reduction in both the size of primordia and the height of incipient internode, consequently resulting in dwarfism of mature leaves and internodes. By contrast, the laurina mutation had no effect on the relationship between the phyllochron and the plastochron, the decussate and opposite phyllotaxis, and the relative timing of SAM functioning within the plastochron.     

Validation of reference genes for quantitative expression analysis by real-time RT-PCR in Saccharomyces cerevisiae

Background  

Real-time RT-PCR is the recommended method for quantitative gene expression analysis. A compulsory step is the selection of good reference genes for normalization. A few genes often referred to as HouseKeeping Genes (HSK), such as ACT1, RDN18 or PDA1 are among the most commonly used, as their expression is assumed to remain unchanged over a wide range of conditions. Since this assumption is very unlikely, a geometric averaging of multiple, carefully selected internal control genes is now strongly recommended for normalization to avoid this problem of expression variation of single reference genes. The aim of this work was to search for a set of reference genes for reliable gene expression analysis in Saccharomyces cerevisiae.     

Evidence for a mitochondrial localization of the retinoblastoma protein

Background  

The retinoblastoma protein (Rb) plays a central role in the regulation of cell cycle, differentiation and apoptosis. In cancer cells, ablation of Rb function or its pathway is a consequence of genetic inactivation, viral oncoprotein binding or deregulated hyperphosphorylation. Some recent data suggest that Rb relocation could also account for the regulation of its tumor suppressor activity, as is the case for other tumor suppressor proteins, such as p53.     

Improvement in right ventricular function during reversibility testing in pulmonary arterial hypertension: a case report

Background

The percentage of hypertrophic cardiomyopathy (HCM) patients who are in high risk for Sudden Death (SD) constitutes only a minority of all HCM population but the incidence of SD in this subset is high (at least 5% annually). The identification of this small but important proportion of high risk HCM patients has been the clue in the clinical evaluation of these patients.

Methods

Our study cohort consisted from 123 patients with HCM who are currently followed up in our Institution. Five clinical risk factors were assessed: a family history of premature SD, unexplained syncope, Non Sustained Ventricular Tachycardia (NSVT) on 24-h ECG monitoring, Abnormal Blood Pressure Response (ABPR) during upright exercise testing and Maximum left ventricular Wall Thickness (MWT) ≥30 mm. The purpose of our study was the identification of high risk HCM patients coming from Northern Greece.

Results

Fifteen patients (12.2%) of the whole cohort had MWT ≥ 30 mm, 30 patients (24.4%) had an ABPR to exercise, 17 patients (13.8%) had episodes of NSVT in 24-h Holter monitoring, 17 patients (13.8%) suffered from syncope, and 8 patients (6.5%) had a positive family history of premature SD. Data analysis revealed that 74 patients (60.1%) had none risk factor. Twenty four patients (19.5%) had 1 risk factor, 17 patients (13.8%) had 2 risk factors, 4 patients (3.25%) had 3 risk factors, and 4 patients (3.25%) had 4 risk factors, while none patient had 5 risk factors. Twenty five patients (20.3%) had 2 or more risk factors.

Conclusion

This study for the first time confirms that, although a 60% of patients with HCM coming from a regional Greek population are in low risk for SD, a substantial proportion (almost 20%) carries a high risk for SD justifying prophylactic therapy with amiodaron or ICD implantation.     

A lipoxygenase with dual positional specificity is expressed in olives (Olea europaea L.) during ripening

Plant lipoxygenases (LOXs) are a class of widespread dioxygenases catalysing the hydroperoxidation of polyunsaturated fatty acids. Although multiple isoforms of LOX have been detected in a wide range of plants, their physiological roles remain to be clarified. With the aim to clarify the occurrence of LOXs in olives and their contribution to the elaboration of the olive oil aroma, we cloned and characterized the first cDNA of the LOX isoform which is expressed during olive development. The open reading frame encodes a polypeptide of 864 amino acids. This olive LOX is a type-1 LOX which shows a high degree of identity at the peptide level towards hazelnut (77.3%), tobacco (76.3%) and almond (75.5%) LOXs. The recombinant enzyme shows a dual positional specificity, as it forms both 9- and 13-hydroperoxide of linoleic acid in a 2:1 ratio, and would be defined as 9/13-LOX. Although a LOX activity was detected throughout the olive development, the 9/13-LOX is mainly expressed at late developmental stages. Our data suggest that there are at least two Lox genes expressed in black olives, and that the 9/13-LOX is associated with the ripening and senescence processes. However, due to its dual positional specificity and its expression pattern, its contribution to the elaboration of the olive oil aroma might be considered.     

Optimization Models and the Structure of the Genetic Code

The codon assignment of the quasi-universal genetic code can be assumed to have resulted from the evolutionary pressures that prevailed when the code was still evolving. Here, we review studies of the structure of the genetic code based on optimization models. We also review studies that, from the structure of the code, attempt to derive aspects of the primordial circumstances in which the genetic code froze. Different rationales are summarized, compared with experimental data, discussed in the context of the transition from a RNA world to a DNA-protein world, and linked to the emergence of the last universal common ancestor.