Spatiotemporal variations in density and biomass of rocky reef fish in a biogeographic climatic transition zone: trends over 9 years,inside and outside the only nearshore no-take marine-protected area on the southern Brazilian coast

Biogeographical transition zones are important areas to investigate evolutionary ecological questions, but long-term population monitoring is needed to better understand ecological processes that govern population variations in such edge environments. The southernmost Brazilian rocky reefs are the southern limit of distribution for 96% of the tropical ichthyofauna of the western Atlantic. The Arvoredo Marine Biological Reserve is the only nearshore no-take marine-protected area (MPA) located in this transition zone. The main aim was to investigate how the populations of rocky reef fish species vary in density and biomass in space and over time, inside and outside the Arvoredo MPA. This study presents results based on a 9 year (2008–2017) underwater visual census monitoring study to evaluate the density and biomass of key fish species. Variations in density and biomass were detected for most species. Factors and mechanisms that may have influenced spatial variation are habitat structural complexity and protection from fisheries. Temporal variations, otherwise, may have been influenced by species proximity to their distributional limit, in synergy with density-dependent mechanisms and stochastic winter temperature oscillations. The MPAs harbour higher density and biomass for most species. Nonetheless, a prominent temporal decline in the recruitment of Epinephelus marginatus calls into question the continuous effectiveness of the MPA.     

Applying a multiobjective metaheuristic inspired by honey bees to phylogenetic inference

The development of increasingly popular multiobjective metaheuristics has allowed bioinformaticians to deal with optimization problems in computational biology where multiple objective functions must be taken into account. One of the most relevant research topics that can benefit from these techniques is phylogenetic inference. Throughout the years, different researchers have proposed their own view about the reconstruction of ancestral evolutionary relationships among species. As a result, biologists often report different phylogenetic trees from a same dataset when considering distinct optimality principles. In this work, we detail a multiobjective swarm intelligence approach based on the novel Artificial Bee Colony algorithm for inferring phylogenies. The aim of this paper is to propose a complementary view of phylogenetics according to the maximum parsimony and maximum likelihood criteria, in order to generate a set of phylogenetic trees that represent a compromise between these principles. Experimental results on a variety of nucleotide data sets and statistical studies highlight the relevance of the proposal with regard to other multiobjective algorithms and state-of-the-art biological methods.     

A CRYGC gene mutation associated with autosomal dominant pulverulent cataract

Purpose

To describe at molecular level a family with pulverulent congenital cataract associated with a CRYGC gene mutation.

Methods

One family with several affected members with pulverulent congenital cataract and 230 healthy controls were examined. Genomic DNA from leukocytes was isolated to analyze the CRYGA-D cluster, CX46, CX50 and MIP genes through high-resolution melting curve and DNA sequencing.

Results

DNA sequencing in the affected members revealed the c.143G>A mutation (p.R48H) in exon 2 of the CRYGC gene; 230 healthy controls and ten healthy relatives were also analyzed and none of them showed the c.143G>A mutation. No other polymorphisms or mutations were found to be present.

Conclusion

In the present study, we described a family with pulverulent congenital cataract that segregated the c.143G>A mutation (p.R48H) in the CRYGC gene. A few mutations have been described in the CRYGC gene in autosomal dominant cataract, none of them with pulverulent cataract making clear the clinical heterogeneity of congenital cataract. This mutation has been associated with the phenotype of congenital cataract but also is considered an SNP in the NCBI data base. Our data and previous report suggest that p.R48H could be a disease-causing mutation and not an SNP.     

Myotonic dystrophytype 1 – report of non-24-h sleep-wake disorder with excessive daytime sleepiness

ABSTRACT

Myotonic dystrophy (MD) is a neuromuscular disease with myotonia, progressive weakness, and involvement of CNS, heart, and gastrointestinal system. Excessive daytime sleepiness (EDS) in myotonic dystrophy type 1 (MD1) is related to sleep breathing diseases, restless leg syndrome, periodic limb movements during sleep and narcoleptic-like phenotype. However, authors highlight a central dysfunction of sleep regulation.

We describe a 26-year-old, female, MD1 patient with EDS. Sleep diary/actigraphy evidenced two different circadian periods with values of 1442 and 1522 min. Agomelatine, 50 mg at night, was prescribed with improvement of the circadian rhythm and complaints of sleepiness.

The identification of unanticipated causes of EDS, such as circadian rhythm disorders permits an appropriated treatment. As we know, it is the first relate of non-24-h sleep-wake disorder in patient with MD1. Sleep diary and actigraphy could be good options to investigate sleep-wake cycle disorder in patients with MD and EDS.     

Immunogenic properties of a lettuce-derived C4(V3)6 multiepitopic HIV protein

Elicitation of broad humoral immune responses is a critical factor in the development of effective HIV vaccines. In an effort to develop low-cost candidate vaccines based on multiepitopic recombinant proteins, this study has been undertaken to assess and characterize the immunogenic properties of a lettuce-derived C4(V3)6 multiepitopic protein. This protein consists of V3 loops corresponding to five different HIV isolates, including MN, IIIB, RF, CC, and RU. In this study, both Escherichia coli and lettuce-derived C4(V3)6 have elicited local and systemic immune responses when orally administered to BALB/c mice. More importantly, lettuce-derived C4(V3)6 has shown a higher immunogenic potential than that of E. coli-derived C4(V3)6. Moreover, when reactivity of sera from mice immunized with C4(V3)6 are compared with those elicited by a chimeric protein carrying a single V3 sequence, broader responses have been observed. The lettuce-derived C4(V3)6 has elicited antibodies with positive reactivity against V3 loops from isolates MN, RF, and CC. In addition, splenocyte proliferation assays indicate that significant T-helper responses are induced by the C4(V3)6 immunogen. Taken together, these findings account for the observed elicitation of broader humoral responses by the C4(V3)6 multiepitopic protein. Moreover, they provide further validation for the production of multiepitopic vaccines in plant cells as this serves not only as a low-cost expression system, but also as an effective delivery vehicle for orally administered immunogens.     

Electrical hypothesis of toxicity of the Cry toxins for mosquito larvae

Many electrical properties of insect larval guts have been studied, but their importance for toxicity of the Cry-type toxins has never been reported in the literature. In the present work, we observed potential-dependent permeabilization of plasma membrane by several polycationic peptides derived from the Cry11Bb protoxin. The peptide BTM-P1d, all D-type amino acid analogue of the earlier reported peptide BTM-P1, demonstrated high membrane-permeabilizing activity in experiments with isolated rat liver mitochondria, RBC (red blood cells) and mitochondria in homogenates of Aedes aegypti larval guts. Two larger peptides, BTM-P2 and BTM-P3, as well as the Cry11Bb protoxin treated with the protease extract of mosquito larval guts showed similar effects. Only protease-resistant BTM-P1d, in comparison with other peptides, displayed A. aegypti larval toxicity. Taking into account the potential-dependent mechanism of membrane permeabilization by studied fragments of the Cry11Bb protoxin and the literature data related to the distribution of membrane and transepithelial potentials in the A. aegypti larval midgut, we suggest an electrical hypothesis of toxicity of the Cry toxins for mosquito larvae. According to this hypothesis, the electrical field distribution is one of the factors determining the midgut region most susceptible for insertion of activated toxins into the plasma membrane to form pores. In addition, potential-dependent penetration of short active toxin fragments into the epithelial cells could induce permeabilization of mitochondria and subsequent apoptosis or necrosis.     

Effects of coypu (Myocastor coypus) abundances and diet selection on a wetland of the Patagonian steppe

We assessed diet selection, impact on vegetation, and explored habitat relationships with marsh birds of coypus (Myocastor coypus) in a steppe lagoon in Argentinean Patagonia. In two consecutive springs, abundance and spatial use of the coypus and nesting marsh birds were estimated by direct counts. The coypu was a selective consumer with seasonal variations in food items, and Myriophyllum sp. and Schoenoplectus californicus dominated its diet. Coypus and marsh birds showed a differential spatial use when rushes cover was high. However, when rushes cover decreased by coypu browsing, there was a similar use of space, and marsh birds were displaced to nest on the open water and other poorly protected areas of the rushes. Our results suggest that high abundances of coypu can have a detrimental effect on wetland ecosystems. Systematic monitoring and evaluation of their effects on wetlands in recently colonized areas is recommended.     

Deregulation of excitatory neurotransmission underlying synapse failure in Alzheimer's disease

Alzheimer′s disease (AD) is the most common form of dementia in the elderly. Memory loss in AD is increasingly attributed to soluble oligomers of the amyloid‐β peptide (AβOs), toxins that accumulate in AD brains and target particular synapses. Glutamate receptors appear to be centrally involved in synaptic targeting by AβOs. Once bound to neurons, AβOs dysregulate the activity and reduce the surface expression of both N‐methyl‐d ‐aspartate (NMDA) and 2‐amino‐3‐(3‐hydroxy‐5‐methyl‐isoxazol‐4‐yl)propanoic acid (AMPA) types of glutamate receptors, impairing signaling pathways involved in synaptic plasticity. In the extracellular milieu, AβOs promote accumulation of the excitatory amino acids, glutamate and d ‐serine. This leads to overactivation of glutamate receptors, triggering abnormal calcium signals with noxious impacts on neurons. Here, we review key findings linking AβOs to deregulated glutamate neurotransmission and implicating this as a primary mechanism of synapse failure in AD. We also discuss strategies to counteract the impact of AβOs on excitatory neurotransmission. In particular, we review evidence showing that inducing neuronal hyperpolarization via activation of inhibitory GABA_A receptors prevents AβO‐induced excitotoxicity, suggesting that this could comprise a possible therapeutic approach in AD.