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The morphology of an individual can improve its ability to escape predators and ultimately its chances of survival. Sicydiine fishes reproduce in rivers, and their larvae develop in the sea. Once juveniles arrive in rivers, they face numerous predatory fish species. Some juveniles can climb above the first waterfall where the abundance of predatory species is reduced. For individuals that do not climb waterfalls, survival only depends upon their ability to avoid predation. While the factors that affect climbing performance of sicydiines have been extensively described, the information is scarce concerning their predator escape performance. Our experimental study aimed to describe how the predation pressure imposed by three predatory fish species (Eleotris klunzingerii, Kuhlia rupestris, and Anguilla marmorata) affects the individual morphology of juveniles of two sicydiine species from Reunion Island (Cotylopus acutipinnis and Sicyopterus lagocephalus). Individuals which survived predation had a more streamlined body and larger and/or longer pectoral fins for the two sicydiine species, whereas others morphological variables differed with the predator species. Body form of individuals that survived predation also differed from the body form of individuals that climbed waterfalls. The different prey's body forms under selection by the three predator species should be considered in further studies that could address the tradeoff in sicydiines between climbing waterfalls and escaping predation in the field. For example, a careful description of the predator community would help to understand which predator(s) sicydiines juveniles need to escape in downstream reaches and how this particular predation pressure can select body forms. [ABSTRACT FROM AUTHOR]

Conventional methods for surveying diadromous fish migration from marine coastal waters to freshwater habitats are mainly based on electrofishing, a non-optimal technique for the study of fish migrations in rivers, and fishermen catch data. Underwater video has been recognized for a long time as a good alternative, but those approaches usually require intensive labour for retrieving the information from the video sequences. To overcome these problems, an underwater video system specifically designed for field work (low-weight, low-cost and autonomous) named BichiCAM has been developed for automatically counting, measuring and tracking fish observed in video sequences. The efficiency and precision of the BichiCAM system were tested by filming Sicyopterus lagocephalus juveniles passing through the camera field of vision in the Saint-Etienne River, Reunion Island, Western Indian Ocean. The BichiCAM system accurately measured fish length of the observed individuals when lens distortion of the camera was corrected, and the error percentages on the measurements presented a standard deviation of 5.1% of the total length. The BichiCAM system provides a powerful tool that will not only facilitate research on migrating fishes and invertebrates' communities but also allow studies of the effectiveness of fishways associated to dams or the impacts of fishery activities. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The functional capacities of animals are a primary factor determining survival in nature. In this context, understanding the biomechanical performance of animals can provide insight into diverse aspects of their biology, ranging from ecological distributions across habitat gradients to the evolutionary diversification of lineages. To survive and reproduce in the face of environmental pressures, animals must perform a wide range of tasks, some of which entail tradeoffs between competing demands. Moreover, the demands encountered by animals can change through ontogeny as they grow, sexually mature or migrate across environmental gradients. To understand how mechanisms that underlie functional performance contribute to survival and diversification across challenging and variable habitats, we have pursued diverse studies of the comparative biomechanics of amphidromous goby fishes across functional requirements ranging from prey capture and fast-start swimming to adhesion and waterfall climbing. The pan-tropical distribution of these fishes has provided opportunities for repeated testing of evolutionary hypotheses. By synthesizing data from the lab and field, across approaches spanning high-speed kinematics, selection trials, suction pressure recordings, mechanical property testing, muscle fiber-type measurements and physical modeling of bioinspired designs, we have clarified how multiple axes of variation in biomechanical performance associate with the ecological and evolutionary diversity of these fishes. Our studies of how these fishes meet both common and extreme functional demands add new, complementary perspectives to frameworks developed from other systems, and illustrate how integrating knowledge of the mechanical underpinnings of diverse aspects of performance can give critical insights into ecological and evolutionary questions., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

The life cycle of gobies of the Sicydiinae subfamily depends on climbing waterfalls. Two sympatric sicydiines species from Reunion Island, Sicyopterus lagocephalus (SIL) and Cotylopus acutipinnis (COA), employ different climbing modes. SIL uses a steady "inching" mode interrupted by short rest periods, whereas COA exhibits short "power-burst" undulatory movements punctuated by longer rest periods. Consequently, we explored the relationship between climbing performance and metabolic activity in these two species. We demonstrated that the two climbing modes are supported by different ecophysiological profiles that promote the interspecific variability of locomotor performance. More specifically, SIL performed better than COA during a climbing experiment because of its inching climbing mode, supported by a generally greater metabolic capacity and a higher potential for oxidative metabolism. Interestingly, we did not detect any difference in metabolic fuel storage and lactate production during climbing in either species, suggesting that these species can maintain fuel reserves and limit lactate accumulation through extensive rest times. Overall, this study provides new insights into the ecophysiology of these two emblematic species and suggests that the better climbing capacity of SIL is supported by its muscular metabolic capacity.

Over the last few decades, plastic waste has become an increasing environmental concern as it accumulates in every environment on our planet. Though traditionally seen as a macroscopic problem (i.e., large plastic debris), plastic pollution is also evident at smaller scales. Indeed, the intentional industrial production of small plastic particles and the physical degradation of larger plastic debris have overtime resulted in an increased environmental prevalence of smaller plastic particles, including microplastics. While the effects of these small polymers on marine biota have been an important research focus, recent global surveys indicate that our freshwater lakes and rivers are also plagued by microplastics. However, despite these discoveries we currently have a limited understanding of the impact these particles may have on freshwater animals, particularly on vertebrate species. Thus, the aim of the present study was to assess the impact of high concentrations of microplastics (5 and 20 mg.L -1 ) on the early life stages in zebrafish, a model freshwater vertebrate model. To do this, we exposed embryonic and larval zebrafish to fluorescently labelled polyethylene microspheres for up to 14 days and assessed their microplastic content, growth, hatching and oxygen consumption rates. We then explored the molecular underpinnings of the microplastic response by RNA sequencing. Over the course of the exposure, we observed a consistent accumulation of microplastics in the gastrointestinal tract of the fish in a concentration dependent manner, but could not detect any detrimental effects of these particles on larval development, growth or metabolism. However, whole animal transcriptomics revealed that microplastics induced a transient and extensive change in larval gene expression within 48 h exposure, which largely disappeared by 14 days. However, as these transcriptional changes occurred during a critical period of larval development, we suggest that an evaluation of the potential long-term impact of these particles is warranted., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We report the first observation of subcutaneous phycomycosis with isolation of the strain in Central African Republic and the efficiency of fluconazole therapy.

A variant of metachromatic leukodystrophy (MLD), Austin disease, is characterized by a multiple isozyme deficiency of arylsulfatase. A 3 1/2-year-old girl with progressive mental and physical deterioration had decreased activities of arylsulfatases A and B in the leukocytes, shown by acylamide gel electrophoresis. Under the electron microscope, biopsy specimens of the brain and the peripheral nerve showed lamellar structures with socalled zebra bodies in the cytoplasmic processes of glial cells, granulo-membranous inclusions with fingerprint configurations in neurons, and myelinlike material in Schwann cells. Results from our study suggest an intricate nature of this dysmetabolic disorder, which shows ultrastructural changes usually seen in classic MLD, a deficiency of arylsulfatase A only, concomitant with those seen in mucopolysaccharidoses such as Hurler and Sanfilippo syndromes.

In order to determine the proportion of tuberculosis (TB) patients in Bangui (Central African Republic) infected with human immunodeficiency virus (HIV), we collected prospectively serum samples from all new TB patients seen at the University Hospital in Bangui during a three-month period (nov. 87-Jan. 88). 220 serum samples were tested for antibodies to HIV, by an Elisa assay and confirmed by Western-Blot. The general HIV seropositivity rate among TB patients was 27.7% (31.2% in adults (N = 183), and 10.8% in children (N = 37)). Within the adult population, there was non association between HIV infection and sex or previous history of TB. Seropositivity was more common in patients with extrapulmonary TB, especially lymphadenitis, and in patients with mediastinal adenopathy, or extensive pulmonary involvement without cavitation. Seropositivity was also strongly associated with negative tuberculin skin tests, chronic diarrhoea, generalized lymphadenopathy, and thrush. It is concluded that HIV infection is responsible for the increasing incidence of tuberculosis in Central African Republic, and that investigations for TB should be carried out in every symptomatic African patient infected with HIV.