Global variation in freshwater physico-chemistry and its influence on chemical toxicity in aquatic wildlife

Chemical pollution is one of the major threats to global freshwater biodiversity and will be exacerbated through changes in temperature and rainfall patterns, acid–base chemistry, and reduced freshwater availability due to climate change. In this review we show how physico-chemical features of natural fresh waters, including pH, temperature, oxygen, carbon dioxide, divalent cations, anions, carbonate alkalinity, salinity and dissolved organic matter, can affect the environmental risk to aquatic wildlife of pollutant chemicals. We evidence how these features of freshwater physico-chemistry directly and/or indirectly affect the solubility, speciation, bioavailability and uptake of chemicals [including via alterations in the trans-epithelial electric potential (TEP) across the gills or skin] as well as the internal physiology/biochemistry of the organisms, and hence ultimately toxicity. We also show how toxicity can vary with species and ontogeny. We use a new database of global freshwater chemistry (GLORICH) to demonstrate the huge variability (often >1000-fold) for these physico-chemical variables in natural fresh waters, and hence their importance to ecotoxicology. We emphasise that a better understanding of chemical toxicity and more accurate environmental risk assessment requires greater consideration of the natural water physico-chemistry in which the organisms we seek to protect live.     

A new species of the ghost shrimp genus Neocallichirus Sakai, 1988 (Decapoda: Axiidea: Callianassidae) from the southwestern Atlantic

ABSTRACT

A new species of ghost shrimp, Neocallichirus pinheiroi, is described based on specimens collected in subtidal habitats of Saquaira beach, northeastern coast of Brazil. This new species resembles N. lemaitrei Manning, 1993, but differs from it primarily in having a third maxilliped propodus expanded ventrally, and in the case of males, a large subtriangular tooth on the cutting edge of the major cheliped dactylus. Diagnostic features of the new species include: (i) frontal margin of carapace with rounded lateral projections not exceeding rostrum distal margin, (ii) third maxilliped carpus with row of sclerotized setae on median internal surface, (iii) minor cheliped with cutting edge of dactylus microscopically pectinate, (iv) endopod of male second pleopod with appendices interna and masculina. This is the seventh described species of the genus Neocallichirus from the western Atlantic and the fourth report of this genus in Brazil. A key for identification of western Atlantic species belonging to the genus is provided.     

Urinary Hydroxyproline in the Elderly with Low Leucocyte Ascorbic Acid Levels

Fourteen elderly patients aged 58 to 91 with varying leucocyte ascorbic acid levels had urinary hydroxyproline/creatinine ratios measured before, during, and after treatment with ascorbic acid 1 g. daily for six days. The ratio increased during treatment in those patients whose initial ascorbic acid levels were below 15μg./10⁸ white blood cells. It is suggested that collagen metabolism may be impaired in these patients, and that all such patients should receive ascorbic acid supplements.     

Brachygnathia,cardiomegaly and renal hypoplasia syndrome (BCRHS) in Merino sheep maps to a 1.1‐megabase region on ovine chromosome OAR2

A genome scan was conducted to map the autosomal recessive lethal disorder brachygnathia, cardiomegaly and renal hypoplasia syndrome (BCRHS) in Poll Merino sheep. The scan involved 10 affected and 27 unaffected animals from a single Poll Merino/Merino sheep flock, which were genotyped with the Illumina Ovine SNP50 BeadChip. Association and homozygosity mapping analyses located the disorder in a region comprising 20 consecutive SNPs spanning 1.1 Mb towards the distal end of chromosome OAR2. All affected animals and none of the unaffected animals were homozygous for the associated haplotype in this region. These results provide the basis for identifying the causative mutation(s) and should enable the development of a DNA test to identify carriers in the Poll Merino sheep population. Understanding the molecular control of BCRHS may provide insight into the fundamental genetic control and regulation of the affected organ systems.     

Detection of Wolbachia Bacteria in Multiple Organs and Feces of the Triatomine Insect Rhodnius pallescens (Hemiptera, Reduviidae)

At least two types of Wolbachia bacteria were detected in wild and insectarium-raised Rhodnius pallescens, a natural vector of Trypanosoma cruzi and Trypanosoma rangeli. Wolbachia was detected in all the organs and tissues studied and in the feces, and this provided a methodological advantage for determining the presence of this endosymbiont in this host, obviating the need to kill the specimens. The occurrence of trypanosomatids in wild individuals was also studied.