The relationships between brain,serum, and whole blood ChE activity in the wood mouse (Apodemus sylvaticus) and the common shrew (Sorex araneus) after acute sublethal exposure to dimethoate

Abstract

Inhibition of cholinesterase (ChE) activity produced by a single acute intraperitoneal administration of dimethoate was studied in the wood mouse, Apodemus sylvaticus, and the common shrew, Sorex araneus, under laboratory conditions. ChE values from serum and whole blood were compared with those obtained from brain in order to obtain a non-destructive tool for predicting the severity of brain acetylcholinesterase (AChE) inhibition. In addition, serum and brain inhibition following oral exposure to dimethoate was also measured in the wood mouse. Normal ChE activity was higher in the brain and whole blood of the shrews than in wood mice. There was no difference between species in serum ChE activity. Exposure to dimethoate caused a dose-dependent reduction in ChE activity and there was a significant recovery in activity with increasing time after administration. In both species, serum and whole blood were more sensitive than brain for revealing organophosphate-induced ChE inhibition and serum was more sensitive than whole blood. Statistically significant relationships were defined between whole blood and brain ChE activity and between serum and brain ChE activity. Compared with serum, whole blood ChE activity was the more accurate predictor of brain AChE levels. The relationships between brain and serum ChE activity did not appear to be affected by the route of administration of the pesticide.     

Corvids avoid odd evaluation by following simple rules in a risky exchange task

In their natural environment, animals often make decisions crucial for survival, such as choosing the best patch or food, or the best partner to cooperate. The choice can be compared to a gamble with an outcome that is predictable but not certain, such as rolling a dice. In economics, such a situation is called a risky context. Several models show that although individuals can generally evaluate the odds of each potential outcome, they can be subject to errors of judgment or choose according to decision-making heuristics (simple decision rules). In non-human primates, similar errors of judgment have been reported and we have recently shown that they also use a decisional heuristics when confronted with a risky choice in an exchange task. This suggests a common evolutionary origin to the mechanisms underlying decision-making under risk in primates. However, whether the same mechanisms are also present in more distantly related taxa needs to be further investigated. Other social species, like corvids, are renowned for their advanced cognitive skills and may show similar responses. Here, we analyse data on corvids (carrion crows, hooded crows, common ravens and rooks) tested in a risky exchange task comparable to the one used in non-human primates. We investigated whether corvids could exchange according to the odds of success or, alternatively, whether they used a heuristic similar to the one used by non-human primates. Instead, most corvids chose a course of action (either a low or high exchange rate) that remained constant throughout the study. In general, corvids’ mean exchange rates were lower compared to non-human primates, indicating that they were either risk-adverse or that they do not possess the cognitive capabilities to evaluate odds. Further studies are required to evaluate the flexibility in exchange abilities of these birds in exchange abilities of these birds.     

Predicting the factors influencing the inter- and intraspecific survival rates of riverine fishes implanted with acoustic transmitters

Biotelemetry is a central tool for fisheries management, with the implantation of transmitters into animals requiring refined surgical techniques that maximize retention rates and fish welfare. Even following successful surgery, long-term post-release survival rates can vary considerably, although knowledge is limited for many species. The aim here was to investigate the post-tagging survival rates in the wild of two lowland river fish species, common bream Abramis brama and northern pike Esox lucius, following their intra-peritoneal double-tagging with acoustic transmitters and passive integrated transponder (PIT) tags. Survival over a 2-year period was assessed using acoustic transmitter data in Cox proportional hazards models. Post-tagging survival rates were lowest in the reproductive periods of both species, but in bream, fish tagged just prior to spawning actually had the highest subsequent survival rates. Pike survival was influenced by sex, with males generally surviving longer than females. PIT tag detections at fixed stations identified bream that remained active, despite loss of an acoustic transmitter signal. In these instances, loss of the acoustic signal occurred up to 215 days post-tagging and only during late spring or summer, indicating a role of elevated temperature, while PIT detections occurred between 18 and 359 days after the final acoustic detections. Biotelemetry studies must thus always consider the date of tagging as a fundamental component of study designs to avoid tagged fish having premature end points within telemetry studies.     

Physical maturity in common bottlenose dolphins (Tursiops truncatus) from Sarasota Bay,Florida

Cetacean physical maturity is defined by growth cessation and complete fusion of epiphyses to vertebral bodies indicated by invisible sutures. Many studies have shown epiphyseal fusion is highly variable among individuals. In-depth examinations into fusion variability are lacking. We analyzed vertebrae of 37 (n = 21 female, n = 16 male) stranded common bottlenose dolphins (Tursiops truncatus) from the well-studied Gulf of Mexico, Sarasota Bay community. For each specimen, vertebrae were examined by vertebral region for degree of fusion anteriorly and posteriorly of each centrum and categorized from unfused to fused in five degrees. An ordinal logistic regression was used to estimate degree of fusion probability for each epiphysis. The model had fixed effects for age, number of offspring, sex, sexual maturity, and a random effect for epiphysis. Results show that age/reproductive status significantly explains an individual's degree of fusion. Adult females with fewer calves had more fusion than those with more reproductive experience across multiple ages. Access to long-term observational and sample data on the dolphins residing in the area served by Mote Marine Laboratory's Stranding Investigations Program offers a unique opportunity to examine the relationship between energetic demands of reproduction (calcium production/reproductive output) versus preconceived definitions of physical maturity (skeletal fusion) more closely.     

Adverse responses of Cabera pusaria caterpillars to high dietary manganese concentration

The adaptation of insects to environmental changes can constitute a crucial factor in their development and activity. The response of Cabera pusaria L. (Lepidoptera: Geometridae) caterpillars to high manganese (Mn) concentrations in the diet was studied. Birch leaves were treated by dipping in MnCl₂·4H₂O solutions, thereby achieving Mn contents of 370 (T0), 695 (T1), 3 198 (T2), and 6 302 mg kg⁻¹ (T3). The reactions were determined by observing caterpillar mortality, development time, food consumption, and pupal weight. Manganese concentrations in larval excrement, pupae, and food were determined. Manganese in the diet at unnaturally increased concentrations caused great stress for caterpillars. All individuals in the treatment with the highest Mn concentration (T3) died during rearing and successful pupation occurred in only four individuals in T2. Even in the case of caterpillars from T1 (twofold higher than T0) a negative reaction (increased food consumption and prolonged development) was recorded. We also determined significantly increased Mn concentration in pupae from T1 (T2 and T3 were not included in this evaluation due to mortality) and excrement (T1‒T3) compared with T0 having a natural Mn concentration. Caterpillars were seen to eliminate negatively acting dietary Mn by its translocation to excrement. However, the highest mortality rate in T2 and T3 and negative reactions of individuals in T1 very likely demonstrate energy insufficiency and the high energy requirements of Mn elimination mechanisms.     

Biological control of Meloidogyne incognita and Fusarium solani in dry common bean in the field

Meloidoyne incognita (root-knot nematode) and Fusarium solani (root-rot pathogen) were the common soil-borne pathogens and cause severe damage to bean plants in newly reclaimed sandy soil in Nubaryia district, Behera Governorate, Egypt. The antagonistic effects of Trichoderma album and Trichoderma viride as well as three commercial products namely Rhizo-N^® (Bacillus subtilis), Bio-Arc^® 6% (Bacillus megaterium) and Bio-Zeid^® 2.5% (T. album) were tested against M. incognita and F. solani under naturally infected field conditions. T. album and T. viride highly reduced the frequency (%) population of pathogenic fungi such as Fusarium spp., F. solani and Rhizoctonia spp., than the commercial products. Results indicated that all the tested bio-control agents reduced, significantly, the nematode criteria as evidenced by the number of juvenile (J₂) in soil and number of galls and egg masses on roots of common bean and Fusarium root-rot incidence (%). Rhizo-N^® highly reduced the number of J₂ in soil, while T. album was the best in reducing the number of galls and egg masses in roots. The bio-control agents also increased the plant growth parameters of common bean plants i.e. plant height, plant weight, branch no./plant, pods no./plant, pod weight/plant, pod weight, seeds no./plant, fresh seeds weight/pod, dry seeds weight/pod and dry weight of 100 seeds.     

Far‐eastern strains of bean common mosaic virus and methods of their immunodiagnostics

The paper presents data of investigation on the physico‐chemical and antigenic properties of capsid proteins of the Bean common mosaic virus isolated from Phaseolus plants in the Russian Far East (BCMV‐R) and from China (BCMV‐C). A method for isolation of the virus preparation was selected. The purified preparations of two isolates BCMV have been obtained. The presence of one polypeptide in structural proteins of virions was established and their molecular masses determined (BCMV‐R ‐ 31,6 kD; BCMV‐C ‐ 32,1 kD). Polyclonal antiserum was obtained with titre 1:12800 and the indirect and “sandwich"‐variants of ELISA were developed to detect this virus. The allied relationships were established with the bean yellow mosaic virus and with the type representative of the genus Potyvirus ‐ PVY. Based on the data of physico‐chemical and antigenic properties it was concluded that isolates BCMV‐R and BCMV‐C are two independent strains of this virus. The presence of strain‐, virus‐ and genusspecific epitopes of capsid proteine was revealed as a result of comparison of antigenic characteristics of the Russian Far Eastern and Chinese strains of BCMV. A high antigenic activity of capsid protein of the Russian Far Eastern strain was observed.     

Distribution and impact of virus associated diseases of common bean (Phaseolus vulgaris L.) in northern Iran

Different viral diseases infect common bean crops in Iran. A total of 248 symptomatic samples were collected from common bean fields throughout main growing fields of Guilan province in Iran during the summer of 2006. Eight viruses were detected using double antibody-sandwich – enzyme-linked immunosorbent assay (DAS-ELISA). Bean common mosaic virus – BCMV (1%), Bean leaf roll virus – BLRV (9%), Cowpea mild mottle virus – CpMMV (6%), Southern bean mosaic virus – SBMV (3%), Cucumber mosaic virus – CMV (15%), Bean golden mosaic virus – BGMV (2%), Bean common mosaic necrosis virus – BCMNV (1%) and Bean yellow mosaic virus – BYMV (1%) were detected. Comparatively CMV (15%) was found to be more prevalent in Guilan province. Multiple infections of viruses were recorded in many samples. Weed species belonging to Chenopodiaceae, Solanaceae, Malvaceae and Amaranthaceae families were also found to be infected with the viruses.     

Evolution of the salivary apyrases of blood-feeding arthropods

Phylogenetic analyses of three families of arthropod apyrases were used to reconstruct the evolutionary relationships of salivary-expressed apyrases, which have an anti-coagulant function in blood-feeding arthropods. Members of the 5′nucleotidase family were recruited for salivary expression in blood-feeding species at least five separate times in the history of arthropods, while members of the Cimex-type apyrase family have been recruited at least twice. In spite of these independent events of recruitment for salivary function, neither of these families showed evidence of convergent amino acid sequence evolution in salivary-expressed members. On the contrary, in the 5′-nucleotide family, salivary-expressed proteins conserved ancestral amino acid residues to a significantly greater extent than related proteins without salivary function, implying parallel evolution by conservation of ancestral characters. This unusual pattern of sequence evolution suggests the hypothesis that purifying selection favoring conservation of ancestral residues is particularly strong in salivary-expressed members of the 5′-nucleotidase family of arthropods because of constraints arising from expression within the vertebrate host.     

Hemocyanin gene family evolution in spiders (Araneae), with implications for phylogenetic relationships and divergence times in the infraorder Mygalomorphae

Hemocyanins are multimeric copper-containing hemolymph proteins involved in oxygen binding and transport in all major arthropod lineages. Most arachnids have seven primary subunits (encoded by paralogous genes a–g), which combine to form a 24-mer (4 × 6) quaternary structure. Within some spider lineages, however, hemocyanin evolution has been a dynamic process with extensive paralog duplication and loss. We have obtained hemocyanin gene sequences from numerous representatives of the spider infraorders Mygalomorphae and Araneomorphae in order to infer the evolution of the hemocyanin gene family and estimate spider relationships using these conserved loci. Our hemocyanin gene tree is largely consistent with the previous hypotheses of paralog relationships based on immunological studies, but reveals some discrepancies in which paralog types have been lost or duplicated in specific spider lineages. Analyses of concatenated hemocyanin sequences resolved deep nodes in the spider phylogeny and recovered a number of clades that are supported by other molecular studies, particularly for mygalomorph taxa. The concatenated data set is also used to estimate dates of higher-level spider divergences and suggests that the diversification of extant mygalomorphs preceded that of extant araneomorphs. Spiders are diverse in behavior and respiratory morphology, and our results are beneficial for comparative analyses of spider respiration. Lastly, the conserved hemocyanin sequences allow for the inference of spider relationships and ancient divergence dates.