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Clarias gariepinus collected from Lake Heritage, Crocodile River, were found to harbour camallanid nematodes. Previously, Boomker (1982) surveyed the Hartbeespoort Dam, downstream of the current study site, and identified a high prevalence of Procamallanus (Procamallanus) laeviconchus and Paracamallanus cyathopharynx. Since then, Procamallanus (Procamallanus) pseudolaeviconchus was described from C. gariepinus suggesting reconsideration of the identifications of Procamallanus species in historical studies from clariids. The aim of the current study was to definitively identify the nematodes collected from C. gariepinus in Lake Heritage, using morphological and molecular analyses. Morphological study consisted of light and scanning electron microscopy which confirmed the identity P. (P.) pseudolaeviconchus and P. cyathopharynx. This included descriptions of the detailed morphology of isolated buccal capsules for both species using soft tissue digestion, notably for the first time for P. (P.) pseudolaeviconchus. The morphology of isolated spiculae of both species was described for the first time using SEM. Molecular analyses included genetic characterisation of the small ribosomal subunit (18S) rDNA and cytochrome oxidase 1 (CO1) mtDNA. Genetic data supported the morphological identification of both species, however, divergence was detected in CO1 mtDNA data for P. cyathopharynx indicating two distinct lineages. Due to this variation, the morphometry of P. cyathopharynx specimens were revisited including statistical re-evaluation. No robust morphological traits were identified to support CO1 mtDNA lineages and all specimens were considered conspecific. In terms of camallanid biodiversity in the Crocodile River system, it is similar to that in Boomker (1982), despite the altered water quality from past acid mine pollution in the river.

A field experiment (N = 4,536) examined how signs of social class influence compassionate responses to those in need. Pedestrians in two major cities in the United States were exposed to a confederate wearing symbols of relatively high or low social class who was requesting money to help the homeless. Compassionate responding was assessed by measuring the donation amount of the pedestrians walking past the target. Pedestrians gave more than twice (2.55 times) as much money to the confederate wearing higher-class symbols than they did to the one wearing lower-class symbols. A follow-up study (N = 504) exposed participants to images of the target wearing the same higher- or lower-class symbols and examined the antecedents of compassionate responding. Consistent with theorizing, higher-class symbols elicited perceptions of elevated competence, trustworthiness, similarity to the self, and perceived humanity compared to lower-class symbols. These results indicate that visible signs of social class influence judgments of others’ traits and attributes, as well as in decisions to respond compassionately to the needs of those who are suffering.

Carotenoids have been shown to be essential for human nutrition. Consumption of carotenoid-rich fruits and vegetables can reduce the risk of many diseases. The ketocarotenoid astaxanthin has become a commercially valuable compound due to its powerful antioxidant properties compared to other carotenoids. It is naturally produced in certain algae, bacteria, and the flowers of some species of the genus Adonis, although it is produced in such small quantities in these organisms that it is costly to extract. Chemical synthesis of this compound has also shown limited success with a high proportion of esterified forms of astaxanthin being produced, which decreases antioxidant properties by the conversion of hydroxyl groups to esters. Previously, transgenic astaxanthin-producing plants have been created using a β-carotene ketolase enzyme of either bacterial or algal origin. However, a novel astaxanthin pathway exists in the flowering plants of the genus Adonis which has not been utilized in the same manner. The pathway involves two unique enzymes, β-ring-4-dehydrogenase and 4-hydroxy-β-ring-4-dehydrogenase, which add the necessary hydroxyl and ketone groups to the rings of β-carotene. In the present study, Nicotiana benthamiana plants were transformed with chimeric constructs coding for these two enzymes. The regenerated, transgenic plants accumulate astaxanthin and their growth (height and weight) was unaffected, when compared to non-transformed N. benthamiana and to plants transformed with the bacterial β-carotene ketolase. The accumulation of astaxanthin also improved seedling survivability under harsh UV light, mitigated reactive oxygen accumulation, and provided a phenotype (color) that allowed the efficient identification and recovery of transgenic plants with and without selection.

Sleep is critical for memory consolidation, although the exact mechanisms mediating this process are unknown. Combining reduced network models and analysis of in vivo recordings, we tested the hypothesis that neuromodulatory changes in acetylcholine (ACh) levels during non-rapid eye movement (NREM) sleep mediate stabilization of network-wide firing patterns, with temporal order of neurons' firing dependent on their mean firing rate during wake. In both reduced models and in vivo recordings from mouse hippocampus, we find that the relative order of firing among neurons during NREM sleep reflects their relative firing rates during prior wake. Our modeling results show that this remapping of wake-associated, firing frequency-based representations is based on NREM-associated changes in neuronal excitability mediated by ACh-gated potassium current. We also show that learning-dependent reordering of sequential firing during NREM sleep, together with spike timing-dependent plasticity (STDP), reconfigures neuronal firing rates across the network. This rescaling of firing rates has been reported in multiple brain circuits across periods of sleep. Our model and experimental data both suggest that this effect is amplified in neural circuits following learning. Together our data suggest that sleep may bias neural networks from firing rate-based towards phase-based information encoding to consolidate memories.

Neoergasilus japonicus, a fish ectoparasite indigenous to eastern and southern Asia, has been introduced to various regions, including Europe and North and South America, where it spreads at an alarming rate. The parasite is not host‐specific. It was also collected from the Vaal‐Orange and Limpopo river systems in South Africa. This report describes the morphology of the wound‐inflecting structures in N. japonicus and relates their morphology to the pathological effect on Tilapia sparrmanii. Host tissue with parasites attached was imbedded in resin for histological sectioning and stained with haematoxylin and eosin. Additional specimens were prepared for scanning electron microscopy. Adult female parasites attach by inserting the hooked tips of the antennae into the epidermis. The maxillulae are minute but have sharp tips. The maxillae have sharp tips on the endopod and brush‐like setae on the exopod. The mandibles are armed with sharp tips. These structures are used to remove the epidermis of the host and brush it into the buccal cavity. Host tissue in the intestine confirms that adult females consume host tissue leaving the dermis exposed to opportunistic diseases. The microscopic size of the parasite prevents casual observation, and its occurrence in Africa is, therefore, probably underreported. [ABSTRACT FROM AUTHOR]

We explore the possible role of network dynamics near a critical point in the storage of new information in silico and in vivo, and show that learning and memory may rely on neuronal network features mediated by the vicinity of criticality. Using a mean-field, attractor-based model, we show that new information can be consolidated into attractors through state-based learning in a dynamical regime associated with maximal susceptibility at the critical point. Then, we predict that the subsequent consolidation process results in a shift from critical to sub-critical dynamics to fully encapsulate the new information. We go on to corroborate these findings using analysis of rodent hippocampal CA1 activity during contextual fear memory (CFM) consolidation. We show that the dynamical state of the CA1 network is inherently poised near criticality, but the network also undergoes a shift towards sub-critical dynamics due to successful consolidation of the CFM. Based on these findings, we propose that dynamical features associated with criticality may be universally necessary for storing new memories.

Clarias gariepinus collected from Lake Heritage, Crocodile River, were found to harbour camallanid nematodes. Previously, Boomker (1982) surveyed the Hartbeespoort Dam, downstream of the current study site, and identified a high prevalence of Procamallanus (Procamallanus) laeviconchus and Paracamallanus cyathopharynx. Since then, Procamallanus (Procamallanus) pseudolaeviconchus was described from C. gariepinus suggesting reconsideration of the identifications of Procamallanus species in historical studies from clariids. The aim of the current study was to definitively identify the nematodes collected from C. gariepinus in Lake Heritage , using morphological and molecular analyses. Morphological study consisted of light and scanning electron microscopy which confirmed the identity P. (P.) pseudolaeviconchus and P. cyathopharynx. This included descriptions of the detailed morphology of isolated buccal capsules for both species using soft tissue digestion, notably for the first time for P. (P.) pseudolaeviconchus. The morphology of isolated spiculae of both species was described for the first time using SEM. Molecular analyses included genetic characterisation of the small ribosomal subunit (18S) rDNA and cytochrome oxidase 1 (CO1) mtDNA. Genetic data supported the morphological identification of both species, however, divergence was detected in CO1 mtDNA data for P. cyathopharynx indicating two distinct lineages. Due to this variation, the morphometry of P. cyathopharynx specimens were revisited including statistical re-evaluation. No robust morphological traits were identified to support CO1 mtDNA lineages and all specimens were considered conspecific. In terms of camallanid biodiversity in the Crocodile River system, it is similar to that in Boomker (1982), despite the altered water quality from past acid mine pollution in the river. [Display omitted] • Two camallanid species (Procamallanus (Procamallanus) pseudolaeviconchus and Paracamallanus cyathopharynx) collected from Clarias gariepinus in Lake Heritage, Crocodile River, South Africa. • Isolated buccal capsules studied for the first time for P. (P.) pseudolaeviconchus. • Isolated male spiculae studied for the first time for both species. • Genetic characterisation (18 S rDNA and CO1 mtDNA) with CO1 mtDNA genetic divergence for P. cyathopharynx. • Principal component analysis (PCA) is provided for the first time to study Paracamallanus sp. Morphometry to identify distinct morphometric traits. [ABSTRACT FROM AUTHOR]

The sclerotized structures of monogeneans have traditionally been studied by light microscopy and different staining techniques. Recently, enzymatic digestion followed by scanning electron microscopy (SEM) has enabled the examination of structural details not visible with light microscopy. In order to obtain better, and more accurate, morphological information on sclerotized structures not affected by mounting medium or cover slip pressure, the sclerites of Cichlidogyrus philander Douëllou, 1993 (Monogenea, Ancyrocephalidae), collected from Pseudocrenilabrus philander (Weber, 1897), were redescribed using SEM. Parasites were collected from Padda Dam, Gauteng, South Africa and soft tissue was digested to release the sclerotized structures. The digested tissue also provided sufficient genetic material for molecular characterization of this species. Cichlidogyrus philander is characterised by a penis with a sharp, curved, lateral termination, an accessory piece with a hook-like extremity that may appear forked terminally, and lack of a visible vagina. The transverse bars have concave and convex surfaces with ribs on the concave surface. The dorsal bar bears fenestrations at the base of the auricles and the ventral and dorsal gripi are dissimilar. Furthermore, the large first pair of uncinuli shows lateral wings on the left side of the base. On top of this wing, a ball-like structure with a small fenestration is visible. Genetic characters derived from the 28S rDNA, the COI mitochondrial DNA and ITS1 rDNA regions distinguish C. philander from all other Cichlidogyrus sequenced species.

A field experiment (N = 4,536) examined how signs of social class influence compassionate responses to those in need. Pedestrians in two major cities in the United States were exposed to a confederate wearing symbols of relatively high or low social class who was requesting money to help the homeless. Compassionate responding was assessed by measuring the donation amount of the pedestrians walking past the target. Pedestrians gave more than twice (2.55 times) as much money to the confederate wearing higher-class symbols than they did to the one wearing lower-class symbols. A followup study (N = 504) exposed participants to images of the target wearing the same higher- or lower-class symbols and examined the antecedents of compassionate responding. Consistent with theorizing, higher-class symbols elicited perceptions of elevated competence, trustworthiness, similarity to the self, and perceived humanity compared to lower-class symbols. These results indicate that visible signs of social class influence judgments of others' traits and attributes, as well as in decisions to respond compassionately to the needs of those who are suffering. [ABSTRACT FROM AUTHOR]

Carotenoids have been shown to be essential for human nutrition. Consumption of carotenoid-rich fruits and vegetables can reduce the risk of many diseases. The ketocarotenoid astaxanthin has become a commercially valuable compound due to its powerful antioxidant properties compared to other carotenoids. It is naturally produced in certain algae, bacteria, and the flowers of some species of the genus Adonis , although it is produced in such small quantities in these organisms that it is costly to extract. Chemical synthesis of this compound has also shown limited success with a high proportion of esterified forms of astaxanthin being produced, which decreases antioxidant properties by the conversion of hydroxyl groups to esters. Previously, transgenic astaxanthin-producing plants have been created using a β-carotene ketolase enzyme of either bacterial or algal origin. However, a novel astaxanthin pathway exists in the flowering plants of the genus Adonis which has not been utilized in the same manner. The pathway involves two unique enzymes, β-ring-4-dehydrogenase and 4-hydroxy-β-ring-4-dehydrogenase, which add the necessary hydroxyl and ketone groups to the rings of β-carotene. In the present study, Nicotiana benthamiana plants were transformed with chimeric constructs coding for these two enzymes. The regenerated, transgenic plants accumulate astaxanthin and their growth (height and weight) was unaffected, when compared to non-transformed N. benthamiana and to plants transformed with the bacterial β-carotene ketolase. The accumulation of astaxanthin also improved seedling survivability under harsh UV light, mitigated reactive oxygen accumulation, and provided a phenotype (color) that allowed the efficient identification and recovery of transgenic plants with and without selection. [ABSTRACT FROM AUTHOR]

Sleep is critical for memory consolidation, although the exact mechanisms mediating this process are unknown. Combining reduced network models and analysis of in vivo recordings, we tested the hypothesis that neuromodulatory changes in acetylcholine (ACh) levels during non-rapid eye movement (NREM) sleep mediate stabilization of network-wide firing patterns, with temporal order of neurons' firing dependent on their mean firing rate during wake. In both reduced models and in vivo recordings from mouse hippocampus, we find that the relative order of firing among neurons during NREM sleep reflects their relative firing rates during prior wake. Our modeling results show that this remapping of wake-associated, firing frequency-based representations is based on NREM-associated changes in neuronal excitability mediated by ACh-gated potassium current. We also show that learning-dependent reordering of sequential firing during NREM sleep, together with spike timing-dependent plasticity (STDP), reconfigures neuronal firing rates across the network. This rescaling of firing rates has been reported in multiple brain circuits across periods of sleep. Our model and experimental data both suggest that this effect is amplified in neural circuits following learning. Together our data suggest that sleep may bias neural networks from firing rate-based towards phase-based information encoding to consolidate memories. Author summary: We show that neuromodulatory changes during non-rapid eye movement (NREM) sleep generate stable spike timing relationships between neurons, the ordering of which reflects the neurons' relative firing rates during wake. Learning-dependent ordering of firing in the hippocampus during NREM, acting in tandem with spike timing-dependent plasticity, reconfigures neuronal firing rates across the hippocampal network. This "rescaling" of neuronal firing rates has recently been reported in multiple brain circuits across periods of sleep. Together, our results suggest that the brain is remapping frequency-biased representations of information formed during wake into timing biased-representations during NREM sleep. [ABSTRACT FROM AUTHOR]