Simulating the Evolution of the Human Family: Cooperative Breeding Increases in Harsh Environments

Verbal and mathematical models that consider the costs and benefits of behavioral strategies have been useful in explaining animal behavior and are often used as the basis of evolutionary explanations of human behavior. In most cases, however, these models do not account for the effects that group structure and cultural traditions within a human population have on the costs and benefits of its members'' decisions. Nor do they consider the likelihood that cultural as well as genetic traits will be subject to natural selection. In this paper, we present an agent-based model that incorporates some key aspects of human social structure and life history. We investigate the evolution of a population under conditions of different environmental harshness and in which selection can occur at the level of the group as well as the level of the individual. We focus on the evolution of a socially learned characteristic related to individuals'' willingness to contribute to raising the offspring of others within their family group. We find that environmental harshness increases the frequency of individuals who make such contributions. However, under the conditions we stipulate, we also find that environmental variability can allow groups to survive with lower frequencies of helpers. The model presented here is inevitably a simplified representation of a human population, but it provides a basis for future modeling work toward evolutionary explanations of human behavior that consider the influence of both genetic and cultural transmission of behavior.     

Metabolically Protective Cytokines Adiponectin and Fibroblast Growth Factor-21 Are Increased by Acute Overfeeding in Healthy Humans

Context

Circulating levels of metabolically protective and adverse cytokines are altered in obese humans and rodent models. However, it is not clear whether these cytokines are altered rapidly in response to over-nutrition, or as a later consequence of the obese state.

Methods

Forty sedentary healthy individuals were examined prior to and at 3 and 28 days of high fat overfeeding (+1250 kCal/day, 45% fat). Insulin sensitivity (hyperinsulinaemic-euglycaemic clamp), adiposity, serum levels of adiponectin and fibroblast growth factor-21 (FGF21), fatty acid binding protein-4 (FABP4), lipocalin-2 and plasminogen activator factor-1 (PAI1) were assessed. Statistics were performed by repeated measures ANOVA.

Results

Overfeeding increased weight, body fat and liver fat, fasting glucose, insulin and reduced insulin sensitivity by clamp (all P <0.05). Metabolically protective cytokines, adiponectin and FGF21 were increased at day 3 of overfeeding (P ≤0.001) and adiponectin was also elevated at day 28 (P=0.001). FABP4, lipocalin-2 and PAI-1 were not changed by overfeeding at either time point.

Conclusion

Metabolically protective cytokines, adiponectin and FGF-21, were increased by over nutrition and weight gain in healthy humans, despite increases in insulin resistance. We speculate that this was in attempt to maintain glucose homeostasis in a state of nutritional excess. PAI-I, FABP4 and lipocalin 2 were not altered by overfeeding suggesting that changes in these cytokines may be a later consequence of the obese state. Clinical trial registration: www.clinicaltrials.gov (NCT00562393)     

Molecular characterisation of acanthocephalans from Australian marine teleosts: proposal of a new family,synonymy of another and transfer of taxa between orders

We provide molecular data (cox1, 18S rDNA and 28S rDNA) for 17 acanthocephalan species and 20 host-parasite combinations from Australian marine teleosts collected from off Queensland, Australia. Fourteen of these acanthocephalans are characterised with molecular data for the first time and we provide the first molecular data for a species of each of the genera Heterosentis Van Cleave, 1931, Pyriproboscis Amin, Abdullah & Mhaisen, 2003 and Sclerocollum Schmidt & Paperna, 1978. Using 18S and 28S rDNA sequences, the phylogenetic position of each newly sequenced species is assessed with both single-gene and concatenated 18S+28S maximum likelihood and Bayesian inference analyses. Additional phylogenetic analyses focusing on the genus Rhadinorhynchus Lühe, 1912 and related lineages are included. Our phylogenetic results are broadly consistent with previous analyses, recovering previously identified inconsistencies but also providing new insights and necessitating taxonomic action. We do not find sufficient evidence to recognise the Gymnorhadinorhynchidae Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014 as distinct from the Rhadinorhynchidae Lühe, 1912. The family Gymnorhadinorhynchidae and its sole genus, Gymnorhadinorhynchus Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014, are here recognised as junior synonyms of Rhadinorhynchidae and Rhadinorhynchus, respectively. The two species currently assigned to Gymnorhadinorhynchus are recombined as Rhadinorhynchus decapteri (Braicovich, Lanfranchi, Farber, Marvaldi, Luque & Timi, 2014) n. comb. and Rhadinorhynchus mariserpentis (Steinauer, Garcia-Vedrenne, Weinstein & Kuris, 2019) n. comb. In all of our analyses, Rhadinorhynchus biformis Smales, 2014 is found basal to the Rhadinorhynchidae + Transvenidae Pichelin & Cribb, 2001, thus resulting in a paraphyletic Rhadinorhynchidae. It appears that R. biformis may require a new genus and family; however, morphological data for this species are currently insufficient to adequately distinguish it from related lineages, thus we defer the proposal of any new higher-rank names for this species. Species of the genus Sclerocollum, currently assigned to the Cavisomidae Meyer, 1932, are found nested within the family Transvenidae. We transfer the genus Sclerocollum to the Transvenidae and amend the diagnosis of the family accordingly. The genera Gorgorhynchoides Cable & Linderoth, 1963 and Serrasentis Van Cleave, 1923, currently assigned to the Rhadinorhynchidae, are supported as sister taxa and form a clade in the Polymorphida. We transfer these genera and Golvanorhynchus Noronha, Fabio & Pinto, 1978 to an emended concept of the Isthomosacanthidae Smales, 2012 and transfer this family to the Polymorphida. Lastly, Pyriproboscis heronensis (Pichelin, 1997) Amin, Abdullah & Mhaisen, 2003, currently assigned to the Pomphorhynchidae Yamaguti, 1939, falls under the Polymorphida in our analyses with some support for a sister relationship with the Centrorhynchidae Van Cleave, 1916. As this species clearly does not belong in the Pomphorhynchidae and is morphologically and molecularly distinct from the lineages of the Polymorphida, we propose the Pyriprobosicidae n. fam. to accommodate it.

     

Microbially Mediated Calcium Carbonate Precipitation: Implications for Interpreting Calcite Precipitation and for Solid-Phase Capture of Inorganic Contaminants

Microbial degradation of urea was investigated as a potential geochemical catalyst for Ca carbonate precipitation and associated solid phase capture of common groundwater contaminants (Sr, UO₂, Cu) in laboratory batch experiments. Bacterial degradation of urea increased pH and promoted Ca carbonate precipitation in both bacterial control and contaminant treatments. Associated solid phase capture of Sr was highly effective, capturing 95% of the 1 mM Sr added within 24 h. The results for Sr are consistent with solid solution formation rather than discrete Sr carbonate phase precipitation. In contrast, UO₂ capture was not as effective, reaching only 30% of the initial 1 mM UO₂ added, and also reversible, dropping to 7% by 24 h. These results likely reflect differing sites of incorporation of these two elements-Ca lattice sites for Sr versus crystal defect sites for UO₂. Cu sequestration was poor, resulting from toxicity of the metal to the bacteria, which arrested urea degradation and concomitant Ca carbonate precipitation. Scanning electron microscopy (SEM) indicated a variety of morphologies reminiscent of those observed in the marine stromatolite literature. In bacterial control treatments, X-ray diffraction (XRD) analyses indicated only calcite; while in the presence of either Sr or UO₂, both calcite and vaterite, a metastable polymorph of Ca carbonate, were identified. Tapping mode atomic force microscopy (AFM) indicated differences in surface microtopography among abiotic, bacterial control, and bacterial contaminant systems. These results indicate that Ca carbonate precipitation induced by passive biomineralization processes is highly effective and may provide a useful bioremediation strategy for Ca carbonate-rich aquifers where Sr contamination issues exist.     

The Naphthoquinone Diospyrin Is an Inhibitor of DNA Gyrase with a Novel Mechanism of Action

Tuberculosis and other bacterial diseases represent a significant threat to human health. The DNA topoisomerases are excellent targets for chemotherapy, and DNA gyrase in particular is a well-validated target for antibacterial agents. Naphthoquinones (e.g. diospyrin and 7-methyljuglone) have been shown to have therapeutic potential, particularly against Mycobacterium tuberculosis. We have found that these compounds are inhibitors of the supercoiling reaction catalyzed by M. tuberculosis gyrase and other gyrases. Our evidence strongly suggests that the compounds bind to the N-terminal domain of GyrB, which contains the ATPase active site, but are not competitive inhibitors of the ATPase reaction. We propose that naphthoquinones bind to GyrB at a novel site close to the ATPase site. This novel mode of action could be exploited to develop new antibacterial agents.     

Guided Self-Help Cognitive Behavioural Therapy for Depression in Primary Care: A Randomised Controlled Trial

Background

Access to Cognitive behavioural therapy (CBT) for depression is limited. One solution is CBT self-help books. Trial Objectives: To assess the impact of a guided self-help CBT book (GSH-CBT) on mood, compared to treatment as usual (TAU).Hypotheses:

1. GSH-CBT will have improved mood and knowledge of the causes and treatment of depression compared to the control receiving TAU
2. Guided self-help will be acceptable to patients and staff.

Methods and Findings

Participants: Adults attending seven general practices in Glasgow, UK with a BDI-II score of ≥14. 141 randomised to GSH-CBT and 140 to TAU. Interventions: RCT comparing ‘Overcoming Depression: A Five Areas Approach’ book plus 3–4 short face to face support appointments totalling up to 2 hours of guided support, compared with general practitioner TAU. Primary outcome: The BDI (II) score at 4 months. Numbers analysed: 281 at baseline, 203 at 4 months (primary outcome), 117 at 12 months. Outcome: Mean BDI-II scores were lower in the GSH-CBT group at 4 months by 5.3 points (2.6 to 7.9, p<0.001). At 4 and 12 months there were also significantly higher proportions of participants achieving a 50% reduction in BDI-II in the GSH-CBT arm. The mean support was 2 sessions with 42.7 minutes for session 1, 41.4 minutes for session 2 and 40.2 minutes of support for session 3. Adverse effects/Harms: Significantly less deterioration in mood in GSH-CBT (2.0% compared to 9.8% in the TAU group for BDI—II category change).

Limitations

Weaknesses: Our follow-up rate of 72.2% at 4 months is better than predicted but is poorer at 12 months (41.6%). In the GSH-CBT arm, around 50% of people attended 2 or fewer sessions. 22% failed to take up treatment.

Conclusions

GSH-CBT is substantially more effective than TAU.

Trial Registration

Controlled-Trials.com ISRCTN13475030     

The Distribution and Density of Water Mice (Xeromys myoides) in the Maroochy River of Southeast Queensland,Australia

The water mouse is a small and vulnerable rodent present in coastal areas of south-west Papua New Guinea, and eastern Queensland and the Northern Territory of Australia. Current knowledge regarding the distribution of the water mouse is incomplete and the loss of one local population has been documented in southeast Queensland, a region where pressures from urban and industrial development are increasing. Water mouse populations have not been studied intensively enough to enable the primary factors responsible for the local decline to be identified. We surveyed the distribution and density of the water mouse along the Maroochy River of southeast Queensland, near the southern extent of the species’ range, to gather baseline data that may prove valuable for detecting any future decline in this population’s size or health. All areas of suitable habitat were surveyed on foot or by kayak or boat over a three-year period. We found 180 water mouse nests, of which ~94% were active. Permanent camera monitoring of one nest and limited supplementary live trapping suggested that up to three individual mice occupied active nests. Water mouse density was estimated to be 0.44 per hectare of suitable habitat along the Maroochy River. Should future monitoring reveal an adverse change in the water mouse population on the Maroochy River, a concerted effort should be made to identify contributing factors and address proximate reasons for the decline.