Hydraulic properties of layered soils influence survival of Rhodes grass (<Emphasis Type="Italic">Chloris gayana</Emphasis> Kunth.) during water stress

Survival of vegetation on soil-capped mining wastes is often impaired during dry seasons due to the limited amount of water stored in the shallow soil capping. Growth and survival of Rhodes grass (Chloris gayana) during soil drying on various layered capping sequences constructed of combinations of topsoil, subsoil, seawater-neutralised residue sand and low grade bauxite was determined in a glasshouse. The aim was to describe the survival of Rhodes grass in terms of plant and soil water relationships. The soil water characteristic curve and soil texture analysis was a good predictor of plant survival. The combination of soil with a high water holding capacity and low soil water diffusivity (e.g. subsoil with high clay contents) with soil having a high water holding capacity and high diffusivity (e.g. residue sand) gave best survival during drying down (up to 88 days without water), whereas topsoil and low grade bauxite were unsuitable (plants died within 18–39 days). Clayey soil improved plant survival by triggering a water stress response during peak evaporative water demand once residue sand dried down and its diffusivity fell below a critical range. Thus, for revegetation in seasonally dry climates, soil capping should combine one soil with low diffusivity and one or more soils with high total water holding capacity and high diffusivity.     

Structure of the Pseudorabies Virus Capsid: Comparison with Herpes Simplex Virus Type 1 and Differential Binding of Essential Minor Proteins

The structure of pseudorabies virus (PRV) capsids isolated from the nucleus of infected cells and from PRV virions was determined by cryo-electron microscopy (cryo-EM) and compared to herpes simplex virus type 1 (HSV-1) capsids. PRV capsid structures closely resemble those of HSV-1, including distribution of the capsid vertex specific component (CVSC) of HSV-1, which is a heterodimer of the pUL17 and pUL25 proteins. Occupancy of CVSC on all PRV capsids is near 100%, compared to ~ 50% reported for HSV-1 C-capsids and 25% or less that we measure for HSV-1 A- and B-capsids. A PRV mutant lacking pUL25 does not produce C-capsids and lacks visible CVSC density in the cryo-EM-based reconstruction. A reconstruction of PRV capsids in which green fluorescent protein was fused within the N-terminus of pUL25 confirmed previous studies with a similar HSV-1 capsid mutant localizing pUL25 to the CVSC density region that is distal to the penton. However, comparison of the CVSC density in a 9-Å-resolution PRV C-capsid map with the available crystal structure of HSV-1 pUL25 failed to find a satisfactory fit, suggesting either a different fold for PRV pUL25 or a capsid-bound conformation for pUL25 that does not match the X-ray model determined from protein crystallized in solution. The PRV capsid imaged within virions closely resembles C-capsids with the addition of weak but significant density shrouding the pentons that we attribute to tegument proteins. Our results demonstrate significant structure conservation between the PRV and HSV capsids.     

Toward a cross-species neuroscientific understanding of the affective mind: do animals have emotional feelings?

Do we need to consider mental processes in our analysis of brain functions in other animals? Obviously we do, if such BrainMind functions exist in the animals we wish to understand. If so, how do we proceed, while still retaining materialistic-mechanistic perspectives? This essay outlines the historical forces that led to emotional feelings in animals being marginalized in behavioristic scientific discussions of why animals behave the way they do, and why mental constructs are generally disregarded in modern neuroscientific analyses. The roots of this problem go back to Cartesian dualism and the attempt of 19th century physician-scientists to ground a new type of medical curriculum on a completely materialistic approach to body functions. Thereby all vitalistic principles were discarded from the lexicon of science, and subjective experience in animals was put in that category and discarded as an invalid approach to animal behavior. This led to forms of rigid operationalism during the era of behaviorism and subsequently ruthless reductionism in brain research, leaving little room for mentalistic concepts such as emotional feelings in animal research. However, modern studies of the brain clearly indicate that artificially induced arousals of emotional networks, as with localized electrical and chemical brain stimulation, can serve as "rewards" and "punishments" in various learning tasks. This strongly indicates that animal brains elaborate various experienced states, with those having affective contents being easiest to study rigorously. However, in approaching emotional feelings empirically we must pay special attention to the difficulties and vagaries of human language and evolutionary levels of control in the brain. We need distinct nomenclatures from primary (unconditioned phenomenal experiences) to tertiary (reflective) levels of mind. The scientific pursuit of affective brain processes in other mammals can now reveal general BrainMind principles that also apply to human feelings, as with neurochemical predictions from preclinical animal models to self-reports of corresponding human experiences. In short, brain research has now repeatedly verified the existence of affective experience-various reward and punishment functions-during artificial arousal of emotional networks in our fellow animals. The implications for new conceptual schema for understanding human/primate affective feelings and how such knowledge can impact scientific advances in biological psychiatry are also addressed.     

Cross-species affective neuroscience decoding of the primal affective experiences of humans and related animals

BACKGROUND: The issue of whether other animals have internally felt experiences has vexed animal behavioral science since its inception. Although most investigators remain agnostic on such contentious issues, there is now abundant experimental evidence indicating that all mammals have negatively and positively-valenced emotional networks concentrated in homologous brain regions that mediate affective experiences when animals are emotionally aroused. That is what the neuroscientific evidence indicates. PRINCIPAL FINDINGS: The relevant lines of evidence are as follows: 1) It is easy to elicit powerful unconditioned emotional responses using localized electrical stimulation of the brain (ESB); these effects are concentrated in ancient subcortical brain regions. Seven types of emotional arousals have been described; using a special capitalized nomenclature for such primary process emotional systems, they are SEEKING, RAGE, FEAR, LUST, CARE, PANIC/GRIEF and PLAY. 2) These brain circuits are situated in homologous subcortical brain regions in all vertebrates tested. Thus, if one activates FEAR arousal circuits in rats, cats or primates, all exhibit similar fear responses. 3) All primary-process emotional-instinctual urges, even ones as complex as social PLAY, remain intact after radical neo-decortication early in life; thus, the neocortex is not essential for the generation of primary-process emotionality. 4) Using diverse measures, one can demonstrate that animals like and dislike ESB of brain regions that evoke unconditioned instinctual emotional behaviors: Such ESBs can serve as 'rewards' and 'punishments' in diverse approach and escape/avoidance learning tasks. 5) Comparable ESB of human brains yield comparable affective experiences. Thus, robust evidence indicates that raw primary-process (i.e., instinctual, unconditioned) emotional behaviors and feelings emanate from homologous brain functions in all mammals (see Appendix S1), which are regulated by higher brain regions. Such findings suggest nested-hierarchies of BrainMind affective processing, with primal emotional functions being foundational for secondary-process learning and memory mechanisms, which interface with tertiary-process cognitive-thoughtful functions of the BrainMind.     

Reaction wood – a key cause of variation in cell wall recalcitrance in willow

Background

The recalcitrance of lignocellulosic cell wall biomass to deconstruction varies greatly in angiosperms, yet the source of this variation remains unclear. Here, in eight genotypes of short rotation coppice willow (Salix sp.) variability of the reaction wood (RW) response and the impact of this variation on cell wall recalcitrance to enzymatic saccharification was considered.

Results

A pot trial was designed to test if the ‘RW response’ varies between willow genotypes and contributes to the differences observed in cell wall recalcitrance to enzymatic saccharification in field-grown trees. Biomass composition was measured via wet chemistry and used with glucose release yields from enzymatic saccharification to determine cell wall recalcitrance. The levels of glucose release found for pot-grown control trees showed no significant correlation with glucose release from mature field-grown trees. However, when a RW phenotype was induced in pot-grown trees, glucose release was strongly correlated with that for mature field-grown trees. Field studies revealed a 5-fold increase in glucose release from a genotype grown at a site exposed to high wind speeds (a potentially high RW inducing environment) when compared with the same genotype grown at a more sheltered site.

Conclusions

Our findings provide evidence for a new concept concerning variation in the recalcitrance to enzymatic hydrolysis of the stem biomass of different, field-grown willow genotypes (and potentially other angiosperms). Specifically, that genotypic differences in the ability to produce a response to RW inducing conditions (a ‘RW response’) indicate that this RW response is a primary determinant of the variation observed in cell wall glucan accessibility. The identification of the importance of this RW response trait in willows, is likely to be valuable in selective breeding strategies in willow (and other angiosperm) biofuel crops and, with further work to dissect the nature of RW variation, could provide novel targets for genetic modification for improved biofuel feedstocks.

     

Comparative approaches in evolutionary psychology: molecular neuroscience meets the mind

Evolutionary psychologists often overlook a wealth of information existing between the proximate genotypic level and the ultimate phenotypic level. This commonly ignored level of biological organization is the ongoing activity of neurobiological systems. In this paper, we extend our previous arguments concerning strategic weaknesses of evolutionary psychology by advocating a foundational view that focuses on similarities in brain, behavior, and various basic psychological features across mammalian species. Such an approach offers the potential to link the emerging discipline of evolutionary psychology to its parent scientific disciplines such as biochemistry, physiology, molecular genetics, developmental biology and the neuroscientific analysis of animal behavior. We detail an example of this through our impending work using gene microarray technology to characterize gene expression patterns in rats during aggressive and playful social interactions. Through a focus on functional homologies and the experimental analysis of conserved, subcortical emotional and motivational brain systems, neuroevolutionary psychobiology can reveal ancient features of the human mind that are still shared with other animals. Claims regarding evolved, uniquely human, psychological constructs should be constrained by the rigorous evidentiary standards that are routine in other sciences.     

Expression of lauroyl-acyl carrier protein thioesterase in brassica napus seeds induces pathways for both fatty acid oxidation and biosynthesis and implies a set point for triacylglycerol accumulation

Expression of a California bay lauroyl-acyl carrier protein thioesterase (MCTE) in developing seeds of transgenic oilseed rape alters the fatty acid composition of the mature seed, resulting in up to 60 mol% of laurate in triacylglycerols. In this study, we examined the metabolism of lauric acid and 14C-acetate in developing seeds of oilseed rape that express high levels of MCTE. Lauroyl-CoA oxidase activity but not palmitoyl-CoA oxidase activity was increased several-fold in developing seeds expressing MCTE. In addition, isocitrate lyase and malate synthase activities were six- and 30-fold higher, respectively, in high-laurate developing seeds. Control seeds incorporated 14C-acetate almost entirely into fatty acids, whereas in seeds expressing MCTE, only 50% of the label was recovered in lipids and the remainder was in a range of water-soluble components, including sucrose and malate. Together, these results indicate that the pathways for beta-oxidation and the glyoxylate cycle have been induced in seeds expressing high levels of MCTE. Although a substantial portion of the fatty acid produced in these seeds is recycled to acetyl-CoA and sucrose through the beta-oxidation and glyoxylate cycle pathways, total seed oil is not reduced. How is oil content maintained if lauric acid is inefficiently converted to triacylglycerol? The levels of acyl carrier protein and several enzymes of fatty acid synthesis were increased two- to threefold at midstage development in high-laurate seeds. These results indicate that a coordinate induction of the fatty acid synthesis pathway occurs, presumably to compensate for the lauric acid lost through beta-oxidation or for a shortage of long-chain fatty acids.