Why be diurnal? Or, why not be cathemeral?

As a behavioural strategy, cathemerality is thought to confer considerable advantages by allowing animals to extend activity flexibly into either the diurnal or nocturnal phase in response to the prevailing ecological conditions. Factors such as temperature, access to food sources and minimising the risk of predation are all thought to be important in promoting cathemerality, although previous studies have produced inconsistent results. This paper adopts a different approach by first asking whether an obligate diurnal species, the chacma baboon (Papio hamadryas ursinus), exhibits seasonal variation in behavioural flexibility in response to annual cycles of day length. While short day lengths are an important constraint on the activity of the baboons at De Hoop Nature Reserve, South Africa, long summer days permit considerable flexibility in thermoregulatory response, diet selection and patterns of habitat choice. Given that baboons adapt flexibly in response to a relaxation of time constraints, the question thus arises as to why diurnal and nocturnal primates do not adopt cathemeral activity patterns when time is constrained? For baboons, the costs of predation appear to prohibit exploitation of the nocturnal phase and it is likely that such constraints are true of most primates. It thus follows that Madagascar's predatory environment must in some way permit or select for a cathemeral lifestyle. The importance of the predation by fossa (Cryptoprocta ferox) on the evolution of cathemerality is discussed.     

Shall Organized Medicine be Unified, or Separate?

At present, physicians in California who choose to join organized medicine do so through their county medical societies, and membership in the California Medical Association and the American Medical Association is then automatic. At the March meeting of the CMA House of Delegates, question was raised whether membership in CMA, and the AMA, or both should remain automatic.The House requested an ad hoc committee to cause a "poll and its attendant statements to be developed by May 21 for copy distribution to component medical societies and printing in the CMA membership news media-with mailing of the official questionnaires to the society members on September 1, 1971." Members will be asked to express their opinions by ballot in September.The Speaker of the House appointed an ad hoc committee of the House to conduct this informed opinion poll of the membership. The committee has met to set ground rules, prepare accurate pro and con statements and write the poll questions-in accord with the directions of the House action.The Informed Membership Opinion Poll Committee, with the advice of Decision Making Information, Inc., an independent consultant, prepared statements regarding unified and separate membership in CMA and AMA from comments which were solicited from every county medical society. A statement by legal counsel for the California Medical Association on the structural relationship of AMA, CMA and component societies, and the statements on unified or separate membership prepared by the committee appear on the following two pages.     

Can 1000 reviews be wrong? Actin, alpha-Catenin, and adherens junctions

Coupling between cell adhesion and the actin cytoskeleton is thought to require a stable link between the cadherin-catenin complex and actin that is mediated by alpha-catenin. In this issue of Cell, the Weis and Nelson groups call this static model into question, showing that alpha-catenin can directly regulate actin dynamics (Drees et al., 2005 and Yamada et al., 2005).     

Born to be bee,fed to be worker? The caste system of a primitively eusocial insect

Introduction

Primitively eusocial halictid bees are excellent systems to study the origin of eusociality, because all individuals have retained the ancestral ability to breed independently. In the sweat bee Halictus scabiosae, foundresses overwinter, establish nests and rear a first brood by mass-provisioning each offspring with pollen and nectar. The mothers may thus manipulate the phenotype of their offspring by restricting their food provisions. The first brood females generally help their mother to rear a second brood of males and gynes that become foundresses. However, the first brood females may also reproduce in their maternal or in other nests, or possibly enter early diapause. Here, we examined if the behavioural specialization of the first and second brood females was associated with between-brood differences in body size, energetic reserves and pollen provisions.

Results

The patterns of variation in adult body size, weight, fat content and food provisioned to the first and second brood indicate that H. scabiosae has dimorphic females. The first-brood females were significantly smaller, lighter and had lower fat reserves than the second-brood females and foundresses. The first-brood females were also less variable in size and fat content, and developed on homogeneously smaller pollen provisions. Foundresses were larger than gynes of the previous year, suggesting that small females were less likely to survive the winter.

Conclusions

The marked size dimorphism between females produced in the first and second brood and the consistently smaller pollen provisions provided to the first brood suggest that the first brood females are channelled into a helper role during their pre-imaginal development. As a large body size is needed for successful hibernation, the mother may promote helping in her first brood offspring by restricting their food provisions. This pattern supports the hypothesis that parental manipulation may contribute to promote worker behaviour in primitively eusocial halictids.

     

To be or not to be ubiquitinated?

Levels of p21, a cyclin-dependent kinase (CDK) inhibitor, are controlled in part at the post-translational level by protein degradation. Although the signaling pathways leading to p21 degradation have not yet been fully elucidated, it is evident that p21 ubiquitination is an essential factor in its degradation. We discuss that, with the only notable exception of ornithine decarboxylase, ubiquitination appears to be a prerequisite for proteasomal degradation rather than an unnecessary byproduct of such proteolysis.     

To be folded or to be unfolded?

The lack of ordered structure in “natively unfolded” proteins raises a general question: Are there intrinsic properties of amino acid residues that are responsible for the absence of fixed structure at physiological conditions? In this article, we demonstrate that the competence of a protein to be folded or to be unfolded may be determined by the property of amino acid residues to form a sufficient number of contacts in a globular state. The expected average number of contacts per residue calculated from the amino acid sequence alone (using the average number of contacts for 20 amino acid residues in globular proteins) can be used as one of the simple indicators of natively unfolded proteins. The prediction accuracy for the sets of 80 folded and 90 natively unfolded proteins reaches 89% if the expected average number of contacts is used as a parameter and 83% in the case of hydrophobicity. An optimal set of artificial parameters for 20 amino acid residues obtained by Monte Carlo algorithm to maximally separate the sets of 90 natively unfolded and 80 folded proteins demonstrates the upper limit for prediction accuracy, which is 95%.     

To be or NUCB2, is nesfatin the answer?

Signals from the hypothalamus govern food intake and energy balance. A new study describes nesfatin-1, a hypothalamic and brainstem peptide whose expression decreases during fasting. Although central treatment with nesfatin-1 inhibited food intake and nesfatin-1 blockade increased food intake, the role and mechanism of nesfatin in energy balance remains unclear.     

When HIPAA finally comes, will clinical engineering be ready?

We live in interesting times. Recognize that HIPAA will impact nearly everyone in every health care organization and fundamentally change the health care industry. Implementation of HIPAA standards as well as ongoing developments in telemedicine, e-health and the Internet will continue to have a synergistic effect and further transform our industry. Biomedical technology will evolve and combine into ever-larger integrated networks. These networks will extend not only throughout the hospitals but also into the clinics, doctors' offices, and even patients' homes and workplaces. As clinical engineers, we need to stay ahead of the curve, anticipate and be prepared for these developments. We need to understand HIPAA and the implications it has for the technology we manage. We must ensure that the organizations we represent are prepared for what will undoubtedly be an exciting future.     

‘Don't be so serious’: ethical play,Islam, and the transcendent

Modes of play and playfulness are central to ethics, yet have not been as rigorously considered by anthropologists as have more earnest forms of ethical life. In this article, I argue that attention to play reframes recent anthropological debates about ethical transcendence and immanence. I do so through a consideration of the Islamic discourse of ‘calculation’ (ḥisāb), an idiom by which Muslims articulate their hoped-for state in the hereafter through the imagery of a divine accounting of good and bad deeds. Drawing on ethnography from the Indonesian province of Aceh, I show how ḥisāb cultivates forms of epistemological play through which Muslims explore the inscrutability of transcendence. Such play reveals the socially and theologically emergent qualities of transcendent truths and values, suggesting hidden affinities between transcendent stances and more immanent forms of ethical life.     

Neurogenic dysregulation, oxidative stress, autoimmunity, and melanocytorrhagy in vitiligo: can they be interconnected?

Several hypotheses have been proposed to explain vitiligo, including the neural theory, impaired redux status, autoimmunity, and more recently melanocytorrhagy arising from defective cell-cell adhesion. It is most likely that the loss of melanocytes in vitiligo arises through a combination of pathogenic mechanisms that act in concert. Here, we discuss the potential interconnection of several mechanisms that are likely to operate. These include the alteration of melanocyte-specific factors by reactive oxygen species to produce neo-antigens and the role of hypoxia and oxidative stress in antigen presentation and the auto-immune destruction of melanocytes.     

Neurogenic dysregulation,oxidative stress,autoimmunity, and melanocytorrhagy in vitiligo: can they be interconnected?

Several hypotheses have been proposed to explain vitiligo, including the neural theory, impaired redux status, autoimmunity, and more recently melanocytorrhagy arising from defective cell‐cell adhesion. It is most likely that the loss of melanocytes in vitiligo arises through a combination of pathogenic mechanisms that act in concert. Here, we discuss the potential interconnection of several mechanisms that are likely to operate. These include the alteration of melanocyte‐specific factors by reactive oxygen species to produce neo‐antigens and the role of hypoxia and oxidative stress in antigen presentation and the auto‐immune destruction of melanocytes.     

May photoinhibition be a consequence, rather than a cause, of limited plant productivity?

Photoinhibition in leaves in response to high and/or excess light, consisting of a decrease in photosynthesis and/or photosynthetic efficiency, is frequently equated to photodamage and often invoked as being responsible for decreased plant growth and productivity. However, a review of the literature reveals that photoinhibited leaves characterized for foliar carbohydrate levels were invariably found to possess high levels of sugars and starch. We propose that photoinhibition should be placed in the context of whole-plant source–sink regulation of photosynthesis. Photoinhibition may represent downregulation of the photosynthetic apparatus in response to excess light when (1) more sugar is produced in leaves than can be utilized by the rest of the plant and/or (2) more light energy is harvested than can be utilized by the chloroplast for the fixation of carbon dioxide into sugars.     

Nepotism vs Tit-For-Tat,or, why should you be nice to your rotten brother?

Summary It is well known that interactions among relatives facilitate the evolution of altruistic behaviours. Game theoretic models show, however, that guarded altruism (such as Tit-For-Tat) can evolve among non-relatives when individuals interact many times and cheating behaviours can be punished. Strangely, no one has yet asked whether the guarded altruism that evolves among non-relatives might also evolve among close relatives, supplanting unconditional altriusm. We present a series of one-locus sexual haploid models in which Tit-For-Tat, unconditional altruists and selfish individuals interact in groups of full siblings. Tit-For-Tat frequently (but not always) replaced unguarded altruism, in which case the strategic rules for interacting with kin vs non-kin are identical. Even when Tit-For-Tat is selected at a single locus, however, by withholding altruism for non-reciprocating relatives it may qualify as an outlaw from the standpoint of modifier genes at other loci.     

Would a medium-nicotine,low-tar cigarette be less hazardous to health?

Smoking behaviour and exposure to carbon monoxide, nicotine, and tar were studied in 19 middle-tar smokers. All smoked their own brands for three weeks and then switched to either a conventional low-nicotine, low-tar brand (control) or a medium-nicotine, low-tar cigarette for a further three weeks, the order then being reversed. The medium-nicotine, low-tar brand also had a low delivery of carbon monoxide. With the medium-nicotine, low-tar cigarette mouth-level delivery and intake of nicotine was similar to that with the smokers'' usual brands, and significantly greater than with the control low-tar cigarette. Intake of carbon monoxide from the medium-nicotine, low-tar cigarette was significantly less than with either own or control brands. With both low-tar brands mouth-level exposure to tar was reduced relative to smokers'' usual cigarettes. There was no evidence, however, that the reduction in tar exposure was greater with the medium-nicotine brand than with the control low-tar cigarette. Both low tar brands were "''oversmoked" relative to subjects'' usual middle-tar cigarettes. The medium-nicotine, low-tar cigarette was marginally more acceptable than the control brand, and the particular design used in the study resulted in a lower intake of carbon monoxide. In terms of reducing mouth-level exposure to tar, however, the medium-nicotine, low-tar cigarette had no advantage over the control low-tar product. In part this was because of the ratio of tar to nicotine delivery obtained by human smokers was not the same as that obtained by smoking machine.     

Phenylphenalenone phytoalexins, will they be a new type of fungicide?

Phenylphenalenones represent a kind of phytoalexins produced in leaves and rhyzomes of banana and plantains (Musaceae), as well as in species of other families. These compounds are synthesized in plants by induction with aminoglycosides, or in the first stages of attack by the pathogenic fungus Mycosphaerella fijensis, a causal agent of the disease known as Black Sigatoka, which reduces banana production. In this paper we report the biosynthesis, synthesis and antifungal activities of these kinds of compounds and discus the possibility to use phytoalexins inductors as plant protectants.     

‘To be,or not to be’—The dilemma of ‘silent’ antimicrobial resistance genes in bacteria

Antimicrobial resistance is a serious threat to public health that dramatically undermines our ability to treat bacterial infections. Microorganisms exhibit resistance to different drug classes by acquiring resistance determinants through multiple mechanisms including horizontal gene transfer. The presence of drug resistance genotypes is mostly associated with corresponding phenotypic resistance against the particular antibiotic. However, bacterial communities harbouring silent antimicrobial resistance genes—genes whose presence is not associated with a corresponding resistant phenotype do exist. Under suitable conditions, the expression pattern of such genes often revert and regain resistance and could potentially lead to therapeutic failure. We often miss the presence of silent genes, since the current experimental paradigms are focused on resistant strains. Therefore, the knowledge on the prevalence, importance and mechanism of silent antibiotic resistance genes in bacterial pathogens are very limited. Silent genes, therefore, provide an additional level of complexity in the war against drug-resistant bacteria, reminding us that not only phenotypically resistant strains but also susceptible strains should be carefully investigated. In this review, we discuss the presence of silent antimicrobial resistance genes in bacteria, their relevance and their importance in public health.