Evolution of nesting behaviour and kleptoparasitism in a selected group of osmiine bees (Hymenoptera: Megachilidae)

The construction of nests to rear offspring is restricted to vertebrates and few insect taxa, such as termites, wasps, and bees. Among bees, species of the family Megachilidae are characterized by a particularly high diversity in nest construction behaviour. Many megachilid bees nest in excavated burrows in the ground, others place their brood cells in a variety of above‐ground cavities or attach them to the surface of a substrate, and yet others have adopted a kleptoparasitic habit. Evolutionary transitions between the different nesting sites and between conventional nesting and kleptoparasitism in bees are poorly understood. In the present study, we traced the evolution of nesting site selection and kleptoparasitism in the Annosmia–Hoplitis group (Osmiini), which displays an exceptionally high diversity in nesting behaviour. We found that the evolution of nesting behaviour proceeded unidirectionally from nesting in excavated burrows in the ground to nesting in rock depressions and cavities, followed by the colonization of snail shells and insect borings in dead wood or hollow stems. Kleptoparasitism evolved once and the kleptoparasitic species have derived from the same lineage as their hosts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108 , 349–360.     

9. LIST OF MEMBERS (as at date of publication)

We studied the breeding ecology of the Chestnut-backed Sparrowlark Eremopterix leucotis over three years between 2008 and 2010. The breeding season was bimodal with a main peak in laying in autumn (March–April) and another smaller peak in spring (September–October). Nest microhabitat analyses showed they prefer nesting in open areas with lots of bare ground (median 67.5%). Nest entrance directions were biased towards the south (mean vector (µ) = 186.44°). The majority of nests (78.2%) had an apron at the nest entrance. The mean clutch size was 1.88 but there was geographic variation in clutch size between northern and southern races of the species. The mean incubation and nestling periods were 10.33 d (range 10–11 d) and 9.20 d (range 8–10 d), respectively. The results suggest that parental contributions during incubation are almost equal, but females made significantly more food deliveries during the nestling period compared to males. The diet of nestlings comprised mainly of invertebrates (50.2%), seeds (34.4%) and unidentified food items (15.4%). Breeding success was low, averaging 16.1% (range 8.1–20.6%), and the average number of fledged young per pair was 0.36 ± 0.71. Replacement broods were common and we also recorded repeat brooding attempts.     

Can Melatonin Improve Shift Workers' Tolerance of the Night Shift? Some Preliminary Findings

The pineal hormone melatonin is potentially useful in the treatment of disorders, especially sleep disorders, associated with circadian rhythm disturbance. We have examined its effects on sleep, mood, and behaviour in a double-blind, placebo-controlled study of a small group of police officers working spans of seven successive night shifts. Compared to placebo, and to no treatment, melatonin (5 mg) taken at the desired bedtime improved problems related to sleep and increased alertness during working hours, especially during the early morning. In letter-target performance tests visual search speed and accuracy were either unchanged or slightly improved. Memory scanning speed and perception of mental load were adversely affected. This preliminary study suggests that melatonin has beneficial effects on sleep and alertness, but that its effects on performance need careful evaluation.     

3D-QSAR with CoMFA Model of Prolylendopeptidase Substrates

Abstract

The prolylendopeptidase (PEP) is the proteolytic enzyme, which plays an essential role in the regulation of some processes in central nervous system, such as memory, learning and behavior. It was shown that PEP activity changes at different diseases, like Parkinsons or Alzheimer's diseases, and some PEP inhibitors are used in therapy. At present time the discovery of new types of PEP inhibitors are the actual task.

In this study the structure of PEP active site was analyzed by 3D-QSAR with CoMFA methods using of 12 PEP substrates. The designed pharmacophore model assumes that substrates interact with PEP active site by pyrrolidol ring of proline residue and by hydrogen bonding.

The 3-D-QSAR + CoMFA model of PEP substrates propose that the hydrophobic bonds play the essential role in substrate interaction with enzyme. This model reveals the important steric and electrostatic areas around the molecules and the presence of substituents controls the PEP activity for substrates. Analysis of obtained data allows to assume, that substrate binding in PEP active site causes essential perturbations of substrate structure. This effect mainly depends on chemical nature of the amino acid side chain, located near to proline.     

Unaltered Instrumental Learning and Attenuated Body-Weight Gain in Rats During Non-rotating Simulated Shiftwork

Exposure to shiftwork has been associated with multiple health disorders and cognitive impairments in humans. We tested if we could replicate metabolic and cognitive consequences of shiftwork, as reported in humans, in a rat model comparable to 5 wks of non-rotating night shifts. The following hypotheses were addressed: (i) shiftwork enhances body-weight gain, which would indicate metabolic effects; and (ii) shiftwork negatively affects learning of a simple goal-directed behavior, i.e., the association of lever pressing with food reward (instrumental learning), which would indicate cognitive effects. We used a novel method of forced locomotion to model work during the animals' normal resting period. We first show that Wistar rats, indeed, are active throughout a shiftwork protocol. In contrast with previous findings, the shiftwork protocol attenuated the normal weight gain to 76?±?8?g in 5 wks as compared to 123?±?15?g in the control group. The discrepancy with previous work may be explained by the concurrent observation that with our shiftwork protocol rats did not adjust their between-work circadian activity pattern. They maintained a normal level of activity during the “off-work” periods. In the control experiment, rats were kept active during the dark period, normally dominated by activity. This demonstrated that forced activity, per se, did not affect body-weight gain (mean±SEM: 85?±?11?g over 5 wks as compared to 84?±?11?g in the control group). Rats were trained on an instrumental learning paradigm during the fifth week of the protocol. All groups showed equivalent increases in lever pressing from the first (3.8?±?.7) to the sixth (21.3?±?2.4) session, and needed a similar amount of sessions (5.1?±?.3) to reach a learning criterion (≥27 out of 30 lever presses). These results suggest that while on prolonged non-rotating shiftwork, not fully reversing the circadian rhythm might actually be beneficial to prevent body-weight gain and cognitive impairments. (Author correspondence: C.Leenaars@nin.knaw.nl)     

Controlled Exposure to Light and Darkness Realigns the Salivary Cortisol Rhythm in Night Shift Workers

The efficacy of a light/darkness intervention designed to promote circadian adaptation to night shift work was tested in this combined field and laboratory study. Six full-time night shift workers (mean age ± SD:37.1 ± 8.1 yrs) were provided an intervention consisting of an intermittent exposure to full-spectrum bright white light (～2000 lux) in the first 6 h of their 8 h shift, shielding from morning light by tinted lenses (neutral gray density, 15% visual light transmission), and regular sleep/darkness episodes in darkened quarters beginning 2 h after the end of each shift. Five control group workers (41.1 ± 9.9 yrs) were observed in the presence of a regular sleep/darkness schedule only. Constant routines (CR) performed before and after a sequence of ～12 night shifts over 3 weeks revealed that treatment group workers displayed significant shifts in the time of peak cortisol expression and realignment of the rhythm with the night-oriented schedule. Smaller phase shifts, suggesting an incomplete adaptation to the shift work schedule, were observed in the control group. Our observations support the careful control of the pattern of light and darkness exposure for the adaptation of physiological rhythms to night shift work.     

LabCaS: Labeling calpain substrate cleavage sites from amino acid sequence using conditional random fields

The calpain family of Ca²⁺‐dependent cysteine proteases plays a vital role in many important biological processes which is closely related with a variety of pathological states. Activated calpains selectively cleave relevant substrates at specific cleavage sites, yielding multiple fragments that can have different functions from the intact substrate protein. Until now, our knowledge about the calpain functions and their substrate cleavage mechanisms are limited because the experimental determination and validation on calpain binding are usually laborious and expensive. In this work, we aim to develop a new computational approach (LabCaS) for accurate prediction of the calpain substrate cleavage sites from amino acid sequences. To overcome the imbalance of negative and positive samples in the machine‐learning training which have been suffered by most of the former approaches when splitting sequences into short peptides, we designed a conditional random field algorithm that can label the potential cleavage sites directly from the entire sequences. By integrating the multiple amino acid features and those derived from sequences, LabCaS achieves an accurate recognition of the cleave sites for most calpain proteins. In a jackknife test on a set of 129 benchmark proteins, LabCaS generates an AUC score 0.862. The LabCaS program is freely available at: http://www.csbio.sjtu.edu.cn/bioinf/LabCaS . Proteins 2013. © 2012 Wiley Periodicals, Inc.