Personality in Blue Tits (Cyanistes caeruleus) and its Effect on Their Breeding Success

In this study, we investigated whether blue tits (Cyanistes caeruleus) showed consistent variation in neophobia responses. The experiment represents a test of how personality, consistent individual differences in behaviour, may have fitness consequences. The experimental design consisted of a control observation followed by two neophobia tests, during which the parent's behaviour was recorded using the instantaneous sampling method. Blue tits showed consistent variation in neophobia responses, which was related to total offspring biomass, but not to mean offspring weight or fledging success. General linear mixed models analyses suggest that there may be ideal neophobia trait combinations in breeding pairs that maximise breeding success.     

ARL2, ARG1 and PIN3 define a gravity signal transduction pathway in root statocytes

ALTERED RESPONSE TO GRAVITY1 (ARG1) and its paralog ARG1-LIKE2 (ARL2) are J-domain proteins that are required for normal root and hypocotyl gravitropism. In this paper, we show that both ARL2 and ARG1 function in a gravity signal transduction pathway with PIN3, an auxin efflux facilitator that is expressed in the statocytes. In gravi-stimulated roots, PIN3 relocalizes to the lower side of statocytes, a process that is thought to, in part, drive the asymmetrical redistribution of auxin toward the lower flank of the root. We show that ARL2 and ARG1 are required for PIN3 relocalization and asymmetrical distribution of auxin upon gravi-stimulation. ARL2 is expressed specifically in the root statocytes, where it localizes to the plasma membrane. Upon ectopic expression, ARL2 is also found at the cell plate of dividing cells during cytokinesis, an area of intense membrane dynamics. Mutations in ARL2 and ARG1 also result in auxin-related expansion of the root cap columella, consistent with a role for ARL2 and ARG1 in regulating auxin flux through the root tip. Together these data suggest that ARL2 and ARG1 functionally link gravity sensation in the statocytes to auxin redistribution through the root cap.     

Effect of High Flow Events on In-Stream Dissolved Organic Nitrogen Concentration

Dissolved organic nitrogen (DON) can comprise a large and biologically important fraction of total dissolved N in surface water. Biotic and abiotic processes result in heterogeneous DON concentrations and bioavailability in soils, and as hydrologic connectivity expands and flow paths change in watersheds, novel sources of DON can be mobilized and transported to surface water. Although the relationship between in-stream DOC concentration and stream discharge has previously been examined in the literature, up to now there has not been a synthesis examining how DON concentrations, loads, and composition change during transitions from base flow to pulse flow conditions. We present a meta-analysis examining the effect of high flow on DON concentration ([DON]). The ratio of mean pulse flow [DON] to mean base flow [DON] (P:B) was calculated for individual events and averaged (geometric) within and then across sites to generate an overall effect size. For 47 sites (78 events), mean P:B was 1.58, which was significantly different from unity. This moderate increase in DON concentration contributed to over a more than 10-fold average increase in the rate of DON yield from base flow to high flow. The response of [DON] to high flow was significant in catchments where individual storm events or snowmelt runoff events were responsible for elevated flows, whereas the response was not significant in catchments where high discharge resulted from a mixture of upstream snowmelt and rain events. Additionally, an examination of DOC:DON ratios during high flow indicates that multiple sources of DON may be mobilized during high flow. Finally, current models of annual DON export may be improved by including a positive relationship between discharge and DON.     

Positional cues regulate dorsal organ formation in the liverwort Marchantia polymorpha

Journal of Plant Research - Bryophytes and vascular plants represent the broadest evolutionary divergence in the land plant lineage, and comparative analyses of development spanning this divergence...     

Abundance and site fidelity of Indo‐Pacific Humpback dolphins in the Great Sandy Strait,Queensland, Australia

This study examined the population of Indo‐Pacific humpback dolphins, Sousa chinensis, inhabiting the Great Sandy Strait Marine Park, Queensland, Australia. A total of 106 dolphins were identified during 228 boat‐based surveys, completed between April 2004 and April 2007. Based on the distribution of resighted individuals and the pattern of associations, it was established that this population consists of two largely geographically distinct communities, referred to as the Northern Community (NC) and the Southern Community (SC). The only recorded interaction between the two groups was a single pod composed of one member of the NC and 11 dolphins from the SC. Abundance was estimated for the entire population and by geographical area using open population models. Estimates for the Great Sandy Strait indicate that about 150 dolphins (N_GSS= 148.4, SE = 8.3, 95% CI: 132.5–165.2) used this area during the study. The NC and SC total population sizes was estimated to be 76 (N_NGSS= 75.80, SE = 3.88, 95% CI = 71–86) and 75 (N_SGSS= 74.98, SE = 4.43, 95% CI: 66–83), respectively. Analysis of residence patterns indicates that a majority of the identified dolphins are long‐term residents.     

Seasonal changes in pod characteristics of eastern Australian humpback whales (Megaptera novaeangliae), Hervey Bay 1992–2005

We investigated the characteristics and composition of 4,506 humpback whale pods observed in Hervey Bay between 1992 and 2005. We use these data to analyze and model the variability of pod size and composition, and to assess the importance of Hervey Bay for particular classes of humpback whales. Pods ranged in size from one to nine individuals. Pairs were the most frequent pod type (1,344, 29.8%), followed by mother‐calf alone (1,249, 27.7%), trios (759, 16.8%), singletons (717, 15.9%), and 4+ whales (437, 9.7%). Of the 4,506 pods, calves were present in 40%, and 10.8% of all pods had one or more escorts present. Of the 1,804 pods observed with calves present, 1,251 (69.4%) were mothers alone with their calves. The size and composition of pods in the study area varied significantly as the season progressed. Pods with calves present were rarely recorded early in the season but dominated later in the season. A significant increase over years in larger groups may be related to social and behavioral changes as the population expands. The data indicate that Hervey Bay is important to immature males and females early in the season, to mature males and females in mid‐season, and to mother‐calf pairs (either alone or with escorts) in mid‐to‐late season.     

A study of the influence of yeast cell debris on protein and alpha-glucosidase adsorption at various zones within the expanded bed using in-bed sampling

Expanded bed adsorption chromatography is used to capture products directly from unclarified feedstocks, thus combining solid-liquid separation, product concentration and preliminary purification into a single step. However, when non-specific ion-exchangers are used as the adsorbent in the expanded bed, there is the possibility that electrostatic interactions of cells or cell debris with the adsorbent may interfere with the adsorption of soluble products. These interactions depend on the particle size of the cell debris and its surface charge, which in turn depend on the extent of disruption used to release the intracellular products. The interactions occurring during expanded bed adsorption between the anionic ion-exchanger STREAMLINE DEAE and particulate yeast homogenates obtained by high pressure homogenisation at different intensities of disruption achieved by operating at different pressures were studied, while maintaining all other parameters constant. In-bed sampling from the expanded bed using ports fitted up the height of expanded bed was used to study the retention of yeast cells and cell debris within the bed and its influence on the adsorption of total soluble protein and alpha-glucosidase within various zones of the expanded bed. The retention of the biomass present in the homogenate obtained at a lower intensity of disruption was found to be high at the lower end of the column (17% from 13.8 MPa sample compared to 1% from 41.4 MPa sample). This interaction of the particulate material with the adsorbent was found to reduce the dynamic binding capacity of the adsorbent for total soluble protein from 3.6 mg/mL adsorbent for 41.4 MPa sample to 3.0 mg/mL adsorbent for 13.8 MPa sample. The adsorption of alpha-glucosidase was found to increase with an increase in the concentration of the enzyme in the feed, which increased with the intensity of disruption. Selective adsorption of 6,732 U alpha-glucosidase per mg of total protein bound, was noticed for the feedstock prepared at a higher disruption intensity at 41.4 MPa compared to adsorption of 1,262 U/mg of total protein bound for that prepared at 13.8 MPa. The selective adsorption of alpha-glucosidase due to its high concentration together with simultaneous high specific activity of the enzyme in the feed indicated the significance of selective release of enzymes during microbial cell disruption for efficient expanded bed adsorption processes.     

The peripheral and central antennular pathway of the Caribbean stomatopod crustacean Neogonodactylus oerstedii

Although stomatopod crustaceans use their chemical senses in many facets of behavior, little is known about their chemosensory neural pathways, especially in comparison to the better-studied decapod crustaceans. We examined the stomatopod Neogonodactylus oerstedii to determine organizational aspects of peripheral and central neural pathway of antennules, which is a major chemosensory organ. We describe the three flagella of the triramous antennule as the medial, dorsolateral, and ventrolateral flagella. The primary branch point is between the medial flagellum and lateral flagella, and the secondary branch point is at the junction of the dorsolateral and ventrolateral flagella. The antennule bears at least three types of setae, based on their external morphology. Simple setae are present only on the medial flagellum and ventrolateral flagellum, organized as a tuft of 10-15 setae on each flagellar annulus. Aesthetasc setae and asymmetric setae occur only on the distal annuli of the dorsolateral flagellum, with each annulus bearing a row of three aesthetascs and one asymmetric seta. DiI fills of the antennular nerve near the junction of the flagella show that sensory neurons in the antennular flagella project to two neuropils in the ipsilateral midbrain-the olfactory lobe (OL) and lateral antennular neuropil (LAN). The OL is glomerular and has rich serotonergic innervation, a characteristic of the OL in decapods. The LAN is bi-lobed and stratified as it is in decapods. However, the LAN of stomatopods differs from that of decapods in being relatively large and containing extensive serotonergic innervation. The median antennular neuropil of stomatopods has sparse serotonergic innervation, and it is more diffusely organized compared to decapods. No accessory lobes were found in N. oerstedii. Thus, the stomatopod antennular flagella have the same two, highly organized parallel pathways common to decapods-the OL pathway and the LAN pathway.     

Attaching and Effacing Escherichia coli Downregulate DNA Mismatch Repair Protein In Vitro and Are Associated with Colorectal Adenocarcinomas in Humans

Background

Mucosa-associated Escherichia coli are frequently found in the colonic mucosa of patients with colorectal adenocarcinoma, but rarely in healthy controls. Chronic mucosal E. coli infection has therefore been linked to colonic tumourigenesis. E. coli strains carrying eae (encoding the bacterial adhesion protein intimin) attach intimately to the intestinal mucosa and are classed as attaching and effacing E. coli (AEEC). Enteropathogenic Escherichia coli (EPEC) are the most common form of AEEC identified in man. EPEC utilise a type III secretion system to translocate effector proteins into host cells and infection induces wide-ranging effects on the host cell proteome. We hypothesised that EPEC infection could influence molecular pathways involved in colorectal tumourigenesis.

Methodology/Principal Findings

When co-cultured with human colorectal cell lines, EPEC dramatically downregulated the expression of key DNA mismatch repair proteins MSH2 and MLH1 in an attachment specific manner. Cytochrome c staining and TUNEL analysis confirmed that this effect was not a consequence of apoptosis/necrosis. Ex vivo human colonic mucosa was co-cultured with EPEC and probed by immunofluorescence to locate adherent bacteria. EPEC entered 10% of colonic crypts and adhered to crypt epithelial cells, often in the proliferative compartment. Adenocarcinoma and normal colonic mucosa from colorectal cancer patients (n = 20) was probed by immunofluorescence and PCR for AEEC. Mucosa-associated E. coli were found on 10/20 (50%) adenocarcinomas and 3/20 (15%) normal mucosa samples (P<0.05). AEEC were detected on 5/20 (25%) adenocarcinomas, but not normal mucosa samples (P<0.05).

Significance/Conclusions

The ability of EPEC to downregulate DNA mismatch repair proteins represents a novel gene-environment interaction that could increase the susceptibility of colonic epithelial cells to mutations and therefore promote colonic tumourigenesis. The potential role of AEEC in colorectal tumourigenesis warrants further investigation.     

Nucleocytoplasmic trafficking of the Syk protein tyrosine kinase

The protein tyrosine kinase Syk couples the B-cell receptor (BCR) for antigen to multiple intracellular signaling pathways and also modulates cellular responses to inducers of oxidative stress in a receptor-independent fashion. In B cells, Syk is found in both the nuclear and cytoplasmic compartments but contains no recognizable nuclear localization or export signals. Through the analysis of a series of deletion mutants, we identified the presence of an unconventional shuttling sequence near the junction of the catalytic domain and the linker B region that accounts for Syk's subcellular localization. This localization is altered following prolonged engagement of the BCR, which causes Syk to be excluded from the nucleus. Nuclear exclusion requires the receptor-mediated activation of protein kinase C and new protein synthesis. Both of these processes also potentiate the activation of caspase 3 in cells in response to oxidative stress in a manner that is dependent on the localization of Syk outside of the nucleus. In contrast, restriction of Syk to the nucleus greatly diminishes the stress-induced activation of caspase 3.