The function of nonlinear phenomena in meerkat alarm calls

Nonlinear vocal phenomena are a ubiquitous feature of human and non-human animal vocalizations. Although we understand how these complex acoustic intrusions are generated, it is not clear whether they function adaptively for the animals producing them. One explanation is that nonlinearities make calls more unpredictable, increasing behavioural responses and ultimately reducing the chances of habituation to these call types. Meerkats (Suricata suricatta) exhibit nonlinear subharmonics in their predator alarm calls. We specifically tested the ‘unpredictability hypothesis’ by playing back naturally occurring nonlinear and linear medium-urgency alarm call bouts. Results indicate that subjects responded more strongly and foraged less after hearing nonlinear alarm calls. We argue that these findings support the unpredictability hypothesis and suggest this is the first study in animals or humans to show that nonlinear vocal phenomena function adaptively.     

Isolation, modulatory functions on murine B cell development and antigen-specific immune responses of BP11, a novel peptide from the chicken bursa of Fabricius

The bursa of Fabricius (BF) is the central humoral immune organ unique to birds which plays important roles in B lymphocyte differentiation. Here, a new bursal peptide (BP11) with the amino acid sequence DVAGKLPDNRT was identified and characterized from BF. It was proved that BP11 promoted CFU pre-B formation, and regulated B cell differentiation, including increase the percentage of immature and mature B cells in BM cells co-cultured with IL-7. BP11 also exerted immunomodulatory function on antigen-specific immune responses in BALB/c mice immunized with inactivated influence virus (AIV, H9N2 subtype) vaccine, including enhancing AIV-specific antibody and cytokine production. Furthermore, it was noteworthy that BP11 stimulated antibody productions and potentiates the Th1 and Th2-type immune responses in dose-dependent manner in chicken. These results suggested that BP11 might be highly relevant for the development of avian immune system.     

温度对中华大蟾蜍和中华鳖冬眠前离体红细胞免疫功能及其大小的影响

为了探讨温度变化对中华大蟾蜍(Bufo gargarizans)和中华鳖(Trionyx sinensis)离体红细胞免疫功能及细胞大小的影响,我们设计了10℃、20℃、30℃、37℃ 4个温度组,通过红细胞C3b受体花环试验和红细胞免疫复合物花环试验检测红细胞免疫活性,同时测量其红细胞大小.结果表明,温度对中华大蟾蜍离体红细胞C3b受体花环率影响显著,随着温度的升高,中华大蟾蜍离体红细胞C3b受体花环率逐渐降低,在30℃和37℃时,其红细胞C3b受体花环率明显比10℃时低;而温度对其离体红细胞免疫复合物花环率和红细胞大小却没有显著影响.温度对中华鳖离体红细胞C3b受体花环率、免疫复合物花环率及其大小亦没有显著影响.除了10℃时中华鳖离体红细胞免疫复合物花环率与中华大蟾蜍没有明显差别外,其余各温度下中华鳖离体红细胞C3b受体花环率和免疫复合物花环率均明显比中华大蟾蜍的高,而其红细胞的长径和短径却明显比中华大蟾蜍红细胞的小.这说明,温度能明显影响中华大蟾蜍离体红细胞免疫功能,而对中华鳖离体红细胞的免疫活性影响不明显,随着动物进化程度的提高,中华鳖红细胞对温度变化的适应能力和免疫活性比中华大蟾蜍明显增强.     

秦岭川金丝猴1至2岁个体的社会玩耍行为

2009年3月至2010年5月在秦岭北坡的陕西周至国家级自然保护区玉皇庙,采用焦点动物取样法(Focal animal sampling)和瞬时记录法(Instantaneous sampling)对2008年出生的5只秦岭川金丝猴幼体(3 ♂、2♀)的社会玩耍行为进行了研究.结果表明:1-2岁的川金丝猴对其不同年龄-性别组的玩耍伙伴具有很高的选择性,喜欢与单元内的青少年个体玩耍;其次喜欢与新生个体玩耍,与母亲、单元内主雄和其它成年雌性个体玩耍的机会不多.另外,该年龄段的个体在玩耍中常采用追逐和摔跤的方式,采用接近、撕咬和其它行为的方式均不高.雄性个体比雌性个体更常采用摔跤的行为方式,而雌性个体相比雄性个体更常采用接近等方式.在整个观察期,社会交往性的玩耍行为频次未发现个体差异和性别差异.此外,这些个体玩耍频次的发育与年龄阶段之间不存在线性相关.个体在这种行为的发育过程中不仅可锻炼身体、实践打斗技巧,建立社会关系,并且能获得一定的认知能力.     

Experimental removal of the male parent negatively affects growth and immunocompetence in nestling great tits

Given the available empirical evidence on the benefits and costs associated with immune defence, a role for the immune system in the trade-off between current and future reproduction has been predicted. This hypothesis was studied in a free-living population of great tits (Parus major) by examining the effects of male removal on the immunocompetence, body condition, and recapture probability in the widowed females and their nestlings. Furthermore, we investigated whether growth and its relation to immunocompetence were affected in the nestlings. For a short-lived species such as the great tit, one could predict that widowed females will compensate for the lack of any male assistance in feeding of their chicks and that they consequently might jeopardize their own health. However, we did not find any negative effects of male removal on body mass or condition, nor on humoral immunocompetence against sheep red blood cells in the widowed females by the end of the feeding period. In contrast, we observed significantly reduced body mass and size as well as a reduced T-lymphocyte cell-mediated immune response (expressed as the thickness of the swelling to a subcutaneous injection with phytohemagglutinin) in the experimental nestlings compared to the control nestlings. In addition, the experimental nestlings showed a tendency for a reduced chance to be found breeding the following year. Furthermore, our results showed that in the experimental nestlings, which suffered from unfavourable growth conditions, tarsus length was inversely related to cell-mediated immunocompetence, whereas in control nestlings this relationship was significantly positive. The relationship between cell-mediated immunity and body condition was found to be significantly positive in the experimental nestlings while in control nestlings there was no relationship between both variables. The latter finding suggests different priorities of investment in body condition between different growth conditions.     

The significance of focal myoepithelial cell layer disruptions in human breast tumor invasion: a paradigm shift from the "protease-centered" hypothesis

Human breast epithelium and the stroma are separated by a layer of myoepithelial (ME) cells and basement membrane, whose disruption is a prerequisite for tumor invasion. The dissolution of the basement membrane is traditionally attributed primarily to an over-production of proteolytic enzymes by the tumor or the surrounding stromal cells. The results from matrix metalloproteinase inhibitor clinical trials, however, suggest that this "protease-centered" hypothesis is inadequate to completely reflect the molecular mechanisms of tumor invasion. The causes and signs of ME cell layer disruption are currently under-explored. Our studies revealed that a subset of pre- and micro-invasive tumors contained focal disruptions in the ME cell layers. These disruptions were associated with immunohistochemical and genetic alterations in the overlying tumor cells, including the loss of estrogen receptor expression, a higher frequency of loss of heterozygosity, and a higher expression of cell cycle, angiogenesis, and invasion-related genes. Focal ME layer disruptions were also associated with a higher rate of epithelial proliferation and leukocyte infiltration. We propose the novel hypothesis that a localized death of ME cells and immunoreactions that accompany an external environmental insult or internal genetic alterations are triggering factors for ME layer disruptions, basement membrane degradation, and subsequent tumor progression and invasion.     

Molecular and structural analysis of C4-specific PEPC isoform from Pennisetum glaucum plays a role in stress adaptation

As an activator of adenylate cyclase, the neuropeptide Pituitary Adenylate Cyclase Activating Peptide (PACAP) impacts levels of cyclic AMP, a key second messenger available in brain cells. PACAP is involved in certain adult behaviors. To elucidate PACAP interactions, a compendium of microarrays representing mRNA expression in the adult mouse whole brain was pooled from the Phenogen database for analysis. A regulatory network was computed based on mutual information between gene pairs using gene expression data across the compendium. Clusters among genes directly linked to PACAP, and probable interactions between corresponding proteins were computed. Database “experts” affirmed some of the inferred relationships. The findings suggest ADCY7 is probably the adenylate cyclase isoform most relevant to PACAP's action. They also support intervening roles for kinases including GSK3B, PI 3-kinase, SGK3 and AMPK. Other high-confidence interactions are hypothesized for future testing. This new information has implications for certain behavioral and other disorders.     

Topology and sequence in the folding of a TIM barrel protein: global analysis highlights partitioning between transient off-pathway and stable on-pathway folding intermediates in the complex folding mechanism of a (betaalpha)8 barrel of unknown function from B. subtilis

The relative contributions of chain topology and amino acid sequence in directing the folding of a (betaalpha)(8) TIM barrel protein of unknown function encoded by the Bacillus subtilis iolI gene (IOLI) were assessed by reversible urea denaturation and a combination of circular dichroism, fluorescence and time-resolved fluorescence anisotropy spectroscopy. The equilibrium reaction for IOLI involves, in addition to the native and unfolded species, a stable intermediate with significant secondary structure and stability and self-associated forms of both the native and intermediate states. Global kinetic analysis revealed that the unfolded state partitions between an off-pathway refolding intermediate and the on-pathway equilibrium intermediate early in folding. Comparisons with the folding mechanisms of two other TIM barrel proteins, indole-3-glycerol phosphate synthase from the thermophile Sulfolobus solfataricus (sIGPS) and the alpha subunit of Escherichia coli tryptophan synthase (alphaTS), reveal striking similarities that argue for a dominant role of the topology in both early and late events in folding. Sequence-specific effects are apparent in the magnitudes of the relaxation times and relative stabilities, in the presence of additional monomeric folding intermediates for alphaTS and sIGPS and in rate-limiting proline isomerization reactions for alphaTS.