婴儿与母亲皮肤细菌群落结构的比较分析

为探索母婴皮肤细菌群落特征,本研究对8对母婴7个不同皮肤部位的细菌群落进行焦磷酸测序分析。结果显示,皮肤细菌主要属于放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)。总体而言,母婴皮肤细菌群落的组成相似,但丰度存在差异。母亲皮肤表面的丙酸杆菌属(Propionibacterium)丰度显著高于婴儿(P<0.05)。在婴儿皮肤表面,链球菌属(Streptococcus)和葡萄球菌属(Staphylococcus)最丰富;剖宫产出生的婴儿额头表面葡萄球菌属的丰度显著高于自然分娩出生的婴儿(P<0.05)。婴儿皮肤表面特有的常驻菌属包括孪生球菌属(Gemella)、普雷沃菌属(Prevotella)、罗思菌属(Rothia)和韦荣球菌属(Veillonella)与成人常见的口腔细菌一致,表明母亲的口腔细菌对婴儿早期皮肤微生态有一定的塑造作用。婴儿皮肤表面的细菌种类与自己母亲相近,各细菌的含量则与其他婴儿相近。母亲皮脂溢出部位(额头和背部)的细菌多样性较其他部位低,且皮肤潮湿、干燥、脂溢部位之间细菌群落差异较大;而婴儿背部细菌群落与肘窝相似,额头与手背相似。     

Acquisition and transfer of visual Go/No-go discrimination by a chimpanzee

An adolescent female chimpanzee was trained to press a key in the presence of a computer-graphic geometric figure (“Go” stimulus) within 5 sec and not to press the key during 5-sec presentations of another figure (“No-go” stimulus) with food reinforcement. In the acquisition training, the accuracy of performance increased primarily as a result of learning to inhibit key presses in No-go trials. The chimpanzee acquired this “Go/No-go” visual discrimination task in 1,260 trials. She was then given 14 successive transfer problems. The results for these problems suggested that learning-set formation and repeated use of the same discriminative stimuli both influenced transfer to new problems.     

How rhesus monkey infants budget their time between mothers and peers

Social play between two rhesus monkey (Macaca mulatta) infants takes place mainly when they are both not in body contact with their mothers. This suggests that social play and mother-infant body contact are potential competitors in the infants' time budgets. We investigated whether the presence of a playmate changed the duration of mother-infant body contact during the first 6 months of life. A decrease in contact would favour play opportunity. Mother-infant pairs were observed alternately alone and together with another pair. Resting, which always occurs during on-mother, was not reduced in the presence of a peer. Body contact during activity phases was reduced in most playing pairs, but only to a large extent in pairs which showed relatively high levels of contact in the situation without a peer. Play opportunity was further increased by synchronization of the rest-activity cycles of the two infants; this occurred without a reduction in mother-infant interactions. No influences by mothers on play opportunity were demonstrated, except that strong maternal interference with resting reduced activity synchronization.     

Longitudinal comparison of the developing gut virome in infants and their mothers

1. Download : Download high-res image (190KB)
2. Download : Download full-size image

     

A case of offspring desertion by a female chimpanzee and the behavioral changes of the abandoned offspring

In the Mahale Mountains National Park, Tanzania, a chimpanzee mother moved to a neighboring unit-group leaving her 5-year-old son behind in the original group. The mother remained in the new group for ten months and then after conceiving, returned to the original group. The mother and son were reunited again but the son died of illness two months later. The mother gave birth to a baby in the original group but eventually transferred to the neighboring group after that baby disappeared. This is the first record of an immature chimpanzee abandoned by its emigrating mother, although a similar phenomenon has been reported for gorillas and Hanuman langurs. The abandoned offspring followed an adult male of the unit-group and the male was the individual who gave most of the care to the offspring. The offspring's time spent on grooming others increased, the time spent on being groomed decreased, and the rate of aggression toward him increased after his mother's desertion. This report will occasion to reconsider the previous notion of all-powerful mother-offspring bond in chimpanzees.     

Baby-transfer and other interactions between its mother and grandmother in a captive social group of lowland gorillas

This report describes the responses of an experienced gorilla mother to inappropriate maternal behavior displayed by her young adult daughter toward a newborn baby and repeated acts of baby-transfer between these two females in a captive social group of lowland gorillas (Gorilla g. gorilla). The quality of infant care by the young adult daughter clearly improved during the first 4 days after birth, and this improvement was at least partly based on her mothers encouragement. Thus, the mothers activities can be considered scaffolding for her daughter with regard to maternal infant care.     

Food transfer between mother and infant chimpanzees of the Mahale Mountains National Park,Tanzania

We studied food transfer between chimpanzee mothers and infants in the Mahale Mountains National Park, Tanzania. The rate of infant solicitation for food dramatically increased in the second year of life, then gradually decreased and, in the seventh year, virtually disappeared. The pattern of the ontogeny of food sharing precisely followed that of solicitation because mothers shared food only when requested to do so by their infants. The success rate of solicitation, however, did not display extreme changes across ages. Food that was difficult to process was shared more frequently because it was more likely to be demanded by infants. We defined food retrieval as an infant’s recovery of leftovers discarded by its mother. Food types retrieved were often those that are difficult to process and were also likely to be shared by mothers. However, infants tended to solicit small, difficult food types for sharing while they often retrieved the remains of large, difficult food types. The function of food sharing and food retrieval lies in an infant’s learning food types that it cannot easily obtain or process by itself. The level of competition for food between mothers and infants remained low throughout infancy. We noted no particular characteristic about foods from which infants were displaced by mothers. As infants grew older, they increased the distance between themselves and mothers that became more aggressive.     

Nutrient transfer supports a beneficial relationship between the canopy ant,Azteca trigona,and its host tree

1. Energy fluxes between ants and plants have been a focal point for documenting mutualistic behaviour. Plants can provide resources to ants through the production of extrafloral nectaries. In exchange, ants can fertilise plants through their nutrient‐ and microbe‐rich refuse. 2. Here, we test a potential facultative mutualism between the carton‐nesting canopy ant, Azteca trigona, and their host trees. Through observational and experimental approaches, this study documents how nutrient transfer provides a basis for this beneficial ant–plant relationship. 3. In a greenhouse experiment, fertilisation with sterilised refuse (i.e. nutrients only) increased seedling growth three‐fold, while the refuse with its natural microbial community increased growth 11‐fold. 4. Total root density was doubled in refuse piles compared with the surrounding area in situ. On average, refuse provides host trees and the surrounding plant community with access to a > 800% increase in N, P and K relative to leaf litter. 5. Azteca trigona preferentially nests in trees with extrafloral nectaries and on large, longer‐lived tree species. 6. Given the nutrient‐poor nature of the Neotropics, host trees probably experience significant benefits from refuse fertilisation. Conversely, A. trigona benefit from long‐term stable structural support for nests and access to nutrient‐rich extrafloral nectaries. Without clear costs to either A. trigona or host trees, it is proposed that these positive interactions are preliminary evidence of a facultative mutualism.     

comparison between the complete mitochondrial DNA sequences ofHomo and the common chimpanzee based on nonchimeric sequences

The complete mitochondrial DNA (mtDNA) molecules ofHomo and of the common chimpanzee were sequenced. Each sequence was established from tissue of one individual and thus nonchimeric. Both sequences were assembled in their entirety from natural (not PCR amplified) clones. Comparison with sequences in the literature identified the chimpanzee specimen asPan troglodytes verus, the West African variety of the species. The nucleotide difference between the complete human and chimpanzee sequences is 8.9%. The difference between the control regions of the two sequences is 13.9% and that between the remaining portions of the sequences 8.5%. The mean amino acid difference between the inferred products of the 13 peptide-coding genes is 4.4%. Sequences of the complete control regions, the complete 12S rRNA genes, the complete cytochromeb genes, and portions of the NADH4 and NADH5 genes of two other chimpanzee specimens showed that they were similar but strikingly different from the same regions of the completely sequenced molecule fromPan troglodytes verus. The two specimens were identified asPan troglodytes troglodytes, the Central African variety of the common chimpanzee.     

Food access in captive Ammotragus: the role played by hierarchy and mother–infant interactions

An analysis of individuals' behavior when accessing a restricted food source (troughs) was carried out in a captive population of aoudad (Ammotragus lervia). Access to the troughs followed a strict hierarchical order, as higher‐ranking individuals fed before lower‐ranking ones. Unweaned male and female calves made use of the troughs from the ages of 2 and 3 months, respectively. Both fed from the troughs more frequently and for longer periods when their mother was present, which allowed them to make use of the troughs while skipping the hierarchical order. Calves received fewer threats when in proximity to their mothers, particularly in high‐ranking families. Mothers defended their calves from other herdmates more frequently when at the feeding area than in other areas of the herd. However, only sated mothers let their calves feed freely from the troughs; unsated mothers showed an aggressive behavior even toward their calves. I conclude that a maternal presence is necessary for aoudad calves to successfully feed from troughs, and that families of higher social rank benefit by getting access to this food source earlier in the day and are disturbed less than low‐ranking families. Zoo Biol 21:597–605, 2002. © 2002 Wiley‐Liss, Inc.     

How rhesus monkey mothers and infants keep in touch when infants are at risk from social companions

Ten-to 17-week-old rhesus monkey infants that received hits from companions other than their mother at high rates (relative to their rates of involvement in playful social encounters with those companions) tended to be members of mother-infant dyads that were vigilant. Criteria of vigilance were frequent contacts between mother and infant during the first 5 sec of the infants’ social encounters and/or a bias of mother-infant contacts toward that time. Infants that received few hits per encounter came from both vigilant and nonvigilant dyads. When analyzed alone, mothers’ rates showed the same trends. High levels of vigilance tended to reduce infants’rates of making social contacts. Maternal social rank and other measures of the infants’ social involvement were not correlated with vigilance. There is no evidence that mothers and infants were in conflict with each other about interrupting the infants’ encounters. Understanding vigilance becomes important whenever vigilant activity conflicts with other activities. Special problems arise because decisions about vigilance levels require judgments of risk based on the kinds of events that occur only rarely if vigilance is effective. A model providing a framework for studies of vigilance against the risks of infants’ social activities was developed. It recognizes that (1) risk-reducing vigilant behavior can conflict with acquiring information about risk; (2) in social situations where reliable estimates of risk are impossible, individuals might follow rules of thumb (e.g., be restrictive) rather than modify behavior moment by moment according to the current situation;and (3) at the dyad’s optimum balance between vigilance for the current infant and investment in subsequent off-spring, the infant will not be totally protected, so that while dyads at higher risks are more vigilant, the risks are also realized to a greater extent (e.g., itin terms of the number of hits received per encounter).     

Mass transfer efficiency between harp seal (Phoca groenlandica) mothers and their pups during lactation

We investigated the efficiency of mass transfer in lactating harp seals through serial measurements on individual mother-pup pairs during the whelping seasons of 1988 and 1989. We also compared the influence of longitudinal versus cross-sectional sampling on estimates of the efficiency of mass transfer. Among longitudinally sampled pairs, pups grew at an average rate of 2·3 ± 0·5 (mean ± S.D.) kg/d (N = 20). The concomitant mass loss by females averaged 3·1 ± 0·8 kg/d (N = 19). The mean efficiency of mass transfer was 77·0 ± 13·6% (N= 19 pairs).
Estimates of pup growth and female mass loss from regressions of cross-sectional data were 2·0 kg/d and 3·1 kg/d, respectively. These values produce an estimate of 65% for the efficiency of mass transfer.
Consistent with the high efficiency of mass transfer, harp seal females contribute less of their total body mass to nursing ( c. 28%) than most other phocids examined. The resulting energy savings may be important for females of an ice-breeding species, which migrate a long distance shortly after weaning their pups     

Food transfer in common marmosets: parents change their tolerance depending on the age of offspring

Food transfer is considered to provide infants with additional nutrients during weaning, and in fact, its frequency peaks around this time. However, the mechanisms underlying such food transfer remain unclear. In this study, we investigated whether adult common marmosets (Callithrix jacchus) change their tolerance to offspring begging for food depending on the offspring's age. We used four families consisting of breeding pairs, older offspring (29-49 weeks old), and younger offspring (7-15 weeks old). To directly compare the responses of a parent with its older and younger offspring, we placed one parent and one offspring in a testing space at one time. We presented foods where only the parent could reach them to ensure that the foods were transferred from the parent to offspring. Younger offspring showed more interest in food being held by the parents than older offspring. Parents refused older offspring more frequently than younger offspring and transferred food more often to younger offspring than to older offspring. There was no difference in all behavioral categories between fathers and mothers. These results suggest that both fathers and mothers are more tolerant to weanlings, but their tolerance decreases as offspring mature.     

青海门源地区大(狂鸟)和雕鸮的食性比较

1999～2002年的6～8月份,在青海门源地区收集了大(狂鸟)和雕鸮的吐弃块(pellets)和残留食物(food remains),带回实验室进行分检鉴定、研究分析.大(狂鸟)食物中共有736个猎物,其中高原鼢鼠28只、高原鼠兔139只、甘肃鼠兔142只、田鼠科动物422只、雀形目鸟类4只、香鼬1只;各猎物对大(狂鸟)食物的生物量贡献率分别为14.26%、40.79%、17.39%、26.99%、0.22%、0.35%.雕鸮食物中共有330个猎物,其中高原鼢鼠17只、高原鼠兔77只、甘肃鼠兔44只、田鼠科动物183只、雀形目鸟类2只、红脚鹬2只、高原兔5只;各猎物对雕鸮食物的生物量贡献率分别为11.83%、30.87%、7.36%、16.00%、0.15%、0.62%、33.17%.雕鸮的食物生态位宽度与大(狂鸟)的食物生态位宽度相近,食物生态位高度重叠,但是它们捕食同种猎物的比例显著不同.     

Energy transfer rate and electron–phonon coupling properties in Eu3+‐doped nanophosphors

A series of controllable emissions SrWO₄:Eu³⁺ and charge‐compensated SrWO₄: (m = 0.01 or 0.20) phosphors was successfully prepared via a simple co‐precipitation method. The energy transfer mechanism was studied based on the Huang's theory. A low magnitude of Huang‐Rhys factor (10^?2) was calculated using phonon sideband spectra. The Judd–Ofelt parameters Ω_λ (λ = 2, 4 and 6) of Eu³⁺‐activated SrWO₄ doped with charge compensation were obtained. The calculated Commission Internationale de l'Eclairage chromaticity coordinates were found to be about (0.67, 0.33) for SrWO₄: and charge‐compensated SrWO₄: phosphors, which coincided with the National Television Standard Committee system standard values for red. A white light emission was obtained under 362 nm excitation. The correlated color temperature was computed by a simple equation to characterize light sources. Thus, warm white light‐emitting diodes with higher Ra can be constructed by combining as‐prepared high efficiency, low correlated color temperature and high color purity phosphor.     

Maternal effects in Daphnia: what mothers are telling their offspring and do they listen?

Maternal effects can significantly impact offspring performance. Provisioning of offspring with energy stores can quantitatively alter their growth rates, survivorship, and future fecundity, and influence population regulatory mechanisms. In this paper, we show that maternal effects can also qualitatively affect offspring reproduction (i.e. their mode of reproduction). The freshwater herbivore Daphnia pulex can change the amount of energy allocated between asexual and ephippial egg production. Our experiments on individuals, experiencing “step‐up” or “step‐down” food manipulations, reveal that offspring qualitatively shift their energy allocation away from asexual reproduction to ephippial egg production when there is a simple mismatch between maternal and offspring food environments. We show that the response is asymmetric with respect to changes in food level, ephippial egg production is higher with a greater mismatch between environments, and that the effect can be observed in dynamic experimental populations. These results point to a “generational memory” that could challenge our interpretation of field patterns and mechanisms influencing population dynamics in Daphnia–algal systems.