On the mystery of the golden angle in phyllotaxis

Phyllotaxis, the arrangement of leaves around a stem, shows in the vast majority of cases a regularity in the divergence angle of subsequent leaves which divide the whole circle into regular fractions. These are in most cases rational fractions of two Fibonacci numbers in an alternating series, converging towards the irrational limit of the golden section, corresponding to the golden divergence angle of 137.5 . . . degrees. This peculiarity was a long‐standing mystery. Here, it is related to the evolutionary pressure of optimal light capture for maximal photosynthetic activity. A model is established which relates minimal shadowing for the lower leaves to the divergence angle. Numerical results of this model agree well with semi‐empirical data on the dependence of light capture from the divergence angle. The basic shadow function of the model is also related with the demand of minimal shadowing for the angular separation of leaves and obtain, using elementary number theory, as solution the golden section. Further numerical studies show that the rational approach to the golden section (Schimper–Braun series) is related to the leaf width and the number of leaves of the plant.     

Availability of optimal‐sized prey affects global distribution patterns of the golden eagle Aquila chrysaetos

Climate and landscape change are expected to significantly affect trophic interactions, which will especially harm top predators such as the golden eagle Aquila chrysaetos. Availability of optimal prey is recognized to influence reproductive success of raptors on a regional scale. For the golden eagle, medium‐sized prey species between 0.5 and 5 kg are widely considered to be optimal prey during the breeding season, whereas smaller and larger species are deemed as energetically sub‐optimal. However, knowledge about the effects of optimal prey availability is still scarce on larger scales. To decrease this apparent knowledge gap, we combined biogeographical information on range margins with information about the foraging behaviour and reproductive success of golden eagles from 67 studies spanning the Northern Hemisphere. We hypothesized that availability of optimal prey will affect foraging behaviour and breeding success and, thus, distribution patterns of the golden eagle not only on a local but also on a continental scale. We correlated the diet breadth quantifying foraging generalism, breeding success and proportions of small (< 0.5 kg), medium (0.5–5 kg) and large‐sized (> 5 kg) prey species within the diet with the minimum distance of the examined eagles to the actual species distribution boundary. Closer to the range edge, we observed decreased proportions of medium‐sized prey species and decreasing breeding success of golden eagles. Diet breadth as well as proportions of small and large‐sized prey species increased, however, towards the range edge. Thus, availability of optimal‐sized prey species seems to be a crucial driver of foraging behaviour, breeding success and distribution of golden eagles on a continental scale. However, underlying effects of landscape characteristics and human influence on optimal prey availability has to be investigated in further large‐scale studies to fully understand the major threats facing the golden eagle and possibly other large terrestrial birds of prey.     

剖腹产建立SPF金黄地鼠种群

为了规范我国实验动物管理,尽快提高实验动物质量,真正落实2000年版生物制品规程,同时也为了提高我国乙型脑炎活疫苗的质量,使其尽快进入国际市场,作者利用普通金黄地鼠,采用剖腹产手术,以德国SPF金黄地鼠代乳,率先在国内培育出了自己的SPF金黄地鼠种群,自检和送检结果表明,该种群质量符合国家SPF金黄地鼠质量标准。     

A History of the Study of Phyllotaxis

The study of the patterns formed by similar units in plants(e.g. leaves, scales, florets) is traced from the first primitiveobservations in ancient times to the sophisticated studies oftoday. Mathematics entered into the study early, at first asa way of describing the patterns observed, with Fibonacci numbersand the golden section playing a major role, and later in theconstruction of models designed to explain their origin. Observationand experiment alternated with theory. Explanations offeredalternated between functional and causal. Functional explanationsthat were at first teleological gave way to those based on theidea of natural selection. Causal explanations alternated betweenthe chemical and the mechanical. New light has been cast onthe subject with the realization that phenomena similar to phyllotaxisoccur in realms outside of botany. Phyllotaxis; genes; algae; comparative morphology; evolutionary theory; systems research; optimal design; polypeptide chains; living crystals; allometry     

双歧杆菌表达ETEC CFA／I的免疫电镜定位分析

目的研究双歧杆菌表达的CFA／I在细胞中的分布。方法将培养8～10h的重组双歧杆菌固定后制作电镜切片，镜检合格后用镍网捞取3-5个切片与金标抗体作用，镜检CFA／I在双歧杆菌中的表达分布。结果自制的胶体金颗粒均匀，与抗体结合后能够示踪CFA／I在双歧杆菌中的表达分布。结论双歧杆菌表达的CFA／I主要集中在靠近细胞膜的周质腔一侧，利于向外分泌和释放。     

The occurrence of "skein bones" in the enchondral layer of the bony labyrinth capsule

Skein bone which is typical in enchondral layer of human bony otic capsule also is found in pig, rabbit, guinea pig, rat, mouse and golden hamster. This structural principle of enchondral layer of bony otic capsule is discussed.     

Nestling sex ratio of golden‐winged warblers Vermivora chrysoptera in an introgressed population

Sex ratio biases in avian species remain controversial, although several studies have documented apparent facultative adjustment of offspring sex ratios. While hybridizing pied and collared flycatchers have exhibited sex ratio skews that may be a response to sex‐based costs associated with hybridization, this appears not to be true of a hybridized population of blue‐winged Vermivora pinus and golden‐winged V. chrysoptera warblers. We examined the primary sex ratio of nestlings in a population of hybrid and introgressed golden‐winged warblers. The sex ratio of 298 nestlings from 81 nests in the population was approximately 50:50. We conducted paternity assignments and analyzed groups of nestlings with shared genetic parents (“genetic broods”) and found no difference from the expected binomial distribution, and no statistically significant relationship between parental species phenotype and nestling sex ratio. We saw no evidence of preferential production of male or female nestlings, and female hybrids were found to mate and breed in the population. This suggests that heterogametic (female) hybrids are both viable and fertile, and thus that Haldane's Rule does not apply to this system. While populations of hybridizing golden‐winged warblers should be monitored for evidence of costs of heterospecific pairings, it is unlikely that adjustment of sex ratios would be the form of compensation for sub‐optimal mating conditions. Our results provide support for the emerging hypothesis that hybrids suffer no disadvantage relative to golden‐winged and blue‐winged warblers.     

The principle of complementarity in the design of reserve networks to conserve biodiversity: A preliminary history

Explicit, quantitative procedures for identifying biodiversity priority areas are replacing the often ad hoc procedures used in the past to design networks of reserves to conserve biodiversity. This change facilitates more informed choices by policy makers, and thereby makes possible greater satisfaction of conservation goals with increased efficiency. A key feature of these procedures is the use of the principle of complementarity, which ensures that areas chosen for inclusion in a reserve network complement those already selected. This paper sketches the historical development of the principle of complementarity and its applications in practical policy decisions. In the first section a brief account is given of the circumstances out of which concerns for more explicit systematic methods for the assessment of the conservation value of different areas arose. The second section details the emergence of the principle of complementarity in four independent contexts. The third section consists of case studies of the use of the principle of complementarity to make practical policy decisions in Australasia, Africa, and America. In the last section, an assessment is made of the extent to which the principle of complementarity transformed the practice of conservation biology by introducing new standards of rigor and explicitness.     

金叶马褂木叶片特性及其 RAPD 分子鉴定

金叶马褂木是从当地金边马褂木中发现的春季至初夏间全叶呈金黄色至淡黄色的芽变材料。对该芽变种质的叶片特性进行了连续8年的观察与调查,同时结合RAPD技术进行了初步的分子鉴定。叶片特性观察与调查结果表明,金叶马褂木叶片大小与金边马褂木、北美马褂木差异不大,但叶片叶绿素含量显著少于金边马褂木和北美马褂木,叶片色泽也与金边马褂木有显著性差异。结合RAPD分子鉴定结果,认为金叶马褂木是一个发生变异的新种质。     

Fibonacci,quasicrystals and the beauty of flowers

The appearance of Fibonacci sequences and the golden ratio in plant structures is one of the great outstanding puzzles of biology. Here I suggest that quasicrystals, which naturally pack in the golden ratio, may be ubiquitous in biological systems and introduce the golden ratio into plant phyllotaxy. The appearance of golden ratio-based structures as beautiful indicates that the golden ratio may play a role in the development of consciousness and lead to the aesthetic natural selection of flowering plants.     

Maternal and fetal outcome in elective versus emergency caesarean section in a developing country

As the other major European countries, Croatia has also seen a marked increase in the rate of caesarean sections. The aim of this study was to determine the most common reasons for caesarean section, to compare emergency and elective caesarean section in regard to intraoperative and postoperative complications in both mother and child, and to assess the decision-to-delivery interval (DDI) in our clinic in comparison to current recommendations. Analyzing the results of our research we can say that the new-borns in the group with the elective caesarean section had considerably better Apgar index score in the first minute (p = 0.00056) and in the fifth minute (p = 0.054) than the children born in the group with emergency caesarean section. Children from the group with elective caesarean section had also less frequent asphyxia (p = 0.02315) and considerably less frequent resuscitation (p = 0.0143) than the children from the group with emergency caesarean sections. Only 39.73% of the emergency caesarean sections were performed within the "golden standard" period of 30 minutes. Regarding the data from the literature our results are similar with the ones from developed countries and 30 minute current standard seem to be not achievable.     

基于“金课”背景的生物化学翻转课堂教学

为了提升混合式教学质量,教育部提出建设6 000门线上线下混合式"金课"。翻转课堂是衔接线上线下混合式教学的重要纽带,它颠覆了传统课堂教学中"老师讲→学生听"的模式,体现了以"学生为中心"的教学理念。根据"金课"建设标准,生物化学混合式教学通过重新建构翻转课堂教学模式,综合设计与分层教学,努力解决生物化学课程教学中的短板、瓶颈、关键问题,真正提升学生自主建构意识和信息处理能力,让学生在思辨与探讨中深度学习,建构适合自己的更完善的专业知识框架。     

The rise and fall of handicap principle: a commentary on the “Modelling and the fall and rise of the handicap principle”

The honesty of animal communication is in the spot lights in the last 30 years. During most of this time the field was dominated by one explanation: Zahavi’s handicap principle (Zahavi, J Theor Biol 67:603–605, 1975; Grafen, J Theor Biol 144:517–546, 1990). Grose (Biol Philos 2011) embarks to explain both the success of the theory and the empirical difficulties that exist despite this success. While I wholeheartedly agree with the criticism offered by Grose and with almost all the claims he makes, the treatment of the issue is far from complete and it still leaves much to be explained. Accordingly, my commentary consist of six sections: in the first section I clear up some technical issues left unexposed, most importantly the role of strategic cost in handicap signalling; in the second section I relate this to empirical testing; in the next section I comment on the historical development of the handicap principle; in the fourth section I review the biological models that came up with conclusions that contradict the handicap principle; in the fifth section I discuss the reasons behind the success of the handicap theory; finally, in the last section I discuss the application of the handicap theory to anthropology and human sciences.     

南丹金线兰的植物形态和显微鉴定

采用生药学显微鉴定方法研究南丹金线兰(Anoectochilus nandanensis)的原植物形态、组织构造及粉末显微特征。南丹金线兰叶片呈卵形或卵状披针形,具金红色叶脉,花不倒置;唇瓣白色,呈Y字形,前部明显扩大并2裂,裂片狭长圆形,中部收狭,其两侧呈向下的细齿状或角片状,两侧白色细齿各4～5条。显微结构中,根、茎横切面中皮层明显,具草酸钙针晶、粘液细胞等;叶横切面上表皮细胞形状为乳突状突起。粉末中可见草酸钙针晶和导管。这些特征可为南丹金线兰的生药鉴别和资源开发利用提供参考依据。     

Hexahedral modular bioreactor for solid state bioprocesses

The design of a modular bioreactor for solid state fermentation is a promising development because it keeps the homogeneity of the bed at optimal levels. This study determines the optimum geometry of elementary modules of hexahedral bioreactors subjected to constant volume. The bioreactors have a square section and do not need an external cooling system, because the optimization limits the temperature of the bed to 35°C. The geometric optimization followed the Constructal principle of minimum heat resistance. The numerical simulations take into account the following parameters: inlet air temperature and velocity, and module volume. Once the elementary module has been selected, the total volume of the bioreactor can be calculated.     

川金丝猴血象和血液生物化学指标的研究

测定了１２只川金丝猴的血象和血液生物化学指标。结果发现;在各项血象指标中,只有白细胞总数和白细胞分类计数与滇金丝猴的有较大判别;在各项生物化学指标中,血清尿酸含量比滇金猴的高,血清总胆固醇和尿素氮的含量比滇金丝猴的低,血清白收白和球蛋白比值与人的差异明显;其余各项指标与滇金丝猴和人的十分接近。     

Study on the interaction between nucleic acids and acetamiprid

The interaction between deoxyribonucleic acid (DNA) and acetamiprid was studied. It was found that the fluorescence of acetamiprid could be enhanced in the presence of DNA in sulfuric acid solution. The excitation and emission wavelength of acetamiprid was 291 nm and 587 nm, respectively. Under optimal conditions, the calibration graph is over the range of 0.1-10 micromL(-1). The calibration limit is 0.06 microg mL(-1) (S/N = 3). The determination results of DNA in yeast cell and golden staphylococcus samples by this method were satisfactory. The mechanism of the reaction is discussed.     

Biogenic aldehyde(s) derived from the action of monoamine oxidase may mediate the antidipsotropic effect of daidzin

Daidzin, a major active principle of an ancient herbal treatment for 'alcohol addiction', was first shown to suppress ethanol intake in Syrian golden hamsters. Since then this activity has been confirmed in Wistar rats, Fawn hooded rats, genetically bred alcohol preferring P rats and African green moneys under various experimental conditions, including two-level operant, two-bottle free-choice, limited access, and alcohol-deprivation paradigms. In vitro, daidzin is a potent and selective inhibitor of mitochondrial aldehyde dehydrogenase (ALDH-2). However, in vivo, it does not affect overall acetaldehyde metabolism in golden hamsters. Using isolated hamster liver mitochondria and 5-hydroxytryptamine (5-HT) and dopamine (DA) as the substrates, we demonstrated that daidzin inhibits the second but not the first step of the MAO/ALDH-2 pathway, the major pathway that catalyzes monoamine metabolism in mitochondria. Correlation studies using structural analogs of daidzin led to the hypothesis that the mitochondrial MAO/ALDH-2 pathway may be the site of action of daidzin and that one or more biogenic aldehydes such as 5-hydroxyindole-3-acetaldehyde (5-HIAL) and/or DOPAL derived from the action of monoamine oxidase (MAO) may be mediators of its antidipsotropic action.     

Biogenic aldehyde(s) derived from the action of monoamine oxidase may mediate the antidipsotropic effect of daidzin

Daidzin, a major active principle of an ancient herbal treatment for ‘alcohol addiction’, was first shown to suppress ethanol intake in Syrian golden hamsters. Since then this activity has been confirmed in Wistar rats, Fawn hooded rats, genetically bred alcohol preferring P rats and African green moneys under various experimental conditions, including two-level operant, two-bottle free-choice, limited access, and alcohol-deprivation paradigms. In vitro, daidzin is a potent and selective inhibitor of mitochondrial aldehyde dehydrogenase (ALDH-2). However, in vivo, it does not affect overall acetaldehyde metabolism in golden hamsters. Using isolated hamster liver mitochondria and 5-hydroxytryptamine (5-HT) and dopamine (DA) as the substrates, we demonstrated that daidzin inhibits the second but not the first step of the MAO/ALDH-2 pathway, the major pathway that catalyzes monoamine metabolism in mitochondria. Correlation studies using structural analogs of daidzin led to the hypothesis that the mitochondrial MAO/ALDH-2 pathway may be the site of action of daidzin and that one or more biogenic aldehydes such as 5-hydroxyindole-3-acetaldehyde (5-HIAL) and/or DOPAL derived from the action of monoamine oxidase (MAO) may be mediators of its antidipsotropic action.