基于创新能力培养的“微生物学”研究型教学模式探索

微生物学是生命科学的重要组成部分。随着科学技术的飞速发展,微生物学教学内容和教学方法都需要不断革新,以满足高素质人才培养的需求。华中农业大学在微生物学教学过程中积极开展基于创新能力培养的教学改革实践,课堂上通过推崇学科名人,弘扬科学精神;关注社会焦点,激发学习兴趣;引入学科前沿,培养创新意识等积极引导学生学习微生物学相关知识。通过翻转课堂、对分课堂,借助"微助教"微信公众平台等改变传统的教学模式与师生互动的方式,突破学生学习的时空局限,加强师生交流。依托农业微生物学国家重点实验室等高水平的科研平台,鼓励学生进入实验室运用微生物学知识开展科研实践,引导学生参加各类竞赛,实现理论知识学习向实践创新能力的转化。总之,学生不仅能够在"微生物学"课堂上牢固地掌握微生物学知识,创新思维也得到锻炼,创新能力显著增强。     

The wing base of the palaeodictyopteran genus Dunbaria Tillyard: Where are we now?

The structure of insect wing articulation is considered as reliable source of high level characters for phylogenetic analyses. However, the correct identification of homologous structures among the main groups of Pterygota is a hotly debated issue. Therefore, the reconstruction of the wing bases in Paleozoic extinct relatives is of great interest, but at the same time it should be treated with extreme caution due to distortions caused by taphonomic effects. The present study is focused on the wing base in Dunbaria (Spilapteridae). The articulation in Dunbaria quinquefasciata is mainly formed by a prominent upright axillary plate while the humeral plate is markedly reduced. Due to unique preservation of surface relief of the axillary plate, its composition shows a detailed pattern of three fused axillary sclerites and presumable position of the sclerite 3Ax. The obtained structures were compared among Spilapteridae and to other palaeodictyopterans Ostrava nigra (Homoiopteridae) and Namuroningxia elegans (Namuroningxiidae). The comparative study uncovered two patterns of 3Ax in Dunbaria and Namuroningxia, which correspond to their different suprafamilial classification. In contrast to previous studies these new results reveal the homologous structural elements in the wing base between Paleozoic Palaeodictyoptera and their extant relatives of Ephemeroptera, Odonata and Neoptera.     

Macroevolution in progress: competition between semislugs and slugs resulting in ecological displacement and ecological release

The vitrinids, which represent a probably competitively inferior transitional stage between shelled snails and slugs, and their sister group, the limacoid slugs, are used to investigate a macroevolutionary effect of a microevolutionary process, competition between individuals resulting in ecological displacement of one clade by another, based on patterns in the present-day world. The activity period and the altitudinal distribution of the vitrinids has shifted - to the cold season or to higher altitudes, respectively - in those regions where their range overlaps with that of the limacoid slugs. The diversity of the vitrinids is lower in regions with limacoid slugs. These patterns can be ascribed to the ecological displacement or the exclusion of the vitrinids from some habitats by limacoid slugs. Two vitrinid clades which independently colonized regions without limacoid slugs show patterns attributable to ecological release. The ecological displacement or exclusion of the vitrinids by the slugs is probably due to competition for shelter.     

The coevolution of innovation and technical intelligence in primates

In birds and primates, the frequency of behavioural innovation has been shown to covary with absolute and relative brain size, leading to the suggestion that large brains allow animals to innovate, and/or that selection for innovativeness, together with social learning, may have driven brain enlargement. We examined the relationship between primate brain size and both technical (i.e. tool using) and non-technical innovation, deploying a combination of phylogenetically informed regression and exploratory causal graph analyses. Regression analyses revealed that absolute and relative brain size correlated positively with technical innovation, and exhibited consistently weaker, but still positive, relationships with non-technical innovation. These findings mirror similar results in birds. Our exploratory causal graph analyses suggested that technical innovation shares strong direct relationships with brain size, body size, social learning rate and social group size, whereas non-technical innovation did not exhibit a direct relationship with brain size. Nonetheless, non-technical innovation was linked to brain size indirectly via diet and life-history variables. Our findings support ‘technical intelligence’ hypotheses in linking technical innovation to encephalization in the restricted set of primate lineages where technical innovation has been reported. Our findings also provide support for a broad co-evolving complex of brain, behaviour, life-history, social and dietary variables, providing secondary support for social and ecological intelligence hypotheses. The ability to gain access to difficult-to-extract, but potentially nutrient-rich, resources through tool use may have conferred on some primates adaptive advantages, leading to selection for brain circuitry that underlies technical proficiency.     

Individual differences in children's innovative problem-solving are not predicted by divergent thinking or executive functions

Recent studies of children''s tool innovation have revealed that there is variation in children''s success in middle-childhood. In two individual differences studies, we sought to identify personal characteristics that might predict success on an innovation task. In Study 1, we found that although measures of divergent thinking were related to each other they did not predict innovation success. In Study 2, we measured executive functioning including: inhibition, working memory, attentional flexibility and ill-structured problem-solving. None of these measures predicted innovation, but, innovation was predicted by children''s performance on a receptive vocabulary scale that may function as a proxy for general intelligence. We did not find evidence that children''s innovation was predicted by specific personal characteristics.     

Light enough to travel or wise enough to stay? Brain size evolution and migratory behavior in birds

Brain size relative to body size is smaller in migratory than in nonmigratory birds. Two mutually nonexclusive hypotheses had been proposed to explain this association. On the one hand, the “energetic trade‐off hypothesis” claims that migratory species were selected to have smaller brains because of the interplay between neural tissue volume and migratory flight. On the other hand, the “behavioral flexibility hypothesis” argues that resident species are selected to have higher cognitive capacities, and therefore larger brains, to enable survival in harsh winters, or to deal with environmental seasonality. Here, I test the validity and setting of these two hypotheses using 1466 globally distributed bird species. First, I show that the negative association between migration distance and relative brain size is very robust across species and phylogeny. Second, I provide strong support for the energetic trade‐off hypothesis, by showing the validity of the trade‐off among long‐distance migratory species alone. Third, using resident and short‐distance migratory species, I demonstrate that environmental harshness is associated with enlarged relative brain size, therefore arguably better cognition. My study provides the strongest comparative support to date for both the energetic trade‐off and the behavioral flexibility hypotheses, and highlights that both mechanisms contribute to brain size evolution, but on different ends of the migratory spectrum.     

Strong between‐site variation in New Caledonian crows’ use of hook‐tool‐making materials

Functional tool use requires the selection of appropriate raw materials. New Caledonian crows Corvus moneduloides are known for their extraordinary tool‐making behaviour, including the crafting of hooked stick tools from branched vegetation. We describe a surprisingly strong between‐site difference in the plant materials used by wild crows to manufacture these tools: crows at one study site use branches of the non‐native shrub Desmanthus virgatus, whereas only approximately 7 km away, birds apparently ignore this material in favour of the terminal twigs of an as‐yet‐unidentified tree species. Although it is likely that differences in local plant communities drive this striking pattern, it remains to be determined how and why crows develop such strong site‐specific preferences for certain raw materials.     

DO IMAGE-FORMING EYES PROMOTE EVOLUTIONARY DIVERSIFICATION?

It has been suggested that image-forming eyes promote the evolutionary diversification (measured by species richness) of the groups that possess them. Several different processes could give rise to this effect, including diversifying selection in a new adaptive zone (or zones) and a reduced rate of extinction due to enhanced competitive abilities. I tested the generality of the hypothesis that imaging eyes increase net speciation by comparing extant species numbers of 12 groups that have such eyes (as categorized by Land and Fernald 1992) with those of their cladistic sister groups that lack such organs. Even assuming the published hypotheses of phylogenetic relationships that most favor increased net speciation of visual groups, these comparisons show no significant association between imaging eyes and species richness. Increased activity, as indicated by published accounts of locomotory speed, is significantly associated with the evolution of image-forming eyes. This suggests that a large “visual adaptive zone” might be characterized by relatively high activity. However, when diversity comparisons are limited to eight cases in which the evolution of imaging eyes is associated with increased activity, there is still no significant association between such eyes and species richness. The fossil record indicates that the only visual groups that have undergone major evolutionary radiations evolved imaging eyes early in the history of metazoans (before the Silurian). The radiations of these early groups may have largely filled up niches for visual animals and thus prevented the subsequent proliferation of other groups with image-forming eyes. Alternatively, it may be that image-forming eyes have no exceptional effect on diversification or that their effects are obscured by other factors in the long run.     

Evolutionary innovations in Antarctic brittle stars linked to glacial refugia

The drivers behind evolutionary innovations such as contrasting life histories and morphological change are central questions of evolutionary biology. However, the environmental and ecological contexts linked to evolutionary innovations are generally unclear. During the Pleistocene glacial cycles, grounded ice sheets expanded across the Southern Ocean continental shelf. Limited ice‐free areas remained, and fauna were isolated from other refugial populations. Survival in Southern Ocean refugia could present opportunities for ecological adaptation and evolutionary innovation. Here, we reconstructed the phylogeographic patterns of circum‐Antarctic brittle stars Ophionotus victoriae and O. hexactis with contrasting life histories (broadcasting vs brooding) and morphology (5 vs 6 arms). We examined the evolutionary relationship between the two species using cytochrome c oxidase subunit I (COI) data. COI data suggested that O. victoriae is a single species (rather than a species complex) and is closely related to O. hexactis (a separate species). Since their recent divergence in the mid‐Pleistocene, O. victoriae and O. hexactis likely persisted differently throughout glacial maxima, in deep‐sea and Antarctic island refugia, respectively. Genetic connectivity, within and between the Antarctic continental shelf and islands, was also observed and could be linked to the Antarctic Circumpolar Current and local oceanographic regimes. Signatures of a probable seascape corridor linking connectivity between the Scotia Sea and Prydz Bay are also highlighted. We suggest that survival in Antarctic island refugia was associated with increase in arm number and a switch from broadcast spawning to brooding in O. hexactis, and propose that it could be linked to environmental changes (such as salinity) associated with intensified interglacial‐glacial cycles.     

Visual perception skills: a comparison between patients with Noonan syndrome and 22q11.2 deletion syndrome

Ventral and dorsal streams are visual pathways deputed to transmit information from the photoreceptors of the retina to the lateral geniculate nucleus and then to the primary visual cortex (V1). Several studies investigated whether one pathway is more vulnerable than the other during development, and whether these streams develop at different rates. The results are still discordant. The aim of the present study was to understand the functionality of the dorsal and the ventral streams in two populations affected by different genetic disorders, Noonan syndrome (NS) and 22q11.2 deletion syndrome (22q11.2DS), and explore the possible genotype–phenotype relationships. ‘Form coherence’ abilities for the ventral stream and ‘motion coherence’ abilities for the dorsal stream were evaluated in 19 participants with NS and 20 participants with 22q11.2DS. Collected data were compared with 55 age‐matched controls. Participants with NS and 22q11.2DS did not differ in the form coherence task, and their performance was significantly lower than that of controls. However, in the motion coherence task, the group with NS and controls did not differ, and both obtained significantly higher scores than the group with 22q11.2DS. Our findings indicate that deficits in the dorsal stream are related to the specific genotype, and that in our syndromic groups the ventral stream is more vulnerable than the dorsal stream.