Classification of types of ontogenetic reproduction

The object of this paper is to present an original classification of ontogenetic reproduction. The main general criterion used is the degree and type of phylogenetic differentiation. In relation to this criterion, criteria are given for the classification of the fundamental types of ontogenetic reproduction and for the classification of the types of ontogenetic generation cycles. Between the fundamental types of ontogenetic reproduction and the types of ontogenetic generation cycles there is a hierarchical relationship which shows that the former are components of the latter. Between the well-defined types of ontogenetic reproduction there exist many intermediate types.     

The distribution of hair of the lower limb in white and Negro males

Four types of distribution of terminal hair of the lower limb are recognized. These types are pedo-cruro-femoral, cruro-femoral, pedo-femoral and femoral. These are correlated with the types of distribution of terminal hair of the upper limb, and their incidence is reported. In addition, three hair patterns of the leg are named and described.     

灯台树(Cornus controversa)导管分子穿孔板的类型

对灯台树茎次生木质部离折材料进行观察研究,发现其导管分子穿孔板有梯状穿孔和单穿孔板2种类型,并且其单穿孔板的穿孔外展。具不同类型穿孔板的导管分子有4种类型,即两端均为梯状穿孔板的导管; 端是梯关穿孔板,另一端是单穿孔板的导管分子;一端有2个单穿孔板,另一端是梯状穿孔板的导管分子;两端均为单穿孔板的导管分子。     

Theoretical Study of DNA unwinding under the action of formaldehyde.

A simple model is used to investigate the relationship between clone number and patch number for each of two cell types in one and two-dimensional arrays. Considering the two cell types separately, this relationship is shown to vary with the relative proportions of the two cell types. If both cell types are considered, the total number of patches in a one-dimensional array reaches a maximum when the two cell types are present in equal proportions. Over the range considered for a two-dimensional array, the total number of patches is at a minimum when the two cell types are present in equal proportions because aggregation of patches is then maximal. The significance of these results is discussed in the light of previous interpretations of work with mouse aggregation chimaeras.     

根癌土壤杆菌C58 Cereon中分泌蛋白信号肽分析

利用SignalP3．0、LipoP1．0、TMHMM2．0和TargetP1．014种蛋白分析软件预测了Agrobacterium tumefaciens C58 Cereon菌株全部基因组的4554个ORF编码的蛋白信号肽,共发现203个信号肽,且它们的氨基酸残基相对保守。其中158条具分泌型信号肽,9条具RR-motif型信号肽,28条具信号肽酶Ⅱ型信号肽,8条具细菌素-信息素型信号肽,但只有分泌蛋白AGR-C-1878p和AGR-C-1880p的信号肽氨基酸残基完全相同,表明信号肽是高度变异的。     

灯台树(Cornus controversa)导管分子穿孔板的类型

对灯台树茎次生木质部离析材料进行观察研究,发现其导管分子穿孔板有梯状穿孔板和单穿孔板2种类型,并且其单穿孔板的穿孔外展.具不同类型穿孔板的导管分子有4种类型,即两端均为梯状穿孔板的导管分子;一端是梯状穿孔板,另一端是单穿孔板的导管分子;一端有2个单穿孔板,另一端是梯状穿孔板的导管分子;两端均为单穿孔板的导管分子.     

Structure of sensilla trichodea of female Aedes aegypti with comments on innervation of antennal sensilla

On each antenna of female Aedes aegypti four types of sensilla trichodea are distinguishable: long and short, pointed-tipped ones and blunt-tipped types I and II. All types are innervated by two neurones, except the short, pointed-tipped trichodea with which only one neurone is associated. Both pointed-tipped types have unbranched dendrites and relatively thicker hair walls perforated by fewer pores than the blunt-tipped types. The long, pointed-tipped trichodea are 50–60 μm in length and the short ones 20 μm. In both blunt-tipped types the dendrites divide and the hair walls are perforated by numerous pores. Blunt-tipped type I trichodea are 20–40 μm in length and taper somewhat whereas the type II hairs are 11–13 μm in length, do not taper appreciably, and have exceedingly thin walls. All types of sensilla trichodea are olfactory receptors and the blunt-tipped type I are known to respond to repellents.An investigation of the possibility of axon fusion in the flagellar nerve gave negative results.Each flagellar nerve is composed of an estimated 2058 neurones. A majority of these, namely 93%, are involved in the recognition and discrimination of olfactory cues. Approximately 65% of the neurones respond to repellents, 5% to mechanical stimuli, and 2% to heat transferred by convection.     

Factors determining distributions of tree species and plant functional types

Plant functional types have been identified by the International Geosphere Biosphere Program as functionally similar basic plant types, especially trees, as needed for global ecological modeling. Based to some extent on an earlier set of pheno-physiognomically defined plant types, a Global Biome Model was produced but has not satisfied all the desired functional criteria posed by IGBP physiologists and modelers. This paper asks two questions: what are the main environmental factors which limit terrestrial plant types, especially tree types; and how many types of potential vegetation are needed to cover the world's terrestrial vegetation patterns? Based on the main environmental factors recognized, a model of world potential dominant vegetation types was produced and used to estimate the minimal number of vegetation types needed. The resulting set of 40 potential dominant vegetation types may serve as an initial basis for a structural-functionally based set of world plant functional types.     

Habituation,Recovery and the Similarity of Song Types within Repertoires in Red-winged Blackbirds (Agelaius phoeniceus) (Aves,Emberizidae)

Male red-winged blackbirds (Agelaius phoeniceus) respond to playback of conspecific song on their territories with the song spread, a graded aggressive display in which males extend their wings to expose their red epaulets while singing. We show that the intensity of song spread display declines with repeated presentation of one song type, and recovers when song types are switched. Recovery is greater for switches between song types that are acoustically dissimilar than for switches between song types that are acoustically similar. Recovery is no different for switches between two song types taken from the repertoires of different males than for switches between song types recorded from the same male. Analysis of acoustic features also indicates that song types recorded from different males are not more dissimilar than are song types from the same male. Our results do not support the idea that repertoires of red-winged blackbirds are composed of similar song types in order to facilitate individual recognition. Rather, repertoires may be constructed of dissimilar song types, so as to help maintain the response of listeners despite habituation.     

Aggregation and Competitive Exclusion: Explaining the Coexistence of Human Papillomavirus Types and the Effectiveness of Limited Vaccine Conferred Cross-Immunity

Human Papillomavirus (HPV) types are sexually transmitted infections that cause a number of human cancers. According to the competitive exclusion principle in ecology, HPV types that have lower transmission probabilities and shorter durations of infection should be outcompeted by more virulent types. This, however, is not the case, as numerous HPV types co-exist, some which are less transmissible and more easily cleared than others. This paper examines whether this exception to the competitive exclusion principle can be explained by the aggregation of infection with HPV types, which results in patchy spatial distributions of infection, and what implications this has for the effect of vaccination on multiple HPV types. A deterministic transmission model is presented that models the patchy distribution of infected individuals using Lloyd??s mean crowding. It is first shown that higher aggregation can result in a reduced capacity for onward transmission and reduce the required efficacy of vaccination. It is shown that greater patchiness in the distribution of lower prevalence HPV types permits co-existence. This affirms the hypothesis that the aggregation of HPV types provides an explanation for the violation of the competitive exclusion principle. Greater aggregation of lower prevalence types has important implications where type-specific HPV vaccines also offer cross-protection against non-target types. It is demonstrated that the degree of cross-protection can be less than the degree of vaccine protection conferred against directly targeted types and still result in the elimination of non-target types when these non-target types are patchily distributed.     

The key role of atom types, reference states, and interaction cutoff radii in the knowledge-based method: new variational approach

We present a variational method to derive knowledge-based potentials. The method is based on an optimization procedure of objective variables: atom types, reference states, and interaction cutoff radii. We suggest and apply new unsymmetrical reference states. The cutoff radii and atom types are optimized to improve docking accuracy of the corresponding potentials. The atom types are varied along an atom type tree, with 6 root and 49 top atom types, and the set of 18 optimal atom types is obtained. We demonstrate strong dependence between the choice of atom types and the docking accuracy of the potentials derived with these atom types. The averaged root-mean square deviations (RMSDs) of the ligand docked positions relative to the experimentally determined positions decrease when the elements C, N, O are split into the optimal types.     

秦岭石瓮山地植被研究

石瓮山地共有野生种子植物113科,421属,813种。其植物区系具有地理成分复杂、分布类型多样、温带性质强烈、区系起源古老、特有现象明显的特点。植被类型多样,有3个植被型组、9个植被型、10个植被亚型、16个群系组和41个群系。     

The diversity of neurosecretory cell types in the cave tick Ornithodoros tholozani

Neurosecretory cells are arranged in 16 NSC centers in the different regions of the brain of O. tholozani. The component cells belong to 13 different types, of which five types are paraldehyde fuchsin positive and the remaining types are negative. Three of these cell types are here described for the first time. Some of these NSC show an affinity to certain localities inside the brain. Cells comprising a neurohaemal organ were found near the exit of the esophagus.     

Gamete signalling underlies the evolution of mating types and their number

The gametes of unicellular eukaryotes are morphologically identical, but are nonetheless divided into distinct mating types. The number of mating types varies enormously and can reach several thousand, yet most species have only two. Why do morphologically identical gametes need to be differentiated into self-incompatible mating types, and why is two the most common number of mating types? In this work, we explore a neglected hypothesis that there is a need for asymmetric signalling interactions between mating partners. Our review shows that isogamous gametes always interact asymmetrically throughout sex and argue that this asymmetry is favoured because it enhances the efficiency of the mating process. We further develop a simple mathematical model that allows us to study the evolution of the number of mating types based on the strength of signalling interactions between gametes. Novel mating types have an advantage as they are compatible with all others and rarely meet their own type. But if existing mating types coevolve to have strong mutual interactions, this restricts the spread of novel types. Similarly, coevolution is likely to drive out less attractive mating types. These countervailing forces specify the number of mating types that are evolutionarily stable.This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’.     

External morphology of antennal sensilla of trichogramma australicum girault (Hymenoptera : Trichogrammatidae)

External morphology of antennal sensilla on female and male Trichogramma australicum (Hymenoptera : Trichogrammatidae) was examined using scanning electron microscopy. Antennae show strong sexual dimorphism in structure and types of sensilla. The female antenna displays 14 types of sensilla: basiconic capitate peg sensilla (types 1 and 2), campaniform sensilla, chaetica sensilla (types 1–3), coeloconic sensilla, falcate sensilla, placoid sensilla (types 1 and 2), styloconic sensilla and trichoid sensilla (types 1–3). The male antenna displays 12 types of sensilla: basiconic capitate peg sensilla (type 2), campaniform sensilla, chaetica sensilla (types 1–5), coeloconic sensilla, placoid sensilla (type 1), and trichoid sensilla (types 3–5). Falcate and styloconic sensilla occur only on the female antenna. Both sensilla probably are associated with host examination, host discrimination and oviposition behaviour. Male antennal trichoid sensilla types 4 and 5 are probably associated with courtship behaviour, because these types occur only on the male. We propose the term “falcate sensilla” for a unique female antennal sensilla; the number of falcate sensilla may be used for identification of Trichogramma spp. In addition, we report the presence of placoid sensilla type 2 and difference in structure of coeloconic sensilla in T. australicum. Variation in structure and position of antennal sensilla are discussed.     

Morphology and histochemistry of the ambiens muscle of the red-eared turtle (Pseudemys scripta)

Six fiber types have been described in the ambiens muscle of red-eared turtles. These include one slow oxidative type, two fast oxidative types, two fast oxidative and glycolytic types, and one fast glycolytic type. Fiber types are non-randomly distributed throughout cross sections of the muscle. There is a decreasing gradient of oxidative staining and an increasing gradient of glycolytic staining along an axis from the superficial to deep regions of the muscle. The slow oxidative fibers are predominantly located within one or two fascicles of the superficial surface of the muscle. The fast glycolytic fibers are predominant in deep fascicles. In contrast to previous reports of histochemically monotypic intrafusal fibers in turtle muscle, ambiens muscle spindles have been observed containing one to eleven intrafusal fibers, including two fiber types. Fiber diameter and area are consistently smaller than observed in most extrafusal fibers. Spindles are predominantly located in superficial and cranial fascicles of the ambiens muscle and are located in regions characterized by extrafusal fibers with high oxidative activity.     

Morphofunctional analysis of Late Paleozoic conodont elements and apparatuses

Five functional types are recognized among Late Paleozoic conodont elements; they are distinguished by morphological and histological characteristics: grasping-holding, filtering, cutting, crushing, and grinding. Combinations of functional types of elements form functional types of conodont apparatuses, the main of which are filtering, grasping-cutting, grasping-pressing, grasping-cutting-grinding, and grasping-cutting-crushing apparatuses.     

A Hierarchical Classification of Benthic Biodiversity and Assessment of Protected Areas in the Southern Ocean

An international effort is underway to establish a representative system of marine protected areas (MPAs) in the Southern Ocean to help provide for the long-term conservation of marine biodiversity in the region. Important to this undertaking is knowledge of the distribution of benthic assemblages. Here, our aim is to identify the areas where benthic marine assemblages are likely to differ from each other in the Southern Ocean including near-shore Antarctica. We achieve this by using a hierarchical spatial classification of ecoregions, bathomes and environmental types. Ecoregions are defined according to available data on biogeographic patterns and environmental drivers on dispersal. Bathomes are identified according to depth strata defined by species distributions. Environmental types are uniquely classified according to the geomorphic features found within the bathomes in each ecoregion. We identified 23 ecoregions and nine bathomes. From a set of 28 types of geomorphic features of the seabed, 562 unique environmental types were classified for the Southern Ocean. We applied the environmental types as surrogates of different assemblages of biodiversity to assess the representativeness of existing MPAs. We found that 12 ecoregions are not represented in MPAs and that no ecoregion has their full range of environmental types represented in MPAs. Current MPA planning processes, if implemented, will substantially increase the representation of environmental types particularly within 8 ecoregions. To meet internationally agreed conservation goals, additional MPAs will be needed. To assist with this process, we identified 107 spatially restricted environmental types, which should be considered for inclusion in future MPAs. Detailed supplementary data including a spatial dataset are provided.     

Song structure,behaviour, and sequence of song types in a population of village indigobirds, Vidua chalybeata

Different song types are associated with certain behaviours including intrasexual aggression, mating, and initiation of song bouts. All song types are used in territorial advertisement. Songs associated with sexual and aggressive behaviours are similar in structure; female mate choice may have driven sexual selection in favour of the more aggressive males. Song sequence is non-random with repetition of all song types and alternation of some, and songs with similar messages are often associated in sequence. Predictions from alternative models were tested, but the significance of the large song repertoire in this species is largely explained by the message content of the different song types.