我国内蒙古褐斑鼠兔一新亚种

在我国,褐斑鼠兔(帕氏鼠兔或蒙古鼠兔)Ochotona pallasi的记录,过去只有Thoma(1912)根据新疆哈密县天山的6标本所发表的哈密亚种O.p.hamica。我们于1972—1973及1975—1976年间在内蒙古和新疆采到一些褐斑鼠兔标本。经研究,采自新疆北塔山的13个标本属蒙古亚种O.p.pricei,为我国亚种的新纪录;采自内蒙古的11个标本则为新亚种,描记于下。     

北塔山地区褐斑鼠兔的生活习性

褐斑鼠兔(Ochotona pallasi)又称帕氏鼠兔,在我国分布于内蒙古和新疆。其有关生物学资料,国内尚无专门的报道。我们于1975年6月、1976年7—8月,在新疆北部北塔山地区,对褐斑鼠兔的生活习性进行了观察和了解,现整理如下。     

中华鼠兔一新种(兔形目,鼠兔科)

本文记录了中华鼠兔一新种——乌伦古中华鼠兔(Sinolagomys ulungurensis sp.nov.)。标本采自新疆北部乌伦古河北岸的晚渐新世索索泉组。材料表明:中华鼠兔,特別是乌伦古种,与中新世亚洲跑兔(Bellatona)和非洲的肯尼亚鼠兔(Kenyalagomys)有较接近的牙齿形态。     

木垒草原兔尾鼠数量下降期种群结构变化

2000年9月至2001年9月在新疆木垒县分4个时段采用样方法对草原兔尾鼠(Lagurus lagurus)进行野外调查,实验室采用数学生态学方法研究草原兔尾鼠的种群年龄结构和繁殖结构变化。结果表明,随着草原兔尾鼠数量的下降,种群的年龄结构和繁殖结构都发生了明显的变化。     

新疆黄兔尾鼠的分布及其生态习性的初步观察

黄兔尾鼠(Lagurus luteus)为我国新疆北部地区的特有种。据等(1977),青海和蒙古高原地区的黄兔尾鼠应属另一种(L.Przewalskii)。以往仅有少量蒙古黄兔尾鼠的生态资料(Allen 1940,1954,1968)。一直到1968年,黄兔尾鼠数量骤然升高,一部分黄兔尾鼠移入苏联斋桑盆地的东部,等(1969)才做了一些观察和报道。由于该种的数量波动极大,在低数量年份连其踪迹也不易寻觅,故我国也无人对其分布和生态专门进行研究。1974—1976年作者于新疆北部地区进行了鼠类区系调查,并于木垒县大石头公社连续做了4个月(1976年6—9月)的野外观察,现简报如下。     

褐斑鼠兔对草场的危害及防治后的效益

啮齿动物对草原的危害,已引起人们的普遍重视。本文就新疆北塔山奇台县地区,褐斑鼠兔(帕氏鼠兔)Ochotona pallasi对草场的破坏作用及防冶后牧草生长状况、植被组成的演     

伊犁鼠兔分布区与栖息地的初步研究

据目前调查所知,伊犁鼠兔的分布区仅限于新疆北天山的婆罗科努山和伊连哈比尔尕山。该鼠兔为裸岩栖息型动物,栖息地为海拔2800—4100米的亚高山草甸、高山草甸及垫状植被带的裸岩区。     

黄兔尾鼠防治中经济阈值的探讨

本文以新疆荒漠草原的主要害鼠——黄兔尾鼠Lagurus luteus为例,应用经济阈值,对该鼠的防治指标作了探讨。为确定草场鼠害的防治指标提供一种可行的测算方法。     

鼠兔属一新种

1983和1985年作者在新疆尼勒克县境内的天山山区采到3只体型较大的鼠兔,其额部和顶部及颈侧有锈棕色斑;其耳长和后足长均为鼠兔属(Ochotona)已知各种中最大者;额骨较平坦,眶间宽达5.3毫米,大于颅基长的11％。经鉴定为一新种,订名为伊犁鼠兔Ochotona iliensis Li et Ma sp.     

两种兔尾鼠的化学信息及其在群体中的作用

黄兔尾鼠(Lagurus lutens)及草原兔尾鼠(Lagurus lagurus)是新疆某些地区主要害鼠之一,它们的繁殖能力很强,数量高峰时,对草场危害极大。此外,它们还能传染某些地方性流行病,所以对这两种害鼠的防治是十分必要的。 近年来,我们在研究动物化学通讯的过程中,了解到外激素(信息素)在动物间传递信     

PRODUCTION OF AXENIC CULTURES OF MICROMONAS PUSILLA (PRASINOPHYCEAE) USING ANTIBIOTIC 1

Bacteria-free cultures of the prasinophyte Micromonas pusilla (Butcher) Monton and Parke, UTEX LB 991, were produced by intially determining the effects of several antibiotics on the growth of this alga and then using a combination of these antibiotics to eliminate associated bacteria, Micrononas pusilla was resistant ot penicillin G, neomycin, gentamicin and streptomycin at bactericidal concentrations but sensitive to chloramphenicol and polymixin B. Passage of M. pusilla through the sequence of antibioties penicillin G → neomycin → gentamician → kanamycin resulted in an axenic culture of M, pusilla this method should be suitable for producing axenic culture of other strains of M. pusilla.     

The molecular heterogeneity of hemocyanin: Structural and functional properties of the 4x6-meric protein of Upogebia pusilla (Crustacea)

The structural properties of the hemocyanin isolated from the Mediterranean mud shrimp, Upogebia pusilla (Decapoda: Thalassinidea), were investigated. Our intent was to make use of the U. pusilla case to perform a structural comparison between crustacean and chelicerate 4x6-meric hemocyanins. The thalassinidean hemocyanin appears similar in size but different in structural organization compared to the chelicerate 4x6-mer. Ultracentrifuge analyses on the purified protein revealed a sedimentation coefficient of 39S, typical of 4x6 hemocyanins. Electron micrographs are in agreement with a model in which four 2x6-meric building blocks are arranged in a tetrahedron-like quaternary structure and not in the quasi-square-planar orientation characteristic of the chelicerate protein. Size-exclusion chromatography-fast protein chromatography analysis showed elevated instability of the protein in absence of divalent ions or at pH values higher than 8.0. This analysis also shows that the dissociation of the U. pusilla 4x6-meric hemocyanin into hexamers occurs without any intermediate 2x6-meric state, in contrast with the dissociation profile of the chelicerate protein exhibiting several dissociation intermediates. The oxygen-binding properties of U. pusilla hemocyanin were studied to disclose possible effects by the typical allosteric effectors that modulate the functional properties of crustacean hemocyanin. A marked Bohr and lactate effect, but no significant influence of urate, on the oxygen affinity of U. pusilla hemocyanin were found.     

Complete chloroplast genome sequence of an orchid model plant candidate: Erycina pusilla apply in tropical Oncidium breeding

Oncidium is an important ornamental plant but the study of its functional genomics is difficult. Erycina pusilla is a fast-growing Oncidiinae species. Several characteristics including low chromosome number, small genome size, short growth period, and its ability to complete its life cycle in vitro make E. pusilla a good model candidate and parent for hybridization for orchids. Although genetic information remains limited, systematic molecular analysis of its chloroplast genome might provide useful genetic information. By combining bacterial artificial chromosome (BAC) clones and next-generation sequencing (NGS), the chloroplast (cp) genome of E. pusilla was sequenced accurately, efficiently and economically. The cp genome of E. pusilla shares 89 and 84% similarity with Oncidium Gower Ramsey and Phalanopsis aphrodite, respectively. Comparing these 3 cp genomes, 5 regions have been identified as showing diversity. Using PCR analysis of 19 species belonging to the Epidendroideae subfamily, a conserved deletion was found in the rps15-trnN region of the Cymbidieae tribe. Because commercial Oncidium varieties in Taiwan are limited, identification of potential parents using molecular breeding method has become very important. To demonstrate the relationship between taxonomic position and hybrid compatibility of E. pusilla, 4 DNA regions of 36 tropically adapted Oncidiinae varieties have been analyzed. The results indicated that trnF-ndhJ and trnH-psbA were suitable for phylogenetic analysis. E. pusilla proved to be phylogenetically closer to Rodriguezia and Tolumnia than Oncidium, despite its similar floral appearance to Oncidium. These results indicate the hybrid compatibility of E. pusilla, its cp genome providing important information for Oncidium breeding.     

Genetic relationships and population structure within taxa of the endemic Sideritis pusilla (Lamiaceae) assessed using RAPDs

RAPD analysis has been performed for 15 plant populations, covering eight different infraspecific taxa of Sideritis pusilla (Lange) Pau, member of the Lamiaceae endemic to southeastern Spain, and their putative parental species Sideritis hirsuta L. and Sideritis Uucantha Cav. Genetic distances, together with the presence of numerous fixed molecular markers differentiating S. pusilla from its putative ancestors, indicate that it should be considered as a true species. Cladistic and populational analysis led to the allocation of S. pusilla populations into three major groups– osteoxylla, jlavovirens and pusilla/almeriensis –which include taxa previously described as ranging from the varietal to the specific level. Low genetic differentiation among groups revealed by a reduced number of specific molecular markers justify their assignment under the infraspecific range. Moreover, the existence of both morphological and biogeographical differences, supports a status for these groups as subspecies of S. pusilla. Highly significant ( P <0.002) variance partitioning data (AMOVA) extracted from the analysis of individuals within S. pusilla populations show that, of the total genetic diversity, 68.8% was attributable to individual differences within populations, 19.9% to populational differences within groups, and only 11.3% to divergence between groups. This distribution is in agreement with the outcrossing nature of these plants. Comparative analysis of variance within populations reveals a reduced genetic variation for the osteoxylla group, thus supporting its previous consideration as an endangered taxon.     

Ecological niche partitioning in the picoplanktonic green alga Micromonas pusilla: evidence from environmental surveys using phylogenetic probes

Very few studies have analysed the niches of pelagic protist in details. This is because for most protists, both an accurate species definition and methods for routine detection and quantification of cells are lacking. The morphospecies Micromonas pusilla , a marine unicellular green alga, is the most ubiquitous and cosmopolitan picoeukaryote described to date. This species comprises several independent genetic lineages or clades, which are not currently distinguishable based on comparison of their morphology or biogeographical distribution. Molecular probes were used to detect and quantify the genetic clades of M. pusilla in samples from temperate, polar and tropical environments in order to assess potential ecological niche partitioning. The three clades were detected in all biogeographical regions studied and were commonly found in sympatry. Cell abundances recorded for clades A and B were high, especially at coastal stations. Clade C, when detected, was always at low abundances and is suggested to be a low-light clade. Shifts in the contribution of clades to total M. pusilla abundance were observed along environmental gradients, both at local and basin-wide scales. This suggests that the phylogenetic clades occupy specific niches and confirms the existence of cryptic species within the morphospecies M. pusilla . Parameters which can precisely explain the distribution of these cryptic species remain to be elucidated.     

Heritable variation in quinone-induced haustorium development in the parasitic plant Triphysaria

We are using the facultative hemiparasite, Triphysaria, as a model for studying host-parasite signaling in the Scrophulariaceae. Parasitic members of this family form subterranean connections, or haustoria, on neighboring host roots to access host water and nutrients. These parasitic organs develop in response to haustorial-inducing factors contained in host root exudates. A well-characterized inducing factor, 2, 6-dimethoxy-p-benzoquinone (DMBQ), can be used to trigger in vitro haustorium formation in the roots of Triphysaria. We have assayed three species, Triphysaria eriantha (Benth.) Chuang and Heckard, Triphysaria pusilla (Benth.) Chuang and Heckard, and Triphysaria versicolor Fischer and C. Meyer, for haustorium development in response to DMBQ. There were significant differences between the species in their ability to recognize and respond to this quinone. Ninety percent of T. versicolor individuals responded, whereas only 40% of T. pusilla and less than 10% of T. eriantha formed haustoria. Within field collections of self-pollinating T. pusilla, differential responsiveness to DMBQ was seen in distinct maternal families. Assaying haustorium development in subsequent generations of self-pollinated T. pusilla showed that DMBQ responsiveness was heritable. Reciprocal crosses between T. eriantha and T. versicolor demonstrated that DMBQ responsiveness was influenced by maternal factors. These results demonstrate heritable, natural variation in the recognition of a haustorial-inducing factor by a parasitic member of the Scrophulariaceae.     

Phylogenetic diversity of bacterial symbionts of Solemya hosts based on comparative sequence analysis of 16S rRNA genes.

The bacterial endosymbionts of two species of the bivalve genus Solemya from the Pacific Ocean, Solemya terraeregina and Solemya pusilla, were characterized. Prokaryotic cells resembling gram-negative bacteria were observed in the gills of both host species by transmission electron microscopy. The ultrastructure of the symbiosis in both host species is remarkably similar to that of all previously described Solemya spp. By using sequence data from 16S rRNA, the identity and evolutionary origins of the S. terraeregina and S. pusilla symbionts were also determined. Direct sequencing of PCR-amplified products from host gill DNA with primers specific for Bacteria 16S rRNA genes gave a single, unambiguous sequence for each of the two symbiont species. In situ hybridization with symbiont-specific oligonucleotide probes confirmed that these gene sequences belong to the bacteria residing in the hosts gills. Phylogenetic analyses of the 16S rRNA gene sequences by both distance and parsimony methods identify the S. terraeregina and S. pusilla symbionts as members of the gamma subdivision of the Proteobacteria. In contrast to symbionts of other bivalve families, which appear to be monophyletic, the S. terraeregina and S. pusilla symbionts share a more recent common ancestry with bacteria associating endosymbiotically with bivalves of the superfamily Lucinacea than with other Solemya symbionts (host species S. velum, S. occidentalis, and S. reidi). Overall, the 16S rRNA gene sequence data suggest that the symbionts of Solemya hosts represent at least two distinct bacterial lineages within the gamma-Proteobacteria. While it is increasingly clear that all extant species of Solemya live in symbiosis with specific bacteria, the associations appear to have multiple evolutionary origins.     

Water conservation in the South American desert mouse opossum, Thylamys pusilla (Didelphimorphia, Didelphidae).

The aim of this paper was to analyze the renal performance of the insectivorous desert mouse opossum, Thylamys pusilla, a marsupial that inhabits temperate drylands of the Neotropics. We measured the urine concentrating ability of this marsupial in the field and under three different experimental conditions in the laboratory. (1) Ad libitum treatment: animals were fed ad lib. on apples, sausages and cat food; (2) restriction treatment: foods high in nitrogen were supplied ad lib., while only apple, a food with high water to nitrogen load, was restricted, and (3) fasting: 2 days of food deprivation. Osmolarity values recorded in the field were similar to those obtained under the restriction treatment. The maximum urinary concentration found (9015 mOsm/l) is the highest reported for a marsupial and more in keeping with similarly sized desert rodents. Similar urine concentrations in T. pusilla and desert rodents suggest that xeric environments, rather than phylogeny, play a major role in water conservation. The kidney of T. pusilla possesses a long papilla and shows high renal indices (M/C: 9.37; RMT: 11.76). Our results question the idea that urine concentration is not high in desert-dwelling insectivores. Although their dietary water intake is potentially high, this may not always be sufficient to eliminate the nitrogenous waste resulting from insectivory. Thus, T. pusilla uses its ability to conserve water to overcome periods of food shortage and high nitrogen load.     

Pollination ecology of Arum italicum (Araceae)

The pollination ecology of Arum italicum was studied in south-western France. This plant attracts olfactory dung-breeding flies through deceit. These insects are principally represented by Diptera, all belonging to saprophyte families. The volatilization of the odouriferous compounds, responsible for their attraction, is achieved through the production of heat by the appendix. The insects are trapped for 24 h in order to participate in both sexual phases of the protogynous inflorescence. The male flowers produce three heat events during flowering. These peaks of heat seem to be involved in the spathe movements, since they occur during the opening of the inflorescence and the liberation of the insects. The last male heat event may be linked with the liberation of pollen and its dispersion by stimulating trapped flies. According to their frequency and pollen-load, two Psychoda species appear to be the most efficient pollinators ( P. crassipenis and P. pusilla ). Nevertheless, each of the other attracted species could play a significant role under different spatio-temporal conditions. Experiments on self-pollination have shown that obligate cross-pollination is necessary for A. italicum to set seeds. Moreover, hand- and natural-pollinated plants showed similarly high abortion frequencies suggesting that seed set may be more constrained by resources rather than by pollination limitation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 205–214.     

Redescription of Rhodopsis pusih Bush, a little known but widely distributed species of Serpullidae (Polychaeta)

Rhodopsis pusilla Bush 1905. a minute species characterized by a chitinous opereular plate bearing numerous spines is redescribed and a neotype is designated. Apomatolos Uchida. 1978 is synonymized with Rhodopsis . Ventral fillform mouth-palps are present a rarely observed character in common with Pseudovermilia Bush. Variability between and within populations from different seas is discussed. Rhodopsis pusilla from Heron Island shows opercular dimorphism. Pouch-like brood chambers similar in texture (SEM) to the Rhodopsis tubes and integrally associated with rings marking successive position of the peristome were found on some tubes. These brood chambers. presumed to belong to Rhodopsis are described with conjectures as to their mode of formation. Some aspects of opercular polymorphism in serpulids are discussed.