Leghemoglobin-like sequences in the DNA of four actinorhizal plants

Summary A cloned cDNA partial copy of a soybean leghemoglobin mRNA was used to probe genomic DNA of four species of actinorhizal plants. Southern blot hybridization revealed the presence of sequences with homology to the leghemoglobin probe in DNA from Alnus glutinosa, Casuarina glauca, Ceanothus americanus and Elaeagnus pungens. The hybridization patterns of the restriction fragments revealed some fragment size conservation between the DNA of soybean and the DNA of four actinorhizal plants which are taxonomically unrelated to soybean or to each other. The results presented here indicate that globin gene sequences are much more widely distributed in the plant kingdom than has previously been thought. Furthermore, if sequence conservation is actually as high as the restriction fragment patterns suggest, the evolution of the DNA surrounding the globin sequences has been highly constrained.     

Alterations in the number of rRNA operons within the Bacillus subtilis genome

Deletions and additions of rRNA gene sets in Bacillus subtilis were observed by Southern hybridizations using cloned radiolabeled rDNA sequences. Of the ten rRNA gene sets found in B. subtilis 168M or NCTC3610, one was deleted in strains possessing the leuB1, ilvC1, argA2 and pheA1 mutations. Among EcoRI restriction fragments of genomic DNA products, a 2.9-kb 23S rRNA homolog was missing. In HindIII digest, both 5.5- and 5.1-kb hybrid bands were lost with 16S and 23S probes, respectively. Similarly, genomic DNAs digested with SmaI showed the absence of both 2.1- and 2.0-kb fragments that hybridized to 16S and 5S sequences, respectively, in wild-type genomes. In contrast, B. subtilis strain 166 and its derivatives displayed a gain of a 3.3-kb HindIII fragment homologous to 16S rRNA. Transforming the ilvC1 and leuB1 mutations into new genetic backgrounds revealed in some clones the concomitant introduction of the ribosomal defect. Transformations with the slightly heterologous donor DNA from strain W23 yielded some Leu+ and Arg+ transformants with altered hybridization patterns when probed with cloned sequences. We propose that the deletion of the rRNA operon occurred in the ilv-leu gene cluster of the B. subtilis genome as a result of unequal recombination between redundant sequences.     

Construction of a cosmid library of Spirulina platensis as an approach to DNA physical mapping

Abstract A Spirulina platensis gene library has been constructed using cosmid vector pMMB34. The cosmid bank was controlled for its random gene distribution by colony hybridization. Genes were identified using either homologous or heterologous probes of genes involved in photosynthesis (large and small subunit of d -ribulose 1,5-bisphosphate carboxylase, 32 kDa thylakoid protein, α, β subunits of C-phycocyanin) and protein synthesis (elongation factors EF-Tu, EF-G).     

南方菜豆花叶病毒外壳蛋白基因序列的分析

用重组DNA技术及序列分析法测定了南方菜豆花叶病毒RNA基因组3′端1,000个碱基的序列,以及由此序列推导出的整个外壳蛋白的氨基酸顺序,它与巳报导的基本上一致。介绍了用DNA的寡核苷酸水解混合物作为起始引物,以3′端不含PolyA尾巴且不能加上PolyA的病毒RNA作为模板合成互补DNA,及进一步无性繁殖此cDNA的方法。     

Pattern of conodont reworking in the Upper Devonian of the Alps: palaeoenvironmental and palaeotectonic implications

Transfer of sediments from shallow shelf to basin usually implies vertical (stratigraphic) reworking of fossils, but in a few instances produces only lateral reworking (actually within the time span of a subzone). An Upper Devonian (Frasnian) pelagic carbonate sequence with allodapic intercalations and thick intraclast parabreccias triggered by seismic shocks and related tsunami and turbidity currents has been studied. Here, the standard biozone sequence is undisturbed at the zonal as well as the subzonal level. However, distribution of conodonts is discontinuous, and ranges of some important species are altered; mature specimens are commonly broken, whereas complete specimens are mostly juvenile forms. Maxima and minima of element frequency and anomalous thickening or thinning of subzones are recognized. Such distribution patterns of conodonts are compared with the four main facies distinguished and related to the environmental interpretation (a platform-basin system, the original gentle slope of which was fragmenting in fault-controlled blocks). The mean frequency of shallow-water, proximal conodonts is 10% whereas transitional to distal deeper-water genera dominate throughout the entire section. In the dominant biofacies, conodonts settled vertically, in the subordinate one they were transported laterally. The 'intraclast parabreccia' is interpreted as a peculiar type of seismitc. The anomalous thickness variation of biozones is related to the step topography of the slope in a fault-controlled carbonate basin.     

Feeding habits of Japanese butterfyfishes (Chaetodontidae)

Synopsis Stomach content data from 32 species of Japanese butterflyfishes of the family Chaetodontidae were used to classify them into feeding groups and to determine their important food resources. Four major feeding groups were distinguished: (1) obligative coral feeders which prey exclusively or mostly on Scleractinian corals, (2) facultative coral feeders that take both corals and other benthic organisms, (3) noncoralline invertebrate feeders which consume benthic invertebrates other than corals, and (4) zooplankton feeders. Ten species representing 31% of the butterflyfishes belong to the first category. The second and third categories include 13 (41%) and 8 (25%) species, respectively. The fourth category is represented by only one species which picks individual zooplankters, especially calanoid copepods, in midwater above the reefs. Facultative coral feeders consumed varying quantities of scleractinians (from 2 to 74% of food volume), along with a variety of benthic organisms including algae, alcyonarians, sea anemones, sedentary polychaetes, sponges, hydroids, etc. Noncoralline invertebrate feeders, on the other hand, tend to have low diversified diets, predominated by one prey item such as sea anemones, zoanthideans, polychaetes, or colonial ascidians. These dietary data suggest that scleractinian corals are the most important food resource for the Japanese butterflyfishes, and next important are sea anemones, sedentary polychaetes, alcyonarians, and algae.     

Restriction fragment analysis of the secalin loci of rye

Analyses of wheat/rye addition lines by Southern blotting confirmed the presence of sequences related to theSec 1, Sec 2, andSec 3 loci on chromosomes 1R and 2R. Comparison of the 1R and 2R addition lines allowed the identification of -secalin genes atSec 1 andSec 2, respectively, while -secalin and -secalin genes atSec 1 were discriminated by comparative hybridization with three probes: -secalin, total -secalin, and 3 -secalin. The high molecular weight (HMW) secalin genes atSec 3 were identified using a homologous HMW subunit probe from wheat. Gene copy numbers were estimated as about 40–60 for -secalins, 5–10 for -secalins, and 2 for HMW secalins. Comparison of individual plants of cv. Gazelle showed a high degree of polymorphism, particularly for sequences related to -secalins and HMW secalins.     

Stratigraphy,facies and synsedimentary tectonics in the Jurassic Rosso Ammonitico Veronese (Altopiano di Asiago,NE Italy)

Summary The red, pelagic limestones of the Rosso Ammonitico Veronese (Upper Bajocian-Tithonian) of the Altopiano di Asiago area can be subdivided into eight facies. They differ from each other in structure (bedding style, presence and type of nodularity) and texture (nature of components, grain-vs mud-support, compactional features). Several discontinuities could be recognized, based on sedimentological or biostratigraphic evidence. In the context of a drowned platform, where sediments essentially consist of skeletal remains of both planktonic and benthic organism, the different facies are interpreted as reflecting a varying influence of currents on the winnowing of micrite and on triggering early cementation. Early cementation in turn, controlled the patterns of bioturbation and the response of sediments to later compaction and pressure-dissolution. At times, microbial mats, of unidentified nature, were important in trapping and binding sediment, giving rise to early lithified nodules and layers of stromatolitic aspect. The Rosso Ammonitico Veronese can be subdivided into three units: lower Rosso Ammonitico (RAI: Upper Bajocian-Lower Callovian), middle Rosso Ammonitico (RAM: Upper Callovian-Middle Oxfordian), and upper Rosso Ammonitico (RAS: Lower Kimmeridgian-Tithonian). Frequent ammonite moulds allow the precise dating of the base and top of each unit, and the documentation of facies heteropies and hiatusses in the more fossiliferous RAS. The lower unit (RAM) is massive and essentially nodular; the middle unit (RAM) is well bedded, non-nodular, and cherty; the upper unit (RAS) is richer in clay and typically nodular. The RAI and the RAS are present everywhere, though significant facies and thickness changes affect particularly the RAS; the RAM is much more variable, ranging from 0 to 10 metres. These variations, that may be gradual or abrupt, are inter-preted as the result of Middle-Late Callovian block-faulting which generated an irregular sea floor topography where the swells were more exposed to currents that continuously removed sediments, inducing long-lasting periods of nondeposition. Sediments preferentially accumulated in the adjacent lows. A confirmation of this hypothesis is provided by evidence of synsedimentary tectonics, described for the first time in the Rosso Ammonitico Veronese. Neptunian dykes, both vertical and horizontal, are developed at the top of the RAI and are filled with laminated sediments or collapse breccias. Glides of metre-size blocks and slumps are present at the top of the RAI and at the base of the RAM, respectively. Cm-thick layers of mud supported breccias are intercalated in the upper part of the RAI and within the RAM: they are interpreted as seismites. All these features document a tensional regime that generated fractures in more or less lithified sediments and failure along steep fault scarps or gently dipping slopes of tilted fault blocks. Recognition of this Callovian-Oxfordian tectonic activity shows that, after the Bajocian drowning, the Trento Plateau did not simply experience a uniform and general foundering: a small-scale block-faulting was still active and affected the pattern of facies distribution.     

滇南及滇东南胶孔菌复合群的分类地理研究

报道了我国滇南及滇东南热带、亚热带胶孔菌复合群众路线属６种,其中瘤丝牛肝菌Ｆｉｌｏｂｏｌｅｔｕｓ ｖｅｒｒｕｃｕｌｏｓｕｓ Ｐ．Ｇ．Ｌｉｕ和滇丝牛肝菌Ｆ．ｙｕｎｎａｎｅｎｓｉｓ Ｐ．Ｇ．Ｌｉｕ是新种,紫兰小菇Ｍｙｃｅｎａ ｖｉｏｌａｃｅｌｌａ（Ｓｐｅｑ．）Ｓｉｎｇ。是我国新纪录种;新种附有拉丁文描术和插图,新纪录和附有形态解剖图。本文所引证标本均存放于中国科学院昆明植物研究所隐花植物标本馆（ＨＫＡ     

皖南汉族的趾纹研究

本文对皖南地区520例汉族大学生的趾纹进行了调查分析,计算出了各型趾纹频率、趾纹组合、趾嵴纹计数等项参数。比较了不同性别、不同侧别和不同人种间的差异,分析了趾纹类型和趾嵴纹计数在各趾的分布特点,并对差异的原因进行了讨论。Abstract: The authors inverstigated and analysed the toe prints of 520 cases of good healthy students in Wannan area of Aahui, and calculated the frequency of various toe patterns, combinations of toe patterns, toe ridge counts (TRC) and so on. The differences between sexes, sides and reces were compared. The distributive character of toe patterns and toe ridge count on every toe were analysed. The different cause were discussed.