Two Mychonastes isolated from freshwater bodies are novel potential feedstocks for biodiesel production

Microalgae have been considered as ideal feedstocks for biodiesel production but the potential application is still under investigations. Here, eight kinds of microalgae were identified from water samples based on the morphologic and phylogenetic analyses. Among these eight microalgae, two Mychonastes S4 and S15 exhibited relative faster growth rate in the early culture stage and the highest contents of lipids. The two Mychonastes also showed higher C18:1 contents than the two Chlorella which were traditionally considered to be potential species for biodiesel production. As one kind of less researched microalgae, this study suggests Mychonastes should be a potential feedstock for biodiesel production. The application of the microalgal biodiesel still have some limiting factors, however, it is promising based on better lipid extraction technology and more relevant studies.     

Bioinformatic characterization of the extracellular lipases from Kluyveromyces marxianus

Lipases are hydrolytic enzymes that break the ester bonds of triglycerides, generating free fatty acids and glycerol. Extracellular lipase activity has been reported for the nonconventional yeast Kluyveromyces marxianus, grown in olive oil as a substrate, and the presence of at least eight putative lipases has been detected in its genome. However, to date, there is no experimental evidence on the physiological role of the putative lipases nor their structural and catalytic properties. In this study, a bioinformatic analysis of the genes of the putative lipases from K. marxianus L-2029 was performed, particularly identifying and characterizing the extracellular expected enzymes, due to their biotechnological relevance. The amino acid sequence of 10 putative lipases, obtained by in silico translation, ranged between 389 and 773 amino acids. Two of the analysed putative proteins showed a signal peptide, 25 and 33 amino acids long for KmYJR107Wp and KmLIP3p, and a molecular weight of 44.53 and 58.23 kDa, respectively. The amino acid alignment of KmLIP3p and KmYJR107Wp with the crystallized lipases from a patatin and the YlLip2 lipase from Yarrowia lipolytica, respectively, revealed the presence of the hydrolase characteristic motifs. From the 3D models of putative extracellular K. marxianus L-2029 lipases, the conserved pentapeptide of each was determined, being GTSMG for KmLIP3p and GHSLG for KmYJR107Wp; besides, the genes of these two enzymes (LIP3 and YJR107W) are apparently regulated by oleate response elements. The phylogenetic analysis of all K. marxianus lipases revealed evolutionary affinities with lipases from abH15.03, abH23.01, and abH23.02 families.     

Spores morphology of the family Pteridaceae from Shandong Province,China

In this article, we explored systematically the spore morphology of Pteridaceae by observation of the species distributed in Shandong Province using scanning electron microscopy (SEM). The results showed that the spore morphology of all the species in the family is tetrahedral and trilete. The characters of spore ornamentation are intraspecies stable, but significantly different among species and genera. Spore morphology is significant in exploring the phylogenetic relationships of Pteridaceae as well as in generic and specific delimitations.     

Morphological and Genetic Diversities of Habenaria radiata (Orchidaceae) in the Kinki Area,Japan

Floral organs have evolved from leaves for reproduction, and the morphological analyses help to understand the plant diversity and evolution. Habenaria radiata (syn. Pecteilis radiata) is a terrestrial orchid living in wetlands in Japan, Russia, South Korea, and China. The habitats of this plant in Japan have been reduced because of environmental destruction and overexploitation, and thus it is on the Red List of Japan as a Near Threatened species. One of the three petals of the H. radiata flower is called a lip or labellum, which resembles a flying white bird, egret, or white heron, with its proposed function being to attract pollinators. To understand the diversity of H. radiata plants in different areas, we examined the lip morphology and phylogeny of populations from eight habitats in the Kinki area, Japan. The complex shapes of the lips were quantified and presented as a radar chart, enabling characterization of the morphological difference among populations. Phylogenetic analysis with microsatellite markers that we generated showed the variation of genetic diversity among populations, suggesting the different degrees of inbreeding, outbreeding, and vegetative propagation. Our approach offers a basic method to characterize the morphological and genetic diversity in natural populations.     

Comparative Mitogenomics of the Genus Odontobutis (Perciformes: Gobioidei: Odontobutidae) Revealed Conserved Gene Rearrangement and High Sequence Variations

To understand the molecular evolution of mitochondrial genomes (mitogenomes) in the genus Odontobutis, the mitogenome of Odontobutis yaluensis was sequenced and compared with those of another four Odontobutis species. Our results displayed similar mitogenome features among species in genome organization, base composition, codon usage, and gene rearrangement. The identical gene rearrangement of trnS-trnL-trnH tRNA cluster observed in mitogenomes of these five closely related freshwater sleepers suggests that this unique gene order is conserved within Odontobutis. Additionally, the present gene order and the positions of associated intergenic spacers of these Odontobutis mitogenomes indicate that this unusual gene rearrangement results from tandem duplication and random loss of large-scale gene regions. Moreover, these mitogenomes exhibit a high level of sequence variation, mainly due to the differences of corresponding intergenic sequences in gene rearrangement regions and the heterogeneity of tandem repeats in the control regions. Phylogenetic analyses support Odontobutis species with shared gene rearrangement forming a monophyletic group, and the interspecific phylogenetic relationships are associated with structural differences among their mitogenomes. The present study contributes to understanding the evolutionary patterns of Odontobutidae species.     

白酒黄水中纤维素降解菌的分离鉴定及产酶活性研究

为拓展纤维素降解菌资源,以羧甲基纤维素钠（CMC-Na）为唯一碳源作初筛培养基,从浓香型白酒发酵副产物黄水中分离得到18株具有产纤维素酶能力的菌株进行纯培养。形态学、生理生化和系统发育鉴定结果显示,菌株XH01、XH04、XH05、XH18为Bacillus cereus,菌株XH34为Bacillus circulans,菌株SW01、SW05为Bacillus megaterium,菌株SW02为Bacillus endophyticus,菌株SW03、SW04为Bacillus simplex,菌株SW09、SW13为Bacillus bataviensis。菌株ZL08为Penicillium camemberti,菌株ZL13为Aspergillus fumigatus,菌株ZL04和ZL25为Penicillium chrysogenum,菌株ZL15和ZL17为Alternaria tenuissima。利用二硝基水杨酸法对菌株发酵液纤维素酶活进行研究,结果表明,菌株SW02的产酶活性较高,其羧甲基纤维素酶活为153.36 U/mL,β-葡萄糖苷酶活为126.00 U/mL,微晶纤维素酶活为17.64 U/mL,滤纸酶活为30.48 U/mL。     

川西高原牧区牦牛酸乳中的几株乳杆菌发酵特性及系统发育研究

通过感官评定和酸度测定,从川西高原自然发酵牦牛奶酸乳中分离的109 株乳酸菌中筛选出6 株发酵酸乳感官品质良好的乳杆菌,进一步研究这6 株乳杆菌的生长曲线、产酸特性、产黏特性、产乙醛特性,并采用16SrDNA 基因序列分析,初步研究其系统发育关系。结果表明：在42℃条件下,6 株乳杆菌在MRS 培养基中培养14h、在10% 的脱脂乳中培养8h 时,达到最高生长量;6 株乳杆菌发酵10% 脱脂乳凝乳时酸度都达到GB2746 -1999 的要求,凝乳黏度为1050～4900mPa·s,乙醛产量为15.11～26.64μg/mL。冷藏中菌株E1、E-5 产酸量小,后酸化能力弱。6 株乳杆菌单株凝乳冷藏中黏度在第5 天达最高,其中菌株E-1、E-5 的凝乳黏度变化小;菌株J-2、E-5 发酵乳冷藏乙醛含量在第3 天达到最高,其余菌株在第2 天达到最高。16S rDNA 基因序列的相似性分析表明,菌株4-7、E-1、E-5 之间的相似度达到99% 以上,这些菌株在系统发育树上与植物乳杆菌(L. plantarum)处于发育树的同一分支;菌株J-2 与副干酪乳杆菌(L.paracasei)处于发育树的同一分支,与代表菌株L.paracasei SM63 的相似度为97.6%;菌株4-1 和B-2 的相似度达到99%,与发酵乳杆菌(L.fermentum)处于发育树的同一分支。综合研究结果表明菌株E-1 和E-5 可用于开发酸乳发酵剂菌种。     

Comparative anatomy of the podocyte: A scanning electron microscopic study

The three-dimensional structure of the renal glomerular podocyte was comparatively analyzed with special reference to its cellular interdigitation. Kidneys of lampreys, carps, eels, xenopuses, bullfrogs, iguanas, rats, and rabbits were used as materials. Urinary and basal surfaces of podocytes were exposed by a conventional freeze-fracture method and by NaOH maceration, respectively, and subsequently examined by scanning electron microscopy. In accordance with previous reports, each podocyte consisted of a round cell body protruding into Bowman's space, four to six major processes embracing glomerular capillary, and numerous pedicels on both sides of the major processes. The podocyte pedicels exhibited uniform needle-like shapes, about 0.2 microm thick, interdigitated with those of adjoining cells along the entire length of the cell margins in all the animal species examined. This finding suggests that the fine pedicel interdigitation is a primary event in morphogenesis of the podocyte. The basal aspect of the glomerular epithelium was mosaicked with pedicels which were laid at various angles to the capillary axis, in favor of its possible role as a mechanical support of the capillary wall.