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1.
2.
Ascomata of a powdery mildew-like fungus have been found on Carpinus laxiflora in Tochigi Prefecture of Japan since 2003. The morphological and molecular characteristics of this fungus are reported, and
a new species, Erysiphe fimbriata, is proposed. It has large chasmothecia (200–250 μm in diameter) with long (up to 4–5 mm in length), fimbriate appendages
arising from the upper half of the chasmothecia and turning upward, and numerous asci (22–38 per chasmothecium). Erysiphe fimbriata is a unique fungus both genetically and morphologically. 相似文献
3.
Morphological and Genetic Characterization of <Emphasis Type="Italic">Saimiri boliviensis</Emphasis>
Eliana Ruth Steinberg Mariela Nieves Marina Sofía Ascunce Ana María Palermo Marta Dolores Mudry 《International journal of primatology》2009,30(1):29-41
The taxonomy of Saimiri is controversial because morphological characteristics, traditionally used for identification, are insufficient to distinguish
species and subspecies. Genetic studies of specimens become relevant for captive management, especially considering their
frequently unknown geographical origin. We analyzed phenotypic and genetic parameters in Saimiri spp. in Argentinean zoological gardens and biological stations to provide a more accurate taxonomic identification. We studied
27 males and 19 females of Saimiri spp. The cytogenetic analysis in mitotic metaphases corroborated a modal number of 2N = 44, XX/XY, and FN = 75 for males
and FN = 76 for females. G- and C-bands, fluorescence in situ hybridization (FISH) and the pelage coloration pattern of all the specimens corresponded to Saimiri boliviensis boliviensis. We characterized for the first time the sperm cell morphology and morphometry (mean ± SE): total length: 71.39 ± 5.40 μm;
head length: 5.71 ± 0.81 μm; head width: 3.76 ± 0.70 μm; acrosome length: 3.70 ± 0.82 μm; midpiece length: 12.20 ± 2.22 μm.
Researchers can use the characterization of the sperm morphology as another parameter for taxonomic identification that, together
with cytogenetic and molecular ones, would allow a more precise identification of individual Saimiri boliviensis boliviensis. 相似文献
4.
Summary This study reports a protocol for successful micropropagation of Decalepis arayalpathra (Joseph and Chandras) Venter. (Janakia arayalpathra Joseph and Chandrasekhran; Periplocaceae), a critically endangered and endemic ethnomedicinal plant in the southern forests of the Western Ghats which is overexploited
for its tuberous medicinal roots by the local Kani tribes. Natural regeneration is rare and conventional propagation is difficult.
Conservation of the species through micropropagation was attempted. The nodal explants of greenhouse-raised plants, were more
desirable than cotyledonary nodal explants of aseptic seedlings. The basal nodes (73%) of 12–16-wk-old greenhouse-grown plants
cultured in Murashige and Skoog (MS) medium containing 12.96 μM 6-benzyladenine (BA), 2.48 μM 2-isopentenyladenine (2-ip) and 2.68 μM α-naphthaleneacetic acid (NAA) formed 16–17 cm long unbranched robust solitary shoots in 8 wk. Cotyledonary nodal explants
cultured in the same medium showed multiple shoot formation and axillary branching. But the shoots were thin, fragile and
not suitable for mass propagation. Single nodes of a solitary shoot subcultured on MS medium containing 2.22 μM BA and 0.24 μM 2-ip together produced 9.8±0.3 nodes from 18.0±0.6 cm long shoots within 5–6 wk. The basal nodes of the shoots so formed
were repeatedly subcultured to increase the stock of propagules while the 2.5–3.0 cm terminal cuttings were used for rooting.
The best root induction (68%) and survival (86%) was achieved on half-strength MS medium supplemented with 1.07 μM NAA. Field-established plants showed uniform growth and phenotypic similarity to parental stock. 相似文献
5.
A new species of Hirsutella, H. proturicola, isolated from a subterranean proturan (Baculentulus densus; Protura, Hexapoda), is described and illustrated. Hirsutella proturicola is characterized by producing monoblastic phialides of 24–51.5 × 2.5–5 μm with a slightly roughened neck, fusiform and curved
conidia of 9–18 × 2.5–4 μm that have a truncate base and a papillate projection often capped with sheath-like mucilage, and
pluricellular, globose to subglobose chlamydospores of 21–48 × 21–41.5 μm. This species is morphologically and phylogenetically
close to H. rostrata, an acaropathogenic species, but can be distinguished from the size of the phialides and the size and shape of the conidia. 相似文献
6.
Veena Agrawal Pratima Rani Sardar 《In vitro cellular & developmental biology. Plant》2007,43(6):585-592
In vitro regeneration through somatic embryogenesis as well as organogenesis using cotyledon of a woody medicinal legume, Cassia angustifolia is reported. The cotyledons dissected from semi-mature seeds, if inoculated on Murashige and Skoog’s medium (MS) supplemented
with auxin alone or in combination with cytokinin, produced direct and indirect somatic embryos. A maximum of 14.36 ± 2.26
somatic embryos per 20 mg of explants including callus were produced in 70% cultures on MS medium with 2.5 μM benzyladenine
(BA) + 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Although the percentage of embryogenic cultures was higher (83.33%) at
10 μM 2,4-D + 1 μM BA, the average number of somatic embryos was much less (7.6 ± 0.85) at this level, whereas at 2.5 μM BA
and 5 μM 2,4-D, there was a simultaneous formation of both somatic embryos and shoots. The somatic embryos, although started
germinating on the same medium, developed into full plantlets only if transferred to MS basal with 2% sucrose. Cytokinins
alone did not induce somatic embryogenesis, but formed multiple shoots. Five micromolar BA proved optimum for recurrently
inducing shoots in the competent callus with a maximum average of 12.04 ± 2.10 shoots and shoot length of 2.26 ± 0.03 cm.
Nearly 91.6% shoots (2–2.5 cm in size) organized an average of 5.12 ± 0.58 roots on half strength MS + 10 μM indole-3-butyric
acid. All the plantlets have been transferred successfully to soil. Types of auxin and its interaction with cytokinin significantly
influenced somatic embryogenesis. 相似文献
7.
Some bacteria were isolated from Dendroctonus micans and its specific predator, Rhizophagus grandis. Six bacteria from D. micans were identified as Bacillus pumilus, Enterobacter intermedius, Citrobacter freundii, Cellulomonas flavigena, Microbacterium liquefaciens and Enterobacter amnigenus, three bacteria from R. grandis as Klebsiella pneumoniae, Pantoea agglomerans and Serratia grimesii, on the basis of fatty acid methyl ester analysis and carbon utilization profile by using Microbial Identification and Biolog
Microplate Systems. Their insecticidal effects were tested on larvae and adults of D. micans. 相似文献
8.
Wenbing Li Longjiang Yu Pengpeng Zhou Min Zhu 《World journal of microbiology & biotechnology》2007,23(10):1489-1492
Summary A helical shaped bacterium capable of producing magnetosomes, designated WM-1, was isolated from freshwater sediment through
an improved isolated method that combined magnetic separation and the “race track” method. The strain WM-1 was Gram-negative,
0.2–0.4 μm in diameter and 3–4 μm in length. The strain WM-1 was identified as genus Magnetospirillum in the α-Proteobacteria according to the sequence analysis of the 16S rDNA, the morphology and physiological characteristics.
The shape of the magnetosomes in WM-1was cuboidal by electron microscopy. Statistical analysis of WM-1 magnetosome crystals
showed that the average number of magnetosomes in a WM-1 bacterium was 8 ± 3.4, and the average length was 54 ± 12.3 nm, and
the average width was 43 ± 10.9 nm. 相似文献
9.
On the family Brassicaceae, the causal agent responsible for downy mildew disease was originally regarded as a single species,
Peronospora parasitica (now under Hyaloperonospora), but it was recently reconsidered to consist of many distinct species. In this study, 11 specimens of Peronospora
drabae and P. norvegica parasitic on the genus Draba were investigated morphologically and molecularly. Pronounced differences in conidial sizes (P. drabae: 14–20 × 12.5–15.5 μm; P. norvegica: 20–29 × 15.5–22 μm) and 7.8% sequence distance between their ITS1-5.8S-ITS2 rDNA sequences confirmed their status as distinct
species. Based on ITS phylogeny and morphology (monopodially branching conidiophores, flexuous to sigmoid ultimate branchlets,
hyaline conidia and lobate haustoria), the two species unequivocally belong to the genus Hyaloperonospora and not to Peronospora to which they were previously assigned. Therefore, two new combinations, Hyaloperonospora drabae and H. norvegica, are proposed. The two taxa are illustrated and compared using the type specimen for H. norvegica and authentic specimens for H. drabae, which is lectotypified. 相似文献
10.
Summary An efficient and rapid micropropagation system was developed for a food and medicinally important endangered shrub, Decalepis hamiltonii (‘swallow root’), through shoot multiplication. The influence of 2.5–7.5 μM isopentenyladenine (2iP), 4.4–17.7 μM 6-benzyladenine, 2.3–4.7 μM kinetin, 2.8–6.8 μM thidiazuron, and 2.3–11.4 μM zeatin alone and in combination with 0.3–0.9 μM indole-3-acetic acid (IAA) on in vitro multiple shoot production was studied. The maximum number of multiple shoots (6.5±0.4) was induced from shoot tips cultured
on agar-based Murashige and Skoog (MS) medium containing 4.9 μM 2iP. But, both zeatin (9.1 μM) and kinetin (4.7 μM) in combination with IAA (0.6 μM) were able to produce a maximum of 5.0±0.4 and 5.1±0.4 multiple shoots, respectively. Further elongation of shoots and adventitious
shoot formation was obtained on medium containing 2.5 μM 2iP and 0.3 μM gibberellic acid. Elongated shoots were separated and rooted on MS medium supplemented with 9.8μM indole-3-butyric acid (IBA) and various phenolic compounds within 5–6 wk. Phloroglucinol and salicylic acid interaction with
IBA stimulated in vitro rooting of shoots. Successful field transfer was achieved in rooted plantlets. 相似文献
11.
An efficient protocol was developed for micropropagation of an economically important timber-yielding multipurpose tree, Pterocarpus marsupium Roxb. Multiple shoots were induced from cotyledonary nodes (CNs) derived from 18-d-old axenic seedlings on Murashige and
Skoog (MS) medium supplemented with thidiazuron (TDZ) (0.1–10 μM). The highest shoot regeneration frequency (90%) and maximum
number (15.2 ± 0.20) of shoots per explant was recorded on MS medium amended with 0.4 μM TDZ. Continuous presence of TDZ inhibited
shoot elongation. In the primary medium, TDZ-initiated cultures were transferred to the secondary medium supplemented with
another cytokinin, 6-benzyladenine (BA), for shoot growth and elongation. Maximum (90%) shoot elongation with an average shoot
length of 5.4 ± 0.06 cm was observed at 5 μM BA. To further enhance the number of shoots per explant, mother tissue was repeatedly
subcultured on fresh shoot induction medium after each harvest of newly formed shoots. Thus, by adopting this strategy, an
average of 44 shoots per explant could be obtained. About 65% of in vitro regenerated shoots produced a maximum number (4.4 ± 0.2) of roots per shoot by a two-step culture procedure employing pulse
treatment and subsequent transfer of treated shoots to a low concentration of 0.2 μM indole-3-butyric acid along with phloroglucinol
(3.96 μM). The in vitro-raised plantlets were successfully acclimatized first under culture room conditions, then to greenhouse with 70% survival
rate. 相似文献
12.
The genus Dierama comprises plants with a potential to be developed as ornamentals. D. erectum seeds were decontaminated and germinated on 1/10th strength Murashige and Skoog (Physiol Plant 15:473–497, 1962) (MS) media
without plant growth regulators or sucrose. In an experiment investigating the effects of 6-benzyladenine (BA), meta-Topolin (mT), kinetin (KIN) and zeatin (Z) with or without α-naphthaleneacetic acid (NAA), the highest shoot number per hypocotyl (4.20 ± 0.51)
was obtained from MS medium supplemented with 1.0 μM Z after 8 weeks. This was followed by a combination of 2.0 μM KIN and
2.0 μM NAA with 3.67 ± 0.81 shoots per explant. BA treatments produced 3.20 ± 0.22 shoots per hypocotyl explant when 2.0 μM
was combined with 1.0 μM NAA, while mT gave 3.09 ± 0.99 shoots per explant when 2.0 μM mT was combined with 2.0 μM NAA. Adventitious shoot regeneration was optimised when shoots were grown under a 16-h photoperiod
at 100 μmol m−2 s−1 on MS medium supplemented with 1.0 μM BA. This resulted in an average of 12.73 ± 1.03 shoots per hypocotyl explant. Various
concentrations of ancymidol, activated charcoal and sucrose did not promote in vitro corm formation of this species. Plants
rooted successfully after 8 weeks on MS medium supplemented with 1.0 μM indole-3-butyric acid (IBA) and had an average root
number of 2.73 ± 0.40. After 2 months of acclimatisation, plants had formed corms. The largest corms (of diameter 0.45 ± 0.03 cm)
were produced in plants pre-treated with 0.5 μM IBA. The highest plant survival percentage of 73% was also associated with
this treatment. 相似文献
13.
An increasing number of studies reveal that ticks and their hosts are infected with multiple pathogens, suggesting that coinfection
might be frequent for both vectors and wild reservoir hosts. Whereas the examination of associations between coinfecting pathogen
agents in natural host–vector–pathogen systems is a prerequisite for a better understanding of disease maintenance and transmission,
the associations between pathogens within vectors or hosts are seldom explicitly examined. We examined the prevalence of pathogen
agents and the patterns of associations between them under natural conditions, using a previously unexamined host–vector–pathogen
system—green lizards Lacerta viridis, hard ticks Ixodes ricinus, and Borrelia, Anaplasma, and Rickettsia pathogens. We found that immature ticks infesting a temperate lizard species in Central Europe were infected with multiple
pathogens. Considering I. ricinus nymphs and larvae, the prevalence of Anaplasma, Borrelia, and Rickettsia was 13.1% and 8.7%, 12.8% and 1.3%, and 4.5% and 2.7%, respectively. The patterns of pathogen prevalence and observed coinfection
rates suggest that the risk of tick infection with one pathogen is not independent of other pathogens. Our results indicate
that Anaplasma can play a role in suppressing the transmission of Borrelia to tick vectors. Overall, however, positive effects of Borrelia on Anaplasma seem to prevail as judged by higher-than-expected Borrelia–Anaplasma coinfection rates. 相似文献
14.
Summary We describe an in vitro propagation protocol for Zingiber petiolatum (Holttum), I. Theilade, a rare species from the southern part of Thailand. Fruits were surface-sterilized and seeds germinated
on Murashige and Skoog medium (MS) medium supplemented with 3% sucrose. Three-month-old seedlings were used as initial plant
material for in vitro propagation. Terminal buds of the plants were inoculated on MS medium containing 6-benzylaminopurine (BA; 2.2–35.5 μM) alone or in combination with 1-naphthaleneacetic acid (0.5 μM). Eight weeks after inoculation, the cultures were transferred to MS medium without plant growth regulators for 4wk. The
cultures transferred from MS medium with 17.8 μM BA revealed the highest shoot induction rate of 6.1±0.7 shoots per explant. Rooting was spontaneously achieved in MS medium
without plant growth regulators. Rooted plants were successfully transplanted to soil. 相似文献
15.
Summary An efficient and reproducible procedure for the large-scale propagation of Pseudoxytenanthera stocksii is described. High-frequency multiple shoot induction was achieved from nodal shoot segments collected from superior/elite
genotypes on Murashige and Skoog (MS) liquid medium supplemented with 1-naphthaleneacetic acid (NAA; 2.68 μM) and 6-benzylaminopurine (BA; 4.40 μM) at 28±1°C and 60 μmol m−2 s−1 light intensity under 12h photoperiod. In vitro-differentiated shoots were multiplied on MS liquid medium fortified with NAA (2.68 μM), BA (2.21 μM) and additives: ascorbic acid (283.93 μM), citric acid (118.10 μM), cysteine (104.04 μM), and glutamine (342.24 μM). Subculturing was carried out every 2wk on fresh shoot multiplication medium. About 125–150 shoots per culture flask were
harvested within 45–50d. In vitro-differentiated shoot clumps (three or four shoots) were successfully rooted on half-strength MS basal liquid medium with
indole-3-butyric acid (4.90 μM), BA (0.44 μM), and additives. This is the first report where in vitro- and in vivo-(through tillers) raised clonal plants were acclimatized and established in the field, where they exhibited normal growth. 相似文献
16.
17.
Echinorhynchus hexagrammi Baeva, 1965 is redescribed on the basis of specimens collected from the saffron cod Eleginus gracilis (Tilesius) in Akkeshi Bay (western North Pacific) off Hokkaido, Japan. Eighteen museum specimens deposited as E. salmonis Müller, 1784 from Japanese coastal waters were also re-examined and re-identified as E. hexagrammi. Hexagrammos stelleri Tilesius, Hemitripterus villosus (Pallas), Podothecus sachi (Jordan & Snyder), Sebastes oblongus Günther and Verasper moseri Jordan & Gilbert are recognised as new hosts for E. hexagrammi. This acanthocephalan can be distinguished from three morphologically similar species, E. gadi Zoega in Müller, 1776, E. laurentianus Ronald, 1957 and E. salmonis, by the possession of the following characters: 12–16 (usually 14) rows of hook on the proboscis, a proboscis width of 170–240 μm
in males and 195–270 μm in females, a hook root length of 35–45 μm in males and 40–50 μm in females, and linearly or almost
linearly arranged cement glands in males. 相似文献
18.
Vishal Gupta Manoj Kumar Puja Kumari C. R. K. Reddy Bhavanath Jha 《Journal of applied phycology》2011,23(2):209-218
This study reports on the optimization of protoplast yield from two important tropical agarophytes Gracilaria dura and Gracilaria verrucosa using different cell-wall-degrading enzymes obtained from commercial sources. The conditions for achieving the highest protoplast
yield was investigated by optimizing key parameters such as enzyme combinations and their concentrations, duration of enzyme
treatment, enzyme pH, mannitol concentration, and temperature. The significance of each key parameter was also further validated
using the statistical central composite design. The enzyme composition with 4% cellulase Onozuka R-10, 2% macerozyme R-10,
0.5% pectolyase, and 100 U agarase, 0.4 M mannitol in seawater (30‰) adjusted to pH 7.5 produced the highest protoplast yields
of 3.7 ± 0.7 × 106 cells g−1 fresh wt for G. dura and 1.2 ± 0.78 × 106 cells g−1 fresh wt for G. verrucosa when incubated at 25°C for 4–6 h duration. The young growing tips maximally released the protoplasts having a size of 7–15 μm
in G. dura and 15–25 μm in G. verrucosa, mostly from epidermal and upper cortical regions. A few large-size protoplasts of 25–35 μm, presumably from cortical region,
were also observed in G. verrucosa. 相似文献
19.
Haptoglossa spp. (Lagenidiales, Oomycetes) have been known to parasitize microscopic animals by means of a "gun" cell that shoots an
infection cell, named the sporidium, into the body of the animal. A thallus grown from the sporidium changes into a zoosporangium
at maturation to produce a number of zoospores that encyst after a swarming period, and the resulting cysts germinate to produce
gun cells. In Haptoglossa zoospora, endoparasitic in nematodes, the cysts of primary zoospores that swam for about 5 min did not develop gun cells but produced
secondary zoospores that swam for about 3 h. After encystment of the secondary zoospores, each secondary cyst germinated to
produce a gun cell. In the present study, the secondary zoospores of the genus Haptoglossa could be recorded with a videocassette recorder for the first time. The videocassette recording also revealed the infection
of a nematodes by H. zoospora and H. heterospora to be composed of two steps of injection of a sporidium by the gun cell, in which the gun cell came in contact with the cuticle
of a nematode and produced a spherical adhesorium on the tip of the cell in 0.07–0.1 s in both species. The adhesorium was
∼2 μm in H. zoospora and ∼4 μm in H. heterospora. When the adhesorium infiated to full size, it shot the sporidium into the nematode's body in 0.5–0.65 s and in 0.2–0.5 (or
rarely 1.0) s in H. zoospora and H. heterospora, respectively. After shooting, the empty gun cell with an empty cyst case was separated from the cuticle immediately in both
species.
Received: October 3, 2001 / Accepted: December 13, 2001 相似文献
20.
In this study, we report the cloning, recombinant expression, and biochemical characterization of a heat-stable CMP-N-acylneuraminic acid (NeuAc) synthetase from Clostridium thermocellum ATCC 27405. A high throughput electrospray ionization mass spectrometry (ESI-MS)-based assay demonstrates that the enzyme
has an absolute requirement for a divalent cation for activity and reaches maximum activity in the presence of 10 mM Mn2+. The enzyme is active at pH 8–13 in Tris–HCl buffer and at 37–60 °C, and maximum activity is observed at pH 9.5 and 50 °C
in the presence of 0.2 mM dithiothreitol. In addition to NeuAc, the enzyme also accepts the analog N-glycolylneuraminic acid (NeuGc) as a substrate. The apparent Michaelis constants for cytidine triphosphate and NeuAc or NeuGc
are 240 ± 20, 130 ± 10, and 160 ± 10 μM, respectively, with corresponding turnover numbers of 3.33, 2.25, and 1.66 s−1, respectively. An initial velocity study of the enzymatic reaction indicates an ordered bi–bi catalytic mechanism. In addition
to demonstration of a thermostable and substrate-tolerant enzyme, confirmation of the biochemical function of a gene for CMP-NeuAc
synthetase in C. thermocellum also opens the question of the biological function of CMP-NeuAc in such nonpathogenic microorganisms. 相似文献