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1.
Chitwadee Phithakrotchanakoon Ratama Daduang Arinthip Thamchaipenet Thidarat Wangkam Toemsak Srikhirin Lily Eurwilaichitr Verawat Champreda 《Applied microbiology and biotechnology》2009,82(1):131-140
A polyhydroxyalkanote depolymerase gene from Thermobifida sp. isolate BCC23166 was cloned and expressed as a C-terminal His6-tagged fusion in Pichia pastoris. Primary structure analysis revealed that the enzyme PhaZ-Th is a member of a proposed new subgroup of SCL-PHA depolymerase
containing a proline–serine repeat linker. PhaZ-Th was expressed as two glycosylated forms with apparent molecular weights
of 61 and 70 kDa, respectively. The enzyme showed esterase activity toward p-nitrophenyl alkanotes with V
max and K
m of 3.63 ± 0.16 μmol min−1 mg−1 and 0.79 ± 0.12 mM, respectively, on p-nitrophenyl butyrate with optimal activity at 50–55°C and pH 7–8. Surface plasmon resonance (SPR) analysis demonstrated that
PhaZ-Th catalyzed the degradation of poly-[(R)-3-hydroxybutyrate] (PHB) films, which was accelerated in (R)-3-hydroxyvalerate copolymers with a maximum degradation rate of 882 ng cm−2 h−1 for poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (12 mol% V). Surface deterioration, especially on the amorphous regions of PHB films
was observed after exposure to PhaZ-Th by atomic force microscopy. The use of P. pastoris as an alternative recombinant system for bioplastic degrading enzymes in secreted form and a sensitive SPR analytical technique
will be of utility for further study of bioplastic degradation. 相似文献
2.
C. Douglas Boyette Mark A. Weaver Robert E. Hoagland Kenneth C. Stetina 《World journal of microbiology & biotechnology》2008,24(11):2721-2726
A mycelial formulation of the fungus Myrothecium verrucaria (IMI 361690) containing 0.20% Silwet L-77 surfactant was found to be highly efficacious in controlling the exotic invasive
weed kudzu. The mycelium can be rapidly (48–72 h) produced in several media, including an inexpensive soy flour–corn meal
medium. Mycelial yields were 2, 10, and 25 g dry weight l−1 in Czapek-Dox, Richard’s V-8, and soy flour–corn meal media, respectively. Scale-up production in soy flour–corn meal medium
using laboratory fermenters (10–25 l), resulted in a mycelial formulation that caused 90% mortality of naturally-occurring
mature (0.9–1.0 m in height) kudzu within 48 h after application in field experiments. HPLC analyses revealed that the mycelium
produced in this liquid culture contained no detectable amounts of the trichothecene mycotoxins roridin A and verrucarin A
(limit of detection 2 μg ml−1). This has resulted in a safer, yet effective bioherbicidal product. We anticipate that these findings should improve the
probability of EPA registration and subsequent commercial development of this bioherbicide. 相似文献
3.
Fawzeia H. Elmhalli Katinka Pålsson Jan Örberg Thomas G. T. Jaenson 《Experimental & applied acarology》2009,48(3):251-262
The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs
at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate
increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results
obtained by methods A, C and E, the LC50 range was 0.035–0.037 mg PMD/cm2 and the LC95 range was 0.095–0.097 mg PMD/cm2 at 4 h of exposure; the LT50 range was 2.1–2.8 h and the LT95 range was 3.9–4.2 h at 0.1 mg PMD/cm2. To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm2) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed
that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic
to nymphs of I. ricinus and may be useful for tick control. 相似文献
4.
Identification and Quantification of Several Mammalian Steroid Hormones in Plants by UPLC-MS/MS 总被引:1,自引:0,他引:1
Radim Simerský Ondřej Novák David A. Morris Vladimír Pouzar Miroslav Strnad 《Journal of Plant Growth Regulation》2009,28(2):125-136
We have developed an effective method for the isolation, identification, and quantification of several mammalian steroid hormones
and their metabolites in different plant tissues. The purification protocol was based on solid-phase extraction (SPE) combined
with immunoaffinity chromatography (IAC) using immobilized generic polyclonal anti-Δ4-3-keto-steroid antibodies covalently bound to Affi-Gel 10 sorbent. The antibodies were characterized by means of enzyme-linked
immunosorbent assay (ELISA). The detection limit of the ELISA was 6.0 × 10−10 mol L−1 and cross-reactivity with most Δ4-3-keto-steroids was very high as predicted (68–122%). The IAC allowed fast, single-step purification of different plant extracts
prior to analysis by ultra-performance liquid chromatography-electrospray tandem mass spectrometry [UPLC-ESI(+)-MS/MS]. In
multiple-reaction-monitoring (MRM) mode, the detection limit of the method for most of the steroids analyzed was close to
10 fmol and the response was linear up to 50 pmol injected. The analytical accuracy was validated using tobacco leaf samples
spiked with known amounts of authentic and deuterium-labeled standards. The newly developed method was capable of detecting
and quantifying at least 12 specified steroid compounds in plant extracts. In the analyzed extracts from three plant species,
that is, common foxglove (Digitalis purpurea L.), tobacco (Nicotiana tabacum L.), and elecampane inula (Inula helenium L.), four endogenous steroids were detected, identified, and quantified. Progesterone was found in all three plants at concentrations
comparable to those reported in previous studies. Three other steroids, androstendione, 17α-hydroxyprogesterone, and 16-dehydroprogesterone,
were identified for the first time in plant extracts. 17α-Hydroxyprogesterone and 16-dehydroprogesterone occurred at significant
concentrations in D. purpurea, whereas androstendione was found in N. tabacum and I. helenium but not in D. purpurea. 相似文献
5.
The effect of fungal infection on the reproductive potential of two-spotted spider mite, Tetranychus urticae, was evaluated as part of the full biocontrol potential of three entomopathogenic fungi by modeling of fecundity probability.
Female mites (≤2-day-old) on leaves were exposed to the sprays of Beauveria bassiana, Paecilomyces fumosoroseus and Metarhizium anisopliae at the concentrations of 1.13 × 103, 1.55 × 103 and 0.95 × 103 deposited conidia mm−2 and then individually reared at 25°C and 12:12 L:D for oviposition. Mite mortalities 10 days after spraying were 73.1, 75.4
and 67.9% in the fungal treatments versus 15.5% in control. On average, females infected by the three fungal species survived
5.8, 6.2 and 6.3 days, and laid 3.1, 4.0 and 4.0 eggs per capita, respectively. These were 3–4 fold lower than the control
fecundity at 12.3. The cumulative probabilities [P(m ≤ N)] for the counts of infected and non-infected (control) females laying m eggs per capita (m ≤ N) during 10 days fit very well the equation P(m ≤ N) = 1/[1 + exp(a + bm)] (r
2 ≥ 0.98), yielding a solution to the probability for the female mites to achieve a specific fecundity {P(m ≤ N)−P[m ≤ (N − 1)]}. Consequently, the infected mites had 71–78% chance to lay ≤5 eggs per capita but only 5–8% to deposit >10 eggs despite
some variation among the tested fungi. In contrast, the chances for the non-infected mites to achieve the low and high fecundities
were 23 and 55%. The fitted probabilities provide a full coverage of the fecundity potential of infected versus non-infected
mites and are more informative than the mean fecundities. 相似文献
6.
Shainn-Wei Wang William J. McCarthy 《In vitro cellular & developmental biology. Animal》1997,33(4):315-323
Summary A sensitive lactate dehydrogenase (LDH) assay was modified to determine the cytolytic activity of Bacillus thuringiensis CryIC and CryIAc delta endotoxins to viable collagenase-dissociated midgut epithelial cells (MEC) from larvae of Spodoptera frugiperda and Spodoptera exigua. The MEC preparations from these Spodoptera sp. consisted predominantly of columnar cells (65–75%) and goblet cells (25–35%). Time course microscopy experiments indicated
that only the columnar cells became swollen during CryIC toxin incubation. Also, comparative cytotoxicity studies were run
with cell lines of nonmidgut origin established from S. frugiperda (SF21AE) and S. exigua (SEUCR1A). Optimum conditions for the cytotoxicity assay were similar for MEC and cell lines of both species, and were met
in an assay in which 0.1-ml cell concentrations (8.5±0.5×104 cells) were incubated with toxin dilutions (0.01–20 μg) for 1 h at 24° C at a final pH of 7.8.
The Spodoptera sp. MEC were twofold more sensitive to CryIC (68% lysis) than CryIAc (32% lysis) at optimum toxin levels (2.5–5 μg). Also,
the SEUCR1A cells were more sensitive (2.3-fold) to CryIC (70% lysis) than CryIAc (30% lysis) at optimum toxin levels of 5–10
μg. The SF21AE cells, however, were twofold less sensitive to CryIC (30% lysis) than SEUCR1A cells and response to CryIAc
and CryIC was similar.
Immunoblot analysis of either Spodoptera sp. MEC or brush border membrane vesicles (BBMV) identified seven CryIC binding proteins with molecular mass of 137, 120,
115, 68, 65, 63, and 45 kDa. Occasionally, a 148-kDa protein band was observed. The CryIAc toxin bound to two proteins on
MEC and BBMV with molecular mass of 137 and 120 kDa. 相似文献
7.
Ruixiang Zhao Junliang Sun Peter Torley Dahong Wang Shengyang Niu 《World journal of microbiology & biotechnology》2008,24(8):1349-1354
Lactobacillus acidophilus, as a probiotic, is widely used in many functional food products. Microencapsulation not only increases the survival rate
of L. acidophilus during storage and extends the shelf-life of its products, but also optimal size microcapsule makes L. acidophilus have an excellent dispersability in final products. In this paper, L. acidophilus was microencapsulated using spray drying (inlet air temperature of 170°C; outlet air temperature of 85–90°C). The wall materials
used in this study were β-cyclodextrin and acacia gum in the proportion of 9:1 (w/w), and microcapsules were prepared at four
levels of wall materials (15, 20, 25 and 30% [w/v]) with a core material concentration of 6% (v/v). The microcapsule diameters
were measured by Malvern’s Mastersizer-2000 particle size analyzer. The results showed that the particle diameters of microcapsule
were mostly within 6.607 μm and 60.256 μm and varied with 2.884–120.226 μm (the standard smaller microcapsule designated as
<350 μm). Through comparison of microcapsule size and uniformity with different concentration of wall materials, we concluded
that the optimal concentration of wall material was 20% (w/v), which gave microcapsule with a relatively uniform size (averaging
22.153 μm), and the number of surviving encapsulated L. acidophilus was 1.50 × 109 c.f.u./ml. After 8 weeks storage at 4°C, the live bacterial number was above 107 c.f.u./ml, compared with unencapsulated L. acidophilus, 104–105 c.f.u./ml. Through the observation of scanning electron microscopy, we found that the shapes of microcapsule were round and
oval, and L. acidophilus cells located in the centre of microcapsule. 相似文献
8.
Mohammad K. Khalesi H. H. Beeftink R. H. Wijffels 《Marine biotechnology (New York, N.Y.)》2009,11(4):488-494
The branching zooxanthellate soft coral Sinularia flexibillis releases antimicrobial and toxic compounds with potential pharmaceutical importance. As photosynthesis by the symbiotic algae
is vital to the host, the light-dependency of the coral, including its specific growth rate (μ day−1) and the physiological response to a range of light intensities (10–1,000 μmol quanta m−2 s−1) was studied for 12 weeks. Although a range of irradiances from 100 to 400 μmol quanta m−2 s−1 was favorable for S. flexibilis, based on chlorophyll content, a light intensity around 100 μmol quanta m−2 s−1 was found to be optimal. The contents of both zooxanthellae and chlorophyll a were highest at 100 μmol quanta m−2 s−1. The specific budding rate showed almost the same pattern as the specific growth rate. The concentration of the terpene flexibilide,
produced by this species, increased at high light intensities (200–600 μmol quanta m−2 s−1). 相似文献
9.
The tdh (thermostable direct hemolysin) gene occurs in some strains of Vibrio species. All tdh genes are flanked by insertion sequence-like elements (ISV). All previous attempts have failed to detect transposition of
these ISVs. In this work, we have built a transposition detection system in E. coli and succeeded in detecting the transposition of an insertion sequence-like element at a frequency of Kmr mutants of 7.2 × 10−6. A specific flanking sequence (5′-Py-Pu-3′) was found on either side of the target duplication. 相似文献
10.
Da-Chun Zhuang Yi-Guang Chen Yu-Qin Zhang Shu-Kun Tang Xiao-Lei Wu Zhou-Cai Tan Wen-Jun Li Xiao-Long Cui 《Antonie van Leeuwenhoek》2009,96(3):295-301
A novel Gram-negative, catalase- and oxidase-positive, non-sporulating, rod-shaped, aerobic bacterium, designated strain JSM
078120T, was isolated from sea water collected from a tidal flat of Naozhou Island, South China Sea. Growth occurred with 1–15% (w/v)
total salts (optimum, 2–4%), at pH 6.0–10.0 (optimum, pH 7.5) and at 4–35°C (optimum, 25–30°C). The major cellular fatty acids
were C18:1
ω9c, C16:0, C12:0 3-OH and C16:1
ω7c. The predominant respiratory quinone was ubiquinone Q-9, and the genomic DNA G + C content was 60.6 mol%. Phylogenetic analysis
based on 16S rRNA gene sequences indicated that strain JSM 078120T should be assigned to the genus Marinobacter, being related most closely to the type strains of Marinobacter segnicrescens (sequence similarity 98.2%), Marinobacter bryozoorum (97.9%) and Marinobacter gudaonensis (97.6%). The sequence similarities between the novel isolate and the type strains of other recognized Marinobacter species ranged from 96.7 (with Marinobacter salsuginis) to 93.3% (with Marinobacter litoralis). The levels of DNA–DNA relatedness between strain JSM 078120T and the type strains of M. segnicrescens, M. bryozoorum and M. gudaonensis were 25.3, 20.6 and 18.8%, respectively. The combination of phylogenetic analysis, DNA–DNA relatedness, phenotypic characteristics
and chemotaxonomic data supported the view that strain JSM 078120T represents a novel species of the genus Marinobacter, for which the name Marinobacter zhanjiangensis sp. nov. is proposed. The type strain is JSM 078120T (= CCTCC AB 208029T = DSM 21077T = KCTC 22280T).
The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain JSM 078120T is FJ425903. 相似文献
11.
The electrochemical detection of Escherichia coli β-d-glucuronidase activity as a means of monitoring water pollution by faecal material was investigated using separate Moraxella- and Pseudomonas putida-modified glassy carbon electrodes. The former was more sensitive and selective. The Moraxella-modified biosensor was 100 times more rapid and sensitive than the spectrophotometric detection of β-d-glucuronidase activity. The experimental limit of detection of the biosensor was two c.f.u. per 100 ml polluted water sample
within 20 min. The biosensor gave a linear response to commercial β-d-glucuronidase concentration between 0.2 ng and 2 μg ml−1. The biosensor detected activity of β-d-glucuronidase from viable but non-culturable (VBNC) cells and can therefore serve as a presence or absence device for rapid
water quality monitoring. 相似文献
12.
Microbial and decomposition efficiencies of monoculture and polyculture vermireactors,based on epigeic and anecic earthworms 总被引:2,自引:0,他引:2
Surindra Suthar 《World journal of microbiology & biotechnology》2008,24(8):1471-1479
Efforts have been made to evaluate the microbial and decomposition efficiency of three different vermireactors: (i) polyculture
(introducing equal numbers of anecic and epigeic earthworms), (ii) monoculture (anecic) and (iii) monoculture (epigeic), designed
by using earthworms of two different ecological categories i.e. anecic (Lampito mauritii Kinberg) and epigeic (Eisenia fetida (Savigny)). The microbial load of vermireactors was measured through substrate-induced respiration rate (SIR), microbial
biomass N content and rate of dehydrogenase activity, while mineralization rate was evaluated measuring some chemical parameters
of the substrate. Earthworms caused a decrease (as compared to initial value) in pH (41.9–80.7%), organic C (10.3–14.2%) and
C:N ratio (41.9–80.7%) and an increase in total N (29.1–58.8%), NH4-N (876.1–1485.7%), NO3-N (29081.8–56792.6%), available P (16–19.4%) and exchangeable K (9.8–13.5%) contents of the substrate. The mineralization
efficiency of the reactors was in the order: polyculture (epigeic + anecic) > monoculture (anecic) > monoculture (epigeic).
The polyculture reactor showed the maximum rate of SIR (2.91 ± 0.2 mg CO2 g−1 substrate), microbial biomass N (3108.1 ± 289.2 mg N g−1 substrate), and dehydrogenase activity (2453.3 ± 379.8 μg g−1 substrate 24 h), while in the monoculture (epigeic) the lowest values of the same parameters were observed. It is concluded
that the observed differences among reactors were due to different feeding behaviour and niche structures of epigeic and anecic
earthworms. Data suggests that burrowing earthworms in waste-decomposing-system not only enhance the microbial efficiencies,
but at the same time also accelerate the organic matter mineralization in a vermireactor. However, most of the previous studies
were based on monoculture reactors (using epigeic earthworms) which have been recommended for waste decomposition operations,
but this study revealed that polyculture vermicomposting (adding of burrowing worms with epigeic earthworms in vermicomposting
system) might be beneficial for rapid decomposition of organic wastes. 相似文献
13.
Ö. Şimşek N. Akkoç A. H. Çon F. Özçelik P. E. J. Saris Mustafa Akçelik 《Journal of industrial microbiology & biotechnology》2009,36(6):863-871
Nisin production in continuous cultures of bioengineered Lactococcus lactis strains that incorporate additional immunity and regulation genes was studied. Highest nisin activities were observed at
0.2 h–1 dilution rate and 12.5 g l–1 fructose concentration for all strains. Recombinant strains were able to produce greater amounts of nisin at dilution rates
below 0.3 h−1 compared to the control strain. However, this significant difference disappeared at dilution rates of 0.4 and 0.5 h–1. For the strains LL27, LAC338, LAC339, and LAC340, optimum conditions for nisin production were determined to be at 0.29,
0.26, 0.27, and 0.27 h–1 dilution rates and 11.95, 12.01, 11.63, and 12.50 g l–1 fructose concentrations, respectively. The highest nisin productivity, 496 IU ml–1 h–1, was achieved with LAC339. The results of this study suggest that low dilution rates stabilize the high specific nisin productivity
of the bioengineered strains in continuous fermentation. Moreover, response surface methodology analysis showed that regulation
genes yielded high nisin productivity at wide ranges of dilution rates and fructose concentrations. 相似文献
14.
The chemical composition of rainwater is altered upon its passage through tree canopies. In order to investigate how rainwater
chemistry is affected by canopy-dependent processes in characteristic forest types of Northwest German sandy lowland regions
– oak–birch-forests, Betula pubescens Ehrh. swamp forests, and stands of Pinus sylvestris L. – comparative studies on the chemical composition of throughfall were carried out at seven forest sites, situated in close
proximity within a nature reserve. Additionally, rainwater was sampled at three heathland sites for analysis of open-field
precipitation and at three sites along an oak–birch-forest edge. Throughfall concentrations of most of the parameters analysed
were significantly higher than open-field concentrations, especially with regard to electric conductivity, NH4-N, K+, and KMnO4-index. Ion concentrations in throughfall were the lowest in a 10-year-old stand of Betula pendula Roth. and Pinus sylvestris and in a Betula pubescens swamp forest and were highest beneath a stand of Pinus sylvestris. Except for Na+, Cl−, and NO3−, ion concentrations in both throughfall and open-field precipitation increased during the growing season (May–October). In
throughfall, Ca2+, Mg2+, K+, and Mn2+ were strongly correlated. Enrichment ratios between throughfall and open-field deposition varied among sites and elements
and were the highest for K‰+, Mg2‰+, and Mn2‰+. Estimates of canopy leaching indicated high leaching rates of K‰+ and Mn2‰+ and moderate leaching of Mg2‰+. The contribution of foliar leaching to throughfall deposition was higher at the deciduous than at the coniferous stands. 相似文献
15.
Okeke BC 《Journal of industrial microbiology & biotechnology》2008,35(12):1571-1579
Pollution of terrestrial surfaces and aquatic systems by hexavalent chromium, Cr(VI), is a worldwide public health problem.
A chromium resistant bacterial isolate identified as Exiguobacterium sp. GS1 by 16S rRNA gene sequencing displayed high rate of removal of Cr(VI) from water. Exiguobacterium sp. GS1 is 99% identical to Exiguobacterium acetylicum. The isolate significantly removed Cr(VI) at both high and low concentrations (1–200 μg mL−1) within 12 h. The Michaelis–Menten K
m
and V
max for Cr(VI) bioremoval were calculated to be 141.92 μg mL−1 and 13.22 μg mL−1 h−1, respectively. Growth of Exiguobacterium sp. GS1 was indifferent at 1–75 μg mL−1 Cr(VI) in 12 h. At initial concentration of 8,000 μg L−1, Exiguobacterium sp. GS1 displayed rapid bioremoval of Cr(VI) with over 50% bioremoval in 3 h and 91% bioremoval in 8 h. Kinetic analysis
of Cr(VI) bioremoval rate revealed zero-order in 8 h. Exiguobacterium sp. GS1 grew and significantly reduced Cr(VI) in cultures containing 1–9% salt indicating high salt tolerance. Similarly
the isolate substantially reduced Cr(VI) over a wide range of temperature (18–45 °C) and initial pH (6.0–9.0). The T
opt and initial pHopt were 35–40 °C and 7–8, respectively. Exiguobacterium sp. GS1 displayed a great potential for bioremediation of Cr(VI) in diverse complex environments. 相似文献
16.
Malaysia is the world’s leading producer of palm oil products that contribute US$ 7.5 billion in export revenues. Like any
other agro-based industries, it generates waste that could be utilized as a source of organic nutrients for microalgae culture.
Present investigation delves upon Isochrysis sp. culture in POME modified medium and its utilization as a supplement to Nanochloropsis sp. in rotifer cultures. The culture conditions were optimized using a 1 L photobioreactor (Temp: 23°C, illumination: 180 ∼ 200 μmol
photons m−2s−1, n = 6) and scaled up to 10 L outdoor system (Temp: 26–29°C, illumination: 50 ∼ 180 μmol photons m−2s−1, n = 3). Algal growth rate in photobioreactor (μ = 0.0363 h−1) was 55% higher compared to outdoor culture (μ = 0.0163 h−1), but biomass production was 1.3 times higher in outdoor culture (Outdoor = 91.7 mg m−2d−1; Photobioreactor = 69 mg m−2d−1). Outdoor culture produced 18% higher lipid; while total fatty acids (FA) was not significantly affected by the change in
culture systems as both cultures yield almost similar concentrations of fatty acids per gram of sample (photobioreactor = 119.17 mg
g−1; outdoor culture = 104.50 mg g−1); however, outdoor cultured Isochrysis sp. had 26% more polyunsaturated fatty acids (PUFAs). Rotifers cultured in Isochrysis sp./ Nanochloropsis sp. (1:1, v/v) mixture gave similar growth rate as 100% Nanochoropsis sp. culture (μ = 0.40 d−1), but had 45% higher counts of rotifers with eggs (t = 7, maximum). The Isochrysis sp. culture successfully lowered the nitrate (46%) and orthophosphate (83%) during outdoor culture. 相似文献
17.
Jeroen Speybroeck Joke Van Tomme Magda Vincx Steven Degraer 《Helgoland Marine Research》2008,62(3):257-268
Population dynamics and zonation of the amphipods Bathyporeia pilosa and B.
sarsi, co-occurring on some beaches, were studied through monthly sampling of eight cross-shore transects along the Belgian coast
(October 2003–October 2004). Their biomass and production were assessed for the first time. Abundance and biomass of B. pilosa were ten times higher along western ultra-dissipative transects than along slightly more reflective, eastern transects. For
B. sarsi (less prominent), differences between the two westernmost transects (2–5× higher) and all others were observed, whereas P/B
ratio was comparable for all. B. pilosa could reach two times higher abundance and biomass and higher levels of production (max B. sarsi = 7,580 g m−2 y−1; max B. pilosa = 16,040 g m−2 y−1), while the species was nearly absent from the eastern transects. Continuous reproduction and recruitment with three relative
peaks of the latter (February, July, October) were observed. Fecundity showed parallel temporal variation for both species,
peaking in February and September–October. Interestingly, the July relative “recruitment” peak could not be explained by relative
abundance of gravid females or fecundity, but was probably caused by adult mortality. Both species displayed comparable gonad
production (B. pilosa: P
g
= 0.73 mg/ind year; B. sarsi:
P
g
= 0.71 mg/ind year), but B. pilosa produced fewer yet larger embryos. Peak abundances were found at 436 ± 25 SD cm (B. pilosa) and 357 ± 40 SD cm (B. sarsi) above MLLWS, corresponding to a 40–62 m cross-shore distance between the peaks of both species. The occupied cross-shore
range was larger for B. sarsi than for B. pilosa (35–54 m), for females than for males (15–23 m), and for adults than for juveniles of B. pilosa (5–8 m). Both species displayed many comparable life history features. Differences in abundance and biomass may be related
to beach morphodynamics and zonation. 相似文献
18.
Yantree Devi Sankar-Thomas Katja Saare-Surminski Reinhard Lieberei 《Plant Cell, Tissue and Organ Culture》2008,95(2):163-173
The present study describes a protocol for plant regeneration via somatic embryogenesis in temporary immersion system (TIS)
for Camptotheca acuminata. Somatic embryos were induced by culturing hypocotyl segments from 14-day-old in vitro grown C. acuminata seedlings in TIS. Hypocotyl segments were placed in culture vessels modified with a mechanical device to support the fixation
of explants. Cultures were maintained under a 16 h photoperiod with a light intensity of 60 μmol m−2 s−1 PPF at 25 ± 1°C. After 16 weeks of incubation embryogenic calli were formed above the edge of the mechanical device in the
basal Murashige and Skoog (MS) medium containing 35 g l−1 sucrose and without hormonal supplementation. For plantlet regeneration, somatic embryos at cotyledonary stage were cultured
in three different concentrations of 6-benzylamino-purine (0.5, 1.0 and 1.5 mg l−1 BAP) and in plant growth regulator (PGR) free medium. In general, 0.5 mg l−1 BAP was found to be the most effective concentration for growth and development of Camptotheca embryos in TIS. Conversion of somatic embryos into plantlets was also successfully achieved on sterile substrates moistened
with 0.5 mg l−1 BAP. Plantlets derived from cotyledonary embryos were rooted in vitro with 0.5 mg l−1 indole-3-butyric acid (IBA) before transfer to ex vitro conditions. 相似文献
19.
Abdeljabbar Hedi Marie-Laure Fardeau Najla Sadfi Abdellatif Boudabous Bernard Ollivier Jean-Luc Cayol 《Extremophiles : life under extreme conditions》2009,13(2):313-319
A new halophilic anaerobe was isolated from the hypersaline surface sediments of El-Djerid Chott, Tunisia. The isolate, designated
as strain 6SANG, grew at NaCl concentrations ranging from 14 to 30%, with an optimum at 20–22%. Strain 6SANG was a non-spore-forming,
non-motile, rod-shaped bacterium, appearing singly, in pairs, or occasionally as long chains (0.7–1 × 4–13 μm) and showed
a Gram-negative-like cell wall pattern. It grew optimally at pH values between 7.2 and 7.4, but had a very broad pH range
for growth (5.9–8.4). Optimum temperature for growth was 42°C (range 30–50°C). Strain 6SANG required yeast extract for growth
on sugars. Glucose, sucrose, galactose, mannose, maltose, cellobiose, pyruvate, and starch were fermented. The end products
from glucose fermentation were acetate, butyrate, lactate, H2, and CO2. The G + C ratio of the DNA was 34.3 mol%. Strain 6SANG exhibited 16S rRNA gene sequence similarity values of 91–92% with
members of the genus Halobacteroides, H. halobius being its closest phylogenetic relative. Based on phenotypic and phylogenetic characteristics, we propose that this bacterium
be classified as a novel species of a novel genus, Halanaerobaculum tunisiense gen. nov., sp. nov. The type strain is 6SANGT (=DSM 19997T = JCM 15060T). 相似文献
20.
Highly efficient Agrobacterium-based transformation system for callus cells of the C3 halophyte Suaeda salsa 总被引:1,自引:0,他引:1
Genetic manipulation technologies have been limited in the halophyte Suaeda salsa L. due to the lack of an efficient transformation system. Here, we examined factors affecting transformation and developed
an efficient transformation system at the cell level using S. salsa hypocotyl as starting material. S. salsa hypocotyl explants from 10-day-old seedlings were precultured for 2 days on a hygromycin (hyg)-free callus induction medium
(CIM) and then inoculated with Agrobacterium tumefaciens suspension at a concentration of 0.5 at OD600 for 5–10 min. After cocultivation with A. tumefaciens for 4 days in the dark, followed by selection on carbenicillin (carb) for 3 days, explants were placed on CIM containing
10 mg l−1 hyg and 500 mg l−1 carb with three to four consecutive subcultures for up to 45 days. β-Glucuronidase assays showed an average transformation
frequency of 62.89%. Gene integration was confirmed by polymerase chain reaction analysis and Northern blot analysis. To our
knowledge, this is the first study to show Agrobacterium-mediated transformation in the C3 halophyte S. salsa. 相似文献