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1.
OVAT (one variable at a time) approach was applied in this study to screen the most important physicochemical key determinants
involved in the process of sheep wool biodegradation. The process was directed by a keratinase-producing Bacillus subtilis DB 100 (p5.2) recombinant strain. Data indicate that, sheep wool could be degraded efficiently in cultures incubated at 30°C,
with initial pH of 7 with agitation at 150 rpm. Two times autoclaved alkali treated and undefatted chopped sheep wool is more
accessible to biodegradation. B. subtilis recombinant cells could utilize sheep wool as a sole source of carbon and nitrogen. Sheep wool-based modified basal medium
II, lacking NH4Cl and yeast extract, could greatly support the growth of these bacterial cells. Sheep wool biodegradation was conducted efficiently
in the absence of kanamycin consequently; high stability of the recombinant plasmid (p5.2) represents a great challenge upon
scaling up this process. Three key determinants (sheep wool concentration, incubation time and inoculum size) imposing considerable
constraints on the process are highlighted. Sheep wool-based tap water medium and sheep wool-based distilled water medium
were formulated in this study. High levels of released end products, produced from sheep wool biodegradation are achieved
upon using these two sheep wool-based water media. Data indicate that, sheep wool hydrolysate is rich in some amino acids,
such as tyrosine, phenylalanine, lysine, proline, isoleucine, leucine, valine, aspartic acid and glutamic acid. Moreover,
the resulting sheep wool hydrolysate contains soluble proteins of high and intermediate molecular weights. The present study
demonstrates a feasible, cheap, reproducible, efficient and rapid biotechnological approach towards utilization of raw sheep
wool waste through a recombinant bacterium. 相似文献
2.
Biodegradation of chicken feathers waste directed by Bacillus subtilis recombinant cells: scaling up in a laboratory scale fermentor 总被引:3,自引:0,他引:3
Biodegradation of chicken feathers waste directed by Bacillus subtilis DB 100 (p5.2) cells was successfully carried out in 14 L Bio Flo 110 laboratory scale fermentor. Seven liters of feathers-based modified basal medium II, feathers-based tap water and feathers-based distilled water separately in the fermentor were inoculated with activated bacterial cells. The fermentation processes were conducted at 37 °C, 700 rpm agitation speed and 0.7 vvm air flow rate in the absence of kanamycin. Highest net levels of released feathers hydrolysis end products [soluble proteins and NH2-free amino groups] and keratinolytic alkaline protease activity in the fermentor were greatly comparable to those of shake flasks. Interestingly, the plasmid (p5.2) inside the recombinant B. subtilis cells growing in the fermentor displayed 100% stability till the fifth day of incubation and this presents a great challenge. Data certainly would encourage the transfer to larger scale fermentors to carry out feathers biodegradation process. 相似文献
3.
Solid-state fermentation conditions for cellulases production by a newly isolated Penicillium chrysogenum QML-2 were investigated using statistical methods. At first, significant variables for cellulases production including (NH4)2SO4, initial pH and inoculum size were screened by using Plackett-Burman Design. Then the optimal regions of the significant
variables were investigated by using the method of steepest ascent. Finally, central composite design and response surface
analysis were adopted to determine the optimal values of the significant variables and investigate the combined effects of
each variable’s pair on cellulases production. The results showed that the optimal ranges of (NH4)2SO4 concentration, initial pH and inoculum size for three types of cellulases activities were 1.97–2.15 g, pH 4.32–4.41 and 13.3–13.7%
(v/w), respectively. Using the mixture of corn stover powder and wheat bran (CSP/WB, 1/1) as carbon source, the optimization
resulted in 370.15, 101.76 and 321.56 U/g for maximal endoglucanase activity, filter paper activity and β-glucosidase activity,
respectively. Compared with maximum values of cellulases activities (endoglucanase activity 85.21 U/g, filter paper activity
16.62 U/g and β-glucosidase activity 67.68 U/g) obtained under unoptimized conditions, the optimization resulted in 3.34,
5.12 and 3.75 folds improvement for endoglucanase activity, filter paper activity and β-glucosidase activity, respectively.
For chitosan hydrolysis, the crude cellulases had the optimal temperature of 55°C, pH of 4.4 and exhibited Michaelis constant
(K
m) value of 8.34 mg/ml and maximum velocity (V
max) of 2.21 μmol glucosamine/min by 1 ml of the crude cellulases. 相似文献
4.
Jin-Ha Jeong Young-Dong Jeon O-Mi Lee Jeong-Do Kim Na-Ri Lee Geun-Tae Park Hong-Joo Son 《Biodegradation》2010,21(6):1029-1040
In this study, we isolated and characterized a novel feather-degrading bacterium that shows keratinolytic, antifungal and
plant growth-promoting activities. A bacterium S8 was isolated from forest soil and confirmed to belong to Bacillus subtilis by BIOLOG system and 16S rRNA gene analysis. The improved culture conditions for the production of keratinolytic protease
were 0.1% (w/v) sorbitol, 0.3% (w/v) KNO3, 0.1% (w/v) K2HPO4, 0.06% (w/v) KH2PO4 and 0.04% (w/v) MgCl2·6H2O (pH 8.0 and 30°C), respectively. In the improved medium containing 0.1% (w/v) feather, keratinolytic protease production
was around 53.3 ± 0.3 U/ml at 4 day; this value was 10-fold higher than the yield in the basal feather medium (5.3 ± 0.1 U/ml).
After cultivation for 5 days in the improved medium, intact feather was completely degraded. Feather degradation resulted
in free –SH group, soluble protein and amino acids production. The concentration of free –SH group in the culture medium was
15.5 ± 0.2 μM at 4 days. Nineteen amino acids including all essential amino acids were produced in the culture medium; the
concentration of total amino acid produced was 3360.4 μM. Proline (2809.9 μM), histidine (371.3 μM) and phenylalanine (172.0 μM)
were the major amino acids released in the culture medium. B. subtilis S8 showed the properties related to plant growth promotion: hydrolytic enzymes, ammonification, indoleacetic acid (IAA),
phosphate solubilization, and broad-spectrum antimicrobial activity. Interestingly, the strain S8 grown in the improved medium
produced IAA and antifungal activity, indicating simultaneous production of keratinolytic and antifungal activities and IAA
by B. subtilis S8. These results suggest that B. subtilis S8 could be not only used to improve the nutritional value of feather wastes but also is useful in situ biodegradation of
feather wastes. Furthermore, it could also be a potential biofertilizer or biocontrol agent applicable to crop plant soil. 相似文献
5.
Lenka Vojtíšková Edita Munzarová Olga Votrubová Hana Čížková Helena Lipavská 《Hydrobiologia》2006,563(1):73-85
Carbon and nitrogen balance in Acorus calamus, a wetland species colonising littoral zones with a high trophic status, was studied under experimental conditions using
water or sand culture with a defined composition of the nutrient solution. Influence of graded level of N (1.86, 7.5 and 18.6
mM) and/or forms of N (NH4+ versus NO 3–) on the content of non-structural carbohydrates, free amino acids, total C, and total N was studied in Acorus rhizomes and roots to find possible connection with a reduced growth of Acorus plants under high N and NH4+–N nutrition described in our previous study [Vojtíšková et al., 2004. Hydrobiologia 518: 9–22]. High N availability and pure
NH4+–N nutrition affected the C/N balance of rhizome and root systems of Acorus in a similar way. NH4+–N was the only form of N elevated under the high N treatment. The major proportion of the total non-structural carbohydrates
(TNC) was starch (91–93% and 51–64% in rhizomes and roots, respectively). The content of starch was significantly and and
negatively affected by high N availability (P = 0.001), as well as by NH4+–N nutrition (P=0.001). Amounts of simple soluble carbohydrates (sucrose, glucose, and fructose) were negligible in comparison to starch
in rhizomes and branched roots (up to 5% of TNC), while roots without developed lateral roots (unbranched) contained up to
33% of TNC in the form of simple soluble sugars. Moreover, high hexoses/sucrose ratio, low starch/soluble sugars ratio, high
content of N, and low C/N ratio support the notion that unbranched roots are metabolically active young roots with tissue
differentiation in progress. A high content of free amino acids, typically with dominance of N-rich amino acids (Arg-46%,
Gln-8%, Asn-7%), was found simultaneously with a low carbohydrate content under high N supply, which indicates that NH4+ received is effectively incorporated into the organic form by this species. Since the decrease in carbohydrate content was
not accompanied by luxurious growth, other possible carbon consuming processes were discussed in relation to NH4+ nutrition. More dramatic changes in total N than C were found under high N availability resulting a shift in C/N ratio in
favour of N. Although the shift towards N metabolism was obvious, no serious carbohydrate depletion occurred, which could
explain the reduced growth of Acorus plants under high N and sole NH4+–N nutrition described previously. 相似文献
6.
Inhibition of ribonuclease and protease activities in germinating rice seeds exposed to nickel 总被引:1,自引:0,他引:1
When the seeds of two rice cvs. Malviya-36 and Pant-12 were germinated up to 120 h in the presence of 200 and 400 μM NiSO4, a significant reduction in the germination of seeds occurred. Seeds germinating in the presence of 400 μM NiSO4 showed about 12–20% decline in germination percent, about 20–53% decline in lengths and about 8–34% decline in fresh weights
of roots and shoots at 120 h of germination. Ni2+ exposure of germinating seeds resulted in apparent increased levels of RNA, soluble proteins, and free amino acids in endosperms
as well as embryo axes. A 400 μM Ni2+ treatment led to about 58–101% increase in the level of soluble proteins and about 39–107% increase in the level of free
amino acids in embryo axes at 96 h of germination. Activities of ribonuclease and protease declined significantly with increasing
levels of Ni2+ treatment. Isoenzyme profile of RNase as revealed by activity staining indicated decline in the intensities of 3–4 preexisting
enzyme isoforms in embryo axes of both the rice cultivars and disappearance of one of the two isoforms in endosperms of cv. Pant-12 due to 400 μM Ni2+ treatment. Results suggest that the presence of high level of Ni2+ in the medium of germinating rice seeds serves as a stress factor resulting in decreased hydrolysis as well as delayed mobilization
of endospermic RNA and protein reserves and causing imbalance in the level of biomolecules like RNA, proteins, and amino acids
in growing embryo axes. These events would ultimately contribute to decreased germination of rice seeds in high Ni2+ containing environment. 相似文献
7.
Y. Sudheer Kumar S. Varakumar O. V. S. Reddy 《World journal of microbiology & biotechnology》2010,26(11):1973-1980
Mango peel is one of the major wastes from fruit processing industries, which poses considerable disposal problems and ultimately
leads to environmental pollution. The objective of the current research was to determine the significant parameters on the
production of polygalacturonase from mango peel which is a major industrial waste. Solid state culture conditions for polygalacturonase
production by Fusarium moniliforme from dried mango peel powder were optimized by Taguchi’s L-18 orthogonal array experimental design methodology. Eight fungal
metabolic influencing variables, viz. temperature, mango peel, inoculum, peptone, ammonium nitrate (NH4NO3), magnesium sulphate (MgSO4), zinc sulphate (ZnSO4) and potassium dihydrogen phosphate (KH2PO4) were selected to optimize polygalacturonase production. The optimized parameters composed of temperature (30°C), mango peel
(6.5%, g, w/v), inoculum (8%, ml, v/v), peptone (1%, g, w/v), NH4NO3 (0.60%, g, w/v), MgSO4 (0.05%, g, w/v), ZnSO4 (0.06%, g, w/v) and KH2PO4 (0.4%, g, w/v). Based on the influence of interaction of fermentation components of fermentation, these could be classified
as the least significant and the most significant at individual and interaction levels. The temperature, inoculum level, mango
peel substrate and KH2PO4 showed maximum production impact at optimized conditions. From the optimized conditions the polygalacturonase activity was
maximized to 43.2 U g−1. 相似文献
8.
The treatment performance of an upflow microaerobic sludge blanket reactor (UMSB) for synthetic domestic wastewater was investigated
at two dissolved oxygen (DO) levels, 0.3–0.5 and 0.7–0.9 mg l−1, focusing on nitrification performance. The higher DO level induced complete nitrification of ammonia nitrogen (NH3–N), achieving chemical oxygen demand and NH3–N removals of 97 and 92%, respectively. There were consistently significantly higher nitrate nitrogen (NO3–N) and nitrite nitrogen (NO2–N) levels in the effluent, with ~66% of newly-produced oxidised nitrogen as NO2–N. Despite the high nitrification efficiency, only about 23% of the removed NH3–N amount from the influent was ultimately transformed into oxidised nitrogen due to the simultaneous nitrification-denitrification.
Sludge blanket development and granulation occurred simultaneously in the UMSB. 相似文献
9.
《Process Biochemistry》2007,42(4):518-526
An alkaline lipase from Burkholderia multivorans was produced within 15 h of growth in a 14 L bioreactor. An overall 12-fold enhanced production (58 U mL−1 and 36 U mg−1 protein) was achieved after medium optimization following the “one-variable-at-a-time” and the statistical approaches. The optimal composition of the lipase production medium was determined to be (% w/v or v/v): KH2PO4 0.1; K2HPO4 0.3; NH4Cl 0.5; MgSO4·7H2O 0.01; yeast extract 0.36; glucose 0.1; olive oil 3.0; CaCl2 0.4 mM; pH 7.0; inoculum density 3% (v/v) and incubation time 36 h in shake flasks. Lipase production was maximally influenced by olive oil/oleic acid as the inducer and yeast extract as the additive nitrogen. Plackett–Burman screening suggested catabolite repression by glucose. Amongst the divalent cations, Ca2+ was a positive signal while Mg2+ was a negative signal for lipase production. RSM predicted that incubation time, inoculum density and oil were required at their higher levels (36 h, 3% (v/v) and 3% (v/v), respectively) while glucose and yeast extract were required at their minimal levels for maximum lipase production in shake flasks. The production conditions were validated in a 14 L bioreactor where the incubation time was reduced to 15 h. 相似文献
10.
Rodney J. Fuller John G. Carman J. Richard Hess 《Plant Cell, Tissue and Organ Culture》2009,99(2):183-192
In vitro zygotic and somatic embryogenesis protocols rely on nutrient and hormone levels from media to satisfy the physiological
and developmental requirements of embryony. To better understand these requirements for cotton, we quantified levels of major
and minor elements, carbohydrates, NH4
+, free amino acids and six hormones in whole cotton ovules (with fibers removed), nucelli (ovules with integuments removed),
or ovule fluid (extracted from the endosperm region). Samples were collected from field-grown cotton at 1–18 days-past-anthesis
(DPA) during each of three growing seasons. Replication across 2 years was obtained for carbohydrates, NH4
+, free amino acids and hormones from nucellus samples. The year effect was large primarily for hormones only. The most abundant
minerals across tissue types and years were K, P, Mg and S. Potassium was the most abundant at 260, 600 and 1,660 mmol kg−1 dry mass (DM) in nucelli, whole ovules and ovule fluid, respectively. Magnesium, Ca, Zn and Mn levels were 2–8-fold higher
in ovule fluid compared to whole ovules or nucelli. In the free amino acid plus NH4
+ category, NH4
+, alanine, serine, glycine, asparagine (plus aspartic acid), glutamine (plus glutamic acid), leucine, threonine and arginine
predominated in nucelli and ovule fluid, and levels tended to be higher in the older samples across years and tissue types.
Fructose and glucose levels also increased with age with very high levels being found in late DPA ovule fluid. Arabinose,
inositol and melibiose were also prominent sugars. Indole-3-acetic acid levels were similar between nucelli and ovule fluid
and ranged from 10 to 80 μmol kg−1 DM. An abscisic acid spike, from 15 to 400 μmol kg−1 DM, occurred in nucelli and whole ovules from 2 to 8 DPA. Thereafter, abscisic acid levels remained between 5 and 10 μmol kg−1 DM. Zeatin and zeatin riboside were the most abundant cytokinins, and levels of these hormones fluctuated between 1 and 4 μmol kg−1 DM in both nucelli and ovule fluid. 相似文献
11.
Yi-Guang Chen Shu-Kun Tang Yu-Qin Zhang Zhu-Xiang Liu Qi-Hui Chen Jian-Wu He Xiao-Long Cui Wen-Jun Li 《Extremophiles : life under extreme conditions》2010,14(4):397-402
A novel moderately halophilic, alkaliphilic, non-motile, non-sporulating, catalase-positive, oxidase-negative, aerobic, coccus-shaped,
Gram-positive bacterium, designated strain JSM 071043T, was isolated from a subterranean brine sample collected from a salt mine in Hunan Province, China. Growth occurred with
0.5–20% (w/v) NaCl (optimum 5–10%) at pH 6.5–10.5 (optimum pH 8.5) and at 10–40°C (optimum 25–30°C). Good growth also occurred
in the presence of 0.5–20% (w/v) KCl (optimum 5–8%) or 0.5–25% (w/v) MgCl2·6H2O (optimum 5–10%). The peptidoglycan type was A4α (l-Lys–l-Ala–l-Glu) and major cell-wall sugars were tyvelose and mannose. The major cellular fatty acids were anteiso-C15:0, iso-C16:0 and anteiso-C17:0. Strain JSM 071043T contained MK-9 and MK-8 as the predominant menaquinones and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol
as the major polar lipids. The DNA G + C content was 67.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed
that strain JSM 071043T was a member of the suborder Micrococcineae, and was most closely related to Zhihengliuella halotolerans YIM 70185T (sequence similarity 98.9%) and Zhihengliuella alba YIM 90734T (98.2%), and the three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis,
DNA–DNA relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 071043T represents a novel species of the genus Zhihengliuella, for which the name Z. salsuginis sp. nov. is proposed. The type strain is JSM 071043T (= DSM 21149T = KCTC 19466T). 相似文献
12.
MA Giraldo TM da Silva F Salvato HF Terenzi JA Jorge LH Guimarães 《World journal of microbiology & biotechnology》2012,28(2):463-472
The filamentous fungus Paecylomices variotii was able to produce high levels of cell extract and extracellular invertases when grown under submerged fermentation (SbmF)
and solid-state fermentation, using agroindustrial products or residues as substrates, mainly soy bran and wheat bran, at
40°C for 72 h and 96 h, respectively. Addition of glucose or fructose (≥1%; w/v) in SbmF inhibited enzyme production, while
the addition of 1% (w/v) peptone as organic nitrogen source enhanced the production by 3.7-fold. However, 1% (w/v) (NH4)2HPO4 inhibited enzyme production around 80%. The extracellular form was purified until electrophoretic homogeneity (10.5-fold
with 33% recovery) by DEAE-Fractogel and Sephacryl S-200 chromatography. The enzyme is a monomer with molecular mass of 102 kDa
estimated by SDS–PAGE with carbohydrate content of 53.6%. Optima of temperature and pH for both, extracellular and cell extract
invertases, were 60°C and 4.0–4.5, respectively. Both invertases were stable for 1 h at 60°C with half-lives of 10 min at
70°C. Mg2+, Ba2+ and Mn2+ activated both extracellular and cell extract invertases from P. variotii. The kinetic parameters Km and Vmax for the purified extracellular enzyme corresponded to 2.5 mM and 481 U/mg prot−1, respectively. 相似文献
13.
Anu Vikman Sakari Sarkkola Harri Koivusalo Tapani Sallantaus Jukka Laine Niko Silvan Hannu Nousiainen Mika Nieminen 《Hydrobiologia》2010,641(1):171-183
We studied the nitrogen retention capacity of six peatland buffer areas constructed in forested catchments in southern and
central Finland. The buffers (0.1–4.9% of the total catchment area) were either undrained mires or drained peatlands rewetted
4–7 years before the present study. The N retention capacity was studied by adding ammonium nitrate (NH4NO3–N) solution into the inflow waters of the buffers once (one area) or twice (five areas) during a period of 4–6 years. Except
for the first N addition in one area, the three largest buffer areas (relative size > 1%) retained the added inorganic N almost
completely; their retention efficiencies during the year of addition were >93% for both NO3–N and NH4–N. Two of the three small buffers (relative size < 0.25%) were also able to reduce inorganic N from the through-flow waters
effectively; their retention capacities for inorganic nitrogen varied between 58 and 89%. However, one small buffer area had
a retention capacity of only <20%. The factors contributing to efficient N retention were hydrological load during N addition,
relative size of the buffer area, and its length, i.e. the distance between the inflow and outflow points. If there was any
release of the added N, it mostly occurred within a relatively short-time period (<100 days) after the treatment. The buffer
areas appeared to be efficient and long-term sinks for inorganic nitrogen because the release of N during the 2–4 years after
N addition was minor. 相似文献
14.
Responses to excessive ammonium (NH4
+) were compared between two Arabidopsis ecotypes (Col-0, JA22) with respect to different photoperiods in hydroponics. In this study, we showed that external extra
NH4
+ led to severe growth suppression, accumulations of free NH4
+ and amino acids and increased the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in shoots of
the two Arabidopsis ecotypes. However, the levels of free NH4
+ and total amino acids increased, whereas the activities of GS, NADH-dependent glutamate synthase and GDH decreased under
the continuous light when compared with the light (16 h)–dark (8 h) cycle photoperiod. Statistical analyses suggested that
strong correlations exist among the growth reduction, accumulations of free NH4
+, total amino acids and levels of GS activity in shoots under the high NH4
+ stress regardless of the photoperiod regimes. Interestingly, under the continuous light, Col-0 showed more resistant to such
growth reduction and maintained about onefold higher capability of converting excess free NH4
+ into amino acids, with onefold higher GS activity induced by the external NH4
+ when compared with JA22. In contrast, these differences were abolished between Col-0 and JA22 under the light–dark cycle
condition. Taken together, our results conclude that the sensitivity to NH4
+ of Col-0 and JA22 is changed between the continuous light and the light–dark cycle photoperiod, which is correlative to the
alteration of the GS activity in shoots. 相似文献
15.
Nitrifying granules cultivation in a sequencing batch reactor at a low organics-to-total nitrogen ratio in wastewater 总被引:4,自引:0,他引:4
It is possible to cultivate aerobic granular sludge at a low organic loading rate and organics-to-total nitrogen (COD/N) ratio
in wastewater in the reactor with typical geometry (height/diameter = 2.1, superficial air velocity = 6 mm/s). The noted nitrification
efficiency was very high (99%). At the highest applied ammonia load (0.3 ± 0.002 mg NH4+–N g total suspended solids (TSS)−1 day−1, COD/N = 1), the dominating oxidized form of nitrogen was nitrite. Despite a constant aeration in the reactor, denitrification
occurred in the structure of granules. Applied molecular techniques allowed the changes in the ammonia-oxidizing bacteria
(AOB) community in granular sludge to be tracked. The major factor influencing AOB number and species composition was ammonia
load. At the ammonia load of 0.3 ± 0.002 mg NH4+–N g TSS−1 day−1, a highly diverse AOB community covering bacteria belonging to both the Nitrosospira and Nitrosomonas genera accounted for ca. 40% of the total bacteria in the biomass. 相似文献
16.
A stirred vessel coupled with membrane unit containing cellulose acetate (0.45 μm) membrane was used to study the decolorization
of anaerobically digested molasses spent wash (MSW). The soil collected from the MSW disposal site was used as inoculum to
study the decolorization without addition of any additives. The same inoculum was used over a period of 163 days at room temperature
to study the decolorization of 12.5–50% (v/v) MSW using different operational conditions. The reactor was entered in to the
inhibition mode after the feeding of 50% MSW, which was restored 100% without changing any operational condition. The maximum
decolorization obtained for 12.5% (v/v) MSW was 77.22 ± 0.13%. The decolorization achieved for 25, 37.5, and 50% (v/v) MSW
was 70.41 ± 0.12, 56.47 ± 0.17, and 48.78 ± 0.09%, respectively. Increase in the utilization of protein and reducing sugar
was observed up to 25% MSW whereas, higher concentration showed decrease in the utilization. Results indicate 63% removal
of chemical oxygen demand for 12.5% (v/v) MSW. Membrane flux which was significantly reduced after the feeding of 50% MSW
was regenerated without changing the washing procedure, however, 35% decrease in sample flux was observed over the continuous
use of membrane for the period of 198 days. 相似文献
17.
Pawel Listwan Thomas C. Terwilliger Geoffrey S. Waldo 《Journal of structural and functional genomics》2009,10(1):47-55
Overproduction of soluble and stable proteins for functional and structural studies is a major bottleneck for structural genomics
programs and traditional biochemistry laboratories. Many high-payoff proteins that are important in various biological processes
are “difficult to handle” as protein reagents in their native form. We have recently made several advances in enabling biochemical
technologies for improving protein stability (), allowing stratagems for efficient protein domain trapping, solubility-improving mutations, and finding protein folding
partners. In particular split-GFP protein tags are a very powerful tool for detection of stable protein domains. Soluble,
stable proteins tagged with the 15 amino acid GFP fragment (amino acids 216–228) can be detected in vivo and in vitro using
the engineered GFP 1–10 “detector” fragment (amino acids 1–215). If the small tag is accessible, the detector fragment spontaneously
binds resulting in fluorescence. Here, we describe our current and on-going efforts to move this process from the bench (manual
sample manipulation) to an automated, high-throughput, liquid-handling platform. We discuss optimization and validation of
bacterial culture growth, lysis protocols, protein extraction, and assays of soluble and insoluble protein in multiple 96
well plate format. The optimized liquid-handling protocol can be used for rapid determination of the optimal, compact domains
from single ORFS, collections of ORFS, or cDNA libraries. 相似文献
18.
Leaf-chewing herbivores select food with a protein/carbohydrate ratio of 0.8–1.5, whereas phloem sap, which aphids feed on,
has a ratio of ~0.1. Enhanced N fertilization increases the amino acid concentration in phloem sap and elevates the N/C ratio.
The study examines: (1) whether aphids select between plants of different N nutrition, (2) whether feeding time correlates
with the amino acid composition of phloem sap, and (3) at which stage of probing aphids identify the quality of the plant.
Uroleucon tanaceti (Mordvilko) and Macrosiphoniella tanacetaria (Kaltenbach), specialist aphids feeding on tansy (Tanacetum vulgare L.), were reared on this host plant grown essentially hydroponically (in Vermiculite) in the greenhouse on 1, 3, 6, or 12 mM
NH4NO3. One and 3 mM NH4NO3 corresponds to the situation found in natural tansy stands. Aphid stylet penetration was monitored by electrical penetration
graphs whilst phloem sap was sampled by stylectomy. Both aphid species settled 2–3 times more frequently on plants fertilized
with 6 or 12 mM NH4NO3. The phloem sap of these plants contained up to threefold higher amino acid concentrations, without a change in the proportion
of essential amino acids. No time differences were observed before stylet penetration of plant tissue. After the first symplast
contact, most aphids penetrated further, except M. tanacetaria on low-N plants, where 50% withdrew the stylet after the first probing. The duration of phloem feeding was 2–3 times longer
in N-rich plants and the time spent in individual sieve tubes was up to tenfold longer. Aphids identified the nutritional
quality of the host plant mainly by the amino acid concentration of phloem sap, not by leaf surface cues nor the proportion
of essential amino acids. However, U. tanaceti infestation increased the percentage of methionine plus tryptophan in phloem tenfold, thus manipulating the plants nutritional
quality, and causing premature leaf senescence. 相似文献
19.
Yi-Guang Chen Jun Chen Qi-Hui Chen Shu-Kun Tang Yu-Qin Zhang Jian-Wu He Wen-Jun Li Yan-Qi Liu 《Antonie van Leeuwenhoek》2010,98(3):395-401
A novel Gram-stain-positive, slightly halophilic, facultatively alkaliphilic, non-motile, non-sporulating, catalase-positive,
oxidase-negative, aerobic bacterium, designated strain JSM 070026T, was isolated from non-saline forest soil in China. Growth occurred with 0–20% (w/v) NaCl (optimum, 2–4%) and at pH 6.0–10.5
(optimum, pH 8.0) and 5–40°C (optimum, 30°C). Good growth also occurred in the presence of 0–28% (w/v) KCl (optimum, 2–5%)
or 0–25% (w/v) MgCl2·6H2O (optimum, 1–4%). The peptidoglycan type was A4α (l-Lys–Gly–l-Glu). Cell-wall sugars contained mannose and xylose. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. Strain
JSM 070026T contained menaquinone 8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol
as the major polar lipids. The DNA G + C content of strain JSM 070026T was 56.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JSM 070026T was a member of the suborder Micrococcineae and most closely related to Yaniella flava YIM 70178T (sequence similarity 99.4%) and Yaniella halotolerans YIM 70085T (97.9%). The three strains formed a distinct branch in the phylogenetic tree. The combination of phylogenetic analysis, DNA–DNA
relatedness values, phenotypic characteristics and chemotaxonomic data supports the proposal that strain JSM 070026T represents a novel species of the genus Yaniella, for which the name Yaniella soli sp. nov. is proposed. The type strain is JSM 070026T (=DSM 22211T = KCTC 13527T). 相似文献
20.
Four different bacterial strains were isolated from pulp and paper mill sludge in which one alkalotolerant isolate (LP1) having
higher capability to remove color and lignin, was identified as Bacillus sp. by 16S RNA sequencing. Optimization of process parameters for decolorization was initially performed to select growth
factors which were further substantiated by Taguchi approach in which seven factors, % carbon, % black liquor, duration, pH,
temperature, stirring and inoculum size, at two levels, applying L-8 orthogonal array were taken. Maximum color was removed
at pH 8, temperature 35°C, stirring 200 rpm, sucrose (2.5%), 48 h, 5% (w/v) inoculum size and 10% black liquor. After optimization
2-fold increase in color and lignin removal from 25–69% and 28–53%, respectively, indicated significance of Taguchi approach
in decolorization and delignification of lignin in pulp and paper mill effluent. Enzymes involved in the process of decolorization
of effluent were found to be xylanase (54 U/ml) and manganese peroxidase (28 U/ml). Treated effluent was also evaluated for
toxicity by Comet assay using Saccharomyces cerevisiae MTCC 36 as model organism, which indicated 58% reduction after treatment by bacterium. 相似文献