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1.
The purpose of this research was to investigate the influence of changes in the amorphous state on the crystallization of
trehalose. Amorphous trehalose is known to stabilize biomaterials; hence, an understanding of crystallization is vital. Amorphous
trehalose, prepared by spray-drying, was exposed to either a single step (0–75%) in relative humidity (RH) or to modulated
0–75–0% RH to cause crystallization. For the single-step experiment, two samples crystallized in a predictable manner to form
the dihydrate. One sample, while notionally identical, did not crystallize in the same way and showed a mass loss throughout
the time at 75% RH, with a final mass less than that expected for the dihydrate. The idiosyncratic sample was seen to have
a starting near infrared (NIR) spectra similar to that exhibited by anhydrous crystalline trehalose, implying that short-range
order in the amorphous material (or a small amount of crystalline seed, not detectable using powder X-ray diffraction) caused
the sample to fail to form the dihydrate fully when exposed to high RH. The modulated RH study showed that the amorphous material
interacted strongly with water; the intensity of the NIR traces was not proportional to mass of water but rather the extent
of hydrogen bonding. Subsequent crystallization of this sample clearly was a partial formation of the dihydrate, but with
the bulk of the sample then shielded such that it was unable to show significant sorption when exposed to elevated RH. It
has been shown that the nature of the amorphous form will alter the way in which samples crystallize. With oscillation in
RH, it was possible to further understand the interactions between water and amorphous trehalose. 相似文献
2.
Susanne G. L. Quaak John B. A. G. Haanen Jos H. Beijnen Bastiaan Nuijen 《AAPS PharmSciTech》2010,11(1):344-350
Since plasmid DNA (pDNA) is unstable in solution, lyophilisation can be used to increase product shelf life. To prevent stress
on pDNA molecules during lyophilisation, cryo- and lyoprotectants have to be added to the formulation. This study assessed
the effect of disaccharides on naked pDNA stability after lyophilisation using accelerated stability studies. Naked pDNA was
lyophilised with sucrose, trehalose, maltose or lactose in an excipient/DNA w/w ratio of 20. To one part of the vials extra residual moisture was introduced by placing the vials half opened in a 25°C/60%
RH climate chamber, before placing all vials in climate chambers (25°C/60% RH and 40°C/75% RH) for stability studies. An ex vivo human skin model was used to assess the effect of disaccharides on transfection efficiency. Lyophilisation resulted in amorphous
cakes for all disaccharides with a residual water content of 0.8% w/w. Storage at 40°C/75% RH resulted in decreasing supercoiled (SC) purity levels (sucrose and trehalose maintained approximately
80% SC purity), but not in physical collapse. The addition of residual moisture (values between 7.5% and 10% w/w) resulted in rapid collapse except for trehalose and decreasing SC purity for all formulations. In a separate experiment
disaccharide formulation solutions show a slight but significant reduction (<3% with sucrose and maltose) in transfection
efficiency when compared to pDNA dissolved in water. We demonstrate that disaccharides, like sucrose and trehalose, are effective
lyoprotectants for naked pDNA. 相似文献
3.
The effect of microenvironment pH, humidity, and temperature was evaluated on the stability of polymorphic and amorphous forms
of clopidogrel bisulfate, when present alone or in combinations. Oxalic acid and sodium carbonate were used as solid stressors
to create acidic and alkaline pH, respectively. The samples without and with stressors were subjected for 3 months to (1)
0% RH, 25% RH, 75% RH, and 85% RH at 40°C and also to (2) 60°C, 80°C, and 100°C at 0% RH. In case of solid samples without
stressors, the mixture of polymorphic and amorphous forms showed more degradation than the individual forms above critical
relative humidity (85% RH). Similar higher degradation was observed between 75% RH and 85% RH in case of acid-stressed samples.
In alkaline microenvironment, all the samples showed identical decomposition attributed to conversion of bisulfate salt to
free base. Thermal studies indicated that polymorphic forms of clopidogrel bisulfate and also its glassy amorphous form were
highly resistant to temperature, whereas the rubbery state of the drug degraded significantly at temperatures of ≥80°C. 相似文献
4.
The effect of humidity on the physicochemical properties of amorphous forms of cimetidine was investigated using differential
scanning calorimetry, isothermal microcalorimetry, and x-ray diffraction analysis. Amorphous forms were obtained by the melting
(amorphous form M [AM]) and the cotton candy (amorphous form C [AC]) methods. Thermal behaviors of AM and AC with or without
seed crystals were measured using an isothermal microcalorimeter under various conditions of relative humidity (RH) and temperature,
respectively. The crystallization kinetics of amorphous solids was analyzed based on 10 kinds of solid-state reaction models.
AM transformed into form A at 11% RH, 50°C but transformed into a mixture of form A and monohydrate at 51% and 75% RH at 25°C.
The mean crystallization times (MCTs) of the heat flow curve of AM and AC at 11% RH, 50°C were 47.82 and 32.00 hours, respectively,
but at 11% RH, 25°C both were more than 4320 hours. In contrast, AC transformed into form A under all storage conditions.
The MCTs of AC at 51% and 75% RH were 29.61 and 11.81 hours, respectively; whereas the MCTs of AM were 46.79 and 15.52 hours,
respectively. The crystallization of amorphous solids followed the three-dimensional growth of nuclei (Avrami equation) with
an induction period (IP). The IP for AM at 11% RH, 50°C was more than 2 times that for AC, but the difference in the crystal
growth rate constant (CR) between AC and AM was within 10%. The IP for AM at 75% RH, 25°C was reduced to only 10% of the IP
at 51% RH with increasing humidity, but the CR did not change significantly. In contrast, the IP for AC was slightly reduced
at 75% RH compared with 51% RH, but the CR was about 5 times greater. At 75% RH, 25°C, the IP and CR of AM were about one-fourth
the values of AC. This result suggests that the crystallization process consists of an initial stage during which the nuclei
are formed and a final stage of growth. 相似文献
5.
Melanie Köllmer Carmen Popescu Prashanth Manda Leon Zhou Richard A. Gemeinhart 《AAPS PharmSciTech》2013,14(4):1333-1340
Pharmaceutical excipients contain reactive groups and impurities due to manufacturing processes that can cause decomposition of active drug compounds. The aim of this investigation was to determine if commercially available oral disintegrating tablet (ODT) platforms induce active pharmaceutical ingredient (API) degradation. Benzocaine was selected as the model API due to known degradation through ester and primary amino groups. Benzocaine was either compressed at a constant pressure, 20 kN, or at pressure necessary to produce a set hardness, i.e., where a series of tablets were produced at different compression forces until an average hardness of approximately 100 N was achieved. Tablets were then stored for 6 months under International Conference on Harmonization recommended conditions, 25°C and 60% relative humidity (RH), or under accelerated conditions, 40°C and 75% RH. Benzocaine degradation was monitored by liquid chromatography–mass spectrometry. Regardless of the ODT platform, no degradation of benzocaine was observed in tablets that were kept for 6 months at 25°C and 60% RH. After storage for 30 days under accelerated conditions, benzocaine degradation was observed in a single platform. Qualitative differences in ODT platform behavior were observed in physical appearance of the tablets after storage under different temperature and humidity conditions. 相似文献
6.
The aim of this study was to investigate under a controlled environment, the effect of temperature on the survival and infectivity
of Pseudotheraptus devastans Distant, a cassava anthracnose disease vector. The insect P. devastans was collected from young cassava (Manihot esculenta Crantz) field plots, at the International Institute of Tropical Agriculture, (IITA), Ibadan, Nigeria. A mixture of the different
developmental stages of eggs, first to fifth instar nymphs, and adults, were incubated in controlled environment chambers,
under various constant temperatures of: 15, 17, 22, 25, 27, 30, and 35°C. Relative humidity at different temperature conditions
were recorded and maintained at 90%, 85%, 80%, 75%, 70%, 65%, and 60%, respectively. A significant increase in insect survival
was observed between 22 and 27°C temperature conditions while a significant decrease in survival was observed at 15°C and
above 30°C. Lesion number, lesion diameter and infectivity among the insect stages varied as a function of temperature and
relative humidity. Infectivity was highest at 22–25°C maintained at 75–80% RH and lowest at 15°C and above 30°C maintained
respectively, at 65% RH and 90% RH. There was considerable low vector infectivity due to low survival of the insects at extreme
temperatures. 相似文献
7.
The purpose of this study was to evaluate the physicochemical stability of carbohydrate-anchored liposomes. In the present
study, carbohydrate (galactose, fucose, and mannose) was palmitoylated and anchored on the surface of positively charged liposomes
(PL). The stabilities of plain neutral liposomes (NL), PL, and O-palmitoyl carbohydrate-anchored liposomes were determined.
The effects of storage conditions (4°C±2°C, 25°C±2°C/60%±5% relative humidity [RH], or 40°C±2°C/75%±5% RH for a period of
10, 20, and 30 days) were observed on the vesicle size, shape, zeta potential, drug content, and in vitro ligand agglutination
assay by keeping the liposomal formulations in sealed ambercolored vials (10-mL capacity) after flushing with nitrogen. The
stability of liposomal formulations was found to be temperature dependent. All the liposomal formulations were found to be
stable at 4°C±2°C up to 1 month. Storage at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5% RH adversely affected uncoated liposomal
formulations. Carbohydrate coating of the liposomes could enhance the stability of liposomes at 25°C±2°C/60%±5% RH and 40°C±2°C/75%±5%
RH.
Published: May 18, 2007 相似文献
8.
The objective of this study was to characterize the moisture sorption of magnesium stearate and the morphological changes, if any, resulting from moisture sorption. Six samples of commercial magnesium stearate USP were examined. Moisture sorption isotherms were obtained at 25°C and 5% to 98% relative humidity (RH) using a moisture balance. Changes in crystal form resulting from moisture sorption were determined by x-ray diffraction. There were differences in the shape of the isotherm, reversibility of moisture uptake, and shape of the hysteresis loop in the isotherms of crystalline and amorphous magnesium stearates. The isotherm of crystalline magnesium stearate was almost parallel to the pressure axis until and RH of ∼80%. The isotherm of the amorphous sample was characterized by continuous uptake of water over the entire range of RH. Exposure of amorphous magnesium stearate to RH greater than 70% resulted in the formation of the trihydrate. The trihydrate was converted into the anhydrous form when heated to a temperature of 100°C to 105°C. The trihydrate could be generated by exposing the anhydrate to RH higher than 70%. 相似文献
9.
An operon, bglABC, that encodes two sugar permeases and a β-glucosidase was cloned from a cellulolytic actinomycete, Thermobifida fusca, into Escherichia coli and sequenced. The bglC gene encoding an intracellular β-glucosidase (β-d-glucoside glucohydrolase, EC 3.2.1.21) belonging to glycosyl hydrolase
family 1 was subcloned and expressed in E. coli. The purified enzyme (MW 53,407 Da; pI 4.69) hydrolyzed substrates containing both β 1 → 4 and β 1 → 2 glycosidic bonds,
and was most active against cellobiose (Vmax= 29, K
m
= 0.34 mm), cellotriose, cellotetraose, and sophorose. The enzyme also showed aryl-β-glucosidase activity on p-nitrophenyl-β-d-glucopyranoside and p-nitrophenyl-β-d-cellobioside. BglC had a pH optimum of 7.0 and a temperature optimum
of 50°C. The enzyme was stable at 60°C, but was rapidly inactivated at 65°C. BglC was inhibited by low concentrations of gluconolactone,
but was insensitive to end-product inhibition by glucose and was not affected by Ca or Mg ions or EDTA. Its properties are
well suited for use in a process to hydrolyze biomass cellulose to glucose.
Received: 21 August 2000 / Accepted: 4 October 2000 相似文献
10.
Extracellular heat-shock protein 72 (eHsp72) expression during exercise-heat stress is suggested to increase with the level
of hyperthermia attained, independent of the rate of heat storage. This study examined the influence of exercise at various
intensities to elucidate this relationship, and investigated the association between eHsp72 and eHsp27. Sixteen male subjects
cycled to exhaustion at 60% and 75% of maximal oxygen uptake in hot conditions (40°C, 50% RH). Core temperature, heart rate,
oxidative stress, and blood lactate and glucose levels were measured to determine the predictor variables associated with
eHsp expression. At exhaustion, heart rate exceeded 96% of maximum in both conditions. Core temperature reached 39.7°C in
the 60% trial (58.9 min) and 39.0°C in the 75% trial (27.2 min) (P < 0.001). The rate of rise in core temperature was 2.1°C h−1 greater in the 75% trial than in the 60% trial (P < 0.001). A significant increase and correlation was observed between eHsp72 and eHsp27 concentrations at exhaustion (P < 0.005). eHsp72 was highly correlated with the core temperature attained (60% trial) and the rate of increase in core temperature
(75% trial; P < 0.05). However, no common predictor variable was associated with the expression of both eHsps. The similarity in expression
of eHsp72 and eHsp27 during moderate- and high-intensity exercise may relate to the duration (i.e., core temperature attained)
and intensity (i.e., rate of increase in core temperature) of exercise. Thus, the immuno-inflammatory release of eHsp72 and
eHsp27 in response to exercise in the heat may be duration and intensity dependent. 相似文献
11.
Susceptibility of the cigarette beetle Lasioderma serricorne (Coleoptera: Anobiidae) to hypoxia 总被引:2,自引:0,他引:2
The susceptibility of the cigarette beetle Lasioderma serricorne (F.) to hypoxia was examined at three different oxygen concentrations (0.5?C0.8, 1.0?C1.3, and 2.0?C2.3?%) and four different temperature/humidity (RH) conditions: 30?°C/75?% RH, 25?°C/75?% RH, 20?°C/43?% RH, and 15?°C/43?% RH. The influence of humidity on mortality was also examined at three humidity levels (21, 43, and 75?% RH) at 1.0?C1.3?% oxygen (O2) and 25?°C. Our results revealed that adult beetles were the most tolerant at 2.0?C2.3?% O2 and that the larvae were the most tolerant at O2 levels <1.0?C1.3?%. Mortality increased with increasing temperatures and decreasing O2 concentrations. At 30?°C, 75?% RH, and 0.5?C0.8?% O2, the 99?% lethality (LT99) of larvae was 6.9?days; however, it increased to 20?days when the temperature was decreased to 25?°C or when O2 levels were increased to 1.0?C1.3?%. Humidity also influenced mortality of both larval and adult beetles. LT99 values for larvae at 25?°C and 1.0?C1.3?% O2 were 24.0, 44.6, and 50.2?days at 21, 43, and 75?% RH, respectively. Results of this study indicate that a controlled atmosphere (CA) with reduced oxygen levels (<0.5?C0.8?% O2) represents an effective measure for disinfesting stored tobacco as an alternative to conventional phosphine fumigation at temperatures >30?°C. 相似文献
12.
Beatriz Galán Concepción García Mendoza Myriam Calonje Monique Novaes-Ledieu 《Current microbiology》1999,38(3):190-193
Agaricus bisporus H 25 produced extracellular endo-1,3-β-glucanase when grown in a static culture at 25°C in a minimal synthetic medium supplemented
with A. bisporus cell walls plus fructose. Endo-1,3-β-glucanase was purified 17.85-fold from 20-day-old culture filtrates by precipitation
at 80% ammonium sulfate saturation, Sephadex G-75 gel filtration, and preparative PAGE followed by electroelution. The purified
enzyme yielded a single band in both native and SDS-polyacrylamide gels with a molecular mass of 32 kDa (SDS-PAGE) and 33.7
kDa (MALDI-MS), showing an isoelectric point of 3.7. The enzyme was active against β-1,3- linkages and, to a lesser extent,
against β-1,6-, exhibiting an endohydrolytic mode of action and a glycoprotein nature. Significant activities of the endo-glucanase
against laminarin and pustulan were observed between pH 4 and 5.5, and between 40° and 50°C for laminarin, and between 30°
and 50°C for pustulan. The optimum pH and temperature were 4.5 and 45°C for both substrates.
Received: 17 June 1998 / Accepted: 24 September 1998 相似文献
13.
Badawi A. Abou-Awad Mahmoud M. Al-Azzazy Sahar I. Afia 《Archives Of Phytopathology And Plant Protection》2013,46(19):1862-1866
Studies on biology of Oligonychus mangiferus (Rahman and Sapra) at combination of eight constant temperatures and relative humidities (RHs) viz., 7.0°C with 85% RH, 10°C with 80% RH, 15.0°C with 75% RH, 23.0°C with 70% RH, 31.0°C with 65% RH, 34.0°C with 65% RH, 36.0°C with 60% RH and 40.0°C with 55% RH revealed that the optimal condition for the development of these mites are 15.0–31.0°C and 65–75% RH. The highest temperature and the lowest RH accelerated the rate of development and induced more reproduction of O. mangiferus. Its population also multiplied 30.81 times in a generation time of 27.36 days at 31.0°C and 65% RH, while the same population only increased 7.46 times in a generation time of 48.07 days at 15.0°C and 75% RH. Fecundity was highest at 31.0°C and 65% RH with 46.43 eggs per female. The highest intrinsic rate of natural increase was observed at 31.0°C as 0.125 per day. 相似文献
14.
Jarrod W. Collier Rakhi B. Shah Abhay Gupta Vilayat Sayeed Muhammad J. Habib Mansoor A. Khan 《AAPS PharmSciTech》2010,11(2):818-825
Stability of formulations over shelf-life is critical for having a quality product. Choice of excipients, manufacturing process,
storage conditions, and packaging can either mitigate or enhance the degradation of the active pharmaceutical ingredient (API),
affecting potency and/or stability. The purpose was to investigate the influence of processing and formulation factors on
stability of levothyroxine (API). The API was stored at long-term (25°C/60%RH), accelerated (40°C/75%RH), and low-humidity
(25°C/0%RH and 40°C/0%RH) conditions for 28 days. Effect of moisture loss was evaluated by drying it (room temperature, N2) and placed at 25°C/0%RH and 40°C/0%RH. The API was incubated with various excipients (based on package insert of marketed
tablets) in either 1:1, 1:10, or 1:100 ratios with 5% moisture at 60°C. Commonly used ratios for excipients were used. The
equilibrium sorption data was collected on the API and excipients. The API was stable in solid state for the study duration
under all conditions for both forms (potency between 90% and 110%). Excipients effect on stability varied and crospovidone,
povidone, and sodium laurel sulfate (SLS) caused significant API degradation where deiodination and deamination occurred.
Moisture sorption values were different across excipients. Crospovidone and povidone were hygroscopic whereas SLS showed deliquescence
at high RH. The transient formulation procedures where temperature might go up or humidity might go down would not have major
impact on the API stability. Excipients influence stability and if possible, those three should either be avoided or used
in minimum quantity which could provide more stable tablet formulations with minimum potency loss throughout its shelf-life. 相似文献
15.
D'Souza David R. Morgan Richard D. Parashar Vijay Capalash Neena Sharma Prince 《World journal of microbiology & biotechnology》2004,20(6):593-598
A thermophile, isolated from geothermal areas in the northern Himalayan region of India, was identified by partial 16S rDNA
sequence (GenBank accession # AF482430) analysis as Anoxybacillus flavithermus. The isolate produced BflI (REBASE # 4910), a Type II restriction endonuclease, which recognized the sequence 5′-CCNNNNN/NNGG-3′ and was the isoschizomer
of BsiYI. The enzyme was purified to homogeneity by passing through Cibacron Blue F3GA agarose, DEAE-cellulose, heparin-agarose
and MonoQ FPLC. The purified enzyme (MW 36 kDa) worked best at 60 °C in Promega's buffer C and preferentially required Co++(0.4 mM) as cofactor followed by Mg++(10 mM) and Mn++(1 mM). The enzyme showed high specific activity and worked in the presence of high concentrations of β-mercaptoethanol (200
mM), Triton-X-100 (25%), urea (30%), formamide (6%) and guanidine (40 mM) and showed no star activity in the presence of 40%
glycerol. In the absence of any stabilizing agent, BflI retained t
1/2 for at least 96 h at 37 °C, 6 h at 60 °C and 6 months at 4 °C. N-terminal sequencing showed that its first 10 amino acid
residues were DFHEDKTIAR.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Effect of vacuum drying on protein-mannitol interactions: The physical state of mannitol and protein structure in the dried state 总被引:1,自引:0,他引:1
The purpose of the present studies was to systematically investigate protein-mannitol interactions using vacuum drying, to
obtain a better understanding of the effect of protein/mannitol wt/wt ratios on the physical state of mannitol and protein
secondary structure in the dried state. Solutions containing β-lactoglobulin (βLg):mannitol (1∶1–1∶15 wt/wt) were vacuum dried
at 5°C under 3000 mTorr of pressure. The physical state of mannitol was studied using x-ray powder physical state of mannitol
was studied using x-ray powder diffractometry (XRPD), polarized light microscopy (PLM), Fourier-transform infrared (FTIR)
spectroscopy, and modulated differential scanning calorimetry (MDSC). XRPD studies indicated that mannitol remained amorphous
up to 1∶5 wt/wt βLg:mannitol ratio, whereas PLM showed the presence of crystals of mannitol in all dried samples except for
the 1∶1 wt/wt βLg:mannitol dried sample. FITR studies indicated that a small proportion of crystalline mannitol was present
along with the amorphous mannitol in dried samples at lower (less than 1∶5 wt/wt) βLg:mannitol ratios. The Tg of the dried 1∶1 wt/wt βLg:mannitol sample was observed at 33.4°C in MDSC studies, which indicated that at least a part of
mannitol co-existed with protein in a single amorphous phase. Evaluation of the crystallization exotherms indicated that irrespective
of the βLg:protein wt/wt ratio in the initial sample, the protein to amorphous mannitol ratio was below 1∶1 wt/wt in all dried
samples. Second-derivative FTTR studies on dried βLg and recombinant human interferon α-2a samples showed that mannitol affected
protein secondary structure to a varying degree depending on the overall mannitol content in the dried sample and the type
of protein. 相似文献
17.
An extremely halotolerant mannan-degrading bacterium (strain NN) was isolated from the Great Salt Lake, Utah, USA. Strain
NN grew at salinities from 0 to 20% NaCl with optimal growth at 0% NaCl. When grown on 0.2% (w/v) locust bean gum as the carbon
source at 10% NaCl, both β-mannanase and β-mannosidase activities were produced. β-Mannosidase activity was shown to be cell-associated,
while at least 23% of the total β-mannanase activity was extracellular. The optimum temperature and pH for β-mannanase activity
were 70 °C and 7.6, and for β-mannosidase 25 °C and 7.0. The β-mannanase system retained full activity after 24 h of incubation
at 60 °C and 10% NaCl. β-Mannanase activity was maximal at 1% NaCl and β-mannosidase activity at 0.5% NaCl. Despite these
low salinity optima, 50% and 100% respectively of the initial β-mannanase and β-mannosidase activities remained after 48 h
of incubation at 20% NaCl, indicating a high degree of halostability. Sodium dodecyl sulphate/polyacrylamide gel electrophoresis
revealed the presence of at least eight different mannan-degrading proteins in the cell-free culture supernatant of cultures
grown on locust bean gum.
Received: 19 March 1998 / Received revision: 8 June 1998 / Accepted: 14 June 1998 相似文献
18.
Isabella Di Lernia Alessandra Morana Antonio Ottombrino Stefania Fusco Mosè Rossi M. De Rosa 《Extremophiles : life under extreme conditions》1998,2(4):409-416
Enzymes that convert starch and dextrins to α,α-trehalose and glucose were found in cell homogenates of the hyperthermophilic
acidophilic archaeon Sulfolobus shibatae DMS 5389. Three enzymes were purified and characterized. The first, the S. shibatae trehalosyl dextrin-forming enzyme (SsTDFE), transformed starch and dextrins to the corresponding trehalosyl derivatives with
an intramolecular transglycosylation process that converted the glucosidic linkage at the reducing end from α-1,4 to α-1,1.
The second, the S. shibatae trehalose-forming enzyme (SsTFE), hydrolyzed the α-1,4 linkage adjacent to the α-1,1 bond of trehalosyl dextrins, forming
trehalose and lower molecular weight dextrins. These two enzymes had molecular masses of 80 kDa and 65 kDa, respectively,
and showed the highest activities at pH 4.5. The apparent optimal temperature for activity was 70°C for SsTDFE and 85°C for
SsTFE. The third enzyme identified was an α-glycosidase (SsαGly), which catalyzed the hydrolysis of the α-1,4 glucosidic linkages
in starch and dextrins, releasing glucose in a stepwise manner from the nonreducing end of the polysaccharide chain. The enzyme
had a molecular mass of 313 kDa and showed the highest activity at pH 5.5 and at 85°C.
Received: October 29, 1997 / Accepted: April 29, 1998 相似文献
19.
Anthocoris minki Dohrn is a promising indigenous Anthocoris species for the biological control of Agonoscena pistaciae Burck. and Laut. (Homoptera: Psyllidae) in pistachio orchards in Turkey. The adult longevity, fecundity, life table parameters
and prey consumption of A. minki fed on Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs were studied at combinations of three constant temperatures (20, 25 and 30 ± 1°C) with
two relative humidity (RH) levels (40 and 65 ± 5%). Studies indicated that temperature and RH significantly affected adult
longevity, fecundity and prey consumption of A. minki. The greatest adult female longevity was 116.0 days at 20°C and 65% RH; the shortest adult female longevity was 27.5 days
at 30°C and 40% RH. At all tested temperatures, the oviposition period and prey consumption of both females and males significantly
decreased at low RH compared to high RH. The highest and lowest total fecundities were 276.0 eggs (at 20°C and 65% RH) and
42.4 eggs (at 25°C and 40% RH), respectively. The intrinsic rates of natural increase (r
m) at 40 and 65% RH were 0.049 and 0.076 at 20°C, 0.072 and 0.096 at 25°C and 0.076 and 0.112 at 30°C, respectively. The highest
mean numbers of E. kuehniella eggs consumed by females and males were 859.6 (at 20°C) and 515.3 (at 25°C) at 65% RH, respectively; the lowest were 183.3
(at 20°C) and 95.5 (at 25°C) at 40% RH, respectively. 相似文献
20.
The protein secondary structure and pigments' microenvironment in photosystem 1 (PS1) complexes were studied in the temperature
range of 25–80 °C using Fourier transform infrared (FT-IR) and circular dichroism (CD) spectroscopy, respectively. Quantitative
analysis of the component bands of the amide I band (1 700–1 600 cm−1) showed no significant change below 50 °C. However, apparent conformational changes occurred at 60 °C and further continued
at 70 and 80 °C accompanied with transitions of secondary structure mainly from α-helix to the β-sheet structures. CD analysis
demonstrated that the regular arrangement, viz. protein microenvironment of pigments of PS1 complexes, was destroyed by heat
treatment which might come from the changes of protein secondary structure of PS1. The CD signals at 645 nm contributed by
chlorophyll (Chl) b of light-harvesting complex 1 (LHC1) were easily destroyed at the beginning of heat treatment (25–60 °C). When temperature
reached 70 and 80 °C, the CD signals at 478 nm contributed mainly by Chl b of LHC1 and 498 nm contributed by carotenoids decreased most rapidly, indicating that LHC1 was more sensitive to high temperature
than core complexes. In addition, the oxygen uptake rate decreased by 90.81 % at 70 °C and was lost completely at 80 °C showing
that heat treatment damaged the regular function of PS1 complexes. This may be attributed to heat-induced changes of pigment
microenvironment and protein secondary structure, especially transmembrane α-helix located in PsaA/B of PS1. 相似文献