N., and Bakry, N. M. (2006)

Yamagiwa, Noriyuki, Abiko, Yumi, Sugita, Mari, Tian, Jun, Matsunaga, Shigeki, and Shibasaki, Masakatsu (2006). Catalytic asymmetric cyano-phosphorylation of aldehydes using a YLi3tris(binaphthoxide) complex (YLB): Asymmetric Catalysis. Tetrahedron: Asymmetry 17: 566-573.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

A highly enantioselective cyano-phosphorylation of aldehydes catalyzed by a YLi3tris(binaphthoxide) complex YLB 1 is described. The slow addition of diethyl cyanophosphonate 4 to aldehydes 5 in the presence of YLB 1 (10 mol %), H2O (30 mol %), tris(2,6-dimethoxyphenyl)phosphine oxide 3a (10 mol %), and BuLi (10 mol %) afforded cyanohydrin O-phosphates 6 in up to 98% yield and 97% ee. Mechanistic studies revealed that the addition of cyanide to aldehydes is irreversible and determines the enantioselectivity. The reaction mechanism is also discussed in detail.

Yamamoto, Kagetoshi, Matsue, Yuji, Hara, Osamu, and Murata, Ichiro (1982). The chemistry of phenalenium systems XXXIII. The Dibenzo[de;thi]naphthacenyl dication and the dianon. Tetrahedron Letters 23: 877-880.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

The dibenzo[de;hi]naphthacenyl dication () and dianion () have been generated from a mixture of the corresponding precursor hydrocarbons. The pmr spectra of and indicated that the positive and the negative charges were found to be fully delocalized over the molecules, respectively, consistent with the C2v-symmetry structures. The pmr chemical shifts of correlate well with the Huckel charge densities.

Yanai, Hikaru and Taguchi, Takeo (2005). Indium(III) triflate catalyzed tandem azidation/1,3-dipolar cycloaddition reaction of [omega],[omega]-dialkoxyalkyne derivatives with trimethylsilyl azide. Tetrahedron Letters 46: 8639-8643.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

The azidation reaction of dialkyl acetal derivatives with trimethylsilyl azide (TMSN3) was efficiently catalyzed by 1-5 mol % of In(OTf)3. The major product differed depending on the substrate structure and molar ratio of TMSN3, that is, aliphatic acetals provided [alpha]-azido ether derivatives, while aromatic acetal (benzaldehyde dimethyl acetal) provided gem-diazide, respectively. Furthermore, novel tandem azidation/1,3-dipolar cycloaddition reaction using alkynyl acetal derivatives gave bicyclic triazolo-heterocyclic compounds, recognized as chemically modified aza-sugar analogues, in high yields under mild conditions. Indium(III) triflate/ Azidation/ 1,3-Dipolar cycloaddition/ Tandem reaction/ Triazolo-heterocyclic compounds

Yang, Li, Zhao, Yu-hua, Zhang, Bing-xin, Yang, Ching-Hong, and Zhang, Xin (2005). Isolation and characterization of a chlorpyrifos and 3,5,6-trichloro-2-pyridinol degrading bacterium. FEMS Microbiology Letters 251: 67-73.
Chem Codes: Chemical of Concern: DZ Rejection Code: BACTERIA.

A bacterium, isolated from contaminated soils around a chemical factory and named strain DSP3 was capable of biodegrading both chlorpyrifos and 3,5,6-trichloro-2-pyridinol. Based on the results of phenotypic features, phylogenetic similarity of 16S rRNA gene sequences, DNA G + C content, and DNA homology between strain DSP3 and reference strains, strain DSP3 was identified as Alcaligenes faecalis. Chlorpyrifos was utilized as the sole source of carbon and phosphorus by strain DSP3. We examined the role of strain DSP3 in the degradation of chlorpyrifos and 3,5,6-trichloro-2-pyridinol under different culture conditions. Parathion and diazinon could also be degraded by strain DSP3 when provided as the sole sources of carbon and phosphorus. An addition of strain DSP3 (108 cells g-1) to soil with chlorpyrifos (100 mg kg-1) resulted in a higher degradation rate than the one obtained from non-inoculated soils. Different degradation rates of chlorpyrifos in six types of treated soils suggested that soils used for cabbage growing in combination with inoculation of strain DSP3 showed enhanced microbial degradation of chlorpyrifos. Chlorpyrifos degrading bacterium/ 3,5,6-Trichloro-2-pyridinol degrading/ Rhizosphere/ Alcaligenes faecalis

Yang, Raymond S. H., Dauterman, Walter C., and Hodgson, Ernest (1969). Enzymatic degradation of diazinon by rat liver microsomes. Life Sciences 8: 667-672.
Chem Codes: Chemical of Concern: DZ Rejection Code: METABOLISM.

A method was developed to study the metabolism of diazinon by rat liver preparations. Preliminary results showed that diazinon is rapidly degraded into diethyl phosphorothioic and diethyl phosphoric acids by a rat liver microsomal enzyme system requiring NADPH and oxygen. These findings and the inhibition by carbon monoxide strongly suggest the involvement of cytochrome P450, the carbon monoxide binding pigment. The enzyme system is found to be more active in Tris buffer than in phosphate buffer. Oxidative degradation appears to be the major route of metabolism of diazinon.

Yang, T. and Zhang, F. (1989). Acute Toxicity of 7 Pesticides on 2 Species of Common Leeches. China Environ.Sci.(Zhongguo Huanjing Kexue) 9: 51-55 (CHI) (ENG ABS).

EcoReference No.: 3234

Chemical of Concern: CuS,NaPCP,DZ,HCCH,MLN,DDVP; Habitat: A; Effect Codes: MOR; Rejection Code: NO FOREIGN.

YASOSHIMA, M. and MASUDA, Y. (1986). EFFECT OF CARBON DISULFIDE ON THE ANTICHOLINESTERASE ACTION OF SEVERAL ORGANOPHOSPHORUS INSECTICIDES IN MICE. TOXICOL LETT (AMST); 32: 179-184.

Chem Codes: Chemical of Concern: DMT Rejection Code: IN VITRO.

BIOSIS COPYRIGHT: BIOL ABS. RRM LIVER DIMETHOATE DIAZINON PARATHION PHENOBARBITAL PRETREATMENT Biochemistry/ Metabolism/ Digestive System/ Digestive System Diseases/Pathology/ Digestive System/Pathology/ Pharmaceutical Preparations/Metabolism/ Poisoning/ Animals, Laboratory/ In Vitro/ Tissue Culture/ Herbicides/ Pest Control/ Pesticides/ Muridae

Yasuno, M., Hirakoso, S., Sasa, M., and Uchida, M. (1965). Inactivation of Some Organophosphorous Insecticides by Bacteria in Polluted Water. Jpn.J.Exp.Med. 35: 545-563.

EcoReference No.: 15271

Chemical of Concern: DZ; Habitat: A; Rejection Code: NO COC(DZ).

Yasuno, M. and Kerdpibule, V. (1967). Susceptibility of Larvae of Culex pipiens fatigans to Organophosphorous Insecticides in Thailand. Jpn.J.Exp.Med. 37: 559-562 .

EcoReference No.: 17127

Chemical of Concern: DZ,MLN,DDVP,FNTH; Habitat: A; Effect Codes: MOR; Rejection Code: NO CONTROL(ALL CHEMS).

Yasutomi, K. and Takahashi, M. (1987). Insecticidal resistance of Culex tritaeniorhynchus (Diptera: Culicidae) in Japan: A country-wide survey of resistance to insecticides. Journal of Medical Entomology [J. MED. ENTOMOL.]. Vol. 24, no. 6, pp. 604-608. 1987.

Chem Codes: Chemical of Concern: DZ Rejection Code: SURVEY.

ISSN: 0022-2585

Descriptors: pesticide resistance
Descriptors: geographical variations
Descriptors: Culicidae
Descriptors: Japan
Abstract: Sixteen samples of Culex tritaeniorhynchus Giles collected in 14 prefectures in Japan in 1984 were assessed for resistance to insecticides. All of the samples were highly resistant to organophosphorus (OP) and carbamate insecticides, but none was resistant to a pyrethroid (permethrin). Resistance levels for each of the OP's and carbamates were similar among samples except for diazinon and temephos. Considerable variation in LC sub(50)'s of temephos may have resulted from exposure to other OP's used for crop protection because temephos has not been used in ricefields in Japan.
Language: English
English
Publication Type: Journal Article
Classification: Z 05219 Population genetics
Classification: Z 05206 Medical & veterinary entomology
Classification: Z 05183 Toxicology & resistance
Subfile: Entomology Abstracts

Yasutomi, K. and Takahashi, M. (1987). Insecticidal Resistance of Culex tritaeniorhynchus (Diptera: Culicidae) in Japan: A Country-Wide Survey of Resistance to Insecticides. J Med Entomol 24: 604-608 .

Chem Codes: Chemical of Concern: DZ Rejection Code: SURVEY.

YENIGUN, O. and SOHTORIK, D. (1995). Calculations with the level II fugacity model for selected organophosphorus insecticides. WATER AIR AND SOIL POLLUTION; 84 175-185.

Chem Codes: Chemical of Concern: DZ Rejection Code: MODELING.

BIOSIS COPYRIGHT: BIOL ABS. The environmental equilibrium distributions and levels of persistency of 20 selected organophosphorus insecticides have been determined using Mackay's Level II Fugacity Model. The model comprised air, water, biota, soil, suspended solids and sediment compartments. Available physicochemical and kinetic data for the insecticides have been compiled. Results suggest that some of the insecticides have tendencies to occur at high concentrations in biota and may be environmentally persistent. Mathematics/ Statistics/ Biology/ Ecology/ Climate/ Ecology/ Meteorological Factors/ Ecology/ Oceanography/ Fresh Water/ Biophysics/ Cybernetics/ Air Pollution/ Soil Pollutants/ Water Pollution/ Soil

Yielding, L. W., Graves, D. E., Brown, B. R., and Yielding, K. L. (1979). Covalent binding of ethidium azide analogs to DNA : Competition by ethidium bromide. Biochemical and Biophysical Research Communications 87: 424-432.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

The photoreactive analogs of ethidium bromide (ethidium mono- and diazide) have been developed as drug probes to determine the actual molecular details of ethidium bromide interactions with DNA. In an effort to demonstrate that the analogs in fact mimic the parent ethidium, competition experiments were designed using 3H thymidine-labeled DNA in intact TA1538, which is reverted by the azide analogs. 14C-labeled ethidium azide analogs were used in combination with the non-labeled ethidium bromide. The results presented here demonstrate that the parent ethidium competes with the azide analogs as a DNA intercalating drug using CsCl density gradient ultracentrifugation.

Yielding, Lerena W., Brown, Brenda R., Graves, David E., and Lemone Yielding, K. (1979). Ethidium bromide enhancement of frameshift mutagenesis caused by photoactivatable ethidium analogs. Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 63: 225-232.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

Ethidium azide analogs (3-amino-8-azido-ethidium monoazide and ethidium diazide) have been developed as photosensitive probes in order to analyze directly the reversible in vivo interactions of ethidum bromide. Our preliminary observation [11], relating the mutagenic potential of the monoazide analog of ethidium, have been extended and refined, using the highly purified ethidium azide analogs [5].A number of physical-chemical studies indicate that the monoazide analog interaction with nucleic acids, prior to photolysis, resembles remarkably the interaction of the parent ethidium (unpublished). It was anticipated, therefore, that competition by ethidium for the ethidium monoazide mutagenic sites in Salmonella TA1538 would be observed when these drugs were used in combination. Previous results in fact showed a decreased production of frameshift mutants when ethidium bromide was added to the ethidium monoazide in the Ames assay [11]. However, more extensive investigations, reported here, have shown that this apparent competition was the result of neglecting the toxic effects of ethidium monoazide and its enhanced toxicity in the presence of ethidium bromide. Conversely, an enhancement of the azide mutagenesis and toxicity for both the mono- and diazide analogs was seen when ethidium bromide was used in combination with these analogs.

Yokoyama, Masataka, Matsushita, Michio, Hirano, Sachiko, and Togo, Hideo (1993). Synthesis of 6-oxa-1,5-pentamethylenetetrazoles (sugar tetrazoles). Tetrahedron Letters 34: 5097-5100.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

Some sugar tetrazoles have been synthesized by the photolysis or the thermolysis of -glucopyranosylidene diazide of -galactopyranosylidene diazide. The reaction mechanism is discussed.

Yokoyama, T., Saka, H., Fujita, S., and Nishiuchi, Y. (1988). Sensitivity of Japanese Eel, Anguilla japonica, to 68 Kinds of Agricultural Chemicals. Bull.Agric.Chem.Insp.Stn. 28: 26-33 (JPN) (ENG ABS).

EcoReference No.: 8570

Chemical of Concern: ACP,Captan,CBL,CTN,DMT,DS,DZ,FO,HXZ,MDT,MLN,MOM,PPG,PSM,TET,CYP,FVL,PMR,TFR,Cu,CuS,PCP,IZP,MCPP1; Habitat: A; Effect Codes: MOR; Rejection Code: NO FOREIGN.

Yon, Jei-Oh, Nakamura, Hidemitsu, Ohta, Akinori, and Takagi, Masamichi (1998). Incorporation of extracellular phospholipids and their effect on the growth and lipid metabolism of the Saccharomyces cerevisiae cho1/pss mutant. Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism 1394: 23-32.

Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

The cho1/pss mutant of Saccharomyces cerevisiae, which is auxotrophic for choline or ethanolamine because of the deficiency in phosphatidylserine synthesis, grew in the presence of 0.05 mM phosphatidylcholine (PC) with octanoic acids (diC8PC) or decanoic acids (diC10PC), but not in the presence of PC with longer acyl residues. It did not grow in the presence of the soluble hydrolytic products of PC, phosphorylcholine or glycerophosphorylcholine, at comparable concentrations. Addition of 10 mM hemicholinium-3, a choline transport inhibitor, or disruption of the CTR gene, which encodes a choline transporter, inhibited the growth of the cho1/pss mutant in the presence of choline, but not in the presence of 0.1 mM diC8PC. Under diC8PC-supported growth conditions, octanoic acid was barely detectable in the cellular phospholipid fraction, but was recovered in the culture medium as the free acid, and the phosphatidylethanolamine (PE) content was low in comparison to the choline-supported conditions. These results suggest that PCs with short acyl residues were taken up by the cho1/pss mutant and remodeled as they were used, and that PCs with short acyl residues do not inhibit conversion of PE to PC. The current results provide a new direction in the analysis of intracellular phospholipid movement and metabolism in yeast. CHO1/ Phospholipid uptake/ Phosphatidylcholine/ Octanoic acid/ (Saccharomyces cerevisiae)

Yoo, J. K., Lee, S. W., Ahn, Y. J., Nagata, T., and Shono, T. (2002). Altered Acetylcholinesterase as a Resistance Mechanism in the Brown Planthopper (Homoptera: Delphacidae), Nilaparvata lugens Stal. Appl.Entomol.Zool. 37: 37-41.

EcoReference No.: 81967

Chemical of Concern: CBF,DZ; Habitat: T; Effect Codes: BCM,MOR; Rejection Code: TARGET(DZ).

Yoshioka, Y., Mizuno, T., Ose, Y., and Sato, T. (1986). The Estimation for Toxicity of Chemicals on Fish by Physico-chemical Properties. Chemosphere 15: 195-203 (OECDG).

EcoReference No.: 6600

Chemical of Concern: NYP,DZ; Habitat: A; Effect Codes: MOR; Rejection Code: NO REVIEW.

Young, Ku, Chang, Jay-Lin, Shen, Yung-Shuen, and Lin, Shi-Yow (1998). Decomposition of diazinon in aqueous solution by ozonation. Water Research 32: 1957-1963.

Chem Codes: Chemical of Concern: DZ Rejection Code: FATE.

ozonation/ diazinon/ organic phosphates

YOUNOS TM and WEIGMANN DL (1988). PESTICIDES A CONTINUING DILEMMA. J WATER POLLUT CONTROL FED; 60 1199-1205.
Chem Codes: Chemical of Concern: DZ Rejection Code: REVIEW.

BIOSIS COPYRIGHT: BIOL ABS. RRM REVIEW HERBICIDE INSECTICIDE FUNGICIDE ENVIRONMENTAL POLLUTANT REGULATION FEDERAL INSECTICIDE FUNGICIDE AND RODENTICIDE ACT Legislation/ Organization and Administration/ Biology/ Ecology/ Biochemistry/ Air Pollution/ Soil Pollutants/ Water Pollution/ Grasses/Growth & Development/ Soil/ Herbicides/ Pest Control/ Pesticides/ Arachnida/ Entomology/Economics/ Insecticides/ Pest Control/ Pesticides

Yu, Jya-Jyun (2002). Removal of organophosphate pesticides from wastewater by supercritical carbon dioxide extraction. Water Research 36: 1095-1101.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

Organophosphate pesticides including fenitrothion chlorpyrifos, diazinon, methamidophos, edifenphos, mevinphos, fenthion, and acephate present in agro-wastewater can be effectively removed by supercritical carbon dioxide (SC-CO2) extraction. Near quantitative removal of the pesticides from the aqueous solution can be achieved by SC-CO2 at 90[deg]C and 325 atm for 20 min of static extraction followed by 40 min of dynamic extraction. The extracted pesticides were collected in a small amount of Fenton's solution. The pesticides in Fenton's solution were degraded completely within an hour after the collection. A combination of SC-CO2 extraction and subsequent degradation by Fenton's reagent may provide an alternative water purification strategy for treating organophosphate pesticides in agro-wastewater. Organophosphate pesticides/ SC-CO2/ Extraction/ Degradation/ Fenton's reagent

Yu, S. J. (1991). Insecticide Resistance in the Fall Armyworm, Spodoptera frugiperda (J. E. Smith). Pestic.Biochem.Physiol. 39: 84-91.

EcoReference No.: 73599

Chemical of Concern: MOM,PMR,CYP,CYT,BFT,TMT,FVL,DZ,CPY,MP,CBL,TDC,DDVP,SPS,TLM,MLN,FNV; Habitat: T; Effect Codes: MOR; Rejection Code: OK TARGET(MLN,FVL,CYP,DZ),TARGET(BFT).

Yu, S. J. (1988). Selectivity of Insecticides to the Spined Soldier Bug (Heteroptera: Pentatomidae) and Its Lepidopterous Prey. J.Econ.Entomol. 81: 119-122.

EcoReference No.: 68973

Chemical of Concern: CPY,DZ; Habitat: T; Rejection Code: TARGET(DZ).

YUEH L-Y and HENSLEY DL (1990). PESTICIDE INFLUENCE ON NITROGEN FIXATION AND NODULATION BY SOYBEAN AND LIMA BEAN. 87TH ANNUAL MEETING OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE, TUCSON, ARIZONA, USA, NOVEMBER 4-8, 1990. HORTSCIENCE; 25 (9). 1990. 1145. AB - BIOSIS COPYRIGHT: BIOL ABS. RRM ABSTRACT GLYCINE-MAX PHASEOLUS-LUNATUS RHIZOBIUM PLANT BACTERIA MICROORGANISM DIAZINON TRIFLURALIN CROP INDUSTRY AGRICULTURE.

Chem Codes: Chemical of Concern: DZ Rejection Code: ABSTRACT.

Congresses/ Biology/ Biochemistry/ Metabolism/ Bacteria/Physiology/ Bacteria/Metabolism/ Soil Microbiology/ Biophysics/ Plants/Metabolism/ Oils/ Plants/Growth & Development/ Soil/ Vegetables/ Environmental Pollution/ Plant Diseases/ Weather/ Herbicides/ Pest Control/ Pesticides/ Rhizobiaceae/ Legumes

Zago, M. Paola and Oteiza, Patricia I. (2001). The antioxidant properties of zinc: interactions with iron and antioxidants. Free Radical Biology and Medicine 31: 266-274.
Chem Codes: Chemical of Concern: DZ Rejection Code: NO TOX DATA.

Potential mechanisms underlying zinc’s capacity to protect membranes from lipid oxidation were examined in liposomes. Using lipid oxidation initiators with different chemical and physical properties (transition metals, lipid- or water-soluble azo compounds, ultraviolet radiation c (UVc), superoxide radical anion (O2--), and peroxynitrite (ONOO-) we observed that zinc only prevented copper (Cu2+)- and iron (Fe2+)-initiated lipid oxidation. In the presence of Fe2+, the antioxidant action of zinc depended directly on the negative charge density of the membrane bilayer. An inverse correlation (r2: 0.96) was observed between the capacity of zinc to prevent iron binding to the membrane and the inhibitory effect of zinc on Fe2+-initiated lipid oxidation. The interaction of zinc with the bilayer did not affect physical properties of the membrane, including rigidification and lateral phase separation known to increase lipid oxidation rates. The interactions between zinc and the lipid- ([alpha]-tocopherol) and water- (epicatechin) soluble antioxidants were studied. The inhibition of Fe2+-induced lipid oxidation by either [alpha]-tocopherol or epicatechin was increased by the simultaneous addition of zinc. The combined actions of [alpha]-tocopherol (0.01 mol%), epicatechin (0.5 [mu]M) and zinc (5-50 [mu]M) almost completely prevented Fe2+ (25 [mu]M)-initiated lipid oxidation. These results show that zinc can protect membranes from iron-initiated lipid oxidation by occupying negatively charged sites with potential iron binding capacity. In addition, the synergistic actions of zinc with lipid and water-soluble antioxidants to prevent lipid oxidation, suggests that zinc is a pivotal component of the antioxidant defense network that protects membranes from oxidation. Zinc/ Free radicals/ Lipid oxidation/ Epicatechin/ [alpha]-Tocopherol/ Antioxidants

Zaroogian, G., Heltshe, J. F., and Johnson, M. (1985). Estimation of Toxicity to Marine Species with Structure-Activity Models Developed to Estimate Toxicity to Freshwater Fish. Aquat.Toxicol. 6: 251-270.
Chem Codes: Chemical of Concern: DZ Rejection Code: REFS CHECKED/REVIEW.

Zaroogian, G. E., Heltshe, J. F., and Johnson, M. (1985). Estimation of Bioconcentration in Marine Species Using Structure-Activity Models. Environ.Toxicol.Chem. 4: 3-12.

Chem Codes: EcoReference No.: 14368
Chemical of Concern: DZ Rejection Code: MODELING/QSAR/REFS CHECKED/REVIEW.

Zeigler, M., Zlotogora, J., Regev, R., Dagan, A., Gatt, S., and Bach, G. (1984). Prenatal diagnosis of krabbe disease using a fluorescent derivative of galactosylceramide. Clinica Chimica Acta 142: 313-318.

Chem Codes: Chemical of Concern: DZ Rejection Code: HUMAN HEALTH.

A fluorescent substrate 12-(N-methyl-N(7-nitro-2-oxa-1,3-diazol-4-yl) aminododecanoyl sphingosyl [beta]--galactoside (‘NBD galactocerebroside’) was synthesized and used for the detection of galactocerebrosidase activity. The enzyme determinations using this substrate were found to be extremely sensitive yielding unambiguous results. This substrate was used for the prenatal diagnosis of a fetus affected with Krabbe disease; the diagnosis was later confirmed in the aborted fetus. Krabbe disease/ Galactocerebrosidase/ Prenatal diagnosis

Zellmer, S., Cevc, G., and Risse, P. (1994). Temperature- and pH-controlled fusion between complex lipid membranes. Examples with the diacylphosphatidylcholine/fatty acid mixed liposomes. Biochimica et Biophysica Acta (BBA) - Biomembranes 1196: 101-113.
Chem Codes: Chemical of Concern: DZ Rejection Code: METHODS.

The fusion capability of complex lipid bilayers and its pH as well as temperature sensitivity have been studied by optical and spectroscopic means. The aggregation and fusion efficiency of such lipid membranes can be optimized by controlling the phase characteristics of the individual membrane components. For a practically relevant illustration, the stoichiometric 1:2 (mol/mol) mixtures of phosphatidylcholines and fatty acids are used. Perhaps the most interesting liposomes of this kind, which are made of dipalmitoylphosphatidylcholine/elaidic acid (DPPC/ELA-COOH (1:2)), undergo a chain-melting phase transition between 42[deg]C and 48[deg]C, depending on the bulk pH value. The highest chain-melting phase transition temperatures are measured with the fully protonated fatty acids at pH - mixed vesicles decreases. The fusion efficacy of the PC/FA(-) mixed liposomes at pH >= pK(FA) [approximate] 7.5 is practically negligible. This is largely due to the increased interbilayer repulsion and to the relatively high water-solubility of the deprotonated fatty acid molecules at high pH. While the pH-variability chiefly affects the efficacy of the intermembrane aggregation, the vesicle fusion itself is more sensitive to temperature variations. It is most likely that the temperature dependence of the intramembrane defect density is chiefly responsible for this. Optimal conditions for the fusion between DPPC/ELA-COOH (1:2) mixed vesicles are thus 3.5 T >= 41.5[deg]C = Tm(DPPC) (defect density and fusion maximum). Under such conditions the average size of PC/FA (1:2) mixed vesicles in a 1 mM suspension increases by a factor of 10 over a period of 10 min. Interbilayer fusion can also be catalyzed by the mechanically induced local membrane defects. Freshly made liposomes thus always fuse more avidly than aged vesicles. This permits estimates of the kinetics of membrane defects annihilation based on the measured temporal dependence of the maximum fusion-rate. From such studies, a quasi-exponential decay on the time scale of 1.2 h is found for the thermolabile fusogenic DPPC/ELA-COOH liposomes. Lipid vesicle/ Phase behavior/ Membrane fusion/ Phosphatidylcholine/ Fatty acid/ Drug carrier/ Mixed bilayer