Geometry of the dry-state oligomerization of 2′,3′-cyclic phosphates

Summary Evaporation of a solution of thymidine plus either theexo or theendo diastereomer of uridine cyclic 2,3-O, O-phosphorothioate (U > p(S) in 1,2-diaminoethane hydrochloride buffer gave the 2,5 and 3,5 isomers of (P-thio) uridylylthymidine (Up(S)dT) in a ratio of 1:2 with a combined yield of about 20%. These isomers were re-converted to U > p(S) and dT by a reaction that is known to proceed by an in-line mechanism. Both the 2,5 and 3,5 isomers gave as product the same diastereomer of U > p(S) that had been used originally in their formation. These dry-state prebiotic reactions (Verlander, Lohrmann, and Orgel 1973) are thus shown to be stereospecific, and both the 2,5 and 3,5 internucleotide bonds are formed by an in-line mechanism.Abbreviations DAE 1,2-diaminoethane - HPLC high pressure liquid chromatography - RNase bovine pancreatic ribonuclease A, EC 3.1.4.22 - TEAB triethylammonium bicarbonate - tris tris(hydroxymethyl)aminomethane - UMP(S) uridine monophosphorothioate - U > p uridine cyclic 2,3-phosphate - U > p(S) uridine cyclic 2,3-O, O-phosphorothioate - Up(S)dT (P-thio)uridylylthymidine - U2p(R_p-S)5dT (P-thio)uridylylthymidine with theR configuration at phosphorous, and a 2,5 internucleotide linkage     

Kinetics of growth and lactic acid production in continuous and batch culture

Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara     

On morphological variation in Keratella cochlearis populations from Holstein lakes (Northern Germany)

Keratella cochlearis occurs in many Holstein lakes (northern Germany) as three well defined and separated forms: cochlearis, hispida, and tecta, each showing very little variation between the lakes. The present data show that the tecta form did not originate from a Lauterborn cycle.     

Diallel analysis of submergence tolerance in rice,Oryza sativa L.

Summary The genetics of submergence tolerance in rice was studied in a 10 × 10 half-diallel cross set involving 10 lowland rice varieties, four of which were tolerant (FR13A, FR43B, Kurkaruppan, and Goda Heenati) and the remaining six were nontolerant (RD19, IR42, IR17494-32-1, IR19672-24-3, Jagannath, and CR1009). Estimates of genetic parameters following Hayman's method showed significant additive and nonadditive gene action and the latter appeared to be solely due to dominance. Narrow sense heritability (0.70) indicated that additive gene effects were more important in the inheritance of the trait. Tolerance was dominant over nontolerance and the average dominance was within the range of incomplete dominance. Dominant alleles were more concentrated in the three tolerant parents, FR13A, Kurkaruppan, and FR43B in that order. Wr/Vr graphic analysis suggested the involvement of both major and minor genes. Combining ability analysis by Griffing's method also indicated significance of both additive and nonadditive effects, and the former appeared to be more important than the latter. The hybrids involving FR13A with RD19, IR42, and IR17494-32-1, and those of Kurkaruppan with RD19 and CR1009 appeared to be promising for incorporating an adequate level of tolerance to submergence into lowland rice cultivars.     

Endosperm-specific demethylation and activation of specific alleles of α-tubulin genes of Zea mays L.

We have investigated the methylation status of the -tubulin genes, and the degree of accumulation of their mRNAs in endosperm, embryo and seedling tissues of Zea mays L. We have found that many of the -tubulin genes are differentially demethylated in the endosperm relative to the embryo and seedling. However, only for tub2 and tub4 could a correlation between DNA demethylation and increased RNA accumulation be detected. By analyzing the inbred lines W64A and A69Y and their reciprocal crosses, we have also identified in the endosperm two -tubulin genes, tub3 and tub4, that are differentially demethylated if transmitted by the maternal germline, but that remain hypermethylated when transmitted by the paternal germline.     

Synthesis of Aminoethyl Glycosides of the Ganglioside GM1 and Asialo-GM1 Oligosaccharide Chains

4-O-Glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)--D-glucopyranoside with a disaccharide donor, 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-1-thio-2-trichloroacetamido--D-galactopyranoside, in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in a tetrasaccharide, 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, in 69% yield. The complete removal of O-protecting groups in the tetrasaccharide, the replacement of N-trichloroacetyl by N-acetyl group, and the reduction of the aglycone azide group to amine led to the target aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)--D-Gal-(1 4)--D-Glc-OCH₂CH₂NH₂ containing the oligosaccharide chain of asialo-GM₁ ganglioside in 72% overall yield. Selective 3-O-glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,6-di-O-benzyl--D-galactopyranosyl)--D-glucopyranoside with thioglycoside methyl (ethyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero--D-galacto-2-nonulopyranosyl)oate in acetonitrile in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid afforded 2-azidoethyl [methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)oate]-(2 3)-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, the selectively protected derivative of the oligosaccharide chain of GM₃ ganglioside, in 79% yield. Its 4-O-glycosylation with a disaccharide glycosyl donor, (4-trichloroacetophenyl-4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl) 1-thio-2-trichloroacetamido--D-galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid gave 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-{[methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)onate]-(2 3)}-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside in 85% yield. The resulting pentasaccharide was O-deprotected, its N-trichloroacetyl group was replaced by N-acetyl group, and the aglycone azide group was reduced to afford in 85% overall yield aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)-[-D-Neu5Ac-(2 3)]--D-Gal-(1 4)--D-Glc-OCH₂CH₂NH₂ containing the oligosaccharide chain of GM₁ ganglioside.     

A model of associative memory in the brain

A model of associative memory for time varying spatial patterns is proposed and simulated on a digital computer. This is a network composed of many neuron-like elements, and shows an ability for associative memory similar to that of the brain.Suppose a number of sequences of spatial patterns are presented to this network, for example, 12345, ABC, and so on. Then, these patterns are memorized in the network. After that, if any part of one of these sequences, say 23, is presented to the circuit, the rest of the sequence, 45, is recalled following to it. It resembles to such a situation — if we hear a part of a melody which we have memorized in the past, the rest of the melody is recalled even after it is stopped half-way. Although the recalled patterns are not always 100% correct, they are not completely destroyed even if the presented patterns are imperfect.     

On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.     

Genotypic control of pollen plant formation in Nicotiana tabacum L.

Summary Tobacco plants (Nicotiana tabacum L.) of four varieties (Badischer Burley, White Burley, Techne, Kupchunos) were raised at different temperatures and daylengths and the effect of genotype on embryogenic pollen grain formation in situ and on pollen plant formation in anther and pollen cultures from these plants was studied. Genotype controlled embryogenic pollen grain and pollen plant formation by defining productivity under standard growth conditions (long days at 24 °C). Kupchunos was the most productive variety, followed by White Burley, Techne, and Badischer Burley. Furthermore, genotype defined which environmental factor was able to affect embryogenic pollen grain and pollen plant formation and also to which degree. In anther cultures, in addition to these effects, genotype controlled the formation of (an) inhibitory substance(s) in the anther wall in interaction with the plant growth conditions. In Badischer Burley and Techne, inhibitor action could be prevented by isolation of the pollen after one week of anther culture. Finally, direct pollen cultures in Badischer Burley and Techne produced embryos were only when the pollen was isolated from nearly mature anthers, while in White Burley and Kupchunos, embryos also produced at earlier stages and at higher yields. This indicated that genotype controls the time when the embryogenic pollen grains become ready to divide. The results are discussed in relation to strategies to overcome recalcitrance of species and genotypes.     

An efficient cryopreservation procedure for potato (Solanum tuberosum L.) utilizing the new ice blocking agent, Supercool X1000

Cryopreservation has been recognized as a practical and efficient tool for long-term storage of vegetatively propagated plants. This study was conducted to investigate effects of modified vitrification techniques on cryopreservation of potato. In vitro plants of potato cultivars Superior and Atlantic were cold acclimated, and axillary buds were precultured, osmoprotected, exposed to PVS-2 solution, plunged into liquid nitrogen, thawed, and finally planted in the regeneration medium. In the modified vitrification technique an ice-blocking agent, Supercool X1000, was added with PVS-2 solution. Cold acclimation affected survival of cryopreserved shoot tips, and the highest survival (46.7%) was obtained after 3 weeks of acclimation at 10°C. Shoot tips exposed to 2M glycerol plus 0.6M sucrose for 40 min gave 51.5% and 11.7% survival in Atlantic and Superior at 10°C, respectively. Cold acclimated and osmoprotected shoot tips were dehydrated with PVS-2 containing different concentrations of Supercool X1000 prior to a plunge into liquid nitrogen. Treatments with 0.1% and 1% of Supercool X1000 significantly improved survival by 55% in Superior and 71.3% in Atlantic, respectively. After cryopreservation, vitrified shoot tips resumed growth within a week in a medium (1 mg l^–1 GA₃, 0.5 mg l^–1 zeatin, and 0.1 mg l^–1 IAA) with a low level of Pluronic F-68 (0.005%) and survival was 33.7% higher in Atlantic and 14.7% higher in Superior than the control (without Pluronic F-68).     

Photoperiodic induction of the first and the second diapause in the bean bug,Riptortus clavatus: a photoperiodic history effect

Summary In nondiapause adults raised under a long-day photoperiod, the critical daylength for diapause induction was between 13 and 14 h although some individuals did not respond to the short-day photoperiod and went on laying eggs. In postdiapause adults in which LD 1311 induced the first diapause (L13 insects), the critical daylength for diapause reinduction was between 13 and 14 h, whereas it was between 12 and 13 h in postdiapause adults in which LD 1014 induced the first diapause (L10 insects). Under LD 1311, a small proportion of L10 insects went into the second diapause after great delay as compared with L13 insects. Under LD 1014, on the other hand, L10 insects went into the second diapause more rapidly than L13 insects. Therefore, the photoperiod which had induced the first diapause affected the photoperiodic induction of the second diapause not only in the critical daylength but also in the speed of response. In Riptortus clavatus, the photoperiodic history influences the subsequent photoperiodic response even after a physiological state induced by the previous photoperiod was terminated completely.Abbreviations L13 insects postdiapause adults in which LD 1311 induced the first diapause - L10 insects postdiapause adults in which LD 1014 induced the first diapause     

The catalysis of nucleotide polymerization by compounds of divalent lead

Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A adenosine - U uridine - Im imidazole - MeIm 1-methyl-imidazole - EDTA ethylenediaminetetraacetic acid - pA adenosine 5-phosphate - pU uridine 5-phosphate - Ap adenosine cyclic 2:3-phosphate - ATP adenosine 5-triphosphate - AppA P₁,P₂-diadenosine 5-diphosphate - pNp (N = A,U) nucleotide 2(3), 5-diphosphate - ImpA adenosine 5-phosphoreimidazolide - ImpU uridine 5-phosphorimidazolide - A ²pA adenylyl-[25]-adenosine - A ³pA adenylyl-[35]-adenosine - pA ²pA 5-phospho-adenylyl-[25]-adenosine - pA ³pA 5-phospho-adenylyl-[35]-adenosine - pUpU 5-phospho-uridylyl-uridine - pApU 5-phospho-adenylyl-uridine - pUpA 5-phospho-uridylyladenine - (pA)n (n, 2,3,4,) oligoadenylates with 5 terminal phosphate - ImpApA 5-phosphorimidazolide of adenylyl adenosine - (pA) ₅₊ pentamer and higher oligoadenylates with 5 terminal phosphate - (Ap)nA (n = 2,3,4) oligoadenylates without terminal phosphates In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage     

Viability and activity in readily culturable bacteria: a review and discussion of the practical issues

In microbiology the terms viability and culturability are often equated. However, in recent years the apparently self-contradictory expression viable-but-nonculturable (VBNC) has been applied to cells with various and often poorly defined physiological attributes but which, nonetheless, could not be cultured by methods normally appropriate to the organism concerned. These attributes include apparent cell integrity, the possession of some form of measurable cellular activity and the apparent capacity to regain culturability. We review the evidence relating to putative VBNC cells and stress our view that most of the reports claiming a return to culturability have failed to exclude the regrowth of a limited number of cells which had never lost culturability. We argue that failure to differentiate clearly between use of the terms viability and culturability in an operational versus a conceptual sense is fuelling the current debate, and conclude with a number of proposals that are designed to help clarify the major issues involved. In particular, we suggest an alternative operational terminology that replaces VBNC with expressions that are internally consistent.     

Negative-ion fast atom bombardment tandem mass spectrometry for characterization of sulfated unsaturated disaccharides from heparin and heparan sulfate

Negative-ion fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from heparin and heparan sulfate. The positional isomers of the sulfate group of monosulfated disaccharides were distinguished from each other by negative-ion fast atom bombardment tandem mass spectra, which provide an easy way of identifying the positional isomers. This fast atom bombardment collision induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of di- and trisulfated disaccharides.Abbreviations FABMS fast atom bombardment mass spectrometry - CID collision induced dissociation - MIKE mass analysed ion kinetic energy - MS/MS mass spectrometry/mass spectrometry - HPLC high performance liquid chromatography - UA d-gluco-4-enepyranosyluronic acid - CS chondroitin sulfate - DS dermatan sulfate - HA hyaluronan - Hep heparin - HS heparan sulfate - UA(14) GlcNAc 2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose - UA(14)GlcNAc6S 2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA2S(14)GlcNAc 2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose - UA2S(14)GlcNAc6S 2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA(14)GlcN6S 2-amino-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA2S(14)GlcN 2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose - UA2S(14)GlcN6S 2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA(14)GlcNS 2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose - UA(14)GlcNS6S 2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA2S(14)GlcNS 2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose - UA2S(14)GlcNS6S 2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose - UA(13)GalNAc 2-acetamido-2-deoxy-3-O-(-d-Gluco-4-enepyranosyluronic acid)-d-galatose - UA(13)GalNAc4S 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose - UA(13)GalNAc6S 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose - UA2S(13)GalNAc 2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-galactose - UA2S(13)GalNAc4S 2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose - UA2S(13)GalNAc6S 2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose - UA(13)GalNAcDiS 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4,6-di-O-sulfo-d-galactose - UA(13)GlcNAc 2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose.     

Effect of giving insulin and adrenalin alternately on changes in the level of blood glucose in chickens of different breeds

Summary Differences in reaction to exogenous insulin and adrenalin were studied among chickens of Leghorn, White Rock and Rhode Island Red breeds, using level of blood glucose as indicator of the reaction to hormones. It was found that: 1.) The physiological quantity of glucose in blood in chickens of the three breeds ranged from 157 to 194 mg %. 2.) The reaction of chickens to insulin and adrenalin given alternately, measured by changes of blood glucose, differed according to the breed. The smallest reaction to hormones was in Leghorn, the biggest in White Rock. 3.) The chickens of Leghorn and Rhode Island Red breeds, as well as Leghorn and White Rock breeds, differed significantly in maximal glucose level after adrenalin, 4.) The correlation between the normal quantity of blood glucose and the body weight of birds appeared highly significant in cockerels of all three races combined.     

Purification and partial characterisation of and α-tocopherol-binding protein from rabbit heart cytosol

An -tocopherol-binding protein has been isolated and purified from rabbit heart cytosol. The purified protein had an apparent molecular mass of 14,200, as derived from SDS-PAGE. The content of the protein in rabbit heart was around 11.8 g per g of tissue. The binding of -tocopherol to the purified protein was rapid, reversible, and saturable. Neither nor tocopherol could displace the bound -tocopherol from the protein, suggesting a high specificity for -tocopherol. -Tocopherol-binding protein did not bind oleate. Transfer of -tocopherol from liposomes to mitochodria was stimulated 8-fold in the presence of the binding protein, suggesting that this protein may be involved in the intracellular transport of -tocopherol in the heart.     

Mass spectrometric analysis of genetic and post-translational heterogeneity in the lectins Jacalin andMaclura pomifera agglutinin

Jacalin andM. pomifera agglutinin are T-antigen specific lectins with ₄₄ structures that show far greater microheterogeneity than plant lectins from other families, due to multiple genetic isoforms and post-translational processing. Electrospray mass spectrometry and combined liquid chromatography-electrospray mass spectrometry were used to characterize the various forms. For both lectins, the mass data were consistent with previous protein sequencing of the major -chain species of 133 residues and three -chain species of 20 or 21 residues. In addition, for jacalin the mass of one minor -chain species was consistent with a second of the four reported gene sequences. However, the glycopeptide -chain form and one -chain form did not match any of the genes, suggesting a fifth gene remains to be found. ForM. pomifera agglutinin, three more -chain forms were found, but all six could arise from only two genes, with additional post-translational proteolysis and post-translational substitution with an unidentified component of 106 Da creating the set of six forms. Only two -chain forms were found also, with no glycosylation.     

Carbon isotope composition in relation to leaf gas exchange and environmental conditions in Hawaiian Metrosideros polymorpha populations

Summary Carbon isotope composition, photosynthetic gas exchange, and nitrogen content were measured in leaves of three varieties of Metrosideros polymorpha growing in sites presenting a variety of precipitation, temperature and edaphic regimes. The eight populations studied could be divided into two groups on the basis of their mean foliar ¹³C values, one group consisting of three populations with mean ¹³C values ca.-26 and another group with ¹³C values ca.-28. Less negative ¹³C values appeared to be associated with reduced physiological availability of soil moisture resulting from hypoxic conditions at a poorly drained high elevation bog site and from low precipitation at a welldrained, low elevation leeward site. Gas exchange measurements indicated that foliar ¹³C and intrinsic wateruse efficiency were positively correlated. Maximum photosynthetic rates were nearly constant while maximum stomatal conductance varied substantially in individuals with foliar ¹³C ranging from-29 to-24. In contrast with the patterns of ¹³C observed, leaf nitrogen content appeared to be genetically determined and independent of site characteristics. Photosynthetic nitrogenuse efficiency was nearly constant over the range of ¹³C observed, suggesting that a compromise between intrinsic water- and N-use efficiency did not occur. In one population variations in foliar ¹³C and gas exchange with leaf cohort age, caused the ratio of intercellular to atmospheric partial pressure of CO₂ predicted from gas exchange and that calculated from ¹³C to be in close agreement only in the two youngest cohorts of fully expanded leaves. The results indicated that with suitable precautions concerning measurement protocol, foliar ¹³C and gas exchange measurements were reliable indicators of potential resource use efficiency by M. polymorpha along environmental gradients.     

Evaluation of hydrophobicity versus chaperonelike activity of bovine alphaA- and alphaB-crystallin

Calf lens A-crystallin isolated by reversed-phase HPLC demonstrates a slightly more hydrophobic profile than B-crystallin. Fluorescent probes in addition to bis-ANS, like cis-parinaric acid (PA) and pyrene, show higher quantum yields or Ham ratios when bound to A-crystallin than to B-crystallin at room temperature. Bis-ANS binding to both A- and B-crystallin decreases with increase in temperature. At room temperature, the chaperone-like activity of A-crystallin is lower than that of B-crystallin whereas at higher temperatures, A-crystallin shows significantly higher protection against aggregation of substrate proteins compared to B-crystallin. Therefore, calf lens A-crystallin is more hydrophobic than B-crystallin and chaperone-like activity of -crystallin subunits is not quantitatively related to their hydrophobicity.