Theoretical description of hydrogen bonding in oxalic acid dimer and trimer based on the combined extended-transition-state energy decomposition analysis and natural orbitals for chemical valence (ETS-NOCV)

In the present study we have analyzed hydrogen bonding in dimer and trimer of oxalic acid, based on a recently proposed charge and energy decomposition scheme (ETS-NOCV). In the case of a dimer, two conformations, α and β, were considered. The deformation density contributions originating from NOCV’s revealed that the formation of hydrogen bonding is associated with the electronic charge deformation in both the σ—(Δρ_σ) and π-networks (Δρ_π). It was demonstrated that σ-donation is realized by electron transfer from the lone pair of oxygen on one monomer into the empty r_{H - O}^* \rho_{H - O}^* orbital of the second oxalic acid fragment. In addition, a covalent contribution is observed by the density transfer from hydrogen of H-O group in one oxalic acid monomer to the oxygen atom of the second fragment. The resonance assisted component (Δρ_π), is based on the transfer of electron density from the π—orbital localized on the oxygen of OH on one oxalic acid monomer to the oxygen atom of the other fragment. ETS-NOCV allowed to conclude that the σ(O---HO) component is roughly eight times as important as π (RAHB) contribution in terms of energetic estimation. The electrostatic factor (ΔE_elstat) is equally as important as orbital interaction term (ΔE_orb). Finally, comparing β-dimer of oxalic acid with trimer we found practically no difference concerning each of the O---HO bonds, neither qualitative nor quantitative.     

Mechanistic insight from thermal activation parameters for oxygenation reactions of different substrates with biomimetic iron porphyrin models for compounds I and II

Compound I, an oxo–iron(IV) porphyrin π-cation radical species, and its one-electron-reduced form compound II are regarded as key intermediates in reactions catalyzed by cytochrome P450. Although both reactive intermediates can be easily produced from model systems such as iron(III) meso-tetra(2,4,6-trimethylphenyl)porphyrin hydroxide by selecting appropriate reaction conditions, there are only a few thermal activation parameters reported for the reactions of compound I analogues, whereas such parameters for the reactions of compound II analogues have not been investigated so far. Our study demonstrates that ΔH ^≠ and ΔS ^≠ are closely related to the chemical nature of the substrate and the reactive intermediate (viz., compounds I and II) in epoxidation and C–H abstraction reactions. Although most studied reactions appear to be enthalpy-controlled (i.e., ΔH ^≠ > −TΔS ^≠), different results were found for C–H abstractions catalyzed by compound I. Whereas the reaction with 9,10-dihydroanthracene as a substrate is also dominated by the activation enthalpy (ΔH ^≠ = 42 kJ/mol, ΔS ^≠ = 41 J/Kmol), the same reaction with xanthene shows a large contribution from the activation entropy (ΔH ^≠ = 24 kJ/mol, ΔS ^≠ = −100 J/kmol). This is of special interest since the activation barrier for entropy-controlled reactions shows a significant dependence on temperature, which can have an important impact on the relative reaction rates. As a consequence, a close correlation between bond strength and reaction rate—as commonly assumed for C–H abstraction reactions—no longer exists. In this way, this study can contribute to a proper evaluation of experimental and computational data, and to a deeper understanding of mechanistic aspects that account for differences in the reactivity of compounds I and II.     

A possible crystal volume factor in the impact sensitivities of some energetic compounds

We have investigated the possibility of a link between the impact sensitivities of energetic compounds and the space available to their molecules in their crystal lattices. As a measure of this space, we use ΔV=V_eff−V(0.002), where V_eff is the effective molecular volume obtained from the crystal density and V(0.002) is that enclosed by the 0.002 au contour of the molecule’s gas phase electronic density, determined computationally. When experimental impact sensitivity was plotted against ΔV for a series of 20 compounds, the nitramines formed a separate group showing little dependence upon ΔV. Their impact sensitivities correlate well with an anomalous imbalance in the electrostatic potentials on their molecular surfaces, which is characteristic of energetic compounds in general. The imbalance is symptomatic of the weakness of the N–NO₂ bonds, caused by depletion of electronic charge. The impact sensitivities of non-nitramines, on the other hand, depend much more strongly upon ΔV, and can be quite effectively related to it if an electrostatically-based correction term is included.     

Mechanosensitive ion channels in chara: influence of water channel inhibitors, HgCl2 and ZnCl2, on generation of receptor potential

Characean internodal cells generate receptor potential (ΔE _m) in response to mechanical stimuli. Upon a long-lasting stimulus, the cells generated ΔE _m at the moment of both compression and decompression, and the amplitude of ΔE _m at the moment of decompression, (ΔE _m)_E, was larger than that at compression. The long-lasting stimulus caused a membrane deformation (ΔD _m) having two components, a rapid one, (ΔD _m)_rapid, at the moment of compression and a slower one, (ΔD _m)_slow, during the long-lasting compression. We assumed that (ΔD _m)_slow might have some causal relation with the larger ΔE _m at (ΔE _m)_E. We treated internodal cells with either HgCl₂ or ZnCl₂, water channel inhibitors, to decrease (ΔD _m)_slow. Both inhibitors attenuated (ΔD _m)_slow during compression. Cells treated with HgCl₂ generated smaller (ΔE _m)_E compared to nontreated cells. On the other hand, cells treated with ZnCl₂ never attenuated (ΔE _m)_E but, rather, amplified it. Thus, the amplitude of (ΔD _m)_slow did not always show tight correlation with the amplitude of (ΔE _m)_E. Furthermore, when a constant deformation was applied to an internodal cell in a medium with higher or lower osmotic value, a cell having higher turgor always showed a larger (ΔE _m)_E. Thus, we concluded that changes in tension at the membrane may be the most important factor to induce activation of mechanosensitive Ca²⁺ channel.     

Quasi steady state growth of <Emphasis Type="Italic">Lactococcus lactis</Emphasis> in glucose-limited acceleration stat (A-stat) cultures

Quasi steady state growth of Lactococcus lactis IL 1403 was studied in glucose-limited A-stat cultivation experiments with acceleration rates (a) from 0.003 to 0.06 h⁻² after initial stabilization of the cultures in chemostat at D = 0.2–0.3 h⁻¹. It was shown that the high limit of quasi steady state growth rate depended on the acceleration rate used—at an acceleration rate 0.003 h⁻² the quasi steady state growth was observed until μ _crit = 0.59 h⁻¹, which is also the μ _max value for the culture. Lower values of μ _crit were observed at higher acceleration rates. The steady state growth of bacteria stabilized at dilution rate 0.2 h⁻¹ was immediately disrupted after initiating acceleration at the highest acceleration rate studied—0.06 h⁻². Observation was made that differences [Δ(μ − D)] of the specific growth rates from pre-programmed dilution rates were the lowest using an acceleration rate of 0.003 h⁻² (< 4% of preset changing growth rate). The adaptability of cells to follow preprogrammed growth rate was found to decrease with increasing dilution rate—it was shown that lower acceleration rates should be applied at higher growth rates to maintain the culture in the quasi steady state. The critical specific growth rate and the biomass yields based on glucose consumption were higher if the medium contained S ₀ = 5 g L⁻¹ glucose instead of S ₀ = 10 g L⁻¹. It was assumed that this was due to the inhibitory effect of lactate accumulating at higher concentrations in the latter cultures. Parallel A-stat experiments at the same acceleration and dilution rates showed good reproducibility—Δ(μ − D) was less than 5%, standard deviations of biomass yields per ATP produced (Y _ATP), and biomass yields per glucose consumed (Y _XS) were less than 15%.     

Truncation Mutants Highlight a Critical Role for the N- and C-termini of the Spirulina Δ6 Desaturase in Determining Regioselectivity

The results of our previous study on heterologous expression in Escherichia coli of the gene desD, which encodes Spirulina Δ⁶ desaturase, showed that co-expression with an immediate electron donor—either cytochrome b ₅ or ferredoxin—was required for the production of GLA (γ-linolenic acid), the product of the reaction catalyzed by Δ⁶ desaturase. Since a system for stable transformation of Spirulina is not available, studies concerning Spirulina-enzyme characterization have been carried out in heterologous hosts. In this present study, the focus is on the role of the enzyme’s N- and C-termini, which are possibly located in the cytoplasmic phase. Truncated enzymes were expressed in E. coli by employing the pTrcHisA expression system. The truncation of the N- and C-terminus by 10 (N10 and C10) and 30 (N30 and C30) amino acids, respectively, altered the enzyme’s regioselective mode from one that measures from a preexisting double bond to that measuring from the methyl end of the substrate.     

Gamma-irradiated plant callus tissue: Cytokinins from transfer ribonucleic acid

Summary Callus tissue ofHaworthia mirabilis Haw. was irradiated with⁶⁰Co gamma rays. tRNA was isolated, hydrolyzed enzymatically, and cytokinin-active ribonucleosides were separated by Sephadex LH-20 column chromatography and assayed with the tobaccocallus cytokinin bioassay. Three cytokinins were detected in tRNA from irradiated tissue, two of which chromatographed with zeatin riboside and N⁶-(Δ²-isopentenyl)adenosine. The third cytokinin-active ribonucleoside was retained longer than the above compounds on the Sephadex column and may be 2-methylthio-N⁶-(Δ²-isopentenyl)adenosine. Two cytokinins were detected in tRNA from nonirradiated tissue—those chromatographed with zeatin riboside and N⁶-(Δ²-isopentenyl)adenosine. Relationships between cytokinins from tRNA and free cytokinins found in tissue earlier are discussed. This is paper 78-10-124 of the Kentucky Agricultural Experiment Staton and is published with approval of the Director.     

Respiratory and metabolic responses of the Australian Yabby Cherax destructor to progressive and sustained environmental hypoxia

The Australian Yabby, Cherax destructor, inhabits occasionally hypoxic water. The respiratory gas, acid-base, metabolite and energetic status of this crayfish was assessed during progressive hypoxia and during 3 h at a water PO₂ of 1.33 kPa. The O₂ affinity of haemocyanin from C. destructor was increased by lactate (Δlog P ₅₀/Δlog[lactate] = −0.111) and by Ca (Δlog P ₅₀/Δlog[Ca] = −0.62) but not by urate. While the non-bicarbonate buffering capacity was low (Δ[HCO₃ ⁻]/ ΔpH=−4.89) the haemocyanin had a low sensitivity to pH changes (ϕ = −0.33). The crayfish showed a compensatory hyperventilation, which induced a respiratory alkalosis, until the water O₂ partial pressure declined below 2.67 kPa, after which the O₂ uptake rate was approximately 10% of normoxic rates. The high haemocyanin-O₂ affinity maintained haemolymph O₂ content during progressive hypoxia despite the normally low arterial O₂ partial pressure of C. destructor. During severe hypoxia, pH decreased but increased lactate aided in maintaining haemocyanin-O₂ saturation. The importance of regulated haemocyanin-O₂ affinity in hypoxic C. destructor was reduced by lowered metabolism, including reduced cardiac output, and the consequent reduction in O₂ requirement. Anaerobiosis became important only at very low PO₂ but thereafter proceeded rapidly, supported by a marked hyperglycaemia. There was no depletion of adenylates, even after 3 h of severe hypoxia. The tail muscle of C. destructor held small amounts of glycogen which would sustain anaerobiosis for a only a few hours. Hypometabolism seems an important hypoxic response but severe hypoxia may encourage the crayfish to breathe air. Accepted: 26 February 1998     

Formate Hydrogenlyase Is Needed for Proton-Potassium Exchange Through the F0F1-ATPase and the TrkA System in Anaerobically Grown and Glycolysing Escherichia coli

Anaerobically grown and glycolysing Escherichia coli produced H₂ and carried out H⁺-K⁺-exchange in two steps, the first of which had the fixed stoichiometry for DCCD-sensitive fluxes (2H⁺/K⁺), and the second one had a variable stoichiometry for DCCD-sensitive fluxes. H₂ production and the 2H⁺/K⁺-exchange were lost in the ΔfdhF or ΔhycA-H mutant. In the ΔfdhF mutant, H⁺-K⁺-exchange with K _m for K⁺-uptake of 2.3 mM and less K⁺-gradient between the cytoplasm and the medium were observed. H₂ production and H⁺-K⁺-exchange with a high K _m for K⁺-uptake were carried out in the uncD mutant; however, both H₂ production and H⁺-K⁺-exchange were lost in the Δunc or uncE mutant. H₂ production was observed in the trkA trkD kdpA mutant. It was displayed in protoplasts with increased membrane permeability when donor or acceptor of reducing equivalents—formate with DTT or NADH respectively—was added. The F₀F₁ and the TrkA(H) or the F₀ and the TrkA(G) had been assumed to form the united supercomplexes, functioning as a H⁺-K⁺-pump or antiporter respectively (for review see Bioelectrochem Bioenerg 33:1, 1994). Results allow the proposal that H₂ production by FHL has a relationship with the H⁺-K⁺-exchange through a H⁺-K⁺-pump and via an H⁺-K⁺-antiporter. Formate and NADH can serve as a donor and an acceptor of reducing equivalent respectively, for operation of such supercomplexes. Received: 12 December 1996 / Accepted: 19 March 1997     

Isolation and functional characterization of polyunsaturated fatty acid elongase (AsELOVL5) gene from black seabream (Acanthopagrus schlegelii)

To identify the genes encoding fatty acid elongases for the biosynthesis of polyunsaturated fatty acids (PUFAs), we isolated a cDNA via degenerate PCR and RACE-PCR from Acanthopagrus schlegelii with a high similarity to the ELOVL5-like elongases of mammals and fishes. This gene is termed AsELOVL5 and encodes a 294 amino acid protein. When AsELOVL5 was expressed in Saccharomyces cerevisiae, it conferred an ability to elongate γ-linolenic acid (18:3 n−6) to di-homo-γ-linolenic acid (20:3 n−6). In addition, the transformed cells converted arachidonic acid (20:4 n−6) and eicosapentaenpic acid (20:5 n−3) to docosatetraenoic acid (22:4 n−6) and docosapentaenoic acid (22:5 n−3), respectively. These results indicate that the AsELOVL5 gene encodes a long-chain fatty acid elongase capable of elongating C₁₈Δ6/C₂₀Δ5 but not C₂₂ PUFA substrates.     

The application of sterol biomarkers to the study of the sources of particulate organic matter in the Solo River system and and Serayu River,Java, Indonesia

Sterols were analyzed in suspended particles collected in January 1991 in the Solo River system and in the Serayu River, Java, Indonesia. Free sterols were extracted from particles larger than 0.7 μm and analyzed, after derivatization into their trimethylsilyl esters, by GC and GC/MS. Concentrations of total sterols ranged from 438 to 7922 ng/1, or from 2.4 to 183.8 ng/mg of total suspended matter, which varied from 3.3 to 400 and 471 mg/l, respectively in the Serayu River and at the downstream station in the Solo River. POC concentrations also varied in a wide range, from 0.91 to 4.72 and 6.13% of TSM, respectively at the above stations, and were associated with sterol/POC values ranging from 0.15 to 1.75 μg/mg. Eleven structures of C₂₇, C₂₈ and C₂₉ sterols and associated stanols were identified. 28Δ^3,22 was only found at downstream stations in the Solo River and in the Serayu River. This unique distribution, different from that of other C₂₇, C₂₈ and C₂₉ sterols, suggests a predominantly autochthonous origin for these compounds associated with an increased planktonic biosynthesis near the estuary. Concentrations of 28Δ⁵, 29Δ^5,22 and 29Δ⁵ showed similar spatial distributions and increased downstream, reflecting the significant accumulation of organic matter originating from the vegetation of the various drainage basins. Values of the autochthonous versus terrigenous sterol index, defined as 27Δ⁵/29Δ^5,22 + 29Δ⁵ were in the 1.4–1.9 range at upstream stations, whereas at downstream stations lower values were found, 0.4–0.6, which also corresponded to higher concentrations of TSM and lower POC values. Insofar as the stanol/stenol values can be used to estimate the bacterial activity of oxic waters, simultaneous variations of C₂₇, and C₂₉ stenol/stanol pairs suggest rather different bacterial degradation capacities of autochthonous versus allochthonous organic matter. The wide differencies between the values of the stenol/stanol pairs observed in one of the main tributaries and in downstream stations of the Solo River is evidence that allochthonous organic matter is much more resistant than autochthonous matter. The low index value observed in the Serayu River indicates the highly refractory nature of both autochthonous and allochthonous organic material.     

Photosynthetic and stomatal responses of two tropical and two temperate trees to atmospheric humidity

The effects of leaf to air vapour pressure differences (ΔW) on net photosynthetic rate (P_N) and stomatal conductance (g_s) were examined in the leaves of two tropical rain forest trees, Eugenia grandis and Pongamia pinnata, and two temperate evergreen trees, Viburnum awabuki and Daphniphyllum macropodum. A single leaf was set inside a small chamber and ΔW was varied from 7 to 24 mmol mol^-1 at 25 and 500 μmol m^-2 s^-1 of photon flux density. P_N and g_s of the two tropical rain forest trees decreased with increasing ΔW, while the two temperate evergreen trees were not highly responsive to ΔW. P. pinnata was more sensitive to ΔW in its stomatal response, and had a higher stomatal density and higher stomatal index than did the two temperate trees and another tropical tree. Significant reductions i n g_s and intercellular CO₂ concentrations in the two tropical trees at high ΔW suggest that the decline of P_N was due to the decrease in g_s. The responses of P_N and g_s indicated that the tropical trees were more sensitive to ΔW than were the temperate ones. This revised version was published online in September 2006 with corrections to the Cover Date.     

Estimation of seasonal changes in translocation rates in leaves of a Japanese larch stand

To estimate the net rate of translocation in leaves of a larch stand, a new approach based on the summation method was proposed and given by a compartment model. The difference between the rate of translocation into and out of leaf biomass, namely, the net translocation rate (ΔT _r /Δt), was usually expressed by the difference between the growth rate of leaf biomass and the surplus production rate provided that the rate of leaf loss due to leaffall and grazing can be considered negligible. The rate, ΔT _r /Δt in a 19-yr-old larch stand, showed characteristic changes; it was positive from early April to late May, but after that it was negative until leaffall in late October. Our results confirmed that for the growth phase of positive ΔT _r /Δt translocation of assimilate stored in non-photosynthetic organs was indispensable for the growth. To quantify this, the ratio of ΔT _r /Δt to growth rate of leaf biomass was proposed.     

Computation of entropy contribution to protein-ligand binding free energy

The entropy contribution ΔS to protein-ligand binding free energy is studied for nine protein-lipid complexes. The entropy effect from the loss of the translational/rotational degrees of freedom (ΔS _tr) is calculated using the ideal gas approach. The change in the vibrational entropy (ΔS _vib) is calculated using the effective quantum oscillator approach with frequencies derived from the coordinate covariance matrix, so the inharmonic effects are taken into account. The change in the entropy of solvation (ΔS _solv) is considered using the binomial cell model (developed by the authors) for the hydrophobic effect. The entropy contribution from loss of conformations that are available for the free ligand (ΔS _conf) is also estimated. It is revealed that the negative in view of binding term ΔS _tr is only partly compensated by increasing of ΔS _vib, so T(ΔS _tr + ΔS _vib + ΔS _conf) < 0 for all complexes under investigation, but taking into account ΔS _solv leads to significantly increased ΔS. For all complexes except biotin-streptavidin, the results are found to be in reasonable agreement with experimental data. Published in Russian in Biokhimiya, 2007, Vol. 72, No. 7, pp. 963–973.     

Enhanced Solubility,Stability, and Transcorneal Permeability of Delta-8-Tetrahydrocannabinol in the Presence of Cyclodextrins

The purpose of this study was to investigate the effect of cyclodextrins (CDs) on aqueous solubility, stability, and in vitro corneal permeability of delta-8-tetrahydrocannabinol (Δ⁸-THC). Phase solubility of Δ⁸-THC was studied in the presence of 2-hydroxypropyl-β-cyclodextrin (HPβCD), randomly methylated-β-cyclodextrin (RMβCD) and sulfobutyl ether-β-cyclodextrin sodium salt (SβCD). Stability of Δ⁸-THC in 5% w/v aqueous CD solutions, as a function of pH, was studied following standard protocols. In vitro corneal permeation of Δ⁸-THC (with and without CDs) across excised rabbit cornea was also determined. Phase-solubility profile of Δ⁸-THC in the presence of both HPβCD and RMβCD was of the A_P type, whereas, with SβCD an A_L type was apparent. Aqueous solubility of Δ⁸-THC increased to 1.65, 2.4, and 0.64 mg/mL in the presence of 25% w/v HPβCD, RMβCD, and SβCD, respectively. Significant degradation of Δ⁸-THC was not observed within the study period at the pH values studied, except for at pH 1.2. Transcorneal permeation of Δ⁸-THC was dramatically improved in the presence of CDs. The results demonstrate that CDs significantly increase aqueous solubility, stability, and transcorneal permeation of Δ⁸-THC. Thus, topical ophthalmic formulations containing Δ⁸-THC and modified beta CDs may show markedly improved ocular bioavailability.     

Induction changes in photosystems I and II in plant leaves upon modulation of membrane ion transport

The steady-state regime of linear photosynthetic electron transport implies concerted operation of photosystems I and II (PSI and PSII) in plant leaves. Acidification of the thylakoid lumen is known to cause down-regulation of PSII photochemical activity but it is not yet clear how the proton accumulation in the lumen affects the PSI activity and coordinated operation of the two photosystems in intact leaves. Chlorophyll fluorescence and absorbance of oxidized chlorophyll P700 in the near-infrared region ΔA _810–870 (ΔA ₈₁₀) are convenient noninvasive indicators of the redox state of PSII and PSI components, respectively. Simultaneous measurements of chlorophyll fluorescence and ΔA ₈₁₀ in pea leaves revealed that some kinetic stages in the induction curves occur synchronously both in dark-adapted and preilluminated leaves. After the treatment of leaves with ionophores promoting or inhibiting the light-induced thylakoid pH gradient (valinomycin, nigericin, monensin), the induction curves of ΔA ₈₁₀ and chlorophyll fluorescence were consistently modified. The results suggest that characteristic stages of ΔA ₈₁₀ induction curve, representing the second and the third waves of P700 photooxidation, are closely related to ΔpH generation, although the bases of ΔpH dependence differ for these two stages. The second wave of ΔA ₈₁₀ depends presumably on stroma alkalinization as a precondition for photoactivation of electron flow from PSI to terminal acceptors. The third wave of ΔA ₈₁₀ is apparently due to retardation of electron flow between PSII and PSI upon acidification of the lumen.     

Variation in carbon isotope discrimination within and among Sphagnum species in a temperate wetland

Field samples of bryophytes are highly variable in carbon isotope discrimination values (Δ, a measure of ¹³CO₂ uptake relative to ¹²CO₂), but it is unknown what affects Δ under field conditions, or how variation in Δ relates to bryophyte performance. This study employed field and greenhouse common garden studies to evaluate the influence of microsite, seasonal, and genetic variation on Δ in peatmosses. Three species of Sphagnum that occupy hollow (S. recurvum), carpet (S. palustre), and hummock (S. tenerum) habitats were sampled for relative growth rates (RGR), C:N ratio, and Δ throughout a growing season. Values of Δ ranged from 19.0 to 27.1‰. This variation was unrelated to species (P=0.61). However, Δ varied seasonally (P<0.001), with lower discrimination in the spring (mean 22.5‰), followed by summer (23.8‰) and winter (24.7‰). There was also significant microsite variation (P=0.015) which disappeared when plants were grown in a common garden. In both spring and summer, microsite variation in Δ was inversely related to RGR (P<0.001), but unrelated to C:N ratios (P>0.08). These results suggest that environmental, not genetic, variation at microsites affects Δ in non-vascular plants. However, environmental control of Δ is unlike that in vascular plants where water limitation lowers chloroplastic demand and increases resistance to carbon uptake. In non-vascular plants, water limitation lowers chloroplastic demand and decreases resistance to carbon uptake. These processes have additive effects and generate high spatial and seasonal variability in Δ. Received: 29 April 1999 / Accepted: 8 November 1999     

Remodeling of the glycosylation pathway in the methylotrophic yeast Hansenula polymorpha to produce human hybrid-type N-glycans

As a step forward to achieve the generation of human complex-type N-glycans in the methylotrophic yeast Hansenula polymorpha, we here report the modification of the yeast glycosylation pathway by heterologous expression of the human gene encoding β-1,2-N-acetylglucosaminyltransferase I (GnTI). For the optimal expression of human GnTI in the yeast Golgi compartment, the catalytic domain of the GnTI was fused to various N-terminal leader sequences derived from the yeast type II membrane proteins. The vectors containing GnTI fusion constructs were introduced into the H. polymorpha och1Δ single and och1Δalg3Δ double mutant strains expressing the ER-targeted Aspergillus saitoi α-1,2 mannosidase, respectively. Both of the glycoengineered Hpoch1Δ and Hpoch1ΔHpalg3Δ strains were shown to produce successfully the hybrid-type glycans with a monoantennary N-acetylglucosamine (GlcNAc₁Man₅GlcNAc₂ and GlcNAc₁Man₃GlcNAc₂, respectively) by N-glycan profile analysis of cell wall proteins. Furthermore, by comparative analysis of byproduct formation and the glycosylation site occupancy, we propose that the Hpoch1Δ strain would be more suitable than the Hpoch1ΔHpalg3Δ strain as a host for the production of recombinant proteins with humanized glycans.