Enhanced hyphal body production by Entomophaga aulicae protoplasts in the presence of a neutral and a positively charged surface under mass fermentation conditions

1990 ◽  
Vol 68 (12) ◽  
pp. 2708-2713 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Glucose Utilization ◽  
Positive Charge ◽  
Maximum Level ◽  
Fermentation Conditions ◽  
Larval Stages ◽  
Charged Surfaces ◽  
Fermentation Vessel ◽  
Hyphal Body ◽  
Body Production ◽  
Positively Charged

The effects of two disks, one with a net neutral charge (Mylar) and one with a positive charge (polypropylene), on hyphal body production from protoplasts of the fungus Entomophaga aulicae under mass fermentation conditions were determined. The results were compared with those obtained with a vessel lacking a disk (control). The presence of either disk greatly enhanced hyphal body production, especially by day 4 of incubation. A maximum level of 94.1% hyphal body production was achieved using the disks as compared to a maximum level of 42% under control conditions. With the exception of aspartic acid, which was produced under control conditions and not utilized when the disks were present, the amino acids were removed from the medium earlier and (or) more completely in the presence of the disks. Glucose utilization and oxygen consumption were greater in the presence of the disks. The utilization of fermentation vessel configurations employing neutral or positively charged disks (surfaces) offers a method for greatly enhancing hyphal body production for biocontrol of the larval stages of forest defoliators. Key words: Entomophaga aulicae, hyphal body production, biological control, mass fermentation, neutral and positively charged surfaces.

Physiological studies with the fungus Entomophaga aulicae during morphogenesis in three different media under fermentation conditions

1993 ◽  
Vol 39 (7) ◽  
pp. 701-708
Author(s):  
Richard A. Nolan
Keyword(s):  
Amino Acid ◽  
Serum Albumin ◽  
Glucose Utilization ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Basal Medium ◽  
Fermentation Conditions ◽  
Hyphal Bodies ◽  
Hyphal Body ◽  
Body Production

The effects of three different media on amino acid uptake and production and glucose and oxygen utilization during protoplast growth and hyphal body production by the fungus Entomophaga aulicae under fermentation conditions were studied. The three media consisted of a basal medium plus either (i) 2.8% fetal calf serum, (ii) 0.8% tryptic soy broth plus 0.4% bovine serum albumin, or (iii) 0.8% tryptic soy broth plus 0.4% calcium caseinate. The protoplasts grew most rapidly (initial peaks on days 2 and 3) and hyphal bodies were detected first (day 3) in the media containing albumin and caseinate. The day 9 hyphal body yields were 3.1 × 107, 7.5 × 108, and 3.1 × 109/10 L in media containing the serum, albumin, and caseinate, respectively. Growth in the albumin and caseinate media also gave the first detectable glucose utilization (days 2 and 3, respectively) and this rapidly increased to 94.9 and 90.6% utilization, respectively, on day 4. Oxygen and glucose utilization were closely related. During protoplast growth prior to hyphal body production, the only common pattern detected was the initial utilization of glutamine in serum- and caseinate-containing media. During the initial period of hyphal body production, cysteic acid, threonine, serine, asparagine, leucine, tyrosine, phenylalanine, and arginine were first utilized and glycine, alanine, and ammonia were first produced in the albumin and caseinate media. At this time (days 3–5), glutamine, proline, cystine, and tryptophan were first utilized and valine and histidine were produced in the albumin medium, and methionine was first utilized and cystathionine produced in the caseinate medium. Four main patterns of overall amino acid utilization and production were identified. The delay in major protoplast growth in the basal medium plus fetal calf serum is felt to result from inhibition by free fatty acids in the serum. Protein utilization was not detected and its main function is considered to be enhancement of protoplast stability against fermentation shear forces.Key words: Entomophaga aulicae, physiology, fermentation growth, protoplasts, hyphal bodies.

Influence of a negatively charged surface (Teflon disk) on Entomophaga aulicae protoplast morphogenesis under mass fermentation conditions

1991 ◽  
Vol 69 (11) ◽  
pp. 2578-2581 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Metabolic Inhibitors ◽  
Charged Surface ◽  
Late Fusion ◽  
Developmental Patterns ◽  
Fermentation Conditions ◽  
Surface Mass ◽  
Early Fusion ◽  
Hyphal Body ◽  
Body Production ◽  
Positively Charged

The effects of a negatively charged surface (Teflon disk) on protoplast morphogenesis for the fungus Entomophaga aulicae under mass fermentation conditions were determined. The control consisted of a vessel lacking such a disk. In the presence of the disk the initial three and sequentially produced protoplast stages (spindle shaped, early fusion sphere, and late fusion sphere protoplasts) recycled with the early fusion sphere predominating. The production of the subsequent and walled stage (i.e., hyphal body) was suppressed. The results are in contrast with those obtained in a previous study using a neutral (Mylar) and a positively charged (polypropylene) disk in which hyphal body production was enhanced. This technique provides a new and subtle approach for altering protoplast developmental patterns which avoids the use of mutagens or added chemical metabolic inhibitors. Key words: Entomophaga aulicae, fungal protoplast morphogenesis, negatively charged surface, mass fermentation.

Effects of an altered developmental pattern on amino acid uptake for a protoplast isolate of the fungus Entomophaga aulicae under mass-fermentation conditions

1986 ◽  
Vol 32 (11) ◽  
pp. 855-860 ◽  
Author(s):  
Richard A. Nolan
Keyword(s):  
Amino Acid ◽  
Glucose Utilization ◽  
Amino Acid Uptake ◽  
Developmental Pattern ◽  
Acid Uptake ◽  
Late Fusion ◽  
Fermentation Conditions ◽  
Uptake Pattern ◽  
Hyphal Body ◽  
First Time

The effects of an altered developmental pattern on amino acid uptake for a protoplast isolate of the fungus Entomophaga aulicae were studied under mass-fermentation conditions. Isolate 655A had previously developed through the hyphal body stage, but subsequently lost this ability (then designated I655B) and then developed only as far as the germination of the late fusion sphere stage. This alteration in developmental pattern was accompanied by a shift in the overall amino acid uptake pattern. For comparative purposes, another isolate (I521) which developed only as far as the germination of the late fusion sphere stage was included. The general amino acid uptake patterns fell into three categories and emphasize the similarity of I521 and I655B: (i) earlier and more complete final utilization by isolates 521 and 655B for glutamine, leucine, aspartic acid, threonine, and methionine, (ii) earlier utilization by isolate 655A with more complete final utilization by isolates 521 and 655B for asparagine and proline, and (iii) earlier utilization by isolates 521 and 655A with more complete final utilization by isolates 521 and 655B for serine and tyrosine. The first detectable utilization of serine coincided with late fusion sphere germination for isolates 521 and 655B. During the rapid increase in hyphal body levels for I655A, all added amino acids (except proline, asparagine, and serine which were first utilized earlier) were utilized for the first time. Except for the timing of the initial day of detectable utilization, the pattern of glucose utilization was similar for all three isolates.

Positive charge modifications alter the ability of XIP to inhibit the plasma membrane calcium pump

1996 ◽  
Vol 271 (3) ◽  
pp. C736-C741 ◽  
Author(s):  
W. Xu ◽  
C. Gatto ◽  
M. A. Milanick
Keyword(s):  
Plasma Membrane ◽  
Positive Charge ◽  
Calcium Pump ◽  
Inhibitory Peptide ◽  
Ca Pump ◽  
Contact Points ◽  
Plasma Membrane Calcium Pump ◽  
Peptide Analogues ◽  
Positively Charged

Exchange inhibitory peptide (XIP; RRLLFYKYVYKRYRAGKQRG) is the shortest peptide that inhibits the plasma membrane Ca pump at high Ca (A. Enyedi, T. Vorherr, P. James, D. J. McCormick, A. G. Filoteo, E. Carafoli, and J. T. Penniston, J. Biol. Chem. 264: 12313-12321, 1989). Sulfosuccinimidyl acetate (SNA)-modified XIP does not inhibit the Ca pump; SNA neutralizes the positive charge on Lys at positions 7, 11, and 17. Peptide 2CK-XIP (RRLLFYRYVYRCYCAGRQKG) inhibits the pump, but the iodoacetamido-modified peptide does not inhibit. Three peptide analogues, in which 7, 11, and 17 were Ala, Cys, or Lys, inhibited about as well as XIP. SNA modification of these analogues (each with 1 Lys) did not inhibit. SNA modification of 2CK-XIP results in a peptide that does not inhibit; thus position 19 is important. Our results suggest that it is critical that position 19 be positively charged, that positions 7, 11, and 17 are important contact points between XIP and the Ca pump (with at least one positively charged), and that, whereas it is not essential that residues 12 and 14 be positive, they cannot be negative.

Hybrid Pigments Based on Montmorillonite and Anionic Dyes for Leather Finishing

2021 ◽  
Vol 320 ◽  
pp. 198-203
Author(s):  
Anna Bondaryeva ◽  
Olena Mokrousova ◽  
Olena Okhmat
Keyword(s):  
Maximum Level ◽  
Steric Factor ◽  
Anionic Dyes ◽  
Mineral Particles ◽  
High Level ◽  
Leather Finishing ◽  
Positively Charged ◽  
Sodium Form

The work is focused on obtaining hybrid pigments by adsorption of anionic dyes on positively charged montmorillonite. Modification of the sodium form of montmorillonite by chromium hydroxocomplexes was provided to ensure effective adsorption of anionic dyes on the surface of mineral particles. A high level of adsorption of anionic dyes as a result of steric factor was revealed. It was shown that the adsorption of dyes depended on the pH of the medium and was characterized by a maximum level at pH 4.5 – 6.0. The scheme of obtaining hybrid pigments, which were characterized by good сovering ability, resistance to stratification, especially saturated and intense colour was proposed.

Role of S4 positively charged residues in the regulation of Kv4.3 inactivation and recovery

2007 ◽  
Vol 293 (3) ◽  
pp. C906-C914 ◽  
Author(s):  
Matthew R. Skerritt ◽  
Donald L. Campbell
Keyword(s):  
Positive Charge ◽  
Voltage Sensitivity ◽  
Shaker Channels ◽  
Recovery From Inactivation ◽  
Kv4 Channels ◽  
Charged Residues ◽  
Arginine Residues ◽  
Voltage Sensing Domain ◽  
Positively Charged

The molecular and biophysical mechanisms by which voltage-sensitive K+ (Kv)4 channels inactivate and recover from inactivation are presently unresolved. There is a general consensus, however, that Shaker-like N- and P/C-type mechanisms are likely not involved. Kv4 channels also display prominent inactivation from preactivated closed states [closed-state inactivation (CSI)], a process that appears to be absent in Shaker channels. As in Shaker channels, voltage sensitivity in Kv4 channels is thought to be conferred by positively charged residues localized to the fourth transmembrane segment (S4) of the voltage-sensing domain. To investigate the role of S4 positive charge in Kv4.3 gating transitions, we analyzed the effects of charge elimination at each positively charged arginine (R) residue by mutation to the uncharged residue alanine (A). We first demonstrated that R290A, R293A, R296A, and R302A mutants each alter basic activation characteristics consistent with positive charge removal. We then found strong evidence that recovery from inactivation is coupled to deactivation, showed that the precise location of the arginine residues within S4 plays an important role in the degree of development of CSI and recovery from CSI, and demonstrated that the development of CSI can be sequentially uncoupled from activation by R296A, specifically. Taken together, these results extend our current understanding of Kv4.3 gating transitions.

scholarly journals Constructing Positively Charged Thin-Film Nanocomposite Nanofiltration Membranes with Enhanced Performance

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2526
Author(s):  
Wenyao Shao ◽  
Chenran Liu ◽  
Tong Yu ◽  
Ying Xiong ◽  
Zhuan Hong ◽  
...  
Keyword(s):  
Thin Film ◽  
Heavy Metal ◽  
Water Flux ◽  
Water Contact ◽  
Salt Rejection ◽  
Thin Film Composite ◽  
Charged Surfaces ◽  
Active Layers ◽  
Positively Charged ◽  
Thin Film Nanocomposite

Using polyethylenimine (PEI) as the aqueous reactive monomers, a positively charged thin-film nanocomposite (TFN) nanofiltration (NF) membrane with enhanced performance was developed by successfully incorporating graphene oxide (GO) into the active layer. The effects of GO concentrations on the surface roughness, water contact angle, water flux, salt rejection, heavy metal removals, antifouling property, and chlorine resistance of the TFN membranes were evaluated in depth. The addition of 20 ppm GO facilitated the formation of thin, smooth, and hydrophilic nanocomposite active layers. Thus, the TFN-PEI-GO-20 membrane showed the optimal water flux of 70.3 L·m−2·h−1 without a loss of salt rejection, which was 36.8% higher than the thin-film composite (TFC) blank membrane. More importantly, owing to the positively charged surfaces, both the TFC-PEI-blank and TFN-PEI-GO membranes exhibited excellent rejections toward various heavy metal ions including Zn2+, Cd2+, Cu2+, Ni2+, and Pb2+. Additionally, compared with the negatively charged polypiperazine amide NF membrane, both the TFC-PEI-blank and TFN-PEI-GO-20 membranes demonstrated superior antifouling performance toward the cationic surfactants and basic protein due to their hydrophilic, smooth, and positively charged surface. Moreover, the TFN-PEI-GO membranes presented the improved chlorine resistances with the increasing GO concentration.

THE EFFECT OF PROCOAGULANT PHOSPHOLIPID VESICLES WITH NET POSITIVE CHARGE ON THE ACTIVITY OF PROTHROMBINASE

1987 ◽  
Author(s):  
J Rosing ◽  
H Speijer ◽  
J W P Govers-Riemslag ◽  
R F A Zwaal
Keyword(s):  
Vitamin K ◽  
Negative Charge ◽  
Positive Charge ◽  
Coagulation Factor ◽  
Phospholipid Vesicles ◽  
Electrostatic Model ◽  
Acidic Phospholipid ◽  
Positively Charged ◽  
Net Positive Charge ◽  
Prothrombin Activation

It is generally thought that procoagulant phospholipid surfaces that promote the activation of vitamin K-dependent coagulation factors should have a net negative charge in order to promote calcium-dependent binding of the enzymes (FVIIa, FIXa and FXa) and substrates (prothrombin and FX) of the coagulation factor-activating complexes. Two models have been proposed to explain calcium-mediated association of vitamin K-dependent proteins with phospholipid: a) an electrostatic model, in which a positively-charged protein-calcium complex is attracted by a negatively-charged phospholipid surface and b) a chelation model in which a coordination complex is formed between calcium ions, γ-carboxyglutamic acids of the proteins and negatively-charged membrane phospholipids. To study the effect of the electrostatic potential of phospholipid vesicles on their activity in the pro-thrombinase complex the net charge of vesicles was varied by introduction of varying amounts of positively-charged stearylamine in the membrane surface. Introduction of 0-15 mole% stearylamine in phospholipid vesicles that contained 5 mole% phosphatidylseri-ne (PS) hardly affected their activity in prothrombin activation. Electrophoretic analysis showed that vesicles with > 5 mole% stearylamine had a net positive charge. The procoagulant activity of vesicles that contained phosphatidic acid, phosphatidylglyce-rol, phosphatidylinositol or phosphatidyl-glactate (PLac) as acidic phospholipid was much more effected by incorporation of stearylamine. Amounts of stearylamine that compensated the negative charge of acidic phospholipid caused considerable inhibition of the activity of the latter vesicles in prothrombin activation. The comparison of vesicles containing PS and PLac as acidic phospholipid is of special interest. PS and PLac only differ by the presence of NH+ 3-group in the serine moiety of PS. Thus, in spite of the fact that vesicles with PLac are more negatively charged than vesicles with PS, they are less procoagulant. Our results show that a) although procoagulant membranes have to contain acidic phospholipids there is no requirement for a net negative charge, b) the amino group of phosphatidylserine has an important function in the interaction of procoagulant membranes with vitamin K-dependent proteins and c) the chelation model can satisfactorily explain calcium-mediated lipid-protein association.

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