Subpicosecond resonance Raman spectra of the early intermediates in the photocycle of bacteriorhodopsin

The resonance Raman spectra are presented for the species formed during the photocycle of bacteriorhodopsin (bR) on a timescale of 800-900 fs. In the ethylenic stretch region two intermediates were found with frequencies of 1,510 and 1,518 cm^-1, corresponding to species with optical absorption maxima at 660 and 625 nm, respectively. This leads to the assignment of the 1,518 cm^-1 band to the J₆₂₅ intermediate. In the fingerprint region, the appearance of a vibration at 1,195 cm^-1 strongly suggests that the isomerization indeed has taken place in a time less than the pulsewidth of our laser. This supports the previous proposals made on the basis of the optical spectra. The spectra are compared with those observed in tens of picoseconds up to nanoseconds.     

Inheritance of lambda-cyhalothrin resistance in the predator lady beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae)

Lambda-cyhalothrin is a pyrethroid insecticide widely used to control pests in various crop ecosystems, in which the lady beetle occurs naturally. Therefore, lady beetle populations are exposed to lambda-cyhalothrin sprays that may foster tolerance to this insecticide. This study was conducted to confirm the occurrence of resistance in the lady beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae) to lambda-cyhalothrin and to characterize the inheritance of resistance after eight progressive selection with insecticide dosages based on the LD₅₀ determined for the F1 generation. Dose–mortality curves were determined for parental populations, F1 hybrids and backcross progenies. Parameters regarding the heritability of resistance to lambda-cyhalothrin in E. connexa allow estimating 10-fold increase in the initial LD₅₀ after 54.5 generations of successive selections. The resistance of E. connexa to lambda-cyhalothrin was characterized as autosomally inherited and incompletely dominant, and influenced by a major gene with possible influence of secondary genes. Additionally, the resistance in E. connexa varies from functionally dominant to functionally recessive depending on the dose used. These findings indicate that insecticide resistance in E. connexa can be selected in the field as determined for field-collected individuals, and subsequently enhanced under laboratory conditions. Its characterization presented here is an important step toward linking biological and chemical control within pest management regarding the lady beetle and lambda-cyhalothrin targeting different pest groups.     

Professor Dr. Geoffrey Burnstock (1929–2020)

Purinergic Signalling -     

The responses of auditory ventral-cord neurons ofLocusta migratoria to vibration stimuli

Summary Most of the auditory neurons in the ventral nerve cord ofLocusta migratoria carry information not only from the tympanal organs but also from the subgenual organs (vibration sensors). Six of the eight neuron types studied electrophysiologically respond to at least these two modalities. Artificial sounds (white noise and pure tones varying in frequency and intensity) and sinusoidal vibration (200 Hz with an acceleration of 15.8 cm/s₂ or 2000 Hz and 87 cm/s₂) were used as stimuli.Complex excitatory and/or inhibitory interactions of the signals from both tympanal organs form the discharge patterns of auditory ventral-cord neurons in response to stimulation with air-borne sound. Normally the input of the ipsilateral sense organ dominates. The response patterns of these same neurons elicited by vibration stimuli are formed differently, as follows: (1) the sensory inputs of all subgenual organs are integrated in the responses of the ventral-cord neurons; in a single neuron they have either excitatory or inhibitory effects, but not both. (2) The more legs vibrated, the larger is the response. (3) The subgenual organs in the middle legs are most effective, those in the hind legs least so. (4) Ipsilateral vibration has more effect than contralateral.The six auditory neurons react to vibration combined with air-borne sound in different ways. The B neuron is the only one inhibited by vibration stimuli. The G neuron has been studied more intensively; because its anatomical arrangement and the location of the endings of the subgenual receptor fibers are known, it could be inferred from effects of transection of the connectives that interneurons are interposed between receptor cells and the G neuron.Part of the program Sonderforschungsbereich 114 (Bionach) Bochum, under the auspices of the Deutsche Forschungsgemeinschaft, with the support of the Slovenic Research Society (RSS)     

Oral Antibiotic Treatment of Mice Exacerbates the Disease Severity of Multiple Flavivirus Infections

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Cofactor‐induced reversible folding of Flavodoxin‐4 from Lactobacillus acidophilus

Flavodoxins in combination with the flavin mononucleotide (FMN) cofactor play important roles for electron transport in prokaryotes. Here, novel insights into the FMN‐binding mechanism to flavodoxins‐4 were obtained from the NMR structures of the apo‐protein from Lactobacillus acidophilus (YP_193882.1) and comparison of its complex with FMN. Extensive reversible conformational changes were observed upon FMN binding and release. The NMR structure of the FMN complex is in agreement with the crystal structure (PDB ID: 3EDO ) and exhibits the characteristic flavodoxin fold, with a central five‐stranded parallel β–sheet and five α‐helices forming an α/β‐sandwich architecture. The structure differs from other flavoproteins in that helix α2 is oriented perpendicular to the β‐sheet and covers the FMN‐binding site. This helix reversibly unfolds upon removal of the FMN ligand, which represents a unique structural rearrangement among flavodoxins.     

Cerebral Circulation Time is Prolonged and Not Correlated with EDSS in Multiple Sclerosis Patients: A Study Using Digital Subtracted Angiography

Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27s) and control group (mean = 2.8s; sd = 0.51s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process.     

The epsilon-isoform of PKC mediates the hypertonic activation of cation channels in confluent monolayers of rat hepatocytes.

We were interested whether PKC alpha, delta, epsilon or zeta is the isoform actually employed in the activation of hypertonicity-induced cation channels (HICCs) in primary cultures of rat hepatocytes. Quantitative SDS-page and Western-blot experiments revealed that PKC alpha, delta and epsilon were stimulated by Indolactam V (as a DAG substitute for activation of c and nPKCs) but that only PKC delta and epsilon did respond to hypertonic stress. Furthermore, chelation of intracellular Ca(++) by BAPTA-AM did not alter HICC activation in cable-analysis experiments whereas Indolactam V as well as V8 (an Indolactam derivative specific for PKC delta and epsilon) activated HICC currents under isotonic conditions. Finally, by use of Rottlerin (as an inhibitor exhibiting a slight preference for PKC delta over epsilon) PKC epsilon could be identified as the most likely isoform responsible for the activation of the HICC.