Microsecond Time-Resolved Absorption Spectroscopy Used to Study CO Compounds of Cytochrome bd from Escherichia coli

Cytochrome bd is a tri-heme (b558, b595, d) respiratory oxygen reductase that is found in many bacteria including pathogenic species. It couples the electron transfer from quinol to O2 with generation of an electrochemical proton gradient. We examined photolysis and subsequent recombination of CO with isolated cytochrome bd from Escherichia coli in oneelectron reduced (MV) and fully reduced (R) states by microsecond time-resolved absorption spectroscopy at 532-nm excitation. Both Soret and visible band regions were examined. CO photodissociation from MV enzyme possibly causes fast (t,1.5 ms) electron transfer from heme d to heme b595 in a small fraction of the protein, not reported earlier. Then the electron migrates to heme b558 (t,16 ms). It returns from the b-hemes to heme d with t,180 ms. Unlike cytochrome bd in the R state, in MV enzyme the apparent contribution of absorbance changes associated with CO dissociation from heme d is small, if any. Photodissociation of CO from heme d in MV enzyme is suggested to be accompanied by the binding of an internal ligand (L) at the opposite side of the heme. CO recombines with heme d (t,16 ms) yielding a transient hexacoordinate state (CO-Fe2+ -L). Then the ligand slowly (t,30 ms) dissociates from heme d. Recombination of CO with a reduced heme b in a fraction of the MV sample may also contribute to the 30-ms phase. In R enzyme, CO recombines to heme d (t,20 ms), some heme b558 (t,0.2–3 ms), and finally migrates from heme d to heme b595 (t,24 ms) in ,5% of the enzyme population. Data are consistent with the recent nanosecond study of Rappaport et al. conducted on the membranes at 640-nm excitation but limited to the Soret band. The additional phases were revealed due to differences in excitation and other experimental conditions

Figs 131–142 in Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

Figs 131–142. Manzuma nigritibia (Caporiacco, 1941) gen. et comb. nov., holotype of Saitis nigritibiis, ♂ (137–138), ♂♂ from Ethiopia (Awash NP, MRAC) (131–136), holotype of Aelurillus reconditus, ♀ (139–142). 131–132. Male palp. 131. Ventral view. 132. Retrolateral view. 133–138. Embolic division. 133, 138. Dorsal view. 134. Prolateral view. 135. Ventral view. 136–137. Retrolateral view. 139. Diagrammatic course of the insemination ducts. 140–142. Epigyne. 140. Ventral view. 141. Ventroapical view. 142. Spermathecae, dorsal view. Scale bars: 0.1 mm.Published as part of Azarkina, Galina N., 2020, Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae), pp. 1-47 in European Journal of Taxonomy 611 on page 28, DOI: 10.5852/ejt.2020.611, http://zenodo.org/record/369857

Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

A new jumping spider genus, Manzuma gen. nov. (Salticidae Blackwall, 1841), is described, type species is Manzuma nigritibia (Caporiacco, 1941). Aelurillus reconditus Wesołowska & van Harten, 1994 is synonymized with Rafalus nigritibiis (Caporiacco, 1941). Four new combinations are proposed: M. jocquei gen. et comb. nov. (ex Aelurillus), M. kenyaensis gen. et comb. nov. (ex Langelurillus), M. lympha gen. et comb. nov. (ex Rafalus) and M. nigritibia gen. et comb. nov. (ex Rafalus). Three species, M. botswana gen. et sp. nov. (♂♀, Botswana and Republic of South Africa), M. petroae gen. et sp. nov. (♂♀, Republic of South Africa) and M. tanzanica gen. et sp. nov. (♂, Tanzania), are described. The male of M. kenyaensis gen. et comb. nov. and female of M. lympha gen. et comb. nov. are described for the first time. A new aelurilline synapomorphy is proposed. Identification key for males is provided

<i>Manzuma</i> gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

A new jumping spider genus, Manzuma gen. nov. (Salticidae Blackwall, 1841), is described, type species is Manzuma nigritibia (Caporiacco, 1941). Aelurillus reconditus Wesołowska &amp; van Harten, 1994 is synonymized with Rafalus nigritibiis (Caporiacco, 1941). Four new combinations are proposed: M. jocquei gen. et comb. nov. (ex Aelurillus), M. kenyaensis gen. et comb. nov. (ex Langelurillus), M. lympha gen. et comb. nov. (ex Rafalus) and M. nigritibia gen. et comb. nov. (ex Rafalus). Three species, M. botswana gen. et sp. nov. (♂♀, Botswana and Republic of South Africa), M. petroae gen. et sp. nov. (♂♀, Republic of South Africa) and M. tanzanica gen. et sp. nov. (♂, Tanzania), are described. The male of M. kenyaensis gen. et comb. nov. and female of M. lympha gen. et comb. nov. are described for the first time. A new aelurilline synapomorphy is proposed. Identification key for males is provided.</p

Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

A new jumping spider genus, Manzuma gen. nov. (Salticidae Blackwall, 1841), is described, type species is Manzuma nigritibia (Caporiacco, 1941). Aelurillus reconditus Wesołowska & van Harten, 1994 is synonymized with Rafalus nigritibiis (Caporiacco, 1941). Four new combinations are proposed: M. jocquei gen. et comb. nov. (ex Aelurillus), M. kenyaensis gen. et comb. nov. (ex Langelurillus), M. lympha gen. et comb. nov. (ex Rafalus) and M. nigritibia gen. et comb. nov. (ex Rafalus). Three species, M. botswana gen. et sp. nov. (♂♀, Botswana and Republic of South Africa), M. petroae gen. et sp. nov. (♂♀, Republic of South Africa) and M. tanzanica gen. et sp. nov. (♂, Tanzania), are described. The male of M. kenyaensis gen. et comb. nov. and female of M. lympha gen. et comb. nov. are described for the first time. A new aelurilline synapomorphy is proposed. Identification key for males is provided

Figs 182–187 in Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

Figs 182–187. Manzuma petroae gen. et sp. nov., general appearance of live ♂ from South Africa, photos © Vida van der Walt.Published as part of Azarkina, Galina N., 2020, Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae), pp. 1-47 in European Journal of Taxonomy 611 on page 35, DOI: 10.5852/ejt.2020.611, http://zenodo.org/record/369857

Fig. 200 in Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

Fig. 200. Collecting localities of seven species of Manzuma gen. nov.Published as part of Azarkina, Galina N., 2020, Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae), pp. 1-47 in European Journal of Taxonomy 611 on page 38, DOI: 10.5852/ejt.2020.611, http://zenodo.org/record/369857

Figs 154–160 in Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

Figs 154–160. Manzuma petroae gen. et sp. nov., holotype, ♂ (154–155) and paratype, ♂ from Tuinplaas (NCA 2016/382) (156–160). 154–155. Male palp. 154. Ventral view. 155. Retrolateral view. 156–160. Embolic division. 156. Dorsal view. 157. Retrolatero-apical view. 158. Retrolateral view. 159. Prolateral view. 160. Ventral view. Scale bars: 0.1 mm.Published as part of Azarkina, Galina N., 2020, Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae), pp. 1-47 in European Journal of Taxonomy 611 on page 32, DOI: 10.5852/ejt.2020.611, http://zenodo.org/record/369857

Figs 1–3. Aelurillus v in Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae)

Figs 1–3. Aelurillus v-insignitus (Clerck, 1757). 1–3. Spermathecae. 1. Ventral view. 2. Dorsal view. 3. Apical view. Scale bars: 0.1 mm.Published as part of Azarkina, Galina N., 2020, Manzuma gen. nov., a new aelurilline genus of jumping spiders (Araneae, Salticidae), pp. 1-47 in European Journal of Taxonomy 611 on page 3, DOI: 10.5852/ejt.2020.611, http://zenodo.org/record/369857

Stimulation of Menaquinone-Dependent Electron Transfer in the Respiratory Chain of Bacillus subtilis by Membrane Energization

At a pH of ≤7, respiration of Bacillus subtilis cells on endogenous substrates shut down almost completely upon addition of an uncoupler (carbonyl cyanide m-chlorophenylhydrazone [CCCP]) and a K(+)-ionophore (valinomycin). The same effect was observed with cell spheroplasts lacking the cell wall. The concentration of CCCP required for 50% inhibition of the endogenous respiration in the presence of K(+)-valinomycin was below 100 nM. Either CCCP or valinomycin alone was much less efficient than the combination of the two. The inhibitory effect was easily reversible and depended specifically on the H(+) and K(+) concentrations in the medium. Similar inhibition was observed with respect to the reduction of the artificial electron acceptors 2,6-dichlorophenolindophenol (DCPIP) and N,N,N′,N′-tetramethyl-p-phenylenediamine cation (TMPD(+)), which intercept reducing equivalents at the level of menaquinol. Oxidation of the reduced DCPIP or TMPD in the bacterial cells was not sensitive to uncoupling. The same loss of the electron transfer activities as induced by the uncoupling was observed upon disruption of the cells during isolation of the membranes; the residual activities were not further inhibited by the uncoupler and ionophores. We conclude that the menaquinone-dependent electron transfer in the B. subtilis respiratory chain is facilitated, thermodynamically or kinetically, by membrane energization. A requirement for an energized state of the membrane is not a specific feature of succinate oxidation, as proposed in the literature, since it was also observed in a mutant of B. subtilis lacking succinate:quinone reductase as well as for substrates other than succinate. Possible mechanisms of the energy-dependent regulation of menaquinone-dependent respiration in B. subtilis are discussed