The dependence of intracellular ATP level on the nutrition mode of the acidophilic bacteria Sulfobacillus thermotolerans and Alicyclobacillus tolerans

The dynamics of the ATP pool in the aerobic spore-forming acidothermophilic mixotrophic bacteria Sulfobacillus thermotolerans Kr1T and Alicyclobacillus tolerans K1T were studied in the course of their chemolithoheterotrophic, chemoorganoheterotrophic, and chemolithoautotrophic growth. It was established that, during mixotrophic growth, the maximum ATP concentrations in the cells of S. thermotolerans Kr1 and A. tolerans K1 were 3.8 and 0.6 nmol/mg protein, respectively. The ATP concentrations in sulfobacilli and alicyclobacilli during organotrophic growth were 2.2 and 3.1 nmol/mg protein, respectively. In the cells of the obligately heterotrophic bacterium Alicyclobacillus cycloheptanicus 4006T, the maximum ATP concentration was several times higher and reached 12.3 nmol/mg protein. During lithotrophic growth, the maximum values of the ATP concentration in the cells of S. thermotolerans Kr1 and A. tolerans K1 were 0.3 and <0.1 nmol/mg protein, respectively; in the cells of the autotrophic bacterium Acidithiobacillus ferrooxidans TFBk, the ATP content was about 60-300 times higher (17.0 nmol/mg protein). It is concluded that low ATP content is among the possible causes of growth cessation of S. thermotolerans Kr1 and A. tolerans K1 under auto- and heterotrophic conditions after several culture transfers.     

Clubroot resistance QTL are modulated by nitrogen input in <Emphasis Type="Italic">Brassica napus</Emphasis>

Key message

Nitrogen levels can modulate the effectiveness of clubroot resistance in an isolate- and host-specific manner. While the same QTL were detected under high and low nitrogen, their effects were altered.

Abstract

Clubroot, caused by Plasmodiophora brassicae, is one of the most damaging diseases of oilseed rape and is known to be affected by nitrogen fertilization. However, the genetic factors involved in clubroot resistance have not been characterized under nitrogen-limiting conditions. This study aimed to assess the variability of clubroot resistance under different nitrogen levels and to characterize the impact of nitrogen supply on genetic resistance factors. Linkage analyses and a genome-wide association study were conducted to detect QTL for clubroot resistance and evaluate their sensitivity to nitrogen. The clubroot response of a set of 92 diverse oilseed rape accessions and 108 lines derived from a cross between ‘Darmor-bzh’ (resistant) and ‘Yudal’ (susceptible) was studied in the greenhouse under high- and low-nitrogen conditions, following inoculation with the P. brassicae isolates eH and K92-16. Resistance to each isolate was controlled by a major QTL and a few small-effects QTL. While the same QTL were detected under both high and low nitrogen, their effects were altered. Clubroot resistance to isolate eH, but not K92-16, was greater under a low-N supply versus a high-N supply. New sources of resistance were found among the oilseed rape accessions under both low and high-N conditions. The results are discussed relative to the literature and from a crop improvement perspective.

     

<i>Trichoderma</i> spp. fostering growth on <i>Capsicum chinense</i> Jacq. seedlings and antagonistic against <i>Meloidogyne incognita</i>

Fourteen native strains of Trichoderma spp. from wildand agricultural pathosystems in the state of Yucatan, Mexico, with growth-promoting ability of Capsicum chinense Jacq. seedlings were evaluated and antagonistic effect of their filtrate against second-stage juveniles (J2) of Meloidogyne incognita. The strains Th05-02 and Th27-08 showed the best significant effects on plant hight variable increments 55.57 and 47.62%, theTh07-04 with 29.48% more root length, theTh02-01 and Th07-04 isolates increased from 48.71 to 84.61% in volume radical and 53.40% of total dry biomass. Statistical analysis (p≤0.001) of Th43 and Th43-13-14 filtrates caused 100% mortality at 24 and 48h. In the test of reversibility to 24 h after replacing the filtrates Th43-13, Th43-14, TH09-06 and TH20-07 by sterile distilled water, the J2 did not recover their viability, so they were considered as the best potential strains of Trichoderma spp. with antagonistic capacity in J2 of M.incognita.     

Physiological mechanism of the formation of life forms of herbaceous plants and their cenoses in phylogenesis related to changes in water supply (a quantitative approach)

Amodel of phylogenetic development of life forms of herbaceous plants is proposed on the basis of a multidisciplinary study of physiological and morphological characters of complete species composition of two herbaceous cenoses (meadow and steppe). The physiological mechanism of their formation in the context of changing water supply consists in the optimization of water deficiency and production capacities of their leafs, the emergence of most efficient species-level sprout forms (non-rosette, semi-rosette and rosette), and finally in the establishment of a definite proportion between these forms within the composition of a given herbaceous cenosis.     

Reference values of blood biochemical indices in Russian cosmonauts

In the period from 2000 to 2012, the values of 40 diagnostically significant biochemical indices in venous blood were determined during the preflight clinical and physiological examination of 28 Russian cosmonauts aged 35 to 54, members of the main and backup crews of missions on board the International Space Station. The examination was conducted 45-30 days prior to the launch. Since most cosmonauts performed several flights during this period and they were repeatedly included in backup crews, each of the cosmonauts participated in preflight examinations one to five times. The reference values were calculated for each of the studied indices. It was found that reference interval boundaries for 15 indices were narrower as compared to the generally accepted ranges. The upper boundaries of the reference ranges of the activities of a number of enzymes, as well as of the concentrations of some metabolites of energy and plasticity metabolism, were higher than the population’s mean values. Thus, it was found that Russian cosmonauts, being a specific professional team, had reference values of a number of blood biochemical indices that were different from the population’s mean values. This was due to the characteristics of selection, physical training, and psychic and emotional states of crew members during the preflight period.     

Chromosome stability in saccharomycete yeasts

Mutants with high instability of chromosome III designated Chl+ (chromosome loss) were obtained after irradiation with UV the Z4221-3c1 haploid disomic for chromosome III. The Chl+ mutants can be divided into two classes: 1) CL2, CL3, CL7, CL9, CL11, CL12, CL13 with elevated level of spontaneous inter- and intragenic recombination; 2) CL4, CL8 which unstable maintenance of chromosome III not accompanied with elevation of mitotic recombination frequency. The CL4 and CL8 mutants also reveal, in contrast to other mutants, unstable maintenance of artificial mini-chromosomes with chromosomal replicator ARS1 and centromeric loci CEN3, CEN4, CEN5, CEN6, CEN11. Substitution of ARS1 for other yeast replicators (ARS2, ARS of 2 micron plasmid) leads to no stabilization of mini-chromosomes in mutants. The noncentromeric plasmids containing homologous replicator (or replicators) from Candida maltosa are maintained with the same frequency both in wild type and in mutants. So, the stability of mini-chromosomes in CL4 and CL8 is not connected with uneffective replication of these chromosomes. Instability of chromosome III and mini-chromosomes in CL4 and CL8 is controlled by two nonallelic genes designated chl14 and chl18. We suppose that these genes control the process of centromere interaction with mitotic spindle microtubules.     

Synaptic Contacts of Neurons of Fascia Dentata Transplants with Nonspecific Targets in Neocortex of Recipients

We carried out an electron microscopy study of possible synaptic contacts of the neurons of intracortical transplants of the rat brain fascia dentata with targets in the recipient somatosensory cortex. The axons of fascia dentata granular cell and their synaptic terminals could be easily identified in the neocortex due to their distinct morphological features (mossy fibers), although the fascia dentate cells normally do not interact with the neocortex. Thin nonmyelenized mossy fibers were found in both an intermediate zone between the transplant and brain and in the adjacent brain. Their presynaptic buds, like in situ, had large size and formed characteristic terminal, intraterminal, and en passant multiple synaptic contacts and desmosome-like junctions. The aberrant nerve fibers used perykaryons, dendrites of varying diameter, and dendrite spikes of the somatosensory cortex pyramidal neurons as postsynaptic targets in the neocortex. In addition to vacant spaces that appeared in the brain as a result of transplantation, the ingrowing axons induced the formation of additional contact sites: deep invaginations of the plasmalemma of perykaryons, somatic spikes, terminal branchings of dendrites, and dendritic outgrowths of complex branched shape. These aberrant contacts were characterized by the presence of polyribosomes, endoplasmic reticulum cisternae, and mitochondria in the postsynaptic loci. Osmiophility and extension of desmosome-like junctions were also enhanced in such synapses. Thus, it was shown that mossy fibers ingrowing in the recipient neocortex were capable of forming cell-to-cell contacts with signs of functional synapses to atypical cell targets.     

The evolution of myrmicine ants: phylogeny and biogeography of a hyperdiverse ant clade (Hymenoptera: Formicidae)

This study investigates the evolutionary history of a hyperdiverse clade, the ant subfamily Myrmicinae (Hymenoptera: Formicidae), based on analyses of a data matrix comprising 251 species and 11 nuclear gene fragments. Under both maximum likelihood and Bayesian methods of inference, we recover a robust phylogeny that reveals six major clades of Myrmicinae, here treated as newly defined tribes and occurring as a pectinate series: Myrmicini, Pogonomyrmecini trib.n. , Stenammini, Solenopsidini, Attini and Crematogastrini. Because we condense the former 25 myrmicine tribes into a new six‐tribe scheme, membership in some tribes is now notably different, especially regarding Attini. We demonstrate that the monotypic genus Ankylomyrma is neither in the Myrmicinae nor even a member of the more inclusive formicoid clade—rather it is a poneroid ant, sister to the genus Tatuidris (Agroecomyrmecinae). Several species‐rich myrmicine genera are shown to be nonmonophyletic, including Pogonomyrmex, Aphaenogaster, Messor, Monomorium, Pheidole, Temnothorax and Tetramorium. We propose a number of generic synonymies to partially alleviate these problems (senior synonym listed first): Pheidole = Anisopheidole syn.n. = Machomyrma syn.n. ; Temnothorax = Chalepoxenus syn.n. = Myrmoxenus syn.n. = Protomognathus syn.n. ; Tetramorium = Rhoptromyrmex syn.n. = Anergates syn.n. = Teleutomyrmex syn.n. The genus Veromessor stat.r. is resurrected for the New World species previously placed in Messor; Syllophopsis stat.r. is resurrected from synonymy under Monomorium to contain the species in the hildebrandti group; Trichomyrmex stat.r. is resurrected from synonymy under Monomorium to contain the species in the scabriceps‐ and destructor‐groups; and the monotypic genus Epelysidris stat.r. is reinstated for Monomorium brocha. Bayesian divergence dating indicates that the crown group Myrmicinae originated about 98.6 Ma (95% highest probability density 87.9–109.6 Ma) but the six major clades are considerably younger, with age estimates ranging from 52.3 to 71.1 Ma. Although these and other suprageneric taxa arose mostly in the middle Eocene or earlier, a number of prominent, species‐rich genera, such as Pheidole, Cephalotes, Strumigenys, Crematogaster and Tetramorium, have estimated crown group origins in the late Eocene or Oligocene. Most myrmicine species diversity resides in the two sister clades, Attini and Crematogastrini, which are estimated to have originated and diversified extensively in the Neotropics and Paleotropics, respectively. The newly circumscribed Myrmicini is Holarctic in distribution, and ancestral range estimation suggests a Nearctic origin. The Pogonomyrmecini and Solenopsidini are reconstructed as being Neotropical in origin, but they have subsequently colonized the Nearctic region (Pogonomyrmecini) and many parts of the Old World as well as the Nearctic region (Solenopsidini), respectively. The Stenammini have flourished primarily in the northern hemisphere, and are most likely of Nearctic origin, but selected lineages have dispersed to the northern Neotropics and the Paleotropics. Thus the evolutionary history of the Myrmicinae has played out on a global stage over the last 100 Ma, with no single region being the principal generator of species diversity. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub: BB6829C4‐DA79‐45FE‐979E‐9749E237590E .