Heterozygous Seryl-tRNA Synthetase 1 Variants Cause Charcot-Marie-Tooth Disease.

OBJECTIVE: Despite the increasing number of genes associated with Charcot-Marie-Tooth (CMT) disease, many patients currently still lack appropriate genetic diagnosis for this disease. Autosomal dominant mutations in aminoacyl-tRNA synthetases (ARSs) have been implicated in CMT. Here, we describe causal missense mutations in the gene encoding seryl-tRNA synthetase 1 (SerRS) for 3 families affected with CMT. METHODS: Whole-exome sequencing was performed in 16 patients and 14 unaffected members of 3 unrelated families. The functional impact of the genetic variants identified was investigated using bioinformatic prediction tools and confirmed using cellular and biochemical assays. RESULTS: Combined linkage analysis for the 3 families revealed significant linkage (Zmax LOD = 6.9) between the genomic co-ordinates on chromosome 1: 108681600-110300504. Within the linkage region, heterozygous SerRS missense variants segregated with the clinical phenotype in the 3 families. The mutant SerRS proteins exhibited reduced aminoacylation activity and abnormal SerRS dimerization, which suggests the impairment of total protein synthesis and induction of eIF2α phosphorylation. INTERPRETATION: Our findings suggest the heterozygous SerRS variants identified represent a novel cause for autosomal dominant CMT. Mutant SerRS proteins are known to impact various molecular and cellular functions. Our findings provide significant advances on the current understanding of the molecular mechanisms associated with ARS-related CMT. ANN NEUROL 2023;93:244-256.

Chemical constituents from the endophytic fungus Aspergillus sp. S3 of Hibiscus tiliaceus.

A new sterol, aspersterol E (1), a newly discovered alkaloid, asperginine A (2), and five known compounds (3-7) were obtained from the endophytic fungus Aspergillus sp. S3 of Hibiscus tiliaceus Linn. The compounds were extracted from their fermentation products using silica gel, ODS C18, and semi-preparative HPLC. The structure of each compound was determined through spectroscopic analysis. All the obtained compounds (1-7) were evaluated for their cytotoxic activity against the mouse pre-gastric cancer cell line MFC by using the MTT assay. The IC50 values of compounds 1, 2, 3, and 5 were found to be 153.43 µM, 61.25 µM, 73.19 µM, and 181.69 µM respectively.

Ame-miR-980-3p participates in autophagy-mediated midgut remodelling in Apis mellifera via targeting Atg2B.

Autophagy is a process that serves to degrade damaged proteins and organelles, thereby promoting cell homeostasis, differentiation, development and survival. Many miRNAs have been found to have regulatory roles in autophagy. In insects, it has been shown that autophagy is involved in hormone-regulated programmed cell death during metamorphic midgut remodelling. However, whether this is also true during the remodelling of the honey bee midgut is unclear. In the present study, we explored the relationship between autophagy and midgut remodelling and sought to identify miRNAs involved in this physiological process. We found that autophagy occurred during midgut remodelling and that the inhibition of autophagy resulted in midgut dysplasia in prepupae. Differentially expressed miRNAs enriched in the autophagy signalling pathway during midgut remodelling were identified by small RNA-seq. Ame-miR-980-3p, which targets the autophagy-related gene Atg2B, was screened out. Furthermore, abnormal expression of ame-miR-980-3p in the pupal stage led to the thinning of the midgut wall of newly emerged bees (NE). When ame-miR-980-3p expression was inhibited, the intestinal villi of NE bees became significantly shorter and sparse, and the lipid signal in the peritrophic matrix of Pb almost disappeared, indicating that the adult midgut was underdeveloped and the lipid absorption ability was weakened. Taken together, ame-miR-980-3p targeted Atg2B to participate in the regulation of midgut autophagy in the pupae, and the abnormal expression of ame-miR-980-3p would interfere with cell proliferation and death in the process of midgut remodelling, hinder the formation of adult midgut and eventually lead to adult midgut dysplasia and affect the lipid absorption function of the midgut in Apis mellifera.

Honey bee larval culture in vitro: gut emptying determines the transition from larva to prepupa and recombinant AccApidaecin improves antibacterial activity.

In vitro rearing of honey bee larvae is ideal for bioassay studies; no honey bee stable cell lines are available. Inconsistency of internal development staging of reared larvae and a susceptibility to contamination are common problems encountered. Standardized protocols on rearing larvae in vitro to make the larvae growth and development more similar to that of natural colonies are necessary to ensure the accuracy of experimental results and promote honey bee research as a model organism. Here, we concluded that when larval fasting weight was >160 mg, the time point of gut emptying can be defined as the critical point separating the larval and prepupal stages. In this way, we can conduct precise studies on the prepupal stage, such as organ remodeling during metamorphosis. Simultaneously, we further verified that recombinant AccApidaecin in genetic engineered bacteria added to the larval diet upregulated antibacterial peptide gene expression, and did not stimulate the stress response in larvae, nor did it affect the pupation rate or eclosion rate. This demonstrated that feeding recombinant AccApidaecin can enhance the individual antibacterial ability at the molecular level.

AmAtg2B-Mediated Lipophagy Regulates Lipolysis of Pupae in Apis mellifera.

Lipophagy plays an important role in regulating lipid metabolism in mammals. The exact function of autophagy-related protein 2 (Atg2) has been investigated in mammals, but research on the existence and functions of Atg2 in Apis mellifera (AmAtg2) is still limited. Here, autophagy occurred in honeybee pupae, which targeted lipid droplets (LDs) in fat body, namely lipophagy, which was verified by co-localization of LDs with microtubule-associated protein 1A/1B light chain 3 beta (LC3). Moreover, AmAtg2 homolog B (AmAtg2B) was expressed specifically in pupal fat body, which indicated that AmAtg2B might have special function in fat body. Further, AmAtg2B antibody neutralization and AmAtg2B knock-down were undertaken to verify the functions in pupae. Results showed that low expression of AmAtg2B at the protein and transcriptional levels led to lipophagy inhibition, which down-regulated the expression levels of proteins and genes related to lipolysis. Altogether, results in this study systematically revealed that AmAtg2B interfered with lipophagy and then caused abnormal lipolysis in the pupal stage.

Assessment of the oral health literacy and oral health behaviors among nurses in China: a cross-sectional study.

PURPOSE: Oral health is important for general health; nurses are expected to possess good oral health awareness and work together for public oral health promotion. The purpose of this study is to investigate oral health literacy (OHL)and oral health behaviors of nurses, and explore the association between oral health literacy with demographic variables and oral health behaviors. METHODS: A cross-sectional study in a tertiary hospital was conducted using a short-form Health Literacy in Dentistry-14 (HeLD-14) and a 16-items oral health behaviors questionnaire. Information about the subjects' demographic details including age, gender, place of residence, marital status, marital status, education level, monthly household income, working experience, etc. were collected. Independent sample t- test, One- way ANOVA, and multivariable regression were used to identify the association of oral health literacy with demographic variables and oral health behaviors. RESULTS: A total number of 317 nursing nurses participated in the survey, with a mean OHL score of 36.72, SD10.531, 21.8% were categorized as good, 34.1% medium and 44.2% poor oral health literacy; monthly household income, self-rated oral health, brushing time, use of fluoride toothpaste, and regular oral examination were signficantly associated with OHL scores. CONCLUSION: The overall oral health literacy of the nurse population is at a moderate to low level. These findings may help to map and design an oral health education intervention to improve oral health literacy amongst nurses, especially nurses with low monthly household income and poor self-assessed oral health status. Nursing administrators and nursing educators should pay more attention to the oral health status of the nurse population.

Siccirubricoccus phaeus sp. nov., isolated from oil reservoir water and emended description of the genus Siccirubricoccus.

A Gram-staining-negative, non-motile, aerobic bacterium, designated 1-3T, was isolated from oil reservoir water collected from Liaohe oilfield, north-east of China. Growth was observed at 15-40 °C (optimum 37 °C) and pH 6-10 (optimum 7). The strain can grow under nitrogen-limiting condition. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate was most closely related to Siccirubricoccus deserti SYSU D8009T (96.7%), followed by Paracraurococcus ruber NS89T (95.7%) and Belnapia rosea CPCC 100156T (94.9%). Genome sequencing revealed a genome size of 6.43 Mbp and a G+C content of 71.3 mol%. The average nucleotide identity values and digital DNA-DNA hybridization between 1-3T and the reference strains were all below the cut-off level (95-96% and 70%, respectively) for species delineation. The strain possessed the cytochrome P450 enzyme, which has the potential to degrade oil. The respiratory quinone was Q-10 and the major fatty acids were summed feature 8 (C18:1 ω7c/C18:1 ω6c, 38.8%), C16:0 (25.6%) and C19:0 cyclo ω8c (22.5%). The polar lipids of strain 1-3T comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and three unidentified aminolipids. Based on the genotypic and phenotypic characteristics, strain 1-3T represents a novel species of genus Siccirubricoccus, for which the name Siccirubricoccus phaeus sp. nov. is proposed. The type strain of Siccirubricoccus phaeus is 1-3T (= CGMCC 1.16799T = LMG 31398T).

Frigidibacter oleivorans sp. nov., isolated from a deep well with oil reservoir water.

A Gram-stain-negative, rod-shaped bacterium, designated XJ4T, was isolated from oil-contaminated water, collected from Xinjiang Province, north-west PR China (45° 1' 27″ N, 85° 6' 14″ E). Growth occurred at 20-45 °C (optimum, 30 °C) and pH 6.0-10.0 (optimum, pH 6.0-7.0). Strain XJ4T could tolerate up to 7 % (w/v) NaCl and grow optimally in the absence of NaCl. Phylogenetic analysis based on comparative sequence analysis of 16S rRNA gene sequences indicated that strain XJ4T belonged to the genus Frigidibacter, and that was closely related to Frigidibacter mobilis cai42T (97.2 %), Frigidibacter albus SP32T (97.0 %) and Rhodobacter aestuarii JA296T (97.0 %). The average nucleotide identity values between XJ4T and three type strains were 77.9, 77.6 and 71.9 %, respectively. The DNA G+C content of strain XJ4T was 69.5 mol%. The sole respiratory quinone was Q-10. The major cellular fatty acid was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C18 : 0 and 11-methyl C18 : 1 ω7c. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids, an unidentified aminolipid and unidentified lipids. On the basis of phenotypic, chemotaxonomic and phylogenetic analyses, strain XJ4T represents a novel species of the genus Frigidibacter, for which the name Frigidibacter oleivorans sp. nov. is proposed. The type strain is XJ4T (=CGMCC 1.13778T=LMG 30952T).

Paracoccus alkanivorans sp. nov., isolated from a deep well with oil reservoir water.

A Gram-stain-negative, non-motile and ovoid bacterial strain, designated 4-2T, was isolated from oil-contaminated water which was collected from Xinjiang Province, north-west PR China. The 16S rRNA gene sequence analysis showed that strain 4-2T belonged to the genus Paracoccus. The species with highest similarity to strain 4-2T was Paracoccus saliphilus YIM 90738T (97.83 %), followed by 'Paracoccus siganidrum' M26 (97.83 %) and Paracoccus endophyticus SYSUP0003T (97.25 %). The average nucleotide identity values between 4-2T and three type strains were 84.69, 77.88 and 74.07 %, respectively. The genomic DNA G+C content of strain 4-2T was 61.4 mol%. Chemotaxonomical characteristic results showed that the respiratory quinone was ubiquinone Q-10 and the major fatty acids were summed feature 8 (C18 : 1 ω7c or C18 : 1 ω6c) and C19 : 0 cyclo ω8c. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, unidentified phospholipids, an unidentified aminolipid and an unidentified polar lipid. The predominant polyamines were putrescine, cadaverine and spermidine. On the basis of phenotypic, chemotaxonomic and phylogenetic inferences, strain 4-2T represents a novel species of the genus Paracoccus, for which the name Paracoccus alkanivorans sp. nov. is proposed. The type strain is 4-2T (=CGMCC 1.13669T=LMG 30882T).

Evidence for Phosphate Starvation of Rhizobia without Terminal Differentiation in Legume Nodules.

Phosphate homeostasis is tightly modulated in all organisms, including bacteria, which harbor both high- and low-affinity transporters acting under conditions of fluctuating phosphate levels. It was thought that nitrogen-fixing rhizobia, named bacteroids, inhabiting root nodules of legumes are not phosphate limited. Here, we show that the high-affinity phosphate transporter PstSCAB, rather than the low-affinity phosphate transporter Pit, is essential for effective nitrogen fixation of Sinorhizobium fredii in soybean nodules. Symbiotic and growth defects of the pst mutant can be effectively restored by knocking out PhoB, the transcriptional repressor of pit. The pst homologs of representative rhizobia were actively transcribed in bacteroids without terminal differentiation in nodules of diverse legumes (soybean, pigeonpea, cowpea, common bean, and Sophora flavescens) but exhibited a basal expression level in terminally differentiated bacteroids (alfalfa, pea, and peanut). Rhizobium leguminosarum bv. viciae Rlv3841 undergoes characteristic nonterminal and terminal differentiations in nodules of S. flavescens and pea, respectively. The pst mutant of Rlv3841 showed impaired adaptation to the nodule environment of S. flavescens but was indistinguishable from the wild-type strain in pea nodules. Taken together, root nodule rhizobia can be either phosphate limited or nonlimited regarding the rhizobial differentiation fate, which is a host-dependent feature.

Nonspecific Symbiosis Between Sophora flavescens and Different Rhizobia.

We explored the genetic basis of the promiscuous symbiosis of Sophora flavescens with diverse rhizobia. To determine the impact of Nod factors (NFs) on the symbiosis of S. flavescens, nodulation-related gene mutants of representative rhizobial strains were generated. Strains with mutations in common nodulation genes (nodC, nodM, and nodE) failed to nodulate S. flavescens, indicating that the promiscuous nodulation of this plant is strictly dependent on the basic NF structure. Mutations of the NF decoration genes nodH, nodS, nodZ, and noeI did not affect the nodulation of S. flavescens, but these mutations affected the nitrogen-fixation efficiency of nodules. Wild-type Bradyrhizobium diazoefficiens USDA110 cannot nodulate S. flavescens, but we obtained 14 Tn5 mutants of B. diazoefficiens that nodulated S. flavescens. This suggested that the mutations had disrupted a negative regulator that prevents nodulation of S. flavescens, leading to nonspecific nodulation. For Ensifer fredii CCBAU 45436 mutants, the minimal NF structure was sufficient for nodulation of soybean and S. flavescens. In summary, the mechanism of promiscuous symbiosis of S. flavescens with rhizobia might be related to its nonspecific recognition of NF structures, and the host specificity of rhizobia may also be controlled by currently unknown nodulation-related genes.

The experimental study of shunt-decompression arterialized vein flap.

BACKGROUND: Arterialized vein flap is a kind of unphysiological flap. Unphysiological reconstruction of blood circulation leads to higher load than that supported by physiological flap and is the culprit of flap swelling, blood stasis, skin blistering, and necrosis after flap grafting. To resolve the multiple disadvantages of traditional flap grafting, by introducing the principles of fluid mechanics, shunt-decompression surgery is prepared to decline the circulation preload and improve the prognosis of arterialized vein flap grafting. METHODS: By introducing the principles of fluid mechanics, we established the model of shunt-decompression arterialized vein flap, which satisfied the common properties of general fluid that the interface pressure between object and fluid is reduced when the velocity of fluid is increased and vice versa-the effect of Bernoulli. Under this rule, we anastomose the arterialized vein to the branch of main artery of recipient region or make end-to-side anastomosis, which can maintain the blood flow of main artery, decrease the perfusion of flap, and preserve the decompressive effect of main artery to branches. From March, 2016 to September, 2016, we performed animal experiments on ten male bama mini pigs with average weight of 28 ± 2.35 kg. Superior epigastric artery of pig was used for feeding artery to arterialize the superficial epigastric veins. The total area of flap is 8 cm × 6 cm. End-to-side anastomosis and end-to-end anastomosis were established in experimental group and control group, respectively. Doppler speckle perfusion imaging apparatus was used to monitor the alterations of flap perfusion, blood flow of flap, tissue swelling and survival of flaps. RESULTS: The average flap perfusion (PU) at 1 week after surgery is 83.62 ± 3.14 in experimental group and 98.14 ± 6.54 in control group, respectively (P < 0.05), indicating the significant reduction of flap blood perfusion in experimental group as compared with control group. As to the survival of flaps, 7 flaps completely survived, 3 showed partial necrosis, and no one was found as complete necrosis in experimental group, while only 3 flaps survived, and 4 flaps and 3 flaps showed partial necrosis and complete necrosis in control group, respectively (P < 0.05). CONCLUSION: Based on the physiological features of arterialized vein flap and its problems in clinical application, we improved the anastomosis strategy of flap grafting and obtained excellent experimental outcomes, which provides an insight for the clinical application of arterialized vein flaps.

Sphingomonas oleivorans sp. nov., isolated from oil-contaminated soil.

Strain FW-11T was isolated from oil-contaminated soil from Panjin in Liaoning, China. It was a Gram-stain-negative, aerobic and rod-shaped bacterium. The strain was confirmed to be a member of the genus Sphingomonas based on phylogenetic inference and phenotypic characteristics. The best growth of strain FW-11T occurred at 30 °C and pH 6.0-7.0. The strain was non-spore-forming, catalase-negative and oxidase-negative. The main polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and unidentified lipids. The cell-wall peptidoglycan of strain FW-11T included alanine, glycine, glutamic acid, aspartic acid and meso-diaminopimelate. The predominant isoprenoid quinones were ubiquinone Q-10 (93.2 %) and Q-9 (6.8 %). The fatty acid profile (>5 %) included C18 : 1ω6c (43.1 %), C16 : 0 (14.6 %), C17 : 1ω6c (14.0 %) and C14 : 0 2-OH (11.1 %). The most similar neighbours of FW-11T were Sphingomonas fennica K101T (97.4 %) and Sphingomonas haloaromaticamans A175T (97.0 %). The average nucleotide identity relatedness values between strain FW-11T and the two type strains (S. fennica K101T and S. haloaromaticamans A175T) were 73.2 and 75.3 %, respectively. The genome size of FW-11T was 3.8 Mbp, comprising 3735 predicted genes with a DNA G+C content of 64.0 mol%. Based on phenotypic, chemotaxonomic and phylogenetic data, strain FW-11T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas oleivorans sp. nov. is proposed. The type strain is FW-11T (=LMG 29274T=HAMBI 3659T).

Drosophila Nipped-B Mutants Model Cornelia de Lange Syndrome in Growth and Behavior.

Individuals with Cornelia de Lange Syndrome (CdLS) display diverse developmental deficits, including slow growth, multiple limb and organ abnormalities, and intellectual disabilities. Severely-affected individuals most often have dominant loss-of-function mutations in the Nipped-B-Like (NIPBL) gene, and milder cases often have missense or in-frame deletion mutations in genes encoding subunits of the cohesin complex. Cohesin mediates sister chromatid cohesion to facilitate accurate chromosome segregation, and NIPBL is required for cohesin to bind to chromosomes. Individuals with CdLS, however, do not display overt cohesion or segregation defects. Rather, studies in human cells and model organisms indicate that modest decreases in NIPBL and cohesin activity alter the transcription of many genes that regulate growth and development. Sister chromatid cohesion factors, including the Nipped-B ortholog of NIPBL, are also critical for gene expression and development in Drosophila melanogaster. Here we describe how a modest reduction in Nipped-B activity alters growth and neurological function in Drosophila. These studies reveal that Nipped-B heterozygous mutant Drosophila show reduced growth, learning, and memory, and altered circadian rhythms. Importantly, the growth deficits are not caused by changes in systemic growth controls, but reductions in cell number and size attributable in part to reduced expression of myc (diminutive) and other growth control genes. The learning, memory and circadian deficits are accompanied by morphological abnormalities in brain structure. These studies confirm that Drosophila Nipped-B mutants provide a useful model for understanding CdLS, and provide new insights into the origins of birth defects.

Agrobacterium deltaense sp. nov., an endophytic bacteria isolated from nodule of Sesbania cannabina.

A Gram-negative, non-spore-forming, aerobic rods, strain YIC4121T, was isolated from root nodule of Sesbania cannabina grown in Dongying (Yellow River Delta), Shandong Province, PR China. Based on phylogenetic analysis of 16 S rRNA gene sequences, strain YIC4121T was assigned to the genus Agrobacterium with 99.7, 99.3, 99.0, 98.8 and 98.7% sequence similarities to Agrobacterium radiobacter LMG140T, A. pusense NRCPB10T, A. arsenijevicii KFB 330T, A. nepotum 39/7T and A. larrymoorei ATCC51759T. Analysis of the concatenated housekeeping genes (recA-atpD-glnII), showed lower sequence similarities (≤94.6%) between strain YIC4121T and other recognized Agrobacterium species. Strain YIC4121T shared whole-genome average nucleotide identities (ANI) 87.94, 91.27 and 77.42%, with A. pusense NRCPB10T, A. radiobacter LMG140T and A. larrymoorei ATCC51759T. The predominant cellular fatty acids were C19:0 cyclo ω8c, summed feature 2 (C12:0 aldehyde/unknown 10.9525), summed feature 8 (C18:1 ω7c/C18:1 ω6c), C16:0 3 OH and C16:0. The G + C content of strain YIC4121T was 59.80 mol%. Tween 80, lactulose, citric acid, α-ketoglutaric acid, glycyl-L-glutamic acid and 2, 3-butanediol could not be utilized as carbon source, distinguishing strain YIC4121T from the other related species. Based on the distinctly genetic and phenotypic dissimilarity, a novel species Agrobacterium deltaense sp. nov. is proposed with YIC4121T (=HAMBI 3654T = LMG 29283T) as the type strain.

Rhizobium hidalgonense sp. nov., a nodule endophytic bacterium of Phaseolus vulgaris in acid soil.

One Gram-negative, aerobic, motile, rod-shaped bacterium, designated as FH14T, was isolated from nodules of Phaseolus vulgaris grown in Hidalgo State of Mexico. Results based upon 16S rRNA gene (≥99.8 % similarities to known species), concatenated sequence (recA, atpD and glnII) analysis of three housekeeping genes (≤93.4 % similarities to known species) and average nucleotide identity (ANI) values of genome sequence (ranged from 87.6 to 90.0 % to related species) indicated the distinct position of strain FH14T within the genus Rhizobium. In analyses of symbiotic genes, only nitrogen fixation gene nifH was amplified that had nucleotide sequence identical to those of the bean-nodulating strains in R. phaseoli and R. vallis, while nodulation gene nodC gene was not amplified. The failure of nodulation to its original host P. vulgaris and other legumes evidenced the loss of its nodulation capability. Strain FH14T contained summed feature 8 (C18:1 ω6c/C18:1 ω7c, 59.96 %), C16:0 (10.6 %) and summed feature 2 (C12:0 aldehyde/unknown 10.928, 10.24 %) as the major components of cellular fatty acids. Failure to utilize alaninamide, and utilizing L-alanine, L-asparagine and γ-amino butyric acid as carbon source, distinguished the strain FH14T from the type strains for the related species. The genome size and DNA G+C content of FH14T were 6.94 Mbp and 60.8 mol %, respectively. Based on those results, a novel specie in Rhizobium, named Rhizobium hidalgonense sp. nov., was proposed, with FH14T (=HAMBI 3636T = LMG 29288T) as the type strain.

Agrobacterium salinitolerans sp. nov., a saline-alkaline-tolerant bacterium isolated from root nodule of Sesbania cannabina.

Two Gram-staining-negative, aerobic bacteria (YIC 5082T and YIC4104) isolated from root nodules of Sesbania cannabina grown in a high-salt and alkaline environment were identified as a group in the genus Agrobacterium because they shared 100 and 99.7 % sequence similarities of 16S rRNA and recA+atpD genes, respectively. These two strains showed 99.2/100 % and 93.9/95.4 % 16S rRNA and recA+atpD gene sequence similarities to Agrobacterium radiobacter LMG140T and Agrobacterium. pusense NRCPB10T, respectively. The average nucleotide identities (ANI) of genome sequences were 89.95 % or lower between YIC 5082T and the species of the genus Agrobacterium examined. Moreover, these two test strains formed a unique nifH lineage deeply separated from other rhizobia. Although the nodC gene was not detected in YIC 5082T and YIC4104, they could form effective root nodules on S. cannabina plants. The main cellular fatty acids in YIC 5082T were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c), C19 : 0cyclo ω8c, summed feature 2 (C12 : 0 aldehyde/unknown equivalent chain length 10.9525) and C16 : 0. The DNA G+C content of YIC 5082T was 59.3 mol%. The failure to utilize d-sorbitol as a carbon source distinguished YIC 5082T from the type strains of related species. YIC 5082T could grow in presence of 5.0 % (w/v) NaCl and at a pH of up to 10.0. Based on results regarding the genetic and phenotypic properties of YIC 5082T and YIC4104 the name Agrobacterium salinitolerans sp. nov. is proposed and YIC 5082T (=HAMBI 3646T=LMG 29287T) is designed as the type strain.

Day-night cycles and the sleep-promoting factor, Sleepless, affect stem cell activity in the Drosophila testis.

Adult stem cells maintain tissue integrity and function by renewing cellular content of the organism through regulated mitotic divisions. Previous studies showed that stem cell activity is affected by local, systemic, and environmental cues. Here, we explore a role of environmental day-night cycles in modulating cell cycle progression in populations of adult stem cells. Using a classic stem cell system, the Drosophila spermatogonial stem cell niche, we reveal daily rhythms in division frequencies of germ-line and somatic stem cells that act cooperatively to produce male gametes. We also examine whether behavioral sleep-wake cycles, which are driven by the environmental day-night cycles, regulate stem cell function. We find that flies lacking the sleep-promoting factor Sleepless, which maintains normal sleep in Drosophila, have increased germ-line stem cell (GSC) division rates, and this effect is mediated, in part, through a GABAergic signaling pathway. We suggest that alterations in sleep can influence the daily dynamics of GSC divisions.

Independent Effects of γ-Aminobutyric Acid Transaminase (GABAT) on Metabolic and Sleep Homeostasis.

Breakdown of the major sleep-promoting neurotransmitter, γ-aminobutyric acid (GABA), in the GABA shunt generates catabolites that may enter the tricarboxylic acid cycle, but it is unknown whether catabolic by-products of the GABA shunt actually support metabolic homeostasis. In Drosophila, the loss of the specific enzyme that degrades GABA, GABA transaminase (GABAT), increases sleep, and we show here that it also affects metabolism such that flies lacking GABAT fail to survive on carbohydrate media. Expression of GABAT in neurons or glia rescues this phenotype, indicating a general metabolic function for this enzyme in the brain. As GABA degradation produces two catabolic products, glutamate and succinic semialdehyde, we sought to determine which was responsible for the metabolic phenotype. Through genetic and pharmacological experiments, we determined that glutamate, rather than succinic semialdehyde, accounts for the metabolic phenotype of gabat mutants. This is supported by biochemical measurements of catabolites in wild-type and mutant animals. Using in vitro labeling assays, we found that inhibition of GABAT affects energetic pathways. Interestingly, we also observed that gaba mutants display a general disruption in bioenergetics as measured by altered levels of tricarboxylic acid cycle intermediates, NAD(+)/NADH, and ATP levels. Finally, we report that the effects of GABAT on sleep do not depend upon glutamate, indicating that GABAT regulates metabolic and sleep homeostasis through independent mechanisms. These data indicate a role of the GABA shunt in the development of metabolic risk and suggest that neurological disorders caused by altered glutamate or GABA may be associated with metabolic disruption.

Cultivable endophytic bacteria from heavy metal(loid)-tolerant plants.

To evaluate the interactions among endophytes, plants and heavy metal/arsenic contamination, root endophytic bacteria of Prosopis laevigata (Humb and Bonpl. ex Willd) and Sphaeralcea angustifolia grown in a heavy metal(loid)-contaminated zone in San Luis Potosi, Mexico, were isolated and characterized. Greater abundance and species richness were found in Prosopis than in Sphaeralcea and in the nutrient Pb-Zn-rich hill than in the poor nutrient and As-Cu-rich mine tailing. The 25 species identified among the 60 isolates formed three groups in the correspondence analysis, relating to Prosopis/hill (11 species), Prosopis/mine tailing (4 species) and Sphaeralcea/hill (4 species), with six species ungrouped. Most of the isolates showed high or extremely high resistance to arsenic, such as ≥100 mM for As(V) and ≥20 mM for As(III), in mineral medium. These results demonstrated that the abundance and community composition of root endophytic bacteria were strongly affected by the concentration and type of the heavy metals and metalloids (arsenic), as well as the plant species.