<Emphasis Type="Italic">A2144G</Emphasis> Is the Main Mutation in the <Emphasis Type="Italic">23S</Emphasis> rRNA Gene of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Associated with Clarithromycin Resistance

To detect point mutations A2115C, A2143G/C, and A2144G in the 23S rRNA gene of Helicobacter pylori associated with resistance of the microorganism to clarithromycin, a new powerful way of analysis was used. This method involved the reaction of minisequencing followed by MALDI-TOF mass spectrometry of reaction products. In ten analyzed clarithromycin-resistant clinical isolates of H. pylori obtained in Russia, the resistance was found to be mediated only by mutation A2144G in the 23S rRNA gene.     

An Examination of the Association between 5-HTTLPR,Combat Exposure,and PTSD Diagnosis among U.S. Veterans

Objective

To examine the association between the 5-HTTLPR polymorphism of the serotonin transporter (SLC6A4) gene, combat exposure, and posttraumatic stress disorder (PTSD) diagnosis and among two samples of combat-exposed veterans.

Method

The first sample included 550 non-Hispanic Black (NHB) combat-exposed veterans. The second sample included 555 non-Hispanic White (NHW) combat-exposed veterans. Participants were genotyped for the 5-HTTLPR/rs25531 variants of the SLC6A4 gene. A structured clinical interview was used to diagnose PTSD. Combat and civilian trauma exposure were assessed with validated self-report instruments. Logistic regression was used to test for main effects of 5-HTTLPR on PTSD diagnosis as well as gene x environment (GxE) interactions after adjusting for sex, ancestry proportion scores, civilian trauma exposure, and combat exposure.

Results

Within the NHB sample, a significant additive effect was observed for 5-HTTLPR (OR = 1.502, p = .0025), such that the odds of having a current diagnosis of PTSD increased by 1.502 for each additional S’ allele. No evidence for an association between 5-HTTLPR and PTSD was observed in the NHW sample. In addition, no evidence for combat x 5-HTTLPR effects were observed in either sample.

Conclusion

The present study suggests that there may be an association between 5-HTTLPR genotype and PTSD diagnosis among NHB veterans; however, no evidence for the hypothesized 5-HTTLPR x combat interaction was found.     

Large-scale and fine-grain population structure and genetic diversity of snow leopards (Panthera uncia Schreber, 1776) from the northern and western parts of the range with an emphasis on the Russian population

Conservation Genetics - The snow leopard (Panthera uncia Schreber, 1776) population in Russia and Mongolia is situated at the northern edge of the range, where instability of ecological conditions...     

Complete genome and proteome of Acholeplasma laidlawii

We present the complete genome sequence and proteogenomic map for Acholeplasma laidlawii PG-8A (class Mollicutes, order Acholeplasmatales, family Acholeplasmataceae). The genome of A. laidlawii is represented by a single 1,496,992-bp circular chromosome with an average G+C content of 31 mol%. This is the longest genome among the Mollicutes with a known nucleotide sequence. It contains genes of polymerase type I, SOS response, and signal transduction systems, as well as RNA regulatory elements, riboswitches, and T boxes. This demonstrates a significant capability for the regulation of gene expression and mutagenic response to stress. Acholeplasma laidlawii and phytoplasmas are the only Mollicutes known to use the universal genetic code, in which UGA is a stop codon. Within the Mollicutes group, only the sterol-nonrequiring Acholeplasma has the capacity to synthesize saturated fatty acids de novo. Proteomic data were used in the primary annotation of the genome, validating expression of many predicted proteins. We also detected posttranslational modifications of A. laidlawii proteins: phosphorylation and acylation. Seventy-four candidate phosphorylated proteins were found: 16 candidates are proteins unique to A. laidlawii, and 11 of them are surface-anchored or integral membrane proteins, which implies the presence of active signaling pathways. Among 20 acylated proteins, 14 contained palmitic chains, and six contained stearic chains. No residue of linoleic or oleic acid was observed. Acylated proteins were components of mainly sugar and inorganic ion transport systems and were surface-anchored proteins with unknown functions.     

Lipid fatty acid composition of potato plants transformed with the Δ12-desaturase gene from cyanobacterium

Potato (Solanum tuberosum L.) plants were transformed with the desA gene encoding Δ12 acyl-lipid desaturase in the cyanobacterium Synechocystis sp. PCC 6803. To evaluate the efficiency of this gene expression in the plant, its sequence was translationally fused with the sequence of the reporter gene encoding thermostable lichenase. A comparison of native and hybrid gene expression showed that lichenase retained its activity and thermostability within the hybrid protein, whereas desaturase retained its capability of inserting the double bond in fatty acid (FA) chains and, thus, to modify their composition in membrane lipids. In most transformed plants, shoots contained higher amounts of polyunsaturated FAs, linoleic and linolenic (by 39–73 and 12–41%, respectively). The total absolute content of unsaturated FAs was also higher in transformants by 20–42% as compared to wild-type plants. When transformed plants were severely cooled (to ?7°C), the rate of their membrane lipid peroxidation was not enhanced, whereas in wild-type plants, it increased substantially (by 25%) under such conditions. These results could indicate a higher tolerance of transformed plants to low temperatures and the oxidative stress induced by hypothermia.     

Sequential colonization by river periphyton analysed by microscopy and molecular fingerprinting

1. An artificial glass substratum was incubated in the River Danube for a period of 28 days in order to detect the sequential colonization of microorganisms.
2. Light and fluorescent microscopy showed that microalgae and the picoalgal fraction on the slides increased rapidly over the first 2 weeks of colonization. Diatoms were numerically the most abundant component of the periphyton and their species richness and diversity increased rapidly in the early phase of colonization whereas diversity subsequently increased moderately.
3. Evenness of the diatom community was initially high, lower in the intermediate phase and again higher later on. Succession involving early, intermediate and late colonizer species was observed. Community composition during the first 5 days of colonization was very different from later stages whereas there were only minor changes subsequently.
4. Molecular community analysis by means of terminal restriction fragment length polymorphism analysis of PCR amplified 16S rRNA and 18S rRNA genes pointed to even larger differences between the composition of samples obtained early and late in the period.
5. The number of 18S rRNA and 16S rRNA terminal restriction fragments (T-RF-s) was variable over the colonization period and the fragment patterns of both the bacterial and eukaryotic portion of the microbial community were variable, with most T-RF-s unique to a single sample, suggesting a wide diversity and dynamic properties of periphytic organisms.     

The Effect of Helminthosporic Root Rot on the Composition of Acyl Lipids of Wheat Seedlings

The changes of the molecular species composition of esterified fatty acids (FAs) of total and nonextractable lipids were determined in roots and etiolated shoots of 3- to 10-day-old wheat (Triticum aestivumL.) seedlings infected with the fungus Bipolaris sorokiniana, the agent of helminthosporic root rot. A novel technique of assessing the extent of the infection-induced deviation of FA composition, mol %, from the control value was developed. It consists in the quantitative determination of both the deviations in this composition and the extent of contribution of separate FA species to the deviations observed. The application of this technique has shown that, for the total lipids, the maximum of such a deviation, in accordance with the membrane theory of stress, directly coincided in time with the onset of a decrease in the dry matter content in both roots and shoots. In each of these, the deviation was primarily caused by the change in the content of those FA species that usually dominate in a specific group of membrane lipids prevailing in a given organ, viz., plastid glycolipids in shoots and extraplastidal membrane phospholipids in roots. In both cases, C₂₀–C₂₂FAs significantly contributed to the deviations observed. This fact seems to reflect an enhanced formation of epicuticular waxes rich in these FAs on the shoot and root surfaces as an adaptive response of plants to fungal infection. Nonextractable (annular) membrane lipids, because of their vital importance for the survival of plant cells, differed from the total lipids with a far greater stability of their quantitative FA composition under conditions of infection-induced metabolic disturbances.     

Isolation and Characteristic of Overlong-Chain Unsaturated Aldehydes from the Freshwater Sponge <Emphasis Type="Italic">Lubomirskia baicalensis</Emphasis>

Several unusual overlong-chain unsaturated aldehydes (22 : 1, 22 : 2, 23 : 1, 24 : 1, 24 : 2, and 25 : 2) were found in total lipids of the endemic sponge Lubomirskia baicalensis from Baikal Lake. Tetracos-17-enal was identified as the major aldehyde of the mixture using GC-MS and ¹H and ¹³C NMR spectroscopy. A procedure for the isolation of total overlong-chain aldehydes was suggested. We think that the overlong-chain aldehydes defend the sponge from fouling and predators.     

Identification of unusual fatty acids of four alpine plant species from the Pamirs

Fatty acid composition and structure in total lipids from the green above-ground parts of four alpine plants, Oxygraphis glacialis, Primula macrophylla, Rhodiola pamiroalaica, and Swertia marginata, were established by GC and GC-MS. A total of 55 fatty acids was detected, and 48 of them were identified. Ubiquitous palmitate, linoleate, and linolenate predominated in the lipids accounting for about 72-90% of the total fatty acids. At the same time, the latter contained numerous species, which were unusual for higher plants and included saturated odd-numbered n-acids (six C15-C25 species, 0.26-1.40%), saturated even-numbered very-long-chain n-acids (six C20-C30 species, 1.00-2.49%), iso-acids (nine C15-C26 species, 0.64-1.53%), anteiso-acids (four C15-C20 species, 0.08-1.57%), certain uncommon mono- and dienoic acids, as well as 16:3omega3, 18:3omega6, and 18:4omega3 acids that are absent from the most higher plants. Nine fatty acids were found here for the first time in higher plants and two may be new to science. The evidence on the unusual fatty acids is discussed with respect to their distribution in living organisms, pathways of biosynthesis, and chemotaxonomic role.