Diagnostic polymorphisms in the mitochondrial cytochrome b gene allow discrimination between cattle,sheep, goat,roe buck and deer by PCR-RFLP

Background  

As an alternative to direct DNA sequencing of PCR products, random PCR-RFLP is an efficient technique to discriminate between species. The PCR-RFLP-method is an inexpensive tool in forensic science, even if the template is degraded or contains only traces of DNA from various species.     

Charging of submicron structures during silicon dioxide etching in one- and two-frequency gas discharges

A model that combines the Monte Carlo method for calculating electron and ion trajectories in three-dimensional geometry and an analytic approach developed for calculating an electric field in two-dimensional geometry is used to simulate the charging of the surface of periodic submicron SiO₂ structures by electron and ion fluxes in the plasma of a one- and a two-frequency capacitive RF discharge. The energy distribution function of the electrons and ions that come to the bottom of a submicron structure in an argon and an argon-containing plasma is calculated for structures with a width of 11–45 nm and an aspect ratio of d/w = 1–10 (where d and w are the depth and width of the structure). It is shown that secondary electronelectron emission plays an important role in the redistribution of the electric charge and, accordingly, of the electric potential in a submicron structure. It is demonstrated that, when the secondary electron-electron emission mechanism is taken into account, the ion energy spectrum at the bottom of a submicron structure is shifted toward lower energies and becomes broader in comparison with the spectrum of an ion flux from an RF discharge plasma. Moreover, the shift and broadening depend only on the secondary electron-electron emission coefficient, the energy of the charged particles, and the aspect ratio.     

“Bacillus thermoantarcticus” sp. nov., from Mount Melbourne,Antarctica: a novel thermophilic species

 A novel thermophilic Gram-positive bacillus, “Bacillus thermoantarcticus”, isolated from geothermal soil near the crater of Mount Melbourne, is described. The organism grows at an optimal temperature of 63^°C at pH 6.0, is oxidase-positive, catalase-negative and produces an exopolysaccharide, an exocellular xylanase, an intracellular alcohol dehydrogenase and exo- and endocellular α-glucosidase(s). The sequence of 16S rDNA is very similar to that of “Bacillus thermoglucosidasius”; however, the guanine-plus-cytosine (G+C) content is 8 mol% higher. The type strain is “Bacillus thermoantarcticus” (DSM 9572). Received : 3 February 1995/Accepted : 12 May 1995     

Bacterial Hen1 is a 3′ terminal RNA ribose 2′-O-methyltransferase component of a bacterial RNA repair cassette

Hen1 is an RNA ribose 2′-O-methyltransferase that modifies the 3′ terminal nucleoside of eukaryal small regulatory RNAs. Here, we report that Hen1 homologs are present in bacterial proteomes from eight different phyla. Bacterial Hen1 is encoded by the proximal ORF of a two-gene operon that also encodes polynucleotide kinase-phosphatase (Pnkp), an RNA repair enzyme. Purified recombinant Clostridium thermocellum Hen1 is a homodimer of a 465-amino acid polypeptide. CthHen1 catalyzes methyl transfer from AdoMet to the 3′ terminal nucleoside of an RNA oligonucleotide, but is unreactive with a synonymous DNA oligonucleotide or an RNA with a single 3′-terminal deoxyribose sugar. CthHen1 is optimally active at alkaline pH and dependent on manganese. Activity is inhibited by AdoHcy and abolished by mutations D291A and D316A in the putative AdoMet-binding pocket. The C-terminal fragment, Hen1-(259–465), comprises an autonomous monomeric methyltransferase domain.     

An atypical RNA pseudoknot stimulator and an upstream attenuation signal for -1 ribosomal frameshifting of SARS coronavirus

The −1 ribosomal frameshifting requires the existence of an in cis RNA slippery sequence and is promoted by a downstream stimulator RNA. An atypical RNA pseudoknot with an extra stem formed by complementary sequences within loop 2 of an H-type pseudoknot is characterized in the severe acute respiratory syndrome coronavirus (SARS CoV) genome. This pseudoknot can serve as an efficient stimulator for −1 frameshifting in vitro. Mutational analysis of the extra stem suggests frameshift efficiency can be modulated via manipulation of the secondary structure within the loop 2 of an infectious bronchitis virus-type pseudoknot. More importantly, an upstream RNA sequence separated by a linker 5′ to the slippery site is also identified to be capable of modulating the −1 frameshift efficiency. RNA sequence containing this attenuation element can downregulate −1 frameshifting promoted by an atypical pseudoknot of SARS CoV and two other pseudoknot stimulators. Furthermore, frameshift efficiency can be reduced to half in the presence of the attenuation signal in vivo. Therefore, this in cis RNA attenuator represents a novel negative determinant of general importance for the regulation of −1 frameshift efficiency, and is thus a potential antiviral target.     

Evidence that N-methyl-N′-nitro-N-nitrosoguanidine induces adaptive response in Bacillus thuringiensis

Bacillus thuringiensis is shown to have an inducible error-free repair system for alkylation damage as found in Escherichia coli and Bacillus subtilis. Growth of cells in the presence of low concentrations of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) induces an adaptive response which is characterized by an increase in resistance to killing and mutagenesis by challenge with higher concentrations of MNNG. In addition, we have noted with interest that adaptive low doses seem to produce lesions at a rate sufficient to induce an increase of mutation frequency, and inhibition of cell division. The possibility of an interaction between SOS and adaptive responses with these low doses of MNNG is discussed.     

Single species evolutionary dynamics

Not long after the introduction of evolutionary stable strategy (ESS) concept, it was noticed that dynamic selection did not always lead to the establishment of the ESS. The concept of continuously stable strategy (CSS) was thereafter developed. It was generally accepted that dynamic selection leads to the establishment of an ESS if it is a CSS. Examination of an evolutionary stability concept which is called neighborhood invader strategy (NIS) shows that it may be impossible for an ESS to be established through dynamic selection even if it is a CSS and no polymorphisms occur. We will examine the NIS concept and its implications for two evolutionary game models: root-shoot allocation in plant competition and Lotka–Volterra competition. In the root-shoot model we show that an ESS will be attained through dynamic selection if it is a NIS. Similarly for the Lotka–Volterra model, we show that an ESS will be attained through dynamic selection even if protected dimorphisms occur during the evolutionary process if it is an NIS.     

Long-lived Ar-Hg plasma in the afterglow of a high-current pulsed discharge

High-density (n > 10¹² cm^?3) argon-mercury plasma produced by a short (t ～ 20 μs) high-power pulsed discharge in argon with an admixture of mercury vapor at a discharge current of ～50 A, an argon pressure of ～4 mm Hg, and a mercury vapor pressure of ～10^?3 mm Hg was studied using optical spectroscopy and radio physics methods. It is found that the lifetime of this plasma after the end of the discharge pulse is up to 10^?2 s. It is shown that such an abnormally long lifetime of such an afterglow plasma, as compared to the plasma of an argon discharge without an admixture of mercury vapor, is related to the long residence time of atoms and ions of both argon and mercury in highly excited states due to chemi-ionization processes involving long-lived metastable argon ions. It is suggested that dissociative recombination of highly excited molecular ions of argon play an important role in the transfer of excitation to argon atoms and ions that are close to autoionization states.     

Regulation of Escherichia coli IscS desulfurase activity by ferrous iron and cysteine

IscS plays a principal role in the synthesis of sulfur-containing biomolecules. It is known that the expression of iscS can be negatively regulated by IscR, the first gene product of iscRSUA-hscBA-fdx. What governs the regulation of cysteine desulfurase activity, however, is unknown. Here, we report that IscS from Escherichia coli is able to bind iron with an association constant of 1.6 × 10¹⁷ M⁻¹ to form an IscS-iron complex. IscS is also capable of binding both iron and sulfide to form an IscS-iron-sulfide complex with a higher affinity. The desulfurase activity is gradually inhibited as the amount of iron and sulfide bound to IscS increases. When 2Fe-2S binds IscS, about 20% of the activity is inhibited; when 8Fe-8S adheres to IscS, about 70% of the activity is inhibited. Thus, the cell is able to modulate its desulfurase activity with the formation of an IscS-iron-sulfide complex.     

Distribution-free Estimation of a Monotonic pth Quantile Function

When analyzing biological data sets, a frequent problem is to estimate the pth quantile of a distribution, when that quantile is assumed to depend on a covariate; in the present paper the dependence of the quantile on the covariate is assumed to be monotonic. Some properties of an isotonic pth quantile regression, considered as an estimator of an increasing pth quantile function, are presented.     

Morphologische untersuchungen an zwei drüsentypen (Thoraxdrüse,Mandibeldrüse) von Lepidopterenraupen

Two types of possibly homologous glands different in structure and formation have been found. One of them is represented in C. vinula L. and N. anceps Goeze, it is an endocrine organ. The other in S. ligustri, S. ocellata, M. neustria and L. monacha has an excretory duct and therefore is an exocrine organ.

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Mit dankenswerter Unterstützung der Deutschen Forschungsgemeinschaft.     

Filamin repeat segments required for photosensory signalling in <Emphasis Type="Italic">Dictyostelium discoideum</Emphasis>

Background  

Filamin is an actin binding protein which is ubiquitous in eukaryotes and its basic structure is well conserved – an N-terminal actin binding domain followed by a series of repeated segments which vary in number in different organisms. D. discoideum is a well established model organism for the study of signalling pathways and the actin cytoskeleton and as such makes an excellent organism in which to study filamin. Ddfilamin plays a putative role as a scaffolding protein in a photosensory signalling pathway and this role is thought to be mediated by the unusual repeat segments in the rod domain.     

Identification and characterization of interferon regulatory factor-1 from orange-spotted grouper (<Emphasis Type="Italic">Epinephelus coioides</Emphasis>)

Interferon-regulatory factor 1 (IRF-1) is the first member of IRF family, which is involved in many biological processes such as immune response, antiviral defense, cell growth regulation, and apoptosis. In this study, an IRF-1 gene, EcIRF-1, was isolated and characterized from orange-spotted grouper (Epinephelus coioides). The full-length cDNA of EcIRF-1 is 1,730 bp, including an open reading frame of 906 bp, a 5′-terminal untranslated region (5′-UTR) of 153 bp, and a 3′-UTR of 671 bp. The EcIRF-1 gene consists of 10 exons and 9 introns, spanning over approximate 4.3 kb of genomic sequence. The 5′-UTR sequence contains an exon and an intron, and the 3′-UTR sequence is included in the last exon. Expression analysis by real-time PCR reveals that the EcIRF-1 gene is ubiquitously expressed in various healthy fish tissues, whereas its expression is upregulated in vivo in response to polyinosinic–polycytidylic acid or lipopolysaccharide stimulation. Subcellular localization analysis shows the EcIRF-1 is an intranuclearly localized and immobile protein in the cultured fish cells. Data presented in this paper provide an important base to further understand EcIRF-1 gene function and its regulation associated with interferon immune system in orange-spotted grouper.     

Truncus arteriosus: an autosomal recessive disease?

Truncus arteriosus is an uncommon heart malformation; it is not reported that recurrence is high; nevertheless authors report three families with two or more cases; in the third there is a very high consanguinity (two uncle-niece marriages). The authors compare the situation with hypoplastic left heart and think that some cases of truncus arteriosus would have an autosomal recessive inheritance. That is an another argument for suggesting an echocardiographic survey of the pregnancies in these families.     

Autophagosomes,phagosomes, autolysosomes,phagolysosomes, autophagolysosomes… Wait,I’m confused

When an autophagosome or an amphisome fuse with a lysosome, the resulting compartment is referred to as an autolysosome. Some people writing papers on the topic of autophagy use the terms “autolysosome” and “autophagolysosome” interchangeably. We contend that these words should be used to denote 2 different compartments, and that it is worthwhile maintaining this distinction—the autophagolysosome has a particular origin in the process of xenophagy that makes it distinct from an autolysosome.     

Ribonucleotide reductase: A structural study of the dimeric iron site

The iron-containing B2 subunit of ribonucleotide reductase from Escherichia coli has been investigated by Raman spectroscopy. Both the tyrosyl radical-containing native protein and the radical-free protein exhibit a resonance-enhanced Raman band at 500 cm^?1. This band is assigned to an Fe-O vibrational mode arising from an oxygen-containing ligand. The failure to observe any tyrosinate ring modes makes it unlikely that ribonucleotide reductase is an iron-tyrosinate protein and rules out tyrosinate oxygen as a ligand. It is proposed that the 500 cm^?1 band in ribonucleotide reductase is analogous to the 510 cm^?1 Fe-O vibrational mode of methemerythrin and arises from an oxo- or carboxylate-bridge between the antiferromagnetically-coupled Fe(III) ions.     

Reproductive suppression in female primates: A review

Reproductive performance is the currency of evolution. All things being equal, an organism should reproduce as often as possible. The puzzling questions in evolutionary biology, therefore, are not how and why an organism does reproduce, but rather how and why an organism does not reproduce. It is difficult to understand why any individual, particularly a female, might forestall reproduction when one of the biggest limitations for female mammalian reproduction is time (that is, reproductive lifespan). 1 The answer, now widely cited throughout behavioral ecology is quite simple: Reproductive suppression can be an adaptive strategy. 2     

Pyocyanin: production,applications, challenges and new insights

Pseudomonas aeruginosa is an opportunistic, Gram-negative bacterium and is one of the most commercially and biotechnologically valuable microorganisms. Strains of P. aeruginosa secrete a variety of redox-active phenazine compounds, the most well studied being pyocyanin. Pyocyanin is responsible for the blue-green colour characteristic of Pseudomonas spp. It is considered both as a virulence factor and a quorum sensing signalling molecule for P. aeruginosa. Pyocyanin is an electrochemically active metabolite, involved in a variety of significant biological activities including gene expression, maintaining fitness of bacterial cells and biofilm formation. It is also recognised as an electron shuttle for bacterial respiration and as an antibacterial and antifungal agent. This review summarises recent advances of pyocyanin production from P. aeruginosa with special attention to antagonistic property and bio-control activity. The review also covers the challenges and new insights into pyocyanin from P. aeruginosa.     

Determination of the mimic epitope of the M-like protein adhesin in swine <Emphasis Type="Italic">Streptococcus equi</Emphasis> subsp. <Emphasis Type="Italic">zooepidemicus</Emphasis>

Background  

The M-like protein, also known as SzP, is expressed on the surface of Streptococcus equi subsp. zooepidemicus (S. zooepidemicus). Previous studies demonstrated that SzP is similar to M protein of group A Streptococcus in the structure and characteristics of antiphagocytosis. The M protein is an adhesin that can bind to the host cells, however it is not known whether the SzP of S. zooepidemicus also functions as an adhesin. We conducted an investigation to determine SzP as an adhesin, and one SzP epitope was identified to be responsible for mediating binding to HEp-2 cells.