Transformation Series as an Ideographic Character Concept

An ideographic concept of character is indispensable to phylogenetic inference. Hennig proposed that characters be conceptualized as “transformation series”, a proposal that is firmly grounded in evolutionary theory and consistent with the method of inferring transformation events as evidence of phylogenetic propinquity. Nevertheless, that concept is usually overlooked or rejected in favor of others based on similarity. Here we explicate Hennig's definition of character as an ideographic concept in the science of phylogenetic systematics. As transformation series, characters are historical individuals akin to species and clades. As such, the related concept of homology refers to a historical identity relation and is not equivalent to or synonymous with synapomorphy. The distinction between primary and secondary homology is dismissed on the grounds that it conflates the concept of homology with the discovery operations used to detect instances of that concept. Although concern for character dependence is generally valid, it is often misplaced, focusing on functional or developmental correlation (both of which are irrelevant in phylogenetic systematics but may be valid in other fields) instead of the historical/transformational independence relevant to phylogenetic inference. As an ideographic science concerned with concrete objects and events (i.e. individuals), intensionally and extensionally defined properties are inconsistent with the individuation of characters for phylogenetic analysis, the utility of properties being limited to communicating results and facilitating future rounds of testing.     

Synthesis of 2-chloro-2'-deoxyadenosine by microbiological transglycosylation using a recombinant Escherichia coli strain

Cladribine (2-chloro-2'-deoxyadenosine) was synthesized using intact cells of the recombinant Escherichia coli strain producing Geobacillus stearothermophilus B-2194 thermostable purine-nucleoside phosphorylase II (EC 2.4.2.1). Use of the cells containing this thermostable enzyme allowed the process to be conducted at a temperature of 70 degrees C, which provided the maximal concentrations of sparingly soluble substrates. The best results were obtained with 2-chloroadenine as a modified base. The highest yield of the target 2-chloro-2'-deoxyadenosine (up to 95% in the case of deoxyguanosine) was reached when using 2'-deoxypurines as donors of deoxyribose. Use of thymidine for these purposes required its considerable molar excess over 2-chloroadenine (up to 6 : 1), which is connected with a nonoptimal amount of endogenous thymidine phosphorylase, necessary for synthesis of deoxyribose-1-phosphate, in the transglycosylation reaction.     

The Biogenesis of the Photosynthetic Apparatus and the Activity of Chlorophyll Biosynthesis in a Plastome Mutant of Sunflower

It was demonstrated that, in the phenotypically colorless leaves of a sunflower (Helianthus annuusL.) plastome mutant with a heavily reduced level of chlorophyll, all pigment–protein complexes of the photosynthetic apparatus typical for the wild type were present. However, the ratio between them was changed. During aging of the mutant leaves, pigment–protein complexes of photosystem I were destroyed first followed by those of photosystem II. Chlorophyll a/b-containing light-harvesting complex II turned out to be the most stable. This conforms to an increased content of lutein and violaxanthin in mutant leaves. A synchrony of the decreases in the chlorophyll and 5-aminolevulinic acid (ALA) contents throughout all ontogenetic stages of the colorless mutant leaves made it possible to suggest that a decrease in the synthesis and resynthesis of chlorophyll during the formation and development of such leaves is caused by the inhibition of an initial stage of this process, namely, the biosynthesis of ALA molecules. The activity of the enzymes converting ALA into protochlorophyllide did not limit chlorophyll biosynthesis. Possible mechanisms controlling the synthesis of ALA destined for chlorophyll formation are discussed.     

Biotechnological synthesis of ribavirin. Effect of ribavirin and its various combinations on the reproduction of Vaccinia virus

The biotechnological method of synthesis of ribavirin, vidarabin, and 6-azauridine by the use of immobilized recombinant enzymatic preparations of nucleoside phosphorylase was improved. The effect of ribavirin and its combinations with the other synthesized nucleosides on the reproduction of Vaccinia virus was studied using cultures of Vero cells. The combination of ribavirin and vidarabin was shown to provide an antiviral effect at lesser concentrations than when these compounds were taken separately. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.     

Genetics of resistance to anthracnose and identification of AFLP and RAPD markers linked to the resistance gene in PI 320937 germplasm of lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> Medikus)

Anthracnose, caused by Colletotrichum truncatum, is a major disease problem and production constraint of lentil in North America. The research was conducted to examine the resistance to anthracnose in PI 320937 lentil and to identify molecular markers linked to the resistance gene in a recombinant inbred line (RIL) population developed from a cross of Eston lentil, the susceptible parent, and PI 320937, the resistant parent. A total of 147 F(5:6) RILs were evaluated for resistance to anthracnose in the greenhouse using isolate 95B36 of C. truncatum. Bulked segregant analysis (BSA) strategy was employed and two contrasting DNA bulks were constructed based on greenhouse inoculation of F(5)-derived F(6) RILs. DNA from the parents and bulks were screened with 700 RAPD primers and seven AFLP primer combinations. Analysis of segregation data indicated that a major dominant gene was responsible for resistance to anthracnose while variations in the resistance level among RILs could be the influences of minor genes. We designate the major gene as LCt-2. MapMaker analysis produced two flanking RAPD markers OPEO6(1250) and UBC-704(700) linked to LCt-2 locus in repulsion (6.4 cM) and in coupling (10.5 cM), respectively. Also, three AFLP markers, EMCTTACA(350) and EMCTTAGG(375) in coupling, and EMCTAAAG(175) in repulsion, were linked to the LCt-2 locus. These markers could be used to tag the LCt-2 locus and facilitate marker-assisted selection for resistance to anthracnose in segregating populations of lentil in which PI 320937 was used as the source of resistance. Also, a broader application of the linked RAPD markers was also demonstrated in Indianhead lentil, widely used as a source of resistance to anthracnose in the breeding program at the Crop Development Centre, University of Saskatchewan. Further selection within the few F(5:6) lines should be effective in pyramiding one or several of the minor genes into the working germplasm of lentil, resulting in a more durable and higher level of resistance.     

Synthesis and antibacterial activity of analogues of the N-terminal fragment of the sarcotoxin IA antimicrobial peptide

Three 18-membered analogues of the N-terminal fragment of the sarcotoxin IA cationic antimicrobial peptide were synthesized by the solid phase method of peptide synthesis with the use of swellographic monitoring. The ability of these peptides to inhibit the growth of various bacteria in culture medium and their hemolytic activity in experiments on human erythrocytes were studied. The analogue completely corresponding to the N-terminal amino acid sequence of the natural sarcotoxin IA with the amide group on its C-terminus exhibited higher antibacterial activity. The presence of carboxyl group on the C-terminus or the substitution of Tyr for Trp2 resulted in a decrease in the antimicrobial activity of the peptide. Our results indicate that the amphiphilic N-terminal peptide corresponding to the 1-18 sequence of sarcotoxin IA involves the moieties responsible for the antimicrobial activity of the antibiotic.     

Phylogeny of Riama (Squamata: Gymnophthalmidae), impact of phenotypic evidence on molecular datasets,and the origin of the Sierra Nevada de Santa Marta endemic fauna

Riama is the most speciose genus of the Neotropical lizard family Gymnophthalmidae. Its more than 30 montane species occur throughout the northern Andes, the Cordillera de la Costa (CC) in Venezuela, and Trinidad. We present the most comprehensive phylogenetic analysis of Riama to date based on a total evidence (TE) approach and direct optimization of molecular and morphological evidence. Analyses use DNA sequences from four loci and 35 phenotypic characters. The dataset consists of 55 ingroup terminals representing 25 of the 30 currently recognized species of Riama plus five undescribed taxa, including an endemic species from the Sierra Nevada de Santa Marta (SNSM) in Colombia, and 66 outgroup terminals of 47 species. Analysis results in a well‐supported hypothesis in which Riama is polyphyletic, with its species falling into three clades. The Tepuian Anadia mcdiarmidi nests within one clade of Riama, and the recently resurrected Pantodactylus nests within Cercosaura. Accordingly, we propose a monophyletic taxonomy that reflects historical relationships. Analysis of character evolution indicates that the presence/absence of prefrontals—a cornerstone of the early genus‐level taxonomy of cercosaurines—is optimally explained as having been plesiomorphically present in the most recent common ancestor of Cercosaurinae and lost in that of the immediately less inclusive clade. Multiple independent reversals to present and subsequent returns to absent occur within this clade. To evaluate the impact of phenotypic evidence on our results, we compare our TE results with results obtained from analyses using only molecular data. Although phenotypic evidence comprises only 1.2% of the TE matrix, its inclusion alters both the topology and support values of the clades that do not differ. Finally, current phylogenetic evidence reveals a SNSM–CC–Trinidad–tepuis biogeographical link. We hypothesize that an ancient connection facilitated the exchange of species between the SNSM and the CC.     

Unit responses of the secondary somatosensory cortex during defensive conditioning in cats

Unit responses in the secondary somatosensory cortex during the formation and extinction of a defensive conditioned reflex to acoustic stimulation were investigated in chronic experiments on cats. In 21 of 28 neurons tested during defensive conditioning the firing pattern changed in accordance with the character of responses to electric shock reinforcement. Two types of conditioned-reflex unit responses were distinguished: excitatory and inhibitory. Most neurons responding to the conditioned stimulus by activation did so during the first 50 msec, which was 80–100 msec before the conditioned motor response. Considerable variability of the unit responses was observed during conditioning. By the time of stabilization of the conditioned-reflex connections the unit response to the conditioned stimulus was stable in form. The pattern of extinction of the conditioned unit activity was expressed as a decrease in the discharge frequency in responses of excitatory type and disinhibition of activity in the case of inhibitory responses.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev, Translated from Neirofiziologiya, Vol. 9, No. 3, pp. 232–238, May–June, 1977.     

Responses of secondary sensomotor cortical neurons to electrodermal and acoustic stimulation in waking cats

Unit responses in the second somatosensory cortical projection area (SII) to clicks and electric shocks applied to the contralateral limb were investigated in chronic experiments on cats. In response to specific stimulation for the cortical region studied the discharge frequency of 75% of neurons increased, spontaneous activity of 18% was reduced in frequency or the discharges ceased altogether, and 25% of cells did not respond. In response to "nonspecific" stimulation (clicks) 30% of neurons were activated; the discharge of 25% of cells was inhibited and 45% did not respond. The results of investigation of intersensory convergence of stimuli from different sensory systems showed that a high proportion (55%) of SII neurons give bimodal responses. Another 18% of neurons give a specific response to both adequate and inadequate stimulation. It is suggested that the presence of polysensory convergence of SII neurons and of short pathways for the conduction of sensory information, and also the ability of neurons to acquire polysensory properties during stimulus presentation are evidence of the important role of this cortical region in conditioning.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 9, No. 5, pp. 453–459, September–October, 1977.