Analysis of movement in primary maize roots

Studying plant root kinematics is important for understanding certain aspects of root growth and movement, which are strictly correlated in plants. However, there is little available data on autonomous movements in plant roots, such as nutations, and the data that are available are poorly described. We investigated the autonomous movements during growth in primary maize roots by estimating the main kinematic parameters of nutations (i.e., the period of duration and amplitude) and the growth rate. The estimations of nutation parameters were performed by developing dedicated methods, which are based on the analysis of root tip displacement and tip velocity. The data relative to the tip displacements were obtained using tip tracing software developed by our team specifically for this purpose. The results confirmed that the nutational phenomenon covers the continuous range of periods and amplitudes, with certain dominant period-amplitude types, which we clustered into three groups: i) amplitudes less than 0.1 mm and 4–16 min periods, ii) amplitudes less than 0.1 mm and 20–120 min periods, and iii) amplitudes greater than 0.1 mm and 24–120 min periods.     

Influence of drying on the secondary structure of intrinsically disordered and globular proteins

Circular dichroism (CD) spectroscopy of five Arabidopsis late embryogenesis abundant (LEA) proteins constituting the plant specific families LEA_5 and LEA_6 showed that they are intrinsically disordered in solution and partially fold during drying. Structural predictions were comparable to these results for hydrated LEA_6, but not for LEA_5 proteins. FTIR spectroscopy showed that verbascose, but not sucrose, strongly affected the structure of the dry proteins. The four investigated globular proteins were only mildly affected by drying in the absence, but strongly in the presence of sugars. These data highlight the larger structural flexibility of disordered compared to globular proteins and the impact of sugars on the structure of both disordered and globular proteins during drying.     

Gap junctions in sea anemone, Nematostella vectensis, embryo

Gap junctions (GJs) are composed of membrane proteins that form channels connecting the cytoplasm of adjacent cells and permeable to ions and small molecules. They are considered to be the main or only type of intercellular channels and a universal feature of all multicellular animals (Metazoa). Till recently, sea anemones and corals (Anthozoa, Cnidaria) appeared to be an exception from this rule. There were no structural or physiological data supporting the presence of GJ in Anthozoa. For some time no genes homologous to GJ proteins (connexins or pannexins) were detected in sea anemone Nematostella vectensis (Cnidaria, Anthozoa) or other Anthozoa genomes. Recently, pannexin homolog was found in Nematostella. Our intracellular recordings demonstrate electrical coupling between blastomeres in embryos at the 8-cells stage. At the same time, carboxyfluorescein fluorescent dye did not diffuse between electrically coupled cells, which excludes the possibility that the observed electrical coupling is mediated by incomplete cytoplasm separation during the cleavage. These data support the idea that GJ are ubiquitous for Metazoa, and pannexins are universal GJ proteins.     

The effect of melatonin on the antioxidant status of rats with type II diabetes mellitus

The effect of melatonin on the intensity of free radical processes and activities of superoxide dismutase (SOD, EC 1.15.1.1.) and catalase (EC 1.11.1.6) has been investigated in liver and blood serum of rats with type II diabetes mellitus. According to results of this study the development of diabetes was accompanied by the increase in biochemiluminescence parameters and the enzyme activities studied. Melatonin administration changed the parameters studied towards control values and this is obviously associated with realization of the antioxidant potential of this hormone.     

Efficient and specific rescue of human immunodeficiency virus type 1 budding defects by a Nedd4-like ubiquitin ligase

To exit infected cells, human immunodeficiency virus type 1 (HIV-1) exploits the vacuolar protein-sorting pathway by engaging Tsg101 and ALIX through PTAP and LYPx(n)L late assembly (L) domains. In contrast, less-complex retroviruses often use PPxY L domains to recruit Nedd4 family ubiquitin ligases. Although HIV-1 Gag lacks PPxY motifs, we now show that the budding of various HIV-1 L-domain mutants is dramatically enhanced by ectopic Nedd4-2s, a native isoform with a truncated C2 domain. The effect of Nedd4-2s on HIV-1 budding required a catalytically active HECT domain and was specific, since other Nedd4 family proteins showed little activity and an unrelated retrovirus was not rescued. The residual C2 domain of Nedd4-2s was critical for the enhancement of HIV-1 budding and for the association of Nedd4-2s with Gag, as reflected by its incorporation into virus-like particles. Interestingly, the incorporation of Nedd4-2s also depended on its active site, indicating that the ability to form a thioester with ubiquitin was required. These data suggest a novel mechanism by which HIV-1 Gag can connect to cellular budding machinery.     

Relationships between the hippocampus and medial septal region and their alterations during epileptogenesis

EEGs of the hippocampus and the medial septal region (MSR) in the control conditions and during repeated stimulation of the perforant path were simultaneously recorded in awake guinea pigs. Changes in correlation of activity of these structures during seizures provoked by the stimulation (model of acute epilepsy) and in the process of epileptogenesis induced by the kindling (model of chronic epilepsy) were analyzed. A high correlation of the baseline activities of the hippocampus and MSR observed in the control sharply decreased during acute and chronic seizures. Kindling led to emergence of the MSR capability of hippocampus-independent generation of the field seizure discharges. In the process of kindling the progressive disintegration of activities of the hippocampus and the MSR was revealed being indicative of disorders in functioning of the septohippocampal network during epileptogenesis.     

Genetic structure of hereditary catalepsy in mice

Catalepsy or pronounced freezing is a natural passive defense strategy in animals and a syndrome of some mental disorders in human. Hereditary catalepsy was shown to be associated with depressive-like features in rats and mice. The loci underlying the difference in predisposition to catalepsy between catalepsy-prone CBA/lacJ and catalepsy-resistant AKR/J mice were mapped using congenic line and selective breeding approaches. Three congenic mouse lines (AKR.CBA-D13Mit76C, AKR.CBA-D13Mit76A and AKR.CBA-D13Mit78) carrying the 59- to 70-, 61- to 70- and 71- to 75-c m fragments of chromosome 13 transferred from the CBA to the AKR genome were created by nine successive backcrossing of (CBA × AKR)F₁ on AKR strain. Because catalepsy was found only in the AKR.CBA-D13Mit76C and AKR.CBA-D13Mit76A mice, the major gene of catalepsy was mapped on the fragment of 61–70 c m . Selective breeding of the (CBA × (CBA × AKR))BC backcross generation for high predisposition to catalepsy showed numerous genome-wide distributed CBA-derived alleles as well as the AKR-derived alleles mapped on chromosome 17 and on the proximal parts of chromosomes 10 and 19 that increased the cataleptogenic effect of the major gene.