Potential of fructans as natural cryoprotectant agents in plant cryopreservation: concept validation on Arabidopsis thaliana L.

BACKGROUND: Today, synthetic chemicals are used in vitrification solutions for cryopreservation studies to mimic natural cryoprotectants that supply tolerance to organisms in nature against freezing stress. In the case of plants, PVS2, containing glycerol, dimethyl sulfoxide (Me2SO), ethylene glycol and sucrose, is considered as the golden standard for successful cryopreservation. However, Me2SO can generally cause toxicity to certain plant cells, adversely affecting viability after freezing and/or thawing. Hence, the replacement (or substantial reduction) of Me2SO by cheap, non-toxic and natural cryoprotectants became a matter of high priority to vitrification solutions or reducing their content gained escalating importance for the cryopreservation of plants. Fructans, sucrose derivatives mainly consisting of fructose residues, are candidate cryoprotectants. OBJECTIVE: Inspired by their protective role in nature, we here explored, for the first time, the potential of an array of 8 structurally different fructans as cryoprotectants in plant cryopreservation. MATERIALS AND METHODS: Arabidopsis thaliana L. seedlings were used as a model system with a one-step vitrification method. PVS2 solutions with different Me2SO and fructan contents were evaluated. RESULTS: It was found that branched low DP graminan, extracted from milky stage wheat kernels, led to the highest recovery (85%) among tested fructans with 12.5% Me2SO after cryopreservation, which was remarkably close to the viability (90%) observed with the original PVS2 containing 15% Me2SO. Moreover, its protective efficacy could be further optimized by addition of vitamin C acting as an antioxidant. CONCLUSION: Such novel formulations offer great perspectives for cryopreservation of various crop species. Doi.org/10.54680/fr24410110512.

Morphological and molecular descriptions of Sphaeromyxa sevastopoli (Cnidaria) from host fishes from Sinop on the Black Sea coast.

Members of the genus Sphaeromyxa Thélohan, 1892 have been reported from a wide variety of fish species worldwide. In the present study, specimens of rusty blenny, Parablennius sanguinolentus, collected from Sinop on the Turkish Black Sea coast were investigated for myxosporean parasites by using both conventional and molecular methods. Sphaeromyxa sevastopoli Naidenova 1970 was the only myxosporean parasite found in the gall bladder of host fishes. The morphology peculiarities of obtained S. sevastopoli spores are in good agreement with those of original description and the morphometric data overlapped in spore length and width but differed in polar capsule length and width; however, they were within the ranges previously reported from 18 host fish species. Moreover, in the present study, molecular analysis of the 18S rDNA gene of S. sevastopoli isolate in our P. sanguinolentus as well as isolates from shore rockling Gaidropsarus mediterraneus and knout goby Mesogobius batrachocephalus which were previously morphologically identified and reported by Okkay and Özer (Acta Zool Bulg 72(1):123-130, 2020) was done for the first time and our three S. sevastopoli genotypes were allocated to the "balbianii" group which is characterized by straight or slightly curved and fusiform or ovoid spores with ovoid polar capsules.

Morphology and molecular phylogeny of Ortholinea mullusi sp. nov. (Myxozoa) in Mullus barbatus from the Black Sea.

Myxosporeans of the genus Ortholinea have a worldwide distribution and infect organs and tissues of exclusively marine fishes. Here we describe the morphological and molecular characteristics of Ortholinea mullusi sp. nov. parasitizing the urinary bladder and kidney tubules of red mullet Mullus barbatus collected from the coastal zone of Sinop in the Black Sea, Turkey. Polysporic plasmodia with immature spores were either elongate, 37.0 ± 4.5 SD (30-50) µm long and 45.0 ± 3.8 (40-55) µm wide, or were round, up to 100.0 µm in diameter. Mature, free spores were spherical in the frontal view and measured 9.3 ± 0.2 (9.0-9.7) µm in length, 8.7 ± 0.3 (8.2-9.3) µm in width and 7.7 ± 0.1 (7.5-7.9) µm in thickness. We observed 2 polar capsules of equal size, which measured 3.1 ± 0.1 (3.0-3.2) µm long by 2.5 ± 0.1 (2.4-2.6) µm wide, and the tips of the polar capsules were open towards the sutural line. The prevalence of infection by O. mullusi sp. nov. was 24.5%. Phylogenetic analysis based on nuclear small subunit ribosomal DNA (SSU rDNA) clearly suggested O. mullusi to be a new species, clustered within a lineage comprising O. labracis and O auratae. Pairwise nucleotide similarities and DNA distance values between O. mullusi sp. nov. and sister Ortholinea species also supported this suggestion.

Two novel myxosporean parasites in Black Sea fishes: Kudoa niluferi sp. nov. and Kudoa anatolica sp. nov. (Cnidaria: Myxosporea).

Members of the genus Kudoa are typically histozoic and only a few are coelozoic parasites, mainly in marine fishes. In the present study, 2 novel Kudoa species were recovered and described as Kudoa niluferi sp. nov. in the musculature of Neogobius melanostomus and Kudoa anatolica sp. nov. in the musculature, urinary bladder and kidney of Atherina hepsetus collected from the coast of Sinop on the Black Sea. Means ± SD (ranges) of mature spores of K. niluferi sp. nov. were 5.9 ± 0.1 (5.7-6.1) µm in length, 9.2 ± 0.2 (8.8-9.5) µm in width and 7.5 ± 0.3 (7.0-8.1) µm in thickness, while those of K. anatolica sp. nov. were 4.1 ± 0.3 (3.5-4.1) µm in length, 7.1 ± 0.2 (6.7-7.2) µm in width and 5.7 ± 0.2 (5.3-6.0) µm in thickness. In both parasite species, length and width of the 4 polar capsules were not equal and formed 3 distinct size classes, largest (1), intermediate (2) and smallest (1) in size. The prevalence and intensity of infection by K. niluferi sp. nov. were 12.8% and 20-29 parasites (per field-of-view, at 200× magnification), respectively, in the musculature of N. melanostomus. These values for K. anatolica sp. nov. were 32.1% and 10-19 parasites in the musculature as well as 2.9% and 20-29 parasites jointly in the kidney and urinary bladder of A. hepsetus. Phylogenetic analysis based on nuclear small subunit rDNA also suggested K. niluferi and K. anatolica as 2 novel species. These species appeared in the same lineage with K. nova and formed a Black Sea lineage.

Morphology, histology and phylogeny of Henneguya sinova sp. nov. (Myxobolidae: Myxozoa) infecting gills of Parablennius tentacularis in the Black Sea, Turkey.

Myxosporeans of the genus Henneguya have a global distribution and infect organs and tissues of both marine and freshwater fishes. Here we describe the morphological, histological and molecular characteristics of Henneguya sinova sp. nov. parasitizing the gill arches of tentacled blenny Parablennius tentacularis (Perciformes: Blenniidae) collected from the coast of Sinop on the Black Sea in Turkey. Several oval whitish plasmodia of different sizes in the gill arches of fish were found. The mature spores were rounded oval in frontal view, with a mean (range) total length 57.5 (51.5-68.0) µm; the spore body was 11.7 (11.3-12.0) µm in length by 7.6 (7.3-8.3) µm in width and 6.7 (6.6-6.8) µm in thickness. The caudal appendages, measuring 46.0 (40.0-55.0) µm in length, were very thin at the tapered end. The prevalence of infection by H. sinova sp. nov. was 35.5%. Phylogenetic analysis of nuclear small subunit ribosomal DNA (SSU rDNA) clearly suggested H. sinova as a new species which is clustered within the marine Henneguya lineage. Pairwise nucleotide similarities and DNA distance values of SSU rDNA between H. sinova sp. nov. and other related Henneguya species also supported this suggestion.

Molecular characterization and morphological aspects of Myxobolus parvus (Myxozoa) from Liza saliens (Mugilidae) off the Turkish Black Sea coasts.

Members of the phylum Myxozoa are among the most cosmopolitan parasites of fish, and the genus Myxobolus is the largest within the class Myxosporea in freshwater and marine environment from all over the world. Myxobolus parvus has been reported from mainly mugilid fishes from different localities including the Black Sea. Leaping mullet Liza saliens collected by fishermen off Sinop coasts of the Black Sea in the period between September 2014 and December 2015 was investigated for myxosporean parasites using conventional methods. M. parvus Schulman, 1962 was the only Myxobolus species identified and it was found in the gills, gall bladder, kidney tubules, and inside several cysts located on the lower jaw of examined fish in the present study. Morphometric data and all details of parasitic infection were determined and presented in tables and illustrated in figures. Molecular characterization was also conducted to reveal its position within Myxosporea. Two M. parvus samples from gills and kidney showed the same haplotype and appeared in the same sub-lineage with marine Myxobolus species. The closest haplotypes to M. parvus were Triactinomyxon sp. and Endocapsa sp. which are the actinosporeans forms of unknown myxozoan species. These data are the first in molecular characterization of M. parvus, its occurrence in lower jaw of leaping mullet along with its infection prevalence values off the Turkish Black Sea coasts.

Molecular and morphological description of Myxidium parvum (Cnidaria) from Salaria pavo (Blenniidae) in the Black Sea.

Members of the predominantly coelozioc genus Myxidum Bütschli, 1882 with more than 232 species have been reported from a wide variety of marine and freshwater fish species worldwide. In this study, 25 specimens of peacock blenny, Salaria pavo, were collected from Sinop on the Turkish Black Sea coast. The gills, fins, skin, urinary bladder, gal bladder, kidney, liver, gonads and smooth muscle tissue of the collected samples were investigated for myxosporean parasites. Myxidium parvum Yurakhno, 1991 was the only myxosporean found in the gall bladder of host fishes. Based on spore morphology, M. parvum had mostly overlapping measurement data of original description in spore length and width, polar capsule length but differed slightly in width; however, they were within the ranges previously reported from other blenniid host fish species in the Black Sea. Moreover, in this study, molecular analysis of the 18S rDNA gene of M. parvum isolates from S. pavo was done for the first time and our M. parvum genotypes appeared as sister to Myxidium incurvatum within the "Lineage II" of the marine Myxidium clade.

The effect of veneering materials on stress distribution in implant-supported fixed prosthetic restorations.

In this study, the effect of various materials used in fabricating superstructures for implant-retained fixed partial dentures on stress distribution around implant tissues was investigated. Five different mathematical models consisting of 11,361 nodes and 54,598 elements were constructed to study porcelain, gold alloy, composite resin, reinforced composite resin, and acrylic resin veneering materials using the 3-dimensional finite element analysis method. MARC K7.2/Mentat 3.2 software was used for the analysis. Reference points were determined on the cortical bone, where perpendicular, oblique, and horizontal forces were applied. Stress values created by oblique and horizontal forces appeared to be higher than those created by vertical forces. Stress seemed to be concentrated at the cortical bone around the cervical region of the implant. Gold alloy and porcelain produced the highest stress values in this region. Stresses created by acrylic resin and reinforced composite resin were 25% and 15% less, respectively, than porcelain or gold alloy. Porcelain and gold alloy produced stress values at the lingual implant sites that reached the ultimate strength values of the cortical bone.

The effect of weight loss of liquid on the diametral tensile strengths of various kinds of luting cements.

The role of water evaporation from the liquids of the cements were tested, and the effect of this loss on their strength was evaluated for 0, 10, 20 and 30 minute, intervals. After 30 minutes the evaporation of liquid from the cements was so high that they lost their luting consistency. The data suggests that the highest weight loss was with polycarboxylate cement liquids, with glass-ionomer and zinc phosphate cement liquids following respectively. However, when diametral tensile strength test values were evaluated it was determined that glass-ionomer exhibited the highest resistance to fracturing and zinc phosphate the lowest. Upon examination of samples which were fractured, while polycarboxylate and glass-ionomer cracked and split into large fragments, zinc phosphate cements fractured into a multitude of small pieces. On the basis of this study, it appears that the manufacturers' recommendations about the powder-to-liquid ratio and the mixing procedures is confirmed particularly and should be adhered to for optimal results.

Stress distribution on the metal framework of the implant-supported fixed prosthesis using different veneering materials.

PURPOSE: This study evaluated stress distribution in metal frameworks constructed on implants under masticatory forces using computer simulations. MATERIALS AND METHODS: Three-dimensional finite element analysis was used to study four different veneering materials-metal framework combinations using Calcitek implants. The veneering materials used in the study were porcelain, heat-polymerized poly(methyl methacrylate) resin, microfilled composite resin, and glass-modified composite resin. All computations were conducted for different levels on the buccal and lingual sides. RESULTS: Changing the veneering material on the prosthesis produced significant effects on stress levels and stress distribution on the metal frameworks. Stresses were concentrated along the marginal area of the prosthesis. Acrylic resin showed greater displacement than porcelain, probably because of its lower modulus of elasticity. CONCLUSION: In comparison to porcelain, more stress is borne by the acrylic resin-veneered metal framework under static loading.

Comparision of diametral tensile strength of microwave and oven-dried investment materials.

STATEMENT OF PROBLEM: Microwave drying technique for investment materials is believed to be timesaving by accelerating the elimination of free water content. PURPOSE: This study compared the diametral tensile strength of 4 investment materials used in removable partial denture framework fabrication. The investment materials were subjected to microwave and conventional oven drying at different time intervals. MATERIAL AND METHODS: Type III partial denture casting investments (Wirovest, Wiroplus, Biosint, PH2) were tested. A total of 160 specimens were prepared in cylindrical form at a height of 40 mm and a diameter of 20 mm, in accordance with the manufacturers' recommendations. Forty specimens were prepared from each product; 20 specimens were dried at 230 degrees C for 1 hour in an electric furnace, the other 20 were dried in a microwave oven for 10 minutes at 600 W. The dried specimens were tested at 2- and 4-hour intervals in diametral compression at a crosshead speed of 0. 5 cm/min. RESULTS: The microwave drying technique resulted in greater diametral tensile strength values for all investment materials. CONCLUSION: Within the limitations of this study, microwave drying of type III dental investment materials at 600 W for 10 minutes was, apart from strengthening the material, timesaving for the dental laboratory.

Comparison of microleakage properties of three different filling materials. An autoradiographic study.

The aim of this study was to compare the microleakage behaviour of three restorative materials using the autoradiographic method. The study was accomplished in vitro using freshly extracted human molars and a Ca45 radioisotope and autoradiography. Twenty-seven molar teeth were divided into three experimental groups of seven specimens each. Class II cavities were prepared at the mesio-occlusal aspect and restored with amalgam and two different composite resins. The restorations were finished, thermocycled and tested for microleakage, using the Ca45 radioisotope. The results were analysed using the Kruskal-Wallis analysis test. Amalgam exhibited more leakage compared with composite resins. However the differences among the leakage behaviours of three filling materials were not statistically significant (P=0.064).