Relationship of the DNA content in the nuclei of Amoeba proteus to the food regimen]

The relative DNA content of isolated Amoeba proteus nuclei has been measured by cytofluorometry. With the amoeba strain studied, the generation time is roughly equal to 48 hours at 25 degrees C, and with the presence of food in the medium. After the synchronous divisions, amoebae were maintained in the medium either with or without food organisms (Tetrahymena pyriformis). DNA contents in the nuclei of both the amoebae groups were measured within 4 and 48 hours after division. Before 16 hours, the nuclear DNA contents did not differ in either group. Starting from 20 hours, the DNA amount in fed amoebae exceeded that in starved animals. On the whole, the differences in DNA quantity increased by a 48th hour after division, when the nuclei of the former contained 145% DNA of the latter. The results obtained suggest that the DNA synthesis in amoeba nuclei may proceed during the whole interphase, and that during the second half of interphase the content of DNA may depend on the feeding intensity in amoebae. After refeeding the starved animals, DNA contents in their nuclei increased to reach the same level as in the constantly fed amoebae seen in the end of interphase.     

Evaluation of the In Vitro Activity of Tobramycin as Compared with That of Gentamicin Sulfate

The in vitro activity of tobramycin was quantitatively compared with that of gentamicin sulfate against 195 bacterial isolates from clinical material. Tobramycin was found to be twice as active as gentamicin against isolates of Pseudomonas aeruginosa. Conversely, gentamicin proved fourfold more active than tobramycin against isolates of Serratia marcescens. Both drugs were of comparable activity against isolates of Staphylococcus aureus and the majority of the enterobacterial isolates other than S. marcescens. On the basis of the obtained data, the following criteria are proposed for the interpretation of diffusion susceptibility tests with 10-μg discs of gentamicin and tobramycin. Enterobacteriaceae and isolates of S. aureus are designated as susceptible to gentamicin and tobramycin if the zones of inhibition measure 15 mm or more in diameter; zones of 14 mm or less are indicative of resistance. Pseudomonadaceae are interpreted as sensitive to tobramycin and gentamicin if the inhibition zones measure at least 15 and 12 mm in diameter, respectively.     

Ability of female ixodid ticks to recover from poisoning with DDT in the process of feeding]

Ability of hungary females of Ixodes persulcatus, Haemaphysalis concinna and Dermacentor silvarum to feed and lay eggs after having been exposed to different DDT doses (LD100) has been studied. The ticks heavily injuried but still mobile can feed on the host and lay eggs, i.e. to overcome the poisoning. Clutches laid by these females do not differ from control ones. Loss of mobility deprives the ticks of the ability to fed. An increase in DDT dose (LD100 X 100, experiment with I. persulcatus) does not allow the ticks to feed even if the ability to movement is preserved.     

COPII collar defines the boundary between ER and ER exit site and does not coat cargo containers

COPII and COPI mediate the formation of membrane vesicles translocating in opposite directions within the secretory pathway. Live-cell and electron microscopy revealed a novel mode of function for COPII during cargo export from the ER. COPII is recruited to membranes defining the boundary between the ER and ER exit sites, facilitating selective cargo concentration. Using direct observation of living cells, we monitored cargo selection processes, accumulation, and fission of COPII-free ERES membranes. CRISPR/Cas12a tagging, the RUSH system, and pharmaceutical and genetic perturbations of ER-Golgi transport demonstrated that the COPII coat remains bound to the ER–ERES boundary during protein export. Manipulation of the cargo-binding domain in COPII Sec24B prohibits cargo accumulation in ERES. These findings suggest a role for COPII in selecting and concentrating exported cargo rather than coating Golgi-bound carriers. These findings transform our understanding of coat proteins’ role in ER-to-Golgi transport.     

A chromosome-scale assembly of the bilberry genome identifies a complex locus controlling berry anthocyanin composition

Bilberry (Vaccinium myrtillus L.) belongs to the Vaccinium genus, which includes blueberries (Vaccinium spp.) and cranberry (V. macrocarpon). Unlike its cultivated relatives, bilberry remains largely undomesticated, with berry harvesting almost entirely from the wild. As such, it represents an ideal target for genomic analysis, providing comparisons with the domesticated Vaccinium species. Bilberry is prized for its taste and health properties and has provided essential nutrition for Northern European indigenous populations. It contains high concentrations of phytonutrients, with perhaps the most important being the purple colored anthocyanins, found in both skin and flesh. Here, we present the first bilberry genome assembly, comprising 12 pseudochromosomes assembled using Oxford Nanopore (ONT) and Hi-C Technologies. The pseudochromosomes represent 96.6% complete BUSCO genes with an assessed LAI score of 16.3, showing a high conservation of synteny against the blueberry genome. Kmer analysis showed an unusual third peak, indicating the sequenced samples may have been from two individuals. The alternate alleles were purged so that the final assembly represents only one haplotype. A total of 36,404 genes were annotated after nearly 48% of the assembly was masked to remove repeats. To illustrate the genome quality, we describe the complex MYBA locus, and identify the key regulating MYB genes that determine anthocyanin production. The new bilberry genome builds on the genomic resources and knowledge of Vaccinium species, to help understand the genetics underpinning some of the quality attributes that breeding programs aspire to improve. The high conservation of synteny between bilberry and blueberry genomes means that comparative genome mapping can be applied to transfer knowledge about marker-trait association between these two species, as the loci involved in key characters are orthologous.