APOLAR EMBRYOS OF FUCUS RESULTING FROM OSMOTIC AND CHEMICAL TREATMENT

Embryos of the brown alga Fucus vesiculosas L. were grown as populations in glass petri dishes in seawater at 15 C in continuous low-intensity unilateral fluorescent illumination for periods up to 2 weeks. A quantitative estimate of increase in nuclear number was made from acetocarmine squash preparations of samples taken at 12-or-24 hr intervals. Over the period of 2-6 days embryos showed a doubling time of about 12-18 hr. Under normal seawater culture conditions each embryo formed a single rhizoid. When grown in seawater supplemented with sugar concentrations above 0.4 m , Fucus embryos developed as multicellular spherical embryos lacking rhizoids. In 0.6 m sucrose-seawater, 97% of the embryos were apolar at 2 days; only 37% were apolar at 4 days, many having recovered from the sucrose inhibition. Some embryos remained apolar after growth in 0.6 m sucrose for 2 weeks. Nuclear counts showed that sucrose-seawater markedly inhibited the rate of cell division. Other sugars including D-glucose, D-fructose, D-galactose and the sugar alcohol D-mannitol were also effective. When apolar embryos grown in sucrose-seawater were returned to seawater, embryo growth resumed at the normal seawater rate, judged from nuclear counts. Such embryos formed multiple rhizoids, varying from two to eight rhizoids per embryo, which developed on the embryo quadrant or half away from the unilateral light. Each of the multiple rhizoids originated from a single small cell in the periphery of the multicellular spherica embryo. Thus the rhizoid-forming stimulus apparently had been subdivided among a number of the cells of the apolar embryos. The implications of this finding are discussed. Attempts to produce multiple rhizoids by treatment of embryos with indoleacetic acid or 2,4-dichlorophen-oxyacetic acid failed. However, embryos treated with 10⁻⁴ M or 5 × 10⁻⁵ m 2,3,5-triiodobenzoic acid formed 40 and 30% multiple rhizoids, respectively, suggesting that some chemical, perhaps hormonal, mechanism is involved in polarization and rhizoid initiation in Fucus embryogenesis.     

Complementation in Nonconidiating Mutants of Trichoderma

Nonconidiating (Con(-)) mutants were isolated from wild-type and color mutants of the fungus Trichoderma viride Pers. ex Fries. Heterokaryons were easily produced and maintained, and the complementation relationships among the Con(-) mutants were established. Most Con(-) mutants could complement one or more of the other Con(-) mutants. When marked Con(-) mutants were mixed with marked Con(+) testers, conidiating heterokaryons were formed. The conidia thus obtained produced only the parental type colonies after replating, indicating that nonconidiation is a nuclear characteristic. Allowing two Con(-) colonies to meet and produce a heterokaryon, it was found that the migration of nuclei reached a rate of 5 mm per hr, which is several times greater than the rate of hyphal elongation; it was also found that heterokaryosis of a mycelial region preceded its ability to conidiate.     

Study of the inheritance of sex expression in the cucumber. The interaction of major genes with modifying genetic and non-genetic factors

Summary Two major genes and a complex of polygenes affecting sex expression inCucumis sativus L. as well as their interaction with some nongenetic factors were investigated in the present study. The genetic factorst was found to affect sex by inducing a shift of the predetermined flowering pattern of this plant, in the direction of its base. As this pattern is composed of a staminate stage followed by a mixed (staminate-pistillate) stage and a pistillate stage, a double dose ofst will induce a change from the normal monoecious sex expression (to absolute gynoecism.The second major gene studied,m, known previously to control sex in the individual flower (m/m—andromonoecious,M—monoecious), also interacts with factors affecting the flowering pattern by inducing male tendency.Using an ordinary commercial monoecious stock additional modifying factors for sex expression were demonstrated, by eight generations of selection for high (in male direction) and for low (in female direction) node number to the first pistillate flower. A comparison of the means and frequency distributions of node number of the two selected lines, their F₁ and F₂, indicated polygenic control of this character.It was found that two non-genetic factors, day length and gibberellic acid (GA), may mimic the genetic factors for sex expression. Furthermore, evidence was presented, indicating that this sex controlling ability of GA and the modifying genes may be based on physiological conditions common to those two genetic and nongenetic factors.The overall mechanism of sex control in the cucumber and in other plants was discussed and a hypothetic model for the evolution of dioecism in flowering plants was proposed.     

Differential effects of deuterium oxide on the growth and morphogenesis of Trichoderma viride

Trichoderma viride can be grown in deuterium oxide (D₂O) concentrationsas high as 99.7%. Increasing concentrations of D₂O (25–90%)progressively extend the lag phase in growth, but do not greatlyaffect the linear growth rate itself. The minimum age and sizeof colony required for photoinduction of the conidiation processis also increased. In 95% D₂O, although growth rates are stillrelatively high, both photomorphogenesis and dark conidiationare completely blocked. This block does not appear to involvethe photoprocess itself, but rather post photoinductive processessuch as differentiation of conidiophores. These observations point to an alternative, or at least additional,hypothesis to the one frequently cited—that D₂O acts throughstabilizing or "temperature lowering mechanisms. (Received January 6, 1978; )     

Comparsion ofin vitro activities of antifungal drugs and propolis against yeasts isolated from patients with superficial mycoses

Thein vitro susceptibilities of propolis and antifungal drugs were determined against some yeasts isolated from patients with superficial mycoses. The agents tested included fluconazole, itraconazole, ketoconazole, terbinafine and propolis. MICs were determined by the broth microdilution technique following National Committee for Clinical Laboratory Standards document M27-P. For allCandida albicans isolates from the patients with superficial mycoses, ketoconazole presented higher (P<0.05) efficiency than that of the other antifungal agents tested. The geometric mean MIC values of antifungal drugs and propolis against the yeasts tested ranged from 0.087 to 12.69 μg/mL and 0.4–0.6 μg/mL, respectively. Propolis also showed an important antifungal activity against the yeasts tested, MIC ranges of the propolis were between 0.01–1.65 μg/mL. Based on these results, propolis requires further investigation as a potential agent for the treatment of superficial mycoses.     

Long COVID and its Management

The pandemic of COVID-19 is the biggest public health crisis in 21^st Century. Besides the acute symptoms after infection, patients and society are also being challenged by the long-term health complications associated with COVID-19, commonly known as long COVID. While health professionals work hard to find proper treatments, large amount of knowledge has been accumulated in recent years. In order to deal with long COVID efficiently, it is important for people to keep up with current progresses and take proactive actions on long COVID. For this purpose, this review will first introduce the general background of long COVID, and then discuss its risk factors, diagnostic indicators and management strategies. This review will serve as a useful resource for people to understand and prepare for long COVID that will be with us in the foreseeable future.     

A Turkish family with Nance-Horan syndrome due to a novel mutation

Nance-Horan Syndrome (NHS) is a rare X-linked syndrome characterized by congenital cataract which leads to profound vision loss, characteristic dysmorphic features and specific dental anomalies. Microcornea, microphthalmia and mild or moderate mental retardation may accompany these features. Heterozygous females often manifest similarly but with less severe features than affected males. We describe two brothers who have the NHS phenotype and their carrier mother who had microcornea but not cataract. We identified a previously unreported frameshift mutation (c.558insA) in exon 1 of the NHS gene in these patients and their mother which is predicted to result in the incorporation of 11 aberrant amino acids prior to a stop codon (p.E186Efs11X). We also discussed genotype–phenotype correlation according to relevant literature.