Chemical Composition and Mechanism of Vibriocidal Action of Essential Oil from Resin of Protium heptaphyllum

Protium heptaphyllum is a plant widely distributed in Brazilian ecosystems that produce a resin which has pharmacological activities. In this study, the chemical composition, antimicrobial and antibiofilm activity, and the possible mechanism of action against the bacterium V. parahaemolyticus of essential oil from P. heptaphyllum (EOPH) were investigated. Twenty-two components were detected in EOPH, and β-phellandrene (60.68%) had the majority. The inhibition halo, MIC, and MBC values were 11 mm, 2 mg/mL, and 8 mg/mL, respectively. Biofilm biomass inhibition and biomass reduction of the preformed biofilm were detected at 4 mg/mL EOPH concentration. The assays of cell constituent release and membrane permeability indicated that EOPH may disrupt the cell membrane, leading to leakage of intracellular constituent as reducing sugars and materials with an absorbance of 260 nm.

Erythropoiesis-inhibiting factor(s) (EIF): methodologic studies

Erythropoiesis-inhibiting factors (EIF) have been demonstrated in plasma from hypertransfused animals and from polycythemic individuals during periods of hyperoxia, but there is a decided discrepancy in the data published. In the present paper methodologic variations of a bioassay for demonstrating the erythropoiesis-inhibiting factor are discussed. In these studies no inhibitor of erythropoiesis could be demonstrated in plasma from hypoxia-induced polycythemic mice (HPM) on posthypoxic day 5. Injections of RBC or an equal amount of hemolyzed RBC were capable of suppressing the stimulatory effects of ESF, indicating that a red cell constituent may be responsible for the inhibitory effect observed. Transfusion-induced polycythemic mice (TPM) were therefore considered to be less suitable for demonstrating erythropoiesis inhibitors. Our results from testing several doses of a urinary EIF in normal mice, TPM and HPM, indicated that the HPM provided the most sensitive assay system. A similar effect was obtained with hypoxia-induced polycythemic rats. The most marked effect was seen in HPM when the EIF was injected shortly before administering the ESF, while the effect was less pronounced when the EIF was injected 24 hr before or after the ESF.

Erythropoiesis-inhibiting factor(s) (EIF): methodologic studies

Erythropoiesis-inhibiting factors (EIF) have been demonstrated in plasma from hypertransfused animals and from polycythemic individuals during periods of hyperoxia, but there is a decided discrepancy in the data published. In the present paper methodologic variations of a bioassay for demonstrating the erythropoiesis-inhibiting factor are discussed. In these studies no inhibitor of erythropoiesis could be demonstrated in plasma from hypoxia-induced polycythemic mice (HPM) on posthypoxic day 5. Injections of RBC or an equal amount of hemolyzed RBC were capable of suppressing the stimulatory effects of ESF, indicating that a red cell constituent may be responsible for the inhibitory effect observed. Transfusion-induced polycythemic mice (TPM) were therefore considered to be less suitable for demonstrating erythropoiesis inhibitors. Our results from testing several doses of a urinary EIF in normal mice, TPM and HPM, indicated that the HPM provided the most sensitive assay system. A similar effect was obtained with hypoxia-induced polycythemic rats. The most marked effect was seen in HPM when the EIF was injected shortly before administering the ESF, while the effect was less pronounced when the EIF was injected 24 hr before or after the ESF.

A "MICROTUBULE" IN A BACTERIUM

A study of the anchorage of the flagella in swarmers of Proteus mirabilis led to the incidental observation of microtubules. These microtubules were found in thin sections and in whole mount preparations of cells from which most of the content had been released by osmotic shock before staining negatively with potassium phosphotungstate (PTA). The microtubules are in negatively stained preparations about 200 A wide, i.e. somewhat thicker than the flagella (approximately 130 A). They are thus somewhat thinner than most microtubules recorded for other cells. They are referred to as microtubules because of their smooth cylindrical wall, or cortex, surrounding a hollow core which is readily filled with PTA when stained negatively. Since this is probably the first time that such a structure is described inside a bacterium, we do not know for certain whether it represents a normal cell constituent or an abnormality, for instance of the type of "polysheaths" (16).

STEROIDS IN THE SEMEN OF DOGFISH (SQUALUS ACANTHIAS)

SUMMARY 11-Deoxycorticosterone has been found in surprisingly high concentration (ca. 500 μg./100 g.) in the semen of Squalus acanthias. Accompanying steroids are progesterone (8 μg./100 g.), androstenedione (2 μg./100 g.), dehydroepiandrosterone (2 μg./100 g.), pregnenolone (14 μg./100 g.), androsterone (< 5 μg./100 g.) and possibly aldosterone (< 1 μg./100 g.); three unidentified compounds were also detected. Only a small proportion (ca. 5%) of the 11-deoxycorticosterone is present in that portion of the semen which passes an ultrafilter. The remainder is either present as a sperm cell constituent or is bound to extracellular mucoids or proteins.