As the concentration of CV in the growing medium grew, so did strain RB1's sensitivity to streptomycin. Cytochrome aa3 levels and streptomycin sensitivity both rise with increasing CV concentration in the growing medium. B. subtilis cannot accumulate streptomycin without cytochrome aa3 [1]. Streptomycin has an impact on tRNA selection. Mutations causing streptomycin resistance often localize to protein S12, and the majority of these variations show increased discrimination during tRNA selection [2].

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The accumulation of streptomycin by B. subtilis was measured using radiolabeled dihydrostreptomycin (DHS). Uptake was found to be time-dependent and correlated with the cellular concentration of cytochrome aa3. [1]
A spontaneous streptomycin-resistant mutant, strain RB95 (strC2), exhibited very low rates of DHS accumulation when grown under conditions where cytochrome aa3 was deficient, compared to the wild-type strain RB1. [1]
By varying the concentration of Casamino Acids in the growth medium, the cytochrome aa3 levels in both wild-type and mutant strains could be modulated. A positive correlation was observed: higher cytochrome aa3 concentrations led to higher rates of streptomycin accumulation. [1]
Growth susceptibility to streptomycin, measured by disk diffusion assays, also correlated with cytochrome aa3 levels. Strains with higher cytochrome aa3 content showed larger zones of inhibition, indicating greater susceptibility. [1]
The presence of an alternate terminal oxidase, cytochrome-617, was noted, and its concentration was often inversely related to that of cytochrome aa3, particularly in the strC mutant. This suggests that the specific type of terminal oxidase present influences streptomycin uptake. [1]

Antibiotic Accumulation Assay: Cells were grown to a density of 60 Klett units. Unlabeled streptomycin sulfate (58.2 μg/ml) and ³H-labeled dihydrostreptomycin sulfate (final specific activity 0.2 μCi/ml) were added to the culture, achieving a final streptomycin concentration of 58.5 μg/ml. At specified intervals (every 1.5, 3, or 10 minutes), 1.0 ml samples were taken and rapidly filtered onto polycarbonate filters (0.4 μm pore size) that had been pre-washed with concentrated medium containing 100 μg/ml streptomycin sulfate. The filters were then washed with 5 ml of 1.5 M NaCl, air-dried, and the radioactivity was counted in a scintillation cocktail to determine the amount of cell-associated antibiotic. [1]
Antibiotic Susceptibility Assay (Disk Diffusion): An aliquot (0.1 ml) of an overnight culture was mixed with 2.5 ml of 0.8% soft agar and poured onto plates containing 25 ml of the desired solid medium. After solidification, sterile blank disks (7 mm diameter) impregnated with 3 μl of a 100 mg/ml streptomycin sulfate solution (300 μg per disk for strain RB1, 600 μg for strain RB95) were placed on the agar. After 24 hours of incubation, the diameters of the zones of inhibition were measured with a vernier caliper. Duplicate measurements were averaged. [1]
Cytochrome Measurement: Cells were grown on solid media for 48 hours. Cytochrome components of intact cells were determined at liquid nitrogen temperature using a Hartree low-dispersion microspectroscope. Absorption band intensities were visually estimated and assigned relative concentration values on a scale of 0 to 5. For more detailed analysis, recorded absorption spectra were obtained with a spectrophotometer equipped with a high-intensity light source and a scattered-transmission accessory. [1]
Pyridine Hemochromogen Assay: To confirm the presence of heme a (from cytochrome aa3), membrane preparations were made from cells grown under conditions promoting cytochrome aa3 synthesis. Cells were treated with lysozyme, disrupted by passage through a French pressure cell, and centrifuged to remove debris. The supernatant was lyophilized and then resuspended in a solution of water, pyridine, and NaOH. Sodium dithionite was added, and the spectrum was recorded immediately. The absorption maximum for the pyridine hemochromogen of heme a is approximately 587 nm. [1]

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Similar to other aminoglycoside antibiotics, Streptomycin is rarely excreted into breast milk. Newborns appear to absorb small amounts of aminoglycoside antibiotics, but their serum concentrations are far lower than those achieved when treating neonatal infections, making systemic effects of Streptomycin unlikely. Even smaller amounts of Streptomycin are expected to be absorbed by older infants. Monitoring for potential effects on the infant's gut microbiota, such as diarrhea, candidiasis (e.g., thrush, diaper rash), or rare hematochezia (blood in stool), which may indicate antibiotic-associated colitis, should be conducted.
◉ Effects on Breastfed Infants
No relevant published information was found as of the revision date.
◉ Effects on Lactation and Breast Milk
An observational study found that Streptomycin did not inhibit lactation.

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[1]. Correlation between cytochrome aa3 concentrations and streptomycin accumulation in Bacillus subtilis. Antimicrob Agents Chemother. 1984 Oct;26(4):507-12.

[2]. Mutational analysis of S12 protein and implications for the accuracy of decoding by the ribosome. J Mol Biol, 2007. 374(4): p. 1065-76.

According to state or federal labeling requirements, Streptomycin sulfate may cause developmental toxicity. Streptomycin sulfate (2:3) (salt) is an antibacterial agent. It is a white to light gray or pale yellow powder with a slightly amine odor. Streptomycin sulfate is an aminoglycoside sulfate. Its function is related to Streptomycin. Streptomycin sulfate is the sulfate form of Streptomycin, an aminoglycoside antibiotic derived from Streptomyces griseus with antibacterial properties. Streptomycin sulfate binds to the S12 protein of the bacterial 30S ribosomal subunit, thereby inhibiting peptide chain elongation and protein synthesis, ultimately leading to bacterial cell death. It is an antibiotic produced by the soil actinomycete Streptomyces griseus. It works by inhibiting the initiation and elongation steps in protein synthesis. See also: Streptomycin (containing the active moiety)... See more...

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The study provides evidence that the accumulation of aminoglycosides like streptomycin in B. subtilis requires specific components of the electron transport chain, particularly cytochromes. The requirement for an electrochemical proton gradient (ΔμH+) for aminoglycoside uptake is well-established, and this study further suggests that specific components like cytochrome aa3 may play a direct role beyond just generating this gradient. [1]
The strC mutation in B. subtilis confers resistance to streptomycin and is associated with a deficiency in cytochrome aa3 under most growth conditions. However, this deficiency could be partially reversed by supplementing the growth medium with high concentrations of Casamino Acids, which also restored streptomycin susceptibility and uptake. [1]
The data suggest that a full complement of cytochrome aa3 is not necessary for streptomycin accumulation; a threshold level (perhaps 50% or less of the normal regulated level) appears sufficient to allow uptake rates consistent with growth inhibition. [1]
The authors propose that cytochrome aa3 is necessary for dihydrostreptomycin uptake by B. subtilis, based on the observed positive correlation between its concentration and both drug accumulation and growth inhibition. [1]

1456.433

3810-74-0

Streptomycin;57-92-1

19648

White to off-white solid powder

948.2ºC at 760 mmHg

527.3ºC

-85 ° (C=1, H2O)

30

42

18

95

1020

30

S(=O)(=O)(O[H])O[H].S(=O)(=O)(O[H])O[H].S(=O)(=O)(O[H])O[H].O([C@@]1([H])[C@@]([H])([C@@](C([H])=O)([C@]([H])(C([H])([H])[H])O1)O[H])O[C@@]1([H])[C@]([H])([C@@]([H])([C@]([H])([C@]([H])(C([H])([H])O[H])O1)O[H])O[H])N([H])C([H])([H])[H])[C@@]1([H])[C@@]([H])([C@]([H])([C@@]([H])([C@]([H])([C@]1([H])/N=C(\N([H])[H])/N([H])[H])O[H])/N=C(\N([H])[H])/N([H])[H])O[H])O[H].O([C@@]1([H])[C@@]([H])([C@@](C([H])=O)([C@]([H])(C([H])([H])[H])O1)O[H])O[C@@]1([H])[C@]([H])([C@@]([H])([C@]([H])([C@]([H])(C([H])([H])O[H])O1)O[H])O[H])N([H])C([H])([H])[H])[C@@]1([H])[C@@]([H])([C@]([H])([C@@]([H])([C@]([H])([C@]1([H])/N=C(\N([H])[H])/N([H])[H])O[H])/N=C(\N([H])[H])/N([H])[H])O[H])O[H]

QTENRWWVYAAPBI-YCRXJPFRSA-N

InChI=1S/2C21H39N7O12.3H2O4S/c2*1-5-21(36,4-30)16(40-17-9(26-2)13(34)10(31)6(3-29)38-17)18(37-5)39-15-8(28-20(24)25)11(32)7(27-19(22)23)12(33)14(15)35;3*1-5(2,3)4/h2*4-18,26,29,31-36H,3H2,1-2H3,(H4,22,23,27)(H4,24,25,28);3*(H2,1,2,3,4)/t2*5-,6-,7+,8-,9-,10-,11+,12-,13-,14+,15+,16-,17-,18-,21+;;;/m00.../s1

2-[(1R,2R,3S,4R,5R,6S)-3-(diaminomethylideneamino)-4-[(2R,3R,4R,5S)-3-[(2S,3S,4S,5R,6S)-4,5-dihydroxy-6-(hydroxymethyl)-3-(methylamino)oxan-2-yl]oxy-4-formyl-4-hydroxy-5-methyloxolan-2-yl]oxy-2,5,6-trihydroxycyclohexyl]guanidine;sulfuric acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ≥ 100 mg/mL (~137.23 mM)
DMSO :< 1 mg/mL

Solubility in Formulation 1: 100 mg/mL (137.23 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)