Pink colonies

Differential media these distinguish colonies of specific microbes from others. When a culture medium containing certain substances helps to distinguish the differing properties of different bacteria, it is called differential media, e.g., MacConkey agar. It is also an indicator medium. It contains peptone, agar, lactose, sodium taurocholate and nentral red. The lactose fermenters form pink colonies while non-lactose fermenters produce colourless or pale colonies. Blood agar it serves both as an enriched as well as an indicator medium and shows different types of haemolysis. 

Pick a single large pink colony from a freshly grown YPD plate of yeast strain VL6-48. Inoculate several milliliters of YPAD and grow overnight at 30°C with shaking. This starter culture may be stored at 4°C and used for several weeks. 

Cells are gram negative, ellipsoidal to rod shaped, measuring 0.4-1.2 by 1.0-3.0 pm, and polarly flagellated when motile. Colonies are smooth, raised to convex, entire and glistening on ethanol/glucose/yeast extract/calcium carbonate/ agar. Some strains produce pink colonies. 

While the above observation is interesting and could possibly have some implications for the control of the pink bollworm, the complexity of the steroid nucleus of ponasterone A and other molting hormone analogs and their weak insecticidal effect when applied topically or administered orally to most species of economically important insects may preclude their commercialization. The only commercial use of the molting hormone analogs thus far has been in the sericultural industry for the synchronization of cocoon spinning of silkworm colonies (17). 

The family Moraceae was named after the mulberry. Modus. The red mulberry. Modus rubra, is native to North America, where it occurs in moist woodlands. It produces a tasty, juicy fruit which is favored by birds, and although it is also good for people to eat, it is not economically important. The white mulberry. Modus alba, is native to Asia. In China, leaves of the white mulberry are fed to cultivated silkworms, a type of moth larva. The white mulberry became naturalized in North America during unsuccessful attempts to establish a silk industry in colonial America. Unlike the native red mulberry, the white mulberry is somewhat weedy, and is often found around homes, in disturbed sites, along fencerows, and in moist, second-growth bottomlands. Fruits of the white mulberry may be white, pink, red, or deep purple. The dark purple fruits inspired the name Modus nigra, although taxonomists have since determined this plant to only be a variety of Modus alba. 

Description Adults pear-shaped, Vm -Vs" insects with 2 short tubes projecting backward from the abdomen long antennae i een. pink, black, dusty gray, or with white d.db, coating with or without wings. Nymphs imilar to adults. Colonies develop quickly ... 

The small, bright red strawberry anemone (Corynactis califomica), shown in Figure 3.4, forms colonies in areas where the substrate is covered with rocks. The anemone s tentacles end in knobs that are pink and transparent. Although the strawberry anemone can reproduce sexually, it often divides by fission to form large colonies that cover 3 feet (0.9 m) or more of sand. 

Aureobasidium sp. are ubiquitous microorganisms. There are approximately 15 species of Aureobasidium. They are found in soil, forest soils, fresh water, fruit, wood, bathrooms and kitchens, on shower curtain, tile graft, textiles, among others, (see Fig. 13.5). Wet spores are disseminated by wind when spores dry out. Many other fungi, Aureobasidium sp. are common allergens (hay fever, asthma, pneumonitis, etc.). Colonies are usually of the shades of cream to pink, becoming dark brown with age. 

When growing on agar substrate, yeast isolates typically appear as larger opaque ( creamy ) colonies compared with smaller ( pinpoint ) transparent bacterial colonies. Additionally, color development (chromogenesis) provide immediate diagnostic information. For example, Rhodotorula sp. produces a salmon-pink-colored colony on laboratory media. The yeast is believed to be part of native vineyard flora and is occasionally encountered during routine platings. 

Colonies on MacConkey Agar are yellow or yellowish-pink color. 

In mutagenesis the main condition of success is the development of a sensitive and rapid method of mutant selection. Vitamin B12 production by propionic acid bacteria correlates with acid production. But the method of selection based on picking colonies with the maximal diameter of dissolution zones of calcium carbonate (added to solid medium) did not give positive results, since the size of colonies is not identical while acid production is dependent on the quantity of biomass. Selection based on the intensity of pink color that correlates with vitamin B12 production has a disadvantage in that selection of small mutations is made step by step, when differences in color can hardly be noticed by eye. Another method used was based on direct determination of vitamin B12 in single colonies. This method is labor-intensive and severely limits the testing of large numbers of colonies. 

Presumptive test using KF streptococcus agar An alternative method involves using KF streptococcus agar. Filter water through a sterile 0.45 pm filter and incubate for 48 h at 35°C + 0.5°C on KF streptococcus agar. Pink and red colonies indicate the presence of fecal streptococci and should be counted. 

Cells are gram negative, rod shaped, measuring 0.4-1.0 by 1.0-2.5 pm, and motile with peritrichous flagella. Colonies are smooth, entire, raised, shiny, and light brown, pink, to dark pinkish on glucose/peptone/yeast extract agar. 

Yeast colonies produced a pink color on DRBC which facilitated its identification, whereas in OCY agar yeast colonies took on a cream or clear color. Bacterial colonies were not detected on the media. However, the presence of bacteria on DRBC was reported by Korburger et al. (1985), in their evaluation of molding ground meat and carrots. In addition, bacterial development was observed in wheat flour and corn meal samples in the latter study. 

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