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Thuringiensin (Thu), also known as β-exotoxin, is a thermostable secondary metabolite secreted by Bacillus thuringiensis. The chemical formula of Thu is C22H32O19N5P, and it is composed of adenosine, glucose, phosphoric acid, and gluconic diacid. 

2) How does the secondary metabolite been produced?  

Secondary metabolites are produced by microorganisms when one or more of the nutrients in the culture medium is depleted. In this case, the second metabolite of bacillus thuringiensis is produced during the sporulation phase. After the ingestion, the crystals are solubilized in the insects’ midguts in the alkaline condition. It will be proteolytically converted into a toxic core fragment. Then, the activated toxins bind to the receptor of apical microvillus membrane of epithelial midgut. The oligomerization occurs when the toxins enter the membrane. By increasing the cationic permeability of the membrane, the oligomers form pores or ion channels on it. Due to the free flux of ions, the membrane transport and cell lysis are disrupted. So, the insect dies.

3) Relate primary and secondary metabolism of the secondary metabolite 

The primary metabolism is the synthesis of the key precursor, gluconic diacid, using the products of thus, thuC, and thuD.  Gluconic acid is subsequently oxidized to gluconic diacid by UDP-glucose dehydrogenase (ThuD), which can directly oxidize a hydroxyl group to a carboxyl (ic) group. The secondary metabolism of secondary metabolite is gluconic diacid is bound to the ACP region of the nonribosomal peptide synthetase Thu2. A hydroxyl group on the C-1 residue of gluconic diacid forms a thioester bond with a sulfhydryl group of the ACP protein. Next, a UDP-glucose moiety is added onto the gluconic diacid-ACP complex by glycosyltransferase ThuF, and a 1,5-glycosidic bond is formed between glucose and gluconic diacid.

4) Which microbes is it from and what other microbes produce this secondary metabolite? (anis)

Bacillus thuringiensis

3) Relate primary and secondary metabolism of the secondary metabolite

Penicillin is a secondary metabolite of certain species of Penicillium and is produced when the growth of the fungus is inhibited by stress. It is not produced during active growth. Production is also limited by feedback in the synthesis pathway of penicillin.

α-ketoglutarate + AcCoA → homocitrate → L-α-aminoadipic acid → L-lysine + β-lactam

The by-product, l-lysine, inhibits the production of homocitrate, so the presence of exogenous lysine should be avoided in penicillin production.

4) Which microbes is it from and what other microbes produce this secondary metabolite?

Originated from Penicillium mold. Other microbes such as genetic engineered yeast can produce penicillin in laboratory 

Streptomycin

https://www.genome.jp/pathway/map00521 

The secondary metabolite which is streptomycin is produced by certain strains of Streptomyces griscus.

Streptomycin consists of aminocyclitol (streptidine), 6-deoxyhexose (streptose), and N-methyl-L-glucosamine moieties, which are formed by the pathway of independent biosynthetic.

All of the moieties are derived from D-glucose. The streptidine moiety is synthesized via myo-inositol, which is then oxidized at C-1 and transaminated to give scyllo-inosamine.

Primary metabolism included in streptomycin synthesis:

D-glucose : glycolysis

1L-myo-Inositol-1P : Inositol phosphate metabolism

From the primary metabolism which is glucose, then the glucose converts to the D-glucose 6-phosphate. The conversion of D-glucose 6-phosphate to 1L-myo-inositol 1-phosphate is catalyzed by 1L-myo-inositol 1-phosphate synthase (MIP synthase). 

Soil microbes ~ Streptomyces spp. (E.g Streptomyces griseus)

Reference: https://pubs.acs.org/doi/10.1021/ja052151d

Secondary metabolites are compounds produced during secondary metabolism (stationary phase) and the compounds produced have no direct relationship to the synthesis of cell material and natural growth. In this case, the secondary metabolite is PHA.

2) How does the secondary metabolite been produced?  

Secondary metabolites are produced by microorganisms when one or more of the nutrients in the culture medium is depleted. In this case, PHAs are usually produced when the microbes are cultured with nutrient-limiting concentrations of nitrogen, phosphorus, sulfur, or oxygen and excess carbon sources.

The primary metabolism involved in this case are biosynthesis of carbohydrates, De novo fatty acid synthesis and fatty acid b-oxidation. The primary metabolites produced (acetoacetyl-CoA, ( R)-3-hydroxyacyl-ACP and (S)-3-hydroxyacyl-ACP) from these 3 primary metabolisms act as a precursor/intermediate to initiate the secondary metabolism and produce secondary metabolites (PHA).

In this case, the microbe used is from Pseudomonas sp. while other PHA-producing bacteria are Cupriavidus necator and Bacillus megaterium.

Yes, it is secondary metabolite.

2) How does the secondary metabolite been produced? 
Produce from the precursor, Acetyl-CoA via phosphorylation, decarboxylation and reduction.

3) Relate primary and secondary metabolism of the secondary  metabolite
Primary metabolite produced from log phase, secondary metabolite produced from stationary phase. Secondary metabolites are derived from primary metabolism, they do not make up basic molecular skeleton of the organism. Its absence does not immediately curtail the life of an organism, a feature contrary to primary metabolite, but survival of the organism is impaired to a larger extent.

2. How does the secondary metabolite been produced? 

Produced by streptomycin when one or more nutrients is depleted. In this case, aminoglycoside

3.Relate primary and secondary metabolism of the secondary  metabolite

4) Which microbes is it from and what other microbes produce this secondary metabolite?

Kojic acid is a secondary metabolite isolated from Aspergillus fungi that has demonstrated skin whitening, antioxidant and antitumour properties among others.

2) How does the secondary metabolites been produced?

Fermentation of glucose. glucose is converted to d-gluconic acid by glucose dehydrogenase and d-gluconic acid is converted to kojic acid by gluconate dehydrogenase.

3) Relate primary and secondary metabolism of the secondary  metabolite?
Kojic acid biologically occurs in the direct fermentation of glucose in A. oryzae. The primary metabolism in the pathway is when the glucose is dehydrogenated by glucose dehydrogenase, to form gluconic acid δ-lactone. At this point, the reaction can continue via two different pathways, both of which carry out dehydrogenation, reduction, and dehydration to lead to the final product of kojic acid.

The two pathways are as shown below:

4) Which microbes is it from and what other microbes produce this secondary metabolites? 

2) How are photoautotrophs and photoheterotrophs similar and how do they differ?

Similarities

3) Group the photosynthetic bacteria according to its trophy and oxygenic/anoxygenic phototrophs

Oxygenic bacteria - cyanobacteria photoautotrophic 

ANIS SYAKIRA MOHAMAD A18SC0379
YAP YING YAN A18SC0493

STEVEN ANAK LILOI A18SC0483

NORARINA SURAYA MOHD RAZALI A18SC0431

1. What is the difference between oxygenic and anoxygenic phototroph?

The key difference between oxygenic and anoxygenic photosynthesis is that 

2. How are photoautotrophs and photoheterotrophs similar and how do they differ?

3. Group the photosynthetic bacteria according to its trophy and oxygenic/anoxygenic phototrophs

As an energy source and electron donor

Because they oxidize reduced sulphur compounds producing sulphuric acid, which causes their surroundings to become acidic. Thus, making this microbe capable of adapting to extremely acidic environments.

Rusticyanin is a blue copper protein and it is obligate acidophile chemolithoautotroph (Acidithiobacillus ferrooxidans).  Its function is to act as an electron transfer protein.

Can be found in the acidophilic sulfur bacterium Thiobacillus ferrooxidans.

Nitrosomonas: Ammonia (NH4+) to nitrite (NO2-)

Nitrobacter: Nitrite (No2-) to nitrate (NO32-)

Use carbon dioxide as a carbon source

Anammox reaction is a reaction which will oxidize the ammonium into dinitrogen gas by using nitrite (electron acceptor).

Anammox is anaerobic ammonium oxidation which will oxidize the ammonium into dinitrogen gas while aerobic nitrification will undergo oxidation, oxidized ammonia into nitrite.