Proteolytic activity and general characteristics of a marine bacterium, Aeromonas proteolytica sp. N

Merkel, Joseph R. (Fort Johnson Marine Biological Laboratory, College of Charleston, Charleston, S.C.), Eugene D. Traganza, Barid B. Mukherjee, Travis B. Griffin, and J. M. Prescott. Proteolytic activity and general characteristics of a marine bacterium, Aeromonas proteolytica sp. n. J. Bacteriol. 87:1227-1233. 1964.-A highly proteolytic bacterial species was isolated from the alimentary canal of the marine borer, Limnoria. The morphological and biochemical characteristics of the organism indicated that it was a new Aeromonas species, for which the name A. proteolytica is proposed. When freshly isolated, the organism required seawater for growth; but, upon prolonged culture in the laboratory, it was able to grow in media of greatly reduced salt concentration, provided that relatively large amounts of peptone were supplied. Peptone or hydrolysates of casein were capable of supplying all organic nutrients required for growth and proteinase production. Certain individual amino acids were also able to furnish all energy, carbon, and nitrogen requirements. Inorganic nitrogen was utilized in the presence of citrate, but could not serve as the only source of nitrogen in the presence of glucose. The organism was facultatively anaerobic, but best growth and proteinase production occurred only with vigorous aeration. The amount of growth obtained in 24 hr increased rapidly as the incubation temperature was increased up to a maximum of 40 C, but no growth occurred at 42 C.     

A translocation heterozygote in garden Canna

A case of translocation heterozygosity has been discovered in gardenCanna. Morphologically the heterozygote is distinctive, being a pygmy type with small flowers which do not open. Cytologically it shows a ring or a chain of 4 plus 7 bivalents. The present observations reveal that rings disjunct usually in adjacent, and chains in an alternate manner. The subsequent course of meiosis is normal. The variety is totally sterile both after self and cross pollination. It has very likely arisen as a hybrid between two parents differing in one interchange.     

Role of Leuconostoc mesenteroides in Leavening the Batter of Idli, a Fermented Food of India

The fermentation of the batter of idli, a fermented food of India, was studied. The microorganisms responsible for the characteristic changes in the batter were isolated and identified. Although there is a sequential change in the bacterial flora, the predominant microorganism responsible for souring, as well as for gas production, was found to be Leuconostoc mesenteroides. In the later stages of fermentation, growth of Streptococcus faecalis and, still later, of Pediococcus cerevisiae becomes significant. The fermentation of idli demonstrates a leavening action caused by the activity of the heterofermentative lactic acid bacterium, L. mesenteroides. As far as is known, this is the first record of a leavening action produced exclusively by the activity of a lactic acid bacterium.     

Biosynthesis of triacylglycerols containing very long chain monounsaturated acyl moieties in developing seeds

Particulate (15,000g) fractions from developing seeds of honesty (Lunaria annua L.) and mustard (Sinapis alba L.) synthesize radioactive very long chain monounsaturated fatty acids (gadoleic, erucic, and nervonic) from [1-¹⁴C]oleoyl-CoA and malonyl-CoA or from oleoyl-CoA and [2-¹⁴C]malonyl-CoA. The very long chain monounsaturated fatty acids are rapidly channeled to triacylglycerois and other acyl lipids without intermediate accumulation of their CoA thioesters. When [1-¹⁴C]oleoyl-CoA is used as the radioactive substrate, phosphatidylcholines and other phospholipids are most extensively radiolabeled by oleoyl moieties rather than by very long chain monounsaturated acyl moieties. When [2-¹⁴C]malonyl-CoA is used as the radioactive substrate, no radioactive oleic acid is formed and the newly synthesized very long chain monounsaturated fatty acids are extensively incorporated into phosphatidylcholines and other phospholipids as well as triacylglycerols. The pattern of labeling of the key intermediates of the Kennedy pathway, e.g. lysophosphatidic acids, phosphatidic acids, and diacylglycerols by the newly synthesized very long chain monounsaturated fatty acids is consistent with the operation of this pathway in the biosynthesis of triacylglycerols.     

Cystosarcoma phyllodes. Diagnosis by fine needle aspiration cytology.

The cytologic features of 10 benign, 2 borderline and 5 malignant phyllodes tumors were studied, and an attempt was made to correlate the cytologic findings with corresponding histologic categories. Seventy-five percent of the benign and borderline tumors were interpreted as benign cystosarcoma phyllodes on fine needle aspiration cytology. Eighty percent of the malignant phyllodes tumors were identified as malignant lesions cytologically. The cytologic features assessed were the epithelial:stromal ratio and morphology of the stromal component, including the degree of atypia, mitotic activity, capillary vessels traversing the stromal fragments, presence of foamy macrophages, histiocytic giant cells and bipolar naked nuclei. A diagnosis of phyllodes tumor was suggested cytologically by the presence of both epithelial and stromal elements; the stroma was present as cellular "phyllodes fragments" and isolated mesenchymal cells. The parameters suggesting malignancy were extreme paucity or absence of epithelial elements and stromal cells in diffuse sheets and clusters less cohesive than normal, with marked stromal atypia and mitotic activity.     

Construction of vector of Brevibacterium lactofermentum and study of its stability in continuous culture.

A 5.7-kb vector plasmid pBK2 was constructed by ligating the kanamycin resistance gene from Escherichia coli plasmid pACYC177 to an endogenous cryptic 4.4-kb plasmid of Brevibacterium lactofermentum ATCC 21086. The vector replicates efficiently and is stably maintained in the host and other coryneforms. However, the copy number varied from 50 to 10 per chromosome-equivalent under different culture conditions. Continuous culture studies showed instability when low dilution rates were used. Co-culture experiments were performed at various dilution rates to measure the growth rate ratio (alpha) of the plasmid-free cells to the plasmid-containing cells. It was observed that at low dilution rates the value of alpha was higher than that at high dilution rates. Thus, the instability of the plasmid can be attributed to the increase in alpha at low dilution rates. Modelling of instability using a random partitioning model of plasmid segregation and experimentally obtained values of alpha showed agreement with experimental data. This demonstrated that active partitioning is not the operative mechanism for plasmid segregation in this case.     

A 43 kDa DNA binding protein from the pea chloroplast interacts with and stimulates the cognate DNA polymerase.

A DNA binding protein with DNA polymerase 'accessory activity' has been identified and purified to apparent homogeneity from pea chloroplasts. This protein consists of a single subunit of 43 kDa and binds to DNA regardless of its base sequence and topology. It increases cognate DNA polymerase-primase activity in a dose dependent manner. Using solid phase protein-protein interaction trapping and co-immunoprecipitation techniques, the purified protein was found to associate with the chloroplast DNA polymerase. The chloroplast DNA polymerase also binds directly to the radioiodinated 43 kDa protein. The specific interaction between 43 kDa protein and chloroplast DNA polymerase results in the synthesis of longer DNA chains. The 43 kDa protein, present abundantly in the pea chloroplast, appears to increase processivity of the chloroplast DNA polymerase and may play an important role in the replication of pea chloroplast DNA.     

Molecular cloning and sequencing of an operon, carRS of Azospirillum brasilense, that codes for a novel two-component regulatory system: demonstration of a positive regulatory role of carR for global control of carbohydrate catabolism.

A pleiotropic carbohydrate mutant, CR17, of Azospirillum brasilense RG (wild type) that assimilates C4 dicarboxylates (succinate and malate) but not carbohydrate (fructose, arabinose, galactose, glycerol, and gluconate) as C sources for growth was used to identify the car (carbohydrate regulation) locus by complementation analysis. The 2.8-kb genomic fragment that complemented the Car- defect of CR17 and overlapped the fru operon (S. Chattopadhyay, A. Mukherjee, and S. Ghosh, J. Bacteriol. 175:3240-3243, 1993) has now been completely sequenced. The sequence contains an operon, carRS, coding for two proteins, CARR and CARS, having 236 and 352 amino acid residues, respectively. The 3'-flanking region of the carRS operon showed sequence homology with the 5' terminus of the fruB gene of a related bacterium, Rhodobacter capsulatus. A complementation study with carRS deletion clones showed that only the carR+ gene was required to complement the Car- defect of CR17, signifying that the carbohydrate pleiotropy was due to a lesion within this gene. Although the 2.8-kb DNA containing the carRS operon when introduced by conjugation into CR17 also complemented the Car- defect, the complemented transconjugant was unable to utilize succinate as a C source. The reason for this is not clear. A sequence analysis of the two protein products strongly suggests that the protein pair may constitute a novel two-component regulatory system for global expression of carbohydrate catabolic pathways in A. brasilense.