Two enzymes of diacylglyceryl-O-4'-(N,N,N,-trimethyl)homoserine biosynthesis are encoded by btaA and btaB in the purple bacterium Rhodobacter sphaeroides.

Betaine lipids are ether-linked, nonphosphorous glycerolipids that resemble the more commonly known phosphatidylcholine in overall structure. Betaine lipids are abundant in many eukaryotes such as nonseed plants, algae, fungi, and amoeba. Some of these organisms are entirely devoid of phosphatidylcholine and, instead, contain a betaine lipid such as diacylglyceryl-O-4'-(N,N,N,-trimethyl)homoserine. Recently, this lipid also was discovered in the photosynthetic purple bacterium Rhodobacter sphaeroides where it seems to replace phosphatidylcholine under phosphate-limiting growth conditions. This discovery provided the opportunity to study the biosynthesis of betaine lipids in a bacterial model system. Mutants of R. sphaeroides deficient in the biosynthesis of the betaine lipid were isolated, and two genes essential for this process, btaA and btaB, were identified. It is proposed that btaA encodes an S-adenosylmethionine:diacylglycerol 3-amino-3-carboxypropyl transferase and btaB an S-adenosylmethionine-dependent N-methyltransferase. Both enzymatic activities can account for all reactions of betaine lipid head group biosynthesis. Because the equivalent reactions have been proposed for different eukaryotes, it seems likely that orthologs of btaA/btaB may be present in other betaine lipid-containing organisms.

Setting home care standards.

Setting standards for home health care is a necessary component to ensuring the delivery of quality care efficiently and effectively. The generic standards established by the American Nurses' Association are reviewed while other resources available when pursuing the development of home health standards are described. The author discusses the concept of developing standards based on cost, quality, and process.

Clarifying roles and expectations in home care.

Home care nurses work in an entirely different environment from where they were trained. This unique situation requires understanding the difference in the nurse's role in the home, and establishing rules that promote a therapeutic environment.

Selecting a home care agency.

Selecting a home care agency must be a collaborative effort on the part of families and the discharging facility. Guidelines for selecting home care providers eases the transition from the acute care facility to home.

Understanding private insurance for funding pediatric home care.

Understanding families' insurance policies is key to assisting them in securing home care services for their chronically ill child. Developing skills in asking questions and securing information from the insurance company has become the responsibility of hospital discharge planners and home care nurses.