Biomedical Applications of Synthetic Melanotropins

Alpha-melanotropin (alpha-melanocyte stimulating hormone, alpha-MSH) is a hormone produced by the pituitary gland of most vertebrate animals. This melanotropic peptide, Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2, regulates melanin pigmentation of the skin of some mammals. Although MSH may be absent from the human pituitary gland, this peptide can stimulate pigment formation in human skin. We have synthesized several analogues of alpha-MSH, which are superpotent, prolonged-acting, and resistant to inactivation by serum enzymes. One such analogue, [NLe⁴, D-Phe⁷]alpha-MSH, has proven particularly useful in a number of physiological studies. In addition, some [Nle⁴, D-Phe⁷]-substituted fragment analogues of MSH are even more active than the native hormone, alpha-MSH. For example, these analogues are 100–1,000 times more active than alpha-MSH in stimulating S-91 mouse melanoma tyrosinase activity in vitro. We have successfully labeled one such peptide to high specific activity; this melanotropin, [³H]-Ac-[Nle⁴, D-Phe⁷]alpha-MSH_4–11NH₂, has been shown by others to bind to B16 melanoma cells. We have also conjugated several ligands (fluorescein and biotin) to [Nle⁴, D-Phe⁷]alpha-MSH. These melanotropin conjugates might prove useful for melanotropin receptor studies and for the clinical localization of metastatic melanoma. We have demonstrated that [Nle⁴, D-Phe⁴]alpha-MSH can be topically applied and transdermally delivered across the skin of mice and humans in vitro, as determined by bioassay and RIA. Initial toxicologic studies indicate that the analogue is nontoxic to mice and is not mutagenic. Studies are underway to determine whether this analogue may prove useful as a “tanning hormone” for increasing the pigmentation of light-skinned individuals or possibly even for treating people with certain hypopigmentary disorders.     

Isolation and characterization of microsatellite loci in Cylindrocladium pauciramosum

Ten polymorphic microsatellite markers were developed for Cylindrocladium pauciramosum, a plant pathogen with a wide host range, which poses a serious problem in South African Eucalyptus nurseries. Polymorphism was evaluated on 43 isolates collected from Colombia and South Africa. Each locus had between three and six alleles. Testing for random mating showed multilocus equilibrium for a population of 40 isolates from a South African forestry nursery. Cross‐species transferability tested for 19 other Cylindrocladium species found amplification only in C. spathulatum, which is phylogenetically closely related to C. pauciramosum.     

Isolation and characterization of microsatellite loci in Cylindrocladium parasiticum

Twelve polymorphic microsatellite markers were developed for Cylindrocladium parasiticum, a plant pathogen with a wide host range and the causal agent of the serious disease of peanuts (Arachis hypogaea) known as cylindrocladium black rot (CBR). Polymorphism was evaluated on 17 isolates from different hosts and regions. Each locus had between two and six alleles. Cross‐species transferability tested for 20 other Cylindrocladium species found amplification only in Cylindrocladium pacificum, which is phylogenetically closely related to C. parasiticum.     

Development of polymorphic markers for the root pathogen Thielaviopsis basicola using ISSR‐PCR

Thielaviopsis basicola is a soil‐borne fungal pathogen affecting many important agricultural crops. Little is known regarding the population biology or origin of this pathogen. Polymorphic markers developed for Ceratocystis fimbriata, a species complex phylogenetically closely related to T. basicola, were tested and found not to be useful for T. basicola. In this study 14 primer pairs, seven of which resulted in the amplification of single polymorphic fragments in T. basicola were developed. These primers will enable further studies on this economically important pathogen, and will result in an enhanced understanding of its population structure in different parts of the world.     

A biological basis for bat conservation in British woodlands–a review

Fifteen species of insectivorous bats are resident in Britain. The numbers of most species have declined drastically in recent years and all are now fully protected under the Countryside and Wildlife Act 1981. Forests and woodlands offer foraging and roosting habitats for all species and it is important for Forest Managers to be aware of the impact which management practices may have on bat populations. Current knowledge on the importance of woodlands for roosting, feeding, water and breeding is reviewed and initial management guidelines for the enhancement of forests for bats proposed. Future research needs are discussed.     

Nutritional Factors Influencing the Production of Sclerotia by Certain Fungi

In various fungi (Botrytis cinerea, B. allii, Sclerotinia gladioli,Sclerotiun cepivorum, S. rolfsii, and Rhizoctonia solani) theinitiation of sclerotia, their further development to full sizeand their maturation were three distinct stages with differentnutritional requirements. These processes were followed on peptone-saltsmedia with a variety of carbon sources (carbohydrate or mannitol)ranging in concentration between 0·5 and 3 per cent.The nitrogen nutrition was varied in the presence of 2 per cent.glucose with peptone replaced by asparagine, potassium nitrate,or ammonium salts. All were suitable provided a high aciditydid not develop. Urea was unsatisfactory. Details given includethe rate of sugar utilization in some examples.     

Finding a Place for the Commonplace: Hurricane Katrina, Communities, and Preservation Law

The aftermath of Hurricane Katrina drew attention to commonplace landscape markers that create for a community a sense of place— that connection between people and places crucial to a sense of corporate and individual identity and heritage. There is a legal context for sense of place within extant federal preservation legislation. Nevertheless, many such markers with special meanings for residents have been overlooked in federal documentation, the cornerstone of which is the National Register of Historic Places. Grassroots efforts and national media coverage have helped forge a niche for sense of place within the recovery plans and policy emerging in the affected region. However, it is unclear whether this will carry over into practice. In terms of long-term policy shifts, remedying the shortcomings highlighted by Katrina may require changes to the National Historic Preservation Act and its associated guidelines and regulations, or it may entail a new approach altogether.     

An Ultrastructural Study of the Feeding Apparatus of Peranema trichophorum

A model of the feeding apparatus of Peranema trichophorum Ehrenberg has been constructed from electronmicrographs. A common opening leads via a short anterior canal to the reservoir and cytostome. The cytostome lies close to the internal opening of the canal, and can be moved forward during feeding, closing the passage to the reservoir, and displacing the flagella. The cytostome is supported by the rodorgan in its floor and a double serrated marginal lamella arching over its upper rim from dense bodies lying lateral to the cytostome. A working hypothesis for the movement of the feeding apparatus is proposed. The elaborate system of articulating lamellae operates through these dense bodies which may act as “hinge joints.” The rodorgan is pulled forward by contraction of longitudinal lamellae attached near the bases of the rods. Cytoplasmic pressure may also be involved. It is suggested that the pull is transmitted through the dense bodies and 2 anchoring lamellae to crescentic canal thickenings on either side of the canal opening. The cytostome, rodorgan and double serrated marginal lamella move forward to fill the external opening of the canal, now enlarged by sideways pull from the anchoring lamellae. Withdrawal of these structures sucks food into the cytostomal sac to be packed down by contraction of the double serrated lamella. It is postulated that the rodorgan operates through adhesion and cytolysis and is not adapted for piercing. A conspicuous striated fibril and associated groups of microtubules in the left wall of the reservoir are cytoskeletal structures.