Smallholder rubber and swidden agriculture in Borneo: A sustainable adaptation to the ecology and economy of the tropical forest

This is a study of the role of Para rubber cultivation in a system of swidden agriculture in Indonesian Borneo. Such smallholdings produce most of Indonesia’s rubber, which is the country’s largest agricultural generator of foreign exchange. Rubber integrates well into Bornean systems of swidden agriculture: the comparative ecology and economy of Para rubber and upland swidden rice result in minimal competition in the use of land and labor — and even in mutual enhancement — between the two systems. Rubber occupies a distinct niche in the farm economy: it meets the need for market goods, while the swiddens meet subsistence needs. The intensity of production on these smallholdings is, as a result, characteristically low (and may even vary inversely with market prices). This reflects the independence of these smallholders from external economic and political influences, which has been the key to their historical success. The special virtues of such “composite systems” merit greater attention by development planners. Penilitian ini mempelajari peranan karet rakyat sebagai pasangan bagi sistem perladangan di Kalimantan-Indonesia. Perkebunan karet rakyat merupakan penghasil utama karet Indonesia, yang merupakan penyumbang pertanian terbesar bagi devisa negara. Karet rakyat membaur dengan baik dalam sistem perladangan di Kalimantan: pembandingan ekologi dan ekonomi antara karet rakyat dan sistem perladangan menunjukkan persaingan yang minimum dalam pemakaian lahan dan tenaga kerja—dan bahkan saling menguntungkan—antara kedua sistem tersebut. Karet rakyat menempati kedudukan yang penting dalam ekonomi usaha para peladang: yaitu memenuhi kebutuhan barang-barang pasar, sedangkan sistem perladangan memenuhi kebutuhan pokok hidup. Intensitas produksi perkebunan karet rakyat oleh karena itu, brasanya agak rendah (yang kadang-kadang berbeda berbalikan dengan harga pasar). Hal ini menggambarkan ketidak-bergantungan petani karet pada pengaruh-pengaruh ekonomi dan politik dari luar, dan ini merupakan kunci sukses mereka. Hal-hal khususyang menguntungkan dari sistem terpadu inipatut mendapatkanperhatian yang lebih besar dari perencana-perencana pembangunan.     

Genetic Transformation in Haemophilus parainfluenzae Clinical Isolates

Haemophilus parainfluenzae isolates recovered from patients with respiratory diseases were studied for their ability to undergo genetic transformation by isogenic DNA. Two chromosomal markers, streptomycin resistance and nalidixic acid resistance, were tested for transformation efficiencies in H. parainfluenzae recipients from three biotypes. Most efficient in transformation was biotype II, followed by biotype I, while biotype III was nontransformable. Lack of transformation was not owing to poor donor activity of DNA, but to inability of the cells to develop competence. Strains that formed clumps in liquid media were nontransformable. Since the transformable biotype II is one of the prevalent biotypes world wide, one can speculate that DNA transformation probably plays a major role in the spread of drug resistance in H. parainfluenzae. Received: 9 December 1997 / Accepted: 26 February 1998     

The pleiotropic phenotype of Apc mutations in the mouse: allele specificity and effects of the genetic background

Familial adenomatous polyposis (FAP) is a human cancer syndrome characterized by the development of hundreds to thousands of colonic polyps and extracolonic lesions including desmoid fibromas, osteomas, epidermoid cysts, and congenital hypertrophy of the pigmented retinal epithelium. Afflicted individuals are heterozygous for mutations in the APC gene. Detailed investigations of mice heterozygous for mutations in the ortholog Apc have shown that other genetic factors strongly influence the phenotype. Here we report qualitative and quantitative modifications of the phenotype of Apc mutants as a function of three genetic variables: Apc allele, p53 allele, and genetic background. We have found major differences between the Apc alleles Min and 1638N in multiplicity and regionality of intestinal tumors, as well as in incidence of extracolonic lesions. By contrast, Min mice homozygous for either of two different knockout alleles of p53 show similar phenotypic effects. These studies illustrate the classic principle that functional genetics is enriched by assessing penetrance and expressivity with allelic series. The mouse permits study of an allelic gene series on multiple genetic backgrounds, thereby leading to a better understanding of gene action in a range of biological processes.