Functional response of pacific damsel bug,Nabis kinbergii [Hemiptera: Nabidae]

The functional responses of adult and 5th instar Pacific damsel bug,Nabis kinbergii Reuter were determined under laboratory conditions using Australian crop mirid,Sidnia kinbergi (Stal), and pea aphid,Acyrthosiphon pisum (Harris) as prey.Holling's (1959) type II equation was found to adequately define the functional response of this predator except when 5th instar nymphs were provided with Australian crop mirid as prey. In this instance, a type III response was found.      

Embryo rescue and plant regeneration in vitro of selfed chickpea (Cicer arietinum L.) and its wild annual relatives

The main constraint to the transfer of desired traits into cultivated chickpea from wild Cicer relatives is the presence of post-zygotic barriers which result in abortion of the immature embryo following interspecific hybridisation. Rescue of hybrid embryos in vitro and regeneration of hybrid plantlets could allow chickpea breeders to transfer desirable traits from wild relatives of chickpea. The development of embryo rescue techniques using selfed chickpea and selfed wild relatives is being used as a first step to protocols for wide hybrids. Optical microscopy studies of embryogenesis, in both selfs and hybrids, identified deleterious changes in the fertilised hybrid seed as early as 2–4 days after pollination in some crosses. These observations suggest that the appropriate time to rescue chickpea × C. bijugum hybrids is at the early globular stage of embryogenesis (2–7 days old), which requires the development of a complex tissue culture medium. In contrast hybrids between chickpea × C. pinnatifidum abort later (up to 15–20 days old) at the heart-shaped or torpedo stages, and are easier to rescue in vitro. Genotype also plays a significant role in the ability of immature selfed ovules to germinate in vitro. In this paper we report on the optimisation of␣protocols for rescueing immature embryos using selfed chickpea and its wild relatives in ovule, and subsequently to regenerate plantlets.     

Correction to: Combined therapeutic efficacy of carvacrol and X-radiation against 1,2-dimethyl hydrazine-induced experimental rat colon carcinogenesis

Molecular and Cellular Biochemistry -     

Increase in Sensitivity for the Assay of Neomycin in Milk

A study was conducted to design a more sensitive and flexible technique for the assay of neomycin in milk. Sterile Antibiotic Assay medium (Difco; 15 ml) was poured into glass petri dishes with aluminum tops equipped with absorbent discs. Seed agar (4 ml; containing 1% sodium chloride) inoculated with standardized amounts of the test organism (Staphylococcus epidermidis ATCC 12228) was laid over the hardened base agar, and stainless-steel cylinders were placed equal distances apart in the agar. The plates were refrigerated for 30 min and the cups were removed in an atmosphere of minimal contamination. The resultant holes were sealed with melted agar. After preparation, the holes were used for assay procedures. Samples to be assayed were pipetted into the holes and the plates were refrigerated for 90 min at 4 C. Plates were incubated for 18 to 20 hr at 32 C. The zones of inhibition were recorded and compared with a standard curve. The approximate sensitivity of this method was 0.05 mug/ml.     

Type II hereditary angio-oedema associated with two mutations in one allele of the C1-inhibitor gene around the reactive-site coding region.

The polymerase chain reaction and nucleotide sequence analysis have been used to characterise two point mutations in the eighth exon of one allele of the C1-inhibitor gene in a kindred with type II hereditary angio-oedema (HAE). The mutations comprise a G to A substitution at C1-inhibitor gene nucleotide 16789 and an upstream C to T substitution at nucleotide position 16765. This represents the first report of these two mutations in the same C1-inhibitor allele in type II HAE. The molecular genetic pathogenesis of HAE is discussed in the light of these findings.     

Albinism in Plants: A Major Bottleneck in Wide Hybridization,Androgenesis and Doubled Haploid Culture

Albinism is a common problem encountered in interspecific crosses and tissue culture experiments including anther culture and generation of doubled haploids. It is characterized by partial or complete loss of chlorophyll pigments and incomplete differentiation of chloroplast membranes. This in turn impairs photosynthesis and the plants eventually die at a young stage without reaching maturity. Environmental conditions such as light, temperature, media composition and culture conditions play some role in determining the frequency of albino plant formation. Genetic factors are even more important, and are major determinants in albinism. Genetic studies in different crops show that it is a recessive trait governed by many loci. Both the nuclear and chloroplast genomes affect albinism and incompatibilities between the two are a probable cause of many pigment defects in hybrid progenies. Such incompatibility has been reported in a large number of angiosperms. The mechanisms behind these incompatibilities are poorly understood. Studies of plastid DNA inheritance together with observations using electron microscopy have established that the transmission of plastids can be maternal, paternal or biparental, even within the same genus, especially following wide crosses; contrary to the widespread belief that plastids are almost always transmitted from the maternal parent. Albinism has been overcome in some crop species through somatic hybridization and development of cybrids (cytoplasmic hybrids). However, the strict requirement of efficient protoplast regeneration is a major limitation of these techniques. This review focuses on albinism following interspecific crosses or development of doubled haploids facilitated by tissue culture experiments, underlying mechanisms, and the possibilities for dealing with this important biotechnological limitation.