Hypertension is an important risk determinant for chronic kidney disease: results from a cross-sectional, observational study from a rural population in South India

Hypertension (HTN) is an important cause for chronic kidney disease (CKD). There is a paucity of studies exploring the association of HTN with CKD from rural India. The objective of the study was to determine the prevalence and the determinants for HTN in a rural population in South India, focusing on the association with CKD. In a cross-sectional study on 2984 adults in three villages, demographic and anthropometric data were collected. Blood pressure was recorded on all individuals and prevalence was estimated. Proteinuria, microalbuminuria (MA) and estimated glomerular filtration rate (eGFR) were determined in a subgroup of 1331 subjects and the relation with HTN was analysed. Prevalence of HTN was 30.4% (95% CI 28.75-32.05%). In all, 78.08% had stage 1 HTN while 22% had stage 2 HTN. In total, 27.4% (249/908) subjects were aware of their hypertensive status. Of them, only 14.4% had adequate control of blood pressure. Age>50 years, diabetes, body mass index >25 and eGFR<60 ml min^-1 were independent significant predictors of HTN (P<0.05). HTN was found to be an important risk factor for CKD even after adjusting for age, diabetes and cardiovascular risk factors (OR 2.22, 95% CI 1.46-3.36, P<0.001). The high prevalence of HTN, very low level of awareness and control, and the significant association with kidney disease indicate a need for stronger public health initiative with better penetration for awareness and screening for HTN and CKD in India's villages.

The effect of Emblica officinalis diet on lifespan, sexual behavior, and fitness characters in Drosophila melanogaster

Drosophila is an excellent organism to test Ayurvedic medicines. The objective of our study was to explore the potential of Emblica officinalis drug on longevity, sexual behavior, and reproductive fitness of Drosophila melanogaster using adult feeding method. Increase in the lifespan, fecundity, fertility, ovarioles number, and developmental time was observed in both parents and F1 generation, but not in the F2 generation in experimental culture (control + E. officinalis). According to the Duncan's multiple range test and ANOVA, there is a significant difference between two cultures. It was also noticed that E. officinalis influence some fitness characters in Drosophila along with sexual behavior.

Alteration in haematocrit values and plasma protein fractions during the breeding cycle of female pigeons, Columba livia

Haematocrit measurements and plasma protein electrophoresis were carried out in female pigeons (Columba livia) during the breeding cycle. Non-laying birds showed higher (p < 0.001) haematocrit values than those involved in courtship and mating, nest-building, incubation and feeding and brooding. Significant differences in relative percentage of various plasma protein fractions were observed as a function of breeding. Haematocrit could be a useful index to the non-laying status of pigeons like that in chickens, Gallus domesticus.

Mating success of males with and without wing patch in Drosophila biarmipes

Some males of D. biarmipes--synonym of D. rajasekari and D. raychaudhuri have a black patch on the wing. The patch extends from the apical margin of wing to the third longitudinal vein. Field and laboratory studies have been carried out in D. biarmipes to study role of male's wing patch in mating success. The field study shows that nature favors D. biarmipes males with patch. Although males without patch mated, males with patch have higher mating success suggesting the role of wing patch during courtship. Further, among mating males, males with patch had longer wings than males without patch. During courtship, males with patch oriented and mated faster; performed courtship acts such as tapping, scissoring, vibration, licking and twist dance more times than males without patch in both competitive and non-competitive situations. The results indicate that there is a casual relationship between the presence of wing patch, mating speed and success. Also there is a correlation between presence of wing patch, size of the flies and mating success.

Cryopreservation of the endangered mahseer (Tor khudree) spermatozoa: I. Effect of extender composition, cryoprotectants, dilution ratio, and storage period on post-thaw viability

Several in situ and ex situ conservation strategies have been suggested for the revival of stocks of Tor khudree (Sykes), a threatened species. Cryopreservation of spermatozoa is crucial for the conservation of stocks of endangered species so that sustainable production can be ensured. Among the different extenders, modified fish Ringer (E1) was found to be the best for cryopreservation of T. khudree spermatozoa. Extender E2 appeared the next best. Extenders based on chicken egg yolk and milk powder were found to be unsuitable for the cryopreservation of T. khudree spermatozoa. Among the cryoprotectants, dimethyl sulfoxide provided maximum protection to spermatozoa during freezing and thawing. Propylene glycol and methanol were found to be less effective. Of the four spermatozoa dilutions, 1:10, 1:15, and 1:20 showed better motility rates than 1:5. At the former dilution ratios, the motility rates which were more than 95% prior to freezing were reduced to 80-81 and 43-67%, 10 and 70 days after cryopreservation, respectively. The motility duration did not differ much with increasing storage period at all the dilution ratios. Motility rates generally decreased with an increase in frozen storage. When spermatozoa were thawed and stored at 25 degrees C for varying periods, motility percentage, and duration decreased gradually as the storage period increased; spermatozoa stored up to 40 min after thawing retained 55% motility and were motile up to 77s; these values declined further leading to the complete cessation of motility 70 min after storage. The importance of extender-cryoprotectant mixture, milt dilution, and storage period in developing a protocol for T. khudree spermatozoa cryopreservation is discussed.

Blood profile of pigeons (Columba livia) during growth and breeding

Changes in the blood profile of domestic pigeons (Columba livia) were studied during growth and breeding cycle. Counts of erythrocytes and leucocytes, and values of mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), blood volume, plasma volume (BV), width of erythrocytes, and length, width and volume of erythrocyte nuclei of squabs almost reached adult values by the 4th week of age. During courtship and mating, while the level of plasma glucose increased, those of albumin, potassium, cholesterol, calcium and uric acid decreased. At nest-building, plasma albumin and plasma calcium increased significantly. The initial phase of incubation showed an elevation in plasma calcium and a decline in cholesterol and sodium, whereas mid-phase of incubation indicated a marked rise in cholesterol and uric acid. Terminal phase of incubation had significantly low plasma protein level. During feeding and brooding period, a significant rise in sodium, protein and glucose levels and a fall in calcium were observed. Following egg-laying, there was a significant rise in calcium and a drop in protein, haemoglobin, cholesterol, sodium and MCH values. Concomitant with the phenomenal rate of growth of squabs, their haematological indices neared adult values by the 4th week of age and during breeding activity significant changes in blood values occurred.

Acute renal failure secondary to rhabdomyolysis following near-drowning in sea water

We report here a rare case of acute renal failure following near-drowning in sea water. A 21-year old college student presented in acute renal failure 48 hours after a near-drowning event. Investigations revealed rhabdomyolysis to be the cause of renal failure.

Differential metabolism of alprazolam by liver and brain cytochrome (P4503A) to pharmacologically active metabolite

Cytochrome P450 (P450) is a superfamily of enzymes which mediates metabolism of xenobiotics including drugs. Alprazolam, an anti-anxiety agent, is metabolized in rat and human liver by P4503A1 and P4503A4 respectively, to 4-hydroxy alprazolam (4-OHALP, pharmacologically less active) and alpha-hydroxy alprazolam (alpha-OHALP, pharmacologically more active). We examined P450 mediated metabolism of alprazolam by rat and human brain microsomes and observed that the relative amount of alpha-OHALP formed in brain was higher than liver. This biotransformation was mediated by a P450 isoform belonging to P4503A subfamily, which is constitutively expressed in neuronal cells in rat and human brain. The formation of larger amounts of alpha-OHALP in neurons points to local modulation of pharmacological activity in brain, at the site of action of the anti-anxiety drug. Since hydroxy metabolites of alprazolam are hydrophilic and not easily cleared through blood-CSF barrier, alpha-OHALP would potentially have a longer half-life in brain.

Variability of morphological traits in Drosophila bipectinata complex

Phenotypic or morphological differences among different populations and sexual dimorphism in certain metric traits were analysed in D. bipectinata complex. It was noticed that different populations of D. bipectinata species group harbour large amount of variation for these characters. In all the populations, morphometric characters such as lengths of femur, tibia and wing length, wing width, number of sternopleural bristles and bristles on epandrium varied significantly among populations. The study indicates that the morphological variations are due to the interplay of genetic and environmental endowments. Further, females had significantly larger values, for lengths of femur, tibia and wing length, wing width and sternopleural bristles.

Bottleneck effect on intra- and interspecific competition in Drosophila malerkotliana

Intra and interspecific competition experiments involving control and bottleneck lines of monomorphic and polymorphic populations of D.malerkotliana with D.nasuta nasuta have been carried out. Productivity and population size were evaluated in these lines. The results show that control line had higher relative fitness and adaptedness (productivity and population size) under both intra and interspecific competition than their respective bottleneck lines and D.nasuta nasuta. This indicates that bottlenecks have an effect on competition in D.malerkotliana. The consequence of such competition studies using control and bottleneck lines of D.malerkotliana and D.nasuta nasuta is discussed.

Body size, mating success and advantage of large flies in Drosophila bipectinata species complex

Mating success of large and small flies of Drosophila malerkotliana and D. bipectinata was studied using multiple, male and female choice methods. In multiple choice method the large male mated with large female and small male paired with small female. In female choice method, large male was successful in mating with female irrespective of its size while in male choice method, preferential mating occurred between large male and large female as well as small male and small female. The consequence of such non-random mating in the presence of male rivarly and preferential mating has been discussed.

Size-assortative mating in Drosophila malerkotliana

The relationships between wing size, locomotor activity, mating latency, courtship pattern and mating success (total number of pairs mated in a given time unit) were studied in pairs of Drosophila malerkotlianaMating latency was negatively correlated with wing length and with locomotor activity while wing length and locomotor activity were positively related. In trios of a female and a long-winged and a short-winged male, long-winged males mated more successfully than short-winged males. In trios of a male and a long-winged and a short-winged female, long-winged males mated with long-winged females, and short-winged males with short-winged females. In addition, in pairs of long-winged/short-winged flies, long-winged flies courted and mated more successfully than short-winged flies.

Effect of bottlenecks on incipient sexual isolation, mating activity and fertility in Drosophila malerkotliana

Effect of bottleneck sizes, on sexual isolation, mating speed and fertility were studied in D. malerkotliana established from natural population. After 10 generations of laboratory breeding, flies showed incipient sexual isolation between control line and some bottleneck lines and also between bottleneck lines. These findings do not fully agree with the general assumption that the establishment of bottlenecks accelerates speciation. The courtship latency and mating speed increases with increasing size of bottlenecks whereas copulation duration and fertility decreases with increasing bottleneck size. There was no sign of rebounding in fitness with in 10 generations as observed by Bryant et al. in house flies.

Carbohydrates of pigeon milk and their changes in the first week of secretion

The carbohydrate content of pigeon crop secretion called pigeon milk (PM) was in the range of 0.9-1.5%. Sugars of trichloroacetic acid soluble (TCA-S) fraction increased by 67% between day-1 and day-5 of secretion while those of TCA- insoluble (TCA-P) fraction remained fairly constant. Sialic acids constituted 5-9% of carbohydrates. The proportion of lipid- and protein-bound sialic acids was 51% and 31% respectively; the former increased from 41% to 68% between day-1 and day-5 whereas the latter decreased from 45% to 21% during the corresponding period. Some of the sugars of PM were fucose (40%), glucosamine (31%), galactose (12%), mannose (9%) and glucose (8%). The free sugars whose content was very low (0.05%) included fucose, mannose, glucose and some unidentified oligosaccharides. The proportion of lipid- and protein-bound sugars was 31% and 63% respectively; the former decreased by 7% from day-1 to day-5 while the latter increased by 11% during the same period. Gel chromatography of PM confirmed the presence of sialic acids and glucosamine; the latter existed both in free and bound form. The nature of changes in the carbohydrate composition of PM in the first week of secretion was more quantitative than qualitative.

In vivo and in vitro growth-stimulatory effects of pigeon milk

Pigeon milk (PM) was tested for its effect on growth in vivo and in vitro. Eleven-day-old mice sucklings given a supplementary feeding of 125 mg PM per day for 3 days showed a significant increase in the weight of stomach and distal intestine, and the length of small intestine; there was, however, a significant decrease in heart size. In PM-fed animals the protein content of stomach, and RNA content of stomach, caecum and distal intestine increased whereas protein content of testes and distal intestine and DNA content of stomach decreased. Crude homogenates of PM stimulated 3H-thymidine incorporation both in quiescent mouse embryo fibroblasts and Chinese hamster ovary cells. Addition of PM homogenates to cell cultures increased cell number but not protein content. The extent of in vitro growth-stimulation by 1% (v/v) PM homogenate was comparable to that by 2% (v/v) foetal bovine serum but was greater than that by 0.1 ng mouse epidermal growth factor. It appears that in mammalian test systems the in vitro growth-stimulatory effects of pigeon milk outweigh those observed in mice.

Pigeon milk: a new source of growth factor

Crude, partially purified and purified fractions of pigeon milk injected subcutaneously in newborn mice brought about precocious opening of eyelids by 2-3 days and eruption of incisors by 3-4 days. The biological activity of pigeon milk-derived growth factor (PMGF) compared well with that of mouse epidermal growth factor (mEGF).

Studies on the growth-stimulatory activity of pigeon milk--comparison and synergistic effects with serum

Pigeon milk, a nutritive secretion from the crop of breeding pigeons, was tested (on v/v basis) for growth factor activity either separately or in combination with other growth supplements. Synthesis of DNA in confluent monolayers of quiescent Chinese hamster ovary cells was enhanced by the homogenates of pigeon milk in the presence of both fetal bovine serum and bovine serum albumin, although the response with fetal bovine serum was greater than that with bovine serum albumin. The in vitro growth stimulation by pigeon milk was also reflected in the increase in cell number. Specific activity of pigeon milk growth factor, measured against both Chinese hamster ovary cells and mouse embryo fibroblasts, was found to be higher than that of fetal calf serum, fetal bovine serum, and goat, horse, pig and human serum. The growth-stimulatory property of pigeon milk did not change in the first 5 days of its secretion.

Regional differences along the small intestine of the pigeon (Columba livia): histobiochemical evidences

Mucosal surface area, protein, DNA and RNA content, [3H]-thymidine incorporation, total activity of glucosidases, peptidases, phosphatases and transaminases were measured in the duodenum and in the middle and lower parts of the small intestine of the domestic pigeon Columba livia. Mucosal surface area, protein, nucleic acid content and [3H]-thymidine incorporation were significantly higher in the duodenum and in the middle part of the small intestine than in the lower part. Whereas the activities of alkaline phosphatase, sucrase, cellobiase and lactase were significantly higher in the middle part of the small intestine, those of maltase, glucoamylase and leucine aminopeptidase were significantly higher in the lower part. It is concluded that in Columba livia small intestine, regional differences are more pronounced between the middle and the lower parts of the small intestine than between this middle part and the duodenum.

In vitro growth-stimulatory property of pigeon milk

Five cell lines were employed to test the growth-stimulating property of pigeon milk in vitro. All the cell lines except A431 showed good growth response to crude homogenates of pigeon milk. Enhancement of DNA synthesis in quiescent Chinese hamster ovary (CHO) cells by pigeon milk was dose dependent up to a concentration of 1%. In vitro growth stimulation by 1% pigeon milk was approximately equal to that by 2% foetal bovine serum (FBS) when CHO cells were used, growth stimulation of Vero cells by 1% pigeon milk was roughly three times of that by 2% FBS. In contrast, 1% pigeon milk was only half as active as 2% FBS on NIH/3T3 cells and five times less active than 2% FBS on human foetal lung fibroblast cells. After dialysis using a relative mass (M(r)) cutoff of 3500, the pigeon milk mitogenic activity was retained in the dialyzed solution, although it decreased by 40-60% when dialyzed with M(r) cutoffs of 8000 and 12,000-14,000. The growth-stimulating activity of pigeon milk was resistant to heat, acid, alkali, and the action of urea, guanidine hydrochloride, dithiothreitol, and trypsin. We suggest that pigeon milk is a new source of growth factor(s) capable of stimulating in vitro the growth of many mammalian cell types.

Lack of correlation between mating activity and EST-1 polymorphism in three natural and laboratory populations of Drosophila bipectinata

Est-1 polymorphism and mating activity have been studied in three natural populations of D. bipectinata and after 10 generations of their maintenance in the laboratory. The results indicate that the enzyme Est-1 variation was not significant within natural populations within F10 generation and also between different natural populations and F10 generation indicating the role of balancing selection in the maintenance of enzyme polymorphism in both natural and laboratory conditions. On the other hand, there was variability in the mating activity within natural populations and within F10 generation and also between natural population and F10 generation. However, there was no correlation between Est-1 polymorphism and mating activity.

Purification of a growth factor from pigeon milk

Aqueous extracts of pigeon milk (PM) stimulated the in vitro growth of quiescent CHO cells maintained in culture and caused precocial incisor eruption and eyelid opening in newborn mice. CM-cellulose chromatography of the growth factor of PM enhanced its biologic activity. Rechromatography of CM-active fractions in DEAE-cellulose columns yielded a single peak that was mitogenic both in vivo and in vitro. SDS-PAGE of DEAE-active fractions gave rise to a single band of molecular weight about 6000. This protein, termed as pigeon milk-derived growth factor (PMGF), yielded a single peak on gel filtration in Sephadex G-100 columns. Elution pattern of PMGF was similar to that obtained for epidermal growth factor of mouse submaxillary gland (mEGF). The chromatographic plus electrophoretic pattern, and biologic action of PMGF suggest it to be a EGF-like protein.

Correlative studies on mating speed and metric traits in Drosophila malerkotliana

Relationship between mating speed, an important component of fitness, and morphological characters such as lengths of wing, femur, tibia and first tarsus have been analysed in D. malerkotliana. Flies mating first have longer wings and forelegs and mating flies have lower coefficient of variability in wing length than nonmating ones. Age seems to have no detectable effect on the relationship between these metric traits and mating speed.

Stimulatory effect of pigeon milk growth factor on protein and nucleic acid synthesis in neonate mice

Effect of subcutaneously administered pigeon milk-derived growth factor (PMGF) on protein and nucleic acid content of various body organs was studied in neonate mice. Although the body and organ weights of PMGF-treated mice did not differ from those of controls, the weight of testes was significantly higher in the former than the latter. The treated animals had significantly greater content of protein (in liver and skin), DNA (in liver, lung, stomach, duodenum, ileum and rectum) and RNA (in liver, stomach, ileum and skin). The protein/DNA ratio was lower in many organs of PMGF-treated mice. These results indicate that the biological properties of PMGF bear semblance to those of epidermal growth factor isolated from mouse salivary gland and human milk.

Observations on bacteria associated with pigeon crop

Lactobacilli, streptococci and coliforms of pigeon crop contents, 5th wash, macerate and those of first-day pigeon milk have been studied. Streptococci predominated in all the samples tested. Relatively higher counts of lactobacilli and streptococci in crop macerate than in the 5th wash suggested the adhesion of these bacteria to crop wall. Because of frequent occurrence in crop of partially digested fibrous food, its contents were tested for the presence of cellulolytic bacteria. The results indicated that four isolates were capable of utilizing cellulose with the resultant production of reducing sugars. It is inferred that the crop microflora is involved in the degradation of dietary fibre in the pigeon.

Differential effects of harmaline and ouabain on intestinal glucose transport in the pigeon

Effects of harmaline and ouabain on intestinal transport in vitro of D-glucose in the pigeon are investigated. Harmaline inhibits glucose influx and affects intestinal Na+-K+-ATPase activity though the substrate uptake is more sensitive than the enzyme activity. Low concentration of harmaline while drastically inhibiting glucose uptake, does not affect intracellular concentration of Na+ and K+. In contrast, ouabain, though has no significant effect on glucose uptake, alters substantially the ionic balance of cells. Harmaline also affects that component of nutrient influx which is left unaffected by ouabain. Mucosal-serosal flux of glucose is reduced by harmaline when it is present only on the mucosal side of everted intestinal sacs. On the contrary, similar effect is produced by ouabain when it is placed only on the serosal side. It appears that harmaline possibly inhibits glucose transport in the pigeon intestine by two ways: first, by irreversible binding Na+-K+-ATPase - a feature shared by ouabain, and second, by reversible binding Na+-binding sites of enterocyte membrane - an effect not shared by ouabain.

Studies on the intestinal disaccharidases of the pigeon IV. Immunochemical properties of sucrase . isomaltase and maltase . glucoamylase

Antisera against purified pigeon small intestinal sucrase-isomaltase (S-I) and maltase-glucoamylase (M-G) were prepared from rabbits. Both sera showed cross-reactivity. It was demonstrated that the sucrase . isomaltase was purified to homogeneity, supporting our earlier results of SDS-PAGE of pigeon intestinal disaccharidases. Both the sucrase- isomaltase and maltase-glucoamylase activities were not inhibited by either specific or cross-reacting antibodies even when a several fold of either antibody was present. It is inferred from these immunochemical results that the two complexes in the pigeon intestine share many structural identities, and that their catalytic site(s) may not be involved in their antigenic domains.

Studies on the intestinal disaccharidases of the pigeon. III. Separation, purification and properties of sucrase-isomaltase and maltase-glucoamylase

Sucrase-isomaltase (S-I) and maltase-glucoamylase (M-G) of the brush border have been purified to electrophoretic homogeneity from the pigeon small intestine. Heat-inactivated enzymes of crude homogenates of the pigeon intestinal mucosa, papain-solubilized enzymes and those obtained after chromatographic fractionation behaved in an identical manner. Depending on their sensitivity to heat treatment, the disaccharidases were identified to consist of two maltases; one, the heat-labile maltase, and the other, the heat-stable maltase. Sucrase and isomaltase constituted the thermolabile maltase and could be distinguished from each other. Maltase and glucoamylase formed the thermostable maltase the activities of which however, remained inseparable. Based on these results and in accordance with the nomenclature suggested by Dahlqvist & Telenius (1969), the pigeon intestinal disaccharidases were classified as follows: Maltase Ia = isomaltase, Maltase Ib = sucrase, and Maltase II = glucoamylase. DEAE-Cellulose chromatography did not resolve the two enzyme complexes but gel filtration of the active fractions recovered from the former step, resulted in their separation into two distinct peaks. Sucrase, isomaltase and a part of the maltase activity were recovered in the first peak which eluted close to the void volume. Glucoamylase and the remaining maltase activity were recovered in the second peak which appeared to have been retarded on the column because they were eluted much more slowly. The S-I and M-G complexes have an apparent molecular weight of 195 kd and 209 kd as determined by their gel-filtration pattern on Sepharose 6B. S-I hydrolysed alpha-glucosides such as maltose, sucrose and palatinose with a Km of 3.12 mM, 8 mM and 8.36 mM respectively and did not attack starch or dextran. In contrast, M-G catalysed the hydrolysis of starch, amylose and maltose with a Km of 3.12 mM, 7.59 mM and 3.52 mM respectively, and had no action on sucrose or palatinose. Both S-I and M-G were glycoproteins, and were inhibited by Ag+, Hg2+ and Tris but not by p-hydroxymercuribenzoate, iodoacetamide or imidazole. Na+ on the other hand activated both the enzyme complexes by about 20-25%. It is suggested that the molecular and catalytic properties of intestinal disaccharidases of pigeons do not differ considerably from those of Mammals.

Studies on the intestinal disaccharidases of the pigeon. II. Subcellular localization and solubilization

In the pigeon, 70-80% of the activities of maltase (alpha-D-glucoside glucohydrolase EC 3.2.1.20), sucrase (alpha-glucohydrolase, EC 3.2.1.48), isomaltase (dextran 6-alpha-D-glucan hydrolase, EC 3.2.1.10) and glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) were found to be localized in the brush-border membrane of intestinal epithelial cells. Of the total glycosidase activities in the mucosal homogenate, nearly 60 to 70% were recovered in the microsomal (105 000 X g) fraction, about 30% in the mitochondrial (22 000 X g) fraction and less than 5% from the cytosol (105 000 X g supernatant) fraction. The hydrolases were solubilized by digestion with papain but not with trypsin, and the phosphate ion had a protective effect in the solubilization. Amongst detergents, Triton X-100 but not sodium deoxycholate, was found to truly solubilize these enzymes.

THe effects of the gut microflora and dietary fibre on energy utilization by the chick

1. Groups of adult colostimized chickens were given diets with and without dietary fibre in the form of bagasse or wheat straw. The fibrous materials were analysed for their contents of cellulose, hemicellulose and lignin. The digestible energies (DE) and metabolizable energies (ME) of these diets were measured by a balance method. 2. Groups of germ-free and conventional chicks aged 4 weeks were given diets with and without penicillin or with and without graded levels of wheat straw as a source of fibre and the ME of these diets were determined. 3. The incorporation of the forms of dietary fibre tested reduced the DE and the ME of the diets in adult conventional chickens and the ME in young germ-free and conventional chicks. Both DE and ME were reduced in proportions that suggested that the dietary fibre present was acting largely as an inactive diluent of the dietary energy and was not affecting the absorption of other nutrients. In the young germ-free and conventional chicks, there was a linear relationship between the proportion of wheat straw in one diet and the reduction ME. 4. Dietary penicillin did not alter the ME of the diet in either the germ-free or the conventional environments. 5. The reduction of ME with incorporation of wheat straw was less in conventional than in germ-free chicks. It is suggested that this may be due to the ability of chicks with a gut flora to obtain a small amount of energy from wheat straw.

Studies on mating behaviour in the Drosophila bipectinata complex

Courtship and mating behaviour were studied in six species and subspecies of the bipectinata complex of the melanogaster species-group of Drosophila. Species relationships inferred from the present behavioural observations were compatible with interrelationships inferred from studies on polytene chromosomal synapsis and allozymes by earlier workers. Thus D. bipectinata, D. parabipectinata and D. malerkotliana are more closely related to one another than to D. pseudoananassae, and D. bipectinata and D. parabipectinata are more closely related to each other than to D. malerkotliana.

The effects on chicks of dietary fibre from different sources: a growth factor in wheat bran

1. Groups of chicks were given a low-residue diet with or without supplements of dietary fibre in the form of wheat bran, wheat straw or bagasse. Growth and food conversion efficiency (g weight gained/g food eaten; FCE) during the first 4 weeks of life were measured. 2. In every one of seven experiments supplementation of the diet with 100 g wheat bran/kg resulted in improved growth, and in three experiments FCE was also increased. 3. Supplementation with coarsely-milled wheat straw to provide an amount of unavailable carbohydrate equivalent to that in the bran diet resulted in poorer growth; finely-milled wheat straw had little effect on growth. 4. The growth-promoting effect of bran was destroyed by sterilization with heat or gamma-radiation. 5. In some experiments weights, lengths and volumes of small intestines were measured. Differences in intestinal dimensions between birds given the diet with and without fibre were not consistent, nor were they correlated with growth rate or FCE. 6. Histometric observations on small intestines from a few birds indicated that those given coarse wheat straw had longer vili and thicker muscularis layers, and the caecal tonsils had a greater area of lymphoid tissue and more follicles.

Measurement of digestible and metabolizable energy of diets for rats

A balance method for the measurement of digestible and metabolizable energy in rats is described. Experimentally determined metabolizable energies of 2 diets for rats were closer to those values for metabolizable energy calculated from tabulated values for pigs rather than chickens. Some drawbacks in the use of tables of energy values to predict the energy of diets are discussed.