Production of secondary metabolites by solid-state fermentation

Microbial secondary metabolites are useful high value products that are normally produced by liquid culture; but could be advantageously produced by solid-state fermentation (SSF). Particularly if SSF could benefit from a deeper understanding of microbial physiology in a solid environment. Recent research indicates that different kind of secondary metabolites can be produced by SSF: antibiotics, phytohormones, food grade pigments, alkaloids, etc. Physiology in SSF shows several similarities with physiology in liquid medium, so similar strategies must be adapted for efficient processes. However, there are certain particularities of idiophase in solid medium which dictate the need for special strains.

Effect of particle size, packing density and agitation on penicillin production in solid state fermentation

The use of a large particle size (14 mm) support (sugar cane bagasse) increased penicillin production by solid state fermentation by 37 %, however this effect was due to a higher sugar concentration in this bagasse fraction. Cultures with closer packing densities (0.35) produced 20 % more penicillin. Agitation did not have a negative effect on production if moisture loss during the operation is restituted.

Effects of seasonal ambient heat stress (spring vs. summer) on physiological and metabolic variables in hair sheep located in an arid region

Twenty Dorper × Pelibuey primiparous ewes were used to evaluate effects of seasonal ambient heat stress (i.e., spring vs. summer) on physiological and metabolic responses under production conditions in an arid region. Ten ewes experiencing summer heat stress (i.e., temperature = 34.8 ± 4.6 °C; THI = 81.6 ± 3.2 units) and 10 under spring thermoneutral conditions (temperature = 24.2 ± 5.4 °C; THI = 68.0 ± 4.8 units) were corralled together to measure rectal temperature, respiratory frequency, and skin temperatures at 0600, 1200, 1800, and 2400 h on four occasions over 40 days. Blood metabolite and electrolyte concentrations were also measured at 0600 and 1800 hours. Data were analyzed with a completely randomized design using repeated measurements in time. Rectal and skin temperatures, as well as respiratory frequency, were higher (P < 0.01) in summer than spring at all measured days. Blood serum glucose, cholesterol, triglycerides, and chlorine concentrations were lower (P < 0.01) in summer than spring at 0800 and 1800 hours. In contrast, summer heat stress increased (P < 0.01) blood urea and potassium concentrations at 0800 and 1800 hours. Compared with spring thermoneutral conditions, summer heat stress affected the physiological and metabolic status of hair breed ewes in an arid region, which included blood metabolite and electrolyte adjustments to efficiently cope with summer heat stress.

Overproduction of rifamycin B by Amycolatopsis mediterranei and its relationship with the toxic effect of barbital on growth

A novel method for selecting overproducing strains of rifamycin B was developed. This technique involves the use of lysozyme and the effect of barbital on the growth of A. mediterranei. Complete medium added with glycine and barbital was inoculated with mutagenized mycelium, incubated for 48 hours and treated with lysozyme. The lysozyme resistant mycelium was washed with dilute detergent. Complete medium with glycine but without barbital was inoculated with the washed mycelium. Protoplasts were obtained and regenerated and the colonies were picked and seeded on Bennet agar plates with and without barbital. Two selected mutants were sensitive to 0.5% barbital producing 200% more rifamycin than the parental strain. In addition, 30 barbital resistant mutants were isolated and their production level was lower than the one observed with the parental strain. These results suggest that the effect of barbital on secondary metabolism (rifamycin production) is related to its effect on primary metabolism.

Development of high penicillin producing strains for solid state fermentation

Penicillin production with an industrial strain and 4 strains of P. chrysogenum, in solid state fermentation (SSF) and liquid submerged fermentation (LSF), was determined. Their ability to produce the antibiotic in SSF in relation to their capacity to do so in LSF was evaluated. this was done by calculating the ratio PS/PL (production in SSF/production in LSF), which was called relative production. Clones were isolated from each strain and evaluated in a similar way. The strains presented different relative productions (from 1.4 to 2.5). Within the clones, a much wider range of relative productions was observed (0.6 to 16.7). On the other hand, the highest-producing strains in LSF were also the highest producers in SSF. This indicates that the production potential of a strain is an important factor in its production level in SSF. Moreover, the highest penicillin producing ciones (9,500 to 10,500 microg of penicillin/g were generated from high-yielding strains (P2 and ASP-78). However, the higher-producing strains (in LSF) showed lower relative performance, suggesting that higher producing strains tend to express less efficiently their potential in SSF. In this study, several overproducing clones, particularly suited for SSF, were obtained by the procedures followed. Production increases of 500 to 600 %, in this culture system, were achieved.

Artificial long-day photoperiod in the subtropics increases milk production in goats giving birth in late autumn

Two experiments were conducted to determine whether exposure to a photoperiod of artificial long days in autumn increased milk yield in subtropical goats milked once (Exp. I) or twice daily (Exp. II). In Exp. I, starting at d 10 of lactation, 1 group of does was kept under naturally decreasing photoperiod (DD1X; n = 8), whereas the other group was submitted to an artificial photoperiod of long days (LD1X; n = 8; 16 h light:8 h darkness). The kids were weaned 28 d after parturition, and dams were manually milked once daily. Milk yield and milk components (fat, protein, and lactose) were assessed up to 140 d of lactation. From d 0 to 28 of lactation (suckling phase), mean daily milk yield did not differ between DD1X and LD1X goats (2.3 ± 0.2 kg vs. 2.4 ± 0.2 kg; P = 0.717). However, between d 29 and 84 (early milking phase), mean daily milk yield was greater in LD1X does than in DD1X does (2.6 ± 0.1 kg vs. 2.1 ± 0.1 kg; P = 0.001). Finally, between d 85 and 140 (late milking phase), mean daily milk yield was greater in LD1X goats than in DD1X goats (P ≤ 0.05) only during the first 2 wk. In Exp. II, one group of goats was exposed to a photoperiod of naturally decreasing days (DD2X; n = 8) and another group was submitted to an artificial photoperiod of long days (LD2X; n = 7). In both groups, kids were weaned on d 28 of lactation and the dams were manually milked twice daily. During the nursing phase, mean daily milk yield did not differ between the DD2X and LD2X groups (2.5 ± 0.3 kg vs. 2.6 ± 0.2 kg; P = 0.767). In the early milking phase, mean daily milk yield was greater in LD2X than in DD2X goats (3.3 ± 0.2 kg vs. 2.8 ± 0.2 kg; P = 0.022), whereas during the late milking phase, milk yield did not differ between the 2 groups (P = 0.946). In both experiments, milk composition was not significantly influenced by exposure to long-day photoperiod. We conclude that, in subtropical female goats that start lactation in late autumn, exposure to an artificial long-day photoperiod stimulates milk yield, even if goats are milked once daily. In addition, combining exposure to long days with twice-daily milking will increase further milk yield in such goats without affecting milk components.

Respiration studies of penicillin solid-state fermentation

An earlier work showed that when the bagasse content (BC) of the solid medium was decreased within a wide range of values, penicillin production by solid-state fermentation was always increased. Respiration studies were performed to understand how BC controls the secondary metabolism in this culture system. CO2 production of solid cultures with different compositions was monitored. In cultures of series A, the initial moisture content was increased and this variation was compensated by decreasing the nutrient and BC of the medium. In series B the initial moisture content was increased while BC was decreased and the nutrient content increased. In addition, penicillin production and respiration was also studied in extreme media (dry and concentrated and humid and diluted), with high and low BC. Criteria for the interpretation of respiration kinetics of the idiophase were established for the first time in this work. For the cumulative form (total CO2/g dry matter vs t) as well as for derivative (CO2/g dm/h vs t) respiration kinetics, the CO2 production rate (Q(CO2)) was determined by calculating the slope of the cumulative curve. Results indicate that Q(CO2) of the tropho- and idiophases was directly related to the BC of the solid medium (and inversely related to penicillin yields). These conclusions were confirmed by analysis of the derivative form, the results of which indicate that a lower but stable metabolic activity is essential for obtaining high penicillin yields in solid-state fermentation (SSF). The results indicate that the derivative CO2 production kinetics proved to be a more precise and sensitive indicator of the culture metabolic activity during idiophase than the cumulative respiration kinetics.

Antiresorptives and anabolic therapy in sequence or combination for postmenopausal osteoporosis

Osteoporosis is a chronic disease which may require treatment for many years and requires not only individual management but often sequential or combination treatments. Monotherapy with antiresorptives is usually the first choice. Sometimes, it is necessary to modify this option for therapeutic failure or for the time of use and risk of side-effects. Due to their different mode of action, therapy with anabolic drugs has increased our options in the treatment of osteoporosis. Postmenopausal women and men with severe and progressive osteoporosis despite antiresorptive treatment ('therapeutic failure') should be evaluated for treatment with an anabolic option. Moreover, anabolic agents are indicated for 18-24 months in patients at high risk. Then, sequential antiresorptive therapy is recommended to maintain drug increases in bone mass and support secondary mineralization of the newly formed bone. Combination therapies of antiresorptives and anabolic agents have shown a significant increase in bone mineral density compared to monotherapies. However, none of the combinations have been studied for the prevention of fractures. Combination therapy may not be recommended because of the possible increase in cost.

CD38: From Positive to Negative Expression after Daratumumab Treatment

CD38 is a glycoprotein expressed at a low level in myeloid and lymphoid tissues. However, it is highly and homogeneously expressed in plasma cells (PC) in multiple myeloma. Daratumumab is a human CD38-specific IgG1 antibody available for the treatment of multiple myeloma in Colombia. It has been authorized in relapsed/refractory disease as front-line treatment for non-eligible stem cell transplantation patients by INVIMA (Instituto Nacional de Vigilancia de Medicamentos y Alimentos) that is the regulatory agency. Daratumumab treatment has been associated with the negativization of the expression of CD38 in PC, demonstrating a resistance mechanism under the clonal evolution theory. We report the case of a 63-year-old male, diagnosed with a relapsed/refractory multiple myeloma, heavily treated, who expressed strong CD38 marker at the beginning of the treatment, with a posterior negativization of CD38 after four cycles of treatment with daratumumab.

Genetic heterogeneity of thalassemias in Mexican mestizo patients with hemolytic anemia

Twenty-eight Hb abnormalities (16 thalassemias, 10 Hb variants and 2 hereditary persistences of fetal hemoglobin) were detected in an etiopathogenic search in 131 patients with hemolytic anemia. The observed thalassemic genotypes [6 beta(0)/beta, 2 (delta beta) (0)/beta(0), 2 beta(0)/beta(+), 2 beta(0)/beta(s), 2 beta(+)/beta(+), 1 beta(+)/beta(s) and 1 (delta beta)(0)/beta] showed heterogeneity in the population studied. A native origin of some of these mutations is considered.

[The assessment and nutritional support of patients with the acquired immunodeficiency syndrome]

Given the negative effect of malnutrition on the immune function, the possibility must be considered that this also affects the clinical progression of AIDS patients. This study was aimed at assessing the state and nutritional support indicated for patients diagnosed as having AIDS. 114 patients admitted to our hospital in the period 1990-1991 were studied, with assessment of the nutritional state by means of anthropometric parameters (weight, size, tricipital fold, arm muscle circumference), biochemical parameters (albumin, lymphocytes, transferrin, RBP) and the treatment prescribed. Average age was 31.44 +/- years, 81.5% were male, 68% parenteral drug addicts. 71% had a stage IV C diagnosis. 37.72% had diarrhea before beginning treatment. The malnutrition diagnosed was as follows: moderate, 50.89%, severe 36%, slight, 12.5%, and mixed (calorific-protein), 62.5%, calorific 34.8%, and protein 2.6% of cases, 33% of the patients received dietary supplements, 33.84% enteral alimentation and 33% parenteral alimentation. Nutritional support was suspended as follows: improvement, 54.46%; transfers, 1.79%; death, 27.68%, and terminal situation, 16.07%. Deceased or terminal patients were more severely malnourished (p < 0.001) than the remainder. AIDS patients are studied and treated nutritionally in a very advanced stage of the illness, with severe malnutrition which conditions a poorer evolutive diagnosis. This suggests a change of attitude, with assessment being necessary of nutritional state and the appropriate therapy at the time of diagnosis, in order to slow the progression of the illness.

[Changes in hemoglobin in patients with hemolytic anemia]

Hb alterations studied throughout 2 years in 129 patients are reported, these patients had hemolytic anemia or the possibility of a hemoglobinopathy : 5 were heterozygotes to thalassemia b; 3 were compound-heterozygote of thalassemia a1 and thalassemia a2; 2 for thalassemia b and 2 for thalassemia b and Hb S; 2 homozygotes and 2 heterozygotes for Hb S; 2 was bearing unstable Hb and the other had Hereditary Persistence of Hb F. These results allow the conclusion that thalassemia is the Hb alteration which most frequently causes hemolytic anemia in our population and underscores the importance of the study of these pathologies in selected populations.

[Bilateral nodular hyperplasia of the adrenal glands; diagnostic problems]

Bilateral adrenal nodular hyperplasia (BAND) is rarely presented as a cause of Cushing Syndrome. The pathogenicity of the disease is unknown and it does not present either symptoms or specific signs, furthermore, its steroid dynamic is atypical and the morphologic tests are not conclusive. The clinical stories of six BAND-diagnosed patients in our Department have been reviewed with the aim of unifying the criteria of the preoperative diagnosis with regard to treatment, comparing our results with literature's wider series. The results from both studies demonstrate an hypophyseal dependence together with some others showing a adrenal autonomy. Thus, our conclusions perpetuate the pathogenic question about BAND (whether is an adrenal primary disfunction or a secondary effect caused by hypophyseal ACTH hypersecretion?) and we point out the usefulness of radioisotopic gammagraphy and abdominal-TAC, since usually they show the bilaterality of the injury at adrenal level.